Purpose: Piezoelectric surgery is meant to be a gentle method for implant site preparation (ISP). However, the application of load and its influence on heat development over time and effects on soft tissue are unknown. Therefore, this study sought to evaluate heat development in the bone and the duration of the procedure according to load application, as well as preservation of the sinus floor mucosa during piezoelectric ISP. Materials and Methods: One hundred twenty implant sites (6 mm deep × 3 mm wide) were prepared in the calvaria of ex vivo pig heads using piezoelectric surgery. The load applied to the working tip was increased in 100-g intervals up to 1,000 g. The bone temperature was measured, and thermal effects were analyzed histomorphometrically. The duration of each ISP was recorded. Another 12 ISPs were performed at the lateral wall of the maxillary sinus in the vicinity of the sinus floor mucosa, and sites were checked for perforation. Results: Temperature and histologic effects of heat demonstrated a significant positive correlation with the applied load. The duration of ISP was significantly negatively correlated with load application. The maximum temperature generated by piezoelectric surgery was 64.5°C (load of 901 to 1,000 g). At a load of 401 to 500 g, the average temperature was 40.2°C ± 3.3°C, the average thermal damage extended 115.9 ± 16.3 µm beyond the ISP area, and the maximum temperature did not exceed 47°C. The average duration of ISP using this load interval was 45.5 ± 9.4 seconds. Two perforations of the sinus floor mucosa were detected. Conclusions: In the present setting, the applied load during piezoelectric ISP should not exceed 500 g to prevent temperatures above 47°C in the bony implant socket. With a load of 400 to 500 g, ISP took 40 to 50 seconds. Keywords: dental implant, implant site preparation, piezosurgery, sinus floor elevation, thermal tissue alteration, time duration