Perception of the relationship between TMD and orthodontic treatment among orthodontists

Students' awareness of the bruxism causes, effects and therapies

Objectives

Bruxism is a repetitive activity of the masticatory muscles characterized by clenching or grinding teeth and/or mandibular stiffening. Bruxism manifests itself in two forms: during sleeping and waking. The etiology of bruxism is multifactorial. The treatment of bruxism is mainly based on making the patient aware of the presence of the condition. The aim of the study was to assess knowledge on the causes and the effects of bruxism among Polish students as well as the possible management.

Materials and methods

The anonymous online survey was conducted among students (aged between 18 and 25 years old) of universities across Poland, using the Google Forms platform. The survey contained questions concerning bruxism causes, effects and therapies. All variants of answers in these questions contained true information about bruxism.

Results

The study found significant differences in awareness of bruxism among genders in favor of females. The awareness of bruxism among population residing in cities and in villages was comparable (p > 0.05). However, the results should be taken with care due to limited number of students that participated in the study and uneven gender distribution among urban and village residents.

Conclusions

Within the limitations of the study it can be concluded that the knowledge of bruxism among Polish students is higher in comparison with the findings from the literature, as well as the superiority of women's awareness of bruxism over men. Future studies should be conducted on greater student population, with even distribution of participants among country areas and variety of universities.

Significance

The findings may indicate the need for further education of male young adults, on bruxism causes, possible effects and therapies to increase their awareness of bruxism and encourage early diagnosis and treatment.

Examination of chewing performance with extraction and non-extraction fixed orthodontic treatment – A prospective clinical 1-year study

Objectives:

It shows that patients receiving orthodontic treatment may have a risk of developing temporomandibular disorder symptoms. The aim of this study is to examine the changes in the chewing system of occlusal contact parameters related to joint vibrations, chewing patterns, and measured excursive movements in fixed and non-extractive orthodontic treatments.

Material and Methods:

A total of 43 individuals with premolar extraction (n = 23) and without extraction (n = 20) who applied to the Department of Orthodontics, Dentistry Faculty of Istanbul Aydin University and needed orthodontic treatment were included in the study. In this study, 43 active fixed orthodontic treatment patients were conducted at the beginning (T0) and 6th month (T1) and 12th month (T2) on the parameter recorded during chewing. For occlusion analysis, T-Scan® computerized occlusion analysis recording and examination of the chewing pattern were used for JVA and JT temporomandibular joint parameters. Depending on whether the data showed normal distribution or not, differences between groups were evaluated using the Mann–Whitney or independent t-test, and intragroup differences were evaluated using the Wilcoxon sign test or paired t-test.

Results:

At the beginning, 6th month and 12th month of orthodontic treatment, it was observed that the opening, closing, and occlusion times and joint vibration frequencies in the chewing pattern in cases with and without tooth extraction, the integral value differences of total integral, and frequencies below 300 Hz and above 300 Hz were statistically significant (P < 0.001). In digital occlusion analysis values, the right-left differences were not found statistically significant in the measurements made in cases with and without extraction (P > 0.05), while there were statistically significant differences in disclusion values at the beginning, 6th and 12th months (P < 0.05).

Conclusion:

At the beginning of the orthodontic treatments with or without extraction, it was observed that the values at the joint level changed significantly in the 6th month. However, the changes in the joints during the treatment, when they return to their ideal values at the end of the 12th month, are more than the change in occlusion.

The relationship between orthodontic treatment and temporomandibular disorders: A dental specialists' perspective

Introduction:

The relationship between temporomandibular disorders (TMDs) and orthodontic treatment/malocclusion has changed from a cause-and-effect association to an idea without sufficient evidence.

Objective:

This survey was designed to assess the beliefs of different disciplines - orthodontists, oral surgeons, and oral medicine specialists - on the relationship between TMDs and orthodontic treatment, with regard to treatment, prevention and etiology of TMDs.

Method:

A survey in the form of questionnaire was designed and distributed to 180 orthodontists, 193 oral surgeons and 125 oral medicine specialists actively involved in treating TMDs. The questionnaire aimed to collect basic information about each participant and their beliefs, and clinical management of patients with TMDs.

Results:

Halve of the responding orthodontists and most of the oral surgeons (69.9%) were male participants, whereas the majority of oral medicine specialists (83.3%) were female respondents. The participants’ age ranged from 29 to 58 years. The majority of orthodontists believes that there is no relationship between orthodontic treatment and TMDs, and that orthodontic treatment does not provoke TMDs or prevent the onset of the disorder. However, oral surgeons and oral medicine specialists have different and conflicting opinions. Most surgeons tended to treat those patients, while most of the other two disciplines tended to seek an interdisciplinary approach. Chi-square test was done to find an association between the referral status and specialists’ experience, and to compare between the different disciplines’ belief.

Conclusions:

Orthodontist’s beliefs were in accordance with the scientific evidence, whereas most oral surgeons and oral medicine specialist believed that orthodontic treatment may provoke TMDs. Therefore, continuing program series development is important to embrace the concept of the multidisciplinary team approach and improve the health care and quality of life for those patients.

Temporomandibular Disorders: Fundamental Questions and Answers

This review aimed to present the current evidence-based answers to a questionnaire which was developed to evaluate the beliefs and knowledge of dental professionals concerning temporomandibular disorder (TMD). A literature review was conducted using the PubMed/Medical Literature Analysis and Retrieval System Online (MEDLINE), Cochrane, Google Scholar, and Scopus search engines from January 1980 to June 2020 corresponding to TMD diagnosis, causes, management, and consequences. A total of 50 articles were considered relevant and selected for full review. The etiology of TMD is multifactorial and complicated and involves several direct and indirect factors. Orthodontic treatment does not appear to either prevent or relieve TMD to a great degree. Nevertheless, condylar and occlusal stability reduces the risk of TMD development. As a result, an assessment of the function of masticatory system prior to beginning orthodontic therapy is fundamental. If signs and symptoms of TMD are significantly present, they should be managed before any orthodontic intervention. Moreover, psychological disorders are strongly associated with joint and facial pain. Thus, professionals who work with chronic TMD patients need to be aware of the psychological aspects of chronic pain and refer the patient for psychological evaluation when warranted. Future research elucidating a cause-effect relationship and neurobehavioral processes underlining chronic pain should be performed.

[Electrophysiological monitoring of pain afferent pathway of the trigeminal nerve and its functional plasticity in response to occlusal interference in rats]

OBJECTIVE

To observe the effect of occlusal interference on the afferent pathway of the trigeminal nerve and neuronal excitability in the trigeminal subnucleus caudalis (SPVC) of rats by electrical stimulation of the trigeminal ganglion (TG) and extracellular recordings of SPVC activities.

METHODS

Twenty male Wistar rats were randomly divided into control group and model group (n=10). In the model group, occlusal interference for 30 consecutive days was induced using light-cured flowable resin on the right maxillary molars. During occlusal interference, the pain sensitivity was scored with von Frey Fibers in the masseter. Simultaneous recordings of electrical activities from the SPVC, electrocardiogram, body temperature and electromyogram of the breath muscles of the anesthetized rats were performed, and the responses evoked by electrical stimulation of the TG were analyzed.

RESULTS

Compared with the control rats, the rats in the model group showed significantly increased pain sensitivity scores (P < 0.05) and increased spontaneous discharge frequency of the SPVC (P < 0.05). The amplitude of the SPVC responses induced by electrical stimulation of the TG showed stimulus intensity-dependent changes (P < 0.05), and the amplitude evoked by 4 mA and 8 mA stimulation was similar between the model group and the control group (P>0.05). Train stimulation (0.2 ms, 1 mA, 30 s, 100 Hz) of the TG significantly increased the discharge frequency of the SPVC only in the rats in the model group (P < 0.05).

CONCLUSIONS

The functional activities of the pain afferent pathway of the trigeminal nerve can be electrophysiologically monitored by electrical stimulation of the TG and extracellular recordings of SPVC activities in rats. Occlusal interference can increase the excitability of the neurons in the SPVC and enhance their sensitivities to TG afferent activation, suggesting the neural plasticity of the pain afferent pathway.

[Research progress on the relationship between centric relation and orthodontic treatment]

Centric relation (CR) is one of the core research contents in orthodontics, prosthodontics, and gnathology, acting as an important physiological factor in reconstructing the occlusion and adjusting the occlusal relationship. For over a century, CR is still a controversial subject in dentistry. CR has been redefined for several times, and recently, its application has been widened in orthodontics, including orthodontic diagnosis, clinical examination and analysis, and treatment goals. The purpose of this article is to review the definition of CR, its relationship with malocclusion, and the application of this relationship in orthodontic treatment.

[Investigating the effect of pre-surgical orthodontic treatment on temporomandibular joint in patients with skeletal class Ⅲ malocclusion by cone-beam computed tomography]

OBJECTIVE

To investigate the effect of pre-surgical orthodontic treatment on temporomandibular joint (TMJ) in patients with skeletal class Ⅲ malocclusion treated with orthodontic-orthognathic surgical treatment.

METHODS

Twenty-four patients with skeletal class Ⅲ malocclusion who underwent orthodontic-orthognathic surgical treatment were included in the study. Before and after the completion of orthodontic treatment, the symptoms of TMJ were examined and recorded, and the short- and the long-axis diameter of the condylar (d), condylar height (h), joint space (L) at different angles, bilateral condylar spacing (R), and the condylar angles were measured, with scanning performed by using cone-beam computed tomography (CBCT). Then, the changes of TMJ symptoms and bone structure at different periods were analyzed.

RESULTS

No significant changes were observed in the joint symptoms before and after the pre-surgical orthodontic treatment. No significant changes were found in the measurements of the bone structure of TMJ in the dimensional direction (P>0.05).

CONCLUSIONS

In the orthodontic-orthognathic surgical treatment procedure, the pre-surgical orthodontic process does not have a significant effect on TMJ.

Interdisciplinary Management of an Orthodontic Patient with Temporomandibular Disorder

A 21-year-old female patient presented with temporomandibular disorder, skeletal Class II, Angle Class II division 2 malocclusion, gummy smile, and incomplete overbite was managed successfully by splint therapy and orthodontic camouflage with miniscrew anchorage and extraction. She was treated with occlusal splint to alleviate signs and symptoms of anterior disc displacement without reduction and the associated masticatory dysfunction and revealed the true malocclusion before orthodontic treatment. Computer software facilitated the formulation of visual treatment objective (VTO) and occlusogram which guided the whole arch intrusion, retraction of the upper anterior segment, mesialization of lower left dentition, and distalization of lower right dentition. In this case report, the rationale and importance of preorthodontic splint therapy and specific considerations in orthodontic mechanics for managing this patient were discussed.