Masticatory function in patients with dentofacial deformities before and after orthognathic treatment-a prospective, longitudinal, and controlled study.

OBJECTIVES: The aim of this study was to investigate the self-estimated masticatory ability and masticatory performance in patients with dentofacial deformities before and after orthognathic treatment; in comparison to an age- and gender-matched control group. SUBJECTS AND METHODS: The masticatory ability and masticatory performance were evaluated in 121 consecutive patients (treatment group), referred for orthognathic treatment. Eighteen months after treatment, 98 patients (81%) completed a follow-up examination. Masticatory ability was assessed on a visual analog scale, while the masticatory performance was evaluated by a masticatory test using round silicon tablets. Signs and symptoms of temporomandibular disorders (TMD) were registered by a clinical examination and a questionnaire. The control group comprised 56 age- and gender-matched subjects who were examined at baseline. RESULTS: At the baseline examination, the treatment group had a significantly lower masticatory ability and performance compared with the control group. After treatment, the masticatory ability significantly improved in the treatment group and reached the same level as in the control group. The masticatory performance index increased significantly but was still lower than in the control group. Both the masticatory ability and masticatory performance were affected by the number of occlusal contacts during maximal biting pressure and by the self-estimated overall symptoms of TMD. CONCLUSIONS: Patients with dentofacial deformities, corrected by orthognathic treatment, have a significant positive treatment outcome in respect of masticatory ability and masticatory performance. Furthermore, the occlusion and symptoms of TMD have an impact on both masticatory ability and masticatory performance.

Can orthodontic treatment improve mastication? A controlled, prospective and longitudinal study.

OBJECTIVES: To prospectively and longitudinally evaluate the self-perceived masticatory ability and the tested masticatory efficiency in orthodontically treated and untreated groups. DESIGN: Prospective observational cohort. SUBJECTS AND METHODS: Three groups of age matched adolescent girls were included. Sixty-five Class II subjects received orthodontic treatment fixed appliance treatment (Orthodontic group), 58 subjects were orthodontically untreated (Class II group) and 60 subjects had a normal occlusion (Normal group).The self-perceived masticatory ability was assessed on a visual analogue scale while the masticatory efficiency was evaluated with a masticatory efficiency test using round silicon tablets. Registrations were performed at the start and after two years when all subjects in the Orthodontic group had finished orthodontic treatment. RESULTS: Over the two-year period the self-perceived masticatory ability increased significantly in the Orthodontic group. After treatment, the Orthodontic group perceived their masticatory ability as high as the Normal group did. The masticatory efficiency increased significantly, during the two years, in all three groups. However,the normal occlusion group presented a significantly better masticatory efficiency than both the Orthodontic group and the Class II group on both registrations. CONCLUSIONS: Orthodontic treatment was beneficial for the self-perceived masticatory ability. The masticatory efficiency increases with age during adolescence. Normal occlusion subjects had a better masticatory efficiency than subjects with orthodontically treated as well as untreated Class II malocclusion.

TMD in consecutive patients referred for orthognathic surgery.

OBJECTIVE: To answer the question whether temporomandibular disorders (TMD) were more common in a group of individuals referred for orthognathic surgery than in a control group. The null hypothesis was that neither the frequency of signs and symptoms of TMD or diagnosed TMD would differ between the patient group and a control group. MATERIALS AND METHODS: A sample of 121 consecutive patients referred for orthognathic surgery at the Department of Oral Maxillofacial Surgery, Malmö University Hospital, Sweden, was interviewed and examined regarding signs and symptoms of TMD and headaches. A control group was formed by 56 age- and gender-matched individuals attending the Department of Oral Diagnosis, Faculty of Odontology, Malmö University, Sweden, and Public Dental Health Clinic in Oxie, County of Skane, Sweden. TMD diagnoses were used according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). RESULTS: The patient group showed more myofascial pain without limited opening, disc displacement with reduction, and arthralgia according to RDC/TMD than the control group. The patient group also had more symptoms and signs of TMD in general. CONCLUSIONS: The null hypothesis was rejected because patients who were to be treated with orthognathic surgery had more signs and symptoms of TMD and higher frequency of diagnosed TMD compared with the matched control group.

Alterations of temporomandibular disorders before and after orthognathic surgery: a systematic review.

OBJECTIVE: To answer the question whether orthognathic surgery does affect the prevalence of signs and symptoms of temporomandibular disorders (TMDs). MATERIALS AND METHODS: A literature survey in the PubMed and Cochrane Library electronic databases was performed and covered the period from January 1966 to April 2006. The inclusion criteria were controlled, prospective or retrospective studies comparing TMDs before and after orthognathic surgery in patients with malocclusion. There were no language restrictions, and three reviewers selected and extracted the data independently. The quality of the retrieved articles was evaluated by four reviewers. RESULTS: The search strategy resulted in 467 articles, of which 3 met the inclusion criteria. Because of few studies with unambiguous results and heterogeneity in study design, the scientific evidence was insufficient to evaluate the effects that orthognathic surgery had on TMD. Moreover, the studies had problems with inadequate selection description, confounding factors, and lack of method error analysis. CONCLUSION: To obtain reliable scientific evidence, additional well-controlled and well-designed studies are needed to determine how and if orthognathic surgery alters signs and symptoms of TMD.