Changes in temporomandibular joint disc position and form following Herbst and fixed orthodontic treatment.
OBJECTIVE
To determine the changes in the position and form of the temporomandibular joint articular disc in adolescents with Class II division 1 malocclusion and mandibular retrognathism treated with the Herbst appliance (phase I) and fixed orthodontic appliance (phase II).


METHODS
Thirty-two consecutive adolescents went through phase I of treatment and 23 completed phase II. The temporomandibular joints were evaluated qualitatively by means of magnetic resonance images at the beginning of treatment (T1), during phase I (T2), at the end of phase I (T3), and at the end of phase II (T4).


RESULTS
Significant changes in disc position were not observed with the mouth closed between T1 x T3 (P = .317), T3 x T4 (P = .287), or T1 x T4 (P = .261). At T2, on average, the disc was positioned regressively. With the mouth open, no difference was observed between T1 x T3 (P = .223) or T1 x T4 (P = .082). We did observe a significant difference between T3 x T4 (P < .05). Significant changes in the disc form were found with the mouth closed between T1 x T2 (P < .001) and T2 x T3 (P < .001).


CONCLUSIONS
At the end of the two-phase treatment, in general terms, the position and form of the initial articular discs were maintained; however, in some temporomandibular joints some seemingly adverse effects were observed at T4.
Aidar
Luís Antônio de Arruda
LA
Department of Orthodontics, Santa Cecília University, Santos, São Paulo, Brazil. luisaidar@uol.com.br
Dominguez
Gladys Cristina
GC
Yamashita
Hélio K
HK
Abrahão
Márcio
M
D000293:Adolescent; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008335:Mandibular Condyle / Q000473:pathology; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D017289:Orthodontic Appliances, Functional; D016910:Orthodontic Brackets; D010155:Palatal Expansion Technique / Q000295:instrumentation; D011446:Prospective Studies; D063173:Retrognathia / Q000628:therapy*; D013701:Temporal Bone / Q000473:pathology; D013704:Temporomandibular Joint / Q000473:pathology; D019224:Temporomandibular Joint Disc / Q000473:pathology*