The Chinese journal of dental research : the official journal of the Scientific Section of the Chinese Stomatological Association (CSA)最新文献

Objective: To undertake a joint analysis of the influence of fracture width, dental thickness and distance of the fracture from the cortical bone on the radiographic diagnosis of vertical root fractures.

Methods: Thirty-six uniradicular bovine teeth were endodontically treated and distributed into three groups according to the remaining root dentine thickness: 1.2 mm, 1.5 mm and 1.8 mm. Each group comprised 12 teeth, six with vertical root fracture and six without. Scanning electron microscopy (SEM) images of the fractured tooth groups were obtained and the fracture lines were measured. All specimens were inserted into bone defects created in bovine ribs, at different distances from the external cortical bone. Digital periapical radiographs were randomly evaluated by three blinded examiners (presence or absence of fractures).

Results: The specificity for periapical radiography was found to be 89% and the accuracy rate was 57.4%. The mixed-model regression using the generalised estimating equation (GEE) model showed that the width of the fracture line and the thickness of the dental remnant play an important role in radiographic detection of vertical root fractures. There is a lower chance of correct diagnosis with fracture line widths < 0.2 mm (odds ratio [OR] 0.294, 95% confidence interval [CI] 0.103 to 0.836; P = 0.022) and tooth thicknesses < 1.2 mm (OR 0.342, 95% CI 0.157 to 0.747; P = 0.007).

Conclusion: Fracture line widths < 0.2 mm and smaller root thicknesses lead to a less accurate diagnosis of vertical root fractures on periapical radiographs.

Objective: To determine the impact of social support on perceived stress in Latin American and Caribbean dental students and dental practitioners during mandatory social isolation within the coronavirus (COVID-19) pandemic in 2020.

Methods: A cross-sectional study was conducted with a sample of 1812 dental students and dental practitioners from 21 Latin American and Caribbean countries. Perceived stress was assessed using the perceived stress scale (PSS-14), and the influence of social support was addressed using the Duke-UNC-11. Additionally, sociodemographic variables, knowledge of and preventive behaviour against COVID-19 and health status were considered. A descriptive, bivariate and multivariate analysis was performed through multiple linear regression.

Results: In the multivariate analysis, model 4 presented R2% = 21.20 (P < 0.001), a constant of 40.049; within the model, the social support variable had a non-standardised regression coefficient (b) of -4,527 (95% CI - 5.646 to -3,408; P < 0.001), the self-perceived level of concern regarding COVID-19 was b = 1.838 (95% confidence interval [CI] 0.887 to 2.790; P < 0.001), the self-perceived health status was b = -2.191(95% CI -2.944 to -1.437; P < 0.001), the number of days in compulsory isolation was b = -0.965 (95% CI -1.908 to -0.022; P = 0.045), while the level of confinement was b = 0.923 (95%CI: 0.106-1.740; P = 0.027), age was b = -1.743 (95% CI -2.625 to -0.860; P < 0.001), sex was b = 1.324 (95% CI 0.311 to 2.337; P = 0.011) and the economic income level was b = -1.539 (95% CI -2.434 to -0.644; P = 0.001).

Conclusion: An association was determined between perceived stress and social support, as well as the variables of concern about the disease, self-perceived health status, number of days and level of confinement, age, sex and economic income level, based on the experience of dental practitioners and dental students in mandatory isolation.

Objective: To investigate the differences between temporomandibular articular fossa bone surface and the envelope surface of the mandibular condyle movement.

Methods: Thirty-four healthy adults underwent skull base and mandible scans using CBCT and performed mandibular border movement using the mandibular movement recording system. Landmarks of the fossa and tubercle were indicated and distance and angle parameters were measured on the 3D models reconstructed from the CBCT. The condyle movement envelope surfaces were formed according to models reconstructed from CBCT and the mandibular movement trajectory using computer simulation. The highest and lowest points of the envelope surface were indicated to create parameters. The data were analysed using a paired t test in SPSS (version 24.0, IBM, Armonk, NY, USA).

Results: The mandibular fossa bone surface was statistically different to the envelope surface for the height of the first peak of the envelope surface (3.280 ± 1.319 mm) and depth of the mandibular fossa (6.338 ± 2.389 mm) (the ratio was 51.75%), the height of the second peak of the envelope surface (1.463 ± 0.745 mm) and the height of the tubercle (2.000 ± 0.968 mm) (the ratio was 73.15%), and the downwards angle of the envelope surface (25.933 ± 7.539 degrees) and the posterior slope angle of the articular tubercle (35.059 ± 5.224 degrees) (the ratio was 73.97%).

Conclusion: The downwards angle of the envelope surface was statistically significantly smaller than the posterior slope angle of the articular tubercle, suggesting that the condyle movement is flatter than the mandibular fossa bone surface.

Objective: To determine the prevalence, frequency and distribution of dental anomalies that were detectable on panoramic radiographs in a large sample Turkish population, and the associations among the anomalies.

Methods: This study was conducted retrospectively on panoramic radiographs of 43,880 patients who were admitted to the Faculty of Dentistry at Trakya University, Edirne, Turkey. Patients' files were examined by two observers and radiographic images of 2265 patients with at least one dental anomaly were included. Dental anomalies were classified as anomalies in the number, structure, position and shape of teeth. The interactions between the groups were analysed using chi-square tests.

Results: The study group consisted of 1336 women (59%) and 929 men (41%) with a mean age of 33.3 ± 14.4 years. A total of 2265 patients, with a prevalence of 5.2% (2265/43880), had at least one dental anomaly. The most frequent anomalies were in position (2.7%) and number (2.1%). Structure anomalies were least common, affecting 0.02% of patients. Among the study group of patients with dental anomalies, 12.2% presented more than one kind of anomaly.

Conclusion: Position anomalies were the most common dental anomaly, whereas structural anomalies were least common in a Turkish sample. The prevalence of anomalies varies between populations, confirming the role of racial factors.

Objective: To evaluate the accuracy of 10 intraoral scanners for single-crown and three-unit preparation models.

Methods: A maxillary partially edentulous model was fabricated. A dental cast scanner was used to obtain standard tessellation language (STL) data. Ten intraoral scanners, namely Trios 2 (TR2; 3Shape, Copenhagen, Denmark), True Definition (TD; 3M, Saint Paul, MN, USA), CEREC AC Omnicam (OM; Dentsply Sirona, Charlotte, NC, USA), Organical Scan Oral (OS; R+K, Berlin, Germany), PlanScan (PS; Planmeca, Helsinki, Finland), DWIOP (DW; Dental Wings, Montreal, Canada), Xianlin (XL; Hangzhou Xianlin, Hangzhou, China), DL-100 (DL; Guangzhou Longcheng, Guangzhou, China), Trios 3 (TR3; 3Shape) and i500 (MD; MEDIT, Seoul, South Korea) were used to obtain stereolithography data as test groups. Trueness, precision and surface accuracy were evaluated by deviation analysis using 3D image processing software. One tooth with a three-unit preparation for each test group was registered with the reference scan data, and the absolute distance from another tooth was calculated as the absolute accuracy. The data were analysed using a Mann-Whitney U test and Dunn-Bonferroni test (α = 0.05).

Results: The best trueness, precision and surface accuracy of scanning single crown preparation were recorded with TD (trueness 2.9 μm and precision 1.9 μm) and XL (surface accuracy 20.3 ± 2.9 μm). The best trueness, precision, surface accuracy and absolute accuracy of three-unit preparations were recorded with TD (2.6 μm), XL (1.9 μm), OM (27.1 ± 5.2 μm) and TR3 (79.2 ± 19.6 μm), respectively. There was no statistically significant difference in trueness between single- and multiple-unit preparations for any of the intraoral scanners (P > 0.05). A statistically significant difference in the surface accuracy between single and multiple preparations was found for TR2, TD, OM, DW, XL, DL and MD (P < 0.05).

Conclusion: The trueness and precision of intraoral scanners for scanning three-unit preparations were nearly the same as those for single-crown preparations; however, with the exception of OS, PS and TR3, the surface accuracy of single-crown preparations was significantly better than that for three-unit preparations.

Traditional techniques for fabricating interim, immediately loaded implant-supported full-arch prostheses are complex and time-consuming. The present study presents an efficient technique for fabricating interim prostheses with prefabricated multipurpose rigid connecting bars. This technique can minimise the misfit attributed to the polymerisation shrinkage of resin and expansion of the working cast, and simultaneously facilitate impression taking and occlusal records in one visit, thus reducing laboratory and chair time. Due to its ease of use and clinical efficiency, the present technique is considered particularly beneficial for immediate loading rehabilitation.

Objective: To evaluate the prevalence of temporomandibular disorder (TMD) in dental faculty students in different years of education and investigate the relationship between TMD and oral habits or quality of life.

Methods: The Fonseca Anamnestic Index (FAI) questionnaire was used to determine the prevalence and severity of TMD, the Oral Behaviors Checklist (OBC) questionnaire served to determine the severity of harmful oral habits/parafunctions and the Oral Health Impact Profile-14 (OHIP-14) questionnaire was used to evaluate the quality of life in a total of 452 dentistry students (269 women and 183 men) in different years of education.

Results: With regard to incidence of TMD, a total of 215 women had TMD (215/269, 79.9%), which was significantly higher than that in men (87/183, 47.5%) (P < 0.001). According to the OBC and OHIP-14 questionnaire results, harmful oral habits and quality of life showed a low to moderately significant correlation with TMD (P < 0.05).

Conclusion: The Fonseca, OHIP-14 and OBC questionnaires allow early and inexpensive determination of oral habits that increase the prevalence of TMD. The prevalence of TMD in dentistry students at the clinical education stage is higher than those who have not progressed to the clinical education stage.

Objective: To assess bone volume stability and identify critical bone graft thickness for guided bone regeneration (GBR) simultaneous to implant placement in the maxillary anterior region.

Methods: Eighteen patients were included in the study and received placement of one maxillary anterior implant combined with GBR using deproteinised bovine bone mineral (DBBM) and resorbable collagen membrane. The multilevel buccal bone thickness (BT) was measured by CBCT 1 to 2 weeks and 5 to 8 months post-implantation (at implant uncovering surgery).

Results: Significant buccal alveolar crest collapse (ACCb 1.20 to 1.70 mm) occurred during the mean healing period of 5.3 months (P = 0.000). A greater percentage of ACCb occurred at the coronal aspect of the implant, with 59.24% ± 19.22% at the implant platform and 34.10% ± 30.50% 6.0 mm below the implant platform, respectively. Linear regression analysis demonstrated that if BT was 1.8 to 2.0 mm at the implant platform at uncovering surgery, then it was estimated to have been 4.1 to 4.5 mm immediately post-implantation.

Conclusion: ACCb after maxillary anterior implant placement with simultaneous GBR occurred more coronally than apically. Excessive alveolar ridge augmentation, up to 4.0 mm of hard tissue buccal to the implant platform, should be achieved at the time of surgery to compensate for this potential resorption.

Objective: To investigate the effects of dental anxiety on fluctuations in blood pressure (BP) and heart rate (HR) during tooth extraction in hypertensive patients under local anaesthesia, and how they are influenced by various confounding variables.

Methods: This is a prospective repeated-measures cohort study involving 600 patients successively recruited from Peking University School and Hospital of Stomatology, Beijing, China. BP and HR were repeatedly measured at rest (T0), before anaesthesia (T1), during tooth extraction (T2) and after tooth extraction (T3). Anxiety status was measured prior to local anaesthesia using a modified dental anxiety scale (MDAS). Three groups were assigned: mild anxiety (Corah DAS score of 4 to 8), moderate anxiety (score of 9 to 12) and severe anxiety (score of 13 to 20). We used a generalised linear mixed model (GLMM) to analyse the effects of dental anxiety on fluctuations in BP and HR. Interaction analysis was used to further explore the correlationship between these interactive factors.

Results: The mean anxiety scale score was 9.63 ± 2.88. Severe preoperative anxiety (score of 14 to 20) was associated with significantly increased HR during administration of anaesthesia. Patients with severe anxiety also displayed a significantly greater increase in HR during anaesthetic administration (P < 0.001). When analysing the joint effects of different anxiety statuses over time, blood pressure was significantly elevated in all patients with moderate and severe anxiety during tooth extraction at T2 (β = 1.25, 95% CI 0.24 to 2.27). We also observed a significant decrease in HR in the moderate anxiety group at T3 (β = -1.51, 95% CI -2.38 to -0.63) and a significant increase in HR in the severe anxiety group at T1, T2 and T3 (β = 2.52, 95% CI 1.12 to 3.93; β = 3.84, 95% CI 2.30 to 5.38; β = 4.57, 95% CI 3.03 to 6.11, respectively).

Conclusion: This study indicates that the effects of dental anxiety on BP and HR in middle-aged and elderly patients with hypertension during local anaesthesia and tooth extraction were influenced by various confounding variables.