## 4 Discussion
Among the criteria evaluated, all these studies assessed the absence of increased peri-implant bone loss called \"bone stability\" ([PERSON] et al., 2020) [40], the \"absence of progression of decrease in peri-implant crestal bone level\" ([PERSON] et al.) [36], \"no ongoing bone loss\" ([PERSON] et al.) [38], \"peri-implant bone levels remained stable over time\" ([PERSON] et al.) [45], or \"no further bone loss\" ([PERSON] et al.) [33]. Only one study measured \"bone regeneration\" ([PERSON] et al.) [43]. For the studies that used the survival rate criterion ([PERSON] et al. [34; 35], [PERSON] et al. [37], [PERSON] et al. [42], [PERSON] et al. [46], [PERSON] et al. [39]), it corresponded to implants that were not removed/lost. In our study, 96.7% of the overall treated implants did not have progressive bone loss. Compared with our results, some studies ([PERSON] et al. [34; 35], [PERSON] et al. [36], [PERSON] et al. [39], [PERSON] et al. [44], [PERSON] et al. [43], [PERSON] et al. [45], [PERSON] el al. [42], [PERSON] et al. [40]) described a 100% implant survival rate. These higher results can be explained by the fewer number of implants treated (19, 9, 11, 2, 6, 2, 17, 4, respectively). On the other hand, some studies showed lower results, 70% ([PERSON] et al.) [33], 95.3% ([PERSON] et al.) [32], 90% ([PERSON] et al.) [37], 92.5% ([PERSON] et al.) [38], 87% ([PERSON] et al.) [46], and 87% ([PERSON] et al.) [41], which can be explained by the fact that they did not use the same assessment criteria or the difference could be explained by the lower number of implants, 30 ([PERSON] et al.) [41] and 70 ([PERSON] et al.) [46], compared with our 91 treated implants. A longer follow up of 9 years ([PERSON] et al.) [46] and 2 to 6 years ([PERSON] et al.) [41] could also have an impact on the results. In our study, 96.5% of the included patients did not have progressive bone loss. Compared with our results, [PERSON] et al. [32] showed a patient-level implant survival rate of 95.3% and [PERSON] et al. [41] showed a patient-level \"disease resolution\" of 83%. These lower results could be explained by the fact that they did not use the same evaluation criteria (implant survival rate; bleeding/suppuration on probing and pain on peri-implant palpation, respectively). In our study, a 100% no-marginal-implant bone loss rate was obtained for the reconstructive procedure, whereas this rate was 90% in the study of [PERSON] et al. [32] This lower result could be explained by a difference in the location of the implantoplasty, which they performed only on the supraosseous surface of the implant, whereas we also performed it in the intraosseous part. In our study, a 92.9% of no-marginal-implant bone loss rate was obtained for the flap apicalisation procedure. Some studies showed a 100% implant survival rate ([PERSON] et al. [32], [PERSON] et al. [34,35]] [PERSON] et al. [36] [PERSON] et al. [40]). These higher results could be explained because in our study two implants failed in the respective surgery group and probably because of the higher number of implants treated by [PERSON] et al. (104 implants) than our study (50 implants). Two studies ([PERSON] et al. [46] [PERSON] et al. [41]) showed an implant survival rate of 87%. These lower results could be explained by the longer follow up of 9 years ([PERSON] et al.) [46] or because the use of clinical parameters for establish disease resolution rate ([PERSON] et al., 2019) [41]. In our study, a 98% of no-marginal-implant bone loss rate was obtained for combined procedure which is different from the results obtained by [PERSON] et al. [39] who obtained 100% probably because their follow up was shorter (12 months) than ours. The results obtained in our study should be interpreted with caution due to the short follow-up time (mean \(\approx\) 2 years), and the bias consisted in the duration difference which varies from 12 to 42 months depending on the patient. The efficacy of surgical treatment in combination with implantoplasty of peri-implant lesions in the long term is still unknown.