Correlation between Bruxism and Gastroesophageal Reflux Disorder and Their Effects on Tooth Wear. A Systematic Review

Genetic polymorphisms and bruxism: A scoping review

BACKGROUND

Recent studies have highlighted the multifactorial nature of bruxism, with behavioral, psychosocial, and physiological factors, including genetic predisposition, contributing to its development. However, the role of genetic markers in determining susceptibility to bruxism remains poorly understood, with limited studies offering significant findings.

OBJECTIVES

To identify the current knowledge to investigate the susceptibility of genetic markers for sleep (SB) and/or awake bruxism (AB).

MATERIALS AND METHODS

Seven electronic databases and two grey literature platforms were searched up to January 2024. We included studies that related different types of genes and/or genetic polymorphisms with different types of bruxism, regardless of age or sex of the participants. To be included the study must have described the form of detection of bruxism.

RESULTS

A total of 21 reports were included. Of these, 16 were primary research reports. The remaining five articles consisted of four systematic reviews and a literature review incorporating a systematic mapping process, and network visualization. Within the pool of 16 primary study reports, seven focused on the association of genetic polymorphisms with both SB and AB, while seven concentrated solely on the association with SB. One primary study reported results related to probable AB and one article did not specify the bruxism type. Regarding all the studied genes and polymorphisms, significant association results were obtained for 15 polymorphisms from 11 different genes. Self-reported SB was associated with genes from the serotonergic (5HTR2A) and dopaminergic pathways (DRD2, DRD3, and ANKK1), as well as genes encoding enzymes (COMT and MMP9) and proteins (ACTN3 and ANKK1). Instrumentally reported SB was linked only to the reverse telomerase gene (TERT). Self-reported AB was associated with the ACTN3 and ANKK1 genes.

CONCLUSION

This review identified 30 genes and 56 polymorphisms variations potentially associated with either SB or AB. However, few presented significant results regarding positive associations, mostly acting at neurotransmitter pathways. The authors recommend further studies to determine the susceptibility of genetic markers as a risk factor for bruxism.

Sleep bruxism (SB) may be not associated with obstructive sleep apnea (OSA): A comprehensive assessment employing a systematic review and meta-analysis

Associations between obstructive sleep apnea (OSA) and sleep bruxism (SB) are the subject of discussion but have not been confirmed definitively. Therefore, the objective of this meta-analysis was to examine the relationship between OSA and SB. This systematic review was conducted in accordance with PRISMA 2020 guidelines. PubMed, Embase and Web of Science were screened up to February 2024. The risk of bias was assessed with the Joanna Briggs Institute tool. 2260 records were identified, but only 14 studies were included. The odds of SB presence in OSA did not differ from the control group (OR: 1.23, 95 % CI: 0.47-3.20). The chance of SB compared to controls also did not differ in mild OSA (OR: 1.56, 95 % CI: 0.76-3.18), in moderate OSA (OR: 1.51, 95 % CI: 0.77-2.94) and in severe OSA (OR: 1.50, 95 % CI: 0.68-3.29). Additionally, the odds of SB were not increased in moderate OSA in comparison to mild OSA (OR: 1.14, 95 % CI: 0.63-2.94), in severe OSA compared to moderate OSA (OR: 1.31, 95 % CI: 0.61-2.79) or in severe OSA compared to mild OSA (OR = 1.42, 95 % CI: 0.69-2.93). The presence of SB in OSA did not differ between genders (OR: 2.14, 95 % CI: 0.65-7.05). The quality of the major studies included is low; therefore, the noted lack of correlation between OSA and SB may require further research. The relationship between OSA and SB seems to be multi-faceted. Presented results should not exempt clinicians from exact diagnosis of concomitant sleep conditions in OSA subjects.

Exploring the Association Between Gastroesophageal Reflux and Temporomandibular Joint Disorder in European Populations: A Bidirectional Mendelian Randomization Analysis

INTRODUCTION AND AIMS

Gastroesophageal reflux disease (GERD) and temporomandibular joint disorder (TMD) are relatively common conditions with a potential causal relationship. This study aims to investigate the possible causal relationship between GERD and TMD through bidirectional Mendelian randomization analysis.

METHODS

Using data from large GWAS databases, we conducted bidirectional Mendelian randomization analyses to investigate the potential causal link between GERD and TMD. Instrumental variables were selected from the IEU platform, comprising 129,080 GERD cases and 473,524 controls from the UK Biobank. TMD data from the FinnGen project included 6,314 cases and 222,498 controls.

RESULTS

The forward MR analysis suggested that GERD may increase the risk of TMD (OR = 1.47, 95% CI: 1.20-1.81, P = 2e-4). The Weighted Median method also yielded significant results (OR = 1.53, 95% CI: 1.14-2.04, P = 4.1e-3). However, the reverse MR analysis did not reveal a significant association between TMD and GERD (OR = 1.02, 95% CI: 0.98-1.05, P = .33).

CONCLUSION

This study, employing MR analysis, provides initial evidence supporting a potential causal relationship between GERD and TMD. The findings contribute to a better understanding of the relationship between these two conditions and offer insights for future clinical investigations.

CLINICAL RELEVANCE

The findings of this study hold potential clinical significance in guiding early management strategies for GERD, reducing the incidence of TMD, and optimizing healthcare resource allocation, thereby improving patient quality of life. Further clinical studies are warranted to validate these findings and explore underlying mechanisms.

Awake bruxism behaviors frequency in a group of healthy young adults with different psychological scores

OBJECTIVE

To assess the frequency of awake bruxism (AB) behaviors in a group of undergraduate dentistry students and correlate it with the status of anxiety and depression.

MATERIALS AND METHODS

The frequency of five oral behaviors (i.e., relaxed jaw muscle, teeth contact, mandible bracing, teeth clenching, teeth grinding) was evaluated using a smartphone-based ecological momentary assessment (EMA) approach. The anxiety and depression status was investigated with the four-item patient health questionnaire for anxiety and depression (PHQ-4). ANOVA with Tukey post-hoc test was used to assess the difference in frequency of AB behaviors among the four PHQ-4 groups.

RESULTS

Among the four groups, there was a statistically significant difference in the frequency of relaxed jaw muscle, teeth contact, mandible bracing, and teeth clenching, but not for teeth grinding.

CONCLUSION

Based on this cross-sectional study's findings, psyche seems to have a determinant impact on AB behaviors, which is significantly higher in individuals with anxiety and depression traits.

Intraoral Scanning for Monitoring Dental Wear and Its Risk Factors: A Prospective Study

Dental wear arises from mechanical (attrition or abrasion) and chemical (erosion) factors. Despite its prevalence and clinical significance, accurately measuring and understanding its causes remain challenging in everyday practice. This one-year study with 39 participants involved comprehensive examinations and full-arch intraoral scans at the start and after 12 months. Volume loss exceeding 100 µ on each tooth's surfaces (buccal, lingual/palatine and incisal/occlusal) was measured by comparing three-dimensional scans from both time points. This study also assessed factors such as abrasion and erosion through clinical exams and questionnaires. There were no significant differences in dental wear in participants with sleep bruxism. However, noticeable wear occurred in the front teeth of those with waking bruxism and joint-related symptoms. Increased wear was associated with frequent consumption of acidic drinks, regular swimming, dry mouth, nocturnal drooling and heartburn, while no significant wear was found in patients with reflux. The used methodology proved effective in accurately assessing the progression of dental wear, which is important as many patients may initially be asymptomatic. The variability observed in dental wear patterns underscores the need to develop specific software applications that allow immediate and efficient comparison of wear areas based on extensive analysis of patient databases.

Investigation of Bruxism wear behavior of titanium alloy biomaterials; experimental and 3D finite element simulation

Bruxism can be defined as the process of direct contact with teeth and dental materials with an involuntary jaw-tightening movement. In this process, teeth and dental materials can be exposed to various damage mechanisms. This study aims to realize the mechanism of bruxism with finite element analysis and in vitro rotating chewing movement analysis. Within the scope of the study, cp-Ti, Ti-5Zr, and Ti-5Ta materials were subjected to wear tests in the finite element analysis and in vitro rotating chewing movement method under the determined Bruxism chewing test conditions. Test specimens with cylindrical geometry were exposed to a direct every-contact wear mechanism for 30 s under 150 N bruxism chewing bite force. The bruxism chewing cycle continued for 300 min at a frequency of 2 Hz. Microanalysis of the wear surfaces of the samples after the experimental study was carried out with Scanning Electron Microscopy. The results obtained within the scope of this study showed that the Bruxism wear resistance increased by adding zirconium and tantalum to pure titanium material. This result shows that pure titanium material, which is known to have poor wear resistance, can be improved with Zr and Ta alloys. It is clinically important that the success rate in the treatment process increases with the increase in wear resistance. However, the micro-cracks observed in the microstructure may have occurred in the sub-surface, which is a show of the fatigue wear mechanism.

Investigation of the presence of Non-carious cervical lesions (NCCLs) in ancient adult skulls: analyzing data from prehistoric and historical samples through a systematic review and meta-analysis

OBJECTIVES

Historically, the prevalence of caries has undergone significant changes, particularly increasing with the industrialization of sugar consumption. When examining ancient populations, lower caries rates are discovered, attributed in part to dietary factors. These populations consumed abrasive foods, leading to occlusal wear and reduced non-axial occlusal forces, potentially influencing Non-Carious Cervical Lesions (NCCLs). Although some attribute NCCLs to abfraction, the mechanism remains debated. This systematic review aims to evaluate the presence of NCCLs in ancient populations, shedding light on the factors contributing to their occurrence.

MATERIALS AND METHODS

The present systematic review was registered on PROSPERO, and the manuscript was prepared following PRISMA guidelines.

RESULTS

After the literature search and article screening, data from 6 studies were included in the meta-analysis, with only 2 reporting NCCLs in ancient skulls, encopassing 17 subjects in 805 examined skulls, suggesting their presence even before the widespread use of toothbrushes. This finding indicates a potential etiopathogenic mechanism linked to abfraction, but the cause is complex and involves abrasive and erosive factors closely tied to dietary habits.

CONCLUSIONS

In summary, NCCLs were present in ancient populations, albeit with a much lower prevalence. Their occurrence cannot be solely attributed to wear mechanisms but must be connected to abrasive factors related to diet or practices with religious and cultural significance, such as the use of labrets.

CLINICAL RELEVANCE

Th the knowledge of NCCLs presence in acient sculls is crucial today for better understand the associated risk factors. In this context, the analysis of ancient skulls allows us to discern the role that tooth brushing and diet played in the formation of NCCLs, over the past century.

Inflammatory Markers and Sleep Architecture in Sleep Bruxism-A Case-Control Study

Background: Sleep bruxism (SB) is a common sleep-related movement behavior with a multifaceted etiology and a deficiently understood pathophysiology. A recent hypothesis suggests a link between SB and systemic inflammation. The scope of the study was to determine whether bruxers have altered sleep structure and different levels of inflammatory parameters compared to nonbruxers. Methods: A total of 83 adults underwent full-night polysomnography. The polysomnograms were evaluated using the American Academy of Sleep Medicine (AASM) guidelines. Then, the blood samples were obtained from the participants by venipuncture and the analyses were performed. The study group was divided based on bruxism episode index (BEI) into two groups: BEI ≤ 4 and BEI > 4. Results: In comparison with nonbruxers, the oxygen desaturation index (ODI) was significantly higher in severe bruxers (7.5 ± 11.08 vs. 3.33 ± 5.75, p < 0.005), as well as the arousal parameters (7.77 ± 4.68 vs. 4.03 ± 2.97, p < 0.001), and the mean oxygen desaturation (3.49 ± 0.69 vs. 3.01 ± 0.67, p < 0.05). Moreover, the differences in sleep architecture and deprivation of the deep sleep phase were observed, the non-REM sleep stage 3 was significantly shorter in severe bruxers (p < 0.03). Differences were also noted in non-REM sleep stage 1 and REM sleep phase. In the investigated group, there were no statistical differences in inflammatory cytokines levels between bruxers and nonbruxers. Conclusions: Sleep bruxism is associated with sleep structure alterations and may be associated with deep sleep phase deprivation. The inflammatory markers are not linearly correlated with the severity of sleep bruxism expressed as BEI.

Sleep Bruxism in Children: A Narrative Review

Sleep bruxism, characterized by involuntary grinding or clenching of the teeth and/or by bracing or thrusting of the mandible during sleep, is common in children. Sleep bruxism occurs while the patient is asleep. As such, diagnosis can be difficult as the affected child is usually unaware of the tooth grinding sounds. This article aims to familiarize physicians with the diagnosis and management of sleep bruxism in children. A search was conducted in May 2023 in PubMed Clinical Queries using the key terms "Bruxism" OR "Teeth grinding" AND "sleep". The search strategy included all observational studies, clinical trials, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. According to the International classification of sleep disorders, the minimum criteria for the diagnosis of sleep bruxism are (1) the presence of frequent or regular (at least three nights per week for at least three months) tooth grinding sounds during sleep and (2) at least one or more of the following (a) abnormal tooth wear; (b) transient morning jaw muscle fatigue or pain; (c) temporary headache; or (d) jaw locking on awaking. According to the International Consensus on the assessment of bruxism, "possible" sleep bruxism can be diagnosed based on self-report or report from family members of tooth-grinding sounds during sleep; "probable" sleep bruxism based on self-report or report from family members of tooth-grinding sounds during sleep plus clinical findings suggestive of bruxism (e.g., abnormal tooth wear, hypertrophy and/or tenderness of masseter muscles, or tongue/lip indentation); and "definite" sleep bruxism based on the history and clinical findings and confirmation by polysomnography, preferably combined with video and audio recording. Although polysomnography is the gold standard for the diagnosis of sleep bruxism, because of the high cost, lengthy time involvement, and the need for high levels of technical competence, polysomnography is not available for use in most clinical settings. On the other hand, since sleep bruxism occurs while the patient is asleep, diagnosis can be difficult as the affected child is usually unaware of the tooth grinding sounds. In clinical practice, the diagnosis of sleep bruxism is often based on the history (e.g., reports of grinding noises during sleep) and clinical findings (e.g., tooth wear, hypertrophy and/or tenderness of masseter muscles). In childhood, sleep-bruxism is typically self-limited and does not require specific treatment. Causative or triggering factors should be eliminated if possible. The importance of sleep hygiene cannot be over-emphasized. Bedtime should be relaxed and enjoyable. Mental stimulation and physical activity should be limited before going to bed. For adults with frequent and severe sleep bruxism who do not respond to the above measures, oral devices can be considered to protect teeth from further damage during bruxism episodes. As the orofacial structures are still developing in the pediatric age group, the benefits and risks of using oral devices should be taken into consideration. Pharmacotherapy is not a favorable option and is rarely used in children. Current evidence on the effective interventions for the management of sleep bruxism in children is inconclusive. There is insufficient evidence to make recommendations for specific treatment at this time.

Secondary bruxism: A valid diagnosis or just a coincidental finding of additional masticatory muscle activity? A narrative review of literature

INTRODUCTION

Bruxism is defined as a repetitive masticatory muscle activity that can manifest it upon awakening (awake bruxism-AB) or during sleep (sleep bruxism-SB). Some forms of both, AB and SB can be associated to many other coexistent factors, considered of risk for the initiation and maintenance of the bruxism. Although controversial, the term 'secondary bruxism' has frequently been used to label these cases. The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques, however, are important factors to be considered when judging the literature findings. The use (and abuse) of drugs, caffeine, nicotine, alcohol and psychoactive substances, the presence of respiratory disorders during sleep, gastroesophageal reflux disorders and movement, neurological and psychiatric disorders are among these factors. The scarcity of controlled studies and the complexity and interactions among all aforementioned factors, unfortunately, does not allow to establish any causality or temporal association with SB and AB. The supposition that variables are related depends on different parameters, not clearly demonstrated in the available studies.

OBJECTIVES

This narrative review aims at providing oral health care professionals with an update on the co-risk factors and disorders possibly associated with bruxism. In addition, the authors discuss the appropriateness of the term 'secondary bruxism' as a valid diagnostic category based on the available evidence.

CONCLUSION

The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques found in many studies preclude any solid and convincing conclusion on the existence of the 'secondary' bruxism.

Risk factors of tooth wear in permanent dentition: A scoping review

BACKGROUND

Tooth wear (TW) prevalence is high and increasing and has important consequences on the patient's quality of life. Knowledge of risk factors is crucial to promote diagnosis, prevention strategies and timely interceptive treatment. Many studies have identified TW risk factors.

OBJECTIVE

This scoping review aims to map and describe suspected available factors associated with TW in permanent dentition based on quantitative measurement.

METHODS

The scoping review was conducted using the PRISMA extension of the Scoping Reviews checklist. The search was conducted in October 2022 from the Medline® (PubMed® interface) and Scopus® databases. Two independent reviewers selected and characterised the studies.

RESULTS

2702 articles were identified for assessment of titles and abstracts, and 273 articles were included in the review. The results show a need to standardise TW measurement indices and the study design. The included studies highlighted various factors, classified into nine domains: sociodemographic factors, medical history, drinking habits, eating habits, oral hygiene habits, dental factors, bruxism and temporomandibular disorders, behavioural factors, and stress. Results related to chemical TW (erosion) risk factors underline the importance of eating disorders, gastroesophageal reflux and lifestyle, particularly drinking and eating behaviours, which supports developing public health information campaigns and interventions. Besides chemical, this review identifies evidence of several mechanical TW risk factors, such as toothbrushing and bruxism; the influence of this last factor needs to be further explored.

CONCLUSIONS

TW management and prevention require a multidisciplinary approach. Dentists are in the first line to detect associated diseases such as reflux or eating disorders. Consequently, practitioners' information and guideline diffusion should be promoted, and a TW risk factors checklist (the ToWeR checklist) is proposed to help diagnostic approaches.

Effect of the Abutment Rigidity on the Wear Resistance of a Lithium Disilicate Glass Ceramic: An In Vitro Study

Lithium disilicate (LDS) glass ceramics are among the most common biomaterials in conservative dentistry and prosthodontics, and their wear behavior is of paramount clinical interest. An innovative in vitro model is presented, which employs CAD/CAM technology to simulate the periodontal ligament and alveolar bone. The model aims to evaluate the effect of the abutment rigidity on the wear resistance of the LDS glass ceramic. Two experimental groups (LDS restorations supported by dental implants, named LDS-on-Implant, or by hybrid ceramic tooth replicas with artificial periodontal ligament, named LDS-on-Tooth-Replica) and a control group (LDS-Cylinders) were compared. Fifteen samples (n = 15) were fabricated for each group and subjected to testing, with LDS antagonistic cusps opposing them over 120,000 cycles using a dual axis chewing simulator. Wear resistance was analyzed by measuring the vertical wear depth (mm) and the volume loss (mm3) on each LDS sample, as well as the linear antagonist wear (mm) on LDS cusps. Mean values were calculated for LDS-Cylinders (0.186 mm, 0.322 mm3, 0.220 mm, respectively), LDS-on-Implant (0.128 mm, 0.166 mm3, 0.199 mm, respectively), and LDS-on-Tooth-Replica (0.098 mm, 0.107 mm3, 0.172 mm, respectively) and compared using one-way-ANOVA and Tukey's tests. The level of significance was set at 0.05 in all tests. Wear facets were inspected under a scanning electron microscope. Data analysis revealed that abutment rigidity was able to significantly affect the wear pattern of LDS, which seems to be more intense on rigid implant-abutment supports compared to resilient teeth replicas with artificial periodontal ligament.

Deterioration of direct restorative materials under erosive conditions with impact of abrasion and attrition in vitro

Objective

To compare the cumulative impact of sequential wear on mechanical properties and appearance of a composite resin (CR), Filtek Z250^®, a glass ionomer GI, Fuji IX GP^®, and a glass hybrid (GH), Equia Forte^®.

Material and Methods

Six equally sized specimens of each material were subjected to wear tests, i.e., simulation of brushing, chewing and acidic liquid exposure, mimicking at least 6 months of clinical exposure. Surface roughness, hardness, substance loss and degree of shade lightness were determined.

Results

Following wear tests, significant increase in surface roughness and decrease in hardness values were observed for all materials (p < .05). Significantly larger substance loss was found in Equia Forte^® specimens compared to Filtek Z250^® (p < .05), while that of Fuji IX^® exceeded the measurement capacity of the instrument. Opposite to the two other materials, the shade of Filtek Z250^® became darker.

Conclusions

Sequential wear exposure mimicking abrasion, erosion and attrition to products representing CR, GI and GH, caused weakening and change in appearance of the materials. The composite resin was the most mechanically resistant to the sequential wear.

Relationships between tooth wear, bruxism and temporomandibular disorders

This article will provide an overview of the diagnosis of common temporomandibular disorders (TMDs) and bruxism, along with their relevance in management of tooth wear. When assessing and managing a tooth wear case, the teeth should not be considered in isolation, but as part of the articulatory system, which has three inter-related elements: the teeth, the temporomandibular joints and the masticatory muscles. The presence/absence of bruxism and TMD are highly relevant, although there may not be a causal relationship between these. A consideration of TMD and bruxism, together with the potential impact these may have on the patient during and after any management of tooth wear, will form part of patient education and the informed consent process.