Journal of oral science最新文献

Purpose: The purpose of this study was to investigate the influence of graphene oxide (GO) and hydrothermal aging on the biaxial flexural strength (BFS) and translucency (TP) of ultrathin monolithic zirconia with different yttria concentrations.

Methods: Disc shaped specimens (n = 120) were milled using zirconia blocks (YZ-HT [HT], YZ-ST [ST], and YZ-XT [XT]) with a diameter of 15.0 mm and a thickness of 0.5 mm. Half of the specimens were immersed in 0.2 wt% GO-water dispersion (HTG, STG, and XTG) and subjected to hydrothermal aging for 10 h. The TP was measured using a reflection spectrophotometer and BFS was tested in a universal testing machine. Data were statistically analyzed with 2-way analysis of variance followed by post-hoc comparisons (α = 0.05).

Results: The lowest mean TP was found in the group of STG aged for 10 h. Hydrothermal aging significantly decreased the TP values in the groups of HTG, STG, and XTG (P < 0.05). Significantly higher TP values were obtained in the groups of XT. Immersion in 0.2 wt% GO-water dispersion significantly improved the BFS values of STG, and XTG for the control and aged groups.

Conclusions: GO leads to decreased translucency while improving BFS for highly translucent zirconia ceramics.

Purpose: Separation of instrument fragments can impede the progress of endodontic treatment, and effective management of this complication is crucial for treatment success. This study examined the factors that impact the success of retrieval of separated instrument fragments by postgraduate endodontic residents.

Methods: A retrospective analysis was conducted on a total of 224 teeth associated with instrument fragment separation that were managed by postgraduate residents specializing in endodontics between January 2020 and March 2024. Data were extracted from patient records, periapical radiographs, and clinical notes. Chi-squared test and t-test were employed to identify factors significantly influencing retrieval success. Associations between successful retrieval and variables were assessed using binary logistic regression models.

Results: Fragment retrieval was successful in 32% of the examined cases. Retrieval was more likely to be successful for anterior teeth than for premolars and molars (P = 0.003). Fragment separation in the coronal third of the canal had a higher retrieval success rate (P < 0.001). Longer separated fragments were also associated with increased retrieval success (t = 3.035, P = 0.003).

Conclusion: The study revealed that factors critically influencing the successful retrieval of separated instrument fragments included the tooth type, the level of separation within the canal, and the fragment length. These findings highlight the importance of careful case selection in order to optimize management outcomes.

Purpose: Examination of patients to detect periodontal disease is important for diagnosis and treatment planning, and accuracy of examination may be improved if salivary components can be applied for diagnosis. Leucine-rich α2 glycoprotein (LRG) is expressed in the serum of patients with inflammatory diseases, and salivary LRG may be applicable to the diagnosis of periodontal disease.

Methods: To evaluate the effect of initial periodontal therapy (IPT) on clinical periodontal parameters such as probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), periodontal inflamed surface area (PISA), periodontal epithelial surface area (PESA), saliva samples were collected before and after IPT from 63 patients with chronic periodontitis. The amount of LRG protein in saliva was measured by enzyme-linked immunosorbent assay.

Results: Salivary LRG levels of 30 patients with Stage III, Grade B or C periodontitis (Severe group) were higher than the LRG levels of 33 patients with Stage Ⅰ or Ⅱ, Grade A periodontitis (Mild group). LRG levels in the Severe group significantly decreased after IPT. Positive correlations were found between salivary LRG levels and mean PD, CAL, BOP rate, PISA and PESA.

Conclusion: These results suggest that there is an association between salivary LRG levels and severity of periodontitis.

Purpose: This study aims to evaluate the cytotoxicity of implant luting cements and to visualize the morphological changes in the cells.

Methods: Seven experimental groups Cem Implant Cement (CIC), EsTemp Implant Cement (EIC), Harvard Implant Cement (HIC), MIS Crown Set Implant Cement (MCIC), Oxford Cem Implant Cement (OCIC), Premier Implant Cement (PIC), and Adhesor Carbofine (ZPC) were generated including one conventional, and six implant cements (n = 9). Specimens were applied to human fibroblast cell (HGF) and mouse pre-osteoblast cell line (MC3T3-E1) cells by direct contact and extract text methods. The extracts were prepared by sterilizing the discs under ultraviolet light for 24 h in a cell culture medium at 37°C, 5% CO, and 95% humidity. Cell lines were confluent in the cell culture module in 25 cm² and 75 cm² flasks in a carbon dioxide incubator with 5% CO and 95% humidity. Discs and extracts were placed in a 96-well plate. Cell viability was evaluated after 24 h by means of a cell proliferation assay with 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxyanilide (XTT assay).

Results: Dual-cured OCIC and HIC cements comprising methacrylate and zinc oxide elicited relatively lower cytotoxicity than self-cure cements with various compositions. The OCIC revealed the highest cell viability (89%) in the extract method on the HGF cells. Immortalized MC3T3 cells showed more sensitivity to cement exposure than the primary HGF cells.

Conclusion: All tested cements elicited a cytotoxic effect with differences depending on cell type and cement material in extract and direct contact methods. Dual polymerized semi-permanent cement (OCIC) showed higher cell viability in the extract method.

Purpose: This study compares the ability of extrinsic stain removal and surface roughness changes on tooth surfaces after using two different types of dental air polishing powder: Sodium bicarbonate and novel eggshell powder.

Methods: For the study of extrinsic stain removal, twenty bovine teeth were soaked in coffee for extrinsic stain formation. Group 1 and Group 2 were polished with sodium bicarbonate powder and novel eggshell powder, respectively. The acquired stains of teeth were recorded as baseline, and color changes after cleaning with two different powders were also measured by colorimeter. Sixteen samples from eight human posterior teeth were used for the surface roughness test. Surface roughness values (S_a) of two groups (sodium bicarbonate and novel eggshell powder) were measured by a contact-type profilometer before and after polishing with two types of powders.

Results: The data showed that the average ΔE* value of the sodium bicarbonate group was higher than that of the novel eggshell powder group (P < 0.05). The average ΔS_a value of the sodium bicarbonate group was higher than that of the novel eggshell powder group (P < 0.05).

Conclusion: Sodium bicarbonate powder showed higher stain removal ability and surface roughness changes than the novel eggshell powder.

Purpose: Coffee consumption is a well-known contributor to tooth discoloration, and the extent of staining is influenced by the chemical composition of the coffee. This study investigated the associations of coffee roasting level, chlorogenic acid (CGA) content, absorbance level, and their combined effects with tooth discoloration.

Methods: Bovine tooth enamel specimens were immersed in light, medium, and dark roasts of four coffee types (two Arabica and two Robusta coffees) for 72 h. High-performance liquid chromatography (HPLC) was used to measure CGA content, absorbance levels were estimated by using pigment concentration, and discoloration was assessed by spectrophotometry. The data were analyzed with the Friedman test.

Results: Medium roasts induced the greatest discoloration, and tooth specimens immersed in Ethiopia Arabica exhibited the greatest color difference based on CIEDE2000 (ΔE₀₀ at 72 h: 13.51 ± 4.63). Light roasts induced the least staining, despite having the highest CGA content. Dark roasts showed the highest absorbance, indicating a higher pigment concentration. Friedman analysis revealed a significant difference in color change in relation to roasting level for all coffee types.

Conclusion: The present findings indicate that tooth discoloration is caused by the complex interaction of CGA, melanoidins, and roasting level. Because of the interplay of these factors, medium roasting had the greatest effect on discoloration.

Purpose: The purpose of the present study was to evaluate the effects of dental stone molds and three dimensional (3D)-printed molds on the color difference, translucency, surface roughness, and hardness of maxillofacial silicones.

Methods: To prepare molds, a rectangular body 20 mm in diameter and 2 mm in thickness, was designed with computer-aided design software. Two different dental gypsum molds were prepared with the lost-wax technique. Silicone mixture was poured into molds and polymerized at room temperature for 24 h. Color parameters were measured using a spectrophotometer. A profilometer was used for measuring surface roughness, and Shore A values were obtained with a durometer.

Results: Color change (ΔE₀₀) values of the 3D-resin group (1.53 ± 0.35) were significantly lower than others. The highest translucency parameter (TP) values belonged to the stainless steel group (12.44 ± 0.65). Surface roughness values (Ra) of the stainless steel group (0.28 ± 0.06) were significantly lower than other groups. The mean Shore A value of the 3D-resin group (23.90 ± 1.37) was significantly higher than the blue gypsum group (21.53 ± 0.93).

Conclusion: Lower color difference and higher Shore A values were examined with 3D-printed resin molds. The highest TP values and lowest Ra values were obtained when stainless steel was used for molding of maxillofacial silicone.

Purpose: This study investigated the synergistic effects of reduced graphene oxide (RGO) on the antibacterial activity of three calcium hydroxide-based intracanal medicaments with different vehicles.

Methods: Multispecies biofilms were cultured in a bovine root canal model. Intracanal medicaments containing nonaqueous vehicles, including N-methyl-2-pyrrolidone (NMP; CleaniCal), propylene glycol (PG; UltraCal XS), and polyethylene glycol (PEG; Calcipex II), were placed in the model. The synergistic effects of RGO were evaluated by analyzing colony-forming units, extracellular deoxyribonucleic acid (eDNA) levels, and findings from confocal laser-scanning microscopy (CLSM) and scanning electron microscopy. To evaluate the cytotoxicity of each vehicle, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed. To determine whether RGO altered the physicochemical properties of the medicaments, flowability and pH were measured. A P-value of <0.05 was considered to indicate statistical significance.

Results: In the CleaniCal group, bacterial viability, eDNA levels, and extracellular polymeric substrate (EPS) were significantly lower in the presence of RGO. However, only bacterial viability significantly differed in the other groups. PEG resulted in the highest cell viability among the vehicles. Furthermore, there was no significant difference in flowability or pH in relation to the inclusion of RGO.

Conclusion: The results suggest that RGO enhances the antibacterial effect of intracanal medicaments containing NMP.

Purpose: This study aimed to characterize the 3-dimensional morphology of larger recurved caniniform teeth (LrCTs) and their underlying intraosseous structures in Caprodon schlegelii.

Methods: Specimens (n = 5) with a total length of approximately 32 cm were fixed and processed for micro-computed tomography and/or stereomicroscopy. Volume data of the LrCT-bearing jaws were examined using volume rendering images.

Results: The LrCTs were identified in six locations on the jawbones: anteriorly, a pair of LrCTs in each of the jaw quadrants, and posteriorly, tandemly aligned rows of LrCTs in the dentary bones. In both cases, two adjacent LrCTs were in different stages of tooth life, namely, developmental and functional stages. Large intraosseous chambers contained the tooth germ area or were connected to the pulp of the overlying LrCTs. In the lower jaw, the chambers beneath the anterior and posterior LrCTs were connected to the canal systems, which were distributed in the lower and upper halves of the dentary bone, respectively.

Conclusion: The presence of LrCTs in six different locations on the jaws is a distinguishing feature of C. schlegelii, and a balanced replacement between developing and functional LrCTs is likely to ensure the mode and behavior of feeding in this species.

Purpose: The purpose of this study was to analyze the association between the number of medications and oral functions.

Methods: The study participants were selected from individuals who were attending regular follow-up as hospital outpatients. Patient profiles, the number of medications used, and measured values of oral function were extracted. These data were analyzed statistically for sex, age, and grouping according to the number of medications taken (no medication, G1; 1-4 medications, G2; ≥5 medications, G3). Conditional logistic regression analysis was performed to evaluate the effects of medications on oral function.

Results: A total of 172 patients (66 males and 106 females) were registered; 50 participants belonged to G1, 68 to G2, and 54 to G3. Significant inter-group differences were identified for tongue-lip motor function (oral diadochokinesis: ODK) and maximum tongue pressure in terms of age, but not in terms of sex. G3 showed significantly lower ODK than G1, and logistic regression analysis revealed that the number of medications was significantly associated with ODK/pa/. Age and MTP also significantly affected ODK/ta/ and /ka/.

Conclusion: Within the limitations of this study, the present findings suggest that the number of medications taken has an impact on tongue-lip motor function.