Effect of Antimicrobial Agent Coating on Physicochemical and Biologic Properties of Implant Abutments: A Systematic Review.

PURPOSE: To analyze the effectiveness of coating of abutments with antimicrobial agents and their influence on the physicochemical and biologic properties of the coated materials. MATERIALS AND METHODS: This work was registered in Open Science Framework (osf.io/6tkcp) and followed the PRISMA protocols. A search of two independent reviewers of articles published up to October 29, 2021, was performed in the Embase, PubMed, Science Direct, and Scopus databases. RESULTS: The databases found a total of 1,474 references. After excluding the duplicates, 1,050 remained. After reading the titles and abstracts and applying the inclusion criteria, 13 articles remained and were read in full. A total of 8 articles were included in this systematic review. Different antimicrobial agents have been used to coat abutments, including graphene oxide, polydopamine, titanium and zirconium nitride, lactoferrin, tetracycline, silver, and doxycycline with varied release times. Titanium-coated silver showed a better antimicrobial agent release time of up to 28 days. Chemical analysis confirmed the presence of antimicrobials on the surface after coating. Different pathogenic microorganisms, such as Streptococcus sanguinis, Streptococcus oralis, and Staphylococcus aureus, were inhibited when in contact with the coated surface. CONCLUSIONS: This review showed that there is still no consensus on which is the better antimicrobial agent and which coated materials have the better performance. However, the association of surface coating of abutments with antimicrobials is feasible and can benefit many patients, which can support their clinical use to favor the healing process and prevent infections that can lead to treatment failure with dental implants.

Candida albicans biofilms on different materials for manufacturing implant abutments and prostheses

BACKGROUND: Morphological, physical and chemical properties of both implants and prostheses can determine the biofilm formation on their surface and increase the risk of biological complications. The aim of this study was to evaluate the capacity of biofilm formation of Candida albicans on different materials used to manufacture abutments and prostheses. MATERIAL AND METHODS: Biofilm formation was analyzed on cp grade II titanium, cobalt-chromium alloy and zirconia, silicone, acrylic resin (polymethylmethacrylate) and nano-hybrid composite. Some samples were partially covered with lithium disilicate glass ceramic to study specifically the junction areas. C. albicans was incubated in a biofilm reactor at 37 °C with agitation. The biofilm formation was evaluated at 24 and 48 hours. In addition, the morphology of the biofilm was evaluated by scanning electron microscopy. RESULTS: C. albicans developed biofilms on the surface of all materials tested. Cobalt-chromium alloy showed the lowest density of adhered biofilm, followed by zirconia and titanium. Silicone and resin showed up to 20 times higher density of biofilm. A higher biofilm formation was observed when junctions of materials presented micro-pores or imperfections. CONCLUSIONS: The biofilm formed in the three materials used in the manufacture of abutments and prostheses showed no major differences, being far less dense than in the resins. Two clinical recommendations can be made: to avoid the presence of resins in the subgingival area of implant prostheses and to design prostheses placing cobalt-chromium alloy/ceramic or titanium/ceramic junctions as far as possible from implants

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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.

The role of implant-abutment connection in preventing bacterial leakage: a review.

Osseointegration can be affected by oral conditions; in particular, the micro gap at the implantabutment-connection (IAC) represents a site for dental plaque aggregation favoring bacterial leakage that can increase inflammatory cells at the level of the IAC, causing peri-implantitis. This micro gap, once early colonized, may constitute a bacterial reservoir that could subsequently contaminate fixture's surroundings and interfere with peri-implant tissues health. The aim of this review is to describe, according to the most recent literature, the different kind of implant-abutment connection and their ability to reduce bacterial leakage and thus preventing peri-implantitis. The following database were consulted: Pubmed (n=26), Scopus (n=90), Research gate (n=7) and 123 articles were found. Duplicates were excluded and after reading abstract and titles, those articles that were off topic were also excluded. The remaining ones (n=24) were assessed for full-text eligibility. We excluded 5 articles because they were case reports, 2 because there was no clear reference to the relationship between IAC and bacterial leakage and 2 because they were not pertinent to the argument. Fifteen articles were included in the review. From the review, it is clear that a relationship between the IAC and bacterial leakage exists. All the connections presented an amount of micro-gap and bacterial micro-leakage but conical and mixed connection systems seem to behave better. Moreover, both connections seem to have a better load distribution and the mixed one has anti-rotational properties, very useful during the positioning of the prosthesis.

Efficacy of a new chemical device to minimize microbial contamination along implant-abutment connection: an in vitro study.

Osseointegrated dental implants showed elevated success rates on the long-term treatment in the last ten years. However, the risk of peri-implantitis and implant failure is the main complication of implantology. The presence of a micro gap at the implant-abutment connection (IAC) allows microorganisms to penetrate and colonize the inner part of the implant leading to biofilm accumulation and consequently to peri-implantitis development. Some chemical devices (CD) has been studied to reduce bacterial penetration at IAC level but no one have been demonstrated to be effective for this purpose. Aim of the present study is to evaluate the effectiveness of a new chemical formulation STCX-1, placed in the internal part of dental implants for killing bacteria present in the IAC. To identify the antibacterial power of SXTC-1 at interface between implant-abutment connection, the passage of genetically modified Escherichia coli across IAC was evaluated. A total of eight implants were used (Edierre Implant System, Edierre SpA, Genova, Italy). The inner side of four out of the eight implants were firstly contaminated with few microliters of pure bacteria, subsequently were treated with SXTC-1 for few second and finally, the antibacterial was replaced with Lysogeny Broth (LB) and antibiotics without bacteria. The remaining four implants were not treated with SXTC-1 and just filled with LB with antibiotics. Bacteria viability was determined by measuring their Optical Density (OD) at 600nm. The analysis revealed that, in untreated implants, bacteria grew (internally and externally) for the first 48 hours, but subsequently they started to dye. In treated implants, instead, bacteria grew just in the space surrounding the device suggesting that, even if bacteria were able to get into, they immediately died thanks to the presence of SXTC-1. The STCX-1 liquid formulation have been demonstrated to be an adjuvant CD effective for prevention of of bacterial colonization at IAC level.

Biofilm formation on polyetheretherketone and titanium surfaces.

Objective: Polyetheretherketone (PEEK) is a polymer used in devices in orthopedic and dental rehabilitation. The aim of this in vitro study was to compare biofilm formation by a range of important oral bacterial species on PEEK, blasted PEEK, commercially pure titanium (cp-Ti), and titanium-6 aluminium-4 vanadium (Ti6Al4V). Material and methods: Coin-shaped samples were manufactured, and the surfaces were characterized using optical interferometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and contact angle measurements. Bacterial species of Streptococcus sanguinis, Streptococcus oralis, Enterococcus faecalis, and Streptococcus gordonii were cultured on the four material surfaces for varying amounts of time. Biofilms were quantified following staining with crystal violet. Results: Roughness and contact angle results showed blasted PEEK > PEEK > cp-Ti = Ti6Al4V. There was increased biofilm formation on blasted PEEK by S. sanguinis, S. oralis, and S. gordonii, whereas the bacterial adhesion was similar on PEEK, cp-Ti, and Ti6Al4V. The bacterial growth of E. faecalis was significantly higher on cp-Ti compared with the other three groups. Conclusion: The results, taking into consideration the biofilm formation, suggest that PEEK should perform as well as cp-Ti or TiAl6V4 when used as a dental restorative material.

Iodoform and silver-coated abutments preventing bacterial leakage through the implant-abutment interfaces: In vitro analysis using molecular-based method.

OBJECTIVES: The aim of this in vitro study was to evaluate the effectiveness of an iodoform paste and silver-coated abutments in preventing the microbial colonization and leakage through the implant-abutment interface of morse taper and internal hexagon implants. MATERIAL AND METHODS: Seventy-two implants with morse taper (n = 36) or internal hexagon connections (n = 36) were investigated. Implants were treated with iodoform paste (n = 12), silver-coated abutments (n = 12), or control (n = 12). After saliva incubation, Checkerboard DNA-DNA hybridization was used to identify and quantify up to 43 microbial species colonizing the inner parts of the implants. ANOVA-Type and Wald-Type analyses of variance were used to investigate the relative effects and their interaction. Friedman- Conover test adjusted by Benjamini-Hockberg FDR were performed for pairwise multiple comparisons. Significance was set as p < 0.05. RESULTS: Analyses of variance indicate a significant interaction between connections, antimicrobial treatments, and species. The frequency of contamination was reduced in the implants submitted to the antimicrobial treatments. Iodoform and silver-coated abutments significantly reduced the total microbial counts in the internal hexagon implants. The lower microbial counts were recorded for morse taper implants with silver-coated abutments. CONCLUSIONS: Iodoform paste and silver-coated abutments have influenced the microbial leakage through the implant-abutment interface, by reducing both frequency of contamination and microbial levels. Treatments were not effective in reducing the counts of the target species.

Reusing Titanium Healing Abutments: Comparison of Two Decontamination Methods.

PURPOSE: To assess the amount of contamination remaining on used healing abutments after autoclaving and to compare the effectiveness of two additional decontamination methods. MATERIALS AND METHODS: After autoclaving, a total of 120 used healing abutments were divided equally into three groups: used healing abutments after autoclaving only (group 1); used healing abutments after autoclaving and air-flow polishing (Master Piezon, EMS) using erythritol powder (AIR-FLOW PLUS, EMS) (group 2); and used healing abutments after autoclaving and sodium hypochlorite (NaOCl; 25 g/L) treatment (group 3). Residual contaminants were stained using Phloxine B (400 g/mL), and healing abutments were photographed using a light microscope with digital capture system (Nikon SMZ800). The proportion of stained (ie, contaminated) areas on each healing abutment was then measured using imaging software (ImageJ). The healing abutments were also examined using scanning electron microscopy (SEM). RESULTS: Mean proportion of surface area affected by residual contaminants on the body, top (screwdriver-engaging), and bottom (implant-abutment interface) surfaces for group 1 was 38.2% ± 28.34%, 30.0% ± 19.55%, and 18.7% ± 17.87%, respectively; group 2 showed 3.5% ± 4.90%, 5.3% ± 3.74%, and 5.4% ± 8.49%, respectively; and group 3 showed 0.3% ± 0.16%, 1.9% ± 2.14%, and 0.7% ± 1.02%, respectively. Autoclaving alone was insufficient for successful decontamination, while additional decontamination procedures significantly reduced remaining contaminants. NaOCl was significantly more effective than air polishing. SEM analysis showed no detectable differences in the surface appearance of titanium healing abutments. CONCLUSION: The results show that decontamination of used healing abutments is achievable, thus strengthening the feasibility of reusing healing abutments.

Formation of biofilm on various implant abutment materials.

The characteristics of prosthetic implant components, such as the type, material, and surface roughness of abutments, can affect biofilm formation. Since an ideal abutment surface for the reduction of bacterial adhesion has yet to be found, this in vitro study aimed to quantify biofilm formation on laser-treated titanium, zirconia, and titanium surfaces. Sterile titanium, zirconia, and laser-treated titanium discs were placed in sterile 48-well plates. Biofilm formation was induced by adding sterilized, unstimulated human saliva and suspensions of Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and Prevotella intermedia (Pi) to the wells. Viable bacteria in the biofilm were quantified with real-time polymerase chain reaction in conjunction with propidium monoazide. The disc material, the type of bacteria, and their interactions had significant effects on the bacterial counts. On all surfaces, the Pg count was significantly higher than both the Pi and Aa counts (P = 0.0001). The highest count of periodontal pathogens was found on laser-treated surfaces. The second highest and the lowest counts were found on zirconia and titanium surfaces, respectively.

Biocompatibility and antibacterial properties of zirconium nitride coating on titanium abutments: An in vitro study.

Improving soft tissue attachment and reducing bacterial colonization on titanium abutments are key factors for the long-term maintenance of healthy soft and hard peri-implant tissues. This in vitro study was conducted to compare the biocompatibility and antibacterial activity of four different surfaces: uncoated Ti6Al4V, anodized, and coated with titanium nitride or zirconium nitride. Surface topography was investigated with a high-resolution system for measuring surface finishes. Human gingival fibroblast (HGF) adhesion and proliferation were examined using MTT assay, Scanning Electron Microscopy (SEM) imaging, immunofluorescence analysis and real-time PCR for selected target genes. The hemolysis and AMES tests were performed to assess the chemical compounds' blood compatibility and mutagenic potential, respectively. Antibacterial activity was tested against five bacterial strains isolated from the oral cavity (Streptococcus salivarius, S. sanguinis, S. mutans, S. sobrinus, S. oralis), and the percentage of dead bacteria was calculated. Roughness measurements confirmed a substantial similarity between the surfaces and their compatibility with clinical applications. MTT assay, SEM analysis and immunofluorescence staining showed adhesion and proliferation of HGFs cultured on all the examined surfaces. PCR confirmed that HGFs produced extracellular matrix components efficiently on all the surfaces. No hemolytic activity was detected, and the AMES test confirmed the surfaces' clinical safety. For all tested bacterial strains, biofilms grown on the zirconium nitride surface showed a higher percentage of dead bacteria than on the other disks. The titanium nitride surface inactivated bacterial biofilms, too, but to a lesser extent.

Effects of Taper Angle and Sealant Agents on Bacterial Leakage Along the Implant-Abutment Interface: An In Vitro Study Under Loaded Conditions.

PURPOSE: The aim of this study was to compare the bacterial leakage of conical internal connection implants with different taper angles (5.4, 12, 45, and 60 degrees) and examine the efficiency of a disinfectant agent and a silicone sealant agent in the prevention of bacterial leakage under loaded conditions. MATERIALS AND METHODS: Twenty-one implant-abutment connections were studied from each implant system (Ankylos Implants, Dentsply; Bego Semados S Implants, Bego; Trias Implants, Servo-Dental; DTI Implants, DTI), for a total of 84 implants. Each system's implants were divided into three groups as follows: unsealed (control), 2% chlorhexidine gel-sealed, or silicone-sealed (n = 7 for each group). The insertion torque was applied to each abutment screw according to the manufacturers' recommendation. The specimens were partially immersed in an 8-mm E faecalis suspension. A cyclic load of 50 N was applied for a total of 500,000 cycles at 1 Hz to the specimens. Following disconnection of dental implants and abutments, microbial samples were taken from the inner threaded surface of the implants, plated, and counted under appropriate conditions. RESULTS: There were no statistically significant differences in frequency of bacterial leakage and leaked bacterial counts among the four types of connections in all groups (P > .05). The statistically significant differences were found between sealant agents and control groups in four different connection types in terms of the amount of leaked bacteria (P < .05). There was no significant difference between the amount of leaked bacteria for four connection types when comparing the chlorhexidine and silicone sealant agents (P > .05). CONCLUSION: Differences in taper angles in the internal conical connections had no significant effect on leaked bacterial counts or the frequency of bacterial contamination under dynamic loading. The application of 2% chlorhexidine gel or a silicone sealant can reduce the leaked bacterial counts and reduce the frequency of bacterial leakage.

Reuse of Implant Healing Abutments: Comparative Evaluation of the Efficacy of Two Cleaning Procedures.

PURPOSE: To compare the efficacy of two systems in cleaning used healing abutments (HAs). MATERIALS AND METHODS: A total of 60 used HAs were randomized into two groups: one treated with an automatic cleaning system, and the other with conventional decontamination procedures. After sterilization and staining, the HAs were microscopically analyzed and underwent a cellular adhesion in vitro assay. RESULTS: Contaminated areas were observed with different frequencies in the two groups (3.6% test; 78.2% control; P < .001). In vitro assay showed a uniform cell distribution in test HAs, while areas of debris without adhering cells were a common finding in the control HAs. CONCLUSION: Further studies investigating the chemical composition and clinical influence of biologic remnants are necessary before considering reusing HAs.

Bacterial microleakage at the abutment-implant interface, in vitro study.

INTRODUCTION: In implant rehabilitation, a microspace is created at the abutment-implant interface (AII). Previous research has shown that oral microbiome can proliferate in this microspace and affect periimplant tissues, causing inflammation in peri-implant tissues. Preventing microbial leakages through the AII is therefore an important goal in implantology. OBJECTIVE: To determine the presence of marginal bacterial microleakage at the AII according to the torque applied to the prosthetic implant in vitro. MATERIAL AND METHODS: Twenty-five Ticare Inhex internal conical implants (MG Mozo-Grau, Valladolid, España) were connected to a prosthetic abutment using torques of <10, 10, 20, 30, and 30 N and then sealed. The samples were submitted to cycles of occlusal loads and thermocycling, then one sample of each group was observed by micro TC, while the rest were mounted on devices according to the bacterial leakage model with Porphyromonas gingivalis. RESULTS: Bacterial leakage was observed only in the <10 and 10 N torque samples, and the same groups presented poor abutment/implant adjustment as determined by micro-CT. CONCLUSION: The different torques applied to the abutment-implant system condition the bacterial leakage at the implant interface. No microleakage was observed at 20 and 30 N.

Evaluation of Candida Albicans biofilm formation on various parts of implant material surfaces.

AIMS: Candida albicans adhesion to any oral substrata is the first and essential stage in forming a pathogenic fungal biofilm. In general, yeast cells have remarkable potential to adhere to host surfaces, such as teeth or mucosa, and to artificial, non-biological surfaces, such as dental materials. C. albicans adhesion to denture materials is widely recognized as the main reason for the development of stomatitis. This study compared the susceptibility of different parts of the implant system with C. albicans adhesion. MATERIAL AND METHODS: Each material maintained contact with C. albicans suspension, and biofilm formations around the implant materials were evaluated. To evaluate the biofilm formation, the XTT technique and scanning electron microscopy (SEM) were used. RESULTS: In general, a fine biofilm layer of C. albicans species was found on the surface of all examined materials. However, when examining the SEM images, candidal growth was significantly lower on the surfaces of the gingival former, abutment, and machined surface implant samples. According to the colorimetric assay (XTT), the gingival former samples revealed the lowest quantity of biofilms formed (median XTT value, 0.0891) (P < 0.001). The abutment and machined surface implant samples had low XTT values with similar values. The highest median colorimetric XTT values (0.1741), significantly higher than those of the other materials (P < 0.001), were for the bone level implant samples. CONCLUSIONS: This finding emphasizes implant treatment would be chosen complacency in patients who are prone to oral candidosis, medically compromised patients under immunosuppression, and patients with tumor who are being treated with chemotherapy or radiation.

Genome analysis and clinical implications of the bacterial communities in early biofilm formation on dental implants restored with titanium or zirconia abutments.

This cross-sectional study aimed to identify and quantify up to 42 target species colonizing the early biofilm of dental implants restored with titanium or zirconia abutments. A total of 720 samples from 20 healthy individuals were investigated. Biofilm samples were collected from the peri-implant sulci, inner parts of implants, abutment surfaces and prosthetic crowns over a functioning period of 30 days. Checkerboard DNA-DNA hybridization was used for microbial detection and quantitation. Clinical characteristics (probing depth, bleeding on probing, clinical attachment level and marginal bone loss) were also investigated during the monitoring period. Genome counts were low at the implant loading time point for both the abutment materials, and increased over time. Both the titanium and the zirconia groups presented similar microbial counts and diversity over time, and the microbiota was very similar to that colonizing the remaining teeth. Clinical findings were consistent with a healthy condition with no significant difference regarding marginal bone loss between the two materials.

Onset, progression and resolution of experimental peri-implant mucositis at different abutment surfaces: A randomized controlled two-centre study.

OBJECTIVES: To assess the onset, progression and resolution of experimentally induced peri-implant mucositis lesions at abutments with different microstructures in humans. MATERIAL & METHODS: In a randomized, controlled, interventional two-centre study, a total of 28 patients had received 28 target implants and were randomly allocated to either partially microgrooved (test) or machined (control) healing abutments. The study was accomplished in three phases, including a wound healing period (WH) following implant placement (12 weeks), a plaque exposure phase (EP-21 days) and a resolution phase (RP-16 weeks). Clinical (e.g. bleeding on probing-BOP), immunological (MMP-8) and microbiological (DNA counts for 11 species) parameters were evaluated. RESULTS: The incidence of peri-implant mucositis at EPd21 was comparable in both test and control groups (60.0% versus 61.5%), but markedly lower at control abutments after a nonsurgical treatment and reconstitution of oral hygiene measures at RPw16 (46.7% versus 15.4%). At any follow-up visit (i.e. EP and RP), clinical parameters, MMP-8 levels and DNA counts of major bacterial species were not significantly different between both groups. CONCLUSION: The onset, progression and resolution of experimental peri-implant mucositis lesions were comparable in both groups.

Oral bacterial colonization on dental implants restored with titanium or zirconia abutments: 6-month follow-up.

OBJECTIVE: This investigation aimed to characterize in a 6-month follow-up the microbial profile of implants restored with either titanium or zirconia abutments at the genus or higher taxonomic levels. METHODS: Twenty healthy individuals indicative for implant-retained single restorations were investigated. Half of participants were restored with titanium and half with zirconia abutments. Biofilm was collected from the implant-related sites after 1, 3, and 6 months of loading. The 16S rDNA genes were amplified and sequenced with Roche/454 platform. RESULTS: A total of 596 species were identified in 360 samples and grouped in 18 phyla and 104 genera. Titanium- or zirconia-related sites as well as teeth showed similar total numbers of operational taxonomic units (OTUs) colonizing surfaces over time. Firmicutes, Proteobacteria, Fusobacteria, Bacteroidetes, and Actinobacteria were the most prevalent phyla with significant differences between different surfaces and time point. Unclassified genera were found in lower levels (1.71% up to 9.57%) on titanium and zirconia samples when compared with teeth, with no significant differences. CONCLUSION: Titanium- and zirconia-related surfaces are promptly colonized by a bacterial community similar to those found in the remaining adjacent teeth. Results suggest a selective adhesion of different bacterial genotypes for either titanium or zirconia surfaces. Data also indicate a significant interaction between the relative effects taxa, time point, and sampling site. CLINICAL RELEVANCE: The present study disclosed a wider spectrum of microorganisms colonizing either titanium- or zirconia-related microbiomes in very early stage of implant colonization, revealing differences and suggesting a probably specific mechanism for selective bacterial adhesion.

Association Between Implant-Abutment Microgap and Implant Circularity to Bacterial Leakage: An In Vitro Study Using Tapered Connection Implants.

PURPOSE: The aim of this study was to evaluate the microgap between the abutment and implant as well as the circularity of implant platforms and associating conformational errors with bacterial microleakage in tapered connection implant systems. MATERIALS AND METHODS: Four brands of implants with a tapered abutment connection were tested. Bacterial leakage was assessed using 0.3 µL of Escherichia coli suspension inoculated into the abutment screw chamber of the implants, which were then torqued and incubated at 37°C for 14 days. All specimens used for the microbiologic experiment were then cut lengthwise, and the microgap was measured at three points on each side of the sample using scanning electron microscopy (up to 5,000× magnification). Microtomography was used to assess implant platform circularity to validate the microscopic findings qualitatively. RESULTS: Two samples from the Nobel Biocare system, four from the Ankylos (Dentsply) system, four from the Neodent (Straumann) system, and five from the Conexão system were positive for bacterial leakage, with no significant difference between groups. The Neodent system had the highest mean microgap values (5.84 ± 9.83 µm), followed by the Nobel Biocare systems (5.17 ± 4.10 µm), Ankylos (3.47 ± 3.28 µm), and Conexão (2.72 ± 3.19 µm), with no significant difference between systems. All systems showed conformational errors of circularity on microtomography images. CONCLUSION: The tapered connection systems evaluated herein were not able to halt bacterial leakage, nor were they free from conformational errors.

Bidirectional flux of fluids and microbiota at implant-abutment connection of FMD Storm implant system: an in vitro stud y using RT-PCR.

The purpose of the present microbiological study was to evaluate bacterial leakage at implant-abutment connection level of a new type of implant (Storm implant (FMD, Falappa Medical Devices®, Rome, Italy) using Real-Time Polymerase Chain Reaction (RT-PCR). This implant presents a polygonal external implantabutment connection with a geometry that provides a hex on which engage complementary abutments. To identify the capability of the implant to protect the internal space from the external environment, the passage of genetically modified Escherichia coli across implant-abutment interface was evaluated. Four Storm implants (FMD, Falappa Medical Devices®, Rome, Italy) were immerged in a bacterial culture for 24 h and bacteria amount was measured inside implant-abutment interface with Real-time PCR. Bacteria were detected inside all studied implants, with a median percentage of 15% for P. gingivalis and 14% for T. forsythia. Our results are similar to those reported in the English literature. Additional studies are needed to explore the relationship in terms of microbiota between the internal implant and implant-prosthetic connection. In addition, the dynamics of internal colonization needs to be thoroughly documented in longitudinal in vivo studies. As a result, microbial leakage along the implant abutment interface was acceptable and considered the most probable explanation for peri-implantitis.

Bacterial colonization of the implant-abutment interface of conical connection with an internal octagon: an in vitro study using real-time PCR.

Bacterial leakage at the implant-abutment connection of a two-piece implant system is considered the main cause of peri-implantitis. Prevention of bacterial leakage at the implant-abutment connection is mandatory for reducing inflammation process around implant neck and achieving bone stability. Micro-cavities at implant-abutment connection level can favour bacterial leakage, even in modern two-piece implant systems. The conical connection with an internal octagon (CCIO) is considered to be more stable mechanically and allows a more tight link between implant and abutment. As P. gingivalis and T. forsythia penetration might have clinical relevance, it was the purpose of this investigation to evaluate molecular leakage of these two bacteria in a new two-implant system with an internal conical implant-abutment connection with internal octagon (Shiner XT, FMD Falappa Medical Devices S.p.A. Rome, Italy). To verify the ability of the implant in protecting the internal space from the external environment, the passage of genetically modified Escherichia c oli across implant-abutment interface was evaluated. Four Shiner XT implants (FMD, Falappa Medical Devices®, Rome, Italy) were immerged in a bacterial culture for 24 h and bacteria amount was measured inside implant-abutment interface with Real-time PCR. Bacteria were detected inside all studied implants, with a median percentage of 6% for P. gingivalis and 5% for T. forsythia. Other comparable studies about the tightness of the tested implant system reported similar results. The gap size at the implant-abutment connection of CCIOs was measured by other authors discovering a gap size of 1­2µm of the AstraTech system and of 4µm for the Ankylos system. Bacterial leakage along implant-abutment connection of cylindrical and tapered implants, Shiner XT, (FMD Falappa Medical Devices S.p.A. Rome, Italy) showed better results compared to other implants. Additional studies are needed to explore the relationship in terms of microbiota of the CCIO. In addition, the dynamics of internal colonization needs to be thoroughly documented in longitudinal in vivo studies.