Complications related to bone augmentation procedures of localized defects in the alveolar ridge. A retrospective clinical study

Spontaneous regeneration of bone following mandibular ramus bone harvesting: a CBCT analysis

The aim of this study was to evaluate healing at the donor site following autogenous block graft harvesting from the mandibular ramus. In this retrospective study, cone beam computed tomography images taken at different time-points were examined, and the volumes of preoperative and postoperative regions of interest were calculated in the software. Images were classified into four groups: 0-3 months, 4-6 months, 7-12 months, and >12 months post-surgery. To characterize the healing process over time, statistical analyses were conducted for both the 70% and 80% healing thresholds. Nearly half (n = 15, 47%) of the 32 patients included in this study achieved 70% bone healing within 4-12 months post-surgery. At the end of the 28-month period covered by this study, 21 patients (66%) had achieved 70% bone healing. The median time to achieve 70% healing was 9 months, while the median time to achieve 80% healing was 28 months. The findings of this study validate the feasibility of reutilizing the mandibular ramus area for additional bone augmentation when other intraoral sites are unavailable.

Application of BMP-2 and its gene delivery vehicles in dentistry

The restoration of bone defects resulting from tooth loss, periodontal disease, severe trauma, tumour resection and congenital malformations is a crucial task in dentistry and maxillofacial surgery. Growth factor- and gene-activated bone graft substitutes can be used instead of traditional materials to solve these problems. New materials will overcome the low efficacy and difficulties associated with the use of traditional bone substitutes in complex situations. One of the most well-studied active components for bone graft substitutes is bone morphogenetic protein-2 (BMP-2), which has strong osteoinductive properties. The aim of this review was to examine the use of BMP-2 protein and gene therapy for bone regeneration in the oral and maxillofacial region and to discuss its future use.

Evaluating risk factors and complications in mandibular ramus block grafting: a retrospective cohort study

OBJECTIVES

This retrospective cohort study aimed to identify the complications and risk factors associated with alveolar grafting using autologous mandibular ramus grafts, guided by the research question: What are the complications encountered in patients undergoing alveolar bone grafting using autologous mandibular ramus block and what are the risk factors associated with the development of these complications?

MATERIALS AND METHODS

The study included 70 patients who underwent alveolar crest augmentation with autologous mandibular ramus block grafting. Intraoperative, early postoperative, and late postoperative complications were analyzed, as were various risk factors.

RESULTS

The results showed that the majority of patients had successful outcomes with minimal complications. Sex was found to significantly influence the visibility of the inferior alveolar nerve (IAN). Early postoperative complications were associated with IAN visibility and the use of a single screw for graft fixation. Late postoperative complications were significantly associated with the presence of infection.

CONCLUSION

The findings emphasize the importance of careful surgical techniques, infection prevention, and patient selection in minimizing complications.

CLINICAL RELEVANCE

This article may contribute to clinicians' and so patients' understanding of potential risk factors associated with over all ramus block grafting procedure. Based on this information, clinicians can also improve their ability to manage risk factors and associated complications and compare ramus block grafting with other alternatives to determine the best treatment approach for that particular patient.

Risk Factors for Early Implant Failure and Selection of Bone Grafting Materials for Various Bone Augmentation Procedures: A Narrative Review

Implant therapy is now an established treatment with high long-term success and survival rates. However, early implant failure, which occurs within one year of superstructure placement, occurs at a higher rate than late failure, which is represented by peri-implantitis caused by bacterial infection. Furthermore, various risk factors for early failure have been reported, including patient-related factors, such as systemic diseases, smoking, and bone quality and quantity, as well as surgery-related factors, such as surgeons' skill, osteogenesis technique, and selection of graft material, and implant-related factors, such as initial implant fixation and implant length diameter. Due to the wide variety of relevant factors reported, it is difficult to identify the cause of the problem. The purpose of this review is to discuss the risk factors associated with various types of bone augmentation which have a close causal relationship with early implant failure, and to determine the optimal bone grafting material for bone augmentation procedures to avoid early implant failure.

Digital PBL-CBL teaching method improves students' performance in learning complex implant cases in atrophic anterior maxilla

Background

The clinical teaching of esthetic implant-supported restoration of the atrophic maxilla is challenging due to the complexity and unpredictability of bone and soft tissue augmentation. The traditional problem-based learning and case-based learning method (PBL-CBL method) with a full digital workflow (digital PBL-CBL method) provides the students a chance to view clinical cases in a more accurate and measurable way. The aim is to evaluate the effectiveness of the new digital PBL-CBL method in teaching complex implant cases in esthetic area.

Materials & Methods

A full digital workflow of dental implant therapy was established for patients with severely atrophic anterior maxilla. The digital data of cases done in the new workflow was used as teaching materials in digital PBL-CBL teaching. Fifty-four postgraduate students were randomly selected and divided into three groups, including traditional PBL-CBL group (students taught in a PBL-CBL method with no digital cases), digital PBL-CBL group (students taught in a PBL-CBL method with full digital cases) and control group (students taught in didactic teacher-centered method). After training for three months, a study of the students' opinions on the corresponding teaching method was carried out through a feedback questionnaire. A theory test was used to evaluate students' mastery of knowledge about tissue augmentation and esthetic implant restoration. A case analysis was used to determine whether students could apply the knowledge to problem solving.

Results

The digital PBL-CBL method resulted in a higher rate of satisfaction than the traditional PBL-CBL method and the didactic teacher-centered method in all items except for "This approach decreases extracurricular work". Case analysis scores of the digital PBL-CBL group were significantly higher than that of the traditional PBL-CBL group and the control group. For the theory test, the digital PBL-CBL group (61.00 ± 6.80) but not traditional PBL-CBL group (55.22 ± 9.86) obtained a significant higher score than the control group (45.11 ± 12.76), although no significant difference was found between the digital PBL-CBL group and the traditional PBL-CBL group.

Conclusion

Compared with other methods, students taught with the digital PBL-CBL method showed higher satisfaction and better performance in acquisition of academic knowledge and ability in solving practical clinical problems. The digital PBL-CBL method provided a promising alternative for teaching complex implant cases at the anterior maxilla.

Hydrogel based soft tissue expanders for orodental reconstruction

Tension-free flap closure to prevent soft tissue dehiscence is a prerequisite for successful bone augmentation in orodental reconstructive surgery. Since soft tissue contour follows the underlying jaw bony architecture, resorption of alveolar (jaw) bone limits the availability of soft tissue for wound closure following major bone reconstruction, required to facilitate oral rehabilitation with endosseous dental implants following tooth loss. Although there are several clinical procedures to increase soft tissue volume, these techniques are complicated and technically demanding. Soft tissue expansion, an established technique in reconstructive surgery, is an ideal alternative to generate surplus soft tissue prior to bone augmentation and dental implant placement. Increase in tissue volume can be achieved by using soft tissue expanders (STEs). Contemporary STEs have evolved from silicone balloons to osmotically inflating hydrogel-based systems. Here, we provide an overview of STEs in clinical oral surgery, outline the current research in STEs, and an update on recent clinical trials as well as the associated complications. Also, the mechanism governing soft tissue expansion and the critical factors that control the expansion process are covered. Design considerations for STEs for intraoral applications are given particular attention. Finally, we present our perspectives on utilization of minimally invasive methods to administer STEs for orodental applications. STATEMENT OF SIGNIFICANCE: Soft tissue expansion is required for a range of reconstructive applications and more notably in regenerative dentistry for vertical bone augmentation. This review describes the commercially available soft tissue expanders along with the latest systems being currently developed. This review insightfully discusses the biological and physical mechanisms leading to soft tissue expansion and critically assesses the design criteria of soft tissue expanders. A particular focus is given on the development of a new generation of hydrogel-based soft tissue expanders; their chemistry and required physical properties for tissue expansion is described and the obstacles towards clinical translations are identified. Finally, the review elaborates on promising minimally invasive injectable hydrogel-based tissue expanders and highlights the beneficial features of these systems.

Complications following alveolar ridge augmentation procedures

Oral rehabilitation through implant supported dental restorations often requires a ridge augmentation procedure (RAP) prior to implant fixture placement since tooth extraction/loss results in alveolar ridge deficiencies. Although RAP-related surgical techniques and biomaterials have been in practice for several decades, outcomes are not always predictable. Post-surgical complications experienced during the early or late wound healing phases may jeopardize the targeted ideal ridge dimensions, required for implant fixture placement, and may have other consequences, such as negatively impacting the patient's quality of life. This review describes reported post-surgical complications following RAP under the following subtitles: complications by tissue type, complications in function and aesthetics, complications by healing time, complications by biomaterial type, and complications by surgical protocol modalities. Specifically, RAP performed by using particulate bone graft substitutes and related complications are explored. Modalities developed to prevent/manage these complications are also discussed.

Injectable pH and Thermo-Responsive Hydrogel Scaffold with Enhanced Osteogenic Differentiation of Preosteoblasts for Bone Regeneration

Bone fractures are common in the geriatric population and pose a great economic burden worldwide. While traditional methods for repairing bone defects have primarily been autografts, there are several drawbacks limiting its use. Bone graft substitutes have been used as alternative strategies to improve bone healing. However, there remain several impediments to achieving the desired healing outcomes. Injectable hydrogels have become attractive scaffold materials for bone regeneration, given their high performance in filling irregularly sized bone defects and their ability to encapsulate cells and bioactive molecules and mimic the native ECM of bone. We investigated the use of an injectable chitosan-based hydrogel scaffold to promote the differentiation of preosteoblasts in vitro. The hydrogels were characterized by evaluating cell homogeneity, cell viability, rheological and mechanical properties, and differentiation ability of preosteoblasts in hydrogel scaffolds. Cell-laden hydrogel scaffolds exhibited shear thinning behavior and the ability to maintain shape fidelity after injection. The CNC-CS hydrogels exhibited higher mechanical strength and significantly upregulated the osteogenic activity and differentiation of preosteoblasts, as shown by ALP activity assays and histological analysis of hydrogel scaffolds. These results suggest that this injectable hydrogel is suitable for cell survival, can promote osteogenic differentiation of preosteoblasts, and structurally support new bone growth.

Palatal bone block: A predictable bone augmentation technique for restricted maxillary defect

Bone grafting for implant dentistry depends on bone quality, quantity, and biological principles for good outcome. Autogenous bone as donor remains the gold standard among all the available materials. However, it carries unpredictable morbidity and need for different surgical sites. In our report, we describe a simplified approach in bone augmentation for restricted maxillary atrophic defect within the same surgical site as a harvesting site. The method can be an alternative for different intraoral surgical harvesting sites. The patient's left maxillary central incisor before treatment had a large bony defect which was reconstructed though single site approach of augmentation. The implant-supported restoration with healthy periodontium around even after 2 years of review looks promising. The approach can be an alternative for different intraoral surgical sites.

Pro-angiogenic photo-crosslinked silk fibroin hydrogel: a potential candidate for repairing alveolar bone defects

OBJECTIVE

This study aimed to develop a pro-angiogenic hydrogel with in situ gelation ability for alveolar bone defects repair.

METHODOLOGY

Silk fibroin was chemically modified by Glycidyl Methacrylate (GMA), which was evaluated by proton nuclear magnetic resonance (1H-NMR). Then, the photo-crosslinking ability of the modified silk fibroin was assessed. Scratch and transwell-based migration assays were conducted to investigate the effect of the photo-crosslinked silk fibroin hydrogel on the migration of human umbilical vein endothelial cells (HUVECs). In vitro angiogenesis was conducted to examine whether the photo-crosslinked silk fibroin hydrogel would affect the tube formation ability of HUVECs. Finally, subcutaneous implantation experiments were conducted to further examine the pro-angiogenic ability of the photo-crosslinked silk fibroin hydrogel, in which the CD31 and α-smooth muscle actin (α-SMA) were stained to assess neovascularization. The tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were also stained to evaluate inflammatory responses after implantation.

RESULTS

GMA successfully modified the silk fibroin, which we verified by our 1H-NMR and in vitro photo-crosslinking experiment. Scratch and transwell-based migration assays proved that the photo-crosslinked silk fibroin hydrogel promoted HUVEC migration. The hydrogel also enhanced the tube formation of HUVECs in similar rates to Matrigel®. After subcutaneous implantation in rats for one week, the hydrogel enhanced neovascularization without triggering inflammatory responses.

CONCLUSION

This study found that photo-crosslinked silk fibroin hydrogel showed pro-angiogenic and inflammation inhibitory abilities. Its photo-crosslinking ability makes it suitable for matching irregular alveolar bone defects. Thus, the photo-crosslinkable silk fibroin-derived hydrogel is a potential candidate for constructing scaffolds for alveolar bone regeneration.

Comparing clinical outcomes of immediate implant placement with early implant placement in healthy adult patients requiring single-tooth replacement in the aesthetic zone: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

The aim of this systematic review and meta-analysis was to assess the clinical efficacy of the immediate implant placement (IIP) protocol in the aesthetic zone with early dental implant placement (EIP) protocol.

METHODS

Electronic databases MEDLINE (via OVID), EMBASE (via OVID), ISI Web of Science core collection, Cochrane, SCOPUS, and Google Scholar were searched for the studies comparing the two clinical protocols. Randomised controlled trials were included. Cochrane Risk of Bias tool (ROB-2) was used to assess the quality of included students.

RESULTS

A total of six studies were selected. Implant failure was observed at 3.84%, 9.3%, and 4.45% in three studies while in the other studies, no implant failure was reported. Meta-analysis of four studies showed no statistically significant difference in the vertical bone levels between IIP and EIP (148 patients), mean difference (MD)0.10 [95% CI: -0.29 to 0.091.32] P > 0.05. Meta-analysis of two studies showed the probing depth between IIP versus EIP was not significantly different (100 patients), mean difference(MD)-0.00 [95% CI; -0.23 to 0.23]; P > 0.05. The pink aesthetic score (PES) was improved in EIP as compared to IIP with a statistically significant difference (P < 0.05).

CONCLUSION

The available evidence supports the clinical efficacy of the IIP protocol. Present findings indicate aesthetics and clinical results of immediate implant placement protocol are comparable to early and delayed placement protocols. Therefore, future research with long-term follow-up is warranted.

Bioactive Glasses in Periodontal Regeneration A Systematic Review

Bioactive glasses (BAGs) are surface-active ceramic materials that can be used in bone regeneration due to their known osteoconductive and osteoinductive properties. This systematic review aimed to study the clinical and radiographic outcomes of using BAGs in periodontal regeneration. The selected studies were collected from PubMed and Web of Science databases, and included clinical studies investigating the use of BAGs on periodontal bone defect augmentation between January 2000 and February 2022. The identified studies were screened using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. A total of 115 full-length peer-reviewed articles were identified. After excluding duplicate articles between the databases and applying the inclusion and exclusion criteria, 14 studies were selected. The Cochrane risk of bias tool for randomized trials was used to assess the selected studies. Five studies compared using BAGs with open flap debridement (OFD) without grafting materials. Two of the selected studies were performed to compare the use of BAGs with protein-rich fibrin, one of which also included an additional OFD group. Also, one study evaluated BAG with biphasic calcium phosphate and used a third OFD group. The remaining six studies compared BAG filler with hydroxyapatite, demineralized freeze-dried bone allograft, autogenous cortical bone graft, calcium sulfate β-hemihydrate, enamel matrix derivatives, and guided tissue regeneration. This systematic review showed that using BAG to treat periodontal bone defects has beneficial effects on periodontal tissue regeneration. OSF Registration No.: 10.17605/OSF.IO/Y8UCR.

Role of hormones in bone remodeling in the craniofacial complex: A review

Background

Diseases such as periodontitis and osteoporosis are expected to rise tremendously by 2050. Bone formation and remodeling are complex processes that are disturbed in a variety of diseases influenced by various hormones.

Objective

This study aimed to review and present the roles of various hormones that regulate bone remodeling of the craniofacial complex.

Methods

A literature search was conducted on PubMed and Google Scholar for studies related to hormones and jawbone. Search strategies included the combinations ("name of hormone" + "dental term") of the following terms: "hormones", "oxytocin", "estrogen", "adiponectin", "parathyroid hormone", "testosterone", "insulin", "angiotensin", "cortisol", and "erythropoietin", combined with a dental term "jaw bone", "alveolar bone", "dental implant", "jaw + bone regeneration, healing or repair", "dentistry", "periodontitis", "dry socket", "osteoporosis" or "alveolitis". The papers were screened according to the inclusion criteria from January 1, 2000 to March 31, 2021 in English. Publications included reviews, book chapters, and original research papers; in vitro studies, in vivo animal, or human studies, including clinical studies, and meta-analyses.

Results

Bone formation and remodeling is a complex continuous process involving many hormones. Bone volume reduction following tooth extractions and bone diseases, such as periodontitis and osteoporosis, cause serious problems and require a great understanding of the process.

Conclusion

Hormones are with us all the time, shape our development and regulate homeostasis. Newly discovered effects of hormones influencing bone healing open the possibilities of using hormones as therapeutics to combat bone-related diseases.

Can Our Blood Help Ensure Antimicrobial and Anti-Inflammatory Properties in Oral and Maxillofacial Surgery?

In recent decades, the potential of PRF has been extensively studied. The number of studies about PRF has increased three times since the year 2012, but the full spectrum of its fundamental properties, such as antimicrobial and anti-inflammatory activity, is not clearly described. In oral and maxillofacial surgery, PRF is described in alveolar ridge preservation, orthognathic surgery, cleft lip and palate surgery, maxillary sinus augmentation, and dental implant placement as demonstrating favorable results and its clinical advantages. The structural complexity, inhomogeneous nature, and clotting ability of PRF make its antimicrobial effect evaluation complicated. Nevertheless, most of the used antimicrobial testing methods are based on antibacterial agent diffusion ability in culture media. Because the oral and maxillofacial region is the most frequent area of PRF application, its antimicrobial activity evaluation also prevails in the oral microbiome. PRF's biological potential is highly dependent on the specific preparation protocol and methodology used; it should be carefully prepared and kept under proper conditions to keep cellular content alive. PRF's influence on living cells demonstrates a stimulating effect on bone regeneration, and an angiogenetic effect, and it provides anti-inflammatory activity. According to analyzed studies, PRF demonstrated success in oral and maxillofacial surgery in various methods of application. Antibacterial and anti-inflammatory properties were proven by antibacterial activity against different bacterial species, sustained growth factor, sustained release, and cell activity on the material application. Accurately and correctly prepared PRF can ensure antibacterial and anti-inflammatory properties, and it can be a beneficial clinical tool in oral and maxillofacial surgery.

Accuracy and Technical Predictability of Computer Guided Bone Harvesting from the Mandible: A Cone-Beam CT Analysis in 22 Consecutive Patients

This study assesses the accuracy and technical predictability of a computer-guided procedure for harvesting bone from the external oblique ridge using a patient-specific cutting guide. Twenty-two patients needing bone augmentation for implant placement were subjected to mandibular osteotomy employing a case-specific stereolithographic surgical guide generated through computer aided design. Differences between planned and real cut planes were measured comparing pre- and post-operative Cone Beam Computed Tomography images of the donor site according to six validated angular and displacement indexes. Accuracy and technical predictability were assessed for 119 osteotomy planes over the study population. Three different guide fitting approaches were compared. An average root-mean-square discrepancy of 0.52 (0.30-0.97) mm was detected. The accuracy of apical and medial planes was higher than the mesial and distal planes due to occasional antero-posterior guide shift. Fitting the guide with an extra reference point on the closest tooth performed better than using only the bone surface, with two indexes significantly lower and less disperse. The study showed that the surgical plan was actualized with a 1 mm safety margin, allowing effective nerve preservation and reducing technical variability. When possible, surgical guide design should allow fitting on the closest tooth based on both radiological and/or intra-oral scan data.

Autogenous Chin Block Grafts for Implant-Supported Rehabilitation: A 20-Year Follow-Up Case Series

The aim of the present study was to analyze the survival and success rates of dental implants placed in atrophic alveolar ridges reconstructed with mandibular symphysis autogenous onlay bone grafts, with a 20-year follow-up. A sample of five patients referred to the authors' department between 2000 and 2001 seeking for an implant-supported fixed rehabilitation. Patients were treated by means of autogenous bone blocks grafted from the mandibular symphysis and covered with bone substitutes (DBB) and a resorbable membrane. Then delayed implants were placed and finally prosthetic restoration was performed. In total, 10 implants placed in 5 patients were evaluated with a follow-up of 20 years. Both implant survival and success rate were 100%. The mean marginal bone loss was 0.32  [[EQUATION]]  0.39 mm (range 0-1.3 mm). Considering the conditions of peri-implant hard and soft tissues, the diagnosis of peri-implant health was made for all the implants included. According to this study, implants placed in alveolar ridges augmented by means of autogenous chin bone grafts showed long-term survival and high success rates. A correct management of peri-implant soft tissues and an accurate prosthetic rehabilitation are also fundamental to obtain the durable success of the treatment.

Poly(lactic acid/caprolactone) bilayer membrane blocks bacterial penetration

BACKGROUND AND OBJECTIVE

The clinical outcomes of guided tissue regeneration (GTR) or guided bone regeneration (GBR) procedures can be impaired if a bacterial infection develops at the surgical site. Membrane exposure is one of the causes of the onset of bacterial infection. Previously, we have fabricated a poly(lactic acid/caprolactone) (PLCL) bilayer membrane composed of a porous layer and a compact layer. The compact layer acts as a barrier against connective tissue and epithelial cells, and we hypothesized that it could also be an effective barrier against bacterial cells. The objective of this study was to evaluate the ability of the PLCL bilayer membrane to block bacterial cell penetration, which would be useful for preventing postoperative infections.

METHODS

Porphyromonas gingivalis, Streptococcus mutans, and multispecies bacteria collected from human saliva were used in this study. Bacteria were seeded directly on the compact layer of a PLCL bilayer membrane, and bacterial adhesion to the membrane, as well as penetration into the membrane's structure, were assessed. Bacterial adhesion was evaluated by the number of colonies formed at 6, 24, and 72 h, and penetration was observed using a scanning electron microscope at 24 and 72 h. Commercially available membranes, composed of poly(lactic-co-glycolic acid) or type I collagen, were used as controls.

RESULTS

P. gingivalis, S. mutans, and the multispecies bacteria obtained from human saliva adhered onto all the membranes after only 6 h of incubation. However, fewer adherent cells were observed for the PLCL bilayer membrane compared with the controls for all experimental periods. The PLCL membrane was capable of blocking bacterial penetration, and no bacterial cells were observed in the structure. In contrast, bacteria penetrated both the control membranes and were observed at depths of up to 80 µm after 72 h of incubation.

CONCLUSION

Membrane characteristics may influence how bacterial colonization occurs. The PLCL membrane had reduced bacterial adhesion and blocked bacterial penetration, and these characteristics could contribute to a favorable outcome for regenerative treatments. In the event of membrane exposure at GTR/GBR surgical sites, membranes with an efficient barrier function, such as the PLCL bilayer membrane, could simplify the management of GTR/GBR complications.

Complications in bone-grafting procedures: Classification and management

Bone-regenerative interventions aiming to restore deficient alveolar ridges, such as the use of block grafts or through the application of guided bone-regeneration principles, have reported positive outcomes in the published scientific literature. These interventions, however, are invasive, and hence, intraoperative and/or postoperative complications may occur. The types of complications and their severity may vary from the exposure of the biomaterial (membrane or graft) to postsurgical infections, neurosensorial disturbances, occurrence of hemorrhage, and pain, etc. The aim of the present narrative review was to search the available scientific evidence concerning the incidence of these complications, their effect on treatment outcomes, their clinical management and, finally, strategies aimed at prevention. Exposure of the barrier membrane or the block graft is the most common complication associated with oral regenerative interventions. To manage these complications, depending on the extent of the exposure and the presence or absence of concomitant infections, therapeutic measures may vary, from the topical application of antiseptics to the removal of the barrier membrane or the block graft. Regardless of their treatment, the occurrence of these complications has been associated with patient selection, with compliant patients (eg, nonsmokers) having a lower reported incidence of complications. Similarly, surgical factors such as correct flap elevation and a tensionless closure are of obvious importance. Finally, to prevent the incidence of complications, it appears prudent to utilize whenever possible less invasive surgical interventions.

Survival Rates of Dental Implants in Autogenous and Allogeneic Bone Blocks: A Systematic Review

Background and Objectives: Preliminary studies emphasize the similar performance of autogenous bone blocks (AUBBs) and allogeneic bone blocks (ALBBs) in pre-implant surgery; however, most of these studies include limited subjects or hold a low level of evidence. The purpose of this review is to test the hypothesis of indifferent implant survival rates (ISRs) in AUBB and ALBB and determine the impact of various material-, surgery- and patient-related confounders and predictors. Materials and Methods: The national library of medicine (MEDLINE), Excerpta Medica database (EMBASE) and Cochrane Central Register of Controlled Trials (CENTRAL) were screened for studies reporting the ISRs of implants placed in AUBB and ALBB with ≥10 participants followed for ≥12 months from January 1995 to November 2021. The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias was assessed via several scoring tools, dependent on the study design. Means of sub-entities were presented as violin plots. Results: An electronic data search resulted in the identification of 9233 articles, of which 100 were included in the quantitative analysis. No significant difference (p = 0.54) was found between the ISR of AUBB (96.23 ± 5.27%; range: 75% to 100%; 2195 subjects, 6861 implants) and that of ALBB (97.66 ± 2.68%; range: 90.1% to 100%; 1202 subjects, 3434 implants). The ISR in AUBB was increased in blocks from intraoral as compared to extraoral donor sites (p = 0.0003), partially edentulous as compared to totally edentulous (p = 0.0002), as well as in patients younger than 45 as compared to those older (p = 0.044), cortical as compared to cortico-cancellous blocks (p = 0.005) and in delayed implantations within three months as compared to immediate implantations (p = 0.018). The ISR of ALBB was significantly increased in processed as compared to fresh-frozen ALBB (p = 0.004), but also in horizontal as compared to vertical augmentations (p = 0.009). Conclusions: The present findings widely emphasize the feasibility of achieving similar ISRs with AUBB and ALBB applied for pre-implant bone grafting. ISRs were negatively affected in sub-entities linked to more extensive augmentation procedures such as bone donor site and dentition status. The inclusion and pooling of literature with a low level of evidence, the absence of randomized controlled clinical trials (RCTs) comparing AUBB and ALBB and the limited count of comparative studies with short follow-ups increases the risk of bias and complicates data interpretation. Consequently, further long-term comparative studies are needed.

Lateral Alveolar Ridge Augmentation with an Autogenous Bone Block Graft Alone with or without Barrier Membrane Coverage: a Systematic Review and Meta-Analysis

Objectives

To test the hypothesis of no difference in implant treatment outcome following lateral alveolar ridge augmentation with autogenous bone block graft with or without barrier membrane coverage.

Material and Methods

PubMed (MEDLINE), Embase and Cochrane library search in combination with a hand-search of relevant journals was conducted. Human studies published in English until the 8^th of February 2021 were included. Randomised controlled trials with an observation period longer than three months were included. Survival of implants and suprastructures were considered as primary outcomes measures, whereas peri-implant marginal bone loss, dimensional changes of the alveolar ridge, bone regeneration, patient-reported outcome measures, biological and mechanical complications were secondary outcome measures, as evaluated by descriptive statistics and meta-analysis including 95% confidence interval (CI).

Results

Electronic search and hand-searching resulted in 411 entries. Five randomised controlled trials characterised by low or high risk of bias fulfilled inclusion criteria. No statistically significant difference between the two treatment modalities was observed in any of the outcome measures. However, barrier membrane coverage was associated with a non-significant gain in alveolar ridge width of 0.5 mm (95% CI = -0.1 to 1.1) and diminished resorption of -0.9 mm (95% CI = -2.4 to 0.7) compared with no barrier membrane coverage.

Conclusions

Comparable implant treatment outcomes were revealed following lateral alveolar ridge augmentation with autogenous bone block graft alone with or without barrier membrane coverage. However, postoperative dimensional changes of the augmented seems to be diminished with the use of barrier membrane coverage as evaluated by two-dimensional linear measurements.

Evaluation of Resorption and Osseointegration of Autogenous Bone Ring Grafting in Vertical Bone Defect With Simultaneous Implant Placement in Dogs

The aim of this research was to evaluate the resorption and osseointegration of an autogenous bone ring, which was grafted in a local vertical alveolar defect with simultaneous implant placement. Six Beagle dogs were enrolled in the study; their 4 nonadjacent mandibular premolars were extracted, and the buccal plate was removed to create bone defects in 2 of the 4 sites. Three months after extraction, Straumann implants (Ø 3.3 mm, length of 8 mm) were placed in the bone defect sites with simultaneous autogenous bone ring grafting and in the conventional extraction sites. After a 3-month healing period and a 3-month loading period, the animals were euthanized. The harvested samples were analyzed using micro-computed tomography (CT) scanning and histological analysis. From the micro-CT measurements, the average vertical bone resorption of the bone ring was 0.23 ± 0.03 mm, which was not significantly different from that around the conventional implant, 0.24 ± 0.12 mm (P > .05). The ratio of the bone volume to the total volume of the bone ring group was 91.11 ± 0.02, which was higher than that of the control group, 88.38 ± 2.34 (P < .05). From the hard tissue section, the bone rings developed fine osseointegration with the implants and the base alveolar bone. The results suggest autogenous bone ring grafting with simultaneous implant placement can survive in a local vertical bone defect with little bone resorption and good osseointegration in dogs with strict management. A bone ring graft must be compared with guided bone regeneration, and a larger and longer observation must be confirmed in clinical patients.

Comparison of two different biomaterials in the bone regeneration (15, 30 and 60 days) of critical defects in rats

PURPOSE

To evaluate and compare two types of different scaffolds in critical bone defects in rats.

METHODS

Seventy male Wistar rats (280 ± 20 grams) divided into three groups: control group (CG), untreated animals; biomaterial group 1 (BG1), animals that received the scaffold implanted hydroxyapatite (HA)/poly(lactic-co-glycolic) acid (PLGA); and biomaterial group 2 (BG2), animals that received the scaffolds HA/PLGA/Bleed. The critical bone defect was induced in the medial region of the skull calotte with the aid of an 8-mm-diameter trephine drill. The biomaterial was implanted in the form of 1.5 mm thick scaffolds, and samples were collected after 15, 30 and 60 days. Non-parametric Mann-Whitney test was used, with the significance level of 5% (p ≤ 0.05).

RESULTS

Histology revealed morphological and structural differences of the neoformed tissue between the experimental groups. Collagen-1 (Col-1) findings are consistent with the histological ones, in which BG2 presented the highest amount of fibers in its tissue matrix in all evaluated periods. In contrast, the results of receptor activator of nuclear factor kappa-Β ligand (Rank-L) immunoexpression were higher in BG2 in the periods of 30 and 60 days, indicating an increase of the degradation of the biomaterial and the remodeling activity of the bone.

CONCLUSIONS

The properties of the HA/PLGA/Bleed scaffold were superior when compared to the scaffold composed only by HA/PLGA.

Patient- and clinician-reported outcomes for the additively manufactured sub-periosteal jaw implant (AMSJI) in the maxilla: a prospective multicentre one-year follow-up study

The clinical outcomes of maxillary rehabilitation with the additively manufactured sub-periosteal jaw implant (AMSJI; CADskills BV) were evaluated in edentulous patients with a Cawood-Howell atrophy classification ≥5 in all regions of the maxilla. Fifteen consecutive patients were included in the study and followed up for 1 year. They were interviewed using a survey protocol and were examined clinically and radiographically preoperatively (T0) and at 1 (T1), 6 (T2), and 12 (T3) months after permanent upper prosthesis placement. The patients reported an increased oral health-related quality of life. The overall mean Oral Health Impact Profile-14 score at T0 was 17.20 (standard deviation (SD) 6.42). When results at T0 were compared to those at T1 (mean 8.93, SD 5.30), a statistically significant difference was seen (P = 0.001). At T3, the mean value was 5.80 (SD 4.18). Compared to T0, there was also a statistically significant difference at T3 (P = 0.001). General satisfaction based on the numerical rating scale was a mean 49.93 at T1, which was less than patient expectation prior to treatment at T0 (52.13). A higher overall value was seen at T3 (53.20) when compared to T0. Within the constraints of the short follow-up, the AMSJI appears to be a promising tool for patients with extreme jaw atrophy. The high patient expectations were met without complications.

Ibandronate Reduces the Surface Bone Resorption of Mandibular Bone Grafts: A Randomized Trial With Internal Controls

Autologous bone grafts are considered the gold standard for reconstruction of the edentulous alveolar ridges. However, this procedure is associated with unpredictable bone loss caused by physiological bone resorption. Bisphosphonates are antiresorptive drugs that act specifically on osteoclasts, thereby maintaining bone density, volume, and strength. It was hypothesized that the resorption of bone grafts treated with an ibandronate solution would be less advanced than bone grafts treated with saline. Ten patients who underwent bilateral sagittal split osteotomy were included in a randomized double‐blind trial with internal controls. Each patient received a bone graft treated with a solution of ibandronate on one side and a graft treated with saline (controls) contralaterally. Radiographs for the measurement of bone volume were obtained at 2 weeks and at 6 months after surgery. The primary endpoint was the difference in the change of bone volume between the control and the ibandronate bone grafts 6 months after surgery. All of the bone grafts healed without complications. One patient was excluded because of reoperation. In eight of the nine patients, the ibandronate bone grafts showed an increase in bone volume compared with baseline, with an average gain of 126 mm³ (40% more than baseline) with a range of +27 to +218 mm³. Only one ibandronate‐treated graft had a decrease in bone volume (8%). In the controls, an average bone volume loss of −146 mm³ (58% of baseline) with a range of −29 to −301 mm³ was seen. In the maxillofacial field, the reconstructions of atrophic alveolar ridges, especially in the esthetical zones, are challenging. These results show that bone grafts locally treated with ibandronate solution increases the remaining bone volume. This might lead to new possibilities for the maxillofacial surgeons in the preservation of bone graft volumes and for dental implant installations. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

A clinical and radiographic study of implants placed in autogenous bone grafts covered by either a platelet-rich fibrin membrane or deproteinised bovine bone mineral and a collagen membrane: a pilot randomised controlled clinical trial with a 2-year follow-up

Purpose

To compare the survival and clinical performance of implants placed in sites previously augmented with autogenous bone grafts covered by either a platelet-rich fibrin (PRF) membrane (PRF group) or a standard procedure (gold standard) involving coverage of the autogenous bone graft with deproteinised bovine bone mineral and a resorbable collagen membrane (control group).

Methods

A total of 27 partially edentulous patients (test n = 14, control n = 13) with indication for staged lateral bone block augmentation and dental implant placement were included. Twenty-four months after crown placement (range: 14–32 months), patients were recalled for a final clinical and radiographic follow-up. Outcome measures were implant survival, implant crown survival, clinical parameters of the implant, peri-implant marginal bone level, marginal bone level of adjacent tooth surfaces, biological and technical complications and patient-related outcome measures.

Results

Two implants were lost in the control group (85% survival rate); none were lost in the PRF group (100% survival rate). None of the 26 initially placed implant crowns were lost, but one implant and therefore one implant crown were lost after 20 months. Consequently, the definitive implant crown survival was 92% (95% confidence interval (CI): 73–110%) in the control group and 100% in the PRF group. No statistical difference in implant survival rate (p = 0.13) or implant crown survival was seen between the groups (p = 0.28). The mean marginal bone level at the follow-up was 0.26 mm (95% CI: 0.01–0.50 mm) in the PRF group and 0.68 mm (95% CI: 0.41–0.96 mm) in the control group. The difference between the groups was − 0.43 mm (95% CI: − 0.80 to − 0.05 mm, p = 0.03), which was statistically significant (p = 0.03). Both groups demonstrated similar healthy peri-implant soft tissue values at the final follow-up.

Conclusion

Although the current study is based on a small sample of participants, the findings suggest that the methodology of the PRF and the control group approach can both be used for bone augmentation with a similar outcome. A significant, but clinically irrelevant, higher peri-implant marginal bone level was registered in the PRF group than in the control group. Patients in both groups were highly satisfied with the treatment.

Trial registration

ClinicalTrials.gov Identifier: NCT04350749. Registered 17 April 2020. Retrospectively registered.

Clinical and histological sequelae of surgical complications in horizontal guided bone regeneration: a systematic review and proposal for management

It is not uncommon to encounter post-surgical complications after horizontal guided bone regeneration (GBR). The primary aim of this review was to evaluate the incidence and types of complications that occur after horizontal GBR and propose management strategies to deal with these clinical situations. A secondary aim was to conduct a histomorphometric review of the wound healing process at sites that experienced post-surgical complications after GBR. A keyword search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for studies published in English from January 2015 to January 2020 was conducted for the primary aim and 23 studies were selected. A second search addressing the secondary aim was conducted, and five studies were included. Site-level analysis showed that the weighted mean incidence proportion of minor wound dehiscence and minor infections occurring at the augmented site was 9.9% [95% CI 6.4, 13.9, P < 0.01] and 1.5% [95% CI 0.4, 3.1, P = 0.21) respectively. Patient-level analysis showed minor and major complications occurring at a weighted mean incidence proportion of 16.1% [95% CI 11.9, 20.8, P = 0.01] and 1.6% [95% CI 0.0, 4.7, P < 0.01] respectively, while neurosensory alterations at the donor site was 7.0% [95% CI 1.3, 15.5, P < 0.01]. Subgroup analysis also revealed that the use of block grafts increased the incidence proportion of minor post-surgical complications, whereas a staged GBR procedure increased the incidence proportion of both minor and major post-surgical complications. Although exposure of the barrier membrane is often associated with less bone regeneration and graft resorption, the type of membrane used (resorbable or non-resorbable) had no statistically significant influence on any post-surgical complication. Histologically, a layer of fibrous connective tissue instead of bone is commonly observed at the interface between the native bone at the recipient site and the regenerated bone in cases with membrane exposure after GBR procedure. Minor wound dehiscence was the highest incidence proportion of post-surgical complications. Methods ranging from daily application of antiseptics, use of systemic antimicrobials, regular reviews, and total removal of the non-integrated biomaterials are commonly prescribed to manage these post-surgical complications in attempt to minimise the loss of tissue at the surgical site.

Distinct Osteogenic Potentials of BMP-2 and FGF-2 in Extramedullary and Medullary Microenvironments

Bone morphogenetic protein-2 (BMP-2) and fibroblast growth factor-2 (FGF-2) have been regarded as the major cytokines promoting bone formation, however, several studies have reported unexpected results with failure of bone formation or bone resorption of these growth factors. In this study, BMP-2 and FGF-2 adsorbed into atellocollagen sponges were transplanted into bone defects in the bone marrow-scarce calvaria (extramedullary environment) and bone marrow-abundant femur (medullary environment) for analysis of their in vivo effects not only on osteoblasts, osteoclasts but also on bone marrow cells. The results showed that BMP-2 induced high bone formation in the bone marrow-scarce calvaria, but induced bone resorption in the bone marrow-abundant femurs. On the other hand, FGF-2 showed opposite effects compared to those of BMP-2. Analysis of cellular dynamics revealed numerous osteoblasts and osteoclasts present in the newly-formed bone induced by BMP-2 in calvaria, but none were seen in either control or FGF-2-transplanted groups. On the other hand, in the femur, numerous osteoclasts were observed in the vicinity of the BMP-2 pellet, while a great number of osteoblasts were seen near the FGF-2 pellets or in the control group. Of note, FCM analysis showed that both BMP-2 and FGF-2 administrated in the femur did not significantly affect the hematopoietic cell population, indicating a relatively safe application of the two growth factors. Together, these results indicate that BMP-2 could be suitable for application in extramedullary bone regeneration, whereas FGF-2 could be suitable for application in medullary bone regeneration.

Autogenous bone augmentation from the zygomatic alveolar crest: a volumetric retrospective analysis in the maxilla

BACKGROUND

Autogenous bone augmentation is the gold standard for the treatment of extended bone defects prior to implantation. Bone augmentation from the zygomatic crest is a valuable option with several advantages, but the current literature for this treatment is scant. The aim of this study was to evaluate the increase in bone volume after locoregional bone augmentation using autogenous bone from the zygomatic alveolar crest as well as the complications and success rate.

RESULTS

Analysis of the augmented bone volume in seven patients showed a maximum volume gain of 0.97 cm³. An average of 0.54 cm³ of autogenous bone (SD 0.24 cm³; median: 0.54 cm³) was augmented. Implantation following bone augmentation was possible in all cases. Complications occurred in three patients.

CONCLUSION

The zygomatic alveolar crest is a valuable donor site for autogenous alveolar onlay grafting in a locoregional area such as the maxillary front. Low donor site morbidity, good access, and its suitable convexity make it a beneficial choice for autogenous bone augmentation.

The use of additively manufactured scaffolds for treating gingival recession associated with interproximal defects

Gingival recessions are a highly prevalent issue that is often associated with interproximal tissue deficiency. An intervention in these scenarios is of extreme importance since these defects can lead to aesthetic, phonetic and other dental problems. Unfortunately, the treatment of advanced gingival recessions is a major challenge in periodontics because of its unpredictability. In such cases, the use of injectable fillings, connective tissue grafts or bone grafts for vertical regeneration in interproximal area presents limited results. Considering that, this special report reviewed the possible use of additively manufactured scaffolds as a therapeutic option. A 3D-printed personalized therapy is expected to simplify the regeneration of interproximal area, enabling bone regeneration, new papilla formation and root coverage.

Development prospects of curable osteoplastic materials in dentistry and maxillofacial surgery

The article presents classification of the thermosetting materials for bone augmentation. The physical, mechanical, biological, and clinical properties of such materials are reviewed. There are two main types of curable osteoplastic materials: bone cements and hydrogels. Compared to hydrogels, bone cements have high strength features, but their biological properties are not ideal and must be improved. Hydrogels are biocompatible and closely mimic the extracellular matrix. They can be used as cytocompatible scaffolds for tissue engineering, as can protein- and nucleic acid-activated structures. Hydrogels may be impregnated with osteoinductors such as proteins and genetic vectors without conformational changes. However, the mechanical properties of hydrogels limit their use for load-bearing bone defects. Thus, improving the strength properties of hydrogels is one of the possible strategies to achieve the basis for an ideal osteoplastic material.

Autogenous Chin Block Grafts in the Aesthetic Zone: A 20-Year Follow-Up Case Report

The successful use of osseointegrated implants in the treatment of partial or complete edentulism requires a sufficient bone support. Whenever rehabilitation in atrophic edentulous areas is needed, bone augmentation procedures are recommended. The aim is to provide adequate amount of supporting bone to achieve a prosthetically guided implant placement. This in turn leads to functional and aesthetic improvements that can be maintained on the long term. Bone grafting of the atrophic site can be performed either prior to implant placement or at the time of implantation. Irrespective of the timing, bone augmentation by means of autogenous bone grafts is a reliable technique, as confirmed by several studies. On the other hand, long-term evidence on the use of autogenous chin block grafts in preprosthetic implant surgery is still scarce. Thus, the purpose of the present case is to report the 20-year clinical and radiological outcome of autogenous chin block grafts used to augment a bilateral defect due to agenesis of the upper lateral incisors for implant placement purposes.

Supplemental periodontal regeneration by vertical ridge augmentation around dental implants. A preclinical in vivo experimental study

OBJECTIVES

To evaluate the supplemental periodontal regeneration on adjacent teeth by vertical ridge augmentation around dental implants.

MATERIAL AND METHODS

The second premolar and the fourth premolar were extracted from both sides of the mandible in four beagle dogs. After 2 months, defects of 3 mm and 5 mm deep were formed. In the test group, vertical ridge augmentation was performed around a dental implant, and in the control group, vertical ridge augmentation was performed without implant placement. The animals were euthanized 3 months after the procedure, and radiographic and histomorphometric analyses were performed.

RESULTS

Overall, the test group showed better results than the control group. The presence of new cementum in the histological examination of the test group confirmed that vertical ridge augmentation with proper space maintaining could contribute to periodontal regeneration of adjacent teeth. Statistically significant difference in new bone height (%) was found in group I (5-mm defect depth and implant placement, GBR) when compared with group III (5-mm defect depth, GBR) and IV (3-mm defect depth, GBR). New bone area (%) was statistically different between groups I and IV.

CONCLUSIONS

In conclusion, within the limitation of this study using mandibular residual ridges after extraction of a single tooth in dogs, grafted space was maintained by dental implants better in the deep defect (5-mm depth) than the shallow defect (3-mm depth). Vertical ridge augmentation around dental implants also promoted neighboring periodontal regeneration.

Effect of GARP on osteogenic differentiation of bone marrow mesenchymal stem cells via the regulation of TGFβ1 in vitro

Mesenchymal stem cells (MSCs), which have multipotential differentiation and self-renewal potential, are possible cells for tissue engineering. Transforming growth factor β1 (TGFβ1) can be produced by MSCs in an inactive form, and the activation of TGFβ1 functions as an important regulator of osteogenic differentiation in MSCs. Recently, studies showed that Glycoprotein A repetitions predominant (GARP) participated in the activation of latent TGFβ1, but the interaction between GARP and TGFβ1 is still undefined. In our study, we successfully isolated the MSCs from bone marrow of rats, and showed that GARP was detected in bone mesenchymal stem cells (BMSCs). During the osteogenic differentiation of BMSCs, GARP expression was increased over time. To elucidate the interaction between GARP and TGFβ1, we downregulated GARP expression in BMSCs to examine the level of active TGFβ1. We then verified that the downregulation of GARP decreased the secretion of active TGFβ1. Furthermore, osteogenic differentiation experiments, alkaline phosphatase (ALP) activity analyses and Alizarin Red S staining experiments were performed to evaluate the osteogenic capacity. After the downregulation of GARP, ALP activity and Alizarin Red S staining significantly declined and the osteogenic indicators, ALP, Runx2, and OPN, also decreased, both at the mRNA and protein levels. These results demonstrated that downregulated GARP expression resulted in the reduction of TGFβ1 and the attenuation of osteoblast differentiation of BMSCs in vitro.

Histologic and histomorphometric evaluation of the bone regeneration following cortical bone repositioning in a rabbit mandible

BACKGROUND

Although bone graft (BG) is the gold standard for bone augmentation, its use is hampered by donor site morbidity and limited quantity.

PURPOSE

To evaluate the capabilities of bone formation by cortical bone repositioning (CBR) as the healing response following grafting of autogenous bone block without filling biomaterial at the gap between gap and recipient.

MATERIALS AND METHODS

Twelve Japanese White rabbits were divided into three groups (postoperative 2, 5, and 8 weeks). A cortical block was freed from the mandibular body, half of the block was positioned and fixed overlapped the original bone surface beside the defect and the other half remained only elevated above the defect. Three areas were decided for the evaluation; BG, CBR, and defect (D) area. Areas were evaluated by micro-CT, histology, and histomorphometric analysis.

RESULTS

There is no statistical difference between BG and CBR by evaluating distance and area in histomorphometrical analysis (P < .05). D area showed statistical decrease compared with BG and CBR at week 2. Histologically, new bone was evident at week 2, mature bone was observed in all three areas at week 8, D area disappeared and fused completely with the elevated bone block.

CONCLUSION

CBR has potential for bone augmentation as BG induced from its own regenerative ability of healing process.

Influence of experimental alcoholism on the repair process of bone defects filled with beta-tricalcium phosphate

This study evaluated the effect of ethanol on the repair in calvaria treated with beta-tricalcium phosphate (β-TCP). Forty rats were distributed into 2 groups: Water group (CG, n = 20) and Alcohol Group (AG, n = 20), which received 25% ethanol ad libitum after an adaptation period of 3 weeks. After 90 days of liquid diet, the rats were submitted to a 5.0 mm bilateral craniotomy in the parietal bones; the left parietal was filled with β-TCP (CG-TCP and AG-TCP) and the contralateral only with blood clot (CG-Clot and AG-Clot). The animals were killed after 10, 20, 40 and 60 days. The groups CG-Clot and AG-Clot showed similar pattern of bone formation with a gradual and significant increase in the amount of bone in CG-Clot (22.17 ± 3.18 and 34.81 ± 5.49) in relation to AG-Clot (9.35 ± 5.98 and 21.65 ± 6.70) in periods of 20-40 days, respectively. However, in the other periods there was no statistically significant difference. Alcohol ingestion had a negative influence on bone formation, even with the use of β-TCP, exhibiting slow resorption and replacement by fibrous tissue, with 16% of bone formation within 60 days in AG-TCP, exhibiting immature bone tissue with predominance of disorganized collagen fibers. Defects in CG-TCP showed bone tissue with predominance of lamellar arrangement filling 39% of the original defect. It can be concluded that chronic ethanol consumption impairs the ability to repair bone defects, even with the use of a β-TCP biomaterial.

Clinical Classification of Bone Augmentation Procedure Failures in the Atrophic Anterior Maxillae: Esthetic Consequences and Treatment Options

Although the number of complications and failures in bone augmentation procedures is still relatively high, these problems remain poorly documented. Moreover, the literature concerning reconstructive techniques and the treatment of their complications in the anterior areas rarely considers the final esthetic result. The aim of this paper is to propose a new classification of bone augmentation complications in the esthetic area, providing treatment guidelines useful for the management of these cases. Failures of bony regeneration procedures can be mainly divided into partial failures and complete failures. A partial failure can be solved with a corrective surgical intervention: this second surgery can have success or may not be able to provide the desired esthetic result. When the bone reconstructive procedure fails totally, a complete failure occurs and the whole procedure has to be repeated. This new intervention can have success but also this new reconstructive surgery can fail in the same way as the first, causing important damage and a compromise solution that will hardly be acceptable from an esthetic point of view. Bone augmentation techniques are not completely predictable and are not always able to guarantee the expected result, especially in the atrophic anterior maxilla. Complications and failures can often occur and this possibility must always be clearly explained to those patients with high esthetic demands and expectations.

Comparison of Bone Grafts From Various Donor Sites in Human Bone Specimens

The objective of the current study was to compare the three-dimensional (3D) morphometric microstructure in human cadaveric bone specimens taken from various commonly utilized donor sites for autogenous bone grafting. Autogenous bone grafts can be harvested from various anatomic sites and express heterogeneous bone quality with a specific 3D microstructure for each site. The long-term structural integrity and susceptibility to resorption of the graft depend on the selected donor bone. Micro-computed tomography generates high-resolution datasets of bone structures and calcifications making this modality versatile for microarchitecture analysis and quantification of the bone. Six bone specimens, 10 mm in length, where anatomically possible, were obtained from various anatomical sites from 10 human dentate cadavers (4 men, 6 women, mean age 69.5 years). Specimens were scanned using a micro-computed tomography device and volumetrically reconstructed. A virtual cylindrical inclusion was reconstructed to analyze the bone mineral density and structural morphometric analysis using bone indices: relative bone volume, surface density, trabecular thicknesses, and trabecular separation. Calvarial bone specimens showed the highest mineral density, followed by the chin, then mandibular ramus then the tibia, whereas iliac crest and maxillary tuberosity had lower bone mineral densities. The pairwise comparison revealed statistically significant differences in the bone mineral density and relative bone volume index in the calvaria, mandibular ramus, mandibular symphysis groups when compared with those in the iliac crest and maxillary tuberosity, suggesting higher bone quality in the former groups than in the latter; tibial specimens expressed variable results.

Feasibility of a combination of intraoral UHFUS and CBCT in the study of peri-implantitis

OBJECTIVES

The aim of this study was to investigate the combination of intraoral ultra-high-frequency ultrasonography (UHFUS) and cone beam computed tomography (CBCT) in the evaluation of hard and soft tissues in a case of peri-implantitis.

STUDY DESIGN

A 57-year-old patient was referred for pain and numbness of the chin after implant placement and the subsequent guided bone regeneration (GBR) procedure. Clinical examination revealed hard tumefaction of the mandibular mucosa, with mild mobility of the implants. Assessment with UHFUS was undertaken for the study of the width, degree of tissue alteration, and vascularity of the swollen mucosa, and CBCT was used to evaluate the bone surrounding the implants and the possible impingement of the inferior alveolar nerve.

RESULTS

A combination of CBCT and UHFUS was effective in the evaluation of GBR complications in peri-implantitis, revealing alterations in the periosteum secondary to suboptimal GBR treatment. This was the first study to use UHFUS to evaluate the characteristics of oral soft tissues.

CONCLUSIONS

UHFUS is a promising tool for the diagnosis of complicated soft tissue diseases. When used with CBCT, it can provide useful information on oral and maxillofacial diseases involving hard and soft tissue in a noninvasive way, with reduced radiation dose exposure.

Case Report: Managing the postoperative exposure of a non-resorbable membrane surgically

Alveolar ridge deformities can be caused by several factors. Managing alveolar deformities prior to implant placement is essential to increase bone width, height or both. Several techniques and materials are now available to perform ridge augmentation procedures. The postoperative exposure of the membrane is the most frequent postoperative complications of ridge augmentation procedures. The present case describes the horizontal ridge augmentation procedure and the outcome of surgical attempt to manage post-operative membrane exposure, and shows the unpredictability of managing postoperative membrane exposure surgically.

Cell therapy induced regeneration of severely atrophied mandibular bone in a clinical trial

Background

Autologous grafting, despite some disadvantages, is still considered the gold standard for reconstruction of maxillofacial bone defects. The aim of this study was to evaluate bone regeneration using bone marrow-derived mesenchymal stromal cells (MSCs) in a clinical trial, a less invasive approach than autologous bone grafting. This comprehensive clinical trial included subjects with severe mandibular ridge resorption.

Methods

The study included 11 subjects aged 52–79 years with severe mandibular ridge resorption. Bone marrow cells were aspirated from the posterior iliac crest and plastic adherent cells were expanded in culture medium containing human platelet lysate. The MSCs and biphasic calcium phosphate granules as scaffolds were inserted subperiosteally onto the resorbed alveolar ridge. After 4–6 months of healing, new bone formation was assessed clinically and radiographically, as were safety and feasibility. Bone at the implant site was biopsied for micro-computed topography and histological analyses and dental implants were placed in the newly regenerated bone. Functional outcomes and patient satisfaction were assessed after 12 months.

Results

The bone marrow cells, expanded in vitro and inserted into the defect together with biphasic calcium phosphate granules, induced significant new bone formation. The regenerated bone volume was adequate for dental implant installation. Healing was uneventful, without adverse events. The patients were satisfied with the esthetic and functional outcomes. No side effects were observed.

Conclusions

The results of this comprehensive clinical trial in human subjects confirm that MSCs can successfully induce significant formation of new bone, with no untoward sequelae. Hence, this novel augmentation procedure warrants further investigation and may form the basis of a valid treatment protocol, challenging the current gold standard.

Trial registration

EudraCT, 2012-003139-50. Registered on 21 August 2013. ClinicalTrials.gov, NCT 02751125. Registered on 26 April 2016.

Tunnel Access for Guided Bone Regeneration in the Maxillary Anterior

INTRODUCTION

Minimally invasive surgical techniques in periodontics, including methods for ridge augmentation, have been shown to achieve surgical goals while minimizing swelling, decreasing postoperative discomfort, and enhancing soft tissue architecture. The present case illustrates a minimally invasive guided bone regeneration technique for augmentation of a deficient alveolar ridge in the esthetic zone.

CASE PRESENTATION

A 30-year-old patient received localized ridge augmentation utilizing tunnel access for guided bone regeneration with a dense polytetrafluoroethylene membrane and a freeze-dried bone allograft. The patient experienced minimal postoperative swelling and discomfort, and the procedure resulted in favorable ridge dimensions for implant placement.

CONCLUSIONS

The tunnel access for guided bone regeneration presented in this case may offer advantages similar to other minimally invasive ridge augmentation techniques. Further controlled clinical study is warranted.

Bone regeneration using composite non-demineralized xenogenic dentin with beta-tricalcium phosphate in experimental alveolar cleft repair in a rabbit model

Background

Alveolar cleft repair is performed via bone grafting procedure to restore the dental arch continuity. A suitable bone substitute materials should possess osteoinductive and osteoconductive properties, to promote new bone formation, along with a slowly resorbable scaffold that is subsequently replaced with functionally viable bone. Calcium phosphate biomaterials have long proved their efficacy as bone replacement materials. Dentin in several forms has also demonstrated its possibility to be used as bone graft replacement material in several studies. The purpose of this study was to evaluate bone regeneration pattern and quantify bone formation after grafting pre-established experimental alveolar clefts defects model in rabbits using composite xenogenic dentin and β-TCP in comparison to β-TCP alone.

Methods

Unilateral alveolar cleft defects were created in 16 New Zealand rabbits according to previously described methodology. Alveolar clefts were allowed 8 weeks healing period. 8 defects were filled with β-TCP, whereas 8 defects filled with composite xenogenic dentin with β-TCP. Bone regeneration of the healed defects was compared at the 8 weeks after intervention. Quantification of bone formation was analyzed using micro-computed tomography (µCT) and histomorphometric analysis.

Results

µCT and histomorphometric analysis revealed that defects filled with composite dentin/β-TCP showed statistically higher bone volume fraction, bone mineral density and percentage residual graft volume when compared to β-TCP alone. An improved surgical handling of the composite dentin/β-TCP graft was also noted.

Conclusions

Composite xenogenic dentin/β-TCP putty expresses enhanced bone regeneration compared to β-TCP alone in the reconstruction of rabbit alveolar clefts defects.

Autogenous bone grafts in oral implantology-is it still a "gold standard"? A consecutive review of 279 patients with 456 clinical procedures

Background

This study assessed the clinical outcomes of graft success rate and early implant survival rate after preprosthetic alveolar ridge reconstruction with autologous bone grafts.

Methods

A consecutive retrospective study was conducted on all patients who were treated at the military outpatient clinic of the Department of Oral and Plastic Maxillofacial Surgery at the military hospital in Ulm (Germany) in the years of 2009 until 2011 with autologous bone transplantation prior to secondary implant insertion. Intraoral donor sites (crista zygomatico-alveolaris, ramus mandible, symphysis mandible, and anterior sinus wall) and extraoral donor site (iliac crest) were used. A total of 279 patients underwent after a healing period of 3–5 months routinely computer tomography scans followed by virtual implant planning. The implants were inserted using guided oral implantation as described by Naziri et al. All records of all the consecutive patients were reviewed according to patient age, history of periodontitis, smoking status, jaw area and dental situation, augmentation method, intra- and postoperative surgical complications, and surgeon’s qualifications. Evaluated was the augmentation surgical outcome regarding bone graft loss and early implant loss postoperatively at the time of prosthodontic restauration as well a follow-up period of 2 years after loading.

Results

A total of 279 patients underwent 456 autologous augmentation procedures in 546 edentulous areas. One hundred thirteen crista zygomatico-alveolaris grafts, 104 ramus mandible grafts, 11 symphysis grafts, 116 grafts from the anterior superior iliac crest, and 112 sinus lift augmentations with bone scrapes from the anterior facial wall had been performed. There was no drop out or loss of follow-up of any case that had been treated in our clinical center in this 3-year period. Four hundred thirty-six (95.6%) of the bone grafts healed successfully, and 20 grafts (4.4%) in 20 patients had been lost. Fourteen out of 20 patients with total graft failure were secondarily re-augmented, and six patients wished no further harvesting procedure. In the six patients, a partial graft resorption was detected at the time of implantation and additional simultaneous augmentation during implant insertion was necessary. No long-term nerve injury occurred. Five hundred twenty-five out of 546 initially planned implants in 259 patients could be inserted into successfully augmented areas, whereas 21 implants in 20 patients due to graft loss could not be inserted. A final rehabilitation as preplanned with dental implants was possible in 273 of the 279 patients. The early implant failure rate was 0.38% concerning two out of the 525 inserted implants which had to be removed before the prosthodontic restoration. Two implants after iliac crest augmentation were lost within a period of 2 years after loading, concerning a total implant survival rate after 2 years of occlusal loading rate of 99.6% after autologous bone augmentation prior to implant insertion.

Conclusions

This review demonstrates the predictability of autologous bone material in alveolar ridge reconstructions prior to implant insertion, independent from donor and recipient site including even autologous bone chips for sinus elevation. Due to the low harvesting morbidity of autologous bone grafts, the clinical results of our study indicate that autologous bone grafts still remain the “gold standard” in alveolar ridge augmentation prior to oral implantation.