Clinical and microbiological status of osseointegrated implants

Risk Analysis of Nonunion After First Metatarsophalangeal Joint Arthrodesis

Objective: The standard therapy for a symptomatic hallux rigidus is still the arthrodesis of the first metatarsophalangeal (MTP) joint. A nonunion of the arthrodesis is a possible postoperative complication. This study aimed to evaluate the incidence of nonunion associated with first MTP joint arthrodesis and identify risk factors influencing this. Methods: This retrospective study included 197 patients who were treated with an isolated first MTP joint arthrodesis. The severity of MTP-related osteoarthritis was assessed clinically and radiologically prior to surgery according to the Waizy classification. Patient characteristics and radiological parameters were evaluated postoperatively. Results: A full clinical and radiological data set was collected from 153 out of 197 patients. We identified 14 cases of nonunion and found that nonunion was associated with higher incidence of male gender (P = .29), comorbidity (P = .035), higher grade of osteoarthritis (P = .01), and increased postoperative great toe dorsiflexion (P = .022). Conclusions: Arthrodesis of the first MTP joint is a safe operative treatment, as demonstrated by a nonunion rate of 9.2%. Negative influencing factors were the presence of preexisting diseases, higher grades of osteoarthritis, and a relative increased dorsiflexion position of the great toe after surgery. These factors should be considered during pre-, intra-, and postoperative planning.Levels of Evidence: Therapeutic, Level IV: Retrospective.

Microbial Etiology and Antimicrobial Therapy of Peri-implantitis: A Comprehensive Review

Introduction:

Implants have turned out to be a well-established therapy in dental practice for the replacement of missing teeth and restoration of function.

Peri-implant disease denotes the inflammatory condition of surrounding soft and hard tissues.

Two terminologies are covered under the impression of peri-implant pathology; peri-implantitis and mucositis. Peri-implant mucositis is a reversible inflammatory process limited to soft tissues around an implant. Peri-implantitis is an inflammatory condition of hard and soft tissue around the dental implant.

Microbial Etiology:

Bacterial infections are the most common cause of peri-implantitis. It is a variable poly-microbial infection, although generally dominated by Gram-negative anaerobic bacteria Anti-infective therapy should be included in the treatment regime, while treating the peri-implant disease. Antimicrobial therapy includes local debridement, antibiotic therapy and surface decontamination of the implant.

Conclusion:

The current article gives a detailed overview of microbial etiology, antimicrobial therapy and its limitations for the treatment of peri-implant Pathology.

Surface property alterations and osteoblast attachment to contaminated titanium surfaces after different surface treatments: An in vitro study

BACKGROUND

Studies have reported a high prevalence of peri-implantitis. The etiology of peri-implantitis remains unclear and no available treatments result in total resolution of established peri-implantitis.

PURPOSE

To investigate the factors that interfere with osteoblast adhesion to contaminated titanium surfaces after different surface treatments.

MATERIALS AND METHODS

Grade 4 titanium discs were randomly divided into 5 groups and each group was divided into 2 subgroups, with one contaminated with Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), and the other contaminated with Porphyromonas gingivalis (P. gingivalis). Group 1 did not receive bacterial inoculation or surface debridement and served as a control. Group 2 received A. actinomycetemcomitans or P. gingivalis inoculation, separately. Group 3 received bacterial inoculation and titanium curette debridement, followed by normal saline irrigation. Group 4 received bacterial inoculation, curette debridement, normal saline irrigation, and ultrasonication. Group 5 received bacterial inoculation, curette debridement, normal saline irrigation, and placement in 0.12% chlorhexidine. After various surface treatments, the surface roughness and hydrophilicity of the titanium surface were measured, the number of adhered osteoblast cells was calculated, and the amount of residual lipopolysaccharide (LPS) was quantified.

RESULTS

A. actinomycetemcomitans and P. gingivalis biofilms noticeably reduced surface hydrophilicity. Groups 3-5 showed decreased hydrophilicity and fewer adhered osteoblast cells compared with the control group. Although ultrasonication was more effective in removing LPS than curette debridement and chlorhexidine, cell adhesion was not as high as with clean titanium discs.

CONCLUSIONS

The non-surgical treatment used in this study was not effective in removing LPS from titanium surfaces and increasing osteoblast adhesion. A more effective method to remove LPS completely is required to enhance the treatment outcome of peri-implantitis.

Comprehensive Treatment of Severe Periodontal and Periimplant Bone Destruction Caused by Iatrogenic Factors

Dental implant success requires placement after periodontal therapy, with adequate bone volume, plaque control, primary stability, control of risk factors, and use of well-designed prostheses. This report describes the surgical and prosthetic management of a patient with severe iatrogenic periodontal/periimplant bone destruction. Methods. A 55-year-old female smoker with fixed partial dentures (FPDs) supported on teeth and implants presented with oral pain, swelling, bleeding, and a 10-year history of multiple implant placements and implants/prosthesis failures/replacements. Radiographs showed severe bone loss, subgingival caries, and periapical lesions. All implants and teeth were removed except implants #4 and #10 which served to retain an interim maxillary restoration. Bone defects were covered with nonresorbable dPTFE membranes. In the mandible, three new implants were placed and loaded immediately with a bar-retained temporary denture. Results. Seven months postoperatively, the bone defects were regenerated, and three additional mandibular implants were placed. All mandibular implants were splinted and loaded with a removable overdenture. Conclusions. In this case, periimplant infection and tissue destruction resulted from the lack of periodontal treatment/maintenance and failure to use evidence-based surgical and loading protocols. Combination therapy resolved the disease and the patient's severe discomfort while providing immediate function and an aesthetic solution.

Antibacterial and bioactive coatings on titanium implant surfaces

Various surface modifications have been tried for enhancing osseointegration of the dental implants like mechanical and/or chemical treatments and deposition of calcium phosphate coatings. The objective of this research was to develop calcium-phosphate based thin coatings with antibacterial and bioactive properties for potential application in dental implants. Titanium (Ti) discs were immersed in different calcifying solutions: CaP (positive control), F-CaP, Zn-CaP, and FZn-CaP and incubated for 24 h. Negative control was uncoated Ti discs. Coated surfaces were characterized using X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Antibacterial properties were tested using Porphyromonas gingivalis because of its strong association with periodontal and peri-implant infections. Bacterial adhesion and colonization were studied at different timepoints. The coated surfaces had compositional characteristics similar to that of bone mineral and they inhibited the growth, colonization and adherence of P. gingivalis, resulted in reduced thickness of biofilms and bacterial inhibition in the culture medium as compared to the positive and negative controls (p < 0.05). There was no significant difference between the experimental groups (p > 0.05). It has been previously demonstrated that these coatings have excellent in vitro bioactivity (formed carbonate hydroxyapatite when immersed in a simulated body fluid). Such coatings can enhance osseointegration and prevent infection in implants, thereby improving the success rates of implants. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2218-2227, 2017.

A clinico radiographic study of immediate loading implants in rehabilitation of mandibular ridges

BACKGROUND

Numerous studies regarding the immediate loading of splinted implants retaining/supporting mandibular dentures have reported promising results, but studies comparing splinted and unsplinted attachments for supporting overdentures with immediate loading are limited. Scientific literature is sparse comparing various attachment systems and patient satisfaction in response to immediately loaded implant supported overdentures.

METHODS

A total of 30 completely edentulous patients male or female, in the age group of 54-78 years (mean age 65 years), wearing conventional complete dentures were selected and randomly divided in to two groups. A total of 60 implants were placed in the interforaminal area of the mental symphysis (two implants per patients) in 30 patients. Two types of attachment systems namely Ball for group-A and Bar for group-B were used and immediate loading done. Implants were evaluated clinically and radiographically at baseline, 1 month, 3 months, 6 months and 9 months. All clinical and radiographic parameters were subjected to statistical analysis.

RESULT

The implant survival rate for group-A (ball attachment) was 93.3% and implant survival rate for group-B (bar attachment) was 93.3%. The overall implant survival rate was not dependent on the attachment system. There was no significant difference in the crestal bone loss in mesial, and distal side in implants with respect to ball and bar attachment for different period of observation (F = 0.25; P = 0.910; F = 0.07; P = 0.992 respectively).

CONCLUSION

Overdenture supported by two implants should be the minimum gold standard in the rehabilitation of completely edentulous patients.

Tetracycline tethered to titanium inhibits colonization by Gram-negative bacteria

As peri-prosthetic infection is one of the most devastating complications associated with implant placement, we have reasoned that such infection can be largely subverted by development of antibacterial implants. Our previous work demonstrated that covalent coupling of vancomycin to titanium alloy prevented colonization by the Gram-positive pathogens, Staphylococcus aureus and Staphylococcus epidermidis. Some orthopedic devices, including permanent prosthesis anchors, and most dental implants are transcutaneous or transmucosal and can be prone to colonization by Gram-negative pathogens. We report here the successful covalent coupling of the broad-spectrum antibiotic, tetracycline (TET), to titanium surfaces (Ti-TET) to retard Gram-negative colonization. Synthetic progress was followed by changes in water contact angle, while the presence of TET was confirmed by immunofluorescence. Ti-TET actively prevented colonization in the presence of bathing Escherichia coli, both by fluorescence microscopy and direct counting. Finally, the Ti-TET surface supported osteoblastic cell adhesion and proliferation over a 72-h period. Thus, this new surface offers a powerful means to protect transcutaneous implants from adhesion of Gram-negative pathogens, decreasing the need for replacement of this hardware.

Effects of dextrose and lipopolysaccharide on the corrosion behavior of a Ti-6Al-4V alloy with a smooth surface or treated with double-acid-etching

Diabetes and infections are associated with a high risk of implant failure. However, the effects of such conditions on the electrochemical stability of titanium materials remain unclear. This study evaluated the corrosion behavior of a Ti-6Al-4V alloy, with a smooth surface or conditioned by double-acid-etching, in simulated body fluid with different concentrations of dextrose and lipopolysaccharide. For the electrochemical assay, the open-circuit-potential, electrochemical impedance spectroscopy, and potentiodynamic test were used. The disc surfaces were characterized by scanning electron microscopy and atomic force microscopy. Their surface roughness and Vickers microhardness were also tested. The quantitative data were analyzed by Pearson's correlation and independent t-tests (α = 0.05). In the corrosion parameters, there was a strong lipopolysaccharide correlation with the Ipass (passivation current density), Cdl (double-layer capacitance), and Rp (polarization resistance) values (p<0.05) for the Ti-6Al-4V alloy with surface treatment by double-acid-etching. The combination of dextrose and lipopolysaccharide was correlated with the Icorr (corrosion current density) and Ipass (p<0.05). The acid-treated groups showed a significant increase in Cdl values and reduced Rp values (p<0.05, t-test). According to the topography, there was an increase in surface roughness (R2 = 0.726, p<0.0001 for the smooth surface; R2 = 0.405, p = 0.036 for the double-acid-etching-treated surface). The microhardness of the smooth Ti-6Al-4V alloy decreased (p<0.05) and that of the treated Ti-6Al-4V alloy increased (p<0.0001). Atomic force microscopy showed changes in the microstructure of the Ti-6Al-4V alloy by increasing the surface thickness mainly in the group associated with dextrose and lipopolysaccharide. The combination of dextrose and lipopolysaccharide affected the corrosion behavior of the Ti-6Al-4V alloy surface treated with double-acid-etching. However, no dose-response corrosion behavior could be observed. These results suggest a greater susceptibility to corrosion of titanium implants in diabetic patients with associated infections.

Ailing and failing oral implants: initial therapy and surgical management

The distinction between ailing and failing implants is clinically important. Changes in the peri-implant soft or hard tissues will indicate whether the implant is ailing, failing, or has failed. This article discusses these clinical situations and provides an overview and description of peri-implant diseases and their treatment alternatives.

Hierarchical decisions on teeth vs. implants in the periodontitis-susceptible patient: the modern dilemma

It is estimated that advanced periodontitis typically affects about 10% of most adult populations studied. These individuals can be considered highly susceptible to periodontitis and often present difficulties for clinicians in therapeutic decision making, especially when dental implants are involved. Poor plaque control and smoking are well established risk factors for periodontitis, as well as for peri-implant disease. Long-term follow-up studies have clearly demonstrated that treatment of periodontal disease, even if advanced, can be successful in arresting disease progression and preventing (or at least significantly delaying) tooth loss. With the increasing development of implant dentistry, traditional well documented and evidence-based therapies to treat periodontal diseases may sometimes not be used to their full potential. Instead, there appears to be an increasing tendency to extract periodontally compromised teeth and replace them with implants, as if implants can solve the problem. However, peri-implant diseases are prevalent, affecting between 28% and 56% of people with implants, and (at the implant level) 12-43% of implants. A history of periodontal disease, smoking and poor oral hygiene are all risk factors for developing peri-implantitis. Unlike periodontitis, there are currently no predictable means for treating peri-implantitis, although resective surgery seems to be the most effective technique. Consequently, if implant treatment is considered in patients who are susceptible to periodontitis, it should be preceded by appropriate and adequate periodontal treatment or re-treatment to control the condition, and should be followed by a stringent supportive maintenance program to prevent the development of peri-implant disease. The decision whether implant treatment should be performed should be based on an assessment of the patient's risk profile at the subject level, as well as at the site level.

Influence of etiologic factors in peri-implantitis: literature review and case report

Peri-implantitis is a pathology that has been described in many clinical studies and case reports. However, it is still not clear how the roles of its etiologic agents work. This article is based on a review of the literature and a case report. It aims to offer data related to the factors that cause this pathology, and to analyze how these factors interact, leading to the contamination of the peri-implant tissue.

Biomaterial and antibiotic strategies for peri-implantitis: a review

Dental implants have 89% plus survival rates at 10-15 years, but peri-implantitis or dental implant infections may be as high as 14%. Peri-implantitis can limit clinical success and impose health and financial burdens to patients and health providers. The pathogenic species associated with periodontitis (e.g., Fusobacterium ssp, A. actinomycetemcomitans, P. gingivalis) are also associated with peri-implantitis. Incidence of peri-implantitis is highest within the first 12 months after implantation, and is higher in patients who smoke or have poor oral health as well as with calcium-phosphate-coated or surface-roughened implants. Biomaterial therapies using fibers, gels, and beads to deliver antibiotics have been used in the treatment of Peri-implantitis though clinical efficacy is not well documented. Guided tissue regeneration membranes (e.g., collagen, poly-lactic/glycolic acid, chitosan, ePTFE) loaded with antimicrobials have shown success in reosseointegrating infected implants in animal models but have not been proven in humans. Experimental approaches include the development of anti-bioadhesion coatings, coating surfaces with antimicrobial agents (e.g., vancomycin, Ag, Zn) or antimicrobial releasing coatings (e.g., calcium phosphate, polylactic acid, chitosan). Future strategies include the development of surfaces that become antibacterial in response to infection, and improvements in the permucosal seal. Research is still needed to identify strategies to prevent bacterial attachment and enhance normal cell/tissue attachment to implant surfaces.

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.

Analysis of early biofilm formation on oral implants in man

Biofilm formation on oral implants can cause inflammation of peri-implant tissues, which endangers the long-term success of osseointegrated implants. It has been reported previously that implants revealing signs of peri-implantitis contain subgingival microbiota similar to those of natural teeth with periodontitis. The purpose of the first part of this study was an atraumatic, quantitative investigation of biofilm formation on oral implant abutments; the objective of the second part was to investigate whether Haemophilus actinomycetemcomitans and Porphyromonas gingivalis were present in the crevicular fluid around oral implants. Biofilm formation on 14 healing abutments, inserted for 14 days in 10 patients, was analysed quantitatively by use of secondary-electron and Rutherford-backscattering-detection methods. A 16S rRNA-based polymerase chain reaction detection method was used to detect the presence of H. actinomycetemcomitans and P. gingivalis in the crevicular fluid. For this investigation, samples of sulcus fluid were collected with sterile paper points at four measurement points per abutment. The difference between biofilm coverage of supragingival surfaces (17.5 +/- 18.3%) and subgingival surfaces (0.8 +/- 1.0%) was statistically significant (P < 0.05). By use of universal primers, bacteria were found in all the samples taken, although the two periodontal pathogens were not found in any of the samples. The absence of periodontal pathogens from the sulcus fluid during initial bacterial colonization, despite massive supragingival biofilm formation, substantiates the assumption that cellular adherence of peri-implant tissue by means of hemidesmosoma, actin filaments and microvilli reduces the risk of formation of anaerobic subgingival pockets.

Decontamination of rough titanium surfaces with diode lasers: microbiological findings on in vivo grown biofilms

OBJECTIVES

The bactericidal efficacy of diode lasers has already been demonstrated in vitro. We investigated the reduction of aerobe bacteria - colonizing rough titanium samples in biofilms intraorally grown - by diode lasers of different wave lengths.

MATERIAL AND METHODS

Twenty-two volunteers participated in the trial. They were fitted for 10 days with custom-made intraoral plastic splints carrying titanium sleeves. A part of the sleeves was then irradiated with diode lasers in different modes. The other part remained non-irradiated and served as control. Directly after irradiation, the sleeves were swabbed and the gained bacteria were first examined microscopically and then were cultured under aerobic conditions.

RESULTS

The bacteria in the controls and in the treated samples were quantified. A comparison with the controls revealed a marked overall reduction of bacterial colonization in all irradiated sleeves. Continuous irradiation for 20 s reduced bacteria counts by 99.67% at 810 nm and 99.58% at 980 nm. Repeating the 20 s exposure five times reduced counts by 99.98% at 810 nm and by 99.39% at 980 nm. A 98.86% reduction was seen after irradiation in pulsed mode. A further analysis in respect of different isolated bacteria revealed that the streptococci group was reduced by 99.29-99.99%, while the staphylococci group was reduced to a lesser extent in the range 94.67-99.99%.

CONCLUSION

The results are of clinical relevance. In comparison with the mean bacterial counts of the untreated samples, all irradiation programs studied in this investigation reduced mean bacterial colonization in a biofilm on intraoral rough titanium surfaces by more than 98%. The actual extent of reduction was dependent on the bacteria species as well as on the irradiation mode.

Nine- to fourteen-year follow-up of implant treatment. Part II: presence of peri-implant lesions

OBJECTIVES

The aim of this study was to analyse the proportions of peri-implant lesions at implants after 9-14 years of function.

MATERIAL AND METHODS

Two hundred and ninety-four patients underwent implant therapy during the years 1988-1992 in Kristianstad County. These individuals were recalled to the speciality clinic 1 and 5 years after placement of the suprastructure. Between 2000 and 2002, 218 patients with 999 implants were examined clinically and radiographically.

RESULTS

Forty-eight per cent of the implants had probing depth > or =4 mm and bleeding on probing (peri-implant mucositis). In 20.4% of the implants, the bone level was located 3.1 mm apical to the implant shoulder. Progressive bone loss (> or =1.8 mm) during the observation period was found in 7.7% of the implants. Peri-implantitis defined as bone loss > or =1.8 mm compared with 1-year data (the apical border of the bony defect located at or apical to the third thread, i.e. a minimum of 3.1 mm apical to the implant shoulder), combined with bleeding on probing and or pus, were diagnosed among 16% of the patients and 6.6% of the implants.

CONCLUSION

After 10 years in use without systematic supportive treatment, peri-implant lesions is a common clinical entity adjacent to titanium implants.

Nine- to fourteen-year follow-up of implant treatment. Part I: implant loss and associations to various factors

OBJECTIVES

The aim of the present study was to evaluate the long-term result of implant therapy, using implant loss as outcome variable.

MATERIAL AND METHOD

Two hundred and ninty-four patients had received implant therapy (Brånemark System) during the years of 1988-1992 in Kristianstad County, Sweden. The patients were recalled to the speciality clinic 1 and 5 years after placement of the suprastructure. Between 2000 and 2002, 9-14 years after implant placements, the patients were again called in for a complete clinical and radiographic examination.

RESULTS

Two hundred and eighteen patients treated with 1057 implants were examined. Twenty-two patients had lost 46 implants and 12 implants were considered "sleeping implants". The overall survival rate was 95.7%. Implant loss appeared in a cluster in a few patients and early failures were most common. Eight patients lost more than one fixture. A significant relationship was observed between implant loss and periodontal bone loss of the remaining teeth at implant placement. Maxillary, as opposed to mandibulary implants, showed more implant loss if many implants were placed in the jaw. A significant relationship between smoking habits and implant loss was not found.

CONCLUSION

A history of periodontitis seems to be related to implant loss.

Subgingival microbiota in peri-implant mucosa lesions and adjacent teeth in partially edentulous patients

BACKGROUND

Osseointegrated dental implants have been shown to be a predictable approach to provide the adequate support for the replacement of missing teeth. It has been observed that implants showing signs of peri-implantitis contain subgingival microbiota similar to that around natural teeth with periodontal disease. This study identified the subgingival microbiota around implants with peri-implant lesions and natural teeth in partially edentulous patients.

METHODS

Clinical and radiographic parameters were recorded and microbial samples taken from 16 implants with signs of pocketing, 12 neighboring and 11 non-neighboring teeth to the affected implants in 11 patients and 15 stable implants in eight patients (controls). Samples were cultured using techniques for Enterobacteriaceae spp and facultative/anaerobic periodontal pathogens. Statistical analysis included Friedman test to establish differences between the subgingival microbiota cultured from implants and teeth and two-tailed Mann Whitney test and chi square to find differences in two separate samples (P < or = 0.05).

RESULTS

There were statistical differences between the subgingival microbiota in peri-implant lesions and stable implants for Gram-negative enteric rods (P <0.05). P. gingivalis (1.42%) was detected in peri-implant lesions but not in stable implants. A significant correlation between the subgingival microbiota from implants and neighboring teeth for Gram-negative enteric rods (P = 0.023) and implants and non-neighboring teeth for P. gingivalis (P = 0.042) was found. The frequency detection of Gram-negative enteric rods (75%) and P. intermedia/nigrescens (25%) was higher in peri-implant lesions (P <0.05).

CONCLUSIONS

The subgingival microbiota in peri-implant lesions showed high levels of periodontopathic bacteria and superinfecting bacteria compared to healthy stable implants. The role of superinfecting bacteria in the pathogenesis of peri-implant lesions needs further investigation.

Early colonization of non-submerged dental implants in patients with a history of advanced aggressive periodontitis

The aim of the study was to evaluate the early colonization of non-submerged implants over a 6-month period in partially edentulous patients treated for advanced aggressive periodontal disease. In 22 patients treated for advanced aggressive periodontitis and in a supportive maintenance program for a period between 12 and 240 months at implant surgery, a total of 68 non-submerged dental implants were installed. Patients had a plaque score below 20%, and less than 20% of the pockets around the teeth were bleeding on probing (BOP). Using DNA-probes (micro-IDent), the presence and concentration of five periodontal pathogens (Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythensis (Tf) and Treponema denticola (Td)) were determined in the five deepest pockets of the rest dentition pre-operatively and after 6 months as well as five places around each implant 10 days, 1 month, 3 months and 6 months after surgery. In each patient, a test to determine the genotype interleukin-1 (IL-1) was performed (PST - micro-IDent). After 6 months, no difference in microbial composition as compared with baseline was found around the teeth in five patients, in 12 minute differences and in five patients important differences were observed. Ten days after surgery, three patients had a complete similar bacterial composition between teeth and implants. In 14 patients, the composition was fairly similar, while large differences in composition and concentration occurred in five patients. This microbiota around the implants remained almost unchanged over a 6-month period and did not hamper the clinical and radiographic osseointegration and did not lead to peri-implantitis, mucositis or initiation of bone destruction.

Dynamics of initial subgingival colonization of ‘pristine’ peri-implant pockets

BACKGROUND

Periodontitis and peri-implantitis are linked to the presence of several key pathogens. The treatment of these infectious processes therefore involves the reduction/eradication of bacteria associated with periodontitis.

METHODS

This prospective, split-mouth, single-blind study followed the colonization of 'pristine' sulci created in 42 partially edentulous patients during implant surgery (e.g. abutment connection). The hypothesis was that the composition of the maturing subgingival plaque in these 'fresh' peri-implant pockets would soon (within 2 weeks) be comparable to the subgingival microbiota of teeth with similar clinical parameters (reference sites), including the presence of bacteria associated with periodontitis. Per patient, four subgingival plaque samples were taken from shallow and medium pockets around implants (test sites), and teeth within the same quadrant (undisturbed microbiota as control sites), 1, 2, 4, 13, 26 and 78 weeks after abutment connection, respectively. The samples were analysed by either checkerboard DNA-DNA hybridization, or cultural techniques, or real-time polymerase chain reaction (PCR) for intra-subject comparisons (teeth vs. implant, for comparable probing depths).

RESULTS

Checkerboard DNA-DNA hybridization and real-time PCR revealed a complex microbiota (including several pathogenic species) in the peri-implant pockets within 2 weeks after abutment connection. After 7 days, the detection frequency for most species (including the bacteria associated with periodontitis) was already nearly identical in samples from the fresh peri-implant pockets (5% and 20% of the microbiota belonging to red and orange complex, respectively) when compared with samples from the reference teeth. Afterwards (e.g. between weeks 2 and 13), the number of bacteria in peri-implant pockets only slightly increased (+/-0.1 log value), with minor changes in the relative proportions of bacteria associated with periodontitis (8% and 33% of the microbiota belonging to red and orange complex, respectively). Although small differences were seen between teeth and implants at week 2 with cultural techniques, a striking similarity in subgingival microbiota was found with this technique from month 3 on, with nearly identical detection frequencies for bacteria associated with periodontitis for both abutment types.

CONCLUSIONS

This study indicates that the initial colonization of peri-implant pockets with bacteria associated with periodontitis occurs within 2 weeks.

Microbiological and clinical outcomes and patient satisfaction for two treatment options in the edentulous lower jaw after 10 years of function

BACKGROUND

Long-term data on microbiological and clinical outcome as well as on patient satisfaction after implant therapy in the edentulous mandible are limited. Especially comparisons between fixed full prostheses (FFPs) and overdentures (ODs), or between anchoring systems for the latter are scarce.

AIM

This study aimed to evaluate both of these parameters at the 10-year follow-up in a group of fully edentulous patients rehabilitated via an OD or a FFP (the latter to allow inter-group comparison).

MATERIAL AND METHODS

A total of 37 fully edentulous patients (25 ODs, 12 FFPs, age at implant installation ranged from 36 to 85 years) participated in this study. All subjects received their implants (Branemark System, Nobel Biocare AB, Gothenburg, Sweden) 10 years previously. For the ODs different attachment systems (bar, magnets, ball) had been applied that allowed a further intra-group comparison. At the follow-up visit, 10 years after the abutment insertion, a series of periodontal parameters were recorded, long-cone radiographs were taken and subgingival plaque samples were collected for analysis using checkerboard DNA-DNA hybridization. The clinical and radiographic data were recorded at abutment connection and after 1 and 10 years.

RESULTS

After 10 years of loading, mean plaque and bleeding indices and changes in attachment or marginal bone level were not significantly different, neither between the OD and FFP group, nor within the OD group. The marginal bone loss between abutment connection and year 10 was 0.86 and 0.73 mm for OD and FFP groups, respectively. The subgingival microbiota at implant sites from all (sub)-groups was comparable, with low numbers of DNA counts (+/-10 x 10(5)) but high detection frequencies of Actinobacillus actinomycetemcomitans (>90%), Porphyromonas gingivalis (>85%) and Tannerella forsythensis (30%). The composition of the subgingival microbiota was influenced by probing depth and bleeding tendency. Patient satisfaction was very high for both types of prosthetic rehabilitation. The FFP group scored only slightly better for chewing comfort and general satisfaction.

CONCLUSION

These data indicate that from the clinical and microbiological standpoint, as well as patient satisfaction, both an OD and a FFP offer a favourable long-term outcome.

A review of selected dental literature on evidence-based treatment planning for dental implants: Report of the Committee on Research in Fixed Prosthodontics of the Academy of Fixed Prosthodontics

This literature review summarizes research with the aim of providing dentists with evidence-based guidelines to apply when planning treatment with osseointegrated implants. Peer-reviewed literature published in the English language between 1969 and 2003 was reviewed using Medline and hand searches. Topics reviewed include systemic host factors such as age, gender, various medical conditions, and patient habits, local host factors involving the quantity and quality of bone and soft tissue, presence of present or past infection and occlusion, prosthetic design factors, including the number and arrangement of implants, size and coatings of implants, cantilevers and connections to natural teeth, and methods to improve outcomes of implant treatment in each category. The review demonstrated that there is no systemic factor or habit that is an absolute contraindication to the placement of osseointegrated implants in the adult patient, although cessation of smoking can improve outcome significantly. The most important local patient factor for successful treatment is the quality and quantity of bone available at the implant site. Specific design criteria are provided, including guidelines for spacing of implants, size, materials, occlusion, and fit. Limitations in the current body of knowledge are identified, and directions for future research are suggested.

In vitro evaluation of the biocompatibility of contaminated implant surfaces treated with an Er : YAG laser and an air powder system

Titanium platelets with a sand-blasted and acid-etched surface were coated with bovine serum albumin and incubated with a suspension of Porphyromonas gingivalis (ATCC 33277). Four groups with a total of 48 specimens were formed. Laser irradiation of the specimens (n = 12) was performed on a computer-controlled XY translation stage at pulse energy 60 mJ and frequency 10 pps. Twelve specimens were treated with an air powder system. After the respective treatment, human gingival fibroblasts were incubated on the specimens. The proliferation rate was determined by means of fluorescence activity of a redox indicator (Alamar Blue Assay) which is reduced by metabolic activity related to cellular growth. Proliferation was determined up to 72 h. Contaminated and non-treated as well as sterile specimens served as positive and negative controls. Proliferation activity was significantly (Mann-Whitney U-test, P < 0.05) reduced on contaminated and non-treated platelets when compared to sterile specimens. Both on laser as well as air powder-treated specimens, cell growth was not significantly different from that on sterile specimens. Air powder treatment led to microscopically visible alterations of the implant surface whereas laser-treated surfaces remained unchanged. Both air powder and Er : YAG laser irradiation have a good potential to remove cytotoxic bacterial components from implant surfaces. At the irradiation parameters investigated, the Er : YAG laser ensures a reliable decontamination of implants in vitro without altering surface morphology.

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.

Effect of implant design on survival and success rates of titanium oral implants: a 10-year prospective cohort study of the ITI Dental Implant System

AIM

The aim of this 10-year study (observation time 8-12 years, mean: 10 years) was to compare the survival rates, success rates and incidences of biological complications using three different implant designs of the ITI Dental Implant System.

MATERIAL AND METHODS

In 89 dental patients treated comprehensively, a total of 112 hollow screw (HS), 49 hollow cylinder (HC) and 18 angulated hollow cylinder (AHC) implants were installed depending on the available bone volume and according to prosthetic needs. One and 10 years after surgical placement, clinical and radiographic parameters were assessed. The incidences of peri-implantitis according to various thresholds were registered over 10 years of maintenance.

RESULTS

Success criteria at 10 years were set at: pocket probing depth (PPD)< or =5 mm, bleeding on probing (BoP)-, bone loss < 0.2 mm annually. The survival rate for HS was 95.4%, for HC 85.7% and for AHC 91.7%. Ninety percent of all the HS, 71% of the HC and 88% of the AHC did not present with an incidence of peri-implantitis over the 10 years, HC having significantly higher incidence of peri-implantitis than HS (P< 0.004). With the success criteria set above, a success rate for HS of 74%, for HC of 63% and for AHC of 61% was identified at 10 years. However, including a definition of PPD< or =6 mm, BoP - and bone loss < 0.2 mm annually for success, the rates for HS were 78%, for HC 65% and for AHC 67%, respectively. Basing success criteria purely on clinical parameters (without radiographic analysis), such as: PPD< or =5 mm and BoP-, the success rates increased to 90%, 76% and 89%, respectively. With PPD< or =6 mm and BoP - as success criteria chosen, the respective rates were 94%, 82% and 94% for HS, HC and AHC implants, respectively.

CONCLUSIONS

A significantly higher survival rate as well as a significantly lower incidence of peri-implantitis was identified for hollow screw design ITI Dental Implants after 10 years of service when compared to hollow cylinder design ITI Dental Implants (95.4% vs. 85.7%; 10% vs. 29%). Depending on the setting of the threshold criteria for success, success rates are highly variable and hence, reporting of success rates with elaboration on the criteria set appears crucial for comparison of different studies.

Long-term implant prognosis in patients with and without a history of chronic periodontitis: a 10-year prospective cohort study of the ITI Dental Implant System

AIM

The aim of this 10-year study was to compare the failure, success and complication rates between patients having lost their teeth due to periodontitis or other reasons.

MATERIAL AND METHODS

Fifty-three patients who received 112 hollow screw implants (HS) of the ITI Dental Implant System were divided into two groups: group A - eight patients with 21 implants having lost their teeth due to chronic periodontitis; group B - forty five patients with 91 implants without a history of periodontitis. One and 10 years after surgical placement, clinical and radiographic parameters were assessed. The incidences of peri-implantitis were noticed over the 10 years of regular supportive periodontal therapy.

RESULTS

Success criteria at 10 years were set at: pocket probing depth (PPD) <or=5 mm, bleeding on probing (BoP-, bone loss <0.2 mm annually. The survival rate for the group with a past history of chronic periodontitis (group A) was 90.5%, while for the group with no past history of periodontitis (group B) it was 96.5%. Group A had a significantly higher incidence of peri-implantitis than group B (28.6% vs. 5.8%). With the success criteria set, 52.4% in group A and 79.1% of the implants in group B were successful. With a threshold set at PPD <or=6 mm, BoP- and bone loss <0.2 mm annually, the success rates were elevated to 62% and 81.3% for groups A and B, respectively. Relying purely on clinical parameters of PPD <or=5 mm and BoP-, the success rates were at 71.4% and 94.5%, and with a threshold set at PPD <or=6 mm and BoP-, these proportions were elevated to 81% and 96.7% for groups A and B, respectively.

CONCLUSIONS

Patients with implants replacing teeth lost due to chronic periodontitis demonstrated lower survival rates and more biological complications than patients with implants replacing teeth lost due to reasons other than periodontitis during a 10-year maintenance period. Furthermore, setting of thresholds for success criteria is crucial to the reporting of success rates.

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.

Infectious risks for oral implants: a review of the literature

The use of oral implants in the rehabilitation of partially and fully edentulous patients is widely accepted even though failures do occur. The chance for implants to integrate can for example be jeopardised by the intra-oral presence of bacteria and concomitant inflammatory reactions. The longevity of osseointegrated implants can be compromised by occlusal overload and/or plaque-induced peri-implantitis, depending on the implant geometry and surface characteristics. Animal studies, cross-sectional and longitudinal observations in man, as well as association studies indicate that peri-implantitis is characterised by a microbiota comparable to that of periodontitis (high proportion of anaerobic Gram-negative rods, motile organisms and spirochetes), but this does not necessarily prove a causal relationship. However, in order to prevent such a bacterial shift, the following measures can be considered: periodontal health in the remaining dentition (to prevent bacterial translocation), the avoidance of deepened peri-implant pockets, and the use of a relatively smooth abutment and implant surface. Finally, periodontitis enhancing factors such as smoking and poor oral hygiene also increase the risk for peri-implantitis. Whether the susceptibility for periodontitis is related to that for peri-implantitis may vary according to the implant type and especially its surface topography.

In vitro study of the effect of titanium on porphyromonas gingivalis in the presence of metronidazole and spiramycin

Septic peri-implantitis is the main clinical complication encountered following the insertion of titanium implants. It may be resistant to conventional antibiotic treatments. Reports in the literature about antibiotic behavior in the presence of titanium remain controversial. They vary from a bacteriostat to a decreased effect of antibiotic. This study examined, in vitro, the viability of Porphyromonas gingivalis, frequently associated with periodontal diseases, in the presence of titanium and antibiotics (spiramycin and metronidazole alone or in combination). Viability of P. gingivalis was determined, versus a standard curve using the Live/dead Baclight Bacteria Viability Kit on 96 well microplates. The results of 48 experiments (60 measurements each) were compiled in a database and compared to each other using the chi2p < 0.05 test. When used alone, titanium enhanced bacterial growth as the nickel-chrome control. However, when titanium was used in the presence of antibiotics, antibiotics kept their own effects. Even more, titanium was shown to potentialize the effect of metronidazole. The strengthening of effectiveness of metronidazole by titanium may be due to the oxidation potential of the metal. This chemical property could explain the conflicting data reported in the literature.

Clinical and microbiological evaluation of ligature-induced peri-implantitis and periodontitis in dogs

The purpose of this study was to evaluate the attachment loss around teeth and implants by clinical and microbiological analysis. The mandibular premolars were extracted in 5 mongrel dogs and, 3 months later, two titanium implants were installed on each side of the mandible and, after another 3 months, abutment connection was performed. Plaque control in the implants and maxillary premolars was maintained for two weeks prior to the start of the main experiment. On day 0 and 30 days after ligature placement, microbiological samples were obtained and relative attachment level was measured for the teeth and implants. The presence of Porphyromonas gingivalis, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, Prevotella intermedia and Prevotella nigrescens was evaluated by polymerase chain reaction technique on day 0 and 30 days after ligature placement. None of the above bacteria were detected on day 0. Thirty days after ligature placement, P. gingivalis was present in 95% and 85% and B. forsythus was present in 80% and 85% of the implants and teeth sites, respectively. Statistical analysis (one-way RM-ANOVA) showed a significant difference (P<0.01) between pre- and post-induction measurements around teeth and implants. However, there was no significant difference (P=0.41) in the rate of attachment loss, between periodontitis and peri-implantitis. It can be concluded that: (1) P. gingivalis and B. forsythus were strongly associated with induced peri-implantitis and periodontitis, and (2) induced peri-implantitis and periodontitis presented a similar rate of attachment loss.

Microbial analysis of bone collected during implant surgery: a clinical and laboratory study

Dental implant surgery produces bone debris which can be used to correct bone defects in the "simultaneous-augmentation" technique. However, this debris is potentially contaminated with oral bacteria. Therefore, this study examined bone debris collected during dental implant surgery in order 1) to identify the microbial contaminants and 2) to compare the effects of two different aspiration protocols on the levels of microbial contamination. Twenty-four partially dentate patients were randomly allocated into two equal groups and underwent bone collection using the Frios Bone Collector during surgery to insert two endosseous dental implants. In group S (using a stringent aspiration protocol), bone collection occurred within the surgical site only. In group NS (utilizing a non-stringent aspiration protocol), bone collection and tissue fluid control was achieved using the same suction tip. Bone samples were immediately transported for microbial analysis. Colonial and microscopic morphology, gaseous requirements and identification kits were utilized for identification of the isolated microbes. Twenty-eight species were identified including a number associated with disease, in particular, Enterococcus faecalis and Staphylococcus epidermidis as well as the anaerobes Actinomyces odontolyticus, Eubacterium sp., Prevotella intermedia, Propionibacterium propionicum and Peptostreptococcus asaccharolyticus. In group S (stringent aspiration protocol), significantly fewer organisms were found than in group NS, the non-stringent aspiration protocol (P=0.001). Gram-positive cocci dominated the isolates from both groups. It is concluded that if bone debris is collected for implantation around dental implants, it should be collected with a stringent aspiration protocol (within the surgical site only) to minimize bacterial contaminants.

Bacterial adhesion of Actinobacillus actinomycetemcomitans serotypes to titanium implants: SEM evaluation. A preliminary report

BACKGROUND

In this study, the adherence ability of Actinobacillus actinomycetemcomitans serotypes to titanium implant surfaces was evaluated to demonstrate if any selective adherence occurs according to the serotypes of the microorganism.

METHODS

The study material included 3 reference strains of A. actinomycetemcomitans serotypes a, b, and c (ATCC 29523, ATCC 43718, ATCC 33384) and 2 clinical isolates of A. actinomycetemcomitans serotypes d and e (IDH 781, IDH 1705), together with commercially available titanium blade implants. For each strain, bacterial suspensions with identical concentrations (5 x 10(7) cells/ml) were prepared and 0.5 ml of each was added on to the implant surfaces, which had been precoated with glycine-bovine serum albumin (BSA). After incubation at 37 degrees C for 60 minutes in 5% CO2 in air, the implants with attached bacteria were prepared for scanning electron microscopic (SEM) observations. Bacterial adhesion was quantified on the textured body surfaces of the implants, and results were statistically analyzed with analysis of variance followed by Duncan's test. The surface ultrastructure of the bacterial cells was also evaluated descriptively.

RESULTS

The tested strains adhered to implant surfaces in different quantities. Serotype a (ATCC 29523) showed the highest adherence affinity (statistically significant, P <0.01). When compared with each other, serotypes b, c, and d (ATCC 43718, ATCC 33384, and IDH 781) attached equally well, whereas serotype e (IDH 1705) had a statistically significant low adherence capability.

CONCLUSIONS

It is suggested that in vitro A. actinomycetemcomitans adhesion to implant surfaces is strain dependent.