Journal of Dental School

Objective(s): The current study aimed to investigate the level of dentists' knowledge and understanding of traumatic dental injuries (TDIs) to pinpoint specific areas where emergency dental care protocols and practices can be enhanced and optimized. Methods: A cross-sectional survey of 70 dentists in the city of Ilam, Iran, explored their knowledge, attitudes, and practices concerning TDIs. Data were collected using a researcher-developed questionnaire encompassing demographic information, a history of trauma-related training, and responses to 15 TDI-related questions, which were scored according to pre-defined criteria. Statistical analysis included analysis of variance (ANOVA), Tukey's honestly significant difference [HSD] test, Chi-square test, and t-test at p<0.05. Results: While gender did not demonstrate a statistically significant correlation with knowledge levels (p = 0.19), dentists who frequently treated TDI exhibited significantly higher awareness (p = 0.04). Prior training in TDI management, history of retraining, and years of practice exhibited no significant influence on awareness scores. Overall, participants achieved a mean accuracy of 43.4% on TDI-related questions, and no participant demonstrated a lack of basic knowledge. Conclusion: This study demonstrated a significant deficiency in dentists' understanding of emergency management protocols for TDIs, particularly concerning the diagnosis of intricate cases and the handling of associated complications. This highlighted the necessity for continued professional development and training in emergency dental care.

Objective(s): Dental composites' color stability is a key element in aesthetic and restorative treatments. This study investigated the effect of dry and wet polishing and finishing on the staining susceptibility of nanohybrid and microfill composites. Methods: In this study, 48 composite samples (24 microfill, 24 nanohybrid) were prepared. Three subgroups (control (C), wet finishing and polishing (W), and dry finishing and polishing (D)) were established for each composite group. The color was observed before and after the samples were placed in the coffee solution for 48 hours and the color change was measured. Data was statistically analyzed by one-way ANOVA and Tukey's post hoc test at p<0.05. Results: In the microfill group, the color change in group C (5.16 ± 2.49) was significantly lower than in group D (13.79 ± 3.10) (p<0.001). The mean color change in group C was lower than in group W (8.15 ± 2.40), but this difference was not statistically significant (p=0.089). In the nanohybrid group, the color change of group C (5.90 ± 1.36) was significantly lower than the W (11.91 ± 2.7) and D (11.97 ± 2.21) groups (p < 0.001). The color change difference between subgroups D and W was not statistically significant (p=0.998). Conclusion: Composite surfaces cured under the Mylar strip without finishing and polishing exhibited the least color change in both types of composites. Wet finishing and polishing improved the color stability of microfill composites; however, in nanohybrid composites, dry and wet finishing were almost similar.

Objective(s): The interplay between masticatory muscle function and dental arch size holds considerable significance within the discipline of orthodontics. This research endeavored to quantify masseter muscle dimensions via ultrasonography (USG) and subsequently analyze their correlative relationship with dental arch width. Methods: 45 participants were enrolled in this cross sectional study, stratified by gender and age cohorts. Bilateral USG assessments, utilizing a 7.5 MHz linear transducer, were conducted to quantify masseter muscle thickness and anterior-posterior (AP) width during both relaxed and clenched states. Intermolar width was determined through direct measurement with a metal caliper on dental casts of the maxillary and mandibular arches. Independent samples t-tests were employed to analyze mean differences between male and female subjects. The association between masseter muscle dimensions (thickness and width) and intermolar width was evaluated using Spearman's rank correlation coefficient and Pearson's correlation coefficient, as appropriate at p<0.05.  Results: The study cohort comprised 20 females and 25 males within the age range of 16 to 30 years. Statistically significant sexual dimorphism was observed, with males demonstrating substantially greater masseter muscle thickness and AP width compared to females in both relaxed and clenched states (p < 0.001). Consistent with expectations, males demonstrated statistically significant greater intermolar widths in both the maxilla and mandible (p < 0.001). Across the entire study population, a statistically significant positive correlation was identified between masseter muscle thickness and intermolar width (p < 0.05). Specifically, individuals exhibiting larger masseter muscle dimensions presented with correspondingly increased intermolar widths in both the maxillary and mandibular arches. However, when these variables were stratified by gender or age group, no statistically significant correlations were observed (p > 0.05). 

Conclusion:USG is validated as a safe and reproducible technique for the objective measurement of masseter muscle thickness.

Objective(s): This research investigated the influence of Ascophyllum nodosum (A. nodosum) and Punica granatum (P. granatum) extracts on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus). Methods: In this laboratory-based study, the antibacterial effects of aqueous-acidic, ethanolic, and methanolic extracts of A. nodosum, along with the hydroalcoholic extract of P. granatum were analyzed against S. mutans and L. acidophilus using the disc diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts were determined through broth microdilution and macrodilution techniques. As a positive control, 0.2% chlorhexidine (CHX) was utilized, and all experiments were performed in triplicate. Statistical analyses included ANOVA, the Bonferroni test, and Kruskal-Wallis at p<0.05. Results: CHX exhibited the highest inhibitory and bactericidal effects on both bacterial strains. While both extracts showed antibacterial potential against both organisms, their efficacy was significantly lower than that of CHX (P<0.05). The following CHX, aqueous acidic extract of A. nodosum and the hydroalcoholic extract of P. granatum demonstrated superior MIC and bacteriostatic activity against S. mutans. For L. acidophilus, the hydroalcoholic extract of P. granatum showed the best results. 

Conclusion: The results indicated that extracts from A. nodosum and P. granatum possess considerable antibacterial properties against S. mutans and L. acidophilus.

Objective(s): Accurate shade selection is the most challenging step in the natural reconstruction of teeth in most cases. The most commonly used method for adapting the color of tooth and restorative materials is the visual matching of the tooth color to shade guides. However, many factors affect color perception by the observer, making the visual evaluation of tooth color unreliable. Therefore, this study aimed to compare the reproducibility of tooth shade determination with two different types of spectrophotometers and two smartphone applications. Methods: The present in vitro study used four methods of colorimetry on 27 disk-shaped composite resin samples prepared from nine different shades of composite resin. Colorimetry tools included Easyshade (Vita, Germany) and SP60 (X-rite, USA) colorimetry devices, and two smartphone colorimetry applications: Color Grab and Dental Shade Navigator. Statistical analysis was performed using intraclass correlation coefficient (ICC) and repeated measures ANOVA at p<0.05. Results: The results indicated significant differences(P-value<0.05) among the four colorimetry methods, with the following reproducibility rates based on the ΔE parameter: SP60 spectrophotometer: 100%; Color Grab Software: 95.1%; Easyshade spectrophotometer: 40.7%; and Dental Shade Navigator Software: 34.4%. Conclusion: The SP60 spectrophotometer had the highest reproducibility in all the color parameters, followed by the Color Grab application. Easyshade device had a higher reproducibility rate than the Dental Shade Navigator Software.

Objective(s): Microcrack formation during endodontic treatment is a major concern because it can compromise the success of the procedure. Although rotary nickel-titanium files have become the standard of care for canal shaping, there is some concern that they may be more likely to cause microcracks than other types of files. This study evaluated the incidence of microcracks in mandibular and maxillary molars after using three different rotary file systems. Methods: This in vitro experimental study investigated 51 canals in 30 periodontally compromised mandibular and maxillary molars. Prior to root canal instrumentation, micro-computed tomography (micro-CT) imaging was conducted. The canals were subsequently categorized into three groups (N=17), prepared using the OneShape, 2Shape, and OneCurve rotary file systems; and re-evaluated using micro-CT. Statistical analysis was performed using the Shapiro-Wilk and Levene's tests. Intergroup comparisons were conducted using ANOVA with Tukey's honestly significant difference (HSD) post-hoc tests. Categorical data were analyzed using chi-square tests at p<0.05.  Results: There was a statistically significant difference in the mean number of microcracks after canal preparation among the groups (p = 0.02). A statistically significant increase in crack formation was observed in the OneShape group compared to both the OneCurve group (p < 0.001) and the 2Shape group (p < 0.001). 

Conclusion: During canal preparation, rotary files can lead to the development of dentinal microcracks. OneShape rotary files caused a higher incidence of microcracks than the 2Shape and OneCurve files.

Objective(s): Periodontal pathologies, specifically gingivitis and periodontitis, are posited to exert influence on systemic health states, encompassing pregnancy outcomes. While prior investigations have explored the relationship between periodontal disease and adverse pregnancy outcomes (APOs), including premature birth, low birth weight, and preterm low birth weight, as well as preeclampsia, the correlation with pregnancy termination remains equivocal. The present systematic review and meta-analysis aimed to elucidate the potential association between periodontal disease and diverse manifestations of pregnancy loss. Methods: A thorough review of the literature was performed using PubMed, Scopus, Web of Science, and Google Scholar identified studies on the link between periodontal disease and pregnancy loss, focusing on those meeting criteria that documented the disease in pregnant women and its association with pregnancy loss. To quantitatively synthesize the existing evidence, meta-analytic techniques utilizing Stata/MP 17.0 software were employed. The strength of the relationships between variables was determined through the computation of odds ratios (OR) and their corresponding 95% confidence intervals (CI). Results: A review of 649 studies identified 14 for qualitative synthesis and 5 for meta-analysis. Qualitative findings on the link between periodontal disease and pregnancy loss were inconsistent, with some studies showing a significant association, while others did not. The ORs also exhibited substantial heterogeneity. Additionally, a limited number of studies suggested a potential, albeit marginally significant, inverse correlation between periodontal treatment and pregnancy loss. A meta-analysis of cohort studies found a significant link between periodontal disease and higher pregnancy loss risk (OR = 2.878, 95% CI: 1.158–4.599), while case-control studies showed no significant association (OR = 2.459, 95% CI: 0.270–4.648). Conclusion: Considering the modifiable nature of periodontal disease, the incorporation of dental interventions within preconception and antenatal healthcare protocols may serve as a strategy to mitigate pregnancy loss risk.

Objectives: Dental implants have a high success rate for patients without teeth. However, complications can occur, particularly those related to mechanical issues such as abutment screw fractures. This case report presents an unusual incident of repeated abutment screw fracture during the impression and prosthesis fabrication stages which can be considered the first reported case of screw fracture during the prosthetic fabrication, while it usually presents years after delivery. Case: A 65-year-old female patient presented with repeated fractures of the abutment screws during prosthetics procedures. The initial tightening of the abutment to 32 N caused the fracture, and subsequent analysis revealed defects in the internal surface of the patient's fixture that correlated with the abutment screw fractures. In a conservative management approach, transitioning to a lower torque abutment setting (20 N) was successful without complications. Conclusion: This case highlighted the critical importance of examining the internal structure of dental implants during complication management. The implant's internal surface defects indicate a potential relationship between incorrect insertion torque and mechanical failures.