2007 daher tratamiento no quirurgico en un adulto con clase iii

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2007 daher tratamiento no quirurgico en un adulto con clase iii

  1. 1. CASE REPORT Nonsurgical treatment of an adult with a Class III malocclusion Wissam Daher,a Julie Caron,b and Morris H. Wechslerc Montréal, Québec, Canada This case report describes the orthodontic treatment of a 43-year-old man with Class III malocclusion and crossbite of the maxillary anterior teeth. Treatment options included orthognathic surgery, nonextraction treatment, premolar extractions, and mandibular incisor extraction. The patient opted for nonsurgical treatment that included the extraction of a mandibular central incisor. (Am J Orthod Dentofacial Orthop 2007; 132:243-51) T he frequency of Class III malocclusions varies in different racial groups. The incidence among white people is 1% to 4%; among black people, it is 5% to 8%; in Asians, it ranges from 4% to 14%.1-3 The etiology of this condition varies from 1 person to the next; implicated factors include (1) heredity— eg, the Hapsburg chin; (2) environmental influences— eg, anterior functional shifts of the mandible or mouth breathing, which can become a positive stimulus for mandibular growth; and (3) pathologies— eg, pituitary tumors responsible for acromegaly. Patients with a Class III malocclusion can have various combinations of skeletal and dental discrepancies. It is important to diagnose these to adequately treat the underlying cause or causes of the problem. Critical factors to be evaluated include the sagittal positions of the maxilla, the mandible, the maxillary and mandibular alveolar processes, and vertical development. Guyer et al,4 for example, found that 57% of patients with a normal or prognathic mandible also had a deficient maxilla. Several clinical findings are regularly seen in Class III patients: anterior or posterior crossbites, minimal or negative overjet, retroclined mandibular incisors, proclined maxillary incisors, and functional slides from centric relation to centric occlusion. DIAGNOSIS AND ETIOLOGY A 43-year-old black man presented for an orthodontic consultation (Figs 1-5). His chief complaint was the unesthetic appearance of his maxillary anterior teeth, which were behind the mandibular incisors. There were no significant findings in his medical and dental histories. Clinical examination also confirmed the apparent facial asymmetry caused by mandibular deviation to the left as well as mandibular protrusion, a concave profile, and deviation of the nose to the right. When he smiled, only half of the maxillary incisor showed, and there was no gingival display. The patient had complete dentition including third molars. He had a Class III dental relationship on the right side and a Class I relationship on the left side. The maxillary teeth from the left central incisor to the second premolar were in crossbite, and, although the maxillary dental midline was coincident with the facial midline, the mandibular dental midline was deviated 5 mm to the left. Both overjet and overbite were negative, and there was minor bimaxillary anterior crowding. The periapical radiographs showed generalized horizontal bone loss, and the mandibular incisors appeared to have some shortening of root length. The panoramic radiograph demonstrated condylar asymmetry (longer condylar neck on the right side) and pneumatization of the maxillary sinus. There was no evidence of bone or dental pathology and no defective restorations. The cephalometric tracing and analysis (Table) indicated a skeletal Class III relationship with relative maxillary retrusion (SNA angle, 83°), mandibular protrusion (SNB angle, 85°), concave profile (N-A-Pogϭ–3°), and negative overjet (–2 mm). a Private practice, Vancouver, British Columbia, Canada. Private practice, Montréal Québec, Canada. c Professor, Department of Orthodontics, Université de Montréal, Montréal, Québec, Canada. Reprint request to: Morris H. Wechsler, 5445 Rosedale Ave, Montreal, Quebec, Canada, H4V 2H7; e-mail, morris.wechsler@mcgill.ca. Submitted, March 2005; revised and accepted, February 2006. 0889-5406/$32.00 Copyright © 2007 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2006.02.034 b TREATMENT OBJECTIVES The treatment objectives for this patient were to correct the crossbite, establish normal overbite and overjet, align the dental midlines, align and correct rotations of the anterior teeth, obtain a stable occlusal relationship, and improve the patient’s facial and dental esthetics by establishing a symmetrical smile. 243
  2. 2. 244 Daher, Caron, and Wechsler American Journal of Orthodontics and Dentofacial Orthopedics August 2007 Fig 1. Pretreatment facial photographs. Fig 2. Pretreatment intraoral photographs. TREATMENT ALTERNATIVES This adult patient had no clinically significant maxillomandibular growth potential to assist in establishing our treatment goals with orthodontics alone. Orthognathic surgery to protract the maxilla with the possibility of mandibular setback, combined with fixed orthodontic treatment, was discussed with him. Maximum esthetics, ideal occlusion, and skeletal discrepancy correction would be possible with this approach. Orthodontics alone would help camouflage some skeletal and dental aspects of the malocclusion, improving esthetics and function. The orthodontic options included (1) maxillary expansion to correct the crossbite and create arch space to derotate and align the teeth and, if necessary, mandibular incisor extraction to correct the overjet and the anterior crossbite; (2) 2 mandibular premolar extractions to upright the mandibular incisors and correct the mild crowding and the crossbite; (3) a single mandibular right premolar extraction to upright the incisors, correct the crossbite, and establish Class I canine occlusion; and (4) extraction of both mandibular second molars to establish a Class I buccal and canine occlusion and upright the mandibular incisors. The latter option would most likely require the longest treatment time to retract the premolars and the anterior segment.
  3. 3. Daher, Caron, and Wechsler 245 American Journal of Orthodontics and Dentofacial Orthopedics Volume 132, Number 2 Fig 3. Pretreatment dental models. Fig 4. Pretreatment panoramic and periapical radiographs. Fig 5. Pretreatment cephalometric tracing. TREATMENT PROGRESS The patient refused surgical procedures and opted for orthodontic treatment and camouflage, accepting maxillary dental expansion as the first stage of treatment. Treatment began with the placement of a removable expansion appliance (Fig 6) in the maxillary arch, and the patient was instructed to activate it twice a week. Subsequently, edgewise brackets were placed on all maxillary and mandibular teeth, with coil springs be-
  4. 4. 246 Daher, Caron, and Wechsler Table. American Journal of Orthodontics and Dentofacial Orthopedics August 2007 Cephalometric measurements Measurement SNA angle (°) SNB angle (°) ANB angle (°) Wits (mm) SN-Go Gn (°) MP to FH (°) U1 to NA (°) U1 to NA (mm) U1 to FH (°) L1 to NB (°) L1 to NB (mm) L1 to MP (°) U1 to L1 (°) Pog to NB (mm) Standard Initial Final 82 80 2 1 32 25 22 4 111 25 4 90 123 1 83 85 –2 –8 22 23 30 6 112 24 6 97 128 1 83 82 1 –3 26 23 25 6 111 13 1.5 85 141 0.3 improvement in the profile; the position of the upper lip is closer to the esthetic plane. Separate superimpositions of the maxilla and the mandible show that the maxillary teeth appear to have been advanced, whereas the mandibular anteriors were retroclined. Because no cephalometric radiograph was taken immediately after facemask wear, the orthodontic and orthopedic effect of the facemask could not be determined precisely. The forward position of the maxillary base at the end of treatment was most likely due to the combined effect of the facemask and the Class III elastics. Clinical examination of the mandibular position did not show that the mandible shifted backwards, and there was no evidence of a centric relation-centric occlusion shift. DISCUSSION tween the maxillary first molars and canines to advance the anterior teeth. Because there was little progress in correcting the anterior crossbite, it was decided to extract the mandibular right central incisor. The patient wore Class III elastics full time and a protraction facemask (Fig 7) at night to aid in the advancement of the maxillary arch. Treatment time was approximately 2 years. Retention consisted of a bonded lingual wire on the maxillary anterior teeth, including the canines. A spring aligner was used on the mandibular teeth. TREATMENT RESULTS At the end of treatment, the crossbites were corrected, and acceptable overjet and overbite were established (Figs 8-12). The posttreatment intraoral photographs show a good Class I occlusion on the left side, with a slight Class III canine relationship on the right. Normal overbite and overjet were achieved, and gingival heights on the maxillary anterior teeth were levelled. The occlusal views show good forms in both arches. The extraoral frontal view shows a mesofacial appearance, but the profile appears more orthognathic. Posttreatment periapical radiographs show that the level of interradicular bone remained relatively stable. The roots of the mandibular anterior teeth remained parallel despite the extraction of the mandibular central incisor. The posttreatment panoramic radiograph shows that bone levels were maintained. The maxillary teeth were advanced slightly, and the mandibular incisors were retracted. The maxillary skeletal base remained relatively stable (SNA angle, 83°), whereas the mandibular base was reduced (SNB angle, 82°), giving a positive ANB angle (1°). The maxilla advanced slightly. Comparison of the soft-tissue profile in the before and after cephalometric tracings (Fig 13) shows In treating patients with Class III malocclusions, it is essential to diagnose the components of the malocclusion correctly. In dealing with a dentoalveolar Class III, it might be possible to achieve an ideal occlusion with orthodontic tooth movement alone. However, if the etiology of the malocclusion is skeletal, or a combination of skeletal and dental factors, then treatment combining orthognathic surgery with conventional orthodontics is frequently necessary to obtain a result closer to the ideal. The timing of treatment is also important. In a case of early diagnosis of Class III malocclusion with maxillary deficiency in the late deciduous or early mixed dentition—ie, during the period of growth—a rapid palatal expansion appliance combined with a protraction facemask might be a useful treatment option.5 However, if the skeletal discrepancy is caused by excessive growth of the mandible, there seems to be little that can be done because “inhibiting mandibular growth has proven to be almost impossible,”6 and orthognathic surgery to set back the mandible at the end of adolescent growth seems to be the only viable option. For adults, fewer methods of treatment are available: either a combination of orthodontics and surgery or camouflage orthodontic treatment with various extraction combinations, depending on the severity of the malocclusion. It is important to listen to the patient’s main concerns in order to respond adequately to his or her needs. The most effective and efficient timing for such treatment has been suggested to be the early mixed dentition,7 before the patient is 8 years of age,8 before age 10,6 until the age of 12,9 or even throughout puberty.10 However, to our knowledge, no published data in the literature advocate the use of protraction force combined with maxillary expansion in nongrowing adults. For this patient, the expansion appliance and
  5. 5. Daher, Caron, and Wechsler 247 American Journal of Orthodontics and Dentofacial Orthopedics Volume 132, Number 2 Fig 6. Intraoral photographs during treatment, showing maxillary removable expansion appliance with posterior occlusal coverage. Fig 7. Facemask worn at night. the facemask therapy provided enough dentoalveolar compensation to correct the crossbite and camouflage the underlying Class III malocclusion. Although this treatment modality is somewhat unorthodox in an adult, the beneficial results were purely dental and were made possible by a cooperative and motivated patient. The effects of mandibular incisor extraction on the occlusion depend on several factors: amount of crowding in both arches, tooth mass relationship between the 2 arches (Bolton analysis), type of malocclusion, amounts of overbite and overjet, and long-term stability. The extraction of a mandibular incisor might cause increases in overjet and overbite11; this effect is usually desirable in Class III patients and detrimental in Class I and Class II patients.12,13 The tooth-mass discrepancy created by the extraction can be evaluated with a Bolton analysis, but a diagnostic wax setup is probably the better alternative for treatment-planning purposes. A concomitant maxillary anterior interproximal enamel reduction is sometimes indicated to compensate for the tooth-mass difference created by the extraction.12 Careful planning and clear treatment objectives make this treatment option viable.
  6. 6. 248 Daher, Caron, and Wechsler American Journal of Orthodontics and Dentofacial Orthopedics August 2007 Fig 8. Posttreatment facial photographs. Fig 9. Posttreatment intraoral photographs. The rationale for using a fixed retainer in the maxillary arch (and a removable retainer in the mandibular arch) was that it would counter the possibility of mandibular incisor proclination, which might lead to spacing between the maxillary anterior teeth, thus compromising esthetics in the most conspicuous area of the mouth. Riedel et al14 suggested that, in patients with crowded mandibular arches, the removal of a mandibular incisor can allow for increased stability in the mandibular anterior region even with no permanent retention. In our patient, the 3-year posttreatment records (not shown) demonstrated that the mandibular anterior segment remained stable with the removable retainer. In retrospect, an occlusal splint in the maxillary arch to prevent further incisor wear would also have been an excellent preventive measure. Owen15 described 2 patients who had only a few signs and symptoms of temporomandibular dysfunction—ie, sore muscles of mastication and limited mandibular opening. One mandibular incisor was extracted in each patient. After treatment, muscle tenderness was eliminated, and maximum opening improved. In our case, the patient had no symptoms of temporomandibular dysfunction either before or after orthodontic treatment, and we expect him to have normal temporomandibular joint function in the future. The Class III occlusion
  7. 7. Daher, Caron, and Wechsler 249 American Journal of Orthodontics and Dentofacial Orthopedics Volume 132, Number 2 Fig 10. Posttreatment dental casts. Fig 11. Posttreatment panoramic and periapical radiographs. on the right side does not appear to have negatively affected the functional occlusion of the teeth on that side. The mandibular incisor extraction helped to align the mandibular anterior segment and provided the space Fig 12. Posttreatment cephalometric tracing.
  8. 8. 250 Daher, Caron, and Wechsler American Journal of Orthodontics and Dentofacial Orthopedics August 2007 Fig 13. Comparison of profile before and after treatment. necessary to upright the incisors, thus facilitating crossbite correction. Positive overbite and overjet should help maintain the results. Light forces were used throughout the treatment to prevent or minimize apical root resorption on the mandibular incisors. The posttreatment radiographs (Fig 11) show satisfactory root alignment of the mandibular incisors with no evident root resorption. This was a compromise treatment, with an excellent final result that has admirably met the patient’s needs. The occlusion is functional and stable, and he has a pleasing smile. His quality of life has been greatly improved, and surgery was avoided. CONCLUSIONS The choice of treatment for any malocclusion must be tailored to each patient. All treatment possibilities, including those that are ideal and those that are a compromise, should be considered and explained to the patient, so that he or she can choose the most acceptable one. All problems perceived by a clinician might not be problems in the patient’s eyes. The treatment that this patient received satisfied his needs, despite its limitations. Both the patient and the orthodontist were satisfied with the results. The patient’s chief concern was addressed and treated to his satisfaction, an esthetic smile was established, and the malocclusion was treated to a satisfactory and stable result. REFERENCES 1. Ngan P. Treatment of Class III malocclusion in the primary and mixed dentitions. In: Bishara SE, editor. Texbook of orthodontics. Philadelphia: W. B. Saunders; 2001. p. 375. 2. Altemus LA. Frequency of the incidence of malocclusion in American Negro children aged 12-16. Angle Orthod 1959;29: 189-200. 3. Garner LD, Butt MH. Malocclusion in black American and Nyeri Kenyans. Angle Orthod 1985;55:139-46. 4. Guyer EC, Ellis EE 3rd, McNamara JA Jr, Behrents RG. Components of Class III malocclusion in juveniles and adolescents. Angle Orthod 1986;56:7-30. 5. Baccetti T, McGill JS, Franchi L, McNamara JA Jr, Tollaro J. Skeletal effects of early treatment of Class III malocclusion with maxillary expansion and face-mask therapy. Am J Orthod Dentofacial Orthop 1998;113:333-43. 6. Fields HW, Proffit WR. Treatment of skeletal problems in preadolescent children. In: Proffit WR, Fields HW, eds. Contemporary orthodontics. 3rd ed. St Louis: Mosby; 2000. p. 511-5. 7. McNamara JA. Mixed dentition treatment. In: Graber TM, Vanarsdall RL, editors. Orthodontics: current principles and techniques. St Louis: Mosby-Year Book; 1994. p. 508. 8. Hickham JH. Maxillary protraction therapy: diagnosis and treatment. J Clin Orthod 1991;25:102-13.
  9. 9. American Journal of Orthodontics and Dentofacial Orthopedics Volume 132, Number 2 9. Merwin D, Ngan P, Hagg U, Yiu C, Wei SHY. Timing for effective application of anteriorly directed orthopedic force to maxilla. Am J Orthod Dentofacial Orthop 1997;112:292-9. 10. Takada K, Petdachai S, Sakuda M. Changes in dentofacial morphology in skeletal Class III children treated by a modified maxillary protraction headgear and chincup: a longitudinal study. Eur J Orthod 1993;15:211-21. 11. Dacre JT. The long term effects of one lower incisor extraction. Eur J Orthod 1985;53:706-13. Daher, Caron, and Wechsler 251 12. Kokich VG, Shapiro PA. Lower incisor extraction in orthodontic treatment: four clinical reports. Angle Orthod 1984;54:139-53. 13. Zachrisson BU. Important aspects of long term stability. J Clin Orthod 1997;31:562-83. 14. Riedel RA, Little RM, Bui TD. Mandibular incisor extraction: postretention evaluation of stability and relapse. Angle Orthod 1992;62:103-16. 15. Owen AH III. Single lower incisor extractions. J Clin Orthod 1993;27:153-60.

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