Peri-implant Sulcus Research Articles

16s metagenomic sequencing and analysis of plaque sample around dental implants using nanopore sequencing platform - A preliminary report

ABSTRACT Aim: The aim of the study was to evaluate the peri-implant microbiome in relation to the dental implant status such as plaque status, peri-implant sulcus depth, and bleeding on probing. Materials and Methods: Peri-implant subgingival biofilm samples were collected from three patients who received laser micro-grooved implants 18 months back, with paper points, and analyzed using 16s metagenomic sequencing and analyzed using nanopore sequencing platform. The microbial profile analysis based on the DNA classification of the microbial samples was done using the Burrows–Wheeler transform and Ferragina-Manzini index and optimized for metagenomic classification. Pavian was used to estimate and explore the taxonomic content. Results: The study results suggest that the microbiome diversity and species abundance showed high proportions of Veillonella, Streptococcus, Selenomonas, Fusobacterium, which could be considered as preliminary data for three different patients, one being diabetic, the other a smoker, and healthy control. Conclusions: The diabetic patients had predominantly Streptococcus (10%), whereas the smokers had predominantly Veillonella (18%) and Streptococcus (14%). The peri-implant sulcus region of diabetics and smokers shows a predominance of Gram-negative bacteria.

ALTERATIONS OF THE OSTEOINTEGRATION MARKERS AFTER DENTAL IMPLANTATION

The stability of the implant depends significantly on the process of osseointegration between the bone and the implant. The cellular and molecular mechanisms of the osseointegration process have not yet been fully established and require further research in this direction.The aim of the study was to study the markers of the processes of osteointegration after dental implantation. The study was conducted on 31 patients who underwent implantation at the base of "Unident" and "A1" clinics.We collected gingival crevicular fluid (GCF) and peri-implant sulcus fluid (PISF) from patients before implantation and 1 month after implantation. In PISF and GCF fluids, bone markers (osteoprotegerin (OPG), osteocalcin (OC), osteopontin (OPN), bone-specific alkaline phosphatase (bALP)) were determined by the immunoenzymatic method.The PISF and GCF were collected using standardized paper strips (Periopaper, no.593525), which were placed at the entrance of the grooves of the implant and/or healthy teeth at a standardized depth of 1 mm for 30 seconds. The content of the OPG, OC and bALP in the PISF fluid 1 month after implantation does not change statistically significantly compared to the initial values in the GCF fluid (p=0.74; p=0.44; p=0.69). 1 month after the implantation, the content of OPN in PISF fluid increased by 133% compared to its content in GCF fluid before implantation (p<0.001).According to the study results, the OPN content in the PISF fluid increases sharply 1 month after the implantation. This parameter can be used as a marker of implant integration with living bone and bone wound healing.

Electrical Potentiometry with Intraoral Applications.

Dental implants currently in use are mainly made of titanium or titanium alloys. As these metallic elements are immersed in an electrolytic medium, galvanic currents are produced between them or with other metals present in the mouth. These bimetallic currents have three potentially harmful effects on the patient: micro-discharges, corrosion, and finally, the dispersion of metal ions or their oxides, all of which have been extensively demonstrated in vitro. In this original work, a system for measuring the potentials generated in vivo is developed. Specifically, it is an electrogalvanic measurements system coupled with a periodontal probe that allows measurement of the potentials in the peri-implant sulcus. This device was tested and verified in vitro to guarantee its applicability in vivo. As a conclusion, this system is able to detect galvanic currents in vitro and it can be considered capable of being employed in vivo, so to assess the effects they may cause on dental implants.

Simultaneous presence of Mycoplasma salivarium and Tannerella forsythia in the implant sulcus after lateral augmentation with autogenous root grafts is associated with increased sulcus probing depth.

To characterize a potential pathogenic role of Mycoplasma salivarium and bacterial co-detection patterns on different implant augmentation types. 36 patients were non-randomly assigned to autogenous lateral alveolar ridge augmentation with either cortical autogenous bone blocks, or healthy autogenous tooth roots or non-preservable teeth. Mucosal inflammation was assessed by probing pocket depth (PD) at all sampling sites and by bleeding on probing (BOP) in a subset of sampling sites, and standardized biofilm samples were obtained from the submucosal peri-implant sulcus and sulcus of a contralateral tooth at two times (t1 after implant placement; t2 after six months). Seven bacterial species were quantified using Taqman PCR. Mucosal inflammation did not differ between augmentation groups, but peri-implant sulci showed increased abundance of M. salivarium after augmentation with autogenous tooth roots lasting for at least six months (t1 p = 0.05, t2 p = 0.011). In M. salivarium-positive samples, Tannerella forsythia was correlated with PD (R = 0.25, p = 0.035) This correlation was not observed in M. salivarium-negative samples. Compared to all other samples, PD was deeper in co-detection (i.e., simultaneous M. salivarium and T. forsythia) positive samples (p = 0.022). No association of single or co-detection of bacteria with BOP was observed. Presence of M. salivarium in peri-implant sulci varies with augmentation method and is associated with increased PD but not BOP. A potential causal role of M. salivarium in inflammation through a mechanism involving co-presence of T. forsythia requires further study.

Microbiota analysis of peri-implant mucositis in patients with periodontitis history

ObjectivesTo investigate the bacterial diversity in peri-implant plaques and the effect of periodontitis history on the occurrence of peri-implant mucositis.Materials and methodsThree groups of subgingival plaques were collected from peri-implant sulci in the first molar area. The three groups included healthy implants in patients without periodontitis (NH implant), healthy implants in patients with periodontitis history (PH implant), and peri-implant mucositis implants in patients with periodontitis history (PM implant). Subgingival plaques in periodontal pockets of contralateral natural first molars were also collected. Bacterial DNA was extracted and the V4 region of the 16S rDNA sequence was amplified and sequenced on an Illumina HiSeq platform. The operational taxonomic units obtained from amplicon sequencing were used to analyze the prevalence and identity of bacteria based on public databases and advanced techniques.ResultsAnalysis of similarities indicated a significant difference in bacterial structures between the NH implant and PM implant groups. Additionally, a significantly higher relative abundance of the genera Actinomyces and Streptococcus was found in the samples of the NH implant group. The genera Fusobacterium and Prevotella could be considered as potential biomarkers for peri-implant mucositis. Moreover, more gram-negative anaerobic bacteria (Porphyromonas and Prevotella) were detected in the samples from patients with periodontitis history.ConclusionsThe increased accumulation of Fusobacterium and Prevotella is associated with a higher risk of peri-implant mucositis. In addition, patients with periodontal history may be more likely to develop peri-implant mucositis.Clinical relevanceThe increase in periodontal pathogens and the decrease in health-associated bacteria in patients with periodontitis history may be more likely to develop peri-implant mucositis. These results provide a bacteriological basis for the prevention and treatment of peri-implant mucositis in patients with periodontitis history.

Biome-microbiome interactions in peri-implantitis: A pilot investigation.

Dental implants replace missing teeth in at least 100 million people, yet over one million implants fail every year due to peri-implantitis, a bacterially induced inflammatory disease. Our ability to treat peri-implantitis is hampered by a paucity of information on host-microbiome interactions that underlie the disease. Here, we present the first open-ended characterization of transcriptional events at the mucosal-microbial interface in the peri-implant crevice. We simultaneously sequenced microbial and human mRNA from five pairs of healthy and diseased implants from the same patient and used graph theoretics to examine correlations between microbial and host gene expression in the peri-implant crevice. We identified a transcriptionally active peri-implant microbiome surrounding healthy implants. Microbial genes encoding phenylalanine, tyrosine, and tryptophan biosynthesis, cysteine, methionine, arginine, proline, and histidine metabolism correlated to human genes encoding cell development, metabolism, morphogenesis, adhesion, gap junctions, cell-cell signaling, and immunoinflammatory pathways, suggesting a role for commensals in protecting epithelial integrity. In disease, we found 4- to 200-fold upregulation in microbial genes encoding biofilm thickness, heme transport and utilization, and Gram-negative cell membrane synthesis. These genes correlated with mucosal zinc finger proteins, apoptosis, membrane transport, inflammation, and cell-cell communication. Within the limitations of a small sample size, our data suggest that microbial dysbiosis in the peri-implant sulcus might promote abandonment of host-bacterial transactions that dictate health and instead drive a move towards chronic programming of a non-healing wound.

Role of antimicrobial photodynamic therapy in reducing subgingival oral yeasts colonization in patients with peri-implant mucositis

The aim was to assess the role of antimicrobial photodynamic therapy (aPDT) in reducing subgingival oral yeasts colonization (OYC) in patients with peri-implant mucositis (PIM). Patients diagnosed with PIM were included. Patient demographics were recorded and implant placement and prosthetic rehabilitation protocols were retrieved from patients' records. Peri-implant clinical parameters (modified plaque index [mPI], modified bleeding index [mBI] probing depth [PD]) and subgingival OYC and were assessed using standard techniques. All patients were randomly divided into test- and control-groups. In the test-group, patients underwent mechanical debridement (MD) of implant surfaces and supra and sub-gingival peri-implant sulci peri-implant immediately followed by a single session of aPDT. In the control-group, patients underwent MD alone. Peri-implant clinical parameters and OYC were re-assessed at 3-months' follow-up. Sample-size estimation was done on data from a pilot investigation and group-comparisons were done using the paired t- and Mann Whitney U-tests. Correlation between age, mPI, mBI, PD and OYC at baseline and 3-months' follow-up was assessed using regression analysis models. A statistically significant difference between the groups was recorded when P-values were less than 0.01. Thirty-four individuals (17 and 17 in the test- and control groups, respectively) were included. There was no significant difference in the mean age, scores of mPI, mBI, PD and OYC among patients in the test- and control-groups at baseline. At 3-months of follow-up, there was a statistically significant reduction in scores of mPI (P<0.001), mBI (P<0.001), PD (P<0.001) and OYC (P<0.001) among patients in the test- compared with the control-groups. There was no significant correlation between age, mPI, mBI, PD and OYC in both groups. In the short term, a single session of aPDT as an adjunct to MD is effective in reducing peri-implant soft tissue inflammation and OYC in patients with PIM.

A Systematic Review of Cementation Techniques to Minimize Cement Excess in Cement-Retained Implant Restorations.

Background: The most used types of retention of implant-supported prostheses are screw-retained or cement-retained restorations. The advantages and disadvantages of both have been identified by various authors over the years. However, cement-retained implant crowns and fixed partial dentures are among the most used types of restorations in implant prostheses, due to their aesthetic and clinical advantages. When cemented prostheses are made on implants, the problem of cement residues is important and often associated with biological implant pathologies. The objective of this research was to establish to what extent the techniques to reduce excess cement really affect the volume of cement residues. Materials and Methods: This review was written following the PRISMA statement; a detailed search was carried out in three different electronic databases—PubMed, Scopus, and Cochrane Library. The inclusion criteria were prospective clinical studies, with at least 10 participants per group, and with at least 6 months of the follow-up period. Results: There have been many proposals for techniques supposed to reduce the amount of excess cement in the peri-implant sulcus and on the prosthetic components, but of these, which are exceptional in their in vitro capabilities, very few have been clinically validated, and this represents the real limitation and a great lack of knowledge regarding this topic. Three articles met the inclusion criteria, which were analyzed and compared, to obtain the information necessary for the purposes of the systematic review. Discussion: Extraoral cementation can reduce the excess cement, which, after a normal excess removal procedure, is, nevertheless, of such size that it does not affect the possibility of peri-implant pathologies developing. All these studies concluded that a small amount of cement residue is found in the gingival sulcus, and using eugenol-free oxide cements, the residues were only deposited on the metal surfaces, with a better peri-implant tissues health. Conclusion: Despite the limitations of this study, it was possible to carefully analyze these characteristics and obtain valuable suggestions for daily clinical practice. Resinous cements are considered, due to the free monomers present in them, toxic for the soft tissues. The provisional zinc-oxide cements, also eugenol-free, represent the ideal choice. The different grades of retentive forces provided by these cements do not seem to have clinical effects on the decementation of restorations.

Microbiological Profile in Periodontitis and Peri-Implantitis: A Systematic Review.

Understanding the microbiological makeup of peri-implant biofilm could contribute to the discovery of focused treatment strategies, improving the outcome of peri-implantitis management. However, the bacterial profile in diseased periodontal and peri-implant sulci is still unclear. This systematic review aims to analyze the microbiological similarities and differences between diseased periodontal and peri-implant sulci based on the available literature evidence. A thorough search was conducted in electronic databases such as PubMed, Google Scholar, and Cochrane, as well as a manual search employing the eligibility criteria. After a thorough review, studies evaluating the microbial composition acquired from plaque samples obtained from patients with diseased periodontal and peri-implant sulci were chosen. The selected 8 studies evaluated the differences in microbial profile in periodontitis and peri-implantitis. Five studies found a statistically significant variation in the microbial profile between diseased periodontal and peri-implant sulci, while in one study, no changes in the microbiology of inflammatory peri-implant and periodontal sites were observed. In one of the two in situ studies, the structure of the transcription level and core species was different in peri-implantitis, whereas the other in situ study found that the 16S rRNA-based bacterial profile of both the diseases were different, while the functional genes, taxonomic, and virulence factor mRNA profiles were identical. According to existing studies, significant differences in the biofilm composition of diseased periodontal and peri-implant sulci were observed. Therefore, periodontitis and peri-implantitis have diverse microbial characteristics.

The effect of chlorhexidine gluconate chips on clinical status of peri-implant mucosa and plaque formation on healing abutments following single-stage implant surgeries

An experimental study was designed to evaluate the effect of chlorhexidine gluconate chips on clinical status of peri-implant mucosa and plaque formation on healing abutments following single-stage implant surgeries. Twenty-eight single-stage implant sites were grouped into 14 test and control sites. The study commences from the time of suture removal following surgery, designated as day 0. Chlorhexidine chip insertion into peri-implant sulcus in test sites was done on day 0, 10, and 20. Peri-implant crevicular fluid was collected on day 0, 10, 20, and 30 for biochemical estimation of aspartate aminotransferase (AST). The modified sulcus bleeding index (mBI) score was obtained in both test and control sites on day 10, 20, and 30. On day 30, all the healing abutments were unscrewed and sent for stereomicroscopic analysis to assess the plaque formation on its surface. Statistically significant difference was not observed in AST levels and mBI in both test and control groups in various time intervals. In the stereomicroscopic assessment of healing abutment, mild grade of plaque accumulation was seen in three samples in test group, one sample in control group, and severe grade was seen in six samples in test group and nine samples in the control group. Inflammatory condition of peri-implant mucosa and plaque retentive properties on healing abutment surface were found to have reduced with the usage of chlorhexidine gluconate chips. However, the study failed to establish a statistically significant correlation of these observations.

PERI-IMPLANTITIS- TIPS IN SURGICAL APPROACH

Bacterial colonization of the peri-implant sulcus, development of inflammation of the soft peri-implant tissues, followed by progressive loss of the peri-implant bone results in &nbsp;periimplantits development and subsequent implant failure. The aim of this case study is to prove that successful treatment of peri-implantitis integrates conservative and surgical approach with the accent on decontamination of the implant surface, complete elimination of microorganisms and their toxins, stabilization of progressive bone loss and regeneration of bone tissue.&nbsp;Case report :&nbsp;In this paper initial and surgical treatment of a periimplant case of 43 years old, non-smoker, in good general health is described. A nonsurgical periodontal supportive therapy was firstly conducted to reduce the inflammation, followed by the surgical treatment of the defect. After mechanical and chemical decontamination with chlorhexidine 0.2%, a regenerative approach consisting in the application of bovine bone mineral (Cerabone) and a CTG membrane&nbsp; was performed. An antibiotic therapy was associated with the treatment according to molecular analysis findings for periodonthopatogenic bacteria. The decision for following the newest up-dates of the surgical protocols for periimplantitis results in predictable clinical improvement in the cases with periimplantitis.&nbsp; &nbsp;Keywords:&nbsp;periimplantits, GBR, CTG.

The Effect of Peri-Implant Disease on Oxidative Stress Markers Levels in Peri-Implant Sulcus Fluid: A Cross-Sectional, Pilot Study

Background: Peri-implant diseases are inflammatory diseases as periodontal disease. An array of oxidative stress markers has been examined in the disease and health of the periodontal tissues. The purpose of the study was to test whether peri-implant conditions have an impact on the peri-implant sulcus fluid oxidative stress markers.Materials and Methods: A total of 44 participants were included in the study. Collected samples divided 3 groups, 14 samples for healthy implants; 15 samples for peri-implant mucositis; and 15 samples for peri-implantitis. In clinical periodontal examination, plaque index (PI), modified bleeding index (mSBI), probing bleeding (BOP), probing pocket depth (PPD), gingival index (GI), modified plaque index (MPI) were measured. Peri-implant sulcus fluid (PISF) samples were collected for evaluating and measuring biochemical analysis of total oxidant status (TOS) and total antioxidant capacity (TAOC) and oxidative stress index (OSI).Results: The TOS level in PISF was statistically significantly higher in the peri-implantitis when compared to the healthy group (p=0.041). There was no statistically significant difference (p&amp;gt;0.05) between groups in terms of TAOC and OSI parameters.Conclusions: As a result of the current study, it can be said that, due to its inflammatory character, peri-implantitis can increase total oxidant status (TOS) in peri-implant sulcus fluid (PISF). Multicentered research is needed to explain which immunological mechanism triggers the oxidative system in peri-implantitis in order to understand the potential role of oxidative stress markers in peri-implant inflammation.

The influence of laser-microgrooved implant and abutment surfaces on mean crestal bone levels and peri-implant soft tissue healing: a 3-year longitudinal randomized controlled clinical trial

PurposeThe study aimed to compare clinical and radiographic parameters of peri-implant site of laser-microgrooved implants with either laser-microgrooved or regular machined prosthetic abutment post 3 years of early loading.MethodTwenty edentulous sites of systemically and periodontally healthy individuals were allocated into two groups in this prospective, two-armed, randomized double-blinded clinical trial in 1:1 ratio, wherein each site received laser-microgrooved implants with either laser-microgrooved or machined prosthetic abutments. Outcome measures included full-mouth plaque (FMPS%) and bleeding score (FMBS%), site-specific plaque (SPS%) and bleeding score (SBS%), peri-implant sulcus depth (PISD mm), and mean crestal bone loss (MCBL mm) evaluated at baseline (6 weeks), 1 and 3 years post-early loading. Mean and standard deviation of all parameters were estimated, between groups and at different time points using independent and paired t-test, respectively, Normality was checked using Kolmogorov–Smirnov test and Shapiro–Wilk test, P value ≤ 0.05 was considered as statistically significant.ResultsThree-year follow-up of test group showed statistically significant reduction in SPS, SBS, PISD (P value ≤ 0.001). The MCBL reduced from 1.93 mm to 0.61 mm (P value ≤ 0.001); in other words, a bone gain of 0.15 mm was obtained in the test group.ConclusionWithin the limitations of the present study, laser-microgrooved implants loaded with laser-microgrooved prosthetic abutments showed superior results clinically and radiographically when compared to loading with machined abutments.

Impact of design elements of the implant supracrestal complex (ISC) on the risk of peri-implant mucositis and peri-implantitis: A critical review.

The aim of this review was to investigate the evidence correlating the emergence profile (EP) and emergence angle (EA), peri-implant tissue height, implant neck design, abutment and/or prosthesis material, retention and connection types with risk of peri-implant mucositis and peri-implantitis. Seven focus questions were identified, and seven electronic search queries were conducted in PubMed. Human studies reporting on bleeding on probing, probing depth or case definitions of peri-implant mucositis and peri-implantitis were included. Emerging evidence with bone-level implants suggests a link between EA combined with convex EP and peri-implantitis. Depth of the peri-implant sulcus of ≥3mm is shown to be reducing the effectiveness of treatment of established peri-implant mucositis. Modification of the prosthesis contour is shown to be an effective supplement of the anti-infective treatment of peri-implant mucositis. Limited evidence points to no difference with regard to the risk for peri-implant mucositis between tissue- and bone-level implants, as well as the material of the abutment or the prosthesis. Limited evidence suggests the use or not of prosthetic abutments in external connections and does not change the risk for peri-implantitis. Literature with regard to prosthesis retention type and risk for peri-implantitis is inconclusive. Limited evidence indicates the involvement of EA, EP, sulcus depth and restricted accessibility to oral hygiene in the manifestation and/or management of peri-implant mucositis/peri-implantitis. Conclusions are limited by the lack of consensus definitions and validated outcomes measures, as well as diverse methodological approaches. Purpose-designed studies are required to clarify current observations.

Optimization of the dental implantation protocol in patients with partial secondary edentulousness and vitamin D deficiency

Relevance. The processes of osseointegration in the area of dental implant placement are accompanied by the development of reactions associ-ated with inflammation and activation of local immune processes in peri-implant tissues. Vitamin D preparations can have a significant local effect on the cells of the innate immune defense of the periodontal tissues.The aim of this work is to study the effectiveness of local application of vitamin D on the immune status of the peri-implant sulcus in rehabilitation of patients with partial secondary edentulous and chronic periodontitis by the method of dental implantation.Materials and methods.Determination of the content of biomarkers (IL-1RA, MCP-1, VEGF, TGF-β1, sTNFR) in the crevicular fluid before the installation of implants and the peri-implantation furrow fluid was carried out by the method of enzyme-linked immunosorbent assay using commercial kits «Vector Best» reagents after 3 and 6 months after surgery. The assessment of the state of the bone tissue was carried out using the Orthopantomograph tm OP300 apparatus (KAVO Dental, Germany). Vitamin D has been used topically at a therapeutic dosage.Results.Vitamin D, by reducing Th-1 and Th-17 cell proliferation and differentiation, blocks the activity of the immune-inflammatory process that occurs during implant placement.Conclusion. Application of colecalciferol in patients with moderate periodontitis leads to the activation of the production of immunoregulatory cyto-kines by the cellular structures of the peri-implantation furrow and can be used in combination with the traditional protocol in this category of patients.

Evaluation of Peri-implant Crevicular Fluid Matrix Metalloproteinase-8 levels of flapped vs. flapless dental implants: A prospective study

Objectives: The objective of this study was to compare the placement of flapped vs. flapless dental implants utilizing clinical and immunological parameters. Subjects and methods: A total of 10 patients were received 20 dental implants. One quadrant in each patient was randomly assigned to control group while other to test group with the help of coin flip. Control group with 10 flapped implants and test group with 10 flapless implants. Follow-up examinations were carried out after 1 week, 1, and 3 months. All treatments were performed under local anesthesia. Peri-implant sulcular fluid samples were collected as well as clinical parameters recorded at the follow up periods. Results: Peri-implant sulcus depth was significantly greater in flapped implants at both 4 and 12 postsurgical weeks (P < 0.005). Matrix metalloproteinase-8 values were higher to a statistically significant level in the control group at 1 (P = 0.003) and 4 weeks (P = 0.007) after placement. Conclusions: Matrix metalloproteinase 8 levels of peri implant crevicular fluid as well as pocket depth were decreased in flapless implants than conventional flap implant surgery.

The Effect of Different Dental Implant Surface Characteristics on Bone Immunologic Biomarkers and Microbiologic Parameters: A Randomized Clinical Study.

This study assessed the levels of tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2), receptor activator of nuclear factor kappa B (RANK), RANK ligand (RANKL), osteoprotegerin (OPG), and levels of Fusobacterium nucleatum, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Prevotella intermedia, and Streptococcus oralis in areas where airborne particle-abraded, large-grit, acid-etched (SLA), fluorine-modified, and anodized implant surfaces are used. A total of 71 implants from 37 patients were assessed, grouped according to the surface characteristics of the implants: SLA surface (Group 1), fluorine-modified surface (Group 2), and anodized surface (Group 3). The following clinical indices were measured: Gingival Index (GI), probing depth (PD), bleeding on probing (BOP), clinical attachment level (CAL), and keratinized tissue width (KTW). Peri-implant sulcus fluid and subgingival plaque samples were also collected. Commercial enzyme-linked immunosorbent assay (ELISA) kits were purchased for measuring TNF-α, PGE2, RANKL, RANK, and OPG. Real-time quantitative polymerase chain reaction (PCR) was used to detect P intermedia, T forsythia, T denticola, F nucleatum, P gingivalis, and S oralis levels in the subgingival biofilms. The groups showed no statistically significant differences in GI, PD, BOP, CAL, KTW, or peri-implant status. The total amounts of PGE2, TNF-α, RANKL, RANK, and OPG and the RANKL/OPG ratio were not significantly different between groups. F nucleatum, T forsythia, P intermedia, P gingivalis, and T denticola were significantly higher in Group 3 implants. DNA concentrations of S oralis were higher in Group 2. Within the limitations of this study, SLA and fluorine-modified implant surfaces may be more clinically successful than anodized-surface implants.

Evaluation of different materials used for sealing of implant abutment access channel and the peri-implant sulcus microbiota: A 6-month, randomized controlled trial.

Peri-implantitis has been attributed to a myriad of factors, including microleakage at the abutment-implant interface. Implant abutment access channel sealing materials (IACSM) are readily used in implant dentistry, with little evidence on their effect on microleakage. This study aims to evaluate the effect of IACSM on the microbial composition in the implant access channel and the peri-implant sulcus. A total of n=8 patients (64 implants) were included in this single-blinded, randomized controlled trial, whereas four different materials (cotton, polytetrafluoroethylene [PTFE], synthetic foam, or polyvinyl siloxane [PVS]) were randomly placed as an IACSM. Following 6months, microbial analysis was completed on the IACSM and samples from the peri-implant sulci via PCR and high-throughput sequencing. Bacterial samples on the IACSM and in the peri-implant sulci were classified according to Socransky's microbial complexes. There was a preponderance of early colonizing bacteria within the IACSM, while the peri-implant sulci were dominated by Orange complex bacteria. The proportion of Red and Orange complex members on the IACSM was significantly less than in the peri-implant sulci. The proportion of Green, Yellow, and Blue complex members found on the IACSM was significantly greater than in the peri-implant sulci. Atopobium, a diverse species not included in the microbial complexes, was frequently detected in the peri-implant sulcus samples. No detectable effects of IACSM on the microbial community in the peri-implant sulcus or on the IACSM were identified. Variation of bacterial species was most dependent on the individual patient. No significant differences were found in theperiodontal parameters between the different treatment groups.

Influence of collar height of definitive restoration and type of luting cement on the amount of residual cement in implant restorations: A clinical study

Statement of problemResidual cement in the peri-implant sulcus may cause peri-implant mucositis, which can lead to peri-implantitis. Clinical studies comparing the role of the collar height of the definitive restoration and the type of cement used for luting the prosthesis in the amount of residual cement are lacking. PurposeThe purpose of this clinical study was to determine the volume of residual cement left undetected in the peri-implant sulcus by an implant prosthesis with 3 different collar heights and 3 luting cements. Material and methodsParticipants with single implants in the premolar region were divided into 3 groups of 10 according to the distance from the peri-implant soft tissue crest to the implant platform: group low collar (sulcus depth <2 mm), group medium collar (2-4 mm), and group high collar (>4 mm). A metal-ceramic crown with an occlusal opening was fabricated on a straight titanium abutment, which facilitated removal of the crown along with the abutment after cementation. The implant luting cements used were composite resin cement (RelyX U200), Type I glass ionomer cement (GC Gold Label 1), and zinc oxide noneugenol interim luting cement (RelyX Temp NE). The modified crown was cemented with 1 cement each during the impression, bisque evaluation, and definitive crown cementation appointments. The crown was retrieved, and the residual cement collected during each appointment. The measurements obtained were statistically analyzed with general linear model analysis followed by post hoc testing using the Bonferroni test (α=.05). ResultsMean volume of the residual excess cement (mm3) formed in group low collar was 0.33 ±0.17, 0.26 ±0.17, and 0.08 ±0.08 for subgroups Resin, GIC, and ZNE, respectively. In group medium collar, it was 1.18 ±0.31, 1.08 ±0.3, and 0.61 ±0.32; and in group high collar, it was 2.33 ±0.31, 2.1 ±0.74, and 1.31 ±0.56 for the same subgroup, respectively. There was a statistically significant difference in the formation of REC between the collar height groups (P<.001). Among the luting cements, zinc oxide noneugenol cement produced significantly lower residual cement compared with the other 2 cements, and there was no statistically significant difference between the glass ionomer and resin cements (P>.05). ConclusionsThe collar height of the definitive restoration and the type of luting cement play significant roles in the formation of residual cement in fixed implant-supported restorations.

Patient-specific establishment of bacterial composition within the peri-implant microbiota during the earliest weeks after implant uncovering.

Dysbiosis, a loss of balance in the microbiota, is a potential factor of peri-implantitis. However, compositional change of the peri-implant microbiota soon after implant uncovering is still unknown. In this study, bacterial composition in the peri-implant sulcus was examined to understand the establishment of bacterial composition within the peri-implant microbiota during the earliest weeks after implant uncovering. Microbiota samples were collected at weeks 1, 2, 4, and 6 after stage-two surgery. Bacterial DNA was isolated from the samples, and a 16S rRNA gene library was constructed. Sequence reads were obtained using a high-throughput sequencing platform and were taxonomically assigned at the phylum and genus levels. Alpha diversity indices, which did not include taxonomic information, were at similar levels throughout the four time points. At 1 and 2weeks, the bacterial composition was similar among patients with the predominance of Firmicutes and Proteobacteria. However, the composition was diverse at 4 and 6weeks and significantly dissimilar to the composition at 1week. At 1week, the peri-implant microbiota was already formed with alpha diversity as high as that at the later time points. However, the bacterial composition was not highly dissimilar among patients at 1week. The composition changed over the passage of several weeks and was specific for each patient.