Ultrasonic versus drills implant site preparation: a histologic analysis in bovine ribs.

Ultrasonic surgery is a recently developed system for cutting bone with microvibrations. The aim of the current study was a histologic comparison between conventional drills versus ultrasonic surgery devices in implant bed preparation.Ten bovine ribs were used, and a total of 100 perforations were randomly performed: half (n = 50) (group A) of the perforations were done through conventional drills using a single cylindrical bur (Bone System, Milan, Italy), 13 mm in height and 2 mm in width at a speed of 400 rpm, and the other half (n = 50) (group B) using an ultrasonic device (Surgysonic; Esacrom, Imola Italy), mounted with a diamond-coated cylindrical tip. After implant sites' preparation, the ribs were immediately stored in 10\% buffered formalin and processed to obtain thin ground sections.At higher magnification, microcracks at the interface were detected. In group A, they were numerous and showed a thickness and depth ranging from 20 to 120 μm and from 500 to 1000 μm, respectively. In group B, very few or no microcracks were present. Statistically significant differences were found in the microcracks density in the cortical bone but not in the cancellous bone.The findings from this study suggest that ultrasonic implant site preparation showed a higher performance in terms of accuracy and uniformity of the osteotomy cut, compared with conventional rotary instruments. Further studies should be conducted to understand whether a smooth, congruent implant bed able to retain fine bone structures may affect the early phases of bone healing and therefore improve osseointegration.