Abstract: Objective: To evaluate the clinical effects of micro-ultrasonic removing necrotic tissue on caries. Methods: Thirty patients with dentinal caries were randomly divided into two groups. The experiment group was excavated with ultrasonic tips and the control group with handpieces. The sensitivity of pain, dentin debris after lesions removal, and time consumption were compared. Results: All patients of the experiment group felt painless or minor aches while only 53.3% patients of the control group had the same feeling. There was significant difference between two groups (P<0.05).The dentin debris of micro-ultrasonic group was significantly less than that of handpieces group (P<0.01).The time consumption was also statistically different (P<0.01). Conclusion: The micro-ultrasonic technology is an excellent method to relieve pain and improve the cleanliness of the caries.

Key words: Micro-ultrasonic , Caries removal , Pain , Dentin debris, Time consumption