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The concept of oral frailty was first proposed in Japan in 2014 by the "Joint Working Committee on Oral Frailty," consisting of three academic societies-the Japan Geriatrics Society, the Japanese Society of Gerodontology, and the Japanese Association on Sarcopenia and Frailty-to enhance public understanding of oral frailty. Oral frailty is a state between robust oral function (a "healthy mouth") and its decline, characterized by slight declines in oral function, including tooth loss and difficulties in eating and communicating, which increase the risk of impaired oral functional capacity but can be reversed with proper intervention and treatment. Oral frailty can be assessed using the Oral Frailty 5-item Checklist (OF-5) without the need for a dental health professional. Oral frailty is defined as having at least two of the following components: (i) fewer teeth, (ii) difficulty chewing, (iii) difficulty swallowing, (iv) dry mouth, and (v) low articulatory oral motor skills. Approximately 40% of community-dwelling older adults have oral frailty. Oral frailty is associated with poor dietary variety, social isolation, physical frailty, disability, and mortality. This statement introduces the concept and definition of oral frailty, a new assessment tool (OF-5), and concept diagrams for healthcare professionals and the general public. These tools aim to promote public awareness and facilitate collaboration between medical and dental healthcare providers. Geriatr Gerontol Int 2024; 24: 1111-1119., (© 2024 The Author(s). Geriatrics & Gerontology International published by John Wiley & Sons Australia, Ltd on behalf of Japan Geriatrics Society.)

Background: Treating oral problems with dentist intervention during hospitalisation may improve patients' food intake status., Objectives: This study aimed to clarify whether convalescent rehabilitation ward inpatients in a hospital with hospital dentistry (HHD) had a better diet at discharge than those in a hospital without hospital dentistry (HNHD)., Methods: Retrospective observational study including inpatients with dental involvement in a HHD with dentists and dental hygienists and HNHD with dental hygienist and visiting dental service between 1 March and 31 August 2022. Data included age, sex, body mass index (BMI), Functional Independent Measure (FIM) motor and cognitive, Oral Health Assessment Tool (OHAT) score, Food Intake LEVEL Scale (FILS), whether the FILS ≥8 (indicating that patient eats also a non-texture-modified diet), remained and functional tooth numbers and speech language hearing therapist (SLHT) and dentist interventions. Comparisons between the two hospitals and factors that affected the FILS ≥8 were examined., Results: A total of 333 and 89 inpatients were included in the HHD and HNHD groups, respectively. After propensity score matching, the HHD group had a significantly higher rate of FILS ≥8, functional tooth numbers at discharge, and SLHT and dentist intervention rates. The multivariable logistic regression analysis for propensity score matching participants showed that the significant independent variables for FILS ≥8 were age, BMI, FILS, FIM motor (all at admission) and SLHT and dentist interventions. Odds ratio for dentist intervention was 14.46 (95% CI: 4.36-48.01)., Conclusions: Dentists are necessary to improve patients' food intake status in convalescent rehabilitation wards., (© 2024 John Wiley & Sons Ltd.)

Statement of Problem: Studies on the movement of artificial teeth during the manufacturing of computer-aided design and computer-aided manufacturing (CAD-CAM) complete dentures using the custom disk method with milled recesses and on whether the movement is within a clinically acceptable range are lacking., Purpose: The purpose of this in vitro study was to assess the trueness and precision of the artificial teeth on custom disks the recesses of which were manufactured using a milling machine and to compare the results with the recesses manufactured using a 3-dimensional (3D) printer., Material and Methods: Four types of artificial teeth (maxillary left central incisors [Max-L1], mandibular left central incisors [Man-L1], maxillary left first premolars [Max-L4], and maxillary left first molars [Max-L6]) were prepared. Milling data were created, and 3 of each type of tooth were attached to each disk made up of 3 concentric circles (large, medium, and small). Five each of the 3D printed custom disks and custom disks with milled recesses were milled based on the milling data. Standard tessellation language data were obtained through cone beam computed tomography and superimposed by using a CAD software program. Mean absolute error (MAE) values were calculated to assess trueness and precision; MAE values of artificial teeth in custom disks with milled recesses and 3D printed custom disks were statistically compared by using the 2-way analysis of variance test with 2 factors, 2 types of custom disks and 4 types of artificial teeth, and the Tukey post hoc comparison (α=.05)., Results: Regarding position trueness, the MAE value of Man-L1 on the milling custom disk was significantly lower than that of the 3D printed custom disk (P<.001), whereas the MAE values of Max-L4 and Max-L6 on the milling custom disk were significantly higher than those on the 3D printed custom disk (P<.001). No significant difference was found in the MAE value of the position trueness of Max-L1 between the milling and 3D printed custom disks. Regarding position precision, the MAE values of Max-L1, Man-L1, and Max-L4 on the milling custom disk were significantly lower than those on the 3D printed custom disks (P=.002, P<.001, P=.025, respectively). However, no significant difference was seen in the MAE value of position precision of Max-L6 between the milling and 3D printed custom disks (P=.180) CONCLUSIONS: Movement of artificial teeth during the manufacture of dentures using the custom disk method and custom disks with milled recesses was within a clinically acceptable range., (Copyright © 2022 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Background: Differences in the effects of cream-type denture adhesives and home liners remain unclear., Objective: This cross-sectional study aimed to clarify the differences in the oral-hygiene status and masticatory performance between participants using cream-type denture adhesives and those using home liners., Methods: Masticatory performance with and without cream-type denture adhesives and home liners was evaluated using colour-changeable chewing gum. Oral hygiene was assessed using the tongue coating index (TCI). Propensity-score matching was performed using oral moisture, presence of palatal or mandibular protuberances, type of residual ridge, denture type (complete or partial denture), and denture retention as background factors. Wilcoxon signed-rank test was used to examine the differences in masticatory performance with and without cream-type denture adhesives and home liners and differences in masticatory performance and TCI between the cream-type denture adhesive and home-liner groups., Results: This study included 38 and 40 cream-type adhesive and home-liner users, respectively, and 17 pairs were obtained after propensity-score matching. The Wilcoxon signed-rank tests showed that masticatory performance was significantly different with and without the use of home liners, and higher values were obtained with the use of home-liners. However, the cream-type denture adhesive and home-liner groups showed no significant differences in terms of the change in masticatory performance with the use of them. Furthermore, Wilcoxon signed-rank tests showed that TCI values were significantly high in the cream-type adhesive group., Conclusion: The findings in this study suggest that home liners improve masticatory performance and that participants regularly using cream-type denture adhesives have poorer oral hygiene., (© 2024 John Wiley & Sons Ltd.)

Purpose: Color-changeable chewing gums are used to evaluate masticatory performance, as measured by a colorimeter or visually based on a color scale. Although anyone can use a color scale, the evaluation accuracy depends on the evaluator. We develop an application that can determine the degree of color change in chewing gum using smartphone images, making color evaluation accurate and easy to measure., Methods: For the application, 60 chewed gum samples were prepared. Two shots were captured using two smartphone models. To create the application algorithm, a formula was developed to approximately map the color value from the smartphone images to the true value using a colorimeter. A basic validation was performed on 60 new samples covering a range of colors, followed by a field validation on 100 healthy dentate participants aged 20-39 years., Results: The intraclass correlation coefficient for two repeated shots had a high value ≥ 0.97 in the basic and field validations, confirming reliability. No significant differences were observed in the paired t-test and Wilcoxon signed-rank test, and a significant and strong correlation (correlation coefficient ≥ 0.92) was observed between the evaluation values using the colorimeter and the basic and field validations. Bland-Altman plots further confirmed the validity of the application., Conclusions: A software application was developed to enable easy, quick, and accurate determination of the masticatory performance of a chewing gum from images taken using a smartphone with highly reliable and validated results.

Purpose: This in vitro study investigated the effect of build orientation on the wear resistance and hardness of denture teeth fabricated using digital light processing (DLP) compared to other denture tooth materials., Methods: Disc-shaped specimens were prepared using denture tooth monomers and DLP devices in three build orientations: 0°, 45°, and 90°. Specimens of the same shape were fabricated using denture tooth materials for subtractive manufacturing, commercially available polymethylmethacrylate (PMMA) resin, and composite resin. The wear resistance was evaluated as the wear volume loss after 50,000 wear cycles using a ball-on-disc wear device in water for two-body wear and poppy seed slurry for three-body wear. The Vickers hardness values of the materials were measured. Two-way and one-way analyses of variance were performed for wear resistance and hardness, respectively, followed by Tukey's honest significance test., Results: The interaction between the denture tooth resins and maximum wear volume was significant (P < 0.01). The 0° build orientation exhibited the lowest wear volume in the three-body wear test and the highest hardness among the three build orientations. The 0° DLP-fabricated specimens demonstrated significantly less wear volume than that of the PMMA specimens and a wear volume comparable to that of the milled specimens. However, the 0° DLP-fabricated specimens showed significantly lower hardness than that of the milled and PMMA specimens. The composite resin specimens exhibited the highest wear resistance and hardness., Conclusions: A 0° build orientation is recommended for DLP-fabricated denture teeth compared to 45° and 90° orientations to achieve greater wear resistance and hardness.

Background: The association between oral food intake and oral function during the subacute stage of stroke is not well known., Objective: To investigate (1) oral function changes in subacute stroke patients and (2) association between oral function and oral intake status at several time points., Methods: In a prospective study involving 324 stroke patients at a convalescent rehabilitation unit, four oral function parameters (maximum tongue pressure, MTP; lip-tongue motor function, LTMF; maximum occlusal force, MOF and oral health assessment tool, OHAT) were quantitatively measured upon admission (T0), at 1 month (T1) and 2 months (T2). Oral feeding status was assessed using the Functional Oral Intake Scale (FOIS) and divided based on the FOIS score into the dysphagic and regular diet groups. The changes in oral functions at the three time points were tested using generalized estimating equation analysis. The association between FOIS groups and oral functions at T1 and T2 was analysed by means of logistic regression analysis., Results: All oral function parameters improved significantly over time during the hospital stay (mean differences: 4.9 for MTP, 0.6 for LTMF, 1.1 for MOF and -1.8 for OHAT). The FOIS groups were significantly associated with MTP (p < .05) and OHAT (p < .05) at both T1 and T2., Conclusion: Our findings suggest that oral function significantly improves in patients during subacute stroke rehabilitation and better oral health can be associated with better oral intake. Improved oral function through dental intervention and oral rehabilitation may contribute to gains in oral food intake., (© 2024 John Wiley & Sons Ltd.)

Highly polished 3, 4, and 5 mol% yttria-stabilized zirconia and CAD/CAM composite resin samples were prepared, and the influence of surface roughness (R a and S a , 21 areas/group), wettability (contact angle and surface energy, 3 samples/group), and surface chemical composition (2 samples/group) on single-strain bacterial adhesion models (Porphyromonas gingivalis, Streptococcus oralis, Streptococcus sanguinis, Streptococcus gordonii, and Streptococcus mutans) were compared via fluorescent staining with graphical analysis (21 areas/group). Statistical analysis was performed using the Shapiro-Wilk test followed by one-way analysis of variance with Tukey's test or the Kruskal-Wallis test with Dunn's test (α=0.05) and linear regression. For dental zirconia with the same surface roughness, the yttria content did not significantly influence the initial bacterial adhesion. However, higher bacterial adhesion was detected for the composite resin owing to its high C, O, and Si contents. There was no correlation between surface energy and bacterial adhesion for any bacterial strain (p<0.005).

Background/purpose: Appropriate oral health assessment and management can improve the oral health and nutritional status of hospitalized patients. The active participation of dental professionals in the nutritional support team (NST) can help achieve this outcome. However, the participation of dental professionals in NSTs is often limited, indicating the requirement for establishing a remote oral health assessment method. This study aimed to establish a multidisciplinary oral health assessment system using short video recordings with a tablet device., Materials and Methods: Fifty inpatients receiving NST aid at the Tokyo Medical and Dental University Hospital were included in this study. The degree of agreement between the oral health assessment performed at the bedside and using the short video recordings of the oral health acquired with a tablet device by a single dentist and the degree of agreement for evaluations performed using the video recordings between multiple professionals were evaluated. The oral health status was assessed using the Oral Health Assessment Tool (OHAT)., Results: The intraclass correlation coefficient (ICC) of the OHAT total scores for oral health assessment performed at the bedside and using the videos by a single dentist was 0.914 (95% confidence interval [CI], 0.854-0.950). ICCs of the OHAT total scores for the video assessment performed by dentists and multiple professionals were 0.904 (95% CI, 0.838-0.944) and 0.802 (95% CI, 0.676-0.883), respectively., Conclusion: Comprehensive oral health assessment of patients can be performed by multiple professionals using the short video recordings of the oral health acquired with a tablet device., Competing Interests: The authors have no conflicts of interest relevant to this article. The funders had no role in designing the study; the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results., (© 2024 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Introduction: Oral hypofunction comprises seven aspects of oral condition, including oral hygiene, oral dryness, bite strength, tongue-lip motor function, tongue pressure, masticatory function, and swallowing function. Each of these seven has a single diagnostic criterion; however, the use of a single indicator without consideration of sex, age, or other factors is controversial. The purpose of this study was to evaluate the association between the oral hypofunction test and sex, age, and number of remaining teeth., Methods: The study was conducted at 12 facilities by the members of the Japanese Society of Geriatric Dentistry during April to December 2019. The participants comprised 181 healthy older adults aged 65 years and over (56.9% female; age range 65-95 years) who regularly visited these facilities. All tests of oral function and oral status available in Japan were performed on the participants, and the association between these tests and sex, age, and number of remaining teeth was examined., Results: Sex differences were observed in masticatory function, bite force, lip closure force, jaw-opening force, oral diadochokinesis "ka," and tongue coating index (p < .05). In men, age was weakly (r = 0.20-0.40) associated with masticatory function, jaw-opening force, maximum tongue pressure, oral diadochokinesis, and swallowing function. In women, the number of remaining teeth, masticatory function, jaw-opening force, and oral diadochokinesis "ta" and "ka" was also weakly associated with age., Conclusions: Performance on the oral hypofunction test differs by sex, age, and number of remaining teeth. This means that the current single criterion for evaluation requires caution in its interpretation., (© 2024 Gerodontology Association and John Wiley & Sons Ltd.)

Objective: As the participation of dental professionals in multidisciplinary care is often limited, instructions on oral health management provided by dental professionals to other professionals are important to achieve transdisciplinary oral health management; however, the effectiveness of such instructions remains unclear. In this longitudinal study, we aimed to determine the impact of oral health management provided by dental professionals and nurses instructed on oral health management by dental professionals on the oral health of inpatients eligible for a Nurition Support Team (NST)., Methods: The study participants were 117 patients (66 men and 51 women, mean age: 71.9 ± 12.5 years) who received oral health management during the NST intervention period. The participants received oral health management from nurses (Ns group) or dental professionals (D group). The nurses who conducted the oral health management received instructions from dental professionals. Oral health was assessed at the beginning and end of the NST intervention using the Oral Health Assessment Tool (OHAT)., Result: The Ns and D groups showed significant improvements in the total OHAT scores at the end of the NST intervention. Both groups showed significant improvements in the OHAT subitems of lip, tongue, gums and tissues, saliva, oral cleanliness and dental pain, while only the D group showed a significant improvement in the denture subitem., Conclusion: Effective oral health management provided by dental professionals or by nurses trained by them improved the oral health status of inpatients eligible for NST at an acute-care hospital., (© 2024 John Wiley & Sons Ltd.)

We examined the effect of consuming Hoshinishiki, a type of high-amylose rice, on postprandial glucose as measured by continuous glucose monitoring in diabetes patients. A single-blinded clinical trial involving 11 hospitalized patients diagnosed with type 1 or type 2 diabetes was performed. The patients consumed high-amylose rice for 2 days (days 2 and 4 of the study) and control rice for 2 days (days 1 and 3 of the study). Linear mixed models were used to test the effects on the 24-h mean glucose levels, time in range (TIR), incremental area under the curve of glucose levels at 2 h after meals, the average glucose levels at 1, 2, and 3 h after meals, and the maximum glucose levels within 3 h. The results showed that the consumption of high-amylose rice led to significantly lower 24-h mean glucose levels, levels at 2 and 3 h after a meal, and postprandial glucose peak levels within 3 h, as well as significantly higher TIR. A similar trend was observed when the analysis was restricted to patients with type 2 diabetes. These results suggest that high-amylose rice may be a more beneficial staple food for glycemic control than regular rice., Competing Interests: No potential conflicts of interest were disclosed., (Copyright © 2024 JCBN.)

Background/purpose: Impaired masticatory performance results in nutritional deficiencies in older adults. This systematic review aims to investigate the following clinical question (CQ): Do occlusal supports impact nutritional intake or nutritional status in older individuals?, Materials and Methods: An extensive systematic literature search was performed to summarize the currently available knowledge to address the CQ. The cohort and intervention studies with participants of ≧60 years old or a mean age of 65 years performed before May 2021 were included. Studies were required to measure the parameters related to occluding tooth pairs/occlusal units and food/nutrient intake and/or nutritional status. Bias risk was assessed using the Risk of Bias Assessment Tool for Nonrandomized Studies., Results: After an independent screening of 1130 initial records, 24 reports from 22 studies were included. Participants (n = 8684) in the included studies were mainly residents of nursing homes or community-dwelling individuals. Following the assessment of bias risk, it is revealed that all studies had methodological weaknesses. Over half of the studies concluded that there was an association between occlusal support and nutritional intake or status. However, it was also revealed that various confounding factors are involved in the association between occlusal support and nutrition., Conclusion: This systematic review concludes that occlusal support might be associated with nutritional intake or nutritional status in the older population, although there are methodological limitations of each study. The evidence is still insufficient, and more well-designed studies are required., Competing Interests: None., (© 2023 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Background/purpose: Gum chewing has been found to improve oral function. Nevertheless, few randomized controlled trials have investigated the effects of gum-chewing exercises on oral function in older adults. This study aimed to examine the effect of gum-chewing exercises on oral function in older adults., Materials and Methods: This was a single-blind, randomized controlled trial, conducted from November 2021 to January 2022. A total of 130 participants were divided randomly into the intervention and control groups. The intervention group was told to chew experimental gums for one month, while the control group was instructed to chew experimental tablets for one month. Maximum bite force, occlusal contact areas, oral dryness, tongue pressure, tongue and lip functions (number of times each of the following syllables is pronounced per second:/pa/,/ta/, and/ka/), masticatory function, subjective masticatory function, and gum-chewing time were measured at baseline and one month following intervention to assess outcomes., Results: One month following the intervention, tongue pressure was significantly higher in the intervention group than in the control group ( P  = 0.027). In the within-group comparisons, maximum bite force ( P  < 0.001), unstimulated saliva flow ( P  < 0.001), tongue and lip functions (/pa/: P  < 0.001;/ta/: P  < 0.001;/ka/: P  < 0.001), color scale value ( P  = 0.019), and ΔE value ( P  = 0.024) were significantly increased in the intervention group., Conclusion: The results suggest that gum-chewing exercises can improve oral functions in older adults, although additional increases in masticatory load may be necessary to establish a more effective oral function training method using gum-chewing exercises in older adults., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2023 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Aim: This cross-sectional study had two aims: to assess the prevalence of oral frailty (OF), according to the Oral Frailty 5-Item Checklist (OF-5), among community-dwelling older adults; and to examine the associations among oral frailty, dietary variety, social engagement, and physical frailty., Methods: We pooled data from two population-based studies (the Otassha Study and the Itabashi Longitudinal Study on Aging). With the OF-5, OF is characterized by the presence of two or more of the following: (i) fewer teeth, (ii) difficulty in chewing, (iii) difficulty in swallowing, (iv) dry mouth, and (v) low articulatory oral motor skills. We calculated the OF prevalence for each sex. We assessed dietary variety, social engagement, and physical frailty. Generalized structural equation modeling was employed to investigate the associations among oral frailty, low dietary variety (dietary variety score ≤3), social isolation (Lubben Social Network Scale score <12), and physical frailty (Japanese version of the Cardiovascular Health Study score ≥3)., Results: A total of 1206 individuals (626 women and 580 men) with a mean age of 74.7 years were included. The prevalence of OF was 36.7%, and it increased with age; however, there was no significant sex difference. OF was significantly indirectly associated with physical frailty via low dietary variety (odds ratio, 1.43; 95% confidence interval, 1.04-1.97) and social isolation (odds ratio, 1.42; 95% confidence interval, 1.04-1.94)., Conclusions: Two of five community-dwelling older adults exhibited OF. Low dietary variety and social isolation are potential underlying mechanisms through which OF is indirectly associated with physical frailty. Geriatr Gerontol Int 2024; 24: 371-377., (© 2024 Japan Geriatrics Society.)

In this study, we investigated the effects of surface treatment on the fracture strength of porcelain-veneered zirconia. Highly translucent 4 mol% yttria-stabilized zirconia disks (KATANA HT, Kuraray Noritake Dental) were divided into three surface-treatment groups: 1)as-sintered, 2) alumina sandblasted, and 3) ground. Crystallographic and surface-roughness analyses were conducted for each group. Veneering ceramics (Cerabien ZR, Kuraray Noritake Dental) were applied to the zirconia surfaces. The fracture strengths of the porcelain-veneered zirconia disks were measured using biaxial flexural-strength tests. Crystallographic analysis revealed that grinding and sandblasting increased the fractions of the monoclinic and rhombohedral zirconia phases. The ground specimens had a higher surface roughness than the sandblasted specimens. Weibull analysis showed no significant differences in biaxial flexural strength among the three groups. The results suggest that these surface treatments do not affect the fracture strength of porcelain-veneered zirconia.

This study aimed to clarify the effects of multiple firings on the translucency, crystal structure, and mechanical strength of highly translucent zirconia. Four types of highly translucent zirconia (LAVA Esthetic, LAVA Plus, KATANA Zirconia STML, and KATANA Zirconia HTML) were fired three times at three different temperatures, and the translucency, crystal structure, and flexural strength were evaluated before and after firing. The translucency was statistically compared using repeated-measures analysis of variance; the zirconia phase composition was assessed using X-ray diffraction followed by Rietveld analysis; and the biaxial flexural strength was assessed using Weibull analysis. The translucency of LAVA Esthetic and KATANA Zirconia HTML decreased significantly after firing, and the crystal composition of LAVA Plus and KATANA Zirconia HTML changed after multiple firings, whereas multiple firings did not affect the biaxial flexural strength of any samples. Thus, multiple firings may affect the optical properties of highly translucent zirconia.

Statement of Problem: The custom disk is a novel method of complete denture fabrication; however, patient-reported outcomes and fabrication costs are unknown., Purpose: The purpose of this retrospective study was to evaluate general patient satisfaction with complete dentures fabricated through the custom disk method. In addition, a comparative cost-effectiveness analysis was conducted for the custom disk method and conventional removable complete dentures., Material and Methods: Complete dentures were fabricated for 44 edentulous participants by using the custom disk method (n=20) or the conventional removable complete denture (n=24). General patient satisfaction was measured by using visual analog scales before and after denture fabrication and compared by using the Wilcoxon signed-rank test (α=.05); the fabrication cost for each method was investigated and compared by using the Mann-Whitney U test (α=.05). Cost-effectiveness was analyzed with the incremental cost-effectiveness ratio as incremental cost per change in general patient satisfaction for the custom disk method with respect to the conventional removable complete denture., Results: The median general patient satisfaction with the custom disk method and conventional removable complete denture after the intervention was 84.0 mm and 91.0 mm, respectively. General patient satisfaction with the custom disk method was significantly higher after the intervention (P=.002). The median labor costs for the custom disk method and conventional removable complete denture were 24 516 and 36 583 Japanese yen, respectively, and the difference was statistically significant (P<.001). The median of the total cost of the custom disk method and the conventional removable complete denture was 41 104 and 45 276 Japanese yen, respectively, and the difference was statistically significant (P=.004). The incremental cost-effectiveness ratio was -251.4., Conclusions: The custom disk method improved general patient satisfaction. The labor and total costs of the custom disk method were significantly lower than those of the conventional removable complete denture. The incremental cost-effectiveness ratio demonstrated that the custom disk method was more cost-effective than the conventional removable complete denture., (Copyright © 2022 Editorial Council for The Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Purpose Additive manufacturing has revolutionized the fabrication of complete dentures. However, this process involves support structure, which is a construction part that holds the specimen during printing, and may prove to be disadvantageous. Therefore, this in vitro study compared the effect of support structure reduction on various volume and area distributions of a 3D-printed denture base to determine optimal parameters based on accuracy.Methods A complete maxillary denture base construction file was used as reference. Twenty denture bases were 3D printed under four conditions (total n=80): no support structure reduction (control), palatal support structure reduction (Condition P), border support structure reduction (Condition B), and palatal and border support structure reduction (Condition PB). Printing time and resin consumption were also recorded. The intaglio surface trueness and precision of all acquired data were exported to a 3D analysis software, and the dimensional changes to the denture base were analyzed using the root-mean-square estimate (RMSE) to assess geometric accuracy and generate color map patterns. Nonparametric Kruskal-Wallis and Steel-Dwass tests (α=0.05) analyzed the accumulated data.Results Control had the lowest RMSE values for trueness and precision. Nevertheless, it demonstrated a significantly lower RMSE than that of Condition B (P=0.02) in precision. Owing to negative deviation at the palatal region, Conditions P and PB had higher retention than Control and Condition B regarding the color map pattern.Conclusions Within the limitations of this study, the reduction of palatal and border support structures showed optimal accuracy with resource and cost savings.

Purpose This technical procedure report explains the fabrication protocol for a newly developed 4D-printed sports mouthguard (MG) based on 4D-printing technology.Methods An intraoral scanner was used to scan a maxillary arch model. A two-layer sports MG was designed based on the scanned model using computer-aided design software and output in a standard tessellation language file format. Two types of filament materials were used for the MG material: a thermoplastic shape memory polyurethane elastomer with a unique glass transition temperature for the external layer and a thermoplastic elastomer for the internal layer. Both MGs were printed using a fused deposition modeling 3D printer and assembled using adhesives after trimming the support material. To confirm the shape-memory performance of the fabricated 4D-printed MG, a deviation analysis was performed by superimposing the internal surface data of the fabricated MG and the MG whose shape was recovered. The distance between the data obtained by deviation analysis was calculated, and the root mean square error value (mm) was determined.Conclusions The 4D-printing technology simplifies the complex processes required with conventional methods. It also overcomes the issues of conventional and 3D-printed MGs, such as the reduced fitting accuracy caused by deformation, because this technology employs shape memory materials.

Purpose: The purpose of this study is to investigate the effects of denture adhesives on masticatory performance via a 10-center, parallel, randomized, controlled trial of complete denture wearers in Japan., Methods: The trial was conducted between September 2013 and October 2016. The inclusion criteria were complete edentulism, willingness to undergo new complete denture treatment, and willingness to return for recall treatment. The exclusion criteria were age 90 years or older, presence of severe systemic illness, inability to understand the questionnaires, wearing metal base complete dentures, denture adhesive user, wearing prosthetics for maxillofacial defects, wearing complete dentures with tissue conditioners, and severe xerostomia. Randomization of the powder-type denture adhesive (powder), cream-type denture adhesive (cream), and control (saline) groups was performed using a sealed envelope system. Masticatory performance was measured using color-changeable chewing gum. Intervention blinding was not feasible., Results: Sixty-seven control, 69 powder, and 64 cream participants are analyzed using the intention-to-treat principle. The participants in all groups show significantly improved masticatory performance at post-intervention (paired t-test with Bonferroni correction P < 0.0001). However, no significant difference in masticatory performance is detected among the three groups (one-way analysis of variance). A significant negative correlation between pre- and post-changes in masticatory performance and intraoral condition scores is observed (Pearson's correlation coefficient, P < 0.0001)., Conclusions: Although denture adhesives improved the masticatory performance of complete denture wearers, their clinical effects are comparable to those of saline solution. The use of denture adhesives is more effective in complete denture wearers with unsatisfactory intraoral conditions.

Objectives: To investigate factors influencing postoperative bleeding occurrence after dental extraction in older patients receiving anticoagulation therapy., Materials and Methods: This retrospective study included patients aged ≥ 65 years receiving one of the following anticoagulants: apixaban, edoxaban, rivaroxaban, and warfarin. Patients who underwent one to multiple tooth extractions in the geriatric dentistry clinic at Tokyo Medical and Dental University Hospital between August 1, 2016, and November 30, 2020, were included. The outcome variable was postoperative bleeding occurrence. Logistic regression analysis was performed with the following ten factors as explanatory variables: age, sex, maximum systolic blood pressure during the extraction, type of local anesthesia, vertical incision, osteotomy, usage of surgical splints, the mesiodistal width of the extracted tooth on a radiograph, use of antiplatelet agents, and history of diabetes requiring medication., Results: Among 395 participants (mean age, 82.3 ± 6.5 years) included in this study, 75 patients experienced postoperative bleeding after tooth extraction. Logistic regression analysis revealed that the odds ratios for the vertical incision (18.400, p < 0.001), osteotomy (3.630, p = 0.00558), usage of surgical splints (1.860, p = 0.0395), and the mesiodistal width of the extracted tooth on a radiograph (1.060, p = 0.0261) were statistically significant., Conclusions: For dental extraction in older patients receiving anticoagulants, postoperative bleeding is more likely to occur in patients with vertical incision, osteotomy, and posterior or multiple tooth extractions., Clinical Relevance: Dentists should consider suturing and adjunctive hemostatic procedures for patients undergoing vertical incision, osteotomy, and multiple tooth extractions while receiving anticoagulation therapy to minimize the risk of postoperative bleeding., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Statement of Problem: The effect of using the custom disk method (CDM) for fabricating digital dentures on patients' masticatory function should be studied to support its use in clinical practice., Purpose: To investigate the effect of digital dentures fabricated using CDM on patients' masticatory function., Material and Methods: This single-center prospective clinical study included 20 patients with edentulous maxillary and mandibular arches who used a complete denture. The digital impression and complete denture manufacturing procedures using CDM have already been reported by Kanazawa et al. (2018) [32] and Soeda et al. (2022) [18] Thedigital dentures fabricated with CDM were delivered to the participants, and periodic adjustments were made until the patient could use the denture without pain. A color-changeable chewing gum, two types of gummy jellies that can evaluate the masticatory function, and pressure-sensitive sheets were used to evaluate the participants' masticatory function at baseline, 1 month, and 6 months following adjustment of the new digital complete dentures fabricated with CDM. These masticatory function values had already been measured in the previous conventional dentures and were recorded as baseline values., Results: The study participants included 8 women and 12 men (mean age, 77.6 years). The color-changeable chewing gum analysis indicated that there was no significant improvement of masticatory function from baseline to 1 M (P = .083) and 6 M (P = .157).The gummy jelly analysis indicated no significant differences between the masticatory function baseline and 1 month (P = .387); however, a significant improvement was observed from baseline to 6 months (P = .020). Tests with Glucolum indicated a significant improvement from baseline to 1 month (P = .012) and 6 months (P = .003). The maximum bite force and occlusal contact area showed no significant difference at any time point., Conclusions: Significant improvement in masticatory function was observed upon evaluation with gummy jelly and Glucolum 6 months after delivering the new digital complete dentures. Under limited conditions, the digital denture fabricated using CDM resulted in good recovery of the masticatory function in elderly edentulous patients. The present results combined with the cost-effectiveness and patient satisfaction associated with CDM indicate its clinical utility., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Maiko Iwaki reports financial support was provided by JSPS, Japan; 10.13039/501100001691Japan Society for the Promotion of Science. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

The older adult population in Japan is expected to increase. Therefore, long-term care and frailty prevention are important. However, the relationship between masticatory performance, nutritional intake, and frailty remains unclear. This cross-sectional study aimed to examine energy, protein, and vitamin D intake and its association with frailty and masticatory performance in older adults. Patients between January 2022 and January 2023 were recruited and divided into robust and frail groups. Masticatory performance, nutrition, frailty, and other data, such as age and sex, were evaluated through onsite measurements and a questionnaire. Logistic regression analysis was conducted with frailty as a dependent variable and masticatory performance as an independent variable, adjusting for age, sex, skeletal muscle mass, living alone, energy intake, protein-energy ratio, and vitamin D intake. No significant differences were observed between the groups regarding age or sex. The robust group showed significantly better results for protein-energy ratio, vitamin D intake, and subjective and objective masticatory performance than the frail group. Logistic regression analysis revealed a significant correlation between skeletal muscle mass, protein-energy ratio, and objective masticatory performance with frailty. Masticatory performance was associated with frailty, independent of the intake of nutrients such as energy, protein, and vitamin D.

Purpose: This study aimed to predict the positional coordinates of incisor points from the scan data of conventional complete dentures and verify their accuracy., Materials and Methods: The standard triangulated language (STL) data of the scanned 100 pairs of complete upper and lower dentures were imported into the computer-aided design software from which the position coordinates of the points corresponding to each landmark of the jaw were obtained. The x, y, and z coordinates of the incisor point (X P , Y P , and Z P ) were obtained from the maxillary and mandibular landmark coordinates using regression or calculation formulas, and the accuracy was verified to determine the deviation between the measured and predicted coordinate values. Y P was obtained in two ways using the hamular-incisive-papilla plane (HIP) and facial measurements. Multiple regression analysis was used to predict Z P . The root mean squared error (RMSE) values were used to verify the accuracy of the X P and Y P . The RMSE value was obtained after cross-validation using the remaining 30 cases of denture STL data to verify the accuracy of Z P ., Results: The RMSE was 2.22 for predicting X P . When predicting Y P , the RMSE of the method using the HIP plane and facial measurements was 3.18 and 0.73, respectively. Cross-validation revealed the RMSE to be 1.53., Conclusion: Y P and Z P could be predicted from anatomical landmarks of the maxillary and mandibular edentulous jaw, suggesting that Y P could be predicted with better accuracy with the addition of the position of the lower border of the upper lip., (© 2023 The Korean Academy of Prosthodontics.)

Zirconia restorations are increasingly popular in dental treatment. Yttria-stabilized zirconia (YSZ) needs to be sintered for clinical applications and novel speed-sintering protocols are being developed for chairside treatments. Whether the properties of speed-sintered YSZ meet clinical requirements, however, remains unclear. Therefore, we conducted a systematic review and meta-analysis on the influence of speed-sintering on the optical and mechanical properties of dental YSZ according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. A literature search was conducted using PubMed, Embase, and Web of Science databases for relevant articles published between January 1, 2010 and February 28, 2022 in English, Chinese, or Japanese. After full-text evaluation and quality assessment, 26 articles were selected. Meta-analysis revealed that speed-sintering does not significantly affect the CIEDE2000-based translucency parameter, contrast ratio, three-point flexural strength, biaxial flexural strength, or fracture toughness of YSZ ( p  < 0.01) compared to conventional sintering. However, the CIELab-based translucency parameter of conventionally sintered YSZ is higher than that of speed-sintered YSZ. The descriptive analysis indicated that speed-sintering does not affect the hardness of YSZ compared to that of conventionally sintered YSZ. The results indicate that speed-sintering is suitable for preparing YSZ for dental restorations., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Background: Oral health management involving dental professionals in a multidisciplinary Nutritional Support Team (NST) is effective collaborative care. However, the indicators for the triage of oral health management requirements and selection of oral healthcare providers remain unclear., Objective: This cross-sectional study included inpatients with malnutrition and aimed to investigate the factors associated with determining the need for oral health management involving dental professionals and selecting primary oral healthcare providers when needed., Methods: Participants included 255 inpatients (154 males and 101 females, mean age 69.7 ± 14.4 years) aged ≥20 years who underwent oral assessment by the NST between April 2016 and July 2019. Participants were assigned to the following groups: good oral health group, oral health management by nurses under the supervision of dental professionals group, and oral health management by dental professionals group. The comprehensive oral health status was investigated using the Oral Health Assessment Tool (OHAT). The total OHAT score ranges from 0 to 16, with a higher score indicating a poorer oral environment., Results: The total OHAT score had a significant correlation with the need for oral health management by dental professionals. Inpatients with denture problems required oral health management from dental professionals. The optimal cutoff value of the total OHAT score for determining the need for oral health management was four., Conclusion: The need for oral health management by dental professionals increased with worsening oral health status, especially denture problems. The OHAT score could be used to triage inpatients who require oral health management collaborated with dental professionals., (© 2023 John Wiley & Sons Ltd.)

Traditionally, simulation studies in dentistry have relied on the finite element method (FEM). However, the smoothed particle hydrodynamics (SPH) method, which represents objects as particle collections without the use of meshes, has gained recent attention. Despite its application in dentistry, there is currently a lack of comprehensive literature summarizing the specific applications of the SPH method in the oral region. This review aims to provide a summary of studies that have utilized the SPH method in dentistry, focusing on its applications in analyzing large deformations, such as dental ceramic collisions, soft material analysis (e.g., denture adhesive), and virtual training simulations for dental treatments. By combining the advantages of the SPH and FEM methods, more accurate simulations can be achieved, and further applications of the SPH method in dentistry are anticipated.

No specific methods have been officially proposed for the prevention and improvement of oral hypofunction. Therefore, in this randomized controlled trial, we aimed to develop a gum-chewing training program and determine its effects in older adults. A total of 218 older adults, aged 65-85 years, were randomly allocated to the intervention or control groups. The intervention group chewed the experimental gum daily, whereas the control group consumed the experimental granular food daily. The outcome assessments measured the maximum bite force, occlusal contact areas, oral dryness, tongue pressure, tongue and lip functions, masticatory function, and gum-chewing time. The measured values for each outcome were compared between groups using the Mann-Whitney U test and within groups pre- and post-intervention using the Wilcoxon signed-rank test. A total of 211 participants completed the study. After 2 months, the intervention group had a significantly higher maximum bite force than the control group ( p = 0.01), indicating that gum-chewing training improved maximum bite force in older adults. This was determined using one type of bite force measuring device. Therefore, it is suggested that gum-chewing training has a high potential to improve oral hypofunction.

Purpose: This study aimed to determine the effects of denture adhesives on denture retention and occlusal force in complete denture wearers in a multicenter, randomized, parallel-group controlled trial., Methods: Two hundred edentulous patients wearing complete dentures were allocated to three groups: powder-type denture adhesive, cream-type denture adhesive, and control (saline solution). Denture adhesives and saline solution were applied to the dentures for 4 days. The retentive force of the dentures and occlusal force were measured using a force transducer occlusal force meter at baseline and after 4 days of intervention. In addition to between-group comparisons, subgroup analyses of denture retention and occlusal force were performed based on the level of difficulty of the edentulism treatment. The levels were ranked as I (easy), II, III, and IV (difficult)., Results: Cream-type denture adhesives significantly improved the retentive force of the dentures (P<0.01) and occlusal force (P<0.05), with no significant differences between baseline and post-intervention forces in the powder-type denture adhesive and control groups. In within-group comparisons, cream-type denture adhesives improved both the retentive and occlusal forces at Level II (P<0.05), and powder-type denture adhesives improved the occlusal force at Level II (P<0.01)., Conclusions: Application of cream-type denture adhesives effectively improves the denture retention and occlusal force in complete denture wearers with a moderate degree of difficulty during edentulism treatment.

Purpose: Although digital removable partial dentures have been previously described, there have been no reports on how to fabricate them in one piece. This study proposes a new method for fabricating patient-specific digital removable partial dentures using a custom plate., Methods: First, a gypsum model was scanned using a laboratory scanner and a removable partial denture was designed using computer-aided design (CAD) software based on standard tessellation language data. The metal clasp was fabricated from Ti-6Al-4V using a 3D printer. For custom plate fabrication, a resin plate frame was designed using computer-aided design (CAD) software and fabricated using a 3D printer. An artificial tooth and metal clasp were fixed on the base surface of the frame, an auto-polymerizing resin was poured into the frame for the denture base, and the artificial tooth and metal clasp were packed to form a custom plate. The plate was cut using a milling machine. Subsequently, the support attached to the denture was removed and polished for complete fabrication of the denture., Conclusions: Our novel removable partial denture fabrication method is more efficient than the conventional method. The obtained removable partial dentures demonstrated satisfactory accuracy.

Purpose: We evaluated the effects of build orientation and bar addition between lingual flanges on the accuracy of mandibular denture bases fabricated using a digital light processing (DLP) device., Methods: Mandibular denture bases with and without a bar at the lingual flanges were virtually designed and assigned to eight build orientations. Six dentures per condition were fabricated using a DLP device with a methacrylate-based photopolymerizable monomer (Dima Print denture base) (n=96). The fabricated denture surfaces were digitized, and intaglio surfaces were obtained. These digitized surfaces were compared via superimposition using graphical software (Artec studio12 profession) to their original designed files, and root mean square estimates were obtained. The trueness of the entire and intaglio data was statistically analyzed non-parametrically., Results: The range of trueness of the entire and intaglio denture bases was 0.15-0.31 mm and 0.11-0.38 mm, respectively. The trueness at 135° and 270° for the entire denture base and that at 270° for the intaglio data without the bar were significantly lower than those for the other build orientations. The trueness at 270° was <0.15 mm irrespective of the conditions. The trueness with the bar of all build orientations, except that of 0° for intaglio data, was significantly smaller than or equal to the trueness without the bar of the corresponding build orientations., Conclusions: Build orientation and bar addition influenced the accuracy of the complete dentures fabricated using DLP. A build orientation of 270° is recommended for fabricating a mandibular complete denture, irrespective of the bar addition.

Background: Coordination between the trunk and head is considered important for walking stability. Recent studies have reported that wearing complete dentures could improve trunk stability during walking; however, its effect on the head has not been clarified., Objective: This study aimed to clarify the effect of complete dentures on head stability during walking in edentulous older adults., Methods: Twenty edentulous older adults (11 men and 9 women; mean age, 78.6 ± 5.8 years) who used complete dentures were included in the study. Acceleration and angle rate sensors were placed on the participants' brow, chin and waist, and they were asked to walk a 20-m passage under two conditions: with and without dentures. The outcomes used to assess head stability were the variance values of acceleration and angle rate, the peak-to-peak values, harmonic ratio, root mean square, integrated values of the difference and dynamic time warping data obtained from the sensors. The variance values of the brow acceleration were compared using a paired t-test, and other outcomes were compared using a Wilcoxon signed-rank test. All significance levels were set at 5%., Results: In acceleration without dentures, the variance values of the chin and the peak-to-peak values of the brow and chin were significantly larger than with dentures. Angle rate without dentures, the variance values and the peak-to-peak values of the brow and chin were also significantly larger than with dentures., Conclusion: Wearing complete dentures while walking might improve head stability and contribute to walking stability in edentulous older adults., (© 2023 John Wiley & Sons Ltd.)

Aim: To enable easy assessment of oral frailty; that is, an overlapping slight decline in multifaceted oral function, in any setting, we developed the oral frailty five-item checklist (OF-5), and examined its predictive validity for increased risks of physical frailty, physical disability and mortality among community-dwelling older adults., Methods: This population-based cohort study randomly selected 2044 residents in Kashiwa, Japan, with no long-term care needs. Baseline data were collected in 2012, and follow-up data were collected in 2013, 2014, 2016, 2018 and 2021. The OF-5 includes five measures: fewer teeth, difficulty in chewing, difficulty in swallowing, dry mouth and low articulatory oral motor skills. Physical frailty was defined according to the Cardiovascular Health Study criteria. Physical disability and mortality determined from the long-term care insurance receipt database were followed for 9 years., Results: Of 2031 eligible participants (mean age 73.1 ± 5.6 years; 51.1% women), 39.3% individuals with ≥2 OF-5 points had significantly increased prevalence and new-onset rate of physical frailty. After adjusting for potential confounders, oral frailty, defined as ≥2 OF-5 points, was associated with increased risks of physical disability (adjusted hazard ratio 1.40; 95% confidence interval 1.14-1.72) and mortality (adjusted hazard ratio 1.44; 95% confidence interval 1.11-1.87). The highest adjusted hazard ratios were observed in older adults with coexisting physical and oral frailty., Conclusions: The OF-5 showed strong predictive validity for physical frailty, physical disability and mortality in Japanese older adults. This assessment tool can be implemented in various settings and foster comprehensive prevention through interprofessional collaboration. Geriatr Gerontol Int 2023; 23: 651-659., (© 2023 The Authors. Geriatrics & Gerontology International published by John Wiley & Sons Australia, Ltd on behalf of Japan Geriatrics Society.)

Objective: To investigate the occurrence of mild cognitive impairment in edentulous patients up to 3 years after they received single-implant overdentures (1-IODs)., Methods: This was a follow-up study for a crossover randomized controlled trial comparing 1-IODs and conventional complete dentures, with patient satisfaction as the primary outcome. In the present study, the cognitive function of the patients, measured with the Japanese version of the Montreal cognitive assessment (MoCA-J), was evaluated as the secondary outcome at baseline and 2 months, 1 year, 2 years, and 3 years after 1-IOD placement. The total and domain (memory, executive function, visuospatial skills, language, attention, and orientation) MoCA-J scores of the patients at each timepoint were analyzed and compared., Results: Twenty-two patients with edentulous mandibles received 1-IODs. Within-group comparisons revealed that the total MoCA-J scores at 1 year and 3 years after 1-IOD placement were significantly increased compared with baseline scores. Additionally, the memory domain scores at all timepoint were significantly increased compared with the baseline scores, and the executive function domain scores at the 2-month, 2-year and 3-year timepoint were significantly increased compared with the baseline scores., Conclusion: Patients with edentulous mandibles who underwent 1-IOD placement showed significantly improved total scores of MoCA-J after 1 year and 3 years of wearing 1-IODs. In addition, they showed significantly improved memory domain scores at 2 months, 1 year, 2 years, and 3 years after 1-IOD placement and executive function domain scores at 2 months, 2 years, and 3 years after 1-IOD placement., Clinical Significance: The results of this study suggest that 1-IOD treatment for older adults, especially those with edentulous mandibles, may prevent cognitive decline regardless of the condition of the maxilla., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: We investigated and compared the stress distribution within one- and two-piece mini-implants for overdentures with three different attachments (ball, Locator, and magnet) and two different diameters using three-dimensional finite element (3D FE) analysis and a monotonic bending test. The goal was to identify the most beneficial implant attachment system design for mini-implant overdentures with a lower risk of implant fracture., Methods: Twelve 3D FE models simulating a mandible segment with one- and two-piece mini-implants with different attachment systems, diameters, and overdentures were created using three-dimensional computer-aided design (CAD) software. Vertical and oblique forces (45° to the longitudinal axis of the implant) of 100 N were applied to the dentures. The stress distribution was analyzed. A bending test was performed on a mini-implant (Locator, 2.4 mm) using a testing machine to quantify the load at yield stress., Results: One-piece mini-implants showed lower maximum stress compared to two-piece mini-implants. Among the three designs, the magnet attachment systems showed the maximum stress. The maximum von Mises stress occurred at the neck of the implants, which was surrounded by cortical bone in all models, and under both loading conditions., Conclusions: Focusing on the attachments and one- and two-piece designs of mini-implant overdentures using CAD models to reduce confounding factors affecting the stress distribution, we concluded that one-piece mini-implants tended to show lower stress compared to two-piece mini-implants. Mini-implant overdentures with Locator and ball attachments demonstrated lower stress within the implants compared to those with magnet attachments under vertical and oblique loading conditions.

Purpose: Maintaining good masticatory function from a young age promotes lifelong health, yet limited studies have explored masticatory performance in young individuals. We investigated the relationship of sex, age, and individual oral functions with masticatory performance among junior and senior high school students and young adults., Methods: This cross-sectional study included students aged 12-13, 14-15, and 16-17 years (groups S1, S2, and S3, respectively) and young adults aged 20-40 years (group YA). We assessed oral functions, the number of functional teeth, and anthropometric measurements. Masticatory performance was evaluated using color-changeable chewing gum. We analyzed sex-related differences in each group and age-related differences in each sex. Multiple linear regression analysis was performed using masticatory performance as the dependent variable to investigate related factors., Results: Among the 522 children and 100 young adults, males exhibited significantly higher masticatory performance than females in groups S1, S3, and YA. Among males, groups S2, S3, and YA exhibited significantly higher masticatory performance than group S1. Among females, group S2 exhibited higher masticatory performance than groups S1 and S3. Male sex, the maximum occlusal force and tongue pressure, and the number of functional teeth were significantly correlated with masticatory performance., Conclusions: Masticatory function development differed by sex, with males exhibiting higher masticatory performance than females. We identified that male sex, the maximum occlusal force and tongue pressure, and the number of functional teeth were significantly associated with masticatory performance. Our findings provide a basis for masticatory performance assessment in different age groups.

Mild cognitive impairment (MCI), including memory loss, has been attracting attention in Japan. This study assessed the effect of new complete dentures provision alone and with dietary intervention on cognitive functions assessed using the Japanese version of the Montreal Cognitive Assessment (MoCA-J). A randomized controlled trial was conducted with 70 older adults who required new complete dentures. The participants had new complete dentures fabricated and were randomly classified into the intervention or control group. The intervention group received simple dietary advice, and the control group only received denture care advice. Cognitive function was assessed using the MoCA-J before and at 3 and 6 months after treatment. The between-group comparison and within-group comparison were analyzed. No significant differences were reported for comparisons between the intervention and control groups. A significant increase was revealed in the within-group comparisons for the total scores between the 3- and 6-month assessments ( p = 0.002) and between the baseline and 6-month assessments ( p = 0.012) in the intervention group. In the control group, a significant increase in the total scores was not revealed between any of evaluation period. Complete denture replacement combined with simple dietary intervention may help improve MoCA-J scores in edentulous older adults.

This 1-year multicenter prospective cohort study aimed to determine the association between observable eating and swallowing function factors and outcomes (death/hospitalization or survival) among elderly persons in long-term care insurance facilities in Japan. Baseline assessments of factors, such as language, drooling, halitosis, hypersalivation, tongue movement, perioral muscle function, coughing, respiration after swallowing, rinsing, and oral residue, among others, were conducted. A score of 0 was considered positive, and a score of 1 or 2 was considered negative. Patient age, sex, body mass index, Barthel index, and Clinical Dementia Rating were recorded. The death/hospitalization or survival rates over 1 year were recorded, and patients were allocated into groups depending on the respective outcome (death/hospitalization group or survival group) and baseline characteristics. A total of 986 residents from 32 facilities were included, with 216 in the death/hospitalization group and 770 in the survival group. Language, salivation, halitosis, perioral muscle, coughing, respiration after swallowing, rinsing, and oral residue were significantly associated with the outcomes ( p < 0.05). Therefore, routine performance of these simple assessments by caregivers may allow early detection and treatment to prevent death, pneumonia, aspiration, and malnutrition in elderly persons.

Objectives: To investigate crystallography, translucency, phase content, microstructure and flexural strength of two commercial strength-gradient multilayered dental zirconia grades., Methods: Two zirconia grades, i.e., KATANA Zirconia YML (Kuraray Noritake; referred to as "YML"; composed of four layers: enamel, body 1-3) and IPS e.max ZirCAD Prime (Ivoclar Vivadent; referred to as "Prime"; composed of three layers: enamel, transition, body) were investigated. Fully sintered square-shaped zirconia specimens from each layer were prepared. Microstructure, chemical composition, translucency parameter and zirconia-phase composition of each layer were characterized. Four-point and biaxial flexural strength of each layer was measured using fully sintered bar- and square-shaped specimens. Square-shaped samples were used to measure strength across the layers., Results: For both multilayer zirconia grades, the 'enamel' layer contains a higher amount of c-ZrO 2 , which resulted in higher translucency but lower flexural strength than the 'body' layers. The characteristic 4-point flexural strength of the YML 'body 2' (923 MPa) and 'body 3' (911 MPa) layers, and of the Prime 'body' (989 MPa) layer were comparable and higher than for the YML 'enamel' (634 MPa), Prime 'transition' (693 MPa) and 'enamel' (535 MPa) layers. The biaxial strength of specimens sectioned across the layers was in-between that of the 'enamel' and 'body' layers for both YML and Prime, implying the interfaces did not form a weak link., Significance: The difference in yttria content affects the phase composition and mechanical properties of each layer of the multi-layer zirconia. The strength-gradient approach allowed to integrate monoliths with irreconcilable properties., (Copyright © 2023 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.)

The environments of nursing home staff and residents have dramatically changed since the onset of the COVID-19 pandemic, with greater demand for infection control. This study aimed to clarify the changes and regional differences in the surrounding environment of nursing home residents as well as the working environment of staff, including oral health care, after the spread of SARS-CoV-2. A self-administered questionnaire survey was sent to nursing staff at about 40 nursing homes in different areas of Japan in September and October 2021. The questionnaire consisted of items centered around: (1) the surrounding environment of nursing home residents, (2) awareness and attitudes towards daily work among staff, and (3) attitudes to and procedures for oral health care among staff. A total of 929 respondents included 618 (66.5%) nursing care workers and 134 (14.4%) nurses. Regarding changes in resident daily life, 60% of staff perceived decreases in psychosocial and physical function after the start of the pandemic due to limited family communication and recreational activities, especially in urban areas. Concerning infection control, most respondents adopted routines of disinfecting hands before and after their duties. Oral health care was part of the regular duties of over 80% of respondents. Many participants answered that the frequency and time of oral health care only slightly changed after the onset of COVID-19, but many also reported disinfecting hands both before and after oral health care, particularly in rural areas. Our findings suggested that the COVID-19 pandemic decreased the daily living activities of residents, leading to psychosocial and physical decline, especially in urban areas. The results also indicated that the spread of SARS-CoV-2 triggered improvements in the awareness and attitudes towards infection control in daily work, including oral health care, among nursing care staff, notably in rural areas. Such an effect may contribute to a more positive perception of oral health care infection measures after the pandemic.

Although a surface pre-reacted glass ionomer (S-PRG) exerts a suppressive effect on Candida albicans (C. albicans) activity and growth, its influence on the expression of the lipase gene (LIP) family including LIP1-LIP10, an indicator of clinical infection, has not yet been investigated. Therefore, in this study, we evaluated the effect of S-PRG filler eluates on LIP expression in C. albicans using real-time reverse-transcription polymerase chain reaction. Candida albicans was treated with an S-PRG filler diluted at ratios of 1:32 and 1:64 for 24 h at 37°C. The diluted S-PRG filler eluates (1:32) suppressed lipase activity in C. albicans by downregulating LIP5 (0.54±0.25 relative to that of the control) and LIP8 (0.35±0.074) expression after 24 h, which corresponded with decreased lipase activity. At a dilution factor of 1:64, there was no significant difference in LIP expression. Thus, the S-PRG filler eluate has potential to suppress fungal activity by downregulating LIP expression.

The type of denture adhesive, cream or home-liner, chosen by regular denture adhesive users and oral conditions contributing to this selection require elucidation. The factors associated with denture adhesive selection were investigated through a face-to-face survey on oral and denture conditions. Age, sex, oral moisture, masticatory performance, retention and stability of the removable denture, ridge shape, mucosal thickness, and duration of denture use were examined in cream and home-liner-type denture adhesive users who did not regularly visit a dentist. Univariate analysis and multivariate analyses were performed. There were 38 and 40 cream-type and home-liner-type adhesive users, respectively. The type of denture adhesive was significantly associated with the oral moisture value, retention, ridge shape, mucosal thickness, and duration of denture use in univariate analyses. The residual ridge conditions with large factor loadings for ridge shape and mucosal thickness and duration of denture use were significantly related to the denture adhesive selection in multivariate logistic analysis. The residual ridge conditions and duration of denture use were significant factors in the selection of cream- and home-liner-type denture adhesives. These results can provide appropriate guidance based on the adhesives patients without dental supervision are more likely to choose., Competing Interests: The authors declare no conflicts of interest.

In this study, the cooling rate-dependent properties of polyphenylene sulfide (PPS) and carbon fiber reinforced PPS (CF/PPS) manufactured at different cooling rates (1, 5, and 10 °C/min) are presented. The cooling rate-dependent densities of neat PPS and CF/PPS were determined based on the Archimedes' principle. The coefficients of thermal expansion (CTEs) were determined using a thermomechanical analyzer. The stress-strain curves of neat PPS manufactured at different cooling rates under tensile, compressive, and shear loading were obtained using a universal tester. In addition, the R curves of CF/PPS and the corresponding load-displacement curves are presented under mode I and mode II loading. The experimental data provide useful information for the development of numerical models that depend on both cooling rates and stress triaxiality. In addition, the data can be directly utilized to evaluate the properties and quality of carbon fiber reinforced thermoplastic components in the aerospace, automobile, energy, and civil engineering industries. Detailed experimental results have been presented in a previous study [1]., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Author(s).)

Zirconia ceramics have been widely used in dentistry. Herein, we assess the surface morphology, surface texture, and osteoblast response of additively manufactured zirconia and alumina-toughened zirconia (ATZ) in comparison with titanium. The surface roughness, contact angle, and surface microstructure of titanium sandblasted with large-grit alumina and subsequently acid-etched using 18% HCl and 49% H 2 SO 4 (SLA-titanium), uniaxially pressed zirconia (UP zirconia), additively manufactured zirconia (AM zirconia), and additively manufactured ATZ (AM ATZ) were investigated. Moreover, the cell viability, alkaline phosphatase (ALP) activity, and gene expression of type I collagen on these materials were evaluated. The data were statistically analyzed using one-way ANOVA with Tukey's post hoc test. SLA-titanium showed the highest surface roughness and contact angle. The other three materials showed comparable surface roughness and contact angles. Micro- and nanoroughness were observed on the surface of SLA-titanium. UP zirconia and AM zirconia had similar surface morphologies. The cell viability, ALP activity, and gene expression of type I collagen on AM zirconia were comparable to or better than those on SLA-titanium. Our results indicate that AM zirconia is a promising material for zirconia dental implants.

Objectives: This prospective study aimed to compare the oral functions of removable partial dentures (RPDs) with those of implant-assisted removable partial dentures (IARPDs) with short implants and magnetic attachments in patients with mandibular Kennedy class I and II., Material and Methods: Thirty participants with mandibular Kennedy class I or II and at least three distal missing teeth were recruited. Oral functions, including mixing ability, comminuting ability, maximum bite force, and occlusal contact area, were assessed for RPDs (stage 0), IARPDs with healing caps (stage 1), and IARPDs with magnetic attachments (stage 2). The implants were loaded with occlusal force in stages 1 and 2. Finally, the data of the 27 participants who completed the evaluation at stage 2 were analyzed. The Wilcoxon signed-rank test with Bonferroni correction was used to assess the differences in the oral functions among the different stages., Results: The implant survival rate was 93.8%. There were significant differences in the comminuting ability and occlusal contact area between stages 0 and 2 (p < .001 and p = .036, respectively) and stages 1 and 2 (p = .003 and p = .015, respectively). Regarding the maximum bite force, there was a significant difference between stages 1 and 2 (p = .018). However, there was no significant difference in the mixing ability between the three stages., Conclusions: Within the limitations of this study, it was concluded that IARPDs in the mandible with short implants and magnetic attachments may improve oral functions., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

This systematic review provides an update on the development and efficacy of direct restorative dental materials for root caries interventions from in vitro and clinical studies. PubMed, Embase, and Web of Science were searched using specific MeSH keywords. Full articles from September 1990 to October 2021 were collected. Additional articles were identified by reference retrieval and manual searching. Studies not related to restorative materials for root caries treatment, case reports, non-original articles, and/or articles not written in English were excluded. Bias risk assessment was performed for the clinical studies. Forty-two articles (eleven clinical studies and thirty-one in vitro studies) were included for analysis. Most in vitro studies indicated an excellent cariostatic effect of glass ionomer cement. Resin-modified glass ionomer restorations also presented reduced recurrent caries activity but had a lower efficacy than glass ionomer cement restorations. For composite resin restorations, the main material development strategies are to strengthen the tooth structure and integrate antimicrobial activity. The clinical studies offered limited data, so the most appropriate material for surface root caries treatment is still inconclusive. However, atraumatic restorative treatment (ART) is an alternative treatment for patients with limiting conditions. Further clinical studies are required to confirm the efficacy of bioactive materials., (© 2021 The Authors.)