RETRACTED ARTICLE: Peri-implantitis-associated methanogens: a preliminary report

Souad Belkacemi,Anthony Mazel,Delphine Tardivo,Patrick Tavitian,Grégory Stephan,Giancarlo Bianca,Elodie Terrer,Michel Drancourt,Gérard Aboudharam

doi:10.1038/s41598-018-27862-8

Abstract

Methanogens have already been described in periodontitis but not in peri-implantitis. Thirty peri-implantitis samples and 28 control samples were collected in 28 consenting peri-implantitis patients. PCR-sequencing of the 16S rRNA gene was used as a broad-spectrum screening method and results were further confirmed by real-time quantitative PCR targeting the mcrA genes. Results showed a methanogen community dominated by Methanobrevibacter oralis in 31/58 (51%) samples including 16/28 (57%) control samples and 15/30 (50%) peri-implantitis samples. Methanobrevibacter massiliense was detected in 5/58 (8.6%) samples including 3/28 (1%) control samples and 2/30 (6.7%) peri-implantitis samples. The prevalence of M. oralis or M. massiliense did not significantly differ in peri-implantitis and control samples (exact Fisher test, P = 0.61 and P = 0.67, respectively). Further ponderation of the methanogen load by the real-time quantitative PCR for actin human gene again indicated non-significant difference (Wilcoxon-Mann-Whitney test, P = 0.48 and P = 0.40, respectively). These data show that the prevalence of methanogens does not differ in peri-implantitis lesions and healthy sites, when individuals are their own control. These data do not allow assigning a specific pathogenic role to methanogens in peri-implantitis; methanogens rather are part of the commensal and normal flora of the oral cavity.

Highlights

Peri-implantitis is an inflammatory disease characterized by the destruction of soft and hard tissues and the formation of pockets around osteo-integrated dental implants[1]
We detected the same prevalence of M. oralis and M. massiliensis’s DNA in control samples as in the peri-implantitis samples
Both types of samples originated from the same patient, which means that every patient was his own control. Using this strict methodology and appropriate negative controls which remained negative in all experiments, we observed that the load of both methanogens was not significantly different in the peri-implantitis samples than in the control samples

Summary

Introduction

Peri-implantitis is an inflammatory disease characterized by the destruction of soft and hard tissues and the formation of pockets around osteo-integrated dental implants[1]. Contrasting with metagenomics studies which failed to detect any methanogen in peri-implantitis lesions[2,3], methanogen-targeting molecular investigations detected DNA sequences specific for the methanogens Methanobrevibacter oralis, Methanobrevibacter smithii, Methanomassiliicoccus luminyensis, “Methanobacterium congolense/curvum” and Methanobrevibacter massiliensis in parodontitis pockets[4,5]. M. oralis, an oral cavity inhabitant[6] has been more frequently found in parodontitis pockets[7] in association with anaerobes[8] and its role was analyzed as moderate[7]. Studies relying on the simple, un-quantified molecular detection of sequences leaved unsatisfied the relative role of these methanogens in the pathogenesis of peri-implantitis[9]. We hypothetized that the relative load of methanogens among the total flora in peri-implantitis lesions, would give an indication on the relative role of methanogens in the pathogenesis of peri-implantitis as previously showed for periodontitis[10]

Methods

Results

Conclusion