A Retrospective Study Of Marginal Bone Loss About Single Tooth Implant-supported Restorations In The Posterior Region

Objective:The objective of this study was first to compare two methods about transforming traditional X-ray films to digital images and evaluate the feasibility of judging the bone level around the implant by them, and then to analyze the relationship between marginal bone loss around implants placed in posterior region and age, length of implants, diameter of implants, location of implants, crown-to-root ratio of implant-supported restorations, the history of peri-implantitis. To summarize the important decision making factors when planning the placement of short implants and provide a rational for solving them.Methods: First to transform traditional X-ray films to digital images by Digital Single Lens Reflex and scanner, and then to compare the diversity between 3 different methods by paired t-test. A prospective cohort study design was used. Make sure the patient enrolment criterion, then measure the bone level around the implant on the digital images which were transformed by scanner. All measurements were finished by a software named Digimizer. Data were analyzed with descriptive statistics.Results: Significant difference was not found between 3 methods by paired t-test (P>0.05). The cohort was composed of 188 patients who were followed about 37.4 (SD=8.9; range 12 to 48) months. The mean age was 43.6 (SD=5.6; range 18 to 75). The mean length of implants was 10.4 months. There were 12 (5.4%) implants with restoration fracture and 23 (10.4%) implants with peri-implantitis. No implants failed. The cumulative success rate was 100%. The mean CRR was 1.06 (SD=0.22; range 0.69 to 1.86) with 125 (56.3%) of the implants having a CRR beyond 1.00. The mean CRR of 38 (17.1%) implants which were used for the patients who are beyond 60 years old was 1.19. There was significant difference about the distribution of CRR between these patients and the others (P<0.001). The same result was found between different length of implants (P<0.001). However patient's age, length of implants, diameter of implants, location of implants and CRR of implant-supported restorations did not appear to affect MBL around implants (P>0.05). Significant difference were found regarding MBL in first time interval (P<0.001) and the history of peri-implantitis (P =0.002).Conclusion:â‘ The accuracy of two methods which were used to transform traditional X-ray films to digital images was confirmed.â‘¡Although the CRR of old patients (>60) was significant different with young patients (<60), there was no significant difference were found between CRR and MBL.â‘¢Although there was no significant difference were found about MBL when CRR is beyond 1.5, doctors should be cautious to consider various important decision making factors when make a treatment plan.â‘£The patients who had a history of peri-implantitis lost more bone around implants. They should be recalled more frequently and get more education about the maintenance of implants.