Bruxism is a much-discussed clinical issue in dentistry. Although bruxism is not a life-threatening disorder, it can influence the quality of human life, especially through dental problems, such as tooth wear, frequent fractures of dental restorations and pain in the oro-facial region. Therefore, various clinical methods have been devised to assess bruxism over the last 70 years. This paper reviews the assessment of bruxism, provides information on various assessment methods which are available in clinical situations and discusses their effectiveness and usefulness. Currently, there is no definitive method for assessing bruxism clinically that has reasonable diagnostic and technical validity, affects therapeutic decisions and is cost effective. One future direction is to refine questionnaire items and clinical examination because they are the easiest to apply in everyday practice. Another possible direction is to establish a method that can measure actual bruxism activity directly using a device that can be applied to patients routinely. More clinical studies should examine the clinical impact of bruxism on oral structures, treatment success and the factors influencing the decision-making process in dental treatment.

This study investigated the effect of stabilization splint (SS) and palatal splint (PS), which had the same design as SS except for the elimination of the occlusal coverage, on sleep bruxism (SB) using a portable electromyographic (EMG) recording system. Sixteen bruxers participated in this study. The EMG activities of the right masseter muscle during sleep were recorded for three nights each in the following five recording periods: before, immediately after, and 2, 4 and 6 weeks after the insertion of the splint. The crossover design, in which each splint was applied to each subject for 6 weeks with an interval of 2 months for a washout period, was employed in this randomized-controlled study. The number of SB events, duration and total activities of SB were analysed. The number of SB events before the insertion of splints (baseline) was 2.98 +/- 1.61 times h(-1). Both splints significantly reduced SB immediately after the insertion of devices (P < 0.05, one-way repeated-measures anova followed by Dunnett); however, no reduction was observed in 2, 4 or 6 weeks (P > 0.05). There was no statistical difference in the effect on SB between the SS and PS (P > 0.05, two-way repeated-measures anova). Both splints reduced the masseter EMG activities associated with SB; however, the effect was transient.

This narrative review explores the extent of the current knowledge of soft tissue barriers around implants from both a basic and clinical perspective, and aims to consolidate this knowledge and highlight the most pertinent questions relating to this area of research.

The bone quality evaluated by specific CBCT showed a high correlation with the primary stability of the implants. Hence, preoperative density value estimations by CBCT may allow clinicians to predict implant stability. Whether the density values obtained by the CBCT device used in the present study could be applied to other devices requires further elucidation.

This randomised controlled study investigated the effect of intermittent use of occlusal splints on sleep bruxism compared with that of continuous use by measuring masseter muscle electromyographic activity using a portable electromyographic recording system. Twenty bruxers were randomly allocated to the continuous group and intermittent group. Subjects in the continuous group wore stabilisation splints during sleep for 29 nights continuously, whereas those in the intermittent group wore splints during sleep every other week, that is they used splints on the 1st-7th, 15th-21st and 29th nights. Electromyographic activity of the masseter muscle during sleep was recorded for the following six time points: before (baseline), immediately after, and 1, 2, 3 and 4 weeks after the insertion of a stabilisation splint. The number of nocturnal masseter electromyographic events, duration and the total activity of sleep bruxism were analysed. In the continuous group, nocturnal masseter electromyographic events were significantly reduced immediately and 1 week after the insertion of the stabilisation splint, and duration was reduced immediately after the insertion (P < 0·05, Dunnett's test), but no reduction was observed at 2, 3 and 4 weeks after insertion. In the intermittent group, nocturnal masseter electromyographic events and duration were significantly reduced immediately after and also 4 weeks after insertion of the stabilisation splint (P < 0·05, Dunnett's test). The obtained results of the present exploratory trial indicate that the intermittent use of stabilisation splints may reduce sleep bruxism activity for a longer period compared with that of continuous use.

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Statins are cholesterol-lowering drugs that have been reported to promote bone formation. The purpose of this study was to investigate the effect of simvastatin on the enhancement of bone formation around titanium implants. Thirty-week-old female rats received pure titanium implants in both tibiae. The animals were intra-peritoneally administered 0, 0.125, 1, 5 or 10 mg kg(-1) of simvastatin daily. After 30 days, the animals were sacrificed, and specimens were prepared. The bone contact ratio of the implant, bone density in the medullary canal and percentage of cortical bone were obtained. Markers for bone turnover were also measured using sera collected at the time of euthanasia. In the medullary canal, a scanty amount of bone was observed in the 0, 0.125 and 1 mg kg(-1) groups. In contrast, in both the 5 and 10 mg kg(-1) groups, thicker bone trabeculae were abundant. Histometric observations showed that the bone contact ratio and the bone density of both groups were significantly greater than those of the other groups (anova, P < 0.01). However, no significant difference in the percentage of cortical bone was found between groups. Serum chemistry showed that statin increased bone formation markers and decreased bone resorption markers. In conclusion, although the dose equivalent to that used in human patients with hypercholesterolemia was not effective, a simvastatin dose of 5 mg kg(-1) or higher increased medullary bone formation around the titanium. In contrast, no effect of simvastatin on pre-existing cortical bone was indicated.

This retrospective study analyzed clinical outcomes of monolithic zirconia restorations (MZRs) and factors related to restoration success. Patient records were searched to identify those provided MZRs (Cercon ht) for premolars or molars between April 2012 and March 2016. All MZRs were placed according to a standardized protocol. Kaplan-Meier analysis was used to assess MZR performance and failure after recall appointments at 1 year or later. In total, 101 patients received 148 MZRs. Mean duration of follow-up was 25.0 ± 9.9 months. Six MZRs required replacement: three because of pulpal complications, one because of root fracture of an abutment tooth, one because of restoration fracture, and one because the tooth was used as an abutment tooth for a fixed partial denture after root fracture of an adjacent tooth. The cumulative MZR survival (success) rate at 3.5 years was 91.5% (95% confidence interval, 82.1% to 100%). The findings of this short-term retrospective study indicate that posterior MZRs are a therapeutic option for certain patients. In addition, several clinical procedures contribute to MZR success, including preparation design and occlusal and adhesive surface treatments.