Outcomes of Alveolar Ridge Preservation With Recombinant Human Bone Morphogenetic Protein-2: A Systematic Review

Reducing Healing Period with DDM/rhBMP-2 Grafting for Early Loading in Dental Implant Surgery

BACKGROUND

Traditionally, dental implants require a healing period of 4 to 9 months for osseointegration, with longer recovery times considered when bone grafting is needed. This retrospective study evaluates the clinical efficacy of demineralized dentin matrix (DDM) combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) during dental implant placement to expedite the osseointegration period for early loading.

METHODS

Thirty patients (17 male, 13 female; mean age 55.0 ± 8.8 years) requiring bone grafts due to implant fixture exposure (more than four threads; ≥ 3.2 mm) were included, with a total of 96 implants placed. Implants were inserted using a two-stage protocol with DDM/rhBMP-2 grafts. Early loading was initiated at two months postoperatively in the mandible and three months in the maxilla. Clinical outcomes evaluated included primary and secondary stability (implant stability quotient values), healing period, bone width, and marginal bone level assessed via cone-beam computed tomography.

RESULTS

All implants successfully supported final prosthetics with a torque of 50Ncm, without any osseointegration failures. The average healing period was 69.6 days in the mandible and 90.5 days in the maxilla, with significantly higher secondary stability in the mandible (80.7 ± 6.7) compared to the maxilla (73.0 ± 9.2, p < 0.001). Histological analysis confirmed new bone formation and vascularization.

CONCLUSION

DDM/rhBMP-2 grafting appears to significantly reduce the healing period, enabling early loading with stable and favorable clinical outcomes.

A systematic review and meta-analysis on the use of regenerative graft materials for socket preservation in randomized clinical trials

OBJECTIVE

To evaluate if regenerative materials with/without scaffold deployed in dental socket preservation led to reduced radiographic height and width bone resorption.

STUDY DESIGN

English-written human studies from January 2010 to December 2023 were selected from PubMed, EMBASE, MEDLINE, Cochrane CENTRAL, Google Scholar and manually searched journals. Six meta-analyses were conducted, addressing treatments with all blood-derived growth factor preparations as well as L-platelet-rich fibrin (L-PRF) separately, and recombinant human BMP-2 (rhBMP-2). An unpaired t-test on L-PRF and rhBMP-2 determined the clinically best preservation treatment. Cochrane risk of bias in all studies was analyzed.

RESULTS

Twenty-nine articles (1068 participants) were included. Meta-analyses on blood-derived preparations demonstrated nonsignificant alveolar width, but significant (p = .001) height preservation. L-PRF vs. natural healing demonstrated nonsignificant changes in both dimensions. RhBMP-2 caused highly significant reduced horizontal (p = .01) and vertical (p < .0008) bone resorptions. When comparing mean resorption rates, significant benefits of rhBMP-2 over L-PRF were observed for width but not height preservation (p < .0001 and p = .057, respectively). Six studies recorded low, 8 moderate, and 15 high net risks.

CONCLUSIONS

Regenerative materials appear beneficial for radiographic bone width and height preservation after tooth extraction. Although rhBMP-2 performed better in alveolar width preservation, L-PRF can be an autologous and cost-effective alternative.

Effects of Simvastatin-Loaded Nanomicelles on the Early Preservation of Tooth Extraction Sites

Object

The present study intended to evaluate the effect of simvastatin-loaded nanomicelles (SVNs) on promoting new bone formation and reducing alveolar ridge resorption at the tooth extraction sites at the early healing of the extraction sockets.

Methods

SVNs were synthesized using a dialysis method. The rabbit tooth extraction model was established, SVNs and simvastatin (SV) were loaded on gelatin sponge and inserted into the extraction socket. CBCT scans were performed at 0, 2, and 4 weeks postoperatively to evaluate bone formation and alveolar ridge absorption in the extraction sockets. And all the animals were sacrificed and the mandibles were harvested. And HE staining and Masson staining were used for histological evaluation of the bone formation in the extraction sockets.

Results

Radiographic evaluation showed that compared with the blank control group, at 2 and 4 weeks after extraction, SVNs increased the new bone density in the extraction sockets by 75.7% and 96.5%, and reduced the absorption rate of alveolar ridge length at the extraction sites by 60.8% and 49.1%, respectively. Histological evaluation showed that SVNs significantly improved the maturation of new bone tissue in the extraction sockets.

Conclusion

SVNs can significantly accelerate healing and effectively reduce the absorption of alveolar ridge at the extraction sites in the early stage of tooth extraction socket healing.

Sinus floor augmentation using mineralized freeze-dried bone allograft combined with recombinant human bone morphogenetic protein-2 (rhBMP-2): A long-term retrospective study

Background/purpose

The combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) with a carrier material has not been extensively studied. This study aimed to evaluate the clinical, radiological, and histomorphometric outcomes of sinus floor augmentation using a 3:7 mixture of cancellous and cortical freeze-dried bone allografts (mixed AG) combined with rhBMP-2.

Materials and methods

Mixed AG was used for sinus floor augmentation in a total of 21 patients with a residual alveolar bone height <5 mm. Among the total 47 sites, augmentation with and without rhBMP-2 was performed in 26 and 21 sites, respectively. Radiographic parameters were assessed using cone-beam computed tomography. After a six-month healing period, core biopsies were harvested for histomorphometric analysis.

Results

The bone gain after healing was 13.36 ± 3.9 mm and 12.07 ± 3.8 mm in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively. The survival rate of implants in both groups was 100% during the follow-up period. The proportion of newly formed bone was 24.6 ± 10.2% and 39.7 ± 18.3% in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively (P < 0.05). Moreover, the percentage of residual graft material was 21.0 ± 12.2% and 9.6 ± 10.0% in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively (P < 0.05).

Conclusion

Mixed AG combined with rhBMP-2 could be a suitable material for sinus floor augmentation. This combination may reduce the treatment time and improve the predictability of implant placement.

Carrier systems for bone morphogenetic proteins: An overview of biomaterials used for dentoalveolar and maxillofacial bone regeneration

Different types of biomaterials have been used to fabricate carriers to deliver bone morphogenetic proteins (BMPs) in both dentoalveolar and maxillofacial bone regeneration procedures. Despite that absorbable collagen sponge (ACS) is considered the gold standard for BMP delivery, there is still some concerns regarding its use mainly due to its poor mechanical properties. To overcome this, novel systems are being developed, however, due to the wide variety of biomaterial combination, the heterogeneous assessment of newly formed tissue, and the intended clinical applications, there is still no consensus regarding which is more efficient in a particular clinical scenario. The combination of two or more biomaterials in different topological configurations has allowed specific controlled-release patterns for BMPs, improving their biological and mechanical properties compared with classical single-material carriers. However, more basic research is needed. Since the BMPs can be used in multiple clinical scenarios having different biological and mechanical needs, novel carriers should be developed in a context-specific manner. Thus, the purpose of this review is to gather current knowledge about biomaterials used to fabricate delivery systems for BMPs in both dentoalveolar and maxillofacial contexts. Aspects related with the biological, physical and mechanical characteristics of each biomaterial are also presented and discussed.

•

Strategies for bone formation and regeneration are a major concern in dentistry.

•

Topical delivery of bone morphogenetic proteins (BMPs) allows rapid bone formation.

•

BMPs requires proper carrier system to allow controlled and sustained release.

•

Carrier should also fulfill mechanical requirements of bone defect sites.

•

By using complex composites, it would be possible to develop new carriers for BMPs.

Characterizations of alveolar repair after mandibular second molar extraction: an experimental study in rats

BACKGROUND

Characterizations of rat mandibular second molar extraction socket with significantly different buccal and lingual alveolar ridge width remain unclear.

OBJECTIVE

To observe alterations in the alveolar ridge after extraction of mandibular second molars, and to examine processes of alveolar socket healing in an experimental model of alveolar ridge absorption and preservation.

METHODOLOGY

Eighteen Wistar rats were included and divided into six groups regarding healing time in the study. Bilateral mandibular second molars were extracted. The rats with tooth extraction sockets took 0, 1.5, 2, 3, 4 and 8 weeks of healing. Histological observation, tartrate-resistant acidic phosphatase (TRAP) staining, Masson's trichrome staining, immunohistochemical staining and micro-computed tomography (micro-CT) were applied to estimate alterations in the alveolar ridge.

RESULTS

Different buccal and lingual alveolar ridge width led to different height loss. Lingual wall height (LH) decreased significantly two weeks after tooth extraction. Buccal wall height rarely reduced its higher ridge width. From two to eight weeks after extraction, bone volume (BV/TV), density (BMD), and trabecular thickness (Tb.Th) progressively increased in the alveolar socket, which gradually decreased in Tb.Sp and Tb.N. LH showed no significant change during the same period. Osteogenic marker OCN and OPN increased during bone repair from two to eight weeks. The reduced height of the lingual wall of the tooth extraction socket was rarely repaired in the later repair stage. Osteoclast activity led to absorption of the alveolar ridge of the alveolar bone wall within two weeks after operation. We observed positive expression of EMMPRIN and MMP-9 in osteoclasts that participated in the absorption of the spire region.

CONCLUSION

Extraction of rat mandibular second molars may help the study of alveolar ridge absorption and preservation. The EMMPRIN-MMP-9 pathway may be a candidate for further study on attenuating bone resorption after tooth extraction.

Guided bone regeneration with and without rhBMP-2: 17-year results of a randomized controlled clinical trial

Objectives

To assess long‐term outcomes of implants placed in conjunction with guided bone regeneration (GBR) with or without recombinant human bone morphogenetic protein‐2 (rhBMP‐2).

Materials and Methods

Eleven patients with at least two lateral bone defects (split‐mouth design) received a total of 34 implants. The defects were treated with a xenogenic bone substitute with (test) or without (control) rhBMP‐2 and covered with a collagen membrane. Eight patients could be reexamined after at least 17 years. Wilcoxon signed‐rank tests were performed to assess differences between test and control groups.

Results

The implant survival rate was 100% for all test and control sites. Mean marginal bone levels were 2.51 mm (SD ±1.64) (mesial test), 1.83 mm (SD ±0.93) (mesial control) (p = .055), 2.36 mm (SD ±1.70) (distal test), and 2.13 mm (SD ±0.84) (distal control) (p = 1.000). Compared with the mean values at baseline, a mean bone loss of 1.16 mm (SD ±1.60) (test) and 0.70 mm (SD ±1.02) (control) was found. The mean buccal bone gain after 17 years was 5.38 mm (test) and 3.14 mm (control) based on the comparison between the measurements at the cone beam CT after 17 years and the data from the intraoperative measurements at baseline. Further, mean values for (i) bone thickness ranged from 1.36 to 3.09 mm (test) and 1.18 to 3.39 mm (control) and for (ii) mucosal thickness of 1.24 mm (test) and 1.26 mm (control).

Conclusion

Implants placed in conjunction with GBR applying a xenogenic bone substitute and a collagen membrane with and without the addition of rhBMP‐2 demonstrate excellent clinical and radiographic results after at least 17 years.

A Clinical Study on the Effect of Different Ratios of Recombinant Human Bone Morphogenetic Protein-2 Compound to Autogenous Bone on Cervical Interbody Fusion Based on Smart Healthcare

With an increasing elderly population worldwide, the incidence of spine degenerative diseases with neck and shoulder pain as the main symptom is rising obviously, which has now become one of the important and difficult problems in sociomedical science. This study was to explore the effects of different ratios of recombinant human bone morphogenetic protein-2 (rhBMP-2) compound to the autogenous bone on cervical interbody fusion. 90 cervical degeneration patients with the need of surgical treatment admitted to our hospital from January 2019 to January 2020 were selected as the research objects and equally divided into group A, group B, and group C according to the order of admission, with 30 cases in each group and the ratios of rhBMP-2 compound to autogenous bone being 2 : 1, 1 : 1, and 1 : 2 respectively, and standard anterior cervical diskectomy and fusion (ACDF) treatment was performed to all patients to compare their surgery-related indexes, the Japanese Orthopaedic Association (JOA) score, the visual analog scale (VAS) score, the effect of cervical interbody fusion, and the postoperative complication rate (CR). Compared with group A and group C, group B achieved the significantly better surgery-related indexes (P < 0.05), significantly higher postoperative JOA scores (P < 0.05), significantly lower postoperative neck and upper limb VAS scores (P < 0.05), significantly better effect of cervical interbody fusion (P < 0.05), and significantly lower postoperative CR (P < 0.05). 1 : 1 is the best ratio of rhBMP-2 compound to the autogenous bone, for it can optimize patients' perioperative indexes, reduce the postoperative pain, lower the possibility of complications, and improve the effect of cervical interbody fusion, which should be promoted and applied in practice.

Alveolar ridge preservation with fibroblast growth factor-2 modified acellular dermal matrix membrane and a bovine-derived xenograft: An experimental in vivo study

OBJECTIVE

To investigate the effect of a bone substitute material combined with fibroblast growth factor-2 (FGF-2) loaded barrier membrane on the preservation of alveolar ridge after tooth extraction.

MATERIAL AND METHODS

Four dogs were included. Six extraction sockets of each animal received the 3 treatments and were randomly divided into three groups. Group A: negative control; Group B: bovine xenografts + membrane; and Group C: bovine xenografts + FGF-2-loaded membrane. CBCT and histological analysis were performed to evaluate changes in the width and height of alveolar ridges and extraction socket bone healing 8 weeks post-extraction.

RESULTS

CBCT showed that the alveolar bone in Group A was significantly thinner than that in Group B and Group C at 1 and 3 mm apically from the alveolar crest. The alveolar width at 1 mm in Group C (60.99 ± 15.36%) was significantly thicker than that in Group B (39.75 ± 30.18%). Histomorphmetrical measurements showed that the buccal alveolar width at 1 mm was significantly thicker in Groups B and C than in Group A. Additionally, buccal bone height and lingual bone width at 1 mm in Group C (87.06 ± 10.34%, 89.09 ± 10.56%) were significantly greater than in Group A (53.48 ± 23.94%, 82.72 ± 12.59%).

CONCLUSION

The present findings indicate that application of bovine bone combined with barrier membrane with or without FGF-2 over tooth sockets can effectively reduce ridge absorption, especially in terms of ridge width and FGF-2 modified membrane seems to improve the outcomes obtained with membrane alone.

Prognosis of single tooth implants following alveolar ridge preservation with two recombinant human bone morphogenetic protein-2 delivery systems

Background

We previously reported similar efficacies of alveolar ridge preservation (ARP) on single extraction socket with two different E. coli derived recombinant human bone morphogenetic protein-2 (rhBMP-2) delivery systems (Cowell BMP, Cowell medi Co, Busan, Korea; β-tricalcium phosphate and hydroxyapatite particle & O-BMP, Osstem Implant Co, Busan, Korea; absorbable collagen sponge). After the trial, we completed implant therapy and observed over an average of 3 years. This follow-up study was performed retrospectively to compare result of implant treatment at the preserved alveolar ridge site.

Methods

Patients who underwent extraction of single tooth and received ARP with one of two rhBMP-2 delivery systems from October 2015 to October 2016 were enrolled. Twenty-eight patients (Group 1: Cowell BMP 14; Group 2: O-BMP 14) who underwent implant therapy and prosthetic treatment were included in study. Stability and marginal bone loss (MBL) of each implant were collected from medical charts and radiographs, and analyzed. The survival and success rates of implants were calculated.

Results

The primary implant stability represented by implant stability quotient (ISQ) for Groups 1 and 2 was 69.71 and 72.86, respectively. The secondary implant stability for Groups 1 and 2 was 78.86 and 81.64, respectively. Primary and secondary stabilities were not statistically different (P = 0.316 and 0.185, respectively). MBL at the latest follow-up was 0.014 mm in Group 1 over 33.76 ± 14.31 months and 0.021 mm in Group 2 over 40.20 ± 9.64 months, with no significant difference (P = 0.670). In addition, the success rate of implants was 100% (14/14) in Group 1 and 92.9% (13/14) in Group 2, with survival rate of 100% (14/14) in Group 1 and 92.9% (13/14) in Group 2.

Conclusions

We confirmed good prognosis in both groups as a result of implant therapy after ARP with each of two rhBMP-2 carriers.

Preliminary evaluation of BMP-2-derived peptide in repairing a peri-implant critical size defect: A canine model

BACKGROUND/PURPOSE

A synthetic bone morphogenetic protein (BMP)-2-derived peptide has been discovered to promote bone regeneration. The present study investigated the potential of the BMP-2 peptide combined with hydroxyapatite (HAp)/β-tricalcium phosphate (TCP)/collagen (Col) composite in repairing a peri-implant critical size defect.

METHODS

Twenty-four saddle-type alveolar defects (10 mm mesiodistally and 4 mm apicocoronally) were surgically prepared in edentulous ridges in four male beagle dogs. Following implant placement, the defects with vertically exposed implant fixtures received (a) HAp/TCP/Col composite, (b) HAp/TCP/Col + 4 mg/mL BMP-2 peptide, (c) HAp/TCP/Col + 20 mg/mL BMP-2 peptide, or (d) HAp/TCP/Col + 0.2 mg/mL recombinant human BMP-2 (rhBMP-2). Bone regeneration and mineralization were assessed using radiography, micro-computed tomography (micro-CT), fluorescence labeling, and histologic analyses after healing for 4 or 8 weeks. Implant stability was measured using resonance frequency analysis.

RESULTS

The 20 mg/mL BMP-2 peptide groups demonstrated a distinguishable advantage in bone regeneration potential over the control groups, as observed on radiographic imaging and histologic examination, although no significant difference was found in implant stability and histomorphometric analysis of mineralization levels. However, the performance of the 20 mg/mL BMP-2 peptide groups were inferior to that of the 0.2 mg/mL rhBMP-2 groups.

CONCLUSION

The BMP-2 peptide may accelerate peri-implant bone regeneration. The BMP-2 peptide at 20 mg/mL still cannot complete bone repair of peri-implant critical size defect. The BMP-2 peptide at 20 mg/mL has similar osteoinductive performance to the rhBMP-2 at 0.02 mg/mL.

Effectiveness of Bone Graft for an Alveolar Defect on Adjacent Second Molar After Impacted Mandibular Third Molar Extraction

PURPOSE

This retrospective study examined distal bone healing on the adjacent second molar between the demineralized bone matrix incorporated with recombinant human bone morphogenetic protein-2 (DBM/rhBMP-2) and a collagen sponge in the mandibular third molar extraction socket.

MATERIALS AND METHODS

From 2018 to 2020, 26 extraction patients (male, average 21.5 years), who received a graft (each of 13 using DBM/rhBMP-2 and collagen plug, respectively) on the extraction socket without primary closure, were enrolled in this study. The bony defect was measured by computed tomography before and 6 months after the extraction. The difference in the bone healing was analyzed between the DBM/rhBMP-2 and collagen plug groups using a Mann-Whitney U test.

RESULTS

No complications, such as infection and food packing, were encountered. The DBM/rhBMP-2 and collagen plug groups showed a similar distribution of preoperative bony defect (median 5.8 and 5.0 mm, respectively). After 6 months, more bone healing was observed in the DBM/rhBMP-2 group than in the collagen plug group (median 3.85 and 2.37 mm, respectively, P = .029) CONCLUSIONS: A DBM/rhBMP-2 graft after a third molar extraction does significantly alter the bony defect on the distal aspect of the second molar compared with a collagen plug.

Post-extraction dimensional changes: A systematic review and meta-analysis

AIM

To analyse the evidence pertaining to post-extraction dimensional changes in the alveolar ridge after unassisted socket healing.

MATERIALS AND METHODS

The protocol of this PRISMA-compliant systematic review (SRs) was registered in PROSPERO (CRD42020178857). A literature search to identify studies that fulfilled the eligibility criteria was conducted. Data of interest were extracted. Qualitative and random-effects meta-analyses were performed if at least two studies with comparable features and variables reported the same outcome of interest.

RESULTS

Twenty-eight articles were selected, of which 20 could be utilized for the conduction of quantitative analyses by method of assessment (i.e. clinical vs radiographic measurements) and location (i.e. non-molar vs molar sites). Pooled estimates revealed that mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed clinically in non-molar sites was 2.73 mm (95% CI: 2.36-3.11), 1.71 mm (95% CI: 1.30-2.12) and 1.44 mm (95% CI: 0.78-2.10), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in non-molar sites was 2.54 mm (95% CI: 1.97-3.11), 1.65 mm (95% CI: 0.42-2.88) and 0.87 mm (95% CI: 0.36-1.38), respectively. Mean horizontal, vertical mid-facial and mid-lingual ridge reduction assessed radiographically in molar sites was 3.61 mm (95% CI: 3.24-3.98), 1.46 mm (95% CI: 0.73-2.20) and 1.20 mm (95% CI: 0.56-1.83), respectively.

CONCLUSION

A variable amount of alveolar bone resorption occurs after unassisted socket healing depending on tooth type.

Effect of alveolar ridge preservation interventions following tooth extraction: A systematic review and meta-analysis

AIM

The aim of this systematic review was to critically analyse the available evidence on the effect of different modalities of alveolar ridge preservation (ARP) as compared to tooth extraction alone in function of relevant clinical, radiographic and patient-centred outcomes.

MATERIAL AND METHODS

A comprehensive search aimed at identifying pertinent literature for the purpose of this review was conducted by two independent examiners. Only randomized clinical trials (RCTs) that met the eligibility criteria were selected. Relevant data from these RCTs were collated into evidence tables. Endpoints of interest included clinical, radiographic and patient-reported outcome measures (PROMs). Interventions reported in the selected studies were clustered into ARP treatment modalities. All these different ARP modalities were compared to the control therapy (i.e. spontaneous socket healing) in each individual study after a 3- to 6-month healing period. Random-effects meta-analyses were conducted if at least two studies within the same ARP treatment modality reported on the same outcome of interest.

RESULTS

A combined database, grey literature and hand search identified 3,003 records, of which 1,789 were screened after removal of duplicates. Following the application of the eligibility criteria, 25 articles for a total of 22 RCTs were included in the final selection, from which nine different ARP treatment modalities were identified: (a) bovine bone particles (BBP) + socket sealing (SS), (b) construct made of 90% bovine bone granules and 10% porcine collagen (BBG/PC) + SS, (c) cortico-cancellous porcine bone particles (CPBP) + SS, (d) allograft particles (AG) + SS, (e) alloplastic material (AP) with or without SS, (f) autologous blood-derived products (ABDP), (g) cell therapy (CTh), (h) recombinant morphogenic protein-2 (rhBMP-2) and (i) SS alone. Quantitative analyses for different ARP modalities, all of which involved socket grafting with a bone substitute, were feasible for a subset of clinical and radiographic outcomes. The results of a pooled quantitative analysis revealed that ARP via socket grafting (ARP-SG), as compared to tooth extraction alone, prevents horizontal (M = 1.99 mm; 95% CI 1.54-2.44; p < 0.00001), vertical mid-buccal (M = 1.72 mm; 95% CI 0.96-2.48; p < 0.00001) and vertical mid-lingual (M = 1.16 mm; 95% CI 0.81-1.52; p < 0.00001) bone resorption. Whether there is a superior ARP or SS approach could not be determined on the basis of the selected evidence. However, the application of particulate xenogenic or allogenic materials covered with an absorbable collagen membrane or a rapidly absorbable collagen sponge was associated with the most favourable outcomes in terms of horizontal ridge preservation. A specific quantitative analysis showed that sites presenting a buccal bone thickness >1.0 mm exhibited more favourable ridge preservation outcomes (difference between ARP [AG + SS] and control = 3.2 mm), as compared to sites with a thinner buccal wall (difference between ARP [AG + SS] and control = 1.29 mm). The effect of other local and systemic factors could not be assessed as part of the quantitative analyses. PROMs were comparable between the experimental and the control group in two studies involving the use of ABDP. The effect of other ARP modalities on PROMs could not be investigated, as these outcomes were not reported in any other clinical trial included in this study.

CONCLUSION

Alveolar ridge preservation is an effective therapy to attenuate the dimensional reduction of the alveolar ridge that normally takes place after tooth extraction.

Extraction Socket Preservation Using Growth Factors and Stem Cells: a Systematic Review

Objectives

To evaluate the reported literature on the use of stem cells or growth factors for post extraction treatment of the alveolar bone.

Material and Methods

A NCBI PubMed and PubMed Central databases search was conducted between September 2010 and August 2018, to identify animal or clinical studies reporting the clinical, radiographical and/or histological outcomes of socket preservation techniques after applying mesenchymal stem cells or growth factors. Only studies published in English language in the last 10 years were included in the study.

Results

Eleven studies were identified fulfilling the inclusion criteria. They evaluate a total of 386 post extraction sockets. The main tested materials identified in the current review were bone morphogenetic protein-2 - 3 studies and mesenchymal stem cells - 3 studies. Other comparators were bone morphogenetic protein-9, platelet-derived growth factor-BB homodimers and bone marrow. Overall evaluation indicate positive results for all test groups showing differences in final socket width between 0.64 and 1.28 mm favouring the test groups. Histologically, no particular differences are detected between test and control groups. Most of the studies present low risk of bias.

Conclusions

In general, the use of mesenchymal stem cells or bioactive osteogenic molecules favours bone regeneration after tooth extraction, as evaluated clinically, radiographically and histologically. However, specific differences that support particular recommendations are still unclear in light of the current published evidence. Future studies should include the standardization of the mesenchymal stem cells selection and purification as well as dosage and delivery methods of bioactive molecules.

Safety and Efficacy of Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) in Craniofacial Surgery

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is one of the most commonly used osteogenic agents in the craniofacial skeleton. This study reviews the safety and efficacy of rhBMP-2 as applied to craniofacial reconstruction and assesses the level of scientific evidence currently available.

Postulated release profile of recombinant human bone morphogenetic protein-2 (rhBMP-2) from demineralized dentin matrix

Demineralized dentin matrix (DDM) has been used as a recombinant human bone morphogenetic protein-2 (rhBMP-2) carrier in many clinical trials. To optimize the clinical safety and efficacy of rhBMP-2 with DDM, efforts have been made to improve the delivery of rhBMP-2 by 1) lowering the administered dose, 2) localizing the protein, and 3) prolonging its retention time at the action site as well as the bone forming capacity of the carrier itself. The release profile of rhBMP-2 that is associated with endogenous BMP in dentin has been postulated according to the type of incorporation, which is attributed to the loosened interfibrillar space and nanoporous dentinal tubule pores. Physically adsorbed and modified, physically entrapped rhBMP-2 is sequentially released from the DDM surface during the early stage of implantation. As DDM degradation progresses, the loosened interfibrillar space and enlarged dentinal tubules release the entrapped rhBMP-2. Finally, the endogenous BMP in dentin is released with osteoclastic dentin resorption. According to the postulated release profile, DDM can therefore be used in a controlled manner as a sequential delivery scaffold for rhBMP-2, thus sustaining the rhBMP-2 concentration for a prolonged period due to localization. In addition, we attempted to determine how to lower the rhBMP-2 concentration to 0.2 mg/mL, which is lower than the approved 1.5 mg/mL.

A randomized controlled clinical trial evaluating efficacy and adverse events of different types of recombinant human bone morphogenetic protein-2 delivery systems for alveolar ridge preservation

OBJECTIVES

This 12-week clinical trial evaluated efficacy and adverse events for two recombinant human bone morphogenetic protein-2 (rhBMP-2) delivery systems in alveolar ridge preservation.

MATERIALS AND METHODS

Sixty-four patients had a single tooth that required replacement with an implant, surrounded by > 50% alveolar bone height. Two cohorts (n = 32 patients each) were randomized to receive a rhBMP-2-soaked absorbable collagen sponge (test group), or β-tricalcium phosphate and hydroxyapatite particles (control group) immersed in rhBMP-2, at the implant site. Bone height and width changes at 25%, 50%, and 75% of extraction socket level (ESL) were compared. Adverse events were assessed in the same period. In addition to the randomized controlled clinical trial, histological analysis of 21 patients (test group [n = 12], control group [n = 9]) was conducted, 4 months after alveolar ridge preservation. A non-inferiority test was used to analyze changes in alveolar bone height between groups (p = 0.05). A Wilcoxon rank-sum test was used to analyze changes in alveolar bone width and histomorphometric results between groups (p = 0.05).

RESULTS

All patients showed good healing without severe adverse events. The lower limit of the one-sided 97.5% confidence interval in the difference between the two groups was 0.0033 (non-inferiority margin: -0.185); thus, the test group showed non-inferiority to the control group. Wilcoxon rank-sum test analysis did not show statistically significant differences between groups with regard to changes in alveolar bone width and histomorphometric analysis.

CONCLUSIONS

The delivery systems showed similar efficacy for alveolar ridge preservation without severe adverse events.

Biomodification of compromised extraction sockets using hyaluronic acid and rhBMP-2: An experimental study in dogs

BACKGROUND

This experimental study aims to evaluate the effect of hyaluronic acid on healing of infected extraction sockets compared with recombinant human bone morphogenetic protein-2 (rhBMP-2).

METHODS

Both third and fourth mandibular premolars of six beagle dogs were hemisected, and the distal roots were extracted at baseline. Subsequently, combined endodontic-periodontic lesions were induced at the remaining mesial roots. After 4 months, the mesial roots on both sides of the mandible were removed. Four sockets per dog were randomly allocated to four groups: Group 1, Control; Group 2, only absorbable collagen sponge (ACS: carrier); Group 3, 1% hyaluronic acid (HA) gel + ACS; and Group 4, rhBMP-2 + ACS. After 3 months of healing, the dogs were euthanized for microcomputed tomography and histologic analysis.

RESULTS

After the lesion induction period (4 months), communication between the periodontal lesion and endodontic periapical lesion was observed at all remaining mesial roots. Alveolar bone overgrowth was observed in groups 3 and 4, but bone volume density was not significantly different among all groups. At the crestal portion, mineralization, and osteocalcin expression were higher in groups 3 and 4 than in groups 1 and 2.

CONCLUSION

Treatment with HA can promote bone formation and improve the wound healing rate comparable to rhBMP-2 in infected extraction sockets.