Does bite-jumping damage the TMJ? A prospective longitudinal clinical and MRI study of Herbst patients.
The aim of this prospective longitudinal study of 62 consecutively treated Class II malocclusions was to determine whether bite-jumping causes temporomandibular disorders (TMD). The function of the temporomandibular joint (TMJ) was assessed anamnestically, clinically, and by means of magnetic resonance images (MRIs) taken before (T1), after (T2), and 1 year after (T3) Herbst treatment. Average treatment time with the Herbst appliance was 7.2 months. In all subjects, Herbst treatment resulted in a Class I or overcorrected Class I dental arch relationship. Thereafter, treatment was continued with a multibracket appliance. The condyle was positioned significantly forward during treatment but returned to its original position after removal of the Herbst appliance. A temporary capsulitis of the inferior stratum of the posterior attachment was induced during treatment. Over the entire observation period from before treatment to 1 year after treatment, bite-jumping with the Herbst appliance: (1) did not result in any muscular TMD; (2) reduced the prevalence of capsulitis and structural condylar bony changes; (3) did not induce disc displacement in subjects with a physiologic pretreatment disc position; (4) resulted in a stable repositioning of the disc in subjects with a pretreatment partial disc displacement with reduction; and (5) could not recapture the disc in subjects with a pretreatment total disc displacement with or without reduction. A pretreatment total disc displacement with or without reduction did not, however, seem to be a contraindication for Herbst treatment. In conclusion, bite-jumping using the Herbst appliance does not have a deleterious effect on TMJ function and does not induce TMD on a short-term basis.
Department of Orthodontics, University of Giessen, Germany. Sabine.ruf@dentist.med.uni-giessen.de
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D000293:Adolescent; D001168:Arthritis / Q000209:etiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008335:Mandibular Condyle / Q000033:anatomy & histology / Q000473:pathology; D017289:Orthodontic Appliances, Functional / Q000009:adverse effects*; D009971:Orthodontics, Corrective / Q000009:adverse effects*; D010173:Palpation; D011446:Prospective Studies; D012016:Reference Values; D018709:Statistics, Nonparametric; D013585:Synovitis / Q000209:etiology; D013704:Temporomandibular Joint / Q000033:anatomy & histology / Q000473:pathology; D019224:Temporomandibular Joint Disc / Q000033:anatomy & histology / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000209:etiology*