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Objectives: Aim of this study was to compare the soft tissue response to implant abutments made of titanium, zirconia, zirconia veneered with feldspar ceramics and PEEK by various clinical, histological, microbiological, and molecular biological markers in an experimental model., Materials and Methods: A total of 40 experimental one-piece healing abutments of four different materials were mounted on bone level implants in 20 volunteering patients (split-mouth design). After a three-month period of open healing, clinical parameters at the abutments were assessed and adjacent mucosa was sampled for inflammatory cytokine mRNA concentrations and histological analysis by a novel method. In addition, PISF samples were obtained for the analysis of periodonto-pathogenic bacteria counts and active MMP-8 levels. Marginal bone level change was measured by intra oral radiographs., Results: Abutments of the different materials did not exhibit significant differences regarding clinical parameters, pathogenic bacteria counts or pro-inflammatory cytokine concentrations. Likewise, no significant differences were detected regarding soft tissue morphology or bone level change. Compared to titanium abutments, significantly less mononuclear inflammatory cells were detected in the mucosa at abutments made of zirconia veneered with feldspar ceramics., Conclusions: All examined abutment materials exhibited a similar soft tissue response compared to titanium and histological data did not reveal early signs of elevated inflammation caused by PEEK- and feldspar-veneered zirconia abutments. Due to the short observation period and the small sample size, a final conclusion on the long-term suitability of those abutment materials cannot be drawn. However, based on the presented data, we consider further studies on that subject as appropriate., (© 2022 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Purpose: The aim of this study was to longitudinally evaluate changes in alveolar bone crest (ABC) levels and differences in resorption rates (RR) between the tested grafting materials following alveolar ridge preservation (ARP) after tooth extraction after 1, 2, and 3 years (T1-T8) of clinical function., Methods: Patients were randomly assigned to two different bone allografts (group 1 maxgraft ® , group 2 Puros ® ) for ARP. Non-restorable teeth were minimal traumatically extracted. Sockets were augmented with the tested materials and covered with a pericardium membrane. After 4 months of healing, 36 implants were placed and sites were clinically and radiographically monitored in the mesial (ABC-M), the distal (ABC-D, T1-T8), the bucco-lingual (ABC-BL), buccal (ABC-B) and oral (ABC-O) aspect (T1-T4)., Results: Changes in (ABC-M), (ABC-D), (ABC-BL), (ABC-B), and (ABC-O) levels showed statistically highly significant differences between T1 and T2 for both bone allografts (p < 0.001). Changes at the ABC-M and ABC-BL levels between T2 and T3 of group 1 showed a statistically significant difference (p < 0.001). Both groups achieved and maintained increased ABC levels without statistically significant differences throughout the monitoring periods of 1-3 years (T6-T8) of clinical function. No failures or adverse events were observed., Conclusions: To the best of our knowledge, this study is within its limitations the first study to directly compare ABC-changes and differences in RR of two different allogeneic grafting materials for a period of 3 years after ARP. It was demonstrated to be, despite significant differences in RR, a successful method of preserving increased ABC levels through 1, 2, and 3 years of clinical function. Trial registration DRKS00013010, registered 07/30/2018, http://apps.who.int/trialsearch., (© 2022. The Author(s).)

Objectives: To introduce a standardized and less invasive clinical model that provides histological information on the abutment-mucosa interface in humans., Materials and Methods: New experimental healing abutments were left in an open healing position on bone-level implants in the interforaminal region of the mandibles in six edentulous patients. The one-piece abutments were hollow cylinder-shaped with two lateral openings that allow for ingrowth of the peri-implant mucosa into the central abutment cavity. After three months of healing, abutments and ingrown mucosa were sampled and processed for histological analysis in a non-separated resin-embedding technique. To test the validity of the new model, the ingrown tissue was compared to the peri-implant mucosa around the same samples., Results: None of the experimental abutments exhibited signs of failure, and all samples showed mucosal ingrowth to the inner-abutment cavity. Comparison of ingrown tissue and peri-implant mucosa revealed no significant differences regarding the traits: tissue morphology, quality of collagen fibers, and adherence to the abutment. Ingrown mucosa exhibited a tendency for higher leukocyte infiltration., Conclusions: The presented model is a promising approach to reduce invasiveness during the sampling process for human non-separated abutment biopsies., (© 2021 The Authors. Clinical Oral Implants Research published by John Wiley & Sons Ltd.)

Adult patients with oral manifestations of untreated syndromic malformations usually exhibit a high degree of suffering. In this clinical report, we describe the implant-supported prosthetic treatment of a patient with cleidocranial dysplasia, a rare autosomal-dominant inherited malformation syndrome. Therapy for oral manifestations of cleidocranial dysplasia should be started in early childhood; however, the 26-year-old patient in the present study had not undergone orthodontic therapy in childhood. The treatment measures performed prior to this study were limited to the removal of several permanent teeth. Surgical pretreatment, placement of six implants each in the maxilla and mandible, and prosthetic restoration are described. The implantation was guided using a three-dimensional template. Long-term immediate temporary restoration and immediate loading of the implants were performed. The definitive prosthetic restoration was completed using fixed, acrylic resin-veneered screw-retained fixed dental prostheses. The clinical and radiological parameters observed in this case suggest that surgical and prosthetic procedure concepts from implantology can be adopted for patients with CCD.

Objectives: Cell-free DNA (cfDNA) harboring mutations has been found in patients with diseases. Experimental studies have shown that cfDNA can be transmitted, leading to transformations in the host. In the present study, we evaluated whether bone allograft material contains cfDNA and whether this foreign cfDNA can be released into the patient's blood circulation., Materials and Methods: Plasma samples were collected preoperatively and postoperatively on the same day, at 5 weeks, and 4 months from 25 women who received bone allograft material (test group) from male donors and from 10 women who were treated with autologous graft (control group, only pre- and postoperative samples were collected). DNA was quantified and characterized in bone material and plasma samples by quantitative PCR with primers specific for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Y chromosome and gel electrophoresis. DNA in bone material was digested by different concentrations of DNase I., Results: We detected between 1 and 1.8 μg cfDNA fragments at a length around 601 base pairs (bp) and smaller in each 100 mg allograft. Treatment of the allograft with DNase I completely degraded the longer but not the shorter DNA 90-bp fragments. Y-DNA was not detected in the patients' bloodstream at any time during the treatment and follow-up, but elevated levels of circulating cfDNA could be measured immediately postoperatively., Conclusions: Our results suggest that a transmission of DNA from allografts used for alveolar ridge reconstruction in humans is unlikely. The observed increase in circulating cfDNA in allograft and autograft patients immediately postoperatively may be elicited by the surgical procedure., Clinical Relevance: The results support the safety of allograft materials. The results suggest that human allograft materials seem not to release DNA into the blood since we did not measure Y-DNA with our technique.

Dental implants are important tools for restoring the loss of teeth. The rapid growth and periodic regeneration of antlers make Sika deer a good and less invasive alternative model for studying bone remodelling in mammals. We developed a special loading device for antlers and analysed the bone reaction around unloaded implants and under immediate loading conditions until osseointegration occurred. In micro-computed tomography images, the density of antler tissue around the implants increased as the loading time increased. This finding was histologically confirmed by the good osseointegration observed in unloaded and loaded specimens. Antler tissue displays a similar healing process to human bone. The use of an antler model is a promising alternative for implant studies that does not require animal sacrifice., Competing Interests: The authors declare the following interests: Materiel support in the form of implants for the investigations in deer antlers was provided by the commercial company Straumann GmbH (Freiburg, Germany). Material support in the form of implants for the initial investigations to improve the loading device was provided by the commercial company Friadent GmbH (Mannheim, Germany). There are no patents, products in development, or marketed products to declare. This does not alter the authors’ adherence to all PLOS ONE policies on sharing data and materials.

Objectives: Bone grafts are often used to enhance bone volume/quality prior to implantation insertion. This systematic review compares the histomorphometric effectiveness of bone grafts in an evidence-based manner., Data: Randomized clinical trials comparing histomorphometrically the % of newly-formed bone between two grafts were included. Risk of bias within and across studies was assessed with the Cochrane tool and the GRADE approach, respectively. Random-effects pairwise meta-analyses were conducted, followed by network meta-analysis, network meta-regression and sensitivity analyses., Sources: Four electronic databases were searched from inception to June 2015 without limitations., Study Selection: A total of 12 trials (5 parallel; 7 cluster) with a total of 231 patients (302 grafted sites) were included. No statistically significant differences were found in the % of new bone from pairwise comparisons between any two bone grafts. Treatment ranking based on the evidence network indicated that autografts presented the highest percentage of new bone, followed by synthetic grafts, xenografts, and allografts. No differences according to patient age, sex, healing time, membrane used or kind of surgical graft use were identified. Our confidence on pairwise comparisons was moderate to very low due to study limitations, inconsistency, and imprecision; our confidence on graft ranking was moderate due to study limitations., Conclusions: No significant differences were found in the percentage of new bone between any two grafts., Clinical Significance: Synthetic bone substitutes or xenologous bone grafts can be used as an alternative to autologous graft in order to overcome problems of additional surgeries or limited graft availability., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Peri-implantitis (PI) is characterized by inflammation and bone resorption eventually leading to implant failure, but the characteristic pathologic determinants are undefined to date. This study aims to elucidate the parameters involved in PI pathogenesis, including intraoral implant retention time, extent of bone loss, smoking history, and identification of osteoimmunological markers for inflammation and bone loss. Peri-implant tissues (n = 21) displaying clinically diagnosed PI from patients with vertical bone loss ranging from 0-12 mm and implant function period between 1 and 60 months were evaluated by histochemistry and immunohistochemistry for TRAP, CD3, RANK, RANKL, OPG, and TNF-α. Statistical analyses were performed with the Welch test and correlation coefficients were calculated. Most bone resorption occurred during the first 12 months of implant function and correlated with the extent of inflammation, although histological signs of inflammation strongly varied between samples from minimal appearance of inflammatory cells to extended infiltrates. Implant function period and smoking history did not significantly affect the degree of inflammation. Higher RANK levels emerged in the first 12 months of implant function compared to longer retention times and were negatively correlated to the occurrence of RANKL. Additionally, histological signs of inflammation were about two-fold higher in specimens with bone resorption up from 5 mm compared to under 5 mm. CD3(+) cells were more prevalent in extensive inflammatory infiltrates and samples derived from smokers. Our analyses proved that PI-induced bone loss is differentially influenced by the parameters evaluated in this study, but a distinct interconnection between disease severity and implant retention time can be established.

Objectives: Simultaneous lateral augmentation and implant placement is considered as standard procedure in deficient edentulous ridges in oral implantology. Histological studies monitoring osteogenesis after application of alloplastic bone substitutes in humans are scarce. Bone formation upon simultaneous augmentation with biphasic calcium phosphate (BCP) and implantation was histologically investigated after 6 months in situ. The results of this secondary analysis are reported tempting to ascribe specific observations to uneventful submerged healing or compromised healing of soft tissues including occurrence of dehiscences and premature graft exposure., Materials and Methods: Histology of biopsies from lateral, crestal bone augmentations using alloplastic BCP comprising seven sites with compromised, prematurely exposed healing and six sites with uneventful submerged healing was investigated for expression of osteogenic, osteoclastogenic, and angiogenic differentiation markers., Results: Histology revealed alkaline phosphatase (ALP)-positive osteoblasts and immunoreactivity for osteogenic markers osteocalcin and collagen type I in biopsies with submerged healing, while inflammatory infiltrates and accumulations of multinucleated giant cells around BCP granules were observed in compromised sites. All specimens presented adequate vessel density. Multinucleated giant cells showed inconsistent staining for the osteoclast marker tartrate-resistant acid phosphatase (TRAP)., Conclusions: The histological findings of this study indicate an osteoconductive nature of the BCP applied. Premature exposure of the bone substitute reduced new bone formation and may bear a risk for inflammatory and foreign body reactions., Clinical Relevance: A predictable appositional bone formation in simultaneously augmented sites using BCP is linked to an uneventful healing process.

Aims: Stability of orthodontic miniscrew implants is prerequisite to their success and durability in orthodontic treatment. As investigations revealed a positive correlation of miniscrew stability to periimplant bone quality, it has been the aim of this study to analyze the bone structure of resection preparations of human mandibles histologically by investigating the samples according to age, gender and exposure to radiotherapy., Methods: Inflammation- and tumor-free alveolar bone sections from human mandibles (n = 31) with previously diagnosed carcinoma, chronic osteomyelitis or cysts were analyzed histomorphologically and histomorphometrically as to the dimension of trabeculae in cancellous areas. Group A investigated the impact of a history of radiation therapy, group B of gender and group C contrasted biopsies from individuals aging under 60 or over 60 years. Statistics were performed using the Kruskal-Wallis-test., Results: Radiation, gender and age did not significantly influence bone density. The mean bone density averaged 40.7 ± 15.0% of spongiosa for the total collective with a median age of 58.4 years ± 14.7 years., Conclusions: Our findings provide new information on bone quality, thus contributing to a more precise evaluation of the parameters affecting and those not affecting miniscrew implant stability. On the basis of these results, the formulation of clinical guidelines for risk assessment of therapeutic approaches in patients prior to insertion of orthodontic skeletal anchorage devices seems to be conceivable., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Immediate loading of dental implants is only possible if a firm bone-implant anchorage at early stages is developed. This implies early and high bone apposition onto the implant surface. A nanostructured coating material based on an osseoinductive bone grafting is investigated in relation to the osseointegration at early stages. The goal is to transmit the structure (silica matrix with embedded hydroxyapatite) and the properties of the bone grafting into a coating material. The bone grafting substitute offers an osseoinductive potential caused by an exchange of the silica matrix in vivo accompanied by vascularization. X-ray diffraction and transmission electron microscopy analysis show that the coating material consists of a high porous silica matrix with embedded nanocrystalline hydroxyapatite with the same morphology as human hydroxyapatite. An in vitro investigation shows the early interaction between coating and human blood. Energy-dispersive X-ray analysis showed that the silica matrix was replaced by an organic matrix within a few minutes. Uncoated and coated titanium implants were inserted into the femora of New Zealand White rabbits. The bone-to-implant contact (BIC) was measured after 2, 4, and 6 weeks. The BIC of the coated implants was increased significantly at 2 and 4 weeks. After 6 weeks, the BIC was decreased to the level of the control group. A histological analysis revealed high bone apposition on the coated implant surface after 2 and 4 weeks. Osteoblastic and osteoclastic activities on the coating material indicated that the coating participates in the bone-remodeling process. The nanostructure of the coating material led to an exchange of the silica matrix by an autologous, organic matrix without delamination of the coating. This is the key issue in understanding initial bone formation on a coated surface.

Purpose: This study was conducted to analyze how a cleaning treatment using plasma of argon would affect fibroblast growth on titanium disks at different time points to determine whether this treatment could enhance soft tissue healing around titanium dental implant abutments., Materials and Methods: Sixty sterile disks made of machined grade 5 titanium were divided into two groups; 30 disks were left untreated (control) and 30 were cleaned using plasma of argon (test). To simulate clinical conditions during soft tissue healing around titanium abutments, both groups were immersed in a culture of murine fibroblasts (L929) for 2, 8, or 48 hours. After preparation, they were stained using 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) to label the cellular nuclei and fluorescent phalloidin to label the cellular bodies. The nuclei were counted, and cellular bodies were analyzed with fluorescent microscopy and imaging analysis software. Analysis was performed at the three different time points., Results: Fibroblast adhesion for the test group was statistically significantly greater versus the control group at 2 and 8 hours but not at 48 hours. At 2 and 8 hours, the cellular bodies in the test group appeared flatter and more spread out, revealing more advanced cellular adhesion, compared to the cells observed in the control group. At 48 hours, the test and control specimens were nearly indistinguishable., Conclusion: The removal of organic and inorganic contaminants from the surfaces of titanium disks using plasma of argon accelerated fibroblast adhesion in the early stages of colonization (2 to 8 hours). This effect disappeared after 48 hours as a result of saturation. Clinically, abutment cleaning using plasma of argon might positively affect soft tissue healing in early stages.

In the literature has been demonstrated that when an implant is placed in the oral environment, changes in peri-implant hard tissue level may occur. Several clinical procedures have been advocated to clinically minimize this bone resorption. However, minimal attention was paid to the soft- and hard-tissue abutment interaction. The present clinical preliminary study is intended to radiologically analyze the effect of glow-discharged abutments on hard tissue level changes after 18 months of prosthetic loading. Five patients needing an implant supported restoration in the anterior maxillary area with thin gingival tissue biotype and healed bone were recruited. An implant was inserted and a titanium abutment was glow-discharged with an Argon plasma treatment in a plasma reactor and, immediately after, definitively screwed at 30N. Provisional restoration was therefore positioned. Three months later, definitive restoration was performed. Digital periapical standardized radiographs were taken at the time of surgery, 6 and 18 months thereafter. Radiographic analysis was carried out using image analysis software. At baseline, interproximal radiographs revealed no bone defect around implants in both groups. After 6 months from baseline, the postoperative interproximal radiographs revealed an average bone loss of 0.09mm (range 0.0-0.3mm, SD=0.144mm). After 18 months from baseline, the periapical X-ray showed a stable condition of bone remodeling (mean value: 0.09, range 0.0-0.5mm, SD=0.08mm). Within the limit of this study, glow-discharged abutments have been demonstrated to positively affect hard tissue reaction to implant restoration., (Copyright © 2012 Elsevier GmbH. All rights reserved.)

Purpose: This prospective randomized matched-pair controlled trial aimed to evaluate marginal bone levels and soft tissue alterations at implants restored according to the platform-switching concept with a new inward-inclined platform and compare them with external-hexagon implants., Materials and Methods: Traditional external-hexagon (control group) implants and inward-inclined platform implants (test group), all with the same implant body geometry and 13 mm in length, were inserted in a standardized manner in the posterior maxillae of 40 patients. Radiographic bone levels were measured by two independent examiners after 6, 12, and 18 months of prosthetic loading. Buccal soft tissue height was measured at the time of abutment connection and 18 months later., Results: After 18 months of loading, all 80 implants were clinically osseointegrated in the 40 participating patients. Radiographic evaluation showed mean bone losses of 0.5 ± 0.1 mm (range, 0.3 to 0.7 mm) and 1.6 ± 0.3 mm (range, 1.1 to 2.2 mm) for test and control implants, respectively. Soft tissue height showed a significant mean decrease of 2.4 mm in the control group, compared to 0.6 mm around the test implants., Conclusions: After 18 months, significantly greater bone loss was observed at implants restored according to the conventional external-hexagon protocol compared to the platform-switching concept. In addition, decreased soft tissue height was associated with the external-hexagon implants versus the platform-switched implants.

Purpose: This study sought to determine whether there was a correlation between bone resorption and individual bone patterns in patients treated with implants restored conventionally or using the platform-switching concept., Materials and Methods: Ten patients (24 implants) were randomly assigned to receive implants with different platform diameters (3.8, 4.3, 4.8, or 5.5 mm), all of which were restored with standard 3.8-mm-diameter abutments. Biopsy specimens were obtained prior to implant placement, and histologic and immunohistochemical analyses were performed. Standardized radiographs were made at each site after implant placement and at 36 months after prosthetic loading and bone levels were determined., Results: One patient dropped out, resulting in a total of 9 patients and 22 implants. Mean bone resorption was 1.358 mm for non-platform-switched implants; mean resorption was 0.832, 0.486, and 0.375 mm for implant platforms of 4.3, 4.8, and 5.5 mm, respectively. After standardization of peri-implant bone remodeling values, a borderline direct correlation between peri-implant bone changes and levels of biglycans was found. At the same time, a borderline indirect correlation between bone changes and levels of tumor necrosis factor-a was found., Conclusions: Within the limit of this study, which was conducted in a small patient sample over a short observation period, an individual resorption trend was detected and paralleled by immunohistochemical findings. Individual local bone structure and quality seemed to be correlated to peri-implant bone resorption. Correlations between biglycan and tumor necrosis factor-a and bone resorption should be confirmed by a larger patient sample.

In recent years, the use of immediately loaded implants became more acceptable as a standard protocol for completely edentulous lower jaw and/or partially edentulous upper jaw cases, predominantly in the anterior region, after it was one of the cornerstones of the early protocols to avoid any occlusal loading of the implants for at least 3 months. This technique could potentially provide immediate function and aesthetics to the patient. This review aims to present the clinical indications of the immediately loaded protocol according to the individual cases and the corresponding risk factors and contraindications. The clinical, biomechanical and biological requirements concerning bone quality, occlusal loading and implant primary stability are discussed. Primary stability in immediate loading is determined rather by surgical than biological parameters. Peri-implant osteogenesis leading to secondary stability depends on the same biological factors than in unloaded implant healing. However, specific mechanical effects on the biology of immediate loading osseointegration are yet to be investigated.