Summary of evidence-based systematic reviews of temporomandibular disorders

Temporomandibular Disorders: Implications in Restorative Dentistry and Orthodontics

Over the past several decades, the science of restorative/reconstructive dentistry and orthodontics has evolved tremendously, following sound principles passed down from robust literature and scientific rationale. These principles have been solid and instrumental in enhancing dentistry, from a single tooth restoration to complex full-mouth rehabilitations. However, it must be noted that some of the principles and philosophies followed over these decades have been questioned based on the advances in science, technology, and evidence-based medicine. The scenario became complex when clinicians were faced with the question of guidance for optimum joint and muscle health as related to restorative dentistry and orthodontics.

Prevalence of temporomandibular disorders and its association with malocclusion in children: A transversal study

This study investigated the prevalence of temporomandibular disorders (TMDs) in a sample of children and adolescents and evaluated the correlation with occlusal variables. TMD signs and symptoms were recorded in 411 subjects (age range 7-15 years), divided into two groups: 214 subjects treated in Chieti (Italy) CG group and 197 in Murcia (Spain) MG group. Once the Angle dental class was identified, it was recorded if there were signs and symptoms of temporomandibular disorders (TMDs) and occlusal interferences. The percentages of signs and symptoms were compared to determine the differences among the groups for TMDs, bruxism, joint sounds, deviation during the opening, reduced opening/lateral/protrusive movements, malocclusions, and myofascial pain. There is no statistically significant difference between the two groups (χ² = 1.057, p > 0.05). Subjects with Angle Class I (37.37%), deep bite (43.43%), and increased overjet (41.41%) showed a higher prevalence of TMD symptoms.

Temporomandibular clinical exploration in Italian adolescents

OBJECTIVE

This study investigated the prevalence of the signs and symptoms of temporomandibular disorders (TMD) among Italian adolescents.

METHODS

The data were recorded from 567 subjects (246 males and 321 females; age range 11-19 years), grouped according to age and molar class relationship.

RESULTS

Forty-four point one percent of subjects showed at least one sign or symptom of TMD, which were significantly more frequent in the 16-19 year-old group (52.9%) in respect to the 11-15 year-old group (39.8%) (χ ² = 8.78; p = 0.003). Signs and/or symptoms were about 1.6 times more frequent in subjects with Class II/1 malocclusion (χ ² = 13.3, p = 0.0003), mostly for TMJ sounds (χ ² = 1.444; p = 0.036). Myalgia was more frequent in females than in males (χ ² = 3.882; p = 0.049).

CONCLUSION

TMD signs and/or symptoms among Italian adolescents seem diffused (44.1%). Therefore, all adolescents should be screened thorough medical history and clinical examination.

Analysis of the characteristics of mouthguards that affect isokinetic muscular ability and anaerobic power

PURPOSE

The purpose of this study was to estimate the effects of occlusal stability to identify action mechanisms of mouthguards, known to have a modulatory effect on limb muscle function.

MATERIALS AND METHODS

This study included 20 male subjects to perform the isokinetic muscle tests and the Wingate anaerobic power test on both knee joints under five closed-mouth conditions: without or with 4 types of mouthguards with thickness of 2 mm based on premolar area: (1) full-coverage, (2) anterior partial-coverage, (3) right posterior partial-coverage, and (4) left posterior partial-coverage. The obtained results were subjected to One-way ANOVA with repeated measures, followed by post hoc test of the contrast method (α=.05).

RESULTS

There was no significant difference between the closed position with and without a full-coverage mouthguard in all variables. However, significant differences were observed between with and without a partial-coverage mouthguard in muscular endurance during extension of the left knee, muscular power and endurance during flexion of the right knee. Additionally, significant differences were found between occlusal states with full- and partial-coverage mouthguards in muscular power and endurance during extension of the left knee.

CONCLUSION

These findings indicate the elevation of vertical dimension by 2 mm or the inducement of occlusal stability had little effect on isokinetic muscle strength and anaerobic performance, while uneven distribution of occlusal force might have some positive effects.

[Does dental class II division 2 predispose to temporomandibular disorders?]

Because of its anatomical/physiological characteristics, the Class II division 2 (class II, div. 2) is one of the malocclusions considered as a possible risk factor for Temporomandibular disorders (TMD). A literature review was conducted from the electronic databases of Medline and Elsevier Masson, through the year 2010, in order to clarify the relationships that may exist between Class II division 2 and TMD. This research helped identify 50 articles: 7 articles specifically concerned the Class II div. 2, 37 articles concerned some of the characteristics of the Class II div. 2, considered individually (Class II, deep bite, retroclined maxillary incisors, mandibular retrognathism) and 6 articles orthodontic treatment. From the conclusions of these studies, the Class II, div. 2 does not appear to represent a significant risk factor for TMD. The clearest association would involve mandibular retrognathism and the risk of articular disk displacement. However, given the low number of articles published on this topic, the methodological variability and the contradictory results, it is difficult to identify reliable conclusions and, consequently, the therapeutic indications for the treatment of Class II div. 2 patients with TMD.

Attitudes of a group of Brazilian orthodontists towards the diagnosis and management of primary headache (migraine): an electronic-based survey

Objectives

The aim of this study was to investigate the knowledge and attitudes of orthodontists in the diagnosis and management of migraine without aura.

Material and Methods

Participants were dentists, recruited among members of the Brazilian Association of Orthodontics and Facial Orthopedics (ABOR). An e-mail was sent to all ABOR members, with a link to a website, especially prepared for this research. Dentists were presented to a report of a fictional patient fulfilling diagnostic criteria for a primary headache disorder, known as migraine without aura. Participants were asked to describe how they would relieve the patient's pain. Professional procedures were classified as "adequate" or "inadequate" according to the answers given.

Results

161 valid answers were received (18.8% response rate). Of them, 36% of the actions were considered to be "adequate" procedures, while 64% were "inadequate". The results yielded 12 main procedures, based on common characteristics. Eighty-two orthodontists suggested orthodontic treatment with or without orthognathic surgery, and some suggested using stabilization appliances prior to the orthodontic treatment.

Conclusions

The majority of participants proposed inadequate therapies, and 51% suggested orthodontic correction of occlusion, including orthognathic surgery. Educational activities on migraine should also target orthodontists.

Prevalence of temporomandibular dysfunction in orthodontic treatment

The aim of our study was to investigate the prevalence of temporomandibular dysfunction (TMD) during orthodontic treatment.

MATERIAL AND METHOD

the study investigated all the patients receiving orthodontic treatment in the dentofacial orthopedic department in Casablanca in the course of the different stages of treatment over a 4-month period. We looked for a possible association between the presence of at least one sign of TMD, the Helkimo anamnesis index, the clinical Helkimo index and the following factors: age, gender, extractions, or not, of premolars, duration, type and stage of orthodontic treatment, molar and canine class, crowding, overjet, overbite and unilateral crossbite. Data were analysed using Epi-info 6.0.fr software. The analysis of the results was done using the Chi(2) test (P<0.05).

RESULTS AND CONCLUSION

no statistically significant association could be established between TMD and the various factors under investigation with the exception of the association between gender and the Helkimo anamnesis index, stage of treatment and the Helkimo anamnesis index and the Angle molar class and the Helkimo clinical index.