title: Fränkel appliance therapy and the temporomandibular disc: a prospective magnetic resonance imaging study.
abstract: This prospective clinical study assessed the effect of the Fränkel Functional Regulator-II (FR-II) treatment on the position and shape of the articular disc of the temporomandibular joint. The sample included magnetic resonance images of 112 temporomandibular joints taken initially (T1) and after 18 +/- 1 months (T2). The subjects were 56 white Brazilian children who were beginning their pubertal growth spurt. They had Class II Division 1 malocclusions and were selected from 800 children in neighborhood schools. They were randomly dichotomized into either the treated group (treated with the FR-II for 18 months) or the control group (not treated during the observation period). Our findings showed a low prevalence (3.57%) of disc displacement in the 112 temporomandibular joints. Mandibular propulsion with the FR-II had no unfavorable effect on the temporomandibular joints of the treated group; 100% of the patients kept an upper and interposed disc position (closed and open mouth, respectively) at T1 and T2. The control group had 7.1% partial anterior medial disc displacement, both at T1 and T2. Regarding disc morphology, the control group showed biconcave-shaped discs in 82.1% of the joints, statistically similar to the treated group (89.3%) at the beginning of the observation period. At T2, the articular disc morphology of the control group was unchanged, but that of the treated group was significantly more normal (P =.016), progressing from nonbiconcave at T1 (10.7%) to biconcave at T2 (100%). Our results showed that disc displacement is not a complication of functional appliance therapy; in fact, such treatment might help some children with incipient temporomandibular disorders.
authors.affiliation: Paulista School of Medicine, Universidade Federal de São Paulo, Brazil.
authors.forename: Alexandre A
authors.initials: AA
authors.lastname: Franco
authors.forename: Helio K
authors.initials: HK
authors.lastname: Yamashita
authors.forename: Henrique M
authors.initials: HM
authors.lastname: Lederman
authors.forename: Lucia H s
authors.initials: LH
authors.lastname: Cevidanes
authors.forename: William R
authors.initials: WR
authors.lastname: Proffit
authors.forename: Julio W
authors.initials: JW
authors.lastname: Vigorito
mesh_terms: D016009:Chi-Square Distribution; D002648:Child; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy; D015588:Observer Variation; D017289:Orthodontic Appliances, Functional / Q000009:adverse effects*; D009971:Orthodontics, Corrective / Q000009:adverse effects / Q000295:instrumentation*; D011446:Prospective Studies; D019224:Temporomandibular Joint Disc / Q000033:anatomy & histology*; D013705:Temporomandibular Joint Disorders / Q000209:etiology*