In vitro assessment of internal implant-abutment connections with different cone angles under static loading using synchrotron-based radiation.

BACKGROUND: The stability of implant-abutment connection is crucial to minimize mechanical and biological complications. Therefore, an assessment of the microgap behavior and abutment displacement in different implant-abutment designs was performed. METHODS: Four implant systems were tested, three with a conical implant-abutment connection based on friction fit and a cone angle < 12 ° (Medentika, Medentis, NobelActive) and a system with an angulated connection (< 40°) (Semados). In different static loading conditions (30 N - 90º, 100 N - 90º, 200 N - 30º) the microgap and abutment displacement was evaluated using synchrotron-based microtomography and phase-contrast radioscopy with numerical forward simulation of the optical Fresnel propagation yielding an accuracy down to 0.1 µm. RESULTS: Microgaps were present in all implant systems prior to loading (0.15-9 µm). Values increased with mounting force and angle up to 40.5 µm at an off axis loading of 100 N in a 90° angle. CONCLUSIONS: In contrast to the implant-abutment connection with a large cone angle (45°), the conical connections based on a friction fit (small cone angles with < 12°) demonstrated an abutment displacement which resulted in a deformation of the outer implant wall. The design of the implant-abutment connection seems to be crucial for the force distribution on the implant wall which might influence peri-implant bone stability.

Mass spectrometry-based proteomic applications in dental implants research.

Dental implants have been established as successful treatment options for missing teeth with steadily increasing demands. Today, the primary areas of research in dental implantology revolve around osseointegration, soft and hard tissue grafting as well as peri-implantitis diagnostics, prevention, and treatment. This review provides a comprehensive overview of the current literature on the application of MS-based proteomics in dental implant research, highlights how explorative proteomics provided insights into the biology of peri-implant soft and hard tissues and how proteomics facilitated the stratification between healthy and diseased implants, enabling the identification of potential new diagnostic markers. Additionally, this review illuminates technical aspects, and provides recommendations for future study designs based on the current evidence.

Root Coverage Using a Novel Porcine Acellular Dermal Matrix: Case Reports of Different Minimally Invasive Techniques with a 3-Year Follow-up.

A recently released commercially available novel porcine acellular dermal matrix (PADM) appears to possess acceptable biologic and clinical properties to be considered as an acceptable soft tissue replacement material. The aim of these three case reports is to present the treatment of multiple gingival recession by means of different variations of the tunnel and PADM as well as the clinical outcomes obtained at 3 years postoperatively. The healing outcomes demonstrated only minor surgical complications, with minimal patient-reported discomfort. At 3 years postoperative, ideal functional and esthetic outcomes were observed. PADM seems to be a promising xenogeneic soft tissue substitute. Further studies with a higher number of patients and defects are necessary to confirm the present findings.

Impact of peri-implantitis on the proteome biology of crevicular fluid: A pilot study.

BACKGROUND: The proteome of the peri-implant crevicular fluid (PICF) has not been systematically investigated. The aim of the present study was to reveal the proteome biology of dental implants affected with peri-implantitis. METHODS: Patients with at least one diseased implant were included (probing depth ≥6 mm, ≥3 mm peri-implant radiological bone loss). Using sterile paper strips, samples were collected from healthy implants (I), healthy teeth (T) and peri-implantitis affected implants (P). Proteome analysis was performed using liquid chromatography - tandem mass spectrometry (LC-MS/MS) and data independent acquisition, allowing the identification and quantification of human and bacterial proteins as well as semi-specific peptides. RESULTS: A total of 38 samples from 14 patients were included in the study; 2332 different human proteins were identified across all samples. No differentially expressed proteins between T and I were found. Comparing P to I, 59 proteins were found upregulated and 31 downregulated in P with significance. Upregulated proteins included proinflammatory proteins such as immunoglobulins, dysferlin, and S100P, as well as antimicrobial proteins, for example, myeloperoxidase or azurocidin. Gene ontology analysis further revealed higher activity of immunological pathways. Proteolytic patterns indicated the activity of inflammatory proteins such as cathepsin G. A total of 334 bacterial proteins were identified and quantified. Peri-implantitis showed elevated proteolytic activity. CONCLUSION: I and T share similarities in their proteome, while diseased implants deviate strongly from healthy conditions. The PICF proteome of peri-implantitis affected sites exhibits an inflammatory fingerprint, dominated by neutrophil activity when compared with healthy implants.

Association of sex steroid hormones and new bone formation rate after iliac onlay grafting: a prospective clinical pilot study.

PURPOSE: The present prospective study evaluates the association between new bone formation rate in the iliac onlay graft and sex steroid hormone serum levels. METHODS: A total of 15 partially or completely edentulous postmenopausal females and 9 males with less than 5 mm height of the remaining alveolar bone underwent iliac onlay grafting followed by dental implant placement using a two-stage approach. Sex hormone binding globulin and 17ß-estradiol serum levels were investigated by electrochemiluminescence immunoassay, while total testosterone level was analyzed using radioimmunoassay. At the time of implant placement, 12 weeks after grafting, bone biopsies were obtained and analyzed histomorphometrically. Statistical analysis was performed using linear mixed models. RESULTS: Grafting procedure was successfully performed in all patients. The mean new bone formation rate was 32.5% (116 samples). In men the mean new bone formation rate (38.1%) was significantly higher (p < 0.01) than in women (27.6%). Independent of gender 17ß-estradiol and testosterone were positively associated to overall new bone formation rate, albeit a significant influence was only seen for 17ß-estradiol in men (p = 0.020). Sex hormone binding globulin had no influence on new bone formation rate (p = 0.897). There was no significant association between new bone formation rate and age (p = 0.353) or new bone formation rate and body mass index (p = 0.248). CONCLUSION: Positive association of 17ß-estradiol as well as testosterone with new bone formation rate after iliac onlay grafting indicates a role of sex steroid hormones in alveolar bone regeneration, although the observed influence was only significant for 17ß-estradiol in men.

Comparison of the 3D-Microstructure Between Alveolar and Iliac Bone for Enhanced Bioinspired Bone Graft Substitutes.

In oral- and maxillofacial bone augmentation surgery, non-vascularized grafts from the iliac crest demonstrate better clinical performance than alveolar bone grafts. The underlying mechanisms are not fully understood but are essential for the enhancement of bone regeneration scaffolds. Synchrotron Radiation µ-CT at a pixel size of 2.3 µm was used to characterize the gross morphology and the vascular and osteocyte lacuna porosity of patient-matched iliac crest/alveolar bone samples. The results suggest a difference in the spatial distribution of the vascular pore system. Fluid simulations reveal the permeability tensor to be more homogeneous in the iliac crest, indicating a more unidirectional fluid flow in alveolar bone. The average distance between bone mineral and the closest vessel pore boundary was found to be higher in alveolar bone. At the same time, osteocyte lacunae density is higher in alveolar bone, potentially compensating for the longer average distance between the bone mineral and vessel pores. The present study comprehensively quantified and compared the 3D microarchitecture of intraindividual human alveolar and iliac bone. The identified difference in pore network architecture may allow a bone graft from the iliac crest to exhibit higher regeneration potential due to an increased capacity to connect with the surrounding pore network of the residual bone. The results may contribute to understanding the difference in clinical performance when used as bone grafts and are essential for optimization of future scaffold materials.

Effect of peri-implant mucosal thickness on esthetic outcomes and the efficacy of soft tissue augmentation procedures: Consensus report of group 2 of the SEPA/DGI/OF workshop.

OBJECTIVES: The aim of this study was to comprehensively assess the literature in terms of the effect of peri-implant mucosal thickness on esthetic outcomes and the efficacy of soft tissue augmentation procedures to increase the mucosal thickness with autogenous grafts or soft tissue substitutes. MATERIAL AND METHODS: Two systematic reviews (SR) were performed prior to the consensus meeting to assess the following questions. Review 1, focused question: In systemically healthy patients with an implant-supported fixed prosthesis, what is the influence of thin as compared to thick peri-implant mucosa on esthetic outcomes? Review 2, focused question 1: In systemically healthy humans with at least one dental implant (immediate or staged implant), what is the efficacy of connective tissue graft (CTG), as compared to absence of a soft tissue grafting procedure, in terms of gain in peri-implant soft tissue thickness (STT) reported by randomized controlled clinical trials (RCTs) or controlled clinical trials (CCTs)? Review 2, focused question 2: In systemically healthy humans with at least one dental implant (immediate or staged implant), what is the efficacy of CTG, as compared to soft tissue substitutes, in terms of gain in peri-implant STT reported by RCTs or CCTs? The outcomes of the two SRs, the consensus statements, the clinical implications, and the research recommendations were discussed and subsequently approved at the consensus meeting during the group and plenary sessions. CONCLUSIONS: There was a tendency of superior esthetic outcomes in the presence of a thick mucosa. The connective tissue graft remains the standard of care in terms of increasing mucosa thickness.

Cross-sectional evaluation of clinical and immunological parameters at partially microgrooved vs machined abutments in humans.

OBJECTIVE: The objective of the present study was to examine the clinical and immunological parameters in samples collected from the peri-implant crevicular fluid (PICF) of machined titanium (M) abutments compared to titanium abutments with a laser-microtextured surface (LMS) on dental implants. MATERIAL AND METHODS: A total of 40 patients with one titanium implant, half of them (n=20) provided with a M abutment (control group) and the other half (n=20) with LMS abutments (test group), were included in the study. Clinical parameters pocket probing depth (PD), full-mouth plaque score (FMPS), radiographic bone loss (RBL), clinical attachment level (CAL), mucosal recession (MR), bleeding on probing (BOP), and width of keratinized mucosa (KM) were evaluated. The peri-implant sulcus fluid was analyzed for cytokines IL-1α, IL-1ß, IL-6, IL-8, and IL-10 via flow cytometry. RESULTS: Clinical evaluation demonstrated no significant difference of PD (mean LMS = 3.50 mm/SD 0.95 mm vs mean M = 3.45 mm/SD 0.76 mm (p=0.855)), MR (mean LMS = 0.30 mm/SD 0.57 mm vs mean M = 0.35 mm/SD 0.67 mm (p=0.801)), CAL (mean LMS = 3.60 mm/SD 1.14 mm vs mean M = 3.55 mm/SD 0.89 mm (p=0.878)), and KM (mean LMS = 2.03 mm/SD 1.08 mm vs mean M = 2.13 mm/SD 0.92 mm (p=0.754)) between LMS and M abutments. LMS abutments showed less BOP than M abutments (26.7% vs 30.8%), but statistically not significant (p = 0.2235). Radiographic bone loss (mean LMS = 0.22 mm/SD 0.44 mm vs mean M = 0.59 mm/SD 0.49 mm) was reduced in the test group in comparison with the control group (p=0.016). In the collected PICF, the levels of pro-inflammatory cytokines IL-1α (median LMS = 180.8 pg/ml vs M = 200.9 pg/ml (p=0.968)) and IL-1ß (median LMS = 60.43 pg/ml vs M = 83.11 pg/ml (p=0.4777)) were lower, and the levels of IL-6 (median LMS = 180.8 pg/ml vs M = 200.9 pg/ml (p<0.0001)) were significantly lower in the test group. In contrast, the levels of IL-8 (median LMS = 255.7 pg/ml vs M = 178.7 pg/ml (p=0.3306)) were higher in the test group, though not significantly. The levels of anti-inflammatory IL-10 were significantly increased in the test group (LMS median = 0.555 pg/ml vs M median = 0.465 pg/ml (p=0.0365)). IL-1ß showed a significant correlation to radiologic bone loss (p=0.0024). The other variables IL-1α, IL-6, IL-8, and IL-10 had no significant correlation to radiological bone loss. CONCLUSION: Within the limitations of this study, titanium implants provided with laser-microtextured surface abutments seem to demonstrate less pro-inflammatory and more anti-inflammatory activity and to show reduced radiographic bone loss compared to machined titanium abutments. CLINICAL RELEVANCE: The use of laser-microtextured surface abutments might have the potential to support peri-implant tissue health.

Immunohistological composition of peri-implantitis affected tissue around ceramic implants-A pilot study.

BACKGROUND: Aim of the pilot study was the histologic classification of the inflamed peri-implant soft tissue around ceramic implants (CI) in comparison with titanium implants (TI). METHODS: Peri-implant tissue were retrieved from 15 patients (aged 34 to 88 years, seven males/eight females) with severe peri-implantitis (eight CI, seven TI). The peri-implant soft tissue samples were retrieved from the sites during scheduled removal of the implant and prepared for immunohistochemical analysis. Monoclonal antibodies (targeting CD3, CD20, CD138, and CD68) were used to identify T- and B-cells, plasma cells and macrophages. Quantitative assessment was performed by one histologically trained investigator. Linear mixed regression models were used. RESULTS: A similar numerical distribution of the cell population was found in peri-implantitis around CI compared with TI. CD3 (TI, 17% to 85% versus CI, 20% to 70% of total cell number) and CD138 (TI, 1% to 73% versus CI, 12% to 69% of total cell number) were predominantly expressed. Notably, patient-individual differences of numerical cell distribution were detected. Co-localization of B- and T-lymphocytes was observed. CONCLUSIONS: Peri-implantitis around CI in comparison with TI seems to have a similar histological appearance. Differences in cellular composition of peri-implantitis lesions might also depend on the patient's specific immune status and not only on the material used.

Implant success and survival rates in daily dental practice: 5-year results of a non-interventional study using CAMLOG SCREW-LINE implants with or without platform-switching abutments.

BACKGROUND: The performance of dental implants in controlled clinical studies is often investigated in homogenous populations. Observational studies are necessary to evaluate the outcome of implant restorations placed in real-life situations, according to standard practice, and to assess the needs of the patients. The aim of this non-interventional study was to reveal the survival, success, and general performance of CAMLOG SCREW-LINE implants and their restorations in daily dental practice. METHODS: Seventeen private practices across five countries participated in this prospective multicenter study. Patients received implants in the maxilla and mandible which were restored either with platform-matching or platform-switching abutments. Patients were followed-up for up to 5 years post-loading. Radiographs and clinical parameters were evaluated and patient satisfaction was evaluated. RESULTS: From a total of 196 patients planned, 185 patients with 271 implants were restored with abutments and fulfilled the follow-up inclusion criteria. Three implant failures were recorded, resulting in a cumulative survival rate of 98.6% after 5 years post-loading. One persistent complication of peri-implantitis occurred. The soft tissue health remained stable, and the papilla height improved after loading. At 5-year follow-up, the mean crestal bone loss was - 0.28 ± 0.60 mm; over 99% of patients reported satisfaction with the restoration as excellent or good. CONCLUSIONS: Implants placed and restored with both platform-matching and platform-switching abutments in daily dental private practice achieved excellent clinical outcomes with highly satisfied patients after 5 years of function, confirming the results obtained in well-controlled clinical trials.

Influence of the width of keratinized tissue on the development and resolution of experimental peri-implant mucositis lesions in humans.

OBJECTIVES: To analyze the influence of the width of keratinized mucosa (KM) on the development and resolution of experimental peri-implant mucositis lesions at abutments with different microstructures in humans. MATERIAL AND METHODS: In a randomized, controlled study, a total of 28 patients had received 28 target implants exhibiting a KM ≥2 mm. These were randomly connected with either partially microgrooved- (test) (n = 15) or machined (control) (n = 13) healing abutments. The study protocol included a wound healing period (WH) following implant placement (12 weeks), a plaque exposure phase (EP) of 21 days (EPd21) and a resolution phase (RP) including visits at 2, 4, and 16 weeks (RPw2; RPw4; RPw16) following plaque removal. Linear regression analyses were used to analyze the relationship between the width of KM and clinical outcomes (i.e., modified plaque index [mPI], modified gingival index [mGI], bleeding on probing [BOP], and probing depth [PD]). RESULTS: Mean and median KM values (end of WH) were 5.9 ± 2.6 and 5.0 mm (min: 2 mm; max: 10 mm; interquartile range: 5 mm) at test- and 5.5 ± 2.6 and 4.0 mm (min: 3 mm; max: 11 mm interquartile range: 4 mm) at control abutments. The linear regression analysis revealed significant correlations between the width of KM and mPI (test: RPw2; control: RPw16), mGI (test: RPw16), BOP (both: RPw16), and PD (test: RPw16; control: EPd21, RPw2, RPw4, RPw16) scores. CONCLUSION: The width of KM (≥2 mm) had some effects on the development (i.e., at 21 days) and resolution of experimental peri-implant mucositis lesions at both abutment types.

Onset, progression and resolution of experimental peri-implant mucositis at different abutment surfaces: A randomized controlled two-centre study.

OBJECTIVES: To assess the onset, progression and resolution of experimentally induced peri-implant mucositis lesions at abutments with different microstructures in humans. MATERIAL & METHODS: In a randomized, controlled, interventional two-centre study, a total of 28 patients had received 28 target implants and were randomly allocated to either partially microgrooved (test) or machined (control) healing abutments. The study was accomplished in three phases, including a wound healing period (WH) following implant placement (12 weeks), a plaque exposure phase (EP-21 days) and a resolution phase (RP-16 weeks). Clinical (e.g. bleeding on probing-BOP), immunological (MMP-8) and microbiological (DNA counts for 11 species) parameters were evaluated. RESULTS: The incidence of peri-implant mucositis at EPd21 was comparable in both test and control groups (60.0% versus 61.5%), but markedly lower at control abutments after a nonsurgical treatment and reconstitution of oral hygiene measures at RPw16 (46.7% versus 15.4%). At any follow-up visit (i.e. EP and RP), clinical parameters, MMP-8 levels and DNA counts of major bacterial species were not significantly different between both groups. CONCLUSION: The onset, progression and resolution of experimental peri-implant mucositis lesions were comparable in both groups.

Horizontal mucosal thickness at implant sites as it correlates with the integrity and thickness of the buccal bone plate.

OBJECTIVES: To histologically assess the association between the horizontal mucosal thickness (MT) at implant sites with the integrity and thickness of the buccal bone plate in a canine model. MATERIALS AND METHODS: Two-piece titanium implants were placed at chronic-type lateral ridge defects. The resulting vestibular dehiscence-type defects (vertical dimensions of 2-8 mm) were left untreated. After a submerged healing period of 2 and 8 weeks (n = 6 fox hounds each), dissected blocks were processed for histomorphometrical analyses [e.g. MT, bone thickness (BT) and residual defect length]. RESULTS: Linear regression revealed significant associations between vestibular MT and BT values after 2 (R2  = 0.22, B = -0.37, P < 0.0001) and 8 weeks (R2  = 0.37, B = -0.45, P < 0.001) of healing. CONCLUSION: The present analysis has pointed to an inverse relationship between horizontal MT and BT values at the vestibular aspect of submerged titanium implants. MT was most pronounced in the absence of a buccal bone plate.

Healing of localized gingival recessions treated with coronally advanced flap alone or combined with either a resorbable collagen matrix or subepithelial connective tissue graft. A preclinical study.

OBJECTIVES: To histologically evaluate the effectiveness of a porcine derived collagen matrix (CM) and a subepithelial connective tissue graft (CTG) for coverage of localized gingival recessions. MATERIALS AND METHODS: Chronic single Miller Class I-like recessions were created at the buccal at the canines and at the third and fourth premolars in the upper and lower jaws of six beagle dogs. The defects were randomly treated with (1) coronally advanced flap surgery (CAF) + CM, (2) CAF + CTG, or (3) CAF alone. At 12 weeks, histometric measurements were made, e.g., between a reference point (N) - and the gingival margin (GM) - and the outer contour of the adjacent soft tissue (gingival thickness [GT]). RESULTS: The postoperative healing was uneventful in all animals. No complications such as allergic reactions, abscesses or infections were noted throughout the entire study period. All three treatments resulted in coverage of localized gingival recessions. The histological analysis failed to identify any residues of CM or CTG. The histometric measurements revealed comparable outcomes for N-GM and GT values for all three groups (CAF + CM: 1.04 ± 0.69 mm/0.68 ± 0.33 mm; CAF + CTG: 1.15 ± 1.12 mm/0.76 ± 0.37 mm; CAF: 1.43 ± 0.45 mm/0.79 ± 0.24 mm). CONCLUSIONS: In the used defect model, the application of CTG or CM in conjunction with CAF did not have an advantage over the use of CAF alone. CLINICAL RELEVANCE: The use of CAF alone is a valuable option for the treatment localized Miller Class I recessions.

Epithelial attachment and downgrowth on dental implant abutments--a comprehensive review.

UNLABELLED: The soft tissues around dental implants are enlarged compared with the gingiva because of the longer junctional epithelium and the hemidesmosonal attachments are fewer, suggestive of a poorer quality attachment. Inflammatory infiltrates caused by bacterial colonization of the implant-abutment interface are thought to be one of the factors causing epithelial downgrowth and subsequent peri-implant bone loss. Gold alloys and dental ceramics as well as the contamination of the implant surface with amino alcohols, appear to promote epithelial downgrowth. Physical manipulaton of the abutment surfaces, including concave abutment designs, platform switching, and microgrooved surfaces are believed to inhibit epithelial downgrowth and minimizes bone loss at the implant shoulder. This paper reviews the factors that are believed to influence the migration of epithelial attachment the dental implant and abutment surfaces. Exploration of innovative computer-aided design/computer-aided manufacturing-based concepts such as "one abutment-one time" and their effect on epithelial downgrowth are discussed. CLINICAL SIGNIFICANCE: Based on the review of current literature, the authors recommend inserting definitive abutments at the time of surgical uncovering. To implement this concept, registration of the implant position should to be taken at the time of surgical implant placement.

Shell technique using a rigid resorbable barrier system for localized alveolar ridge augmentation.

OBJECTIVES: To assess the safety and efficacy of a rigid synthetic barrier system in a shell technique for localized alveolar ridge augmentation. MATERIALS AND METHODS: Saddle-type defects (n = 4 each) were prepared in the lower jaws of six fox hounds. At two defects, the outer contours were reconstructed using polylactic acid (D and L isomers) (PDDL) pins welded to PDDL plates by ultrasound vibration and the defect area filled using either a natural bone mineral (NBM) or NBM + autogenous bone (AB) and covered by a native collagen membrane (CM). While the third defect was augmented using NBM+AB+CM, the fourth site was left untreated. At 14 weeks, dissected blocks were processed for histomorphometrical analysis [e.g., augmented area (AA)]. RESULTS: AA values (median in mm(2)) were significantly increased in all guided bone regeneration (GBR) groups [NBM+PDDL+CM (19.74) > NBM+AB+PDDL+CM (16.98) > NBM+AB+CM (16.66)] when compared with the untreated control sites (7.34). Histological analysis has pointed, in the absence of any foreign-body reactions, to biodegradation of both PDDL plates/pins and CM. CONCLUSIONS: (i) All GBR procedures investigated equally supported bone regeneration, (ii) the application of PDDL+CM may be associated with increased mineralized tissue MT and subsequently AA values than CM alone, and (iii) AB may not improve healing at NBM+PDDL+CM-treated sites.

Use of a self-curing resorbable polymer in vertical ridge augmentations - a pilot study in dogs.

AIM: The aim of the present study was to evaluate bone formation in vertical ridge augmentations using particulate bone grafting material stabilized by a resorbable polymer. MATERIAL AND METHODS: Three vertical defects were created in the maxillary alveolar ridge of six Beagle dogs 3 months after the removal of all premolars. One defect in each dog was filled with tricalciumphosphate/hydroxylapatite (TCP/HA) grafting material and stabilized using a poloxamer hydrogel (test group). Defects filled with grafting material only and covered with a collagen membrane as well as empty defects served as controls (controls 1 & 2). Bone formation in the defects was evaluated after 14 weeks of healing using histomorphometry on undecalcified thick-section specimens. RESULTS: There was no difference between the test group and the controls with respect to the amount of newly formed bone, percentage of bone fill, and bone density. The mean maximum bone height within the augmented area was the only parameter that was significantly higher in the test group compared with empty defects. The use of the poloxamer gel did not result in a better preservation of ridge shape compared with the group of augmentations covered with a collagen membrane. CONCLUSIONS: The use of a poloxamer gel for the stabilization of particulate bone grafting material in vertical ridge augmentations had no advantage compared with coverage of grafting materials with a collagen membrane.

Allergy or tolerance: reduced inflammatory cytokine response and concomitant IL-10 production of lymphocytes and monocytes in symptom-free titanium dental implant patients.

Hypersensitivity reactions to titanium (Ti) are very rare. Thus, we assessed the proinflammatory response and also potential tolerance favoring in vitro reactivity of human blood lymphocytes and monocytes (PBMC) to Ti in healthy individuals (14 without, 6 with complication-free dental Ti implants). The proliferation index (SI) in lymphocyte transformation test (LTT) and production of cytokines linked to innate immune response (IL-1 ß , IL-6, and TNF α ) or immune regulation (IL-10) were assessed in response to TiO2 particles or Ti discs. In both groups, the Ti-LTT reactivity was not enhanced (e.g., SI < 3). The control antigen tetanus toxoid (TT) gave adequate reactivity (median SI individuals without/with implant: 20.6 ± 5.97/19.58 ± 2.99). Individuals without implant showed higher cytokine response to Ti materials than individuals with symptom-free implants; for example, TiO2 rutile particle induced increase of IL-1 ß 70.27-fold/8.49-fold versus control medium culture. PBMC of 5 of the 6 individuals with complication-free Ti implants showed an ex vivo ongoing production of IL-10 (mean 4.18 ± 2.98 pg/mL)-but none of the 14 controls showed such IL-10 production. Thus in vitro IL-1 ß -, IL-6-, and TNF- α production reflects "normal" unspecific immune response to Ti. This might be reduced by production of tolerogenic IL-10 in individuals with symptom-free Ti dental implants.

The impact of dis-/reconnection of laser microgrooved and machined implant abutments on soft- and hard-tissue healing.

OBJECTIVES: To (i) investigate the influence of different extensions of a laser microgrooved abutment zone on connective tissue attachment and (ii) assess the impact of a repeated abutment dis-/reconnection on soft- and hard-tissue healing. MATERIALS AND METHODS: Titanium implants were inserted epicrestally in the lower jaws of six dogs. Healing abutments with either partially (LP) or completely (LC) laser microgrooved margins or machined surface margins (M) were randomly allocated either to a single (1×)/repeated (2×) dis-/reconnection at 4 and 6 weeks (test), respectively, or left undisturbed (control). At 6 and 8 weeks, histomorphometrical (e.g. most coronal level of bone in contact with the implant [CBI], subepithelial connective tissue attachment [STC]) and immunohistochemical (Collagen Type-I [CI]) parameters were assessed. RESULTS: At control sites, LP/LC groups revealed lower mean CBL (8 weeks, 0.95 ± 0.51 vs. 0.54 ± 0.63 vs. 1.66 ± 1.26 mm), higher mean STC (8 weeks, 82.58 ± 24.32% vs. 96.37 ± 5.12% vs. 54.17 ± 8.09%), but comparable CI antigen reactivity. A repeated abutment manipulation was associated with increased mean CBL (8 weeks, 1.53 ± 1.09 vs. 0.94 ± 0.17 vs. 1.06 ± 0.34 mm), decreased STC (8 weeks, 57.34 ± 43.06% vs. 13.26 ± 19.04% vs. 37.76 ± 37.08%) and CI values. CONCLUSIONS: It was concluded that (i) LC>LP abutments enhanced subepithelial connective tissue attachment and preserved crestal bone levels, (ii) repeated abutment dis-/reconnection during the initial healing phase (4-6 weeks) may be associated with increased soft- and hard-tissue changes and (iii) LP and LC should be considered using a one abutment, one time approach.

Quality assessment of reporting of animal studies on pathogenesis and treatment of peri-implant mucositis and peri-implantitis. A systematic review using the ARRIVE guidelines.

OBJECTIVES: To address the following focused question: What is the quality of reporting of pre-clinical research for the study and treatment of mucositis/peri-implantitis? MATERIALS AND METHODS: Electronic databases of the PubMed and the Cochrane Library were searched for animal studies reporting on pathogenesis or therapy of either peri-implant mucositits or peri-implantitis and completed by dual manual searches in duplicate between 1992 and May 2011. Quality assessment (i.e. grading of a checklist of 20 items in different categories) of selected full-text articles was performed according to the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines. RESULTS: Following screening, 75 publications were eligible for the review. For publications reporting on pathogenesis (n = 7) and therapy (n = 1) of peri-implant mucositis, minimum gradings were assigned to items 5 (Methods/Ethical Statement), 9 (Methods/Housing and husbandry), 11 (Methods/Allocation animals to experimental groups), 14 (Results/Baseline data), and 17 (Results/Adverse events). For publications reporting on pathogenesis (n = 34) and therapy (n = 33) of peri-implantitis, minimum grades were mainly assigned to items 9, 11, 14, and 17. CONCLUSIONS: This systematic review has identified missing information in the publications on pre-clinical research for the study and treatment of mucositis/peri-implantitis.