Microbiological profile associated with peri-implant diseases in individuals with and without preventive maintenance therapy: a 5-year follow-up

Anatomical three-dimensional model with peri-implant defect for in vitro assessment of dental implant decontamination

OBJECTIVES

Access to the implant surface plays a significant role in effective mechanical biofilm removal in peri-implantitis treatment. Mechanical decontamination may also alter the surface topography of the implant, potentially increasing susceptibility to bacterial recolonization. This in vitro study aimed to evaluate a newly developed, anatomically realistic, and adaptable three-dimensional (3D)printed model with a peri-implant bone defect to evaluate the accessibility and changes of dental implant surfaces after mechanical decontamination treatment.

MATERIAL AND METHODS

A split model of an advanced peri-implant bone defect was prepared using 3D printing. The function of the model was tested by mechanical decontamination of the exposed surface of dental implants (Standard Implant Straumann AG) coated with a thin layer of colored occlusion spray. Two different instruments for mechanical decontamination were used. Following decontamination, the implants were removed from the split model and photographed. Image analysis and fluorescence spectroscopy were used to quantify the remaining occlusion spray both in terms of area and total amount, while scanning electron microscopy and optical profilometry were used to analyze alteration in the implant surface morphology.

RESULTS

The 3D model allowed easy placement and removal of the dental implants without disturbing the implant surfaces. Qualitative and quantitative assessment of removal of the occlusion spray revealed differences in the mechanism of action and access to the implant surface between tested instruments. The model permitted surface topography analysis following the decontamination procedure.

CONCLUSION

The developed 3D model allowed a realistic simulation of decontamination of implant surfaces with colored occlusion spray in an advanced peri-implant defect. 3D printing allows easy adaptation of the model in terms of the shape and location of the defect. The model presents a valuable tool for in vitro investigation of the accessibility and changes of the implant surface after mechanical and chemical decontamination.

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.

The use of monophasic implants as an alternative of implant-prosthetic rehabilitation in the posterior maxilla with no sinus lift

BACKGROUND

Over the years, numerous studies and advanced technologies about dental implants have been evolved from the traditional two-stage procedure to immediate loading. Implants located in the posterior maxillary region allow to achieve an appropriate prosthetic support. The aim of this work was to solve the atrophied posterior maxilla, through monophasic implants with flapless technique and intraoral electro-welding.

METHODS

In this study were enrolled 120 patients between 20 and 68 years old (mean age of 34.2 years), where females predominate with 53.1% compared to 46.9% males. The patients were presented at the Oral Surgery Clinic of the Aldent University (Tirana, Albania), for a period 2009-2019. Briefly, 310 monophasic implants were placed, TRAMONTE type (Milan, Italy), to the posterior maxilla thus avoiding the sinus, with dense and wide threads, of different lengths and widths. The surgical technique was minimally invasive, flapless one. Data were expressed as mean + standard error (SEM) of all the radiographic outcomes obtained; and as statistical analysis was used the Student's t-test. P<0.5 and P<0.05, were considered significant.

RESULTS

A part of the patients were hypertensive and type 2 diabetic, then a negligible part were smokers, also a lack of oral hygiene was observed in 40% of cases. After 5 years of observation, it appeared that 95.9% of the implants were successful. Furthermore, the mesial and distal bone loss during the first three years was 0.1 mm, while after 5 years no continuation of bone loss was observed.

CONCLUSIONS

The application of monophasic implants must be performed according to approved protocols, considering the conditions of the posterior maxillary region, obtaining in this way a safe dental implantation.

Implantoplasty Improves Clinical Parameters over a 2-Year Follow-Up: A Case Series

Background and Objectives: Peri-implantitis treatment is still undefined. Regenerative treatment is expensive and technically demanding due to the need to handle biomaterials, membranes and different methodologies of decontamination. Resective treatment and implantoplasty might be a viable solution. This case series presents a 24 month retrospective observational study of 10 peri-implantitis patients treated with implantoplasty. Materials and Methods: In the present case series, 10 peri-implantitis patients (20 implants) were treated with a resective approach and implantoplasty. Previous to implantoplasty, all patients underwent non-surgical treatment. This surgery consisted in a full-thickness flap and implant surface exposure. The exposed non-osseointegrated implant body was submitted to implantoplasty. The flap was apically repositioned and sutured. Patients were accompanied for 24 months. Results: The mean initial probing depth (PD) (PD = 5.37 ± 0.86 mm), bleeding on probing (BoP = 0.12 ± 0.06%) and suppuration (Sup = 0.01 ± 0.01%) decreased significantly at the 12 month evaluation (PD = 2.90 ± 0.39 mm; BoP = 0.01 ± 0.01% and Sup = 0.00 ± 0.00%). Between the 12 and 24 month evaluations, there were no significant clinical changes (PD = 2.85 ± 0.45 mm; BoP = 0.01 ± 0.01% and Sup = 0.00 ± 0.00%). Mucosal recession (MR) had a significant increase between the baseline and the first 12 months (0.69 ± 0.99 mm vs. 1.96 ± 1.33 mm), but there were no significant changes between the 12th and 24th month (1.94 ± 1.48 mm). The success rate was 100% without implant fracture or loss. Conclusions: Resective surgery and implantoplasty might be a valid option in some specific peri-implantitis cases. Properly designed clinical trials are needed to confirm this possibility.

Periodontitis and peri-implantitis tissue levels of Treponema denticola-CTLP and its MMP-8 activating ability

BACKGROUND AND AIMS

Chymotrypsin-like-proteinase of Treponema denticola (Td-CTLP) can stimulate the protein expression and activation of matrix metalloproteinase (MMP)-8 (or collagenase-2), a potent tissue destructive enzyme from gingival cells in vitro. The aims of this study were 1) to demonstrate the proMMP-8 (or latent MMP-8) activation by Td-CTLP in vitro and 2) to detect Td-CTLP and MMP-8 protein levels in the tissue samples of peri-implantitis and periodontitis patients.

MATERIALS AND METHODS

proMMP-8 activation by Td-CTLP was analyzed by immunoblots. Tissue specimens were collected from 38 systemically healthy and non-smoking patients; 14 of whom had moderate to severe periodontitis, 10 of whom were suffering from peri-implantitis, and finally 14 of whom showed no sign of periodontal inflammation nor radiological bone decay (control group). The immune-expression levels of MMP-8 and Td-CTLP in the epithelium and the connective tissue were analyzed immunohistochemically. A pixel color-intensity analyze was performed with ImageJ software (version 1.46c; Rasband WS, National Institutes of Health, Bethesda, MD, USA) to obtain a comparable numeral score for each patient's epithelium and connective tissue MMP-8 and Td-CTLP enzyme level.

RESULTS

Td-CTLP activated proMMP-8 in vitro by converting the 70-75 kDa proMMP-8 to 65 kDa active MMP-8. Also, lower molecular size 25-50 kDa parts of MMP-8 were formed. There was no statistically significant difference between the study groups in terms of their MMP-8 and Td-CTLP levels in the epithelium or in the connective tissue.

CONCLUSION

Regarding the limits of this study, it can thus be said that the Td-CTLP enzyme can activate the host proMMP-8 enzyme. Tissue protein levels of MMP-8 and Td-CTLP do not seem to be changed in peri-implantitis and in periodontitis.

The temporal shift of peri-implant microbiota during the biofilm formation and maturation in a canine model

OBJECTIVES

Although the mature peri-implant biofilm composition is well studied, there is very little information on the succession of in vivo dental implant colonization. The aim of this study was to characterize the temporal changes and diversity of peri-implant supra-mucosal and sub-mucosal microbiota during the process of the plaque maturation.

MATERIALS AND METHODS

Dental implants (n = 25) were placed in the mandible of 3 beagle dogs. Illumina MiSeq sequencing of the hypervariable V3-V4 region of the 16S rRNA gene amplicons was used to characterize the supra/sub-mucosal microbiota in the peri-implant niches at 1day (T1), 7days (T2), 14days (T3), 21days (T4) and 28days (T5) after Phase Ⅱ surgery of the healing abutment placement. QIIME, Mothur, LEfSe and R-package were used for downstream analysis.

RESULTS

A total of 1184 operational taxonomic units (OTUs), assigned into 22 phyla, 264 genera and 339 species were identified. In supra-mucosal niches, the alpha parameters of shannon, sobs and chao1 displayed significant differences between T1 and other time-points. However, in sub-mucosal niches, only sobs, chao1, and ace indexes displayed significant differences between T1 and T3, and T1 and T5. Beta-diversity showed statistically significant difference between T1 and T2, T3, T4, T5 within both sub-mucosal and supra-mucosal plaque. The phyla Bacteroidetes, Proteobacteria and Firmicutes were the most dominant phyla of both sub-mucosal and supra-mucosal niches at all time-points and Firmicutes increased during the maturation of peri-implant plaque. At the genus level, Neisseria decreased significantly after T1 suggesting the establishment of an anaerobic microenvironment. A decrease of Porphyromonas during the formation of sub-mucosal microbial community was also detected. Co-occurrence network analysis exhibited a more complicated co-occurrence relationship of bacterial species in the sub-mucosal niches. Fusobacterium nucleatum, Filifactor villosus, and some other species may play a crucial role in biofilm maturation.

CONCLUSIONS

The present results suggested that the development of peri-implant biofilm followed a similar pattern to dental plaque formation. Sub-mucosal biofilm may go through a more complicated procedure of maturation than supra-mucosal biofilm.

Analysis of the effects of prepared porcelain veneers and unprepared porcelain veneers on gingival crevicular flora based on high-throughput sequencing

The effect of tooth preparation on the gingival crevicular flora of abutment teeth during porcelain veneer treatment is not clear. The purpose of the present study was to analyze the difference between prepared porcelain veneers and unprepared porcelain veneers on gingival crevicular flora. High-throughput sequencing was used in the present study. A total of 20 patients (40 anterior teeth) with veneer restoration of anterior teeth were enrolled. They were divided into two groups: The prepared porcelain veneer group (group P, 11 cases, 19 anterior teeth) and unprepared porcelain veneer group (group U, 9 cases, 21 anterior teeth). After 2 years of follow-up, the restoration and healthy natural gingival crevicular fluid were collected to extract bacterial DNA. 16S ribosomal DNA high-throughput sequencing technique was used to compare the diversity of gingival sulcus flora structure between the prepared porcelain veneer and unprepared porcelain veneer groups. In addition, a healthy control group (group H) was also used for comparison. The Shannon index of the group U was lower than that of group H and group P. The abundance of Proteus in group U was higher than that in group H and group P at the phylum level (P<0.05). At the genus level, the abundance of Porphyromonas, Prevotella and Actinomycetes in group U was significantly higher than that in group H and group P (P<0.05). Compared with the group P, the bacterial diversity of the group U was lower, and the proportion of gingival sulcus pathogenic bacteria was higher. The unprepared porcelain veneer had a certain adverse effect on the periodontal tissue.

Short-term efficacy of a gel containing propolis extract, nanovitamin C and nanovitamin E on peri-implant mucositis: A double-blind, randomized, clinical trial

OBJECTIVE

To determine the efficacy of a gel containing propolis extract, nanovitamin C and nanovitamin E as adjuvant to mechanical debridement in the treatment of peri-implant mucositis (PM).

BACKGROUND

Propolis has anti-inflammatory and antibacterial effect that may improve peri-implant health.

METHODS

A randomized, double-blind study was performed on patients with at least one implant with PM. Participants received a professional prophylaxis and were instructed to use either test or a control gel as toothpaste three times/day for 1 month. Clinical and microbiological parameters were evaluated. PM resolution was considered in absence of bleeding on probing (BOP). Data were analysed with Mann-Whitney U, Wilcoxon signed-rank and chi-square tests.

RESULTS

Forty-six patients participated (23 in each group). After treatment, 26.1% of test patients showed complete PM resolution versus 0% in control group (p = .02). Significant reductions were observed in plaque index (p = .03), BOP (p = .04) and probing depths (p = .027) in test compared with control group. The reduction in Tannerella forsythia was statistically greater in test than in control group at 1-month follow-up (p = .02). Porphyromonas gingivalis was statistically reduced in test group from baseline to 1-month follow-up (p = .05).

CONCLUSION

Test gel clinically improved PM and showed certain antimicrobial effect after 1 month in comparison with control group. Further long-term clinical trials are required to confirm these results.

Oral prosthetic microbiology: aspects related to the oral microbiome, surface properties, and strategies for controlling biofilms

The oral cavity is an environment that allows for the development of complex ecosystems; the placement of prosthetic devices as a consequence of partial or total tooth loss may alter the diversity of microbial communities. Biofilms on the surface of materials used in dental prostheses can promote important changes in the mechanic and aesthetic properties of the material itself and may cause local and systemic diseases for the prosthetic wearer. This review presents the main features of the oral microbiome associated with complete or partial dentures and dental implants. The main diseases associated with microbial colonization of prosthetic surfaces, factors that may affect biofilm formation on prosthetic materials, as well as novel alternative therapies aiming to reduce biofilm formation and/or to eradicate biofilms formed on these materials are also explored.

Peri-implantitis is not periodontitis: Scientific discoveries shed light on microbiome-biomaterial interactions that may determine disease phenotype

Peri-implantitis is an immune-mediated biological complication that is attributed to bacterial biofilms on the implant surface. As both periodontitis and peri-implantitis have similar inflammatory phenotypes when assessed cross-sectionally, treatment protocols for peri-implantitis were modeled according to those used for periodontitis. However, lack of efficacy of antimicrobial treatments targeting periodontal pathogens coupled with recent discoveries from open-ended microbial investigation studies create a heightened need to revisit the pathogenesis of peri-implantitis compared with that of periodontitis. The tale of biofilm formation on intraoral solid surfaces begins with pellicle formation, which supports initial bacterial adhesion. The differences between implant- and tooth-bound biofilms appear as early as bacterial adhesion commences. The electrostatic forces and ionic bonding that drive initial bacterial adhesion are fundamentally different in the presence of titanium dioxide or other implant alloys vs mineralized organic hydroxyapatite, respectively. Moreover, the interaction between metal surfaces and the oral environment leads to the release of implant degradation products into the peri-implant sulcus, which exposes the microbiota to increased environmental stress and may alter immune responses to bacteria. Clinically, biofilms found in peri-implantitis are resistant to beta-lactam antibiotics, which are effective against periodontal communities even as monotherapies and demonstrate a composition different from that of biofilms found in periodontitis; these facts strongly suggest that a new model of peri-implant infection is required.

Breaking the wave of peri-implantitis

Peri-implant diseases are prevalent with a weighted mean prevalence rate of 43% across Europe and 22% across South and North America. Although the main etiologic agent is bacterial biofilm, a myriad of factors influence the initiation and progression of the disease. Unfortunately, the treatment of peri-implant diseases is at best favorable in the short term with a high rate of persistent inflammation and recurrence. Therefore, it is sensible to consider and control all potential factors that may predispose an implant to peri-implant tissue inflammation in an attempt to avoid the disease. This paper reviews recent evidence on factors that may predispose implants to peri-implantitis and measures that can be taken to prevent it.

Oral microbial profile variation during canine ligature-induced peri-implantitis development

Background

Dental implants have become well-established in oral rehabilitation for fully or partially edentulous patients. However, peri-implantitis often leads to the failure of dental implants. The aim of this study was to understand the core microbiome associated with peri-implantitis and evaluate potential peri-implantitis pathogens based on canine peri-implantitis model.

Results

In this study, three beagle dogs were used to build peri-implantitis models with ligature-induced strategy. The peri-implant sulcular fluids were collected at four different phases based on disease severity during the peri-implantitis development. Microbial compositions during peri-implantitis development were monitored and evaluated. The microbes were presented with operational taxonomic unit (OTU) classified at 97% identity of the high-throughput 16S rRNA gene fragments. Microbial diversity and richness varied during peri-implantitis. At the phylum-level, Firmicutes decreased and Bacteroides increased during peri-implantitis development. At the genus-level, Peptostreptococcus decreased and Porphyromonas increased, suggesting peri-implantitis pathogens might be assigned to these two genera. Further species-level and co-occurrence network analyses identified several potential keystone species during peri-implantitis development, and some OTUs were potential peri-implantitis pathogens.

Conclusion

In summary, canine peri-implantitis models help to identify several potential keystone peri-implantitis associated species. The canine model can give insight into human peri-implantitis associated microbiota.

Analysis of the Subgingival Microbiota in Implant-Supported Full-Arch Rehabilitations

Background: The etiology of peri-implantitis is multifactorial, and it is not directly linked to the quantitative amount of plaque. The aim of this study was to evaluate the influence of subgingival microbiota around implants supporting full-arch restorations on clinical indexes of peri-implant health. Method: 47 patients (54 full-arch fixed rehabilitations) were included. Based on the highest value of probing depth (PD), 47 implants (in the test arch), 40 natural teeth and 7 implants (in the antagonist arch) were selected for microbiological sampling (traditional PCR and real-time PCR). Periodontal indexes (plaque index, PlI; probing depth, PD; bleeding on probing, BOP; peri-implant suppuration, PS) and marginal bone loss were also recorded. Results: Despite abundant plaque accumulation, the peri-implant parameters were within normal limits. No statistical difference was found in the microbial population around the test implants and antagonist natural teeth. Treponema denticola was present in a significantly higher amount around implants with increased PlI. Implants with increased BOP showed a significant increase in Treponema denticola and Tannerella forsythia. A significantly higher presence of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia was identified around the implants affected by peri-implantitis and in smokers. Conclusions: Peri-implantitis is characterized by a complex and polymicrobial disease, that might be influenced by the qualitative profile of plaque. Smoking might also favor implant biological complications in full-arch fixed prosthesis.

Clinical Decision Making for Primary Peri-Implantitis Prevention: Practical Applications

FOCUSED CLINICAL QUESTION

When planning dental implant therapy, what risk-reduction strategies allow practitioners to select patients, sites, and restorative plans that decrease the incidence of peri-implant disease?

SUMMARY

With a marked increase in the number of patients receiving dental implants to treat partial or complete edentulism, it follows that the prevalence of peri-implant mucositis and peri-implantitis have increased. Risks associated with implant therapies may vary based upon underlying local, environmental, surgical, patient, prosthetic, and fixture-related factors. Furthermore, an emphasis on preventative measures and maintenance should be undertaken to avoid development and progression of peri-implant diseases. Thorough risk assessment, proper treatment planning, and early diagnosis and intervention are critical in the absence of definitive data of long-term success of treatments for peri-implant condition. Given the difficulty in intervention once peri-implantitis is established, identification of risk factors and development of treatment plans to address those factors before dental implant therapy is critical to the long-term health and success of dental implants.

CONCLUSIONS

A patient-centered, evidence based approach to dental implant treatment planning to reduce the risk for peri-implantitis should be undertaken. Systematic diagnosis of disease state(s) and evaluation of the etiologic and modifying risk factors for peri-implant diseases can yield more optimal outcomes to reduce peri-implantitis rates.

Sealing agent reduces formation of single and dual-species biofilms of Candida albicans and Enterococcus faecalis on screw joints at the abutment/implant interface

The aim of this research was to evaluate the efficacy of a commercial sealing agent at the abutment/implant interface against microleakage of single and dual-species biofilms of Candida albicans and Enterococcus faecalis into external hexagon (EH) and Morse taper (MT) prosthetic connections. A total of 216 samples of implants and their abutments were tested. Six groups (n = 36) were evaluated based on biofilm and period of incubation (7 and 14 days). The implant connections EH and MT (n = 18) were divided according to the use of the material (n = 9) (EH-T and MT-T: with the sealing agent; EH-C and MT-C: control). The biofilms were analyzed by microbial counting (CFU/mL) and SEM analysis and photographs of the material in the screw joints were also taken. Data were analyzed by Student t test, two-way ANOVA and Bonferroni test. For the single-species biofilms, there was a significant reduction in the growth of E. faecalis when compared MT-C and MT-T or EH-C and EH-T at 7 and 14 days. The same was observed for C. albicans biofilms. For dual-species biofilms of E. faecalis and C. albicans, the sealing agent was more effective in preventing microbial infiltration into the MT connection at 14 days, while microbial infiltration did not occur into EH connections even in absence of the sealing agent for both periods of evaluation. Overall, these data suggest that the presence of the sealing agent reduces or eliminates the microleakage of E. faecalis and C. albicans biofilms into the implants regardless of the period of incubation.

A Topical Desiccant Agent in Association with Manual Debridement in the Initial Treatment of Peri-Implant Mucositis: A Clinical and Microbiological Pilot Study

In patients presenting mucositis, effective sub-gingival debridement is crucial to prevent peri-implantitis. The aim of this randomized study was to assess the three-month (T1) effects of a locally delivered liquid desiccant agent with molecular hygroscopic properties, in association with manual debridement, at sites with peri-implant mucositis. Twenty-three patients presenting at least one implant with no radiographically detectable bone loss, a pocket probing depth (PPD) ≥ 4 mm, and bleeding on probing (BOP), were included. At baseline (T0), patients were randomly assigned to receive the aforementioned desiccant agent before debridement (Test-Group), or a Chlorhexidine 1% disinfectant gel after debridement (Control-Group). Treatments were repeated after seven and 14 days. Peri-implant soft tissue assessment [PPD, BOP, Modified Bleeding Index (mBI), Visible Plaque Index (VPI), and Modified Plaque Index (mPLI)] and microbial sampling were performed at T0 and T1. At T1 the Test-Group presented significantly greater reductions for BOP, mBI, VPI, and mPLI. Concerning the deepest sites of the treated implants, both groups showed statistically significant reductions for BOP and mBI between T0 and T1. Furthermore, the Test-Group exhibited a significant decrease in anaerobic bacteria. Despite these valid outcomes, a complete resolution of the inflammatory conditions was not achieved by any of the groups.