Bone substitutes and growth factors as an alternative/complement to autogenous bone for grafting in implant dentistry

Regeneration of Chronic Alveolar Vertical Defects Using a Micro Dosage of rhBMP-2. An Experimental In Vivo Study

OBJECTIVE

The objective of this study is to compare the effect of the location of recombinant human bone morphogenetic protein 2 (rhBMP-2) from the native bone and the periosteum for vertical alveolar bone augmentation.

MATERIALS AND METHODS

Mandibular, chronic, standardized, bilateral, and vertical defects in 12 beagle dogs were evaluated using four modalities: a xenograft alone (XENO; n = 6); rhBMP-2 alone (BMP; n = 6); a technique with rhBMP-2 close to the host bone covered by xenograft (SAN; n = 6); and a technique with rhBMP-2 close to the flap on top of the xenograft (LAS; n = 6). After 8 weeks, a series of in vivo inspections, fluorescence microscopy, histologic and histomorphometric evaluations, and micro-CT analyses.

RESULTS

After 8 weeks of healing, new bone formation correlated with proximity of rhBMP to the perforated membrane with BMP and LAS (p = 0.024). The highest total bone volume was found in the LAS group (45.1% ± 13.3%), followed by the SAN group (35.2% ± 6.7%), BMP group (33.1% ± 11.8%), followed by the XENO group (23.1% ± 6.5%). The SAN group demonstrated frequent seroma formation. Blood vessel formation was more pronounced in the LAS + rhBMP group, with a significant increase of 27.1% compared to the XENO group (p = 0.02). Micro-CT revealed a strong trend for higher bone volume in the BMP group (34.7%) compared to the XENO group (13.6%) (p = 0.06). Only rhBMP-2 groups demonstrated bone formation above the perforated membrane.

CONCLUSION

The location of rhBMP-2 in relation to the biomaterial and periosteum influenced the effectiveness of vertical bone regeneration.

Two Stage Sinus Lifting Using Nanohydroxyapatite Particles Versus Deproteinized Bovine Bone: Randomized Clinical Trial

BACKGROUND

Sinus floor elevation is one of the predictable techniques for augmentation of vertically deficient posterior maxillary alveolar ridges. Several biomaterials were reported to be successful for sinus augmentation, including xenografts and hydroxyapatite. The aim of this study was to compare the quality and quantity of generated bone using xenografts versus nanohydroxyapatite in sinus augmentation.

METHODOLOGY

Twenty-four patients/sinuses were randomly assigned into two groups; in the control group, patients underwent sinus floor elevation and augmentation using deproteinized bovine bone (DBB), whereas in the study group, the sinus was augmented using nanohydroxy-apatite bone (NHA). For each patient, the amount of bone height was assessed preoperatively, immediately postoperatively, and 6 months postoperatively. Furthermore, the quality of the newly formed bone was assessed via histological and histomorphometric analyses after 6 months postoperatively.

RESULTS

Both biomaterials showed a good level of consolidation. In the study group, the mean bone height after 6 months was 11.72 ± 1.24 compared to 12.01 ± 1.16 mm in the control group which was not statistically significant (p > 0.05). The mean bone area percent of newly formed bone was 29.84% ± 6.7% for NHA group and 34.73 ± 7.9 for DBB group. Moreover, the mean percent of residual grafting material was 32.43% ± 11.53% for NHA group compared to 30.43% ± 8.27% for DBB group. Histologically, there was no significant difference between both groups regarding different parameters (p > 0.05).

CONCLUSION

The two-stage sinus floor augmentation using NHA and DBB revealed no statistically significant difference regarding both the quality and the quantity of the regenerated bone. Studies with larger samples and longer follow up are recommended.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03184857.

Comprehensive three-dimensional cone beam computed tomography assessment unilateral alveolar cleft reconstruction using autologous iliac cancellous bone combined with deproteinized bovine bone: A clinical retrospective evaluation

Large-volume autologous iliac cancellous bone grafting for alveolar cleft may lead to undesirable bone resorption and susceptible donor-site morbidity, whereas the addition of deproteinized bovine bone (DBB) could optimize outcomes. This study aimed to evaluate the effectiveness of combining autologous iliac bone with DBB using three-dimensional cone beam computed tomography (3D-CBCT) for better analysis of bone generation than conventional evaluation methods. Thirty-six patients with unilateral alveolar cleft were assigned into two groups. Group A (n = 21) underwent autogenous cancellous bone graft harvested from the anterior iliac crests, while Group B (n = 15) received a composite of autogenous iliac cancellous bone and DBB. Patients in Group B displayed higher bone filling rates (P < 0.0001) and lower bone absorption rates (P < 0.001) than those in Group A at both 6 months and 1 year postoperatively. Additionally, there were directional differences in bone absorption within the bone grafts, with more absorption observed on the alveolar crest and palatal sides than that on the nasal and labial sides (P < 0.001). This study demonstrates that employing a combination of DBB and autologous bone in alveolar cleft repair achieves better outcomes of bone grafting.

Experimental long bone fracture healing in goats with cockle shell-based calcium carbonate bone paste

Long bone fractures are common orthopedic conditions. There are numerous ways to repair these fractures. Bone grafting becomes necessary when a broken bone has a significant gap. However, due to insufficient donor volume and donor site morbidity, substitutes are required. In veterinary orthopaedics, calcium carbonate from cockle shells could be used as a bone biomaterial. We investigated its efficacy as a bone biomaterial repair for goat femoral fractures. The study included 10 healthy adult male Black Bengal goats weighing 8 kg and aged 12-13 months. The study includes control and treatment groups. Intramedullary pinning stabilized an 8-mm right femur diaphyseal fracture in the treatment and control groups. The treated group received 2 ml of bone paste in the fractured gap, whereas the control group left it empty. We examined all goats with X-rays on the 7th, 45th, and 60th days, followed by gross and histological findings. Due to callus bridging, radiographs revealed faster bone growth in the treated group than in the control group. Gross examination demonstrates the treated group had a larger fracture callus than the control group. Histopathology showed that bone formed faster and included more osteocytes, osteoblasts, osteoclasts, and bony spicules than in the control group. The treated group had more periosteum osteoblasts, while the control group had fibroblasts. These results showed that the treated group had more osteogenic activity than the control group. This study demonstrates the potential of cockle shell-based calcium carbonate bone paste as a synthetic biomaterial for healing long bone fractures in goats.

Immediate implant placement and simultaneous bone grafting with bone cement in extraction sockets: A systematic review

Background

The placement of immediate dental implants intrinsically displays crestal gaps, which may compromise implant osseointegration. Several grafting materials have been used to overcome this issue. Of the available materials, the use of bone cement is relatively new in oral implantology. This study aimed to examine the available literature on the utilization of bone cements in immediate placement of dental implants and assess its potential in oral implantology.

Objectives

To synthesize evidence for appraising the impact of bone cements on implant stability and bone-to-implant contact (BIC) of dental implants placed immediately after extraction in humans and animals after 3 months of healing from tooth extraction.

Methods

A systematic search was conducted in PubMed, Medline, and ScienceDirect for relevant studies published from inception to September 2021 using relevant search terms. Of the 1624 studies, 4 were selected for this systematic review.

Results

Three of the four studies concluded that bone cements enhanced implant stability and/or BIC with better quality and/or quantity of bone surrounding the immediate dental implant. The conclusion drawn by one article remained indecisive. Meta-analysis could not be performed owing to the presence of substantial heterogeneity.

Conclusion

Bone cement is a promising treatment alternative as it augments implant stability and/or BIC in immediate dental implants. Nonetheless, further prospective human clinical trials are required to establish its clinical effectiveness and arrive at a definitive conclusion to recommend its clinical use.

Combination of a Synthetic Bioceramic Associated with a Polydioxanone-Based Membrane as an Alternative to Autogenous Bone Grafting

The purpose of this study was to evaluate the repair process in rat calvaria filled with synthetic biphasic bioceramics (Plenum® Osshp-70:30, HA:βTCP) or autogenous bone, covered with a polydioxanone membrane (PDO). A total of 48 rats were divided into two groups (n = 24): particulate autogenous bone + Plenum® Guide (AUTOPT+PG) or Plenum® Osshp + Plenum® Guide (PO+PG). A defect was created in the calvaria, filled with the grafts, and covered with a PDO membrane, and euthanasia took place at 7, 30, and 60 days. Micro-CT showed no statistical difference between the groups, but there was an increase in bone volume (56.26%), the number of trabeculae (2.76 mm), and intersection surface (26.76 mm2) and a decrease in total porosity (43.79%) in the PO+PG group, as well as higher values for the daily mineral apposition rate (7.16 µm/day). Histometric analysis presented material replacement and increased bone formation at 30 days compared to 7 days in both groups. Immunostaining showed a similar pattern between the groups, with an increase in proteins related to bone remodeling and formation. In conclusion, Plenum® Osshp + Plenum® Guide showed similar and sometimes superior results when compared to autogenous bone, making it a competent option as a bone substitute.

Effectiveness of Autologous Platelet Concentrates in the Sinus Lift Surgery: Findings from Systematic Reviews and Meta-Analyses

Maxillary sinus augmentation is one of the most predictable procedures for the rehabilitation of the posterior maxilla. The current overview aimed to summarize the findings provided by systematic reviews (SRs) and meta-analyses on the effectiveness of autologous platelet concentrates (APCs) in sinus lift and to assess the methodological quality of the included SRs. Three electronic databases have been explored. SRs and meta-analyses addressing the effectiveness of APCs in sinus lift technique were included. Clinical, radiographic and histomorphometric findings were considered for APCs as solely grafting materials and APCs in combination with biomaterials. Outcomes were implant survival rate (ISR), implant stability (IS), implant failure (IF), postoperative complications, histomorphometric findings, radiographic bone gain, bone volume and bone density. The methodological quality of the included SRs was assessed using the updated version of "A Measurement Tool to Assess Systematic Review" (AMSTAR-2). Thirty SRs were included. The methodological quality of the included reviews ranged from critically low (3 studies) to high (9 studies). The included SRs showed favorable clinical outcomes, short-term new bone formation and no biological complications when APCs were used both as solely graft material or in combination with other biomaterials. However, no significant additional effects in the long-term period were observed. APCs did not add any further positive effects compared to the physiological healing derived by the natural blood clot. The current overview of SRs highlighted the need for high-quality SRs evaluating the role of APCs in sinus lift though network meta-analyses, in order to identify the most powerful material for sinus lift augmentation. The use of APCs improves the healing of soft tissues and the postoperative quality of life in the short-term period. Thus, its application can be recommended.

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.

Tooth Graft: An Umbrella Overview

This umbrella review aims to evaluate systematic/meta-analysis studies containing clinical evidence on tooth grafts as bone substitutes in the oral and maxillofacial regions. Using language restrictions and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, an electronic database search of PubMed, MEDLINE, Embase, Cochrane library, and Google Scholar was conducted, featuring published studies up until August 2022. All systematic/meta-analysis review articles relating to tooth graft materials were matched against the inclusion criteria. Two qualified researchers independently assessed the studies' inclusion or exclusion criteria and risk of bias, and a third investigator assisted in resolving ambiguities. A total of 81 systematic/meta-analysis studies, comprising 21 animal-controlled trials, 23 randomized controlled human trials, 23 prospective studies, and 14 retrospective studies, were selected for this study. A small risk of bias was observed in systematic studies/meta-analyses. In addition, the clinical evidence from the analysis of these studies revealed a low incidence of side effects. According to the current review, two systematic reviews indicated that autogenous bone grafting of prepared teeth might be as effective as other bone grafting materials. Four studies also mentioned autologous grafts as potential alternatives to autologous grafts, autogenous demineralized dentin (ADDM), engineered grafts, root blocks, and dental matrix. On the other hand, three systematic studies stated that more long-term research is needed to confirm their findings. Finally, given the importance of standardization and homogeneity of studies for clinical cases, it is advised to be used cautiously due to the risks of transplant rejection.

Auto-dentin platelet-rich fibrin matrix is an alternative biomaterial for different augmentation procedures: A retrospective case series report

OBJECTIVES

Autologous dentin grafts derived from extracted teeth have shown promise as bone graft materials for promoting bone regeneration. This retrospective case series aimed to evaluate clinical, radiographic, and histologic outcomes of using autologous dentin matrices in various bone regeneration procedures.

MATERIALS AND METHODS

This case series included 26 eligible patients and encompassed 4 socket preservation cases, 5 cases of guided tissue regeneration, 5 cases of guided bone regeneration (GBR), 10 cases of sinus augmentation procedures, 2 immediate placement implants, and 2 socket shields. Dentin grafts were prepared from extracted teeth, cleaned, and processed. These grafts were combined with platelet-rich fibrin (PRF) to create adhesive dentin matrices, then covered with collagen membranes for simultaneous guided bone augmentation cases. Cone beam computed tomography (CBCT) scans were conducted before surgery and 4 months postoperatively to assess ridge dimensions. Histologic evaluation was performed through bone core biopsies for socket preservation cases at the 4-month mark.

RESULTS

A total of 42 implants were placed in 26 patients, with an average follow-up of 32 months. Notably, two implant failures occurred following lateral maxillary sinus augmentation. CBCT scans at the 4-month interval revealed bone coverage over implant platforms in the majority of cases. Histologic analysis from two cases of socket preservation demonstrated dentin granules enveloped by newly formed bone undergoing continuous remodeling. The quantitative histomorphometric assessment revealed a bone area of 42.8 ± 3.56%, a remaining graft area of 19.05 ± 4.58%, and a viable bone of 38.15 ± 7.84%.

CONCLUSIONS

The utilization of autologous dentin particles mixed with PRF proved effective as an alternative to conventional bone graft materials in GBR and maxillary sinus augmentation procedures. Larger controlled clinical trials are recommended to further substantiate these findings.

Clinical, radiographic, and histological/histomorphometric analysis of maxillary sinus grafting with deproteinized porcine or bovine bone mineral: A randomized clinical trial

OBJECTIVE

The present study aimed to compare histomorphometrically evaluated new bone formation, radiographically measured graft stability, and clinical implant outcome between maxillary sinus grafting with either deproteinized porcine bone mineral (DPBM) or deproteinized bovine bone mineral (DBBM).

MATERIALS AND METHODS

Thirty maxillary sinuses were initially included and randomly assigned to the test group (TG; DPBM, n = 15) or control group (CG; DBBM, n = 15). After a healing period (6 months), axially retrieved bone biopsies of the molar region were used for histological/histomorphometric analysis of new bone formations. Additionally, radiographically measured graft stability and clinical implant outcome were assessed.

RESULTS

Twenty-three sinus sites with 10 sinuses of the TG and 13 of the CG were ultimately available for data and statistical analysis. In the TG, a slightly, but yet significantly (p = .040) higher proportion of new bone formation (TG: 27.7 ± 5.6% vs. CG: 22.9 ± 5.1%) and a lesser (p = .019) amount of connective (non-mineralized) tissue (TG: 47.5 ± 9.5% vs. CG: 56.1 ± 9.5%) was found than in the CG. However, both xenografts showed comparable (n.s.) residual bone graft (TG: 23.7 ± 7.2% vs. CG: 21.1 ± 9.85.6%), bone-to-graft contacts (TG: 26.2 ± 9.8% vs. CG: 30.8 ± 13.8%), similar graft height reduction over time (TG: 12.9 ± 6.7% CG: 12.4 ± 5.8%) and implant survival/success rate (100%). At the 3-year post-loading evaluation, the peri-implant marginal bone loss (TG: 0.52 ± 0.19 mm; CG: 0.48 ± 0.15 mm) and the peri-implant health conditions (TG: 87.5%/CG: 81.2%) did not differ between implants inserted in both xenografts used.

CONCLUSIONS

The use of DPBM or DBBM for maxillary sinus augmentation is associated with comparable bone formation providing stable graft dimension combined with healthy peri-implant conditions.

In vitro evaluation of granules obtained from 3D sphene scaffolds and bovine bone grafts: chemical and biological assays

Sphene is an innovative bone graft material. The aim of this study was to investigate and compare the physicochemical and biological properties of Bio-Oss® (BO) and in-lab synthesized and processed sphene granules. BO granules of 1000-2000 μm (BO-L), 250-1000 μm (BO-S) and 100-200 μm (BO-p) for derived granules, and corresponding groups of sphene granules obtained from 3D printed blocks (SB-L, SB-S, SB-p) and foams (SF-L, SF-S and SF-p) were investigated. The following analyses were conducted: morphological analysis, specific surface area and porosity, inductively coupled plasma mass spectrometry (ICP-MS), cytotoxicity assay, Alizarin staining, bone-related gene expression, osteoblast migration and proliferation assays. All pulverized granules exhibited a similar morphology and SF-S resembled natural bone. Sphene-derived granules showed absence of micro- and mesopores and a low specific surface area. ICP-MS revealed a tendency for absorption of Ca and P for all BO samples, while sphene granules demonstrated a release of Ca. No cellular cytotoxicity was detected and osteoblastic phenotype in primary cells was observed, with significantly increased values for SF-L, SF-S, BO-L and BO-p. Further investigations are needed before clinical use can be considered.

Photobiomodulation and Inorganic Bovine Bone in Guided Bone Regeneration: Histomorphometric Analysis in Rats

The objective of this study was to evaluate the efficacy of photobiomodulation in the bone regeneration of critical-sized defects (CSD) filled with inorganic bovine bone associated or not with collagen membranes. The study has been conducted on 40 critical defects in the calvaria of male rats, divided into four experimental groups (n = 10): (1) DBBM (deproteinized bovine bone mineral); (2) GBR (DBBM+collagen membrane); (3) DBBM+P (DBBM+photobiomodulation); and (4) GBR+P (GBR+photobiomodulation). At 30 days postoperative, the animals were euthanized, and after the tissue had been processed, histological, histometric, and statistical analyses were performed. The analyses have taken into account newly formed bone area (NBA), linear bone extension (LBE), and residual particle area (RPA) as variables. The Kruskal-Wallis test has been performed, followed by the Dwass-Steel-Critchlow-Fligner test for comparison between groups (p < 0.05). When the DBBM+P group was compared to the DBBM group, it was possible to observe significant statistical differences in all the variables analyzed (p < 0.05). The application of photobiomodulation in guided bone regeneration (GBR+P) has shown a decrease in the median value for the RPA variable (26.8) when compared to the GBR group (32.4), with a significant statistical difference; however, for NBA and LBE, the therapy has not provided significant results.

Healing of particulate allografts mixed with platelet concentrates in ridge preservation and sinus lift: a prospective histomorphometric study

The objective of the present study was to evaluate the bone quality of sinus and alveolar grafts following filling with particulate allogenous bone (DFDBA 300-500μm) and platelet concentrate (platelet-rich fibrin, PRF). A prospective interventional clinical study was carried out. A total of 40 bone cores, 2mm in diameter, were taken from 21 patients: 22 from grafted alveoli, 7 from grafted sinus sites, and 11 from native bone used as a control. Fixed, paraffin-embedded samples were subjected to histological staining with hematoxylin-eosin and Masson's trichrome. Bone maturity of the samples was evaluated by two independent operators using histomorphometric analysis. There existed a greater proportion of lamellar neoformed bone than woven neoformed bone as the healing time increased. Moreover, there was also an increasing proportion of newly formed bone in the grafted sockets as a function of healing time (average: 41.22% ≤ 5 months, 55.89% ˃ 5 months). Resorption of DFDBA particles also appears to be correlated with healing time in the grafted socket (average: 15.43 ≤ 5 months, 13.72% ˃ 5 months). In conclusion, performing sinus lift and alveolar socket preservation techniques using DFDBA and PRF results in high quality, mature bone tissue according to histological criteria.

CBCT Evaluation of Sticky Bone in Horizontal Ridge Augmentation with and without Collagen Membrane-A Randomized Parallel Arm Clinical Trial

Guided bone regeneration (GBR) is a reliable technique used to treat ridge deficiencies prior or during implant placement. Injectable-platelet rich fibrin (i-PRF) laced with a bone substitute (sticky bone) has heralded the way for advancing the outcomes of bone regeneration. This study evaluated the efficacy of sticky bone in horizontal ridge augmentation with and without collagen membrane. A total of 20 partially edentulous patients (Group-I n = 10; Group-II n = 10) that indicated GBR were included, and the surgical procedure was carried out. In Group-I, the sticky bone and collagen membrane were placed in ridge-deficient sites and Group-II received only sticky bone. At the end of 6 months, 20 patients (Group-I (n = 10); Group-II (n = 10)) completed the follow-up period. A CBCT examination was performed to assess changes in the horizontal ridge width (HRW) and vertical bone height (VBH). A statistically significant increase in HRW (p < 0.05) was observed in both groups with mean gains of 1.35 mm, 1.55 mm, and 1.93 mm at three levels (crest, 3 mm, and 6 mm) in Group-I and 2.7 mm, 2.8 mm, and 2.6 mm at three levels in Group-II. The intergroup comparison revealed statistical significance (p < 0.05) with respect to HRW and KTW (Keratinised tissue width) gains of 0.775 at the 6-month follow-up. Sticky-bone (Xenogenic-bone graft + i-PRF) served as a promising biomaterial in achieving better horizontal bone width gain.

Combined Effect of Platelet-Rich Fibrin Matrix (PRFM) and Demineralized Freeze-Dried Bone Allograft (DFDBA) in Immediate Implant Placement: A Single-Arm Clinical Trial

Introduction

Placement of immediate implants in contrast to delayed implant placement may be favorable. The factors contributing to this are shortened overall treatment time, aid in ideal orientation and fixture placement, bone preservation following extraction, and achieving optimal aesthetics involving soft tissue. However, the gap distance between the surface of the implant and the buccal bony wall during implant placement is critical for subsequent bone healing in a fresh extraction socket. Considering that as the gap broadens, the amount of bone-to-implant contact (BIC) decreases, causing an apical shift of the highest bone-implant contact. Incorporating a bone substitute material (BSM) within the fixture-socket gap preserves alveolar ridge volume by minimizing socket remodeling and encouraging de-novo bone formation.

Aim and objectives

To evaluate the efficacy of platelet-rich fibrin matrix (PRFM) and demineralized freeze-dried bone allograft (DFDBA) in fresh extraction socket with simultaneous implant placement.

Methods

Implants were immediately placed in 12 patients following a two-stage submerged protocol. The combination of PRFM and DFDBA was used to fill the gap between the implant body and the surrounding socket wall. The final restoration was placed after 3 months following implant placement. The full mouth plaque, gingival bleeding index, and gingival esthetics scores were assessed at baseline, 3, and 6 months. The crestal changes were evaluated using intraoral periapical radiographs (IOPA) at baseline, 3, and 6 months. Cone beam computed tomography (CBCT) images were obtained at baseline and 6 months after implant loading to analyze the buccolingual changes.

Results

At 6 months follow-up, the coronal bone remodeling detected on CBCT revealed a minimal (0.1 mm) narrowing of the alveolar ridge in a buccolingual direction, with a mean bone loss of 0.10+0.09, which was statistically non-significant (p > 0.05). Implant success was 100% at 6 months after loading as determined by Akbrektsson’s criteria for implant success.

Conclusions

The adjunctive use of PRFM with DFDBA following immediate implant placement yielded a significant reduction in bone resorption and maintenance of buccolingual dimensions.

Clinical and radiographic outcomes of dental implant after maxillary sinus floor augmentation with rhBMP-2/hydroxyapatite compared to deproteinized bovine bone

Objectives

This study aimed to evaluate the clinical and radiographic outcomes of early implant placement and functional loading in maxillary sinus floor augmentation (MSFA) using recombinant human bone morphogenetic protein 2/hydroxyapatite (rhBMP-2/HA) and to compare these outcomes with those of the conventional protocol in MSFA using deproteinized bovine bone (DBB).

Materials and methods

The rhBMP-2/HA and DBB groups consisted of 14 and 13 patients who underwent MSFA with BMP and DBB, respectively. After placement of 22 implants and 21 implants in the rhBMP-2/HA and DBB groups, respectively, abutment connections were performed 3 months after implant placement for the rhBMP-2/HA group and 6 months after implant placement for the DBB group. Changes in grafted sinus height (GSH), marginal bone loss (MBL), and implant stability were evaluated up to one year after functional loading.

Results

Survival rates for the rhBMP-2/HA and DBB groups after one year of functional loading were 90.9% and 90.5%, respectively. Both groups exhibited no significant time-course changes in GSH until one year of functional loading (rhBMP-2/HA, p = 0.124; DBB, p = 0.075). Although significant MBL occurred after one year of functional loading for both groups (rhBMP-2/HA, p < 0.001; DBB, p < 0.001), there were no significant differences in time-course changes in MBL between the two groups (p = 0.450). The mean implant stability quotient values in the rhBMP-2/HA and DBB groups were 75.3 and 75.4 after one year of functional loading, respectively, and there were no significant differences between the two groups (p = 0.557).

Conclusions

MSFA using rhBMP-2/HA allowed implant rehabilitation with early implant placement and functional loading and led to a comparable survival rate and implant stability after 1 year of functional loading with acceptable MBL and stable maintenance of GSH compared to the MSFA using DBB with 6 months of healing after implant placement.

3D Printed Strontium and Zinc Doped Hydroxyapatite Loaded PEEK for Craniomaxillofacial Implants

In this study, Strontium (Sr) and Zinc (Zn) doped-HA nanoparticles were synthesized and incorporated into polyetheretherketone (PEEK) up to 30 wt.% and processed by a novel approach i.e., fused deposition modelling (FDM) 3D printing for the production of patient specific cranial implants with improved bioactivity and the required mechanical performance. Filaments were produced via extrusion and subsequently 3D-printed using FDM. To further improve the bioactivity of the 3D-printed parts, the samples were dip-coated in polyethylene glycol-DOPA (PEG-DOPA) solution. The printing quality was influenced by filler loading, but was not significantly influenced by the nature of doped-HA. Hence, the printing conditions were optimized for each sample. Micro-CT and Scanning Electron Microscopy (SEM) showed a uniform distribution of bioceramic particles in PEEK. Although agglomeration of particles increased with increase in filler loadings. Differential Scanning Calorimetry (DSC) showed that the melting point and crystallinity of PEEK increased with an increase in doped-HA loading from 343 °C to 355 °C and 27.7% to 34.6%, respectively. Apatite formation was confirmed on the 3D-printed samples after immersion in simulated body fluid (SBF) for 7, 14 and 28 days via SEM, X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR). The tensile strength and impact strength decreased from 75 MPa to 51 MPa and 14 kJ/m2 to 4 kJ/m2, respectively, while Young's modulus increased with increasing doped-HA content from 2.8 GPa to 4.2 GPa. However, the tensile strengths of composites remained in the range of human cortical bone i.e., ≥50 MPa. In addition, there was a slight increase in mechanical strength after 28 days immersion which was attributed to apatite formation. Water contact angle showed that the hydrophilicity of the samples improved after coating the 3D-printed samples with PEG-DOPA. Hence, based on the results, the 3D-printed PEEK nanocomposites with 20 wt.% doped-HA is selected as the best candidate for the 3D-printing of craniomaxillofacial implants.

Optimal Parameters of Laser Therapy to Improve Critical Calvarial Defects

Body bones play diverse pivotal roles, including the protection of vital organs. For instance, the integrative functions of the brain controlling diverse peripheral actions can be affected by a traumatic injury on the calvaria and the reparative process of a large defect is a challenge in the integrative physiology. Therefore, the development of biomaterials and approaches to improve such defects still requires substantial advances. In this regard, the most attractive approaches have been covering the cavity with inorganic bovine bone (IBB) and, more recently, also using low-level laser therapy (LT), but this issue has opened many questions. Here, it was determined the number of LT sessions required to speed up and to intensify the recovery process of two 5-mm-diameter defects promoted in the calvaria of each subgroup of six adult Wistar rats. The quantitative data showed that 30 days post-surgery, the recovery process by using blood clot-filling was not significantly influenced by the number of LT sessions. However, in the IBB-filled defects, the number of LT sessions markedly contributed to the improvement of the reparative process. Compared to the Control group (non-irradiated), the percentage of mineralization (formation of new bone into the cavities) gradually increased 25, 49, and 52% with, respectively, 4, 7, and 11 sessions of LT. In summary, combining the use of IBB with seven sessions of LT seems to be an optimal approach to greatly improve the recovery of calvarial defects. This translational research opens new avenues targeting better conditions of life for those suffering from large bone traumas and in the present field could contribute to preserve the integrative functions of the brain.

Evaluation of the Efficacy of Mineralized Dentin Graft in the Treatment of Intraosseous Defects: An Experimental In Vivo Study

Background and Objectives: Dentin grafts have osteoinductive and osteoconductive properties and are considered as an alternative to autogenous graft. This study evaluates the efficacy of autogenous mineralized dentin graft (AMDG) alone or with xenograft and compares it with those of various graft materials used in the treatment of intraosseous bone defects. Materials and Methods: The third incisor teeth of six sheep (2–3 years old) were extracted and AMDG was obtained. Six defects were prepared on each tibia of these six sheep: empty defect (group E); autogenous graft (group A), dentin graft (group D), xenograft (group X), autogenous + xenograft (group A + X) and dentin + xenograft (group D + X). Three sheep in each group were sacrificed in the post-operative 3rd and 6th week and the histologic analyses were performed. Results: The D and D + X groups showed histological features similar to the other groups in the 3rd and 6th weeks. No statistically significant difference was found regarding the rates of new bone formation between the D and D + X groups (p = 1.0) and the other groups at both time intervals (p > 0.05). Conclusions: Similar results observed in this study between groups A, D, X, A + X and D + X demonstrate that AMDG can be successfully used in the treatment of intraosseous bone defects. Further experimental and clinical studies are needed to be able to evaluate the effectiveness of dentin grafts in different types of indications.

Alendronato de sódio tópico associado ao osso bovino liofilizado no reparo ósseo

Resumo Introdução O osso bovino inorgânico é o enxerto mais utilizado na Odontologia, tendo como desvantagem longo tempo de integração ao leito receptor. Os bifosfonatos têm sido utilizados para modular a quantidade e a qualidade do osso regenerado e diminuir o tempo de integração do enxerto. Objetivo Avaliar o efeito do bifosfonato alendronato de sódio (ALN) 0,5%, associado ou não ao osso bovino inorgânico, na reparação de defeitos ósseos. Material e método Dois defeitos ósseos foram confeccionados na calvária de 12 coelhos, sendo a cavidade esquerda/experimental preenchida com: GI = osso bovino inorgânico (Bio-Oss®); GII = Bio-Oss® + ALN 0,5%; GIII = ALN 0,5%; e a cavidade direita por coágulo sanguíneo (controle). Os animais foram mortos aos 60 dias pós-operatórios. Por meio de análise histomorfométrica calculou-se o percentual de osso neoformado e remanescente do biomaterial em relação à área total do defeito. Resultado Osso neoformado: GI = 38,16 ± 15,44%; GII = 55,77 ± 16,75%; GII I = 60,28 ± 11,45%. Controle = 45,11 ± 11,09%. Remanescente do enxerto: GI = 7,02 ± 5,36% e GII = 16,59 ± 9,56%. Não houve diferença quanto ao percentual de osso neoformado entre os grupos (ANOVA p = 0,15512; teste de Tukey F = 2,089). O percentual de remanescente do enxerto também foi estatisticamente semelhante entre os grupos GI e GII (teste de Tukey F = 5,019). Conclusão O uso tópico da solução de ALN 0,5% isoladamente ou associado ao osso bovino liofilizado não alterou o percentual de neoformação óssea nem a degradação dos grânulos do enxerto.

Assessment of the Effects of Si Addition to a New TiMoZrTa System

Ti-based alloys are widely used in medical applications. When implant devices are used to reconstruct disordered bone, prevent bone resorption and enhance good bone remodeling, the Young's modulus of implants should be close to that of the bone. To satisfy this requirement, many titanium alloys with different biocompatible elements (Zr, Ta, Mo, Si etc.) interact well with adjacent bone tissues, promoting an adequate osseointegration. Four new different alloys were obtained and investigated regarding their microstructure, mechanical, chemical and biological behavior (in vitro and in vivo evaluation), as follows: Ti₂₀Mo₇Zr₁₅Ta, Ti₂₀Mo₇Zr₁₅Ta_0.5Si, Ti₂₀Mo₇Zr₁₅Ta_0.75Si and Ti₂₀Mo₇Zr₁₅TaSi. 60 days after implantation, both in control and experimental rabbits, at the level of implantation gap and into the periimplant area were found the mesenchymal stem cells which differentiate into osteoblasts, then osteocytes and osteoclasts which are involved in the new bone synthesis and remodeling, the periimplant fibrous capsule being continued by newly spongy bone tissue, showing a good osseointegration of alloys. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay confirmed the in vitro cytocompatibility of the prepared alloys.

Recombinant factors for periodontal intrabony defects: A systematic review and network meta-analysis of preclinical studies

The use of bioactive agents combined with osteoconductive scaffolds for the regeneration of periodontal intrabony defects has been the subject of intensive research in the past 20 years. Most studies reported that such agents, used in different concentrations, doses and combined with various scaffolds, might promote periodontal tissue regeneration, but evidence for the most effective combination of such agents is lacking. The objective of this study 13 was to rank the different combinations of recombinant human-derived growth and differentiation factors with/without scaffold biomaterial in the treatment of periodontal intrabony defects, through network meta-analysis of pre-clinical studies. The systematic review and network meta-analysis protocol was registered on the PROSPERO Systematic Review database with reference number: CRD42021213673. Relevant published articles were obtained after searching five electronic databases. A specific search strategy was followed by using keywords related to intrabony defects, regenerative materials, scaffolds and recombinant factors, and animal studies. All pre-clinical studies used for periodontal regeneration were included. The primary outcomes were: regeneration of junctional epithelium (mm), new cementum, connective tissue attachment, percentage of new bone formation (%), bone area (mm² ), bone volume density (g/cm³ ) and bone height (mm) data was extracted. The analysis was carried out using network meta-analysis methods, that is illustrating network plots, contribution plots, predictive and confidence interval plot, surface under the cumulative ranking (SUCRA), multidimensional scale ranking and net funnel plots using STATA IC statistical software. An SYRCLE's tool for assessing risk of bias was used for reporting risk of bias among individual studies. A total of N = 24 for qualitative and N = 21 studies for quantitative analysis published till 2020 were included. The cumulative total number of animals included in the control and test groups were N = 162 and N = 339, respectively. The duration of the study was between 3 and 102 weeks rhBMP-2 ranked higher in SUCRA as the agent associated with the best performance for bone volume density. rhGDF-5/TCP ranked best in the bone area (mm2), rhPDGF-BB/Equine ranked best in bone height (mm), rhBMP-2 ranked best in the percentage of new bone fill, rhBMP-2/ACS ranked best in new cementum formation, and rhGDF-5/b- TCP/PLGA ranked best in connective tissue attachment and junctional epithelium. There were no adverse effects identified in the literature that could affect the different outcomes for regeneration in intrabony defects. Various recombinant factors are effective in promoting the regeneration of both soft and hard tissue supporting structures of the periodontium. However, when considering different outcomes, different agents, associated or not with biomaterials, ranked best. Keeping into account the limited transferability of results from animal studies to the clinical setting, the choice of the most appropriate formulation of bioactive agents may depend on clinical needs and purpose.

Biofunctionalization of bioactive ceramic scaffolds to increase the cell response for bone regeneration

Biofunctionalization was investigated for polymers and metals considering their scarce integration ability. On the contrary few studies dealt with ceramic biofunctionalization because the bioactive and bioresorbable surfaces of ceramics are able to positively interact with biological environment. In this study the cell-response improvement on biofunctionalized wollastonite and diopside-based scaffolds was demonstrated. The ceramics were first obtained by heat treatment of a silicone embedding reactive oxide fillers and then biofunctionalized with adhesive peptides mapped on vitronectin. The most promisingin vitroresults, in terms of h-osteoblast proliferation and bone-related gene expression, were reached anchoring selectively a peptide stable toward proteolytic degradation induced by serum-enriched medium. Inin vivoassays the anchoring of this protease-stable adhesive peptide was combined with self-assembling peptides, for increasing cell viability and angiogenesis. The results demonstrated external and internal cell colonization of biofunctionalized scaffolds with formation of new blood vessels (neoangiogenesis) and stimulation of ectopic mineralization.

Patients' Perspectives of Grafting Materials in Implant Dentistry: A Qualitative Analysis

AIMS

The aim of this study was to evaluate the cultural, psychological, and religious influences on the choice of autografts, allografts, xenografts, and synthetic bone products for the grafting procedure and with implant placement.

MATERIALS AND METHODS

A qualitative methodology was employed, using the principles of the constant comparative method of the grounded theory; to investigate how people perceive and understand their experiences regarding the graft materials in implant dentistry. The data were collected using detailed qualitative interviews, till saturation was achieved, from 10 patients.

RESULTS

The three main themes that emerged in the analysis were: (a) grafting material preference, (b) religious and psychological influences, and (c) trust the doctor and cost influences. The three themes that emerged seemed to be interrelated. There were many statements of preference or rejection of choice based on religious, cultural, and psychological influences.

CONCLUSIONS

Within the limitations of this study, three themes emerged and they indicated that the influence on the grafting material's choice is unique to every individual; it also shares similarities, based on common religious and cultural values.

Biosilicated collagen/β-tricalcium phosphate composites as a BMP-2-delivering bone-graft substitute for accelerated craniofacial bone regeneration

BACKGROUND

Bioceramic β-tricalcium phosphate (β-TCP) is used as a bone-grafting material and a therapeutic drug carrier for treatment of bone defects in the oral and maxillofacial regions due to the osteoconductivity and biocompatibility. However, the low mechanical strength and limited osteoinductivity of β-TCP agglomerate restrict bone regenerating performance in clinical settings.

METHODS

Herein, a biomimetic composite is proposed as a bone morphogenetic protein-2 (BMP-2)-delivering bone graft substitute to achieve a robust bone grafting and augmented bone regeneration.

RESULTS

The sequential processes of brown algae-inspired biosilicification and collagen coating on the surface of β-TCP enable the effective incorporation of BMP-2 into the coating layer without losing its bioactivity. The sustained delivery of BMP-2 from the biosilicated collagen and β-TCP composites promoted in vitro osteogenic behaviors of pre-osteoblasts and remarkedly accelerated in vivo bone regeneration within a rat calvarial bone defect.

CONCLUSIONS

Our multicomposite bone substitutes can be practically applied to improve bone tissue growth in bone grafting applications with further expansion to general bone tissue engineering.

Influence of bone formation by composite scaffolds with different proportions of hydroxyapatite and collagen

Composite scaffolds with different proportions of hydroxyapatite (HA) and collagen (COL) produced different bone induction results.

OBJECTIVE

To examine the composite scaffolds with optimal proportion of HA and COL to achieve earlier bone induction and maximum bone formation.

METHODS

Composite scaffolds with the HA/COL weight ratio of 7:3, 3:7, 5:5 and 9:1 were prepared, as HA powder was added to collagen solution at 130℃ for 48 h. Then, the composites with different proportions of HA/COL were implanted into the extraction socket of right upper central incisor of C57BL/6 J mice. The bone formation of the extraction socket was observed by Hematoxylin-eosin (HE) and Masson-trichrome (Masson) staining at 1 and 2 weeks after operation. Five weeks later, the bone formation of extraction socket was observed by micro computed tomography (micro-CT). After MC3T3-E1 cells were co-cultured with materials of different proportions for 3 days, the number of cells attached on the surface of the materials and entering the materials were counted, and the expression of osteogenic related genes (Runx2, Ocn. Osx and Alp) was detected by reverse transcription polymerase chain reaction (RT-PCR). The composite scaffolds with different proportion of HA/COL with and without mouse bone marrow mesenchymal stem cells (BMMSCs) were implanted into the back of adult mice and cultured subcutaneously for 30 days, and observed histologically by HE and Masson staining.

RESULTS

After one week implantation with the composite HA/COL scaffolds with the weight ratio of 7:3, 3:7, 5:5 and 9:1, there was no new bone formation in the extraction socket in mouse. However, two weeks later, new bone was firstly observed in the tooth socket with the composite HA/COL scaffolds of 7:3. 5 weeks later, micro-CT scanning showed that the total amount of newly formed bone, trabecular width and bone mineral density of the HA/COL scaffolds of 7:3 were higher than the other HA/COL scaffolds (P < 0.05). After MC3T3-E1 cells were co-cultured with different composite HA/COL scaffolds for 3 days. The number of cells on the surface and inside of the HA/COL scaffolds of 7:3 was more than the other materials, and the difference was statistically significant (P < 0.05). The expression levels of Ocn and Osx of MC3T3-E1 cells were also the highest in the HA/COL scaffolds of 7:3 (P < 0.01). Bone formation was observed in the composite HA/COL scaffold of 7:3 with BMMSCs subcutaneously in mouse for 30 days, while only osteoid formation was observed in the same scaffold without BMMSCs. but bone formation was not detected in the other proportions of the HA/COL scaffolds.

SIGNIFICANCE

Compared with other proportions of HA/COL, the composite HA/COL scaffolds of 7:3 has stronger ability to promote bone formation, recruit osteoblasts to attach and enter into the scaffolds, and promote the osteogenesis of BMMSCs.

Guided bone regeneration of chronic non-contained bone defects using a volume stable porous block TiO2 scaffold: An experimental in vivo study

OBJECTIVES

To evaluate new lateral bone formation and lateral volume augmentation by guided bone regeneration (GBR) in chronic non-contained bone defects with the use of a non-resorbable TiO₂ -block.

MATERIALS AND METHODS

Three buccal bone defects were created in each hemimandible of eight beagle dogs and allowed to heal for 8 weeks before treatment by GBR. Each hemimandible was randomly allocated to 4- or 12-week healing time after GBR, and three intervention groups were assigned by block randomization: TiO₂ block: TiO₂ -scaffold and a collagen membrane, DBBM particles: Deproteinized bovine bone mineral (DBBM) and a collagen membrane, Empty control: Collagen membrane only. Microcomputed tomography (microCT) was used to measure the lateral bone formation and width augmentation. Histological outcomes included descriptive analysis and histomorphometric measurements.

RESULTS

MicroCT analysis demonstrated increasing new bone formation from 4 to 12 weeks of healing. The greatest width of mineralized bone was seen in the empty controls, and the largest lateral volume augmentation was observed in the TiO₂ block sites. The DBBM particles demonstrated more mineralized bone in the grafted area than the TiO₂ blocks, but small amounts and less than the empty control sites.

CONCLUSION

The TiO₂ blocks rendered the largest lateral volume augmentation but also less new bone formation compared with the DBBM particles. The most new lateral bone formation outward from the bone defect margins was observed in the empty controls, indicating that the presence of either graft material leads to slow appositional bone growth.

Feasibility of Application of the Newly Developed Nano-Biomaterial, β-TCP/PDLLA, in Maxillofacial Reconstructive Surgery: A Pilot Rat Study

This study was performed to examine the applicability of the newly developed nano-biocomposite, β-tricalcium phosphate (β-TCP)/u-HA/poly-d/l-lactide (PDLLA), to bone defects in the oral and maxillofacial area. This novel nano-biocomposite showed several advantages, including biocompatibility, biodegradability, and osteoconductivity. In addition, its optimal plasticity also allowed its utilization in irregular critical bone defect reconstructive surgery. Here, three different nano-biomaterials, i.e., β-TCP/PDLLA, β-TCP, and PDLLA, were implanted into critical bone defects in the right lateral mandible of 10-week-old Sprague–Dawley (SD) rats as bone graft substitutes. Micro-computed tomography (Micro-CT) and immunohistochemical staining for the osteogenesis biomarkers, Runx2, osteocalcin, and the leptin receptor, were performed to investigate and compare bone regeneration between the groups. Although the micro-CT results showed the highest bone mineral density (BMD) and bone volume to total volume (BV/TV) with β-TCP, immunohistochemical analysis indicated better osteogenesis-promoting ability of β-TCP/PDLLA, especially at an early stage of the bone healing process. These results confirmed that the novel nano-biocomposite, β-TCP/PDLLA, which has excellent biocompatibility, bioresorbability and bioactive/osteoconductivity, has the potential to become a next-generation biomaterial for use as a bone graft substitute in maxillofacial reconstructive surgery.

Dimensional changes of the maxillary sinus augmented with a collagenated synthetic bone block or synthetic bone particulates: A pre-clinical study in rabbits

OBJECTIVE

To compare the efficacy of a collagenated synthetic bone substitute (C-SBS) to a particulated synthetic bone substitute (P-SBS) in volume maintenance and new bone formations in a rabbit sinus model.

MATERIALS AND METHODS

Either C-SBS or P-SBS was grafted in both sinuses of 16 rabbits. Four (N = 8) or 12 (N = 8) weeks after the surgery, total augmented volume (TAV) and area (TAA), as well as new bone volume (NBV) and area (NBA), were statistically compared by radiographic and histomorphometric analyses (p < .05).

RESULTS

The differences in TAV, NBV, TAA and NBA between C-SBS and P-SBS groups at 4 weeks were not statistically significant. The TAV (267.13 ± 62.08 vs. 200.18 ± 40.32 mm³ ) and NBV (103.26 ± 10.50 vs. 71.10 ± 7.58 mm³ ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05). The TAA (19.36 ± 2.88 vs. 14.48 ± 2.08 mm² ) and NBA (5.43 ± 1.20 vs. 3.76 ± 0.78 mm² ) in group C-SBS were significantly higher than in group P-SBS at 12 weeks (p < .05).

CONCLUSIONS

Collagenated synthetic bone substitute grafted in rabbit sinuses demonstrated more favourable outcomes across all outcome measures compared to P-SBS at 12 weeks.

Effect of Simvastatin on Bone Regeneration: A Histologic and Histomorphometric Analysis

PURPOSE

The purpose of the present study was to evaluate the efficacy of simvastatin administration as an osteoinductive agent combined with bovine bone material (BBM) for augmentation of human maxillary sinuses.

MATERIALS AND METHODS

In the present randomized clinical trial with a split-mouth design, 24 maxillary sinuses in 12 patients were augmented using BBM alone or BBM combined with simvastatin. Biopsy samples were taken 9 months after maxillary sinus floor augmentation for histologic and histomorphometric analyses. A total of 44 implants were placed in the augmented bone.

RESULTS

The results of the microscopic assessment of most samples revealed no inflammation or only mild chronic inflammation. Lamellation was detectable in old bone trabeculae under polarized light microscopy but was not observed in newly formed bone. Osteocytes were found with a lower frequency in the lacunae of newly formed bone compared with normal bone. No significant differences were found in the amount of newly formed bone and the amount of residual particles between the 2 groups.

CONCLUSIONS

Despite the greater mean percentage of newly formed bone in the test group, the histomorphometric analysis results did not show a significant positive effect for the use of simvastatin in maxillary sinus augmentation.

Combining autologous particulate dentin, L-PRF, and fibrinogen to create a matrix for predictable ridge preservation: a pilot clinical study

OBJECTIVES

The aim of this study was to describe the histological and clinical outcome of "dentin block" (a mixture of autologous particulate dentin, leukocyte- and platelet-rich fibrin (L-PRF), and liquid fibrinogen) in alveolar ridge preservation.

MATERIAL AND METHODS

Ten extraction sockets were grafted with "dentin block," a mixture of particulate autologous dentin with chopped leukocyte-platelet-rich fibrin (L-PRF) membranes at a 1:1 ratio, and liquid fibrinogen as a binder. Two grafted sites were followed at 4 and 5 months, and 6 sites at 6 months. Biopsies were taken from the core of the grafted site for histologic and histo-morphometric analysis.

RESULTS

All patients completed the study without any adverse event. The vertical and horizontal dimensions of the alveolar ridge were preserved or even increased after 4, 5, or 6 months and remained stable after 6 months of the implant placement. The histological examination revealed a median relative percentage of bone, dentin, and connective tissue of 57.0, 0.9, and 39.3%, respectively. A comparison of samples at different time points (4, 5, and 6 months) showed a progressive increase in the proportion of bone with a decrease in the proportion of dentin. The bone was compact with normal osteocytes and moderate osteoblastic activity. In 4 out of 10 samples, no dentin was observed; in the other samples, it represented 1-5% (with geometric fragments).

CONCLUSIONS

Dentin block showed to be a suitable bone substitute in an alveolar ridges preservation model.

CLINICAL RELEVANCE

The promising results of dentin block as a bone substitute in alveolar ridge preservation could have an important clinical impact considering this biomaterial brings together the regenerative potential of three autologous products with excellent biological and clinical behavior, low risk of adverse effects, and feasible acquisition.

Premaxilla: up to which age it remains separated from the maxilla by a suture, how often it occurs in children and adults, and possible clinical and therapeutic implications: Study of 1,138 human skulls

Objective:

To evaluate topographic and temporal aspects of premaxillary bone and premaxillary-maxillary suture, since they are fundamental anatomical elements little explored clinically.

Methods:

1,138 human dry skulls were evaluated, of which 116 (10.19%) of the specimens were children, and 1,022 (89.81%) were adults. The skulls were photographed and the percentage of premaxillary-maxillary suture opening was determined. Subsequently the data were tabulated and submitted to statistical analysis, adopting a level of significance of 5%.

Results:

The progression of premaxillary suture closure from birth to 12 years of age was 3.72% per year. In 100% of the skulls up to 12 years, the premaxillary-maxillary suture open in the palatal region was observed, while 6.16% of adults presented different degrees of opening.

Conclusions:

The premaxilla exists in an independent way within the maxillary complex and the presence of the premaxilla-maxillary suture justifies the success of anteroposterior expansions to stimulate the growth of the middle third of the face, solving anatomical and functional problems.

The bone regeneration capacity of 3D-printed templates in calvarial defect models: A systematic review and meta-analysis

3D-printed templates are being used for bone tissue regeneration (BTR) as temporary guides. In the current review, we analyze the factors considered in producing potentially bioresorbable/degradable 3D-printed templates and their influence on BTR in calvarial bone defect (CBD) animal models. In addition, a meta-analysis was done to compare the achieved BTR for each type of template material (polymer, ceramic or composites). Database collection was completed by January 2018, and the inclusion criteria were all titles and keywords combining 3D printing and BTR in CBD models. Clinical trials and poorly-documented in vivo studies were excluded from this study. A total of 45 relevant studies were finally included and reviewed, and an additional check list was followed before inclusion in the meta-analysis, where material type, porosity %, and the regenerated bone area were collected and analyzed statistically. Overall, the capacity of the printed templates to support BTR was found to depend in large part on the amount of available space (porosity %) provided by the printed templates. Printed ceramic and composite templates showed the best BTR capacity, and the optimum printed template structure was found to have total porosity >50% with a pore diameter between 300 and 400 µm. Additional features and engineered macro-channels within the printed templates increased BTR capacity at long time points (12 weeks). Although the size of bone defects in rabbits was larger than in rats, BTR was greater in rabbits (almost double) at all time points and for all materials used. STATEMENT OF SIGNIFICANCE: In the present study, we reviewed the factors considered in producing degradable 3D-printed templates and their influence on bone tissue regeneration (BTR) in calvarial bone defects through the last 15 years. A meta-analysis was applied on the collected data to quantify and analyze BTR related to each type of template material. The concluded data states the importance of 3D-printed templates for BTR and indicates the ideal design required for an effective clinical translation. The evidence-based guidelines for the best BTR capacity endorse the use of printed composite and ceramic templates with total porosity >50%, pore diameter between 300 and 400 µm, and added engineered macro-channels within the printed templates.

Radiographic and histologic effects of bone morphogenetic protein-2/hydroxyapatite within bioabsorbable magnesium screws in a rabbit model

Background

Hydrogen gas formed by magnesium (Mg) screw corrosion can accumulate around the implant and create bone cysts, long-term osteolysis lesions, and bone healing delay. Thus, several authors currently do not recommend Mg implants for clinical use. In contrast, bone morphogenetic proteins (BMP)-2 have a very strong osteoinductive activity. The purpose of this study was to evaluate the effect of rhBMP-2/hydroxyapatite (HA) inside specially designed Mg cannulated screws in a rabbit femur model for hydrogen gas formation avoidance.

Methods

Fifteen rabbits underwent randomly different cannulated Mg screw implantation in both distal femora; 30 femora were divided into three groups depending on the materials fill in the cannulated Mg screw: control group (Mg screw with no treatment), HA group (Mg screw with HA), and BMP-2/HA group (Mg screw with a composite BMP-2/HA). Plain radiography, micro-CT, and histological analysis were accomplished, and the ability to release BMP-2 of the screws was evaluated by immersion of both the screw with no treatment and screw with a composite BMP-2/HA into the SBF for up to 7 days.

Results

X-ray assessment found the gas shadow around the implant was slightly smaller in the BMP-2/HA group than the HA and control groups at 8 weeks. Micro-CT analysis demonstrated statistically significant higher new bone formation in the BMP-2/HA group than the other groups, respectively, which also correlated with a decreased gas volume. Histological analysis showed higher osteointegration between implants and host femurs in the BMP-2/HA group than the HA and control groups at 12 weeks.

Conclusions

This study indicates that the combination of BMP-2/HA within Mg screws enhances new bone formation and therefore has the potential to decrease the complications of hydrogen gas formation around these implants.

Carbon Fiber Reinforced PEEK Composites Based on 3D-Printing Technology for Orthopedic and Dental Applications

Fused deposition modeling (FDM) is a rapidly growing three-dimensional (3D) printing technology and has great potential in medicine. Polyether-ether-ketone (PEEK) is a biocompatible high-performance polymer, which is suitable to be used as an orthopedic/dental implant material. However, the mechanical properties and biocompatibility of FDM-printed PEEK and its composites are still not clear. In this study, FDM-printed pure PEEK and carbon fiber reinforced PEEK (CFR-PEEK) composite were successfully fabricated by FDM and characterized by mechanical tests. Moreover, the sample surfaces were modified with polishing and sandblasting methods to analyze the influence of surface roughness and topography on general biocompatibility (cytotoxicity) and cell adhesion. The results indicated that the printed CFR-PEEK samples had significantly higher general mechanical strengths than the printed pure PEEK (even though there was no statistical difference in compressive strength). Both PEEK and CFR-PEEK materials showed good biocompatibility with and without surface modification. Cell densities on the "as-printed" PEEK and the CFR-PEEK sample surfaces were significantly higher than on the corresponding polished and sandblasted samples. Therefore, the FDM-printed CFR-PEEK composite with proper mechanical strengths has potential as a biomaterial for bone grafting and tissue engineering applications.

Evaluation of L-PRF combined with deproteinized bovine bone mineral for early implant placement after maxillary sinus augmentation: A randomized clinical trial

PURPOSE

To investigate the effectiveness of adding leukocyte and platelet-rich fibrin (L-PRF) to deproteinized bovine bone mineral (DBBM) for early implant placement after maxillary sinus augmentation.

MATERIALS AND METHODS

Twelve patients requiring two-stage bilateral maxillary sinus augmentation were enrolled to the study. The elevated sinus cavities were randomly grafted with DBBM + L-PRF (test) or DBBM alone (control) in a split-mouth design. Implants were placed in the augmented sites after 4 months in the test group and 8 months in the control group. Bone biopsies were collected during implant placement for histomorphometric evaluation. Resonance frequency analysis was performed immediately after implant placement and at implant loading in both groups. Cone-beam computed tomography was obtained preoperatively and postoperatively for evaluation of graft volume changes.

RESULTS

Both procedures were effective for maxillary sinus augmentation. Cone-beam computed tomography analysis did not reveal differences in graft volume between test and control group at any of the evaluated time points (P > .05). Histological evaluation demonstrated increased percentage of newly formed bone for the test group (44.58% ± 13.9%) compared to the control group (30.02% ± 8.42%; P = .0087). The amount of residual graft in the control group was significantly higher (13.75% ± 9.99%) than in the test group (3.59 ± 4.22; P = .0111). Implant stability quotient (ISQ) immediately after implant placement was significantly higher in the control group (75.13 ± 5.69) compared to the test group (60.9 ± 9.35; P = .0003). The ISQ values at loading did not differ between the groups (P = .8587). Implant survival rate was 100% for both groups.

CONCLUSION

The addition of L-PRF to the DBBM into the maxillary sinus allowed early implant placement (4 months) with increased new bone formation than DBBM alone after 8 months of healing.

Histologic and Histomorphometric Analysis of Bone Regeneration with Bovine Grafting Material after 24 Months of Healing. A Case Report

Anorganic bovine bone mineral matrix (ABBMM) has been reported to have osteoconductive properties and no inflammatory or adverse responses when used as grafting material in sinus augmentation procedures. However, controversy remains in regard to degradation rate of ABBMM. The aim of this study was to histologically and histomorphometrically evaluate the degradation of ABBMM in human bone samples obtained in one patient 24 months after sinus augmentation. Materials and Methods: The histologic and histomorphometric analysis was performed by means of light microscopy in three specimens harvested from the same patient, Results: After 24 months the tissue pattern appeared to be composed of residual particles, some in close contact with the newly formed bone, others separated by translucent areas and osteoid tissues. Newly-formed bone presented different levels of maturation and numerous osteocytes, with greater numbers in bone closer to the grafted particles (27.3% vs. 11.2%, p < 0.05). The histomorphometric analysis showed mean values of 40.84% newly-formed bone, 33.58% residual graft material, 23.84% marrow spaces, and 1.69% osteoid tissue, Conclusions: Even though ABBMM underwent considerable resorption, a great amount of residual grafting material was still present after two years of healing following sinus augmentation. This study confirms that the bovine grafts can be classified as long-term degradation materials.

Bone augmentation using autogenous bone versus biomaterial in the posterior region of atrophic mandibles: A systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis aimed to answer the PICO question: "Do patients who have received bone grafts with bone substitute (biomaterials) present bone gain (before implant installation), complications, and implant survival rates similar to autogenous grafts when used in the posterior mandible region?".

DATA

This review followed the PRISMA statement and has been registered at PROSPERO (CRD42016048471). Studies published in English, randomized controlled and/or prospective clinical trials with at least 10 patients, and studies that compared grafts with bone substitutes to autogenous bone grafts (split-mouth design) were included.

SOURCES

An electronic search and a manual search were conducted in PubMed/MEDLINE, Scopus, and Cochrane databases up to April 2018.

STUDY SELECTION

Our initial search yielded 640 articles; we selected four articles that met the inclusion criteria. All selected studies used a split-mouth design.

RESULTS

Our analysis revealed no significant difference between the biomaterial and autogenous groups in terms of bone gain (P = 0.11; mean difference [MD]: 0.59; 95% confidence interval [CI]: -0.13-1.31) or complication rate (P = 0.72; risk ratio [RR]: 1.25; 95% CI: 0.37-4.23). Sixty-six implants were installed in the biomaterial group and 63 in the autogenous group; these showed no significant difference in implant survival rate (P = 0.50; RR: 1.57; 95% CI: 0.43-5.81).

CONCLUSION

We conclude that biomaterials or autogenous bone are indicated for the reconstruction of the posterior mandibular atrophic region, without lowering implant survival.

Premaxilla: an independent bone that can base therapeutics for middle third growth!

Premaxilla, in its early descriptions, had the participation of Goethe. In our face, in a certain period of growth and development processes, premaxilla is an independent and, then, a semi-independent bone to finally be totally integrated to the maxilla. Formation of the premaxilla acts as a stabilization element inside the facial skeleton comparable to the cornerstone of a Roman arch and is closely related to the development of human face and its abnormal growth with characteristic malformations. Until when the premaxillary-maxillary suture remains open and offers opportunities to orthopedically influence facial growth to exert influence over facial esthetics and function? Contact with preliminary results in 1183 skulls from anatomic museums at USP, Unicamp and Unifesp led us to question therapeutic perspectives and its clinical applicability.

Maxillary Sinus Augmentation for Dental Implant Rehabilitation of the Edentulous Ridge: A Comprehensive Overview of Systematic Reviews

OBJECTIVES

The objective of this systemic review was to perform a comprehensive overview of systematic reviews and meta-analyses of the maxillary sinus augmentation procedure for implant rehabilitation in humans. The following were evaluated in this overview: (1) anatomic variables affecting sinus augmentation, (2) histomorphometric analysis of the grafted sinus, (3) volumetric changes after sinus grafting, and (4) implant survival beyond 1 year.

MATERIAL AND METHODS

Electronic databases were searched for systematic reviews and meta-analyses of implant-related sinus augmentation published from 1976 to September 2015. The studies selected must identify itself as a systemic review or meta-analysis in the title or abstract and must pertain to sinus augmentation.

RESULTS

Thirty-three publications fulfilled the review criteria. The AMSTAR ratings for the 33 chosen reviews scored greater than 3 of 11, with 8 reviews scoring greater or equal to 8 of 11.

CONCLUSION

The outcome of this overview suggested that the following will increase the success of sinus augmentation and survival of implants placed in the grafted sinus: (1) the use of barrier membranes over the lateral window when using a lateral approach to graft the sinus, (2) the use of particulate autogenous bone with or without other substitute graft materials, (3) sinus augmentation without the use of grafting materials may be considered provided that the space between the sinus membrane and floor can be maintained, (4) the use of rough-surfaced implants, (5) simultaneous implant placement with residual bone height greater than 4 mm, and (6) the cessation of smoking.

Sinus floor elevation procedures to enable implant placement and integration: techniques, biological aspects and clinical outcomes

Implant treatment in an atrophied edentulous posterior maxilla constitutes a challenge for the therapeutic team. The authors of the present study acknowledge that modern micro-rough surface implants in lengths of about 8-10 mm or longer and of different brands are similarly successful. Consequently, the authors propose that the use of different sinus floor elevation techniques should be considered when < 8 mm of bone is available below the maxillary sinus. The type of sinus floor elevation technique selected is mainly based on residual vertical bone height, marginal bone width, local intrasinus anatomy and the number of teeth to be replaced, although other factors (such as surgical training and surgical experience) may have an impact. It is proposed that a transcrestal sinus floor elevation approach can be considered as a first-choice method for single tooth gaps in situations with sufficient width for implant placement and a residual bone height of 5-8 mm, while lateral sinus floor elevation, with or without grafting materials, is indicated when < 5 mm of bone is available and when several teeth are to be replaced. With regard to time of implant placement, a one-stage procedure is preferred provided that high primary stability can be ensured.

Evaluation of a new biphasic calcium phosphate for maxillary sinus floor elevation: Micro-CT and histomorphometrical analyses

Objectives

Synthetic biphasic calcium phosphate (BCP) with a hydroxyapatite/ß‐tricalcium phosphate (HA/ß‐TCP) ratio of 60/40 (BCP60/40) is successfully used as alternative for autologous bone in patients undergoing maxillary sinus floor elevation (MSFE) for dental implant placement. A high percentage of HA in BCP60/40 may hamper efficient scaffold remodeling. Osteogenesis and neovascularization are pivotal in effective bone regeneration. We aimed to investigate whether differences exist in osteogenic and/or vasculogenic potential of BCP60/40 and BCP20/80 in patients undergoing MSFE.

Materials and methods

Twenty patients undergoing MSFE were treated with BCP60/40 (n = 10) or BCP20/80 (n = 10). Bone and graft volumes were determined by micro‐computed tomography and histomorphometrical analysis of biopsies of the augmented region. Osteoid volumes, number of osteoclasts, and blood vessels were determined by histomorphometrical analysis. The biopsies were taken 6.5 months (26 weeks) postoperatively prior to dental implant placement.

Results

Bone and osteoid volumes were 9.7% and 0.8% higher at the most cranial side of the BCP20/80 biopsies compared to the BCP60/40 biopsies. Graft volumes, number of osteoclasts, and blood vessels were similar in both groups.

Conclusions

BCP20/80 showed enhanced osteogenic potential in patients undergoing MSFE compared to BCP60/40, due to either a faster bone remodeling rate or an earlier start of bone formation in BCP20/80‐treated patients, suggesting that a higher TCP content positively contributes to the bone remodeling rate. Therefore, BCP20/80 might perform better, at least in the short term, as a scaffold for bone augmentation in the MSFE model than BCP60/40 as more bone is formed, and more osteoid is deposited at the cranial side in BCP20/80‐treated patients compared to BCP60/40‐treated patients. However, catch‐up of BCP60/40 in the long term cannot be ruled out.

Dental pulp stem cells for bone tissue engineering: a review of the current literature and a look to the future

The aim of this narrative review is to investigate the implication of mesenchymal stem cells harvested from human dental pulp in in vivo bone tissue regeneration. We focused on studies related to roles of human dental pulp stem cells in in vivo bone regeneration. A total of 1021 studies were identified; after the assessment of eligibility, only 39 studies were included in the review. The evaluated information of the studies regards the experimental strategies (e.g., the isolation method, the scaffold, the in vivo animal models). The overall main evidences highlighted from the analysis are that dental pulp stem cells and human-exfoliated deciduous teeth stem cells supported by a suitable scaffold should be considered a valuable source for bone tissue regeneration.

A new synthetic granular calcium phosphate compound induces new bone in a sinus lift rabbit model

OBJECTIVES

The aim of this study was to investigate if a synthetic granular calcium phosphate compound (CPC) and a composite bisphosphonate-linked hyaluronic acid-calcium phosphate hydrogel (HABP·CaP) induced similar or more amount of bone as bovine mineral in a modified sinus lift rabbit model.

MATERIAL AND METHODS

Eighteen adult male New Zeeland White rabbits, received randomly one of the two test materials on a random side of the face, and bovine mineral as control on the contralateral side. In a sinus lift, the sinus mucosa was elevated and a titanium mini-implant was placed in the alveolar bone. Augmentation material (CPC, HABP·CaP or bovine bone) was applied in the space around the implant. The rabbits were euthanized three months after surgery and qualitative and histomorphometric evaluation were conducted. Histomorphometric evaluation included three different regions of interest (ROIs) and the bone to implant contact on each installed implant.

RESULTS

Qualitative assessment (p = <.05), histomorphometric evaluations (p = < .01), and implant incorporation (p = <.05) showed that CPC and bovine mineral induced similar amount of bone and more than the HABP·CaP hydrogel.

CONCLUSION

CPC induced similar amount of bone as bovine mineral and both materials induced more bone than HABP·CaP hydrogel.

CLINICAL SIGNIFICANCE

The CPC is suggested as a synthetic alternative for augmentations in the maxillofacial area.

Dental pulp stem cells for bone tissue engineering: a review of the current literature and a look to the future

The aim of this narrative review is to investigate the implication of mesenchymal stem cells harvested from human dental pulp in in vivo bone tissue regeneration. We focused on studies related to roles of human dental pulp stem cells in in vivo bone regeneration. A total of 1021 studies were identified; after the assessment of eligibility, only 39 studies were included in the review. The evaluated information of the studies regards the experimental strategies (e.g., the isolation method, the scaffold, the in vivo animal models). The overall main evidences highlighted from the analysis are that dental pulp stem cells and human-exfoliated deciduous teeth stem cells supported by a suitable scaffold should be considered a valuable source for bone tissue regeneration.