Randomized clinical study using xenograft blocks loaded with bone morphogenetic protein‐2 or autogenous bone blocks for ridge augmentation – A three‐dimensional analysis

The Clinical Efficacy and Safety of ErhBMP-2/BioCaP/β-TCP as a Novel Bone Substitute Using the Tooth-Extraction-Socket-Healing Model: A Proof-of-Concept Randomized Controlled Trial

AIM

This first randomized controlled trial in humans aimed to assess the efficacy and safety of low-dosage Escherichia coli-derived recombinant human bone morphogenetic protein 2 (ErhBMP-2)-incorporated biomimetic calcium phosphate coating-functionalized β-TCP (ErhBMP-2/BioCaP/β-TCP) as a novel bone substitute using the tooth-extraction-socket-healing model.

MATERIALS AND METHODS

Forty patients requiring dental implants after single-root tooth extraction were enrolled in this study and randomly assigned into three groups: ErhBMP-2/BioCaP/β-TCP (N = 15), β-TCP (N = 15) and natural healing (N = 10). New bone volume density from histomorphometric analyses was evaluated 6 weeks post-operatively as the primary outcome, and other histomorphometric analyses, alveolar bone and soft-tissue changes were the secondary outcomes. Safety parameters included adverse events, soft-tissue healing, oral health impact profile, serum BMP-2 concentrations and other laboratory tests.

RESULTS

The findings revealed a significant increase in new bone volume density in patients treated with ErhBMP-2/BioCaP/β-TCP compared to those receiving β-TCP alone. The required bone augmentation procedures during implant placement surgery in the ErhBMP-2/BioCaP/β-TCP group were significantly less than in the natural healing group. There were no significant differences in safety parameters among the three groups.

CONCLUSION

This clinical trial primarily proved the safety and efficacy of ErhBMP-2/BioCaP/β-TCP as a promising bone substitute.

Horizontal ridge augmentation in the maxillary aesthetic region using the autogenous circular cortical-lamina anchoring technique: A case series study

AIM

This case series aimed to evaluate the effectiveness of the autologous circular cortical lamina-anchoring (CCA) technique for horizontal bone augmentation in the maxillary aesthetic region.

MATERIALS AND METHODS

A total of 25 patients with 28 implants underwent horizontal bone augmentation using CCA followed by implant placement and crown delivery. The primary outcome measures were alveolar ridge width (ARW) and buccal bone thickness (BBT), whereas the secondary outcome measures included marginal bone loss (MBL), mid-facial mucosal margin loss (MML), clinical assessment of peri-implant and aesthetic parameters, patient-reported outcome measures (PROMs), and implant survival rates.

RESULTS

All 25 patients with 28 implants completed the treatment, no dropouts occurred. After CCA, the mean ARW at 1, 2, and 4 mm below the alveolar crest significantly increased from 2.38 ± 0.48, 2.85 ± 0.51, and 3.21 ± 0.53 mm to 6.80 ± 0.48, 6.99 ± 0.50, and 8.08 ± 0.52 mm, respectively. At the 3-year follow-up, the mean BBT0, BBT2, and BBT4 slightly decreased from 2.51 ± 0.26, 2.63 ± 0.31, and 2.75 ± 0.29 mm to 2.43 ± 0.27, 2.51 ± 0.30, and 2.64 ± 0.28 mm, respectively. Although the overall MBL was <0.15 mm, the results were statistically significant. The mean MML at the 3-year follow-up was 0.02 mm. All implant sites showed acceptable peri-implant and aesthetic outcomes. Incisions healed without complications, and no significant differences in PROMs observed at any time point. The 3-year follow-up showed a 100% implant survival rate.

CONCLUSION

The autologous CCA technique is a useful method for increasing ARW and maintaining BBT in the maxillary aesthetic region.

A Comparison of Guided Bone Regeneration vs. the Shell Technique Using Xenogeneic Bone Blocks in Horizontal Bone Defects: A Randomized Clinical Trial

In cases of severe horizontal atrophy, implant placement requires bone reconstruction procedures. The aim of this randomized controlled trial is to compare the outcomes of bone augmentation with simultaneous implant placement using the shell technique to the outcomes of guided bone regeneration (GBR) in cases of severely horizontal bone atrophy. This study was designed as a monocentric, parallel-group, randomized controlled trial with a six-month follow-up. Among the primary outcomes of this study, peri-implant bone regeneration and peri-implant bone defect closure were selected. Forty-four patients were recruited and equally divided between two groups. In the GRB group, a horizontal regeneration of 2.31 ± 0.23 mm was observed opposed to a horizontal regeneration of 2.36 ± 0.17 mm in the shell group (p = 0.87). A volumetric increase was observed in both groups, with an increase of 0.30 ± 0.12 cm3 in the GBR group and an increase of 0.39 ± 0.09 cm3 in the shell group, highlighting a significant difference between the two groups (p = 0.02). In conclusion, bone augmentation with simultaneous implant placement using the shell technique or guided bone regeneration in horizontal bone atrophy are both predictable therapeutic options.

Ridge preservation using a self-retaining block type bone substitute for extraction sockets with buccal dehiscence defects - A preclinical study

OBJECTIVE

To evaluate the effect of a self-retaining block-type bone substitute (srBB) on the dimensional stability of the horizontal ridge width at the coronal level in a buccal dehiscence model.

MATERIALS AND METHODS

Four box-shaped bone defects with a buccal dehiscence were surgically prepared in the partially edentulous mandible (n = 6). Experimental biomaterials were randomly assigned to each site: (1) Control group: no treatment, (2) particle-type bone substitute (PBS) group, (3) collagenated soft block bone substitute (csBB) group, and (4) self-retaining synthetic block bone (srBB) group. In all grafted groups, a collagen membrane covered the biomaterials. At 16 weeks, clinical, histological, and radiographic analyses were performed.

RESULTS

Three of the six blocks in the srBB group became exposed and fell out during the first week after surgery. Therefore, the remaining three specimens were renamed RsrBB group. The RsrBB group showed an increase horizontal ridge compared to the pristine bone width at 2-4 mm below the CEJ, while the other groups showed resorption (augmented width at 2 mm below: 4.2, 42.4, 36.2, and 110.1% in the control, PBS, csBB, and RsrBB groups, respectively). The mineralized bone area was largest in the RsrBB group (4.74, 3.44, 5.67, and 7.77 mm2 in the control, PBS, csBB, and RsrBB groups, respectively.).

CONCLUSIONS

The srBB group demonstrated the highest volume stability at the coronal level. These findings would potentially suggest that self-retaining block bone substitute might be a good candidate for alveolar ridge preservation.

Twenty-five years of recombinant human growth factors rhPDGF-BB and rhBMP-2 in oral hard and soft tissue regeneration

Contemporary oral tissue engineering strategies involve recombinant human growth factor approaches to stimulate diverse cellular processes including cell differentiation, migration, recruitment, and proliferation at grafted areas. Recombinant human growth factor applications in oral hard and soft tissue regeneration have been progressively researched over the last 25 years. Growth factor-mediated surgical approaches aim to accelerate healing, tissue reconstruction, and patient recovery. Thus, regenerative approaches involving growth factors such as recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and recombinant human bone morphogenetic proteins (rhBMPs) have shown certain advantages over invasive traditional surgical approaches in severe hard and soft tissue defects. Several clinical studies assessed the outcomes of rhBMP-2 in diverse clinical applications for implant site development and bone augmentation. Current evidence regarding the clinical benefits of rhBMP-2 compared to conventional therapies is inconclusive. Nevertheless, it seems that rhBMP-2 can promote faster wound healing processes and enhance de novo bone formation, which may be particularly favorable in patients with compromised bone healing capacity or limited donor sites. rhPDGF-BB has been extensively applied for periodontal regenerative procedures and for the treatment of gingival recessions, showing consistent and positive outcomes. Nevertheless, current evidence regarding its benefits at implant and edentulous sites is limited. The present review explores and depicts the current applications, outcomes, and evidence-based clinical recommendations of rhPDGF-BB and rhBMPs for oral tissue regeneration.

The impact of membrane perforation and L-PRF for vertical ridge augmentation with a xenogeneic block graft: an experimental study in a canine model

OBJECTIVES

This study evaluated clinically and histologically the efficacy of modified perforated collagen membrane (PCM) and/or leukocyte- and platelet-rich fibrin (L-PRF) in combination with xenogeneic block bone graft in the vertical alveolar ridge augmentation.

MATERIALS AND METHODS

Six adult mongrel dogs were enrolled in this randomized blinded study. After defect preparation, xenogeneic screw-fixed block graft was covered by an occlusive collagen membrane in group 1 that represented the control group (Block + CM). In group 2, L-PRF membrane was added first before top coverage by occlusive collagen membrane (Block + L-PRF + CM). Groups 3 (Block + PCM) and 4 (Block + L-PRF + PCM) were identical to the first two groups except that the occlusive collagen membrane was replaced by a perforated one. Following a healing period of 2 months, the dogs were submitted to the surgical reentry phase for clinical and histological evaluation.

RESULTS

Clinically, no significant differences were found among all groups regarding vertical and horizontal ridge dimensions (p = 0.155, 0.492, respectively). Histomorphometric analysis revealed that the percentage of the total bone area and mature bone was significantly higher in group 4 (69.36 ± 2.72, 33.11 ± 5.18) compared to the control group (59.17 ± 4.27, 21.94 ± 2.86) (p = 0. 027, p = 0.029).

CONCLUSION

The use of xenogenic block grafts in combination with a double-layered perforated collagen L-PRF membrane in vertical ridge augmentation appeared to improve the inductive power of this challenging defect type.

CLINICAL RELEVANCE

Size and number of perforations may affect the mechanical and handling properties of the membrane.

Radiographic evaluation of the tenting screw technique in horizontal alveolar bone augmentation: A retrospective study

OBJECTIVES

To radiographically analyze the effects of tenting screw technique (TS) and onlay bone grafts (OG) in horizontal bone augmentation.

MATERIALS AND METHODS

Patients receiving horizontal bone augmentation by TS or OG were selected. The clinical outcomes and cone beam computed tomography (CBCT) data were documented pre-grafting, immediately post-grafting, before and after implantation. The survival rates, clinical complications, alveolar bone width, and volumetric bone augmentation were evaluated and statistically analyzed.

RESULTS

A total of 25 patients and 41 implants were involved in this study, with no grafting failures observed in either the TS group (n = 20) or the onlay group (n = 21). Volumetric bone resorption rate in the TS group (21.34%) was significantly lower than that of the OG group (29.38%). In addition, significant horizontal bone gain was achieved in both groups (TS: 6.15 ± 2.12 mm; OG: 4.86 ± 1.40 mm) during the recovery period, with higher gain in the TS group. No apparent statistical difference in terms of volumetric bone gain was observed between the TS (748.53 mm³ , 607.47 mm³ ) and OG group (811.77 mm³ , 508.49 mm³ ) immediately post-grafting or after the recovery period.

CONCLUSION

Both TS and OG achieved satisfactory bone augmentation effects, yet TS resulted in more bone augmentation and better stability than OG, with a reduced use of autogenous bone. Overall, the tenting screw technique can serve as an effective alternative to autogenous bone grafts.

The current regenerative medicine approaches of craniofacial diseases: A narrative review

Craniofacial deformities (CFDs) develop following oncological resection, trauma, or congenital disorders. Trauma is one of the top five causes of death globally, with rates varying from country to country. They result in a non-healing composite tissue wound as they degenerate in soft or hard tissues. Approximately one-third of oral diseases are caused by gum disease. Due to the complexity of anatomical structures in the region and the variety of tissue-specific requirements, CFD treatments present many challenges. Many treatment methods for CFDs are available today, such as drugs, regenerative medicine (RM), surgery, and tissue engineering. Functional restoration of a tissue or an organ after trauma or other chronic diseases is the focus of this emerging field of science. The materials and methodologies used in craniofacial reconstruction have significantly improved in the last few years. A facial fracture requires bone preservation as much as possible, so tiny fragments are removed initially. It is possible to replace bone marrow stem cells with oral stem cells for CFDs due to their excellent potential for bone formation. This review article discusses regenerative approaches for different types of craniofacial diseases.

Clinical and patient-reported outcomes of tissue engineering strategies for periodontal and peri-implant reconstruction

Scientific advancements in biomaterials, cellular therapies, and growth factors have brought new therapeutic options for periodontal and peri-implant reconstructive procedures. These tissue engineering strategies involve the enrichment of scaffolds with living cells or signaling molecules and aim at mimicking the cascades of wound healing events and the clinical outcomes of conventional autogenous grafts, without the need for donor tissue. Several tissue engineering strategies have been explored over the years for a variety of clinical scenarios, including periodontal regeneration, treatment of gingival recessions/mucogingival conditions, alveolar ridge preservation, bone augmentation procedures, sinus floor elevation, and peri-implant bone regeneration therapies. The goal of this article was to review the tissue engineering strategies that have been performed for periodontal and peri-implant reconstruction and implant site development, and to evaluate their safety, invasiveness, efficacy, and patient-reported outcomes. A detailed systematic search was conducted to identify eligible randomized controlled trials reporting the outcomes of tissue engineering strategies utilized for the aforementioned indications. A total of 128 trials were ultimately included in this review for a detailed qualitative analysis. Commonly performed tissue engineering strategies involved scaffolds enriched with mesenchymal or somatic cells (cell-based tissue engineering strategies), or more often scaffolds loaded with signaling molecules/growth factors (signaling molecule-based tissue engineering strategies). These approaches were found to be safe when utilized for periodontal and peri-implant reconstruction therapies and implant site development. Tissue engineering strategies demonstrated either similar or superior clinical outcomes than conventional approaches for the treatment of infrabony and furcation defects, alveolar ridge preservation, and sinus floor augmentation. Tissue engineering strategies can promote higher root coverage, keratinized tissue width, and gingival thickness gain than scaffolds alone can, and they can often obtain similar mean root coverage compared with autogenous grafts. There is some evidence suggesting that tissue engineering strategies can have a positive effect on patient morbidity, their preference, esthetics, and quality of life when utilized for the treatment of mucogingival deformities. Similarly, tissue engineering strategies can reduce the invasiveness and complications of autogenous graft-based staged bone augmentation. More studies incorporating patient-reported outcomes are needed to understand the cost-benefits of tissue engineering strategies compared with traditional treatments.

Preclinical Evaluation of BMP-9-Treated Human Bone-like Substitutes for Alveolar Ridge Preservation following Tooth Extraction

The success of dental implant treatment after tooth extraction is generally maximized by preserving the alveolar ridge using cell-free biomaterials. However, these treatments can be associated with inflammatory reactions, leading to additional bone volume loss hampering dental implant positioning. Our group developed a self-assembled bone-like substitute constituted of osteogenically induced human adipose-derived stromal/stem cells (hASCs). We hypothesized that a bone morphogenetic protein (BMP) supplementation could improve the in vitro osteogenic potential of the bone-like substitute, which would subsequently translate into enhanced alveolar bone healing after tooth extraction. ASCs displayed a better osteogenic response to BMP-9 than to BMP-2 in monolayer cell culture, as shown by higher transcript levels of the osteogenic markers RUNX2, osterix (OSX/SP7), and alkaline phosphatase after three and six days of treatment. Interestingly, BMP-9 treatment significantly increased OSX transcripts and alkaline phosphatase activity, as well as pro-angiogenic angiopoietin-1 gene expression, in engineered bone-like substitutes after 21 days of culture. Alveolar bone healing was investigated after molar extraction in nude rats. Microcomputed tomography and histological evaluations revealed similar, or even superior, global alveolar bone preservation when defects were filled with BMP-9-treated bone-like substitutes for ten weeks compared to a clinical-grade biomaterial, with adequate gingival re-epithelialization in the absence of resorption.

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.

Polymeric Scaffolds for Dental, Oral, and Craniofacial Regenerative Medicine

Dental, oral, and craniofacial (DOC) regenerative medicine aims to repair or regenerate DOC tissues including teeth, dental pulp, periodontal tissues, salivary gland, temporomandibular joint (TMJ), hard (bone, cartilage), and soft (muscle, nerve, skin) tissues of the craniofacial complex. Polymeric materials have a broad range of applications in biomedical engineering and regenerative medicine functioning as tissue engineering scaffolds, carriers for cell-based therapies, and biomedical devices for delivery of drugs and biologics. The focus of this review is to discuss the properties and clinical indications of polymeric scaffold materials and extracellular matrix technologies for DOC regenerative medicine. More specifically, this review outlines the key properties, advantages and drawbacks of natural polymers including alginate, cellulose, chitosan, silk, collagen, gelatin, fibrin, laminin, decellularized extracellular matrix, and hyaluronic acid, as well as synthetic polymers including polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), poly (ethylene glycol) (PEG), and Zwitterionic polymers. This review highlights key clinical applications of polymeric scaffolding materials to repair and/or regenerate various DOC tissues. Particularly, polymeric materials used in clinical procedures are discussed including alveolar ridge preservation, vertical and horizontal ridge augmentation, maxillary sinus augmentation, TMJ reconstruction, periodontal regeneration, periodontal/peri-implant plastic surgery, regenerative endodontics. In addition, polymeric scaffolds application in whole tooth and salivary gland regeneration are discussed.

Comparison of Bone Regeneration in Different Forms of Bovine Bone Scaffolds with Recombinant Human Bone Morphogenetic Protein-2

The aim of this study was to compare the bone regeneration ability of particle and block bones, acting as bone scaffolds, with recombinant human bone morphogenetic protein (rhBMP)-2 and evaluate them as rhBMP-2 carriers. Demineralized bovine bone particles, blocks, and rhBMP-2 were grafted into the subperiosteal space of a rat calvarial bone, and the rats were randomly divided into four groups: particle, block, P (particle)+BMP, and B (block)+BMP groups. The bone volume of the B+BMP group was significantly higher than that of the other groups (p < 0.00), with no significant difference in bone mineral density. The average adipose tissue volume of the B+BMP group was higher than that of the P+BMP group, although the difference was not significant. Adipose tissue formation was observed in the rhBMP-2 application group. Histologically, the particle and B+BMP groups showed higher formation of a new bone. However, adipose tissue and void spaces were also formed, especially in the B+BMP group. Hence, despite the formation of a large central void space, rhBMP-2 could be effectively used with block bone scaffolds and showed excellent new bone formation. Further studies are required to evaluate the changes in adipose tissue.

Using Cone-Beam Computed Tomography to Assess Changes in Alveolar Bone Width around Dental Implants at Native and Reconstructed Bone Sites: A Retrospective Cohort Study

The aim of this study was to use a cone-beam computed tomography (CBCT) to assess changes in alveolar bone width around dental implants at native and reconstructed bone sites before and after implant surgery. A total of 99 implant sites from 54 patients with at least two CBCT scans before and after implant surgery during 2010–2019 were assessed in this study. Demographic data, dental treatments and CBCT scans were collected. Horizontal alveolar bone widths around implants at three levels (subcrestal width 1 mm (CW1), subcrestal width 4 mm (CW4), and subcrestal width 7 mm (CW7)) were measured. A p-value of < 0.05 indicated statistically significant differences. The initial bone widths (mean ± standard deviation (SD)) at CW1, CW4, and CW7 were 6.98 ± 2.24, 9.97 ± 2.64, and 11.33 ± 3.00 mm, respectively, and the postsurgery widths were 6.83 ± 2.02, 9.58 ± 2.55, and 11.19 ± 2.90 mm, respectively. The change in bone width was 0.15 ± 1.74 mm at CW1, 0.39 ± 1.12 mm at CW4 (p = 0.0008), and 0.14 ± 1.05 mm at CW7. A statistically significant change in bone width was observed at only the CW4 level. Compared with those at the native bone sites, the changes in bone width around implants at reconstructed sites did not differ significantly. A significant alveolar bone width resorption was found only at the middle third on CBCT scans. No significant changes in bone width around implants were detected between native and reconstructed bone sites.

Clinical and radiographical performance of implants placed with simultaneous guided bone regeneration using resorbable and nonresorbable membranes after 22-24 years, a prospective, controlled clinical trial

Aim

The aim was to evaluate the performance of implants placed with simultaneous guided bone regeneration (GBR) using resorbable or nonresorbable membranes compared to implants placed in pristine bone without bone regeneration after an observation period of 22–24 years.

Material and Methods

The patient cohort of this clinical trial was treated from 1994 to 1996. Dehiscence defects were treated with GBR by either using resorbable collagen membranes (BG) or nonresorbable ePTFE membranes (GT). Implants placed in pristine bone served as a control (CT). Clinical parameters, marginal bone levels, and technical outcomes were evaluated following restoration placement and at the present follow‐up. A 3D radiographic analysis was conducted in order to assess buccal and oral bone dimensions. Implant survival was assessed with Kaplan–Meier analysis and a frailty model (level of significance 5%).

Results

Out of the originally 72 patients (mean age 75.4 ± 15.70 years) with 265 implants, 39 patients with 147 implants were included in the study after a median period of 23.5 years. Implant survival was 89.3% in group BG (n = 100), 90.2% in group GT (n = 37), and 93.8% in group CT (n = 105), without significant differences (Frailty proportional hazard model p = .79). Smoking had a negative effect on survival (p = .0122). Mean vertical marginal bone levels were −2.3 ± 1.4 mm (BG, n = 59), −3.0 ± 1.5 mm (GT, n = 21), and −2.3 ± 1.6 mm (CT, n = 52). The vertical buccal bone levels were −3.0 ± 1.9 mm (BG, n = 57), −3.5 ± 2.2 mm (GT, n = 21), and −2.6 ± 1.8 mm (CT, n = 49), without significant differences.

Conclusion

Implant placement with GBR procedures provides treatment outcomes with favorable implant survival rates (89.3%–93.8%) after 23.5 years. Smoking, however, affected implant survival negatively.

Bone Morophogenetic Protein Application as Grafting Materials for Bone Regeneration in Craniofacial Surgery: Current Application and Future Directions

ABSTRACT

Rebuilding atrophied alveolar ridges can present a significant challenge for the maxillofacial surgeons. A multitude of treatment options including guided bone regeneration, onlay block grafting, and distraction osteogenesis are today available as safe procedures.The recent Food and Drug Administration approval of recombinant human bone morphogenetic proteins (rhBMPs) has given clinicians an added treatment option for reconstructing localized and large jaw defects. Currently, several patients have been successfully treated with the combination of bone graft and rhBMP-2 and the results have been documented as predictable and safe by clinical and radiologic examinations follow-up. In this study, a literature review was conducted using Medline, Medpilot, and Cochrane Database of Systematic Reviews. It was concentrated on manuscripts and overviews published in the last 20 years (2000-2020). The key terms employed were platelet-rich plasma, rhBMPs, and their combinations with the common scaffolds used for bone regeneration techniques. The results of clinical studies and animal trials were especially emphasized. The statements from the literature were compared with authors' own clinical data.The potential to reconstruct these large bone defects with a growth factor thus limiting or even avoiding a secondary harvest site is exciting and it represents a new frontier in the field of surgery. This study data confirm how there are excellent documents about the possible combination of using substitute materials and growth factor for treating large and minor craniofacial bone defects.

Effectiveness of xenogeneic and synthetic bone-block substitute materials with/without recombinant human bone morphogenetic protein-2: A preclinical study using a rabbit calvarium model

AIM

To investigate new bone (NB) formation by using bone-block substitute materials with/without recombinant human bone morphogenetic protein-2 (rhBMP-2).

MATERIALS AND METHODS

Three synthetic bone-block substitute materials [biphasic calcium phosphate (BCP); nanostructured hydroxyapatite (NH); 3D-printed tricalcium phosphate/hydroxyapatite (3DP)] and one xenogeneic deproteinized bovine bone mineral (DBBM) block substitute were affixed to rabbit calvarium using osteosynthesis screws, either with rhBMP-2 (n = 12) or without rhBMP-2 (n = 16). At 2 or 12 weeks (n = 6 with rhBMP-2 and n = 8 without rhBMP-2 for each week), histologic, histomorphometric and microcomputed tomography analyses were performed.

RESULTS

The application of rhBMP-2 increased NB formation in all experimental groups at both weeks. DBBM resulted in a greater area of NB compared with synthetic blocks either with or without rhBMP-2 at 2 weeks (2.8 ± 0.9 vs. 1.4 ± 0.5-1.9 ± 1.4 mm² ; 1.4 ± 1.0 vs. 0.6 ± 0.3-0.9 ± 0.5 mm² ) and without rhBMP-2 at 12 weeks (3.0 ± 0.8 vs. 1.7 ± 0.7-2.6 ± 1.5 mm² ) (p > 0.05). NB formation did not differ significantly for DBBM and the three types of synthetic block with rhBMP-2 at 12 weeks (4.5 ± 2.0 vs. 3.8 ± 0.7-5.1 ± 1.1 mm² ; p > 0.05).

CONCLUSIONS

rhBMP-2 enhanced NB in all blocks. DBBM blocks yielded more NB than synthetic blocks without rhBMP-2. The application of rhBMP-2 appears to compensate for differences in late healing.

Volumetric changes at implant sites: A systematic appraisal of traditional methods and optical scanning-based digital technologies

AIM

To evaluate techniques for assessing soft tissue alterations at implant sites and compare the traditionally utilized methods to the newer three-dimensional technologies emerging in the literature.

MATERIALS AND METHODS

A comprehensive search was performed to identify interventional studies reporting on volumetric changes at implant sites following different treatments.

RESULTS

Seventy-five articles were included the following: 30 used transgingival piercing alone, one utilized calliper, six with ultrasonography, six on cone-beam computed tomography, and 32 utilized optical scanning and digital technologies. Optical scanning-based digital technologies were the only approach that provided 'volumetric changes,' reported as volumetric variation in mm³ , or the mean distance between the surfaces/mean thickness of the reconstructed volume. High variability in the digital analysis and definition of the region of interest was observed. All the other methods reported volume variation as linear dimensional changes at different apico-coronal levels. No studies compared volumetric changes with different approaches.

CONCLUSIONS

Despite the emergence of optical scanning-based digital technologies for evaluating volumetric changes, a high degree of variation exists in the executed workflow, which renders the comparison of study results not feasible. Establishment of universal guidelines could allow for volumetric comparisons among different studies and treatments.

Clinical performance of alveolar ridge augmentation with xenogeneic bone block grafts versus autogenous bone block grafts. A systematic review

INTRODUCTION

This systematic literature review aimed to evaluate the feasibility of xenogeneic bone blocks for ridge augmentation compared with autogenous blocks by analyzing block survival rates, block resorption, subsequent implant survival rate, post-surgical complications, and histomorphometric findings.

MATERIALS AND METHODS

Electronic searches were conducted in the Medline (PubMed), Web of Science and Cochrane databases, complimented by a manual search in specialist journals, for relevant articles published up to March 2020. Inclusion criteria were human studies in which the outcomes of xenogeneic bone block grafts were evaluated by means of their survival rates and subsequent implant survival rates.

RESULTS

Sixteen articles fulfilled the inclusion criteria and were analyzed. 333 patients were recruited with a total of 337 xenogeneic bone blocks and 82 autogenous bone blocks, showing block failure rates of 6.82% and 6.1%, respectively. Bone gain, in both height and width, was similar among xenogeneic and autogenous bone blocks, but autogenous bone blocks suffered greater resorption. Implant survival rates were slightly lower for xenogeneic bone blocks. Histological and histomorphometric analysis observed more bone formation and less residual bone substitute with autogenous bone blocks than xenogeneic bone blocks.

CONCLUSIONS

Atrophic alveolar crest reconstruction with xenogeneic bone block grafts would appear to offer a viable alternative to autogenous bone block grafts, obtaining similar block graft failure rate, fewer sensitive postoperative complications but a slightly lower implant survival rate. Further investigations generating long term data are needed to confirm the feasibility of xenogeneic bone blocks in different clinical scenarios.

Clinical applications of avian eggshell-derived hydroxyapatite

The search for bone reconstruction materials and methods is an ongoing challenge. The aim of this review is to systemically search the available literature concerning the clinical performance of eggshell as a substitute material in guided bone regeneration in oral surgery. Five databases (PubMed, Cochrane, Web of Science, Scopus, and Embase) were searched up to February 2020. Clinical trials that used eggshell as a bone substitute material were included in the review. Animal and in vivo studies were excluded from the review. ROBINS-I was used to evaluate the risk of bias. A total of 840 studies were retrieved, out of which 55 full-text articles were screened. Five studies were finally included: one study showed critical and four serious risk of bias. A total of 74 patients and 88 intervention sites were included in the five studies. Clinical and radiological evaluation showed complete healing during the follow-ups. Statistically significant radiological and clinical evidence of new bone formation was achieved for socket preservation, grafting after third molar extraction, and cystic/apicectomy grafting. One patient with complications was reported. Histological analysis and micro computed tomography confirmed that it promotes bone regeneration. A comparison with synthetic hydroxyapatite showed similar healing characteristics. Within the limitations of the included studies, the eggshell can be safely and efficiently used in guided bone regeneration procedures, but more research is needed to completely evaluate the full potential of this material.