Comparative Evaluation of Vertical and Lateral Gingival Displacement Produced by Mechanical and Chemical Retraction Systems through Digital Impressions using Intraoral Scanner - An in-Vivo Study

Background : Gingival retraction is crucial for impression making in fixed prosthodontics. This invivo study aimed at comparing the gingival retraction in vertical and lateral axes produced by mechanical and chemical retraction systems through digital impressions using intraoral scanner. Materials and Methods: This in vivo, experimental study included 15 subjects,in which further 3 sample groups were allotted making the sample size 45. The mean vertical and lateral gingival displacement done by mechanical and chemical methods was measured at five points of maxillary anterior teeth after preparation on digital impression files made through direct intraoral scanning. Comparison of the mean values without retraction and with different retraction systems were done. The results were analyzed using the One-Way ANOVA, unpaired/independent t test, The Shapiro–Wilk test and Levene’s test. Results : The displacement cord, showed mean vertical displacement to be 0.75 mm and the lateral displacement 1.13 mm. For the retraction paste, the resultant mean vertical displacement was calculated to be 0.68 mm and the lateral displacement 0.67 mm. For vertical displacement, no significant differences were found between the cord and the paste. But statistically significant results were seen for the lateral displacement between the same groups. Conclusion: The cord/mechanical system showed a greater amount of displacement than the cordless/chemical system. Intraoral scanning was found to be an effective means of measuring gingival retraction