Background and Aim: When using improper recording materials during the fabrication of dentures, the whole process could be compromised in spite of the precision administered during the rest of the procedure. The aim of this study was to compare the flow of Pars Wax, Azardent, Crystal and Asia Wax with the DENTAL Modelling Wax Detry (Manufactured in Dentsply) according to standard indices of ADA, specification no. 24.Materials and Methods: All flow tests were conducted in accordance with the corresponding ADA specifications. Two samples of each wax (10 mm wide x 6 mm heigh) were prepared. A force of 19.6N (2kg) was applied on each specimen at three different temperatures: 23, 37 and 45°C. The geometric changes were accurately measured with a micrometer and compared to those obtained prior to the tests. The ratios of the dimensions after force application to the initial dimensions were determined. Based on these ratios, wax flows were compared to standard indices. Results: The amount of flow at 23°C and 45°C, obtained for all studied waxes was in accordance with the corresponding standard values, proposed by ADA. However, at 37°C the flow of none of the studied waxes was in the range of the ADA standards.Conclusion: Considering that the tested waxes demonstrated conflicting results at different temperatures when compared with the standard values, further investigation using different batch numbers is suggested.

Background and Aim: The design and manufacture of DENTAL restorations with the help of milling machines has developed at a high speed since their introduction and offers more precision and options. The paradigm shift from traditional techniques to CAD/CAM technology has created a revolutionary change in the methods for fabrication of restorations. Modern milling machines dedicated to DENTAL care are kinematic structures that work in 4 or 5 axis and represent one of the key parts of CAD/CAM. 4-axis and 5-axis machines are guided by the feed angle control and the direction of the milling cutter, which depends on the contact surface between the cutting tool and the block being turned, enabling a higher quality of surface integrity. The purpose of this review article is to investigate the types and applications of milling machines in dentistry. Material and Method: This review study was conducted using the electronic version of articles available in the search engines PubMed and Google Scholar from 2000 to the end of 2024 using the keywords milling machine, CAD/CAM, 5-axis milling machine, 4-axis milling machine. All articles were in English and finally 32 articles were selected and reviewed. Conclusion: Milling machines are available both for DENTAL offices and general DENTAL laboratories and for industrial DENTAL laboratories. These machines increase the precision and quality of DENTAL restorations. Restorations prepared by milling machines provide better results than conventional methods in terms of mechanical strength in chewing and aesthetics.

2Background and Aims: Journal of DENTAL Research is among the dentistry journal with the highest impact factor. This study aimed to map the most important topics for journal editors and readers. Materials and Methods: The world's active research topics in the field of dentistry related to the Journal of DENTAL Research in the last 5 years were extracted from SciMapper's SciTrends. Also, we clustered the most cited papers in that journal to show the most important research topics for the journal editors and readers. Results: We identified and mapped 11 active international research areas in the field of dentistry and related to this journal. Among 146 faculty members of the school of dentistry, 12 had at least one article related to the most active research areas in the journal. In this regard, they had similar articles elated to the 7 clusters out of 13, but their articles are mainly related to the clusters 7 and 19. Among the investigated faculty members, nine had directly collaborated with 21 authors of the mapped clusters. Moreover, 12 faculty members could also connect to the 126 authors with articles in that journal through their scientific collaborators. Conclusion: One way to publish in a top international journal is to know the most active and interesting research areas for the journal editors and readers. About 8% of the school of dentistry faculty members at Tehran University of Medical Sciences had some research related to the Journal of DENTAL Research.

Statement of Problem: DENTAL Unit Water Systems (DUWS) have been demonstrated to be contaminated with biofilms. This biofilm could be a site for growth and colonization of pathologic microorganisms. Purpose: The aim of this research was to measure the Total Cultivable Flora (TCF) in DUWS of Khorasgan DENTAL school and the effect of stabilized chlorine dioxide on its reduction.Materials and Method: In this research, 60 samples of water from high speed turbines, air-water syringes, cavitrons and wash basins were collected. The samples were cultured in agar nutrition media and incubated for 5 days. After the incubation period, colonial counting was done by HPC method. In the next stage, stabilized chlorine dioxide was added in a container for each unit and the samples were taken from air-water syringes, cavitrons and turbine outlets .As for the first stage, after 5 days of culture and incubation, the samples were observed under microscope for counting the bacterial colonies. Kruskal-Walis and Mann-Whitney tests were used for statistical analysis.Results: A high level of bacterial contamination (more than 200 CFU) was observed in high speed turbines, air-water syringes, cavitrons and wash basins. The highest colonial count was observed from cavitron and the lowest from washbasin outlets but the difference was not statistically significant .After using chlorine dioxide, the amount of bacterial colonies was significantly reduced (p <0.05). Conclusion: The amount of bacterial contamination in DUWS of Khorasgan DENTAL school was higher than the accepted level .These bacteria were mainly opportunistic .The addition of an anti-bacterial agent in the DUWS will significantly reduce the bacterial count to an acceptable level.

Aim: This study was designed to assess the level of gram negative bacterial contamination in water supply of DENTAL units used at Shahid Beheshti University at the year 1999.Material and Methods: Water samples were obtained from water syringe lines and high - speed turbine lines of 30 DENTAL units which were initially selected on random manner. All samples were stored in sterile tubes containing 5cc nutrient broth followed by an incubation stage on EMB and MacCankey plates for 48 hours at 37oC. Bacterial colonies were then counted and compared with suggested limit by ADA.Results: Sections of first floor had shown. Psedomonas and staphylococcus contamination were seen in 37.5% of the samples collected form DENTAL units of surgical wards at first floor while 61.5% of the samples of DENTAL units of restorative wards (2nd floor) had staphylococcus contam E.coli and Entrococcus contamination were found in samples of or the/paedo clinic water supply samples in 75% of the cases.Conclusion: there appeared to be a relationship between the increase in the number of microorganisms and water stagnation on the upper floors of the building.

Background and Aim: Metal ceramic restorations are widely used in crowns. The marginal fitness of these artificial crowns is prone to alteration during the firing cycle of porcelain. Gold electroformed metal-ceramic restorations have been introduced as alternatives to conventional metal-ceramic restorations. However little is known about the relationship between procelain firing procedures and marginal adaptation of this type of crown. The aim of the present study was to evaluate the influence of firing procedures on the marginal adaptation of electroformed metal-ceramic crown restoration.Materials & Methods: One steel die was prepared for maxillary molar crowns with deep chamfer finishing line design. Ten standardized gold electroformed copings were fabricated. Marginal discrepancy was measured at four sites along the circumferential margin of each coping (Midbuccal - Midpalatal - Midmesial - Middistal) using SEM (Mag: X400) prior to and after porcelain firing procedure. Data among the 2 different groups (before porcelain firing) were statistically analyzed using the paired t-test (a=0.05) analysis.Results: The marginal discrepancy of the postfiring procedures (21.45±2.27 mm) were significantly greater than those of the prefiring procedures (18.23±1.96 mm) (p<0.002).Conclusion: The porcelain-firing procedures influenced the marginal distortion of electroformed metal-ceramic crown restorations, but the marginal discrepancies for all copings and examined design are clinically acceptable (less than 100 mm).

Background and Aim: An important criterion for success assessment of implant-supported prostheses is marginal fit. Vertical and horizontal discrepancy can result in loosening of the prosthetic screw, crestal bone resorption, peri-implantitis and loss of osseointegration. Despite careful attention to waxing, investing, and casting, marginal discrepancies are inevitable. The aim of this study was to evaluate the marginal gap and overhang in three casting methods with two different alloys in ITI implants.Materials and Methods: In this experimental in vitro study 48 analog abutments were randomly divided into six groups as follows: 1) burn out cap + BegoStar, 2) impression cap + BegoStar, 3) conventional wax up + BegoStar, 4) burn out cap + Verabond2, 5) impression cap + Verabond2, 6) conventional wax up + Verabond2. Waxing was done in 0.7 mm thickness verified by a digital gauge and a putty index was made for all groups. Reamer was used for correction of the finish line after casting in all groups. Castings were seated on analog abutments and embedded in acrylic resin. Specimens were sectioned by isomet instrument and polished and cleaned by ultrasonic cleaner for 10 min. The marginal gap and overextended margins of castings were examined under a Scanning Electron Microscope (SEM) (X200). The mean gap and margin overextension were calculated for each group. Data were analyzed by multivariate analysis and Bonferroni post-hoc test with p<0.05 as the level of significance.Results: No significant difference in gap size was observed among the three casting methods with two alloys (P=0.056). The marginal gap was not different in the studied casting methods (P=0.092). Gold alloy crowns showed lower marginal gaps compared to base metal alloy crowns (P<0.001). No significant difference in overhang size was observed among casting methods with two alloys (P=0.093). Base metal alloy crowns showed less overhang compared to gold alloy crowns (P<0.001). There was a significant correlation between overhang and use of impression cap in base metal alloys (P<0.001).Conclusion: Based on the results of this study, vertical discrepancy of frameworks made with gold alloy were less than those made with base metal alloy. Base metal alloy demonstrated fewer overhangs. Conventional wax up or using burn out caps produced less horizontal discrepancy.

Introduction: The academic setting and the educational process in DENTAL school can be inherently stressful. Therefore, the aim of this study was to investigate the stressors in the educational setting from the perspective of DENTAL students at Yazd DENTAL School. Methods: This descriptive-analytical cross-sectional study was conducted in 2021 among clinical-year DENTAL students at Yazd University of Medical Sciences. Demographic information and stress levels across different areas were gathered through the DENTAL Education Stress Questionnaire. Data were analyzed using SPSS software version 16 with statistical tests including t-tests, analysis of variance (ANOVA), and Pearson’s correlation coefficient all at a significance level of 0. 05. Results: Among the 240 students who participated, 62. 9% were female. The mean total stress score for all students was 80. 17 ± 13. 7 out of 132. Forty percent of students indicated experiencing high stress, 59. 2% reported moderate stress, and merely 0. 8% showed low stress levels. No significant differences were identified in the overall stress score or across domains when analyzing gender, parental education, or year of admission (P > 0. 05). The overall stress score and the academic efficiency domain were significantly reduced in native students (Yazd residents) compared to non-native students (P = 0. 048 and P = 0. 016, respectively). No significant differences were observed in other domains (P > 0. 05). Conclusion: The findings of this study indicate that stress levels in the DENTAL setting was moderate to high among most students, with the clinical education aspects being the primary source of stress. Residency status (native vs. non-native) was the only demographic factor that significantly decreased students’ stress levels.