## 4 Discussion  
Overall, our results showed that morse taper implants with an abutment diameter smaller than the implant platform led to a better pattern of clinical and bone parameters, with lower peri-implant bone loss and lower PPD and CAL in T2 DM rehabilitated with implant muco-retained overdentures, with positive modulation of inflammatory mediators compared to the control implants, which consisted of external hexagon implants with a standard connection. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Group** & **0–12 Months** & **12–24 Months** \\ \hline Control & 0.74 \(\pm\) 0.44 Aa & 0.44 \(\pm\) 0.74 Ba \\ \hline Test & 0.50 \(\pm\) 0.31 Ab & 0.07 \(\pm\) 0.15 Bb \\ \hline \hline \(p\)-value & 0.0003 & 0.0229 \\ \hline \hline \end{tabular} Different letters (capital letters horizontally and lowercase letters vertically) indicate statistically significant differences (\(p\leq 0.05\)).  
\end{table} 
Table 6: Annual changes (mean \(\pm\) SD) in the crestal bone level during the study in both groups (mm). Figure 3: Representative images of the buccal, mesial, lingual, and distal bone level measurements. (**A**) Mesial and distal bone level measurement; (**B**) Buccal and lingual bone level measurement. In this trial, dental implants in the test group were based on the platform-switching concept. The idea behind \"platform switching\" is that the trans-mucosal abutment diameter is smaller than the implant shoulder diameter. Implants inserted with this idea have an implant-abutment junction nearer to the center of the implant. This concept led to minimal marginal peri-implant bone loss compared to implants with similar diameters of abutment and implant body, due to the positive effect of platform switching on marginal bone levels [9; 24]. These findings agree with the tomographic outcomes of the present study that detected in the annual bone loss analysis that there was a lower amount of bone loss in the test group both in the first and second years when compared to the control group (\(p<0.05\)). Although data concerning marginal bone loss in diabetic populations has been scarce until now, systematic reviews also support that platform switching has a positive influence on peri-implant marginal bone loss and appears beneficial in limiting bone resorption [10]. Different degrees of peri-implant crestal bone remodeling are influenced by the implant-abutment connection designs after functional loading. [PERSON] et al. [15] demonstrated this in a split-mouth RCT that evaluated 12 dedentulous patients with four customized implants in the mandibular interforaminal zone. The macroscopic design of the implants was the same and used external hexagon or morse-taper connections, and a standardized periapical X-ray evaluation found greater remodeling of the crestal bone with a higher loss around the external hexagon compared to the morse-taper. Considerable impact on peri-implant crestal bone level is related to the implant-abutment connection [25]. Additionally, in an animal study, [PERSON] et al. [26] histologically and histomorphologically evaluated bone resorption around implants, and morse taper presented less bone loss compared to external hexagon. According to [PERSON] et al. [27], periapical radiographs showed significantly greater bone loss in the external hexagon connection than morse taper implants in patients rehabilitated with immediately loaded mandibular overdentures during a 1-year follow-up, in agreement with the data observed in this study. Some authors justify this remodeling according to the zone of stress. Lower concentration and better distribution of stress/strains in the peri-implant bone were observed in finite element analysis evaluating morse taper implant-abutment connections compared to external hexagonal connections [12; 14; 15; 28]. These data agree with the outcomes presented in this study and with previous investigations that related decreased bone loss in implants with morse taper connections compared to other connection types [15; 25; 27].