Academy Report: Peri-Implant Mucositis and Peri-Implantitis: A Current Understanding of Their Diagnoses and Clinical Implications

Time resolved 3D live-cell imaging on implants

It is estimated that two million new dental implants are inserted worldwide each year. Innovative implant materials are developed in order to minimize the risk of peri-implant inflammations. The broad range of material testing is conducted using standard 2D, terminal, and invasive methods. The methods that have been applied are not sufficient to monitor the whole implant surface and temporal progress. Therefore, we built a 3D peri-implant model using a cylindrical implant colonized by human gingival fibroblasts. In order to monitor the cell response over time, a non-toxic LIVE/DEAD staining was established and applied to the new 3D model. Our LIVE/DEAD staining method in combination with the time resolved 3D visualization using Scanning Laser Optical Tomography (SLOT), allowed us to monitor the cell death path along the implant in the 3D peri-implant model. The differentiation of living and dead gingival fibroblasts in response to toxicity was effectively supported by the LIVE/DEAD staining. Furthermore, it was possible to visualize the whole cell-colonized implant in 3D and up to 63 hours. This new methodology offers the opportunity to record the long-term cell response on external stress factors, along the dental implant and thus to evaluate the performance of novel materials/surfaces.

Evaluation of Clinical Parameters in Implant Maintenance Phase for Prevention of Peri-implantitis

Aims and Objectives

Peri-implant mucositis and peri-implantitis are one of the common biological complications affecting implant success. The present study aimed to evaluate various clinical parameters during implant maintenance phase.

Materials and Methods

The study included patients undergoing implant maintenance phase for 1-year follow-up. The study consists of a total of forty individuals with age ranging from 35 to 65 years. They were further categorized into two subgroups on the basis of their history, i.e., Group 1: patients with no history of periodontitis before implant placement and Group 2: patients with a history of periodontitis before implant placement. Among the selected patients, a total of 98 implants were studied. All were individually evaluated for clinical parameters such as gingival index, pocket probing depth (PPD), and bleeding on probing (BOP). All the data obtained were tabulated and analyzed using statistical software SPSS version 18.0 for Windows (SPSS Inc., Chicago, USA). Quantitative analysis was done using t-test and Mann-Whitney U-test.

Results

The mean age of the patients in Group 1 and Group 2 was 58.6 and 62.8 years, respectively, with not much gender difference. The mean plaque index for Group 1 was 0.17 ± 0.20, while for Group 2, it was 0.24 ± 0.14. The mean PPD and mean BOP for Group 1 came to be 2.60 ± 0.42 and 0.42 ± 0.15, respectively, whereas for Group 2, it was 4.08 ± 0.30 and 0.39 ± 0.48, respectively. Only PPD was found to be statistically significantly different between both the groups. Group 1 showed 2.0% peri-implantitis, whereas Group 2 showed 28% peri-implantitis.

Conclusion

Due to increased prevalence of peri-implantitis cases with the increase in usage of implants, it becomes imperative to look up to the etiological factors and contributing factors so that the incidence of these can be minimized.

Survival rates of hybrid rough surface implants and their alveolar bone level alterations

BACKGROUND

The design of hybrid surface implants takes advantage of characteristics of two different textures to improve clinical outcomes. To date, there are limited numbers of studies reporting the clinical results of hybrid surface implants. This study aimed to assess hybrid surface implants with two different rough textures in regard to survival, marginal bone level change, and biological complications.

METHODS

Retrospective review of dental records was conducted for 161 patients who had 460 hybrid surface implants to analyze survival rate. These implants had the dual sandblasted and anode oxidized surface. Sixty patients with 192 implants who had consecutive radiographs taken at specific time points and complete clinical examinations were included in the comprehensive analysis. The associations between patient- and implant-related characteristics, and clinical results were analyzed by log-rank test, Cox regression, and linear regression analysis.

RESULTS

Cumulative survival at 12, 36, and 60 months after placement was 97.4%, 96.4%, and 95.8%, respectively. The average marginal bone level change from baseline to the last visit was 0.31 ± 0.68 mm and 0.34 ± 0.77 mm at the mesial and distal sites, respectively. Prevalence of peri-implantitis was 0.5% at the implant level and 1.7% at the patient level. Implant site was associated with implant failure (P = 0.03). Smoking habit, history of periodontitis, and implant site were significantly associated with marginal bone level change (P = 0.001, < 0.001, 0.01, respectively).

CONCLUSIONS

Hybrid rough surface implants had high survival rate, stable bone level, and low prevalence of biological complications. This surface design demonstrated promising clinical outcomes. More studies are needed to further support the clinical advantages of hybrid surface implants.

Ultrasonography for noninvasive and real-time evaluation of peri-implant tissue dimensions

AIM

Existing methods for evaluating marginal bone loss and tissue biotype around dental implants present with many limitations. The aim of this study was to examine the accuracy of high-resolution, 3-dimensional ultrasound to measure peri-implant tissue dimensions.

MATERIAL AND METHODS

A 25-MHz ultrasound probe prototype was used to scan peri-implant tissues of 17 implants from seven fresh human cadavers. Four ultrasonic measurements were made as follows: the marginal bone level/thickness, and mucosal level/thickness. The readings were statistically compared to cone beam computed tomography (CBCT) and/or open bone measurements.

RESULTS

The correlations (r) between the ultrasound and direct/CBCT readings of the four parameters ranged from 0.85 to 0.98 (p < 0.0001). The mean absolute difference in the four parameters between ultrasound-direct and ultrasound-CBCT ranged from 0.033 to 0.24 mm.

CONCLUSION

Encouraging evidence is shown that ultrasound can accurately measure peri-implant tissue dimensions. Following clinical trial validations, ultrasound offers potential as a valuable tool to evaluate long-term peri-implant tissue stability without concerns of ionizing radiation and image artefacts around implants.

Peptide coatings enhance keratinocyte attachment towards improving the peri-implant mucosal seal

There is a critical need for preventing peri-implantitis as its prevalence has increased and dental implants lack features to prevent it. Research strategies to prevent peri-implantitis have focused on modifying dental implants to incorporate different antimicrobial agents. An alternative strategy consists of barring the expansion of the biofilm subgingivally by forming a long-lasting permucosal seal between the soft tissue and the implant surface. Here, we innovatively biofunctionalized titanium with bioinspired peptide coatings to strengthen biological interactions between epithelial cells and the titanium surface. We selected laminin 332- and ameloblastin-derived peptides (Lam, Ambn). Laminin 332 participates in the formation of hemidesmosomes by keratinocytes and promotes epithelial attachment around teeth; and ameloblastin, an enamel derived protein, is involved in tissue regeneration events following disruption of the periodontium. Lam, Ambn or combinations of both peptides were covalently immobilized on titanium discs. Successful immobilization of the peptides was confirmed by contact angle goniometry, X-ray photoelectron spectroscopy and fluorescent labelling of the peptides. Additionally, we confirmed the mechanical and thermochemical stability of the peptides on Ti substrates. Proliferation and hemidesmosome formation of human keratinocytes (TERT-2/OKF-6) were assessed by immunofluorescence labelling. The peptide-coated surfaces increased cell proliferation for up to 48 h in culture compared to control surfaces. Most importantly, formation of hemidesmosomes by keratinocytes was significantly increased on surfaces coated with Ambn + Lam peptides compared to control (p < 0.01) and monopeptide coatings (p < 0.005). Together, these results support the Ambn + Lam multipeptide coating as a promising candidate for inducing a permucosal seal around dental implants.

Early intervention of peri-implantitis and periodontitis using a mouse model

BACKGROUND

Peri-implantitis is an inflammatory response to bacterial biofilm resulting in bone loss and can ultimately lead to implant failure. Because of the lack of predictable treatments available, a thorough understanding of peri-implantitis's pathogenesis is essential. The objective of this study is to evaluate and compare the response of acute induced peri-implantitis and periodontitis lesions after insult removal.

METHODS

Implants were placed in one-month-old C57BL/6J male mice eight weeks post extraction of their left maxillary molars. Once osseointegrated, ligatures were placed around the implants and contralateral second molars of the experimental groups. Controls did not receive ligatures. After one week, half of the ligatures were removed, creating the ligature-retained and ligature-removed groups. Mice were sacrificed at two time points, 5 and 14 days, from ligature removal. The specimens were analyzed via micro-computed tomography and histology.

RESULTS

By 5 and 14 days after ligature removal, the periodontitis group experienced significant bone gain, whereas the peri-implantitis group did not. Histologically, all implant groups exhibited higher levels of cellular infiltrate than any of the tooth groups. Osteoclast numbers increased in peri-implantitis and periodontitis ligature-retained groups and decreased following insult removal. Collagen was overall more disorganized in peri-implantitis than periodontitis for all groups. Peri-implantitis experimental groups revealed greater matrix metalloproteinase-8 and NF-kB levels than periodontitis.

CONCLUSIONS

Implants respond slower and less favorably to insult removal than teeth. Future research is needed to characterize detailed peri-implantitis disease pathophysiology.

Initial and long-term crestal bone responses to modern dental implants

Successful osseointegration is the result of a controlled foreign body reaction to dental implants. Osseointegrated implants have demonstrated excellent long-term survivability, although they may be subject to limited marginal bone loss. Marginal bone loss during the first few years after implant placement seldom represents disease, but is instead the result of an adaptive bone response to surgical trauma and implant loading. It is not uncommon for implants with early marginal bone loss to enter a long-lasting state of bone stability. Extensive bone resorption after the first year is generally due to an exacerbation of adverse body reactions caused by non-optimal implant components, adverse surgery or prosthodontics and/or compromised patient factors. Disease in the form of peri-implantitis is a late complication that affects some implants with suppuration and rapid loss of crestal bone, and is probably caused by bacterial pathogens and immunological reactions. Unfortunately, the literature is not consistent with respect to the type or magnitude of clinical implant problems, including how they are defined and diagnosed. If the peri-implantitis diagnosis is confined to cases with infection, suppuration and significant bone loss, the frequency of the disease is relatively low, which is in sharp contrast to the frequencies reported with unrealistic definitions of peri-implantitis. We suggest that when modern implants are placed by properly trained individuals, only 1-2% of implants show true peri-implantitis during follow-up periods of 10 years or more. Peri-implantitis must be separated from the initial and self-limiting marginal bone loss.

Clinical and Radiographic Peri-Implant Parameters and Whole Salivary Interleukin-1β and Interleukin-6 Levels among Type-2 Diabetic and Nondiabetic Patients with and without Peri-Implantitis

OBJECTIVE

The aim was to assess the peri-implant clinical and radiographic parameters and whole salivary levels of interleukin (IL)-1β and IL-6 among type 2 diabetic and nondiabetic patients with and without peri-implantitis.

MATERIAL AND METHODS

Ninety-one implants were placed in patients without type 2 diabetes mellitus (39 patients with and 52 patients without peri-implantitis; group 1). Eighty implants were placed in patients with diabetes (35 patients with and 45 patients without peri-implantitis; group 2). Peri-implant plaque index, bleeding on probing, probing depth, and marginal bone loss were measured. Unstimulated whole saliva samples were collected and IL-1β and IL-6 levels were measured using standard techniques. p < 0.05 was considered statistically significant.

RESULTS

In group 1, plaque index (p < 0.001), bleeding on probing (p < 0.001), probing depth (p < 0.001), and whole salivary IL-1β (p < 0.001) and IL-6 (p < 0.001) levels were significantly higher in patients with peri-implantitis than in those without peri-implantitis. Plaque index, bleeding on probing, probing depth, and marginal bone loss were comparable among all of the patients in group 2. Among patients with peri-implantitis, plaque index (p < 0.001), bleeding on probing (p < 0.001), probing depth (p < 0.001), marginal bone loss (p < 0.001), and whole salivary IL-1β (p < 0.001) and IL-6 (p < 0.001) levels were significantly higher in those with diabetes than in those without diabetes.

CONCLUSION

Among individuals without diabetes, peri-implant plaque index, bleeding on probing, probing depth, marginal bone loss, and whole salivary IL-1 β and IL-6 levels were higher among patients with peri-implantitis compared to patients without peri-implantitis. Among patients with diabetes, the severity of the measured parameters appears to be influenced by the glycemic status rather than by peri-implantitis.

Ligature-induced peri-implantitis and periodontitis in mice

AIM

Peri-implantitis (PI), inflammation around dental implants, shares characteristics with periodontitis (PD). However, PI is more difficult to control and treat, and detailed pathophysiology is unclear. We aimed to compare PI and PD progression utilizing a murine model.

MATERIALS AND METHODS

Four-week-old male C57BL/6J mice had their left maxillary molars extracted. Implants were placed in healed extraction sockets and osseointegrated. Ligatures were tied around the implants and second molars. Controls did not receive ligatures. Mice were sacrificed 1 week, 1 and 3 months (n ≥ 5/group/time point) post-ligature placement. Bone loss analysis was performed. Histology was performed for: haematoxylin and eosin (H&E), tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinase-8 (MMP-8), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), toluidine blue and calcein.

RESULTS

PI showed statistically greater bone loss compared to PD at 1 and 3 months. At 3 months, 20% of implants in PI exfoliated; no natural teeth exfoliated in PD. H&E revealed that alveolar bone surrounding implants in PI appeared less dense compared to PD. PI presented with increased osteoclasts, MMP-8 and NF-κB, compared to PD.

CONCLUSION

PI exhibited greater tissue and bone destruction compared to PD. Future studies will characterize the pathophysiological differences between the two conditions.

Is Metal Particle Release Associated with Peri-implant Bone Destruction? An Emerging Concept

Peri-implant diseases affecting the surrounding structures of endosseous dental implants include peri-implant mucositis and peri-implantitis. The prevalence of peri-implantitis ranges between 15% and 20% after 10 y, highlighting the major challenge in clinical practice in the rehabilitation of dental implant patients. The widespread nature of peri-implant bone loss poses difficulties in the management of biological complications affecting the long-term success of osseointegrated implant reconstructions. Metal and titanium particles have been detected in peri-implant supporting tissues. However, it remains unclear what mechanisms could be responsible for the elicitation of particle and ion release and whether these released implant-associated materials have a local and/or systemic impact on the peri-implant soft and hard tissues. Metal particle release as a potential etiologic factor has been intensively studied in the field of orthopedics and is known to provoke aseptic loosening around arthroplasties and is associated with implant failures. In dental medicine, emerging information about metal/titanium particle release suggests that the potential impact of biomaterials at the abutment or bone interfaces may have an influence on the pathogenesis of peri-implant bone loss. This mini-review highlights current evidence of metal particle release around dental implants and future areas for research.

Implant failure and history of failed endodontic treatment: A retrospective case-control study

Background

Residual bacterial biofilm and/or bacteria in planktonic form may be survived in the bone following an extraction of an infected tooth that was endodontically treated unsuccessfully Failed endodontic treatment may be associated with failure of implants to osseointegrate in the same sites. Therefore, the aim of this retrospective case-control study is to examine the risk of implant failure in previous failed endodontic sites.

Material and Methods

This retrospective case-control study is based on 94 dental records of implants placed at the University of Minnesota School of Dentistry. Dental records of patients who received an implant in sites with previously failed endodontic therapy in the dental school were identified from the electronic database, while control subjects were obtained from the same pool of patients with the requirement to have received an implant in a site that was not endodontically treated.

Results

The mean age of the population was 62.89±14.17 years with 57.4% of the sample being females and 42.6% of them being males. In regards to the socio-economic status and dental insurance, 84.0% of this population was classified as low socio-economic status and 68.1% had dental insurance. Tobacco use was self-reported by 9.6% and hypercholesterolemia was the most prevalent systemic medical condition. Dental implant failure was identified in two of the included records (2.1%), both of which were placed in sites with a history of failed endodontic treatment.

Conclusions

Within the limitations of this retrospective case-control study, further investigation with a larger population group into implant failure of sites that previously had unsuccessful endodontic treatment would be warranted. Implant failure may be associated with a history of failed endodontic treatment.

Key words:Implantology, endodontics, osseointegration, treatment outcome, case-control study.

Susceptibility of different mouse strains to peri-implantitis

BACKGROUND AND OBJECTIVE

Peri-implantitis (PI) is an inflammatory condition that affects the tissues surrounding dental implants. Although the pathogenesis of PI is not fully understood, evidence suggests that the etiology is multifactorial and may include a genetic component. The aim of this study was to investigate the role of genetics in the development of peri-implantitis.

MATERIAL AND METHODS

Four-week-old C57BL/6J, C3H/HeJ and A/J male mice had their left maxillary molars extracted. Implants were placed in the healed extraction sockets. Upon osseointegration, ligatures were placed around the implant head for 1 or 4 weeks to induce PI. Micro-computed tomography scanning was used to measure volumetric bone loss. Histological analyses were also performed to evaluate collagen organization and the presence of neutrophils and osteoclasts.

RESULTS

Radiographically, comparing the ligature-treated mice, C57BL/6J displayed the greatest amount of bone loss, followed by C3H/HeJ and A/J mice at 1 and 4 weeks. Histologically, at 1 week, C57BL/6J mice presented with the highest numbers of neutrophils and osteoclasts. At 4 weeks, C57BL/6J mice presented with the most active bone remodeling compared with the other two strains.

CONCLUSION

There were significant differences in the severity of peri-implantitis among the different mouse strains, suggesting that the genetic framework can affect implant survival and success. Future work is needed to dissect the genetic contribution to the development of peri-implantitis.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Parameters to Define Peri-Implantitis: A Review and a Proposed Multi-Domain Scale

Peri-implant diseases have received much attention since dental implants are generally used in contemporary dentistry. Several contributing factors associated with the development of peri-implant diseases have also been investigated. The prevalence of peri-implantitis has been reported but with great heterogeneity because of a lack of a universally accepted classification system that could define the extent and severity of peri-implantitis. Several parameters-including radiographic bone loss, probing depth, bleeding on probing, and suppuration-have been introduced in these reports to assist with clinical diagnosis. This article provides an objective evaluation of these parameters based on currently available evidence, offers further recommendations, and proposes a multidomain scale for diagnosis of peri-implantitis. Future investigations and modifications may be needed to develop a comprehensive, evidence-based classification system that addresses the multifactorial etiology of peri-implant diseases.

Antimicrobial effect of titanium dioxide after ultraviolet irradiation against periodontal pathogen

We focused on the antimicrobial effects of titanium dioxide (TiO2) after stopping ultraviolet (UV) irradiation as an adjunctive treatment for peri-implantitis in this study. The aim was to determine the continuous photocatalytic effects of TiO2 after UV irradiation and its antimicrobial activity against periodontal pathogen. The continuous photocatalytic effects of TiO2 after UV irradiation were determined by electron spin resonance (ESR) spectroscopy using TiO2 particles of various sizes with various UV irradiation times. In addition, antimicrobial activity against Porphyromonas gingivalis was investigated by quantitation of colony-forming units (CFUs). The results showed that the ESR signal ratio for the UV-irradiated TiO2 was significantly higher than that of the non-irradiated TiO2. UV-irradiated TiO2 significantly reduced the number of P. gingivalis when compared with non-irradiated controls. These results suggest that TiO2 has a continuous photocatalytic effect even after stopping UV irradiation and that it showed antimicrobial activity against periodontal pathogen.

Immediate Loading of Tapered Implants Placed in Postextraction Sockets and Healed Sites

OBJECTIVE

The aim of the present study was to compare the survival, stability, and complications of immediately loaded implants placed in postextraction sockets and healed sites.

METHODS

Over a 2-year period, all patients presenting with partial or complete edentulism of the maxilla and/or mandible (healed site group, at least 4 months of healing after tooth extraction) or in need of replacement of nonrecoverable failing teeth (postextraction group) were considered for inclusion in this study. Tapered implants featuring a nanostructured calcium-incorporated surface were placed and loaded immediately. The prosthetic restorations comprised single crowns, fixed partial dentures, and fixed full arches. Primary outcomes were implant survival, stability, and complications. Implant stability was assessed at placement and at each follow-up evaluation (1 week, 3 months, and 1 year after placement): implants with an insertion torque (IT) <45 N·cm and/or with an implant stability quotient (ISQ) <70 were considered failed for immediate loading. A statistical analysis was performed.

RESULTS

Thirty implants were placed in postextraction sockets of 17 patients, and 32 implants were placed in healed sites of 22 patients. There were no statistically significant differences in ISQ values between the 2 groups, at each assessment. In total, 60 implants (96.8%) had an IT ≥45 and an ISQ ≥70 at placement and at each follow-up control: all these implants were successfully loaded. Only 2 implants (1 in a postextraction socket and 1 in a healed site, 3.2%) could not achieve an IT ≥45 N·cm and/or an ISQ ≥70 at placement or over time: accordingly, these were considered failed for stability, as they could not be subjected to immediate loading. One of these 2 implants, in a healed site of a posterior maxilla, had to be removed, yielding an overall 1-year implant survival rate of 98.4%. No complications were reported. No significant differences were reported between the 2 groups with respect to implant failures and complications.

CONCLUSION

Immediately loaded implants placed in postextraction sockets and healed sites had similar high survival and stability, with no reported complications. Further long-term studies on larger samples of patients are needed to confirm these results.

Immediate Loading of Single Implants in the Anterior Maxilla: A 1-Year Prospective Clinical Study on 34 Patients

Purpose

To present the outcomes of immediately loaded single implants placed in the anterior maxilla.

Methods

Over a 2-year period, all patients referred to a private clinic were considered for enrolment in this study. Inclusion criteria were single-tooth placement in postextraction sockets or healed sites of the anterior maxilla. All implants were immediately loaded and followed for a period of 1 year after the placement of definitive crowns. The outcome measures were implant stability, survival, and success.

Results

34 patients were selected and 43 tapered implants with a knife-edge thread design and a nanostructured, calcium-incorporated surface (Anyridge®, Megagen, Gyeongsang, Korea) were installed. Two implants were not sufficiently stable at placement (ISQ < 60) and were considered failed for immediate loading; 41 implants had an ISQ ≥ 60 at placement and were immediately loaded. One year after the placement of definitive crowns, no implant failures were reported, for a survival rate of 100%. No biological complications were found, but 2 implants had their prosthetic abutments loosened: the implant success rate was 95.2%.

Conclusions

In the present study on the immediate loading of single implants in the anterior maxilla, positive outcomes were reported, with high survival (100%) and success (95.2%) rates (the present study has been registered in the ISRCTN registry, a publicly available trial register recognized by WHO and ICMJE, with number ISRCTN12935478).

Osteoblast growth, after cleaning of biofilm-covered titanium discs with air-polishing and cold plasma

AIM

To investigate the effects of a combined biofilm removal with an optimized air polishing and a cold plasma device on cells in vitro.

MATERIALS AND METHODS

A 7-day-old biofilm was removed from rough titanium discs with an air-polishing device with erythritol powder (AP) or with a cold atmospheric pressure argon plasma (CAP) device or in combination of both (AP + CAP). The removal efficacy was evaluated by subsequent cell seeding of osteoblast-like cells (MG-63). The cell spreading was analysed after 5 days of incubation by scanning electron microscopy. Separately, the surface hydrophilicity was analysed by measuring the water contact angle (WCA) of the disc for each treatment method.

RESULTS

The mechanical plaque removal with AP rendered specimen conducive for cell growth, 85% of the surface was covered with cells. An advantage of the combination of AP + CAP was not detectable compared to AP (cell coverage ranged from 57% up to 75%). After sole CAP treatment, microorganisms re-grew and destroyed all cells. The WCA was reduced by all treatment methods.

CONCLUSION

An AP treatment has the potential to remove biofilm from rough implant surfaces completely. In contrast to our hypothesis, the combination of plasma and AP treatment did not enhance osteoblast spreading.

Prevalences of peri-implantitis and peri-implant mucositis: systematic review and meta-analysis

OBJECTIVES

Due to the inconsistent definitions, reporting methods and study characteristics, prevalences of peri-implant diseases significantly varied in studies. This study aimed to systematically analyze implant-based and subject-based prevalences of peri-implant diseases and assess clinical variables potentially affecting the prevalence.

SOURCES

Electronic search of studies was conducted using MEDLINE (PubMed), EMBASE and Web of Science. Publication screening, data extraction, and quality assessment were performed.

STUDY SELECTION

Clinical studies having an at least average three-year follow-up period were selected. The numbers of subjects and implants in the studies had to be equal to or more than thirty.

DATA

Forty seven studies were selected and prevalences of peri-implant diseases were analyzed. Since heterogeneity existed in each outcome (I²=94.7, 95.7, 95.3, and 99.3 for implant-based and subject-based peri-implantitis and peri-implant mucositis, respectively), the random-effects model based on the DerSimonian and Laird method, which incorporate an estimate of heterogeneity in the weighting, was applied to obtain the pooled prevalence. Weighted mean implant-based and subject-based peri-implantitis prevalences were 9.25% (95% Confidence Interval (CI): [7.57, 10.93]) and 19.83% (CI [15.38, 24.27) respectively. Weighted mean implant-based and subject-based peri-implant mucositis prevalences were 29.48% (CI: [22.65, 36.32]) and 46.83% (CI: [38.30, 55.36]) respectively. Functional time and implant to subject ratio were associated with subject-based peri-implantitis prevalence, but not peri-implant mucositis prevalences.

CONCLUSIONS

Peri-implant diseases were prevalent and prevalence of peri-implantitis increased over time. Prevalences of peri-implantitis and peri-implant mucositis might not be highly associated since the prevalences were influenced by distinct variables. The results should be carefully interpreted because of data heterogeneity.

CLINICAL SIGNIFICANCE

Peri-implant diseases affect a significant number of dental implants and patients. It is important to understand the difficulties in diagnosis of these diseases and risk factors which may be modified to reduce the potential for disease occurrence or progression.

Herpes Simplex 1 and Periopathogen Role in Peri-implantitis

INTRODUCTION

The objectives of this study were to compare the qualitative and quantitative profiles of herpes simplex virus type I (HSV-1) in implant surfaces between participants with peri-implantitis (PI) and Healthy peri-implant tissues and to quantitatively assess the relation between HSV-1 and periopathogens inside the microbiological profile associated with PI.

MATERIALS AND METHODS

A total of 40 patients with PI and 40 with healthy peri-implant tissues (HI) were recruited. Plaque samples from peri-implant sulcus and internal implant connections were analyzed using quantitative real-time polymerase chain reaction to detect and quantify HSV-1 and periodonto-pathogens. Frequencies of detection and levels of microorganisms were compared between PI and HI; the frequencies and levels of periodontopathogens were compared between HSV-1+ and HSV-1- PI to assess qualitative relations between HSV-1 and bacteria. Correlation between HSV-1 and periodontopatho-gens levels was assessed in PI and HI.

RESULTS

A total of 77 dental implants affected by PI, and 113 HIs were included. The HSV-1 prevalence was slightly higher in PI compared with controls (33.3 vs 23.8%; p > 0.05); HSV-1 was detected in external samples more frequently compared with internal samples. The HSV-1-positive patients revealed higher median loads of Prevotella intermedia (Pi) and Campylobacter rectus (Cr) compared with HSV-1-negative patients. In the PI group, a significant positive correlation was evidenced between HSV-1 and Tannerella forsythia, Parvimonas micra (Pm), Fusobacterium nucleatum, and Cr levels, while in the HI, positive correlation between HSV-1 and Aggregatibacter actinomycetemcomitans, Pi, and Pm was established.

CONCLUSION

The HSV-1 prevalence cannot be used to identify PI. The HSV-1 was found in similar levels of PI and HI patients after an average of 6 years of loaded implants. The HSV-1 prevalence cannot be used to identify implants with or without the presence of PI.

CLINICAL SIGNIFICANCE

Although HSV-1 is detected in PI site, HSV-1 may represent an unspecific indicator for the host response to the bacterial challenge observed in PI.

Biomarkers and Bacteria Around Implants and Natural Teeth in the Same Individuals

BACKGROUND

This cross-sectional study assesses cytokine levels in peri-implant crevicular fluid (PICF)/gingival crevicular fluid (GCF) and a selection of subgingival/submucosal plaque bacteria from clinically healthy or diseased sites in the same individuals.

METHODS

Samples from 97 implants/teeth (58 implants [19 healthy, 20 mucositis, 19 peri-implantitis] and 39 natural teeth [19 healthy, 12 gingivitis, eight periodontitis] in 15 systemically healthy patients were investigated by immunoassay and real-time polymerase chain reaction. Samples were obtained first, with probing depth, clinical attachment level, bleeding on probing, plaque index scores, and keratinized tissue width then recorded. Data were analyzed by Wilcoxon, Mann-Whitney U, and permutation tests on dependent, independent, and mixed dependent and independent samples and Spearman correlation.

RESULTS

Interleukin (IL)-1β levels were significantly higher in PICF samples of healthy implants than in GCF samples of healthy teeth (P = 0.003), and soluble receptor activator of nuclear factor-κB ligand (sRANKL) concentrations were significantly higher in the gingivitis than the mucositis group (P = 0.004). Biomarker levels were similar in peri-implantitis and periodontitis groups (P >0.05). Actinomyces naeslundi and Streptococcus oralis levels were significantly higher in the healthy implant group than in healthy teeth (P <0.05). Prevotella intermedia and Treponema denticola (Td) levels were lower in the mucositis group than the gingivitis group (P <0.05). Prevotella oralis and S. oralis levels were significantly higher in the periodontitis group (P <0.05), and Td levels were significantly higher in the peri-implantitis group (P <0.05).

CONCLUSION

There were many similarities but, crucially, some differences in biomarker levels (IL-1β and sRANKL) and bacterial species between peri-implant and periodontal sites in the same individuals, suggesting similar pathogenic mechanisms.

Assessment of Marginal Bone Loss around Platform-Matched and Platform-Switched Implants - A Prospective Study

The aim of the present study was to perform a software-assisted radiographic assessment of the effect of platform-switching on marginal bone loss (MBL) around dental implants. Forty patients requiring a dental implant in non-grafted partially edentulous mandibles were enrolled and categorized into implants receiving a platform-matched abutment (control group) or implants with a platform-switched abutment (test group). Standardized digital periapical radiographs were taken at the time of implant placement (T0), at implant loading (T1) and 1-year after functional loading (T2). Software-assisted radiographic assessment of the MBL horizontal, vertical and area changes was performed and compared between time intervals (T1-T0, T2-T1 and T2-T0). Mean radiographic horizontal MBL (hMBL) and vertical MBL (vMBL) from implant placement to 1-year after implant loading (T2-T0) were significantly increased around platform-matched when compared to platform-switched abutments (1.04 mm vs 0.84 mm, p<0.05) and (0.99 mm vs 0.82 mm, p<0.05), respectively. Additionally, bone loss area (BLa) was greater (0.77 mm2 vs 0.63 mm2; p<0.05) for platform-matched compared to platform-switched abutments. Platform-switching has a positive impact upon the amount of bone modeling after loading implants with internal hexagon connection.

A comparison of peri-implant strain generated by different types of implant supported prostheses

AIMS AND OBJECTIVE

To find out and compare peri implant strain developed in four different types of implant supported prostheses i.e., cement retained splinted, cement retained non splinted, screw retained splinted, screw retained non splinted.

METHODOLOGY

Four implant analogues were placed in a polyurethane mandibular model at the position of left and right first and second molar. Abutments were fixed to the implant at a torque of 25Ncm. Two such models were made. Four different prostheses were placed on abutment of each model i.e screw retained splinted, screw retained nonsplinted, cement retained splinted, cement retained non splinted. Four strain gauges were attached on the model, two on the buccal and two on the lingual aspect of each implant. Static load of 400N was applied on the prosthesis using universal testing machine. Load application was done ten times for each model and peri implant strain was measured.

RESULTS

The mean peri implant strain (±SD) generated was found to be highest in non-splinted screw retained (1397.70 ± 44.47 microstrains and 1265.90 ± 42.76 microstrains) and least in splinted cement retained (630.70 ± 31.98 microstrains and 519.60 ± 32.48 microstrains) in both 1st and 2nd molars respectively.

CONCLUSIONS

Splinted crowns produce less peri implant strain when compared to non splinted crowns. Cement retained prosthesis produce less peri implant strain when compared to screw retained prosthesis. Least strain was observed in cement retained splinted crowns.

Fixed Full Arches Supported by Tapered Implants with Knife-Edge Thread Design and Nanostructured, Calcium-Incorporated Surface: A Short-Term Prospective Clinical Study

Purpose. To evaluate implant survival, peri-implant bone loss, and complications affecting fixed full-arch (FFA) restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface. Methods. Between January 2013 and December 2015, all patients referred for implant-supported FFA restorations were considered for enrollment in this study. All patients received implants with a knife-edge thread design and nanostructured calcium-incorporated surface (Anyridge®, Megagen, South Korea) were restored with FFA restorations and enrolled in a recall program. The final outcomes were implant survival, peri-implant bone loss, biologic/prosthetic complications, and “complication-free” survival of restorations. Results. Twenty-four patients were selected. Overall, 215 implants were inserted (130 maxilla, 85 mandible), 144 in extraction sockets and 71 in healed ridges. Thirty-six FFAs were delivered (21 maxilla, 15 mandible): 27 were immediately loaded and 9 were conventionally loaded. The follow-up ranged from 1 to 3 years. Two fixtures failed, yielding an implant survival rate of 95.9% (patient-based). A few complications were registered, for a “complication-free” survival of restorations of 88.9%. Conclusions. FFA restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface are successful in the short term, with high survival and low complication rates; long-term studies are needed to confirm these outcomes.

Recent coating developments for combination devices in orthopedic and dental applications: A literature review

Orthopedic and dental implants have been used successfully for decades to replace or repair missing or damaged bones, joints, and teeth, thereby restoring patient function subsequent to disease or injury. However, although device success rates are generally high, patient outcomes are sometimes compromised due to device-related problems such as insufficient integration, local tissue inflammation, and infection. Many different types of surface coatings have been developed to address these shortcomings, including those that incorporate therapeutic agents to provide localized delivery to the surgical site. While these coatings hold enormous potential for improving device function, the list of requirements that an ideal combination coating must fulfill is extensive, and no single coating system today simultaneously addresses all of the criteria. Some of the primary challenges related to current coatings are non-optimal release kinetics, which most often are too rapid, the potential for inducing antibiotic resistance in target organisms, high susceptibility to mechanical abrasion and delamination, toxicity, difficult and expensive regulatory approval pathways, and high manufacturing costs. This review provides a survey of the most recent developments in the field, i.e., those published in the last 2-3years, with a particular focus on technologies that have potential for overcoming the most significant challenges facing therapeutically-loaded coatings. It is concluded that the ideal coating remains an unrealized target, but that advances in the field and emerging technologies are bringing it closer to reality. The significant amount of research currently being conducted in the field provides a level of optimism that many functional combination coatings will ultimately transition into clinical practice, significantly improving patient outcomes.

Peri-Implantitis Associated With a Pre-Existing Pathology

This case report presents a treatment of peri-implantitis associated with a pre-existing pathology. Peri-implantitis around implant #19 was detected from pus discharge upon probing. Guided bone regeneration was performed to treat the peri-implantitis with the administration of antibiotics. The histopathologic evaluation of soft tissue taken from the circumferential defect around the implant exhibited a cyst. The postsurgical CBCT and the follow-up radiograph confirmed the maturing bone graft and a reduced size of the defect around the implant.

A Prognosis System for Periimplant Diseases

INTRODUCTION

Periimplant diseases have slowly become a common complication in implant patients. Here, we present a prognosis system to aid clinicians and researchers in the evaluation and treatment of periimplant diseases. This prognosis system divides periimplant disease into favorable, questionable, unfavorable, and hopeless cases based on the level of bone loss, pocket depth, mobility, bleeding on probing, and suppuration.

MATERIALS AND METHODS

To test the accuracy of our prognostic scale, the authors designed and conducted a database search to compile articles allowing for testing of the proposed prognostic scale.

DISCUSSION

The literature search returned 101 articles, of which two reported all relevant values for the prognostic system and were used to evaluate its reliability and accuracy. The prognostic system correctly predicted the likely outcome of periimplant disease up to 1 year posttreatment for all examined implants.

CONCLUSIONS

The proposed prognostic system can be used as a tool for clinicians as they develop a treatment plan for all stages of periimplant disease.

Function of Platelet-Induced Epithelial Attachment at Titanium Surfaces Inhibits Microbial Colonization

The aim of this study was to evaluate the barrier function of platelet-induced epithelial sheets on titanium surfaces. The lack of functional peri-implant epithelial sealing with basal lamina (BL) attachment at the interface of the implant and the adjacent epithelium allows for bacterial invasion, which may lead to peri-implantitis. Although various approaches have been reported to combat bacterial infection by surface modifications to titanium, none of these have been successful in a clinical application. In our previous study, surface modification with protease-activated receptor 4–activating peptide (PAR4-AP), which induced platelet activation and aggregation, was successful in demonstrating epithelial attachment via BL and epithelial sheet formation on the titanium surface. We hypothesized that the platelet-induced epithelial sheet on PAR4-AP–modified titanium surfaces would reduce bacterial attachment, penetration, and invasion. Titanium surface was modified with PAR4-AP and incubated with platelet-rich plasma (PRP). The aggregated platelets released collagen IV, a critical BL component, onto the PAR4-AP–modified titanium surface. Then, human gingival epithelial cells were seeded on the modified titanium surface and formed epithelial sheets. Green fluorescent protein (GFP)–expressing Escherichia coli was cultured onto PAR4-AP–modified titanium with and without epithelial sheet formation. While Escherichia coli accumulated densely onto the PAR4-AP titanium lacking epithelial sheet, few Escherichia coli were observed on the epithelial sheet on the PAR4-AP surface. No bacterial invasion into the interface of the epithelial sheet and the titanium surface was observed. These in vitro results indicate the efficacy of a platelet-induced epithelial barrier that functions to prevent bacterial attachment, penetration, and invasion on PAR4-AP–modified titanium.

Treatment of periimplant mucositis: a systematic review of randomized controlled trials

OBJECTIVE

To determine the most effective treatment for periimplant mucositis in patients with dental implants compared with a control group.

MATERIALS AND METHODS

A PubMed (MEDLINE) literature search was made of articles published up until October 2013. Randomized controlled trials (RCTs) were stratified according to their level of quality using the Jadad scale and levels of evidence (University of Oxford).

RESULTS

The combinations of search terms resulted in a list of 371 titles. Of these, 114 references were finally reviewed. Finally, 7 RCTs fulfilled the inclusion criteria and were thus selected for inclusion in the systematic review. Chlorhexidine, the administration of azithromycin, and glycine powder air polishing are not effective for the treatment of periimplant mucositis. The only effective treatment seems to be the use of toothpaste with 0.3% triclosan.

CONCLUSION

Definitions of periimplant mucositis vary in the literature, and no clear criteria have been established regarding the diagnosis and treatment of this disorder. It highlights our lack of uniform treatment and need to establish additional research to fully provide effective treatments for this common condition. More, larger, and longer-term RCTs are needed in this periimplant disease.

A finite element analysis of novel vented dental abutment geometries for cement-retained crown restorations

Recent literature indicates that the long-term success of dental implants is, in part, attributed to how dental crowns are attached to their associated implants. The commonly utilized method for crown attachment - cementation, has been criticized because of recent links between residual cement and peri-implant disease. Residual cement extrusion from crown-abutment margins post-crown seating is a growing concern. This study aimed at (1) identifying key abutment features, which would improve dental cement flow characteristics, and (2) understanding how these features would impact the mechanical stability of the abutment under functional loads. Computational fluid dynamic modeling was used to evaluate cement flow in novel abutment geometries. These models were then evaluated using 3D-printed surrogate models. Finite element analysis also provided an understanding of how the mechanical stability of these abutments was altered after key features were incorporated into the geometry. The findings demonstrated that the key features involved in improved venting of the abutment during crown seating were (1) addition of vents, (2) diameter of the vents, (3) location of the vents, (4) addition of a plastic screw insert, and (5) thickness of the abutment wall. This study culminated in a novel design for a vented abutment consisting of 8 vents located radially around the abutment neck-margin plus a plastic insert to guide the cement during seating and provide retrievability to the abutment system.Venting of the dental abutment has been shown to decrease the risk of undetected residual dental cement post-cement-retained crown seating. This article will utilize a finite element analysis approach toward optimizing dental abutment designs for improved dental cement venting. Features investigated include (1) addition of vents, (2) diameter of vents, (3) location of vents, (4) addition of plastic screw insert, and (5) thickness of abutment wall.