The bruxism construct: From cut‐off points to a continuum spectrum

This commentary discusses the need to move on from the adoption of cut‐off points for the definition of the presence/absence of bruxism and justifies the need to embrace an evaluation based on the continuum of jaw motor behaviours. Currently, the number of events per hour, as identified by polysomnography (PSG), is used to define the presence of sleep bruxism (SB). Whilst PSG still remains the indispensable equipment to study the neurophysiological correlates of SB, the scoring criteria based on a cut‐off point are of questionable clinical usefulness for the study of oral health outcomes. For awake bruxism (AB), criteria for a definite diagnosis have never been proposed. Some goal‐oriented strategies are proposed to identify bruxism behaviours that increase the risk of negative oral health outcomes (eg, tooth wear, muscle and/or temporomandibular joint [TMJ] pain, restorative complications). One possible strategy would embrace an improved knowledge on the epidemiology and natural variability of bruxism, even including study of the amount of PSG/SB and electromyography masticatory muscle activity (EMG/MMA) during sleep and the frequency/prevalence of bruxism behaviours during wakefulness that are needed to represent a risk factor for clinical consequences, if any. There should not be any preclusion about the diagnostic strategies to pursue that goal, and a combination of instrumental and non‐instrumental approaches may even emerge as the best available option. Once data are available, large‐scale, non‐selected population samples representing the entire continuum of EMG/MMA activities are also needed, in the attempt to estimate untreated health risks in the population.     

Oral mixing ability and cognition in elderly persons with dementia: A cross‐sectional study

Masticatory performance has been positively associated with cognitive ability in both animals and healthy humans. We hypothesised that there would also be a positive correlation between masticatory performance and cognition in older persons suffering from dementia. Older persons suffering from dementia (n = 114) and receiving institutionalised care were studied in a cross‐sectional design. The assessments included masticatory performance, which was measured objectively with a two‐colour gum mixing ability test, and cognition, which was assessed with a multidomain neuropsychological test battery. Significant relationships were observed between masticatory performance and general cognition and between masticatory performance and verbal fluency. Hierarchical regression analysis revealed that the correlation with general cognition was influenced by the scores for dependency in activities of daily living. The association between verbal fluency and masticatory performance was not significantly affected by secondary variables. An unexpected limitation of this study was the high dropout rate for the mixing ability test. The clinical implications of these findings are profound; care professionals should endeavour to maintain and stimulate mastication in older persons with dementia in an attempt to preserve cognition.     

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.     

Validity of the Oral Behaviours Checklist: correlations between OBC scores and intensity of facial pain

The first purpose of this study was to translate the Oral Behaviours Checklist (OBC) into Dutch and to examine its psychometric properties. The second purpose was to examine the correlations between scores on the OBC and facial pain, while controlling for the possible confounding effects of psychosocial factors, such as stress, depression, somatisation and anxiety. The OBC was translated, following the international RDC/TMD consortium guidelines. Its psychometric properties were examined by assessing the test–retest reliability and concurrent validity [correlations between the OBC and the previously developed Oral Parafunctions Questionnaire (OPQ)]. Participants were 155 patients with TMD (77% female; mean age and s.d. = 43·6 and 14·4 years). The translation of the OBC into Dutch proceeded satisfactorily. The psychometric properties of the Dutch OBC were good; test–retest reliability was excellent (ICC = 0·86, P < 0·001). Concurrent validity was good: the correlation between the OBC and OPQ was high (r = 0·757, P < 0·001), while the correlations between individual items ranged from 0·389 to 0·892 (P < 0·001). Similar to previous Dutch studies using the OPQ, no significant correlation was found between oral parafunctions and facial pain (r = 0·069, P = 0·892). No significant correlations could be found between oral parafunctional behaviours and facial pain.     

Correlation between self‐reported and clinically based diagnoses of bruxism in temporomandibular disorders patients

The present investigation was performed in a population of patients with temporomandibular disorders (TMD), and it was designed to assess the correlation between self‐reported questionnaire‐based bruxism diagnosis and a diagnosis based on history taking plus clinical examination. One‐hundred‐fifty‐nine patients with TMD underwent an assessment including a questionnaire investigating five bruxism‐related items (i.e. sleep grinding, sleep grinding referral by bed partner, sleep clenching, awake clenching, awake grinding) and an interview (i.e. oral history taking with specific focus on bruxism habits) plus a clinical examination to evaluate bruxism signs and symptoms. The correlation between findings of the questionnaire, viz., patients' report, and findings of the interview/oral history taking plus clinical examination, viz., clinicians' diagnosis, was assessed by means of φ coefficient. The highest correlations were achieved for the sleep grinding referral item (φ = 0·932) and for the awake clenching item (φ = 0·811), whilst lower correlation values were found for the other items (φ values ranging from 0·363 to 0·641). The percentage of disagreement between the two diagnostic approaches ranged between 1·8% and 18·2%. Within the limits of the present investigation, it can be suggested that a strong positive correlation between a self‐reported and a clinically based approach to bruxism diagnosis can be achieved as for awake clenching, whilst lower levels of correlation were detected for sleep‐time activities.     

Comparison of wear between occlusal splint materials and resin composite materials

Tooth wear in bruxing patients often results in a need for treatment with composite restorations. In some cases, bruxing patients receive an occlusal splint as a protective means as well. However, the wear between these opposing materials has not been investigated yet. The aim of this in vitro study was to assess the wear of different splint materials against resin composite materials. A two‐body wear test was conducted using the ACTA wear machine. The materials selected for this study were three composites used for direct restorations (Filtek Z250, CLEARFIL AP‐X, and Filtek Supreme XT) and four occlusal splints materials, viz. a polyamide resin (ThermoSens) an conventional (hand‐processed), milled and printed polymethylmethacrylate (PMMA). As antagonistic materials, stainless steel, Filtek Supreme XT and CLEARFIL AP‐X were used. The wear rate of the seven materials was determined after 200 000 cycles, using a profilometry. The rates were analysed using two‐way ANOVA and post hoc Tukey's tests. The wear rates were significantly higher for the conventional and milled PMMA materials than for all other materials (P < .001). The wear rates of printed PMMA and the polyamide resin were comparable to composite wear rates. The antagonist materials have minor or no influence on the amount of wear of the various splint materials (P < .001). In conclusion, different splint materials yielded different wear rates for all antagonist materials tested. Keeping in mind that this study is an experimental in vitro study, this finding enables practitioners to choose the splint material necessary according to their patients’ needs.     

The outcome of a temporomandibular joint compression test for the diagnosis of arthralgia is confounded by concurrent myalgia

Clinical Oral Investigations - Pain in the orofacial region may originate from different structures, and one challenge for the clinician is to determine the primary origin of pain reported by the...