This study aimed to compare the surface roughness, hardness, and flexure strength of interim indirect resin restorations fabricated with CAD-CAM (CC), 3D printing (3D), and conventional techniques (CV). Twenty disk (3 mm × Ø10 mm) and ten bar specimens (25 × 2 × 2 mm) were fabricated for the CC, 3D, and CV groups, to be used for surface roughness, micro-hardness, and flexural strength testing using standardized protocol. Three indentations for Vickers micro-hardness (VHN) were performed on each disk and an average was identified for each specimen. Surface micro-roughness (Ra) was calculated in micrometers (μm) using a 3D optical non-contact surface microscope. A three-point bending test with a universal testing machine was utilized for assessing flexural strength. The load was applied at a crosshead speed of 3 mm/min over a distance of 25 mm until fracture. Means and standard deviations were compared using ANOVA and post hoc Tukey–Kramer tests, and a p-value of ≤0.05 was considered statistically significant. Ra was significantly different among the study groups (p < 0.05). Surface roughness among the CC and CV groups was statistically comparable (p > 0.05). However, 3D showed significantly higher Ra compared to CC and CV samples (p < 0.05). Micro-hardness was significantly higher in 3D samples (p < 0.05) compared to CC and CV specimens. In addition, CC and CV showed comparable micro-hardness (p > 0.05). A significant difference in flexural strength was observed among the study groups (p < 0.05). CC and 3D showed comparable strength outcomes (p > 0.05), although CV specimens showed significantly lower (p < 0.05) strength compared to CC and 3D samples. The 3D-printed provisional restorative resins showed flexural strength and micro-hardness comparable to CAD-CAM fabricated specimens, and surface micro-roughness for printed specimens was considerably higher compared to CAD-CAM and conventional fabrication techniques.

The present study aimed to formulate an experimental adhesive (EA) and reinforce it with 5 wt.% titanium dioxide (TiO2) or zirconium oxide (ZrO2) to yield 5% TiO2 and 5% ZrO2 adhesives, respectively, and then analyze the impact of this reinforcement on various mechanical properties of the adhesives. The EA contained a blend of monomers such as bisphenol A glycol dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA), and ethyl 4-dimethylamino benzoate and camphorquinone. The EA included ethyl 4-dimethylamino benzoate and camphorquinone photo-initiators, and diphenyliodonium hexafluorophosphate (DPIHP) was also included to act as an electron initiator. The TiO2 and ZrO2 nanoparticles were incorporated into the EA post-synthesis. To characterize the filler nanoparticles, scanning electron microscopy (SEM) and line-energy dispersive X-ray (EDX) spectroscopy were performed. The adhesives were characterized by analyzing their rheological properties, shear-bond strength (SBS), and interfacial failure types. Further, the resin–dentin interface was also analyzed via SEM. The TiO2 nanoparticles were spherically shaped on the SEM micrographs, while the ZrO2 nanoparticles were seen as non-uniformly shaped agglomerates. The EDX mapping demonstrated the presence of Ti and oxygen for TiO2 and Zr and oxygen for the ZrO2 nanoparticles. Both 5% TiO2 and 5% ZrO2 adhesives revealed decreased viscosity as compared with the EA. The 5% TiO2 adhesive demonstrated higher SBS values for both non-thermocycled (NTC) and thermocycled samples (NTC: 25.35 ± 1.53, TC: 23.89 ± 1.95 MPa), followed by the 5% ZrO2 adhesive group (NTC: 23.10 ± 2.22, TC: 20.72 ± 1.32 MPa). The bulk of the failures (>70%) were of adhesive type in all groups. The SEM analysis of the resin–dentin interface revealed the development of a hybrid layer and resin tags (of variable depth) for the EA and 5% TiO2 groups. However, for the 5% ZrO2 group, the hybrid layer and resin tag establishment appeared compromised. Reinforcement of the EA with TiO2 or ZrO2 caused an increase in the adhesive’s SBS (with the 5% TiO2 group demonstrating the highest values) in comparison with the EA (without nanoparticles). However, both nanoparticle-containing adhesives revealed decreased viscosity compared with the EA (without nanoparticles). Further studies investigating the impact of diverse filler concentrations on the properties of adhesives are suggested.

The quality of communication between dentists and dental technicians in Riyadh can sometimes be inadequate, and governmental laboratories have a lower level of communication.

Objective: To assess gynecologists’ knowledge of the association between female sex hormones and periodontal health. Methods: A cross-sectional study was conducted on gynecologists at various hospitals across the five areas of Riyadh, Saudi Arabia. Data was collected using a self-administered questionnaire. The questionnaire was divided into three parts, covering the participants’ demographics, their knowledge about the association between periodontal health and female sex hormones, and the participants’ practices regarding medications prescribed to treat their patients. Results: During the study period, 203 gynecologists agreed to take part in this study. The overall mean percentage of knowledge regarding the association between periodontal health and female sex hormones among participants was 66.8%. Only 53.0% of participants reported that periodontal disease is a risk factor for preterm deliveries; 50.0% indicated that gingival changes could be induced by the long-term use of oral contraceptives and 35.1% agreed that periodontal health checkups must be regularly carried out for pregnant women. Conclusions: Although the overall knowledge level of the gynecologists about periodontal health and female sex hormones was satisfactory, they showed an unsatisfactory level of knowledge about the association between periodontal disease and another aspect of women's health across their adult lifespan, such as the importance of a regular periodontal health checkup for pregnant women. Increased awareness amongst gynecologists may improve their level of knowledge about the effect and importance of periodontal health for women.

Objectives. To explore and compare undergraduate dental students' views and preferences towards various teaching strategies. Methods. A questionnaire was developed and distributed to 345 male and female undergraduate dental students from the two major dental schools in Riyadh (College of Dentistry, King Saud University [KSU], and Riyadh Colleges of Dentistry and Pharmacy [RCsDP]). Students' preferences for various components of the lecture courses were investigated. Descriptive and crosstab analyses were used to compare the students' preferences for each school and between genders; the chi-square test was used to measure the significance level ( = 0.05). Results. The majority of students preferred having the lecture schedule announced in advance. Females preferred morning lectures, whereas male students preferred afternoon lectures. Nearly half of the students thought that attending lectures should be mandatory; most of them were from KSU. Most of the students reported preferring a PowerPoint presentation lecture. The students, particularly female students, also preferred to receive lecture handouts and study materials before the session and to have practical demonstrations after the lecture. Conclusion. Teachers should consider students' opinions when constructing courses because this feedback would have a positive impact on the teaching environment and students' performance.