抄録
Low-intensity pulsed ultrasound stimulation (LIPUS) is used in orthopedics as a supplementary therapy to promote the healing of pathological and traumatic fractures, and has also been used in dental implant surgery. Little research exists on the effects of ultrasound on maxillary sinus augmentation, and the mechanisms involved in this process remain unclear. The purpose of the present study was to determine the optimal frequency for enhancing bone regeneration in sinus augmentation by measuring cell proliferation via bromodeoxyuridine (BrdU) analysis in a rabbit model. Forty male rabbits underwent bilateral sinus augmentation in the nasal bone. LIPUS was applied to the experimental sites at two different frequencies (1 and 3 MHz) daily for 1, 2, 4 and 8 weeks. Each histological area of the experimental and control sites was divided into an upper and lower portion from the parietal region to a depth of 5 mm. Immunoreactive nucleated cells were counted by BrdU analysis in each of the three measured areas (1 × 1 mm squares) in the experimental and control sites. The labeling index was defined as the number of BrdU-labeled nuclei divided by the total number of nuclei and was expressed as a percentage. At 1 and 2 weeks, the experimental sites in the 1 MHz group exhibited a significantly higher labeling index than the control sites in both the upper and lower portions. At 1, 2, 4 and 8 weeks, no differences were observed in the upper and lower portions between the experimental and control sites in the 3 MHz group. In conclusion, our results suggest that LIPUS enhances cell proliferation in relation to newly formed bone at 1 week following maxillary sinus augmentation; this effect is greater at a frequency of 1 MHz than at 3 MHz.
