The prevalence of bruxism and oral parafunction activities among Israeli juveniles with autism spectrum disorder: A preliminary study during the COVID-19 pandemic

OBJECTIVE

To evaluate the prevalence of oral habits, bruxism, and Temporomandibular Disorders (TMD) injuvenileswithautisticspectrumdisorder(ASD).

METHODS

Data included 165 juveniles diagnosed with ASD, allocated to younger group aged 6 21 (n=86) and older group aged 13-21 (n=79).

RESULTS

Sleep bruxism was reported by 26.7% in the younger group and by 5% in the older group. Awake bruxism was reported by 22% and 17.7%, respectively. Oral habits were reported by 43% of all participants, with similar rate in both groups. TMD related p ain was low in both groups (6.3% and 7% respectively). The influence of the COVID 19 pandemic on oral parafunction was moderate in the younger group (17.4%) and mild in the older group (8.6%), influence on bruxism was mild in both groups (5.8% and 2.5%, respectively).

CONCLUSION

The prevalence of bruxism and oral parafunctions was similar to the reported in the literature for the general population.

An exploratory study on the association between serotonin and sleep breathing disorders

This exploratory observational study aimed to evaluate whether the blood levels of serotonin and enzymes involved in serotonin synthesis are associated with sleep breathing parameters. A total of 105 patients were included in this study, who were subjected to single-night polysomnography with simultaneous audio-video recordings. Peripheral blood samples were collected to estimate the serum levels of serotonin, tryptophan hydroxylase 1 (TPH1), and aromatic l-amino acid decarboxylase (AADC). Results showed a negative correlation between blood serotonin levels, and oxygen desaturation index (ODI) (p = 0.027), central apnea (p = 0.044) and obstructive apnea (OA) (p = 0.032) scores. Blood TPH1 levels were negatively correlated with average (p = 0.003) and minimal saturation (p = 0.035) and positively correlated with apnea-hypopnea index (p = 0.010), OA (p = 0.049), and hypopnea index (p = 0.007) scores. A tendency to sleep-disordered breathing seemed to co-occur with lower blood serotonin and higher TPH1 levels.Clinical Trial Registration : www.ClinicalTrials.gov , identifier NCT04214561.

Sleep bruxism in children, from evidence to the clinic. A systematic review

Objectives

The present paper aims to systematically review the literature published from 2015 to 2023 on bruxism in children with the aim to compilate the best available evidence.

Materials and Methods

A systematic search in the National Library of Medicine's PubMed, Medline (EBSCO), SCOPUS, and Google Scholar databases was performed to identify all studies on humans assessing genetic, biopsychosocial, and sleep factors assessed with any different approach for sleep bruxism (SB) in children and its interventions. The selected articles were assessed independently by the two authors according to a structured reading of the article's format (PICO). The quality of the articles was evaluated using Quality Assessments Tool for Experimental Bruxism Studies (Qu-ATEBS) and the JBI critical appraisal tools.

Results

A total of 16 articles were included for discussion in the review and grouped into questionnaire/parental-report (n = 7), SB assessment through parental report of SB and clinical examination (n = 4), and instrumental assessment (n = 5) studies. The total quality scores evaluated with STROBE and Qu-ATEBS were high for all included papers. However, in general, there was no control of bias strategies and there was no control group in the intervention studies.

Conclusions

Investigations based on self-report, clinical, and instrumental bruxism assessment showed a positive association with genetics, quality of life aspects (school and emotional functions and overuse of screen-time), mother anxiety and family conformation, diet, alteration in sleep behaviors and architecture, and sleep breathing disorders. Additionally, the literature presents options to increase airway patency and, thus, reduce the occurrence of SB. Tooth wear was not found to be a major sign of SB in children. However, methods of SB assessment are heterogeneous and hamper a reliable comparison of the results.

Ecological Momentary Assessment of Awake Bruxism Behaviors: A Scoping Review of Findings from Smartphone-Based Studies in Healthy Young Adults

BACKGROUND

The recent introduction of ecological momentary assessment (EMA) smartphone-based strategies has allowed achieving some interesting data on the frequency of different awake bruxism (AB) behaviors reported by an individual in the natural environment.

OBJECTIVE

The present paper aims to review the literature on the reported frequency of AB based on data gathered via smartphone EMA technology.

METHODS

On September 2022, a systematic search in the Pubmed, Scopus and Google Scholar databases was performed to identify all peer-reviewed English-language studies assessing awake bruxism behaviors using a smartphone-based Ecological Momentary Assessment. The selected articles were assessed independently by two authors according to a structured reading of the articles' format (PICO).

RESULTS

A literature search, for which the search terms "Awake Bruxism" and "Ecological Momentary Assessment" were used, identified 15 articles. Of them, eight fulfilled the inclusion criteria. The results of seven studies using the same smartphone-based app reported a frequency of AB behaviors in the range between 28.3 and 40% over one week, while another investigation adopted a different smartphone-based EMA approach via WhatsApp using a web-based survey program and reported an AB frequency of 58.6%. Most included studies were based on convenience samples with limited age range, highlighting the need for more studies on other population samples.

CONCLUSIONS

Despite the methodological limits, the results of the reviewed studies provide a standpoint for comparison for future studies on the epidemiology of awake bruxism behaviors.

Impact of bruxism on craniomandibular morphology: A cone-beam computed tomographic study

OBJECTIVE

The main goal of this work was to address craniomorphological characteristics of patients with bruxism when compared to those without bruxism using cone beam computed tomography (CBCT) imaging.

METHODS

Seventy CBCT images of an equal number (n = 35) of orthodontic patients with and without bruxism (age range, 18-44 years) were retrospectively analyzed. Sagittal evaluation, mandibular shape, and skeletal asymmetry were systematically assessed in both groups.

RESULTS

Significant differences (p < 0.05) were observed between groups for Right Articular Fossa (AF) - Axial Plane (AP) and Left AF - AP (B > NB), Right Gonial Angle (GA), Left GA, Sella-Nasion and Occlusal Plane (B < NB). Age (13%), Condyle-Gonion (18%), AF to AP (67%), and Mental-AP (16%) had the greatest impact on bruxers.

CONCLUSION

In this study, the CBCT 3D image showed significant differences in craniofacial morphology, particularly in the mandibular structure of bruxers compared with non-bruxers.

Temporomandibular Disorders and Bruxism among Sex Workers-A Cross Sectional Study

Sex workers are a highly underprivileged population which is present all around the world. Sex work is associated with negative social stigma which affects all aspects of the sex workers' lives including healthcare, service providers and police. The stigma may result in increased stress, mental health problems, feelings of isolation and social exclusion. In the present study, 36 sex workers (SW) and 304 subjects from the general population in Israel (GP) were evaluated for the presence of bruxism and Temporomandibular disorders (TMD), with the use of Diagnostic Criteria for Temporomandibular Disorders (DC/TMD- Axis I). When compared to the general population, sex workers presented larger maximal assisted mouth opening and higher prevalence of the following TMD diagnoses: Disc displacement with reduction, Myalgia, Myofascial pain with referral, Arthralgia (left and right) and Headache attributed to TMD. The odds of sex workers suffering from one of these diagnoses were twice to five times higher than those of the general population. The study shows that health problems of sex workers go beyond venereal diseases, HIV and mental disorders which are commonly studied. Oral health, TMD and oral parafunctions are some of the additional health issues that should be addressed and explored in this population.

Painful Temporomandibular Disorders, Bruxism and Oral Parafunctions before and during the COVID-19 Pandemic Era: A Sex Comparison among Dental Patients

Aim: To evaluate the effect of the current coronavirus pandemic on the prevalence of bruxism, oral parafunctions and painful Temporo-Mandibular Disorders (TMDs) and to evaluate the influence of the pandemic on both sexes. Methods: This retrospective study included 288 dental patients who underwent complete anamnesis and examination according to the Diagnostic Criteria for TMD. The study evaluated two patient populations according to the date of examination: (a) pre-COVID-19 pandemic era (108 patients); (b) COVID 19 pandemic era, where 180 patients were examined during the pandemic. Results: A significant increase in parafunction activity was found in both men and women (p < 0.001) during the COVID-19 pandemic. Awake bruxism (AB) and sleep bruxism (SB) was more prevalent during the COVID-19 pandemic solely in women (AB-p < 0.001; SB-p = 0.014). Conclusions: Men and women were affected by the ongoing stress due to the COVID-19 pandemic, yet women showed a higher influence as compared to men. The long-term exposure to elevated levels of anxiety and stress may aggravate or trigger stomatognathic detrimental conditions. Dentists should be aware and regularly monitor their patients regarding the possible existence and consequences of bruxism and TMD.

Association Between Primary Headache and Bruxism: An Updated Systematic Review

AIMS

To answer the question: among observational studies, is there any association between primary headaches and bruxism in adults?

MATERIALS AND METHODS

A systematic review of observational studies was performed. The search was performed in seven main databases and three gray literature databases. Studies in which samples were composed of adult patients were included. Primary headaches were required to be diagnosed by the International Classification of Headache Disorders. Any diagnostic method for bruxism was accepted. Risk of bias was evaluated using the Joanna Briggs Institute Critical Appraisal Tool and the Meta-Analysis of Statistics Assessment and Review Instrument (MAStARI) tool. Associations were analyzed by calculating odds ratios (OR) in Review Manager 5.3 software. The evidence certainty was screened by Grading of Recommendations Assessment, Development, and Evaluation criteria.

RESULTS

Of the 544 articles reviewed, 5 met the inclusion criteria for qualitative analysis. The included studies evaluated both awake and sleep bruxism, as well as tension-type headaches and migraines as primary headaches. Among two migraine studies, one showed an OR of 1.79 (95% CI: 0.96 to 3.33) and another 1.97 (95% CI: 1.5 to 2.55). On the other hand, among three tension-type headache studies, there was a positive association only with awake bruxism, with an OR of 5.23 (95% CI: 2.57 to 10.65). All included articles had a positive answer for more than 60% of the risk of bias questions. The evidence certainty varied between low and very low. Due to high heterogeneity among the studies, it was impossible to perform a meta-analysis.

CONCLUSION

Patients with awake bruxism have from 5 to 17 times more chance of having tension-type headaches. Sleep bruxism did not have any association with tension-type headache, and the association with migraines is controversial.

Consecutive Controlled Case Series on Effectiveness of Opipramol in Severe Sleep Bruxism Management-Preliminary Study on New Therapeutic Path

BACKGROUND

Sleep bruxism (SB) management aims to reduce the number and magnitude of bruxism episodes per hour of a patient's sleep and, therefore, reduce the potentially negative clinical consequences. Opipramol belongs to the group of tricyclic antidepressants (TCAs) and is considered as an atypical TCA, as it acts primarily as a sigma receptor agonist. This study aimed to preliminarily determine the effectiveness of opipramol in the management of severe SB.

METHODS

A total of 19 otherwise healthy participants with severe SB diagnosed during stage I video polysomnography (vPSG) were subjected to an 8-week pharmacotherapy trial with a 100 mg bedtime daily dose of opipramol and were then analyzed by control stage II vPSG.

RESULTS

The participants included 14 females and 5 males, aged 20-47 years (mean ± standard deviation: 32.32 ± 8.12). A comparison of stage I and II vPSG recordings showed a decrease in all the studied SB parameters in 78.85% of participants. Only in a small group of participants (15.53%) was a non-significant increase of SB parameters observed.

CONCLUSIONS

A single 100 mg dose of opipramol at bedtime seems to positively affect the reduction of SB in otherwise healthy individuals diagnosed with severe SB. However, the subject requires further research on a larger population including a control group.

Genetic basis of sleep bruxism and sleep apnea-response to a medical puzzle

Sleep bruxism (SB) and obstructive sleep apnea (OSA) are co-occurring sleep conditions. The study aimed to evaluate the association of selected single-nucleotide polymorphisms (SNPs) occurring within the genes of the serotonin and dopamine pathways in SB and OSA and investigate the relationship between them. The study group included 100 Caucasian patients. SB and OSA were diagnosed in 74 and 28 patients, respectively. In addition, 125 unrelated Caucasian healthy blood donors served as randomly selected controls to enable comparison of polymorphisms. The following SNPs were analyzed: rs2770304 and rs6313 within the serotonin receptor encoding gene (HTR2A), rs4680 polymorphism of the catechol-O-methyltransferase (COMT) gene, and rs686 within the dopamine receptor (DRD1) encoding gene. The prevalence of the DRD1 rs686 G variant (GG homozygosity) was found to be high in the study group compared to the control group. Bruxism episode index (BEI) was found to be significantly increased in the HTR2A rs6313 TT homozygotes compared to the heterozygous patients. Moreover, within a group of the HTR2A rs2770304 TT homozygous cases, a statistically significant correlation was observed between BEI and apnea-hypopnea index. These results indicate that DRD1 rs686 may potentially affect predisposition to SB, that HTR2A rs6313 SNP may be involved in SB pathogenesis, and that HTR2A rs2770304 polymorphism might contribute to the association between SB and OSA. This suggests a possible genetic contribution to the etiology of primary SB.

Great potential of ultrasound elastography for the assessment of the masseter muscle in patients with temporomandibular disorders. A systematic review

Objective:

To summarize the available evidence on the use of elastography in the assessment of the masseter muscle in healthy individuals and patients with masseter muscle disorders.

Methods:

Systematic literature review has been performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

Results:

16 of 142 studies identified were analyzed. Elastography was used in seven studies. Heterogeneity was observed in terms of study protocols, devices, patients, units of measure, and results. Elasticity values showed a correlation between the left and right masseter muscle side in healthy people, but not in patients with temporomandibular disorders (TMDs). Elasticity values increased in TMD and were correlated with the severity of TMD symptoms. Phantom studies proved the high reliability of elastography.

Conclusion:

Elastography is a promising tool for the assessment of the masseter muscle elasticity, but the evidence is insufficient. Studies on larger groups are needed to determine the accuracy of elastography to characterize masticatory muscle disorders.

Prevalence and Overlaps of Headaches and Pain-Related Temporomandibular Disorders Among the Polish Urban Population

AIMS

To investigate the prevalence and overlaps of headaches and pain-related temporomandibular disorders (TMD) among the Polish urban population.

METHODS

The study was conducted in four Polish cities (Wroclaw, Lublin, Katowice, and Lodz) between February and November 2017. Participation in the study was voluntary. The examination consisted of two parts: a clinical examination of TMD using the Diagnostic Criteria for TMD Examination Form and the Head-HUNT Study questionnaire filled in by the participants to determine the occurrence and type of headaches. An experienced and qualified clinician trained all the examiners in the clinical examination protocol. Statistical analyses were based on descriptive and nonparametric statistics. In addition, univariate logistic regression was used. The significance level was set at α = .05.

RESULTS

Overall, 213 individuals were examined (149 women and 64 men). The mean age of the participants was 37 ± 15.82 years. The diagnosis for 55.9% of the participants was pain-related TMD, including myalgia (47.4%), myofascial pain (14.1%), arthralgia (21.1%), or headache attributed to TMD (10.3%). In the study population, 48.8% were diagnosed with temporomandibular joint disorders, most frequently disc displacement with reduction (47.9%). A total of 73% of the individuals had experienced headaches in the previous 12 months. The majority of the participants described the headache episodes as occurring less than 7 days/month and lasting less than 4 hours. Among people with painful TMD, the frequency of headaches was almost twice as high as that in nondisordered individuals (48.35% and 25.35%, respectively; P < .0001). The logistic regression model confirmed a significant overlap between headache and painful TMD (OR = 4.77, 95% CI 2.44-9.32, P = .0000). For the entire studied population, no statistically significant connections were established between the occurrence of identified TMJ disorders and headache reports or diagnoses (P > .05).

CONCLUSION

Headaches and pain-related TMD are major problems among the Polish urban population. Headache was a much more frequent problem for participants with painful TMD. This issue requires further research and identification of cause-and-effect relationships. Considering the entire studied population, the relationship between identified TMJ disorders and headache is negligible.

Complete rehabilitation of patients with bruxism by veneered and non-veneered zirconia restorations with an increased vertical dimension of occlusion: an observational case-series study

PURPOSE

To assess the clinical performance of the complete rehabilitation of a series of patients with bruxism treated by teeth- and implant-supported veneered and non-veneered zirconia restorations with an increased vertical dimension of occlusion (VDO).

METHODS

Ten patients with bruxism, aged 62-70 years, were treated with 108 veneered and 142 non-veneered zirconia restorations and attended the recall appointment. The mean observation period was 28.2 (±16.8) months. The patients were identified from records, and clinical details were retrieved from their files. In the recall appointment, the restorations were evaluated using modified California Dental Association (CDA) criteria. The periodontal probing depth, bleeding index, presence of caries and implant survival and success rate were recorded.

RESULTS

No biological complications were recorded for any restorations. The success and survival rate of all implants was 100%. The overall mean survival and success rate of all restorations was 99.6%. In the veneered group, the predominant complication was minor veneer chipping (13.9%) on the incisal edge, which required only polishing (grade 1); in the non-veneered group, the predominant failure was open proximal contacts between the implant restoration and adjacent teeth (9%); only one implant restoration needed repair. One restoration was replaced due to a horizontal tooth fracture.

CONCLUSIONS

Within the limitations of this study, we conclude that the survival and success rate of monolithic zirconia restorations installed in patients with bruxism was excellent, although the veneered zirconia restorations showed a high rate of minor veneer chipping, which required only polishing.

Sleep Bruxism and Occurrence of Temporomandibular Disorders-Related Pain: A Polysomnographic Study

Introduction: The diagnosis of sleep bruxism is challenging due to the difficulties involved. Sleep bruxism can lead to clinical consequences, including pain in masticatory muscles, limitation of jaw mobility, headache, and the spectrum of symptoms associated with damage to the teeth and oral mucosa. Currently, only video-polysomnography can definitely diagnose sleep bruxism. Due to the risk of painful temporomandibular disorders (TMD) in sleep bruxers, early diagnosis of pain in the temporomandibular region using questionnaires is recommended. Therefore, this study aimed to assess the relationship between the intensity of sleep bruxism and the occurrence of pain related to TMD.

Materials and Methods: This study was conducted on the patients of the Clinic of Prosthetic Dentistry operating at the Department of Prosthetic Dentistry at the Wroclaw Medical University. Based on a positive medical history, a thorough examination for the diagnosis of probable sleep bruxism was carried out in the enrolled patients. Eligible patients were then subjected to a video-polysomnographic study. Each patient was asked to complete the TMD Pain Screener questionnaire to assess the occurrence of pain in jaw and temple area.

Results: The results of the study showed that increased bruxism episode index (BEI) was statistically significantly correlated with increase of all types of bruxism episodes—phasic, tonic, and mixed—in all the studied patients; a significant correlation was also found with respect to division of patients into studied and control groups. The study also showed that there was no statistically significant difference between BEI values and scores of TMD Pain Screener. In all the studied patients, a higher BEI was not found to be correlated with the occurrence of TMD-related pain assessed by TMD Pain Screener; similarly, no correlation was found with respect to division of patients into studied and control groups.

Conclusions: The occurrence of TMD-related pain is not related to the intensity of sleep bruxism. TMD Pain Screener may be used as an auxiliary tool in the diagnosis or risk of occurrence of TMD-related pain, whereas in the case of sleep bruxism, it has only limited diagnostic value.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT03083405

International consensus on the assessment of bruxism: Report of a work in progress

In 2013, consensus was obtained on a definition of bruxism as repetitive masticatory muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible and specified as either sleep bruxism or awake bruxism. In addition, a grading system was proposed to determine the likelihood that a certain assessment of bruxism actually yields a valid outcome. This study discusses the need for an updated consensus and has the following aims: (i) to further clarify the 2013 definition and to develop separate definitions for sleep and awake bruxism; (ii) to determine whether bruxism is a disorder rather than a behaviour that can be a risk factor for certain clinical conditions; (iii) to re-examine the 2013 grading system; and (iv) to develop a research agenda. It was concluded that: (i) sleep and awake bruxism are masticatory muscle activities that occur during sleep (characterised as rhythmic or non-rhythmic) and wakefulness (characterised by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible), respectively; (ii) in otherwise healthy individuals, bruxism should not be considered as a disorder, but rather as a behaviour that can be a risk (and/or protective) factor for certain clinical consequences; (iii) both non-instrumental approaches (notably self-report) and instrumental approaches (notably electromyography) can be employed to assess bruxism; and (iv) standard cut-off points for establishing the presence or absence of bruxism should not be used in otherwise healthy individuals; rather, bruxism-related masticatory muscle activities should be assessed in the behaviour's continuum.

Self-Reported bruxism and associated factors in Israeli adolescents

Little is known about the epidemiological characteristics of sleep and awake bruxism (SB and AB) in adolescents. The aims of the study were: to assess the prevalence rates of self-reported SB and AB in Israeli adolescents; to determine the associations between SB/AB and several demographical, exogenous and psychosocial factors in Israeli adolescents; and to investigate the possible concordance between SB and AB. The study made use of a questionnaire. The study population included 1000 students from different high schools in the centre of Israel. Prevalence of self-reported SB and AB in the Israeli adolescents studied was 9·2% and 19·2%, respectively. No gender difference was found regarding the prevalence of SB and AB. Multiple variable regression analysis revealed that the following predicting variables were related to SB: temporomandibular joint sounds (P = 0·002) and feeling stressed (P = 0·001). The following predicting variables were related to AB: age (P = 0·018), temporomandibular joint sounds (P = 0·002), oro-facial pain (P = 0·006), and feeling stressed (P = 0·002) or sad (P = 0·006). A significant association was found between SB and AB; that is, an individual reporting SB had a higher probability of reporting AB compared with an individual who did not report SB (odds ratio = 5·099). Chewing gum was the most common parafunction reported by adolescents. The results of this study demonstrate that self-reports of AB and SB are common in the Israeli adolescents population studied and are not related to gender. The significant correlation found between SB and AB may be a confounding bias that affects proper diagnosis of bruxism through self-reported questionnaires only.

The association between dental wear and reduced vertical dimension of the face: a morphologic study on human skulls

OBJECTIVE

The aim of this study was to explore the relationship between dental wear and facial morphology, with particular reference to the occlusal vertical dimension, in modern human skulls.

DESIGN

One hundred and three skulls (52 men and 51 women) between the ages of 20 and 50+ years old were studied. The selected skulls were from a modern period (the 17th and the 18th centuries) and included at least one entire condyle and had at least 3 posterior teeth (premolar or molar) in each quadrant to allow for dental articulation. Occlusal wear was evaluated using ordinal scale (0-4) and vertical occlusal dimension was evaluated by measuring upper facial height (UFH), lower facial height (LFH), LFH-to-UFH ratio (L-U-R) and dental wear. Based on the occlusal wear score, two groups were defined: with and without significant wear.

RESULTS

Significant relation was observed between age and dental wear (P<0.01). No significant differences were found in the LFH (P=0.847) or UFH (P=0.108) between the two wear groups. In addition, no significant difference (P=0.132) was demonstrated in the LFH-to-UFH ratio between the groups. No difference was observed in the dental wear score between genders (P=0.321).

CONCLUSION

Within its limitations, this study demonstrated that dental wear does not influence the vertical dimension of occlusion. Our assumption is that the dento-facial complex fully compensates for the dental effects of wear throughout life.

Prevalence of sleep bruxism in children: a systematic review of the literature

The aim of the present investigation was to perform a systematic review of the literature dealing with the issue of sleep bruxism prevalence in children at the general population level. Quality assessment of the reviewed papers was performed to identify flaws in the external and internal validity. Cut-off criteria for an acceptable external validity were established to select studies for the discussion of prevalence data. A total of 22 publications were included in the review, most of which had methodological problems limiting their external validity. Prevalence data extraction was performed only on eight papers that were consistent as for the sampling strategy and showed only minor external validity problems, but they had some common internal validity flaws related with the definition of sleep bruxism measures. All the selected papers based sleep bruxism diagnosis on proxy reports by the parents, and no epidemiological data were available from studies adopting other diagnostic strategies (e.g. polysomnography or electromyography). The reported prevalence was highly variable between the studies (3·5-40·6%), with a commonly described decrease with age and no gender differences. A very high variability in sleep bruxism prevalence in children was found, due to the different age groups under investigation and the different frequencies of self-reported sleep bruxism. This prevented from supporting any reliable estimates of the prevalence of sleep bruxism in children.

Bruxism defined and graded: an international consensus

To date, there is no consensus about the definition and diagnostic grading of bruxism. A written consensus discussion was held among an international group of bruxism experts as to formulate a definition of bruxism and to suggest a grading system for its operationalisation. The expert group defined bruxism as a repetitive jaw-muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. Bruxism has two distinct circadian manifestations: it can occur during sleep (indicated as sleep bruxism) or during wakefulness (indicated as awake bruxism). For the operationalisation of this definition, the expert group proposes a diagnostic grading system of 'possible', 'probable' and 'definite' sleep or awake bruxism. The proposed definition and grading system are suggested for clinical and research purposes in all relevant dental and medical domains.

Masticatory muscle disorders diagnostic criteria: the American Academy of Orofacial Pain versus the research diagnostic criteria/temporomandibular disorders (RDC/TMD)

In this study, relevant cases were retrospectively reviewed to identify patients who were diagnosed as suffering from myofascial pain only according to the research diagnostic criteria/temporomandibular disorders (RDC/TMD) criteria, in order to examine whether or not they could fulfil the American Academy of Orofacial Pain (AAOP) diagnostic criteria for TMD-related masticatory muscle disorders. One hundred and twenty-seven patients, diagnosed according to the RDC/TMD criteria as having myofascial pain with or without limited jaw opening only, were allocated to two groups according to their answers to the RDC/TMD 'jaw disability checklist'. The two groups were compared for Axis I and II data taken from the RDC/TMD questionnaire. Thirty-eight of the patients (29·9%) did not associate their symptoms with jaw functions (e.g. chewing and yawning). This group was characterised by increased range of motion (ROM) and older average age. The AAOP diagnostic criteria for TMD require pain on function in all subtypes of TMD-related muscle disorders. An association between pain and jaw function is common and research is needed to determine whether this should be categorised differently to muscle pain unrelated to jaw function. There may well be different pathophysiological mechanisms and consequently different management strategies for these two pain conditions.

Self-reported bruxism and temporomandibular disorders: findings from two specialised centres

The aims of this investigation were to report the frequency of temporomandibular disorders (TMD) diagnoses and the prevalence of self-reported awake and sleep bruxism as well as to describe the possible differences between findings of two specialised centres as a basis to suggest recommendations for future improvements in diagnostic homogeneity and accuracy. A standardised Research Diagnostic Criteria for TMD (RDC/TMD) assessment was performed on patients attending both TMD Clinics, viz., at the University of Padova, Italy (n=219; 74% women) and at the University of Tel Aviv, Israel (n=397; 79% women), to assign axis I physical diagnoses and to record data on self-reported awake and sleep bruxism. Significant differences were shown between the two clinic samples as for the frequency of TMD diagnoses (chi-square, P<0·001) and the prevalence of at least one positive response to bruxism items (chi-square, P<0·001). The more widespread use of TMJ imaging techniques in one clinic sample led to a higher prevalence of multiple diagnoses, and the higher prevalence of self-reported bruxism in patients with myofascial pain alone described in the other clinic sample was not replicated, suggesting that the different adoption of clinical and imaging criteria to diagnose TMD may influence also reports on their association with bruxism. From this investigation, it emerged that the features of the study samples as well as the different interpretation of the same diagnostic guidelines may have strong influence on epidemiological reports on bruxism and TMD prevalence and on the association between the two disorders.

Bruxism, oral parafunctions, anamnestic and clinical findings of temporomandibular disorders in children

The reported prevalence of temporomandibular disorders (TMD) present during childhood and adolescence ranges between 7% and 68%. The range of the reported prevalence of sleep bruxism in children is also wide. The purpose of the current study was threefold: (i) determine the prevalence of oral parafunctions, sleep bruxism and of anamnestic and clinical findings of TMD among Israeli children with primary or mixed dentition; (ii) to establish whether the parafunctional activities are associated with anamnestic and clinical findings of TMD in this population and (iii) to examine the possible impact of stressful life events on the prevalence of bruxism, oral parafunctions, and anamnestic and clinical findings of TMD in children. A total of 244 children (183 girls and 61 boys) aged 5-12 years were included in the study. Each participant underwent a full TMD examination. Parents, in collaboration with their children, completed a questionnaire on TMD symptoms, oral parafunctions and stressful life events in their children's life. Most participants (78·8%) reported at least one oral habit. Of these, only 'jaw play' was associated with TMD anamnestic and clinical findings. Stressful life events were associated only with the performance of multiple oral habits. These findings indicate that the performance of oral parafunctions is commonplace during childhood, with younger children exhibiting fewer oral parafunctions than adolescents. Stressful life events are related with an increase in the performance of multiple oral parafunctions in children but the later are not necessarily associated with anamnestic and clinical findings of TMD in the paediatric population.

Classifying degenerative joint disease by the RDC/TMD and by panoramic imaging: a retrospective analysis

The purposes of the study were to evaluate the utility of diagnosing degenerative joint disease (DJD) by the clinical finding of coarse crepitus alone, without supporting imaging studies, as defined by the RDC/TMD, and to evaluate the contribution of panoramic radiography as an aid in the diagnosis of DJD. A retrospective analysis of 372 consecutive patients with TMD was conducted. Their panoramic radiographs were evaluated for the extent of their contribution to the final diagnosis. Panoramic radiography was of no diagnostic value in 94.4% of the cases when the group was considered as a whole. When patients diagnosed with DJD were considered separately, panoramic radiography was completely sufficient for reaching the final diagnosis in 20.0% of the cases. In almost 90% of these patients, however, the clinical examination did not support the diagnosis of DJD (no coarse crepitus was found). This raises some doubts about the effectiveness of the clinical examination according to the RDC/TMD and about the utility of panoramic radiography in the definitive diagnosis of DJD, because both techniques have low accuracy (11.1% and 20%, respectively). The present study supports the current recommendations that panoramic radiography should not be ordered routinely to assess DJD, but still it is first choice when any dental problem is suspected. Further additional imaging (computerized tomography, magnetic resonance imaging) should be considered only if there is reason to expect that the findings might affect diagnosis and management. This study adds to recent criticisms of the clinical validity of the RDC/TMD, with regard to DJD.

[Severe limitation of mouth opening]

Limitation of mouth opening is a common source of referral to an orofacial pain clinic with a proposed diagnosis of Temporomandibular Joint Dysfunction (TMD). The word "trismus" is defined by the American academy of orofacial pain as: "Myospasm of masticatory muscles specifically causing limited jaw opening; early symptom of tetanus". Therefore, once trismus is suspected, TMD should be ruled out. However, it is not uncommon to find the usage of this term to describe severe limitation of opening by causes other than myospasm, therefore posing the risk of misdiagnosis. The purpose of this article is to describe the differential diagnosis of hard end limitation of opening with emphasis on the clinical tools used to differentiate between muscle source of hard end limitation and other sources of hard end limitation. Several cases of hard end limitation of mouth opening are presented and through them major principles of orofacial diagnosis are discussed.

[Do temporomandibular disorders really exist?]

Temporomandibular Disorders (TMD) is a collective term embracing a number of clinical problems that involve the muscles of mastication, the temporomandibular joint (TMJ) and associated structures or both. This group of disorders has been identified as the chief cause of pain, which is not of dental origin, in the orofacial area, and is defined as a subgroup in the category of musculoskeletal disorders. These disorders impair the quality of life of those suffering from them due to the extent of the pain and the chronic nature of its symptoms. It is known that chronic pain causes the development of psychological disturbances (anxiety, depression, etc.). The most common symptoms of TMD are the pain that usually appears as the result of mandibular activity (speaking or chewing), and is usually located in the masticulatory muscles, in the preauricular area and the temporomandibular joint (TMJ). Additional common symptoms are: a. restriction in jaw movement; b. asymmetry in jaw movement; c. noises from the joint. Patients suffering from TMD are likely to exhibit additional symptoms: hypertrophy of the muscles of mastication (an adaptive and asymptomatic phenomenon), abnormal occlusar erosion due to nighttime or daytime bruxism, or teeth grinding. Most functional temporomandibular disorders have similar signs and symptoms. As a result, diagnosis of the various disorders presents a serious problem. Functional temporomandibular disorders are often accompanied by mental symptoms such as depression, anxiety and/or somatization on various levels. One of today's accepted methods of classification also refers to the mental aspect and thus enables, for the first time, a suitable scientific comparison of the epidemiological, diagnostic and treatment data in the various studies. This method, initiated by Dworkin and LeResche (1992) is known as Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The purpose of this method is to classify every subgroup of TMD according to agreed upon, clear and measurable diagnostic criteria, both from the physical (AXIS I) and the mental (AXIS II) aspect. The method includes a scale which grades the extent of severity, damage and limitations caused by the illness, in a manner which now can make scientific comparisons between the various studies and between the population of patients and the general population. Temporomandibular disorders are very common and affect between 30%-50% of the population, and appear to be more prevalent among women than among men. Studies conducted on youth revealed significant relationships between oral parafunctions (especially chewing gum and "jaw playing"), and functional temporomandibular disorders. The significance of this finding is in the need to warn young people of the possible risks of engaging in intensive oral practices. The high prevalence of signs and symptoms among the Israeli population obligates us, in our opinion, to change the physical examination for identification of these disorders, to a routine procedure in all dental clinics in Israel.

Effect of stabilization splint therapy on pain during chewing in patients suffering from myofascial pain

Masticatory myofascial pain (MFP) condition is a musculoskeletal disorder that compromises the functional capacities of the masticatory system. As such, the incorporation of an intensive chewing test as a discriminatory exercise for the diagnosis of this condition and evaluation of treatment success has considerable potential. Various splint designs have been used successfully, which have posed a question of whether the therapeutic effect of the splint is a placebo or has some other curative properties. The purpose of this study was to evaluate the efficacy of the stabilization appliance to reduce signs and symptoms in MFP patients and to compare the pain experience during the chewing test between two groups of patients, with and without splints. Myofascial pain patients (n = 37) who reported exacerbation of pain in function participated in the study. Patients perfomed a 9-min chewing test, followed by 9-min rest and marked their pain intensity on a visual analogue scale every 3 min. Of the 37 patients, 21 received a stabilization flat occlusal splint for night use and 16 were equally monitored clinically without a splint. At the end of 8 weeks, a second clinical examination and chewing test were performed. Student's t-test was used to analyse differences between study groups. Analysis of variance and covariance (ancova) with repeated measures was applied to analyse the effect of treatment. Level of pain at baseline prior to the chewing test (P0) was introduced as a co-variant. At baseline both groups showed relatively high scores of pain intensity and did not show any significant differences among the collected variables. At the end of the experiment, the splint group had a statistically significant reduction in pain intensity, in mean muscle sensitivity to palpation and in the pain experience during the chewing test compared with no change in the controls. A stabilization splint has a therapeutic value beyond its placebo effects. Thus, it should be an integral part of the treatment modalities in MFP disorder patients. An intensive chewing test is an effective tool to evaluate the treatment modality efficacy in MFP patients.

Oral motor parafunctions among heavy drug addicts and their effects on signs and symptoms of temporomandibular disorders

AIMS

To investigate the prevalence of temporomandibular disorders (TMD), bruxism, and other oral habits among drug addicts compared to a normal, non-addicted, matched control population, and to assess the detrimental effect of long-term drug abuse on the parameters studied.

METHODS

Subjects included 55 drug-addicted patients (51 males and 4 females) randomly selected from long-term addicts using "hard" narcotics and attending a methadone maintenance center and a control group of 52 normal non-addicted individuals (48 males and 4 females) matched to the addicts for age, gender, and socioeconomic status. A clinical examination and a questionnaire were used. One examiner determined that all questions were correctly understood and answered, and a second examiner performed the clinical examinations and was unaware of the results of the questionnaire.

RESULTS

The addicted group had a high prevalence of orofacial motor behavior (bruxing, clenching) as well as signs and symptoms of TMD (morning headache, joint noises, joint and masticatory muscle tenderness to palpation, and tooth wear) compared to the controls. Active (voluntary) jaw opening was significantly smaller, although within an acceptable range when compared to the controls.

CONCLUSION

Long-term drug abuse detrimentally affects the stomatognathic system, as expressed in a high prevalence of oral motor behavior and signs and symptoms of TMD.

Oral habits among adolescent girls and their association with symptoms of temporomandibular disorders

AIM

To evaluate the contribution of certain parafunctional activities to the presence of temporomandibular disorder (TMD) symptoms among teenage girls, with special emphasis to gum chewing and jaw play.

METHODS

A total of 323 girls, aged 15-16 years, were randomly selected from a religious junior high school. The girls responded to a questionnaire on oral habits and TMD symptoms.

RESULTS

Gum chewing was a very prevalent habit (62.4%), performed daily (mean chewing time 3.95 h day-1). Girls who chewed intensively (more than 4 h day-1) showed associations with pain in the ear area during function and at rest, as well as with joint noises. Jaw play, although reported by only 14.3%, was significantly associated with pain in the ear area during function and at rest, feeling of tiredness of the jaw while chewing, joint noises, catch and lock. All oral parafunctions, except chewing gum, were associated with jaw play and with each other.

CONCLUSIONS

Jaw play was the most detrimental habit in TMD; intensive gum chewing was a potentially contributing factor for joint noises and pain. Oral parafunctions (except chewing gum) were significantly associated between themselves and suggest a behavioural pattern of "jaw hyperactivity".

Topical application of capsaicin for the treatment of localized pain in the temporomandibular joint area

AIMS

To determine the effectiveness of topical capsaicin cream application on localized pain in the temporomandibular joint (TMJ) area.

METHODS

A randomized, double-blind, placebo-controlled study was conducted on 30 patients suffering from unilateral pain in the TMJ area. Patients were randomly divided into experimental and placebo groups; they were instructed to apply 0.025% capsaicin cream or its vehicle to the painful TMJ area 4 times daily for 4 weeks. Subjective parameters of present pain, most severe pain, effect of pain on daily activities, and pain relief were assessed each week on a visual analog scale. Muscle and joint sensitivity to palpation on the painful and contralateral joints and maximal mouth opening (assisted/passive and non-assisted/active) were examined weekly by the same experienced examiner.

RESULTS

Capsaicin cream produced no statistically significant influence on measured variables when compared to placebo. Both experimental and placebo groups showed statistically significant improvement in most variables during the experiment.

CONCLUSION

The factor of time had a major effect in the non-specific improvement of the parameters assessed. The placebo effect played an important role in the treatment of patients with pain in the TMJ area.

Splints and stress transmission to teeth: an in vitro experiment

OBJECTIVE

To determine the influence of hard and soft splints with two thicknesses on the stress transmission to the tooth supporting the splint and the opposite tooth.

METHODS

Continuous vertical forces up to 500N were applied to two opposite first molar phantom teeth using a universal loading machine. Deformation was detected by strain gauges attached to the cervical area of the buccal and lingual aspects of the lower tooth. Strain, as a function of force, was collected and the slope, defined as the compliance (in microS/N) of the system, was calculated.

RESULTS

The highest compliance was found with hard splints. When splints were constructed on the upper molar, the highest compressive compliance was registered on the buccal side (2.8 microS/N) and tension compliance on the lingual side (-0.35 microS/N). When constructed on the lower tooth, the opposite was found. Soft splints resulted in compression on both the buccal and lingual sides when adjusted to the upper or lower tooth. A higher compliance was found on the buccal side (1.26 microS/N), while on the lingual side, the values varied (0.48-0.78 microS/N).

CONCLUSIONS

Soft splints are more efficient in protecting teeth against the damage of bending forces although there is an increase of compression forces. The tooth opposing a hard splint is exposed to a higher risk of bending forces.

Generalized joint laxity and its relation with oral habits and temporomandibular disorders in adolescent girls

A group of 248 girls, aged 15-16 years, were randomly selected and examined both clinically and by questionnaire with regard to the signs and symptoms of temporomandibular disorders (TMD), generalized joint laxity (GJL), range of mandibular opening, temporomandibular joint (TMJ) hypermobility and presence of oral parafunctions. The prevalence of GJL was 43% and that of TMJ hypermobility (TMJH) was 27.3%. A significant, albeit weak, correlation was found between the two. In the presence of joint click, both active and passive opening were significantly larger. When either muscle or joint sensitivity to palpation was present, the difference between the active and passive range of mouth opening increased significantly. The presence of reported clicks was negatively associated with GJL. This association was not valid in the presence of parafunction. Some of the signs and symptoms of TMD affected the range of mouth opening. In the presence of joint clicks, the mean active and passive mandibular opening were significantly larger. In the presence of joint and muscle sensitivity to palpation, the difference between passive and active mouth opening was larger. This was possibly because of the effect of pain on the full active range of opening, which was invalid in the registration of the passive mandibular opening. GJL, when present, did not seem to jeopardize the health of the stomatognathic system as expressed in the signs and symptoms of TMD. There was a negative association between GJL and the presence of reported joint clicks and catch. When a parafunction was present in addition to GJL, this association was invalid but not reversed, as has been previously reported.

Oral habits and their association with signs and symptoms of temporomandibular disorders in adolescent girls

A group of 248 randomly selected high school girls, aged 15-16 years, completed a questionnaire and were examined clinically with regard to various oral habits and signs and symptoms of temporomandibular disorders (TMD). Common habits reported in the literature, such as gum chewing, nail biting, biting foreign objects, clenching and bruxism, eating seeds and crushing ice, as well as two less reported habits, 'jaw play' and continuous arm leaning, were evaluated. The most outstanding finding was the high prevalence and intensity of gum chewing among our study group: 92% of the girls chewed daily and 48% chewed gum for more than 3 h a day (intensive gum chewing). Statistically significant associations were found between intensive gum chewing and muscle sensitivity (P<0.001) and joint noises (P<0. 05), and between crushing ice and muscle sensitivity to palpation (P<0.005). A positive association was found between 'jaw play' and joint disturbances: reported joint noises (P<0.01), catching of the joint (P<0.01) and joint tension (P<0.001). A positive association was also found between arm leaning and reported joint noises (P<0. 05), catching (P<0.05), and joint tension (P<0.005). There was no association between the presence of bruxism and muscle sensitivity to palpation or joint disturbances. The potential harmful effects of intensive gum chewing, 'jaw play', continuous arm leaning and ice crushing are presented in this study. In light of these findings, the professional community should address these habits with proper data gathering, examination and consultation.