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COMPARISON OF SKELETAL AND DENTOALVEOLAR EFFECTS OF THE FORSUS AND MARA IN TREATMENT OF CLASS II MALOCCLUSIONS Shereen Azizollahi, D.D.S. An Abstract Presented to the Graduate Faculty of Saint Louis University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Dentistry (Research) 2012 Abstract Purpose: The objective of this study was to compare the skeletal and dental effects of the Forsus and the MARA, which are two types of compliance-free interarch appliances. Materials and Methods: This study was a retrospective clinical investigation that included 25 MARA patients (13 females, 12 males) with a mean start age of 12.7 ± 0.8 years and 25 Forsus patients (13 females, 12 males) with a mean start age of 12.1 ± 1.3 years. The MARA and Forsus were matched according to age, gender, and cervical maturation stage at the start age. Pre-treatment (T1), appliance removal (T2), and posttreatment (T3) cephalograms were hand traced; and compared with the pitchfork analysis. The dental and skeletal effects of each fixed inter-arch appliance were analyzed using independent t-tests to compare the differences between each treated sample. Results: The MARA and Forsus both demonstrated a general trend of forward skeletal movement of the maxilla and mandible, with greater movement in the mandible. However, the MARA group showed a significantly greater amount of forward movement of the maxilla and mandible than the Forsus group. Greater proclination of the lower incisors was observed in the Forsus group during T1-T2. The overall median treatment duration of the Forsus was shorter than the MARA. Conclusions: The Forsus and the MARA are both effective compliance-free interarch appliances for Class II correction. In comparison to the MARA, the Forsus has a greater restraint on the maxilla. However, the MARA produces significantly greater forward displacement of the mandible than the Forsus. The Forsus may produce greater lower incisor proclination than the MARA in the correction of overjet. 1 COMPARISON OF SKELETAL AND DENTOALVEOLAR EFFECTS OF THE FORSUS AND MARA IN TREATMENT OF CLASS II MALOCCLUSIONS Shereen Azizollahi, D.D.S. A Thesis Presented to the Graduate Faculty of Saint Louis University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Dentistry (Research) 2012 COMMITTEE IN CHARGE OF CANDIDACY: Professor Eustaquio A. Araujo, Chairperson and Advisor Adjunct Professor Peter H. Buschang Associate Clinical Professor Donald R. Oliver i Dedication To my husband Jonathan, for believing in me and encouraging me in the pursuit of my career. You have brought laughter and love into my life. To my brother Elliot, for being supportive and always someone I can rely on. To my parents Arsalan and Nasrin, for their unconditional love and support. I would not be where I am today without them. They came to this country with no family and money, but the will to create a more beautiful life for my brother and I. A special thanks to my mom, who has been my role model. She graduated dental school from Tehran University in Iran and moved to the United States with the determination to attain her dental license in America. With her perseverance, she has motivated me to pursue my dreams. ii Acknowledgements I would like to acknowledge the following individuals, without their support this research project would not be possible: Dr. Eustaquio Araujo, my mentor and chairperson, he has been there whenever I needed guidance throughout this process. I feel honored to have him as my instructor with his vast knowledge in orthodontics and life. Dr. Donald Oliver, who is an invaluable part of this school and his dedication to the students and patients, is beyond measure. He supported me throughout this research process and was always someone I could depend on for help. Dr. Peter Buschang, I am thankful for his help with my study design and his enthusiasm in my research. Dr. Rolf Behrents, my program director, for giving me the opportunity to be a part of this orthodontic program. I am forever grateful for this experience. Dr. Valmy Pangrazio-Kulbersh, who not only provided me with the MARA sample, but was gracious enough to help me with the research design and so much more beyond her call of duty. Dr. Lisa Alvetro and her staff, for providing me with the Forsus sample and answering any questions I had promptly. Dr. Alex Tsourakis, my fellow colleague, for his help with any questions I had regarding the pitchfork analysis. Dr. Hiroshi Ueno, my fellow colleague, for his help with my statistics. iii TABLE OF CONTENTS LIST OF TABLES .........................................................................................................vi LIST OF FIGURES .......................................................................................................vii CHAPTER 1: INTRODUCTION ................................................................................... 1 CHAPTER 2: REVIEW OF LITERATURE Class II Problem Defined ............................................................................... 3 Prevalence of Class II malocclusion ............................................................... 3 Etiology of Class II malocclusions ................................................................. 4 History of Class II correction.......................................................................... 6 One Phase versus Two Phase Treatment ......................................................... 8 Role of Compliance in Treatment ................................................................... 9 Compliance Free Interarch Appliances ......................................................... 11 Herbst....................................................................................................... 11 Mandibular Anterior Repositioning Appliance (MARA) .......................... 14 Mandibular Protraction Appliance (MPA) ................................................ 16 Jasper Jumper ........................................................................................... 17 Forsus....................................................................................................... 19 Summary and Statement of Thesis ................................................................ 22 References.................................................................................................... 23 CHAPTER 3: JOURNAL ARTICLE Abstract........................................................................................................ 26 Introduction.................................................................................................. 28 Methods and Materials ................................................................................. 30 Sample ..................................................................................................... 30 Data Collection......................................................................................... 32 Statistical Methods ................................................................................... 34 Results ......................................................................................................... 34 Forsus and MARA Treatment Effects (T1-T2).......................................... 34 Forsus and MARA Post-Treatment Effects (T2-T3).................................. 37 Forsus and MARA Overall Treatment Effects (T1-T3) ............................. 40 Discussion .................................................................................................... 43 Maxillary Skeletal Effects ........................................................................ 44 Mandibular Skeletal Effects ...................................................................... 45 Maxillary Dental Effects........................................................................... 46 Mandibular Dental Effects ........................................................................ 46 Overall Effects ......................................................................................... 47 Conclusions .................................................................................................. 48 References.................................................................................................... 49 iv Appendix ....................................................................................................................... 51 Vita Auctoris ................................................................................................................. 52 v LIST OF TABLES Table 3.1: Median Treatment Duration and Inter-quartile Range (months) ................. 31 Table 3.2: Age, gender and cervical vertebral maturation stage-matched Forsus and MARA samples ....................................................................... 32 Table 3.3: T1-T2 Pitchfork comparison of Forsus and MARA ................................... 37 Table 3.4: T2-T3 Pitchfork comparison of Forsus and MARA ................................... 40 Table 3.5: T1-T3 Pitchfork comparison of Forsus and MARA ................................... 43 Table 3.6: Comparison of the Forsus appliance effects reported in the literature......... 44 Table 3.7: Comparison of the MARA appliance effects reported in the literature ....... 44 Table A.1: Description of pitchfork analysis variables ................................................. 51 vi LIST OF FIGURES Figure 3.1: Pitchfork analysis diagram ....................................................................... 33 Figure 3.2: Pitchfork treatment changes from T1-T2 in Forsus Sample ...................... 35 Figure 3.3: Pitchfork treatment changes from T1-T2 in MARA Sample ..................... 36 Figure 3.4: Pitchfork treatment changes from T2-T3 in Forsus Sample ...................... 38 Figure 3.5: Pitchfork treatment changes from T2-T3 in MARA Sample ..................... 39 Figure 3.6: Pitchfork treatment changes from T1-T3 in Forsus Sample ...................... 41 Figure 3.7: Pitchfork treatment changes from T1-T3 in MARA Sample ..................... 42 vii CHAPTER 1: INTRODUCTION Class II malocclusions are frequently encountered in orthodontics. Approximately 15% of the population has a Class II malocclusion according to the NHANES III study from 1988 to 1991.1 There are many different dental and skeletal combinations that can create a Class II malocclusion. However, mandibular retrusion is one of the most common characteristics.2 There are various techniques to correct Class II malocclusions including headgear, elastics, removable and fixed appliances, extractions and even surgery. But, often the limiting factor in achieving the ideal treatment result in orthodontics is compliance. By removing the burden of compliance from the patient, the practitioner is able to achieve more predictable results with reasonable treatment durations.3 Thus, many clinicians use compliance-free interarch appliances in order to correct Class II malocclusions. There are many different compliance-free appliances including the: Herbst, Mandibular Anterior Repositioning Appliance (MARA), Mandibular Protraction Appliance, Jasper Jumper and Forsus. All of these appliances can improve Class II malocclusions, but each one has advantages and disadvantages. An advantage of some of these appliances is the ability to use them in conjunction with comprehensive fixed therapy. However, some side effects from these fixed interarch appliances may be lower incisor proclination4-10 and upper molar tipping.10 Examples of appliances that can be used simultaneously with fixed treatment are the Forsus and MARA. 1 The MARA is a fixed functional appliance made in the laboratory that was introduced by Eckhart and Toll and launched by Ormco to the orthodontic community.11 The MARA is fixed with maxillary and mandibular stainless steel crowns on the first molars, which produce an interference that is designed to position the mandible forward. There have been numerous studies on the skeletal and dental effects of the MARA9,12-14 and its comparison to other fixed functional appliances.13 The Forsus Fatigue Resistant Device is a fixed Class II appliance that was developed by Vogt.15 It is prefabricated intermaxillary push spring that is composed of a push rod that inserts into a telescoping cylinder.16 The push rod, which the mesial end of the appliance, is attached to the mandibular archwire distal to the canine or first premolar bracket. The telescoping cyclinder is the distal end of the appliance and is inserted into the maxillary molar headgear tube.16 Previous investigations have evaluated the effects of the Forsus7,8,15 and compared it to intermaxillary elastics7 and untreated controls.8 While the skeletal and dental effects of the MARA and Forsus have been previously studied, 8-10,13-16 these two appliances have not been compared to one another. The objective of this study is to compare the skeletal and dental effects of the MARA and Forsus at three timepoints. Moreover, this investigation will assess the possible side effects of the appliances, including lower incisor proclination and molar tipping. The treatment duration will also be recorded for each appliance due to the relationship between treatment time and cooperation.17 2 CHAPTER 2: REVIEW OF THE LITERATURE The Class II Problem Defined In the 1890s Angle provided the first formal definition of normal occlusion in the natural dentition.11 Angle’s definition was based on the upper first molar, which was the “key to occlusion.”11 The mesiobuccal cusp of the upper first molar should occlude in the buccal groove of the lower first molar on a smooth curving line of occlusion. Angle also described three classes of malocclusion, one of which was the Class II. This was illustrated as the lower molar distally positioned relative to the upper molar. After World War II, cephalometric radiography became more commonly used in orthodontic treatment planning.11 With this new method of diagnosis, it was more apparent that the jaw relationship as well as the dental relationship contributed to the Class II malocclusion.2,11 Prevalence of Class II Malocclusions The Class II malocclusion is a common skeletal problem seen in orthodontics. From 1966 to 1970 the Division of Health Examination Statistics performed a National Health Survey, which collected data about the health of the U.S. population between the ages of 12 to 17.18 The survey studied the occlusion of these adolescents from a sample of approximately 7,500. One part of the survey observed buccal segment relationships among these adolescents. They described the Class II malocclusion as “distoclusion,” characterized by the “lower molars occluding with the upper molars behind the normal position.”18 They found that 32% of the adolescents had Class II malocclusions (unilateral and bilateral). Caucasians had a significantly larger percentage of Class II 3 malocclusion with 33.6% as opposed to 18.0% in the African American population. In this survey, the amount of overjet was also evaluated and it was found that about 15% of the population had a severe overjet that was considered greater than 5 mm.18 In the third National Health and Nutrition Examination Survey (NHANES III) conducted from 1988 to 1991, the prevalence of malocclusion and orthodontic treatment need in the United States was studied from a sample of 7,000 people.1 Class II malocclusions were considered when there was 5 mm or more overjet. Similar to the National Health Survey from 1966 to 1970, Class II malocclusions were observed in approximately 15% of the population.1,18 Slightly increased overjet of 3-4 mm was seen in about 40% of the population, which was about the same as the ideal overjet of 1-2 mm. Moreover, with an increase in age, the prevalence of excessive overjet declined probably due to late mandibular growth. In fact, over 20% of children from age eight to eleven years are considered to have a Class II malocclusion. This number plummets to 13% in adulthood. Class II malocclusions are more common in Caucasians than African Americans.1,18 However, severe Class II malocclusions that are seen in about 4% of the population are more common in African Americans and Mexican-Americans. This study portrays that the Class II skeletal problem is the most frequent jaw discrepancy found in the United States.1 Etiology of Class II Malocclusions With the large number of Class II malocclusions, there has been a great deal of focus on its nature throughout orthodontic literature. In 1981, McNamara dissected the components of the Class II malocclusion in his study of 277 children eight to ten years of 4 age.2 Specifically, he looked at the frequency of each component including the: maxillary skeletal position, maxillary dental position, mandibular dental position, mandibular skeletal position, and vertical in the Class II patient. The component that was the most common characteristic in his study was mandibular skeletal retrusion. He discussed that only a small percentage of subjects in his study portrayed maxillary skeletal protrusion. In fact, his study showed that the maxilla was usually in a neutral position. If the maxilla was not in the neutral position then it was more likely to be in a retruded than protruded position. Interestingly, maxillary skeletal retrusion was often seen with excessive vertical development. Even though there was a large range of vertical development in his sample, excessive vertical development was a frequent finding that, according to the author, may be attributed to an altered respiratory function. As far as dental relationships, he explained that the lower incisors were normally well positioned and the amount of maxillary dental protrusion was less frequently displayed than what was previously reported in other studies. Overall, his results illustrated that the nature of the Class II malocclusion is not a result of a single component, but a variety of different dental and skeletal combinations.2 In a longitudinal study by Buschang and Martins, the differences of anteroposterior (AP) and vertical changes were assessed between childhood and adolescence.19 The sample consisted of 49 females and 50 males that had approximately equivalent amounts of Class I and Class II subjects. These individuals were followed during childhood and adolescence between 6 to 15 years of age and lateral cephalograms were taken annually. Childhood skeletal changes were evaluated in females between 6 to 10 years of age and in males 8 to 12 year of age. Adolescent skeletal changes were 5 observed in females between 9 to 13 years of age and in males 11 to 15 years of age. The results showed that AP changes were largely due to the differential growth of the mandible rather than the maxilla. Furthermore, there was a greater tendency for AP discrepancies to decrease or improve during childhood as opposed to adolescents. Also, this study demonstrated that AP discrepancies had a greater likelihood of increasing during adolescence. Those subjects whose AP relationship improved portrayed a different pattern of developmental growth in comparison to those whose AP relationship worsened. Buschang and Martins explain that this increase in AP discrepancy that is more apparent during adolescence is usually due to a deficiency in mandibular growth. As far as vertical changes, there were greater changes in vertical during adolescence than childhood. Moreover, Buschang and Martins observed a relationship between AP and vertical changes. In about 29% of the females and 34% of the males, this study found that there were greater than average changes in the vertical and AP relationships. In the subjects that the AP relationships decreased, 34% to 37% were likely to have less than average increases in vertical changes. Furthermore, those with the greatest increases in AP relationships tended to have the greatest increases in vertical relationships. History of Class II Correction As mentioned in the study by Buschang and Martins the growth of the mandible is developmental in nature and occurs during childhood as well as adolescence.19 In Class II individuals whose AP discrepencies worsened during growth, there was less anterior movement of pogonion19. Thus, it is doubtful that skeletal growth will provide more than 3-4 mm to help correct a Class II malocclusion.11 6 Throughout the history of orthodontics there have been many ways to correct a Class II malocclusion. Some methods focus on orthopedic change while others affect dental changes alone. Beginning in the late 1800s Americans used extraoral forces to the maxilla. The idea behind this was to prevent the growth of maxilla and subsequently allow differential growth of the mandible.11 Headgear treatment could also be used for dental change alone by distalizing molars or maintaining their position. Although, headgear use was successful it was overcome by a new wave of thought by Angle and his followers.11 Angle, who did not believe in extraction, thought that Class II elastics would be a simplified way to correct Class II malocclusions by growing the mandible forward.11 Today, we know that effects of elastics are solely dental. At that time Angle’s beliefs were disputed by Case, who believed that extractions were sometimes necessary when long term stability and esthetics were questionable in non-extraction patients with protrusion, crowding, or skeletal discrepancies.11 Case’s concerns with non-extraction were echoed in the 1930s with Charles Tweed, who frequently found relapse in his nonextraction treatments.11 After presenting his retreated four bicuspid extraction patients at an orthodontic meeting, he reintroduced extraction treatment into the orthodontic community.11 Another method of Class II treatment, which came about toward the end of the nineteenth century by Kingsley and Case was the “bite jumping appliance.”20 The device by Kingsley was tooth-borne and used upper anterior guide planes to push the mandible forward upon closure.20 Later Robin developed the monobloc for infants with underdeveloped mandibles, which was a tissue-borne device.20 This concept of jumping the bite was described by Wolff and Roux to create “functional stress” or “shaking of the 7 bone” on the internal bony structure that would help shape and stimulate bone growth.20 Today, there are many different types of removable as well as fixed functional appliances that are used to distalize the maxillary dentition and bring the mandibular dentition forward. More recently, fixed intra-arch appliances have been used to distalize the maxillary dentition. Furthermore, fixed inter-arch appliances utilizing upper and lower dentition simultaneously help correct Class II malocclusions. When the jaw discrepancy is so severe that it is out of the realm of orthodontics, then orthognathic surgery can also be an option to treat Class II patients. This can be done in a one or two jaw surgery depending on the soft tissue profile of the individual. With each of the treatment options mentioned above, one is capable of treating a Class II patient. However, the severity of the Class II problem has an effect on the treatment rendered. Moreover, with each appliance or technique used there are advantages and disadvantages. One Phase versus Two Phase Treatment Once cephalometric radiography became a regular part of treatment planning in orthodontics it became apparent that the Class II correction with “functional” appliances as well as intermaxillary elastics was more dentoalveolar than skeletal. However, in the 1980s functional appliances came back into play with questions of whether or not they really stimulate mandibular growth. In 1995, a study by Livieratos and Johnston compared one-stage (edgewise) treatment versus two-stage (functional/edgewise) nonextraction treatment.21 According to Liveratos and Johnston both groups achieved 8 molar and overjet correction largely from skeletal changes yet the two groups were virtually “indistinguishable.” The functional active phase had a greater increase in the rate of growth, which declined during the fixed phase. Therefore, the overall amount of growth was not significantly different between the two samples. The functional appliance basically placed a “mortgage” on the growth of the mandible.21 Moreover, the two-phase treatment took an average of a year and a half longer than the one-phase treatment.21,22 This was later supported in a randomized clinical trial at University of North Carolina in which preadolescent children with overjet greater than 7 mm were randomly assigned to observation, headgear, or functional appliance treatment for 15 months and then later treated with fixed appliances.22 The results showed that there were little skeletal differences between the groups at the end of treatment.22 Furthermore, more patients in the functional group required extractions during the second phase of treatment.22 There may be an “acceleration” of growth seen in the early treatment but overall no significant “net gain.”22 Therefore, early treatment with headgear or functional appliances may not be as efficient as one-phase treatment, but this does not mean that it is never indicated.11 For instance, children with self-esteem issues due to their dental appearance and those more likely to have incisal trauma due to protruded incisors can benefit from early treatment.23 Also, in cases where patients are non-compliant, a fixed functional appliance could be an option. Role of Compliance Compliance can play a crucial role in a successful orthodontic treatment. In fact, there have been many studies on compliance in the literature. In the treatment of Class II malocclusions patient cooperation may consist of wearing headgear, intermaxillary 9 elastics, or removable functional appliances. Brandão evaluated compliance objectively using a timing device.24 Patients were asked to wear their headgear for 14 hours a day for a given number of days. These headgears had recorders that patients were not told about. However, they were told to track their wear times during this time. After a period of time patients were told that their headgear use would be monitored electronically. The conclusions showed that patients tend to “over report their headgear wear times.” The patients tend to only wear their headgear 56.7% of the actual time asked by the providers. There was an increase to 62.7% when patients were aware a recording device was being used. Interestingly, boys were more compliant than girls in this study. However, once they learned there was an electronic recording device, the girls had improved compliance.24 In another study, subjective versus objective methods of monitoring compliance with headgear use were evaluated by comparing questionnaires with a headgear timing device.17 The results showed there were “significant differences among the estimates of orthodontists, patients, parents and headgear timer scores.” It appeared that subjective measures may result in overestimation of compliance.17 However, subjective measures are usually the only source available to assess compliance.25 This makes it very difficult to determine whether or not a patient is compliant or noncompliant. In general, younger patients are more compliant than older patients.17,24,26 Furthermore, patients in treatment less than 8 months wore their headgear longer and more often than patients treated more than 8 months.17 Being able to predict patient compliance can intercept problems during treatment, so that treatment can be changed to decrease the need for cooperation. Therefore, having “identifying characteristics” of this problem can be helpful. However, predicting 10 cooperation is multi-factorial and it is extremely complex.27 Thus, there is a dilemma when working with poor cooperators because not only are the treatment results unreliable and unpredictable, but the treatment time is also longer.3,28 Patient’s whose treatment is not done in a timely manner maybe less likely to refer patients to their orthodontist.28 Furthermore, Skidmore says that Class II malocclusions usually have longer treatment times.29 Thus, Class II correctors that reduce compliance could be advantageous because they can reduce the reliability on the patient so that more predictable results can be attained.3 Compliance-Free Interarch Appliances Compliance-Free Appliances are attached to the maxilla and the mandible and are used when a limited amount of compliance is required. In Class II correction, they are used to posture the mandible forward; in effect bringing the lower dentition forward and the upper dentition back. Some of these appliances include the: Herbst, MARA, MPA, Jasper Jumper, and Forsus. Herbst The Herbst appliance was developed by Herbst in 1905 and presented at the 1909 International Dental Congress in Berlin.20,30 However, the appliance did not gain popularity until 1979 when Pancherz revived this Class II treatment therapy in the orthodontic community.30 In his study, Pancherz describes the “continuous bite jumping” effect of this fixed functional appliance and its advantage in patient cooperation, which appealed to many clinicians.30 11 The design of the Herbst is a bilateral telescoping mechanism that protracts the mandible in a forward position.20,30 The components of this telescoping mechanism consist of a tube and plunger that fit together and are attached to the maxillary molar and mandibular premolar bands with screws. At this point of attachment the tube and plunger are able to rotate freely like an “artificial joint between the maxilla and mandible.”30 A lower lingual holding arch is standard and often a TPA or palatal expander is used in conjunction with this appliance. In Pancherz 1979 study, 10 Class II subjects were treated with the Herbst for a 6 month period and another 10 Class II subjects were observed for a 6 month period.30 According to Pancherz, the mandibular length increased 3.2 mm in the treated subjects and 1.0 mm in the control. There was also a decrease in ANB,that consisted of a decrease in SNA by 0.7° and an increase in SNB by 1.2°. Pancherz suggested that these results indicated a restraint in the maxilla and stimulation of growth in the mandible. He also mentioned an increase in the vertical dimension with an increase in lower facial height. Overall, there was a 3.8 mm decrease in overjet and 2.5 mm decrease in overbite. In a later study, Pancherz included 22 Class II subjects and 20 controls, which showed that the Class II was corrected with skeletal and dental changes. The overall treatment effect had a 6.7 mm molar correction that was mostly a result of increase in mandibular length of 2.2 mm, 1.0 mm forward movement of mandibular molars and 2.8 mm distalization of maxillary molars. The overjet correction was also greatly due to the increase in mandibular length mentioned above and the forward movement of mandibular incisors of 1.8 mm. There was a minimal amount of restriction of growth from the maxilla, with 0.4 mm. Fifteen years later, Pancherz looked at the long term effects of the 12 Herbst appliance in a prospective study.31 He found that although there was an increase in mandibular growth during treatment most of this effect was not retained long term. Moreover, there can be a “headgear effect” on the maxilla, but this is transient without appropriate retention. This finding was supported in the study by Lai and McNamara in 1998.6 However, in this study the Herbst appliance was an acrylic splint type, which is said to have more control over lower incisor proclination. Forty Class II subjects were treated with the Herbst for 12 months and were matched to 40 subjects from a Class II untreated sample from The University of Michigan Elementary and Secondary School Growth Study. Lateral cephalograms were taken before treatment, after Herbst removal, and after phase-II edgewise treatment. Long term effects showed that during Herbst treatment the rate of mandibular growth increased, but this declined during the second phase. Thus at the end there was small increase in mandibular length (1 mm) compared to controls. In the maxilla there was a significant decrease in SNA that was seen in both phases. The main dental effects at the end of phase II in the Herbst were forward movement of the mandibular dentition with proclination of lower incisors. Also, the maxillary molars and lower incisors were restrained from eruption while the mandibular molars were free to erupt. In general, the skeletal effects in the Herbst phase improved 55% of the molar correction while in the second part of treatment improved 80% of the molar correction. The advantages of the Herbst appliance are the ability to treat a patient’s Class II malocclusion without major patient compliance, the wealth of documentation, accessibility and the ability to make modifications to its design. There are some pitfalls to this treatment, which include: the patients’ likelihood of “burn out” because of long 13 treatment, cost of laboratory fabrication, breakage, use of specially made crowns, and its rigidity that makes lateral mandibular movements difficult.20 Mandibular Anterior Repositioning Appliance The Mandibular Anterior Repositioning Appliance (MARA) is a fixed functional appliance often used as a non-compliant appliance for Class II patients. In 1998 it was launched by Ormco after being developed by Eckhart and Toll.11 The MARA is comprised of maxillary and mandibular first molar stainless steel crowns that produce an interference with one another in order to push the mandible forward. This interference is accomplished through a vertical bar that is attached to the upper first molar crown also known as the “elbow” and a horizontal bar attached to lower first molar extending out buccally, which is also known as the “arm.” Thus, when the “elbow” meets the “arm” the patient is forced into a Class I malocclusion. If subsequent activations are necessary, then shims can be added. It is standard to have a lower lingual holding arch, but TPA’s and expansion screws can also be added.20 In a study by Pangrazio-Kulbersh, 30 Class II patients were treated with the MARA.9 There were 12 boys with an average age of 11.2 years and 18 girls with an average age of 11.3 years in the treated group. There were also 21 Class II untreated subjects for the control from the Michigan Growth Study. Two cephalograms were taken, one pretreatment that was 2 weeks before treatment, and a post-treatment cephalogram 6 weeks after removal of the MARA. The average treatment time was 10.7 months. Pangrazio-Kulbersh’s results showed that the MARA produces 5.8 mm of Class II molar correction; 47% of which was skeletal and 53% that was dental. However, the 14 orthopedic effects were solely in the mandible. There was no “headgear effect”, which is often seen with the Herbst appliance. According to Pangrazio-Kulbersh, there was an increase in mandibular length, the chin point moved forward and ANB decreased in the MARA group. Also, there was an increase in anterior and posterior face height. However, there were no significant vertical dental movements in the mandibular teeth. The dental movements observed were mainly due to distalization of the maxillary molar. There was also forward mandibular molar and incisor movement and mild proclination of the mandibular incisor.9 A study by Gönner showed that there was less lower incisor movement with the MARA than with other fixed Class II appliances such as the Cantilever Bite Jumper, Clip-on Twin Block, Jasper Jumper, or Forsus.12 Later in a study by Siara-Olds et al., the long-term dentoskeletal effects of the Bionator, Herbst, Twin Block and MARA were examined.13 There were 80 treated subjects with 20 Class II subjects within each treatment group. The control consisted of 21 matched Class II untreated subjects from the Michigan Growth Study. Lateral cephalograms were taken at three timepoints: initial, completion of functional therapy, and completion of fixed therapy. This study found no significant difference in “longterm dento-skeletal” movements between the control and treated samples.13 When compared to other functional appliances, the MARA after the Herbst had a significant impact on the restraint of the maxilla, which is in contrast to Pangrazio-Kulbersch’s previous findings. In a more recent study by Ghislanzoni et al., the treatment and post-treament orthopedic and dental outcomes of the MARA were evaluated.14 There were 23 patients treated with the MARA appliance. Cephalograms were taken pretreatment, post-MARA, 15 and at least 1 year after post-MARA. The control sample was comprised of 17 untreated Class II subjects from the University of Michigan and Denver Child Growth Studies. Fixed appliances were often used concurrently with the MARA or after a few months of active treatment. Lower molars were also stabilized with a lower lingual holding arch. During the active part of treatment, the lower incisor came forward and there was an increase in mandibular length. However, long term there was some relapse in the incisor proclination. Moreover, there were significant orthopedic effects seen in the mandible as well as the maxilla long term. The mandible had 2.0 mm increase in length Co-Gn and there was restriction of the maxilla, with SNA decreasing 1.2°.14 There are many advantages of the MARA when compared to the Herbst including its ability to be used with full fixed appliances, it is more esthetic, it has fewer problems with breakage and disengagement, and it can be activated unilaterally. The disadvantages of the MARA include the need for stainless steel crowns which can cause an increase in anterior face height and molar mobility. Mandibular Protraction Appliance The Mandibular Protraction Appliance (MPA) was presented by Coelho in 1995.32 This appliance is similar to other fixed functional appliances because of its bite jumping ability with the advantage of being fabricated at the chair. It has been modified since Coelho introduced it with 4 different versions. The most recent model uses a tube and piston similar to a Herbst. The tube attaches through the distal of the headgear tube on the maxillary molar and the piston engages the lower archwire through a helix on the wire distal to the mandibular canine.5 16 A study comparing the MPA with the Herbst was performed by Alves and Oliveira in 2008, which looked at the skeletal, dental and soft tissue effects of each appliance.5 There were 43 Class II subjects in total with 15 subjects in the MPA sample, 12 subjects in the Herbst sample and 16 subjects in the control sample. The MPA group was treated an average of 8.3 months at an average age of 13 years and 2 months, the Herbst group was treated an average of 8.7 months at an average age of 12 years and 4 months and the control group was observed for 10 months starting at an average age of 10 years and 4 months. Lateral cephalograms were taken before placement of each appliance and at removal. The control group had two lateral cephalograms taken; one initial and 10 months later while being followed. The study concluded that there were statistically significant increases in mandibular length in both treated groups in comparison to the control, although the MPA group portrayed more growth than the Herbst. Moreover, both groups showed proclination of mandibular incisors and retrusion of the upper lip compared to the controls.5 Thus this appliance can be a low-cost alternative to a traditional laboratory fabricated fixed functional appliance. However, it has had a tendency toward breakage and archwire distortion in the past.20 Jasper Jumper The Jasper Jumper is an intermaxillary flexible force module that can be used in conjunction with existing fixed appliances.33 It is essentially made up of heavy coil springs in compression that are encased in an opaque plastic covering and postures the lower jaw forward. There are two ways to attach the Jasper Jumper: on the main arch wire or on an auxillary arch wire called an “outrigger.” In both methods the distal end of 17 the force module is attached to the upper arch by a ball pin that threads through the distal end of the headgear tube on the upper first molar. When placed on the main arch wire, the mesial end is attached to the lower arch wire distal to the mandibular canines. The removal of the lower premolars is recommended to allow the force module to move more freely. When using an outrigger, the premolar brackets can remain on and the force module’s mesial end is attached to the auxillary. This is basically a sectional wire attached to the distal end of the mandibular canine through the auxillary tube of the lower first molar.33 There have been many cephalometric based studies on the Jasper Jumper. In 1994 Cope et al. looked at 31 Class II subjects treated with the Jasper Jumper and compared them to 31 untreated Class II controls from the Human Growth Research Center at Montreal.10 The treatment time for the Jasper Jumper was 0.4 years and with a mean age of 12.9 years. Most of the Class II correction seen was dentoalveolar, with a slight maxillary skeletal restraint and no significant increase in mandibular length. In the maxilla, the molars had significant distal tipping and intrusion and the incisors were retroclined with extrusion. In the mandible, the molars moved forward with bodily movement as well tipping and were extruded. The mandibular incisors had a significant amount of proclination and intrusion.10 In 1999 Covell’s study supported Cope’s previous findings, which showed the significant amount of dental effects compared to skeletal effects created by the Jasper Jumper.4 In contrast, Weiland and Banteleon found a considerable amount of mandibular orthopedic effect in their study.34 They looked at 17 Class II subjects treated with the Jasper Jumper for 6 months with an average age of 11 years and 4 months at start and compared them to the Bolton standards of dentofacial 18 developmental growth. Lateral cephalograms were taken before insertion of the appliance and after its removal. Similar to Cope and Covell, Weiland and Banteleon found a limited skeletal effect on the maxilla and overall more dental than skeletal effects.5,10,34 However, they found a significant increase in mandibular length of 1.7 mm, an increase in SNB of 1.2°, and a forward movement of pogonion by 2.1 mm.34 Similarly, Stucki and Ingervall found markedly increased mandibular prognathism and only a slight retrusion of the maxilla.35 In general, the various studies have shown that the Jasper Jumper has mainly dentoalveolar effects, which were shown in Cope’s initial study.4,10,34,35 Although, the Jasper Jumper can be used as an effective method to correct Class II malocclusions it does have its drawbacks. It has a tendency towards breakage as shown in the study by Stucki and Ingervall who reported a 9% incidence of breakage.35 A couple other disadvantages are the large inventory needed and a lack of force when the mouth is slightly open.20 However, it can easily be adapted to a full banded case and limits the amount of chair time with its easy use.20 Forsus The Forsus Fatigue Resistant Device was developed by Vogt as a fixed Class II appliance.15 Vogt explains that the Forsus is an intermaxillary push spring that is comprised of a push rod which inserts into a telescoping cylinder.16 This push rod is attached onto the mandibular archwire either distal to the canine or first premolar brackets and will complement a comprehensive fixed appliance.16 The distal end of the telescoping tube attaches through the maxillary headgear tube with either an L-pin from 19 the distal or the EZ-module from the mesial in more recent models.16 The push rods come in four different sizes and when fully compressed produce about 200g of force. Usually, the force level is not this high and is comparable to heavy Class II elastics. It transfers its force on the maxillary molars by distalizing and intruding, while using the lower arch as anchorage.16 One study evaluated Forsus treatment over a 4 month period based on 13 Class II subjects with an average age of 14.2 years.15 Lateral cephalograms were taken before Forsus spring insertion and after removal. Also, a questionnaire was administered to the adolescents, which quantified how content the subjects were with the Forsus. The radiographs showed that about 66% of the anterior-posterior correction was due to dentoalveolar effects. The molar correction was improved by three-fourths a cusp width by distal movement of the maxillary molars and mesial movement of the mandibular molars. Furthermore, there was correction of the overjet by retrusion of the upper incisors by 5.3° and proclination of the lower incisors by 9.6°. A vertical force was also expressed with intrusion of the lower incisors and maxillary molars creating a clockwise rotation of the occlusal plane of 4.2°. Overall, the upper and lower arches were expanded during treatment with a greater effect in the upper arch. The questionnaire, which was taken two months after treatment start showed that nearly half of the patients had difficulty brushing their teeth. However, the major complaint was the restriction from yawning. In general, more than two-thirds of the adolescents preferred the Forsus to their previous compliant dependent Class II therapy.15 As mentioned above, Vogt suggests that the Forsus is a non-compliant treatment alternative to Class II elastics.16 In a study by Jones in 2008, 34 Class II subjects with 20 Class II elastic treatment with an average age of 12.6 years were compared to 34 Class II subjects with Forsus therapy with an average age of 12.2 years.7 Pretreatment and Posttreatment cephalograms were taken and analyzed using the pitchfork analysis and a vertical cephalometric analysis. Except for the amount of forward movement of the lower molars and total molar correction, there were no significant differences among the two groups. In the Forsus group, there was 1.1 mm greater forward movement of the lower molars and 0.8 mm greater molar correction compared to the intermaxillary elastics group. Both groups showed upper and lower molar extrusion and lower incisor proclination. Moreover, both the Forsus and elastics groups portrayed skeletal and dentoalveolar forward movement in the maxilla and the mandible, with more movement in the latter.7 In a more recent study by Franchi et al., the efficacy of the Forsus was tested against a control group.8 The Forsus sample consisted of 32 Cl II subjects with a mean of 12.7 years and the control was comprised of 27 matched untreated Class II subjects from the University of Michigan Growth Study and the Denver Child Growth Study with a mean age of 12.8 years. Lateral cephalograms of the treated patients were taken before treatment and at the end of comprehensive treatment. The average comprehensive treatment time was 2.4 years. This study evaluated both the dental and skeletal components of the Class II correction. Contrary to Jones study, Franchi suggests the maxilla was orthopedically restrained in the Forsus group, which was the major part of Class II correction skeletally. The SNA decreased 2.1° and Pt A to Nasion perp was restricted 1.2 mm in comparison to the controls, while mandibular length increased (CoGn) 1.8 mm. Similar to the previous studies, the lower incisors significantly proclined 21 and intruded and the mandibular molars came forward and extruded.7,15 Also, there was a significant correction in overjet and molar relationship.7,15 The Forsus has shown through previous studies to have dental as well as orthopedic effect. It is also adaptable to a fully fixed appliance and is pre-fabricated so it is easily accessible when needed. Similar to its predecessors it does have problems with breakage.36 However, it is the least likely to break in comparison to other intermaxillary compression springs.20 The Forsus does disengage when the mouth is opened beyond 60 mm, which may pose a problem and it is also costly.20 Summary and Statement of Thesis There have been various studies on fixed functional appliances. Some of these appliances, such as the Forsus and MARA, can be used in conjunction with complete fixed appliances, which poses an advantage. The MARA is a laboratory made appliance while the Forsus is pre-fabricated. The MARA and Forsus have both been shown to have skeletal and dental effects for Class II correction8,9,9,13,13,14, 15 To date, there has not been a direct comparison between these two appliances. The purpose of this study is to evaluate the skeletal and dental differences between these devices using lateral cephalograms at three timepoints: initial, after appliance removal and final. In the past studies of the Forsus, only two timepoints have been observed. Differences in treatment time between these appliances will also be recorded since this can be an important factor in patient cooperation. 22 References 1. Proffit WR, Fields HW Jr, Moray LJ. Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey. Int J Adult Orthodon Orthognath Surg. 1998;13:97–106. 2. McNamara JA Jr. Components of Class II malocclusion in children 8-10 years of age. Angle Orthod. 1981;51:177–202. 3. McSherry PF, Bradley H. Class II correction-reducing patient compliance: a review of the available techniques. J Orthod. 2000;27:219–25. 4. Covell DA Jr, Trammell DW, Boero RP, West R. A cephalometric study of Class II Division 1 malocclusions treated with the Jasper Jumper appliance. Angle Orthod. 1999;69:311–20. 5. Alves PFR, Oliveira AG. A comparison of the skeletal, dental, and soft tissue effects caused by Herbst and mandibular protraction appliances in the treatment of mandibular Class II malocclusions. World J Orthod. 2008;9:e1–19. 6. Lai M, McNamara JA Jr. An evaluation of two-phase treatment with the Herbst appliance and preadjusted edgewise therapy. Semin Orthod. 1998;4:46–58. 7. Jones G, Buschang PH, Kim KB, Oliver DR. Class II non-extraction patients treated with the Forsus Fatigue Resistant Device versus intermaxillary elastics. Angle Orthod. 2008;78:332–8. 8. Franchi L, Alvetro L, Giuntini V, Masucci C, Defraia E, Baccetti T. Effectiveness of comprehensive fixed appliance treatment used with the Forsus Fatigue Resistant Device in Class II patients. Angle Orthod. 2011;81:678–83. 9. Pangrazio-Kulbersh V, Berger JL, Chermak DS, Kaczynski R, Simon ES, Haerian A. Treatment effects of the mandibular anterior repositioning appliance on patients with Class II malocclusion. Am J Orthod Dentofacial Orthop. 2003;123:286–95. 10. Cope JB, Buschang PH, Cope DD, Parker J, Blackwood HO 3rd. Quantitative evaluation of craniofacial changes with Jasper Jumper therapy. Angle Orthod. 1994;64:113–22. 11. Proffit WR, Fields HW, Sarver DM. Contemporary Orthodontics. 4th ed. St. Louis: Mosby; 2007. 12. Gönner U, Ozkan V, Jahn E, Toll DE. Effect of the MARA appliance on the position of the lower anteriors in children, adolescents and adults with Class II malocclusion. J Orofac Orthop. 2007;68:397–412. 23 13. Siara-Olds NJ, Pangrazio-Kulbersh V, Berger J, Bayirli B. Long-term dentoskeletal changes with the Bionator, Herbst, Twin Block, and MARA functional appliances. Angle Orthod. 2010;80:18–29. 14. Ghislanzoni LTH, Toll DE, Defraia E, Baccetti T, Franchi L. Treatment and posttreatment outcomes induced by the Mandibular Advancement Repositioning Appliance; a controlled clinical study. Angle Orthod. 2011;81:684–91. 15. Heinig N, Göz G. Clinical application and effects of the Forsus spring. A study of a new Herbst hybrid. J Orofac Orthop. 2001;62:436–50. 16. Vogt W. The Forsus Fatigue Resistant Device. J Clin Orthod. 2006;40:368–77; quiz 358. 17. Bos A, Kleverlaan CJ, Hoogstraten J, Prahl-Andersen B, Kuitert R. Comparing subjective and objective measures of headgear compliance. Am J Orthod Dentofacial Orthop. 2007;132:801–5. 18. Kelly JE, Harvey CR. An assessment of the occlusion of the teeth of youths 12-17 years. Vital Health Stat 11. 1977;1–65. 19. Buschang PH, Martins J. Childhood and adolescent changes of skeletal relationships. Angle Orthod. 1998;68:199–206; discussion 207–8. 20. Graber T, Vanarsdall R, Vig K. Orthodontics: Current Principles and Techniques. 4th ed. St. Louis: Mosby; 2005. 21. Livieratos FA, Johnston LE Jr. A comparison of one-stage and two-stage nonextraction alternatives in matched Class II samples. Am J Orthod Dentofacial Orthop. 1995;108: 118–31. 22. Tulloch JF, Phillips C, Proffit WR. Benefit of early Class II treatment: progress report of a two-phase randomized clinical trial. Am J Orthod Dentofacial Orthop. 1998;113:62–72, quiz 73–4. 23. O’Brien K. Is early treatment for Class II malocclusion effective? Results from a randomized controlled trial. Am J Orthod Dentofacial Orthop. 2006;129:S64–5. 24. Brandão M, Pinho HS, Urias D. Clinical and quantitative assessment of headgear compliance: a pilot study. Am J Orthod Dentofacial Orthop. 2006;129:239–44. 25. Sahm G, Bartsch A, Witt E. Reliability of patient reports on compliance. Eur J Orthod. 1990;12:438–46. 26. Egolf RJ, BeGole EA, Upshaw HS. Factors associated with orthodontic patient compliance with intraoral elastic and headgear wear. Am J Orthod Dentofacial Orthop. 1990;97:336–48. 24 27. Nanda RS, Kierl MJ. Prediction of cooperation in orthodontic treatment. Am J Orthod Dentofacial Orthop. 1992;102:15–21. 28. Beckwith FR, Ackerman RJ Jr, Cobb CM, Tira DE. An evaluation of factors affecting duration of orthodontic treatment. Am J Orthod Dentofacial Orthop. 1999;115:439–47. 29. Skidmore KJ, Brook KJ, Thomson WM, Harding WJ. Factors influencing treatment time in orthodontic patients. Am J Orthod Dentofacial Orthop. 2006;129:230–8. 30. Pancherz H. Treatment of class II malocclusions by jumping the bite with the Herbst appliance. A cephalometric investigation. Am J Orthod. 1979;76:423–42. 31. Pancherz H. The effects, limitations, and long-term dentofacial adaptations to treatment with the Herbst appliance. Semin Orthod. 1997;3:232–43. 32. Coelho Filho CM. Mandibular protraction appliance IV. J Clin Orthod. 2001;35:18– 24. 33. Jasper JJ, McNamara JA Jr. The correction of interarch malocclusions using a fixed force module. Am J Orthod Dentofacial Orthop. 1995;108:641–50. 34. Weiland FJ, Bantleon HP. Treatment of Class II malocclusions with the Jasper Jumper appliance--a preliminary report. Am J Orthod Dentofacial Orthop. 1995;108:341–50. 35. Stucki N, Ingervall B. The use of the Jasper Jumper for the correction of Class II malocclusion in the young permanent dentition. Eur J Orthod. 1998;20:271–81. 36. Ross AP, Gaffey BJ, Quick AN. Breakages using a unilateral fixed functional appliance: a case report using The Forsus Fatigue Resistant Device. J Orthod. 2007;34:2–5. 25 CHAPTER 3: JOURNAL ARTICLE Abstract Purpose: The objective of this study was to compare the skeletal and dental effects of the Forsus and the MARA, which are two types of compliance-free interarch appliances. Materials and Methods: This study was a retrospective clinical investigation that included 25 MARA patients (13 females, 12 males) with a mean start age of 12.7 ± 0.8 years and 25 Forsus patients (13 females, 12 males) with a mean start age of 12.1 ± 1.3 years. The MARA and Forsus were matched according to age, gender, and cervical maturation stage at the start age. Pre-treatment (T1), appliance removal (T2), and posttreatment (T3) cephalograms were hand traced; and compared with the pitchfork analysis. The dental and skeletal effects of each fixed inter-arch appliance were analyzed using independent t-tests to compare the differences between each treated sample. Results: The MARA and Forsus both demonstrated a general trend of forward skeletal movement of the maxilla and mandible, with greater movement in the mandible. However, the MARA group showed a significantly greater amount of forward movement of the maxilla and mandible than the Forsus group. Greater proclination of the lower incisors was observed in the Forsus group during T1-T2. The overall median treatment duration of the Forsus was shorter than the MARA. Conclusions: The Forsus and the MARA are both effective compliance-free interarch appliances for Class II correction. In comparison to the MARA, the Forsus has a greater 26 restraint on the maxilla. However, the MARA produces significantly greater forward displacement of the mandible than the Forsus. The Forsus may produce greater lower incisor proclination than the MARA in the correction of overjet. 27 Introduction Individuals with Class II malocclusions comprise a considerable part of the population. In the National Health Survey from 1966 to 1970, Class II malocclusions (unilateral and bilateral) defined as “distoclusion” were found in 32% the population.1 Later in the NHANES III study from 1988 to 1991 Class II malocclusions, which were categorized as people with an overjet of 5 mm or greater, consisted of 15% of the population.2 The nature of the Class II malocclusion is due to a number of different dental and skeletal combinations, although one of the most common characteristics is mandibular skeletal retrusion.3 The correction of Class II malocclusions has been performed using headgears, elastics, removable and fixed appliances, extractions and even surgery. However, compliance has been a constant problem in orthodontic treatment. Using Class II appliances that reduce the need for compliance can be advantageous, since less responsibility is placed on the patient and more predictable results can be achieved.4 This has often lead practitioners to use fixed interarch appliances, which are compliance-free. The most commonly used fixed appliances include the Herbst, Mandibular Anterior Repositioning Appliance (MARA), Mandibular Protraction Appliance, Jasper Jumper, and Forsus. Each of these appliances can be effective in achieving Class I occlusion, but may have advantages and disadvantages. Some of these appliances can be used simultaneously with complete fixed treatment, which can be advantageous. Generally, the undesirable effects in these appliances include lower incisor proclination5-11 and upper molar distal tipping.10 In the case of both the MARA and Forsus, the appliances can be used in conjunction with complete fixed therapy. 28 The MARA is a laboratory made fixed functional appliance that was introduced by Ormco after being developed by Eckhart and Toll.12 It consists of upper and lower first molar stainless steel crowns that produce an interference with one another in order to protract the mandible.13 Many studies have looked at the effects of the MARA11,14-16 and compared them to other fixed functional appliances.15 The overall skeletal effects appear to include a short-term restraint of the maxilla and increase in mandibular length.15,16 The dental effects include mesial movement in the upper and lower molars.16 The upper and lower incisors have generally moved forward with lower incisor proclination.15,16 The Forsus Fatigue Resistant Device was developed by Vogt as a fixed Class II corrector.17 It is a prefabricated interarch push spring that is comprised of a push rod that inserts into a telescoping cylinder.18 The push rod is attached to the lower archwire either distal to the canine or first premolar bracket and the telescoping cylinder inserts into the upper molar headgear tube.18 In the previous studies of the Forsus8,9,17 the effects of the appliance have been compared to intermaxillary elastics8 and control samples,9 however, only two timepoints have been analyzed. Prior investigations have shown mesial movement of both the maxilla and mandible.8,9,17 The upper and lower molars have also been shown to move mesially.8,9,17 Also, existing literature shows a trend toward lower incisor proclination.8,9,17 In both the Forsus and MARA, skeletal and dental effects for Class II correction have been observed.8,9,11,14-17 However, there has not been a study that has compared these appliances side by side. The purpose of this study is to compare the skeletal and dentoalveolar effects of the MARA and Forsus to one another at three time points. Moreover, this study will evaluate the undesirable side effects, including lower incisor 29 proclination and upper molar tipping between the Forsus and MARA. Furthermore, the duration of each treatment will be recorded because of the significance with treatment time and cooperation.19 Materials and Methods Sample In this study Class II patients were treated non-extraction with fixed interarch Class II correctors. The subjects were from two private practices, one that treated with the MARA (Ormco) and the other treated with the Forsus (3M Unitek) (25 MARA and 25 Forsus). Lateral cephalograms were taken before treatment (T1), after interarch appliance removal (T2), and at the completion of fixed therapy (T3). The mean start age for the MARA sample was 12.7 ± 0.8 years and the Forsus sample had a mean start age of 12.1 ± 1.3 years. In the Forsus sample the median duration of treatment from T1-T2 was 21 months (IQR = 18.5 to 27 months) as shown in Table 3.1. During this period, the subjects were fully bonded; the Forsus was applied at the end of the leveling and aligning stage. The range that the Forsus was applied during T1-T2 was between 2 to 11 months, with a median of 5.5 months. In both the upper and lower arches, 0.019 x 0.025-inch stainlesssteel archwires were placed during Forsus treatment and consistently cinched back in the mandibular arch. After the Forsus was removed, T2, the subjects were in the finishing stages and the Class I correction was maintained. The median duration from T2-T3 in the Forsus was 6 months (IQR = 4 to 7 months). The total median treatment time, T1-T3, was 26 months in the Forsus group (IQR = 23 to 32 months). 30 In the MARA sample the median duration of treatment from T1-T2 was 13 months (IQR = 11 to 16 months) as shown in Table 3.1. During this time, the MARA was placed, but the subjects were not fully bonded. In all of the MARA subjects, a lower lingual holding arch was used. After the MARA was removed, T2, the patients were fully bonded for a median duration of 19 months (IQR = 14 to 24 months). During this time period, the patients were leveled and aligned and then finished while maintaining the Class I occlusion. The median duration of the comprehensive treatment in the MARA group was 33 months (IQR = 26 to 36.5 months). Table 3.1 Median Treatment Duration and Inter-quartile Range (months) Appliance Forsus MARA T1-T2 21 (18.5 to 27) 13 (11 to 16) T2-T3 6 (4 to 7) 19 (14 to 24) T1-T3 26 (23 to 32) 33 (26 to 36.5) In addition to treatment duration, the subjects’ gender, age, and cervical vertebral maturation stage20 at start age was recorded, so that the subjects could be matched based on gender, age and cervical vertebral stage at start age (Table 3.2). The cervical vertebral stage was recorded at start age using the cervical vertebral maturation (CVM) method.21 The median value for the CVM stage at T1 or start age was 2 (range of 1 to 4). The inclusion criteria for the subjects selected was the following: (1) initial Class II malocclusion, (2) no permanent teeth extracted, (3) lateral cephalograms of diagnostic quality taken at three time points and (4) correction of Class II malocclusion to Class I or super Class I occlusion. The treatment variability was also reduced by using samples that were only treated by one practitioner. After the removal of the Forsus or MARA (T2) 31 other Class II correctors, such as Class II elastics, may have been used in some patients in order to maintain the Class I occlusion. Table 3.2: Age, gender and cervical vertebral maturation stage- matched Forsus and MARA samples Appliance Males Mean Start Age (yrs) Females Forsus 12 13 12.7 ± 0.8 (11.6 - 15) MARA 12 13 12.1 ± 1.3 (9.3 – 15.3) Median CVM Stage T1 2 2 Data Collection The pre-treatment, appliance removal, and post-treatment cephalograms were digital radiographs. The magnification of the MARA sample was 0% while the Forsus had a magnification of 14%, which was adjusted for in the measurements. These were printed on photo quality paper and hand-traced on acetate paper using a 0.3 mm pencil. Measurements were performed using a digital caliper to the nearest tenth of a millimeter as recommended by Johnston.22 Superimpositions were performed between pretreatment (T1) and appliance removal (T2) and between appliance removal (T2) and posttreatment (T3) using the Pitchfork analysis explained by Johnston.22 The pitchfork analysis presents the changes in molar and incisor relationships as an algebraic sum of skeletal growth relative to the cranial base and dental movements relative to basal bone. The measurements are given a sign of positive or negative depending on the impact on the Class II relationship: a positive sign is used when the Class II molar relationship or overjet is improved and a negative sign is used when it is 32 worsened. The apical base change (ABCH) is the total amount of the maxillary and mandibular skeletal growth changes and signifies the overall effect of skeletal growth. The change in molar relationship is determined when the ABCH is added to the changes in upper and lower first molar movements. The change in overjet is found when the ABCH is summed with the changes in upper and lower incisor movements. These measurements are all made relative to the mean functional occlusal plane, which is determined from the average of T1, T2 and T3 functional occlusal planes. The functional occlusal plane is based on the first molars and premolars and the incisors are disregarded.22 Max + Mand = ABCH ABCH + U6 + L6 = 6/6 ABCH + U1 + L1 = 1/1 Figure 3.1: Pitchfork analysis diagram, adapted from Johnston.22 33 Because Class II interach appliances often produce angular changes to upper and lower incisors, the angles of these teeth were measured by hand relative to the mean functional occlusal plane. Also, the amount of tipping of the upper and lower molars was measured by subtracting the amount of root movement from crown movement. Statistical Methods The data was statistically analyzed using SPSS 17.0 for Windows (IBM). An independent two-sample t-test was performed to analyze the differences between the two groups. A Levene’s test was also done to evaluate the equality of variances. Differences among the groups were regarded as statistically significant at p < 0.05. Results Forsus and MARA Treatment Effects (T1-T2) During the treatment phase of the Forsus (Figure 3.2), the maxilla moved mesially 1.7 mm and the mandible moved mesially 4.8 mm, resulting in an apical base change of 2.9 mm. The upper molars tipped mesially because the crowns moved mesially 0.7 mm, while the roots moved mesially 0.4 mm. The lower molars tipped distally because crowns and roots moved mesially 1.7 mm and 2.4 mm, respectively; tipping distally 0.6 mm. The total molar correction (ABCH + U6 + L6) was 3.8 mm. The upper incisor distalized 1.1 mm, while the lower incisor moved mesially 1.4 mm. The overjet correction (ABCH + U1 + L1) was 5.6 mm. The upper incisor was retroclined 4.3 degrees and the lower incisors proclined 4.2 degrees. 34 Figure 3.2: Pitchfork treatment changes from T1-T2 in Forsus Sample In the MARA treatment period (Figure 3.3), the maxilla moved mesially 2.8 mm and the mandible moved mesially 5.1 mm, with an apical base change of 2.3 mm. The upper molars tipped distally because the crown was distalized 0.3 mm and the root had no movement. The lower molar crowns and roots moved mesially 0.5 mm, so no tipping was observed. Total molar correction was 3.1 mm. The upper incisor had no movement, while the lower incisor moved mesially 0.2 mm. The overjet correction was 2.6 mm. Both the upper and lower incisors were proclined 1.4 degrees. 35 Figure 3.3: Pitchfork treatment changes from T1-T2 in MARA Sample Between the Forsus and MARA a few findings were statistically significant during T1-T2 including the following: lower incisor angulation, lower molar tipping and lower molar root movement. The lower incisor was proclined 2.8 degrees greater in the Forsus than the MARA. The lower molar had 0.6 mm greater distal tipping in the Forsus than the MARA. Also, the lower molar root movement was 1.9 mm greater in the Forsus than the MARA. The comparisons between the Forsus and MARA during T1-T2 can be seen in Table 3.3. 36 Table 3.3: T1-T2 Pitchfork comparison of Forsus and MARA Forsus Mean 2.9 T1-T2 ABCH (mm) MAX (mm) MAND (mm) U6 Crown (mm) U6 Root (mm) U6 Tipping (mm) L6 Crown (mm) L6 Root (mm) L6 Tipping (mm) 6/6 (mm) U1 (mm) L1 (mm) 1/1 (mm) U1 Angle (°) L1 Angle (°) NS, Not significant *P < 0.05 -1.7 4.8 -0.7 -0.4 -0.3 1.7 2.4 -0.6 3.8 1.1 1.4 5.6 4.3 4.2 SD 1.8 2.1 3.3 2.1 1.8 1.7 1.5 1.8 1.0 2.1 2.3 2.3 3.6 8.9 7.9 MARA Mean SD 2.3 2.2 -2.8 5.1 0.3 0.0 0.3 0.5 0.5 0.0 3.1 0.0 0.2 2.6 -1.4 1.4 2.7 3.8 1.6 1.5 1.5 1.3 1.1 1.4 2.3 1.7 1.9 2.1 7.4 4.2 Significance 0.507 NS 0.600 0.236 0.125 0.335 0.817 0.249 0.012 0.045 0.789 0.095 0.574 0.122 0.534 0.016 NS NS NS NS NS NS * * NS NS NS NS NS * Forsus and MARA Post-Treatment Effects (T2-T3) In the Forsus post-treatment phase (Figure 3.4), the maxilla move distally 0.2 mm, while the mandible moved mesially 0.3 mm, resulting in an apical base change of 0.5 mm. The upper molars tipped mesially because the crowns moved mesially 0.4 mm, while the roots moved distally 0.2 mm. The lower molars tipped distally because crowns and roots moved distally 0.7 mm and 0.2 mm, in that order. The total molar correction was -0.7 mm. The upper incisor moved mesially 0.4 mm and the lower incisor moved mesially 0.2 mm. The overjet correction was 0.3 mm. The upper incisor was proclined 1.7 degrees and the lower incisors proclined 0.7 degrees. 37 Figure 3.4: Pitchfork treatment changes from T2-T3 in Forsus Sample In the MARA sample (Figure 3.5), the maxilla moved mesially 1.1 mm and the mandible moved mesially 3.3 mm, with an overall apical base change of 2.2 mm. The upper molars tipped mesially, with 2.3 mm mesial crown movement and 0.6 mm mesial root movement. The lower molars tipped distally because the crowns moved mesially 0.2 mm, but the roots moved mesially 1.3 mm. There was no molar correction during this period. The upper incisor moved mesially 0.2 mm, while the lower incisor distalized 1.3 mm. The overjet correction was 0.7 mm. The upper incisor was proclined 2.2 degrees and the lower incisors retroclined 1.2 degrees. 38 Figure 3.5: Pitchfork treatment changes from T2-T3 in MARA Sample The statistically significant variables found during T2-T3 between the Forsus and MARA were the treatment duration, apical base change, maxillary and mandibular skeletal movements, upper and lower molar tipping, and lower incisor movement. The post-treatment duration was 13.6 months longer in the MARA than the Forsus. The apical base change was 1.7 mm greater in the MARA than the Forsus. The maxilla moved mesially 1.3 mm greater in the MARA than the Forsus. The mandible moved mesially 3.0 mm greater in the MARA than the Forsus. The upper molars tipped mesially 1.3 mm greater in the MARA than the Forsus and the lower molars tipped distally 0.6 mm greater in the MARA than the Forsus. Finally, the lower incisor movement was distalized 1.5 mm greater in the MARA than the Forsus. The comparisons between the Forsus and MARA during T2-T3 can be seen in Table 3.4. 39 Table 3.4: T2-T3 Pitchfork comparison of Forsus and MARA Forsus Mean T2-T3 ABCH (mm) MAX (mm) MAND (mm) U6 Crown (mm) U6 Root (mm) U6 Tipping (mm) L6 Crown (mm) L6 Root (mm) L6 Tipping (mm) 6/6 (mm) U1 (mm) L1 (mm) 1/1 (mm) U1 Angle (°) L1 Angle (°) NS, Not Significant *P < 0.05 0.5 0.2 0.3 -0.4 0.2 -0.5 -0.7 -0.2 -0.5 -0.7 -0.4 0.2 0.3 -1.7 0.7 SD 1.3 2.0 2.7 1.8 1.7 1.1 1.3 1.8 1.2 1.1 1.3 1.1 1.6 4.7 3.6 MARA Mean 2.2 -1.1 3.3 -2.4 -0.6 -1.8 0.2 1.3 -1.1 0.0 -0.2 -1.3 0.7 -2.2 -1.2 SD 2.8 3.2 5.1 2.4 1.8 2.0 1.8 2.3 2.0 1.6 1.2 2.7 1.8 5.8 5.2 Significance 0.003 0.005 0.001 0.060 0.664 0.005 0.132 0.067 0.021 0.172 0.446 0.001 0.854 0.346 0.150 * * * NS NS * NS NS * NS NS * NS NS NS Forsus and MARA Overall Treatment Effects (T1-T3) The overall treatment effect (Figure 3.6) in the Forsus showed the maxilla moved mesially 1.6 mm and the mandible moved mesially 5.1 mm, resulting in an apical base change of 3.4 mm. The upper molars tipped mesially because the crowns moved mesially 1.2 mm, while the roots moved mesially 0.2 mm. The lower molars tipped distally because the crowns moved mesially 0.9 mm, while the roots moved mesially 2.1 mm. The total molar correction was 3.2 mm. The upper incisor distalized 0.7 mm, while the lower incisor moved mesially 1.5 mm. The overjet correction was 5.8 mm. The upper incisor was retroclined 2.6 degrees and the lower incisors proclined 4.9 degrees. 40 Figure 3.6: Pitchfork treatment changes from T1-T3 in Forsus Sample In the MARA (Figure 3.7), the maxilla moved mesially 3.9 mm and the mandible moved mesially 8.4 mm, with an apical base change of 4.5 mm. The upper molars tipped mesially because the crowns and roots moved mesially 2.1 mm and 0.6 mm, respectively. The lower molars tipped distally because the crowns moved mesially 0.8 mm, while the roots moved mesially 1.9 mm. The total molar correction was 3.1 mm. The upper incisor mesialized 0.2 mm and the lower moved distally 1.1 mm. The overjet correction was 3.2 mm. The upper incisor was proclined 3.6 degrees and the lower incisors proclined 0.2 degrees. 41 Figure 3.7: Pitchfork treatment changes from T1-T3 in MARA Sample The overall treatment effects between the Forsus and the MARA can be seen in Table 3.5. The only variables that were significant in the overall treatment results were the apical base change and the maxillary and mandibular skeletal movements. In the MARA the maxilla and mandible moved mesially significantly more than in the Forsus by 2.3 mm and 3.3 mm, respectively. Also, the MARA sample had 1.1 mm greater apical base change than the Forsus. 42 Table 3.5: T1-T3 Pitchfork comparison of Forsus and MARA T1-T3 ABCH (mm) MAX (mm) MAND (mm) U6 Crown (mm) U6 Root (mm) U6 Tipping (mm) L6 Crown (mm) L6 Root (mm) L6 Tipping (mm) 6/6 (mm) U1 (mm) L1 (mm) 1/1 (mm) U1 Angle (°) L1 Angle (°) NS, Not significant *P <0.05 Forsus Mean 3.4 -1.6 5.1 -1.2 -0.2 -0.9 0.9 2.1 -1.1 3.2 0.7 1.5 5.8 2.6 4.9 SD 1.8 2.2 3.2 2.2 1.4 1.9 2.1 2.6 1.6 2.1 2.6 2.2 3.1 9.4 8.0 MARA Mean 4.5 -3.9 8.4 -2.1 -0.6 -1.5 0.8 1.9 -1.1 3.1 -0.2 -1.1 3.2 -3.6 0.2 SD 4.2 3.0 6.2 2.6 2.1 1.7 2.1 2.2 1.9 2.7 2.1 3.5 2.3 7.3 6.5 Significance 0.003 * 0.017 * 0.005 * 0.542 NS 0.340 NS 0.672 NS 0.745 NS 0.560 NS 0.486 NS 0.273 NS 0.135 NS 0.071 NS 0.262 NS 0.738 NS 0.284 NS Discussion This study was performed to observe the skeletal and dental effects of the Forsus and MARA in Class II malocclusions. This study adds to the existing literature by comparing the two appliances alongside one another. Also the current study expands on previous investigations by evaluating the Forsus and MARA at three timepoints. In the past, the Forsus has only been analyzed at two timepoints. Comparisons of the Forsus and MARA appliance effects from this study to those reported in existing literature can be seen in Table 3.6 and Table 3.7. The subsequent discussion is organized into five sections: maxillary skeletal, mandibular skeletal, maxillary dental, mandibular dental and overall effects. 43 Table 3.6: Comparison of the Forsus appliance effects reported in the literature: Pre-treatment to Post-treatment. Positive sign indicates an improvement in Class II correction (mesial movements in mandible and distal movements in maxilla) Negative sign indicates worsening of Class II malocclusion (distal movements in mandible and mesial movements in maxilla) Author(s) Jones et al.8 Franchi et al.9 Present study ABCH (mm) 2.6 MAX (mm) -1.7 MAND (mm) 4.4 U6 (mm) -1.2 L6 (mm) 1.8 6/6 (mm) 3.2 U1 (mm) -0.7 L1 (mm) 1.2 1/1 (mm) 3.2 U1 (°) -3.7 L1 (°) 6.3 N/A N/A N/A -1.0 2.4 3.4 1.1 2.3 5.4 1.2 6.1 3.4 -1.6 5.1 -1.2 0.9 3.2 0.7 1.5 5.8 2.6 4.9 Table 3.7: Comparison of the MARA appliance effects reported in the literature: Pre-treatment to Post-treatment. Positive sign indicates an improvement in Class II correction (mesial movements in mandible and distal movements in maxilla) Negative sign indicates worsening of Class II malocclusion (distal movements in mandible and mesial movements in maxilla) Author(s) Siara-Olds et al.15 Ghislanzo ni et al.16 Present study ABCH (mm) MAX (mm) MAND (mm) U6 (mm) L6 (mm) 6/6 (mm) U1 (mm) L1 (mm) 1/1 (mm) U1 (°) L1 (°) N/A N/A N/A N/A N/A N/A N/A N/A 0.8 -0.7 0.3 N/A N/A N/A -2.0 3.1 3.9 -1.0 1.4 3.1 1.2 3.3 4.5 -3.9 8.4 -2.1 0.8 3.1 -0.2 -1.1 3.2 -3.6 0.2 Maxillary Skeletal Effects In both the Forsus and MARA the maxilla came forward, which is an expected pattern of normal growth.12 However, the overall treatment effects demonstrated that the Forsus had significantly greater restraint of the maxilla than the MARA. This finding is supported by Franchi et al., who observed that the Forsus had significant restriction on the maxilla. In previous studies, the MARA has also displayed a restriction on the maxilla, however, past investigators showed that this restriction was transient and was not significant long term.15,16 In this study, the greater restraint of the maxilla observed from 44 the Forsus may be due to the simultaneous treatment with fully bonded appliances. In this instance, the Forsus may have more of a “headgear effect” than the MARA because it is not solely focusing its forces on the upper molar. Instead, the Forsus may be able to distalize the entire maxillary dentition because it is tied together giving a greater orthopedic effect. Mandibular Skeletal Effects Similar to the maxilla, the mandible also came forward in both groups, which was anticipated.12 Furthermore, in both samples the mandible had the greatest contribution to the molar correction. In the overall treatment effects, the MARA portrayed a statistically significant increase in mandibular protraction in comparison to the Forsus. In previous investigations of the MARA, different methods have been used to measure mandibular length, so it is difficult to compare the present results to the existing literature. However in a study by Jones et al., who also used the pitchfork analysis for the Forsus, the mandibular skeletal findings were similar. The results of this study may be explained because of the MARA’s greater functional effect with respect to the Forsus. This is probably due to the rigid design of the MARA in comparison to the Forsus. However, the increase in mandibular protraction in the MARA may also be due to the difference in treatment duration between the groups. The overall median treatment time for the Forsus was 26 months while the MARA was 33 months. The difference in time could allow for more mandibular growth in the MARA group versus the Forsus group. 8 45 Maxillary Dental Effects The overall movement of the maxillary dentition was not significant between the MARA and the Forsus, however during the period of post-treatment effects the MARA had significantly greater mesial tipping of the upper molar. This relapse of the upper molar could be due to the greater force placed on the upper molar by the MARA during the treatment period, which caused more tipping rather than bodily movement in molar correction. In general in the MARA and the Forsus groups, the upper molar crowns moved mesially much like previous studies.8,9,16 Similar to the study by Franchi et al., the upper incisors in the present Forsus group were slightly distalized and more upright, but not to a significant amount in comparison to the MARA.9 Mandibular Dental Effects Between the Forsus and the MARA the overall mandibular dental treatment effects were not statistically significant. However, there were significant findings during the treatment (T1-T2) and post-treatment (T2-T3) phase. During the appliance treatment phase, the Forsus group had a significantly greater amount of lower incisor proclination in comparison to the MARA group, which was observed in previous Forsus investigations.8,9,17 However, it is important to recognize that some of the lower incisor proclination may depend on the amount of crowding in each sample. The level of crowding was not recorded and could be a limitation of the study. Also, the lower molar root moved mesially significantly more in the Forsus group than in the MARA group, which suggests more bodily movement of the lower molar in the Forsus group. During the post-treatment phase there was significantly more distal movement of the lower 46 incisors in the MARA in comparison to the Forsus. This could be due to the techniques used by each practitioner after the compliance-free appliance. For instance, the distal movement of the lower incisors in the MARA group during post-treatment phase could have been a result of interproximal reduction used by the practitioner. Also during the post-treatment phase the MARA demonstrated significantly greater lower molar distal tipping in comparison to the Forsus. This may be deceiving because the lower molar crown moved mesially in the MARA group; however, the root moved mesially more than the crown. The overall treatment effect (T1-T3) seen among the two groups was mesial movement of the lower molars. The lower incisors showed more mesial movement and proclination in the Forsus group, but not to a significant degree in comparison to the MARA group. Earlier studies of the Forsus demonstrated greater amounts of lower incisor proclination with 6.1 to 6.3 degrees, in comparison to 4.9 degrees of proclinaton in the present study. This variation between the present study and previous studies may be due to the average amount of overjet and molar correction needed in each sample at the start. Overall Effects The overall treatment effects show that most of the molar correction in both the Forsus and MARA came from skeletal effects. There was 132% and 106% improvement in molar relationship from skeletal effects in the MARA and Forsus groups, respectively. The largest contribution to the skeletal changes came from the mandible in both groups. However, because of a lack of a control sample in this study the contribution of natural growth to this mandibular change cannot be quantified. The dental effects negatively 47 affected the molar relationship, mostly because the maxillary molar moved forward in the Forsus and MARA samples. Conclusions 1) The Forsus and MARA are both acceptable compliance-free appliances for Class II correction. 2) The Forsus has a greater restraint on the maxilla when compared to the MARA. 3) The MARA produces significantly greater forward displacement of the mandible than the Forsus. 4) The Forsus may produce greater lower incisor proclination than the MARA in correction of the overjet. 5) Most of the molar correction is attained from mandibular skeletal effects in both groups. 48 References 1. Kelly JE, Harvey CR. An assessment of the occlusion of the teeth of youths 12-17 years. Vital Health Stat 11. 1977;1–65. 2. Proffit WR, Fields HW Jr, Moray LJ. Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey. Int J Adult Orthodon Orthognath Surg. 1998;13:97–106. 3. McNamara JA Jr. Components of Class II malocclusion in children 8-10 years of age. Angle Orthod. 1981;51:177–202. 4. McSherry PF, Bradley H. Class II correction-reducing patient compliance: a review of the available techniques. J Orthod. 2000;27:219–25. 5. Covell DA Jr, Trammell DW, Boero RP, West R. A cephalometric study of class II Division 1 malocclusions treated with the Jasper Jumper appliance. Angle Orthod. 1999;69:311–20. 6. Alves PFR, Oliveira AG. A comparison of the skeletal, dental, and soft tissue effects caused by Herbst and mandibular protraction appliances in the treatment of mandibular Class II malocclusions. World J Orthod. 2008;9:e1–19. 7. Lai M, McNamara JA Jr. An evaluation of two-phase treatment with the Herbst appliance and preadjusted edgewise therapy. Semin Orthod. 1998;4:46–58. 8. Jones G, Buschang PH, Kim KB, Oliver DR. Class II non-extraction patients treated with the Forsus Fatigue Resistant Device versus intermaxillary elastics. Angle Orthod. 2008;78:332–8. 9. Franchi L, Alvetro L, Giuntini V, Masucci C, Defraia E, Baccetti T. Effectiveness of comprehensive fixed appliance treatment used with the Forsus Fatigue Resistant Device in Class II patients. Angle Orthod. 2011;81:678–83. 10. Cope JB, Buschang PH, Cope DD, Parker J, Blackwood HO 3rd. Quantitative evaluation of craniofacial changes with Jasper Jumper therapy. Angle Orthod. 1994;64:113–22. 11. Pangrazio-Kulbersh V, Berger JL, Chermak DS, Kaczynski R, Simon ES, Haerian A. Treatment effects of the mandibular anterior repositioning appliance on patients with Class II malocclusion. Am J Orthod Dentofacial Orthop. 2003;123:286–95. 12. Proffit WR, Fields HW, Sarver DM. Contemporary Orthodontics. 4th ed. St. Louis: Mosby; 2007. 13. Graber T, Vanarsdall R, Vig K. Orthodontics: Current Principles and Techniques. 4th ed. St. Louis: Mosby; 2005. 49 14. Gönner U, Ozkan V, Jahn E, Toll DE. Effect of the MARA appliance on the position of the lower anteriors in children, adolescents and adults with Class II malocclusion. J Orofac Orthop. 2007;68:397–412. 15. Siara-Olds NJ, Pangrazio-Kulbersh V, Berger J, Bayirli B. Long-term dentoskeletal changes with the Bionator, Herbst, Twin Block, and MARA functional appliances. Angle Orthod. 2010;80:18–29. 16. Ghislanzoni LTH, Toll DE, Defraia E, Baccetti T, Franchi L. Treatment and posttreatment outcomes induced by the Mandibular Advancement Repositioning Appliance; a controlled clinical study. Angle Orthod. 2011;81:684–91. 17. Heinig N, Göz G. Clinical application and effects of the Forsus spring. A study of a new Herbst hybrid. J Orofac Orthop. 2001 Nov;62:436–50. 18. Vogt W. The Forsus Fatigue Resistant Device. J Clin Orthod. 2006;40:368–77; quiz 358. 19. Bos A, Kleverlaan CJ, Hoogstraten J, Prahl-Andersen B, Kuitert R. Comparing subjective and objective measures of headgear compliance. Am J Orthod Dentofacial Orthop. 2007;132:801–5. 20. Franchi L, Mcnamarajr J, Baccetti T. The Cervical Vertebral Maturation (CVM) Method for the Assessment of Optimal Treatment Timing in Dentofacial Orthopedics. Seminars in Orthodontics. 2005;11:119–29. 21. Baccetti T, Franchi L, Mcnamarajr J. The Cervical Vertebral Maturation (CVM) Method for the Assessment of Optimal Treatment Timing in Dentofacial Orthopedics. Seminars in Orthodontics. 2005;11:119–29. 22. Johnston LE. Balancing the books on orthodontic treatment: an integrated analysis of change. Journal of Orthodontics. 1996;23:93–102. 50 Appendix Table A.1: Description of pitchfork analysis variables. These measurements are made relative to the mean functional occlusal plane (MFOP). Positive sign indicates an improvement in Class II correction (mesial movements in mandible and distal movements in maxilla) Negative sign indicates worsening of Class II malocclusion (distal movements in mandible and mesial movements in maxilla)22 Variable Skeletal Change Abbreviation ABCH Maxilla Max Mandible Mand Upper Molar U6 Lower Molar L6 Molar Relation 6/6 Upper Incisor U1 Lower Incisor L1 Overjet 1/1 51 Definition The accumulation of maxillary and mandibular growth relative to cranial base, ABCH= Max + Mand Maxillary displacement relative to cranial base Mandibular displacement relative to cranial base Upper first molar displacement relative to basal bone, measurement is taken at the mesial contact point Lower first molar displacement relative to basal bone, measurement is taken at the mesial contact point The change in molar relationship is determined by adding the ABCH to the upper and lower molar movements, ABCH + U6 + L6 = 6/6 Upper incisor displacement relative to basal bone, measurement is taken at the incisal edge Lower incisor displacement relative to basal bone, measurement is taken at the incisal edge The change in overjet is determined by adding the ABCH to the upper and lower incisor movements, ABCH + U1 + L1 = 1/1 Vita Auctoris Shereen Azizollahi was born on September 6, 1983 in Los Angeles, California to Arsalan Azizollahi and Nasrin Azizollahi. She is the younger of two children. She grew up in Irvine, California and graduated from University High School in June of 2001. She attended the University of California Los Angeles for her undergraduate studies where she received a Bachelor in Science in Biology in 2005. She attended the University of Southern California where she earned her Doctorate of Dental Surgery degree in 2009. Subsequently, she began the orthodontic residency program at Saint Louis University where she expects to receive a Master of Science in Dentistry (Research) degree. During her orthodontic residency she married Jonathan Falakassa in June 2011. Upon graduation, she will move to Miami, Florida to begin her orthodontic career. 52