Journal of oral science最新文献

Purpose: To evaluate the marginal integrity of various pit and fissure sealants subjected to different application methods.

Methods: A total of 253 non-carious human third molars extracted and randomly divided into two groups according to the preparation method employed: invasive or non-invasive. Eight fissure sealant materials were tested: nano-filled flowable composite (Filtek Ultimate Flow), nanohybrid flowable composite (GrandioSo Flow), micro-hybrid flowable composite (Majesty Flow), resin-based unfilled fissure sealant (ClinPro Sealant), resin-based filled fissure sealant (Fissurit FX), resin-based highly filled fissure sealant (GrandioSeal), giomer-based fissure sealant (BeautiSealant), and glass ionomer-based fissure sealant (Fuji Triage). Samples were subjected to two-year cyclic thermo-mechanical and brushing simulations. Two observers quantitatively evaluated the restoration margins and classified them as either "permanent restoration edge", or if a gap larger than 250 μm was evident, "gapping at the restoration edge". The extent of the gap was recorded as a percentage relative to the total length of the restoration edge.

Results: The baseline marginal adaptation had no significant effect on the marginal adaptation (P > 0.05). However, the preparation method and type of fissure sealant material had a significant impact on the marginal adaptation (P < 0.05).

Conclusion: On the basis of quantitative analysis, the highest marginal integrity was observed for flowable composites, whereas the lowest was observed for glass ionomer-based fissure sealant.

Purpose: The aim of this study was to optimize the immunoresponsive and anti-Candida albicans (C. albicans) properties of guided bone regeneration-resorbable membranes (collagen) using additives based on synergistic mixtures of chlorhexidine with terpene-enriched fractions from Lippia alba essential oils (EO).

Methods: The anti-C. albicans activity of the fractions (individually or combined with chlorhexidine) was evaluated using planktonic and sessile cultures. J774A.1 murine macrophage cells were used to determine the cytotoxicity and immunoresponsive effects of the therapies.

Results: The anti-planktonic and anti-sessile performance of chlorhexidine on C. albicans was improved 2- to 4-fold by supplementation with citral-rich fractions. On macrophages, this fraction also exhibited a potentially cytoprotective action against the toxic effects of chlorhexidine, minimizing damage to the cell membrane, mitochondrial membrane potential, and nuclear integrity. Macrophages growing on collagen-membrane fragments and stimulated with the citral fraction (alone or with chlorhexidine) showed a significant increase in releasing the osteogenic cytokine TNF-α and enhancing the IL-4.

Conclusion: This combined therapy appears as a promising platform for the development of a prophylactic or therapeutic biocidal solution that can optimize the pharmacological characteristics of chlorhexidine (epithelium tolerance and anti-C. albicans consolidation on surfaces), as well as potentiating the immunoresponsive properties of collagen membranes.

Purpose: To compare the effects of gels containing 2.5% and 5% carboxymethyl chitosan amorphous calcium phosphate (CMC-ACP) on the microhardness of primary tooth enamel.

Methods: Twenty-four tooth specimens were demineralized with 37% phosphoric acid and divided into four groups: an untreated control group, a positive control group treated with casein phosphopeptide amorphous calcium phosphate, and two groups treated with 2.5% and 5% CMC-ACP gel, respectively. The enamel surface hardness was then measured with a Vickers hardness tester.

Results: In terms of Vickers Hardness Number (VHN), the degree of alteration in tooth surface microhardness was 77.83 ± 13.44 in the 5% CMC-ACP group and 52 ± 6.93 in the 2.5% CMC-ACP group (P = 0.002). The inter-group difference in the surface hardness change was significant (P < 0.05).

Conclusion: The 5% CMC-ACP gel increased the hardness of primary tooth enamel to a greater degree than the 2.5% CMC-ACP gel.

Purpose: This study examined the occlusion effect of a dentifrice containing stannous fluoride (SnF₂) and sodium fluoride (NaF) on periodontally involved teeth in comparison with healthy teeth using scanning electron microscopy (SEM) in comparison with a dentifrice containing NaF alone.

Methods: Sixty dentine samples obtained from single-rooted premolars, 15 of them extracted for orthodontic reasons (Group H) and 15 because of periodontal destruction (Group P), were included in the study. Each group of specimens was further divided into subgroups: HC and PC (control), H1 and P1 (treated with SnF₂ and NaF), and H2 and P2 (treated with NaF). The samples were brushed twice a day for 7 days, kept in artificial saliva, and examined by SEM. The diameters of open tubules and the numbers of tubules were assessed at ×2,000 magnification.

Results: The H and P groups showed similar diameters of open tubules. The numbers of open tubules in Groups H1, P1, H2, and P2 were significantly lower than in Groups HC and PC (P < 0.001), and consistent with the percentages of occluded tubules. Group P1 had the highest percentage of occluded tubules.

Conclusions: Although both dentifrices were found to successfully occlude dentinal tubules, the dentifrice containing SnF₂ and NaF provided the highest degree of occlusion in periodontally involved teeth.

Purpose: This study aimed at evaluating the effects of surface treatments with tetrabutylammonium dihydrogen trifluoride (TDTF) on the bond strengths of indirect resin composites with titanium-aluminum-vanadium (Ti-6Al-4V) and cobalt-chromium (Co-Cr) alloys.

Methods: Disk-shaped Ti-6Al-4V and Co-Cr alloy specimens were air-abraded with alumina, treated with an etchant (MEP) containing TDTF for 10 s (MEP10) or 30 s (MEP30), and rinsed with water. Subsequently, a primer containing 6-methacryloyloxyhexyl phosphonoacetate was applied to the surfaces, and the specimens were veneered with a light-curing indirect resin composite. Specimens without MEP were prepared as controls (no-MEP). Shear bond strengths were determined before or after 100,000 thermocycles, and the data were analyzed using the Steel-Dwass test (α = 0.05, n = 10).

Results: No significant difference was found in the bond strengths between the Ti-6Al-4V and Co-Cr alloys. In each metal alloy, the MEP10 and MEP30 specimens exhibited higher bond strengths than the no-MEP controls after 100,000 thermocycles. Scanning electron microscopy observations revealed that submicron-pits and crevices were formed on both the metal alloys upon applying the MEP etchant.

Conclusion: Surface treatments with TDTF following air abrasion are useful for improving bonding durability while veneering resin composites on Ti-6Al-4V or Co-Cr alloy frameworks.

Purpose: Medication-related osteonecrosis of the jaw (MRONJ) is characterized by necrosis of the jawbone with intraoral bacterial infection and has a significant negative impact on oral health-related quality of life. Risk factors for the onset are unknown, and definitive therapeutic approaches have not yet been defined. A case-control study at a single institution in Mishima City was conducted. The purpose of this study was to examine in detail the factors that contribute to the development of MRONJ.

Methods: Medical records of MRONJ patients who visited Mishima Dental Center, Nihon University School of Dentistry, during the period 2015-2021 were extracted. Counter-matched sampling design was used to select participants matched for sex, age, and smoking for this nested case-control study. The incidence factors were statistically examined by logistic regression analysis.

Results: Twelve MRONJ patients were used as cases and 32 controls were matched. After adjustment for potential confounders, injectable bisphosphonates (aOR = 24.5; 95% CI = 1.05, 575.0; P < 0.05) were significantly associated with the development of MRONJ.

Conclusion: High-dose bisphosphonates may be a risk factor for the development of MRONJ. Patients who use these products require careful prophylactic dental treatment against inflammatory diseases, and dentists and physicians should maintain close communication.

Purpose: To evaluate the clinical performance of two proposed onlay designs.

Methods: Molars with occlusal and/or mesial/distal defects after root canal treatment were classified by design into three groups. Onlays without shoulders were the control group (Group C, n = 50). The designed onlays were Group O (n = 50) and the designed mesio-occlusal/disto-occlusal onlays were Group MO/DO (n = 80). All onlays had an occlusal thickness of approximately 1.5-2.0 mm, and the designed onlays had a shoulder depth and width of approximately 1 mm. In Groups C and O, the box-shaped retention was 1.5 mm in depth. The proximal box was connected with a dovetail retention in Group MO/DO. Patients were examined every 6 months and followed for 36 months. Restorations were evaluated by using the modified United States Public Health Service Criteria. Statistical analysis was performed by using Kaplan-Meier analysis, the chi-square test, and Fisher's exact test.

Results: No tooth fracture, debonding, secondary caries, or gingivitis was observed in any group. Groups O and MO/DO had satisfactory survival and success rates, and there was no significant difference in performance characteristics among the three groups (P > 0.05).

Conclusion: The two proposed onlay designs were effective in protecting molars.

Purpose: Enterococcus faecalis (E. faecalis) is one of the major microorganisms that causes failure of endodontic treatment. This study aimed to investigate the antibacterial activity of apigenin and its synergistic effect with reduced graphene oxide (RGO) in treating E. faecalis biofilms.

Methods: The antibacterial activities were characterized by viability analysis including colony forming units and confocal laser scanning microscopy (CLSM) analyses. The effect on biofilm biomass was measured using a crystal violet staining method. Live and dead bacteria bio-volumes were determined by CLSM analysis, and the morphology of E. faecalis biofilm after treatment with apigenin and apigenin + RGO was observed by scanning electron microscopy (SEM).

Results: The viability of E. faecalis in biofilms decreased by apigenin treatment in a dose-dependent manner. While apigenin alone did not significantly affect the biofilm biomass, apigenin + RGO reduced the biomass in an apigenin concentration-dependent manner. Likewise, the bio-volume of live bacteria decreased and the bio-volume of dead bacteria increased in apigenin-treated biofilms. According to SEM images, apigenin + RGO-treated samples showed less E. faecalis in biofilms than apigenin-only treated samples.

Conclusion: The results suggested that the combined use of apigenin and RGO could be a potential strategy for effective endodontic disinfection.

To clarify the validity of analysis of masticatory movement using a two-dimensional (2D) mandibular movement recording device, masticatory movements (pattern of movement path, opening distance, masticatory width, and cycle time) were compared between simultaneous recordings made by 2D and three-dimensional (3D) devices in healthy adults. The 2D device can perform the same level of mandibular movement analysis as the 3D device if the distance between LED and camera is fixed (15 cm), and the findings indicated the suitability of the 2D device for clinical application.

Purpose: This study aimed to compare the biofilm removal and apical extrusion of sodium hypochlorite (NaOCl) following machine-assisted irrigation using a three-dimensionally (3D) printed dentin-insert model.

Methods: Multispecies biofilms were formed in a 3D-printed curved root canal model with dentin insert. The model was then placed in a container that was filled with 0.2% agarose gel containing 0.1% m-Cresol purple. Root canals were irrigated with 1% NaOCl using syringe irrigation, sonically agitated (EndoActivator or EDDY) or ultrasonically activated (Endosonic Blue) irrigation. Samples were photographed and the color-changed area was measured. Biofilm removal was assessed using colony-forming unit counting, confocal laser scanning microscopic analysis and scanning electron microscopic observations. The data were analyzed using one-way ANOVA, followed by Tukey test (P < 0.05).

Results: EDDY and Endosonic Blue demonstrated significantly greater reduction of biofilms compared to other groups. No significant differences were observed in the remaining biofilm volume in syringe irrigation and EndoActivator groups. Furthermore, EDDY and Endosonic Blue presented with numerous exposed dentinal tubules. EDDY showed significantly greater NaOCl extrusion compared to other groups.

Conclusion: Ultrasonic activation with a small-sized nickel-titanium file irrigation system may be beneficial in intracanal biofilm removal avoiding extrusion of NaOCl beyond the root apex.