Objective:Anxiety towards dental procedures are common difficulties that may be experienced by dental patients all over the world. This study focused on evaluating the dental anxiety frequency and its relationship with age, gender, educational level, and past dental visits among patients attending the outpatient clinics of College of Dentistry, Al Jouf University, Saudi Arabia.Material and Methods:A total of 221 patients, aged 21–50 years were selected for the study. A questionnaire comprising the Modified Dental Anxiety Scale (MDAS) was used to measure the level of dental anxiety. Data was analyzed using SPSS version 20.Results:The mean anxiety score of the 221 patients was 11.39 (SD ± 2.7). Independent t-test showed a significant variation between the age groups with regards to their mean overall anxiety score (P < 0.05), which reduced with increasing age. A significant difference was found by independent t-test in the mean total score between male and female groups and regarding previous dental visit (P < 0.05). Regarding education level, there was no significant difference between the groups (P > 0.05).Conclusion:Younger patients, female, and patients with previous unpleasant dental experience were associated with increased MDAS score.Clinical Significance:The present study was done for better patient management and proper treatment plan development for dentally anxious patients.

Objective: To evaluate the effect of different cement gap on microleakage of PMMA crowns cemented with resin cement. Materials and Methods: Thirty natural human molar teeth were collected, the root of the teeth was sealed with a double layer of varnish for insulation to a level of 1 mm below the preparation margin, and mounted in an acrylic mold. Teeth were prepared through CNC, PMMA crowns fabricated by CAD/CAM. Samples were divided into 3 subgroups according to the cement gap (CG) (n=10): 25µm (CG25), 50µm (CG50), 100µm (CG100). PMMA crowns cemented with Breeze Self-Adhesive Resin Cement. Samples were thermocycled for 5000 cycles between two water baths at 5°C and 55°C with a dwell time of 20 seconds and 10 seconds of transfer time. Samples were immersed in methylene blue dye solution for 24 hours, then sectioned buccolingually. Dye penetration was assessed using a spectromicroscope, and then a score assessment was done for the microleakage. Results: The CG50 group scored the lowest median microleakage score, followed by CG100, and finally, CG25. The CG25 group; showed a statistically significantly higher median microleakage score than CG50 or CG100 groups. Conclusion: The cement gap has an effect on the microleakage of PMMA crowns cemented with self-adhesive resin cement.

Glycidyl azide polymer (GAP) and hydroxyl terminated polybutadiene (HTPB) have been evaluated for use as binder for solid propellants. Characterization of the used prepolymers (GAP & HTPB) by employing the possible means to examine their :,Density (Densimeter) , Characteristic groups and IR spectrum by Fourier transformation infrared (FTIR),Nitrogen content (CHN 240), Viscosity (viscometer) ,Humidity ( using Karl-Fisher) and Milligram equivalent (OH)/ Milligram binder (By Titration) . The effects of various parameters like cross-linking conditions, concentration of crosslinker, and the ratio of isocyanate to hydroxyl functional groups (NCO/OH ratio) on the mechanical properties were studied in detail , by preparation of different cross-linked GAP network and cross-linked HTPB network binder formulations using selected materials, From survey it was observed that GAP based binders have poor mechanical characteristics compared with HTPB binders ,So GAP functionality must be raised by the addition of triol ( trimethylol propane (TMP)) to generate the desired extended polymeric matrix, also using a curing catalyst dibuthyltin dilaurate (DBTDL),to ensure curing completion ,the NCO/OH ratio was varied from 0.7 to 1.5, keeping the crosslinker content at 5% with respect to binder (for GAP only), The GAP based specimens were also prepared with cross-linker content varying from 3-9% by weight with respect to binder, keeping the NCO/OH ratio constant at 1, Stress-strain relation for the prepared samples were measured to evaluate the effect of crosslinker, and the ratio of isocyanate to hydroxyl functional groups (NCO/OH ratio) on the mechanical properties to perform the comparison between them from curing & mechanical behavior point of view . KEY WORDSGlycidyl Azide Polymer (GAP), hydroxyl terminated polybutadiene (HTPB) . mg equivalent (OH), solid propellants. TMP.

Objective: To evaluate the effect of different cement gap on retention of zirconia crowns cemented with resin cement. Materials and methods: Thirty natural human molar teeth were collected and mounted in an acrylic mold. Teeth were prepared through CNC, and then zirconia crowns fabricated by CAD/CAM. Samples were divided into 3 subgroups according to the cement gap (CG) (n=10): 25µm (CG25), 50µm (CG50), 100µm (CG100). Zirconia crowns cemented with Breeze Self-Adhesive Resin Cement. Samples were thermocycled for 5000 cycles between two water baths at 5˚C and 55˚C with a dwell time of 20 seconds and 10 seconds of transfer time. Samples were subjected to tensile test, dislodgment force recorded in MPa. Results: No significant difference was found between mean pull-out bond strength at different cement gaps. Conclusion: The 25 µm cement gap gave the best retention for zirconia restorations.