According to Behnam Aghabeigi a retrospective survey of 83 patients with an anterior open bite who underwent orthognathic surgery was carried out. Records were examined for the prevalence of abnormal TMJ signs and symptoms, including pain. A survey was mailed to these patients that consisted of: (1) the TMJ Scale, (2) the Symptom Checklist 90 (SCL90), (3) the Spielberger State-Trait Anxiety Inventory (STAI), and (4) a visual analog scale on which patients indicated their degree of satisfaction with the procedure. Thirty-seven (42%) patients responded to the survey, and 13 (15%) also attended a clinical and radiographic examination.
Multiple regression analysis was used for statistical analysis of the factors contributing to the presence and/or persistence of pain. In the preoperative group, the prevalence of pain was 32%, dysfunction 40%, and limitation of opening 7%. Age and gender were significantly associated with the presence of pain. The overall prevalence of abnormal TMJ signs and symptoms was not significantly different after orthognathic surgery. An abnormal psychologic profile was the most significant factor associated with the presence and/or persistence of pain. It is concluded that that the prevalence of temporomandibular disorders in anterior open bite patients increases with age, is significantly higher in females, and is not influenced by other occlusal variables. Furthermore, orthognathic surgery does not significantly influence temporomandibular disorders in patients with anterior open bite. Female patients, particularly those with an abnormal psychologic profile, are at a higher risk of persistent
Behnam Aghabeigi told us that it is generally agreed that the etiology of temporomandibular disorders (TMD) is multifactorial. Various emotional and mechanical factors have been implicated. There has been debate as to whether peripheral factors, such as occlusal disharmony, are of primary importance or whether central factors, such as psycho-logic variables, play the key role. Depending on the different concepts of etiology, different treatment regimens have been advocated. The dental profession historically has favored the peripheral factors and therefore embraced treatment modalities directed toward correction of occlusal dis-crepancies. Some authors1,2 even advocated orthognathic surgery for cases of TMD in combination with dysgnathia. However, it is unclear whether any association exists between the maxillomandibular relationship and TMD.3,4 Certain types of malocclusion have been reported as more likely to be associated with TMD5,6 and therefore such patients are more likely to benefit from treatment strategies addressing the occlusal disharmony. However, to date there is no randomized controlled prospective study demonstrating the efficacy of occlusal therapy in the manage-ment of TMD. Part of the difficulty in epidemiologic studies and clinical trials in relation to patients with TMD is the het-erogenous nature of the patients with regard to etiologic factors, such as occlusal or psychometric variables.
Pullinger and Seligman5 compared the role of occlusal variables between a large group of TMD patients and control subjects. They found that, except for anterior open bite (AOB), overbite and overjet char-acteristics did not distinguish the TMD patient group. Anterior open bite was rare among control subjects, and the authors reported the complete absence of AOB in the asymptomatic non-patients, as did several other authors.8–10 However, the low incidence of AOB in the general population could lead to sampling errors in such studies; this precipitates a need to study the prevalence of TMD in AOB patients.
Furthermore, the influence of orthognathic surgery on the temporomandibular joint (TMJ) has attracted a considerable amount of interest. Symptoms of TMJ disorders before and after orthognathic surgery have been documented in several clinical studies, but the reported incidence varies widely. There are reports of various degrees of improvement or deterioration, or no change at all in TMJ symptoms after orthognathic surgery. It has been suggested that orthognathic surgery may stimulate the progress of joint disease by microbleeding in the upper joint space, increased loading, disc displacement, and immobilization. Differences in the type of malocclusion, method and duration of post-operative fixation, type of osteotomy (eg, Le Fort I versus bimaxillary osteotomy15), and choice of mandibular setback procedure (eg, subcondylar versus sagittal split ramus procedure16) are among the factors that have been cited to account for the differences in TMJ symptoms after orthognathic surgery.
It has been suggested that the condyles of patients with anterior open bite may be very sensitive to functional loading, and their adaptive capacity is probably lower than in patients with deep bites. However, an analysis of the data published in relation to mixed patient groups reveals that in relation to correction of AOB, the published literature is contradictory. There are reports of significant improvement in TMD17 as well as reports of development of a significant number of new TMD cases after orthognathic surgery. Therefore, this study was carried out to assess the influence of orthognathic surgery on the TMJ in a relatively large number of patients with AOB.
Materials and methods
The clinical records of patients with an AOB who underwent orthognathic surgery during a 6-year period were examined; all patients had at least a 1-year post-operative follow-up period. The majority of cases were treated with a Le Fort I maxillary impaction, either alone (46%) or in combination with a mandibular procedure such as bilateral intraoral oblique (37%) or bilateral sagittal split osteotomy (14%). Only a very small number underwent segmental procedures (2%). In bimaxillary procedures, maxillomandibular fixation was used for a period of 4 to 6 weeks. Permission was granted by the Massachusetts General Hospital Human Studies Committee to review patient records, administer a mailed questionnaire, and recall patients for a review examination.
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