ASSESSMENT OF TEMPOROMANDIBULAR DISORDER AND OCCLUSION IN TREATED CLASS III MALOCCLUSION PATIENTS

Objective:

The aims of this study were to compare the prevalence of temporomandibular disorders (TMD) in individuals submitted to either orthodontic or ortho-surgical Class III malocclusion treatment and to assess the influence of occlusal aspects on TMD severity.

Material and methods:

The sample consisted of 50 individuals divided into two groups, according to the type of treatment (orthodontic or orthodontic with orthognathic surgery). The presence of signs and symptoms of TMD was evaluated by an anamnestic questionnaire and a clinical examination, including TMJ and muscle palpation, active mandibular range of motion, joint noises and occlusal examination.

Results:

Based on the anamnestic questionnaire, 48% had no TMD, 42% had mild TMD and 10% had moderate TMD. The presence and severity of TMD did not show any relationship with the type of orthodontic treatment (p>0.05). The chi-square test showed a positive association (p<0.05) between TMD and non-working side occlusal interferences.

Conclusion:

Based on the methodology used and the results obtained, it may be concluded that Class III orthodontic treatment was not associated with the presence of TMD signs and symptoms and the non-working side contacts can be occlusal factors of risk. There was no significant difference in TMD prevalence between the studied groups (orthodontically treated patients and patients treated with orthodontics followed by orthognathic surgery).     

ELECTROMYOGRAPHIC ACTIVITY ASSESSMENT OF INDIVIDUALS WITH AND WITHOUT TEMPOROMANDIBULAR DISORDER SYMPTOMS

Introduction:

Temporomandibular disorders (TMD) present several signs and symptoms that hinder their correct diagnosis, which is imperative on the elaboration of a treatment plan. Over the past years, several studies have been conducted to characterize and classify TMD to better understand these disorders. Therefore, the purpose of this study was to assess the electromyographic behavior of the masseter and temporal muscles in individuals with and without myogenic, arthrogenic and mixed TMD.

Method:

Forty volunteers of both genders responded to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC-TMD) Questionnaire, were submitted to clinical exam and underwent bilateral electromyographic exam of the masseter and temporal muscles.

Results:

No statistically significant difference (p>0.05) was observed during the assessment of isotonic contraction. Regarding isometric contraction, pairing between the mixed TMD group and the asymptomatic subjects did not present significant difference (p>0.05). Comparison between the myogenic and arthrogenic TMD groups and the asymptomatic group showed statistically significant difference (p<0.05). The findings of the present study demonstrated alteration on the muscle contraction pattern of TMD individuals compared to that of asymptomatic patients.     

ORTHODONTIC TREATMENT ALTERNATIVE TO A CLASS III SUBDIVISION MALOCCLUSION

Class III malocclusions are considered one of the most complex and difficult orthodontic problems to diagnose and treat. Skeletal and/or dental asymmetries in patients presenting with Class III malocclusions can worsen the prognosis. Recognizing the dentoalveolar and skeletal characteristics of subdivision malocclusions and their treatment possibilities is essential for a favorable nonsurgical correction. Therefore, this article presents a nonsurgical asymmetric extraction approach to Class III subdivision malocclusion treatment which can significantly improve the occlusal and facial discrepancies.     

EXAMINATION OF TEMPOROMANDIBULAR DISORDERS IN THE ORTHODONTIC PATIENT: A CLINICAL GUIDE

The possible association between orthodontic treatment and temporomandibular disorders (TMD) is a topic of great interest in the current literature. The true role of orthodontic therapy on the etiology of TMD, however, is still uncertain. From the clinical prospective, a thorough examination of the stomatognathic system is always necessary in order to detect possible TMD signs and symptoms prior to the beginning of the orthodontic therapy. Caution should be exercised when planning, performing and finalizing orthodontics, especially in patients who with history of signs and symptoms of TMD. The clinician must always eliminate patient’s pain and dysfunction before initiating any type of orthodontic mechanics. Muscle incoordination, unstable disc-condyle relationship and bone alterations are usual TMD conditions that can interfere with the presenting occlusal relationship. This article reviews these aspects and presents a detailed clinical guide for the examination of the orthodontic patient, considering aspects related to facial pain and dysfunction.     

A COMPUTATIONAL METHOD FOR RECORDING AND ANALYSIS OF MANDIBULAR MOVEMENTS

This study proposed the development of a new clinical tool capable of quantifying the movements of opening-closing, protrusion and laterotrusion of the mandible. These movements are important for the clinical evaluation of the temporomandibular function and muscles involved in mastication. Unlike current commercial systems, the proposed system employs a low-cost video camera and a computer program that is used for reconstructing the trajectory of a reflective marker that is fixed on the mandible. In order to illustrate the clinical application of this tool, a clinical experiment consisting on the evaluation of the mandibular movements of 12 subjects was conducted. The results of this study were compatible with those found in the literature with the advantage of using a low cost, simple, non-invasive, and flexible tool customized for the needs of the practical clinic.     

鼠创伤性颞下颌关节炎模型的建立

目的 建立创伤性颞下颌关节炎动物模型,研究间接创伤对颞下颌关节的作用。方法 使重1kg的铁块自45cm高处自由落下,由下颌角向关节凹方向撞击鼠颞下颌关节,运用组织病理和图象分析法观察创伤后1、3、7、14、21和28天各组鼠颞下颌关节的病理改变。结果 病理改变:术后1～3天,以组织的损伤和急性炎症为主;术后3～14天,以组织的进行性破坏为主;术后14～28天,以组织的增生和修复为主。结论 间接创伤引起创伤性颞下颌关节炎,创伤后组织的过度增生可能是关节紊乱和强直的主要原因。     

自体耳廓软骨瓣置换或重建颞下颌关节盘——临床疗效评价

目的　为了对己严重病变的关节盘进行置换及对关节强直进行重建关节盘 ,本文报道耳廓软骨移植的手术方法和临床疗效 ,并结合文献报道中的有关资料进行讨论。方法　对 4侧结构紊乱、4侧骨关节病、2侧滑膜软骨瘤病及 3侧关节强直 ,共 13侧颞下颌关节 ,用自体耳廓软骨瓣置换或重建关节盘 ,其中 ,6例合并应用关节刨削术 ,2侧用颞深筋膜瓣重建关节外侧囊 ,1侧耳廓软骨瓣复合颞深筋膜修复关节盘以获得足够的厚度。结果　随访期 1～ 13月 ,所有软骨瓣无感染 ,均成活 ,临床疗效满意 ,供区无或轻微变形。结论　在形态和厚度方面 ,人类的耳廓软骨瓣与关节盘较相似 ,是一种置换或重建关节盘的较好材料