Factors influencing outcomes of surgical therapy of peri-implantitis: A secondary analysis of 1-year results from a randomized clinical study.

AIM: To identify predictors of treatment outcomes following surgical therapy of peri-implantitis. MATERIALS AND METHODS: We performed a secondary analysis of data from a randomized controlled trial (RCT) comparing access flap with or without bone replacement graft. Outcomes at 12 months were probing pocket depth (PPD), bleeding on probing (BOP), soft-tissue recession (REC) and marginal bone level (MBL) change. Multilevel regression analyses were used to identify predictors. We also built an explanatory model for residual signs of inflammation. RESULTS: Baseline PPD was the most relevant predictor, showing positive associations with final PPD, REC and MBL gain, and negative association with probability of pocket closure. Smokers presented higher residual PPD. Absence of keratinized mucosa at baseline increased the probability of BOP but was otherwise not indicative of outcomes. Plaque at 6 weeks was detrimental in terms of residual PPD and BOP. Treatment allocation had an effect on REC. Final BOP was explained by residual PPD ≥6 mm and plaque at more than two sites. CONCLUSIONS: Baseline PPD was the most relevant predictor of the outcomes of surgical therapy of peri-implantitis. Pocket closure should be a primary goal of treatment. Bone replacement grafts may be indicated in aesthetically demanding cases to reduce soft-tissue recession. The importance of smoking cessation and patient-performed plaque control is also underlined.

Reconstructive surgical therapy of peri-implantitis: A multicenter randomized controlled clinical trial.

OBJECTIVE: To evaluate the potential benefit of the use of a bone substitute material in the reconstructive surgical therapy of peri-implantitis. METHODS: In this multicenter randomized clinical trial, 138 patients (147 implants) with peri-implantitis were treated surgically, randomized by coin toss to either a control (access flap surgery) or a test group (reconstructive surgery using bone substitute material). Clinical assessments, including probing pocket depth (PPD), bleeding and suppuration on probing (BOP & SOP) as well as soft tissue recession (REC), were recorded at baseline, 6 and 12 months. Marginal bone levels (MBL), measured on intra-oral radiographs, and patient-reported outcomes (PROs) were recorded at baseline and 12 months. No blinding to group allocation was performed. The primary outcome at 12 months was a composite measure including (i) implant not lost, (ii) absence of BOP/SOP at all aspects, (iii) PPD ≤5 mm at all aspects and (iv) ≤1 mm recession of mucosal margin on the buccal aspect of the implant. Secondary outcomes included (i) changes of MBL, (ii) changes of PPD, BOP%, and buccal KM, (iii) buccal REC and (iv) patient-reported outcomes. RESULTS: During follow-up, four implants (one in the test group, three in the control group) in four patients were removed due to disease progression. At 12 months, a total of 69 implants in the test and 68 implants in the control group were examined. Thus, 16.4% and 13.5% of implants in the test and control group, respectively, met all predefined criteria of the composite outcome. PPD reduction and MBL gain were 3.7 mm and about 1.0 mm in both groups. Reduction in mean BOP% varied between 45% (test) and 50% (control), without significant differences between groups. Buccal REC was less pronounced in the test group (M = 0.7, SD = 0.9 mm) when compared to controls (M = 1.1, SD = 1.5 mm). PROs were favorable in both groups without significant differences. One case of allergic reaction to the antibiotic therapy was recorded. No other adverse events were noted. CONCLUSIONS: Surgical therapy of peri-implantitis effectively improved the clinical and radiographic status at 12 months. While the use of a bone substitute material did not improve reductions of PPD and BOP, buccal REC was less pronounced in the test group. Patient satisfaction was high in both groups.

Implant-supported single-tooth restorations. A 12-year prospective study.

OBJECTIVE: The aim of this study was to evaluate prospectively the 12-year outcome of implant-supported single-tooth restorations. MATERIAL AND METHODS: Originally 45 self-tapping Astra Tech TiOblast® ST-implants were installed by a two-stage protocol in 40 subjects requiring single-tooth prosthetic replacement for a missing tooth. Clinical and radiologic examinations were performed at completion of the prosthetic treatment 4-7 months after implant installation surgery and after 5 and 12 years in function. RESULTS: At 12 years 31 patients and 35 implants were available for evaluation. The overall failure rate after 12 years was 10.3% on the subject level and 9.1% on the implant level. The mean bone loss amounted to 0.67 mm (SD 2.20) on a subject level and 0.47 mm (1.72) on an implant level. Three subjects (10%) and three implants (8.6%) were diagnosed with peri-implantitis. Five subjects had experienced technical complications; three incidences of loosening of the abutment retention screw during the first 5 years and two minor porcelain fracture of the crown (two patients) between 5- and 12-years of follow-up. CONCLUSION: The findings reported in this 12-year prospective case series suggest that the use of the Astra Tech dental implants may be a valid treatment alternative for single-tooth replacement prostheses.

Ridge preservation with the use of deproteinized bovine bone mineral.

OBJECTIVE: The aim was to examine the tissue composition of extraction sockets that had been grafted with deproteinized bovine bone mineral and allowed to heal for 6 months. MATERIAL AND METHODS: Twenty-five subjects with one tooth each scheduled for extraction and replacement with dental implants were recruited. The assigned teeth were carefully removed. The site/patient was thereafter allocated to a test or a control group. In the test group patients, Bio-Oss(®) Collagen was placed to fill the fresh extraction socket while in the controls no grafting was performed. After about 6 months of healing, a biopsy was sampled from the center of the extraction site. The specimens were decalcified, embedded in paraffin, sectioned, and stained in HTX. The proportions occupied by mineralized bone, osteoid, bone marrow, fibrous tissue, and Bio-Oss(®) particles were determined by morphometric point counting. RESULTS: Mineralized bone made up 57.4 ± 12.4% of the control sites (C) and 48.9 ± 8.5% of the T1 sites (graft material not included). The amount of bone marrow (C: 7.1 ± 6.1%, T1: 2.1 ± 3.1%) and osteoid (C: 7.3 ± 4.9%, T1: 1.9 ± 2.1%) was about five times greater in the control than in the test sites. Fibrous tissue comprised 23.1 ± 16.3% (C) and 40.0 ± 11.9% (T1). I n the T2 sites (graft material included), the percentage mineralized bone was 39.9 ± 8.6 while the proportions of bone marrow and osteoid were 1.8 ± 2.5% and 1.6 ± 1.8%. Fibrous tissue occupied 32.4 ± 9.2% and Bio-Oss(®) particles 19.0 ± 6.5% of the T2 sites. CONCLUSION: Placement of the biomaterial in the fresh extraction socket retarded healing. The Bio-Oss(®) particles were not resorbed but became surrounded by new bone. This may explain why grafted extraction sites may fail to undergo dimensional change.

Effect of immediate functional loading on osseointegration of implants used for single tooth replacement. A human histological study.

OBJECTIVE: To analyze hard tissue reactions to immediate functionally loaded single implants that were installed either with a conventional drill preparation procedure or with an osteotome preparation technique. MATERIALS AND METHODS: Thirteen subjects with two sites requiring single tooth rehabilitation by means of implants volunteered for the study. Each subject received one test (immediate functionally loaded) and one control (non-loaded) implant. In six subjects (group 1) the implants were placed using a conventional drilling procedure, whereas in the remaining seven subjects (group 2) an osteotome preparation procedure was performed. Block biopsies containing test and control implants and peri-implant bone tissues were collected at 1 month in four of the subjects in group 1 and in five subjects of group 2. The remaining implant sites were sampled at 3 months after implant placement. The biopsies were prepared for histological examination. RESULTS: Two implants of the test-2 group (osteotome preparation) representing 1 month of healing and another test-2 implant representing 3 months of healing failed to integrate. A multilevel multivariate statistical analysis demonstrated that no differences in bone-to-implant contact (BIC)% were found in between test and control implants, the density of newly formed peri-implant bone was significantly higher around test than control implants at 1 and 3 months of healing. Sections representing osteotome technique sites showed fractured trabeculae and large amounts of bone particles. CONCLUSIONS: It is suggested that immediate loading of implants does not influence the osseointegration process, whereas the density of newly formed peri-implant bone at such sites appears to be increased in relation to unloaded control implants. The use of an osteotome preparation technique during installation results in damage of peri-implant bone and enhances the risk for failure in osseointegration.

Are peri-implantitis lesions different from periodontitis lesions?

AIM: To compare histopathological characteristics of peri-implantitis and periodontitis lesions. METHODS: A search was conducted on publications up to July 2010. Studies carried out on human biopsy material and animal experiments were considered. RESULTS: While comprehensive information exists regarding histopathological characteristics of human periodontitis lesions, few studies evaluated peri-implantitis lesions in human biopsy material. Experimental peri-implantitis lesions were evaluated in 10 studies and three of the studies included comparisons to experimental periodontitis. Human biopsy material: the apical extension of the inflammatory cell infiltrate (ICT) was more pronounced in peri-implantitis than in periodontitis and was in most cases located apical of the pocket epithelium. Plasma cells and lymphocytes dominated among cells in both types of lesions, whereas neutrophil granulocytes and macrophages occurred in larger proportions in peri-implantitis. EXPERIMENTAL STUDIES: placement of ligatures together with plaque formation resulted in loss of supporting tissues and large ICTs around implants and teeth. Following ligature removal, a "self-limiting" process occurred in the tissues around teeth with a connective tissue capsule that separated the ICT from bone, while in peri-implant tissues the ICT extended to the bone crest. CONCLUSION: Despite similarities regarding clinical features and aetiology of peri-implantitis and periodontitis, critical histopathological differences exist between the two lesions.

B-1a cells in experimental gingivitis in humans.

BACKGROUND: Although previous studies revealed the presence of autoreactive B cells (B-1a cells) in periodontitis lesions, no evidence was provided for an active role of such cells in the host response to microbial challenge. The aim of the present investigation was to study the reaction of B-1a cells to de novo plaque formation in subjects who were treated for severe chronic periodontitis. METHODS: Fifteen white subjects with generalized, severe chronic periodontitis volunteered. Surgical periodontal therapy was performed in all quadrants of each subject after a period of infection control. After 6 months of healing (baseline), two gingival biopsies were harvested from each patient (probing depth <4 mm and no bleeding on probing; healed sites). The experimental gingivitis model was applied, and plaque accumulation was allowed for 3 weeks. Two additional biopsies were collected and prepared for immunohistochemical analysis on day 21. RESULTS: The biopsies retrieved after 3 weeks of plaque accumulation contained larger proportions of CD19+ and CD5+ cells (B-1a cells) than biopsies representing baseline (healed sites) (7.38% +/- 2.80% versus 5.96% +/- 2.48%). The tissue fraction of cells carrying the markers for CD3 (T cells), CD19 (B cells), and Bcl2 (apoptosis-associated marker) were significantly larger in tissue samples collected after 3 weeks of plaque accumulation than in specimens from baseline (healed sites). CONCLUSION: Autoreactive B cells (B-1a cells) are involved in the host response to microbial challenge in subjects with chronic periodontitis.

Local expression of interleukin-10 and mCD14 in relation to the -1087 IL-10 and -159 CD14 gene polymorphisms in chronic periodontitis.

BACKGROUND: Associations between different gene polymorphisms and severe chronic periodontitis have been demonstrated. However, the influence of such genetic variations on the production of related proteins needs to be clarified. The aim of the present investigation was to study the local expression of interleukin (IL)-10 and membrane-bound CD14 (mCD14) in relation to the -1087 IL-10 and -159 CD14 gene polymorphisms in subjects with chronic periodontitis. METHODS: Fifty-three white subjects with generalized and severe chronic periodontitis volunteered. Twenty milliliters of blood was collected by venipuncture from each subject. DNA was isolated, and genotype analysis of the -1087 IL-10 and -159 CD14 gene polymorphisms was performed using polymerase chain reaction and restriction endonuclease mapping techniques. A gingival biopsy from one randomly selected diseased proximal site was also obtained from each subject. The biopsies were embedded, snap frozen, and prepared for immunohistochemical analysis. The inflammatory lesion was identified in the sections, and the proportions of IL-10+ and CD14+ cells were determined. RESULTS: The proportion of IL-10+ cells in the peripheral area of the periodontitis lesions was significantly larger in subjects with the -1087 IL-10 GG genotype than in subjects with the AG or AA genotype. However, the local expression of the mCD14 receptor did not vary between subjects with different -159 CD14 genotypes. CONCLUSIONS: It is suggested that IL-10 expression in chronic periodontitis lesions is associated with a distinct genotype. The observation adds to our understanding of interactions between genetic and environmental factors in the development of human diseases.

Aspects of adaptive host response in periodontitis.

OBJECTIVE: To review host response in periodontitis with respect to cellular composition of lesions, T cell receptor (TCR) gene expression, cytokine profiles of T-helper (Th) cells and autoimmune components. MATERIAL AND METHODS: The studies included were confined to human material (biopsies, gingival crevicular fluid, blood from subjects with periodontitis). RESULTS AND CONCLUSIONS: In periodontitis lesions, plasma cells are the most common cell type and represent about 50% of all cells, while B cells comprise about 18%. The proportion of B cells is larger than that of T cells and Th cells occur in larger numbers than T cytotoxic cells. Polymorphonuclear cells and macrophages are found in fractions of less than 5% of all cells. Lesions in aggressive and chronic forms of periodontitis exhibit similar cellular composition. Differences in disease severity, however, may reflect increases in plasma cell and B cell densities. B cells serve as important antigen-presenting cells in periodontitis. The periodontitis lesion expresses a unique TCR gene repertoire that is different from that in blood. The role of superantigens in periodontitis is unclear. There are few studies using comparative designs and unbiased quantitative methods regarding Th-1 and Th-2 cells in periodontitis. The relative dominance of B cells and plasma cells in periodontitis lesions cannot entirely be explained by enhanced Th-2 functions but maybe because of an imbalance between Th-1 and Th-2. Autoimmune reactions are evident in periodontitis lesions. The role of auto-antibodies in the regulation of host response in periodontitis, however, needs to be clarified. Auto-reactive B cells occur in larger proportions in subjects with periodontitis than in healthy controls.

Association of the -159 CD14 gene polymorphism and lack of association of the -308 TNFA and Q551R IL-4RA polymorphisms with severe chronic periodontitis in Swedish Caucasians.

BACKGROUND: Severe forms of periodontitis are suggested to have a genetic basis. OBJECTIVE: The aim of the present investigation was to study the association of gene polymorphisms related to some immune regulation components (G-308A TNFA, Q551R IL-4RA and C-159T CD14) with severe chronic periodontitis. MATERIALS AND METHODS: Sixty patients (aged 36-74 years; mean 54.5+/-8.5) with severe and generalized chronic periodontitis were included. The patients exhibited bone loss >50% at all teeth. Thirty-nine periodontally healthy subjects between 35 and 78 years of age (mean 51.0+/-10.9) were recruited as controls. DNA was isolated from peripheral blood cells and genotyping was performed by combination of PCR and restriction endonuclease mapping. RESULTS: While gene polymorphisms for TNFA and IL-4RA did not show any association with severe chronic periodontitis, the analysis of the -159 CD14 gene polymorphism revealed significant differences between test and control groups. The proportion of subjects that exhibited the TT genotype was significantly smaller in the group with severe periodontitis than in periodontal healthy group (p=0.028; Fisher's exact test). The C allele carriage was 90% in the periodontitis group and significantly higher than in the healthy control group (72%). CONCLUSION: It is suggested that the -159 CD14 gene polymorphism is associated with chronic periodontitis in Caucasian subjects of a north European origin.

Association of the -1087 IL 10 gene polymorphism with severe chronic periodontitis in Swedish Caucasians.

BACKGROUND: Severe forms of periodontitis are suggested to have a genetic basis. OBJECTIVE: The aim of the present investigation was to study association of an IL10 gene polymorphism (G to A transition at the -1087 position) with severe chronic periodontitis. MATERIALS AND METHODS: Two groups of Swedish Caucasian subjects were included. One group consisted of 60 patients (aged 36-74 years; mean 54.5+/-8.5) with severe and generalized chronic periodontitis. The patients exhibited bone loss >50% at all teeth. Thirty-nine periodontally healthy subjects between 35-78 years of age (mean 51.0+/-10.9) were also recruited. DNA was isolated from peripheral blood cells and genotyping was performed by combination of PCR with restriction endonuclease mapping. RESULTS: The proportion of subjects that exhibited the GG genotype was significantly larger in the group with severe periodontitis than in the periodontally healthy group. The difference regarding the occurrence of the GG genotype between the two groups was more conspicuous in non-smokers and yielded an odds ratio of 6.1. The G allele carriage in non-smokers was >90 % in the periodontitis group and was significantly higher than in the healthy controls. CONCLUSION: It is suggested that the -1087 IL10 polymorphism in Caucasian subjects of a north European origin is associated with severe chronic periodontitis.