According to the given definition, the present analysis was based on a total of n = 13 initial to moderate and n = 6 advanced peri-implantitis lesions (n = 19 patients), 10 healthy implant sites (n = 10 patients), as well as 10 teeth with a history of periodontitis (n = 10 out of 19 patients suffering from peri-implantitis).

The analysis of fungal organisms as well as of M. salivarium, V. parvula, S. aureus, P. gingivalis, P. micra, and T. forsythia at peri-implantitis as well as healthy implant and selected tooth sites is presented in Tables 3, 4, and 5.

Fungal organisms were identified in 31.6% (six sites) of the patients and equally distributed between initial to moderate (three sites) and advanced (two sites) peri-implantitis sites. The respective plaque samples were dominated (n = 3) by Candida spp. (i.e., C. albicans and Candida boidinii) and at two sites co-colonized with Penicillium spp. and Rhodotorula laryngis. Paelicomyces spp. (67% homologous), Saccharomycetes (76% homologous), and Cladosporium cladosporioides were identified at three sites (Table 3). The Kendall-Tau-b coefficients failed to reveal any significant correlations between the presence of fungal organisms and the proportions of M. salivarium (−0.26), V. parvula (0.26), S. aureus (0.34), and P. gingivalis (0.09) as well as disease severity (0.26) (P > 0.05, respectively). However, a significant correlation was noted with respect to the proportions of P. micra (−0.42) and T. forsythia (−0.44) (P < 0.05, respectively).

In the selected partially edentulous patients, fungal organisms were identified at four implant sites (Candida dubliniensis and C. cladosporioides), corresponding to a frequency of 40.0% (Table 4). The Kendall-Tau-b coefficients failed to reveal any significant correlations between the presence of fungal organisms and the proportions of M. salivarium (0.38), V. parvula (−0.24), S. aureus (−0.33), and P. gingivalis (−0.51) (P > 0.05, respectively). However, a significant correlation was noted with respect to the proportions of P. micra (0.65) and T. forsythia (0.65) (P < 0.05, respectively).

In the selected partially edentulous patients, fungal organisms were identified at two tooth sites (C. albicans and Fusarium solani), corresponding to a frequency of 20.0% (Table 5).