Comparisons Of Radiological Protocols With Analyzing Trabecular Bone Remodeling Peri-implant Under Various Loading Conditions

Purpose: The aim of the study was to construct the animal model with immediate dental implant placement and different loading protocols,using different radiographic methods to analysis the peri-implant bone remodeling and compare the diagnostic accuracy of CBCT with the other radiological techniques.Materials and methods: 24 implants were immediately placed in the bilateral mandibular premolar and 1st molar areas of 4 beagle dogs and received one of five treatment protocols: immediate loading for 3 months（IL3）,immediate loading for 6 months（IL6）,delayed loading for 3 months（DL3）,delayed loading for 6 months（DL6）and unloading（UL）.After 9 months,all specimens were imaged with CBCT,Micro-CT and intra-oral radiography,analyzed the distribution characteristics of trabecular structures using digital processing software.Results: There were statistically significant differences（p<0.05）of trabecular factors in different loading protocols.IL6 groups had obviously higher values than DL6 or UL for BV/TV,Tb.Th and lower for BS/BV,Po（tot）.Results showed highly significant correlations（r: 0.76-0.99,p<0.001）between Micro-CT and CBCT,in the same with utilizing intra-oral radiography and CBCT for evaluation about bone loss values（r=0.88,p<0.001）.The values of peri-implant bone defects on different loading protocols were not significantly different between buccal,lingual,mesial and distal alveolar bone（p>0.05）.After 3 months of implant placement,bone loss was the most（1.78mm）,while the lessened value was the least（0.11mm）from 6^th month to 9^th month.There were statistically significant differences（p<0.05）between all of the trabecular parameters in the different anatomic regions around implants.Conclusion: High resolution CBCT could quantify peri-implant trabecular morphology,the precision parameters could be used as evaluation criteria on clinical postoperative bone remodeling.Peri-implant trabecular bone structure in three-dimensional areas might be changed regularly.It was valuable for bone remodeling to receive the immediate loading protocol such as to improve bone quality and quantity,especially for a longer time of loading.With the extension of time,peri-implant bone remodeling was gradually stabilized.