Abstract Objective This study aims to assess and compare the influence of hydroxyapatite (HA) and tricalcium phosphate (TCP) nanoparticles on a commercially available epoxy resinbased sealer, focusing on porosity and push-out bond strength. Materials and Methods This work was classified into a control group and two experimental groups. In each experimental group, the sealer was mixed with 2.5 wt.% of HA and TCP nanoparticles. Thirty extracted single-rooted teeth were utilized. After sectioning the crowns, the remaining roots of 15 teeth were used, up to 40 to 0.06, using a K3 rotary system. Smear layers were removed with 3 mL of 17% EDTA applied for 60 seconds. Then, the canals were irrigated with 3 mL of 2.25% NaOCl and 5 mL of distilled water. The strength of push-out bonds was tested via an Instron universal testing machine on a 2 mm section acquired from obturated canals. Data were assessed using one-way ANOVA and post hoc tests at a significance level of p < 0.05. Results A nonsignificant difference (p > 0.05) was evident when the three groups were crosschecked in terms of void volume and bond strength. Micro-CT evaluations revealed the lowest volume of voids to be 0.1152 mm3 (2.69%) for the HA group compared with the control group 0.1818 mm3 (3.9%) and the TCP group 0.2194 mm3 (4.33%). Mean bond strength values were 4.18 ± 1.77 MPa for group 1 (control), 4.19 ± 1.54 MPa for group 2 (HA 2.5%) and 3.76 ± 1.95 MPa for group 3 (TCP 2.5%). Groups 1 and 3 showed both cohesive and a mixed type of failure, while group 2 showed adhesive and a mixed type of bond failure. Conclusion Within the limitations of the study, incorporation of 2.5 wt% HA and TCP nanoparticles into AH Plus did not significantly affect the percentage volume of voids and the bond strength negatively.

Abstract Objective Genetic and environmental factors have important roles in the development of periodontitis. We aimed to assess the relation of vitamin D receptor (VDR) ApaI and TaqI polymorphisms and the susceptibility of periodontitis in Saudi population in Makkah region. Materials and Methods In total, 86 unrelated patients with moderate-to-severe periodontitis and 86 controls were enrolled in this study. Evaluation of the periodontal state was performed by using plaque index, bleeding on probing, probing depth, and attachment loss. Extraction of genomic DNA from peripheral blood and genotyping of VDR gene ApaI G/T (rs7975232) and TaqI T/C (rs731236) polymorphisms were performed by utilizing polymerase chain reaction and restriction digestion. Results There were statistically significant differences between both groups regarding the mean bleeding on probing, mean probing depth, mean plaque index, and the mean attachment level (p < 0.001) indicating that the matching based on the investigated groups was adequate. The examined populations were in Hardy-Weinberg equilibrium. Analysis of the genotype and allele frequencies of both VDR ApaI and TaqI single nucleotide polymorphisms revealed that they were statistically indifferent between the control group and the periodontitis subjects (p> 0.05). Conclusion These results suggested that VDR ApaI and TaqI polymorphisms might not be related to the susceptibility of periodontal disease in the Saudi subjects in Makkah region.

Abstract Objective The effect of polymerization time and resin shade on the depth of cure (DOC) of two nano-hybrid resin composites (Filtek Z250 XT and IPS Empress Direct) was evaluated and compared. Materials and Methods Sixty specimens were prepared from two shades (A1 and A3) of the resin composites. The specimens were allocated into two groups that were further divided into three subgroups depending on the polymerization time (20, 40, and 60 sec; n = 5). After that, the DOC was evaluated by calculating the polymerized part of the specimen’s thickness to the nearest (0.01 mm) using a high-accuracy micrometer. Each specimen was measured three times, and the corresponding mean reading (in mm) was divided by two to obtain the DOC. The data were analyzed using SPSS software, version 20. Descriptive statistics followed by three-way analysis of variance was applied. Multiple comparisons were made using Scheffe post hoc tests (α = 0.05). Results Filtek Z250 XT-A1-60sec presented with the greatest DOC (7.42 ± 0.47 mm), and the lowest DOC was obtained with IPS Empress-A3-20sec (2.31 ± 0.21 mm). The mean DOC of Filtek Z250 XT and IPS Empress Direct resin composites were 6.18 mm and 3.59 mm, respectively. Statistically significant (p < 0.05) difference was observed between the resin composites. The interaction between independent factors, namely composites, resin shade, and polymerization time, revealed that interaction between them contributed significantly to the DOC (p ≤0.05). However, the interaction between resin shade and the polymerization time was insignificant (p = 0.148). Conclusion Filtek Z250 XT demonstrated greater DOC than IPS Empress Direct resin composite. An increase in polymerization time significantly enhanced the DOC of the resin composites irrespective of the resin shade. Regardless of the resin composite tested, DOC was lower for darker shades (A3).

Abstract Objectives The aim of this study was to assess the knowledge, attitude, and practices of ergonomics among dental graduates in Karachi. Materials and Methods A descriptive cross-sectional study was conducted at Altamash Institute of Dental Medicine from December 2019 to April 2020. The study was performed among 174 dental graduates (house officers) in Karachi, using a modified, validated, closed-ended questionnaire. For statistical analysis, SPSS software (version 21) was used for descriptive statistics such as percentages and frequencies. The tests applied were independent t-test and Pearson’s correlation to compare and check the correlation between the variables. The p-value used was ≤ 0.05. Results Among 200 dental graduates, only 174 responses were analyzed in SPSS version 21. Females (78.2%) were more in number than males (21.8%), with most of them aged >23 years (59.1%). Of the study population, 78.7% graduates worked 4 to 6 hours per day, and more than half of the graduates (58%) did not do physical exercise outside work. Furthermore, we found that the majority of responders had a fair knowledge of ergonomic principles, where a total of 134 (77%) dental graduates had a positive attitude towards its implementation, however this was not reflected in their practices as 128 (73.6%) graduates has poor practices related to ergonomics. It was also found that knowledge and practices of ergonomics had a weak but significant correlation (r = 0.263, p = 0.001). Moreover, males were more positive about implementing and practicing ergonomics then females with a significant association (p = 0.001). Conclusions A majority of the dental graduates (house officers) in this present study had a reasonable knowledge of ergonomics and its principles also showed positivity but an only small number of them practiced dental ergonomics. This study recommends the need for including dental ergonomics in the academic curriculum of clinical years of both dental undergraduate and postgraduate studies and also conducts workshops to develop faculty to reinforce its importance.