Implementing magnification during pre‐clinical training: Effects on procedure quality and working posture

Objective: The objective of this study was to evaluate the effects of magnification on the quality of two pre-clinical procedures, class I cavity preparations and composite resin restorations, and to evaluate the working posture. Methods: This was an experimental laboratory study. The response variables were the quality of cavity preparations and Class I restorations as well as the working posture adopted during the execution of these procedures. The independent variables were the magnification system under four levels (unaided visualisation, the use of a simple loupe, the use of a Galilean loupe and the use of a Keplerian loupe) and the artificial teeth treated. Class I cavity preparations and restorations (N = 320) were performed using standardised procedures, and the quality achieved was evaluated using pre-established criteria. Working posture was recorded using digital video cameras and was evaluated using the Compliance Assessment of Dental Ergonomic Posture Requirements (CADEP). A two-factor analysis of variance (ANOVA) and multiple comparison test were performed (α = 0.05). Results: The quality of cavity preparation did not differ significantly amongst the different magnification systems (P = 0.082). Galilean and Keplerian systems had a positive impact on restoration quality only for the left mandibular first molar (P = 0.04). Higher posture scores were observed when Galilean and Keplerian loupes (P = 0.01) were used, regardless of the tooth being treated. Conclusion: The use of Galilean and Keplerian magnification lenses did not affect the quality of the pre-clinical procedures performed whilst improved the scores of ergonomic posture.Department of Social Dentistry São Paulo State University (UNESP) School of DentistryDepartment of Social Dentistry São Paulo State University (UNESP) School of Dentistr