Awareness of tooth grinding and clenching from adolescence to young adulthood: a nine-year follow-up

Self-reported sleep bruxism in 1990 and 2011 in a nationwide twin cohort: Evidence of trait persistence and genetic liability

BACKGROUND

Due to different assessment modes employed, a clear picture of the prevalence of sleep bruxism across time cannot be formed. Moreover, studies on the persistent or fluctuating nature of sleep bruxism have yielded divergent and even contradictory results. The aim of the present study was to evaluate in a nationwide twin cohort whether self-reported sleep bruxism was correlated longitudinally, pairwise and cross-twin over a 20-year period.

OBJECTIVES

Self-reported bruxism was assessed in 1990 and 2011 by mailed questionnaires in the Finnish Twin Cohort study of same-sex twins born 1945-1957.

METHODS

We assessed the phenotypic stability over time for all participating individuals (n = 4992). Among zygosity verified pairs (n = 516 MZ and n = 837 DZ), we estimated the cross-sectional zygosity correlations and the zygosity-specific cross-twin cross-time correlations.

RESULTS

Reported bruxism appeared rather persistent over time without significant difference regarding zygosity. The overall phenotypic longitudinal correlation was 0.540 and somewhat higher in men (0.596) than in women (0.507). Pairwise trait correlations in 1990 and 2011 were higher in MZ than in DZ pairs. The cross-twin cross-time correlations were higher in MZ twins than in DZ twins, but less than the cross-sectional MZ and DZ pairwise correlations.

CONCLUSIONS

The higher correlation of reported sleep bruxism in the cross-twin cross-time analyses in MZ than in DZ pairs implies a genetic background for bruxism persistence. Also, bruxism over time in individual twins appears to be fairly persistent and somewhat higher in men than women.

Sleep bruxism in children and adolescents-A scoping review

BACKGROUND AND OBJECTIVE

This review paper focuses on sleep bruxism (SB) in children and adolescents. It aims to assess the landscape of knowledge published in the last 20 years.

METHODS

A total of 144 relevant publications from 386 previously identified through Medline were included, of which 83 were on possible SB, 37 on probable SB, 20 on definite SB and 4 were non-applicable. The review places emphasis on the recent evidence on prevalence, pathophysiology, diagnosis and management of SB in children and adolescents, with special focus on probable and definitive SB.

RESULTS

The prevalence ranges from 5% to 50% depending on the age range and on the SB diagnosis (possible, probable or definitive). The pathophysiology is multifactorial, arousal associated and with behavioural problems and sleep disorders (obstructive sleep apnoea, snoring, nightmares) as risk factors, as well as respiratory conditions (allergies, oral breathing). Screening should include questionnaires and dental assessment. Instrumental recording is helpful to confirm diagnosis although more studies are needed to validate this approach in children. SB management includes controlling orofacial and dental consequences and assessing for any other comorbidity. Management options include occlusal splints, oral appliances (advancement mandibular), rapid maxillary expansion and some medications, although this last option is supported by limited evidences in children.

CONCLUSION

Suggestions of future topics in research are delivered to better understand comorbidities, diagnosis and management with improved outcomes compared to what is currently available.

Self-reported sleep bruxism and mortality in 1990-2020 in a nationwide twin cohort

BACKGROUND

The association of sleep bruxism with mortality has not been studied.

OBJECTIVES

Altogether 12 040 subjects from the nationwide Finnish twin cohort were included in the analyses. We examined whether self-reported sleep bruxism is associated with increased risk of mortality, and if so, whether the effect is independent of known common risk factors. The time span of the follow-up was 30 years.

METHODS

Cox proportional hazards regression models (Hazard Ratios and their 95% Confidence Intervals) adjusted by age, sex and covariates were used to assess the effect of baseline bruxism status in 1990 on future mortality in 1990-2020.

RESULTS

The risk of mortality among all participants (n = 12 040), independent of missing covariates and adjusted by age and sex, was 40% higher in weekly bruxers than in never bruxers (HR 1.40, 95% CI 1.16-1.68, p < .001). However, when adjusted by all studied covariates, (n = 11 427) the risk was no longer observed (HR 1.04, 95% CI 0.86-1.25, p = .717). Despite the overall lack of between bruxism and mortality after adjustment for covariates, we examined the cause-specific risks for major cause-of-death groups. There were no substantial associations of weekly bruxism with major disease outcomes by the fully adjusted hazard ratios for them.

CONCLUSION

Bruxism does not kill-in line with its definition of being rather a behaviour (with all its phenotypes) than a disease.

Nutrients Associated with Sleep Bruxism

Background: The purpose of the present research was to identify nutrients related to sleep bruxism and to establish a hypothesis regarding the relationship between sleep bruxism and nutrients. Methods: We recruited 143 Japanese university students in 2021 and assigned them to sleep bruxism (n = 58) and non-sleep bruxism groups (n = 85), using an identical single-channel wearable electromyography device. To investigate nutrient intakes, participants answered a food frequency questionnaire based on food groups. We assessed differences in nutrient intakes between the sleep bruxism and non-sleep bruxism groups. Results: Logistic regression modeling showed that sleep bruxism tended to be associated with dietary fiber (odds ratio, 0.91; 95% confidence interval, 0.83–1.00; p = 0.059). In addition, a subgroup analysis selecting students in the top and bottom quartiles of dietary fiber intake showed that students with sleep bruxism had a significantly lower dietary fiber intake (10.4 ± 4.6 g) than those without sleep bruxism (13.4 ± 6.1 g; p = 0.022). Conclusion: The present research showed that dietary fiber intake may be related to sleep bruxism. Therefore, we hypothesized that dietary fiber would improve sleep bruxism in young adults.

Wear Management of Colored Foils for the Assessment of Sleep Bruxism Patterns-A Prospective, Randomized Crossover Study

The assessment of bruxism relies on clinical examinations, questionnaires, and polysomnography. The additional use of colored foils (BruxChecker^®) could enable a more precise evaluation of bruxing patterns. To assess differences between use of the foils during stress periods or just on consecutive nights and to determine a reasonable duration of using the foils, 28 patients were classified according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and were randomly assigned to wearing the 12 foils for six consecutive nights (alternately in the upper and lower jaw; "consecutive") or six nights within one month following days of high stress ("stress") in a crossover design. The sizes of the attrition areas were measured with ImageJ. Stress was evaluated using the Perceived Stress Scale. The Stress Coping Questionnaire (SVF-120) was used for assessing habitual stress coping strategies. Areas of attrition increased significantly from day 1/2 to 5/6, both for the upper and lower jaw. Molars in the mandible had significantly larger attrition areas than in the maxilla. No significant differences were detected between "consecutive" and "stress" phases. The foils were suitable for differentiating teeth more or less affected by bruxism and were able to show that areas of attrition increased with days, indicating that some adaptation takes place and several days of wearing the foils are required to show the full picture. However, no differences between low/moderate- and high-stress phases were detected.

Investigating the effect of bruxism on maxillary arch length and width in children using three-dimensional digital model analysis

Background

Bruxism is defined as repetitive jaw-muscle activity characterized by the grinding and clenching of teeth. The prevalence of bruxism in children is extensive, and it can cause irregularities in dental arches. The study aimed to investigate the presence of any effects of bruxism on maxillary arch length and width in children using three-dimensional (3D) digital model analysis.

Method

This study evaluated 30 children with bruxism. For every child with bruxism, a case control without bruxism was selected and matched for gender, age, and dentition. Digital models of the patients’ maxilla were obtained with a 3D intraoral scanner, and width and length measurements between the reference points on the maxilla were obtained on the digital models.

Results

The mean age of the study group was 9.13 ± 1.27. Insıgnificance differences were found between females and males within and between groups in terms of maxillary width and length. Insignificant difference was found between the control and study groups when the lengths of 3R-3L, 4R-4L, 5R-5L, 6R-6L, and IP-M were compared (p > 0.05).

Conclusion

Based on the study results, there were no differences in the maxillary arch length and width in patients with bruxism and patients without bruxism.

The Epidemiology of Bruxism in Relation to Psychological Factors

The aim of the present study was to establish the prevalence of sleep/awake bruxism among young students in Transylvania and to correlate the presence of this muscle activity with behavioral variations. This analytical, observational, cohort, cross-sectional, and prospective study involved 308 volunteers aged between 19 and 30 years of different nationalities, all students of the “Iuliu Hațieganu” University of Medicine and Pharmacy in Cluj-Napoca, Romania. Subjects were asked to complete an anonymous questionnaire which was structured in five sections. The results obtained from the questionnaires were analyzed separately for sleep bruxism and for awake bruxism. We did not find any statistically significant correlation between awake bruxism or sleep bruxism and age (p = 0.30 and p = 0.37, respectively), sex (p = 0.44 and p = 0.48, respectively), or nationality (p = 0.55 and p = 0.67, respectively). Only a high degree of stress and frustration (p = 0.035 and p = 0.020) was observed in European subjects except for the Romanians and the French, likely related to the difficulties of adapting to the language and lifestyle in Romania. Female sex was statistically significantly associated with an increased level of stress (p = 0.004), duty-related depression (p = 0.006), and duty-related anxiety (p = 0.003). Stress and anxiety can be favorable factors in the appearance of both types of bruxism; however, depression is associated only with awake bruxism.

Association between possible awake bruxism and bullying among 8- to 11-year-old children/adolescents

BACKGROUND

Bruxism is characterized by tooth grinding and/or clenching.

AIM

To evaluate the association between possible awake bruxism (PAB) and bullying among individuals aged 8-11 years.

DESIGN

A representative cross-sectional study was conducted with 434 eight- to eleven-year-old children/adolescents. Parents/caregivers answered a questionnaire to provide data on sociodemographic characteristics. Children/adolescents answered a questionnaire about the occurrence of PAB. The Olweus Bully/Victim Questionnaire was used. The Poisson regression analysis was performed.

RESULTS

Of the 434 children/adolescents, 209 (48.2%) were boys and 225 (51.8%) were girls. The mean age of the children/adolescents was 9.14 years (±1.00). Children/adolescents who were victims of bullying (PR = 1.52, 95% CI = 1.14-2.04, P = .005) and bullies-victims (PR = 2.08, 95% CI = 1.36-3.17, P = .001) presented a higher frequency of PAB than those who were not involved in bullying.

CONCLUSION

Children/adolescents who were bullying victims and bullies-victims had a higher frequency of PAB.

Association of facial type with possible bruxism and its related clinical features in adolescents: A cross-sectional study

OBJECTIVES

The assessment of bruxism and its clinical characteristics is acknowledged in literature. This study aimed to evaluate the association of adolescents' facial patterns with bruxism and its related clinical features in the form of signs and symptoms.

MATERIALS AND METHODS

Four hundred and three adolescents answered a questionnaire evaluating sleep bruxism (SB) and awake bruxism (AB). Parents/caregivers answered a questionnaire evaluating the adolescents' sleep features (drooling on the pillow, snoring). Adolescents' facial (dolichofacial/brachyfacial/mesofacial) and clinical features (pain in masseter/temporal muscle, indentations marks on the tongue, linea alba, tooth attrition, mouth's maximum opening and masseter electrical activity) were evaluated. Multinomial regression was performed. Odds ratio (OR) and confidence intervals (CI) were provided.

RESULTS

Brachyfacial adolescents were less likely to present possible AB compared to mesofacials (OR=0.46, CI=0.21-0.98). Brachyfacial adolescents were more likely to present pain in the temporal muscle (OR=6.59, CI=2.18-19.87) and a higher number of posterior teeth with attrition (OR=1.25, CI=1.02-1.57) compared to mesofacials. Dolichofacial adolescents were more likely of not presenting pain in the masseter muscle (OR=2.23, CI=1.03-4.83), had a higher mouth's maximum opening (OR=1.43, CI=1.04-1.97), had a higher number of posterior teeth with attrition (OR=1.17, CI=1.00-1.37) and were more likely to drool on the pillow (OR=2.05, CI=1.15-3.67) compared to mesofacials. Dolichofacial adolescents were more likely of not presenting pain in the temporal muscle (OR=6.36, CI=2.30-17.54), to present themselves without marks on the tongue (OR=2.26, CI=1.09-4.69) and present a higher mouth's maximum opening (OR=2.09, CI=1.40-3.13) compared to brachyfacials.

CONCLUSION

Bruxism and its clinical features differ among dolichofacial, brachyfacial and mesofacial adolescents.

Occlusal Features and TMJ Clicking: A 30-Year Evaluation from a Cohort Study

Occlusal features that deviate from normative values have been historically considered risk factors for temporomandibular joint (TMJ) disorders. Nowadays, a putative association between dental occlusion and TMJ disorders remains controversial, with research findings on associations being inconsistent and inconclusive. We hypothesized that putative occlusal features identified during adolescence are associated with TMJ clicking later in life. The Dunedin Multidisciplinary Health and Development Study is a longitudinal birth cohort study investigation of 1,037 children (48.4% female) born in Dunedin, New Zealand, between April 1, 1972, and March 31, 1973, and assessed repeatedly since then. Associations between posterior crossbite, overbite, and overjet at age 15, as well as both self-reported and clinically assessed TMJ clicking sounds at age 45, were studied. Data were analyzed using multivariate logistic regression, after controlling for sex, emotional style, self-reports of tooth clenching and sleep bruxism, and history of orthodontic treatment. Self-reported and examiner-reported TMJ clicking at age 45 affected 18.3% and 23.8% of the study sample, respectively, and were not associated with the presence of a posterior crossbite or abnormal overjet/overbite values during adolescence. Self-reported history of tooth clenching and emotional style were associated with self-reported TMJ clicking later in life. In addition, there is a suggestion that high overbite during adolescence is negatively associated with TMJ clicking later in life. A history of orthodontic treatment was not associated with TMJ clicking. Abnormal occlusal features, such as posterior crossbite and high and low overjet/overbite in adolescence, are not associated with higher prevalence of TMJ clicking later in life. Personality also appears to influence self-reports of TMJ clicking later in life.

Is Otalgia be a symptom of anxiety in children?

One of the common causes of ear pain (Otalgia) in children is the pain felt in the temporomandibular region due to bruxism, usually accompanied by stress and anxiety. The diagnosis and treatment of anxiety at an early age will affect the future lives of children. Our aim in the study was to investigate the presence and subtypes of anxiety in children with otalgia due to bruxism. In our study, 86 children aged between 6 and 16 years old who had ear pain and whose pain and tenderness were detected in the temporomandibular joint area and 40 healthy children were included as the control group. The children in both study groups were administered the Spence Children's Anxiety Scale (SCAS) test by the clinical psychologist. There was no statistical correlation between the children with bruxism and normal children (p > 0.05). While anxiety rate was 82% in children with bruxism, this rate was found to be 12.5% in normal children, this result was also statistically significant (p < 0.01). According to the SCAS test, when the subscales of anxiety detected in children with bruxism were evaluated, According to the SCAS test, when the subscales of anxiety detected in children with bruxism were evaluated, it was observed that the performance anxiety was high in the 6-12 and 12-16 age group. However, obsessive symptoms were mostly observed in the 12-16 age group while separation anxiety was detected in children in the 6-12 age group.

Recording of bruxism events in sleeping humans at home with a smart instrumented splint

Objective: The aim of this paper is to report quantitative and qualitative characteristics of bruxism events recorded in sleeping humans with a new smart ambulatory system specifically designed to measure dental clenching and grinding forces. The device is wireless and rechargeable, which enables its use over extended periods.Methods: Thirty recordings were obtained from volunteer subjects who wore the device at home during 10 consecutive nights (Clinicaltrials.gov N° NCT03363204).Results: The recordings showed that the system was able to successfully monitor bruxism during 10 consecutive nights, allowing a quantitative (number, duration, intensity, distribution during the night), as well as a qualitative characterization of the bruxism events (clenching vs. grinding).Discussion: This system could offer new perspectives in the field of bruxism, either as a research tool for clinical studies or as a medical device for the ambulatory home-based monitoring of bruxism.

Assessment of the Pain, Stress and Emotional Factor Related to the Occurrence of Bruxism

Background/Aim: Bruxism is a parafunctional habit that has multiple etiology. Globally it is a widespread problem. The purpose of this study was to assess the presence of pain, stress and to understand the emotional factor and their relations to the occurrence of bruxism.

Material and Methods: For the purpose of this paper, 40 patients with partial edentuloissness and bruxism were treated prosthetically and with night dentures. They were assessed for the degree of the pain they feel and were given questionnaires for the level of stress they feel and for their psychological situation. The control group consisted of 40 patients who were not treated but were diagnosed with the same methods like the previous group.

Results: Patient feel pain from the consequences of bruxism, disregarding the statistical significance related to gender. Stress pays a major role as we live in a dynamic and demanding society. The more competitive and ambitious the person is the more there are possibilities for occurrence of bruxism. Emotions are a very complex matter that unconsciously can be connected to the presence of bruxism.

Conclusions: Besides prosthetic rehabilitation, sometimes a multidisciplinary approach is needed. Dentists should be aware of their role as psychiatrist and need to be educated of the principles of a patient’s analysis and of the cognitive behavioral therapy.

Prevalence of Temporomandibular Disorder in Turkish University Students: a Questionnaire Study

Background/Aim: Temporomandibular dysfunction (TMD) might influence any individual with different signs and symptoms irrespective of gender or age. The aim of this study is to assess the prevalence of TMD in Oral and Dental Health Program students of İstanbul University-Cerrahpaşa.

Material and Methods: This study include a sample of 486 students with age ranging from18 to 24 years. The presence and severity of TMD was evaluated using the Fonseca’s Anamnestic Index (FAI) and its questionnaire. The data were analysed using SPSS Version 22. The chisquare test was used to compare the data from different groups and to determine whether the differences were statistically significant.

Results: The results showed that a total of 47,53% of students had some degree of TMD and females were generally more affected than males. These degrees were as follows: 33,95 % were classified as mild, 11,52 % moderate and 2,05 % severe signs and symptoms. The women exhibited some degree of TMD (51,8%) at a higher frequency than men (40,33%). No significant differences were observed between gender for a same TMD severity degree (p>0.05).

Conclusions: A high prevalence of mild TMD was found in this study population. In addition, tense personalities, headaches, and temporomandibular joint (TMJ) sounds were the most prevalent findings of TMD. The present study suggests that Fonseca’s Anamnestic Index (FAI) has been used in screening for TMD for prevention and management of TMD in a non-patient young population.

Awake and Sleep Bruxism Among Israeli Adolescents

Introduction: Sleep and awake bruxism are potential risk factors for oral hard tissue damage, failure of dental restorations and/or temporomandibular disorders. Identifying the determinants of sleep and awake bruxism among adolescents will enable development of preventive interventions for those at risk.

Objectives: To determine emotional, behavioral and physiological associations of sleep and awake bruxism among Israeli adolescents.

Methods: Two thousand nine hundred ninety-three Israeli high school students, from five different high schools in Israel, were approached in the classroom and requested to complete online questionnaires on sleep and awake bruxism, emotional aspects, smoking, alcohol consumption, oral habits, facial pain, and masticatory disturbances. The final study sample concerning awake and sleep bruxism included 2,347 participants.

Results: 1,019 (43.4%) participants reported not experiencing any form of bruxism (neither sleep nor awake), 809 (34.5%) reported awake bruxism, 348 (14.8%) reported sleep bruxism and 171 (7.3%) reported both sleep and awake bruxism. Multivariate analyses (Generalized Linear Model with a binary logistic dependent variable) showed that one of the prominent variables affecting the occurrence of sleep bruxism was anxiety (mild, moderate and severe anxiety, Odds Ratios (OR) of 1.38, 2.08, and 2.35, respectively). Other variables associated with sleep bruxism were stress (each point in the stress scale increased the risk of SB by 3.2%), temporomandibular symptoms (OR = 2.17) and chewing difficulties (OR = 2.35). Neck pain showed a negative association (OR = 0.086). Multivariate analyses for awake bruxism showed an effect of moderate anxiety (OR = 1.6). Other variables associated with awake bruxism were stress (each point in stress scale increased the risk of AB by 3.3%), high and low levels of facial pain (OR = 2.94 and 1.53, respectively), creaks (OR = 1.85) and oral habits (OR = 1.36). Sleep bruxism was found to be a predictor for awake bruxism, and vice versa. In both cases ORs were 8.14.

Conclusions: Among adolescents, sleep and awake bruxism are associated with emotional aspects as well as with facial pain symptoms and/or masticatory system disturbances. Awareness is recommended to decrease potential risks to teeth, dental restorations, and the masticatory system.

Bruxism Unconscious Oral Habit in Everyday Life

BACKGROUND:

Bruxism is defined as an unconscious oral habit of rhythmical, unfunctional clenching, grinding and making chewy sounds with the teeth while making movements that are not part of the masticatory function and that lead to occlusal trauma.

AIM:

The purpose of this article is to show the habit bruxism, in everyday life, reviewing literature data.

METHODS:

Data was researched by using information on the internet on Researchgate, Pubmed, ScienceDirect, by analysing written articles and books and student books. From 200 articles that were analysed, 45 articles and two textbooks were involved in writing of this review article.

RESULTS:

Results derived from the analyzed literature, classify the main consequences of bruxism, from fatigue, pain, wasting of the incisal edges and occlusal surfaces of the teeth to loss of teeth, dental implants, headaches, periodontal lesions and TMD (dysfunctions of the masticatory muscles and temporomandibular joint (TMJ)) in severe cases. All these problems negatively affect the quality of everyday life of the patient.

CONCLUSION:

Bruxism as a parafunctional habit is present in everyday life needing a multidisciplinary approach for prevention of the teeth, bone and prosthetic restorations. The prevalence of bruxism is growing related to stress, drugs, changes in lifestyle, bad nutrition and sleep problems. The therapist should follow signs and symptoms to ensure the best treatment plan of the patient.

Bruxismo do sono: estudo de base populacional em pessoas com 18 anos ou mais na cidade de Rio Grande, Rio Grande do Sul

RESUMO: Objetivos: Avaliar a prevalência do bruxismo do sono, bem como seus principais sinais e sintomas, na cidade de Rio Grande, Rio Grande do Sul. Avaliar a associação do bruxismo do sono com sexo, idade, escolaridade e estresse psicológico. Método: O estudo foi do tipo transversal. Uma amostra representativa da população (1.280 pessoas residentes na zona urbana da cidade com idade maior ou igual a 18 anos de idade) foi entrevistada. A avaliação do bruxismo do sono foi realizada por meio de questionário baseado nos critérios diagnósticos da Classificação Internacional de Distúrbios do Sono. Resultados: A prevalência de bruxismo do sono encontrada na população foi de 8,1% (intervalo de confiança de 95% - IC95% - 6,6 - 9,5). Entre os sinais e sintomas da disfunção utilizados para o diagnóstico de bruxismo do sono, o desgaste dentário (70,3%) e a dor nos músculos mastigatórios (44,5%) foram os mais frequentemente relatados pelas pessoas que declararam ranger os dentes durante o sono. Não houve diferença significativa na prevalência de bruxismo do sono entre os sexos. A faixa etária com mais de 40 anos teve maior prevalência de bruxismo do sono. A disfunção foi associada a um maior nível de escolaridade (razão de prevalência - RP = 1,92; IC95% 1,35 - 2,72) e de estresse psicológico (RP = 1,76; IC95% 1,11 - 2,81). Conclusão: O bruxismo do sono tem uma importante prevalência na população em geral, causando diversos danos ao sistema estomatognático. O estresse psicológico é um fator de risco para essa disfunção.

Study of Associated Factors With Probable Sleep Bruxism Among Adolescents

STUDY OBJECTIVES

To evaluate the prevalence of probable sleep bruxism (SB) and its association with sleep features, orthodontic fixed appliance wearing, and extraoral and intraoral clinical signs and symptoms in a population of adolescents.

METHODS

Two hundred thirty-nine 12-year-old adolescents enrolled in private and public schools in Brumadinho, southeast Brazil, and their parents were invited to participate. They answered a questionnaire containing information regarding adolescents' sleep features and history of SB. Extraoral and intraoral examination was performed to identify some clinical signs (ie, absence of lip competence, presence of mouth breathing, clicks in the temporomandibular joint [TMJ], tooth wear) and symptoms (ie, pain in the masseter muscle upon palpation), and ongoing orthodontic treatment with fixed appliances. Parental report and clinical examination were used to determine probable SB. Descriptive statistics and logistic regression were performed to identify association of probable SB with independent variables.

RESULTS

Of 239 adolescents initially selected, 231 (96.6%) participated in the study. Prevalence of probable SB was 16.9%. Adolescents who snored during sleep (odds ratio [OR] = 3.14; 95% confidence interval [CI] = 1.47-6.70), adolescents who did not have clicks in the TMJ (OR = 3.37; 95% CI = 1.11-10.15), and those who wore orthodontic appliances (OR = 2.72; 95% CI = 1.04-7.14) were more likely to be in the group with probable SB.

CONCLUSIONS

Snoring, absence of clicks in the TMJ, and fixed appliance wearing were associated with probable SB among adolescents. This study adds to the ongoing research on SB in adolescents and its associated factors.

COMMENTARY

A commentary on this article appears in this issue on page 1281.

Association between Self-Reported Bruxism and Sleeping Patterns among Dental Students in Saudi Arabia: A Cross-Sectional Study

Objectives. The aim of this cross-sectional study was to identify sleeping patterns among dental students and their association with self-reported bruxism in Riyadh Colleges of Dentistry and Pharmacy (RCsDP). Methods. A cross-sectional study was performed including 549 students (67 men and 482 women). A structured questionnaire was adopted from The PSQI (The Pittsburgh Sleep Questionnaire Index) used for data collection. It included questions which are categorized into sleeping habits, sleep-related symptoms, and additional questions concerning bruxism. This questionnaire was randomly distributed among all college preclinical and postclinical students. Sleep bruxism diagnosis was based on self-reported data. The data were analyzed using Chi-square tests through SPSS software for Windows. Results. Statistical analyses revealed significant correlations between self-reported bruxism and sleeping habits including sleep initiation (χ² = 22.6, p = 0.000), continuous sleep until morning (χ² = 19.2, p = 0.001), nighttime sleep duration (χ² = 20.2, p = 0.000), and length of daytime naps (χ² = 28.35, p = 0.000). There was an association between self-reported bruxism and sleeping-related symptoms including awakening early in the morning before the usual time without a cause (χ² = 16.52, p = 0.000) and increased nightmares (χ² = 13.7, p = 0.001). Conclusions. Poor sleeping pattern was an important factor among dental students, who reported sleep bruxism.

Dental Implants Fatigue as a Possible Failure of Implantologic Treatment: The Importance of Randomness in Fatigue Behaviour

Objective. To show how random variables concern fatigue behaviour by a probabilistic finite element method. Methods. Uncertainties on material properties due to the existence of defects that cause material elastic constant are not the same in the whole dental implant the dimensions of the structural element and load history have a decisive influence on the fatigue process and therefore on the life of a dental implant. In order to measure these uncertainties, we used a method based on Markoff chains, Bogdanoff and Kozin cumulative damage model, and probabilistic finite elements method. Results. The results have been obtained by conventional and probabilistic methods. Mathematical models obtained the same result regarding fatigue life; however, the probabilistic model obtained a greater mean life but with more information because of the cumulative probability function. Conclusions. The present paper introduces an improved procedure to study fatigue behaviour in order to know statistics of the fatigue life (mean and variance) and its probability of failure (fatigue life versus probability of failure).

Association Between Self-Reported Bruxism and Malocclusion in University Students: A Cross-Sectional Study

OBJECTIVES

Bruxism can result in temporomandibular disorders, oral pain, and tooth wear. However, it is unclear whether bruxism affects malocclusion. The aim of this study was to examine the association between self-reported bruxism and malocclusion in university students.

METHODS

Students (n = 1503; 896 men and 607 women) aged 18 and 19 years were examined. Malocclusion was defined using a modified version of the Index of Orthodontic Treatment Need. The presence of buccal mucosa ridging, tooth wear, dental impression on the tongue, palatal/mandibular torus, and the number of teeth present were recorded, as well as body mass index (BMI). Additional information regarding gender, awareness of bruxism, orthodontic treatment, and oral habits was collected via questionnaire.

RESULTS

The proportion of students with malocclusion was 32% (n = 481). The awareness of clenching in males with malocclusion was significantly higher than in those with normal occlusion (chi square test, P < 0.01). According to logistic regression analysis, the probability of malocclusion was significantly associated with awareness of clenching (odds ratio [OR] 2.19; 95% confidence interval [CI], 1.22-3.93) and underweight (BMI <18.5 kg/m(2)) (OR 1.89; 95% CI, 1.31-2.71) in males but not in females. In subgroup analyses, the probability of crowding was also significantly associated with awareness of clenching and underweight (P < 0.01) in males.

CONCLUSIONS

Awareness of clenching and underweight were related to malocclusion (crowding) in university male students.

To see bruxism: a functional MRI study

OBJECTIVE

Since the pathophysiology of bruxism is not clearly understood, there exists no possible treatment. The aim of this study is to investigate the cerebral activation differences between healthy subjects and patients with bruxism on behalf of possible aetiological factors.

METHODS

12 healthy subjects and 12 patients with bruxism, a total of 24 right-handed female subjects (aged 20-27 years) were examined using functional MRI during tooth-clenching and resting tasks. Imaging was performed with 3.0-T MRI scanner with a 32-channel head coil. Differences in regional brain activity between patients with bruxism and healthy subjects (control group) were observed with BrainVoyager QX 2.8 (Brain Innovation, Maastricht, Netherlands) statistical data analysis program. Activation maps were created using the general linear model: single study and multistudy multisubject for statistical group analysis. This protocol was approved by the ethics committee of medical faculty of Kirikkale University, Turkey (02/04), based on the guidelines set forth in the Declaration of Helsinki.

RESULTS

The group analysis revealed a statistically significant increase in blood oxygenation level-dependent signal of three clusters in the control group (p<0.005), which may indicate brain regions related with somatognosis, repetitive passive motion, proprioception and tactile perception. These areas coincide with Brodmann areas 7, 31, 39 and 40. It is conceivable that there are differences between healthy subjects and patients with bruxism.

CONCLUSIONS

Our findings indicate that there was a decrease of cortical activation pattern in patients with bruxism in clenching tasks. This indicates decreased blood flow and activation in regional neuronal activity. Bruxism, as an oral motor disorder concerns dentistry, neurology and psychiatry. These results might improve the understanding and physiological handling of sleep bruxism.

Sleep Bruxism, Awake Bruxism and Sleep Quality among Brazilian Dental Students: A Cross-Sectional Study

The aim of the study was to evaluate the association of sleep bruxism, awake bruxism and sleep quality among dental students of the Federal University of Minas Gerais, Belo Horizonte, Brazil. A cross-sectional study was performed including 183 Brazilian dental students aged from 17 to 46 years old. The complete course curriculum consists of 9 semesters. Students enrolled in the first semester, the middle semester and the final semester of the course participated in the survey. The PSQI-BR (the Brazilian version of the Pittsburgh Sleep Questionnaire Index) was used for data collection. The PSQI-BR was distributed during lecture classes. Sleep bruxism and awake bruxism diagnosis was based on self-reported data. Descriptive analysis, Kruskal-Wallis, Mann-Whitney and Poisson regression with robust estimator were the statistical tests used. Sleep bruxism prevalence was 21.5% and awake bruxism prevalence was 36.5%. Sleep duration components were associated with sleep bruxism (PR=1.540; 95% CI: 1.00-2.37) and awake bruxism (PR=1.344; 95% CI: 1,008-1,790). There was an association between awake bruxism and habitual sleep efficiency component (PR=1.323; 95% CI: 1.03-1.70). Sleep disturbance component and awake bruxism were associated (PR=1.533; 95% CI: 1.03-2.27). Poor sleep quality was an important factor among dental students, who reported sleep bruxism as well as among those who presented awake bruxism

The psychology of tooth wear

AIM

To review the main psychological and mental conditions that are manifested dentally in the form of tooth wear. These conditions include depression, eating disorders, and alcohol and drug use disorders. The paper will also review the comorbidity of these conditions and the relevance of other medical conditions and lifestyle factors, such as gastroesophageal reflux disorder, smoking and diet, in the expression of tooth wear.

CONCLUSION

A holistic, multidisciplinary, healthcare approach is required in management of tooth wear patients with underlying mental health disorders. Dentists and Dental Care Professionals can have an important role in identifying these mental disorders through the observed tooth wear. They can also play a key role in monitoring patients' response and compliance to medical treatment through the monitoring of tooth wear progression and expression.

Sleep bruxism: a comprehensive overview for the dental clinician interested in sleep medicine

Sleep bruxism (SB) is a common sleep-related motor disorder characterized by tooth grinding and clenching. SB diagnosis is made on history of tooth grinding and confirmed by polysomnographic recording of electromyographic (EMG) episodes in the masseter and temporalis muscles. The typical EMG activity pattern in patients with SB is known as rhythmic masticatory muscle activity (RMMA). The authors observed that most RMMA episodes occur in association with sleep arousal and are preceded by physiologic activation of the central nervous and sympathetic cardiac systems. This article provides a comprehensive review of the cause, pathophysiology, assessment, and management of SB.

Changes in sleep as a function of adolescent development

Adolescence is marked by dramatic changes in sleep. Older adolescents go to bed later, have an increased preference for evening activities, and sleep less than younger adolescents. This behavior change is driven by external factors, notably increased pressures from academic, social, and extracurricular activities and by biological circadian factors. There are also substantial changes in sleep architecture across adolescence, with dramatic declines in slow wave sleep, and slow wave activity (delta, ~ 0.5-4.5 Hz). These changes are associated with underlying changes in brain structure and organization, with a decrease in synaptic density likely underlying the reduction in high amplitude slow waveforms. While changes in sleep across adolescence are a normal part of development, many adolescents are getting insufficient sleep and are consequently, less likely to perform well at school, more likely to develop mood-related disturbances, be obese, and are at greater risk for traffic accidents, alcohol and drug abuse.