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Appliance Therapy The occlusal guard: a simplified technique for fabrication and equilibration John Antonelli, DDS, MS n Timothy L. Hottel, DDS, MS, MBA n Sharon C. Siegel, DDS, MS n Robert Brandt, DDS, MS Gladston Silva, DDS, DMD Hard occlusal guards have been used effectively to treat myofacial pain originating from parafunctional activities. They can also protect the natural dentition when it opposes porcelain restorations, help to evaluate changes in occlusal vertical dimension during full mouth rehabilitation, minimize further tooth loss in patients with abfraction lesions, and redirect occlusal loads more favorably onto dental implant-supported I t is generally agreed that hard occlusal guards play an important role in the treatment of temporomandibular disorders (TMD), particularly where myofacial pain is a prominent symptom.1-6 Occlusal guards are also useful in the treatment of nocturnal bruxism, clenching, and the associated occlusal-incisal attrition seen in adults and children.6,7 This article does not propose to address the role that apnea, GERD, and other sleep disorders may have in the etiology of parafunction. The goal of this article is to teach the reader how to construct a customized occlusal guard for a patient with myofacial pain initiated by deflective occlusal interferences. The authors recognize that there are numerous appliances used to treat various classifications of TMD, which might involve intra-articular problems, derangement of the temporomandibular joint, arthritis, trauma, disk derangements, degenerative joint disease, inflammatory disorders, and others. A comprehensive treatment of TMD, however, is beyond the scope of this article; therefore, the authors have, by design, chosen to limit the discussion to treating masticatory muscle disorders, protecting dental restorations, evaluating lost occlusal vertical dimension (OVD) non-invasively with an occlusal guard, limiting the advance of abfraction lesions, and protecting dental implants. A well-constructed appliance allows the condyles to seat in their most anterior superior position [that is, centric relation (CR)], provides anterior disclusion (canine guidance), provides even and simultaneous incisal and posterior occlusal point contacts with opposing functional cusps, prostheses. A simplified technique is described to fabricate a properly designed wax model of an occlusal guard that can be processed in acrylic in the same manner used to construct a complete denture. Received: March 15, 2012 Revised: August 2, 2012 Accepted: September 24, 2012 and prevents posterior contact in all excursive movements. The guard should not have any occlusal or cuspal indentations into which opposing teeth can lock and exert heavy lateral or thrusting forces; a smooth occlusal surface removes sensory feedback from interfering with tooth contacts and allows elevator muscles to move the mandible so that the condyles can slide posteriorly and up the slopes of the eminentiae for complete seating in CR. If the condyles are healthy and can accept occlusal loading, then an appliance that permits the condyles to seat during a clench will eliminate lateral pterygoid resistance to the masseter and temporalis muscles, and provide relief from myofacial pain. Dawson refers to this design as permissive.8 Permissive guards are also referred to as muscle deprogrammers. A proper occlusal guard should be made of highly polished heat-polymerized acrylic resin. In the authors’ experience, maxillary guards are preferred as they are better tolerated, more stable, avoid crowding the tongue, and achieve occlusal contact with all opposing teeth regardless of the maxillomandibular relationship. Obtaining proper anterior contact and incisal guidance with a mandibular appliance can be difficult in patients with Class II and III maxillomandibular relationships.9 Materials and methods Constructing a hard occlusal guard is relatively uncomplicated. This article describes a simple technique that uses few materials to process a wax model in acrylic according to the same technique used in the construction of complete dentures. www.agd.org The first step in this technique is to obtain a set of irreversible hydrocolloid (alginate) impressions that are free of voids. A snap removal from the mouth is recommended, as rocking upon removal causes distortion and tearing, and leads to an ill-fitting appliance. Pour impressions immediately into Resin Rock (Whip Mix Corporation). Resin Rock is ideal for producing accurate casts as it provides 2 major advantages: it is a resin-fortified die stone that is more abrasion-resistant than other gypsum products, and it exhibits less setting expansion (0.08%) than conventional model stones (setting expansion range 0.9% to 0.16%). Use a facebow transfer to relate the maxillary cast to a semi-adjustable articulator. Arbitrary hand articulation and subsequent mounting of casts on an articulator should be avoided as they generally result in significant occlusal discrepancies and the need for additional chairside adjustments of the appliance at the delivery appointment. Chairside adjustments can be minimized further by making a CR bite record to mount the mandibular cast. To record CR, soften a piece of extra hard pink base plate wax (Beauty Pink Wax, Miltex, Inc.) and then cut to the shape of the maxillary arch. Place the softened wax over the maxillary teeth to index the wax (that is, record indentations of the cusps). Remove and chill the wax and then replace over the teeth and check for stability. Attach two thicknesses of green Aluwax (Aluwax Dental Products Co.) to the premolar-molar regions of the pink wax. Soften the Aluwax and place the indexed wax intraorally to record the General Dentistry May/June 2013 49 Appliance Therapy The occlusal guard: a simplified technique for fabrication and equilibration Fig. 1. Frontal view of the maxillary cast with soft wax. The soft wax adapts accurately to the buccal, lingual, and occlusal surfaces of the cast. Fig. 2. Occlusal view of the maxillary cast with soft wax. A thin articulating ribbon—blue side facing the wax—was placed on the wax to record all occlusal contacts in shallow depressions. Fig. 4. Occlusal view of the maxillary cast with soft wax. Broad mandibular laterotrusive canine contacting surfaces (red) in wax were narrowed prior to investing and processing the guard. Fig. 5. Side view of the articulated casts. Wax has been shaped and smoothed to develop an anterior ramp and canine eminences. bite. Remove the wax record after approximately 45 seconds and chill in cold water prior to articulating the mandibular cast. Verify that the articulated casts conform identically to the patient’s CR bite. The next step is to outline in pencil on the maxillary cast the peripheral extent of the appliance. The lingual border should extend approximately 10 mm apical to the free gingival margins. For adequate retention of the guard, the labial border should terminate between the incisal and middle thirds of the anterior teeth; the border around posterior teeth may be slightly longer. Survey the maxillary cast to detect deep undercuts that could prevent seating of the appliance in the mouth; undercuts may be blocked out by applying stone or plaster directly to the cast. Block-out procedures may be omitted if undercuts or embrasures are minimal and subsequent interferences to seating the guard can be removed at the time of insertion. With both casts on the articulator, eccentric guidance and the thickness of the guard are best developed by using an anterior guide pin in contact with the patient’s previously constructed custom incisal guidance table. If a custom guidance table is not available, then a mechanical incisal guidance table may be inserted on the articulator and set flat initially. Open the occlusal vertical dimension of the articulator by extending the incisal pin downward. An interocclusal space of approximately 1.5 to 2.0 mm should exist in the molar region of 50 May/June 2013 General Dentistry www.agd.org Fig. 3. Close-up occlusal view of the maxillary cast after a new piece of articulating ribbon—red side facing wax—was placed over the wax. A working side interference (arrow) was detected. the casts; this should be approximately the same OVD as the one at which the wax CR record was made and should provide sufficient room for the anticipated thickness of the appliance. A pin extension of approximately 5.0 to 6.0 mm is in the range of opening for this purpose. Check the clearance between opposing casts during protrusive movement. If there is less than 1.5 mm clearance, then increase it by tilting the mechanical guidance table. Raise the wings of the mechanical guidance table until there is 1.5 to 2.0 mm of clearance in all lateral excursions. Next, soften 2 pieces of pink base plate wax (Henry Schein Dental) in hot water; avoid overheating as melted wax is difficult to manipulate. Superimpose the pieces and then fold lengthwise to produce a strip approximately 15 mm wide. Adapt the wax strip over the teeth of the maxillary cast and exert pressure to extend the edges up to the facial/buccal and palatal borders outlined previously (Fig. 1). Use a warm, sharp knife to cut wax that extends beyond the pencil lines. It might be necessary to resoften the wax at this time. Replace the softened wax strip over the maxillary cast and close the articulator until the incisal pin contacts the guidance table; imprints of mandibular tooth surfaces should appear in the wax strip. Use a sharp blade to remove excess wax until only the indentations Fig. 6. Acrylic guard. Note pinpoint CR contacts (blue) can be seen on the occlusal surface of the acrylic guard. Fig. 7. Occlusal view of acrylic guard. Note the narrow protrusive and laterotrusive contacts made by mandibular incisors and canines, respectively. Laterotrusive contacts made by mandibular incisors have been eliminated. of the functional (buccal) mandibular cusps remain. Next, use thin (19 µm) articulating ribbon (Exacta-Film, Ardent International, Inc.)—blue side facing the wax—in a Miller forceps to record all occlusal contacts by alternately closing and opening the maxillary member of the articulator. There should be even diameter blue CR marks on the surface of the wax strip for each functional cusp. Use a warm knife to flatten and smooth the wax until there are solid CR contacts bilaterally for every mandibular buccal cusp; retain solid CR marks for as many incisors as possible (Fig. 2). At this point, all contacts should be located in shallow wax depressions. After all occlusal contacts have been recorded, use a new piece of articulating ribbon to identify potential working and balancing side interferences. Release the centric lock on the articulator. Place the ribbon on the left side (red side facing wax) and close the articulator. Move the incisal pin to the right and left sides to register any laterotrusive (working) and mediotrusive (balancing) interferences, respectively. Repeat the procedure on the opposite side of the arch to detect and eliminate all posterior working and balancing interferences; do not eliminate the blue CR dots (Fig. 3). CR markings are essential contacts and are used to equilibrate the occlusal guard. Preserve only laterotrusive canine contacts as they will be needed to develop canine guidance. Also, eliminate all eccentric contacts made by the mandibular incisors until the most prominent marks are those of the canines (Fig. 4). Preserve only the blue CR marks in the incisor region. This step establishes incisal guidance in the occlusal guard. Protrusive movement should be guided predominantly by the mandibular canines. (Mandibular incisors may assist in protrusive movement; however, no single incisor should bear the load in anterior guidance.) Use a new piece of articulating ribbon to detect (in red) and eliminate all posterior interfering contacts that appear during protrusive movement; continue to preserve all posterior blue CR contacts. Shape and smooth the wax as you develop an anterior ramp and canine eminences (Fig. 5). They should be angled approximately 30 to 45 degrees to the occlusal plane and allow continuous and smooth contact during protrusive and laterotrusive excursions. A greater angulation could restrict anterior guidance and aggravate existing masticatory muscle pain. Smooth all wax surfaces. The occlusal table should be at least half a cusp wider facially and lingually than the maxillary teeth being covered; it should extend anteriorly to provide incisal contact in full protrusive jaw position. Smooth all ridges and irregularities produced by centric closure and excursive movements so that wax extends almost to the deepest portions of the indented tracks made by the mandibular teeth. At this point, a commercial dental laboratory can invest and process the wax pattern with clear, heat-polymerizing acrylic resin in a manner similar to the way complete dentures are invested and processed. www.agd.org Intraoral delivery and equilibration of the processed occlusal guard The success of the therapy will depend on how accurately the occlusal guard is equilibrated and on the level of patient cooperation. There are a few steps to help ensure a favorable outcome. First, at the try-in appointment, deep interproximal embrasures and tooth surface irregularities are likely to interfere with complete seating of the guard. Soft disclosing wax can be melted into the intaglio surfaces of the guard to facilitate identification of binding areas. White Fit Checker (GC America, Inc.), a silicone disclosing material, may also be used to detect binding sites within the guard. A satisfactory fit is achieved when the intaglio surfaces are covered by a uniformly thin film (30 to 120 µm) of silicone material. Remove binding areas with a No. 8 carbide bur at slow speed. The appliance should fit comfortably and be adequately retentive without rocking; lip and tongue movements should not unseat the guard. Another way to ensure a favorable outcome is to place the patient in a reclined position to simulate the sleeping posture, then use articulating ribbon intraorally over occluding surfaces of all opposing teeth to equilibrate the guard. Be aware that gravitational effects will likely cause a slight posterior repositioning of the mandible. Register all mandibular CR functional cusp tip and incisal edge contacts with the blue side of the ribbon facing acrylic. If contacts are detected predominantly on one side of the arch, then flatten areas of heavy or premature contacts until there are solid CR contacts bilaterally throughout the posterior areas of the occlusal guard (Fig. 6). Eliminate all premature contacts on the appliance outside the mouth. A pear-shaped laboratory acrylic finishing bur (Komet H77E-029, Komet USA LLC) is recommended to eliminate CR prematurities and deflective contacts in all mandibular excursions until each CR functional cusp has a relatively even diameter mark. Identify anterior protrusive sliding contacts with the red side of the articulating ribbon. Then identify and eliminate posterior interfering contacts that occur during protrusion; preserve all blue CR dots. Establish broad, continuous curved contacts on the guard, guided General Dentistry May/June 2013 51 Appliance Therapy The occlusal guard: a simplified technique for fabrication and equilibration All patients should be examined routinely, 1 or 2 days after guard placement, to ensure proper use of the guard and to ascertain possible problems. If symptoms are relieved by use of the guard, then diagnosis and treatment may be assumed to be correct, and direct selective occlusal adjustment and restorative dentistry, or both, will probably succeed. If symptoms fail to abate, then the occlusion should be reevaluated. If symptoms persist, then the initial diagnosis must be questioned. Inform the patient that wearing the guard will likely cause an increase in salivation, which can last for as long as 2 weeks. Speech will likely be affected initially but will return to normal in 2 to 3 days. Fig. 8. Side view of acrylic guard in mouth. Note posterior teeth are clearly disoccluded from the guard during canine guided movement. by the mandibular canines and as many incisors as possible during protrusive movement. In canine guidance, movements must be smooth as posterior teeth are disoccluded. Eliminate all posterior laterotrusive and mediotrusive contacts on both sides of the appliance without eliminating blue CR contacts (Fig. 7). Remove all eccentric contacts made by incisors so that the predominant laterotrusive marks are those of the mandibular canines. Occlusal equilibration should avoid selective spot grinding; instead, planar grinding is preferred to eliminate occlusal locks and indentations that can trigger an increase in muscle activity. Adjust anterior contacts until they are lighter than posterior contacts. After adjusting the guard in the reclined position, raise the patient to the upright position. Re-evaluate the occlusion to account for potential anterior reshifting of the mandibular arc of closure that can produce anterior contacts that are heavier than those in the posterior areas. Readjust all anterior contacts until they are lighter than those in posterior sextants. Do not polish areas where contacts were adjusted—polishing can result in the loss of contacts. The slight roughness produced by the multi-fluted carbide bur will not harm opposing teeth, nor will it be uncomfortable for the patient. 52 May/June 2013 General Dentistry The following design features should be incorporated in an occlusal guard: (1) all functional cusp tips should contact evenly and simultaneously in CR, (2) only the mandibular canines should contact during canine-guided movements, (3) mandibular canines and as many incisors as possible should contact during protrusive movement, (4) and the occlusal guard should not move during CR closure or any eccentric movement (Fig. 8). Postinsertion instructions Instruct the patient to use finger pressure to seat and remove the occlusal guard. Once inserted over the teeth, inform the patient that biting force should be used to achieve final seating. The guard should be worn during various time intervals, depending on the patient’s diagnosis. Patients with myofacial pain should wear the guard 24 hours a day, except to eat and brush, until symptoms are relieved. Muscle discomfort is usually relieved over the course of a few days. Asymptomatic bruxers may wear the guard during sleeping hours only. Patients who report myofacial pain upon awakening should be advised to wear the guard at night. If wearing the guard leads to pain at any time, the patient should discontinue use immediately and schedule a follow-up visit to reevaluate the guard. www.agd.org Maintenance of the occlusal guard Instruct the patient to brush the guard thoroughly after it is removed from the mouth; a soft toothbrush is recommended to remove food debris. After a guard is washed and is not going to be placed immediately back in the mouth, the patient should immerse the guard in water to avoid warping. To reduce biomass levels, the guard should be soaked in sodium hypochlorite, or denture cleansers containing sodium hypochlorite, for no longer than 10 minutes.10 During maintenance care visits—every 4 to 6 months is recommended—examine the guard for previously undetected or newly developed wear facets; re-equilibrate if necessary or remake if occlusal wear results in perforation. Oral hygiene instructions must be reinforced during maintenance care visits. Discussion The greatest harm to the teeth and supporting structures occurs during parafunction, not during normal function.1 In a study of 60 subjects who reported symptoms of myofacial pain associated with clenching and bruxing, Clark et al found that 82.2% exhibited attrition of enamel on 3 or more teeth; 41.7% of the subjects exhibited wear of both enamel and dentin.11 As many as 90% of nocturnal bruxers have reported clenching.1,11 Bruxing or clenching is the first indication for treatment with an occlusal guard. Bruxers and clenchers may report the following symptoms: (1) tightness of the masticatory muscles upon awakening (diurnal bruxing and clenching can also produce this sensation) and (2) myofacial pain. During normal chewing, the loads applied to teeth are small, ranging from 2.25 lbs. to 4.5 lbs. Typically humans can only place approximately 25 lbs. of pressure on a central incisor, gradually increasing as one moves posteriorly to approximately 125 lbs. at the premolars and 200 lbs. at the molars.12 Bruxing and clenching have been found to have increasing effects on bite force.11 To add to these increased loads, total tooth contact time for bruxers was found to range from 30 minutes to 3 hours in a 24-hour period; total tooth contact time for nonbruxers was approximately 17.5 minutes.13,14 Myofacial pain is related to prolonged jaw closing muscle hyperactivity. Patients who exhibit greater levels of nocturnal electromyographic (EMG) activity are more likely to have signs and symptoms of jaw dysfunction (i.e., restricted range of mandibular movement, muscle pain on palpation, temporomandibular joint pain on palpation, and pain during mandibular border movements).12 Manns et al examined EMG activity when the masseter muscles clenched in various situations.15 Their study first measured muscle activity when patients clenched only on natural teeth and then compared muscle activity when the same patients clenched on an occlusal guard. The authors observed an increase in muscle activity when patients clenched on a guard. When the design of the guard was altered to permit only the 6 anterior teeth to contact, muscle activity decreased by 40%. When the premolars and the incisors were permitted to contact, they observed a 20% decrease in maximum bite force. Maximum muscle activity was recorded when only the molars were in contact. A properly designed occlusal guard manages these forces by loading the temporomandibular joints with all teeth touching simultaneously.15 The authors concluded that muscle activity—and joint health—is dependent on the most posterior tooth contacts and anterior guidance functions to prevent posterior tooth contact. Therefore, reduction of posterior tooth contact will reduce muscle activity.15 In an earlier study, Manns et al undertook to determine how excursive contacts affect muscle activity.16 Electromyographic activity in patients displaying canine guidance was compared to those with group function. The authors discovered that in laterotrusive and mediotrusive movements, the masseter and temporalis muscles work half as much in canine guidance as in group function. This was attributed to decreased contacts among posterior teeth during canine guidance—it is not the contact of the canines that decreases EMG activity of the elevator muscles, but the elimination of posterior contacts.16 The case was presented for designing canine guidance in occlusal guards for patients with myofacial pain. When this objective is achieved, then the temporalis and masseter muscles release their contractions and are unable to exert a magnitude of harmful force when posterior interferences are present.4 A second indication for the need to provide an occlusal guard is the increasing use of porcelain in dental restorations. Porcelain is more abrasive to opposing natural enamel than metal; its destructive capacity is well-known.17 When porcelain surfaces are adjusted to the extent that the glaze is removed and the underlying opaque porcelain is exposed, the opaque porcelain poses a greater danger than the body porcelain for the destruction of opposing enamel and restorations during function.17 Also, while porcelain is strongest under compression, it is weakest under the tensile and shear forces that occur during excursive mandibular movements. Invisible microcracks exist on the surface of porcelain.17 Tensile stresses on porcelain serve as a wedge to concentrate the stress, enlarge the cracks, and eventually promote crack propagation through the body of the porcelain. Parafunctional activity is also responsible for loosening prostheses.18 It is recommended to provide an occlusal guard for all patients with porcelain reconstructions to preserve the natural dentition and to protect porcelain restorations when they oppose one other. A third indication for an occlusal guard is prior to full mouth rehabilitation, when the OVD will be re-established and the teeth will be restored with full or partial coverage crowns. An occlusal guard is a non-invasive way to assess a patient’s tolerance to the restored OVD while preventing further loss of tooth structure. A maxillary appliance is provided after all restorative treatment is completed. After www.agd.org all definitive restorations are placed, a new appliance is constructed to protect the restorations and natural tooth structure, and to decrease myofacial pain when there is evidence of parafunctional activity. The fourth indication for an occlusal guard is the presence of tooth abfraction lesions.19 Abfractions are noncarious, V-shaped hard tissue lesions located at the cemento-enamel junction. Evidence suggests that abfractions are produced when occlusal loads applied outside the long axis during lateral excursions causes teeth to flex.20 Abfraction lesions are seen in bruxers and clenchers as they commonly apply large eccentric occlusal loads to their teeth. The efficacy of direct occlusal equilibration in these cases is still controversial, and the elimination of occlusal interferences will not necessarily eliminate bruxing or clenching habits. Providing an occlusal guard for patients with abfractions is considered a reasonable protective measure.19 A fifth possible indication for use of occlusal guards is in patients with dental implants. Lobbezoo et al acknowledged a lack of evidence implicating parafunctional activity as contributing to overloading implants or their superstructures; however, they credited occlusal guards with being able to redirect occlusal loads to the long axes of implant-supported crowns.21 Maxillary occlusal guards can also be used to eliminate occlusal loading of maxillary or mandibular implant-supported restorations. As implants do not extrude in the absence of opposing contacts, occlusal loads on maxillary implant-supported restorations may be eliminated by hollow grinding the intaglio surfaces of maxillary guards covering the implants. When mandibular implants are present, the occlusal surfaces of maxillary guards opposing implants can be relieved to eliminate occlusal loads.18 Soft occlusal guards are not recommended because they tend to produce an increase in masseter muscle activity during maximum clenching activity; hard occlusal guards decrease EMG activity in both masseter and temporalis muscles. When al-Quran & Lyons tested hard appliances, the decrease in activity was more pronounced in the temporalis muscles.2 Okeson reported that soft occlusal guards do not significantly decrease nocturnal bruxism.3 In his study, 80% of the participants experienced a General Dentistry May/June 2013 53 Published with permission by the Academy of General Dentistry. © Copyright 2013 by the Academy of General Dentistry. All rights reserved.For printed and electronic reprints of this article for distribution,please contact [email protected]. ≥25% decrease in nocturnal muscle activity with a hard occlusal guard, whereas 70% of the participants who wore a soft guard experienced a ≥25% increase in nocturnal muscle activity. Soft appliances were shown to increase nocturnal muscle activity in patients who were initially asymptomatic; therefore they are contraindicated for use in symptomatic patients.2,3,5,22 of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Florida, where Dr. Silva is a resident in the Implant Fellowship Program. Dr. Hottel is a dean and professor, Department of Prosthodontics, College of Dentistry, University of Tennessee, Memphis, where Dr. Brandt is a professor and director, AEGD Program at Lutheran Medical/ Dental Center. Conclusion References While Christensen estimated that at least one third of patients in general practice need an occlusal guard, Dao & Lavigne cautioned against over-reliance on reports about the efficacy of occlusal guards as a therapy for reduction of myofacial pain and bruxism.23,24 Their data suggests that occlusion might not be the cause of bruxism, and the decrease in myofacial pain might not be the result of treatment with an occlusal guard but, rather due to a placebo effect. However, the authors recommended using a hard occlusal appliance as a diagnostic tool to rule out pathology prior to fabricating definitive restorations.24 Kreiner et al acknowledged that the efficacy of behavioral modification and occlusal appliance therapy might be equal; however, they conceded that when there is a need to protect the natural dentition from attrition, or symptoms of myofacial pain and parafunctional activity exist, prescribing an occlusal guard is a rational treatment.25 Author information Dr. Antonelli is a professor and director, Fixed Prosthodontics Courses, Prosthodontics, College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, Florida, and an adjunct professor, Department of Prosthodontics, College of Dentistry, University of Tennessee, Memphis. Dr. Siegel is a professor and chair, Prosthodontics, College 54 May/June 2013 General Dentistry 1. Yip KH, Chow TW, Chu FC. Rehabilitating a patient with bruxism-associated tooth tissue loss: a literature review and case report. Gen Dent. 2003;51(1):70-74. 2. al-Quran FA, Lyons MF. The immediate effect of hard and soft splints on the EMG activity of the masseter and temporalis muscles. J Oral Rehabil. 1999;26(7): 559563. 3. Okeson JP. The effect of hard and soft occlusal splints on nocturnal bruxism. J Am Dent Assoc. 1987;114(6): 788-791. 4. Williamson EH, Lundquist DO. Anterior guidance: its effect on electromyographic activity of the temporal and masseter muscles. J Prosthet Dent. 1983;49(6): 816-823. 5. Attanasio R. Bruxism and intraoral orthotics. Texas Dent J. 2000;117(7):82-87. 6. Solberg WK, Clark GT, Rugh JD. Nocturnal electromyographic evaluation of bruxism patients undergoing short term splint therapy. J Oral Rehabil. 1975;2(3): 215-223. 7. Hachmann A, Martins EA, Araujo FB, Nunes R. Efficacy of the nocturnal bite plate in the control of bruxism for 3 to 5 year old children. J Clin Pediatr Dent. 1999; 24(1):9-15. 8. Dawson PE. Occlusal Splints. In: Functional Occlusion From TMJ to Smile Design. St. Louis, MO: Elsevier Mosby; 2007:380-382. 9. Okeson JP. Management of Temporomandibular Disorders and Occlusion. 7th ed. St. Louis, MO: Elsevier Mosby; 2013:470. 10. Felton D, Cooper L, Duqum I, et al. Evidence-based guidelines for the care and maintenance of complete dentures: a publication of the American College of Prosthodontists. J Prosthodont. 2011;20(Suppl 1): S1-S12. 11. Clark GT, Beemsterboer PL, Rugh JD. Nocturnal masseter muscle activity and the symptoms of masticatory dysfunction. J Oral Rehabil. 1981;8(3):279-286. 12. Spear F. Occlusion Confusion: Symposium. Seattle Study Club J. 2007;11(4):23-35. www.agd.org 13. Hagberg C. Assessment of bite force: a review. J Craniomandib Disord. 1987;1(3):162-169. 14. Graf H. Bruxism. Dent Clin North Am. 1969;13(3):659665. 15. Manns A, Miralles R, Valdivia J, Bull R. Influence of variation in anteroposterior occlusal contacts on electromyographic activity. J Prosthet Dent. 1989;61(5): 617-623. 16. Manns A, Chan C, Miralles R. Influence of group function and canine guidance on electromyographic activity of elevator muscles. J Prosthet Dent. 1987;57(4): 494-501. 17. Anusavice KJ, Phillips RW. Phillips’ Science of Dental Materials. 11th ed. St. Louis, MO: Saunders Elsevier; 2003. 18. Misch CE. The effect of bruxism on treatment planning for dental implants. Dent Today. 2002;21(9):76-81. 19. Pecie R, Krejci I, Garcia-Godoy F, Bortolotto T. Noncarious cervical lesions—a clinical concept based on the literature review. Part 1: prevention. Am J Dent. 2011; 24(1):49-56. 20. Rees JS. The role of cuspal flexure in the development of abfraction lesions: a finite element study. Eur J Oral Sci. 1998;106(6):1028-1032. 21. Lobbezoo F, Brouwers JE, Cune MS, Naeije M. Dental implants in patients with bruxing habits. J Oral Rehabil. 2006;33(2):152-159. 22. Maeda Y, Emura I, Onoue Y, et al. Mouth guard and occlusal force distribution. J Osaka Univ Dent Sch. 1990;30:125-130. 23. Christensen GJ. Abnormal occlusal conditions: a forgotten part of dentistry. J Am Dent Assoc. 1995; 126(12):1667-1668. 24. Dao TT, Lavigne GJ. Oral splints: the crutches for temporomandibular disorders and bruxism? Crit Rev Oral Biol Med. 1998;9(3):345-361. 25. Kreiner M, Betancor E, Clark GT. Occlusal stabilization appliances. J Am Dent Assoc. 2001;132(6):770-777. Manufacturers Aluwax Dental Products Co., Allendale, MI 616.895.4385, www.aluwaxdental.com Ardent International, Inc., Ossining, NY 914.923.1216, www.ardentinternationalinc.com GC America, Inc., Alsip, IL 708.597.0900, www.gcamerica.com Henry Schein Dental, Melville, NY 800.372.4346, www.henryschein.com Komet USA LLC, Rock Hill, SC 888.566.3887, www.kometusa.com Miltex, Inc., York, PA 800.654.2873, www.miltex.com Whip Mix Corporation, Louisville, KY 800.626.5651, whipmix.com