In the diseased sites, a mean proximal peri-implant loss of 4.2 ± 1.2 mm and a mean proximal periodontal bone loss of 4.9 ± 0.8 mm MEK inhibitor were observed. The comparative frequency of target bacterial species among peri-implant or periodontal clinical statuses is described in Table 3. The pattern of bacterial frequency observed

was not as expected, i.e. peri-implantitis > mucositis > health. Except for P. intermedia, which did not differ among implant groups (p > 0.05), the additional bacterial species showed higher frequency in peri-implantitis than healthy implant sites (p < 0.05). However, when bacterial frequencies between peri-implantitis and mucositis were compared, similarities (p > 0.05; for C. rectus, A. actinomycetemcomitans, T. forsythia and T. denticola) were more evident than differences this website (p < 0.05; for P. gingivalis and simultaneous presence of red complex species). Considering periodontal samples, a higher frequency of P. intermedia, P. gingivalis, T. forsythia, T. denticola, A. actinomycetemcomitans and simultaneous presence of red complex species was observed in periodontitis group when compared to gingivitis and health (p < 0.05). Contrary to peri-implant findings (peri-implantitis

vs. mucositis) the periodontal bacterial frequency pattern was different between periodontitis and gingivitis. Except for C. rectus (p > 0.05), the other bacteria frequencies were significantly lower in gingivitis than periodontitis (p < 0.05). Finally, Adenosine triphosphate T. forsythia and T. denticola showed the expected pattern of frequency, i.e. periodontitis > gingivitis > health (p < 0.05). A second analysis was performed by comparing the frequency of each bacterial species between similar

periodontal and peri-implant clinical status (healthy peri-implant vs. healthy periodontal sites, mucositis vs. gingivitis and peri-implantitis vs. periodontitis; Fig. 1, Fig. 2 and Fig. 3, respectively). An overall tendency towards higher frequency of bacteria was observed for periodontal sites, especially in periodontitis ones. The frequencies of C. rectus and T. forsythia were higher in periodontal health and gingivitis when compared to peri-implant health and mucositis, respectively ( Fig. 1 and Fig. 2, p < 0.05). On the contrary, when the supportive tissues were involved, dissimilarities were more evident between implants and teeth. The frequencies of P. gingivalis and A. actinomycetemcomitans were similar between periodontitis and peri-implantitis (p > 0.05) while the frequencies of all other bacterial species and red complex species were higher in periodontitis than peri-implantitis ( Fig. 3, p < 0.05). The disequilibrium between host-compatible and pathogenic microorganisms of the oral cavity plays an important role in the ethiopathogenesis of several oral diseases including periodontitis.