Page 36 - Peri-implant health: the effect of implant design and surgical procedure on bone and soft tissue stability
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                                CHAPTER 3
bone loss, mean PD, and mean BoP. Based on studies reporting on skewness and distributions it could be expected that data, most commonly, are not normally distributed. This is caused by outliers, which could lead to large standard deviations, rather caused by chance than population. Therefore, the standard deviations on population level are not used in weighing of studies. The variability between studies is more reduced due to the lesser effect of outliers on the mean compared to the effect on the standard deviation and the amount of studies. Therefore, the Pearson correlation coefficients calculated, chosen as measure for a linear relationship between measures, are exploratory and could only be descriptively interpreted in conjunction with the graphical representations. If papers mentioned multiple case definitions, the one with the smallest bone loss threshold was applied in the correlation analysis. Papers with incomplete data reporting were not used for these analyses. In addition, the proportion of implants with bone loss above 1, 2, and 3 mm was estimated based on reported means and standard deviations. If the paper gave a frequency distribution for bone loss, the outcome of the frequency distribution was compared with the calculated proportion of implants with bone loss above 2 mm. Descriptive statistics were performed using MatLab R2015b version (8.6.0.267246; The MathWorks, Inc., Natick, MA, USA).
■ RESULTS
Selection and data reporting
The search yielded 4.173 papers whereof 255 publications were selected for full article reading. At last, 41 fulfilled the inclusion criteria, and the extracted data are summarized in Table 1. The peri‐implantitis case definitions applied in the respective articles are illustrated in Table 2. In total, 41 articles, 21 prospective and 20 retrospective, report on 56 treatment groups. They represent in total 4,198 patients initially treated with 9,657 implants of various brands and with a variety of treatment protocols. A total of 6,246 implants were retrospectively analyzed, and 3,411 implants were prospectively analyzed. Table 3 shows the number of papers and their respective reported parameters.
Survival rate and follow‐up time
Thirty‐eight of the 41 papers reported on survival rate in 49 treatment groups. The overall weighted mean survival rate was 96.9% (89.5%–100%) and 97.2% and 96.2% for retrospective and prospective studies, respectively. In 39 and
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