Peri-implant diseases: diagnosis and risk indicators

Bimaxillary simultaneous immediate loading of full-arch restorations: A case series

Aim

To describe a bimaxillary simultaneous immediate loading protocol with full-arch implant-supported fixed prostheses.

Material and Methods

A prospective case series of 8 patients who required full-arch rehabilitation was conducted. The main inclusion criteria were patients with teeth that required extraction. At least 1 molar per arch was temporarily employed to stabilize the surgical template and the provisional prosthesis during intraoral relining.

Results

Two upper implants failed in 1 patient. Structural fracture was registered in 3 patients, around 3 months after loading. All of them had bruxism. Three esthetic complications were registered: midline deviation, canting of the oclusal plane and color mismatch.

Conclusions

Although this protocol achieves optimal results, some mechanical complications were encountered. The fracture of the provisional prosthesis is a relatively common mechanical complication but does not seem to jeopardize the final treatment result.

Key words:Implant-supported full-arch, provisional prosthesis fracture, bimaxillary simultaneous rehabilitation, conical abutments.

Prevalence and risk indicators of peri-implantitis in Korean patients with a history of periodontal disease: a cross-sectional study

Purpose

The aim of this study was to analyze the prevalence and risk indicators of peri-implantitis in Korean patients with history of periodontal disease.

Methods

A total of 444 patients with 1,485 implants were selected from patients who had been treated at the Department of Periodontology, Chonbuk National University Dental Hospital between July 2014 and June 2015. A group with a history of peri-implantitis (HP) (370 patients with 1,189 implants) and a group with a current peri-implantitis (CP) (318 patients with 1,004 implants) were created based on the radiographic and clinical assessments of implants. The prevalence of peri-implantitis was calculated at both the patient and implant levels. The influence of risk variables on the occurrence of peri-implantitis was analyzed using generalized estimating equations analysis.

Results

The prevalence of peri-implantitis in the HP and CP groups ranged from 6.7% to 19.7%. The cumulative peri-implantitis rate in the HP group estimated with the Kaplan-Meier method was higher than that in the CP group over the follow-up period. Among the patient-related risk variables, supportive periodontal therapy (SPT) was the only significant risk indicator for the occurrence of peri-implantitis in both groups. In the analysis of implant-related variables, implants supporting fixed dental prosthesis (FDP) and implants with subjective discomfort were associated with a higher prevalence of peri-implantitis than single implants and implants without subjective discomfort in the HP group. The presence of subjective discomfort was the only significant implant-related variable predictive of peri-implantitis in the CP group.

Conclusions

Within the limitations of this study, the prevalence of peri-implantitis in Korean patients with a history of periodontal disease was similar to that reported in other population samples. Regular SPT was important for preventing peri-implantitis. Single implants were found to be less susceptible to peri-implantitis than those supporting FDP. Patients' subjective discomfort was found to be a strong risk indicator for peri-implantitis.

Can degradation products released from dental implants affect peri-implant tissues?

This study aimed to assess the literature available on the effects, on peri-implant tissues, of degradation products released from dental implants as a consequence of therapeutic treatment for peri-implantitis and/or of wear-corrosion of titanium. A literature review of the PubMed medline database was performed up to December 31, 2016. The following search terms were used: "titanium wear and dental implant"; "titanium corrosion and dental implant"; "bio-tribocorrosion"; "peri-implantitis"; "treatment of peri-implantitis"; "titanium particles release and dental implant"; and "titanium ion release and dental implant". The keywords were applied to the database in different combinations without limits of time period or type of work. In addition, the reference lists of relevant articles were searched for further studies. Seventy-nine relevant scientific articles on the topic were retrieved. The results showed that pro-inflammatory cytokines, infiltration of inflammatory response cells and activation of the osteoclasts activity are stimulated in peri-implant tissues in the presence of metal particles and ions. Moreover, degenerative changes were reported in macrophages and neutrophils that phagocytosed titanium microparticles, and mutations occurred in human cells cultured in medium containing titanium-based nanoparticles. Debris released from the degradation of dental implants has cytotoxic and genotoxic potential for peri-implant tissues. Thus, the amount and physicochemical properties of the degradation products determine the magnitude of the detrimental effect on peri-implant tissues.

Clinical, radiological, and gene expression analyses in smokers and non-smokers, Part 2: RCT on the late healing phase of osseointegration

BACKGROUND

The mechanisms behind the impact of smoking on osseointegration are not fully understood.

PURPOSE

To investigate the initial clinical and molecular course of osseointegration of different implants in smokers and non-smokers in a randomized controlled trial (RCT).

MATERIALS AND METHODS

Smoking (n = 16) and non-smoking (n = 16) patients received 3 implant types: machined, oxidized, and laser-modified surfaces. Baseline bone biopsies were retrieved from the implant sites. After 60 and 90 days, the pain score, implant stability quotient (ISQ), and peri-implant crevicular fluid (PICF) gene expression were analyzed. Furthermore, radiological and clinical assessments were made at 90 days.

RESULTS

At 90 days, no pain was reported, irrespective of smoking habit. A higher ISQ was found in smokers compared with non-smokers. Marginal bone loss (MBL) was greater in smokers than in non-smokers. The comparison of implant surfaces revealed greater MBL exclusively at the machined implants in smokers. At 90 days in smokers, the PICF around machined implants revealed a higher expression of the proinflammatory cytokine, interleukin-6 (IL-6), and a lower expression of the osteogenic gene, osteocalcin (OC), compared with the PICF around modified implants. Furthermore, OC expression was lower at machined implants in smokers compared with machined implants in non-smokers. After adjustment for age and implant location (maxilla/mandible), multivariate regression revealed the following predictors of MBL: smoking, bleeding on probing at 90 days, hypoxia-inducible factor 1 alpha (HIF-1α) expression at baseline and IL-6 expression in PICF at 90 days.

CONCLUSIONS

During the early phase of osseointegration, non-smokers and smokers present a similar, high implant survival. In contrast, smokers present a greater MBL, particularly at machined implants. HIF-1α baseline expression in the recipient bone and IL-6 expression in PICF cells are important molecular determinants for MBL after 90 days. It is concluded that smoking has an early effect on osseointegration, which is dependent on the implant surface properties and the local host response.

Evaluation of Metalloproteinase-8 Levels in Crevicular Fluid of Patients with Healthy Implants or Periodontitis

Evaluation of periodontal and peri-implant tissue condition is mainly based on clinical examination and imaging diagnostics. Some data imply that Metalloproteinase-8 (MMP-8) level examination in peri-implant sulcular fluid (PISF) might be useful for evaluating the condition of peri-implant tissues and monitoring a development of peri-implant inflammation, including both mucositis and peri-implantitis. Hence, in this study, we decided to evaluate the level of MMP-8 in PISF obtained from patients without clinical symptoms of mucositis or peri-implantitis and compare it with MMP-8 level in gingival crevicular fluid (GCF) obtained from patients with healthy periodontium and those with varying severity of periodontitis. A total of 189 subjects were included in the study, and GCF/PISF samples were analysed for MMP-8 level by ELISA test. We documented that MMP-8 level in PISF obtained from patients without symptoms of mucositis or peri-implantitis was significantly higher not only than in GCF of periodontally healthy patients but also, which seems to be very interesting, than in GCF of patients with varying degrees of periodontal inflammation, consistent with earlier studies. Our observation might imply that monitoring of MMP-8 level in PISF could help to diagnose mucositis/peri-implantitis in an early stage, prior to clinical manifestations, which may allow for quick start of appropriate therapy.

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.

Influence of Laser-Microtextured Surface Collar on Marginal Bone Loss and Peri-Implant Soft Tissue Response: A Systematic Review and Meta-Analysis

BACKGROUND

A laser-microtextured surface (LMS) dental implant collar appears to promote a more tooth-like gingival collagen fiber attachment, which may help to stabilize peri-implant tissues. The purpose of this systematic review is to assess the clinical effect of an LMS versus non-LMS collar on crestal bone level and peri-implant soft tissue response.

METHODS

Electronic and manual literature searches were performed by two independent reviewers for articles written in English up to December 2016. Studies were included if they were human clinical trials with the purpose of evaluating the impact of an LMS collar on peri-implant hard and soft tissues. Cumulative marginal bone loss (MBL), probing depth (PD), and survival rate (SR) with 95% confidence intervals (CIs) were calculated to show the performance of LMS implant collars. MBL, PD, and SR data were analyzed with a random effects model to compare the influence of LMS collars with non-LMS collars (e.g., roughened surface and machined surface).

RESULTS

Fifteen human clinical studies (three randomized controlled trials, six cohort studies, and six case series) with 772 implants met the inclusion criteria. For the overall data, the weighted mean MBL was 0.72 mm (95% CI: 0.59 to 0.85 mm), PD was 1.81 mm (95% CI: 1.13 to 2.49 mm), and SR was 0.97 (95% CI: 0.95 to 0.98). MBL around an LMS collar was significantly less than around machined-surface collars (weighted mean difference [WMD]: -0.77; 95% CI: -1.01 to -0.52; I2 = 95.2%; P <0.001). PD in the LMS group was significantly shallower than in the machined-surface group (WMD: -1.34; 95% CI: -1.62 to -1.05; I2 = 81.4%; P <0.001). However, no statistically significant difference was detected for MBL between the LMS and roughened-surface groups (WMD: -0.04; 95% CI: -0.16 to 0.08; I2 = 0.0%; P = 0.75). No statistically significant difference was found for SR between the LMS and non-LMS groups (risk ratio: 1.01; 95% CI: 0.97 to 1.04; I2 = 0.0%; P = 0.91).

CONCLUSIONS

Meta-analysis showed that an LMS collar can reduce the amount of MBL and PD compared with a machined-surface collar. Due to high heterogeneity between the included studies, results should be interpreted cautiously.

Thermodynamic effects after Diode and Er:YAG laser irradiation of grade IV and V titanium implants placed in bone - an ex vivo study. Preliminary report

Many inserted implants are affected by peri-implantitis. The aim of our study was to evaluate increases in implant temperature, depending on the diameter and chemical composition of implants. In particular we measured the time it takes for the temperature of an implant to rise by 10°C and evaluated laser power settings required to prevent thermal injury when an implant surface is decontaminated during the treatment of peri-implantitis. The study analysed six implants placed in porcine ribs and divided into two groups according to their diameter and chemical composition (grade IV and grade V titanium). The implants were irradiated with Diode and Er:YAG lasers using different laser parameters. The temperature was measured with a K-type thermocouple. The temperature on the implant surface rose as the laser power increased and the implant diameter decreased. The time required to increase the temperature of an implant by 10°C was less than it was for titanium grade IV. The temperature gradient was below 10°C for all implants treated using a laser power up to 1 W. It is important to choose the correct laser parameters, depending on the chemical composition and diameter of the implant, so that decontamination of the implant surface is thorough, effective and safe.

Discomfort/pain due to periodontal and peri-implant probing: Implant type and age

AIM

There is evidence that patients experience more discomfort/pain after peri-implant probing than periodontal probing. However, there are several plausible factors to additionally influence this observation: e.g., implant type, age, smoking. Thus, this study was designed to compare discomfort/pain after periodontal and peri-implant probing in different implant types.

METHODS

Two dentists recruited and examined 80 patients, each of them exhibiting a dental implant with a contralateral natural tooth. Only two types of implants were included. Periodontal and peri-implant probing depths (PPD) and probing attachment level (PAL) were assessed. Whether implant or tooth were measured first was randomly assigned. Immediately after probing patients scored discomfort/pain using a visual analogue scale (VAS).

RESULTS

Eighty patients (median; lower/upper quartile: age 57; 47.5/65.5 years; 40 females, 11 smokers) were examined. With the exception of PPD and PAL at the deepest site as well as mean PPD (p < .05) clinical parameters (PAL, bleeding on probing, suppuration) were well balanced between implants and teeth. Peri-implant probing (VAS: 9.0; 5.0/17.0) caused significantly (p = .038) more discomfort/pain than periodontal probing (5.5; 2.0/13.5). This was confirmed by repeated measures analysis of variance adjusting for several factors (p = .011).

CONCLUSIONS

Peri-implant probing caused significantly more discomfort/pain than periodontal probing.

Gene expression in peri-implant crevicular fluid of smokers and nonsmokers. 1. The early phase of osseointegration

BACKGROUND

Smoking is a risk factor for dental implants. The mechanisms behind the impact of smoking on osseointegration are not fully understood.

PURPOSE

To investigate the initial molecular and clinical course of osseointegration of different titanium implants in smokers and nonsmokers.

MATERIALS AND METHODS

Smoker (n = 16) and nonsmoker (n = 16) patients were included. Each patient received three implant types: machined, oxidized and laser-modified surfaces. After 1, 7, 14, and 28 days, the peri-implant crevicular fluid (PICF) was sampled for gene expression analysis of selected factors involved in early processes of osseointegration. Furthermore, pain-score (VAS), resonance frequency analysis (RFA) and baseline clinical assessments were performed.

RESULTS

Early failure of osseointegration, associated with a high and sustained perception of pain, was encountered in 3/32 patients. In general, high pain scores were reported during the first days after implantation, irrespective to smoking habit, which correlated to high levels of pro-inflammatory cytokines during the first days after implantation. Higher ISQ values were found in smokers compared to nonsmokers. In smokers exclusively, ISQ values correlated to harder and less atrophic bone quality and quantity, respectively. Smokers displayed a higher expression of osteocalcin (OC), but later peak and lower expression of bone morphogenetic protein (BMP-2) (at 7 days) compared to nonsmokers. In comparison to machined implants, surface-modified implants were associated with higher expression of alkaline phosphatase (ALP) and cathepsin K (CatK) at 28 days in nonsmokers.

CONCLUSIONS

During the early phase of osseointegration, postoperative pain is linked to the inflammatory cell response and, may tentatively serve as an indicator of biological complication and implant loss. The present study suggests that smokers have an altered bone composition and (ultra)structure based on the observations that ISQ values are higher and correlate to recipient bone quality and quantity in smokers.

MMP13, TIMP2 and TGFB3 Gene Polymorphisms in Brazilian Chronic Periodontitis and Periimplantitis Subjects

Subjects susceptible to chronic periodontitis (CP) show a high risk for the development of periimplantitis (PI). Both diseases are multifactorial, presenting similarities in their pathophysiology and polygenic profile. MMP-13 (matrix metalloproteinases 13/ collagenase 3) is a collagenolytic enzyme, which expression is induced by TGF beta 3 (transforming growth factor type 3) in human gingival fibroblasts and inhibited by TIMP-2 (tissue inhibitor of metalloproteinase type 2). The aim of this study was to investigate the occurrence of periimplantitis (PI) in subjects with history of chronic periodontitis (CP) and polymorphisms frequency in MMP13, TIMP2 and TGFB3 genes. One hundred and sixty-three volunteers received dental implant placement were submitted to oral and radiographic examination in order to identify past history of CP or presence of PI. Volunteers were divided into 4 groups: Control (without PI and CP, n=72), CP (with CP and without PI, n=28), PI (with PI and without CP, n=28) and diseased (with CP and PI, n=35). The chi-square test correlated genotypes in specific regions of MMP13 (rs2252070), TIMP2 (rs7501477) and TGFB3 (rs2268626) genes, considering the interaction between CP and PI. The results showed that volunteers with CP had 3.2 times more susceptibility to develop PI (p=0.0004) compared to those without CP. No significant association was observed in MMP13, TIMP2 and TGFB3 genes with CP or PI. CP is a risk factor to develop PI, however, there is no association of both diseases with polymorphisms in the MMP13, TIMP2 and TGFB3 genes.

The role of IL-1 gene polymorphisms (IL1A, IL1B, and IL1RN) as a risk factor in unsuccessful implants retaining overdentures

PURPOSE

Implant-supported overdentures are an alternative predictable rehabilitation method that has a high impact on improving the patient's quality of life. However, some biological complications may interfere with the maintenance and survival of these overdenture implants. The goal of this article was to assess the factors that affect peri-implant success, through a hypothetical prediction model for biological complications of implant overdentures.

METHODS

A retrospective observational, prevalence study was conducted in 58 edentulous Caucasian patients rehabilitated with implant overdentures. A total of 229 implants were included in the study. Anamnestic, clinical, and implant-related parameters were collected and recorded in a single database. "Patient" was chosen as the unit of analysis, and a complete screening protocol was established. The data analytical study included assessing the odds ratio, concerning the presence or absence of a particular risk factor, by using binary logistic regression modeling. Probability values (p values) inferior to 0.05 were considered as representing statistically significant evidence.

RESULTS

The performed prediction model included the following variables: mean probing depth, metal exposure, IL1B_allele2, maxillary edentulousness, and Fusobacterium nucleatum. The F. nucleatum showed significant association with the outcome. Introducing a negative coefficient appeared to prevent complications or even boost the biological defense when associated with other factors.

CONCLUSIONS

The prediction model developed in this study could serve as a basis for further improved models that would assist clinicians in the daily diagnosis and treatment planning practice of oral rehabilitation with implant overdentures.

Erythritol/chlorhexidine combination reduces microbial biofilm and prevents its formation on titanium surfaces in vitro

BACKGROUND

The purpose of this in vitro study was to evaluate the antibiofilm activity of a novel air-polishing powder consisting of erythritol and chlorhexidine, assessing its ability to reduce previously grown microbial biofilm and to prevent biofilm formation on titanium surfaces.

METHODS

Clinical strains of Staphylococcus aureus, Pseudomonas aeruginosa, Bacteroides fragilis and Candida albicans isolated from peri-implantitis lesions were used. Biofilm was grown on sandblasted titanium discs and treated with erythritol/chlorhexidine. The antimicrobial activity was evaluated by determining the minimum inhibitory concentration and the minimum microbicidal concentration. The antibiofilm activity was assessed by semiquantitative spectrophotometric assay and by confocal laser scanning microscopy.

RESULTS

Erythritol/chlorhexidine displayed an inhibitory and a microbicidal activity against all the tested strains. The spectrophotometric analysis showed that the treatment was effective in both reducing the previously developed biofilm and decreasing biofilm formation on titanium surfaces. Confocal laser scanning microscopy analysis showed a significant reduction of the total biofilm volume, with an increase of the percentage of dead cells of all the microorganisms tested.

CONCLUSIONS

Erythritol/chlorhexidine displayed significant antimicrobial and antibiofilm activity against microorganisms isolated from peri-implantitis lesions. Due to its properties, it might represent a promising approach for the prevention and treatment of peri-implant diseases associated to microbial biofilm infections.

Evaluation of Clinical Soft Tissue Parameters for Extramaxillary Zygomatic Implants and Conventional Implants in All-on-4 Hybrid Rehabilitations: Short-Term Outcome and Proposal of Clinical Recommendations for Intervention in Recall Appointments

PURPOSE

This prospective cohort study aimed to investigate the short-term soft tissue clinical outcomes and recommendation for evaluation and follow-up after a new hybrid All-on-4 rehabilitation.

METHODS

Forty consecutively included patients rehabilitated in the complete edentulous atrophic maxillae through a hybrid All-on-4 treatment concept (4 immediate function implants in a combination between zygomatic and conventional implants). Periimplant conditions at zygomatic and conventional implants were compared. Four clinical levels (CLs) were used to classify the presence and severity of periimplant conditions.

RESULTS

Four patients withdrew from the study. No significant differences were found for periimplant conditions at zygomatic and conventional implants. The distribution was 28, 2, 1, and 9 patients with CL1, CL2, CL3, and CL4, respectively.

CONCLUSIONS

Soft tissue clinical outcomes of extramaxillary zygomatic implants and conventional implants seem to follow a similar distribution. The proposed classification system stratifies patients, supports decision making, and with further validation may elucidate recommendations for frequency of recall appointments and intervention to enhance long-term success.

Multidisciplinary Approach in the Management of a Complex Case: Implant-Prosthetic Rehabilitation of a Periodontal Smoking Patient with Partial Edentulism, Malocclusion, and Aesthetic Diseases

Complex periprosthetic cases are considered as challenges by clinicians. Clinical and radiographic parameters should be considered separately to make the right choice between an endodontically or periodontally compromised treated tooth and implant. Therefore, in order to decide whether the tooth is safe or not, data that have to be collected are specific parameters of both the patient and the clinician. In addition, the presence of periodontal, prosthetic, and orthodontic diseases requires patients to be set in multidisciplinary approach. The aim of this case report is to describe how the multidisciplinary approach could be the best way to manage difficult cases of implant-prosthetic rehabilitation. How to rehabilitate with fixed prosthesis on natural teeth and dental implants a smoker patient who presents with active periodontitis, multiple edentulous areas, dental malocclusion, and severe aesthetic problems was also described.

Bleeding on probing around dental implants: a retrospective study of associated factors

AIM

To (i) identify factors associated with the probability of a peri-implant site to be positive to bleeding on probing (BoP+) and (ii) compare BoP+ probability around dental implants and contra-lateral teeth.

METHODS

In 112 patients, data related to 1725 peri-implant sites and 1020 contra-lateral dental sites were retrospectively obtained. To analyse the association between patient-, implant- and site-related factors and BoP+ probability, a logistic, three-level model was built with BoP as the binary outcome variable (+/-).

RESULTS

BoP+ probability for a peri-implant site with probing depth (PD) of 4 mm was 27%, and the odds ratio increased by 1.6 for each 1-mm increment in PD (p < 0.001). Also, BoP+ probability was higher in females compared to males (OR = 1.61; p = 0.048), and lower at posterior compared to anterior dental implants (OR = 0.55; p < 0.01). No significant difference in BoP+ probability was observed between peri-implant and contra-lateral dental sites when controlling for the difference in PD.

CONCLUSIONS

The probability of a peri-implant site to bleed upon probing is (i) associated with PD, implant position and gender, and (ii) similar to that observed at contra-lateral dental sites when controlling for the effect of PD.

The impact of antimicrobial photodynamic therapy on peri-implant disease: What mechanisms are involved in this novel treatment?

According to the American Academy of Implant Dentistry, 3 million Americans have dental implants, and this number is growing by 500,000 each year. Proportionally, the number of biological complications is also increasing. Among them, peri-implant disease is considered the most common cause of implant loss after osseointegration. In this context, microorganisms residing on the surfaces of implants and their prosthetic components are considered to be the primary etiologic factor for peri-implantitis. Some research groups have proposed combining surgical and non-surgical therapies with systemic antibiotics. The major problem associated with the use of antibiotics to treat peri-implantitis is that microorganisms replicate very quickly. Moreover, inappropriate prescription of antibiotics is not only associated with potential resistance but also and most importantly with the development of superinfections that are difficult to eradicate. Although antimicrobial photodynamic therapy (aPDT) was discovered several years ago, aPDT has only recently emerged as a possible alternative therapy against different oral pathogens causing peri-implantitis. The mechanism of action of aPDT is based on a combination of a photosensitizer drug and light of a specific wavelength in the presence of oxygen. The reaction between light and oxygen produces toxic forms of oxygen species that can kill microbial cells. This mechanism is crucial to the efficacy of aPDT. To help us understand conflicting data, it is necessary to know all the particularities of the etiology of peri-implantitis and the aPDT compounds. We believe that this review will draw attention to new insights regarding the impact of aPDT on peri-implant disease.

Vitamin D deficiency in early implant failure: two case reports

An association between vitamin D deficiency and early dental implant failure is not properly verified, but its role in osteoimmunology is discussed. This article illustrates two case reports with vitamin D deficiency and early implant failure. Prior to implant placement, the first patient received crestal bone grafting with autologous material. Both patients received dental implants from different manufacturers in the molar region of the mandible. In the case of bone grafting in the first patient, all implants were placed in a two-stage procedure. All implants had to be removed within 15 days after implant placement. Vitamin D serum levels were measured: Both patients showed a vitamin D deficiency (serum vitamin D level <20 μg/l). After vitamin D supplementation, implant placement was successful in both patients. Prospective, randomized clinical trials must follow to affirm the relationship between vitamin D deficiency, osteoimmunology, and early implant failure.

Soft tissue augmentation around osseointegrated and uncovered dental implants: a systematic review

OBJECTIVES

The aim was to compile the current knowledge about the efficacy of different soft tissue correction methods around osseointegrated, already uncovered and/or loaded (OU/L) implants with insufficient soft tissue conditions. Procedures to increase peri-implant keratinized mucosa (KM) width and/or soft tissue volume were considered.

MATERIALS AND METHODS

Screening of two databases: MEDLINE (PubMed) and EMBASE (OVID), and manual search of articles were performed. Human studies reporting on soft tissue augmentation/correction methods around OU/L implants up to June 30, 2016, were considered. Quality assessment of selected full-text articles to weight risk of bias was performed using the Cochrane collaboration's tool.

RESULTS

Overall, four randomized controlled trials (risk of bias = high/low) and five prospective studies (risk of bias = high) were included. Depending on the surgical techniques and graft materials, the enlargement of keratinized tissue (KT) ranged between 1.15 ± 0.81 and 2.57 ± 0.50 mm. The apically positioned partial thickness flap (APPTF), in combination with a free gingival graft (FGG), a subepithelial connective tissue graft (SCTG), or a xenogeneic graft material (XCM) were most effective. A coronally advanced flap (CAF) combined with SCTG in three, combined with allogenic graft materials (AMDA) in one, and a split thickness flap (STF) combined with SCTG in another study showed mean soft tissue recession coverage rates from 28 to 96.3 %. STF combined with XCM failed to improve peri-implant soft tissue coverage.

CONCLUSIONS

The three APPTF-techniques combined with FGG, SCTG, or XCM achieved comparable enlargements of peri-implant KT. Further, both STF and CAF, both in combination with SCTG, are equivalent regarding recession coverage rates. STF + XCM and CAF + AMDA did not reach significant coverage.

CLINICAL RELEVANCE

In case of soft tissue deficiency around OU/L dental implants, the selection of both an appropriate surgical technique and a suitable soft tissue graft material is of utmost clinical relevance.

Survival of Brånemark System Mk III implants and analysis of risk factors associated with implant failure

The purpose of this study was to retrospectively investigate the outcomes of Brånemark System Mk III TiUnite/Groovy implants placed in patients at Kobe University Hospital. Various risk factors for implant failure, including mechanical coupling, were investigated by univariate and multivariate analysis. The predictive variables investigated included age, sex, smoking habit, general health, history of radiation therapy, application of a dentomaxillary prosthesis, type of prosthesis, use of alveolar bone augmentation, site of implant insertion, mechanical coupling between implants, and the length and diameter of the implants. Of the 907 implants investigated, only 23 were unsuccessful; the overall survival rate was 96.7%. Increased age, radiation therapy, application of a removable prosthesis or dentomaxillary prosthesis, lack of mechanical coupling between implants, and shorter implants (≤8.5mm) were significant risk factors for implant failure according to univariate analysis (P<0.05). Multivariate analysis identified a significant association (P<0.05) between dental implant failure and a lack of mechanical coupling between implants (odds ratio 6.88) and shorter implants (≤8.5mm) (odds ratio 3.43). The findings of this study demonstrated multivariate relationships between various risk factors and dental implant failure.

Occlusal trauma and mucositis or peri-implantitis?

BACKGROUND AND OVERVIEW

The aim of this study was to describe the effects of bruxism in peri-implant bone loss 6 years after the placement of a successful implant-supported prosthesis, to describe its treatment, and to propose a differential diagnosis of the lesion.

CASE DESCRIPTION

A 62-year-old, nonsmoking, systemically healthy partially edentulous woman received 2 osseointegrated implants in the mandibular left region, which supported a 3-element fixed prosthesis. Six years later, the patient reported the development of bruxism. Clinical examination results indicated bleeding on probing, deepening of the peri-implant sulcus, and marginal soft-tissue overgrowth. Radiographic images suggested peri-implant bone loss. The authors diagnosed the lesion as trauma from occlusion and mucositis. Treatment involved anti-infective therapy and the use of a bite platform, resulting in bone recovery after 10 months. These results were maintained for 4 years.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Considering the existing contradictions in the literature, this case highlights the role of trauma from occlusion in the onset, progression, and treatment of lesions produced by occlusal overload around osseointegrated implants. In addition, it provides clinical background on the outcomes of anti-infective therapy associated with the use of a bite platform in the treatment of combined lesions of mucositis and trauma from occlusion in osseointegrated implants.

Saving Single-rooted Teeth with Combined Endodontic-periodontal Lesions

INTRODUCTION

Teeth affected by combined endodontic-periodontal lesions are usually considered by all prognosis classifications as hopeless teeth. The development of new biomaterials combined with modern endodontic and periodontal regeneration techniques may improve dental prognosis and maintain the affected teeth. Moreover, 1 of the replacement options for those teeth, dental implants, has shown an increasing number of biological and technical complications.

METHODS

Five patients were included in this case series study. Full periodontal and radiographic examination revealed generalized chronic periodontitis. Moreover, endodontic-periodontal lesions affecting single-rooted teeth were detected in those patients with tissue destruction beyond the apex. After splinting those teeth, conventional endodontic and nonsurgical periodontal treatment was performed. Three months later, periodontal regeneration was applied at those teeth in order to reconstruct supporting tissues and to improve dental prognosis.

RESULTS

After a follow-up period ranging from 14 months to 17 years, it was observed that all teeth remain asymptomatic and in normal function. No signs of apical pathosis were observed, and the periodontium was stable. All patients were included in a strict maintenance program to check the periodontal and apical status.

CONCLUSIONS

This case series shows that it is possible to change the prognosis of teeth affected by combined endodontic-periodontal lesions, even if the periodontal support is destroyed beyond the apex.

Influence of Peri-Implant Soft Tissue Condition and Plaque Accumulation on Peri-Implantitis: a Systematic Review

OBJECTIVES

To systematically examine influence of soft tissue condition and plaque accumulation around dental implants on peri-implantitis development.

MATERIAL AND METHODS

An electronic literature search was conducted of two databases - MEDLINE (Ovid) and EMBASE from 2011 to 2016. Sequential screenings at the title, abstract, and full-text levels were performed. Clinical human studies in the English language that had reported soft tissue condition or plaque accumulation influence on peri-implantitis development were included. The resulting articles were independently subjected to clear inclusion and exclusion criteria by two reviewers as follows.

RESULTS

The search resulted in 8 articles meeting the inclusion criteria. These studies reported gingival index, plaque index, pocket depth, bleeding on probing/modified bleeding index for sites with "adequate" (≥ 2 mm) and "inadequate" (< 2 mm) width of keratinized mucosa. Results demonstrated that the amount of keratinized mucosa has little influence on soft-tissue inflammation in the presence of good oral hygiene. However, suboptimal oral hygiene due to difficulty in access for plaque control in the areas of minimal keratinized mucosa may lead to greater tissue damage.

CONCLUSIONS

In cases with insufficient keratinized gingiva in the vicinity of implants, the insufficiency does not necessarily mediate adverse effects on the hygiene management and soft tissue health condition. Nonetheless, the risk of the increase of gingival index, plaque index, pocket depth, bleeding on probing/modified bleeding index is present. Therefore, the presence of an appropriate amount of keratinized gingiva is required.

Risk indicators related to peri-implant disease: an observational retrospective cohort study

Purpose

The aim of the present study was to retrospectively investigate the influence of potential risk indicators on the development of peri-implant disease.

Methods

Overall, 103 patients referred for implant treatment from 2000 to 2012 were randomly enrolled. The study sample consisted of 421 conventional-length (>6 mm) non-turned titanium implants that were evaluated clinically and radiographically according to pre-established clinical and patient-related parameters by a single investigator. A non-parametric Mann-Whitney U test or Kruskal-Wallis rank test and a logistic regression model were used for the statistical analysis of the recorded data at the implant level.

Results

The diagnosis of peri-implant mucositis and peri-implantitis was made for 173 (41.1%) and 19 (4.5%) implants, respectively. Age (≥65 years), patient adherence (professional hygiene recalls <2/year) and the presence of plaque were associated with higher peri-implant probing-depth values and bleeding-on-probing scores. The logistic regression analysis indicated that age (P=0.001), patient adherence (P=0.03), the absence of keratinized tissue (P=0.03), implants placed in pristine bone (P=0.04), and the presence of peri-implant soft-tissue recession (P=0.000) were strongly associated with the event of peri-implantitis.

Conclusions

Within the limitations of this study, patients aged ≥65 years and non-adherent subjects were more prone to develop peri-implant disease. Therefore, early diagnosis and a systematic maintenance-care program are essential for maintaining peri-implant tissue health, especially in older patients.

Chemical, microscopic, and microbiological analysis of a functionalized poly-ether-ether-ketone-embedding antibiofilm compounds

Poly-ether-ether-ketone (PEEK) is currently introduced as an alternative material for orthopedic implants due to its biocompatibility and low elastic modulus compared to titanium. Also, a sulphonation treatment can functionalize PEEK to embed therapeutical substances. The objective of this work was to functionalize a PEEK film to incorporate novel lactam-based antibiofilms compounds. PEEK samples were functionalized by sulphuric acid treatment and then dissolved in dimethylsulfoxide, where lactams were added to be incorporated into the polymer. A dip-coating technique was used to synthesize a thin film on a glass-based substrate. The degree of sulfonation (DS) and the incorporation of lactams into sulphonated PEEK (sPEEK) were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA), and scanning electron microscopy. A DS of 65% was obtained and TGA curves confirmed the presence of SO₃ H and lactams in the sPEEK structure. The growth of Streptococcus mutans biofilm decreased on sPEEK surface containing lactams when compared to sPEEK free of lactams. That indicated the antibiofilm activity of those compounds was maintained after incorporation into sPEEK. Planktonic growth analysis showed no long distant effects of sPEEK containing lactams, indicating that no systemic effects should be expected upon clinical uses of medical devices produced with lactam-treated sPEEK. Results revealed that inclusion of lactams into sPEEK represents a good alternative for the production of biomaterials resistant to bacterial accumulation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3015-3020, 2016.

Patient satisfaction 8-14 years after dental implant therapy - a questionnaire study

OBJECTIVE

The aim of this questionnaire study was to investigate patient satisfaction 8-14 years after dental implant therapy and complications influencing the degree of satisfaction.

MATERIALS AND METHODS

A questionnaire was sent by post to 587 patients at a specialist clinic of periodontology. The questionnaire consisted of 19 statements or questions such as the degree of satisfaction with the implants and knowledge of complications. In nine of the questions, respondents were asked to grade the extent of their agreement with a statement by selecting from fixed answers. Three of the questions were designed to be answered using a visual analog scale.

RESULTS

In total, 400 individuals (81%) responded to the questionnaire. The mean time elapsed since implant installation was 10 years. A great majority (81%) experienced a high chewing comfort and was satisfied or sufficiently satisfied (94%) with the aesthetic aspects of their implant restorations, while 32% of the individuals had experienced problems with their implant reconstructions. The disadvantage that patients remarked on was the cost of the treatment. Those who had experienced problems with their implant reconstructions were also less satisfied with the treatment.

CONCLUSION

A great majority of the patients expressed a high degree of satisfaction with their dental implants 8-14 years after the treatment. Patients were less satisfied if they had experience of problems with their implant reconstructions and in cases when the clinicians were unable to resolve their complications.

Peri-Implant Crevicular Fluid Analysis, Enzymes and Biomarkers: a Systemetic Review

OBJECTIVES

To review the current understanding of the biomarkers and enzymes associated with different forms peri-implant diseases and how their level changes influence the pathogenesis of the inflammatory diseases around dental implants.

MATERIAL AND METHODS

An electronic search in two different databases was performed including MEDLINE (PubMed) and EMBASE between 1996 to 2016. Human studies analyse peri-implant crevicular fluid (PICF) biomarker and enzyme levels of implants having peri-implant mucositis and peri-implantitis published in English language, were evaluated. A systematic review was performed to assess which biomarkers and enzymes in PICF were used to identify the inflammatory conditions around dental implants.

RESULTS

Fifty-one articles were identified of which 41 were further evaluated and included in the analysis. Due to significant heterogeneity between included studies, a meta-analysis could not be performed. Instead, a systematic descriptive review was performed.

CONCLUSIONS

Biomarkers and enzymes in peri-implant crevicular fluid have shown promising results in differentiating from peri-implant disease condition to health. However, due to inconsistent results and acquiring much evidence from cross-sectional studies, additional evidence supported by randomized-controlled trials is needed to validate the links reported.

Bone stability around implants in elderly patients with reduced bone mineral density - a prospective study on mandibular overdentures

OBJECTIVE

The purpose of this prospective clinical study was to determine whether reduced bone mineral density (BMD) is correlated with a higher risk for dental implant therapy in an elderly patient population.

MATERIAL AND METHODS

Seventy-nine patients recruited at the Prince Philip Dental Hospital were provided with 2-implant-supported mandibular overdentures. Skeletal BMD was recorded before the implant therapy. The World Health Organization Osteoporosis Diagnosis Classification (femoral neck score) was utilized to define the osteoporosis status of patients. Periapical radiographs were taken with a special radiographic holder at the time of implant loading (baseline) and at follow-up examinations. The mesial and distal marginal bone levels of each implant were measured. The mean marginal bone loss (mMBL) and greatest marginal bone loss (GBL) of four implant sites at patient level were recorded for data analysis. Clinical examination including plaque score (PI) and bleeding on probing (BOP) was recorded.

RESULTS

Of the 79 patients recruited in the study, the survival rate of implant was 98.7%. Sixty-three patients (79.7%) were finally available for data collection and statistical analyses. The mean follow-up time was 62.9 (SD = 15.2) months with the mean MBL 0.65 mm (SD = 0.67) and mean GBL 1.25 mm (SD = 0.83), respectively. The average BOP and PI of patients were 49.6% (SD = 30.8) and 47.4% (SD = 37.4). Only BOP was found significantly correlated with mMBL (r = 0.321, P = 0.01). Skeletal BMD was not associated with marginal bone loss (mean MBL: r = -0.094, P = 0.466; mean GBL: r = 0.04, P = 0.761).

CONCLUSIONS

Within the limits of this study, osteoporosis was not a contraindication for implant therapy, and reduced skeletal BMD was not associated with increased marginal bone loss around implants or other complications in an elderly population.

Peri-implant disease: what we know and what we need to know

Peri-implant disease is a serious problem that plagues today's dentistry, both in terms of therapy and epidemiology. With the expansion of the practice of implantology and an increasing number of implants placed annually, the frequency of peri-implant disease has greatly expanded. Its clinical manifestations, in the absence of a globally established classification, are peri-implant mucositis and peri-implantitis, the counterparts of gingivitis and periodontitis, respectively.

However, many doubts remain about its features. Official diagnostic criteria, globally recognized by the dental community, have not yet been introduced. The latest studies using metagenomic methods are casting doubt on the assumption of microbial equivalence between periodontal and peri-implant crevices. Research on most of the features of peri-implant disease remains at an early stage; moreover, there is not a commonly accepted treatment for it. In any case, although the evidence so far collected is limited, we need to be aware of the current state of the science regarding this topic to better understand and ultimately prevent this disease.

Impact of a chronic smoking habit on the osteo-immunoinflammatory mediators in the peri-implant fluid of clinically healthy dental implants

OBJECTIVE

The aim of this study was to evaluate the influence of chronic cigarette smoking on the profile of osteo-immunoinflammatory markers in the peri-implant crevicular fluid (PICF) from clinically healthy implants DESIGNS: Twenty-five smokers and 23 non-smoker subjects with a unitary screwed implant-supported crown in the molar or pre-molar region were enrolled in this study. The implants should have been in functioning for at least 12 months, and the peri-implant tissue should be clinically healthy [probing depth (PD)<4mm with no bleeding on probing (BoP) and no evidence of radiographic bone loss beyond bone remodeling]. The levels of interferon (INF)-γ, interleukin (IL)-4, IL-17, IL-1β, IL-10, IL-6, IL-8, tumor necrosis factor (TNF)-α, matrix metalloproteinase (MMP)-2, MMP-9, osteoprotegerin (OPG), soluble receptor activator of nuclear factor-κβ ligand (RANKL), osteocalcin (OC), osteopontin (OPN), transforming growth factor (TGF)-β, and cross-linked telopeptide of type I collagen (ICTP) in the PICF were quantified by a multiplexed bead immunoassay.

RESULTS

The smokers presented reduced levels of IL-4, IL-8, and TNF-α compared with the non-smoker individuals (p<0.05). In addition, although lower OPG levels were detected in the PICF of the smokers, the RANKL/OPG ratio did not show a significant difference (p>0.05). Moreover, higher ICTP concentrations and a higher TH1/TH2 ratio were observed in the PICF of the smoker patients (p<0.05). No differences between the groups were observed for the other markers evaluated (p>0.05).

CONCLUSIONS

Smoking habit modulate peri-implant cytokine profile, leading to reductions in IL-4, -8 TNF-α, and OPG levels and an increased ICTP and TH1/TH2 ratio in peri-implant crevicular fluid.