Do oral conditions influence the incidence of bloodstream infection after hematopoietic stem cell transplantation? A retrospective study in Japan.

PURPOSE: This study aimed to evaluate the incidence of bloodstream infection (BSI) among patients undergoing hematopoietic stem cell transplantation (HSCT) for teeth indicated for extraction. METHODS: Patients who underwent HSCT at Toranomon Hospital (Tokyo, Japan) between January 2017 and December 2019 were retrospectively evaluated. The incidence of BSI among patients with teeth indicated for extraction who did not undergo extraction (oral high-risk group) and patients who did not have this risk (oral low-risk group) was compared. RESULTS: Among the 191 consecutive patients included in this study, 119 patients were classified as undergoing high-risk transplantation. BSI after HSCT was observed in 32 out of 60 (53.3%) patients and 56 out of 131 (42.7%) patients in the oral low-risk and oral high-risk groups, respectively (p = 0.173). Multivariable analyses revealed that the presence of > 3 teeth as intraoral sources of infection and age over 50 years were determinants of BSI originating from the oral cavity after engraftment (odds ratio [OR], 9.11; 95% confidential interval [CI] 2.27-36.61]; p = 0.002; OR, 3.22; CI [1.47-7.08], p = 0.004, respectively). CONCLUSION: In patients undergoing HSCT, the presence of less than three intraoral sources of infection did not affect the incidence of BSI after HSCT.

Clinical application of robots in dentistry: A scoping review.

PURPOSE: The surge in digitalization and artificial intelligence has led to the wide application of robots in various fields, but their application in dentistry started relatively late. This scoping review aimed to comprehensively explore and map the current status of the clinical application of robots in dentistry. STUDY SELECTION: An iterative approach was used to gather as much evidence as possible from four online databases, including PubMed, the China National Knowledge Infrastructure, the Japan Science and Technology Information Aggregator, Electronic, and the Institute of Electrical and Electronics Engineers, from January 1980 to December 2022. RESULTS: A total of 113 eligible articles were selected from the search results, and it was found that most of the robots were developed and applied in the United States (n = 56; 50%). Robots were clinically applied in oral and maxillofacial surgery, oral implantology, prosthodontics, orthodontics, endodontics, and oral medicine. The development of robots in oral and maxillofacial surgery and oral implantology is relatively fast and comprehensive. About 51% (n = 58) of the systems had reached clinical application, while 49% (n = 55) were at the pre-clinical stage. Most of these are hard robots (90%; n = 103), and their invention and development were mainly focused on university research groups with long research periods and diverse components. CONCLUSIONS: There are still limitations and gaps between research and application in dental robots. While robotics is threatening to replace clinical decision-making, combining it with dentistry to gain maximum benefit remains a challenge for the future.

Anti-Inflammatory Therapy for Temporomandibular Joint Osteoarthritis Using mRNA Medicine Encoding Interleukin-1 Receptor Antagonist.

Messenger RNA (mRNA) is an emerging drug modality for protein replacement therapy. As mRNA efficiently provides protein expression in post-mitotic cells without the risk of insertional mutagenesis, direct delivery of mRNA can be applied, not only as an alternative to gene therapy, but also for various common diseases such as osteoarthritis (OA). In this study, using an mRNA-encoding interleukin-1 receptor antagonist (IL-1Ra), we attempted anti-inflammatory therapy in a rat model of the temporomandibular joint (TMJ) OA, which causes long-lasting joint pain with chronic inflammation. For the intra-articular injection of mRNA, a polyplex nanomicelle, our original polymer-based carrier, was used to offer the advantage of excellent tissue penetration with few immunogenic responses. While the protein expression was transient, a single administration of IL-1Ra mRNA provided sustained pain relief and an inhibitory effect on OA progression for 4 weeks. The mRNA-loaded nanomicelles provided the encoded protein diffusely in the disc and articular cartilage without upregulation of the expression levels of the pro-inflammatory cytokines IL-6 and tumor necrosis factor-α (TNF-α). This proof-of-concept study demonstrates how anti-inflammatory proteins delivered by mRNA delivery using a polyplex nanomicelle could act to alleviate OA, stimulating the development of mRNA therapeutics.

Does oral dryness influence pressure pain sensitivity in the oral mucosa of removable denture wearers?

OBJECTIVE: This study aimed to determine if oral dryness is associated with oral pain sensitivity in removable denture wearers. MATERIALS AND METHODS: The pressure pain threshold (PPT) in the mucosa at the midline between the central incisors in the maxilla and mandible was evaluated in 333 removable denture wearers (mean age 71.2 years, male 33.3%). The frequency of oral dryness and severity of anxiety were evaluated using self-reported questionnaires. Multilevel analyses considering the correlated data structure (jaws nested within individual) adjusted for age, sex, number of missing teeth, anxiety level, smoking status, and systemic diseases were performed to examine the association between PPT and oral dryness. Further subgroup analysis stratified by number of missing teeth was performed. RESULTS: Oral dryness was present in 122 (21.6%) of 566 jaws in 73 (21.9%) of the 333 subjects. The mean (standard deviation) of the log PPT was 2.00 (0.26) in the subjects who perceived oral dryness and 2.04 (0.22) in those who did not. Oral dryness was associated with a lower log PPT, but the relationship was not significant (coefficient - 0.017; 95% confidence interval - 0.071, 0.038). Subjects with oral dryness and edentulous oral mucosa had a significantly lower PPT (coefficient - 0.145; 95% confidence interval - 0.283, - 0.006) than their partially dentate counterparts. CONCLUSION: There was a significant association of oral dryness with increased pressure pain sensitivity in the oral mucosa only in jaws with complete dentures. CLINICAL RELEVANCE: The approach to oral dryness could contribute to reduction of oral pain sensitivity.

Clinical application of removable partial dentures using thermoplastic resin. Part II: Material properties and clinical features of non-metal clasp dentures.

This position paper reviews physical and mechanical properties of thermoplastic resin used for non-metal clasp dentures, and describes feature of each thermoplastic resin in clinical application of non-metal clasp dentures and complications based on clinical experience of expert panels. Since products of thermoplastic resin have great variability in physical and mechanical properties, clinicians should utilize them with careful consideration of the specific properties of each product. In general, thermoplastic resin has lower color-stability and higher risk for fracture than polymethyl methacrylate. Additionally, the surface of thermoplastic resin becomes roughened more easily than polymethyl methacrylate. Studies related to material properties of thermoplastic resin, treatment efficacy and follow-up are insufficient to provide definitive conclusions at this time. Therefore, this position paper should be revised based on future studies and a clinical guideline should be provided.

Effect of implant support for prostheses on electromyographic activity of masseter muscle and jaw movement in patients after mandibular fibula free flap reconstruction.

PURPOSE: Dental implants are used to stabilize, support, and retain prostheses in the mandible following fibula free flap reconstruction. A previous longitudinal prospective study showed that an implant-supported prosthesis (IP) provided additional improvement in masticatory performance compared to a conventional prosthesis (CP). Therefore, in this paper, the impact of implant retention and support of mandibular prostheses on neuromuscular function is reported via a within-subject analysis. MATERIALS AND METHODS: Forty-six participants were enrolled in the study. Prosthetic treatment with a CP was completed in 33 subjects following oromandibular resection and fibula free flap reconstruction. Twenty-five subjects completed evaluation of the CP after an adaptation period. Standardized masticatory tests with peanuts were given to subjects on the defect and nondefect chewing sides. Electromyography (EMG) of masseter muscles and jaw movement was performed and recorded simultaneously in 19 of these subjects. IP treatment was then completed in 16 of these subjects, and 15 of them participated in the IP evaluation after an adaptation period. Of these 15 subjects, 13 completed EMG and jaw movement recordings for both CP and IP. RESULTS: EMG activity of the defect-side masseter muscle increased significantly from CP to IP conditions when chewing on either side, but no significant change was found for nondefect-side muscle activity. Jaw movement parameters showed no significant changes from CP to IP. CONCLUSION: In patients restored with mandibular fibula free flap reconstruction, implant support for mandibular prostheses has the benefit of permitting greater muscle effort on the defect side, irrespective of the side on which the bolus is being chewed. The impact of an IP on jaw movements is limited.

Masticatory and swallowing threshold performances with conventional and implant-supported prostheses after mandibular fibula free-flap reconstruction.

STATEMENT OF PROBLEM: Significant strides in microvascular surgical techniques allow predictable restoration of bony and soft tissue orofacial defects. In combination with prosthetic rehabilitation, varying degrees of improvement in esthetics, speech intelligibility, and swallowing have been noted; however, the relative impact of conventional and implant-supported prostheses on restoration of masticatory function are not known. PURPOSE: The purpose of this study was to determine whether conventional or implant-supported dental prostheses and current surgical reconstructive procedures restore patients' masticatory function to presurgical levels. MATERIAL AND METHODS: Of the 46 subjects enrolled in this study, 23 (7 edentulous and 16 partially dentate) completed conventional prosthesis (CP) treatment and masticatory evaluation, and of these, 15 (3 edentulous and 12 partially dentate) completed treatment and evaluation with an implant-supported prosthesis (IP). Standardized masticatory performance tests with peanuts and carrots as the test food were made on the defect and nondefect sides. Tests of swallowing threshold performance were made with carrots as the test food. Statistical analysis included repeated-measures analysis of variance (ANOVA) with post hoc Tukey HSD tests (alpha=.05). RESULTS: Masticatory function at entry was markedly compromised. Further performance declines were noted following surgery (PS) on both the defect and nondefect sides. Restoration with CP and IP produced improvements (significant for defect side only, P<.05) in performance over the PS interval and were not significantly different from performances at entry prior to surgery. In addition, the performance on the defect side with the IP was significantly greater than the performance with the CP (P<.001). CONCLUSION: Impairment in masticatory ability remains following free-flap reconstruction prior to prosthetic rehabilitation. Both CP and IP may provide improved masticatory ability, permitting patients to regain the functional level they possessed prior to surgical intervention. The IP may contribute to greater support and stability of the prosthesis, resulting in increased use for mastication and superior performance on the defect side compared to the CP.