Journal of oral science最新文献

Purpose: To evaluate the flexural properties of repaired poly(methylmethacrylate) (PMMA) denture base materials for computer-aided design/computer-aided manufacturing (CAD-CAM) and to compare them with heat-activated polymerized PMMA.

Methods: A total of 288 specimens (65 × 10 × 2.5 mm) were prepared using both CAD-CAM and conventional blocks and repaired using autopolymerizing and visible-light polymerizing (VLC) materials. Microwave energy, water storage and hydroflask polymerization were applied as additional post-polymerization cycles after the repair process. The flexural strength (FS) of the specimens was evaluated using the three-point bending test. Data were evaluated statistically using 2-way ANOVA followed by Bonferroni's correction to determine the significance of differences between the groups (P ≤ 0.05).

Results: The FS of the denture base materials for CAD-CAM was significantly higher than that for the heat-activated group (P ≤ 0.05). The FS was significantly highest when microwave energy was used for the post-polymerization cycle. The FS values for all groups repaired with VLC resin were significantly lower than for the autopolymerization group (P ≤ 0.05).

Conclusion: The flexural properties of denture base materials for CAD-CAM repaired using autopolymerizing acrylic resins can recover by 50-70%. Additional post-polymerization cycles for autopolymerizing repair resin can be suggested to improve the clinical service properties of repaired dentures.

Purpose: To evaluate the biological and physical properties of calcium hydroxide-containing pulp-capping materials and their modifications with different solutions and antioxidant Resveratrol (RES) addition.

Methods: Calcium hydroxide+distilled-water:C, calcium hydroxide+saline:S, calcium hydroxide+synthetic tissue fluid:STF, Dycal:D, calcium hydroxide+distilled-water+RES:C+RES, calcium hydroxide+saline+RES:S+RES, calcium hydroxide+synthetic tissue fluid+RES:STF+RES, Dycal+RES:D+RES were tested. Cytotoxicity was determined by WST-1. Antibacterial-activity was evaluated by agar-diffusion. The water-absorption and solubility were examined for ISO-6876 and ISO-3107. The color-change was evaluated by spectrophotometer. Radiopacity was evaluated for ISO-6876 and ISO-9917. The normal distribution and homogeneity were determined and comparisons were made with appropriate analysis and post hoc tests (P < 0.05).

Results: The highest cell-viability was determined in the C+RES and the lowest was in D and D+RES after 24 h (P < 0.0001). RES-addition increased cell-viability and the highest rate was detected in C+RES, S+RES and STF+RES after 48 h (P < 0.0001). A limited inhibition-zone against Streptococcus mutans was detected in D and D+RES. RES-addition did not change the water-absorption in S and STF or the solubility in S group.

Conclusion: RES-addition may be used to increase the biocompatibility of calcium hydroxide without any adverse effect on physical properties. Saline may be the first choice as a mixing solution.

Purpose: The process of infection by bacteria and viruses involves invasion, establishment, growth, and parasitization. Poor oral hygiene and dysbiosis are significant risk factors for pneumonia. The aim of this study was to evaluate bacterial transport into the trachea during intubation for orthopedic surgery and the impact of oral hygiene treatment.

Methods: The study cohort included 53 patients with fracture who underwent surgical procedures under general anesthesia and were divided into two groups: an oral hygiene treatment (OHT) group (n = 27) and a control group (n = 26). Before intubation, the OHT group underwent preoperative oral hygiene treatment. Microbiological culture was used for detection and counting of bacteria from the oropharynx, trachea, and tip of the endotracheal tube (ETT).

Results: Patients in the OHT group had a lower pathogen detection rate and lower degree of bacterial colonization in the oropharynx, trachea, and ETT tip.

Conclusion: Preoperative oral hygiene treatment is able to reduce bacterial transport and colonization during orthopedic surgery, thus providing an important adjunct to pre-anesthesia care.

Purpose: Alveolar osteitis (dry sockets) is a painful condition characterized by a limited immune response. It is typically caused by the removal of blood clots from extracted tooth sockets, which leads to the fermentation of trapped food remnants by oral bacteria in the cavities, producing high concentrations of short-chain fatty acids (SCFAs). This study examined the effects of SCFAs on immunity and bone metabolism.

Methods: Mouse macrophage Raw264.7 cells were treated with oral bacteria supernatants or SCFA mixtures, and inducible nitric oxide synthase (iNOS) levels were determined by western blot. The same cells were treated with SCFA mixtures in the presence of receptor activator of nuclear factor-kappa B ligand (RANKL), and osteoclast-like cells were counted. MC3T3-E1 cells were treated with SCFA mixtures and stained with alizarin red S.

Results: Raw264.7 cells treated with oral bacterial culture supernatants of Porphyromonas gingivalis and Fusobacterium nucleatum inhibited lipopolysaccharide (LPS)-induced iNOS production, likely due to SCFA content. SCFA mixtures mimicking these supernatants inhibited the number of RANKL-induced tartrate-resistant acid phosphatase (TRAP)-positive cells and MC3T3-E1 cell mineralization.

Conclusion: These data suggest that SCFAs produced by P. gingivalis and F. nucleatum may reduce the inflammatory response and mildly induce mineralization of the alveolar walls. These results may contribute to the understanding of alveolar osteitis.

Purpose: This study examined the association between oral health and nutritional status among older patients receiving home-visit dental care.

Methods: This study enrolled 110 older patients (age ≥65 years) requiring long-term care who received home-visit dental care. The oral health indicators evaluated included number of teeth, occlusal support, number of functional teeth, tongue pressure, tongue coating index (TCI), and rinsing ability. Nutritional indicators included skeletal muscle mass index (SMI) and the mini-nutritional assessment short-form (MNA-SF). A multivariate modified Poisson regression analysis (adjusted for age, sex, medical history, care level, and housing type) was used to calculate prevalence ratios and 95% confidence intervals (CIs).

Results: The prevalence ratio for low SMI was not significantly higher for patients with ≥20 teeth than for those with 1-19 or no teeth. Number of teeth was not significantly associated with MNA-SF score. A high TCI score (2.15, 95% CI: 1.07-4.32) and poor rinsing ability (2.32, 95% CI: 1.25-4.30) were significantly associated with low SMI. High TCI scores were associated with low scores in MNA-SF categories (1.25, 95% CI: 1.01-1.55).

Conclusion: TCI and rinsing ability, rather than number of teeth, were associated with nutritional status in older patients requiring long-term care.

Purpose: This study investigated the color stability of different commercially available silicone materials for facial prostheses upon exposure to everyday beverages. It was hypothesized that the beverages would not alter the color of the silicone under conditions simulating daily exposure.

Methods: Sixty specimens were fabricated using two materials – VST-50 and Silfy – and exposed to commercially available cold mineral water, tea, or coffee. Specimen color was evaluated on days 1 and 15. The color was measured with a spectrophotometer based on CIELab system and color differences were calculated as ΔE. Statistical analysis was performed using the Kruskal-Wallis test and Mann-Whitney U test.

Results: The mean ΔE values after 15 days of exposure to mineral water, cold green tea, and coffee were 1.016, 3.480, and 3.636 for VST-50 and 0.440, 0.798, and 1.425 for Silfy, respectively. Both materials showed significant differences in color, and VST-50 showed a greater color change than Silfy, especially for coffee.

Conclusion: Pigmented silicone elastomers have low color stability, leading to an overall color change in silicone prostheses when exposed to pigmented beverages. Color changes in such prostheses can be mitigated by selecting materials with better color stability to extend their longevity.

Purpose: The effect of scan range and the number of scanned images on the precision of in vivo intermaxillary relationship reproduction was evaluated using digital scans acquired with an intraoral scanner.

Methods: The study involved 15 participants with normal occlusion. Two different interocclusal recording settings were employed using the intraoral scanner (TRIOS 4): 'MIN,' focusing on the minimal scan range of the first molar region, and 'MAX,' including the scan range from the right first premolar to the right second molar. These settings were combined with three different image counts, resulting in six experimental conditions. Interocclusal recordings were performed four times for each condition. Dimensional discrepancies between datasets were analyzed using three-dimensional morphometric software and compared using two-way analysis of variance.

Results: Median dimensional discrepancies (interquartile range; IQR) of 39.2 (30.7-49.4), 42.2 (32.6-49.3), 30.3 (26.8-44.1), 20.1 (16.0-34.8), 21.8 (19.0-25.1), and 26.6 (19.9-34.5) µm were found for MIN/200, MIN/400, MIN/600, MAX/200, MAX/400, and MAX/600, respectively. Significant differences in dimensional discrepancies according to scan range were found. Wilcoxon signed-rank test showed significant differences between MAX and MIN (P < 0.01).

Conclusion: Scan range may affect the precision of intermaxillary relationship reproduction. Thus, scanning of the most extensive region practically achievable is recommended.

Purpose: To investigate the elemental composition, corrosion resistance, and mechanical properties of computer-aided design and computer-aided manufacturing (CAD-CAM) retainers versus conventional fixed retainers (FRs).

Methods: Eight different retainer wires were investigated. Energy dispersive X-ray spectroscopy was used to determine the elemental composition. Leakage was analysed according to ISO 10271:2020 guidelines. Hardness was tested using the Vickers method with a load of 0.3 kg. The tensile force and tensile strength were evaluated. Multiple comparisons among wires of hardness, tensile force, and strength were conducted using the Welch t-test, with Bonferroni correction.

Results: Nickel was present in all wires. The CAD-CAM-FR wire, which contained more nickel than the other wires, had no measurable leakage. The gold-plated wires had the highest total leakage, but did not exceed the ISO standard limit. The hardness of the stainless-steel twisted wires was the highest and that of the CAD-CAM-FR wire was the lowest. The tensile strength of the CAD-CAM-FR wire was significantly lower than that of the other wires and similar to the other twisted-wire retainers.

Conclusion: The CAD-CAM-FR wire is likely to have high corrosion resistance and flexibility due to its low hardness.

Characterization of the metal component of dental restorations and fixed prostheses is useful for the treatment of dental metal allergies and personal identification. This study aimed to describe the composition of metal elements in dental restorations and fixed prostheses in the oral cavity of 43 cadavers of Japanese adults aged 55 years or older in forensic autopsies conducted at a university. In this study, Ag-Pd-Au alloys were most frequently detected, and the percentage of Ni alloys was smaller than that reported in patients with dental metal allergies. Furthermore, alloys containing other elements, such as Fe or Hg, were also detected in some cases.

Customized posts-and-cores have been widely used for improved fitness within a prepared post space. However, in comparison to direct restoration, they necessitate an increased number of appointments for patients. A 24-year-old man presented with a maxillary left canine that had fractured due to trauma 10 months previously. For this case, a digital process was used for simultaneous restoration with a personalized titanium post-and-core and a zirconia crown achieved with an intraoral scanner (IOS) and computer-aided design/computer-aided manufacturing (CAD-CAM). This workflow allowed the restoration to be completed in 2 visits, facilitating more effective and predictable treatment, with reduced time and cost for the patient.