دراسة تأثر استعمال العدسات المكبرة في جودة تحضير التيجان المنجزة من قبل طلاب طب الأسنان

Abstract EN

Background & Aim: This controlled laboratory evaluation experiment aimed to study the effect of using magnifying loupes on the convergence angle and iatrogenic damage to adjacent tooth surfaces during full crown preparations by Damascus University dental students.

Materials and Methods: The research sample consisted of 40 volunteering students from a group of third-year students at Faculty of Dentistry at Damascus University, using Non-probability sampling method.

Each student prepared an acrylic first upper molar held on a gypsum model layed on phantom heads in three different ways: A using a magnifying loupe, B unaided vision, C using magnifying loupe only while finishing the preparation.

The magnification system used in this study is binocular magnifying loupe which provides 3.5x magnification (ALKASHTO company).

Digital scanning was performed for each model separately to obtain identical 3D images of the prepared teeth and then faciolingual and mesiodistal convergence angles were measured for each tooth.

The degree of damage to adjacent teeth was evaluated using analytic rubric for crown preparations.

Results: The mean of total occlusal convergence angle TOC in the three groups was as follows: in group A 25.3°, in group B 25.6° and in group C 28.35°.

There was no significant difference between groups A and B and a significant increase in the value of TOC in group C showed when repeated-measures ANOVA test was conducted.

No statistically significant difference was found regarding the damage of the second premolars adjacent to the prepared first molar (P =0.2), also no statistically significant increase of damage was found on second molars (p =0.321) between the three groups using Friedman test.

Conclusion: The TOC value increases when the magnifying loupe is used for finishing the preparation.

Magnifying loupes do not decrease damage to adjacent tooth surfaces, as there was no statistically significant difference between the three groups.