Maxillary Sinus Grafting With Biphasic Bone Ceramic or Autogenous Bone: Clinical, Histologic, and Histomorphometric Results From a Randomized Controlled Clinical Trial

Comparative Insights into Bone Substitutes for Two-Stage Maxillary Sinus Floor Elevation: A Bayesian Network Approach

To investigate the histomorphometric performance of two-stage maxillary sinus floor elevation (TMSFE) with various bone substitutes in the treatment of atrophic posterior maxilla. Four databases (PubMed, Embase, Web of Science, and The Cochrane Library) were searched from the beginning of database establishment to August 8, 2023. The included articles were limited to the English language. A systematic search was performed to identify randomized controlled trials assessing the histological performance of various biomaterials in TMSFE with a follow-up of 5-8 months. The main outcome was an area of new bone, and an additional outcome was residual graft material. Extracted data were analyzed by using a Bayesian approach (the Markov chain Monte Carlo) to establish ranks of various biomaterials in R language. Finally, the search identified 22 studies that reported 22 trials on bone area (17 kinds of biomaterials) and 12 studies on residual graft materials (12 kinds of biomaterials) after the exclusion of one study disconnected from the network plot. No local inconsistency could be found in studies regarding bone formation, while no closed loop was detected in residual graft material. The top 3 probabilities of biomaterials in terms of bone formation were Allograft + Xenograft (AG + X) (87.14%), X + Polymer (75.69%), and Autogenous Bone + Bioactive Glass (AB + BG) (71.44%). AG + X had the highest probability (87.14%) of being the most optimal treatment for bone formation. Biphasic calcium phosphate + Fibrin sealant (BCP + FS) was ranked as the slowest absorbing biomaterial (78.27%) in TMSFE. Within the limitations of the current network meta-analysis, AG + X may represent an optimal biomaterial for bone formation in TMSFE. The use of X in combination with other biomaterials demonstrates superior osteogenic effects in TMSFE. BCP + FS exhibited strong mechanical properties during a short-term observational period. The present findings suggest that AB is not the only feasible standard for bone grafts.

Additive Manufacturing Titanium Dental Implants Placed in Sinuses Grafted with 70HA:30-TCP: A One-Year Retrospective Study for Evaluation of Survival Rate

The present short-term retrospective study evaluated the implant survival rate and peri-implant bone loss around additive-manufactured titanium implants placed in sinuses grafted with Plenum Osshp (Plenum Bioengenharia, Jundia, SP, Brazil) (70HA:30β-TCP) material. A total of 39 implants were inserted after 23 sinus floor elevation procedures in 16 consecutive patients. Prosthetic rehabilitation included fixed partial prostheses (three units), single crowns (eleven units), and fixed full arches (three units). Clinical and radiographic parameters of implant-supported restorations were evaluated after at least one year of occlusal loading. The implant-crown success criteria included the absence of pain, suppuration, and clinical mobility, an average distance between the implant shoulder and the first visible bone contact (DIB) < 1.0 mm from the initial surgery, and the absence of prosthetic complications at the implant-abutment interface. The overall cumulative implant survival rate was 97.43%. No prosthetic complications at the implant-abutment interface were reported. After one year, the mean DIB was 0.23 mm ± 0.14. Within the limits of this retrospective study, it can be concluded that 70 HA:30 β-TCP allowed stable and reliable bone support to maintain healthy conditions around titanium dental implants produced by additive manufacturing.

Exploring the potential of calcium-based biomaterials for bone regeneration in dentistry: a systematic review

INTRODUCTION

Regenerative medicine emerged as a promising strategy for addressing bone defects, with several bone grafts currently being used, including autografts, allografts, xenografts and alloplasts. Calcium-based biomaterials (CaXs), a well-known class of synthetic materials, have demonstrated good biological properties and are being investigated for their potential to facilitate bone regeneration. This systematic review evaluates the current clinical applications of CaXs in dentistry for bone regeneration.

EVIDENCE ACQUISITION

A comprehensive search was conducted to collect information about CaXs and their applications in the dental field over the last ten years. The search was limited to relevant articles published in peer-reviewed journals.

EVIDENCE SYNTHESIS

A total of 72 articles were included in this scoping review, with eight studies related to periodontology, 63 in implantology and three in maxillofacial surgery respectively. The findings suggest that CaXs hold promise as an alternative intervention for minor bone regeneration in dentistry.

CONCLUSIONS

Calcium-based biomaterials have shown potential as a viable option for bone regeneration in dentistry. Further research is warranted to fully understand their efficacy and safety in larger bone defects. CaXs represent an exciting avenue for researchers and clinicians to explore in their ongoing efforts to advance regenerative medicine.

Prospective Clinical Study with New Materials for Tissue Regeneration: A Study in Humans

OBJECTIVE

 This study was performed to evaluate the clinical, radiographic, and histomorphometric outcomes of novel bone grafting materials and dental membranes and to compare the results with current data from the literature.

MATERIALS AND METHODS

 New synthetic bone substitutes, consisting of biphasic calcium phosphate in the ratio of 60% hydroxyapatite and 40% β-tricalcium phosphate, were applied in bony defects and covered by either a novel synthetic poly(lactic-co-glycolic) acid (PLGA) or porcine collagen membrane. A sample of 51 biomaterials was placed in a total of 20 patients during different surgical protocols. Implants were simultaneously inserted, and in the case of sinus floor elevations 6 months later. Pre- and postoperative cone-beam computed tomographies were taken. Bone biopsies were harvested from augmented sides and processed for histomorphometric evaluation.

STATISTICAL ANALYSIS

 Averages and ranges were calculated for the percentage of newly formed bone, residual biomaterial, and connective tissue. Data were submitted to analyze the radiological mean differences in length, width, and density. Paired t-tests were deployed for the analysis of differences within each group between the baseline (preoperative) and the final (postoperative) measurements.

RESULTS

 The mean bone gain in length and width were 0.96 ± 3.33 mm (+27.59%) and 1.22 ± 1.87 mm (+30.48%), respectively. The bone density was increased by a factor of 4, reaching an average of 387.47 ± 328.86 HU. Histomorphometric evaluations revealed new bone formation of 41.44 ± 5.37%, residual biomaterial of 24.91 ± 7.31%, and connective tissue of 33.64 ± 4.81%. The mean healing period was 8.32 ± 3.00 months.

CONCLUSIONS

 Data from this study confirmed the suitability of the tested materials in dental surgery. The biomaterials may be recommended for various clinical procedures. A satisfactory level of increase of new bone was reported in augmented sides. No significant differences were observed between the tested membranes. PLGA membranes might be superior to collagen membranes for their easier handling.

From Synthesis to Clinical Trial: Novel Bioinductive Calcium Deficient HA/β-TCP Bone Grafting Nanomaterial

Maxillary sinus augmentation is a commonly used procedure for the placement of dental implants. However, the use of natural and synthetic materials in this procedure has resulted in postoperative complications ranging from 12% to 38%. To address this issue, we developed a novel calcium deficient HA/β-TCP bone grafting nanomaterial using a two-step synthesis method with appropriate structural and chemical parameters for sinus lifting applications. We demonstrated that our nanomaterial exhibits high biocompatibility, enhances cell proliferation, and stimulates collagen expression. Furthermore, the degradation of β-TCP in our nanomaterial promotes blood clot formation, which supports cell aggregation and new bone growth. In a clinical trial involving eight cases, we observed the formation of compact bone tissue 8 months after the operation, allowing for the successful installation of dental implants without any early postoperative complications. Our results suggest that our novel bone grafting nanomaterial has the potential to improve the success rate of maxillary sinus augmentation procedures.

Residual Bone Height and New Bone Formation after Maxillary Sinus Augmentation Procedure Using Biomaterials: A Network Meta-Analysis of Clinical Trials

BACKGROUND

Different factors may affect new bone formation following maxillary sinus floor augmentation for the rehabilitation of posterior edentulous maxilla. The purpose of this study was to determine the influence of residual bone height (RBH) on new bone formation after lateral sinus augmentation utilizing different biomaterials, through a network meta-analysis (NMA).

METHODS

PUBMED, Scopus, and Web of Science electronic databases were searched until 31 December 2022 to obtain relevant articles. A hand search was also conducted. Randomised controlled studies on maxillary sinus augmentation comparing different grafting materials in patients with atrophic posterior maxilla, in need of prosthetic rehabilitation, were included. The risk of bias was assessed following the guidelines of the Cochrane Collaboration. The primary outcome was new bone formation (NBF), assessed histomorphometrically. The statistical analysis was performed by splitting the data according to RBH (<4 mm and ≥4 mm).

RESULTS

A total of 67 studies were eligible for conducting NMA. Overall, in the included studies, 1955 patients were treated and 2405 sinus augmentation procedures were performed. The biomaterials used were grouped into: autogenous bone (Auto), xenografts (XG), allografts (AG), alloplasts (AP), bioactive agents (Bio), hyaluronic acid (HA), and combinations of these. An inconsistency factor (IF) seen in the entire loop of the XG, AP, and Bio+AP was found to be statistically significant. The highest-ranked biomaterials for the <4 mm RBH outcome were XG+AG, XG+AP, and Auto. Similarly, the surface under the cumulative ranking curve (SUCRA) of biomaterials for ≥4 mm RBH was Auto, Bio+XG, and XG+Auto.

CONCLUSION

There is no grafting biomaterial that is consistently performing better than others. The performance of the materials in terms of NBF may depend on the RBH. While choosing a biomaterial, practitioners should consider both patient-specific aspects and sinus clinical characteristics.

Bone vitality and vascularization of mandibular and maxillary bone grafts in maxillary sinus floor elevation: A retrospective cohort study

OBJECTIVES

Mandibular retromolar (predominantly cortical) and maxillary tuberosity (predominantly cancellous) bone grafts are used in patients undergoing maxillary sinus floor elevation (MSFE) for dental implant placement. The aim of this retrospective cohort study was to investigate whether differences exist in bone formation and vascularization after grafting with either bone source in patients undergoing MSFE.

METHODS

Fifteen patients undergoing MSFE were treated with retromolar (n = 9) or tuberosity (n = 6) bone grafts. Biopsies were taken 4 months postoperatively prior to dental implant placement, and histomorphometrically analyzed to quantify bone and osteoid area, number of total, apoptotic, and receptor activator of nuclear factor-κB ligand (RANKL)-positive osteocytes, small and large-sized blood vessels, and osteoclasts. The grafted area was divided in three regions (caudal-cranial): RI, RII, and RIII.

RESULTS

Bone volume was 40% (RII, RIII) higher and osteoid volume 10% (RII) lower in retromolar compared to tuberosity-grafted areas. Total osteocyte number and number of RANKL-positive osteocytes were 23% (RII) and 90% (RI, RII) lower, but osteoclast number was higher (retromolar: 12, tuberosity: 0) in retromolar-grafted areas. The total number of blood vessels was 80% (RI) to 60% (RIII) lower, while the percentage of large-sized blood vessels was 86% (RI) to 25% (RIII) higher in retromolar-grafted areas. Number of osteocyte lacunae and apoptotic osteocytes were similar in both bone grafts used.

CONCLUSIONS

Compared to the retromolar bone, tuberosity bone showed increased bone vitality and vascularization in patients undergoing MSFE, likely due to faster bone remodeling or earlier start of new bone formation. Therefore, tuberosity bone grafts might perform better in enhancing bone regeneration.

Comparison of osseointegration in areas grafted with deproteinized bovine bone and native bone. A preclinical study

The aim of this study was to evaluate the osseointegration of implants placed in rat tibia sites grafted with Deproteinized Bovine Bone (DBB) and Native Bone (NB). Twenty-eight rats were divided into two groups according to the type of substrate in which the implants were to be placed: NB - implants placed in native bone; DBB - implants placed in areas grafted with DBB. In the DBB group, the bone defect was made and filled with the bone substitute 60 days before placing the implant. The animals were euthanized 15 or 45 days after implant placement. Osseointegration was assessed by the removal torque, volume of mineralized tissues around the implants (BV/TV), bone-implant contact (%BIC), and bone between threads (%BBT). The implants placed in NB presented higher removal torque (8.00 ± 1.26 Ncm vs. 2.33 ± 0.41 Ncm at 15 days and 22.00 ± 2.44 Ncm vs. 4.00 ± 1.41 Ncm at 45 days), higher %BV/TV (47.92 ± 1.54% vs. 33.33 ± 4.77% at 15 days and 70.06 ± 0.91% vs. 39.89±5.90%at 45 days), higher %BIC (39.68 ± 5.02% vs. 9.12 ± 5.56% at 15 days and 83.23 ± 4.42% vs. 18.81 ± 7.21% at 45 days), and higher %BBT (34.33 ± 5.42% vs. 13.24 ± 8.72% at 15 days and 82.33 ± 3.13% vs. 22.26 ± 8.27% at 45 days) than the implants placed in DBB grafted areas. The degree of osseointegration was lower in implants placed in the area grafted with DBB than in NB in rat tibias.

Comparison of the osseointegration of implants placed in areas grafted with HA/TCP and native bone

This study evaluated the osseointegration of implants in areas grafted with biphasic ceramic based on hydroxyapatite/β-tricalcium phosphate (HA/TCP) and in native bone (NB). Twenty-eight rats were randomly assigned into two groups of 14 animals each: HA/TCP group: implants installed in areas grafted with HA/TCP and NB group: implants installed in areas of native bone. Bone defects were made in both tibiae of the rats belonging to the HA/TCP group and then filled with this bone substitute. After 60 days, the rats were submitted to surgical procedures for implant placement in grafted areas in both tibiae in the HA/TCP group while the implants were installed directly in native bone in the NB group. The animals were euthanized 15 and 45 days, respectively, after the implant placement. Biomechanical (removal torque), microtomographic (volume of mineralized tissues around the implants), and histomorphometric (Bone-Implant contact-%BIC and bone area between the implant threads-%BBT) analyzes were conducted to assess the osseointegration process. The HA/TCP group showed lower values of removal torque, volume of mineralized tissue around the implants, lower %BIC, and %BBT compared to the NB group in both experimental periods. Osseointegration of implants placed in grafted areas with HA/TCP was lower compared to the osseointegration observed in native bone areas.

Magnesium Modified β-Tricalcium Phosphate Induces Cell Osteogenic Differentiation In Vitro and Bone Regeneration In Vivo

In vitro, in vivo, and clinical studies have shown how the physicochemical and biological properties of β-tricalcium phosphate (β-TCP) work in bone regeneration. This study aimed to improve the properties of β-TCP by achieving optimum surface and bulk β-TCP chemical/physical properties through the hydrothermal addition of magnesium (Mg) and to later establish the biocompatibility of β-TCP/Mg for bone grafting and tissue engineering treatments. Multiple in vitro and in vivo analyses were used to complete β-TCP/Mg physicochemical and biological characterization. The addition of MgO brought about a modest rise in the number of β-TCP surface particles, indicating improvements in alkaline phosphatase (ALP) activity on day 21 (p < 0.05) and in the WST-1assay on all days (p < 0.05), with a corresponding increase in the upregulation of ALP and bone sialoprotein. SEM analyses stated that the surfaces of the β-TCP particles were not altered after the addition of Mg. Micro-CT and histomorphometric analysis from rabbit calvaria critical defects resulted in β-TCP/Mg managing to reform more new bone than the control defects and β-TCP control at 2, 6, and 8 weeks (* p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001, and **** p ≤ 0.0001). The hydrothermal addition of MgO to the β-TCP surfaces ameliorated its biocompatibility without altering its surface roughness resulting from the elemental composition while enhancing cell viability and proliferation, inducing more bone regeneration by osteoconduction in vivo and osteoblastic differentiation in vitro.

Comparison of osseointegration in areas grafted with different osteoconductive biomaterials. Preclinical study

Abstract This study evaluated osseointegration in areas grafted with deproteinized bovine bone (DBB) and biphasic ceramic based on hydroxyapatite and beta-tricalcium phosphate (HA/TCP) in rat tibias. Noncritical bone defects were made in the tibias of 28 rats that were randomly assigned to 2 groups: DBB: DBB-filled defects and HA/TCP: HA/TCP-filled defects. Bone defects were made in the tibias bilaterally and filled with biomaterials. After 60 days, the implants were inserted, and the animals were euthanized 15 and 45 days after the implants were installed. Osseointegration was evaluated by biomechanical, microtomographic and histometric analysis. Implants installed in the defects filled with DBB presented higher removal torque forces (2.33 ± 0.51 Ncm vs. 1.50 ± 0.54 Ncm) and mineralized tissue volume around implants at 15 days (34.96 ± 3.68 % vs. 25.61 ± 2.95 %) and greater bone-implant contact (20.87 ± 8.28 % vs. 11.52 ± 7.42 %) and bone area within implant threads (26.83 ± 12.35 % vs. 11.98 ± 7.56 %) at 45 days compared to the measurements of implants in areas grafted with HA/TCP. Implants installed in defects in areas grafted with DBB had a better osseointegration pattern than implants placed in defects in areas grafted with HA/TCP.

Histological Comparison between Biphasic Calcium Phosphate and Deproteinized Bovine Bone on Critical-Size Bone Defects

The limited options for bone repair have led to an extensive research of the field and the development of alloplastic and xenogeneic grafts. The purpose of this study was to evaluate bone repair with two bone substitutes: deproteinized bovine bone (DBB) and biphasic calcium phosphate ceramic (BCP) in critical-size defect. A total of 8-mm defects were made in the parietal bones of rabbits (n=12). The animals were divided into three experimental groups: sham (defect filled with a blood clot), DBB (defect filled with DBB), and BCP (defect filled with BCP). After the experimental periods of 15 and 45 days, the animals were euthanized and submitted to histomorphometric analysis. The total defect area, mineralized tissue area, biomaterial area, and soft tissue area were evaluated. A greater amount of immature bone tissue and biomaterial particles were observed in the BCP group compared to DBB and sham at 45 days (p<0.05). There was no difference in the qualitative pattern of bone deposition between DBB and BCP. However, the sham group did not show osteoid islands along with the defect, presenting a greater amount of collagen fibers as well in relation to the DBB and BCP groups. There was a greater number of inflammatory cells in the DBB at 45 days compared to BCP and sham groups. In conclusion, BCP and DBB are options for optimizing the use of bone grafts for maxillofacial rehabilitation. Bone defects treated with BCP showed greater deposition of bone tissue at 45 days.

Clinical and histological outcomes of maxillary sinus floor augmentation with synthetic bone substitutes for dental implant treatment: A meta-analysis

The objective of the present review was to gather all available human randomized clinical trials comparing the clinical and histological results of synthetic bone substitutes used in maxillary sinus floor augmentation. Authors electronically searched in Pubmed/Medline, Scopus and Cochrane databases to analyse the success of endosseous dental implant, implant failure, peri-implant marginal bone loss, newly formed bone and residual bone graft material.  After the search, ten randomized clinical trials were included. Four studies ranging from low to unclear risk of bias were used for meta-analysis, being able to compare only biphasic calcium phosphate (BCP) and deproteinized bovine bone (DBB). A greater amount of residual graft material (mean difference -MD- 4.80 mm; 95% CI, 9.35 to 0.26; P= 0.040) was found in DBB group. No other statistically significant differences were found between BCP and DBB for the rest of outcomes. Thus, our results suggested that BCP can be considered a suitable alternative to DBB in maxillary sinus floor augmentation due to its clinical and histological results.

Bone regeneration of a polymeric sponge technique-Alloplastic bone substitute materials compared with a commercial synthetic bone material (MBCP+TM technology): A histomorphometric study in porcine skull

Background

Polymeric sponge technique is recommended for developing the desired porosity of Biphasic calcium phosphate (BCP) which may favor bone regeneration.

Purpose

To investigate the healing of BCP with ratio of HA30/β‐TCP70 (HA30) and HA70/β‐TCP30 (HA70) polymeric sponge preparation, compare to commercial BCP (MBCP+TM).

Materials and Methods

Materials were tested X‐ray diffraction (XRD) pattern and scanning electron microscope (SEM) analysis. In eight male pigs, six calvarial defects were created in each subject. The defects were the filled with 1 cc of autogenous bone, MBCP+TM (MBCP), HA30, HA70, and left empty (negative group). The new bone formations, residual material particles and bone‐to‐graft contacts were analyzed at 4, 8, 12 and 16 weeks.

Results

Fabricated BCP showed well‐distributed porosity. At 16 weeks, new bone formations were 45.26% (autogenous), 33.52% (MBCP), 24.34% (HA30), 19.43% (HA70) and 3.37% (negative). Residual material particles were 1.88% (autogenous), 17.58% (MBCP), 26.74% (HA30) and 37.03% (HA70). These values were not significant differences (Bonferroni correction <0.005). Bone‐to‐graft contacts were 73.68% (MBCP), which was significantly higher than 41.68% (HA30) and 14.32% (HA70; Bonferroni correction <0.017).

Conclusions

Polymeric sponge technique offers well‐distributed porosity. The new bone formation and residual material particles were comparable to MBCP+TM, but the bone‐to‐graft contact was lower than MBCP+TM.

Maxillary Sinus Floor Augmentation with Autogenous Bone Graft Alone Compared with Alternate Grafting Materials: a Systematic Review and Meta-Analysis Focusing on Histomorphometric Outcome

Objectives

The objective of present systematic review was to test the hypothesis of no difference in histomorphometric outcome after maxillary sinus floor augmentation with autogenous bone graft alone compared with alternate grafting materials applying the lateral window technique.

Material and Methods

MEDLINE (PubMed), Embase and Cochrane library search in combination with hand-search of relevant journals were conducted. Human studies published in English until the 25^th of March, 2020 were included. Histomorphometric outcomes were evaluated by descriptive statistics and meta-analysis including 95% confidence interval (CI).

Results

Electronic search and hand-searching resulted in 1902 entries. Sixteen randomized controlled trials with unclear risk of bias fulfilled the inclusion criteria. Descriptive statistics showed comparable or improved histomorphometric outcomes with autogenous bone graft. Meta-analysis revealed a mean difference of -7.1% (CI = -11.0 to -3.2) indicating a significant higher amount of bone after maxillary sinus floor augmentation with autogenous bone graft compared with alternate grafting materials. Subgroup analysis demonstrated a non-significantly differences of -3.7% (CI = -10.9 to 3.4), -11.5% (CI = -25.9 to 2.8), 2.2% (CI = -16.9 to 21.3), and -4.6% (CI = -14.4 to 5.2), when autogenous bone graft was compared with allogeneic bone graft, xenograft, composite grafting materials involving xenograft or synthetic biomaterial mixed with autogenous bone graft, respectively.

Conclusions

Maxillary sinus floor augmentation with autogenous bone graft seems to facilitate improved histomorphometric outcomes compared with alternate grafting materials. However, the included studies were characterised by an unclear risk of bias and various methodological confounding factors. Hence, the conclusions drawn from the results of present study should be interpreted with caution.

The vertical course of bone regeneration in maxillary sinus floor augmentations: A histomorphometric analysis of human biopsies

Background

Maxillary sinus floor augmentation (MSFA) is a well‐established and predictable augmentation method in severely resorbed maxillae. However, data on the vertical course of bone graft consolidation within the maxillary sinus are rare. The aim of the present study was to quantify the vertical distribution of new bone formation (nBF) in MSFA and to characterize the vertical gradient of bone graft consolidation.

Methods

Eighty‐five human sinus biopsies were harvested 6 ± 1 months after MSFA. Histological thin‐ground sections were prepared and histomorphometrically analyzed. The volume of newly formed bone (nBV/TV) was measured in serial zones of 100 μm proceeding from the bottom of the sinus floor (SF) up to the apical top of the biopsy. The gradient of nBV/TV within the augmentation area was determined by the vertical distribution of nBV/TV along these zones.

Results

In the premolar region, nBV/TV slightly declined from 20.4% in the zone adjacent to the SF to 17.7% at a distance of 8 mm. The gradient was steeper in the molar region: nBV/TV decreased from 18.7% to 12.8%. This decline was even more distinct when the volume fraction and the height of the residual bone of the SF were low.

Conclusions

nBF follows a gradient from native bone of the SF towards the apical part of the augmentation area. The distance to primordial bone thus plays a critical role for bone regeneration in MSFA, particularly in the molar region.

Injectable thermosensitive chitosan/gelatin-based hydrogel carried erythropoietin to effectively enhance maxillary sinus floor augmentation in vivo

OBJECTIVE

Maxillary sinus floor augmentation (MSFA) is commonly used to increase the alveolar bone height in the posterior maxilla before implant placement. In the present study, we evaluated if the injectable thermosensitive chitosan/β-sodium glycerophosphate disodium salt hydrate/gelatin (CS/GP/GA) hydrogel carried erythropoietin (EPO) could enhance the new bone formation for MSFA in vivo.

METHODS

EPO-CS/GP/GA hydrogel was prepared by ionic crosslinking. Then, characteristics of EPO-CS/GP/GA were evaluated by morphology, injectable property and pH on the gelling time (GT). The release profile of EPO was evaluated by enzyme linked immunosorbent assay (ELISA), and effects of EPO on proliferation and osteoblastic differentiation of bone marrow stromal cells (BMSC) were analyzed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and reverse transcription quantitative real-time PCR (RT-qPCR), respectively. Finally, EPO-CS/GP/GA was injected into the maxillary sinus floor of the rabbit to test the potential application for MSFA.

RESULTS

Results showed that GT was decreased with the increase of pH value. The GT was 110±15s at pH 7.0. SEM images showed that the CS/GP/GA hydrogel had a sponge network structure. Results from ELISA assay revealed that the cumulative release of EPO from the EPO-CS/GP/GA hydrogel reached 67% at 4h, and 94% at 15 days. MTT assay showed that EPO within EPO-CS/GP/GA hydrogel could significantly promote proliferation of BMSCs compared to control group (p<0.001) . Results of RT-qPCR assays demonstrated that the expression of Sp7, Runx2, Col I and Alp were significantly increased from EPO-CS/GP/GA group compared to control group on day 14 (p<0.001). Importantly, EPO-CS/GP/GA hydrogel could significantly induce bone formation (81.98mm³) compared with control group (43.11mm³) after 12 weeks post-implantation in vivo. The calculation of thickness of mesenchymal condensation indicated that thickness of mesenchymal condensation was significantly increased from EPO-CS/GP/GA group (∼121.4μm) compared to control group (∼37μm) resulting in enhancing intramembranous ossification.

SIGNIFICANCE

The EPO-CS/GP/GA hydrogel provides a novel strategy for MSFA with a minimally invasive way.

Sinus Floor Elevation and Antrostomy Healing: A Histomorphometric Clinical Study in Humans

OBJECTIVES

To compare the histomorphometric outcomes of biopsies collected from the antrostomy and from the alveolar crest of the maxillary sinus after a sinus-lift procedure.

MATERIAL AND METHODS

In 12 volunteers, sinus floor elevation was performed using collagenated corticocancellous porcine bone. Nine months after the surgery, 2 biopsies, 1 from the alveolar crest and 1 from the antrostomy, were collected for histological analysis.

RESULTS

Biopsies from 11 patients were available for histological analyses (n = 11). At the alveolar crest sites, the percentage of mineralized bone was 40.1 ± 14.1%, of bone marrow was 40.1 ± 18.0%, and of the xenograft was 14.7 ± 15.2%. Small amounts of soft tissue were found. At the antrostomy sites, the percentages of mineralized bone, bone marrow, and xenograft were 26.0 ± 10.8%, 23.4 ± 17.0%, and 28.2 ± 15.7%, respectively. Soft tissue was represented by 19.7 ± 19.4%.

CONCLUSION

Higher amounts of mineralized bone and bone marrow were found in the alveolar crest compared with the antrostomy.

Do osteoconductive bone substitutes result in similar bone regeneration for maxillary sinus augmentation when compared to osteogenic and osteoinductive bone grafts? A systematic review and frequentist network meta-analysis

The purpose of this network meta-analysis was to identify the most effective biomaterials producing higher new bone formation (NBF) and lower residual graft (RG) and connective tissue (CT) following maxillary sinus augmentation (MSA), and to generate a ranking based on their performance. The MEDLINE, Embase, and CENTRAL databases were searched to identify randomized controlled trials (RCTs) published until March 2018, evaluating histomorphometric outcomes after MSA. Predictor variables were autogenous bone (AB), allografts (AG), xenografts (XG), alloplastic bone (AP), AB+XG, AB+AP, AG+XG, XG+AP, and grafts combined with autologous platelet concentrates/recombinant growth factors, mesenchymal stem cells (MSCs), or recombinant bone morphogenetic proteins (BMPs). Outcome variables were NBF%, RG%, and CT%. Healing time was considered. The weighted mean difference (WMD) with 95% confidence interval (CI) was calculated via frequentist network meta-analysis using Stata software. Fifty-two RCTs (1483 biopsies) were included. At a healing time <6 months, AB was superior to AP (WMD-10.66%, 95% CI-16.38% to -4.94%) and XG (WMD-7.93%, 95% CI-15.11% to -0.75%) for NBF. Regarding CT, AB was superior to XG+AP, AP, MSCs, and XG. At a healing time ≥6 months, NBF was higher for AB than AP (WMD-7.06%, 95% CI-12.59% to -1.52%). RG was lower in AB than AP (WMD 12.03%, 95% CI 3.04% to 21.03%), XG (WMD 14.62%, 95% CI 4.25% to 24.98%), and growth factors (WMD 12.32%, 95% CI 0.04% to 24.60%). The three highest ranked biomaterials for increasing NBF were AG+XG (95%, very low quality evidence), growth factors (69.9%, low quality evidence), and AB alone (69.8%, moderate quality evidence). The three highest ranked biomaterials for decreasing RG were BMPs (88.8%, very low quality evidence), AB alone (81.5%, moderate quality evidence), and AB+AP (58.9%, very low quality evidence). Finally, XG+AP (84.7%, low quality evidence), AP alone (77.7%, moderate quality evidence), and MSCs (76.1%, low quality evidence), were the three highest ranked biomaterials for decreasing the amount of CT. Network meta-analysis provided moderate quality evidence that AB alone is probably the best option to obtain greater NBF after MSA in the first 6 months after surgery. Additionally, the results of this network meta-analysis support the hypothesis that osteoconductive bone substitute materials should be combined with osteogenic or osteoinductive grafts for superior histomorphometric outcomes in MSA.

Evaluation of Osteoconduction of Biphasic Calcium Phosphate Ceramic in the Calvaria of Rats: Microscopic and Histometric Analysis

(1) Background: Evaluate the osteoconduction capability of a biphasic calcium phosphate (BCP) ceramic composed of hydroxyapatite and β-tricalcium phosphate 60%/40% in a rat model. (2) Methods: In the calvarial bone of 54 adult male rats, 7-mm diameter critical size defects were performed. The animals were randomly allocated to three experimental groups according to the type of material: blood clot (BCG), blood clot covered with a bovine-derived collagen membrane (MBCG), and BCP ceramic covered with a bovine-derived collagen membrane (BCPG). In each group, 6 animals were euthanatized at post-operative days 7, 30, and 60 for histological and histometric analysis. (3) Results: The qualitative analysis revealed the persistence of the collagen membrane at seven days, with no relevant newly bone formation in all groups. At 30 days, centripetal bone formation was observed residual particles of the biomaterial surrounded by fibroblasts noted in the BCPG. At 60 days, while BCG and MBCG showed a partial maturation with the central part of the defect populated by a fibrous connective tissue, in the BCPG the critical area was entirely occupied by newly formed bone. In the intra groups analysis was noted a significant increase in new bone formation during the experimental period (p < 0.05). At 60 days, BCPG showed a higher percentage area of new bone formation (p < 0.05). (4) Conclusion: BCP promoted a new bone formation by osteoconduction and might be considered a valid alternative in bone regeneration procedures.

Does intraoperative perforation of Schneiderian membrane during sinus lift surgery causes an increased the risk of implants failure?: A systematic review and meta regression analysis

PURPOSE

There is still debate whether intraoperative Schneiderian membrane (SM) perforation in the maxillary sinus lift causes an increase the risk of implants failure. The aim of this study was to assess an association between SM perforation and implants loss following the maxillary sinus lift.

MATERIALS AND METHODS

A systematic review and meta-analysis of clinical studies assessing association between SM perforation and implants failure based on PRISMA was conducted. Three major databases were used to gather research dating from their respective inception up until March 2018. All clinical studies expressly reported the number of the SM perforation and implants loss that installed in the perforated and nonperforated sinuses were included. The statistical analyses used were Pearson's correlation, simple linear regression, and meta regression. The risk ratio (RR) of implant loss between perforated and nonperforated sites was estimated.

RESULTS

A total of 2947 patients with 3884 maxillary sinuses augmentations who received 7358 implants, enrolled in 58 studies were included in this study. There was a significant relationship between the implants' failure and SM perforation according to simple linear regression (P < .001) and meta regression analysis (P = .06). There was a significant decrease (moderate quality evidence) in implant loss in the nonperforated sinuses compared to perforated sunrises (RR = 2.17, CI: 1.52-3.10, P = .001). There was also no significant association between implant loss in the perforated sinuses and the surgical devices used (piezosurgical or rotary), surgical approach applied (lateral or crestal sinus lift), barrier membrane used and type of bone grafting materials.

CONCLUSION

The results of this study showed that an intraoperative SM perforation could increase the risk of implant failure after the sinus lift surgery.

Comparative Histological and Histomorphometric Results of Six Biomaterials Used in Two-Stage Maxillary Sinus Augmentation Model after 6-Month Healing

Objectives

To evaluate the performances of six different bone substitute materials used as graft in maxillary sinus augmentation by means of histological and histomorphometric analysis of bone biopsies retrieved from human subjects after a 6-month healing period.

Materials and Methods

Six consecutive patients (3 males, 3 females, aged 50-72 years), healthy, nonsmokers, and with good oral hygiene, presenting edentulous posterior maxilla with a residual bone crest measuring ≤ 4 mm in vertical height and 3 to 5 mm in horizontal thickness at radiographic examination, were selected to receive sinus augmentation and delayed implant placement. Under randomized conditions, sinus augmentation procedures were carried out using mineralized solvent-dehydrated bone allograft (MCBA), freeze-dried mineralized bone allograft (FDBA), anorganic bovine bone (ABB), equine-derived bone (EB), synthetic micro-macroporous biphasic calcium-phosphate block consisting of 70% beta-tricalcium phosphate and 30% hydroxyapatite (HA-β-TCP 30/70), or bioapatite-collagen (BC). After 6 months, bone core biopsies were retrieved and 13 implants were placed. Bone samples were processed for histological and histomorphometric analysis. CT scans were taken before and after surgery. After 4 months of healing, patients were restored with a provisional fixed acrylic resin prosthesis, as well as after further 2-4 months with a definitive cemented zirconia or porcelain-fused-to-metal crowns.

Results

There were no postoperative complications or implant failures. The histological examination showed that all biomaterials were in close contact with newly formed bone, surrounding the graft granules with a bridge-like network. No signs of acute inflammation were observed. The histomorphometry revealed 20.1% newly formed bone for MCBA, 32.1% for FDBA, 16.1% for ABB, 22.8% for EB, 20.3% for HA-β-TCP 30/70, and 21.4% for BC.

Conclusions

Within the limitations of the present investigation, all the six tested biomaterials showed good biocompatibility and osteoconductive properties when used in sinus augmentation procedures, although the FDBA seemed to have a better histomorphometric result in terms of newly formed bone and residual graft material. This trial is registered with ClinicalTrials.gov Identifier (Registration Number): NCT03496688.

Sinus Floor Augmentation With Ambient Blood and an Absorbable Collagen Sponge: A Prospective Pilot Clinical Study

PURPOSE

The aim of this study was to clinically, radiologically, and histologically evaluate a sinus augmentation technique using a resorbable collagen sponge to maintain space between the Schneiderian membrane and the residual crestal bone.

MATERIALS AND METHODS

Patients with partially edentulous maxillae were clinically and radiographically evaluated for implant placement. A total of 10 consecutive patients with the bone height for implant placement (<4.0 mm) were enrolled in the study. The lateral maxillary wall was surgically exposed and the Schneiderian membrane was carefully elevated. A collagen wound dressing was placed in the antral area between the sinus floor and the raised membrane. The vertical sinus floor height was calculated using cone-beam computed tomography before the surgical procedure (baseline) and at 6 months postoperative. Immediately after the second scan, a core biopsy was removed for histological evaluation. The biopsy site was then further prepared for implant placement in the same location.

RESULTS

Biopsies showed mature cancellous bone with a predominantly lamellar structure. Well-vascularized intertrabecular spaces were filled with connective tissue and bone marrow. Analysis of bone height changes showed significant mean (SD) differences before and after procedures in anterior (2.67 ± 0.62 mm and 11.15 ± 1.1 mm), medial (2.98 ± 0.55 mm and 10.96 ± 0.77 mm), and posterior (3.17 ± 0.91 mm and 10.63 ± 0.51 mm) maxillary jaw locations (P = 0.005).

CONCLUSION

The collagen sponge provided an effective substrate for osseous regeneration of the sinus floor.

Maxillary Sinus Floor Augmentation With Synthetic Bone Substitutes Compared With Other Grafting Materials: A Systematic Review and Meta-analysis

OBJECTIVE

To test the hypotheses of no differences in implant treatment outcome after maxillary sinus floor augmentation (MSFA) with synthetic bone substitutes (SBS) compared with other grafting materials applying the lateral window technique.

MATERIALS AND METHODS

A MEDLINE/PubMed, Embase and Cochrane Library search in combination with hand-search of selected journals was conducted.

RESULTS

Five randomized controlled trials with low risk of bias fulfilled the inclusion criteria. SBS disclosed high survival rate of suprastructures and implants with no significant differences compared to autogenous bone graft or xenograft. Meta-analysis revealed a patient-based implant survival rate of 0.98 (confidence interval: 0.89-1.08), indicating no differences between SBS and xenograft. SBS demonstrated significant less newly formed bone compared with autogenous bone graft, whereas no significant difference was revealed as compared to xenograft. High implant stability values, limited periimplant marginal bone loss, and few complications were reported with SBS.

CONCLUSIONS

There seem to be no differences in implant treatment outcome after MSFA with SBS compared to other grafting materials.

Histological analysis of the use of biphasic ceramics based on hydroxyapatite and β-tricalcium phosphate in maxillary sinus floor elevation surgery: pilot study

Abstract Objective To evaluate the bone repair associated with the use of biphasic ceramics based on hydroxyapatite and β-tricalcium phosphate (HA/TCP) in the procedures of maxillary sinus membrane elevation in human beings. Material and method Ten patients with a residual bone ridge in the posterior maxillary region between 3 mm and 5 mm in height were selected and indicated for procedures of bone grafting associated with maxillary sinus lift procedure. The maxillary sinuses were filled with HA/TCP, and after 8 months, the implants were implanted and a bone biopsy was collected with the aid of a trephine drill, which was then submitted to histological analysis for the evaluation of the composition of the grafted area. Result The histological description analysis of the biopsies revealed the presence of vital and immature bone tissue, juxtaposed to the biomaterial. Histomorphometric analysis showed that the biopsy composition was in average 28.8%, 27.4%, and 43.6% of bone tissue, biomaterial, and soft tissue, respectively. Conclusion The areas grafted with HA/TCP presented the adequate amount of bone formation that allowed the implantation of the implants. The success of the grafting procedure with this biomaterial was associated with its osteoconduction potential that allowed the formation of bone tissue in close contact with HA/TCP.

Effect of low-level laser therapy on the healing of sites grafted with coagulum, deproteinized bovine bone, and biphasic ceramic made of hydroxyapatite and β-tricalcium phosphate. In vivo study in rats

OBJECTIVE

The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) on the healing of biomaterial graft areas (i.e., coagulum, deproteinized bovine bone, and biphasic ceramics comprising hydroxyapatite and β-tricalcium phosphate).

MATERIAL AND METHODS

Ninety rats were divided into two groups according to laser irradiation use (λ 808 nm, 100 mW, φ ∼600 μm, seven sessions with 28 J of irradiation dose in total): a laser group and a control group. Each of these groups was divided into three subgroups of 15 animals each according to the type of biomaterial used: Coagulum (COA), deproteinized bovine bone (DBB), and hydroxyapatite/β-tricalcium phosphate (HA/βTCP). Biomaterials were inserted into Teflon domes, and these domes were grafted to the lateral aspect of the mandibular branch of the rats. The animals were sacrificed after 30, 60, and 90 days. Scarring patterns were evaluated by microtomography and histometry. The expression levels of BMP2, osteocalcin (OCN), and alkaline phosphatase (ALP) were evaluated by immunohistochemistry. The mRNA expression levels of ALP, BMP2, Jagged1, Osterix, Runx2, and TGFβ1 were determined by RT-qPCR.

RESULTS

The animals treated with LLLT exhibited increased mineralized tissues and bone, particularly after 90 days. These increases were associated with increased BMP2, OCN, and ALP protein expression and ALP, BMP2, and Jagged1 mRNA expression.

CONCLUSION

LLLT improved the osteoconductive potential of DBB and HA/βTCP grafts and bone formation in ungrafted areas. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc.

Histologic and Histomorphometric Comparison between Sintered Nanohydroxyapatite and Anorganic Bovine Xenograft in Maxillary Sinus Grafting: A Split-Mouth Randomized Controlled Clinical Trial

The presence of vital bone after maxillary sinus augmentation is crucial to enhance the quality of bone-implant interface, ensuring predictable long-term results. The aims of this RCT with split-mouth design were the histologic and histomorphometric comparison of two different biomaterials in sinus elevation after 6 months of healing and the evaluation of the clinical outcomes of implants inserted in the augmented areas after 12 months of prosthetic loading. Twenty-eight patients (10 females, 18 males) were treated with bilateral sinus floor elevation with lateral approach. Pure sintered nanohydroxyapatite (NHA) and anorganic bovine bone (ABB) were used as test and active control, respectively. After six months, 52 bone biopsies were harvested from 26 patients, and 107 implants were inserted in the augmented areas. Histomorphometry showed that, in the two groups, vital bone percentages were 34.9 ± 15% (NHA) and 38.5 ± 17% (ABB) (p = 0.428), marrow spaces percentages were 44.5 ± 18% (NHA) and 43.5 ± 23% (ABB) (p = 0.866), and residual graft percentages were 20.6 ± 13% (NHA) and 22.3 ± 12% (ABB) (p = 0.638). After 6 months of healing, no statistically significant difference was present in histomorphometric outcomes between NHA and ABB groups. Implant survival rate in NHA group after 12 months of loading was 96.4%, showing no statistically significant differences with ABB group.