Influence of knowledge on Brazilian student's perception of life and clinical classes during COVID-19

BACKGROUND

The current pandemic associated with SARS-CoV-2 has negatively influenced several activities, including teaching in Operative Dentistry. The aim of this study was to evaluate the influence of knowledge in Operative Dentistry on undergraduate students' perception related to personal life and return to clinical practices classes during pandemic.

MATERIALS AND METHODS

The present research was a cross-sectional, observational, and qualitative survey. The 16-item based questionnaire was sent to undergraduate students in 2020, which were divided into two groups, according to the Operative Dentistry knowledge: G1-not started clinical practice; G2-already started or completed clinical practice. Questions were focused on the impact of the pandemic in relation to their personal lives and return to clinical practice classes. Chi-square association test was performed using the SigmaPlot 12.0 software (P ≤ 0.05).

RESULTS

The response rate was 55.5% for G1 and 44.4% for G2. Regarding the questions related to personal life, G1 demonstrated higher percentages of fear of contracting the virus during theoretical classes. Same observations were found when students answered about their fear of contracting coronavirus during the clinical practice classes. However, G2 presented the highest agreement responses for the preparedness feeling to return to theoretical classroom, clinical practice classes, and the possibility of applying online learning.

CONCLUSIONS

In general, students' knowledge had little influence on perception of personal life. However, students who have more knowledge in operative dentistry presented more security about returning to clinical classes.

Use of auxiliary devices during retreatment of direct resin composite veneers

The removal of direct composite veneers, when the retreatment is necessary, represents a challenge to the clinician, since the healthy dental structure must be preserved. Thus, the aim of this study was to compare the accuracy provided by different auxiliary devices during retreatment of direct composite veneers. Seventy-five bovine teeth were prepared for direct composite veneers, scanned (T1), and restored. Specimens were divided into 5 groups for retreatment: conventional high-speed handpiece without auxiliary device (WD); high-speed handpiece with a white LED (WL); high-speed handpiece with an UV light (UL); electric motor and multiplier 1/5 handpiece (EM); and conventional high-speed handpiece using magnifying loupe (ML). After retreatments, other scanning was performed (T2). Changes on dental wear or composite residues areas, as well as, the average between wear and presence of residues were measured. Data were submitted to Kruskal-Wallis and Dunn’s post-test (p≤ 0.05). There were greater areas of wear for ML, being statistically superior to WD and EM groups. The ML presented smaller residues areas, being statistically lower than the WD and EM groups. Regarding the average between wear and the presence of resin residues, additional wear occurred after re-preparation, regardless of the group. Magnifying loupe promoted greater areas of wear and smaller areas of resin residues than conventional high-speed handpiece and electric motor. Both techniques using light accessories did not differ from other ones.

Influence of different types of light curing units and photoinitiators in microhardness and color of composite resins after immersion in wine

Abstract Objective: the aim of this study to evaluate the microhardness and color change (?E) of composite resins, light cured with different LEDs, submitted to staining drink. Materials and Methods: Two composite resins with lucerin-TPO (Tetric N-Ceram/ Vit-l-escence) and camphorquinone (Filtek Z350) were select. Specimens (n=120) were prepared. Then were photopolymerized with LED of singlewave or polywave. Microhardness and color evaluations were performed before and after chalanges. Data were evaluated by two-way ANOVA, Tukey's test (p?0,05). Results: No statistically significant difference between the two generations of LEDs was found for microhardness data. Regarding the ?E, statistical difference between the two LEDs was observed for Tetric N- Ceram and Filtek Z350. Conclusion: Compostion of composites appears to have more influence on analyses than the type of LEDs.