Georgios Charalampakis

Clinical and microbiological characteristics of peri‐implantitis cases: a retrospective multicentre study

OBJECTIVES The aim of this study was to follow patient cases retrospectively in a longitudinal manner from the time of implant placement to the time they were diagnosed with peri-implant disease, and to identify associated clinical and microbiological features of peri-implant disease. MATERIAL AND METHODS A total of 281 patient cases were chosen from the archives of the Oral Microbiological Diagnostic Laboratory, Gothenburg, Sweden, based on bacterial samples taken from diseased implants. A form was designed and filled in separately for each case including data on patient, implant and disease profile. RESULTS Most cases were severe peri-implantitis cases (91.4%). In 41.3% of the patients, peri-implantitis was developed early, already after having implants in function less than 4 years. The type of implant surface was significantly associated with the time in years implants were in function, before disease was developed (P < 0.05). The microbiological results by both culture and checkerboard analysis, although failed to fully correspond to the severity of the disease in terms of magnitude, proved to show that peri-implantitis is a polymicrobial anaerobic infection with increased number of AGNB (aerobic Gram-negative bacilli) in 18.6% of the patients. CONCLUSIONS Peri-implantitis is a biological complication of implants in function that poses a threat to their long-term survival. It may develop earlier around implants with rough surfaces and it may represent a true infection. Microbiological sampling methods should be improved and uniformed so as to fully unveil the microbiological profile of the disease.

A follow‐up study of peri‐implantitis cases after treatment

AIM The aim of this retrospective study was to follow patient cases in a longitudinal manner after peri-implantitis treatment. MATERIALS AND METHODS Two hundred and eighty-one patient cases were selected consecutively from the archives of the Oral Microbiological Diagnostic Laboratory, Gothenburg, Sweden based on microbial analysis of bacterial samples taken from diseased implants. It was feasible to follow-up 245 patients after treatment for a period ranging from 9 months to 13 years. RESULTS In 54.7% of the patients it was not feasible to arrest progression of peri-implantitis. Smoking and smoking dose were found to be significantly correlated to failure of peri-implantitis treatment (p<0.05). Early disease development was also significantly associated with failure (p<0.05). Bone plasty in conjunction to antibiotics during surgery was significantly associated with arrested lesions (p<0.05). In a multiple regression model disease development was the only independent variable to significantly predict the likelihood of treatment success. CONCLUSIONS Peri-implant health may not be easy to establish, especially in cases that develop disease early. Homogenous treatment protocols rather than empirical treatment attempts should be adopted.

Autopathogenic correlation of periodontitis and rheumatoid arthritis

Recently, a number of studies have pointed to a potential relationship between periodontitis (PO) and RA and vice versa. Both diseases are characterized by chronic inflammation, osseous destruction, damage of the supporting soft tissues, similar cellular immune responses and common immunogenetic findings. Although a definite, methodological report associating these diseases is missing from the literature, it is possible that both diseases share a common aetiopathogenic background. This background includes the post-translation modification citrullination, which guides the conversion of the amino acid arginine to citrulline in certain self-proteins, generating neo-epitope structures. This results in reduced self-tolerance, development of autoimmunity and the production of ACPAs. The current hypothesis suggests that certain oral bacteria induce the citrullination of proteins under the action of the enzyme peptidyl arginine deiminase (PAD), which exists in both Porphyromonas gingivalis and inflammatory cells. Antibodies against citrullinated proteins and peptides constitute a common serological finding in both RA and PO. The aim of this review is to map the immunological and serological profiles of PO, and to unveil the parameters that connect PO with the appearance of RA at clinical, prognostic and pathogenetic levels. Until now, there have been no reports sufficiently mapping the immunological profile of PO and defining its aetiopathogenic connection with RA, although a similarity between the immunological profile of PO and RA is highly expected.

Microbiome of peri-implant infections: Lessons from conventional, molecular and metagenomic analyses

Osseointegrated dental implants are now a well-established treatment option in the armament of restorative dentistry. These technologically advanced devices are designed to functionally and esthetically replace missing teeth. Despite the revolutionary advances that implants have incurred, they have also provided the oral cavity with new artificial surfaces prone to the formation of oral biofilms, similarly to the hard tissue surfaces of natural teeth. Biofilm formation on the implant surface can trigger the inflammatory destruction of the peri-implant tissue, in what is known as peri-implantitis. The mixed microbial flora of peri-implant infections resembles that of periodontal infections, with some notable differences. These are likely to expand with the ever increasing application of metagenomics and metatrascriptomics in the analysis of oral ecology. This review presents the wealth of knowledge we have gained from microbiological methods used in the characterization of peri-implant microflora and sheds light over potential new benefits, as well as limitations, of the new sequencing technology in our understanding of peri-implant disease pathogenesis.

Peri-Implant Infections of Oral Biofilm Etiology

Biofilms are complex microbial communities that grow on various surfaces in nature. The oral micobiota tend to form polymicrobial biofilms, particularly on the hard mineralized surfaces of teeth, which may impact on oral health and disease. They can cause inflammation of the adjacent tooth-supporting (periodontal) tissues, leading to destructive periodontal disease and tooth loss. The emergence of osseointegrated dental implants as a restorative treatment option for replacing missing teeth has also brought along new artificial surfaces within the oral cavity, on which oral bacteria can form biofilms. As in the case of natural teeth, biofilms on implant surfaces may also trigger infection and cause inflammatory destruction of the peri-implant tissue (i.e. peri-implantitis). While there are strong similarities in the composition of the mixed microbial flora between periodontal and peri-implant infections, there are also a few distinctive differences. The immunological events underlying the pathogenesis of peri-implant infections are qualitatively similar, yet more extensive, compared to periodontal infections, resulting in a faster progression of tissue destruction. This chapter summarizes the current knowledge on the microbiology and immunology of peri-implant infections, including findings from the peri-implant crevicular fluid, the inflammatory exudate of the peri-implant tissue. Moreover, it discusses the diagnosis and current approaches for the treatment of oral infections.

Adjunctive Systemic and Local Antimicrobial Therapy in the Surgical Treatment of Peri-implantitis A Randomized Controlled Clinical Trial

The aim of the present randomized controlled clinical trial was to investigate the adjunctive effect of systemic antibiotics and the local use of chlorhexidine for implant surface decontamination in the surgical treatment of peri-implantitis. One hundred patients with severe peri-implantitis were recruited. Surgical therapy was performed with or without adjunctive systemic antibiotics or the local use of chlorhexidine for implant surface decontamination. Treatment outcomes were evaluated at 1 y. A binary logistic regression analysis was used to identify factors influencing the probability of treatment success, that is, probing pocket depth ≤5 mm, absence of bleeding/suppuration on probing, and no additional bone loss. Treatment success was obtained in 45% of all implants but was higher in implants with a nonmodified surface (79%) than those with a modified surface (34%). The local use of chlorhexidine had no overall effect on treatment outcomes. While adjunctive systemic antibiotics had no impact on treatment success at implants with a nonmodified surface, a positive effect on treatment success was observed at implants with a modified surface. The likelihood for treatment success using adjunctive systemic antibiotics in patients with implants with a modified surface, however, was low. As the effect of adjunctive systemic antibiotics depended on implant surface characteristics, recommendations for their use in the surgical treatment of peri-implantitis should be based on careful assessments of the targeted implant (ClinicalTrials.gov NCT01857804).

Effect of cleansing of biofilm formed on titanium discs

OBJECTIVES To study the combined effect of mechanical and chemical cleansing on a 4-day biofilm grown intra-orally on titanium discs with different surface characteristics. MATERIAL AND METHODS Twenty subjects used a splint with two metal plates in the upper jaw. Each plate was placed in the premolar-molar region and carried four titanium discs with four different surface characteristics (OsseoSpeed(™), TiOblast(™), experimental and turned surface). After 4 days of biofilm growth, the discs were cleaned mechanically and chemically with saline or chlorhexidine. Following cleansing, microbial samples were obtained and analysed by culture. The titanium discs were processed for scanning electron microscope (SEM) analysis. The experiment was repeated 3 days later using delmopinol or a mixture of essential oils during cleansing. RESULTS The combination of mechanical and chemical cleansing was ineffective in complete biofilm removal from all four titanium discs. The microbiological analysis did not reveal any statistically significant differences between surface types or between cleaning agents regarding logarithmic mean counts of CFU for specific bacteria, aerobes, anaerobes or the TVC. Aerobes were more numerous than anaerobes on all surface types. The SEM analysis disclosed that the remaining biofilm on moderately rough surfaces (OsseoSpeed(™), TiOblast(™) and experimental) was complex and firmly attached, while the biofilm on turned surface had a pattern of spread bacteria forming less clusters. CONCLUSIONS Cleansing may call for prolonged time of chemomechanical debridement and/or more effective disinfectants to suppress biofilms on dental implant surfaces.

The effect of the local use of chlorhexidine in surgical treatment of experimental peri‐implantitis in dogs

AIM To evaluate the effect of surgical treatment of experimental peri-implantitis at implants with different surface characteristics using different anti-infective procedures. MATERIAL AND METHODS Four implants with different surface characteristics (A: TiOblast, B: OsseoSpeed, C: AT-I, D: TiUnite) were installed in a randomized order in each side of the mandible in 6 labrador dogs 3 months after tooth extraction. Experimental peri-implantitis was induced 3 months later. Surgical treatment of peri-implantitis was performed. The implants were cleaned with gauze soaked in either saline (control) or chlorhexidine (test). Clinical and radiographical examinations were performed and microbiological samples were taken during a 6-month period after surgery. Biopsies were obtained and prepared for histological analysis. RESULTS Clinical signs of soft tissue inflammation were reduced after surgical therapy in most test and control sites. While the analysis of bone level alterations in radiographs together with histological and microbiological assessments of resolution of peri-implantitis lesions failed to demonstrate statistically significant differences between test and control procedures, the evaluations disclosed significant differences between implant D and implants A, B and C on treatment outcome. CONCLUSION It is suggested that (i) the local use of chlorhexidine has minor influence on treatment outcome, (ii) resolution of peri-implantitis following surgical treatment without the adjunctive use of local and systemic antimicrobial agents is possible and (iii) the results are influenced by implant surface characteristics.

Peptostreptococcus canis sp. nov., isolated from subgingival plaque from canine oral cavity

A polyphasic taxonomic study was performed on two strains of an unknown Gram-positive, asaccharolytic, nonspore-forming, obligately anaerobic coccus-shaped bacterium isolated from oral subgingival plaque of Labrador retriever dogs. Comparative 16S rRNA gene sequencing confirmed that these isolates were highly related to each other and formed a hitherto unknown linage within the clostridial rRNA XI cluster of organisms. Pairwise analysis demonstrated that the novel organism to be most closely related to members of the genus Peptostreptococcus with 16S rDNA gene sequence similarity values between 92.8% and 96.7%, respectively. The G + C DNA base composition was 30.8 mol% and the major cellular fatty acids included iso-C(14:0,) iso-C(16:0), and iso-C(16:0 DMA). Based on biochemical, chemotaxonomic, and phylogenetic evidence it is proposed that the unknown bacterium be classified as a new species, Peptostreptococcus canis sp. nov. The type strain is CCUG 57081(T).