Radiological Method to evaluate Alveolar Bone Regeneration - Chacma Baboon

Objective: The objective was to evaluate a radiological method to measure in vitro alveolar bone regeneration. This particular method is simple, inexpensive and time saving because the equipment is available in the everyday dental practise. Methods: In order to acquire a standardized x-ray image of each quadrant of the oral cavity at different time points, an apparatus consisting of a #21 mandible disposable impression tray was constructed from a XPC-DS Digital Position System, aluminium step wedge, digital x-ray censor, Rinn apparatus and Lab Putty. Three alveolar bone biopsies were taken of each quadrant using a trephine bur from five healthy male chacma baboons (Papio ursinus). The standardized biopsies were 3mm in diameter, 3mm deep and approximately 2mm apart. The standardized x-ray images, using the constructed apparatus, were taken pre-operative, directly post-operative and again after three weeks and six weeks. The results from these images were analysed. A histogram of a computer software programme was used after the grey scale was standardised. Results: The average grey scale value on the histogram of the centre selected biopsy area was compared between images obtained pre-operatively, direct post-operatively, and at three and six weeks postoperatively. The average value for the three biopsies per quadrant was calculated for each of the four images. The averages were expressed as percentages of pre-operative density (normal bone). The results indicated an increase of 6.7 ± -5.1 – 25.3% in bone density after three weeks and 12.4 ± -2.3 – 26.9% after six weeks. Conclusion: The developed radiological method of a standardized grey scale was used to accurately determine bone density, on a computerised histogram. It provided comparative bone density values during the regeneration process of alveolar bone. Although the results were obtained on baboons, it may be extrapolated to humans because of the similarities in bone regeneration.