This study investigated the diagnostic accuracy of Sleep Profiler, which relies on ambulatory polysomnography (PSG) with electroencephalogram for sleep bruxism (SB) and examined its episode-by-episode agreement in comparison to PSG equipped with audiovisual recordings (avPSG). This prospective 2-gate study recruited 10 individuals with probable SB and 10 healthy volunteers. Overnight experimental recordings were performed simultaneously using the ambulatory PSG with masseter electromyography and avPSG with masseter and temporalis electromyography. Sleep staging was performed manually for avPSG and automatically or manually for ambulatory PSG. SB episodes were manually scored based on electromyography signals with reference to sleep stages. The episode-by-episode agreement was analyzed by setting avPSG as the reference standard. The sensitivity, specificity, and accuracy for the diagnosis of SB were calculated after optimizing the cutoff values of the episode index and the burst index. Regarding the episode-by-episode agreement, median sensitivities were 0.825 and positive predictive values were approximately 0.6, regardless of the sleep staging procedure, indicating that approximately 40% of the overall total SB episodes scored by the ambulatory PSG were false positives. Because of overestimation of SB episodes, the optimal cutoff values for the episode index and the burst index were approximately 1.5 times higher than the avPSG-based cutoff values and dramatically improved the diagnostic precision metrics for the ambulatory PSG. Sleep Profiler can eliminate events during wakefulness by electroencephalogram and may provide a definitive diagnosis in patients with possible SB by applying optimized cutoff values. However, the risk of overestimation must be recognized. Registry: UMIN Clinical Trials Registry; Name: Accuracy of Portable PSG Device for Detection of Sleep Bruxism-Related Masseter EMG Muscle Activity; URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000037380; Identifier: UMIN000032793. Abe Y, Nakazato Y, Takaba M, Kawana F, Baba K, Kato T. Diagnostic accuracy of ambulatory polysomnography with electroencephalogram for detection of sleep bruxism-related masticatory muscle activity. J Clin Sleep Med. 2023;19(2):379-392.

Sleep bruxism (SB) is a sleep-related movement disorder characterized by grinding and clenching of the teeth during sleep. We previously found a significant association between SB and a single nucleotide polymorphism (SNP), rs6313, in the neuronal serotonin 2A receptor gene (HTR2A), and established human induced pluripotent stem cell (iPSC)-derived neurons from SB patients with a genetic variant. To elucidate the electrophysiological characteristics of SB iPSC-derived neural cells bearing an SB-related genetic variant, we generated ventral hindbrain neurons from SB patients and unaffected controls, and explored the intrinsic membrane properties of these neurons using the patch-clamp technique. We found that the electrophysiological properties of iPSC-derived neurons mature in a time-dependent manner in long-term control cultures. SB neurons exhibited higher action potential firing frequency, higher gain, and shorter action potential half duration. This is the first in vitro modeling of SB using patient-specific iPSCs. The revealed electrophysiological characteristics may serve as a benchmark for further investigation of pathogenic mechanisms underlying SB. Moreover, our results on long-term cultures provide a strategy to define the functional maturity of human neurons in vitro, which can be implemented for stem cell research of neurogenesis, and neurodevelopmental disorders.

Background/purpose: In cases of missing posterior teeth, treatment modalities based on the shortened dental arch (SDA) concept may be a viable alternative. However, the association between oral health-related quality of life (OHRQoL) and patients' treatment decisions remains unclear. This study aimed to investigate the association between OHRQoL and the decision to be treated with implant-supported fixed partial dentures (IFPDs) or take a wait-and-see approach in patients with an SDA missing a single second molar and to clarify the impact of IFPD treatment on the OHRQoL. Materials and methods: The Oral Health Impact Profile (OHIP) questionnaire was administered twice (pre- and post-treatment) and once to 41 patients with a unilateral SDA missing a single second molar who chose IFPD treatment (IFPD group, n = 22) and the wait-and-see approach (no treatment group, n = 19), respectively. Logistic regression analysis was performed with IFPD treatment choice as the objective variable and the four OHIP dimension scores, age, and sex as covariates. The pre- and post-treatment values of the OHIP summary and four-dimension scores were compared using a paired t-test. Results: The IFPD treatment choice was significantly associated with sex (male), higher Oral Function dimension scores, and lower Psychosocial Impact dimension scores (all P < 0.05). The OHIP summary and four-dimension scores were significantly lower following IFPD treatment (all P < 0.05). Conclusion: IFPD treatment for a single missing second molar may be clinically beneficial for improving the OHRQoL of patients with an SDA who experience a decline in masticatory function.

Background Previous studies have suggested that providing dietary guidance along with denture treatment may improve dietary diversity in edentulous patients; however, none have examined the effects on nutritional blood biomarkers. This study investigated the effects of individualized dietary guidance combined with complete denture treatment on nutritional blood biomarker levels, dietary intake, and masticatory function. Materials and methods This was a prospective, randomized, open-label, controlled trial. Patients seeking new dentures with at least one edentulous arch were randomly allocated to Group A (denture treatment only) or Group B (dietary guidance followed by denture treatment). Individualized dietary guidance was provided exclusively to Group B by dentists based on baseline assessments. Baseline and post-treatment assessments included blood tests, a dietary survey using the Brief-type Self-Administered Diet History Questionnaire (BDHQ), occlusal force measurements using pressure-sensitive film, and masticatory performance tests using gummy jelly. The results from the baseline and post-treatment assessments were compared within each group, and exploratory comparisons of changes were conducted between groups. Results A total of 39 individuals completed the protocol (20 in Group A and 19 in Group B; mean age 73.4 ± 10.6 years; 17 males, 22 females). Both groups showed a significant increase in occlusal force after treatment (P = 0.007 for Group A; P = 0.011 for Group B), while no improvement in blood biomarkers was observed. In Group B, the intake of fish with bones (P = 0.035) and non-oily fish (P = 0.030), as evaluated using the BDHQ, significantly increased after treatment. Group B also showed significantly greater increases than Group A in methionine (P = 0.012), lysine (P = 0.048), and total essential amino acids (P = 0.029), as evaluated by blood tests, as well as the intake of fish with bones (P = 0.043). Conclusion Although denture treatment may increase occlusal force, combining dietary guidance with prosthetic treatment appears to further enhance dietary habits and support the nutritional status of edentulous patients.

Background/purpose: Implant-supported fixed partial dentures (IFPDs) are a treatment option for partially edentulous dentition with missing posterior-most molars despite the concept of a shortened dental arch (SDA). This study aimed to evaluate the effect of IFPD treatment on oral health-related quality of life (OHRQoL) in patients with unilateral SDA missing two adjacent molars and to compare the effects of single- and twounit IFPDs. Materials and methods: Forty patients with unilateral SDA missing two adjacent molars (Kennedy Class II) participated in this study; 11 patients received one implant placement in the first molar and were treated with a single -unit IFPD (single -unit group), and 29 received two implant placements and were treated with a two-unit IFPD (two-unit group). The Oral Health Impact Profile (OHIP) questionnaire for OHRQoL assessment and the gummy jelly test for objective masticatory performance were administered before and after IFPD treatment. The Wilcoxon signed-rank test for all patients and Mann - Whitney U test were performed for pre- and post-treatment comparisons and between-group comparisons, respectively. Results: The OHIP summary score and gummy jelly glucose concentration in all patients showed significant improvements after treatment (all P < 0.05). No significant differences were observed between the single- and two-unit groups for any of the items. Using the minimal important difference in the OHIP summary score, 63.6 % and 58.6 % of patients in the single- and two-unit groups, respectively, showed improvement by 6 points or more. Conclusion: IFPD treatment for patients with SDA missing two adjacent molars may provide clinically meaningful improvements in OHRQoL. (c) 2024 Association for Dental Sciences of the Republic of China. Publishing services by Else- vier B.V. This is an open access article under the CC BY -NC -ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Background/purpose: Various biofeedback stimulation techniques for managing sleep bruxism (SB) have recently emerged; however, the effect of the successive application of vibratory feedback stimulation has not been clarified. This study aimed to elucidate the effect of vibration feedback stimulation via an oral appliance (OA) on SB. Materials and methods: This prospective, single-arm, open -label intervention study included 20 participants diagnosed with "definite" SB who wore a specially designed OA for 98 nights at home. A force-based SB detection system triggered a vibrator attached to the OA. Vibratory stimulation was withheld during the first 3-week adaptation period (weeks 1 - 3), applied during the 9-week stimulation period (weeks 4 - 12), and withheld again during the post stimulation period (weeks 13 - 14). The number and duration of SB events per hour of sleep were calculated based on piezoelectric signals recorded with the OA-based vibration feedback device and compared between weeks 3 and 4, 8, 12, and 14 and between weeks 12 and 14 using the Friedman test (post -hoc test with Bonferroni correction). Results: The duration of SB events significantly decreased after vibratory stimulation (weeks 3 versus 4, 8, and 12: P < 0.001, P = 0.026, and P = 0.033, respectively) and then significantly increased upon cessation of vibratory stimulation after the stimulation period (weeks 12 versus 14: P < 0.001). Conclusion: Contingent vibratory stimulation through an OA-based vibration feedback device may suppress SB-related masticatory muscle activity continuously for 9 weeks and may be an effective alternative for managing SB. (c) 2024 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).