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ORTHOdontics PGI/II ____________________________________________________________________________________________________________ _________ PEDIATRIC ORTHODONTICS INCLUDES PRINCIPLES AND APPLICATIONS OF: EARLY TREATMENT WITH FOCUS ON CLASS II, DIVISION 1 MALOCCLUSION ____________________________________________________________________________________________________________ _________ FACULTY: Joseph Ghafari , DMD. Goals: This series of lectures should enable the resident to: 1. Define early treatment in reference to chronological and biological ages. 2. Understand the normal development of the occlusion and how to intercept interferences with that development. 3. Understand the potential and limitations of early treatment of various malocclusions. 4. Understand the principles of diagnosis and treatment planning of occlusal problems as well as the types of mechanotherapy that can be utilized for their correction. Objectives: The resident should know: 1. The interferences that may affect normal development of the dentition in its arch and occlusal components. 2. The types of sagittal (Class I anterior protrusion, Class II, Class III -pseudo vs. true) vertical (deep bite, open bite) and transverse (midline deviation, posterior crossbite) that may benefit from early treatment. 3. When to prevent, intercept, or correct a developing problem, and determine the limitations of intervention. 4. Know the consequence of early treatment or delayed treatment. 5. The evidence available for modalities of early treatment and its timing in the primary, transitional (early/mid versus late), and permanent dentition. 6. The findings from available key clinical trials on Class II division 1 malocclusion. 7. The mechanotherapy involved, with in dept-knowledge of selected modalities. 8. How habits help develop and/or maintain certain malocclusions, and ways to manage these habits. ____________________________________________________________________________________________________________ _________ COURSE DURATION AND SCOPE: This course is part of the Early Treatment series that includes research studies on Class II treatment. The course is scheduled in the Spring of the first year and/or the Fall of the second year. It is given at a 2-hour session on a weekly basis for at least 5 sessions. A prerequisite to this course is the course on Development of the Dentition. POLICY ON EXAMINATIONS: At least 2 biannual examinations (progress and final) are given for all courses, if a course spans the entire year. If classes terminate before the end of a semester, the final examination is given at the semi-annual examination that is closest to the end of the course, unless the course director schedules the final examination earlier. During a course, any number of progress tests or assignments may be given. Their cumulative weight in proportion to the final grade may not exceed 50%. PEDIATRIC ORTHODONTICS ____________________________________________________________________________________________________________ _________ SUMMARY OUTLINE INTRODUCTION - - CONCEPTS ON MODALITIES OF TREATMENT AND OF TREATMENT TIMING - CLINICAL TRIALS - GENERAL TRENDS AND INDIVIDUAL VARIATIONS - IMPLICATIONS OF RESEARCH FINDINGS ON OF CLASS II AND CLASS I TREATMENT MALOCCLUSIONS ____________________________________________________________________________________________________________ _________ COURSE OUTLINE Introduction Goals of early treatment of malocclusion - Prevent the development of malocclusion: avoid potential interferences with normal development - Intercept the development of malocclusion: remove existing interferences [already developing malocclusion]. - Correct an already developed malocclusion: before the cessation of facial growth Underlying Assumptions - Dealing with bite problems at one or various times during a child’s growth: Issue of timing treatment -Knowledge of normal growth of jaws (relation to somatic growth), teeth, and developing relation between occlusion and jaws -Coordinating time of treatment with optimal time of growth: Issue of growth prediction. 1. EARLY ORTHODONTIC TREATMENT OF OCCLUSAL PROBLEMS CONCEPTS ON MODALITIES AND TIMING OF TREATMENT 1. MANAGEMENT OF SAGITTAL OCCLUSAL PROBLEMS A. Class I, anterior protrusion Condition Treatment B. Distoclusions a. Class II, anterior protrusion (Class II, Division 1). Condition: -association with oral habits -existence of an underlying skeletal problem. In this instance, early treatment is almost invariably the initial phase in a series of two or more therapeutic phases ending with the use of full or partial fixed orthdontic appliances in the permanent dentition. -skeletal and dentoalveolar components Treatment Whether the malocclusion is of a skeletal, dento-alveolar, or combined origin, treatment approaches have relied on similar rationales, perhaps underlying a practical inability to treat a distoclusion with complete control of its skeletal and neuromuscular components while the dental system is comparatively easier to manage. -mechanotherapy: depending on whether the maxilla alone, or both jaws, are targeted: (i) head gear, attached to the molars or to a removable appliance (Thurow appliance). Numerous types of headgear: vary in direction of extraoral traction relative to occlusal plane, that is, relative to the center of resistance of the anchoring teeth or group of teeth. Three major types: 1. cervical pull with distal and vertical extrusive force components and a general direction of pull below the occlusal plane; 2. high pull with distal and intrusive force components and a direction of pull above the occlusal plane; and 3. straight pull headgear with a distal retractive force moving maxillary teeth along the occlusal plane. Distal movement of molars is easier with a cervical pull headgear because of the lesser resistance to molar extrusion than intrusion. Two major effects of headgear therapy: are the direct influence on maxillary growth, and the indirect effect on mandibular position and, therefore, on the relationship between maxillary and mandibular structures. (ii) ACCO (Acrylic Cervical Occipital Anchorage) or similarly designed (Cetlin) appliances: distalize posterior teeth into neutroclusion and create space for later reduction of the anterior protrusion. (iii) functional appliance. Many functional appliances have been described, starting with the activator and its modifications and including the bionator, function regulator or Frankel, and the Herbst appliances (see separate course on Functional Appliances). Dentoalveolar changes widely documented. Controversies on mode of action revolve mainly around their role in stimulating mandibular growth. Following possibilities advanced: 1. the mandible surpasses its growth potential; 2. mandibular growth is accelerated; These hypotheses assume that the individual growth potential can be predicted within reasonable accuracy. 3. mandible is merely positioned forward and subsequent growth, if sufficient, adapts (“catches up”) to this position. This hypothesis assumes that (a) occlusal interdigitation plays an important role in maintaining the mandible in the forward position, and (b) the most important effect of a functional appliance is the distal force on the maxillary complex.This effect is achieved through the forces transferred to the maxillary teeth and bone by the appliance. (iv) Combinations of headgear and functional appliances. There is an empirical tendency to maximize the response of each jaw, regardless of the origin of the problem. This tendency is probably due tor inability to accurately predict and influence growth, particularly in mandible. b. Class II, Division 2 Condition: -original description by EH Angle. -variations and classifications (Jarabak: four types including Class I, division 2; Ghafari and Street: four basic types of Class II, Division 2 malocclusion, based on the inclination of the maxillary incisors, the mandibular plane, and the interincisal angle.). Treatment -distoclusion: with headgear, ACCO, or combined therapy if distal movement of maxillary molars is needed. A functional appliance, when indicated, often requires aligning the maxillary incisors to allow an adequate mandibular forward positioning. -overbite: interception might require early extraction of the maxillary primary canines for orthodontic or self-alignment of permanent lateral incisors, with inhibition of vertical drift of the permanent central incisors. Early treatment of a Class II, Division 2 malocclusion should prevent a worsening of the anterior deep bite which, in severe cases, may be accompanied by an inhibited vertical drift of the posterior teeth and an accentuation of the chin (“chin button”). c. Observations on the evaluation of the early treatment of distoclusions Factors influencing evaluation of early treatment summarized as differences in populations and appliances, and differences in and/or inadequacies of methodology used in clinical studies. 1. Early treatment of distoclusions mostly transforms a Class II malocclusion to a Class I malocclusion, not a Class I normal occlusion. 2. Criteria to note success often lacking, for success must be evaluated at different levels within the same occlusion. Often, correction of molar occlusion temporally separate from achievement of canine neutroclusion and/or overjet. 3. Malocclusion must be clearly defined, to eliminate any “noise” in the selection process of a study’s population. (Class II malocclusion refers to Class II molar relationship regardless of the canine occlusion? Existence of a skeletal problem?). C. Anterior Crossbite a. Dental crossbite Condition usually affects one or two incisors in otherwise normal occlusion. Treatment: correct inclination of involved tooth/teeth; two essential considerations: space requirements and overbite. Prerequisite: provide space for alignment. -mechanotherapy: removable plates with finger springs; fixed and removable inclined planes. b. Dento-alveolar crossbite Condition involves crossbite of a group of teeth, usually all four incisors, in a seemingly Class III or “super Class I” occlusion (also known as a pseudo-Class III or functional anterior crossbite). Treatment considerations include proper positioning of affected teeth, and disocclusion of anterior teeth if deep overbite. Early correction of this crossbite is important to prevent its stabilization in the permanent dentition and avoid hindrance of anterior maxillary alveolar growth. -mechanotherapy: fixed orthodontic appliances; inclined planes; “sagittal” removable appliances (procline maxillary anterior teeth by periodic activation of jackscrew built into plate); functional appliances (effect seems limited; chin cup (success seems contingent on severity of crossbite, depth of the bite, and patient’s cooperation. d. Anterior crossbite with underlying skeletal discrepancy. Condition: “True” Class III malocclusion: rarely, if ever, resolved by orthodontic means, and in most cases surgical correction is required, normally after or towards the end of mandibular growth (skeletal ages of 16-18 years in females, 18-20 years in males). Treatment: Treatment approaches include the extended use of a chincup, the “Delaire mask” or reverse headgear, or both. Major problem with early treatment: ability to forecast malocclusion’s development. Yet early treatment may reduce the severity of the malocclusion by minimizing associated problems such as crowding of the maxillary arch. If left uncorrected, problem may have to be treated later by tooth extractions (usually premolars) that contract a maxillary arch already constricted relative to the mandibular arch. The use of a palatal expander is often indicated, after accurate diagnosis of transverse occlusal relationships is necessary. 2. MANAGEMENT OF VERTICAL OCCLUSAL PROBLEMS A. Deep overbite Condition: dentoalveolar. Treatment: correction leads to an increased overjet; aims at enhancing eruption of posterior teeth, while maintaining height of incisors, especially if underlying skeletal hypodivergency. -mechanotherapy: a-removable appliance with anterior bite plate; retraction of incisors to reduce overjet with same appliance (stretching elastics against incisors). b-fixed appliances: partial banding/bonding of permanent first molars and incisors; “intrusive” arch promotes extrusion of molars (easier achieved) and intrusion of the incisors (consider increasing posterior anchorage e.g. with palatal bar or headgear, particularly when tendency to skeletal vertical hyperdivergency. True intrusion is difficult to achieve; however, in a growing individual, stabilization of the incisors is considered a relative intrusion since their vertical movement is impeded relative to the other teeth. B. Anterior open bite Condition: usually associated with a habit (digit sucking or tongue thrust). Treatment: 1- correct habit 2- treatment rationales: -increase overbite (“close” bite) by favoring extrusion or proper eruption of anterior teeth. -stabilize or depress posterior teeth (particularly in skeletal hyperdivergent patterns). -mechanotherapy: appliance, such as tongue crib, may eliminate associated habit while effecting bite closure; fixed appliances; high-pull headgear; bite block (hard – acrylic- or soft –rubber); incorporated magnets; vertical pull chin cup (no definite evidence). -special consideration for skeletal hyperdivergency: blocked airways must be examined may need removal. In many patients with underlying skeletal problems, early treatment with orthodontic appliances is compensatory at best, and surgical correction would be considered later. If early therapy is successful, retention of results through the end of active facial growth is indicated. 3. MANAGEMENT OF TRANSVERSE OCCLUSAL PROBLEMS A. Posterior crossbite a. A single tooth crossbite -Condition: buccal or lingual, involves a tipping of the affected maxillary or mandibular tooth. -Treatment: correct inclination of malaligned maxillary, mandibular or both teeth (not indicated for a single primary molar in crossbite). -mechanotherapy: crosssbite elastics; removable appliance with finger spring or jack screw; fixed appliances. b. posterior segment of an arch is in crossbite. -Condition: unilateral and bilateral crossbites. -if unilateral: differentiate between true or anatomic (occlusion similar in IC=RC) unilateral crossbite and functional crossbite (mandible shifts laterally to side of crossbite from IC to RC); therefore bilateral component in RC, an indication for bilateral treatment). -Treatment: depending on severity dental buccal tipping, dentoalveolar, or palatal expansion. -mechanotherapy: Porter or W appliance, Quad helix, a removable plate with expansion jack screw, fixed appliances with a springor a jack screw ( Haas or Hyrax types), expanded archwires in banded orthodontic appliance. Uncorrected, the mandibular lateral shift may become permanent: an asymmetry of the corpus and the condyle might follow (not definitively proven). The shift often is caused by an occlusal interference of the primary canines for a more convenient occlusion with the posterior crossbite. Reduction of the occlusal interference may eliminate the mandibular deviation and should be attempted prior to the expansion, particularly in cases of mild constriction of the maxillary arch. c. Bilateral crossbites can also be anatomic (CO=CR) or have an additional functional component (mandibular shift to the side of the crossbite). But differentiation is academic since bilateral expansion required in both cases. d. posterior crossbite where maxillary molars are in full buccal position relative to the mandibular opposing teeth (Brodie syndrome). -Condition: Rare and difficult to manage. -Treatment: often implies constricting maxillary arch, rather than expanding mandibular arch, but sometimes both. Constriction of the maxillary arch may require a later extraction of permanent teeth (usually premolars), or in case of distoclusion, additional space may be provided by distal movement of the molars. B. Midline deviation Between the dental arches are discussed. -diagnosis: establish whether a skeletal deviation exists, if so, whether it is true or functional. Functional deviation associated with posterior crossbite and corrected simultaneously. If true skeletal midline discrepancies, rule out any pathology within the mandible or of the condyles. 4- CONTROVERSIES ON TIMING TREATMENT Opinions of orthodontists on early treatment vary widely: 1- start therapy as early as the developing malocclusion is identified as natural forces brought to normal function. 2no advantage to be gained. 3justified if orthodontist can achieve either definite interception of malocclusion or meaningful reduction of severity to affect outcome and/or length of later complete correction. Problem: predicting facial development. Insofar as the individual patient deviates significantly from the average, success can be limited. Limitations increase with malocclusions involving skeletal discrepancies. Timing of treatment: Value of early treatment versus waiting until permanent dentition erupted demonstrated. Controversy as to how early. Primary dentition: controversial, no evidence, but demonstrated for limited types of malocclusion. Mixed dentition: two-phase treatment versus one stage two-phase-treatment. See clinical trials section. 2. CLINICAL TRIALS: DESIGN, SET-UP, AND FINDINGS 1. DESIGN OF TRIALS 2. FINDINGS -Retrospective versus retrospective. -Inclusion and exclusion criteria -Protocol -Facial changes. -Occlusion -Cephalometric changes -Conclusions on modalities of treatment -Conclusions on timing of treatment Findings from a prospective randomized clinical trial indicated that treatment of Class II, division 1 malocclusion was as effective in late childhood as in midchildhood. Optimal timing of treatment would be in the late mixed dentition before the loss of the primary second molars. Practical implications of the findings are emphasized with clinical illustrations, specifically the effect on treatment timing of saving the leeway space, and taking advantage of differential growth between the jaws. General guidelines are weighed in consideration of the concept of early treatment as one-phase treatment, and whether this concept can be generalized in view of epidemiologic findings and individual variation. 3. GENERAL TRENDS AND INDIVIDUAL VARIATIONS IMPLICATIONS OF RESEARCH FINDINGS ON TREATMENT OF CLASS II AND CLASS I MALOCCLUSIONS 1. GENERAL TREND -Treat in late mixed dentition to take advantage of growth events: -dental: E space Loss of second primary molars: an indicator of space loss and potential modification in molar occlusion -skeletal: growth (before adolescent spurt). Adolescent growth spurt: an indicator of the beginning of decrease in the rate of growth (not total cessation, but on average, what is left is comparatively less in amount and predictability) 2. EARLIER INTERVENTION 3. EPIDEMIOLOGIC FINDINGS -Occlusal and developmental conditions requiring earlier intervention: -functional crossbite -trauma (related to severe overjet) -psychosocial development (related to severe overjet) -early loss of primary teeth -discrepancy between requirements of dental age and skeletal age - support trend in majority of patients 4. MANAGEMENT OF HABITS ASSOCIATED WITH OCCLUSAL PROBLEMS 1. 2. Relation of vertical occlusal problems to sagittal (and transverse) problems. Differentiation between skeletal, dentoalveolar and dental deep or open bite. 1- TONGUE THRUST A. Swallow Patterns a. Infantile swallow pattern B b. Transitional swallow pattern c. Adult swallow pattern Types of tongue thrust a. b. c. Subtelny' s classification - (on basis of diagnosis) Moyer' s classification - (on basis of etiology) Ghafari' s classification- (on basis of treatment) Analysis by Proffit et al. (1978, 1993) a. Transitional swallow patterns from infantile through adult swallow pattern. b. Tongue pressures in speech and swallowing not significantly different in tongue thrusters and non-thrusters c. In patients with incisor protrusion, the amount of anterior pressure is inversely related to the amount of anterior protrusion. d. Tongue pressures directed horizontally against the teeth by tongue thrusters are not sufficient in force or duration to push teeth into a new position. e. Orthognathic surgery patients adapt tongue pressure and contact patterns to the environment created, usually within a one year span. f. Tongue and lip pressures never balance during swallowing and tongue pressures are always several times higher (Lear and Moorrees, 1969). g. Tongue and lip pressures over time do not balance out to create an "equilibrium". h. The functional activities of the tongue are not important determinants in tooth position, but an anterior resting tongue position and associated vertical pressure against the anterior teeth can contribute to or maintain an anterior open-bite malocclusion (Proffit and Mason). C. D. Malocclusions associated with tongue thrust E. Treatment 2- THUMB (FINGER) SUCKING 1. Prevalence of malocclusion significantly higher in children with sucking habits than in those without the habits at 3 and 12 years of age (Popovitch and Thompson, A,. J. Orthod., 1973). 2. In children in whom thumb or finger sucking ceased before the age of 6 years, prevalence of malocclusion was not higher than with children with no history of sucking habits (op. cit.) 3. Malocclusions associated with digit sucking 4. Methods for controlling the habit: a. Prevention- behavioral approach b. Positive reinforcement c. Aversive conditioning techniques 3- RELATION BETWEEN DIGIT SUCKING AND TONGUE THRUST REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. Freeman JD. Preventive and interceptive orthodontics: A clinical review and the results of a clinical study. J Prev Dent 1977; 4:7-23. Ghafari J. Management of oral habits related to occlusal problems- In preparation/press. Proffit WR. Diagnosis of malocclusion, in Contemporary Orthodontics. St. Louis, The CV Mosby Co., 1992. Bowden DEJ. Theoretical considerations of headgear therapy: literature review. Brit J Orthod 1978;5:145-52. Baumrind S, Molthen R, West EE, Miller SM. Mandibular plane changes during maxillary retraction. Am J Orthod 1978; 74:32-40. Melsen B. Effects of cervical anchorage during and after treatment: an implant study. Am J Orthod 1978; 73: 526-40. Bratcher HJ, Muhl ZF, Randolph RG. Clinical measurement of distally directed headgear loading. Am J Orthod 1985; 88:125-32. Graber TM, Newmann B. Removable Orthodontic Appliances. Philadelphia, WB Saunders Co, 1985. Graber TM. Physiologic Principles of Functional Appliances. St. Louis, The C.V. Mosby Co., 1985. Mills JRE. Clinical control of craniofacial growth: a skeptic’s viewpoint. In Clinical Alteration of the Growing Face, Monograph 14, Craniofacial Growth Series, Center for Human Growth and Development. The Univ. of Michigan, Ann Arbor, 1983. McNamara JA Jr., Bookstein FL, Shaughnessy TG. Skeletal and dental changes following functional regulator therapy on Class II patients. Am J Orthod 1985; 88:91-110. Ghafari J, Degroote C. 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Effects of chincap force on the timing and amount of mandibular growth associated with anterior reversed occlusion (Class III malocclusion) during puberty. Am J Orthod 1986; 90:454-63. 41. Burstone CJ. Application of bioengineering to clinical orthodontics. In Graber TM, Swain BF (eds): Orthodontics, Current Principles and Techniques. St. Louis, The CV Mosby Co., 1985, pp 193-227. 42. Subtelny JD, Musgrave KS. Open bite treatment: The why of success or failure. In Cook JT (ed):Trans. 3rd Int. Orthod Cong, London, Crosby Lockwood Staples, 1975, pp 432-445. 43. Altuna G, Woodside DG. Response of the midface to treatment with increased vertical occlusal forces. Angle Orthod 1985; 55:251-63. 44. Dellinger. A clinical assessment of active vertical corrector Am J Orthod 1986;89(5):428-436 45. Kaira V, Burstone CJ, Nanda R. Effects of a fixed magnetic appliance on the dentofacial complex. Am J Orthod Dentofacial Orthoped 1989; 95: 467–478. 46. Pearson LE: Vertical control in fully-banded orthodontic treatment. Angle Orthod 1986; : 205-24. 47. Chaconas SJ. Preventive orthodontics: When and why. J Prev Dent 1978; 53:30-5. 48. Bell RA. A review of maxillary expansion in relation to rate of expansion and patient’s age. Am J Orthod 1982; 81:32-6. 49. Hicks EP. Slow maxillary expansion. A clinical study of the skeletal versus dental response to low magnitude force. Am J Orthod 1978; 73:121-41. 50. Timms DJ. Rapid Maxillary Expansion. Chicago, Quintessence Books, 1981. 51. Bishara SE, Staley RN. Maxillary expansion: clinical implications.Am J Orthod 1987; 91:3-14. 52. Kutin G, Hawes RR. Posterior cross-bites in the deciduous and mixed dentitions. Am J Orthod 1969; 56:491-504. 53. Kantomaa T. Correction of unilateral crossbite in the deciduous dentition. Eur J Orthod 1986; 8:80-3. 54. Thilander B, Wahlund S, Lennartsson B. The effect of early interceptive treatment in children with posterior crossbite. 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Nance HN. The limitations of orthodontic treatment. Am J Orthod Oral Surg 1947; 33:177-223, 253, 301. 64. Terry HK. Cases indicating early treatment. Am J Orthod 1955; 41:279-90. 65. Terwilliger KF. Treatment in the mixed dentition. Angle Orthod 1950; 20:109-113. 66. Murray RB. Treatment planning and therapy in the mixed dentition. Am J Orthod 1963; 49:641-57. 67. Dewel BF. Objectives of mixed dentition treatment in orthodontics. Am J Orthod 1964; 50:504-20. 68. Graber TM, Chung DDB, Aoba JT. Dentofacial orthopedics versus orthodontics. J Am Dent Assoc 1967; 75: 1145-66. 69. Ackerman JL, Proffit WR. Preventive and interceptive orthodontics: A strong theory proves weak in practice. Angle Orthod 1980; 50:75-87. 70. De Baets J, Joho JP, Schatz JP. The Geneva Plate-Headgear appliance. Early treatment of severe Class II open-bite cases. 62nd Congress Eur Orthod Soc p 87 (Abst), 1986. 71. Björk A. Timing of interceptive orthodontic measures based on stages of maturation. Trans Eur Orthod Soc 61-74, 1972. 72. Ghafari J. Early treatment of dental arch problems. I. Space maintenance, space gaining. Quintessence Int 1986; 17:423-32. 73 . Ghafari J. Early treatment of dental arch problems. II. Guidance in alignment and occlusion. Quintessence Int 1986; 17:489-95. 74. Moyers RE. Handbook of Orthodontics, 4th edition 1988-Chicago, Yearbook Publ. Co. ADDITIONAL REFERENCES 1. 2. 3. 4. Ghafari J. Emerging paradigms in orthodontics- An essay. Am J Orthod Dentofacial Orthop. 1997;111:573-80. . Cortella S, Shofer F, Ghafari J. Transverse development of the jaws- Norms for the posteroanterior cephalometric analysis. Am J Orthod Dentofacial Orthop. 1997;112:519-22. Ghafari J, Shofer FS, Jacobsson-Hunt U., Markowitz DL, Laster LL. Headgear versus function regulator in the early treatment of Class II, Division 1 malocclusion. Am J Orthod Dentofacial Orthop 1998;113:51-61. Ghafari J, Street KW. Dental development in children with Class II, Division 2 malocclusion- Four types of the malocclusion defined. In Biological Mechanisms of Tooth Eruption, Resorption, and Replacement by Implants, Z. Davidovitch, J. Mah (eds.). The Harvard Society for the Advancement of Orthodontics. 589-596, 1998. (Primary research data presented). 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. Ghafari J, King GJ, Tulloch JFC. Early treatment of Class II, Division 1 malocclusion: Comparison of alternative treatment modalities. Clin Orthod Research. 1998; 1:107-117. Ghafari J. Timing the early treatment of Class II, Division 1 Malocclusion: Clinical and research considerations. Clin Orthod and Res. 1998;1:118-129. Ghafari J. The role of developmental and occlusal conditions in timing orthodontic treatment. Alpha Omegan. 1999; 92:28-35. McDonald JL, Shofer F S, Ghafari J. Effect of molar rotation on arch length. Clin Orthod and Res. 2001; 4:79-85. Ashmore JL, Kurland BF, King GJ, Wheeler TT, Ghafari J, Ramsay DS. A three-dimensional analysis of molar movement during headgear treatment. American Journal of Orthodontics and Dentofacial Orthopedics. 2002; 121:18-30. Ghafari J. Therapeutic and developmental maxillary orthopedics: Evaluation of effects and limitations. In Biological Mechanisms of Tooth Eruption, Resorption, and Replacement by Implants, Z. Davidovitch, J. Mah (eds.). The Harvard Society for the Advancement of Orthodontics. 167-181, 2004. Efstratiadis S, Baumrind S, Shofer F, Jacobsson-Hunt U, Laster L, Ghafari J. Evaluation of class II treatment by cephalometric regional superimpositions versus conventional measurements. Am J Orthod Dentofacial Orthop 2005; 128:607-18. Chalala CY., Ghafari JG. Variability in the sequence and timing of emergence of primary and permanent teeth: discrepancies in norms and clinical significance. Lebanese Dent J 2005; 42:59-63. Ghafari J, Jacobsson-Hunt U., Markowitz D., Shofer F.S., Laster L.L. Changes of arch width in the early treatment of Class II, Division 1 malocclusions. A J Orthod Dentofacial Orthop 1994:106:496502. Ghafari J, Jacobsson-Hunt U, Markowitz D, Shofer FS, Katz SH, Laster LL. Dentitional changes and somatic growth in the early treatment of Class II, Division 1 Malocclusions. In Orthodontic Treatment: Outcome and Effectiveness, J. A. McNamara, Jr. (editor), the Craniofacial Growth Series, Center for Growth and Development, Ann Arbor, Michigan. 139-161, 1995. Ghafari J, Markowitz DL, Jacobsson-Hunt U, Shofer FS, Katz SH, Laster LL. Somatic growth and dentitional changes during orthodontic treatment of prepubertal children. Humanbiologia Budapestinensis 1994;25:69-75. Ghafari J, Shofer FS, Markowitz DL, Jacobsson-Hunt U, Nicozisis J, Katz SH, Laster LL. The role of dental development and somatic growth in timing orthodontic treatment. In: Biological Mechanisms of Tooth Movement and Craniofacial Adaptation, Z. Davidovitch (ed.). The Harvard Society for the Advancement of Orthodontics. 441-448, 1996. (*)