The effect of intermittent use of occlusal splint devices on sleep bruxism: a 4-week observation with a portable electromyographic recording device

Attitude of Italian dental practitioners toward bruxism assessment and management: A survey-based study

INTRODUCTION

Bruxism is a spectrum of masticatory muscles activities. According to the recent evidence and international consensus, there is no indication to treat bruxism unless clinical consequences are present. The aim of the present study was to investigate the approach of Italian dentists to bruxism in their clinical practice.

METHODS

An anonymous online survey was developed, composed by 26 items grouped into five sections: (1) Characteristics of the respondent (Q1-Q6); (2) Bruxism frequencies (Q7-Q11); (3) Bruxism assessment (Q12-Q15); (4) Bruxism management (Q16-Q20); (5) Occlusal splints therapy (Q21-Q26).

RESULTS

A total of 384 practitioners, including specialists and non-specialists, participated in this survey. The majority of the respondents reported that 1-3 out of ten patients presented with bruxism. The diagnosis is mainly performed with non-instrumental methods, and facial pain and dental wear are the major clinical consequence associated with bruxism. Almost the entire sample of respondents report to offer occlusal splints to bruxism patients, and 41% refer to perform occlusal adjustments. Almost half of the respondents have never proposed any form of cognitive-behavioural therapy.

CONCLUSION

The results of the current survey highlighted several inconsistencies in Italian dentists' approaches to bruxism, suggesting the need for better education of practitioners and for the development of a standardized protocol to assess and manage bruxism in dental practices.

Short-Term Effects of 3D-Printed Occlusal Splints and Conventional Splints on Sleep Bruxism Activity: EMG-ECG Night Recordings of a Sample of Young Adults

(1) Background: This study aims to compare the effects of 3D-printed splints and conventional manufactured splints on sleep bruxism (SB) EMG activity. (2) Methods: Twenty-six patients (19 M, 7 F, 25.8 ± 2.6 years) were randomly allocated to a study group (3D splints) and a control group (conventional manufactured splints) and followed for a period of three months with night EMG-ECG recordings. Samples of the involved materials were analyzed for nanoindentation. The outcomes of interest considered were the overall SB index, the total amount of surface masseter muscle activity (sMMA), and general and SB-related phasic and tonic contractions. A statistical evaluation was performed with a confidence interval (CI) between 2.5% and 97.5%. (3) Results: Differences between groups with OAs were observed for general tonic contraction (p = 0.0009), while differences between recording times were observed for general phasic contractions (p = 0.002) and general tonic contractions (p = 0.00001). Differences between recording times were observed for the total amount of sMMA (p = 0.01), for general phasic contractions (p = 0.0001), and for general tonic contractions (p = 0.000009) during night recordings without OAs. (4) Conclusions: Three-dimensional splints seem to have a higher impact on SB-related electromyographic activity but not on the overall sleep bruxism index. The more regular surfaces offered by 3D splints could be related to phasic contraction stabilization.

Short-term effect of material type and thickness of occlusal splints on maximum bite force and sleep quality in patients with sleep bruxism: a randomized controlled clinical trial

OBJECTIVE

To evaluate the short-term effects of hard and soft splints of different thicknesses on maximum bite force (MBF) and sleep quality (SQ) in participants with sleep bruxism (SB).

METHODS

One-hundred-fifteen patients were randomly allocated to five groups: Groups H2(Hard splint-2 mm), H3(Hard splint-3 mm), S2(Soft splint-2 mm), S3(Soft splint-3 mm), and C (control). Outcomes were MBF (assessed with a digital gnathodynamometer) and SQ (assessed with the Pittsburgh Sleep Quality Index). Measurements were performed at T0 (before the splints), T1 (1-month follow-up), and T2 (2-months follow-up). Data were analyzed using one-way analysis of variance(ANOVA), Tukey's HSD, and chi-square tests (alpha = 0.05).

RESULTS

At T1, the highest MBF values were observed in group H3 (658.01 ± 22.6 N), while the lowest in group S2 (585.45 ± 8.68 N). For T2, the highest values were obtained in H3 group (676.85 ± 21.9 N), and the lowest in group S2 (565.65 ± 10.9 N) (p < 0.05).For SQ, groups S2 and S3 revealed the lowest PSQI values at T1 (9.1; 9.6) and T2 (9; 9.5) (p < 0.001).

CONCLUSIONS

The short-term use of both 2 and 3-mm thick soft splints resulted in a decrease in MBF. Improvement in SQ in patients using soft splints was observed in the 1st month and was maintained in the 2nd month.

CLINICAL RELEVANCE

This study provides insights on short-term clinical effects as regards to increased sleep quality and regulated maximum bite force as a function of splint material type and the thickness of the splint.

Frequency distribution of the number and amplitude of electromyographic waveforms of the masseter muscle during sleep in patients with a clinical diagnosis of sleep bruxism

OBJECTIVE

This study aimed to clarify frequency distribution of number and peak amplitude of electromyographic (EMG) waveforms of sleep bruxism (SB) in outpatients with clinical diagnosis of SB (probable bruxer: P-bruxer).

METHODS

Subjects were 40 P-bruxers. Masseteric EMG during sleep was measured at home using a wearable EMG system. EMG waveforms with amplitude of more than two times the baseline and with duration of 0.25 s were extracted as SB bursts. Clusters of bursts, i.e. SB episodes, were also scored.

RESULTS

There were large variations among the subjects in numbers of SB bursts and episodes and in burst peak amplitude. As for burst peak amplitude within a subject, a wide right-tailed frequency distribution was shown with the highest frequency at the class of 5-10% maximum voluntary contraction.

CONCLUSION

The number and amplitude of SB waveforms for P-bruxers were distributed over a wide range, indicating the existence of large individual differences.

Three-dimensional evaluation of sleep bruxism-related splint wear using a dental laboratory scanner: A preliminary clinical study

BACKGROUND

The wear depth on the occlusal splint (OS) is reportedly associated with the sleep bruxism (SB) level, as evaluated using portable polysomnography (PSG) recordings. However, the OS is deformed owing to SB forces, possibly preventing the accurate quantification of the wear facets.

OBJECTIVES

We aimed to introduce a newly developed system to quantify the wear facets on the OS using a dental laboratory scanner (D810) and investigate the association between the wear facets, as evaluated with this system, and the SB level.

METHODS

Ten healthy individuals who were diagnosed with SB based on portable PSG recordings participated in this study. They were asked to wear the OS for 2 months. The first day after a 2-week adaptation period was defined as the reference day, and sequential scanning of the OS surface was performed on days 15, 30, and 45. Changes in the OS surface from the reference day allowed dimensional evaluation of the wear facets in terms of maximum wear depth, wear area, and wear volume. Multiple regression analyses were conducted to test whether each of these variables could be predicted by any of the SB-related variables.

RESULTS

The total duration of SB episodes per hour of sleep and the maximum muscle activity were significantly associated with the wear area, as measured with our system (adjusted R-squared was .78, p < .01).

CONCLUSION

Our system allows dimensional analysis of the wear facets on the OS surface in association with the SB level.

Portable and wearable electromyographic devices for the assessment of sleep bruxism and awake bruxism: A literature review

OBJECTIVE

The current state of portable/wearable electromyographic (EMG) devices for assessment of bruxism was reviewed.

METHODS

A search of full-text articles relevant to portable/wearable EMG devices capable of being used at home was performed. The data source used was MEDLINE via PubMed from January 1970 to July 2019.

RESULTS

There were nine kinds of wearable EMG devices capable of being used under unrestrained conditions. Ultra-miniaturized wearable EMG devices with a level of performance equivalent to that of conventional stationary EMG devices have been developed and are being used during sleep and in the daytime. The devices have a high level of diagnostic accuracy for sleep bruxism. A definite cut-off value for awake bruxism has not been established.

DISCUSSION

Assessment of sleep bruxism with a high level of accuracy can be performed using a portable/wearable EMG device. However, a definite cut-off value is required for assessment of awake bruxism.

Efficacy of botulinum toxin type a in the targeted treatment of sleep bruxism: a double-blind, randomised, placebo-controlled, cross-over study

Background

Intramuscular injections of botulinum toxin A (BTX-A) have been used in the treatment of sleep bruxism (SB) however controlled trials are limited and the optimal injection strategy and dose is not known.

Methods

This double-blind, randomised, placebo-controlled, cross-over study evaluated the efficacy and safety of BTX-A in participants with SB. Average bruxism events per hour of sleep (Bruxism Index, BI) was calculated using surface electromyography. Participants with BI >5 were included and randomised by order of injection (active or placebo with the opposite 20 weeks later) and into one of three differing treatment groups: bilateral masseter (60 units(U)), bilateral masseter and temporalis (90U) and bilateral masseter, temporalis and medial pterygoid muscles (120U). Change in BI and subjective measures of headache, pain, and bruxism at 4 and 12 weeks was calculated following intervention, and differences between treatment groups analysed.

Results

41 participants were recruited, 35 randomised and data from 22 participants (14 female) were analysed. BI was significantly lower at 4 weeks after active treatment when compared with placebo (mean=−1.66, p=0.003), not sustained at 12 weeks. The difference was greater with higher doses injected and among those with greater baseline BI. There was no difference in subjective measures at any time point. Five participants injected had mild, transient side effects.

Discussion

Targeted BTX-A injection is a safe and effective treatment for SB. A greater benefit may be achieved by administering BTX-A into more muscles and at higher total doses and among those with higher baseline BI.

Trial registration number

ACTRN12618001430224.

Ultrasonographic evaluation of the effect of splint therapy on masseter muscle and blood flow in patients with bruxism

OBJECTIVE

To investigate the effect of splint therapy on masseter muscle and blood flow in patients with bruxism using ultrasonography (USG).

METHODS

Twenty female patients with bruxism receiving splint treatment were studied. Masseter thickness and elasticity were assessed using gray-scale USG and shear-wave elastography (kPa) at rest and maximum clenching. Blood flow parameters of external carotid artery (ECA), maxillary, facial, mental artery were examined using Doppler USG before and after splint application.

RESULTS

Thickness and elasticity of masseter muscle was statistically significantly decreased at rest after splint therapy (p < 0.05). Significant difference was determined only in some parameters of ECA and maxillary artery in Doppler USG before and after splint (p < 0.05); there was no difference for facial and mental artery (p > 0.05).

CONCLUSION

Thickness and elasticity of masseter muscle were significantly decreased after splint therapy. USG can measure muscle activity and blood flow in bruxism patients.

Oral appliances reduce masticatory muscle activity-sleep bruxism metrics independently of changes in heart rate variability

OBJECTIVES

Sleep bruxism (SB) is associated with physiological activities including sympathetic autonomic system dominance and sleep micro-arousal. While oral appliances (OA) are used to prevent SB harmful effects, the influence of OAs physiological mechanisms during sleep is unknown. The aim of this study is to assess whether heart rate variability (HRV) changes, as a marker of autonomic nervous system activity, would be associated with the OA mechanism of action on SB using occlusal splint (OS) and mandibular advancement splint (MAS).

MATERIALS AND METHODS

A retrospective analysis, from data previously collected in 21 participants with SB (25.6 ± 4.5 years) with polysomnographic recordings, was done. HRV data were compared between a reference night (no-device) and ones during which OS or MAS was used in a crossover study design. Rhythmic masticatory muscle activity (RMMA) index was compared between nights. HRV was evaluated using autoregressive model analysis for three sections: baseline (distance from RMMA), immediately before, and after RMMA period.

RESULTS

A significant reduction in RMMA index, when wearing OA during sleep, was observed (P < 0.01), but was not associated with HRV parameters change. HRV significantly changed after RMMA onset for nights with OA during non-REM sleep in comparison with baseline (P < 0.02).

CONCLUSIONS

The usage of OAs for SB participants reduced RMMA, but most likely independently of changes in HRV linked to the mechanism associated with SB genesis.

CLINICAL RELEVANCE

Wearing OA seems to reduce grinding noise and protect from dental injuries but does not seem to influence SB genesis.

Effects of stabilization splints on the signs and symptoms of temporomandibular disorders of muscular origin: A systematic review

OBJECTIVE

To assess effects of stabilization splints on signs and symptoms of temporomandibular disorders of muscular origin compared to other treatments.

METHODS

A search for articles via six electronic databases and gray literature was conducted. The risk of bias was evaluated with the Cochrane Collaboration tool. The Grading of Recommendations Assessment, Development and Evaluation approach determined the certainty of evidence.

RESULTS

Ten articles were included. Stabilization splints (n = 160 subjects) were reported to be as effective as other treatments (n = 209 patients) on analyzed outcomes (pressure pain threshold, pain during chewing, mouth opening, spontaneous pain intensity and by palpation). Five studies were judged at low and five at some concerns of risk of bias. The certainty of evidence was very low for all outcomes.

CONCLUSION

Positive effect on signs and symptoms of temporomandibular disorders of muscular origin, when managed with stabilization splint, could not be confirmed or refuted.

Efficacy of botulinum-A for nocturnal bruxism pain and the occurrence of bruxism events: a meta-analysis and systematic review

The purpose of this study was to explore the treatment efficacy of botulinum-A (BTX-A) in nocturnal bruxism. Five electronic databases (PubMed, Web of Science, Cochrane, Embase and Clinical Trials) were searched to identify related randomised controlled trials up to September 1, 2020. Five evaluation indices were extracted, namely, the pain at rest and at chewing (PR and PC), the number of bruxism events (NBE) and the self-assessment by patients (SA), to assess the treatment efficacy of BTX-A in bruxism. All data analyses were conducted using Review Manager (Version 5.3; The Cochrane Collaboration, London, United Kingdom). Six studies were included in this review. The sample was composed of 148 participants. Compared with the placebo group, the BTX-A group showed the significantly improved the PR index scores (MD, 1.16 cm; 95%CI, 0.65 to 1.67 cm; p < 0.00001), slightly improved the PC index scores (SMD, 0.25; 95%CI -0.14 to 0.64; p = 0.21), and the NBEs were significantly decreased in the before-injection group compared with that in the after-injection group (MD, 1.72; 95%CI, 0.60 to 2.85; p = 0.003). The results of this study suggest that BTX-A possesses significant therapeutic efficiency for the relief of pain and events of bruxism. However, whether the events of bruxism would recur or rebound after botulinum toxin injection needs more follow-up clinical evidence.

A pilot study to test the validity of a piezoelectric intra-splint force detector for monitoring of sleep bruxism in comparison to portable polysomnography

PURPOSE

To test the validity of a force-based detection system (ISFD: intra-splint force detector) to record sleep bruxism (SB) in comparison to portable polysomnography (PSG).

METHODS

Simultaneous portable PSG recordings with a masseter electromyography (EMG) channel and ISFD with a deformation-sensitive piezoelectric film were performed on six participants with definite SB. First, simulated bruxism behaviors (static clenching, grinding, tapping, and rhythmic clenching) were recorded using both EMG and ISFD. Using these data, interval and duration criteria for ISFD data conditioning were established. Then, portable PSG recordings were conducted with the ISFD during sleep. Using the above criteria, ISFD events were compared with EMG-based SB episodes (the gold standard), and the sensitivity and positive predictive value of ISFD events were calculated. Spearman's correlation coefficients between true-positive ISFD events and SB episodes were then calculated.

RESULTS

Among the tested conditioning criteria, a 3-s interval combined with a 1-s duration was selected. The median sensitivity and positive predictive value for the ISFD were 0.861 and 0.585, respectively. The duration of true-positive ISFD events was correlated with that of EMG-based SB episodes (rho = 0.658, P < 0.01).

CONCLUSION

ISFD has validity for SB detection and could be an alternative to single-channel EMG-based recordings.

Effects of vibratory feedback stimuli through an oral appliance on sleep bruxism: a 6-week intervention trial

PURPOSE

Various biofeedback stimulation techniques of managing sleep bruxism (SB) have recently emerged; however, the effect of successive application of vibratory feedback stimulation has not been clarified. This study elucidated the effect of vibration feedback stimulation via an oral appliance (OA) on SB when vibration feedback was applied for 4 weeks.

METHODS

This was a prospective, single-arm, open-label, intervention study. Ten participants diagnosed with "definite" SB wore a specially designed OA for 45 nights in a home-setting. A force-based SB detection system, including a pressure-sensitive piezoelectric film placed internally in the OA, triggered a vibrator attached to the OA. Vibratory stimulation was withheld during the first 2-week adaptation period (1st-15th nights), applied during the 4-week stimulation period (16th-43rd nights), and again withheld during the post-stimulation period (44th and 45th nights). The number and duration of SB episodes/hour of sleep were calculated based on masseter electromyographic activity recorded with in-home portable polysomnography and compared between the 15th and 45th nights (without stimulation) and the 17th and 43rd nights (with stimulation).

RESULTS

The number and duration of SB episodes significantly decreased after vibratory stimulation (15th vs. 17th nights: p = 0.012 and p = 0.012, respectively), then significantly increased upon cessation of vibratory stimulation after the stimulation period (43rd vs. 45th nights: p = 0.023 and p = 0.023, respectively).

CONCLUSION

Contingent vibratory stimulation through an OA may suppress SB-related masticatory muscle activity continuously for 4 weeks and may be an effective alternative for the management of SB.

TRIAL REGISTRATION

https://jrct.niph.go.jp/ ; trial registration number: jRCTs032190225.

Effect of contingent vibratory stimulus via an oral appliance on sleep bruxism after the splint adaptation period

BACKGROUND

Contingent vibratory feedback stimuli applied by a specially designed oral appliance (OA) have been reported to be effective in reducing sleep bruxism (SB). However, the inhibitory effects of the OA, which occur immediately after OA delivery, may have confounded this finding.

OBJECTIVE

This study sought to shed light on the effects of vibratory stimuli on SB after the OA adaptation period, when its inhibitory effects are diminished.

METHODS

Fourteen 'definite' SB patients were enrolled. A force-based bruxism detection system was utilised to trigger a vibrator attached to the OA. Masseter electromyographic activity during sleep was recorded at home using portable polysomnography. After using the OA without vibratory stimulus for 16 nights (adaptation period), intermittent vibratory stimuli were applied every other half-hour for four nights (intervention period). Electromyographic activity over 10% of the maximum voluntary contraction was regarded as a SB episode. The number and the total duration of SB episodes per hour of sleep were calculated for the sessions with and without stimuli separately and averaged for four intervention nights. The effects of stimuli on these two variables were evaluated.

RESULTS

The number and the total duration of the sessions without stimuli were 5.2 episodes/h and 35.3 s/h, respectively. These values significantly decreased to 3.9 episodes/h and 15.1 s/h (p < .05) for the sessions with vibratory stimuli.

CONCLUSION

Contingent vibratory stimulus via an OA may be effective for the management of SB even after adaptation to OA.

Signal acquisition and analysis of ambulatory electromyographic recordings for the assessment of sleep bruxism: A scoping review

Background

Ambulatory electromyographic (EMG) devices are increasingly being used in sleep bruxism studies. EMG signal acquisition, analysis and scoring methods vary between studies. This may impact comparability of studies and the assessment of sleep bruxism in patients.

Objectives

(a) To provide an overview of EMG signal acquisition and analysis methods of recordings from limited‐channel ambulatory EMG devices for the assessment of sleep bruxism; and (b) to provide an overview of outcome measures used in sleep bruxism literature utilising such devices.

Method

A scoping review of the literature was performed. Online databases PubMed and Semantics Scholar were searched for studies published in English until 7 October 2020. Data on five categories were extracted: recording hardware, recording logistics, signal acquisition, signal analysis and sleep bruxism outcomes.

Results

Seventy‐eight studies were included, published between 1977 and 2020. Recording hardware was generally well described. Reports of participant instructions in device handling and of dealing with failed recordings were often lacking. Basic elements of signal acquisition, for example amplifications factors, impedance and bandpass settings, and signal analysis, for example rectification, signal processing and additional filtering, were underreported. Extensive variability was found for thresholds used to characterise sleep bruxism events. Sleep bruxism outcomes varied, but typically represented frequency, duration and/or intensity of masticatory muscle activity (MMA).

Conclusion

Adequate and standardised reporting of recording procedures is highly recommended. In future studies utilising ambulatory EMG devices, the focus may need to shift from the concept of scoring sleep bruxism events to that of scoring the whole spectrum of MMA.

The efficacy of occlusal splints in the treatment of bruxism: A systematic review

OBJECTIVES

Bruxism is a commonly reported oral parafunctional activity characterised by excessive tooth grinding or clenching outside normal functional activity. The present systematic review aims to examine the available literature to determine the effectiveness of occlusal splints in the treatment of bruxism compared to no treatment and alternative treatment modalities.

DATA

Data extraction was undertaken in conjunction with quality of evidence assessment.

SOURCES

A literature search of the following databases was undertaken: MEDLINE via OVID, Pubmed (Medline), Cochrane Oral Health Group's Trials, The Cochrane Central Register of Controlled Trials and EMBASE.

STUDY SELECTION

Randomised Controlled Trials (RCT) and quasi-RCTs which met the inclusion criteria were selected for analysis. These included studies comparing occlusal splints to no treatment or other interventions.

RESULTS

Twenty-two studies were identified for review with fourteen meeting the inclusion criteria. Only a small number of studies were available in each comparison (one or two for some) all of which had a medium to high risk of bias.

CONCLUSIONS

There is insufficient evidence to determine whether occlusal splint therapy for the treatment of bruxism provides a benefit over no treatment, other oral appliances, TENS, behavioural or pharmacological therapy. Furthermore, there is a lack of studies in each comparison with many suffering from a high risk of bias. There is a need for further research in this area and improvement in trial quality.

CLINICAL SIGNIFICANCE STATEMENT

This systematic review aimed to determine the effectiveness of occlusal splints in the treatment of bruxism. It found there was insufficient evidence to recommend occlusal splint therapy over no treatment or other treatment modalities. This is relevant to dental clinicians who may provide such appliances and cautions them in treatment provision.

Long-term effects of splint therapy in patients with posttraumatic stress disease (PTSD)

Objectives

The aim of a pilot study was to clarify the question of whether mouth opening restrictions in patients with PTSD by means of splint therapy (st) show long-term therapeutic effects in the case of functional disorders.

Material and methods

In 31 of 36 inpatients (soldiers, average age 37.1 ± 7.3 years, 26.7 ± 2.1 teeth) with confirmed posttraumatic stress disorder, chronic pain intensity > 6 (visual analogue scale 0 to 10), the mouth opening was determined, and the functional status (RDC-TMD) was recorded. All participants received a splint that was worn at night. A control of the therapeutic effect of the splint occurred after 6 weeks, 3, 6, and 12 months.

Results

The mouth opening initially had an average of 30.9 ± 6.5 mm (median 31 mm). The pain intensity (PI) was reported to be on average VAS 8.3 ± 0.9, the chronic degree of pain according to von Korff was 3.9 ± 03. Six weeks after the st (n = 31), the average mouth opening was 49.5 ± 6.3 mm (median 51.5). PI was given as VAS 2.3 ± 1.1 on average. After 3, 6, and 12 months, 24, 15, and 14 subjects could be interviewed regarding PI. Based on the last examination date of all subjects, the average PI was given as 1.1 ± 0.9 (median 1).

Conclusion

The presented data show that the therapeutic short-term results achieved by means of a splint remain valid on the long term despite continued PTSD.

Clinical relevance

The presented study shows that patients will benefit in the long term from a splint and remain symptom-free, even if this mental illness persists.

Intelligent Occlusion Stabilization Splint with Stress-Sensor System for Bruxism Diagnosis and Treatment

Bruxism is a masticatory muscle activity characterized by high prevalence, widespread complications, and serious consequences but without specific guidelines for its diagnosis and treatment. Although occlusal force-based biofeedback therapy is proven to be safe, effective, and with few side effects in improving bruxism, its mechanism and key technologies remain unclear. The purpose of this study was to research a real-time, quantitative, intelligent, and precise force-based biofeedback detection device based on artificial intelligence (AI) algorithms for the diagnosis and treatment of bruxism. Stress sensors were integrated and embedded into a resin-based occlusion stabilization splint by using a layering technique (sandwich method). The sensor system mainly consisted of a pressure signal acquisition module, a main control module, and a server terminal. A machine learning algorithm was leveraged for occlusal force data processing and parameter configuration. This study implemented a sensor prototype system from scratch to fully evaluate each component of the intelligent splint. Experiment results showed reasonable parameter metrics for the sensors system and demonstrated the feasibility of the proposed scheme for bruxism treatment. The intelligent occlusion stabilization splint with a stress sensor system is a promising approach to bruxism diagnosis and treatment.

Effects of invisible orthodontic retainers on masticatory muscles activity during sleep: a controlled trial

BACKGROUND

This study aims to evaluate if invisible orthodontic retainers can affect sleep-time masticatory muscle activity (sMMA) over a short-term period in healthy individuals.

METHODS

Nineteen (N = 19) healthy subjects underwent an in-home evaluation with a portable device for electromyographic (EMG) assessment. The study protocol provided two baseline recording nights, a night off, and then two additional nights with passive customized orthodontic retainers in situ. For each recording night, the sleep bruxism (SB) index (i.e., average number of SB events/hour) and the overall number of masseter muscle contractions were assessed. Comparison between values gathered over the four recording nights was made with a parametric test, based on the null hypothesis that there was no difference between wearing or not wearing the retainers as far as the sMMA variables are concerned.

RESULTS

Average SB index of the first two nights without the retainers was 3.0 ± 1.5, whilst the average values with the retainers in situ was 3.6 ± 1.9. ANOVA test showed the absence of significant differences between the four nights. Similarly, no differences were shown between the four nights as for the total number of sMMA events. Based on that, the null hypothesis was not rejected.

CONCLUSIONS

Findings suggest the absence of relevant effects of invisible orthodontic retainers on sMMA in healthy individuals during the short-term period.

Evidence-Based Support for Sleep Bruxism Treatment Other Than Oral Appliances Remains Insufficient

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Management of sleep bruxism in adults: A qualitative systematic literature review. Manfredini D, Ahlberg J, Winocur E, Lobbezoo F. J Oral Rehab 2015;42:862-74.

SOURCE OF FUNDING

The authors declare that they did not receive any financial support for this article TYPE OF STUDY/DESIGN: Systematic review.

Evaluation of sleep bruxism with a novel designed occlusal splint

PURPOSE

This report presents our evaluation system that assesses sleep bruxism. The characteristics and fabrication process of our novel designed splint, and the analysis process of our system are presented.

METHODS

The subjects were 17 volunteers. The splint was fabricated with a self-curing resin compounded with an amino-acid powder for easy wear on the semi-adjustable articulator, and adjusted for a full-balanced occlusion. An impression of the splint, located on the cast, was taken before and after it was worn. The analytical casts were made and scanned via a dental 3D scanner. The datasets were superimposed using two kinds of regions of interest (palate and occlusal surface). The differences between the two datasets were quantitatively presented with pseudo-color mapping. The maximum differences in coronal and apical directions were calculated on the selected area in the occlusal surface when the occlusal surface was used as a region of interest for registration. The relationship between the EMG activities and the change of occlusal surface of the splint were investigated.

RESULTS

In all subjects, deformation and wear facets on the splint were observed. The differences in the apical direction, which indicate wear depth, were correlated with the maximum muscle activity during sleep (p=0.036).

CONCLUSION

From our results, it is suggested that we are not able to eliminate the influence of parafunction for the prosthesis only by designing the surface of occlusal splint using the semi-adjustable articulator. Our splint may have the potential to detect specific facets due to parafunctions as nocturnal bruxism.

Sleep bruxism: Current knowledge and contemporary management

Bruxism is defined as the repetitive jaw muscle activity characterized by the clenching or grinding of teeth. It can be categorized into awake and sleep bruxism (SB). Frequent SB occurs in about 13% of adults. The exact etiology of SB is still unknown and probably multifactorial in nature. Current literature suggests that SB is regulated centrally (pathophysiological and psychosocial factors) and not peripherally (morphological factors). Cited consequences of SB include temporomandibular disorders, headaches, tooth wear/fracture, implant, and other restoration failure. Chairside recognition of SB involves the use of subjective reports, clinical examinations, and trial oral splints. Definitive diagnosis of SB can only be achieved using electrophysiological tools. Pharmacological, psychological, and dental strategies had been employed to manage SB. There is at present, no effective treatment that “cures” or “stops” SB permanently. Management is usually directed toward tooth/restoration protection, reduction of bruxism activity, and pain relief.

Management of sleep bruxism in adults: a qualitative systematic literature review

This paper updates the bruxism management review published by Lobbezoo et al. in 2008 (J Oral Rehabil 2008; 35: 509-23). The review focuses on the most recent literature on management of sleep bruxism (SB) in adults, as diagnosed with polysomnography (PSG) with audio-video (AV) recordings, or with any other approach measuring the sleep-time masticatory muscles' activity, viz., PSG without AV recordings or electromyography (EMG) recorded with portable devices. Fourteen (N = 14) papers were included in the review, of which 12 were randomised controlled trials (RCTs) and 2 were uncontrolled before-after studies. Structured reading of the included articles showed a high variability of topics, designs and findings. On average, the risk of bias for RCTs was low-to-unclear, whilst the before-after studies had several methodological limitations. The studies' results suggest that (i) almost every type of oral appliance (OA) (seven papers) is somehow effective to reduce SB activity, with a potentially higher decrease for devices providing large extent of mandibular advancement; (ii) all tested pharmacological approaches [i.e. botulinum toxin (two papers), clonazepam (one paper) and clonidine (one paper)] may reduce SB with respect to placebo; (iii) the potential benefit of biofeedback (BF) and cognitive-behavioural (CB) approaches to SB management is not fully supported (two papers); and (iv) the only investigation providing an electrical stimulus to the masseter muscle supports its effectiveness to reduce SB. It can be concluded that there is not enough evidence to define a standard of reference approach for SB treatment, except for the use of OA. Future studies on the indications for SB treatment are recommended.