No Increased Risk of Temporomandibular Disorders and Bruxism in Children and Adolescents during Orthodontic Therapy*

Effects of orthodontic aligners on 24-hour masseter muscle activity: a multiple-day electromyographic study

OBJECTIVE

This study aimed to assess the effects of aligners on masseter muscle activity by using an electromyographic device in the home environment.

METHODS

The study was performed on healthy patients who required orthodontic treatment. Three different 24 h-EMG recording sessions were performed in different conditions: without aligners, with passive aligners, and with active aligners. The non-functional MMA work index (nfMMA-WI) and the non-functional MMA time index (nfMMA-TI) for both awake and sleep hours were assessed. ANOVA test was used to compare the average activity during the three recording conditions.

RESULTS

On average, a total recording time of 204.7 ± 7.9 hours were provided for each patient. For most patients, ANOVA test showed an absence of significant differences between the recording sessions.

CONCLUSIONS

The impact of our results is not negligible: clinicians can find remarkable support to the hypothesis that the use of aligners affects the MMA only in a minority of subjects.

The Influence of Steroid Hormones on Tooth Wear in Children and in Adolescents

(1) Background: From a young age, boys are more often affected by tooth wear than girls. This suggests an influence of the male sex hormone (testosterone) on the aetiology of tooth wear. The aim of the present study was to investigate the incidence of tooth wear in relation to steroid hormone levels in children. (2) Methods: 1022 test persons aged between 10 and 18 (491 male, 531 female) from the LIFE Child study underwent medical and dental examination. Tooth wear was measured through clinical inspection. Blood samples were taken to determine hormone levels (testosterone, SHBG). The level of free testosterone was calculated from the ratio of testosterone to SHBG. Using multivariable methods, the incidence of tooth wear was analyzed as a function of hormone levels, while controlling for confounders such as age, sex, social status, and orthodontic treatment. (3) Results: The incidence of tooth wear increased with age in both sexes. Boys showed significantly more often attrition facets than girls (17.5% vs. 13.2%, p < 0.001). Subjects with tooth wear showed significantly higher free testosterone levels than those without (males: p < 0.001, females: p < 0.05). After controlling for confounding variables, the risk of tooth wear increased by approximately 30.0% with each year of life (odds ratio [OR]boys = 1.29, 95% confidence interval [CI] = 1.04−1.56; [OR]girls = 1.32, 95% CI = 1.08−1.61). In addition, the risk of tooth wear increased by 6.0% per free testosterone scale score only in boys (OR = 1.06, 95% CI = 1.01−1.12). (4) Conclusions: Tooth wear is common in children and in adolescents, and it increases steadily with age in both sexes. The stronger increase and the higher prevalence among male adolescents can be explained by the additional effect of free testosterone.

The relationship of temporomandibular disorders with Class II malocclusion as a risk factor

Objectives:

The temporomandibular joints (TMJs) play a fundamental role in mastication, deglutition, speech, and even respiration. Thus, temporomandibular disorders (TMDs) can affect the quality of life, especially if they become chronic. Considering the controversy regarding the etiology of the TMDs, this study aimed to assess the relationship of TMDs with dental malocclusion.

Materials and Methods:

Totally, 885 dentate patients between 18 years and 60 years with complete dental records and no condylar ankylosis, history of trauma, bruxism, clenching, or congenital TMJ anomalies participated in this study. Tenderness on palpation, clicking, crepitus, pain, deviation on mouth opening, open bite, deep bite, cross bite, and class of malocclusion (I, II or III) were recorded for all patients.

Results:

Of patients, 60.2% were males and 39.8% were females. Gender had no correlation with TMDs. Patients had a mean age of 34.8 years. Age had no correlation with TMDs. Of TMD symptoms, clicking had the highest frequency (23.3%) followed by deviation on mouth opening (10.6%), pain at the mouth opening (2.9%), tenderness on palpation (1.4%), trismus (1.2%), and crepitus (1.1%). Of patients, 76.7% were Class I, 13.8% were Class II, and 6.2% were Class III. Less than 2% of patients had deep bite, open bite, or cross bite.

Conclusion:

TMDs had a relatively high prevalence (35%) in our study population. Age, gender, and class of malocclusion had no correlation with TMDs; however, Class II malocclusion was slightly more prevalent among TMD patients, which needs to be taken into account by patients and orthodontists.

The evolution of temporomandibular disorders: A shift from experience to evidence

After over 80 years of much obsession as well as avoidance of the subject of temporomandibular disorders (TMDs), the dental profession is still divided over what they are and how to deal with them. Over this period, nearly every discipline in dentistry has played some role in the development of this field. Unfortunately, a significant amount of this information has been based on personal opinion, experience-based philosophies, or poorly conducted research. Furthermore, each dental specialty has been responsible for contributing to the concepts of the etiology and management of TMDs with their own professional bias; for example, orthodontists describe these problems in orthodontic terms and offer orthodontic treatments or solutions for their patients. As various treatment approaches were found to be effective at least some of the time, this has further led to misinformation and confusion within the profession. Advances in research from diverse fields, including neurophysiology, pain pathophysiology, genetics, endocrinology, behavioral sciences, and psychology, have significantly altered our understanding of TMDs and how they should be managed. The rigid mechanical and dental-based model of the past has been gradually replaced by a biopsychosocial medical model for the diagnosis and treatment of TMDs as well as other acute and chronic pain disorders. This paper discusses the evolution of our understanding of TMDs since they were first described 85 years ago. Contemporary scientific findings and their implications are presented in some detail for clinicians who wish to provide the appropriate management for their orofacial pain patients.

The association of self-reported awake bruxism with anxiety, depression, pain threshold at pressure, pain vigilance, and quality of life in patients undergoing orthodontic treatment

This study aimed to evaluate whether the presence of awake bruxism was associated with temporomandibular dysfunction symptoms, pain threshold at pressure, pain vigilance, oral health-related quality of life (OHRQoL), and anxiety and depression symptoms in patients undergoing orthodontic treatment.

Relationship between orthodontics and temporomandibular disorders

Since the end of the 20th century, the problems of the temporomandibular disorders (TMDs) have aroused interest to the orthodontists. The aim of this literature review is to present the contemporary evidence concerning the association between the presence of malocclusions and the occurrence of signs and symptoms of the TMJ. In addition, additional variables, which may affect the TMJs of a patient during the orthodontic treatment are pointed out. It is evident that there is an increased number of patients who are seeking for orthodontic treatment, not only in order to enhance their facial aesthetics and the function of mastication system, but also to relieve the symptoms of the temporomandibular joint (TMJ). There are multiple etiological factors that have been associated with the TMDs and they may be manifested by pain and/or sounds of TMJ. In addition, during the clinical examination it can be detected a deviation from the normal function of the mandible.

[Orthognathic surgery: the incisor decompensation and its effect on articulation]

INTRODUCTION

The surgical protocols are based on arches preparation before or immediately after the surgical phase. Incisor guides normalization is achieved by incisor decompensation in three dimensions. Place and extend of surgical movements depend on the incisor position obtained at the end of orthodontic preparation. Extraction versus non extraction depends on incisor position planning. Orthognathic surgery induces muscular and temporo-mandibular joint stress which can cause temporo mandibular dysfunction (TMD).

OBJECTIVES

This article studies relations between incisor decompensation amplitude, orthognathic surgical procedures and risk to create or to increase TMD.

CONCLUSIONS

Sagittal, vertical and transversal incisor decompensation impact to place and amplitude of surgical movements. Incisor decompensation does not seem to induce TMD during orthodontic preparation even if occlusal guide controls are lost. Temporo mandibular dysfunction degrees define surgical movements area, moderate specially mandibular surgical movements and incisor decompensation objectives.

Can different occlusal positions instantaneously impact spine and body posture? : A pilot study using rasterstereography for a three-dimensional evaluation

PURPOSE

Orthodontists influence dental occlusion directly. To suggest any link between dental occlusion and body posture is highly contentious, as evidenced by the literature. Rasterstereography, an optical technique that enables three-dimensional (3D) body measurements to be collected, has not yet been used to impartially examine whether different occlusal positions could instantaneously alter spine and body posture. We therefore set out to use this technique to nonsubjectively evaluate this question under static conditions.

METHODS

Optical body scans were collected for 44 subjects, using the Diers formetric 4D system, for seven different mandible positions. In total, ten spinal and body posture parameters were assessed (trunk inclination, trunk imbalance, pelvic tilt, pelvic torsion, fleche cervicale, fleche lombaire, kyphotic angle, lordotic angle, surface rotation, and lateral deviation) for each mandible position and compared with scans performed with habitual intercuspation (HIC).

RESULTS

Significant body posture deviations were found for the fleche cervicale (position of the mandible: right eccentrically), fleche lombaire (positions of the mandible: physiologic rest position, cotton rolls on both sides, bite elevation 1 mm), and the kyphotic angle (positions of the mandible: cotton rolls on both sides, right eccentrically). No other significant differences were detected.

CONCLUSIONS

Data for the parameters that varied with different dental occlusions generated high standard deviations. Therefore, within the limitations of this pilot study, we could not conclusively associate dental occlusion to an instantaneous impact on the tested parameters. The posture changes that we detected could also have arisen from individual neuromuscular compensation; a possibility that must now be ruled-in, or out, by further research studies with a higher number of subjects.

Influence of orthodontic treatment on temporomandibular disorders. A systematic review

Objectives

The aim of this literature systematic review was to evaluate the possible association between malocclusions, orthodontic treatment and development of temporomandibular disorders. Material and Methods: A search was carried out on PubMed-Medline database from January 2000 to August 2013 using the keywords “orthodontics and temporomandibular disorders”, “orthodontics and facial pain” and “malocclusion and temporomandibular disorders”. Human studies included in the study were those assessing signs and symptoms of temporomandibular disorders in relation to orthodontic treatment.

Material and Methods

A search was carried out on PubMed-Medline database from January 2000 to August 2013 using the keywords “orthodontics and temporomandibular disorders”, “orthodontics and facial pain” and “malocclusion and temporomandibular disorders”. Human studies included in the study were those assessing signs and symptoms of temporomandibular disorders in relation to orthodontic treatment.

Results

The search strategy resulted in 61 articles. After selection according to the inclusion/exclusion criteria 9 articles qualified for the final analysis. The articles which linked orthodontics and development of temporomandibular disorders showed very discrepant results. Some indicated that orthodontic treatment could improve signs and symptoms of temporomandibular disorders, but none of them obtained statistically significant differences.

Conclusions

According to the authors examined, there is no evidence for a cause-effect relationship between orthodontic treatment and temporomandibular disorders, or that such treatment might improve or prevent them. More longitudinal studies are needed to verify any possible interrelationship.

Key words:Malocclusion and temporomandibular disorders, orthodontics and facial pain, orthodontics and temporomandibular disorders, temporomandibular disorders, temporomandibular dysfunction.

Reliability of clinical symptoms in diagnosing temporomandibular joint arthritis in juvenile idiopathic arthritis

OBJECTIVE

Temporomandibular joint (TMJ) arthritis, commonly considered oligoarthritic/asymptomatic, occurs frequently in children with juvenile idiopathic arthritis (JIA), and gadolinium-enhanced magnetic resonance imaging (Gd-MRI) has proved to be a sensitive diagnostic tool in this context. We compared the reliability of clinical examinations to Gd-MRI results in diagnosing the condition.

METHODS

Patients with JIA (134 consecutive) underwent routine clinical and Gd-MRI examinations. The clinical items examined were clicking, tenderness (TMJ/adjacent muscles), and mouth-opening capacity. Blinded MRI reading focused on inflammation (synovitis/hypertrophy). After statistical power analysis, the clinical findings for 134 healthy controls were included. Contingency analysis was used to determine the sensitivity, specificity, and frequency of clinical symptoms (JIA/healthy controls); Cohen's κ was used to establish the interrater reliability.

RESULTS

Statistically significant differences were observed between JIA and healthy control groups with regard to the concise screening items (power analysis > 0.95), whereas no differences in mouth-opening capacity were noted. In 80% of the patients with JIA, Gd-MRI revealed signs of TMJ arthritis, with positive correlations between concise screening items and Gd-MRI results. The average specificity was 0.81, but the sensitivity was low, at 0.42. Combining items led to a marked increase in the sensitivity (0.73). There was a high rate of both false-negative and false-positive results (corresponding to clinical underdiagnosis or overdiagnosis of TMJ arthritis).

CONCLUSION

Despite a relatively high specificity, clinical examination alone does not seem sufficiently sensitive to adequately detect TMJ arthritis. Thus, a relatively high number of cases will be missed or overdiagnosed, potentially leading to undertreatment or overtreatment. Gd-MRI may support correct diagnosis, thereby helping to prevent undertreatment or overtreatment.

[Course of action in front of children or adolescent suffering from temporomandibular disorders]

Temporomandibular disorders are described in children from the age of 4. Their prevalence and severity increase strongly during the second decade, which corresponds to the period of orthodontic treatments. At this age the most common symptoms are joint clicking sounds (more than 70% of the cases), sometimes accompanied by episodes of intermittent locking. They would be favored by oral parafunctional activities (gum chewing, biting habits, bruxism...), ligamentous hyperlaxity and modification of the intra-articular space relations during growth. The questioning of the patient and his parents and clinical examination (muscular, articular and occlusal) are essential and very often sufficient for establishing the diagnosis. Even more than in the adult, the therapeutic attitude must rely on conservative and non-irreversible methods (explanations, suppression of the parafunctions, occlusal splints in the case of severe bruxism). These considerations are illustrated by the presentation of two representative clinical cases of temporomandibular disorders frequently encountered in children and adolescents.

Persistent orofacial muscle pain

The pathophysiology of persistent orofacial myalgia has been the centre of much controversy. In this article we suggest a novel descriptive term; 'persistent orofacial muscle pain' (POMP) and review current evidence that supports the hypothesis that the induction of POMP involves the interplay between a peripheral nociceptive source in muscle, a faulty central nervous system component and decreased coping ability. In this context it is widely accepted that a complex interaction of variable intrinsic and extrinsic factors act to induce POMP and dysfunction.

Temporomandibular disorders in German and Chinese adolescents

OBJECTIVE

The etiology of temporomandibular disorders (TMD) remains unclear. The aim of this study was, by comparing the prevalence of TMD between adolescents of different ethnic origin, to examine whether certain genetic factors may play a role in causing TMD.

SUBJECTS AND METHODS

We assessed the prevalence of TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) in 1,058 subjects (561 German, 497 Chinese) aged 13 to 18 years from two general population samples.

RESULTS

In total, the prevalence of RDC/TMD diagnoses was 13.9% (N = 147). The difference between German (13.0%, N = 73) and Chinese adolescents (14.9%, N = 74) was not statistically significant. After controlling for the effects of age, gender and orthodontic treatment using multivariable logistic regression analyses, the prevalence of RDC/TMD group II diagnoses (disc displacement) was lower in China than Germany (odds ratio [OR] = 0.5, 95% confidence interval [CI]: 0.3-0.8), whereas the prevalence of RDC/TMD pain diagnoses (group I, III) was higher in China (OR = 3.3, 95%-CI: 1.7-6.5).

CONCLUSIONS

Our study reveals obvious differences in the prevalence of TMD between adolescents of different ethnic origins (Asians and Europeans). These differences cannot be attributed to cultural differences alone, which implies the involvement of genetic factors in the etiology of TMD.

[Can orthodontic treatment generate temporomandibular disorders and pain? A review]

While considered for years to play the primary role in the etiology of temporo-mandibular joint disturbances (TMD), occlusal discrepancies are now considered to be just one causative factor among many. Recent studies, literature reviews or meta-analyses, and longitudinal studies with follow-up of children treated for many years all conclude that there is no risk of orthodontic treatment giving rise to episodes of temporo-mandibular disorders. The signs of TMD appearing during the course of orthodontic treatment should be considered in the context of the epidemiology of the disorder, which is characterized by a strong increase in its occurrence during adolescence. In conclusion, it should be stated that if orthodontic treatment can no longer be considered as one of the etiopathogenic factors in the TMD complex, there are no scientific arguments to justify the converse, that there are indications for orthodontic treatment whose sole goal would be the treatment of TMD.