Evaluation of the effect of different minimally invasive access cavity preparations on discoloration in lower and upper first molars by spectrophotometric analysis method

In this study, the effect of different minimally invasive access cavity designs prepared to the upper and lower molars on discoloration was evaluated by spectrophotometric analysis method. 40 lower molars and 40 upper molars without any caries/restorations were included. Upper molars were randomly divided into 4 main groups (n=10), the lower molars were randomly divided into 4 main groups (n=10). Under DOM, traditional, conservative, ultra-conservative and truss access cavities were opened. After determining the working length, the root canals were prepared with Reciproc R25. 5.25%NaOCl-17%EDTA-5.25%NaOCl were used in the final irrigation. The irrigation activation procedure was performed with #20 Irrisafe ultrasonic tip. After the canals were dried with paper points, they were filled with R25 gutta percha using a single cone technique. AH Plus was used. Gutta percha was cut at the cementoenamel junction. The tooth was restored with A2 composite. Color measurements were performed using the Vita Easyshade V spectrophotometer in accordance with the standards of Commission International de I‟Eclairage at 6 different time periods; before, after and on days 1, 7, 30 and 60. Color measurements were repeated three times from the same point by the same operator under white light by placing the tip of the spectrophotometer on the previously made composite frame on the vestibule surface of the teeth. L*, a* and b* values were recorded and ΔE values were calculated by taking the average. The clinically perceptible threshold of color change was accepted as 3.3 units. The obtained data were analyzed statistically. Clinically perceptible color change (ΔE˃3.3) was observed in the tested groups at various time. When different access cavities were compared to the maxillary molars, it was found that more discoloration occurred at 1 month after the traditional access cavity was opened. No statistically significant difference was found in the other tested groups.