Georgios A. Kotsakis

Increased Levels of Dissolved Titanium Are Associated With Peri-Implantitis - A Cross-Sectional Study.

BACKGROUND Peri-implantitis represents a disruption of the biocompatible interface between the titanium dioxide layer of the implant surface and the peri-implant tissues. Increasing preclinical data suggest that peri-implantitis microbiota not only triggers an inflammatory immune response but also causes electrochemical alterations of the titanium surfaces, i.e., corrosion, that aggravate this inflammatory response. Thus, it was hypothesized that there is an association between dissolution of titanium from dental implants, which suggests corrosion, and peri-implantitis in humans. The objective of this study is to compare levels of dissolved titanium in submucosal plaque collected from healthy implants and implants with peri-implantitis. METHODS Submucosal plaque from 20 implants with peri-implantitis and 20 healthy implants was collected with sterile curets from 30 participants. Levels of titanium were quantified using inductively coupled plasma mass spectrometry and normalized for mass of bacterial DNA per sample to exclude confounding by varying amounts of plaque per site. Statistical analysis was performed using generalized estimated equations to adjust for clustering of implants per participant. RESULTS Implants with peri-implantitis harbored significantly higher mean levels of titanium (0.85 ± 2.47) versus healthy implants (0.07 ± 0.19) after adjusting for amount of plaque collected per site (P = 0.033). CONCLUSIONS Greater levels of dissolved titanium were detected in submucosal plaque around implants with peri-implantitis compared with healthy implants, indicating an association between titanium dissolution and peri-implantitis. Factors triggering titanium dissolution, as well as the role of titanium corrosion in the peri-implant inflammatory process, warrant further investigation.

Antimicrobial Agents Used in the Treatment of Peri-Implantitis Alter the Physicochemistry and Cytocompatibility of Titanium Surfaces

BACKGROUND Chemotherapeutic agents (ChAs) are considered an integral part of current treatment protocols for the decontamination of titanium implants with peri-implantitis, based on their antimicrobial effect. Despite the proven antimicrobial effect of ChAs on titanium-bound biofilms, previous studies have elucidated an unexpected disassociation between bacterial reduction and biologically acceptable treatment outcomes. In this study, the authors hypothesize that ChAs residues alter titanium physicochemistry and thus compromise cellular response to decontaminated surfaces. METHODS Grit-blasted acid-etched titanium disks were contaminated with multispecies microcosm biofilms grown from in vivo peri-implant plaque samples. To simulate implant decontamination, the contaminated disks were burnished with 0.12% chlorhexidine, 20% citric acid, 24% EDTA/1.5% NaOCl, or sterile saline and assessed surface physicochemical properties. Sterile untreated surfaces were the controls. The biologic effects of decontamination were assessed via cell proliferation and differentiation assays. RESULTS Bacterial counts after decontamination confirmed that the ChAs were antimicrobial. X-ray photoelectron spectroscopy invariably detected elemental contaminants associated with each ChA molecule or salt that significantly altered wettability compared with controls. Notably, all surfaces with ChA residues showed some cytotoxic effect compared with controls (P <0.05). Increased cell counts were consistently found in the saline-treated group compared with chlorhexidine (P = 0.03). Interestingly, no association was found between antimicrobial effect and cell counts (P >0.05). CONCLUSIONS ChA-specific residues left on the titanium surfaces altered titanium physical properties and adversely affected the osteoblastic response irrespective of their observed antimicrobial effect. Chlorhexidine may compromise the biocompatibility of titanium surfaces, and its use is not recommended to detoxify implants. Sterile saline, citric acid, and NaOCl-EDTA may be proposed for use in the treatment of peri-implantitis. Contrary to previous studies that recommended the selection of ChAs for the decontamination of titanium implants according to their antimicrobial effects, the present study demonstrated that the restoration of the biocompatibility of contaminated titanium surfaces is also contingent on the preservation of titanium material properties.

Dietary inflammatory potential is linked to cardiovascular disease risk burden in the US adult population

BACKGROUND Dietary guidelines are a key tool in the public health quiver. Single nutrients have been linked to cardiovascular diseases, but existing metrics do not capture the overall effect of diet on inflammatory diseases. The aim of this study was to examine the association between dietary inflammatory potential and cardiovascular diseases risk factors (CVD-RFs) in a nationally-representative sample of non-institutionalized US adults using data from the continuous National Health and Nutrition Examination Survey (NHANES) (2007-2012). METHODS AND RESULTS A sample of 7880 non-institutionalized US adults aged ≥20years provided data on dietary habits and CVD-RFs (obesity; diabetes mellitus; hypertension; hypercholesterolemia). The total number of CVD-RFs was summed for each individual to create a CVD-RF morbidity index (range 0-4) as the outcome variable, used both as ordinal and dichotomous (no CVD-RFs versus at least one CVD-RF) variables. The association between the Dietary Inflammatory Index (DII) and at least one CVD-RF was dose-dependent, with participants in the 3rd and 4th quartile of DII (i.e., more pro-inflammatory dietary habits) being 1.37 (95%CI=1.11-1.68) and 1.50 (95%CI=1.19-1.90) times more likely, respectively, to have at least one CVD-RF, as compared to participants in the 1st quartile of DII scores. Similar results were obtained for the ordinal logistic regression using the CVD-RF morbidity index as the outcome. CONCLUSIONS Among US adults aged ≥20years, pro-inflammatory dietary patterns, as assessed by the DII, were associated with increased odds for CVD-RFs. Dietary guidelines aimed at lowering the DII may reduce the CVD-RF burden in US adults.

Investigation of the Association Between Cement Retention and Prevalent Peri-Implant Diseases: A Cross-Sectional Study

BACKGROUND The aim of this study is to examine the association between retention type (cement-retained versus screw-retained restorations) and prevalence of peri-implant diseases in a German university-treated population. METHODS Data were analyzed from individuals that underwent clinical and radiographic peri-implant examinations as part of a university-based cross-sectional study from September 2011 to October 2012. RESULTS Data from 139 individuals (mean age: 57.59 years) having 394 implants were analyzed: 192 implants supporting single crowns and 202 fixed partial dentures. Overall, 11.9% of the participants had peri-implantitis, whereas 68.9% had peri-implant mucositis. Crude odds ratios (95% confidence intervals) for peri-implantitis and peri-implant mucositis for cement- versus screw-retained restorations were 1.43 (0.45, 4.60) and 0.89 (0.53, 1.48), respectively. Results remained non-significant in multivariable models adjusting for type of restoration and smoking (all P values >0.50). There was also no effect of splinting restorations on disease prevalence in adjusted analyses (P values >0.32). CONCLUSIONS In this university-treated sample, there is no association between the type of prosthesis retention and peri-implant diseases. Current findings show that, when appropriate selection and removal of cement is performed, cement retention is not a risk indicator for peri-implant diseases.

Binary Decision Trees for Preoperative Periapical Cyst Screening Using Cone-beam Computed Tomography

Introduction: Cone‐beam computed tomographic (CBCT) analysis allows for 3‐dimensional assessment of periradicular lesions and may facilitate preoperative periapical cyst screening. The purpose of this study was to develop and assess the predictive validity of a cyst screening method based on CBCT volumetric analysis alone or combined with designated radiologic criteria. Methods: Three independent examiners evaluated 118 presurgical CBCT scans from cases that underwent apicoectomies and had an accompanying gold standard histopathological diagnosis of either a cyst or granuloma. Lesion volume, density, and specific radiologic characteristics were assessed using specialized software. Logistic regression models with histopathological diagnosis as the dependent variable were constructed for cyst prediction, and receiver operating characteristic curves were used to assess the predictive validity of the models. A conditional inference binary decision tree based on a recursive partitioning algorithm was constructed to facilitate preoperative screening. Results: Interobserver agreement was excellent for volume and density, but it varied from poor to good for the radiologic criteria. Volume and root displacement were strong predictors for cyst screening in all analyses. The binary decision tree classifier determined that if the volume of the lesion was >247 mm3, there was 80% probability of a cyst. If volume was <247 mm3 and root displacement was present, cyst probability was 60% (78% accuracy). Conclusions: The good accuracy and high specificity of the decision tree classifier renders it a useful preoperative cyst screening tool that can aid in clinical decision making but not a substitute for definitive histopathological diagnosis after biopsy. Confirmatory studies are required to validate the present findings. HighlightsLesion volume was the strongest predictor for cyst screening.Volumetric and densimetric analyses were more reliable measures than radiologic assessment.A classification tree with 2 input variables gave the best prediction for cyst screening.

Osteostimulative calcium phosphosilicate biomaterials partially restore the cytocompatibility of decontaminated titanium surfaces in a peri-implantitis model: OSTEOSTIMULATIVE BIOMATERIALS RESTORE TITANIUM CYTOCOMPATIBILITY

Bacterial peri-implant biofilms, and the chemotherapeutics for their removal alter titanium surface cytocompatibility. In this study we aimed to assess the adjunctive use of an osteostimulative biomaterial utilizing a peri-implantitis model under the hypothesis that it will increase cell migration towards treated titanium surfaces. Acid-etched titanium surfaces were inoculated with a multi-species biofilm model and treated with 1.5% NaOCl in a previously characterized in vitro peri-implantitis model. Cell migration of MG63 cells towards the treated titanium surface (CTRL) was significantly reduced following inoculation with biofilm and chemotherapeutic treatment as compared to sterile controls. Addition of a tricalcium phosphate biomaterial (TCP) as a control for Ca+2 had a small non-significant effect, while BG significantly increased MG63 chemotaxis to titanium to levels comparable to sterile (STE). Similarly, cell viability at 5 days was increased in BG and TCP as compared to CTRL. SEM imaging confirmed the improved cytocompatibility of BG and TCP surfaces as compared to CTRL. Osteostimulative BG exhibited a strong chemotactic effect to osteoblasts, which was stronger than what was expected due to the chemotactic effect of Ca+2 alone (TCP). In addition, substantially increased cell attachment and viability was found on treated implant surfaces as compared to CTRL.

Titanium as a modifier of the peri-implant microbiome structure

BACKGROUND Recent data support the implication of accelerated titanium dissolution products in peri-implantitis. It is unknown whether these dissolution products have an effect on the peri-implant microbiome, the target of existing peri-implantitis therapies. PURPOSE This study assessed the relationship between the peri-implant microbiome, dissolved titanium levels, and peri-implantitis. MATERIALS AND METHODS Clinical, microbiome, and titanium data were collected from a periodontal population having implants in function for 10 years. Clinical examinations were performed, and submucosal plaque samples were collected from the deepest site per implant. An aliquot of the sample was used for 16S rRNA gene sequencing, with the remainder analyzed for titanium quantity using mass spectrometry. Sequences were clustered into taxonomic units at 97% minimum sequence similarity using the QIIME pipeline approach. RESULTS Fifteen implants were assessed. According to established case definitions, six had a diagnosis of peri-implantitis; nine were healthy. The genera Streptococcus, Prevotella and Haemophilus characterized peri-implant health. Peri-implantitis was associated with a marked increase in Veillonella. Quantities of dissolved titanium were identified in 40% of sites. Titanium presence was associated with peri-implant disease status (P = .02) and correlated to the first principal component of the microbiome (rho = 0.552) and its alpha-diversity (rho = -0.496). Canonical correlation analyses found that titanium levels, but not health or disease status of the implant, were significantly associated with the microbiota composition (P = .045). CONCLUSIONS These findings suggest an association between titanium dissolution products and peri-implantitis and support a role for these products in modifying the peri-implant microbiome structure and diversity.

Enhancing root eminence and papilla contour using single, contoured, subepithelial connective tissue autografts for recession coverage

Current techniques using autogenous soft tissue in periodontal plastic surgery have limitations in the number of teeth that can be treated and may result in suboptimal esthetic results. The innovative use of single, contoured grafts reported in this article overcomes the drawbacks associated with these techniques by more efficient use of available donor tissue. Autogenous tissue is used to graft each individual tooth, leaving the interdental areas uncovered. Multiple teeth-in some cases an entire arch-can be treated in one session, providing consistent and predictable reestablishment of the normal scalloped gingival architecture and convex root eminence.