Microbiota at teeth and implants in partially edentulous patients. A 10-year retrospective study

Metagenomic analysis of healthy and diseased peri-implant microbiome under different periodontal conditions: a cross-sectional study

BACKGROUND

Peri-implantitis is a polybacterial infection that can lead to the failure of dental implant rehabilitation. This study aimed to profile the microbiome of the peri-implant plaque and estimate the effect of periodontitis on it among 40 Chinese participants with dental implant prostheses and presenting with varying peri-implant and periodontal health states.

METHODS

Submucosal plaque samples were collected from four distinct clinical categories based on both their implant and periodontal health status at sampling point. Clinical examinations of dental implant and remaining teeth were carried out. Metagenomic analysis was then performed.

RESULTS

The microbiome of the peri-implantitis sites differed from that of healthy implant sites, both taxonomically and functionally. Moreover, the predominant species in peri-implantitis sites were slightly affected by the presence of periodontitis. T. forsythia, P. gingivalis, T. denticola, and P. endodontalis were consistently associated with peri-implantitis and inflammatory clinical parameters regardless of the presence of periodontitis. Prevotella spp. and P. endodontalis showed significant differences in the peri-implantitis cohorts under different periodontal conditions. The most distinguishing function between diseased and healthy implants is related to flagellar assembly, which plays an important role in epithelial cell invasion.

CONCLUSIONS

The composition of the peri-implant microbiome varied in the diseased and healthy states of implants and is affected by individual periodontal conditions. Based on their correlations with clinical parameters, certain species are associated with disease and healthy implants. Flagellar assembly may play a vital role in the process of peri-implantitis.

Antibacterial Activities of Ag/Cellulose Nanocomposites Derived from Marine Environment Algae against Bacterial Tooth Decay

Dental caries is an infectious oral disease caused by the presence of different bacteria in biofilms. Multidrug resistance (MDR) is a major challenge of dental caries treatment. Swabs were taken from 65 patients with dental caries in Makkah, Saudi Arabia. Swabs were cultivated on mitis salivarius agar and de Man, Rogosa, and Sharpe (MRS) agar. VITEK 2 was used for the identification of isolated bacteria. Antibiotic susceptibility testing of the isolated bacteria was performed using commercial antibiotic disks. Ulva lactuca was used as a reducing agent and cellulose source to create nanocellulose and Ag/cellulose nanocomposites. Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction spectroscopy (XRD) were used to characterize nanocellulose and Ag/cellulose nanocomposites. The results showed that most bacterial isolates were Streptococcus spp., followed by Staphylococcus spp. on mitis salivarius media. Lactobacillus spp. and Corynebacterium group f-1 were the bacterial isolates on de Man, Rogosa, and Sharpe (MRS) media. The antibiotic susceptibility test revealed resistance rates of 77%, 93%, 0, 83%, 79%, and 79% against penicillin G, Augmentin, metronidazole, ampicillin, ciprofloxacin, and cotrimoxazole, respectively. Ag/cellulose nanocomposites and Ag/cellulose nanocomposites with fluoride were the most effective antibacterial agents. The aim of this work was to assess the antibacterial activity of Ag/cellulose nanocomposites with and without fluoride against bacteria isolated from the oral cavities of patients with dental caries. This study demonstrated that Ag/cellulose nanocomposites have antibacterial properties against multidrug-resistant bacteria that cause dental caries.

Microbiota associated with peri-implantitis-A systematic review with meta-analyses

AIM

To answer the following PECO question: "In systemically healthy human subjects (P), which are the differences between peri-implantitis (E) and peri-implant health/mucositis (C) in terms of bacterial presence/count (O)?"

MATERIALS AND METHODS

Cross-sectional studies fulfilling specific inclusion criteria established to answer the PECO question were included. Two review authors independently searched for studies, screened the titles and abstracts, did full-text analysis, extracted the data from the included reports, and performed the risk of bias assessment through an adaptation of the Newcastle/Ottawa tool for cross-sectional studies and of the JBI critical appraisal checklist. In case of disagreement, a third reviewer author took the final decision. Study results were summarized using random effects meta-analyses.

RESULTS

A total of 12 studies were included, involving 1233 participants and 1513 implants. Peri-implantitis was associated with the presence of S. epidermidis (Odds ratio, OR = 10.28 [95% Confidence interval, CI: 1.26-83.98]), F. nucleatum (OR = 7.83 [95% CI: 2.24-27.36]), T. denticola (OR = 6.11 [95% CI: 2.72-13.76]), T. forsythia (OR = 4.25 [95% CI: 1.71-10.57]), P. intermedia (OR = 3.79 [95% CI: 1.07-13.35]), and P. gingivalis (OR = 2.46 [95% CI: 1.21-5.00]). Conversely, the presence of A. actinomycetemcomitans (OR = 3.82 [95% CI: 0.59-24.68]), S. aureus (OR = 1.05 [95% CI: 0.06-17.08]), and C. rectus (OR = 1.48 [95% CI: 0.69-3.17]) was not associated with peri-implantitis.

CONCLUSIONS

Peri-implantitis is associated with the presence of S. epidermidis and specific periodontopathogens (P. gingivalis, T. forsythia, T. denticola, F. nucleatum, and P. intermedia). (CRD42021254589).

The Impact of Smoking on Peri-implant Microbiota: A Systematic Review

OBJECTIVES

Peri-implantitis is associated with bacterial plaque biofilms and with patients who have a history of periodontitis. Smoking is a risk factor for periodontitis, but the relationship between smoking and peri-implantitis is unclear. The aim of this systematic review was to assess evidence ascertaining the relationship between smoking and peri-implant microbiota.

DATA SOURCES

An electronic search was conducted in the MEDLINE/PubMed, Embase and Scopus® databases in duplicate up to January 2023 without language restrictions. Studies were considered eligible for inclusion if they involved evaluation of the peri-implant microbiota of smokers and nonsmokers. Methodological quality was assessed with the adapted Newcastle-Ottawa scale.

STUDY SELECTION

Fourteen studies were identified for inclusion in the present study, and 85.7% of the studies were defined as medium to high methodological quality. Overall, the evidence presented in this review was limited to medium to high methodological quality. The data indicates that significantly higher frequencies of anaerobic pathogens are detectable in healthy peri-implant tissues of smokers. A lower diversity of microbiota was observed in healthy peri-implant sites of smokers. In the transition from clinically healthy to a diseased status, smoking shaped a reduced peri-implant microbiota by depleting commensal and enriching pathogenic species.

CONCLUSIONS

The composition of peri-implant microbiota may be influenced by smoking. More studies are needed to determine the impact of smoking on peri-implant microbiota.

CLINICAL SIGNIFICANCE

In the transition from clinically healthy to a diseased status, smoking shaped a reduced peri-implant microbiota by depleting commensal and enriching pathogenic species. The composition of peri-implant microbiota may be influenced by smoking.

Influence of Smoking on Periodontal and Implant Therapy: A Narrative Review

BACKGROUND

smoking is considered the most modifiable risk factor for periodontal disease.

OBJECTIVE

the aim of this narrative review is to emphasize the effect of smoking on periodontal and implant therapy.

METHODS

The authors reviewed the literature reporting the clinical outcomes of smoking on periodontal surgical and nonsurgical treatment. The impact of smoking on implant therapy and sinus lifting procedures were also reviewed.

RESULTS

Periodontal and implant therapy outcomes are adversely affected by smoking. Smokers respond less favorably to periodontal therapy and periodontal flap procedures as compared to nonsmokers. Clinical outcomes for smokers are 50-75% worse than for nonsmokers. Studies reveal that smokers experience a significantly lower reduction in pocket depth compared to nonsmokers as well as less bone growth after treating infra-bony defects with guided tissue regeneration. The relative risk of implant failure is significantly higher in patients who smoke 20 cigarettes or more per day compared to nonsmokers. Additionally, smoking has also been shown to increase postoperative wound dehiscence and infection rates following sinus floor elevation. Longitudinal studies on smoke cessation have shown a reduction in bone loss and probing depths for periodontitis patients after cessation compared to those who smoke.

CONCLUSION

Smoking cessation can reduce probing depths and improve clinical attachment after nonsurgical periodontal therapy. There is insufficient evidence regarding the effect of smoking on peri-implantitis, as well as the loss of implants in the long-term.

Local and Systemic Antibiotics in Peri-Implantitis Management: An Umbrella Review

The present umbrella review aimed to characterize the type and regimen of antibiotics administered locally and/or systemically, alone or in combination with surgical and nonsurgical treatments, for peri-implantitis and to evaluate and compare the associated clinical, radiographic, and crevicular peri-implant outcomes. The secondary objective was to determine the most effective antibiotic type, route of administration, regimen, and protocols (antibiotics alone or in combination with other approaches) for treating peri-implantitis. The study protocol, which was developed in advance under the PRISMA statement, was registered at PROSPERO (CRD42022373957). BioMed Central, Scopus, MEDLINE/PubMed, the Cochrane Library databases, and the PROSPERO registry were searched for systematic reviews through 15 November 2022. Of the 708 records found, seven reviews were included; three were judged of a critically low and four of low quality through the AMSTAR 2 tool. Locally administered antibiotics alone or as an adjunct to surgical or nonsurgical treatments for peri-implantitis showed favorable outcomes, albeit with limited evidence. The administration of systemically-delivered antibiotics in combination with nonsurgical or surgical treatments remained questionable. Local plus systemic antibiotics have not been shown to have durable efficacy. Due to the heterogeneity of reported antibiotic types, routes, regimens, and protocols, no definitive conclusions could be drawn regarding the most effective antibiotic use in treating peri-implantitis.

Probiotics in Periodontal and Peri-Implant Health Management: Biofilm Control, Dysbiosis Reversal, and Host Modulation

Periodontitis and peri-implantitis are microbially associated diseases of the tissues supporting the teeth and dental implants that are mediated by host inflammation and eventually lead to tooth and dental implant loss. Given the probiotics' role in biofilm control, dysbiosis reversal, and host modulation, their potential beneficial effects on the improvement of periodontitis and peri-implantitis have been recently investigated. Moreover, probiotics use has also been proposed in periodontal health management in patients undergoing fixed orthodontic therapy. Therefore, the present study aimed to review, considering the periodontal microbiome composition around teeth and dental implants in healthy and pathological conditions, the putative favorable effects of probiotics on gingivitis, periodontitis, and peri-implantitis. The secondary aim of the present narrative review was to synthesize the supporting evidence and proposed protocols for probiotics use as adjuncts in periodontitis and peri-implantitis treatment and the periodontal health management of orthodontic patients with fixed appliances. Contrasting findings from the literature may be due to the different methods, posology, and duration of probiotics prescriptions and due to the heterogeneous biological and clinical measurement methods employed. Thus, no definitive conclusions could be drawn about the effectiveness of probiotics in periodontal management, both in healthy and pathological conditions. Further studies are needed to validate probiotics for periodontal management and provide recommended protocols.

Photodynamic Therapy for Peri-Implant Diseases

Peri-implant diseases are frequently presented in patients with dental implants. This category of inflammatory infections includes peri-implant mucositis and peri-implantitis that are primarily caused by the oral bacteria that colonize the implant and the supporting soft and hard tissues. Other factors also contribute to the pathogenesis of peri-implant diseases. Based on established microbial etiology, mechanical debridement has been the standard management approach for peri-implant diseases. To enhance the improvement of therapeutic outcomes, adjunctive treatment in the form of antibiotics, probiotics, lasers, etc. have been reported in the literature. Recently, the use of photodynamic therapy (PDT)/antimicrobial photodynamic therapy (aPDT) centered on the premise that a photoactive substance offers benefits in the resolution of peri-implant diseases has gained attention. Herein, the reported role of PDT in peri-implant diseases, as well as existing observations and opinions regarding PDT, are discussed.

In vitro antimicrobial effect of titanium anodization on complex multispecies subgingival biofilm

Anodization is a routine industrial galvanic method that produces a titanium oxide layer on the surface of titanium. Considering the possibility that this technique could influence microbial adsorption and colonization, this in vitro study was conducted to evaluate the impact of a process of anodization applied to a titanium surface on the microbial profile of multispecies subgingival biofilm. Titanium discs produced by using two different processes-conventional and Anodization-were divided into two groups: conventional titanium discs with machined surface (cpTi) Control Group and titanium discs with anodic oxidation treatment (anTi) Test Group. Subgingival biofilm composed of 33 species was formed on the titanium discs that were positioned vertically in 96-well plates, for 7 days. The proportions and the counts of microbial species were determined using a DNA-DNA hybridization technique, and data were evaluated using Mann-Whitney test (p < 0.05). Mean total bacterial counts were lower in Test Group in comparison with Control Group (p < 0.05). Nine bacterial species differed significantly, and were found in higher levels in Control Group in comparison with Test Group, including T. forsythia, E. nodatum, and F. periodonticum. In conclusion, titanium discs with anodization could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm the clinical impact of these findings.

Cross-kingdom microbial interactions in dental implant-related infections: is Candida albicans a new villain?

Candida albicans, an oral fungal opportunistic pathogen, has shown the ability to colonize implant surfaces and has been frequently isolated from biofilms associated with dental implant-related infections, possibly due to its synergistic interactions with certain oral bacteria. Moreover, evidence suggests that this cross-kingdom interaction on implant can encourage bacterial growth, leading to increased fungal virulence and mucosal damage. However, the role of Candida in implant-related infections has been overlooked and not widely explored or even considered by most microbiological analyses and therapeutic approaches. Thus, we summarized the scientific evidence regarding the ability of C. albicans to colonize implant surfaces, interact in implant-related polymicrobial biofilms, and its possible role in peri-implant infections as far as biologic plausibility. Next, a systematic review of preclinical and clinical studies was conducted to identify the relevance and the gap in the existing literature regarding the role of C. albicans in the pathogenesis of peri-implant infections.

Er:YAG laser irradiation enhances bacterial and lipopolysaccharide clearance and human gingival fibroblast adhesion on titanium discs

To investigate the effect of Er:YAG laser treatment on lipopolysaccharide (LPS) clearance and fibroblast adhesion on titanium disks. Grade IV titanium discs (n = 216) were used and allocated to 6 groups. Group 1 was the negative control without Porphyromonas gingivalis inoculation. Discs in Groups 2-6 were incubated with P. gingivalis to form a biofilm. Group 3 received 0.12% chlorhexidine irrigation and Group 4 received titanium curettage to remove the biofilm. Group 5 was treated with Er:YAG laser irradiation and Group 6 was treated with titanium curettage plus Er:YAG laser irradiation. The contact angle and surface roughness were measured after the various treatments. The surface microstructure and residual bacteria were examined using scanning electron microscopy and confocal laser scanning microscopy, respectively. Residual LPS was examined using a limulus amoebocyte lysate assay and human gingival fibroblast adhesion was quantified using fluorescent microscopy. Curettage plus Er:YAG laser irradiation was the most effective method for removing bacteria and LPS. No significant difference in the amount of fibroblast adhesion was found between the control and Group 6. Combined use of Er:YAG laser irradiation and curettage optimizes LPS clearance and fibroblast adhesion on titanium discs.

An In Vitro Analysis of Sodium Hypochlorite Decontamination for the Reuse of Implant Healing Abutments

The reuse of healing abutments (HAs) has become common practice in implant dentistry for economic concerns and the aim of this in vitro study was to assess the effect of sodium hypochlorite (NaOCl) in decontamination of HAs. A total of 122 HAs (used and sterilized [n = 107]; new [n = 15]) were procured from 3 centers, of which 3 samples were discarded due to perforation in the sterilization pouch. For sterility assessment, the used HAs (n = 80) were cultured in Brain Heart Infusion Broth (BHI) and potato dextrose agar (PDA); bacterial isolates were identified in 7 samples. Also, 24 used HAs were stained with phloxine B, photographed, and compared to new HAs (n = 5). A scanning electron microscope (SEM) assessed the differences between 2 sets of HAs, after which the 7 contaminated HAs along with 24 used HAs from staining experiment (total: 31) were subsequently treated with sodium hypochlorite (NaOCl) and SEM images were observed. About 8.75% of HAs tested positive in bacterial culture; Streptococcus sanguis, Dermabacter hominis, Staphylococcus haemolyticus, and Aspergillus species were isolated. Phloxine B staining was positive for used and sterilized HAs compared to controls. The SEM images revealed deposits in the used HAs and although treatment with NaOCl eliminated the contamination of cultured HAs, the SEM showed visible debris in the HA thread region. This in vitro study concluded that SEM images showed debris in used HAs at screw-hole and thread regions even though they tested negative in bacterial culture. The treatment with NaOCl of used HAs showed no bacterial contamination but the debris was observed in SEM images. Future studies on the chemical composition, biological implications, and clinical influence is warranted before considering reuse of HAs.

Adjunctive use of metronidazole-minocycline ointment in the nonsurgical treatment of peri-implantitis: A multicenter randomized controlled trial

BACKGROUND

Clinical benefits of local antibiotics as an adjunct to nonsurgical treatment of peri-implantitis have been widely reported, but most studies evaluated incipient peri-implantitis lesions, and showed incomplete treatment success rates.

PURPOSE

To assess the clinical and microbiological outcomes of administering metronidazole in combination with minocycline as a local adjunct to the nonsurgical treatment of peri-implantitis.

MATERIALS AND METHODS

One hundred and eighteen subjects with peri-implantitis were recruited in a four-center, three-arm, and 12-week randomized controlled trial. Subjects were randomly assigned to receive one of the following treatments: (a) MM-mechanical debridement + metronidazole-minocycline ointment, (b) MC-mechanical debridement + minocycline ointment, (c) NST-mechanical debridement only.

RESULTS

Except for four subjects who was excluded during the trial, a total of 114 patients with 114 implants (one implant per each patient) finally completed the trial and were included in the analyses. Multivariate logistic regression analysis revealed that the treatment success rates (absence of bleeding or suppuration on probing, and sites showing pocket probing depth [PPD] ≥5 mm) on at 12 weeks were higher in MM-group patients (31.6%) and MC-group patients (20.5%) compared to NST-group patients (2.7%; p = 0.011 and 0.040, respectively). Subjects with deepest PPD ≥8 mm showed a significant difference in the PPD reduction between MM and MC groups at week 4 (p = 0.025) and week 12 (p = 0.047). Detection ratio of Tannerella forsythia was significantly lower for MM group than MC group (p = 0.038).

CONCLUSIONS

Additive use of either MM or MC results in significantly higher treatment success rates compared to sole mechanical debridement in nonsurgical treatment of peri-implantitis. Moreover, MM contributes to a significantly greater reduction in the PPD compared to MC in deep pockets (cris.nih.go.kr KCT0004557).

At which bone level are implants explanted?

OBJECTIVES

Clear guidelines when to remove an implant are missing. The aim of this study was to evaluate the amount of peri-implant bone loss at explantation by specialists.

MATERIAL AND METHODS

Implantology specialists were asked to provide implants explanted due to peri-implantitis with related clinical information. Early failures (survival time <12 months) were analyzed separately. Questionnaires inquired age, sex, smoking, implant location, usage of bone substitutes, and implant brand. Explants were measured and bone loss was assessed using radiographs. Covariate-adjusted mixed-effects models were evaluated for bone loss and survival time.

RESULTS

Twelve dental offices provided 192 explants from 161 patients with 99 related radiographs. Thirty-three (17.2%) explants were early failures. Excluding early failures, average survival time was 9.5 ± 5.8 years with absolute and relative bone loss of 7.0 ± 2.7 mm and 66.2 ± 23.7%, respectively. Late failures were removed at mean bone loss of 57.7% in the maxilla and 73.7% in the mandible irrespective of survival time. In fully adjusted mixed-effects models, only age at implantation (B = -0.19; 95% CI: -0.27, -0.10) remained a significant factor for survival time. Implants exhibited significantly more relative bone loss if they were positioned in the mandible (B = 17.3; 95% CI: 3.91, 30.72) or if they were shorter (B = -2.79; 95% CI: -5.50, -0.08).

CONCLUSIONS

Though the mean bone loss (66.2%) at which implants were explanted was in accordance with the literature, its wide variation and differentiation between jaws showed that the profession has no universally accepted threshold beyond which an implant cannot be preserved.

Immunological Aspects of Dental Implant Rejection

Nowadays, dental implants are a prominent therapeutic approach among dentists for replacing missing teeth. Failure in dental implants is a severe challenge recently. The factors which lead to dental implant failure are known. These factors can be categorized into different groups. In this article, we discussed the immunological aspects of implant failure as one of these groups. Cytokines and immune cells have extensive and various functions in peri-implantitis. The equilibrium between pro and anti-inflammatory cytokines and cells, which involve in this orchestra, has a crucial role in implant prognosis. In conclusion, immune cells, especially macrophages and dendritic cells, almost increased in the patients with implant failure. Also, proinflammatory cytokines were proposed as diagnostic factors according to their higher levels in dental implant rejection.

Er,Cr:YSGG laser surface treatment of gamma titanium aluminide: Scanning electron microscopy-energy-dispersive X-ray spectrometer analysis, wettability and Eikenella corrodens and Aggregatibacter actinomycetemcomitans bacteria count-in vitro study

Dental implants play an important role in oral health. Titanium dental implants must endure the complex microflora environment of the oral cavity. Moreover, bacterial infections have been considered as one of the most important factors of implant failure. The issue of dental improvement through modification of chemical composition and surface treatment has received considerable critical attention. γ-TiAl as a novo biocompatible material revealed a slower corrosion rate in biological media rather Ti-6Al-4V. The objective of this study is to investigate the effect of Er,Cr:YSGG laser on γ-TiAl in comparison with sandblasted and acid-etched samples as the control groups and machined samples.Wettability, surface roughness, surface topography, scanning electron microscopy-energy dispersive X-ray spectrometer analysis of surface and subsurface of samples were investigated and bacteria counts of two periodontal bacterial strains (Aggregatibacter actinomycetemcomitans and Eikenella corrodens) were evaluated on the Er,Cr:YSGG laser surface-treated sandblasted and acid-etched and machined samples.The results of this investigation show that Er,Cr:YSGG laser surface treatment affects surface roughness, surface topography, wettability, chemical composition of the surface and bacteria count. Scanning electron microscopy-energy dispersive X-ray spectrometer analysis of the sample revealed the increment of titanium and oxygen content and reduction of aluminum content in the surface and subsurface layer. A. actinomycetemcomitans and E. corrodens count were found from the lowest level to highest in the sandblasted and acid-etched samples, laser samples and machined samples, respectively.Using controlled parameters of Er,Cr:YSGG laser ensured no significant adverse alteration. The findings to emerge from this study revealed the significant correlation between microbial count and wettability. Furthermore, the contact angle strongly correlated with surface roughness.

The Microbiome of Peri-Implantitis: A Systematic Review and Meta-Analysis

This review aimed to systematically compare microbial profiles of peri-implantitis to those of periodontitis and healthy implants. Therefore, an electronic search in five databases was conducted. For inclusion, studies assessing the microbiome of peri-implantitis in otherwise healthy patients were considered. Literature was assessed for consistent evidence of exclusive or predominant peri-implantitis microbiota. Of 158 potentially eligible articles, data of 64 studies on 3730 samples from peri-implant sites were included in this study. Different assessment methods were described in the studies, namely bacterial culture, PCR-based assessment, hybridization techniques, pyrosequencing, and transcriptomic analyses. After analysis of 13 selected culture-dependent studies, no microbial species were found to be specific for peri-implantitis. After assessment of 28 studies using PCR-based methods and a meta-analysis on 19 studies, a higher prevalence of Aggregatibacter actinomycetemcomitans and Prevotella intermedia (log-odds ratio 4.04 and 2.28, respectively) was detected in peri-implantitis biofilms compared with healthy implants. Actinomyces spp., Porphyromonas spp. and Rothia spp. were found in all five pyrosequencing studies in healthy-, periodontitis-, and peri-implantitis samples. In conclusion, the body of evidence does not show a consistent specific profile. Future studies should focus on the assessment of sites with different diagnosis for the same patient, and investigate the complex host-biofilm interaction.

The Impact of Smoking on Subgingival Microflora: From Periodontal Health to Disease

Periodontal disease is one of the most common diseases of the oral cavity affecting up to 90% of the worldwide population. Smoking has been identified as a major risk factor in the development and progression of periodontal disease. It is essential to assess the influence of smoking on subgingival microflora that is the principal etiological factor of the disease to clarify the contribution of smoking to periodontal disease. Therefore, this article reviews the current research findings regarding the impact of smoking on subgingival microflora and discusses several potential mechanisms. Cultivation-based and targeted molecular approaches yield controversial results in determining the presence or absence of smoking-induced differences in the prevalence or levels of certain periodontal pathogens, such as the “red complex.” However, substantial changes in the subgingival microflora of smokers, regardless of their periodontal condition (clinical health, gingivitis, or periodontitis), have been demonstrated in recent microbiome studies. Available literature suggests that smoking facilitates early acquisition and colonization of periodontal pathogens, resulting in an “at-risk-for-harm” subgingival microbial community in the healthy periodontium. In periodontal diseases, the subgingival microflora in smokers is characterized by a pathogen-enriched community with lower resilience compared to that in non-smokers, which increases the difficulty of treatment. Biological changes in key pathogens, such as Porphyromonas gingivalis, together with the ineffective host immune response for clearance, might contribute to alterations in the subgingival microflora in smokers. Nonetheless, further studies are necessary to provide solid evidence for the underlying mechanisms.

Molecular tools for preventing and improving diagnosis of peri-implant diseases

Peri-implantitis is an inflammatory disease of tissues surrounding osseointegrated dental implants. Inflammation affecting soft and hard peri-implant tissues can cause alveolar bone resorption and subsequent implant loss. Clinical surveillance and early diagnosis are of paramount importance to reduce clinical failures and improve implant survival. Current diagnosis of implants is based on clinical and radiological signs. Molecular tests are an emerging diagnostic methodology, which potentially can help to detect and prevent early peri-implantitis and monitor the efficacy of therapy as well. A plethora of potential biomarkers are potentially available to support the clinical diagnosis of peri-implantitis. However, conflicting diagnostic conclusions have been reached, probably related to weak statistical results due to limited sample size or disease heterogeneity. The present paper reviews candidate diagnostic biomarkers for peri-implantitis, including infective agents, genetic susceptibility factors, and key proteins related to inflammation and tissue remodeling.

Effect of Smoking and Locations of Dental Implants on Peri-Implant Parameters: 3-Year Follow-Up

Background

Smoking may be a risk factor for marginal bone loss (MBL) and oral mucosal inflammation surrounding dental implants. This retrospective study evaluated the effects of smoking on dental implants in patients with fixed implant-supported prostheses over a period of 36 months following loading.

Material/Methods

We assessed 120 patients (68 women, 52 men, ages 19–74 years (mean age: 55.10 years) with 315 implants. Implants were classified according to location in the upper and lower jaws and anterior (placed between canines) or posterior (placed between pre-molars and molars) as follows: 1=maxilla anterior, 2=maxilla posterior, 3=mandible anterior, 4=mandible posterior. We also measured MBL, plaque index (PI), sulcus bleeding index (SBI), and probing depth (PD). P-values less than 0.05 were considered statistically significant.

Results

MBL was statistically greater in smokers (P<0.001) as compared to non-smokers in both jaws. MBL did not vary significantly by location in either group (smokers: p=0.415; non-smokers: p=0.175). Mean PI and PD scores were significantly higher in smokers as compared to non-smokers (P<0.001). A positive correlation was found between PI and PD scores in both groups. No statistically significant difference in SBI was observed between the 2 groups (P>0.05).

Conclusions

Smoking was associated with increases in marginal bone loss around implants, independent of their location in the jaws. Also, both plaque indices and probing depths were greater in smokers than in non-smokers.

Current weight of evidence of viruses associated with peri-implantitis and peri-implant health: A systematic review and meta-analysis

The pathological role of human herpesviruses (HHVs) (Epstein-Barr virus [EBV], Human cytomegalovirus [CMV], and Herpes simplex virus [HSV]) in peri-implant health needs clarification quantitatively. To determine the weight of evidence for HHVs in patients with peri-implantitis (PI) and substantiate the significance of HHVs in peri-implant inflammation, electronic databases including EMBASE, MEDLINE, Cochrane Oral Health Group Trials Register, and Cochrane Central Register of Controlled Trials were searched from 1964 up to and including November 2018. Meta-analyses were conducted for prevalence of HHVs in PI and healthy controls. Forest plots were generated that recorded risk difference (RD) of outcomes and 95% confidence intervals (CI). Five clinical studies were considered and included. Four clinical studies reported data on EBV while three clinical studies reported data on CMV. Considering the risk of these viruses in PI, significant heterogeneity for CMV (χ²  = 53.37, p < 0.0001, I²  = 96.25%) and EBV (χ²  = 14.14, p = 0.002, I²  = 78.79%) prevalence was noticed between PI and healthy control sites. The overall RD for only EBV (RD = 0.20, 95% CI, 0.01-0.40, p = 0.03) was statistically significant between both groups. Frequencies of the viruses were increased in patients with PI compared with healthy nondiseased sites. However, the findings of the present study should be interpreted with caution because of significant heterogeneity and small number of included studies.

Surgical Therapy of Peri-Implantitis with Local Minocycline: A 6-Month Randomized Controlled Clinical Trial

The purpose of this study was to determine the clinical, microbial, and radiographic effects of local minocycline combined with surgical treatment of peri-implantitis. Fifty patients with peri-implantitis were recruited, and surgical treatment with the local application of either minocycline or placebo ointment was performed. The application of minocycline was repeated with supragingival debridement at 1, 3, and 6 mo postoperatively. Plaque index, gingival index (GI), probing pocket depth (PPD), and bleeding/suppuration on probing were measured at baseline and 1-, 3-, and 6-mo evaluations. The change in supporting bone level (SBL) measured with cone beam computed tomography was analyzed between baseline and 6 mo. Microbial analysis was performed with real-time polymerase chain reaction. Both groups exhibited improvements in clinical and radiographic measurements after surgical treatment. There was a significant difference in the changes of mean PPD between the test and control groups (2.68 ± 1.73 and 1.55 ± 1.86 mm, respectively, P = 0.039). The changes of mean GI and SBL differed significantly between the groups (ΔGI: 0.83 ± 0.60 and 0.40 ± 0.68; ΔSBL: 0.72 ± 0.56 and 0.31 ± 0.49 mm, respectively, P = 0.026 and 0.014). Treatment success rates (defined as PPD <5 mm, absence of bleeding/suppuration on probing, and no further bone loss) were 66.7% and 36.3% in the test and control groups, respectively. The count of red complex bacteria tended to decrease in both groups until 6 mo; however, no significant intergroup difference was found. None of the patients in the test group carried Porphyromonas gingivalis or Tannerella forsythia at 6 mo. These findings indicate that the repeated local delivery of minocycline combined with surgical treatment provides significant benefits in terms of clinical parameters and radiographic bone fill, with a higher treatment success rate in the short healing period (cris.nih.go.kr KCT0002844).

Titanium as a modifier of the peri-implant microbiome structure

BACKGROUND

Recent data support the implication of accelerated titanium dissolution products in peri-implantitis. It is unknown whether these dissolution products have an effect on the peri-implant microbiome, the target of existing peri-implantitis therapies.

PURPOSE

This study assessed the relationship between the peri-implant microbiome, dissolved titanium levels, and peri-implantitis.

MATERIALS AND METHODS

Clinical, microbiome, and titanium data were collected from a periodontal population having implants in function for 10 years. Clinical examinations were performed, and submucosal plaque samples were collected from the deepest site per implant. An aliquot of the sample was used for 16S rRNA gene sequencing, with the remainder analyzed for titanium quantity using mass spectrometry. Sequences were clustered into taxonomic units at 97% minimum sequence similarity using the QIIME pipeline approach.

RESULTS

Fifteen implants were assessed. According to established case definitions, six had a diagnosis of peri-implantitis; nine were healthy. The genera Streptococcus, Prevotella and Haemophilus characterized peri-implant health. Peri-implantitis was associated with a marked increase in Veillonella. Quantities of dissolved titanium were identified in 40% of sites. Titanium presence was associated with peri-implant disease status (P = .02) and correlated to the first principal component of the microbiome (rho = 0.552) and its alpha-diversity (rho = -0.496). Canonical correlation analyses found that titanium levels, but not health or disease status of the implant, were significantly associated with the microbiota composition (P = .045).

CONCLUSIONS

These findings suggest an association between titanium dissolution products and peri-implantitis and support a role for these products in modifying the peri-implant microbiome structure and diversity.

In vivo expression of proteases and protease inhibitor, a serpin, by periodontal pathogens at teeth and implants

Porphyromonas gingivalis and Tannerella forsythia secrete proteases, gingipains and KLIKK-proteases. In addition, T. forsythia produces a serpin (miropin) with broad inhibitory spectrum. The aim of this pilot study was to determine the level of expression of miropin and individual proteases in vivo in periodontal and peri-implant health and disease conditions. Biofilm and gingival crevicular fluid (GCF)/ peri-implant sulcular fluid (PISF) samples were taken from healthy tooth and implant sites (n = 10), gingivitis and mucositis sites (n = 12), and periodontitis and peri-implantitis sites (n = 10). Concentration of interleukin-8 (IL-8), IL-1β and IL-10 in GCF was determined by enzyme-linked immunosorbent assay. Loads of P. gingivalis and T. forsythia and the presence of proteases and miropin genes were assessed in biofilm by quantitative PCR, whereas gene expression was estimated by quantitative RT-PCR. The presence of P. gingivalis and T. forsythia, as well as the level of IL-8 and IL-1β, were associated with disease severity in the periodontal and peri-implant tissues. In biofilm samples harboring T. forsythia, genes encoding proteases were found to be present at 72.4% for karilysin and 100% for other KLIKK-protease genes and miropin. At the same time, detectable mRNA expression of individual genes ranged from 20.7% to 58.6% of samples (for forsylisin and miropsin-1, respectively). In comparison with the T. forsythia proteases, miropin and the gingipains were highly expressed. The level of expression of gingipains was associated with those of miropin and certain T. forsythia proteases around teeth but not implants. Cumulatively, KLIKK-proteases and especially miropin, might play a role in pathogenesis of both periodontal and peri-implant diseases.

Alterations in oral microbial flora induced by waterpipe tobacco smoking

Background

Waterpipe smoking is a global health problem and a serious public concern. Little is known about the effects of waterpipe smoking on oral health. In the current study, we examined the alterations of oral microbial flora by waterpipe smoking.

Methods

One hundred adult healthy subjects (59 waterpipe smokers and 41 non-smokers) were recruited into the study. Swabs were taken from the oral cavity and subgingival regions. Standard culturing techniques were used to identify types, frequency, and mean number of microorganisms in cultures obtained from the subjects.

Results

It was notable that waterpipe smokers were significantly associated with a history of oral infections. In subgingiva, Acinetobacter and Moraxella species were present only in waterpipe smokers. In addition, the frequency of Candida albicans was higher in the subgingiva of waterpipe smokers (p = 0.023) while the frequency of Fusobacterium nucleatum was significantly lower in the subgingiva of waterpipe smokers (p = 0.036). However, no change was observed in other tested bacteria, such as Campylobacter species; Viridans group streptococci, Enterobacteriaceae, and Staphylococcus aureus. In oral cavity and when colony-forming units were considered, the only bacterial species that showed significant difference were the black-pigmented bacteria (p < 0.001).

Conclusion

This study provides evidence indicating that some of the oral microflora is significantly altered by waterpipe smoking.

Comprehensive Treatment of Severe Periodontal and Periimplant Bone Destruction Caused by Iatrogenic Factors

Dental implant success requires placement after periodontal therapy, with adequate bone volume, plaque control, primary stability, control of risk factors, and use of well-designed prostheses. This report describes the surgical and prosthetic management of a patient with severe iatrogenic periodontal/periimplant bone destruction. Methods. A 55-year-old female smoker with fixed partial dentures (FPDs) supported on teeth and implants presented with oral pain, swelling, bleeding, and a 10-year history of multiple implant placements and implants/prosthesis failures/replacements. Radiographs showed severe bone loss, subgingival caries, and periapical lesions. All implants and teeth were removed except implants #4 and #10 which served to retain an interim maxillary restoration. Bone defects were covered with nonresorbable dPTFE membranes. In the mandible, three new implants were placed and loaded immediately with a bar-retained temporary denture. Results. Seven months postoperatively, the bone defects were regenerated, and three additional mandibular implants were placed. All mandibular implants were splinted and loaded with a removable overdenture. Conclusions. In this case, periimplant infection and tissue destruction resulted from the lack of periodontal treatment/maintenance and failure to use evidence-based surgical and loading protocols. Combination therapy resolved the disease and the patient's severe discomfort while providing immediate function and an aesthetic solution.

Microbiome and Microbial Biofilm Profiles of Peri-Implantitis: A Systematic Review

BACKGROUND

This systematic review assesses microbiologic profiles of peri-implantitis, periodontitis, and healthy implants based on studies that evaluated microbial biofilms and entire microbiomes to establish their similarities and differences.

METHODS

The Medical Literature Analysis and Retrieval System Online via PubMed, Excerpta Medica Database, and Cochrane Central Register of Controlled Trials, were searched without language restrictions through July 30, 2016. Observational studies that evaluated microbial profiles or entire microbiomes of peri-implantitis compared with healthy implants or periodontitis were considered eligible for inclusion. A descriptive summary was created to determine quantity of data and interstudy variations.

RESULTS

Of 126 potentially eligible articles, 26 were included in this study. Twenty-one of these articles evaluated the microbiologic profile of peri-implantitis versus healthy implants or periodontitis using conventional microbiologic techniques. Five articles evaluated the entire microbiome using genomic sequencing. Teeth with periodontitis, healthy implants, or implants with peri-implantitis were colonized by periodontal microorganisms. Porphyromonas gingivalis and especially Prevotella intermedius/nigrescens were often identified at peri-implantitis sites. Peri-implantitis sites were also colonized by uncultivable asaccharolytic anaerobic Gram-positive rods and anaerobic Gram-negative rods, which were not frequently identified in teeth with periodontitis or healthy implants. Opportunistic microorganisms were not found very frequently in peri-implantitis sites.

CONCLUSIONS

Peri-implantitis represents a heterogeneous mixed infection that includes periodontopathic microorganisms, uncultivable asaccharolytic anaerobic Gram-positive rods and other uncultivable Gram-negative rods, and, rarely, opportunistic microorganisms such as enteric rods and Staphylococcus aureus. Sequencing methods that evaluate the entire microbiome improve identification of microorganisms associated with peri-implantitis.

Isolation and Identification of Nonoral Pathogenic Bacteria in the Oral Cavity of Patients with Removable Dentures

Aims and Objectives:

Dentures in the oral cavity may act as a reservoir of microorganisms, which may be related to systemic infections. The aim of this study was to investigate the nonoral pathogenic bacteria in the oral cavity of patients with removable dentures in Shiraz, Southern Iran.

Materials and Methods:

The bacterial flora of saliva samples from 50 men and 50 women with removable dentures and 100 age- and sex-matched controls with normal dentate were compared using culture, Gram staining, and API20E Kit methods. All data were analyzed using SPSS software.

Results:

Except for Enterobacter cloacae isolate (P = 0.03), there was no significant difference between both groups for the presence of Escherichia coli, Klebsiella pneumoniae, nonfermenting Gram-negative bacilli, Raoultella ornithinolytica, Raoultella planticola, Kluyvera spp., and Enterobacter aerogenes. No significant correlation was noticed between age and presence of bacteria in the oral cavity. The Gram-negative rod bacteria were more in males, but the difference was not significant. When a total of Gram-negative rods were considered, there was a significant difference between case and control groups (P = 0.004).

Conclusions:

Based on our findings that nonoral pathogenic bacteria are detected from the saliva of the denture wearers, general and oral health measures in patients with removable dentures should be adopted to decrease the risk of cross infection.

Microbiota Analysis of Biofilms on Experimental Abutments Mimicking Dental Implants: An In Vivo Model

BACKGROUND

The microbiota colonizing dental implants has been said to be similar to the microbiome surrounding teeth. In the absence of inflammation, a biofilm with pathologic bacteria can cover implant surfaces exposed to the oral cavity, for example, due to a remodeling process. The aim of the present study is to identify microbiota surrounding exposed dental implants in patients with and without a history of periodontitis through a deep-sequencing approach.

METHODS

An experimental abutment with the same surface and structure as a commercially available dental implant was used. Bacterial DNA was isolated, and the 16S ribosomal RNA gene was amplified and sequenced. Multiplexed tag-encoded sequencing of DNA from the samples was performed, and the reads were processed by metagenomic rapid annotation.

RESULTS

A wide variety of bacteria, 96 species, were identified. The most frequently found bacteria were Fusobacterium nucleatum and Prevotella denticola. Some species generally associated with periodontitis were found to a greater extent in patients without a history of periodontitis. Some bacteria that have never been described as part of the oral microbiome were identified in the present sample.

CONCLUSIONS

Analysis of data suggests that the bacteria surrounding exposed dental implants form a diverse microbiome regardless of the periodontal profile of patients. Further research is needed to clarify the role of these microorganisms in the oral environment.

Community analysis of dental plaque and endotracheal tube biofilms from mechanically ventilated patients

PURPOSE

Mechanically ventilated patients are at risk for developing ventilator-associated pneumonia, and it has been reported that dental plaque provides a reservoir of respiratory pathogens that may aspirate to the lungs and endotracheal tube (ETT) biofilms. For the first time, metataxonomics was used to simultaneously characterize the microbiome of dental plaque, ETTs, and non-directed bronchial lavages (NBLs) in mechanically ventilated patients to determine similarities in respective microbial communities and therefore likely associations.

MATERIAL AND METHODS

Bacterial 16S rRNA gene sequences from 34 samples of dental plaque, NBLs, and ETTs from 12 adult mechanically ventilated patients were analyzed.

RESULTS

No significant differences in the microbial communities of these samples were evident. Detected bacteria were primarily oral species (e.g., Fusobacterium nucleatum, Streptococcus salivarius, Prevotella melaninogenica) with respiratory pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcuspneumoniae, and Haemophilus influenzae) also in high abundance.

CONCLUSION

The high similarity between the microbiomes of dental plaque, NBLs, and ETTs suggests that the oral cavity is indeed an important site involved in microbial aspiration to the lower airway and ETT. As such, maintenance of good oral hygiene is likely to be highly important in limiting aspiration of bacteria in this vulnerable patient group.

In Vitro-Activity of Er:YAG Laser in Comparison with other Treatment Modalities on Biofilm Ablation from Implant and Tooth Surfaces

BACKGROUND AND AIM

Bacterial biofilms play a major role in the etiology of periodontal and peri-implant diseases. The aim of the study was to evaluate the removal of bacterial biofilms and attachment of epithelial cells (EC), gingival fibroblasts (GF) and osteoblast-like cells (OC) to dentin and titanium surfaces after Er:YAG laser (Er:YAG) in comparison with other treatment methods.

MATERIAL AND METHODS

Multi-species bacterial biofilms were grown on standardized dentin and titanium specimens with a sand-blasted and acid etched (SLA) surface for 3.5 d. Thereafter, the specimens were placed into artificially-created pockets. The following methods for biofilm removal were used: 1) Gracey (dentin) or titanium curettes (CUR), 2) Er:YAG, 3) photodynamic therapy (PDT) and 4) CUR with adjunctive PDT (CUR/PDT). Colony forming units (CFUs) of the remaining biofilms and attachment of EC, GF and OC were determined. Statistical analysis was performed by means of ANOVA with post-hoc LSD.

RESULTS

All treatment methods decreased statistically significantly (p<0.001) total CFUs in biofilms compared with untreated dentin and titanium surfaces respectively. On dentin, Er:YAG was equally efficient as CUR and PDT but inferior to CUR/PDT (p = 0.005). On titanium, surfaces, the use of Er:YAG resulted in statistically significantly superior biofilm removal compared to the 3 other treatments (each p<0.001). Counts of attached EC, GF and OC were the lowest on untreated contaminated dentin and titanium surfaces each. After CUR/PDT higher EC counts were found on dentin (p = 0.006). On titanium, all decontamination methods statistically significantly increased (p<0.001) the counts of attached EC without differences between groups. Statistically significantly higher counts of GF (p = 0.024) and OC (p<0.001) were observed after Er:YAG decontamination compared with untreated surfaces.

CONCLUSION

Ablation of subgingival biofilms and in particular decontamination of titanium implant surfaces with an Er:YAG laser seem to be a promising approach and warrants further investigations.

The impact of antimicrobial photodynamic therapy on peri-implant disease: What mechanisms are involved in this novel treatment?

According to the American Academy of Implant Dentistry, 3 million Americans have dental implants, and this number is growing by 500,000 each year. Proportionally, the number of biological complications is also increasing. Among them, peri-implant disease is considered the most common cause of implant loss after osseointegration. In this context, microorganisms residing on the surfaces of implants and their prosthetic components are considered to be the primary etiologic factor for peri-implantitis. Some research groups have proposed combining surgical and non-surgical therapies with systemic antibiotics. The major problem associated with the use of antibiotics to treat peri-implantitis is that microorganisms replicate very quickly. Moreover, inappropriate prescription of antibiotics is not only associated with potential resistance but also and most importantly with the development of superinfections that are difficult to eradicate. Although antimicrobial photodynamic therapy (aPDT) was discovered several years ago, aPDT has only recently emerged as a possible alternative therapy against different oral pathogens causing peri-implantitis. The mechanism of action of aPDT is based on a combination of a photosensitizer drug and light of a specific wavelength in the presence of oxygen. The reaction between light and oxygen produces toxic forms of oxygen species that can kill microbial cells. This mechanism is crucial to the efficacy of aPDT. To help us understand conflicting data, it is necessary to know all the particularities of the etiology of peri-implantitis and the aPDT compounds. We believe that this review will draw attention to new insights regarding the impact of aPDT on peri-implant disease.

Bacterial colonization of the peri-implant sulcus in dentate patients: a prospective observational study

OBJECTIVES

The aim of the present study was to compare the composition of the periodontal microflora at baseline (T0) with the submucosal microflora at least 1 year after implant placement (T1) in periodontally healthy patients.

MATERIAL AND METHODS

For all 169 consecutive patients that visited our clinic during 1 year, we determined their periodontal parameters, implant mucosal index, and presence of implant calculus. At T0, self-reported smoking status was recorded and subgingival and submucosal biofilm samples were obtained and analyzed for the presence and numbers of selected periodontal pathogens. All measurements were repeated at T1.

RESULTS

One hundred twenty patients completed the study. Periodontal parameters were stable or had improved at T1. The total bacterial load was lower at implant sites (P < 0.05). The prevalence of Porphyromonas gingivalis was low at baseline, but at T1, detection rate and numbers were higher at implant sites compared to dentate sites. At T1, the frequency of detection of P. gingivalis (P = 0.01), Parvimonas micra (P = 0.018), and Fusobacterium nucleatum (P = 0.035) was higher in smoking patients (n = 23) than in non-smokers (n = 97).

CONCLUSIONS

Colonization of the submucosal peri-implant area is similar to the composition of subgingival microbiota. Smoking has a measurable effect on the colonization of implant-associated biofilms and may select for P. gingivalis, P. micra, and F. nucleatum.

CLINICAL RELEVANCE

The colonization of implants by well-known periodontal pathogens is very similar to that in normal dentition, also in a healthy cohort. Smoking status was related with the prevalence of periodontal pathogens where smokers harbored more often periodontal pathogens such as P. gingivalis, P. micra, and F. nucleatum.

Effectiveness of enamel matrix derivative on the clinical and microbiological outcomes following surgical regenerative treatment of peri-implantitis. A randomized controlled trial

OBJECTIVE

This randomized clinical trial aimed at comparing radiological, clinical and microbial effects of surgical treatment of peri-implantitis alone or in combination with enamel matrix derivative (EMD).

METHODS

Twenty-six subjects were treated with open flap debridement and decontamination of the implant surfaces with gauze and saline preceding adjunctive EMD or no EMD. Bone level (BL) change was primary outcome and secondary outcomes were changes in pocket depth (PD), plaque, pus, bleeding and the microbiota of the peri-implant biofilm analyzed by the Human Oral Microbe Identification Microarray over a time period of 12 months.

RESULTS

In multivariate modelling, increased marginal BL at implant site was significantly associated with EMD, the number of osseous walls in the peri-implant bone defect and a Gram+/aerobic microbial flora, whereas reduced BL was associated with a Gram-/anaerobic microbial flora and presence of bleeding and pus, with a cross-validated predictive capacity (Q(2) ) of 36.4%. Similar, but statistically non-significant, trends were seen for BL, PD, plaque, pus and bleeding in univariate analysis.

CONCLUSION

Adjunctive EMD to surgical treatment of peri-implantitis was associated with prevalence of Gram+/aerobic bacteria during the follow-up period and increased marginal BL 12 months after treatment.

Peri-implant disease: what we know and what we need to know

Peri-implant disease is a serious problem that plagues today's dentistry, both in terms of therapy and epidemiology. With the expansion of the practice of implantology and an increasing number of implants placed annually, the frequency of peri-implant disease has greatly expanded. Its clinical manifestations, in the absence of a globally established classification, are peri-implant mucositis and peri-implantitis, the counterparts of gingivitis and periodontitis, respectively.

However, many doubts remain about its features. Official diagnostic criteria, globally recognized by the dental community, have not yet been introduced. The latest studies using metagenomic methods are casting doubt on the assumption of microbial equivalence between periodontal and peri-implant crevices. Research on most of the features of peri-implant disease remains at an early stage; moreover, there is not a commonly accepted treatment for it. In any case, although the evidence so far collected is limited, we need to be aware of the current state of the science regarding this topic to better understand and ultimately prevent this disease.

An in vitro study on disinfection of titanium surfaces

OBJECTIVE

The aim of this in vitro study was to evaluate the efficacy of different methods used for the decontamination of titanium surfaces previously infected with a Staphylococcus aureus biofilm.

MATERIALS AND METHODS

S. aureus biofilms were grown on three different titanium surfaces (n = 114); polished, sandblasted large-grit acid-etched (SLA) and SLActive. The experimental groups were divided into six different disinfection modalities as follows: (i) rinsing with phosphate-buffered saline, (ii) rinsing with chlorhexidine digluconate 0.2% (CHX), (iii) application of photodynamic therapy (PDT), (iv) use of cotton pellet, (v) use of titanium brush (TiB) and (vi) the use of TiB and PDT. The decontamination effect of each modality was evaluated by microbial culture analysis and by scanning electron microscopy imaging. Two-way analysis of variance (ANOVA) and Bonferroni's post hoc comparisons were used to compare mean differences between colony-forming units per millilitre (CFU/ml) values, surfaces and treatments (P < 0.025).

RESULTS

This study demonstrated that the combination protocol (TiB and PDT) was the most effective in reducing S. aureus (P < 0.025) on polished (2.0 × 10³  CFU/Disc) and SLA surface (6.9 × 10³  CFU/Disc). On the SLActive surface, the combination treatment was not significantly different to the TiB group (1.0 × 10⁵ CFU/Disc) or the PDT group (2.0 × 10⁵ CFU/Disc).

CONCLUSION

The combined technique of TiB and PDT was shown to be an efficient method in reducing the number of S. aureus in both polished and rough titanium surfaces. These findings prompt further investigations in titanium decontamination techniques with a combination of TiB and PDT within a natural microcosm bacterial environment.