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Evaluation of intraoral optical scanning accuracy for fine structure reconstruction and occlusal records of inlay/onlay preparations.

AIM
This study aimed to determine the impact of different degrees of salivary contamination and variations in occlusal force during intraoral scanning of inlay and onlay cavities on the accuracy of fine structure reconstruction and occlusal records.


MATERIAL AND METHODS
Digital data of inlay/onlay models, collected using an intraoral scanner, were divided into 40 groups according to the restoration type (onlay or inlay), salivary contamination level (none, completely dry; mild, moist but not visually apparent; moderate, half-filled cavity; severe, filled-up cavity), and simulated occlusal force (0, 2, 4, 6, or 8 kg). The acquired 120 datasets were used to measure the average interocclusal space and cavity buccolingual internal angle.


RESULTS
Salivary contamination and occlusal force affected the occlusal contact (p < 0.001), but the restoration type did not (p > 0.05). We found an interaction between inlay type (p < 0.001), but not occlusal force (p > 0.05) and salivary contamination. Salivary contamination also affected the fine structure accuracy (p < 0.001), but the restoration type did not (p > 0.05), and no interaction between the two factors was found (p > 0.05). The difference in the measured internal angle increased with the increase in salivary contamination.


CONCLUSIONS
Intraoral optical scanning of inlay/onlay preparations was reliable for recording occlusal contact but showed uncertainty in cavity fine structure reconstruction when moderate or severe salivary contamination was present in the cavity. 21 Nevertheless, a moist cavity surface with no visually apparent salivary contamination is acceptable.