Study Year of publication Type of
patients/sites 		Number of
patients 		Number of
implants/sites 		Outcome
Cosyn et al. [58] 2011 Peri-implant sulcus 8 healthy patients NS Plaque and BOP correlated with sulcular levels of 30/40 species. For 25 species, the detection frequency was at least 75%.
De Bruyn et al. [59] 2013 Peri-implant bone level 12 patients 71 implants 25/40 species in more than 80% of the implants. Large variation in bacterial levels between implants. Fusobacteria, Leptotrichia buccalis, P. micra, V. parvula, and T. forsythia showed the highest levels. Implants with shallow pockets showed significantly lower counts of: A. odontolyticus, C. gracilis, F. nucleatum naviforme, and Leptotrichia buccalis. No significantly different total DNA count between implants with shallow and deep pockets.
Dierens et al. [60] 2013 Peri-implant vs. periodontal health 46 patients NS T. forsythia and V. parvula showed the highest concentrations around implants and teeth, respectively. Significantly more P. gingivalis, P. intermedia, T. forsythia, P. micra and T. denticola around implants. Total DNA count correlated to interproximal bleeding index (r = 0.409) and interproximal probing depth (r = 0.307). No correlations with plaque index or radiographic bone level.
Ebadian et al. [61] 2012 Peri-implant health and disease vs. periodontal health and disease 69 patients
(21 non-periodontitis;
22 chronic periodontitis;
13 non-peri-implantitis;
13 peri-implantitis) 		1 per patient Statistical difference between prevalence of P. intermedia, P. gingivalis, T. forsythia, C. rectus, Prevotella tannerae, T. denticola and P. endonticula in all groups. Higher incidence of all species in periodontitis sites; only 37.5% of species showed higher prevalence in peri-implantitis. Significant difference for T. forsythia, P. intermedia and C. rectus in PI vs. CP; no significant difference between HI and HP.
Persson et al. [62] 2014 Peri-implantitis vs. peri-implant health 213 patients
(166 peri-implantitis;
47 healthy) 		1 implant per patient Higher counts of A.a., C. gracilis, C. rectus, Campylobacter showae, Helicobacter pylori, Haemphilus influenzae, P. gingivalis, S. aureus, S. anaerobius, S. intermedius, S. mitis, T. forsythia, T. denticola and T. socranskii in peri-implantitis. A cluster including T. forsythia and S. aureus are associated with peri-implantitis.
Salvi et al. [63] 2012 Peri-implant mucositis vs. periodontal gingivitis 15 patients 1 per patient and condition No differences in total DNA counts or detection frequency for putative periodontal pathogens between implant and tooth sites. P. gingivalis detected occasionally after 3 weeks of abolished oral hygiene.
Hallström et al. [86] 2012 Peri-implant mucositis 43 patients
(21 control;
22 test [systemic antibiotics]) 		1 per patient No differences between groups.
Tsoukaki et al. [87] 2013 Flapped vs. flapless implants 20 patients
(10 flapped;
10 flapless) 		30 implants
(15 flapped;
15 flapless) 		Significantly higher levels of P. gingivalis and T. forsythia and higher but not significant T. denticola in flapless vs. flapped implants.

NS = not specified; BOP = bleeding on probing; PI = peri-implantitis; CP = chronic periodontitis; HI = healthy implant; HP = healthy periodontium.