Selection of Collagen Membranes for Bone Regeneration: A Literature Review

Several treatment modalities have been proposed to regenerate bone, including guided bone regeneration (GBR) where barrier membranes play an important role by isolating soft tissue and allowing bone to grow. Not all membranes biologically behave the same way, as they differ from their origin and structure, with reflections on their mechanical properties and on their clinical performance. Collagen membranes have been widely used in medicine and dentistry, because of their high biocompatibility and capability of promoting wound healing. Recently, collagen membranes have been applied in guided bone regeneration with comparable outcomes to non-resorbable membranes. Aim of this work is to provide a review on the main features, application, outcomes, and clinical employment of the different types of collagen membranes. Comparisons with non-resorbable membranes are clarified, characteristics of cross-linked collagen versus native collagen, use of different grafting materials and need for membrane fixation are explored in order to gain awareness of the indications and limits and to be able to choose the right membrane required by the clinical condition.

Bone grafts in craniofacial surgery

Reconstruction of cranial and maxillofacial defects is a challenging task. The standard reconstruction method has been bone grafting. In this review, we shall describe the biological principles of bone graft healing, as pertinent to craniofacial reconstruction. Different types and sources of bone grafts will be discussed, as well as new methods of bone defect reconstruction.

Long-term effectiveness of maxillary sinus floor augmentation: A systematic review and meta-analysis

AIM

To assess the long-term effectiveness (≥5 years) of maxillary sinus floor augmentation (MSFA) procedures applying the lateral window technique and to determine possible differences in outcome between simultaneous and delayed implant placement, partially and fully edentulous patients and grafting procedures.

MATERIALS AND METHODS

MEDLINE (1950-May 2018), EMBASE (1966-May 2018) and Cochrane Central Register of Controlled Trials (1800-May 2018) were searched. Inclusion criteria were prospective studies with follow-up ≥5 years and a residual bone height ≤6 mm. Outcome measures included implant loss, peri-implant bone level change, suprastructure survival, patient-reported outcome measures and overall complications. Data were pooled and analysed using a random effects model.

RESULTS

Out of 2,873 selected articles, 11 studies fulfilled all inclusion criteria. Meta-analysis revealed a weighted annual implant loss of 0.43% (95% CI: 0.37%-0.49%). Meta-regression analysis did not reveal significant differences in implant loss neither between edentulous and dentate patients nor implants placed simultaneously with or delayed after MSFA, nor implants placed in MSFA using solely autologous bone or bone substitutes. The results of the other outcome measures were favourable, and overall complications were low.

CONCLUSION

MSFA is a reliable procedure in the partially and fully edentulous maxilla for support of dental implants.

Evaluation of complication rates and vertical bone gain after guided bone regeneration with non-resorbable membranes versus titanium meshes and resorbable membranes. A randomized clinical trial

Background

The partial edentulous posterior mandible is often a challenge area that requires a bone reconstructive surgery for implants placement.

Purpose

This RCT was aimed to evaluate complications rate and vertical bone gain after Guided Bone Regeneration (GBR) with dense non‐resorbable d‐PTFE titanium‐reinforced membranes (Group A) versus titanium meshes covered by cross‐linked collagen membranes (Group B).

Material and Methods

40 partially edentulous patients with atrophic posterior mandible, were randomly divided into two study group: 20 patients were treated with one stage GBR by means of non‐resorbable d‐PTFE titanium‐reinforced membranes (Group A); and 20 patients, by means of titanium mesh covered by cross‐linked collagen membranes (Group B). All complications were recorded, distinguishing between “surgical” and “healing” and between “minor” or “major.”. Primary implants stability and vertical bone gain were also evaluated.

Results

In the group A, surgical and healing complication rates were 5.0% and 15.0%, respectively. In the group B, surgical and healing complication rates were 15.8% and 21.1%, respectively. No significant differences between two study group were observed regarding complications rate implant stability and vertical bone gain.

Conclusions

Both GBR approaches for the restoration of atrophic posterior mandible achieved similar results regarding complications, vertical bone gain and implant stability.

Regeneration of alveolar ridge defects. Consensus report of group 4 of the 15th European Workshop on Periodontology on Bone Regeneration

BACKGROUND AND AIMS

Bone augmentation procedures to enable dental implant placement are frequently performed. The remit of this working group was to evaluate the current evidence on the efficacy of regenerative measures for the reconstruction of alveolar ridge defects.

MATERIAL AND METHODS

The discussions were based on four systematic reviews focusing on lateral bone augmentation with implant placement at a later stage, vertical bone augmentation, reconstructive treatment of peri-implantitis associated defects, and long-term results of lateral window sinus augmentation procedures.

RESULTS

A substantial body of evidence supports lateral bone augmentation prior to implant placement as a predictable procedure in order to gain sufficient ridge width for implant placement. Also, vertical ridge augmentation procedures were in many studies shown to be effective in treating deficient alveolar ridges to allow for dental implant placement. However, for both procedures the rate of associated complications was high. The adjunctive benefit of reconstructive measures for the treatment of peri-implantitis-related bone defects has only been assessed in a few RCTs. Meta-analyses demonstrated a benefit with regard to radiographic bone gain but not for clinical outcomes. Lateral window sinus floor augmentation was shown to be a reliable procedure in the long term for the partially and fully edentulous maxilla.

CONCLUSIONS

The evaluated bone augmentation procedures were proven to be effective for the reconstruction of alveolar ridge defects. However, some procedures are demanding and bear a higher risk for post-operative complications.

Four modalities of single implant treatment in the anterior maxilla: a clinical, radiographic, and aesthetic evaluation

PURPOSE

To document the outcome of single implants in the anterior maxilla following four routine treatment modalities when performed by experienced clinicians in daily practice using the same implant system and biomaterials.

MATERIAL AND METHODS

A retrospective study in patients who had been treated by two periodontists and two prosthodontists in 2006 and 2007 was conducted. The four treatment modalities practically covered every clinical situation and included standard implant treatment (SIT), immediate implant treatment (IIT), implant treatment in conjunction with guided bone regeneration (GBR), and implant treatment in grafted bone (BGR) harvested from the chin. All implants were installed via flap surgery. Patients were clinically and radiographically examined. Complications were registered and the aesthetic outcome (pink esthetic score [PES] and white esthetic score [WES]) was rated. A blinded clinician who had not been involved in the treatment performed all evaluations. Patient's aesthetic satisfaction was also registered.

RESULTS

One hundred four out of 115 eligible patients (44 SIT, 28 IIT, 18 GBR, and 14 BGR) received at least one single NobelReplace tapered TiUnite® (Nobel Biocare, Göteborg, Sweden) implant in the anterior maxilla and were available for evaluation. Clinical parameters (implant survival: 93%, mean plaque level: 24%, mean bleeding on probing: 33%, and mean probing depth: 3.2 mm) and mean bone level (1.19 mm) did not differ significantly between treatment modalities. Postoperative complications were more common following GBR/BGR (>61%) when compared with SIT/IIT (<18%) (p < .001). BGR was in 4/14 patients associated with permanent sensory complications at the donor site. Technical complications occurred in 9/104 patients. SIT and IIT showed similar soft tissue aesthetics (PES: 10.07 and 10.88, respectively), however major alveolar process deficiency was common (>15%). PES was 9.65 for GBR. BGR showed inferior soft tissue aesthetics (PES: 9.00; p = .045) and shorter distal papillae were found following GBR/BGR (p = .009). Periodontal disease (odds ratio [OR]: 13.0, p < .001), GBR/BGR (OR: 4.3, p = .004), and a thin-scalloped gingival biotype (OR: 3.7, p = .011) increased the risk for incomplete distal papillae. WES was 7.98 for all patients considered. Poor agreement was found between objective and subjective aesthetic ratings.

CONCLUSIONS

All treatment modalities were predictable from a clinical and radiographic point of view. However, advanced reconstructive surgery, especially BGR, increased the risk for complications and compromised aesthetics. Research is required on the prevention and minimally invasive treatment of buccal bone defects at the time of tooth loss to avoid complex therapy.

Alveolar ridge augmentation with titanium mesh. A retrospective clinical study

An adequate amount of bone all around the implant surface is essential in order to obtain long-term success of implant restoration. Several techniques have been described to augment alveolar bone volume in critical clinical situations, including guided bone regeneration, based on the use of barrier membranes to prevent ingrowth of the epithelial and gingival connective tissue cells. To achieve this goal, the use of barriers made of titanium micromesh has been advocated. A total of 13 patients were selected for alveolar ridge reconstruction treatment prior to implant placement. Each patient underwent a tridimensional bone augmentation by means of a Ti-mesh filled with intraoral autogenous bone mixed with deproteinized anorganic bovine bone in a 1:1 ratio. Implants were placed after a healing period of 6 months. Panoramic x-rays were performed after each surgical procedure and during the follow-up recalls. Software was used to measure the mesial and the distal peri-implant bone loss around each implant. The mean peri-implant bone loss was 1.743 mm on the mesial side and 1.913 mm on the distal side, from the top of the implant head to the first visible bone-implant contact, at a mean follow-up of 88 months. The use of Ti-mesh allows the regeneration of sufficient bone volume for ideal implant placement. The clinical advantages related to this technique include the possibility of correcting severe vertical atrophies associated with considerable reductions in width and the lack of major complications if soft-tissue dehiscence and mesh exposures do occur.

Dimensional changes of the maxillary sinus following tooth extraction in the posterior maxilla with and without socket preservation

BACKGROUND

Sinus pneumatization is commonly observed following tooth extraction in the posterior maxilla, however, the role of this pneumatization in the overall changes in the vertical bone height is not clear.

PURPOSE

To compare dimensional changes in the alveolar ridge and corresponding maxillary sinus following tooth extraction, with or without socket preservation.

MATERIALS AND METHODS

42 patients underwent tooth extraction (control group) and 21 patients underwent tooth extraction with socket preservation using DBBM (study group). Panoramic radiographs, prior to and approximately 1 year post extractions were superimposed and matched using a fixed reference unit. The following measurements were performed in the midline of the tooth site: distance of the bone crest to the sinus floor; distance of the sinus floor to the sinus roof and the sagittal circumference of the maxillary.

RESULTS

The mean change in the distance from the sinus floor to the sinus roof pre and post operatively was 0.30 mm (±0.10 SE) in the study group and 1.30 mm (±0.27 SE) in the control group (P = .0221). The mean change in the distance from the bone crest to the sinus floor was 0.32 mm (±0.09 SE) in the study group and 1.26 mm (±0.28 SE) in the control group (P = .0019), and the mean change in the sinus sagittal circumference was 37.34 mm (±6.10 SE) and 125.95 mm (±15.60 SE), respectively (P = .0001).

CONCLUSIONS

Ridge preservation using bovine derived xenograft might reduce sinus pneumatization along with minimizing crestal bone resorption.

Guided Bone Regeneration for the Reconstruction of Alveolar Bone Defects

BACKGROUND

Guided bone regeneration (GBR) is the most common technique for localized bone augmentation.

PURPOSE

The purpose of this review was to categorize and assess various GBR approaches for the reconstruction of human alveolar bone defects.

MATERIALS AND METHODS

Electronic search of four databases including PubMed/Medline, EMBASE, Web of Science, and Cochrane and hand searching were performed to identify human trials attempting GBR for the reconstruction of alveolar bony defects for at least 10 patients from January 2000 to August 2015. To meet the inclusion criteria, studies had to report preoperative defect dimensions in addition to outcomes of bone formation and/or resorption.

RESULTS

Twenty-five human clinical trials were included of which 17 used conventional technique that is the use of space maintaining membrane with bone grafting particles (GBR I). Application of block bone graft with overlying membrane and particulate fillers was reported in seven studies (GBR II), and utilizing cortical bone block tented over a defect preserving particulate fillers was reported by one study (GBR III). A wide range of initial defects' sizes and treatment results were reported.

CONCLUSIONS

This review introduces a therapeutically oriented classification system of GBR for treating alveolar bone defects. High heterogeneity among studies hindered drawing definite conclusions in regard to superiority of one to the other GBR technique.

Patients' perspectives on dental implant and bone graft surgery: questionnaire-based interview survey

PURPOSE

To assess up-to-date expectations and preferences of patients seeking dental implants.

MATERIAL AND METHODS

One hundred and fifty consecutive patients (66 male and 84 female interviewees) were asked to rank their concerns regarding implant therapy and answer a questionnaire on implant and bone graft surgery, cost and time considerations and second-opinion behaviour.

RESULTS

Treatment predictability and avoidance of removable dentures were ranked high priority (compared with time and cost efficiency or avoidance of bone grafts). Patients' estimation of the 10-year implant success rate was 84%, and 59% of patients expected implants to last for a lifetime. Total treatment time was estimated to be 4 months on average, and only 12% would tolerate increased risk of implant failure for the sake of shortening treatment duration. 61% of interviewees accepted autologous bone grafts (the majority favouring the retromolar area), while only 23% were willing to undergo bone harvesting from the hip. 43% opted for bone substitute material to avoid donor site morbidity. 67% would accept the additional costs associated with computed tomography, software-based treatment planning and guided implant placement to avoid bone graft surgery. Motivation for second-opinion seeking was high (46-62%), especially in young and male patients.

CONCLUSION

Patient expectations on implant success and predictability are high compared with their reluctance towards treatment costs and duration. Acceptance of treatment morbidity is high among patients reporting low denture satisfaction; however, minimally invasive treatment alternatives are generally preferred.

Guided bone regeneration in implant dentistry: Basic principle, progress over 35 years, and recent research activities

Bone augmentation procedures are frequent today in implant patients, since an implant should be circumferentially anchored in bone at completion of bone healing to have a good long-term stability. The best documented surgical technique to achieve this goal is guided bone regeneration (GBR) utilizing barrier membranes in combination with bone fillers. This clinical review paper reflects 35 years of development and progress with GBR. In the 1990s, GBR was developed by defining the indications for GBR, examining various barrier membranes, bone grafts, and bone substitutes. Complications were identified and reduced by modifications of the surgical technique. Today, the selection criteria for various surgical approaches are much better understood, in particular, in post-extraction implant placement. In the majority of patients, biodegradable collagen membranes are used, mainly for horizontal bone augmentation, whereas bioinert PTFE membranes are preferred for vertical ridge augmentation. The leading surgeons are using a composite graft with autogenous bone chips to accelerate bone formation, in combination with a low-substitution bone filer to better maintain the augmented bone volume over time. In addition, major efforts have been made since the millenium change to reduce surgical trauma and patient morbidity as much as possible. At the end, some open questions related to GBR are discussed.

Additive Manufacturing for Guided Bone Regeneration: A Perspective for Alveolar Ridge Augmentation

Three-dimensional (3D) printing has become an important tool in the field of tissue engineering and its further development will lead to completely new clinical possibilities. The ability to create tissue scaffolds with controllable characteristics, such as internal architecture, porosity, and interconnectivity make it highly desirable in comparison to conventional techniques, which lack a defined structure and repeatability between scaffolds. Furthermore, 3D printing allows for the production of scaffolds with patient-specific dimensions using computer-aided design. The availability of commercially available 3D printed permanent implants is on the rise; however, there are yet to be any commercially available biodegradable/bioresorbable devices. This review will compare the main 3D printing techniques of: stereolithography; selective laser sintering; powder bed inkjet printing and extrusion printing; for the fabrication of biodegradable/bioresorbable bone tissue scaffolds; and, discuss their potential for dental applications, specifically augmentation of the alveolar ridge.

Surgical treatment of peri-implantitis with or without a deproteinized bovine bone mineral and a native bilayer collagen membrane: A randomized clinical trial

AIM

To assess whether the use of deproteinized bovine bone mineral (DBBM) and native bilayer collagen membrane (NBCM) improved healing of peri-implantitis-related bone defects at 12 months.

MATERIALS AND METHODS

In a multi-centre, randomized clinical trial, 32 individuals received surgical debridement (control group [CG]), and 34 received adjunct use of DBBM and NBCM (test group [TG]). Radiographic defect fill (RDF), probing pocket depth (PPD), bleeding on probing (BOP), suppuration (SUP), recession (REC), cytokines (IL-1β, IL-1RA, IL-6, IL-8, IL-12, IP10, PDGF-BB, TNF-α, VEGF), and patient-reported outcomes (PROs) were evaluated at 3, 6, 9, and 12 months.

RESULTS

RDF at the deepest site amounted 2.7 ± 1.3 mm in TG and 1.4 ± 1.2 mm in CG (p <.0001). PPD was reduced by 1.9 mm in TG and 2.3 mm in CG (p = .5783). There were no significant differences between groups regarding reductions of BOP, SUP, REC, cytokines levels, or oral health impact profile (OHIP)-14 scores at 12 months. Successful treatment (RDF ≥ 1.0 mm, PPD ≤5 mm, ≤1/4 site with BOP grade 1, no SUP) was identified in 32% in TG and 21% in CG.

CONCLUSIONS

DBBM and NBCM resulted in significantly more RDF than debridement alone. No difference was found in any clinical parameters or PROs between the groups. ClinicalTrials.gov Identifier: NCT02375750.

An Accuracy Study of Computer-Planned Implant Placement in the Augmented Maxilla Using Mucosa-Supported Surgical Templates

PURPOSE

The purpose of this study was to determine the clinically relevant accuracy of implant placement in the augmented maxilla using computer planning and a mucosa-supported surgical template.

MATERIALS AND METHODS

Twenty-five consecutive edentulous patients with an extreme maxillar alveolar ridge resorption were treated with a bone augmentation procedure. In a second stage, six Brånemark MkIII Groovy (Nobel Biocare®, Zürich, Switzerland) implants were installed. Preoperatively, a cone beam computer tomography (CBCT) scan was acquired, followed by virtual implant planning and flapless implant placement using a surgical template. A postoperative CBCT scan was acquired and registered to the preoperative scan. The Implant Position Orthogonal Projection validation method was applied to measure implant deviations in both the buccolingual and mesio-distal plane. The influence of fixation pins and the position on the dental arch were investigated with regard to implant deviations, and rotations and translations of the surgical template.

RESULTS

One hundred fifty implants were installed. In mesio-distal direction, a mean implant deviation of 1.50 mm was scored at the implant tip, 1.27 mm at the shoulder, -0.60 mm in depth, as well as a mean deviation of angulation of 2.50°. In buccolingual direction, a mean implant deviation of 0.99 mm was found at the implant tip, 0.76 mm at the implant shoulder, -0.57 mm in depth, and a deviation of angulation of 2.48°. Of all implants, 53% was placed too superficial compared with the planning. The use of fixation pins and implant deviations in both buccal and mesial directions as also for rotations and translation of the surgical template showed statistically significant differences.

CONCLUSIONS

Computer-aided implant planning showed to be a clinically relevant tool. However, this study emphasizes that the surgeon should take into account that deviations are larger compared with implant placement without augmentation procedure. Deviations are mainly caused by angulations and translations of the surgical template.

The use of platelet-rich fibrin in combination with biphasic calcium phosphate in the treatment of bone defects: a histologic and histomorphometric study

Background

Platelet-rich fibrin (PRF) is a leukocyte and platelet concentrate containing many growth factors. Its potential for hard tissue augmentation as a sole grafting material or in combination with other grafting materials has been investigated in many studies.

Objective

The aim of this histologic study was to evaluate the efficacy of PRF mixed with biphasic calcium phosphate (BCP) on bone regeneration in surgically created bone defects.

Methods

Defects 5 mm in diameter were created in both tibias of 6 sheep. The defects were left empty or grafted with BCP, PRF, or BCP+PRF. Animals were killed at 10, 20, and 40 days. The specimens underwent histologic and histomorphometric analysis.

Results

None of the groups displayed any signs of necrosis. Inflammation was observed in all groups at 10 days; 2 specimens of PRF+BCP and all empty defects showed inflammatory cell infiltration at 20 days. During the 40-day evaluation period, the PRF+BCP group showed the highest ratios of new bone. The other 3 groups showed statistically similar results. In the BCP and PRF+BCP groups, the residual graft ratios were decreased at consecutive time intervals. The difference between the 2 groups was not statistically significant during follow-up.

Conclusions

The current study revealed a histomorphometric increase in bone formation with the addition of PRF to BCP in surgically created defects in sheep tibia.

Bioresorbable zinc hydroxyapatite guided bone regeneration membrane for bone regeneration

OBJECTIVES

The aim of this study was to investigate the bone regenerative properties of a heat treated cross-linked GBR membrane with zinc hydroxyapatite powders in the rat calvarial defect model over a 6-week period.

MATERIAL AND METHODS

In vitro physio-chemical characterization involved X-ray diffraction analysis, surface topology by scanning electron microscopy, and zinc release studies in physiological buffers. Bilateral rat calvarial defects were used to compare the Zn-HAp membranes against the commercially available collagen membranes and the unfilled defect group through radiological and histological evaluation.

RESULTS

The synthesized Zn-MEM (100 μm thick) showed no zinc ions released in the phosphate buffer solution (PBS) buffer, but zinc was observed under acidic conditions. At 6 weeks, both the micro-CT and histological analyses revealed that the Zn-MEM group yielded significantly greater bone formation with 80 ± 2% of bone filled, as compared with 60 ± 5% in the collagen membrane and 40 ± 2% in the unfilled control group.

CONCLUSION

This study demonstrated the use of heat treatment as an alternative method to cross-linking the Zn-MEM to be applied as a GBR membrane. Its synthesis and production are relatively simple to fabricate, and the membrane had rough surface features on one side, which might be beneficial for cellular activities. In a rat calvarial defect model, it was shown that new bone formation was accelerated in comparison with the collagen membrane and the unfilled defect groups. These results would suggest that Zn-MEM has the potential for further development in dental applications.

Esthetic evaluation of single-tooth implants in the anterior maxilla following autologous bone augmentation

OBJECTIVES

Autologous bone augmentation to rebuild compromised alveolar ridge contour prior to implant placement allows for favorable three-dimensional implant positioning to achieve optimum implant esthetics. The aim of the present study was to evaluate peri-implant soft tissue conditions around single-tooth implants following bone grafts in the esthetic zone of the maxilla.

MATERIALS AND METHODS

Sixty patients underwent autologous bone augmentation of deficient maxillary sites prior to placement of 85 implants in the esthetic zone. In case of multiple implants per patient, one implant was randomly selected. Objective evaluation of 60 single-tooth implants was performed using the Pink-Esthetic-Score (PES) and Papilla Index (PI) and supplemented by subjective patient evaluation, as well as clinical and radiologic examination.

RESULTS

Objective ratings of implant esthetics were satisfactory (median PES: 11, median PI: 2) and significantly correlated with high patient satisfaction (mean VAS score: 80%). Both esthetic indices demonstrated respectable levels of inter- as well as intra-observer agreement. Poor implant esthetics (low PES and PI ratings) were significantly associated with increased anatomic crown height, while no influence of horizontal implant-tooth distance could be found.

CONCLUSIONS

The present investigation indicates that favorable esthetic results may be achieved in the augmented anterior maxilla. However, bony reconstruction of compromised alveolar ridges does not guarantee optimum implant esthetics.

Risk factors in bone augmentation procedures

Bone augmentation is an extremely common procedure in implant dentistry today because of significant advancements with reactive biomaterials, a better understanding of the mechanism of action that is found with growth factors contained in platelets, and improvements in surgical techniques. The expectation is for the surgeon to place the dental implant in the position that best serves the requirements of the prosthetic restorations. With the increasing demands that patients have for ideal prosthetic results, surgeons are expected to predictably augment both hard and soft tissues to provide the anticipated esthetic and functional outcomes. Bone grafting can be performed before, during, and after the implant placement; however, these augmentation procedures come with increased cost, the risk of complications such as infection or failure, and lengthening of the total treatment time. In addition, a plethora of grafting materials are available commercially, where they are often inadequately studied, or there is minimal information regarding their predictability or long-term success, or ability to support dental implants. It is clear that although the surgical field has seen major progress since early implant surgical techniques in the 1980s, major challenges still exist with hard tissue augmentation procedures. This review will discuss these challenges that are increased and often specific to bone graft healing, and which are becoming more common as implant site development often requires bone augmentation to improve volume or contour deficiencies. The risk factors that patients may present with that will affect outcomes with bone augmentation procedures are identified, and recommendations for the prevention of complications or managing complications once they have occurred are provided.

Clinical study of octacalcium phosphate and collagen composite in oral and maxillofacial surgery

Octacalcium phosphate and its collagen composite have been recognized as bone substitute materials possessing osteoconductivity and biodegradation properties. We evaluated the effectiveness of octacalcium phosphate and its collagen composite used for bone augmentation in major oral and maxillofacial surgeries in a clinical trial. Octacalcium phosphate and its collagen composite were used in cases of sinus floor elevation in 1- and 2-stage, socket preservation, cyst, and alveolar cleft procedures. A total of 60 patients were evaluated for effectiveness after the implantation of octacalcium phosphate and its collagen composite. Although sinus floor elevation in 1-stage, cyst, and alveolar cleft cases met the criteria for the judgment of success, sinus floor elevation in 2-stage and socket preservation groups did not meet the criteria in the initial evaluation. However, an additional evaluation for reconfirmation revealed the effectiveness of octacalcium phosphate and its collagen composite in those groups, and all evaluation results ultimately indicated the success of this clinical trial. Therefore, this clinical trial suggested that application of octacalcium phosphate and its collagen composite for oral and maxillofacial surgery was safe and effective and that octacalcium phosphate and its collagen composite could be a bone substitute candidate instead of autologous bone.

Buccal bone deficiency in fresh extraction sockets: a prospective single cohort study

OBJECTIVE

The purpose of this prospective single cohort study was to evaluate the use of xenograft and collagen membranes in treating full or partial buccal bone defects of fresh extraction sockets in the esthetic zone.

MATERIALS AND METHODS

Thirty-three patients requiring tooth extraction in the anterior maxillary area and showing a complete or partial buccal bone plate deficiency (more than 2 mm) were consecutively enrolled and treated. Corticocancellous porcine bone and platelet-rich fibrin (PRF) with a collagen membrane were used to graft the extraction sockets, and the membranes were left exposed to the oral cavity with a secondary soft tissue healing. The outcome variables were as follows: width of keratinized mucosa, facial soft tissue levels, clinical bone changes (measured with a clinical splint), implant and prosthesis failures, and peri-implant marginal bone changes.

RESULTS

All treated sites allowed the placement of implants; the width of keratinized mucosa at the mid-facial aspect showed an increase of 2.3 mm 5 months after the grafting procedure, and its value was 3.2 ± 0.6 mm at 1-year follow-up. The mean values of the facial soft tissue level indicated an increase over time. The bone level showed an improvement of 0.8 ± 0.1 mm and 0.7 ± 0.1 mm at mesial and distal sites, respectively, when compared to the baseline measurements. Finally, in the palatal area, no bone changes were observed. No implant failed during the entire observation period.

CONCLUSIONS

Findings from this study showed that xenograft and PRF, used for ridge preservation of the extraction sockets with buccal bone plate dehiscence in the esthetic zone, can be considered effective in repairing bone defects before implant placement. The secondary soft tissue healing over the grafted sockets did not compromise bone formation; moreover, the soft tissue level and the width of keratinized gingiva showed a significant improvement over time.

Interaction between Laser Light and Osteoblasts: Photobiomodulation as a Trend in the Management of Socket Bone Preservation-A Review

Simple Summary

Dental implants are becoming an accepted tool, and thousands of implants are placed every year by specialists and general practitioners. However, more than 10% of bone surgeries and related procedures can show healing complications as a consequence of infections, tissue damage, or inadequate blood supply. In particular, a deficient blood supply impacts on the optimal healing process because of altered oxygen delivery to cells in the wound and a decrease in their energy supply. Researchers showed how red and infrared light affects key cellular pathways by interacting with specific photoacceptors located within the cell, particularly in mitochondria. Low-level laser therapy or photobiomodulation (PBM), as the recent medical subject heading defines it, is based on a light–cell interaction, which modifies cell metabolism by increasing oxygen consumption and ATP production through mitochondria. Although not all aspects of this interconnection are completely described, many in vitro and in vivo studies showed the benefit of PBM in wound defect management. For instance, treatment of bone with PBM results in a greater amount of new-formed osteoblasts and matrix, an increase in collagen synthesis, and microvascular reestablishment. In our review, we highlight the osteoblast–light interaction, and the in vivo therapeutic tool of PBM for socket preservation is discussed.

Abstract

Bone defects are the main reason for aesthetic and functional disability, which negatively affect patient’s quality of life. Particularly, after tooth extraction, the bone of the alveolar process resorbs, limiting the optimal prosthetic implant placement. One of the major pathophysiological events in slowly- or non-healing tissues is a blood supply deficiency, followed by a significant decrease in cellular energy amount. The literature shows that photons at the red and infrared wavelengths can interact with specific photoacceptors located within the cell. Through this mechanism, photobiomodulation (PBM) can modify cellular metabolism, by increasing mitochondrial ATP production. Here, we present a review of the literature on the effect of PBM on bone healing, for the management of socket preservation. A search strategy was developed in line with the PRISMA statement. The PubMed and Scholar electronic databases were consulted to search for in vivo studies, with restrictions on the year (<50 years-old), language (English), bone socket preservation, and PBM. Following the search strategy, we identified 269 records, which became 14, after duplicates were removed and titles, abstract and inclusion-, exclusion-criteria were screened. Additional articles identified were 3. Therefore, 17 articles were included in the synthesis. We highlight the osteoblast–light interaction, and the in vivo therapeutic tool of PBM is discussed.

Selected Nanomaterials' Application Enhanced with the Use of Stem Cells in Acceleration of Alveolar Bone Regeneration during Augmentation Process

Regenerative properties are different in every human tissue. Nowadays, with the increasing popularity of dental implants, bone regenerative procedures called augmentations are sometimes crucial in order to perform a successful dental procedure. Tissue engineering allows for controlled growth of alveolar and periodontal tissues, with use of scaffolds, cells, and signalling molecules. By modulating the patient's tissues, it can positively influence poor integration and healing, resulting in repeated implant surgeries. Application of nanomaterials and stem cells in tissue regeneration is a newly developing field, with great potential for maxillofacial bony defects. Nanostructured scaffolds provide a closer structural support with natural bone, while stem cells allow bony tissue regeneration in places when a certain volume of bone is crucial to perform a successful implantation. Several types of selected nanomaterials and stem cells were discussed in this study. Their use has a high impact on the efficacy of the current and future procedures, which are still challenging for medicine. There are many factors that can influence the regenerative process, while its general complexity makes the whole process even harder to control. The aim of this study was to evaluate the effectiveness and advantage of both stem cells and nanomaterials in order to better understand their function in regeneration of bone tissue in oral cavity.

Reconstruction of mandibular vertical defects for dental implants with autogenous bone block grafts using a tunnel approach: clinical study of 50 cases

The objective of this study was to evaluate the outcomes of mandibular vertical defect reconstruction with autologous bone and the use of a sub-periosteal tunnel approach in preparation for dental implant insertion. Forty-three consecutive patients with an atrophic posterior mandible were reconstructed using this method. Two thin laminae of cortical bone, obtained by splitting blocks harvested from the retromolar area, were fixed in a box-like framework containing cancellous and particulate bone. The goal was to achieve an alveolar ridge width of ≥5.5mm and an effective bone height (EBH) of ≥10.5mm for dental implant insertion (≥3.4mm diameter, ≥9.5mm length). Fifty reconstruction procedures were performed. The mean EBH was 7.1±1.3mm pre-treatment and 12.3±1.1mm post-treatment (mean increase 5.2±1.4mm). Complete graft loss was recorded in two cases; the remaining complications were minor. After a mean consolidation period of 3.5 months, 96 dental implants were placed. No failure of osseointegration was observed at follow-up (mean 32.9 months). The average bone height reduction was 0.9mm (graft vertical resorption 17.4%). Reconstruction of posterior mandibular vertical defects using two autogenous cortical bone blocks with particulate bone between them, combined with a tunnelling technique, provided good healing with no wound dehiscence and minimum resorption of the grafted bone, favouring a substantial vertical bone gain.

Autologous Periosteum-Derived Micrografts and PLGA/HA Enhance the Bone Formation in Sinus Lift Augmentation

Sinus lift augmentation is a procedure required for the placement of a dental implant, whose success can be limited by the quantity or quality of available bone. To this purpose, the first aim of the current study was to evaluate the ability of autologous periosteum-derived micrografts and Poly(lactic-co-glycolic acid) (PLGA) supplemented with hydroxyl apatite (HA) to induce bone augmentation in the sinus lift procedure. Secondly, we compared the micrograft's behavior with respect to biomaterial alone, including Bio-Oss® and PLGA/HA, commercially named Alos. Sinus lift procedure was performed on 24 patients who required dental implants and who, according to the study design and procedure performed, were divided into three groups: group A (Alos + periosteum-derived micrografts); group B (Alos alone); and group C (Bio-Oss® alone). Briefly, in group A, a small piece of periosteum was collected from each patient and mechanically disaggregated by Rigenera® protocol using the Rigeneracons medical device. This protocol allowed for the obtainment of autologous micrografts, which in turn were used to soak the Alos scaffold. At 6 months after the sinus lift procedure and before the installation of dental implants, histological and radiographic evaluations in all three groups were performed. In group A, where sinus lift augmentation was performed using periosteum-derived micrografts and Alos, the bone regeneration was much faster than in the control groups where it was performed with Alos or Bio-Oss® alone (groups B and C, respectively). In addition, the radiographic evaluation in the patients of group A showed a radio-opacity after 4 months, while after 6 months, the prosthetic rehabilitation was improved and was maintained after 2 years post-surgery. In summary, we report on the efficacy of periosteum-derived micrografts and Alos to augment sinus lift in patients requiring dental implants. This efficacy is supported by an increased percentage of vital mineralized tisssue in the group treated with both periosteum-derived micrografts and Alos, with respect to the control group of Alos or Bio-Oss® alone, as confirmed by histological analysis and radiographic evaluations at 6 months from treatment.

Morbidity of anterior iliac crest and calvarial bone donor graft sites: a 1-year randomized controlled trial

Autogenous bone graft harvesting is still commonly considered the gold standard for the reconstruction of a severely resorbed maxillary alveolar ridge; however, the preferred donor site remains a subject of debate. This study compared the morbidity of calvarial and iliac crest donor sites after harvesting. Twenty edentulous patients with an insufficient volume of maxillary bone for reliable implant placement were assigned randomly to either calvarial (n=10) or anterior iliac crest (n=10) bone harvesting groups. All patients underwent a maxillary sinus floor elevation procedure combined with widening of the alveolar process using buccal bone blocks. Donor site morbidity was assessed before, during, and at 1year after the surgery through patient questionnaires, physical examination, and medical records. No perioperative complications occurred. The anterior iliac crest group reported minor postoperative pain after harvesting. The scars after calvaria harvesting were significantly longer (P=0.003), but this was not bothersome for the group of patients. Long-term pain was negligible and satisfaction was high in both groups. Both the calvaria and anterior iliac crest are associated with low long-term donor site morbidity and high patient satisfaction. Thus, patient-centred decision-making is appropriate when selecting the preferred harvesting method for that patient.