Association between bruxism and temporomandibular disorders in children: A systematic review and meta-analysis

Bruxism, temporomandibular disorders, and headache-a narrative review of correlations and causalities

ABSTRACT

The co-occurrence of bruxism, temporomandibular disorders (TMDs), and headache is common in patients. However, there is conflicting evidence regarding whether this association is simply a result of their high prevalence or whether there are indeed causal relationships. This review provides an overview of the current state of research while taking into account the controversies surrounding research methods, particularly in definitions and diagnostic standards. Bruxism-defined as repetitive jaw muscle activity during sleep or wakefulness-is not a painful disorder but may-particularly in co-occurrence with TMD-worsen pre-existing headache. It seems important to differentiate between sleep and awake bruxism because of different impact on pathophysiological processes in different primary headache disorders such as migraine and tension-type headache. Temporomandibular disorder is a heterogenous entity with both myofascial and arthrogenous types of pain in addition to nonpainful disorders. Research suggests a correlation between TMD pain and migraine, as well as between awake bruxism and tension-type headache. However, psychosocial factors may act as confounders in these relationships. Determining causality is challenging because of the limited number of experimental and clinical studies conducted on this topic. The main finding is an apparent lack of consensus on the definition and assessment criteria for bruxism. Treatment wise, it is important to differentiate all 3 conditions because treatment of one condition may have an effect on the other 2 without proving causality. For future research, it is crucial to establish greater consistency and applicability in diagnostic procedures and definitions. In addition, more experimental and clinical studies investigating the question of causality are needed.

Evaluation of signs and symptoms of temporomandibular disorders and incisal relationships among 7-10-year-old Turkish children with sleep bruxism: A cross-sectional study

OBJECTIVE

To study the signs and symptoms of temporomandibular disorders (TMDs) and incisal relationships related to sleep bruxism and parafunctional habits among children.

METHODS

The study consisted of 106 children (53 with and 53 without bruxism) between the ages of 7 and 10. A general questionnaire and Diagnostic Criteria for Temporomandibular Disorders Axis I examination form were used for each child.

RESULTS

There were significant differences between children according to pain, headache, midline deviation, opening pattern, temporomandibular joint noise, overjet, overbite, corrected deviation, and pain disorders (p < 0.05). According to the logistic regression, the higher scores of "mouth breathing" and "horizontal incisal overjet" were independent risk factors for TMDs. The lack of "bruxism" and "sleeping with open mouth" were protective factors for TMDs.

CONCLUSION

Children with bruxism showed signs and symptoms of TMDs and divergence in incisal relationships.

Influence of malocclusion on sleep bruxism and orofacial pain: data from a study in school children

OBJECTIVES

This cross-sectional school-based study explored the influence of malocclusion on temporomandibular disorders (TMD) pain complaints, and whether this association would be mediated by sleep bruxism in a representative sample of 7- to 8-year-old children.

METHODS

Path analysis estimated direct, indirect, and total effects of occlusal features on sleep bruxism and TMD pain in 7- to 8-year-old children. Occlusal features were assessed with Dental Aesthetic Index (DAI), orofacial pain complaints using the TMD pain screener, possible sleep bruxism based on self-reports, and probable sleep bruxism based on self-reports combined with clinical findings. Structural equation modeling analyzed data with confounding factors.

RESULTS

From 580 participants, possible sleep bruxism was observed in 136 children (31.5%), probable sleep bruxism in 30 children (6.7%), and TMD pain complaints in 78 children (13.8%). Malocclusion had no direct effect on either possible sleep bruxism [standardized coefficient (SC) 0.000; p = 0.992], or TMD pain complaints (SC - 0.01; p = 0.740). When probable sleep bruxism was set as the mediator of interest, malocclusion did not directly affect probable sleep bruxism (SC 0.01; p = 0.766), nor TMD pain complaints (SC - 0.02; p = 0.515). A direct effect of probable sleep bruxism on TMD pain complaints was observed with an SC of 0.60 (p < 0.001). However, in neither case, malocclusion indirectly affected TMD pain complaints via bruxism.

CONCLUSION

Malocclusion in 7- to 8-year-old children did not directly influence possible or probable sleep bruxism or TMD pain complaints. Instead, probable sleep bruxism was strongly associated with TMD pain complaints.

CLINICAL SIGNIFICANCE

The impact of occlusal features on TMD pain complaints and bruxism has been a long-standing controversy in dentistry. However, the scientific literature linking this association may be inconsistent, mainly due to biased sample selection methods with inadequate consideration of confounders. Further research should try to identify additional risk factors for TMD pain in addition to probable sleep bruxism in children.

Factors associated with preschool children's sleep bruxism

OBJECTIVE

To evaluate the prevalence of sleep bruxism, related factors, and quality of life of preschool children and their families.

METHOD

The sample was 475 children between 4 and 5 years old enrolled in schools in the city of Bauru-Brazil. Parents/legal guardians answered two questionnaires, one to assess the presence of bruxism and related factors and another that was the validated Brazilian version of the Early Childhood Oral Health Impact Scale (B-ECOHIS). Intraoral clinical examination was performed by two trained examiners (Kappa = 0.82) within the school environment. The data were analyzed using statistics and the Mann-Whitney, Kruskal-Wallis, and Spearman correlation coefficient. The significance level was p < 0.05.

RESULTS

The prevalence of sleep bruxism was 47.4%. The highest prevalence was related to Class I canines and marked overjet, oral habits, such as nail biting, lip biting, chewing gum, and mouth breathing. Children with agitated sleep, reports of headache, and those considered aggressive, anxious, and/or shy were also more related.Conclusion: In the studied sample, sleep bruxism prevalence was high and related to important oral and general factors. Data also indicated SB as the main factor that interfered in the OHRQoL of children and their families.

Prevalence of Possible Sleep Bruxism and Its Association with Social and Orofacial Factors in Preschool Population

The prevalence of bruxism in the preschool population varies according to different investigations. The aim of this study was to investigate the prevalence of sleep bruxism and its relationship with social and orofacial factors in children aged 3 to 5 years. Three hundred forty-three preschool children were divided into two groups, one with nocturnal bruxism, as reported by parents, and another without this disorder. Questionnaires were distributed to the parents to determine the children's family social status and parafunctional habits at the time of the study. The clinical inspection confirmed the presence of certain parafunctional habits and the children's occlusal characteristics. The data obtained were analysed using descriptive statistics such as frequency chi-square tests to identify the influence of qualitative variables. Of the total sample, 28.9% of preschoolers presented sleep bruxism. The highest prevalence was observed in boys (61.6%) at the age of 5 years (41.4%). Characteristics associated with this pathology were lip incompetence, open bite, crossbite, and overbite, with p < 0.05. Sleep bruxism in preschool children has a higher prevalence in boys and is more frequently expressed from 5 years of age. Open bite, overbite, and crossbite should be considered factors associated with parafunction.

Diagnostic criteria for temporomandibular disorders-INfORM recommendations: Comprehensive and short-form adaptations for children

BACKGROUND

The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) are used worldwide in adults. Until now, no adaptation for use in children has been proposed.

OBJECTIVE

The aim of this study was to present comprehensive and short-form adaptations of Axis I and Axis II of the DC/TMD for adults that are appropriate for use with children in clinical and research settings.

METHODS

Global Delphi studies with experts in TMDs and in pain psychology identified ways of adapting the DC/TMD for children.

RESULTS

The proposed adaptation is suitable for children aged 6-9 years. Proposed changes in Axis I include (i) adapting the language of the Demographics and the Symptom Questionnaires to be developmentally appropriate for children, (ii) adding a general health questionnaire for children and one for their parents, (iii) replacing the TMD Pain Screener with the 3Q/TMD questionnaire and (iv) modifying the clinical examination protocol. Proposed changes in Axis II include (i) for the Graded Chronic Pain Scale, to be developmentally appropriate for children, (ii) adding anxiety and depression assessments that have been validated in children and (iii) adding three constructs (stress, catastrophising and sleep disorders) to assess psychosocial functioning in children.

CONCLUSION

The recommended DC/TMD, including Axis I and Axis II, for children aged 6-9 years, is appropriate for use in clinical and research settings. This adapted the first version for children includes changes in Axis I and Axis II changes requiring reliability and validity testing in international settings. Official translations to different languages according to INfORM requirements will enable a worldwide dissemination and implementation.

The effect of sleep hygiene and physiotherapy on bruxism, sleep, and oral habits in children with sleep bruxism during the COVID-19 pandemic

BACKGROUND

Sleep bruxism has been associated with temporomandibular dysfunction, pain, fatigue, and poor sleep quality.

OBJECTIVE

The aim of this study was to determine the gender and age distribution of sleep and oral habits of children with sleep bruxism and to examine the effect of a sleep hygiene and physiotherapy program.

METHODS

In this cross-sectional study, 82 children aged 6-13 years with sleep bruxism were initially screened between March 2020 and June 2021, from which 37 of them voluntarily attended an 8-week sleep hygiene and physiotherapy program. Evaluations were made using a Visual Analogue Scale (VAS), the Children's Sleep Habits Questionnaire (CSHQ), and the Oral Habits Questionnaire (OHQ) at the beginning and at the end of the 8-week program.

RESULTS

Statistically significant differences were determined between the 6-9 years and 10-13-year age groups in respect of the sleep habits subcategories of resistance to bedtime (p= 0.001), sleep anxiety (p= 0.043), parasomnia (p= 0.040), and sleep respiratory disorder (p= 0.041). Following the 8-week treatment program, a significant reduction was obtained in the VAS value (p< 0.05), CSHQ subcategories of resistance to bedtime (p= 0.001), sleep duration (p= 0.008), parasomnia (p= 0.000), and in the OHQ score (p= 0.000).

CONCLUSION

There was no relationship between sleep bruxism and gender, but a relationship was found with age. The rate of bruxism was seen to decrease with an increase in age. It was determined that oral, sleep habits, and bruxism are closely related, and the rates at which bruxism is seen are affected by the oral habits. Sleep hygiene and physiotherapy have been effective in children with sleep bruxism.

ACTN3 genotype influences masseter muscle characteristics and self-reported bruxism

OBJECTIVES

Main aim of the study was to explore the association between genetic polymorphisms in ACTN3 and bruxism. Secondary objectives included masseter muscle phenotypes assessment between bruxers and non-bruxers and according to genetic polymorphisms in ACTN3.

MATERIALS AND METHODS

Fifty-four patients undergoing orthognathic surgery for correction of their malocclusion were enrolled. Self-reported bruxism and temporomandibular disorders status were preoperatively recorded. Saliva samples were used for ACTN3 genotyping. Masseter muscle samples were collected bilaterally at the time of orthognathic surgery to explore the muscle fiber characteristics.

RESULTS

There were significant differences in genotypes for rs1815739 (R577X nonsense) (p = 0.001), rs1671064 (Q523R missense) (p = 0.005), and rs678397 (intronic variant) (p = 0.001) between bruxers and non-bruxers. Patients with self-reported bruxism presented a larger mean fiber area for types IIA (p = 0.035). The mean fiber areas in individuals with the wild-type CC genotype for rs1815739 (R577X) were significantly larger for type IIA fibers (1394.33 μm² [572.77 μm² ]) than in those with the TC and TT genotypes (832.61 μm² [602.43 μm² ] and 526.58 μm² [432.21 μm² ] [p = 0.014]). Similar results for Q523R missense and intronic variants.

CONCLUSIONS

ACTN3 genotypes influence self-reported bruxism in patients with dentofacial deformity through specific masseter muscle fiber characteristics.

Relationship Analogy between Sleep Bruxism and Temporomandibular Disorders in Children: A Narrative Review

Sleep bruxism (SB) is a condition characterized by repetitive clenching or grinding teeth and/or by bracing or thrusting of the mandible during sleep. Although SB is not considered a disorder in children, SB can be a potential physical and psychological hazard or consequence, and this study examines whether SB is a risk factor for TMD as it is in adults. A narrative review on the topic of inferring the relationship between sleep bruxism and TMD in children was performed based on a search in the PubMed and Google Scholar databases for articles published between 1999 and 2022. A total of 76 articles were included in this review. SB is very common in children, may be related to psychological distress or sleep breathing disorder, with a prevalence of up to 49%, and mainly occurs in the non-rapid eye movement stage in the sleep structure. SB may be one cause of TMD. The prevalence of TMD in children is 16–33%. Compared to the female-dominant TMD prevalence in adults, the sex-differences in TMD prevalence in children are less pronounced. However, TMD-related pain is more prevalent in girls than in boys. Given the complex etiology of each of SB and TMD in children, it can be inferred that the explanation of the relationship between the two conditions is very challenging. Ultimately, their relationship should be understood in the individual biopsychosocial model in the process of special physical growth and mental development of children. Moreover, appropriate clinical guidelines for a definitive diagnosis of SB and TMD in children and more research with a high scientific evidence level, which is comprehensive, considering physical, psychological, genetic, and social cultural factors, are required.

The impact of mouth breathing on dentofacial development: A concise review

Mouth breathing is one of the most common deleterious oral habits in children. It often results from upper airway obstruction, making the air enter completely or partially through oral cavity. In addition to nasal obstruction caused by various kinds of nasal diseases, the pathological hypertrophy of adenoids and/or tonsils is often the main etiologic factor of mouth breathing in children. Uncorrected mouth breathing can result in abnormal dental and maxillofacial development and affect the health of dentofacial system. Mouth breathers may present various types of growth patterns and malocclusion, depending on the exact etiology of mouth breathing. Furthermore, breathing through the oral cavity can negatively affect oral health, increasing the risk of caries and periodontal diseases. This review aims to provide a summary of recent publications with regard to the impact of mouth breathing on dentofacial development, describe their consistencies and differences, and briefly discuss potential reasons behind inconsistent findings.

Temporomandibular disorder in construction workers associated with ANKK1 and DRD2 genes

The study aimed to explore the influence of genetic polymorphisms in ANKK1 and DRD2 on the signs and symptoms of temporomandibular disorder (TMD) in construction workers. This cross-sectional study included only male subjects. All construction workers were healthy and over 18 years age. Illiterate workers and functionally illiterate workers were excluded. The diagnosis of TMD was established according to the Research Diagnostic Criteria for TMD (RDC/TMD). Genomic DNA was used to evaluate the genetic polymorphisms ANKK1 (rs1800497) and DRD2 (rs6275; rs6276) using Real-Time PCR. Chi-square or Fisher exact tests were used to evaluate genotypes and allele distribution among the studied phenotypes. The established alpha of this study was 5%. The sample included a total of 115 patients. The age of the patients ranged from 19 to 70 years (mean age 38.2; standard deviation 11.7). Chronic pain (87.7%), disc displacement (38.2%), and joint inflammation (26.9%) were the most frequently observed signs and symptoms. The genetic polymorphism rs6276 in DRD2 was associated with chronic pain (p=0.033). In conclusion, our study suggests that genetic polymorphisms in DRD2 and ANKK1 may influence TMD signs and symptoms in a group of male construction workers.

Accuracy of Surface Electromyography in the Diagnosis of Pain-Related Temporomandibular Disorders in Children with Awake Bruxism

The study assessed masticatory muscle electromyographic (EMG) activity in both children diagnosed with pain-related temporomandibular disorders (TMD-P) and awake bruxism (AB) and in children without TMD, as well as the diagnostic value of surface electromyography (sEMG) in diagnosing TMD-P in subjects with AB. After evaluation based on the Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), 30 children diagnosed with myofascial pain were included in the myofascial pain group and 30 children without TMD diagnosis comprised the control group (mean age of 9.49 ± 1.34 years). The activity of the anterior temporal (TA) and masseter (MM) muscle was assessed bilaterally using a DAB-Bluetooth device (zebris Medical GmBH, Germany) at rest and during maximum voluntary clenching (MVC). The receiver operating characteristic (ROC) curve was used to determine the accuracy, sensitivity, and specificity of the normalized sEMG data. Statistically significant intergroup differences were observed in TA and MM muscle EMG activity at rest and during MVC. Moderate degree of sEMG accuracy in discriminating between TMD-P and non-TMD children was observed for TA_mean, left MM, and MM_mean EMG muscle activity at rest. sEMG can be a useful tool in assessing myofascial TMD pain in patients with AB.

Diagnostic criteria for temporomandibular disorders (DC/TMD) in children and adolescents: an international Delphi study-Part 2-Development of Axis II

BACKGROUND

Unlike the psychosocial assessment established for adults in the diagnostic criteria for temporomandibular disorders (DC/TMD), a standardized psychosocial assessment for children and adolescents with TMD complaints has not yet been established.

OBJECTIVES

To develop a new standardized instrument set to assess the psychosocial functioning in children and adolescents by adapting the psychosocial status and pain-related disability (Axis II) of the adult DC/TMD and by including new instruments.

METHODS

A modified Delphi method was used to survey 23 international TMD experts and four international experts in pain-related psychological factors for consensus regarding assessment tools for psychosocial functioning and pain-related disability in children and adolescents. The TMD experts reviewed 29 Axis II statements at round 1, 13 at round 2, and 2 at round 3. Agreement was set at 80% for first-round consensus level and 70% for each of the second and third rounds. The psychological experts completed a complementary Delphi survey to reach a consensus on tools to use to assess more complex psychological domains in children and adolescents. For the psychological experts, the first round included 10 open-ended questions on preferred screening tools for depression, anxiety, catastrophizing, sleep problems, and stress in children (ages 6-9 years old) and adolescents (ages 10-19 years old) as well as on other domains suggested for investigation. In the second round, the psychological experts received a 9-item questionnaire to prioritize the suggested instruments from most to least recommended.

RESULTS

The TMD experts, after three Delphi rounds, reached consensus on the changes of DC/TMD to create a form to evaluate Axis II in children and adolescents with TMD complaints. The psychological experts added tools to assess depression and anxiety, sleep disorders, catastrophizing, stress, and resilience.

CONCLUSION

Through international expert consensus, this study adapted Axis II of the adult DC/TMD to assess psychosocial functioning and pain-related disability in children and adolescents. The adapted Axis II protocols will be validated in the target populations.

Evaluation of the Oxidative Stress Level and Serum Prolidase Activity in Patients with Sleep Bruxism

Aims and Objective:

Sleep bruxism is a complicated disease, and its cause remains controversial. If the etiology of bruxism is resolved, the treatment can be adjusted to the prevailing aetiological factor. Thus, the aim of this study was to evaluate the oxidative stress level and serum prolidase activity in patients with sleep bruxism.

Materials and Methods:

Seventy healthy subjects and 51 patients with sleep bruxism were included in this study, and blood samples from all patients were collected. Serum samples were analyzed for total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and prolidase activity.

Results:

The prolidase, TOS, and OSI levels were significantly higher in patients with bruxism than in the healthy controls (p = 0.001, p = 0.001, p = 0.001, respectively). The TAS level was significantly lower in bruxism patients than in healthy controls (p = 0.003).

Conclusion:

The increased TOS, OSI, and prolidase levels and decreased TAS levels could be assumed to result in oxidative injury in patients with sleep bruxism. However, the study could not determine whether oxidative imbalance and increased serum prolidase levels could be a cause or a result of bruxism.