Evaluation of manual dexterity when using a mirror of dental students and academicians with increasing professional experience.

INTRODUCTION: To evaluate the manual dexterity of dentistry students and academicians when using a mirror according to increasing professional experience. MATERIALS AND METHODS: The study included 72 subjects, grouped according to professional experience 5th year dentistry students (DS) accepted as no experience-academicians with 1-4 years experience (A5L)-academicians with ≥5 years experience (A5M). Direct and indirect visualisation using the mirror was evaluated with the completion times of the O'Connor Finger Dexterity Test. RESULTS: The hand grip strength values of both left and right hand were found to be statistically significantly higher in all the males than in the females (p < .05). The indirect test times (ITT) using the mirror were significantly longer for males than for females (p = .001), and no significant difference was determined between the genders in the direct test times (DTT) (p > .05). For all the study participants, DTT shortened as professional experience increased (p < .05). In addition, the mean values of both DTT (p = .031) and ITT (p = .028) in the DS group were statistically significantly longer than the A5M group. CONCLUSION: With increasing professional experience, manual dexterity was determined to increase, and females were found to be more successful in the direct manual dexterity tests independently of the groups. The statistical significance between the DS and A5M groups, especially in the hand dexterity test with a mirror, shows the importance of experience. The study results demonstrated that professional manual dexterity in dentistry can be developed with increasing practical application.

Qualitative and Quantitative Evaluation of Cytotoxicity of Five Different One-Step Self-Etching Adhesives.

PURPOSE: To qualitatively and quantitatively compare the cytotoxic potentials of five different one-step self-etching adhesives: Prime&Bond One-Select (PB-OS), Optibond All-in-One (OB-AIO), G-Bond (GB), Clearfil Universal Bond (CUB), Single Bond Universal (SBU). MATERIALS AND METHODS: During the first stage of the study, the cytotoxic activities of the test materials were evaluated qualitatively using the direct contact method. In this method, the test materials were placed directly into a monkey kidney epithelial cell culture medium. Reaction zones which occurred in the culture medium were evaluated, in addition to the density and changes in the morphology of the cells. During the second stage, the cytotoxic potential of four different dilutions (1%, 0.1%, 0.01%, 0.001%) of the test materials on L929 rat fibroblast cells was quantitatively evaluated at three different time periods (24 h, 48 h, 72 h) with the MTT tetrazolium-based assay. RESULTS: In the first stage, a zone exceeding 1 cm was observed around or below SBU, CUB, GB and OB-AIO. In PB-OS, the zone borders were approximately 1 cm. In the second stage after the MTT assay, CUB was the most cytotoxic after 24 h, GB and SBU after 48 h, and OB-AIO after 72 h. CONCLUSION: All adhesives tested showed different degrees of cytotoxicity, which statistically significantly increased with dose. Changes were seen related to time.

Monomer release, cell adhesion, and cell viability of indirect restorative materials manufactured with additive, subtractive, and conventional methods.

PURPOSE: The aim of this study was to measure residual monomer, cell adhesion, and cell viability of 3-dimensional printable permanent resin (PR), hybrid ceramic block (HCB), and indirect composite (IC) produced with additive, subtractive, and conventional techniques. METHODS: Five 8 × 8 × 2 mm3 samples of each material were prepared for each experiment. In a 24-h period, monomer release was analyzed with high-performance liquid chromatography, and cell viability and adhesion were evaluated with the water-soluble tetrazolium salt test. Data were analyzed with IBM SPSS Statistics 26.0 statistical software, and results were regarded as significant at α = 0.05. RESULTS: Monomer release (triethylene glycol dimethacrylate, urethane dimethacrylate, and Bisphenol A glycerolate dimethacrylate) was significantly higher in the IC group. Mean cell viability was significantly lower in the HCB group than in the IC group. CONCLUSION: All monomers in the tested materials were released at rates that were below clinical significance. Cell adhesion rates in the groups were similar. Cytotoxic response was classified as minor in the HCB and PR groups and non-cytotoxic in the IC group.

Effect of thickness on the degree of conversion, monomer elution, depth of cure and cytotoxicity of bulk-fill composites.

PURPOSE: Today, bulk-fill composites are used as a single layer with a thickness of up to 4-5 mm. However, is proper polymerization achieved with this increased thickness? METHODS: This study was designed to investigate the effect of thickness on the degree of conversion (DC) (n = 6), the elution of monomers (n = 6), depth of cure (DoC) (n = 10) and cytotoxicity (n = 6) of the bulk-fill composites SDR Flow Plus (SDR), SonicFill2 SingleFill (SF) and ACTIVA Bioactive Restorative (ACT) in comparison to the conventional G-aenial Posterior (GC). Two-way analysis of variance (ANOVA) was used to assess the interaction between materials and surfaces, and one-way ANOVA and Tukey tests were used to compare the degree of conversion, monomer elution and cytotoxicity values (P < 0.05). RESULTS: The highest DC was found at the top surface of SDR, while the lowest DC was found at SF. The V2 mm/V0 mm DoC ratios of the composites except ACTs were appropriate according to the threshold. None of the composites were cytotoxic on day 1. CONCLUSION: In bulk-fill composites, DC decreased and monomer elution increased with increasing depth. The V4 mm/V0 mm ratios of all bulk-fill groups were not appropriate. Additionally, only ACTs had a cell viability of <70% on day 7.