Background The aim of this study was to investigate the mechanical properties and dentin microshear bond strength of a conventional glass ionomer cement (GIC) compared to GIC supplemented with silver nanoparticles (SNPs) at 0.1% and 0.2% (w/w). Material and Methods SNPs were incorporated into a conventional GIC at 0.1% and 0.2% (w/w). The unmodified GIC was used as the control group. Compressive strength, flexural strength, and micro-shear bond strength (µSBS) to dentin were evaluated using a universal testing machine. Surface microhardness was determined using a Vickers microhardness tester. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test. Results GICs containing 0.1% and 0.2% (w/w) SNPs significantly improved compressive strength, surface microhardness, and dentin µSBS compared to the unmodified GIC ( p <0.05). A significant increase in the flexural strength was found for the GIC containing 0.2% (w/w) SNPs ( p <0.05). However, the GIC containing 0.1% (w/w) SNPs did not affect flexural strength. Conclusions GIC supplemented with SNP is a promising material for restoration because of its improved mechanical and bond strength properties. Therefore, it may be suggested for use especially in higher stress-bearing site restorations. Key words: Glass ionomer cement, mechanical properties, micro-shear bond strength, silver nanoparticle.

Aim: The narrowing of the mandible during opening and protrusion movements is defined as median mandibular flexure (MMF). MMF is caused by the attachment of mandibular muscles; therefore, it can be assumed that a greater amount of maximum occlusal force (MOF) may cause more flexion and could affect the survival of dental and implant restorations. The purpose of this study was to evaluate any relationship between MOF and MMF in a sample of adults. Settings and Design: In vivo – comparative study. Materials and Methods: In this descriptive, cross-sectional, nondirectional study, a sample of 90 volunteers were recruited (45 men and 45 women). MOF was measured by applying the strain gauge receptor to the first molar region, and MMF was measured by calculating the variation in the intermolar distance by a digital caliper with an accuracy of 0.01 mm using an impression and resulted in the stone cast during the maximum opening and closed-jaw positions. The body mass index (BMI) also was calculated. Statistical Analysis: Data were analyzed using the SPSS software (version 23) inferential and descriptive statistics, linear regression, and Pearson correlation coefficient. P < 0.05 was considered statistically significant. Results: There was no statistically significant relationship between MOF and MMF ( P = 0.78), but there was a significant association between MOF and BMI ( P < 0.001, r = 0.475) and gender. Conclusion: Although MOF and MMF are both important and effective factors in the success of prosthetic restorations, one cannot be expected by the other and both should be considered in the treatment plan separately.

Objectives Complete cleaning of temporary cement before permanent cementation of cement‐retained implant‐supported prosthesis (CISP) when recementing the crown is critical. This study evaluated the effect of different cleaning methods for removing traces of temporary cement on the final tensile bond force (TBF) of CISP recemented with resin cement. Materials and Methods Seventy computer‐aided design/computer‐aided manufacturing metal implant‐supported copings were prepared and distributed into seven groups (N = 10). Copings of six groups (60 samples) were cemented with temporary cement with eugenol and subjected to 5000 thermocycling. After debonding by a universal testing machine, the internal surfaces of the copings were cleaned using one of the six following methods: 1‐an ultrasonic water bath (UW), 2‐sandblasting, then washing with water (SW), 3‐sandblasting and an ultrasonic water bath (SUW), 4‐an ultrasonic isopropyl alcohol bath (UA), 5‐sandblasting, then washing with isopropyl alcohol (SA) or 6‐sandblasting and an ultrasonic isopropyl alcohol bath (SUA). Then the subjects were subsequently cemented by dual‐cure self‐adhesive resin cement. In the seventh group (control, N = 10), the copings were cemented by dual‐cure self‐adhesive resin cement without the temporization phase. The TBF was tested using a universal testing machine with a cross‐head speed of 1 mm/min. Two‐way analysis of variance (ANOVA) and post‐hoc Tamhane tests were used for statistical analysis at a significance level of α = .05. Results The maximum mean of TBF value was observed in SUA group (845 ± 203 N), and the minimum was observed in the temporary cement group (49 ± 20 N). All groups which were cleaned with isopropyl alcohol showed significantly higher TBF values compared with those cleaned with water. Conclusions Cleaning of the inner surface of metal copings after debonding with sandblasting and isopropyl alcohol results in the highest value of TBF by eliminating the effect of remaining eugenol and removing traces of temporary cements.

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