The subgingival microbial flora associated with human dental implants

Ramus Frame Dental Implant Functional Survival and Safety in Severely Atrophic Edentulous Human Mandibles

Ramus frame dental implants were retrospectively studied in 360 adults with severely atrophic edentulous mandibles. Patient records up to 12 years post-treatment were independently reviewed after a single clinician surgically placed titanium long-arm ("Tatum") ramus frame implants and immediately loaded them with a mandibular overdenture. A total of 11 ramus frames were removed at 19 to 109 months post-treatment, mostly due to supramucosal bar fracture (N = 6) or mobility (N = 3). Kaplan-Meier product-limit analysis revealed the post-treatment survival probability for functional ramus frame implants to be 99.3% at 2 years (266 patients), 98.9% at 3 years (223 patients), 97.9% at 4 years (198 patients), 96.9% at 5 years (160 patients), 96.9% at 6 years (123 patients), 95.0% at 7 years (86 patients), 95.0% at 8 years (67 patients), 93.3% at 9 years (43 patients), and 91.1% at 10 years (25 patients). No statistically significant differences in functional ramus frame implant survival were found relative to patient gender, smoking, presence of natural maxillary teeth, or compliance with semi-annual maintenance care. Fracture of endosseous anterior feet/posterior arms was the most frequent implant-related complication on 29 implants, which were left in place, repaired, or replaced in situ without implant removal. At 5 years, the ramus frame implant functional survival probability without any implant-related biological or mechanical complication was 88.9%. Ramus frame dental implants, immediately loaded with a fully implant-borne mandibular overdenture, exhibited a high degree of long-term functional survival and safety in severely atrophic edentulous human mandibles.

Current Concepts on the Pathogenesis of Peri-implantitis: A Narrative Review

As implant treatment has been integrated in contemporary dental practice, complications with the forms of peri-implant mucositis and peri-implantitis have also increased in prevalence. Peri-implantitis is the more severe biological complication and is defined as an inflammatory disease affecting peri-implant tissues resulting in bone and eventually implant loss. In addition, the treatment of peri-implantitis has currently become a substantial global economic burden. In the current study, a search was conducted in several electronic databases using specific keywords relevant to the article's main topic. An increasing number of scientific reports have investigated the etiopathology of peri-implant diseases, focusing mainly on peri-implantitis. Microbial biofilm consists an important etiological factor of peri-implant pathology analogous to periodontal diseases. Although several data confirm that peri-implant infections are dominated by gram-negative bacteria, similar to periodontal infections, there is evidence that some cases may harbor a distinct microbiota, including opportunistic microorganisms and/or uncultivable species. Additionally, data support that several parameters, such as genetic predisposition of individual patients, occlusal overload, and local factors such as titanium particles and excess cement, may be implicated in peri-implantitis pathogenesis. Simultaneously, the release of titanium metal particles and their biological consequences or the presence of excess cement in the adjacent peri-implant tissues have also been suggested as factors that contribute to peri-implant pathology. A specific line of research also indicates the role of foreign body response to implant installation. This narrative review aims to discuss the current concepts of etiopathogenetic factors implicated in peri-implantitis.

Evaluation of subgingival microbiota around single tooth implants

Objectives

1. To provide information about the subgingival microbiota around single tooth implants.2. To assess the subgingival microbial flora around the teeth adjacent to single tooth implants.3. To clinically evaluate the gingival health surrounding the single-tooth implants.

Methods

Patients undergoing the single-tooth implant replacements, were selected as subjects for the study. The natural teeth adjacent to implant sites were taken as control sites. Clinically each peri-implant gingival tissue health was evaluated. Subgingival plaque samples were removed with sterile curette and evaluated for microbial flora, by microscopic examinations. Bacterial cultures of samples studied. The similar procedure was followed for the control sites also. Finally the data collected were statistically analyzed and interpreted.

Results

The subgingival microbiota around single tooth implants was cultured and studied. Enterobacter species, Klebsiella pneumonia, Pseudomonas aeruginosa and Streptococcus species were predominantly found. Klebsiella pneumonia and Pseudomonas aeruginosa were found more frequently around implant sites than control sites. Anaerobic Bacteroides species were found in only one case around the implant site.

Conclusions

Prevention and control of bacterial infection in the peri-implant region are among the key factors in determining the long term success or failure of dental implant therapy. The thorough knowledge about the subgingival microbiota around the healthy and diseased peri-implant mucosa is needed to determine the overall outcome of implant therapy.

Targeted Drug Delivery from Titanium Implants: A Review of Challenges and Approaches

Titanium implants are considered the gold standard of treatment for dental and orthopedic applications. Biocompatibility, low elasticity, and corrosion resistance are some of the key properties of these metallic implants. Nonetheless, a long-term clinical failure of implants may occur due to inadequate osseointegration. Poor osseointegration induces mobility, inflammation, increased bone resorption, and osteolysis; hence, it may result in painful revision surgeries. Topographical modifications, improvement in hydrophilicity, and the development of controlled-release drug-loading systems have shown to improve cellular adhesion, proliferation, and differentiation. Surface modifications, along with drug coating, undoubtedly demonstrate better osseointegration, especially in challenged degenerative conditions, such as osteoporosis, osteoarthritis, and osteogenesis imperfecta. Anabolic bone-acting drugs, such as parathyroid hormone peptides, simvastatin, prostaglandin-EP4-receptor antagonist, vitamin D, strontium ranelate, and anti-catabolic bone-acting drugs, such as calcitonin, bisphosphonates, and selective estrogen receptor modulators, expedite the process of osseointegration. In addition, various proteins, peptides, and growth factors may accessorize the idea of localized therapy. Loading these substances on modified titanium surfaces is achieved commonly by mechanisms such as direct coating, adsorption, and incorporating in biodegradable polymers. The primary approach toward the optimum drug loading is a critical trade-off between factors preventing release of a drug immediately and those allowing slow and sustained release. Recent advances broaden the understanding of the efficacy of adsorption, hydrogel coating, and electrospinning layer-by-layer coating facilitated by differential charge on metallic surface. This review discusses the existing approaches and challenges for the development of stable and sustained drug delivery systems on titanium implants, which would promote faster and superior osseointegration.

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.

Influence of different forms and materials (zirconia or titanium) of abutments in peri-implant soft-tissue healing using matrix metalloproteinase-8: A randomized pilot study

STATEMENT OF PROBLEM

It is unclear how pathogenic bacteria adhere to different implant materials and whether biomarker matrix metalloproteinase-8 (MMP-8) level provides a reliable method of evaluating the connective tissue status of peri-implant tissues.

PURPOSE

The purpose of this pilot clinical study was to evaluate peri-implant connective tissue response by assessing the MMP-8 levels in peri-implant crevicular fluid around titanium and zirconia abutments.

MATERIAL AND METHODS

The study was designed as a prospective, within-subject comparison with left-right randomization low. Twelve participants with partial edentulism were selected according to inclusion and exclusion criteria. Peri-implant sulcal fluid sampling and pocket probing depths were assessed at 1, 3, and 12 months after placing the abutments. The MMP-8 protein level of the peri-implant sulcal fluid was determined by MMP-8-specific sandwich enzyme-linked immunosorbent assay system. The independent t test or Wilcoxon test was used to compare MMP-8 levels and probing depth assessment between the zirconia and titanium groups at different time points (1, 3, and 12 months). Repeated measures ANOVA was used for within-group comparison of the MMP-8 levels at 3 time points (α=.05).

RESULTS

At 1 and 3 months, the titanium abutments showed significantly higher MMP-8 levels and probing depths than the zirconia abutments (P<.05), but no significant differences were found at 12 months for either variable (P>.05).

CONCLUSIONS

This study suggests the presence of more remodeling and/or inflammatory phenomena around titanium implant abutments than around zirconia abutments of a different design during the early stages but not at 1 year.

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.

Factors Influencing the Soft Tissue Changes Around Single Laser Microtextured Implants-Abutments in the Anterior Maxilla: A 5-Year Retrospective Study

PURPOSE

The aim of this study was to evaluate the possible factors that influenced the periimplant soft tissue changes around single implants-abutments with laser-microtextured surface (LMS) in the esthetic zone.

MATERIALS AND METHODS

Thirty-nine units, formed by implant-abutment with LMS were studied. Variables possibly associated with the periimplant soft tissue changes were obtained from clinical measurements (plaque [present/absent], periimplant biotype [thin/thick], and probing depth); intrasurgical measurements (vertical height in millimeters of the keratinized gingiva in the vestibular part of the implant site vestibular keratinized gingiva [VKG], implant vestibular crestal exposition, vestibular crestal level, and vestibular bone width); cast models (implant position [buccal/palatal], implant abutments angle); periapical radiographs (distance from the contact point to the interproximal bone crest of the adjacent tooth [CP-BC], distance from the contact point to the implant platform [CP-P], distance from the contact point to the first bone to implant contact [CP-IB]); and digital clinical photographs. Fisher exact test was used to determine the influence of each factor on the papilla level and on the facial marginal mucosal level.

RESULTS

The papillae level at the implant sites was significantly associated with the distance from the contact point to the alveolar bone crest, whereas no association was found with other variables. Periimplant biotype, differences in the VKG, CP-BC, and CP-IB were found associated with the different facial marginal mucosal level groups.

CONCLUSIONS

This study showed that the papilla level at single-tooth implants-abutments with LMS in the anterior maxilla was mainly influenced by the interproximal bone crest level of the adjacent tooth, whereas the marginal mucosal level was affected by periimplant biotype, facial bone crest level, and crestal implant exposition.

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.

Periodontal and peri-implant microbiota in patients with healthy and inflamed periodontal and peri-implant tissues

OBJECTIVE

To compare the prevalence and levels of six bacterial pathogens within the subgingival/submucosal microbiota at teeth versus implants with various clinical conditions.

MATERIAL AND METHODS

Twenty-two Chinese were included. Four subgingival/submucosal sites were selected for microbiological sampling within each subject, that is, (1) healthy peri-implant tissues; (2) peri-implantitis [PPD ≥ 5 mm, presence of bleeding on probing (BOP) and confirmed radiographic bone loss]; (3) healthy gingiva; and (4) periodontitis (PPD ≥4 mm). Subgingival/submucosal plaque was sampled using paper points. Quantitative real-time polymerase chain reaction (q-PCR) was used to quantify six pathogens, including Porphyromonas gingivalis (P.g.), Treponema denticola (T.d.), Aggregatibacter actinomycetemcomitans (A.a.), Fusobacterium nucleatum (F.n.), Prevotella intermedia (P.i.), and Staphylococcus aureus (S.a.). Counts were log10-transformed.

RESULTS

The most commonly detected species were S. a. and F. n., while A. a. and. P. i. had the lowest detection frequency. The detection frequencies of diseased tooth or implant sites for each of the six target species were either equal to or higher than the respective frequencies at the corresponding healthy sites. There were no statistically significant differences for any of the species or clinical sites (P > 0.05, Cochran's Q test). No statistically significant differences in the bacterial loads were found among the four clinical sites; with the exception of F. nucleatum. This was more abundant in periodontitis sites (P = 0.023, Friedman's 2-way anova). Both periodontal and peri-implant sites, irrespective of their health status, were revealed to harbor S. aureus cells. The log10-transformed loads of S. aureus were approximately 3.5 within each of the clinical sites (P = 0.232). This was the highest of the six species analyzed.

CONCLUSIONS

Within the same subjects, putative periodontal pathogens were common to both periodontal and peri-implant sites irrespective of health status. The prevalence and levels of P. gingivalis and F. nucleatum were significantly associated with periodontitis, but not with peri-implantitis. A. actinomycetemcomitans was associated with both disease conditions, periodontitis and peri-implantitis, but not with either gingival or mucosal health.

Taurolidine as an effective and biocompatible additive for plaque-removing techniques on implant surfaces

OBJECTIVES

The aim of the present study was the evaluation of the effectiveness and efficiency of two plaque-removing techniques, plastic curettes (PC) and glycine powder airflow (GLY) in combination with taurolidine (T), chlorhexidine (CHX), or pure water (PW) as additives and compared to groups without previous treatment (NT).

MATERIALS AND METHODS

Plaque was collected on titanium samples for 48 h in six subjects. Specimens were worn in a special splint in the upper jaw and randomly assigned to test and control groups. After biofilm removal procedures, clean implant surface (CIS) on the samples and treatment time were taken as parameters.

RESULTS

Mean CIS was determined in the following descending order: T-GLY > CHX-GLY > NT-GLY > T-PC > PW-GLY > PW-PC > CHX-PC > NT-PC. Mean treatment time was determined in the following ascending order: T-GLY < CHX-GLY < PW-GLY < NT-GLY < T-PC < CHX-PC < PW-PC < NT-PC.

CONCLUSIONS

Within the limits of this study, it can be concluded that T showed the highest CIS in the GLY and PC groups. T-GLY showed significantly more CIS than all other GLY groups. The T-PC group showed significantly more CIS than all other PC groups. The treatment times of the T groups were significantly lower than their corresponding PC or GLY groups.

CLINICAL RELEVANCE

The results of the current study indicate that taurolidine seems to enhance effectiveness of plaque-removing procedures with plastic curettes and glycine powder airflow. Also, the efficiency of both treatment procedures seems to be increased.

Soft tissue conditions and marginal bone levels of implants with a laser-microtextured collar: a 5-year, retrospective, controlled study

AIM

To compare clinical and radiographic outcomes of implants with a Laser-Lok®-microtextured collar to implants with a resorbable blast textured (RBT) collar after a 5-year follow-up period.

MATERIALS AND METHODS

Thirty-four implants with a Laser-Lok®-microtextured collar (test group [TG]) and 31 implants with an RBT collar (control group [CG]) were placed in 45 non-smoking, periodontally healthy patients. The full-mouth plaque score, full-mouth bleeding score, number of sites with plaque, and the number of sites with bleeding on probing (BOP) were recorded at baseline, and at 1-, 2-, 3-, 4-, and 5-year follow-up. Probing depth (PD) and mucosal recession were assessed at baseline and after the 5-year follow-up period. The radiographic marginal bone loss (MBL) was calculated by subtracting the bone level at the time of crown insertion from the bone level at the 5-year follow-up.

RESULTS

An implant survival rate of 94% and of 90% was reported for the TG and the CG, respectively. No statistical differences were found between the study groups for presence of plaque (10.1% vs. 25%) or for number of sites with BOP (10.3% vs. 23%). The differences between both study groups were statistically significant for mean MBL (0.81 ± 0.24 vs. 2.02 ± 0.32 mm), mean PD (2.32 ± 0.44 vs. 4.25 ± 0.87 mm), and mean mucosal recession (0.16 ± 0.3 vs. 0.22 ± 0.3 mm).

CONCLUSIONS

Within the limitations of this study, results suggest that the laser-microtextured implant collar surface may provide more favorable conditions for the attachment of hard and soft tissues, and reduce the level of MBL.

Microflora around teeth and dental implants

Background:

When an implant is exposed to oral cavity, its surface gets colonized by micro-organisms. The aim of this study is to comparatively assess the microbiological parameters in sulci around the teeth and the crowns supported by dental implants.

Materials and Methods:

In this prospective, cross-sectional study, 34 partially edentulous patients aged between 40 and 50 years with total 50 anterior maxillary single implants with cemented crowns (depth of sulci <4 mm) and 34 similar teeth in the same jaw of the same patients were included. Excluded were the patients with compromised systemic and periodontal health and smoking habits. None of the patients had used any antimicrobial mouthwashes during at least two weeks before the study. All of the implants (ITI) were at least 6 months in place covered by definitive prostheses. Samples of gingival sulci were taken around teeth with paper cone and transported to Stuart transport medium. Samples were cultured and examined by a dark field microscope and eight laboratory tests were performed to determine the micro-organisms The data were evaluated statistically using Chi-square test (α=0.05).

Results:

Six anerobic bacteria found in teeth and implants sulci were Gram-positive cocci, Gram-negative cocci, Prevotella, Porphyromonas gingivalis, Bacteroid Fragilis and Fusobacterium. Gram-positive cocci and Gram-negative cocci had maximum and minimum percentage frequency in the two groups, respectively. There were no significant differences between the two groups (P value >0.05).

Conclusion:

The present study indicated that microflora in implant sulci is similar to the tooth sulci, when the depth of sulci is normal (<4 mm). As a result, implants’ susceptibility to inflammation is the same as teeth.

Probing and scaling instrumentation on implant abutment surfaces: an in vitro study

PURPOSE

To investigate surface roughness on the apical collar of implant abutments caused by probing and scaling instruments.

MATERIALS AND METHODS

Fourteen transmucosal abutments (BioHorizons, Atlanta, GA) and 4 instruments: UNC-15 metal probe, Periowise plastic probe, McCall SM 17/18 metal scaler, and universal plastic scaler were used to conduct the study. Four abutments were used for nontreated measures, and 10 abutments were treated with the 4 indicated instruments. Surface roughness was assessed with a contact profilometer.

RESULTS

Analysis of variance showed significant differences in surface roughness between the treated and untreated surfaces (P < 0.0001). Add hoc analysis using Tukey-Kramer honestly significant difference test showed no statistical differences between untreated measures and metal probe measures. On the other hand, statistical differences were noted between untreated measures with plastic probe measures (P = 0.05), plastic scaler measures (P = 0.05), and metal scaler measures (P = 0.05). The metal scaler measures were higher than plastic probe measures (P = 0.05) and plastic scaler measures (P = 0.05).

CONCLUSIONS

Probing around implant abutments with a metal probe seems to have no effect on abutment surfaces. In contrast, instrumentation with scalers (metal and plastic) and plastic probe may cause surface roughness.

Biofilm related to dental implants

Oral biofilm-related diseases such as periodontal and peri-implant diseases are unique infections in that they develop from the resident indigenous microflora. As more implants are nowadays being placed, clinicians may encounter more complications. Therefore, understanding the etiology is warranted to establish adequate diagnosis and provide proper treatment. This article focuses on understanding peri-implant microbiology and its roles in peri-implant diseases.

A split-mouth study on microbiological profile in clinical healthy teeth and implants related to key inflammatory mediators

This split-mouth study investigated the correlation of the qualitative and quantitative bacterial composition in dental plaque around clinically healthy periodontal and peri-implant subgingival sites with the levels of selected pro- and anti-inflammatory cytokines and the inflammatory infiltrate in the soft tissue surrounding a healthy dental implant and natural tooth in the same patient. Nine patients, all in good health and non-smokers, were studied. All of the patients were highly motivated in terms of oral hygiene and had healthy natural teeth and at least one healthy implant. After three sessions of professional oral care, clinical parameters were recorded. A sample of subgingival plaque was harvested with a sterile curette from the buccal side of the selected implants and teeth. The plaque samples were cultured to quantify the total microbiota and the number of obligate and facultative bacterial strains. Simultaneously, from the lingual/palatal aspect of the same implants and teeth the keratinized periodontal and peri-implant soft tissues were biopsied for cytokine expression and histomorphometric analysis. The tissue biopsies were halved: the real-time reverse transcriptase-polymerase chain reaction (PCR) was performed to detect active TNF-alpha, IL-1beta, IL-8, and TGF-beta2 and distribution, composition, quantification of inflammation were assessed in parallel. The patients harbored no periodontopathogens and the microbiological composition of the plaque taken from implant sites did not differ from that harvested from teeth. No significant differences were seen between implants and teeth for both proand anti-inflammatory cytokines. Even the histological examination showed no significant epithelial changes, although slight perivascular lymphocytic infiltration was seen in some biopsies.

Effect of surface treatments of titanium on amphotericin B-treated Candida albicans persister cells

Although persister cells in Candida albicans biofilm may contribute to its increased resistance to antifungal drugs, little information is available on the formation of Candida persister cells on titanium surfaces. The effect of different surface treatments of Ti on persister cells was determined in the present study. Titanium discs were surface-treated by three different methods (Group A - polishing, Group B - sandblasting followed by acid-etching, and Group C - sandblasting alone). Persister cells of two C. albicans strains, namely ATCC 90028 and HK30Aa, in biofilm and planktonic states, were measured as the percentage of colony forming units remaining after 24 h incubation with various concentrations of amphotericin B. No persister cells were detected in the planktonic cultures. However, 1.5%, 0.1% and 2.4%C. albicans ATCC 90028 persister cells were detected at an AmB concentration of 64 μg ml(-1) in groups A, B and C, respectively; and 0.3%, 0.2% and 0.6% for groups A, B and C, respectively, for HK30Aa. Group C of C. albicans ATCC 90028 appeared to provide a surface relatively unfavourable for the development of persister cells (P < 0.01). Whether these results may have implications on the clinical performance of titanium implants warrants further investigation.

Fractures related to occlusal overload with single posterior implants: a clinical report

This clinical report describes 2 patient situations in which fractures related to occlusal overload occurred with a single posterior implants. The initial clinical presentation of both patients appeared to be screw loosening, but upon further examination, implant and abutment fractures were identified. Several factors are described that have been implicated in the etiology of implant fractures, including occlusal overload, implant location, inadequate fit of the prosthesis, design of the prosthesis, progressive bone loss, metal fatigue, implant diameter, manufacturing defects, and galvanic activity. This article describes the management of implant and abutment fractures and discusses possible mechanisms of failure for the patient situations presented. Careful treatment planning and execution of implant therapy is necessary to minimize the risk of implant and component fractures.

Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference

The primary function of a dental implant is to act as an abutment for a prosthetic device, similar to a natural tooth root and crown. Any success criteria, therefore, must include first and foremost support of a functional prosthesis. In addition, although clinical criteria for prosthetic success are beyond the scope of this article, patient satisfaction with the esthetic appearance of the implant restoration is necessary in clinical practice. The restoring dentist designs and fabricates a prosthesis similar to one supported by a tooth, and as such often evaluates and treats the dental implant similarly to a natural tooth. Yet, fundamental differences in the support system between these entities should be recognized. The purpose of this article is to use a few indices developed for natural teeth as an index that is specific for endosteal root-form implants. This article is also intended to update and upgrade what is purported to be implant success, implant survival, and implant failure. The Health Scale presented in this article was developed and accepted by the International Congress of Oral Implantologists Consensus Conference for Implant Success in Pisa, Italy, October 2007.

Clinical and microbiological determinants of ailing dental implants

BACKGROUND

The failure of the host tissue to establish or maintain osseointegration around dental implants is due to either occlusal or parafunctional forces, premature loading, ill-directed stress, or microbial infection. The long-term failure rate of dental implants is generally 5-10%. Although a variety of etiologies of early peri-implant bone loss (from implant placement to 1-year post-loading) have been proposed, factors associated with late implant failures are less well understood but are probably related to both the peri-implant microbial environment and host factors. Discriminating between causes of implant failure is of importance for instituting a successful implant therapy.

PURPOSE

The objective of this cross-sectional split-mouth study was to identify clinical, radiographic, and bacterial characteristics of peri-implant disease sites.

MATERIALS AND METHODS

Fifteen patients with bilateral implants (Brånemark, Nobel Biocare AB, Göteborg, Sweden; and 3i implant systems, Implant Innovations Inc., Palm Beach Gardens, FL, USA) participated in the study. Sites with peri-implant (radiographic bone loss beyond the third implant thread) and peri-implant healthy tissues (radiographic bone level above the first implant thread) were identified in periapical radiographs using a long-cone paralleling projection technique. Microbiological identification was carried out using established anaerobic culture techniques. A descriptive statistics based on means and standard deviations was reported.

RESULTS

Peri-implant bone loss was associated with the absence of radiographic crestal lamina dura, peri-implant pocket depth, pain on chewing, and the submucosal presence of the putative periodontopathogens Tannerella forsythia, Campylobacter species, and Peptostreptococcus micros. Pain was associated with P. micros, Fusobacterium species, and Eubacterium species.

DISCUSSION AND CONCLUSION

The absence of radiographic crestal lamina dura and the presence of suspected major periodontal pathogens seem to be associated to peri-implantitis.

Dental implants: Maintenance, care and treatment of peri-implant infection

Osseointegration is becoming increasingly routine in the rehabilitation of partially or fully edentulous patients. However, the surrounding tissues may be subject to inflammatory conditions similar to periodontal disease and so require maintenance. This article discusses the background, aetiology, diagnosis of peri-implant diseases, and the maintenance, care and treatment of peri-implant infection in osseointegrated implants. Three case studies are presented to illustrate points in the care of implants.

A Clinical, Radiographic, and Microbiologic Comparison of Astra Tech and Brånemark Single Tooth Implants

BACKGROUND

The soft tissues around single tooth implants differ fundamentally from the gingiva around natural teeth. There are very limited data comparing soft tissues around different implant systems.

AIM

To assess whether the design characteristics of dental implants, particularly the implant-abutment junction, may affect the dimensions and health of the peri-implant soft tissues and radiographic bone levels.

SUBJECTS AND METHOD

Fifteen Astra Tech and 15 Brånemark single tooth implants that had been in function for a minimum of 2 years in 30 partially dentate subjects were examined for plaque accumulation, probing depth, and bleeding on probing and compared to contralateral healthy teeth. Standardized radiographs were taken to measure the most coronal bone to implant contact on the mesial and distal surfaces. In addition, samples of subgingival plaque were taken on paper points and examined by darkfield microscopy.

RESULTS

Significantly higher mean probing depths (p < .001) and higher mean percentage of spirochetes (p = .003) were found at implants compared to teeth. In this sample, the Brånemark implants had significantly higher probing depths than the Astra Tech implants (median and interquartile range: Astra Tech 2.7 mm [2-3], Brånemark 3.3 mm [3-3.7] p = .026) and the most coronal bone to implant contact was closer to the implant-abutment junction in the Astra Tech implants (Astra Tech 0.6 mm [0.2-0.9], Brånemark 1.6 mm [1.4-2.0]. p < .001).

CONCLUSION

Although there were statistically significant differences between the two implant systems, the clinical differences were small and probably reflect differences in the biologic width in relation to the location and design of the implant-abutment junction.

Influence of an Erbium, Chromium-Doped Yttrium, Scandium, Gallium, and Garnet (Er,Cr:YSGG) Laser on the Reestablishment of the Biocompatibility of Contaminated Titanium Implant Surfaces

BACKGROUND

The aim of the present study was to evaluate the influence of an erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG laser [ERCL]) on 1) the surface structure and biocompatibility of titanium implants and 2) the removal of plaque biofilms and reestablishment of the biocompatibility of contaminated titanium surfaces.

METHODS

Intraoral splints were used to collect an in vivo supragingival biofilm on sand-blasted and acid-etched titanium disks for 24 hours. ERCL was used at an energy output of 0.5, 1.0, 1.5, 2.0, and 2.5 W for the irradiation of 1) non-contaminated (20 and 25 Hz) and 2) plaque-contaminated (25 Hz) titanium disks. Unworn and untreated non-irradiated, sterile titanium disks served as untreated controls (UC). Specimens were incubated with SaOs-2 osteoblasts for 6 days. Treatment time, residual plaque biofilm (RPB) areas (%), mitochondrial cell activity (MA) (counts per second), and cell morphology/surface changes (scanning electron microscopy [SEM]) were assessed.

RESULTS

1) ERCL using either 0.5, 1.0, 1.5, 2.0, or 2.5 W at both 20 and 25 Hz resulted in comparable mean MA values as measured in the UC group. A monolayer of flattened SaOs-2 cells showing complete cytoplasmatic extensions and lamellopodia was observed in both ERCL and UC groups. 2) Mean RPB areas decreased significantly with increasing energy settings (53.8 +/- 2.2 at 0.5 W to 9.8 +/- 6.2 at 2.5 W). However, mean MA values were significantly higher in the UC group.

CONCLUSION

Within the limits of the present study, it was concluded that even though ERCL exhibited a high efficiency to remove plaque biofilms in an energy-dependent manner, it failed to reestablish the biocompatibility of contaminated titanium surfaces.

Interaction of chlorhexidine with smooth and rough types of titanium surfaces

BACKGROUND

Chlorhexidine (CHX) digluconate exerts plaque inhibitory efficacy in the natural dentition environment due to a superior degree of persistence at the tooth surface. The purpose of the present study was to assess the interaction of CHX with titanium surfaces to estimate its antiplaque potential in the peri-implant environment.

METHODS

Saliva-coated machined smooth (S) and sand-blasted acid-etched rough (R) titanium disks were soaked in either 0.1% or 0.2% CHX solution. After 24 hours, CHX amounts that were adsorbed, washed out, and desorbed from the titanium surfaces were determined spectrophotometrically at 230 nm. The antibacterial activity of CHX-treated titanium disks was assessed by measuring bacterial inhibition zones on Streptococcus mutans lawns.

RESULTS

Titanium disks adsorbed 3% to 8% of the available CHX, which was significantly higher with 0.2% CHX (P<0.001) than with 0.1% CHX and two-fold higher on the R titanium disks compared to S titanium surface (P<0.001). After rinsing with water, 2.2% of the adsorbed CHX was washed out. Over 24 hours, S- and R-type disks released 1.1% and 0.6% of the adsorbed agent, respectively. Larger bacterial inhibition zones were obtained with 0.2% CHX and in R disks compared to S disks.

CONCLUSIONS

CHX displayed persistence at the titanium surface. The adsorption level and bacterial growth inhibition were affected by CHX concentration and titanium surface characteristics, with higher levels of adsorption and antibacterial activity with 0.2% CHX and rough titanium surface. The slow CHX release rate suggests persistence of this agent at the titanium-pellicle surface, which can provide a long-term antiplaque effect.

Bacterial Plaque Colonization Around Dental Implant Surfaces

PURPOSE

To examine the distribution of bacteria into the internal and external surfaces of failed implants using histologic analysis.

MATERIALS AND METHODS

There were 10 failed pure titanium and 5 failed hydroxyapatite-coated titanium implants consecutively removed various years after their placement. Criteria for fixture removal were peri-implant radiolucency and clinical mobility. The mobile fixtures were retrieved with the patients under local anesthesia. Fixtures were removed maintaining the abutments with the aim to observe the bacterial infiltration at the level of abutment/implant interface and on the implant surface.

RESULTS

A thin radiolucent space was always present around all the failed implants. The abutments screws were tightly secured in all clinical cases. The bacterial cells were composed of cocci and filaments, which were adherent to the implant surface with an orientation perpendicular to the long axis of the implant. All the specimens included in this study showed bacteria at the level of implant/abutment interface.

CONCLUSIONS

Histologic analysis at the level of abutment/implant interface in 2-stage implants identified heavy bacterial colonization. These findings appear to support those studies showing bacteria penetration at the level of the micro-gap, which can legitimate the hypothesis that the micro-gap at the bone level could present a risk for bone loss caused by bacterial colonization.

Influence of plaque biofilm removal on reestablishment of the biocompatibility of contaminated titanium surfaces

The aim of the present study was to evaluate the influence of plaque biofilm removal on the mitochondrial activity of human SaOs-2 osteoblasts grown on titanium surfaces. Volunteers wore acrylic splints with structured titanium discs for 72 h to build up plaque biofilms (n = 30). Specimens were randomly instrumented using either (1) an ultrasonic system at two power settings (EMS1, EMS2) + chlorhexidine (CHX), or (2) plastic curettes + CHX. Untreated (NC, n = 10) and sterile (C, n = 10) titanium discs served as controls. Specimens were incubated with SaOs-2 cells for 6 days. Treatment time (T), residual plaque biofilm (RPB)/clean implant surface areas (%), mitochondrial cell activity (MA) (counts/second), and cell morphology (SEM) were assessed. Statistical analysis revealed the following mean scores (+/-SD): RPB areas: P (58.5 +/- 4.9) > EMS1 (38.4 +/- 4.1) > EMS2 (28.3 +/- 2.0); T: PC (292 +/- 30) = EMS1 (244 +/- 24) > EMS2 (199 +/- 25); MA: C (1.544.661 +/- 203.442) > PC (597.559 +/- 566.984) = EMS2 (389.875 +/- 409.300) = EMS1 (356.653 +/- 293.863; n.s.) > NC (138.676 +/- 86.666). In NC and PC groups, cells were predominantly rounded in shape. However, in the EMS groups, some cells had started to spread, showing complete cytoplasmatic extensions of the cell body on the titanium surface. A monolayer of flattened cells was generally observed in the C group. Within the limits of the present study, it was concluded that MA seemed to be impaired by the presence of RPB areas. However, its removal alone might not be the crucial step in the reestablishment of the biocompatibility of titanium surfaces.

Influence of different treatment approaches on the removal of early plaque biofilms and the viability of SAOS2 osteoblasts grown on titanium implants

The aim of the present study was to evaluate the influence of different treatment approaches on: (1) the removal of early plaque biofilms grown on titanium implants, and (2) the biocompatibility of the instrumented implant surfaces. Five volunteers wore acrylic splints with sand-blasted and acid-etched titanium discs for 24 h to build up supragingival plaque. A total of 80 specimens were randomly assigned to the following groups: (1) an Er:YAG laser (100 mJ/pulse, 10 Hz) (Y), (2) an ultrasonic system (U), (3) plastic curettes and rinsing with chlorhexidine digluconate (P), or (4) unworn titanium discs (C). Autoclaved specimens were incubated with SAOS2 cells for three days. The following parameters were measured: treatment time (T), residual plaque biofilm (RPB) and clean implant surface (CIS) areas (%), and mitochondrial cell activity (MA) (counts/s). Statistical analysis within and between groups revealed the following mean scores (+/-SD): RPB areas: P (61.1+/-11.4)>U (36.8+/-4.5)>Y (5.8+/-5.1); CIS areas: Y (94.2+/-5.1)>U (63.2+/-4.5)>P (38.9+/-11.2); T: Y (5.6+/-1.2)>U (2.4+/-0.5)>P (2.3+/-0.5); MA: C (1.528.636+/-188.371)>U (831.594+/-370.228)>Y (678.250+/-367.902)>P (144.105+/-120.961). Within the limits of the present study, it may be concluded that Y seems to be most suitable for the removal of supragingival early plaque biofilms grown on SLA titanium implants, and (2) all treatment procedures failed to restore the biocompatibility of previously-contaminated SLA titanium surfaces.

Histological evidence of osseointegration in human retrieved fractured hydroxyapatite-coated screw-type implants: a case report

Histological evidence of clinically successful dental implants is very rare. This case report presents histological evidence of osseointegration in human implants retrieved because of fractures at the connected portion between the abutments and fixtures due to a car accident. The duration of functional loading of the implants was 18 months. Two hydroxyapatite (HA)-coated screw-type implants were removed with part of the healthy bone from the mandibular left molar region. A block was prepared using cutting and grinding equipment to obtain a central section approximately 50 microm thick, which was stained with basic fuchsin and methylene blue. Histological examination revealed that the bone was dense and in close relation with the HA coating of the implants. The interspaces of each thread of the implant were filled with mineralized bone. Peri-implant soft tissue was not observed in the section. A high degree of osseointegration was noted, with a bone-to-implant contact of 87.5% (implant corresponding to tooth 36) and 97.4% (implant corresponding to tooth 37). The connection between the 30 and 50 microm HA coating and the metal was uniformly tight and constant. In conclusion, the histological evidence showed a high degree of osseointegration in two HA-coated screw-type dental implants retrieved after functional loading for 18 months.

Correlation of peri-implant health and myeloperoxidase levels: a cross-sectional clinical study

OBJECTIVES

At present, there are no diagnostic tools that permit early detection of peri-implantitis. The purpose of this cross-sectional study was to evaluate the correlation of myeloperoxidase (MPO) levels with traditional periodontal clinical parameters around dental implants including peri-implant pocket probing depth (PPD), gingival index (GI) and bleeding on probing (BOP), since MPO has been associated with destruction of periodontal tissues.

MATERIAL AND METHODS

Twenty-four healthy adult volunteers (9 men and 15 women) with 64 Ankylos Biofunctional implants (DentsplyFriadent, Mannheim, Germany) were recruited from Tallinn Dental Clinic. Biochemical and clinical parameters evaluated were the following ones: the level of MPO in the peri-implant sulcus fluid (PISF) (an analog for gingival crevicular fluid in natural teeth), PPD (mm), GI (0,1,2 or 3), and BOP (0 or 1).

RESULTS AND CONCLUSION

In comparison to the clinically healthy implants, total amounts of MPO were significantly higher in PISF collected around implants with inflammatory lesions. In addition, the levels of MPO were correlated with the clinical parameters. The results confirm the similarity of the inflammatory response of tissues surrounding implants and natural teeth, and suggest that MPO could be promising marker of inflammation around dental implants.

Does excessive occlusal load affect osseointegration? An experimental study in the dog

AIM

The purpose of this study was to evaluate the effect of excessive occlusal load following placement of titanium implants in the presence of healthy peri-implant mucosal tissues.

MATERIALS AND METHODS

Mandibular bilateral recipient sites in six Labrador dogs were established by extracting premolars and molars. After 3 months, two TPS (titanium plasma sprayed) implants and two SLA (sandblasted, large grit, acid etched) implants were placed on each side of the mandible in each dog. Three implants were lost in the initial healing phase, leaving 45 implants for evaluation. Following 6 months of healing, gold crowns were placed on implants on the test side of the mandible. The crowns were in supra-occlusal contact with the opposing teeth in order to create excessive occlusal load. Implants on the control side were not loaded. Plaque control was performed throughout the experimental period. Clinical measurements and standardised radiographs were obtained at baseline and 1, 3 and 8 months after loading. At 8 months, the dogs were killed and histologic analyses were performed.

RESULTS

At 8 months, all implants were osseointegrated. The mean probing depth was 2.5+/-0.3 and 2.6+/-0.3 mm at unloaded and loaded implants, respectively. Radiographically, the mean distance from the implant shoulder to the marginal bone level was 3.6+/-0.4 mm in the control group and 3.7+/-0.2 mm in the test group. Control and test groups were compared using paired non-parametric analyses. There were no statistically significant changes for any of the parameters from baseline to 8 months in the loaded and unloaded implants. Histologic evaluation showed a mean mineralised bone-to-implant contact of 73% in the control implants and 74% in the test implants, with no statistically significant difference between test and control implants.

CONCLUSION

In the presence of peri-implant mucosal health, a period of 8 months of excessive occlusal load on titanium implants did not result in loss of osseointegration or marginal bone loss when compared with non-loaded implants.

Microbiologic Diagnostics at Titanium Implants

BACKGROUND

The microbiota found at periimplant lesions have been shown to contain putative periodontal pathogens as well as opportunistic species such as Staphylococcus spp, enterics, and Candida spp. Therefore, a microbiologic diagnosis may be of value as guidance before treatment of such lesions.

PURPOSE

The aim of this study was to evaluate the prevalence of some putative pathogens associated with long-term followed-up cases using two different microbiologic procedures.

MATERIALS AND METHODS

Fifteen subjects contributed with plaque samples from teeth and implants; these were analyzed with respect to 18 putative periimplant pathogens using cultural methods and a deoxyribonucleic acid DNA-DNA hybridization technique.

RESULTS

The number of individuals positive for the analyzed pathogens was similar in samples taken from teeth and implants when analyzed with the DNA-DNA hybridization technique. When comparing detection frequency by culture procedure and by "checkerboard" technique at implants, the number of individuals positive for these species was lower with the traditional culture technique than with the checkerboard analyses. Using a higher cutoff point (> or = 4) with the checkerboard technique, the number of positive individuals was generally lower than that found with the culture technique. When comparing the techniques on an implant site level, the prevalence obtained by culture was lower for all analyzed species. If the specific species were present in the samples analyzed by the checkerboard technique, they were present only in every second sample analyzed with the culture technique. The high specificity values showed that if the checkerboard technique did not detect any Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, or Fusobacterium nucleatum, the bacteria were also undetectable by the culture technique. The two methods therefore did not overlap but did supplement each other.

CONCLUSIONS

Based on the current results it is recommended that the technique used when analyzing microbiota around titanium implants should be a combination of the two protocols mentioned as they seem to give the most comprehensive outcome when used together.

The Use of Implantoplasty and Guided Bone Regeneration in the Treatment of Peri-implantitis: Two Case Reports

A variety of treatment modalities have been proposed for the management of peri-implantitis. These are mostly based on empiric experience and use the systemic administration of an antibiotic in conjunction with surgical intervention. To ensure decontamination of the affected implant surface(s), chemical and/or mechanical debridement is used. For textured implant surfaces, detoxification using implantoplasty could also give favorable results when used as part of the procedure. Two cases are reported in which implants developed localized peri-implantitis lesions. Implantoplasty followed by topical tetracycline decontamination was used in conjunction with guided bone regeneration. In both cases, the procedures were effective in arresting disease and regenerating lost bone. These results suggest that the technique holds promise and should be investigated further.

Periimplant probing: positives and negatives

Periodontium in normal dentition is not as it is surrounding an implant area. Thus, periodontal probing with normal dentition is not similar to periimplant probing. The periimplant probing protocol should be different from periodontal probing because of inherent anatomical differences. The aim of this paper is to review the topics related to periimplant probing and to draw inferences to develop a periimplant probing protocol.