[Effects of loupes and microscope on laminate veneer preparation]

To assess and compare the effects of loupes and microscope on laminate veneer preparation of the first practitioner from the aspects of efficiency, quality and accuracy of preparation, and preference.

Twenty young prosthodontists from the Department of Prosthodontics, Peking University School and Hospital of Stomatology were recruited into this study, which was prospective, single blind, self-control trials. The participants had no experience of using dental magnification devices. They prepared laminate veneers in the artificial dental model, under routine visual field (control group), 2.5× headwear loupes (loupes group), and 8× operating microscope (microscopic group) by turning. The time for tooth preparation was recorded. Thereafter, subjective assessments of efficiency, quality of preparation and preference were performed by themselves using visual analogue score (VAS). Expert assessments of quality and accuracy of preparation were performed by two professors using stereomicroscope and digital technique respectively.

In terms of efficiency, the subjective scores for the control group, loupes group and microscopic group were 7.15±1.73, 8.10±0.91 and 5.40±2.04, respectively. There was significant difference between the loupes group and microscopic group (P<0.05). The time of tooth preparation for the control group, loupes group and microscopic group was (430.10±163.04) s, (393.90±157.27) s and (441.95±164.18) s, respectively. There was significant difference between the loupes group and microscopic group (P<0.05). The loupes group was more efficient than the microscopic group. In terms of the quality of preparations, the subjective scores for the control group, loupes group and microscopic group were 6.55±2.09, 7.85±0.99 and 6.25±1.77, respectively. There was significant difference between the loupes group and microscopic group (P<0.05). The expert evaluations for the control group, loupes group and microscopic group were 12.20±1.67, 12.50±1.70 and 11.35±2.60, respectively. There was significant difference between the loupes group and microscopic group (P<0.05). The loupes group had higher quality than the microscopic group. In terms of the accuracy of preparations, the control group, loupes group and microscopic group of incisal 1/3 were (0.107±0.097) mm, (0.142±0.118) mm and (0.123±0.087) mm, respectively, of middle 1/3 were (0.128±0.073) mm, (0.113±0.105) mm and (0.125±0.077) mm, respectively, and of cervical 1/3 were (0.075±0.054) mm, (0.068±0.044) mm and (0.058±0.047) mm, respectively. There was no significant difference among the three groups (P>0.05). In terms of the preference, the subjective scores for the control group, loupes group and microscopic group were 6.55±2.31, 8.60±1.10 and 5.80±2.07, respectively. There was significant difference between the loupes group and microscopic group (P<0.05). The participants had the highest preference for loupes.

For the first practitioners, loupes is better than microscope for laminate veneer preparation.