Effect of deflection loupes on cavity preparation quality and ergonomics

The new deflection loupes are very different from traditional loupes in terms of optics design. They enable the user to look straight ahead while operating on the patient, therefore eliminating the head tilt. This study evaluated cavity preparation quality (class II cavity), procedure time, and ergonomics of general dentistry residents using different types of magnification (naked eye, traditional loupe and deflection loupe). This study used randomized group allocation with fixed sequential design. Thirty general dentistry residents performed class II cavity preparations on plastic right mandibular first molars mounted in manikin using three types of magnification: naked eye, traditional loupe and deflection loupe. The posture was evaluated using the modified Posture Assessment Instrument (PAI). The cavity preparation quality scores, procedure time, posture scores were compared between groups using the Friedman test and Dunn’s tests with Bonferroni correction for pairwise comparisons. Best cavity preparation quality was achieved by using deflection loupe (deflection loupe 79.9 ± 13.0 vs. naked eye 62.8 ± 6.7, p < 0.001;deflection loupe 79.9 ± 13.0 vs. traditional loupe 71.5 ± 9.9, p = 0.007). The procedure time of deflection loupe group was longer than the traditional loupe group (493.2 ± 190.8s vs. 333.6 ± 128.0s, p = 0.024). Deflection loupe group had better overall posture scores (naked eye 8.80 ± 0.81 vs. deflection loupe 7.47 ± 0.9, p < 0.001; traditional loupe 8.60 ± 0.86 vs. deflection loupe 7.47 ± 0.90, p = 0.002) and neck posture scores (deflection loupe 2.57 ± 0.68 vs. naked eye 3.87 ± 0.35, p < 0.001; deflection loupe 2.57 ± 0.68 vs. traditional loupe deflection loupe 3.50 ± 0.57, p < 0.001) . The findings of this study suggest that deflection loupes may offer ergonomic and quality advantages over the naked eye and traditional loupes in the context of cavity preparation. However, the prolonged procedure time observed with deflection loupes indicates a potential learning curve or slower initial adaptation.