Please cite this article as follows: Ranjbar Omidi B, Karimi Yeganeh P, Oveisi S, Farahmandpour N. Comparison of micro-shear bond strength of resin cement to zirconia with different surface treatments using Universal Adhesive and zirconia primer. AbstractIntroduction: Increased demand for metal free fixed partial denture in recent years led to the developing of all ceramic material with excellent mechanical properties. One of the most popular all ceramic is zirconia which shows poor bonding properties. Recently, universal primer contains of silane and phosphate monomer for bond to zirconia have been introduced. The aim of this study is determination of the best method for bonding to zirconia based on the selection of the correct primer, suitable adhesive and best surface pretreatment. Methods: In this in vitro experimental study 16 sintered-zirconia blocks prepared in dimension of (18×6×2 mm) by CAD/CAM technology. Sample cleansed by ultrasonic device contain of 96% ethanol in 6 minutes, after air-drying, based on surface treatment randomly divided into 4 groups which each group divided into 2 sub-groups based on the use of a primer or universal bond: (1) no treatment: (a) cement + zirconia primer, (b) cement + universal bond. (2) Alumina pretreatment: (a) cement + zirconia primer, (b) cement + universal bond. (3) Cojet sand pretreatment: (a) cement + zirconia primer, (b) cement + universal bond. (4) laser pretreatment (a) cement + zirconia primer, (b) cement + universal bond. Composite disc prepared with condensation of composite resin in Tygon tube with integral diminution of 0.7 mm which cured for 40 sconds. Universal bond or zirconia primmer apply on the surface of the zirconia samples then cemented to composite disks by Panavia F2 according manufacture instructions. Microshear bond strength determined with universal testing machine. Failure mode assessed under stereomicroscope. Selected sample based on surface treatment evaluated under SEM. Data were analyzed using one-way analysis of variance (ANOVA).Results: Comparison of the 4 surface treatment groups revealed a significant difference and the highest bond belonged to Cojet and the lowest one to laser group. Conclusion: It seems that Universal Adhesive can to be considered as an alternative to bond to zirconia but the Cojet method is still required.

No abstract

Background and Aim: Common causes of dental discoloration include trauma, drugs, genetic defects, decay, and age. In order to correct discoloration of pulpless teeth, internal bleaching is recommended. The aim of this study was to compare microleakage of resin modified glass ionomer and OrthoMTA used as an intraorifice barrier in non-vital bleaching. Materials and Methods: In this experimental study, 36 extracted mandibular premolars were selected and randomly divided into two experimental (n = 16) and two control groups (n = 2). 2mm of OrthoMTA and RMGI cements were placed as intraorifice barriers in the experimental groups. Subsequently, we placed a mixture of sodium perborate and 30% hydrogen peroxide as internal bleaching material into the canal and replaced it every three days. Leakage was measured using pH diffusion method by a digital PH meter. Data were statistically analyzed by using T-independent test and repeated measures and variance analysis (P<0.05). Results: The pH value of the negative control group was as same as the PH of normal saline while the PH value of positive control group was significantly higher than those of other groups. PH values of Ortho MTA and RMGI at the baseline and on the first, sixth and ninth day did not show significant differences with one another, while microleakage of OrthoMTA group was significantly lower on the third day. Conclusion: In general, OrthoMTA had less leakage than RMGI but both materials can be used as suitable barriers for internal tooth bleaching.

BackgroundTooth decay is one of the most common chronic diseases among children worldwide. Stress and body mass index are also amongst the arguable risk factors which will affect people considerably. They include biological (hormones and blood sugar), socio-economic, and environmental factors and also lifestyle. In the present study, the relationship between tooth decay with stress and BMI in children was therefore investigated.Materials and methodsThis was a cross-sectional study of a descriptive-analytical type. A total of 350 students who were referred to the clinic of the faculty of dentistry at Qazvin University of Medical Sciences during 2021–2022 were selected through convenience sampling method to participate in the study. First, the students underwent a dental examination after being measured on their height and weight. Then, two questionnaires; namely, demographic information and Children's Stress Symptom Scale (CSSS) of Scherer and Ryan-Wenger were completed by the children's parents through self-reporting. The collected data were analyzed using SPSS software version 23 and then descriptive statistics and logistic regression were applied.ResultsThe mean BMI of the participating students was in the normal range. The prevalence of tooth decay among participants was 76.9% (269 people). The mean and standard deviation of stress scores was 6.85 ± 4.01 out of 26, which was at a low level. Also, the mean and standard deviation of the BMI were 22.78 ± 5.28, which was within the normal range. The results of the logistic regression showed that the variables of “father's level of education,” “family's economic status,” “the experience of the toothache during the past year,” “the oral health status,” “the frequency of tooth brushing,” “flossing,” “stress,” and “BMI” were influential factors in tooth decay (P &lt;0.05).ConclusionStudents who had improper BMI, more stress, less educated fathers, families with poor economic status, the experience of toothache within the past year, poor oral health status, and those who used toothbrushes and floss to a minimal degree suffered more tooth decay. Therefore, it is necessary that we pay more attention to these students in designing and implementing educational programs to prevent tooth decay.

No abstract