Date Published: January 29, 2019
Publisher: Public Library of Science
Author(s): Mani Alikhani, Mona Alikhani, Sarah Alansari, Abdullah Almansour, Mohammad A. Hamidaddin, Edmund Khoo, Jose A. Lopez, Jeanne M. Nervina, Joo Y. Nho, Serafim M. Oliveira, Chinapa Sangsuwon, Cristina C. Teixeira, Subburaman Mohan.
Vibration, in the form of high frequency acceleration (HFA), stimulates alveolar bone formation under physiologic conditions and during healing after dental extractions. It is not known if HFA has an anabolic effect on osteoporotic alveolar bone. Our objective is to determine if HFA has a regenerative effect on osteoporotic alveolar bone.
Adult female Sprague-Dawley rats were divided into five groups: 1) Ovariectomized Group (OVX), 2) Sham-OVX Group that received surgery without ovariectomy, 3) OVX-HFA Group that was ovariectomized and treated daily with HFA, 4) OVX+Static Force Group that was ovariectomized and received the same force as HFA, but without vibration, and 5) Control Group that did not receive any treatment. All animals were fed a low mineral diet for 3 months. Osteoporosis was confirmed by micro-CT of the fifth lumbar vertebra and femoral head. HFA was applied to the maxillary first molar for 5 minutes/day for 28 and 56 days. Maxillae were collected for micro-CT, histology, fluorescent microscopy, protein and RNA analysis, and three-point bending mechanical testing.
Micro-CT analysis revealed significant alveolar bone osteoporosis in the OVX group. Vibration restored the quality and quantity of alveolar bone to levels similar to the Sham-OVX group. Animals exposed to HFA demonstrated higher osteoblast activity and lower osteoclast activity. Osteogenic transcription factors (RUNX2, Foxo1, Osterix and Wnt signaling factors) were upregulated following vibration, while RANKL/RANK and Sclerostin were downregulated. HFA did not affect serum TRAcP-5b or CTx-1 levels. The osteogenic effect was highest at the point of HFA application and extended along the hemimaxillae this effect did not cross to the contra-lateral side.
Local application of vibration generated gradients of increased anabolic metabolism and decreased catabolic metabolism in alveolar bone of osteoporotic rats. Our findings suggest that HFA could be a predictable treatment for diminished alveolar bone levels in osteoporosis patients.
Osteoporosis is a silent and progressive disease that is characterized by reduced bone mineral density, altered protein composition and continuous deterioration of bone microarchitecture . Osteoporosis can occur in both women and men; however, it is well documented that women are more often diagnosed with osteoporosis compared to men, primarily due to the sudden decline in estrogen during menopause .
The current study builds on our previous work demonstrating that local application of vibration in the form of low magnitude load but high frequency acceleration (frequency of 120 Hz, acceleration of 0.3 g and loading of 10 με) significantly increases bone density in healthy alveolar bone and maintains the alveolar bone level after extraction [21, 22]. The effect of increasing acceleration and frequency is not linear, and after a certain level, increasing the frequency does not increase the osteogenic effects .