Journal of oral science最新文献

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.

Purpose: This study evaluated the effects of sintering temperature on the crystal structure, optical and thermal properties, and surface roughness and topography of nanolithium disilicate ceramics (NLDS) and zirconia-reinforced nanolithium silicate ceramics (ZNLS).

Methods: One hundred and twenty specimens of each ceramics were prepared and divided into 4 groups on the basis of sintering temperature. The specimens were then subjected to X-ray diffraction (XRD), spectrophotometric analysis of optical properties, differential thermal analysis (DTA), thermal gravimetrical analysis (TGA), roughness analysis, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectrometry. The data were analyzed using one-way analysis of variance followed by Tukey's test (α = 0.05)Results: XRD confirmed the presence of lithium disilicate, lithium phosphate, lithium metasilicate, and quartz in NLDS and ZNLS specimens. TGA, DTA, and average roughness did not significantly differ between groups (P < 0.05). Among NLDS groups, NLDS4 had ∆E values that significantly differed from those of the other groups (P < 0.05). EDX showed that NLDS2 had the highest Si value (25.3 ± 0.1 wt%) followed by NLDS4 (24.8 ± 0.1 wt%). Among ZNLS groups, ZNLS2-4 had a clinically acceptable ∆E. EDX analysis showed no significant difference for any group.

Conclusion: Sintering temperature did not affect the evaluated properties of NLDS. However, sintering ZNLS at different temperatures might affect the tested properties.

Purpose: This study used descriptive and inferential statistics to evaluate healing complications and survival time of avulsed permanent teeth.

Methods: Records of children and adolescents with avulsion injury were identified, and data on age, gender, cause of trauma, number of affected teeth, and status of other teeth and supporting tissues were analyzed. In addition, data on root formation status, duration and medium of extraoral storage, and healing complications of avulsed and replanted permanent teeth were obtained for patients who attended follow-up appointments.

Results: During a period of almost 20 years, 187 permanent teeth of 138 patients were avulsed. Avulsion injuries were more frequent in males and at 10-12 years of age. Falls were the main cause of avulsion, and the teeth most frequently affected were the maxillary central incisors. Seventeen of 51 replanted and followed teeth were retained. Retention was shorter for teeth stored in dry medium. Duration of tooth retention was positively correlated with patient age at the time of trauma. The most common healing complications were ankylosis (70.6%) and inflammatory root resorption (54.9%).

Conclusion: Outcomes of traumatic injuries are multifactorial, and favorable storage conditions, shorter duration of extraoral storage, and biological response are important for survival of avulsed teeth.

Purpose: This study aimed to evaluate the removal efficiency of three different intracanal medicaments using either single-syringe irrigation (S-SI) or multiple ultrasonic-activated irrigation (M-UAI).

Methods: Forty-two extracted human mandibular premolars were prepared to a size of 30/0.06 taper and randomly assigned to two irrigation groups: S-SI and M-UAI. Each group was subdivided based on the intracanal medicament used: Calcipex II (calcium hydroxide-based; CP), Calfee paste (calcium hydroxide-based; CF), or Bio-C Temp (calcium silicate-based; BT) (n = 7 each). After 1 week of storage under 100% humidity at 37°C, the samples underwent removal using either S-SI (1.5 mL sodium hypochlorite, 30 s) or M-UAI (1.5 mL, sequentially: 17% ethylenediaminetetraacetic acid, distilled water, 6% sodium hypochlorite, and distilled water, with 30-s activation for each). Residual intracanal medicament volume was assessed using micro-computed tomography. Statistical analysis was performed using the Kruskal-Wallis test and Mann-Whitney U test (α = 0.05).

Results: In S-SI, CF was removed more effectively than CP. In M-UAI, CF and CP showed similar rates, whereas BT had a significantly lower removal rate.

Conclusion: Removal efficiency varied among medicaments. CF demonstrated superior removability under both S-SI and M-UAI protocols compared with CP and BT.