The Experimental Research Of Two-generation Dental Implants On Development Of The Peri-implantitis

Background and Objectives:Peri-implantitis is one of the common complication of implant prosthesis, which often brings about the failure of dental implants for bone absorption and progressive periodontal packet forming. There are many factors affecting the phenomenon such as physical factors, planting surgical trauma factors, microbiology factors, biomechanics factors, surface structure and so on. The purposes of this study is to investigate the effect on BLB â…  generation and â…¢ generation dental implants of surface modification and surface structure in the progression of experimental peri-implantitis, providing direct theoretical ground to increase the long-term success rate of dental implants.METHODS:Six adult dogs meeting the experiment requirements were picked out. Implants of BLB â…  and BLB â…¢ generation, with each group12, were randomly implanted into the extraction fosses of the bilateral mandibular premolar areas of six dogs. After three month, secondary operation was performed while the abutments were installed. Then two weeks later, animal model of experimental peri-implantitis was established by binding silk threads around the neck of the implants in experimental sides, whereas no disposal in control sides. Peri-implant probing depth (PPD) and radiographies were assessed every other week during the following8weeks. Last step, tissue slices dyed with methylene blue were prepared for histology observation after animals were sacrificed in order to measure vertical bone loss (VBL) and horizontal bone loss (HBL) level.RESULTS:(1)All BLB â…  and â…¢ generation dental implants presented good osseointegration in three months post-operation.(2)Baseline period, the conditions about â…  and â…¢ generation dental implants were roughly the same, including general examination of clinical and radiographic examination;Two weeks later, the gingiva in experimental sides showed slightly swollen, the mean probing depth of â…¢ generation dental implant was deeper than â… , radiographic examination showed the results were close to each other, all controls were normal;Four weeks later, the inflammatory reaction in the experimental sides of two generation dental implants was obvious, the periodontal pocket depth in â…¢ generation was significantly deepened than that of â… ,radiographic examination showed the degree of bone absorption in â…¢ generation was apparent than that of â… , part gingiva had a mild inflammation in control sides;Six weeks later, part experimental gingiva of â…¢ generation fell back to the neck and due to bone loss and gum retreat PPD decreased dramatically the craterlike bone loss around the implants in â…¢ generation was clearly deepened than that of â…  generation by radiographic examination, all control sides made no developments;Two weeks until silk thread removed, the status of soft tissue was gradually improved, there were no significant changes in all control sides. (3) Means of VBL of BLB â…¢ implants was greater than the BLB â…  implants through histology observation (P<0.05), however, no statistic significant difference was found about HBL of different implants (P>0.05)CONCLUSIONS:(1) The level of inflammation is different if surface modification and Surface structure are dissimilar;(2) Surface modification and structure of BLB dental implants act a significant role in the progression of experimental peri-implantitis and BLBâ…¢ implants showed worse consequences than BLBI implants.