Journal of oral science最新文献

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: To investigate a novel method that uses a single impression, facilitated by additive technologies, to fabricate a metal post and core and metal coping.

Methods: Twenty-four human single-rooted teeth were divided into two groups-one for use with a conventional two-appointment method (CT group) and the other for a novel, one-appointment method (OA group). The CT group required separate impressions and cast models for the metal post and core and coping. In contrast, the OA group used a novel single-impression method to obtain both the metal post and core and metal coping. Silicone replica technique was used to assess marginal and internal adaptation of the copings in each group. Statistical analysis was performed using the Mann-Whitney U test (α = 0.05). Additionally, three-dimensional digital evaluation was used for comparison of teeth and coping internal areas.

Results: The mean marginal gap did not significantly differ between the CT group (83.77 ± 51.84 µm) and OA group (77.09 ± 31.65 µm) (P = 0.8835). However, the CT group had significantly larger internal gaps (P < 0.05).

Conclusion: The findings suggest that it is feasible to fabricate a metal post and core and metal coping from a single impression.

Purpose: To quantify plastic waste (PW) generated during undergraduate clinical care in a private university dental center in Peru.

Methods: This cross-sectional study quantified PW produced during a 19-day period by five clinical sections and one radiology section in relation to type of care (n = 7) and procedure (n = 21) in 40 dental units (DUs). PW was characterized by type, composition, number, and weight. Results were projected by year and analyzed with the Kruskal-Wallis test, with P < 0.05 indicating statistical significance.

Results: The projected annual PW was 4,254.9 ± 2,498.1 kg, 22.2 ± 18.5% of which comprised DU protective film. The mean number of pieces and weight of PW per patient was 18.6 ± 15.5 pieces and 126.7 ± 166.2 g; however, the values were higher for pediatric dentistry (25.3 pieces) and periodontics (278.9 g) (P ≤ 0.0002). PW was classified into 53 types, eg, pure composition (65.3%), gloves mainly (21.4%), sterilization packaging (10.6%), and standard dental bibs (9.8%), and by proportion by weight, eg, disposable aprons (31.3%), gloves (21.4%), and dental bibs (11.2%).

Conclusion: Pediatric dentistry and periodontics generated the most PW by amount and weight. PW comprised personal protective equipment, sterilization packaging, and dental protective film. These results highlight the need to decrease waste and increase awareness of efforts to reduce the adverse environmental effects of dental practice.

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: Human dental caries is a troublesome disorder of the teeth, and the bacterium mostly responsible is Streptococcus mutans. The Cbm and Cnm genes, which encode the Cbm and Cnm proteins respectively, are two of the virulence factors associated with Streptococcus mutans strains. Oral appliances such as dental arches and brackets accelerate streptococcal colonization and caries formation. The aim of this study was to determine the gene frequency of Cnm and Cbm in Streptococcus mutans strains isolated from oral arches and brackets in orthodontics patients and their relationship to antibiotic resistance.

Methods: Four hundred seventy-three orthodontics patients were included in this study and 384 Streptococcus mutans strains were isolated from the arches and brackets of these patients. The strains were identified and verified using a Vitek-2 compact system and their antibiotic susceptibility was determined by the disc diffusion method. The presence of the Cbm and Cnm genes was confirmed by the PCR method.

Results: It was found that 2.08% of the strains the Cbm gene and 16.14% the Cnm gene. The rate of co-existence of these two genes was 0.78%.

Conclusion: Strains those harbored the Cbm and Cnm genes are more resistant to antibiotics and more likely to be major risk factors for caries in orthodontic patients.

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 present study investigated the effects of stabilization splints on two categories of sleep bruxism using a portable electromyographic recording system.

Methods: Twenty-six individuals confirmed as mild to severe bruxers by nocturnal masseter electromyographic episodes were enrolled in the study. Participants wore a stabilization splint during sleep for 30 nights, and masseter muscle activity was measured at baseline, immediately after, and 1 and 4 weeks after insertion of the splint. Bursts in masseter electromyographic episodes were separated into phasic bursts or tonic bursts, then each burst was analyzed in terms of duration, frequency, and magnitude of bursts.

Results: The frequency of phasic bursts significantly decreased immediately after insertion of the splint compared with the baseline. The geometric mean magnitude of tonic bursts decreased when wearing the splint compared with the baseline.

Conclusion: These findings suggest that stabilization splints reduce jaw-muscle activity during sleep in patients suffering from sleep bruxism by reducing the frequency of phasic bursts in the short term and reducing the magnitude of tonic bursts over a longer period.

This study aimed to evaluate the stick behavior and performance of an adhesive for facial prostheses on esthetics and strength. Forty subjects participated in this study. Mimic the skin was fabricated, applied to one cheek of each subject using only medical adhesive, and to the opposite cheek using the same medical adhesive and an overlying film dressing. Ninety-five percent of subjects reported that the silicone prosthesis with film dressing did not peel off and was less noticeable. The combination of medical adhesive and film dressing provided stronger adhesion and better esthetics compared to medical adhesive alone.

Purpose: As three-dimensional (3D) intraoral scans are becoming popular in modern dentistry, they also offer a new category of antemortem data for forensic identification. This study proposes a novel methodology for individual identification based on 3D homologous models of the maxilla.

Methods: Data from 100 maxillary plaster casts (40 monozygotic twin casts, 28 dizygotic twin casts and 32 singleton casts) were used. From the initial sample, 10 casts were randomly chosen and duplicated four times, resulting in 40 duplicates. These were divided into four groups and subjected to the following alterations: molar attrition (n = 10), canine attrition (n = 10), molar and canine attrition (n = 10), and no alteration (n = 10). All the casts were converted to 3D models and then to homologous models using a template with 24 landmarks. The 3D coordinates of each vertex in the homologous model were then calculated and used for statistical comparison of similarity between two given homologous models using the average Hausdorff distance.

Results: All four groups achieved accurate matching with their original maxillary casts, with a minimal average Hausdorff distance.

Conclusion: This method accurately identified individuals, including monozygotic twins, and exhibited robustness against minor tooth attrition, demonstrating its feasibility as an identification method in actual forensic settings.