Clinical, microbiological and osteoimmunological findings in different peri-implant conditions - A cross-sectional study.

OBJECTIVES: The aim of this study was to assess the prevalence of certain microbiota and their potential correlation with clinical parameters, expression of proinflammatory cytokines, Notch signalling pathway molecules and bone remodelling mediators among different peri-implant conditions. MATERIALS AND METHODS: Included participants had at least one dental implant minimally 1 year in function. They were divided into peri-implantitis (PI), peri-implant mucositis (PM) and healthy implants (HIs) groups. Prevalence of P. ginigvalis, Fusobacterium spp., EBV and C. albicans was detected in participants' crevicular fluid (CF) using quantitative real-time polymerase chain reaction, different markers' expression, as well as clinical data, were correlated with the microbial presence. RESULTS: CF samples taken from one chosen implant from each of the 102 participants were analyzed. Significantly higher levels of P. gingivalis were found in PI compared with HI (p = .012) and PM (p = .026). Fusobacterium spp. was also more prevalent in PI (p = .041) and PM (0.008) than in HI. P. gingivalis was a predictor of PPDi (p = .011, R2 = 0.063) and CALi (p = .049, R2 = 0.038). A positive correlation was found in PI for the level of Fusobacterium spp. and TNFα expression (ρ = 0.419, p = .017) while in PM, P. gingivalis and Notch 2 expression were correlated (ρ = 0.316, p = .047). CONCLUSIONS: P. gingivalis appears to be involved in the osteolysis in patients with PI, while the positive correlation of its level with Notch 2 expression in patients with PM suggests a potential involvement of P. gingivalis in the progression of PM into PI.

Involvement of the Notch signaling system in alveolar bone resorption.

The Notch pathway is an evolutionarily preserved signaling pathway involved in a variety of vital cell functions. Additionally, it is one of the key regulators of inflammation, and controls the differentiation and function of different cells. Moreover, it was found to be involved in skeletal development and bone remodeling process. This review provides an overview of the involvement of the Notch signaling pathway in the pathogenesis of alveolar bone resorption in different forms of pathological conditions such as apical periodontitis, periodontal disease, and peri-implantitis. In vitro and in vivo evidence have confirmed the involvement of Notch signaling in alveolar bone homeostasis. Nonetheless, Notch signaling system, along with complex network of different biomolecules are involved in pathological process of bone resorption in apical periodontitis, periodontitis, and peri-implantitis. In this regard, there is a substantial interest to control the activity of this pathway in the treatment of disorders associated with its dysregulation. This review provides knowledge on Notch signaling and outlines its functions in alveolar bone homeostasis and alveolar bone resorption. Further investigations are needed to determine whether inhibition of the Notch signaling pathways might be beneficial and safe as a novel approach in the treatment of these pathological conditions.

Notch signalling cascade and proinflammatory mediators in peri-implant lesions with different RANKL/OPG ratios-An observational study.

BACKGROUND & OBJECTIVE: Notch signaling pathway has been linked to bone loss in periodontitis and peri-implantitis. This research aimed to determine the Notch signaling molecules expression levels (Notch1, Notch2, Jagged1, Hes1, and Hey1), along with bone remodeling mediators (RANKL and OPG) and proinflammatory cytokines (TNF-α, IL-17, IL-1ß, and IL-6) in patients with peri-implant diseases. The aforementioned markers' expression was evaluated in patients with different RANKL/OPG ratios. METHODS: Fifty patients with peri-implantitis (PI group) and 45 patients with peri-implant mucositis (PM group) were enrolled. Relative gene expression levels of investigated molecules were determined by reverse transcriptase-real-time polymerase chain reaction. On the basis of RANKL/OPG ratio, all peri-implant lesions were divided into subgroups: RANKL-predominant (RANKL > OPG) and OPG-predominant (RANKL < OPG). Clinical periodontal parameters (probing depth-PD, bleeding on probing-BOP, clinical attachment level-CAL and plaque index-PLI), were recorded for each patient around every tooth, and around placed implants (PDi, BOPi, CALi, PLIi). RESULTS: RANKL-predominant PM patients exhibited higher expression levels of Notch2 (p = .044) and Hey1 (p = .005) compared to OPG-predominant lesions. In all RANKL-predominant cases, Hey1 (p = .001), IL-1ß (p = .005), IL-6 (p = .002) were overexpressed in PI comparing to PM, accompanied with significantly higher PDi, CALi and PLIi in PI than PM (p = .001, p = .001 and p = .009). CONCLUSIONS: Notch2 upregulation in RANKL-predominant PM lesions could be an important contributor to alveolar bone resorption and represent a predictor of PM to PI transition. Similarly, the overexpression of IL-1ß and IL-6 might provide an osteoclastogenic environment in PI RANKL-predominant lesions.

Immunohistochemical analysis of soft tissue response to polyetheretherketone (PEEK) and titanium healing abutments on dental implants: a randomized pilot clinical study.

BACKGROUND: The data on polyetheretherketone (PEEK) influence on the peri-implant soft tissues in clinical settings are deficient. The aims of this pilot study were to analyze and compare soft tissues' response to PEEK and titanium (Ti) healing abutments (HA) by means of histological and immunohistochemical analyses. METHODS: A total of 22 implants with PEEK or Ti HA were placed in 11 patients, applying the "split-mouth" study design. Three months later, soft tissue specimens were harvested from 20 implants for histology in order to qualitatively detect the inflammatory cells' presence, to semi-qualitatively analyze the inflammation intensity and to assess the inflammatory responses type by immunohistochemical analysis using LCA, CD3, CD20 and CD68 antibodies. RESULTS: Epithelial infiltrate followed by an intensive inflammation in sub-epithelium was observed in 100% around PEEK HA. A number of LCA+ and CD 68+ cells was significantly higher in PEEK comparing to Ti group (p = 0.001 and p = 0.020, respectively), while CD 20+ and CD3+ counted cells were found in a significantly higher amount in Ti than in PEEK group (p = 0.006 and p = 0.010, respectively). CONCLUSION: PEEK HA seems to evoke the more intense tissue inflammatory response demonstrated predominantly by histocytes' and plasmacytes' activation, while Ti HA triggers the inflammatory reaction of lower intensity, dominantly mediated by B-cells. TRIAL REGISTRATION: The study registered at ClinicalTrials.gov (NCT04436939).

Porphyromonas Gingivalis in Different Peri-Implant Conditions: a Pilot Cross - Sectional Study.

Objective: To assess the potential correlation between clinical peri-implant parameters and the presence of Porphyromonas gingivalis in different peri-implant conditions. Material and methods: The study included 30 patients from the Department of Periodontology and Oral Medicine divided into three equal groups, defined according to the following diagnoses: peri-implantitis (PI), peri-implant mucositis (PM), and peri-implant health (HI). Clinical parameters such as peri-implant probing depth (PPD), bleeding on probing (BOP), suppuration on probing (SUP), and plaque index (PI) were recorded. The samples of peri-implant crevicular fluid were collected and relative levels of Porphyromonas gingivalis were analyzed using Real-Time PCR (Reverse transcriptase - real-time polymerase chain reaction). Results: The mean patient age was 51.33 ± 12.61 years. The mean value for Porphyromonas ginigvalis relative level was higher in the PI group (14.80 ±31.51) compared to PM and HI group (0.48 ± 1.34 and 0.06 ± 0.12, respectively). This parameter significantly differed between PI and HI (p=0.012), as well as PI and PM (p=0.049). The mean whole mouth probing pocket depth (PPD) in the PI group (4.02mm ± 0.77mm) was also significantly greater compared to the other two groups (3.39mm ± 0.52mm in PM and 1.97mm ± 0.54mm in the HI group. The SUP in the PI (mean value of 18%) group was more frequent than in PM (mean value of 14%) while the SUP was not detected in the HI group. The correlation between clinical parameters and relative levels of Porphyromonas gingivalis was not significant. Conclusions: The findings of this research indicate higher relative levels of Porphyromonas gingivalis in peri-implant lesions, especially in peri-implantitis.

Notch down-regulation and inflammatory cytokines and RANKL overexpression involvement in peri-implant mucositis and peri-implantitis: A cross-sectional study.

OBJECTIVES: Notch signaling pathway, known to influence bone resorption in several oral diseases, has not been analyzed in peri-implantitis yet. Therefore, the aims of the present study were to determine the levels of Notch cascade, bone remodeling mediators, and pro-inflammatory cytokines, in conjunction with clinical parameters, in subjects with peri-implant mucositis and peri-implantitis. MATERIAL AND METHODS: Clinical parameters: peri-implant probing depth, bleeding on probing, suppuration on probing, and plaque index (PI) were recorded. Samples were collected from 130 participants, divided into peri-implantitis (PI), peri-implant mucositis (PM), and healthy implants (HI) group. Relative expression levels (REL) of Notch 1, Notch 2, Jagged 1, Hes 1, Hey 1, TNF-α, IL-17, IL-1ß, IL-6, RANKL, and OPG mRNA were determined by reverse transcriptase-real-time polymerase chain reaction. Quantitation of Notch 1, Il-17, and IL-6 proteins was performed using ELISA assays. RESULTS: All clinical parameters were significantly higher in PI compared to HI. Significant decrease of Notch 1, and higher REL of Hey 1, IL-1ß, IL-6, and RANKL were found in PI compared to HI. PM showed significant increase of IL-1ß REL in comparison with HI. In PI versus PM, significantly higher REL was found for Hey 1, TNF-α, IL-17, IL-1ß, IL-6, and RANKL. Additionally, higher protein concentrations of IL-6 and IL-17 were detected in PI versus PM and versus HI group. CONCLUSION: The combined effect of Notch 1 down-regulation and elevated expression of some key inflammation modulators might result in osteoclast activity increase and subsequent osteolysis in peri-implantitis.

Fabrication, workflow and delivery of reconstruction: Summary and consensus statements of group 4. The 6th EAO Consensus Conference 2021.

OBJECTIVES: To report assessments of four systematic reviews (SRs) on (i) clinical outcomes of all-ceramic implant-supported crowns (iSCs), (ii) production time, effectiveness, and costs of computer-assisted manufacturing (CAM), (iii) computer-assisted implant planning and surgery (CAIPS) time and costs, and (iv) patient-reported outcome measures (PROMS). MATERIAL AND METHODS: An author group consisting of experienced clinicians and content experts discussed and evaluated the SRs and formulated consensus on the main findings, statements, clinical recommendations, and need for future research. RESULTS: All four SRs were conducted and reported according to PRISMA and detailed comprehensive search strategies in at least three bibliometric databases and hand searching. The search strategies were deemed reproducible. Variation was noted regarding language restrictions and inclusion of grey literature, but the search comprehensiveness appeared persuasive. The SRs included bias risk assessments of the primary studies, and their study methodology impacted the interpretations of the extracted data. CONCLUSIONS: (i) There is limited evidence (49 NRCT) showing that veneered and monolithic all-ceramic iSCs have excellent outcomes observed up to 3 years. (ii) There is no evidence evaluating production time and effectiveness comparing subtractive and additive CAM of implant models, abutments and crowns. (iii) There is limited evidence (4 RCT) that CAIPS involves more time and costs when considering the entire workflow and for diagnostics, manufacturing, and insertion of the restoration. Time seems to be the decisive factor for higher costs. (iv) Patients' comfort increases when optical compared to conventional impressions are used for fabricating iSCs and short-span FPDs (2 RCT, 5 NRCT).

Impact of Notch signalling molecules and bone resorption regulators on clinical parameters in periodontitis.

BACKGROUND AND OBJECTIVE: Notch signalling cascade has recently been connected to alveolar bone resorption in periodontitis. Hence, the present cross-sectional study aimed to analyze the expression of Notch signalling pathway (Notch 1, Notch 2, Jagged 1, Hes 1, Hey 1) and periodontitis-related (tumor necrosis factor alpha- TNF-α, interleukin 17-IL-17, receptor activator of nuclear factor-kappa B ligand-RANKL, osteoprotegerin-OPG) molecules and correlate it with clinical parameters in aggressive (AP) and chronic (CP) periodontitis. Additionally, the aforementioned markers' expression was evaluated in periodontitis patients with different RANKL/OPG ratios. MATERIAL AND METHODS: Eighty patients were enrolled either in AP or CP group. Clinical attachment level (CAL), bleeding on probing (BOP), periodontal probing depth (PPD) and plaque index (PI) were recorded for each patient. Total RNA was extracted from gingival crevicular fluid samples. Relative gene expression of investigated markers was determined by reverse transcriptase-real-time polymerase chain reaction. RESULTS: Significantly higher values of PPD were observed in AP compared to CP (P = .010). Negative correlations between OPG and CAL, and OPG and PI, were found in AP (P = .045, P = .006, respectively), while Hey 1 and PI had a positive correlation (P = .049). In multivariate linear regression analysis, OPG and Notch 2 were predictors of CAL in AP group. TNF-α and IL-17 were higher in RANKL predominant than in OPG predominant cases (P = .007, P = .001, respectively). In RANKL predominant lesions Notch 1 and Jagged 1 were down-regulated in AP compared to CP patients (P = .010, P = .025, respectively). CONCLUSION: The present study demonstrated that changes in Notch 2 expression affected CAL in AP cases hence this molecule could be considered as a contributor to alveolar bone loss. In RANKL-activated settings, the down-regulation of Notch 1 might participate in more severe bone resorption in AP.

The use of collagen porcine dermal matrix and connective tissue graft with modified coronally advanced tunnel technique in the treatment of multiple adjacent type I gingival recessions: A randomized, controlled clinical trial.

OBJECTIVE: To assess the clinical efficacy and esthetic outcome of porcine-derived dermal collagen matrix in comparison with connective tissue graft in the treatment of multiple adjacent gingival recessions (MAGR), 6 and 12 months after the surgery. MATERIALS AND METHODS: Twenty patients with bilateral type I MAGR were treated randomly with porcine-derived dermal collagen matrix (test site) or connective tissue graft (control site) in combination with a modified coronally advanced tunnel technique. The primary objectives were to evaluate the mean and complete root coverage. The secondary objectives were to assess keratinized tissue width, gingival thickness gain, and root coverage esthetic score. RESULTS: Six and 12 months postoperatively, both groups achieved significant improvements in all clinical parameters compared to baseline, with no statistically significant differences between the groups. Mean root coverage change (Δ12m - 6 m) was statistically significant between the groups in favor of connective tissue graft, and twice as many patients exhibited a complete coverage of all recessions in the control group than the test group. CONCLUSION: The porcine-derived dermal collagen matrix combined with a modified coronally advanced tunnel technique resulted in satisfactory clinical and esthetic outcomes, which were similar to connective tissue graft. CLINICAL SIGNIFICANCE: Porcine-derived dermal collagen matrix (XDM) may be proposed as a substitute for connective tissue graft in multiple adjacent recession treatment due to successful root coverage, a significant increase of gingival thickness, and high esthetic outcomes. The clinical benefits for the use of XDM could be: (a) second surgical wound avoidance, (b) patient discomfort decrease, and (c) lower complications' rate.

The Why, What, How and What if-The method to present your research and clinical cases.

BACKGROUND: During the fourth Summer Camp (SC) held by the European Association of Osseointegration (EAO), 20 junior representatives from various European and non-European universities and associations were selected to partake in oral presentation and communication skill development. AIMS: The aim of the EAO Summer Camp (EAO SC) was to identify new methods of enhancing participants' abilities to engage, influence and lead in a professional environment, on both a clinical and scientific level. MATERIALS AND METHODS: Four different groups were assigned to discuss one of two topics: (1) an Implant Register and (2) Digital Dentistry. The method that was used during the EAO SC, for training presentation skills, was the 4MAT learning model. The 4MAT learning model is a framework for creating an engaged, dynamic and more involved style of training by accurately visualizing the learning process that each learner goes through. RESULTS AND CONCLUSIONS: All four groups, including each participant, presented outcomes in the format of 4MAT learning model answering four key questions, the Why, the What, the How and the What if. After the event, each group prepared a written summary of the thought processes. The outcome of the summer camp, for the chosen participants, was gaining skills to engage and influence in a professional environment, both clinically and scientifically. It was also expected from participants to share gained knowledge in their own respective environments after the EAO Summer Camp had ended. In conclusion, most of participants gained a valuable insight into presentation skills and also demonstrated their enthusiasm by presenting their experience at universities, institutes and clinics.

The down-regulation of Notch 1 signaling contributes to the severity of bone loss in aggressive periodontitis.

BACKGROUND: The exact mechanisms of bone resorption in periodontitis have not been fully elucidated. The aims of this study were to analyze the expression of Notch signaling molecules, bone remodeling mediators, and pro-inflammatory cytokines in periodontitis patients and to determine their potential correlations. METHODS: The study included 130 individuals: 40 with aggressive periodontitis (AP group), 40 with chronic periodontitis (CP group), and 50 periodontally healthy controls. Total RNA was extracted from gingival crevicular fluid samples and relative gene expression of investigated molecules (Notch 1, Notch 2, Jagged 1, Hes 1, Hey 1, TNF-α, IL-17, RANKL, and OPG) was determined by reverse transcriptase - real-time polymerase chain reaction (RT-qPCR). RESULTS: In AP group, a significant increase of Notch 2, TNF-α, IL-17 and RANKL and a significant decrease of Notch 1 and Jagged 1 expression were observed compared to control group (P = 0.023, P = 0.005, P = 0.030, and P = 0.001 P = 0.031 and P = 0.029, respectively). Notch 2 and RANKL were also overexpressed in CP group compared to controls (P = 0.001 and P = 0.011). Significant correlations were observed in AP group between expression levels of the analyzed genes. CONCLUSION: The present findings implicate Notch 2 overexpression in the ethiopathogenesis of bone resorption in aggressive and chronic periodontitis. The down-regulation of Notch 1 and Jagged 1 and loss of their osteoprotective function might cause a more excessive osteoclast formation and contribute to greater osteolysis in aggressive periodontitis.

Drugs and diseases: Summary and consensus statements of group 1. The 5th EAO Consensus Conference 2018.

OBJECTIVES: The task of this working group was to update the knowledge about the use of drugs and biologicals affecting healing of soft tissue and bone during implant treatment or procedures associated with it. Moreover, the impact of titanium particles and biocorrosion on complications and implant survival has been analysed. MATERIALS AND METHODS: The literature in the areas of interest (platelet concentrates, antiresorptive drugs as well as implant-host interaction) was screened using systematic reviews for the former two areas, whereas a narrative critical review was performed for the latter topic. Two manuscripts on platelet concentrates, one manuscript on antiresorptive drugs and one manuscript on the effects of biocorrosion, were presented for group analysis with subsequent discussion in the plenum and final consensus approval. RESULTS: Results and conclusions of the individual reviews of the three topics are presented in the respective papers. Conclusions of the group on strengths and weaknesses of available evidence as well as consensus statements and directions for further research are provided in this study. The following papers were subject to group discussions and formed the basis for the consensus statements: Stähli A, Strauss FJ, Gruber R. () The use of platelet-rich-plasma to enhance the outcomes of implant-related therapies: a systematic review Strauss FJ, Stähli A, Gruber R. (2018) The use of platelet-rich-fibrin to enhance the outcomes of implant-related therapies: a systematic review Mombelli A, Hashim D, Cionca N. () What is the impact of titanium particles and bio-corrosion on implant survival and complications? A critical review Stavropoulos A, Bertl K, Pietschmann P, Pandis N, Morten Schiødt, Klinge B. () The effect of antiresorptive drugs on implant therapy: a systematic review.

Guidelines for development of Implant Dentistry in the next 10 years regarding innovation, education, certification, and associations.

BACKGROUND: During the third Summer Camp of European Association of Osseointegration (EAO), 40 junior representatives from various European societies and associations were brought together to discuss and explore the following topics in Implant Dentistry in the next 10 years: (I) certification, (II) societies and associations, (III) continuing education, and (IV) innovations. AIMS: The aims of all working groups were to identify and outline the present situation in the area of the selected topic and to propose improvements and innovations to be implemented in the following 10 years. MATERIALS AND METHODS: Four different groups were assigned randomly to one of the four working units. The method to discuss the selected topics was World Cafè. The summaries of four topics were then given to all participants for peer review. RESULTS AND CONCLUSIONS: All four groups presented the conclusions and guidelines accordingly: (I) The recognition for Implant Dentistry and accreditation of training programs would lead to an improvement of the quality of care to the benefit of the patients; (II) Dental associations and societies have to continuously improve communication to meet needs of dental students, professionals, and patients (III) European Dental Board should be installed and become responsible for continue dental education; (IV) dental engineering, peri-implant diseases, and digital workflow in dentistry currently have limited tools that do not guarantee predictable results.

Therapeutic concepts and methods for improving dental implant outcomes. Summary and consensus statements. The 4th EAO Consensus Conference 2015.

BACKGROUND: Different therapeutic concepts and methods have been proposed for improving dental implant outcomes in three specific clinical situations: (i) the fresh extraction socket with alveolar ridge preservation protocols; (ii) the posterior maxilla with limited bone height with either the placement of regular-sized implants after sinus elevation and grafting or short dental implants and; (iii) the posterior mandible with limited bone height with either vertical bone augmentation and placement of implants or short dental implants. MATERIALS AND METHODS: Three systematic reviews, based on randomized and controlled clinical trials have evaluated the efficacy of these different therapeutic modalities in terms of dental implant outcomes. RESULTS AND CONCLUSIONS: Interventions aimed for alveolar ridge preservation have shown efficacy in terms of allowing the placement of dental implants and for reducing the need of further augmentation procedures at implant placement. Both therapeutic options, the placement of implants after sinus elevation and grafting or short dental implants, were valid alternatives in the treatment of the posterior maxilla with deficient bone availability, although short implants resulted in fewer complications. Similarly, the placement of implants in vertically augmented bone rendered comparable outcomes with those of short implants in the treatment of the posterior mandible, but short implants resulted in fewer complications.

[Utilization of two different surgical techniques in gingival recession treatment: a comparative study].

INTRODUCTION: Gingival recession is a displacement of gingival margin apically to cement-enamel junction. OBJECTIVE: The aim of this study was to compare the results achieved with two different surgical procedures used in gingival recession treatment. METHODS: Ten patients with bilateral buccal recession on maxillary canines or premolars were included in the study. Professional teeth cleaning was performed before surgery. Recession on the experimental side was treated with connective tissue graft in combination with coronally advanced, split thickness flap (tunnel technique). Control side recession was treated with connective tissue graft in combination with trapezoidal coronally advanced, full thickness flap. Coin toss was used for side decision. The following parameters were evaluated before surgery and 6 months post-op: Vertical Recession Dimension, Clinical Attachment Level, Apico-coronal width of the keratinized tissue, Healing index (Laundry), RES index, and Patient evaluation of esthetic results. Student's t-test was used for statistical analysis. RESULTS: Six months after surgery, mean root coverage was 91.5 +/- 14.1% and 90.1 +/- 14.6% on the experimental and on the control side, respectively. RES index, Healing index (Laundry) and Patient Subjective evaluation of esthetic results showed significantly better results (p < 0.05). CONCLUSION: Both surgical procedures produce highly successful clinical results based on evaluated parameters, but this tunnel technique provides significantly better esthetic results.

Computer-assisted flapless implant surgery in edentulous elderly patients: a 2-year follow up.

OBJECTIVE: The rehabilitation of edentulous mandibles with implant-supported overdentures is a state-of-the-art contemporary implant treatment. Computer-assisted flapless surgery is associated with decreased chairside treatment time, as well as significant reduction in patient postoperative morbidity and discomfort. The aim of this study was to evaluate the protocol of computer-guided surgery in the treatment of edentulous mandibles with overdentures supported by four intraforaminal implants and retained by Locator® attachments in elderly patients, both from a clinician's and a patient's perspective, as well as to assess the stability of the results in a 2-year period. METHOD AND MATERIALS: 15 patients presenting edentulous mandibles and discomfort while wearing conventional overdentures were enrolled in the study. Careful presurgical and computer-assisted 3D treatment planning was performed. Patients were treated with four intraforaminal implants using a computer-assisted flapless approach. All patients were prosthetically rehabilitated with overdentures. Clinical parameters such as peri-implant probing depth (PPD), Plaque Index (PI), and bleeding on probing (BOP) were evaluated. Patients' perceptions regarding the outcome were assessed on visual analog scales (VAS). RESULTS: Out of 15 patients consecutively included in the study, only 10 patients could be treated with the designed protocol. A total of 40 Camlog implants were placed. No implant was lost over a 2-year period. BOP was negative in 82% of sites; mean PPD was 2.34 mm; 8 of the 40 implants showed the absence of keratinized tissue on the lingual or the vestibular aspect. The VAS score of 9.9 demonstrated the satisfaction of the patients. CONCLUSIONS: Within the limitations of this study, the data demonstrate that in a significant number of cases this protocol could not be used for anatomical or technical reasons. In the cases where it could be used, the computer-assisted protocol appeared suitable for treating elderly patients with mandibular edentulism and restoring them with an overdenture in a minimally invasive way. The possibility of placing implants outside the borders of the keratinized tissue is relevant.

[Immediate implant loading with fixed dental restorations--an animal model study].

BACKGROUND/AIM: Immediate loading is considered to be the most innovative technique in contemporary implant dentistry. Recent clinical and experimental findings have demonstrated that only implants with high primary stability can be subjected to immediate loading protocol with predictable results. It is generally accepted that the most important prerequsite for successful osseointegration is achievement and maintenance of implant stability. The aim of this in vivo study was to investigate the possibility for successful application of immediate loading protocol in implant systems with different surface properties. METHODS: In the experimental study 2 mongrel dogs were edentulated bilaterally in the mandibular and maxillary premolar areas. After 3 months implants were placed in a pattern 4 different commercially available implants per quadrant (n = 32): Mk III TiUnite (Nobel Biocare, Sweden), ITI TPS (Straumann, Switzerland), 31-Osseotite (Implant Innovation, USA) and XiVE Cell-Plus (Friadent, Germany). Implants were subjected to immediate loading with 4 unit gold cast bridges, 2 days post implantation. The assessment of implant stability and immediate loading possibilities were done by performing Resonance frequency analysis (RFA). RESULTS: After a 6-month loading period all bridges were in function and all implants occurred well osseointegrated. When summarizing the Implant Stability Quotient (ISQ) values, it was noted that resonance frequency was significantly higher for mandibular implants. The results of this experimental setting showed that all evaluated surfaces achieved good implant stability. Increase of ISQ values was found for all implants in the mandible and partially decrease of ISQ values for maxillary implants after 6 months of functional loading with 4 unit bridges. CONCLUSIONS: Investigated endooseal implants did not show different degree of osseointegration, because there was not statisticaly significant difference among observed parameters (ISQh i ISQp) between implant systems.

The coronally advanced flap in combination with platelet-rich fibrin (PRF) and enamel matrix derivative in the treatment of gingival recession: a comparative study.

OBJECTIVE: The main objective of this study was to evaluate the clinical effectiveness of platelet-rich fibrin membrane used in combination with a coronally advanced flap (CAF) and to compare it with the use of an enamel matrix derivative (EMD) in combination with a coronally advanced flap in gingival recession treatment. MATERIAL AND METHODS: 20 split-mouth cases of maxillary anterior teeth or bicuspids presenting with Miller Class I or II gingival recession were treated with a CAF combined with a platelet-rich fibrin membrane (PRF group) or with EMD (EMD group) placed under a CAF. The following parameters were measured at baseline and at 12 months post treatment: gingival recession (GR), apicocoronal width of the keratinized tissue (WKT), and probing depth (PD). RESULTS: Complete rot coverage in the PRF group was 65% (13 out of 20 recessions) and 60% in the EMD group (12 out of 20 recessions). GR was 4.10 ± 1.05 mm in the PRF group and 3.90 ± 1.00 mm in the EMD group at baseline, and 1.05 ± 0.45 mm in the PRF group and 1.15 ± 0.65 mm in the EMD group at 12 months. The difference observed between the tow groups at 12 months was statistically significant. Average root coverage was 70.5% in the EMD group and 72.1% in the PRF group. WKT was 1.30 ± 0.56 mm in the EMD group and 1.45 ± 0.86 mm in the PRF group at baseline, and 1.90 ± 0.81 mm in the EMD group and 1.62 ± 0.28 mm in the PRF group at 12 months. The difference observed between the two groups at 12 months was not statistically significant. Twelve-month changes in PD were not significantly different between the two groups. The pain intensity was statistically different between the two groups. The pain intensity was statistically different between groups for the first 5 days, favoring the PRF group. CONCLUSIONS: The present study did not succeed in demonstrating any clinical advantage of the use of PRF compared to EMD in the coverage of gingival recession with the CAF procedure. The EMD group showed a higher success rate in increasing WKT than did the PRF group.

[The use of platelet-rich fibrin membrane in gingival recession treatment].

INTRODUCTION: Fibrin, fibronectin, platelet derived growth factor, and transforming growth factors from platelet concetrate are crucial for tissue reparation and regeneration. OBJECTIVE: This study was designed to evaluate clinical effectiveness of activated platelet-rich fibrin (PRF) membrane in treatment of gingival recession. METHODS: 19 gingival recessions Miller class I or II were treated with a coronally advanced flap and the PRF membrane (PRF group). Following the elevation of the flap, bone and root surfaces were covered with the PRF membrane. After suturing, the PRF membrane was covered with a coronally advanced flap. In the same patients, 19 other gingival recessions were treated with CTG in combination with the coronally advanced flap (the CTG group). Clinical recordings were made of vertical recession depth (VRD), probing depth (PD), clinical attachment level (CAL) and keratinized tissue width (KTW) before and 12 months after mucogingival surgical treatment. Clinical evaluation of healing events was estimated with recordings of the healing index (HI). Recordings of HI were performed in the 1st, 2nd and 3rd week post-surgically. RESULTS: Mean root coverage was significant in both groups (the PRF group 79.94% and the CTG group 88.56% %; p < 0.01). The difference between the two tested groups was not statistically significant. Results of the keratinized tissue width showed significant increase (p < 0.05) 12 months after the surgery in both, the PRF and CTG groups. Results of KTW showed statistical significance of recorded differences obtained in the two evaluated groups (p < 0.05). There was no statistical significance in reduction of PD and CAL recorded in the PRF and CTG groups. The values of HI recorded in the 1st and 2nd week postoperatively were significantly enhanced in the PRF group (p < 0.05). CONCLUSION: Results of this study confirm both procedures as effective with equivalence of clinical results in solving gingival recession problems. The utilization of the PRF resulted in a decreased postoperative discomfort and advanced tissue healing.