Long-term outcomes and prognostic factors of surgical treatment of peri-implantitis - A retrospective study.

AIM: To evaluate long-term outcomes and prognostic factors of non-reconstructive surgical treatment of peri-implantitis. MATERIALS AND METHODS: One hundred forty-nine patients (267 implants) were surgically treated for peri-implantitis and followed for an average of 7.0 (SD: 3.6) years. The primary outcome was implant loss. Additional bone loss and surgical retreatment were secondary outcomes. Patient/implant characteristics, as well as clinical and radiographic parameters collected prior to initial surgery, were evaluated as potential predictors of implant loss. Flexible parametric survival models using restricted cubic spline functions were used; 5- and 10-year predicted rates of implant loss were calculated according to different scenarios. RESULTS: Fifty-three implants (19.9%) in 35 patients (23.5%) were lost during the observation period. Implant loss occurred after a mean period of 4.4 (SD: 3.0) years and was predicted by implant surface characteristics (modified surface; HR 4.5), implant length (HR 0.8 by mm), suppuration at baseline (HR 2.7) and disease severity (baseline bone loss: HR 1.2 by mm). Estimates of 5- and 10-year implant loss ranged from 1% (best prognostic scenario; initial bone loss <40% of implant length, turned implant surface and absence of suppuration on probing (SoP)) to 63% (worst prognostic scenario; initial bone loss ≥60% of implant length, modified implant surface and SoP) and from 3% to 89%, respectively. Surgical retreatment was performed at 65 implants (24.3%) in 36 patients (24.2%) after a mean time period of 4.5 (3.1) years. In all, 59.5% of implants showed additional bone loss, were surgically retreated or lost. CONCLUSIONS: Recurrence of disease is common following surgical treatment of peri-implantitis. The strongest predictor for implant loss was implant surface characteristics. Implant length as well as suppuration and disease severity at baseline were also relevant factors.

Accuracy of bone-level assessments following reconstructive surgical treatment of experimental peri-implantitis.

AIMS: The purpose of this study was to evaluate the accuracy of bone-level assessments using either cone-beam computed tomography (CBCT), intra-oral peri-apical (PA) radiographs or histology following reconstructive treatment of experimental peri-implantitis. MATERIALS AND METHODS: Six Labrador dogs were used. Experimental peri-implantitis was induced 3 months after implant placement. Surgical treatment of peri-implantitis was performed and peri-implant defects were allocated to one of four treatment categories; no augmentation, bone graft materials with or without a barrier membrane. Six months later, intra-oral PA radiographs and block biopsies from all implants sites were obtained. Marginal bone levels (MBLs) were measured using PA radiographs, CBCT and histology. RESULTS: Significant correlations of MBL assessments were observed between the three methods. The measurements in PA radiographs consistently resulted in an overestimation of the bone level of about 0.3-0.4 mm. The agreement between the methods was not influenced by the use of bone substitute materials in the management of the osseous defects. CONCLUSIONS: Although MBL assessments obtained from PA radiographs showed an overestimation compared to MBL assessments on corresponding CBCT images and histological sections, PA radiographs can be considered a reliable technique for peri-implant bone-level evaluations following reconstructive surgical therapy of experimental peri-implantitis.

Influence of implant geometry and osteotomy design on early bone healing: A pre-clinical in vivo study.

OBJECTIVES: To analyze the early stages of osseointegration around implants with different geometry following installation in sites using different osteotomy protocols. MATERIALS AND METHODS: Two types of implants were installed using regular or modified (reduced diameter) osteotomy protocols in mandibular premolar/molar regions following tooth extraction in six dogs. Three implant site categories were created: Reference (A implant and regular osteotomy), Test-1 (B implant and regular osteotomy), and Test-2 (B implant and modified osteotomy). Implant installation procedures were repeated after 4 and 6 weeks. The insertion torque (ITQ) was measured during implant installation and resonance frequency analysis providing implant stability quotient (ISQ) values was performed following implant installation and once every week during the course of the study. Biopsies were obtained immediately after the 3rd installation procedure and prepared for histological analysis. RESULTS: The modified osteotomy protocol created a higher insertion torque (ITQ). The analysis also revealed a correlation between insertion torque at implant installation and radiographic bone loss after 6 weeks of healing. The decline in ISQ values during healing was more pronounced at Test-2 than other sites. While the degree of bone-to-implant contact (BIC%) in the marginal area was similar in test and reference sites at 6 weeks of healing, Test-2 implants presented with a significantly higher BIC% in the mid and apical areas than Test-1 implants. CONCLUSIONS: It is suggested that placement of implants in undersized osteotomy sites will result in an increased remodeling of the cortical bone during the early healing process.

Cellular expression of DNA damage/repair and reactive oxygen/nitrogen species in human periodontitis and peri-implantitis lesions.

AIM OF THE STUDY: To evaluate differences in the cellular expression of DNA damage/repair and reactive oxygen/nitrogen species between human periodontitis and peri-implantitis lesions. MATERIAL AND METHODS: 40 patients presenting with generalized severe periodontitis and 40 patients with severe peri-implantitis were included. Soft tissue biopsies were collected from diseased sites in conjunction with surgical therapy and prepared for histological analysis. Four regions of interest were identified: the pocket epithelium (PE), the infiltrated connective tissue (ICT), which was divided into one inner area facing the PE (ICT-1) and one outer area (ICT-2). A non-infiltrated connective tissue area (NCT) lateral of the ICT was also selected. RESULTS: It was demonstrated that the ICT of peri-implantitis specimens was considerably larger and contained significantly larger area proportions and densities of CD68-, MPO- and iNOS-positive cells than that of periodontitis samples. Cellular densities were overall higher in the inner ICT zone lateral of the PE (ICT-1) than in the outer ICT compartment (ICT-2). While the NCT area lateral of the ICT comprised significantly larger proportions and densities of y-H2AX-, iNOS-, NOX2-, MPO- and PAD4/MPO-positive cells in peri-implantitis than in periodontitis sites, a reverse difference was noted for the area proportion and density of 8-OHdG-positive cells in the PE. CONCLUSIONS: It is suggested that peri-implantitis lesions are associated with an enhanced and upregulated host response and contain larger numbers of neutrophils, macrophages and iNOS-positive cells than periodontitis lesions.

Spontaneous progression of experimental peri-implantitis in augmented and pristine bone: A pre-clinical in vivo study.

OBJECTIVE: To examine the progression of experimental peri-implantitis around different implants placed in augmented and pristine sites. MATERIALS AND METHODS: Six labrador dogs were used. Three months after tooth extraction, four implants with different surface modifications were installed on each side of the mandible. A standard osteotomy was applied on one side, while on the contralateral side the osteotomy was modified, resulting in a gap between the implant and the bone wall. The gap was filled with a bone substitute and covered by a resorbable membrane. Three months after implant installation, implants were exposed and healing abutments were connected. Two months later, oral hygiene procedures were abandoned and a cotton ligature was placed in a submarginal position around the neck of all implants and kept in place for 4 weeks. Following ligature removal, plaque formation continued for 6 months (spontaneous progression period). Radiographs were obtained throughout the experiment, and biopsies were collected and prepared for histological evaluation at the end of the spontaneous progression period. RESULTS: Differences in bone loss during the spontaneous progression period between pristine and augmented sites were small. The size and vertical dimension of the peri-implantitis lesion were larger at augmented than at pristine sites. Implants with non-modified surfaces exhibited smaller amounts of bone loss and smaller dimensions of peri-implantitis lesions than implants with modified surfaces. CONCLUSION: Small differences in spontaneous progression of peri-implantitis were detected between pristine and augmented sites. Implants with modified surfaces exhibited more bone loss and larger lesions than implants with non-modified surfaces, irrespective of the type of surrounding bone.

Risk for recurrence of disease following surgical therapy of peri-implantitis-A prospective longitudinal study.

OBJECTIVES: The aim of the present prospective study was to assess the risk for disease recurrence following surgical therapy of peri-implantitis. MATERIAL & METHODS: 73 patients (130 implants) treated surgically for peri-implantitis were examined at 1 and 5 years after therapy. The primary outcome was recurrence/progression of disease defined as any of the following events: (a) bone loss >1.0 mm, (b) surgical retreatment, (c) implant removal/loss after year 1. Patient- and implant-related parameters as well as 1-year outcomes were evaluated as potential predictors through multiple logistic regression analysis. RESULTS: 57 implants (44%) displayed recurrence/progression of peri-implantitis during follow-up. Among these, 27 implants were removed. Residual deep probing pocket depth (≥6 mm; odds ratio 7.4; 95% confidence interval 2.8-19.3) and reduced marginal bone level (OR 1.4; 95%CI 1.1-1.7) at 1 year after surgery constituted risk factors for recurrence/progression of disease. Furthermore, implants with modified surfaces were at higher risk than implants with non-modified surfaces (OR 5.1; 95%CI 1.6-16.5). CONCLUSION: Implants with (a) residual deep probing pocket depth, (b) reduced marginal bone level, or (c) modified surfaces following surgical therapy of peri-implantitis present with increased risk for recurrence/progression.

Re-osseointegration following reconstructive surgical therapy of experimental peri-implantitis. A pre-clinical in vivo study.

OBJECTIVE: To evaluate the effect of bone substitute materials on hard and soft tissue healing in reconstructive surgical therapy of experimental peri-implantitis at implants with different surface characteristics. MATERIAL AND METHODS: Six female, Labrador dogs were used. 3 months after tooth extraction, four implants with two different surface characteristics (A and B) were installed on each side of the mandible. Experimental peri-implantitis was induced 3 months later. During surgical treatment of peri-implantitis, the implants were cleaned with curettes and cotton pellets soaked in saline. The implant sites were allocated to one of four treatment categories; (a) Group C; no augmentation, (b) Group T1; bone defect filled with deproteinized bovine bone mineral (c) Group T2; bone defect filled with a biphasic bone graft material, (d) Group T3; bone defect filled as T1 and covered with a collagen membrane. Clinical and radiological examinations were performed, and biopsies were obtained and prepared for histological analysis 6 months after peri-implantitis surgery. RESULTS: Implant B (smooth surface) sites showed significantly (a) larger radiographic bone level gain, (b) enhanced resolution of peri-implantitis lesions, and (c) larger frequency of re-osseointegration than implant A (moderately rough surface) sites. Implant B sites also showed superior preservation of the mucosal margin. Differences between bone substitute materials and control procedures were overall small with limited advantages for T1 and T2 sites. CONCLUSION: Healing following reconstructive surgical treatment of experimental peri-implantitis was superior around implants with a smooth surface than implants with a moderately rough surface. Benefits of using bone substitute materials during surgical therapy were overall small.

Surgical treatment of peri-implantitis: 3-year results from a randomized controlled clinical trial.

OBJECTIVES: This study reports on the 3-year follow-up of patients enrolled in a randomized controlled clinical trial on surgical treatment of advanced peri-implantitis. MATERIAL AND METHODS: A total of 100 patients with advanced peri-implantitis were randomly assigned to one of four treatment groups. Surgical therapy aiming at pocket elimination was performed and, in three test groups, supplemented by either systemic antibiotics, use of an antiseptic agent for implant surface decontamination or both. Outcomes were evaluated after 1 and 3 years by means of clinical and radiological examinations. Differences between groups were explored by regression analysis. RESULTS: Clinical examinations at 3 years after treatment revealed (i) improved peri-implant soft tissue health with a mean reduction in probing depth of 2.7 mm and a reduction in bleeding/suppuration on probing of 40% and (ii) stable peri-implant marginal bone levels (mean bone loss during follow-up: 0.04 mm). Implant surface characteristics had a significant impact on 3-year outcomes, in favour of implants with non-modified surfaces. Benefits of systemic antibiotics were limited to implants with modified surfaces and to the first year of follow-up. CONCLUSION: It is suggested that surgical treatment of peri-implantitis is effective and that outcomes of therapy are affected by implant surface characteristics. Potential benefits of systemic antibiotics are not sustained over 3 years.

The effect of the local use of chlorhexidine in surgical treatment of experimental peri-implantitis in dogs.

AIM: To evaluate the effect of surgical treatment of experimental peri-implantitis at implants with different surface characteristics using different anti-infective procedures. MATERIAL AND METHODS: Four implants with different surface characteristics (A: TiOblast, B: OsseoSpeed, C: AT-I, D: TiUnite) were installed in a randomized order in each side of the mandible in 6 labrador dogs 3 months after tooth extraction. Experimental peri-implantitis was induced 3 months later. Surgical treatment of peri-implantitis was performed. The implants were cleaned with gauze soaked in either saline (control) or chlorhexidine (test). Clinical and radiographical examinations were performed and microbiological samples were taken during a 6-month period after surgery. Biopsies were obtained and prepared for histological analysis. RESULTS: Clinical signs of soft tissue inflammation were reduced after surgical therapy in most test and control sites. While the analysis of bone level alterations in radiographs together with histological and microbiological assessments of resolution of peri-implantitis lesions failed to demonstrate statistically significant differences between test and control procedures, the evaluations disclosed significant differences between implant D and implants A, B and C on treatment outcome. CONCLUSION: It is suggested that (i) the local use of chlorhexidine has minor influence on treatment outcome, (ii) resolution of peri-implantitis following surgical treatment without the adjunctive use of local and systemic antimicrobial agents is possible and (iii) the results are influenced by implant surface characteristics.

Microbiota in experimental periodontitis and peri-implantitis in dogs.

AIM: To analyze the microbial profile around teeth and implants following ligature removal in experimental periodontitis and peri-implantitis in dogs. MATERIAL AND METHODS: Four implants with similar geometry and with two different surface characteristics (implant A: turned/implant B: TiUnite; NobelBiocare AB) were placed pairwise in the right side of the mandible 3 months after tooth extraction in five dogs. Experimental periodontitis and peri-implantitis were initiated 3 months later by ligature placement around implants and mandibular premolars and plaque formation. The ligatures were removed after 10 weeks. Microbial samples were obtained using paper points immediately after ligature removal, at 10 and 25 weeks after ligature removal. The microbiological analysis was performed by "checkerboard" DNA-DNA hybridization, including a panel of 16 bacterial species. RESULTS: The amount of bone loss that occurred during the period following ligature removal was significantly larger at implants with a modified surface than at implants with a turned surface and at teeth. The microbiological analysis revealed that the total bacterial load increased during the period following ligature removal and established an anaerobic Gram-negative microflora. CONCLUSION: It is suggested that the large variation in regard to the microbial profiles makes interpretation of a correlation between disease progression and microbial profiles difficult.

Experimental periodontitis and peri-implantitis in dogs.

AIM: To analyze the tissue reactions following ligature removal in experimental periodontitis and peri-implantitis in dogs. MATERIAL AND METHODS: Four implants with similar geometry and with two different surface characteristics (turned/TiUnite Nobel BioCare AB, Göteborg) were placed pair-wise in a randomized order in the right side of the mandible 3 months after tooth extraction in 5 dogs. Experimental peri-implantitis and periodontitis were initiated 3 months later by ligature placement around implants and mandibular premolars and plaque formation. The ligatures were removed after 10 weeks, and block biopsies were obtained and prepared for histological analysis 6 months later. RESULTS: It was demonstrated that the amount of bone loss that occurred during the period following ligature removal was significantly larger at implants with a modified surface than at implants with a turned surface and at teeth. The histological analysis revealed that peri-implantitis sites exhibited inflammatory cell infiltrates that were larger, extended closer to the bone crest and contained larger proportions of neutrophil granulocytes and osteoclasts than in periodontitis. CONCLUSION: It is suggested that lesions produced in experimental periodontitis, and peri-implantitis are different and that implant surface characteristics influence the inflammatory process in experimental peri-implantitis and the magnitude of the resulting tissue destruction.

Modified free gingival graft technique for treatment of gingival recession defects at mandibular incisors: A randomized clinical trial.

BACKGROUND: The aim of this study was to evaluate clinical and patient-reported outcomes following surgical root coverage at RT1 gingival recession defects at mandibular incisors, using either a conventional free gingival graft (FGG) or a modified FGG (ModFGG). METHODS: Total of 30 patients with RT1 gingival recessions at mandibular incisors were enrolled and randomly allocated to either a control (FGG) or test group (ModFGG). Evaluations of clinical changes (recession depth, height of keratinized tissue) and patient satisfaction were performed over a follow-up period of 12 months. Post-surgical changes of keratinized tissue height (shrinkage) were assessed from 1 month and onward. RESULTS: ModFGG resulted in more pronounced root coverage at 1 year compared to FGG (91.8% vs. 60.7%, p < 0.001). Height of keratinized tissue was improved by 4.2 and 2.2 mm (p < 0.001), respectively, with significantly less shrinkage in ModFGG. Post-surgical morbidity was significantly lower for ModFGG at 2 weeks and patient satisfaction was significantly higher 12 months after treatment (9.1 vs. 5.4; p < 0.001). CONCLUSIONS: ModFGG represents a valid approach for the management of RT1 recession defects at mandibular incisors. The technique is superior to traditional FGG in terms of root coverage, the gain of keratinized tissue height, and patient satisfaction.

The expanded mesh free gingival graft: A novel approach to increase the width of keratinized mucosa.

BACKGROUND: The importance of an adequate amount of peri-implant keratinized tissue and attached mucosa has recently been emphasized. This manuscript presents preliminary findings of a novel approach for increasing the width of keratinized mucosa (KM) around dental implants using a mesh free gingival graft (mesh-FGG). METHODS: Two healthy adults were treated as part of this study. After implant placement, a large edentulous alveolar ridge with shallow vestibule and minimal amount of KM was treated in both subjects (one in the posterior mandible and the other in the anterior mandible) with the combination of an apically positioned flap and a mesh-FGG. Clinical, esthetic and patient-reported outcomes were observed at approximately 4-month time points. RESULTS: All sites healed uneventfully after the treatments. In both cases, increased vestibule depth, soft-tissue thickness, and width of peri-implant KM were obtained. The patients did not report any accessory discomfort. Four months following the grafting procedure, good overall esthetic outcome was observed with minimal color disparity and graft demarcation. CONCLUSIONS: Width of KM around dental implants can be increased using a mesh-FGG. Randomized controlled clinical studies comparing mesh-FGG to conventional FGG and other commonly applied techniques are required to assess the long-term efficacy of this novel technique in terms of soft-tissue thickness, width of peri-implant KM, and patient-reported outcomes. KEY POINTS: Principal Findings: Meshed-FGG allowed an expansion of the length of the harvested graft. This results in coverage of large recipient sites, increase in height of KM and good aesthetic integration of the graft.

Modified Free Gingival Graft Technique for Root Coverage at Mandibular Incisors: A Case Series.

Numerous surgical techniques for root coverage have been suggested with different degrees of success, as assessed by the proportion of complete root coverage. Mandibular incisors, teeth with a high frequency of gingival recession defects (GRDs), were associated with the least favorable outcomes due to unfavorable anatomical conditions. In the present series of three cases, a modified version of the free gingival graft technique for the purpose of root coverage at mandibular incisors is illustrated. The purpose of the modification of the original technique was to achieve improved blood supply from the recipient site to the graft, with the ultimate aim of enhancing predictability and outcomes of the procedure. In all included cases, complete or almost complete root coverage was achieved at challenging GRDs in the mandibular incisor area.

Peri-implantitis in a specialist clinic of periodontology. Clinical features and risk indicators.

Implant therapy has become a widely recognized treatment alternative for replacing missing teeth. Several long term follow-up studies have shown that the survival rate is high. However, complications may appear and risk indcators associated with early and late failures have been identified. The purpose of the present retrospective clinical study was to describe some clinical features of patients with clinical signs of peri-implantitis and to identify risk indicators of peri-implantitis in a population at a specialist clinic of Periodontology. In total,the material consisted of 377 implants in 111 patients with the diagnosis peri-implantitis. The mean age at the examination was found to be 56.3 years (range 22-83) for females and 64.1 years (range 27-85) for males. The mean number of remaining teeth was found to be 10.5 (S.D. 8.89) and the mean number of implants was 5.85 (S.D. 3.42). For a majority of the subjects, more than 50% of the remaining teeth had a marginal bone loss of more than 1/3 of the root length. Forty-sex percent of the patients visited regularly dental hygienists for supportive treatment. The percentage of implants with peri-implantitis was significantly increased for smokers compared to non-smokers (p = 0.04). In the group of non-smokers, 64% of the implants had the diagnosis peri-implantitis, while the corresponding relative frequency for smokers was 78%. A majority of the individuals had a Plaque index and Bleeding on probing index >50%. The median of the follow-up time after implant placement was 7.4 years and the observation period was not significantly correlated to the degree of bone loss around the implants. Among the subjects with a mean bone loss >6 mm at implants with peri-implantitis, more than 70% had a mean marginal bone loss > 1/3 of the root length of the remaining teeth. A positive and significant correlation was found between the degree of marginal bone loss in remaining teeth and the degree of bone loss around implants with peri-implantitis. In conclusion, the results of the present study indicate that smoking as well as previous history of periodontitis are associated with peri-implantitis and may represent risk factors for this disease.