Maxillary sinus augmentation with Bio-Oss particles: a light, scanning, and transmission electron microscopy study in man

Bone volume and height changes for lateral window sinus floor elevation using two types of deproteinized bovine bone mineral: A retrospective cohort study of 1-4 years

OBJECTIVE

To compare bone volume and height changes of two types of deproteinized bovine bone mineral (DBBM) for lateral window sinus floor elevation (LSFE) with simultaneous implant placement.

MATERIALS AND METHODS

This retrospective cohort study involved 72 patients who underwent LSFE using low-temperature sintered cancellous bone-derived DBBM (C-DBBM) or high-temperature two-step sintered epiphyseal-derived DBBM (E-DBBM). Cone-beam computed tomography (CBCT) was acquired preoperatively, immediately postoperatively, 6 months and 1-4 years post-surgery. Bone volume (BV), apical bone height (ABH), endo-sinus bone gain (ESBG), and crestal bone level (CBL) were evaluated through three-dimensional fitting and superimposition. Linear mixed models (LMM) were employed to analyze factors influencing the reduction of BV (ΔBV) and ESBG (ΔESBG).

RESULTS

The E-DBBM group showed no significant change in BV 1-4 years post-surgery, while the C-DBBM group demonstrated a significant reduction (p = .006) with volume stability of 85.86%. Bone height in the E-DBBM group increased at 6 months and subsequently decreased at 1-4 years (p = .003). In the C-DBBM group, it decreased at 6 months (p = .014), then further decreased at 1-4 years (p = .001). ΔESBG was lower in the E-DBBM group than the C-DBBM group from immediate postoperative to 1-4 years (p = .009). LMM showed graft material type was the primary factor influencing ΔBV (p = .026) and ΔESBG (p = .003).

CONCLUSIONS

Within the limitations of this study, both types of DBBM could achieve favorable clinical outcomes. E-DBBM demonstrated enhanced stability in maintaining bone volume and height.

Clinical and radiographic outcomes of lateral sinus floor elevation with simultaneous hydrophilic implants placement: A retrospective study of 2-5 years

AIMS

To investigate the clinical and radiographic outcomes of a chemically modified sandblasted large-grit acid-etched implant (hydrophilic) in lateral sinus floor elevation (LSFE), compared with a conventional one (hydrophobic).

MATERIALS AND METHODS

A retrospective study design was adopted. Patients who received LSFE with simultaneous implant placement were recruited. According to different types of implant surfaces, patients were divided into two groups (the hydrophilic group and the hydrophobic group). Implant survival rate (SR), endo-sinus bone stability on the radiographs, mean probing depths, percentage of bleeding on probing, marginal bone loss, and patient satisfaction were evaluated.

RESULTS

A total of 106 patients with 180 implants (hydrophilic:101, hydrophobic:79) in 119 maxillary sinuses were included. The follow-up period ranged from 2 to 5 years. Three hydrophobic implants and one hydrophilic implant in four different patients failed. The SR of the hydrophilic group was higher than that of the hydrophobic group but without a significant difference (p > .05). The change and change rate of endo-sinus bone height (ΔESBH and RΔESBH) and bone volume (ΔESBV and RΔESBV) in the hydrophilic group were less than those in the hydrophobic group, with a significant difference at 6 months after implantation. No other significant difference was found between the two groups.

CONCLUSION

Within the limitations of this study, both hydrophilic and hydrophobic implants were suitable for LSFE with predictable clinical outcomes. Meanwhile, hydrophilic implants could contribute to the grafted endo-sinus bone stability during healing time.

Clinical outcomes of periodontal regenerative therapy with carbonate apatite granules for treatments of intrabony defects, Class II and Class III furcation involvements: A 9-month prospective pilot clinical study

Introduction

Carbonated apatite (CO3Ap) has unique properties as an alloplastic bone substitute and has been reported the safety and efficacy for bone regeneration. However, no previous studies reported the clinical application of CO3Ap for periodontal regeneration therapy. The aim of this study was to evaluate the safety and efficacy of periodontal regeneration with CO3Ap in treating intrabony defects, Class II and Class III furcation involvement (FI).

Methods

A single-arm and single-center prospective pilot clinical study was performed to verify the safety and efficacy of CO3Ap in patients with periodontitis. A total of four patients with seven teeth, including three deep intrabony defects, two Class II FI, and two Class III FI, were treated with CO3Ap. The clinical parameters, including probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP), tooth mobility (Mo), Plaque index (PI), and Gingival index (GI) were evaluated at baseline, 6 months, and 9 months after the surgery. Radiographic analysis was conducted on images of dental X-ray and cone beam computed tomography (CBCT) at baseline and 9 months post-surgery.

Results

The postoperative healing in all cases was uneventful, with no abnormal bleeding, pain, or swelling. The mean PPD reduction and CAL gain were 5.0 ± 1.0 mm, 4.5 ± 0.7 mm, 1.5 ± 0.7 mm, and 4.7 ± 1.2 mm, 4.5 ± 0.7 mm, 0.0 mm for intrabony defect, Class II and Class III FI, respectively. According to radiographic analysis, linear bone height in intrabony defects and vertical subclassification of FI in Class II FI were improved.

Conclusions

The clinical application of CO3Ap for the treatment of intrabony defects and Class II FI could be effective for periodontal regeneration, although its efficacy in treating Class III FI might be limited. Despite the limitations of this study, the findings in this study suggested that CO3Ap has the potential to be a promising bone graft substitute for periodontal regeneration.

Bone regeneration in implant dentistry: Which are the factors affecting the clinical outcome?

The key factors that are needed for bone regeneration to take place include cells (osteoprogenitor and immune-inflammatory cells), a scaffold (blood clot) that facilitates the deposition of the bone matrix, signaling molecules, blood supply, and mechanical stability. However, even when these principles are met, the overall amount of regenerated bone, its stability over time and the incidence of complications may significantly vary. This manuscript provides a critical review on the main local and systemic factors that may have an impact on bone regeneration, trying to focus, whenever possible, on bone regeneration simultaneous to implant placement to treat bone dehiscence/fenestration defects or for bone contouring. In the future, it is likely that bone tissue engineering will change our approach to bone regeneration in implant dentistry by replacing the current biomaterials with osteoinductive scaffolds combined with cells and mechanical/soluble factors and by employing immunomodulatory materials that can both modulate the immune response and control other bone regeneration processes such as osteogenesis, osteoclastogenesis, or inflammation. However, there are currently important knowledge gaps on the biology of osseous formation and on the factors that can influence it that require further investigation. It is recommended that future studies should combine traditional clinical and radiographic assessments with non-invasive imaging and with patient-reported outcome measures. We also envisage that the integration of multi-omics approaches will help uncover the mechanisms responsible for the variability in regenerative outcomes observed in clinical practice.

Preclinical evaluation of the effect of periodontal regeneration by carbonate apatite in a canine one-wall intrabony defect model

Objective

This study aimed to histologically compare periodontal regeneration of one-wall intrabony defects treated with open flap debridement, β-tricalcium phosphate (β-TCP), and carbonate apatite (CO₃Ap) in dogs.

Methods

The mandibular third premolars of four beagle dogs were extracted. Twelve weeks after the extraction, a one-wall bone defect of 4 mm × 5 mm (mesio-distal width × depth) was created on the distal side of the mandibular second premolar and mesial side of the fourth premolar. Each defect was randomly allocated to open flap debridement (control group), periodontal regeneration utilizing β-TCP, or CO₃Ap. Eight weeks after the surgery, histologic and histometric analyses were performed.

Results

No ankylosis, infection, or acute inflammation was observed at any of the experimental sites. Newly formed bone and cementum were observed in all experimental groups. The mineral apposition rate of the alveolar bone crest was higher in the CO₃Ap group than in the control and β-TCP groups. The ratio of the new bone area was significantly higher in the CO₃Ap group than in the control group (P < 0.05). The bone contact percentage of the residual granules was significantly higher in the CO₃Ap group than in the β-TCP group (P < 0.05).

Conclusion

Although this study has limitations, the findings revealed the safety and efficacy of CO₃Ap for periodontal regeneration in one-wall intrabony defects in dogs, and CO₃Ap has a better ability to integrate with bone than β-TCP.

Characterization of a cotton-wool like composite bone graft material

Bone graft materials are applied in patients to augment bone defects and enable the insertion of an implant in its ideal position. However, the currently available augmentation materials do not meet the requirements of being completely resorbed and replaced by new bone within 3 to 6 months. A novel electrospun cotton-wool like material (Bonewool^®, Zurich Biomaterials LLC, Zurich, Switzerland) consisting of biodegradable poly(lactic-co-glycolic) acid (PLGA) fibers with incorporated amorphous ß-tricalcium phosphate (ß-TCP) nanoparticles has been compared to a frequently used bovine derived hydroxyapatite (Bio-Oss^®, Geistlich Pharma, Wolhusen, Switzerland) in vitro. The material composition was determined and the degradation behavior (calcium release and pH in different solutions) as well as bioactivity has been measured. Degradation behavior of PLGA/ß-TCP was generally more progressive than for Bio-Oss^®, indicating that this material is potentially completely resorbable. Graphical abstract.

Histological and Biological Response to Different Types of Biomaterials: A Narrative Single Research Center Experience over Three Decades

Background: In more than three decades of work of the Retrieval Bank of the Laboratory for Undemineralized Hard Tissue Histology of the University of Chieti-Pescara in Italy, many types of biomaterials were received and evaluated. The present retrospective review aimed to evaluate the histological and biological aspects of the evaluated bone substitute biomaterials. Methods: In the present study, the authors prepared a retrospective analysis after the screening of some databases (PubMed, Scopus, and EMBASE) to find papers published from the Retrieval Bank of the Laboratory for Undermineralized Hard Tissue Histology of the University of Chieti-Pescara analyzing only the papers dealing with bone substitute biomaterials and scaffolds, in the form of granules and block grafts, for bone regeneration procedures. Results: Fifty-two articles were found, including in vitro, in vivo, and clinical studies of different biomaterials. These articles were evaluated and organized in tables for a better understanding. Conclusions: Over three decades of studies have made it possible to assess the quality of many bone substitute biomaterials, helping to improve the physicochemical and biological properties of the biomaterials used in daily clinical practice.

A WNT protein therapeutic accelerates consolidation of a bone graft substitute in a pre-clinical sinus augmentation model

AIM

Autologous bone grafts consolidate faster than bone graft substitutes (BGSs) but resorb over time, which compromises implant support. We hypothesized that differences in consolidation rates affected the mechanical properties of grafts and implant stability, and tested whether a pro-osteogenic protein, liposomal WNT3A (L-WNT3A), could accelerate graft consolidation.

MATERIALS AND METHODS

A transgenic mouse model of sinus augmentation with immunohistochemistry, enzymatic assays, and histology were used to quantitatively evaluate the osteogenic properties of autografts and BGSs. Composite and finite element modelling compared changes in the mechanical properties of grafts during healing until consolidation, and secondary implant stability following remodelling activities. BGSs were combined with L-WNT3A and tested for its osteogenic potential.

RESULTS

Compared with autografts, BGSs were bioinert and lacked osteoprogenitor cells. While in autografted sinuses, new bone arose evenly from all living autograft particles, new bone around BGSs solely initiated at the sinus floor, from the internal maxillary periosteum. WNT treatment of BGSs resulted in significantly higher expression levels of pro-osteogenic proteins (Osterix, Collagen I, alkaline phosphatase) and lower levels of bone-resorbing activity (tartrate-resistant acid phosphatase activity); together, these features culminated in faster new bone formation, comparable to that of an autograft.

CONCLUSIONS

WNT-treated BGSs supported faster consolidation, and because BGSs typically resist resorption, their use may be superior to autografts for sinus augmentation.

Radiographic Analysis of Graft Dimensional Changes after Lateral Maxillary Sinus Augmentation with Heterologous Materials and Simultaneous Implant Placement: A Retrospective Study in 18 Patients

Background: This investigation aimed to radiographically assess the variations of graft dimension following maxillary sinus augmentation by the lateral approach. Methods: Eighteen patients (seven males), with a mean age at surgery of 66.5 ± 9.8 (range 52−82) years, were unilaterally treated. Thirty-five dental implants were positioned in the posterior maxilla simultaneously to grafting with heterologous biomaterials. Intraoral radiographs taken at the time of surgery, after six months, and at the longest follow-up (up to nine years after implant placement) were analyzed. The following distances were measured: mesio-distal width of the graft, vertical distance from implant apex to most coronal level of the graft, distance from the mesial aspect of the (mesial) implant to the mesial graft extension; distance from the distal aspect of the (distal) implant to the distal graft extension, and graft height along the implant axis. The dimensional changes with respect to baseline, after six months and at the longest follow-up were calculated. Results: The patient-based mean follow-up was 38.3 ± 30.1 months (range 12−108 months). The mean residual bone height at the mesial and distal aspect of the implants was 3.19 ± 2.05 mm and 2.65 ± 1.60 mm, respectively (p = 0.38). The mean graft width at baseline was 27.95 ± 5.23 mm, and the mean graft width reduction was 10.2 ± 12.7% (2.98 ± 3.62 mm) and 11.3 ± 14.4% (3.36 ± 4.08 mm) at six months and at the latest follow-up. The change was significant at six months (p = 0.005), but did not show significant further variation (p = 0.11). On the mesial and distal aspect, the mean graft extension decreased by 1.56 ± 2.67 mm and 0.84 ± 2.71 mm at the latest follow-up. No significant difference between mesial and distal changes was found (p = 0.24), suggesting that the biomaterial is resorbed homogeneously on both sides. The mean graft height was 11.92 ± 2.53 mm at baseline and decreased by 9.3 ± 9.05% (1.11 ± 1.09 mm) at six months (p < 0.001). Non-significant further changes were found at the latest follow-up (p = 0.10). Conclusions: after early remodeling, heterologous bone substitutes showed a good dimensional stability in the mid-term for maxillary sinus augmentation.

Radiographic Analysis of Graft Dimensional Changes in Transcrestal Maxillary Sinus Augmentation: A Retrospective Study

Background. The maxillary sinus lift is a popular and predictable technique associated with implant-supported rehabilitation of the severely atrophic maxilla. The aim of the present retrospective study was to investigate the effectiveness of transcrestal maxillary sinus augmentation and the graft resorption pattern using different heterologous bone substitutes. Methods. A total of 75 sinus-grafting procedures were performed and 89 implants were placed in 66 patients, 24 males and 42 females, with mean age 67.9 ± 10.64 years (range 43−84 years). Nineteen subjects were smokers. The mean follow-up period was 93.33 ± 54.71 months (range 14−240 months). Clinical and radiographical evaluations were performed. Graft height and width were measured at baseline and at the latest follow-up. Results. Mesiodistal and vertical resorption averaged 9.3 ± 20.7% (standard deviation), and 5.04 ± 9.9% of the postoperative size, respectively, considering the graft as the unit. Linear regression analysis showed that graft resorption in both the vertical and the mesiodistal dimension is independent of the follow-up time. Conversely, there was a trend for greater resorption when increasing the postoperative graft size, in both vertical (p = 0.001) and horizontal (p = 0.007) dimensions. When grouping the dimensional changes by graft particle size (only small (<300 μm) particles, combination of small and medium (>500 μm)/large (>1000 μm) particles, and only medium/large particles), there was a trend for greater resorption associated with smaller particles, but it was not significant; neither in the mesiodistal nor in the vertical dimension (p = 0.17 and p = 0.25, respectively). No implant was lost during the observation period. In conclusion, the transcrestal technique for maxillary sinus augmentation documented a high level of predictability. The low clinical morbidity and the contextual dental implant positioning is clinically useful in relation to a significant reduction of the time required for implant restoration, a consistent decrease of the number of surgical phases, and a cost-effectiveness approach for the rehabilitation. The graft resorption pattern in all cases was compatible with persistent implant protection and support.

Radiographic assessment of deproteinized bovine bone mineral (DBBM) and collagen-stabilized DBBM for transalveolar sinus floor elevation: A 2-year retrospective cohort study

BACKGROUND

Theoretically, collagen-stabilized deproteinized bovine bone mineral (DBBM-C) has better operability compared with DBBM. DBBM-C avoids dispersing during the transalveolar sinus floor elevation (TSFE) because of its block shape.

PURPOSE

To evaluate radiological changes of using DBBM-C in TSFE.

MATERIALS AND METHODS

Patients who received TSFE using DBBM (Bio-Oss®) or DBBM-C (Bio-Oss® collagen) with simultaneous implantation were recruited. Graft bone height apically (aGH), endo-sinus bone gain (ESBG), and crest bone level (CBL) were assessed through panoramic radiograph and cone beam computed tomography (CBCT).

RESULTS

A total of 138 patients (138 implants) were retrospectively enrolled. After 2 years of implantation, the incidence of postoperative complications was 4.2% (95% CI: 0.9%-11.7%) and 4.5% (95% CI: 0.9%-12.7%) for DBBM and DBBM-C groups, respectively. Measured in panoramic radiograph, ΔaGH of DBBM-C (1.8 mm, SD: 1.4, 95% CI: 1.2-2.4, P = 0.044) group was significantly higher than that of DBBM (1.2 mm, SD: 1.4, 95% CI: 0.7-1.7) after 24 months. No significant differences for ΔCBL were noted during the entire observation period. Measured through CBCT, ESBG was 5.0 (SD: 1.8, 95% CI: 4.1-5.8) mm in DBBM group and 4.6 (SD: 1.6, 95% CI: 3.9-5.3) mm in DBBM-C group 24 months after implantation. The aGH value of DBBM-C group was significantly higher compared with DBBM in CBCT (OR = 1.4, 95% CI: 1.1-1.9, P = 0.020).

CONCLUSIONS

DBBM-C could achieve similar bone generation as DBBM in TSFE. Both materials could maintain aGH, ESBG, and CBL relatively stable 2 years after implantation.

Innovative Concepts and Recent Breakthrough for Engineered Graft and Constructs for Bone Regeneration: A Literature Systematic Review

BACKGROUND

For decades, regenerative medicine and dentistry have been improved with new therapies and innovative clinical protocols. The aim of the present investigation was to evaluate through a critical review the recent innovations in the field of bone regeneration with a focus on the healing potentials and clinical protocols of bone substitutes combined with engineered constructs, growth factors and photobiomodulation applications.

METHODS

A Boolean systematic search was conducted by PubMed/Medline, PubMed/Central, Web of Science and Google scholar databases according to the PRISMA guidelines.

RESULTS

After the initial screening, a total of 304 papers were considered eligible for the qualitative synthesis. The articles included were categorized according to the main topics: alloplastic bone substitutes, autologous teeth derived substitutes, xenografts, platelet-derived concentrates, laser therapy, microbiota and bone metabolism and mesenchymal cells construct.

CONCLUSIONS

The effectiveness of the present investigation showed that the use of biocompatible and bio-resorbable bone substitutes are related to the high-predictability of the bone regeneration protocols, while the oral microbiota and systemic health of the patient produce a clinical advantage for the long-term success of the regeneration procedures and implant-supported restorations. The use of growth factors is able to reduce the co-morbidity of the regenerative procedure ameliorating the post-operative healing phase. The LLLT is an adjuvant protocol to improve the soft and hard tissues response for bone regeneration treatment protocols.

A New Anorganic Equine Bone Substitute for Oral Surgery: Structural Characterization and Regenerative Potential

Different xenogeneic inorganic bone substitutes are currently used as bone grafting materials in oral and maxillo-facial surgery. The aim of the present study was to determine the physicochemical properties and the in vivo performance of an anorganic equine bone (AEB) substitute. AEB is manufactured by applying a process involving heating at >300 °C with the aim of removing all the antigens and the organic components. AEB was structurally characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier-transformed infrared (FT-IR) spectroscopy and compared to the anorganic bovine bone (ABB). In order to provide a preliminary evaluation of the in vivo performance of AEB, 18 bone defects were prepared and grafted with AEB (nine sites), or ABB (nine sites) used as a control, in nine Yucatan Minipigs. De novo bone formation, residual bone substitute, as well as local inflammatory and tissue effects were histologically evaluated at 30 and 90 days after implantation. The structural characterization showed that the surface morphology, particle size, chemical composition, and crystalline structure of AEB were similar to cancellous human bone. The histological examination of AEB showed a comparable pattern of newly formed bone and residual biomaterial to that of ABB. Overall, the structural data and pre-clinical evidence reported in the present study suggests that AEB can be effectively used as bone grafting material in oral surgery procedures.

Application of deproteinized bovine bone mineral as proangiogenic scaffold for alveolar bone formation in beagle dogs

Alveolar bone repair after tooth extraction is essential after oral surgeries. Various grafting materials are used to promote the regeneration of lost alveolar bone. This study analysed the morphological features of the tissue regeneration process using deproteinized bovine bone mineral (DBBM). DBBM was used to densely fill the extraction sockets in beagle dogs. Following resin casting of the vasculature, stereomicroscopy and scanning electron microscopy were used to observe blood vessels and hard tissues in haematoxylin and eosin-stained sections on postoperative days 14, 30 and 90 in conjunction with vascular endothelial growth factor (VEGF) immunostaining to evaluate alveolar bone vascularization. On day 14 post-operation, the DBBM granules tightly filled the extraction sockets, maintained alveolar margin height and formed a scaffold for aiding angiogenesis and new bone formation. On day 30, new bone formation was observed around the DBBM granules. By day 90, bone tissue regeneration progressed in both groups but was more pronounced in the DBBM group. Alveolar margin height was maintained in the DBBM group throughout the study. Furthermore, VEGF expression in the DBBM group was detected around newly formed bone. We conclude that DBBM acts as a suitable scaffold for new bone generation, as well as angiogenesis around healing alveolar bone, and that it has the potential to play a key role in vascularization and bone formation.

Ridge preservation applying a novel hydrogel for early angiogenesis and osteogenesis evaluation: an experimental study in canine

Ridge preservation is universally acknowledged as the conventional method for the post-extraction healing yet there are no standard materials for the ideal healing outcome. Herein, a composite gel comprising gelatin nanoparticles (GNPs) and injectable platelet-rich-fibrin (i-PRF) as the potential candidate for extracted socket healing is introduced. The combination of GNPs and i-PRF not only possesses favorable mechanical properties to withstand external force but also accelerate the blood clotting time significantly. In addition, six beagle dogs were adopted to assess the angiogenic and osteogenic capacity of GNPs+i-PRF gel in vivo. The GNPs+i-PRF gel significantly produced the most blood vessels area, woven bone and low osteoclast activity in extracted sockets at 2 weeks postoperation and remarkably generated corticalization on the alveolar ridge crest at 8 weeks postoperation according to histological results. Therefore, GNPs+i-PRF gel can be recommended as the candidate grafting material regarding ridge preservation for its cost effectiveness, excellent biocompatibility, facilitation of blood clotting and favorable capacity of promoting angiogenesis and osteogenesis.

Mutual chemical effect of autograft and octacalcium phosphate implantation on enhancing intramembranous bone regeneration

This study examined the effect of a mixture of octacalcium phosphate (OCP) and autologous bone on bone regeneration in rat calvaria critical-sized defect (CSD). Mechanically mixed OCP and autologous bone granules (OCP+Auto), approximately 500 to 1000 μm in diameter, and each individual material were implanted in rat CSD for 8 weeks, and subjected to X-ray micro-computed tomography (micro-CT), histology, tartrate-resistant acid phosphatase (TRAP) staining, and histomorphometry for bone regeneration. Osteoblastic differentiation from mesenchymal stem cells (D1 cells) was examined in the presence of non-contacting materials by alkaline phosphatase (ALP) activity for 21 days. The material properties and medium composition before and after the incubation were determined by selected area electron diffraction (SAED) under transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and chemical analysis. The results showed that while bone formation coupled with TRAP-positive osteoclastic resorption and cellular ALP activity were the highest in the Auto group, a positive effect per OCP weight or per autologous bone weight on ALP activity was found. Although the OCP structure was maintained even after the incubation (SAED), micro-deposits were grown on OCP surfaces (TEM). Fibrous tissue was also exposed on the autologous bone surfaces (SEM). Through FT-IR absorption, it was determined that bone mineral-like characteristics of the phosphate group increased in the OCP + Auto group. These findings were interpreted as a structural change from OCP to the apatitic phase, a conclusion supported by the medium degree of saturation changes. The results demonstrate the mutual chemical effect of mixing OCP with autologous bone as an active bone substitute material.

A comparative study on fabrication techniques of gelable bone matrix derived from porcine tibia

Recently, several types of native tissues have been enzymatically digested to prepare hydrogels that have natural-mimic extracellular matrix (ECM) proteins, architecture, and biologic activities. However, the residual detergents and salts remaining in the hydrogel may cause some undesirable effects on compatibility, functionality, and bioactivity of the material. In this study, we enzymatically digested the demineralized and decellularized bone matrix (DDBM) and adopted two common methods that included dialysis against distilled water and acetone precipitation for sample desalting. Efficiency in salt removal, protein preservation, gelation ability, and in vivo biocompatibility and function were compared to the DDBM digest without a desalting treatment. After lyophilization, the dialyzed, precipitated, and non-desalted DDBM digests all exhibited cotton-like texture and were water-soluble; however, only the precipitated DDBM digest could be gelled. We also found that the method of acetone precipitation could effectively remove salt from the DDBM digest while preserving of multiple proteins from the native bone and internal porous structure. A total of 57 proteins were identified by mass spectrometry in the precipitated DDBM digest and the majority of these proteins are critical to overall protein assembly, scaffold structure and stability, and cell-activities. Additionally, the precipitated DDBM digest possessed enhanced biocompatibility and osteointegration in repairing a cranial bone defect in Sprague-Dawley (SD) rat. In conclusion, the soluble, biodegradable, and biocompatible natures of the precipitated DDBM digest allow its usage in bone tissue engineering as a protein carrier because of its resemblance to native bone-like protein composite and operative flexibility.

A biodegradable gelatin-based nanostructured sponge with space maintenance to enhance long-term osteogenesis in maxillary sinus augmentation

The search for bone substitutes that are biodegradable, ensure space maintenance, and have osteogenic predictability, is ongoing in the field of sinus augmentation. We thus compared the bone regeneration potential of nanostructured sponges (NS-Sponge) with that of collagen-stabilized inorganic bovine bones (BO-Collagen), gelatin sponges (Gelatin), and blood clots (Cont) in sinus augmentation of rabbits. NS-Sponge was prepared by thermally induced phase separation with porogen leaching techniques. All the materials were non-hemolytic and cytocompatible. The porous and nanofibrous NS-Sponge showed better dimensional stability to support cell growth and osteogenic differentiation. In vivo, the sinus membrane collapsed in Cont and Gelatin, while BO-Collagen and NS-Sponge maintained the elevated height as assessed by come-beam computed tomography. Limited bone regeneration was observed in Cont and Gelatin. In the entire implanted area, histological analysis revealed a higher percentage of new bone area at 4 weeks of BO-Collagen treatment; however, a significantly greater increase in new bone area was observed after 12 weeks of NS-Sponge treatment. The 12-week remnant NS-Sponge material was significantly lower than the 4-week remnant material. Overall, NS-Sponge may be highly recommended for sinus augmentation, as it exhibits numerous advantages, including excellent operability, clear imaging characteristics, space maintenance, biodegradability, and superior osteogenic potential.

Effectiveness of strontium-doped brushite, bovine-derived hydroxyapatite and synthetic hydroxyapatite in rabbit sinus augmentation with simultaneous implant installation

Various bone substitutes have been applied in sinus augmentation (SA) to overcome insufficient bone height at the posterior maxilla region caused by pneumatized sinus and severe alveolar bone resorption after teeth loss. However, their effectiveness in SA needs to be further elucidated. In this study, strontium-doped brushite (Sr-DCPD), a new bone substitute, together with bovine-derived hydroxyapatite (bHA) and synthetic hydroxyapatite (sHA) was used in rabbit maxillary SA with simultaneous implant installation. The sinus space-keeping capacity, resorption rate, osteoconductivity, and mechanical properties of regenerated bone, were evaluated by micro-computed tomography (CT), histological analysis, and mechanical testing. Sr-DCPD exhibited the best osteoconductivity and new bone formation (<4 weeks), but its final bone regeneration and removal torque of implants at week 12 were the lowest, mainly due to its poor space-keeping capacity and fast resorption. bHA exhibited the best space-keeping capacity and slowest resorption rate, but relative lower final bone volume and mechanical properties, while sHA showed good space-keeping capacity, slower resorption rate, and the best final bone formation and mechanical properties. sHA was most effective for SA and bHA was also an acceptable bone substitute; however, Sr-DCPD was least effective and not suitable in SA by itself.

Comparison of the vertical bone defect healing abilities of carbonate apatite, β-tricalcium phosphate, hydroxyapatite and bovine-derived heterogeneous bone

The treatment of vertical bone defects caused by severe periodontal disease requires the regeneration of periodontal tissue. Although various bone substitutes have been clinically applied to vertical bone defect correction, the evaluation of these materials in periodontal tissue remains incomplete. The purpose of this study was to examine the bone regeneration abilities of various bone substitutes including Cytrans, Cerasorb, Neobone and Bio-Oss in a 3-wall bone defect animal model. All of these bone substitutes showed a similar healing ability to periodontal ligament and cementum. However, Cytrans showed the fastest bone healing ability compared with the other materials at 4 weeks post-transplantation. In addition, the recruitment of osteoclasts and endothelial cells was observed in Cytrans grafts at 4 weeks, but only detected at 8 weeks in the other materials. These results suggest that Cytrans promotes faster bone healing by inducing bone remodeling and angiogenesis.

Histological Evaluation of a New Beta-Tricalcium Phosphate/Hydroxyapatite/Poly (1-Lactide-Co-Caprolactone) Composite Biomaterial in the Inflammatory Process and Repair of Critical Bone Defects

Background: The use of biomaterials is commonplace in dentistry for bone regeneration. The aim of this study was to evaluate the performance of a new alloplastic material for bone repair in critical defects and to evaluate the extent of the inflammatory process. Methods: Forty-five New Zealand rabbits were divided into five groups according to evaluation time (7, 14, 30, 60, 120 days), totaling 180 sites with six-millimeter diameter defects in their tibiae. The defects were filled with alloplastic material consisting of poly (lactide-co-caprolactone), beta-tricalcium phosphate, hydroxyapatite and nano-hydroxyapatite (BTPHP) in three different presentations: paste, block, and membrane. Comparisons were established with reference materials, such as Bio-ossTM, Bio-oss CollagenTM, and Bio-gideTM, respectively. The samples were HE-stained and evaluated for inflammatory infiltrate (scored for intensity from 0 to 3) and the presence of newly formed bone at the periphery of the defects. Results: Greater bone formation was observed for the alloplastic material and equivalent inflammatory intensity for both materials, regardless of evaluation time. At 30 days, part of the synthetic biomaterial, regardless of the presentation, was resorbed. Conclusions: We concluded that this novel alloplastic material showed osteoconductive potential, biocompatibility, low inflammatory response, and gradual resorption, thus an alternative strategy for guided bone regeneration.

Inflammatory response and macrophage polarization using different physicochemical biomaterials for oral and maxillofacial reconstruction

Knowledge about the action of immune system in the recognition of biomaterials has been extremely helpful when it comes about understanding host response and biomaterials' fate in human body. This study aimed to investigate inflammatory response and macrophage polarization during bone healing process of rat's calvaria critical defects using different bone materials in order to evaluate their influence on bone repair and on the quality of the newly formed bone tissue. Eighty male albinus Wistar rats underwent surgical procedure for the confectioning of a 5-mm diameter bone defect in their right parietal bone, and divided in four groups (n = 20 each), according the biomaterial: AG - Control, particulate intramembranous autogenous bone graft, HA/TCP - particulate biphasic calcium phosphate with HA/TCP (60/40), DBB - particulate deproteinized bovine bone, VC - particulate bioactive vitroceramic. After 3, 7, 21, and 45 days, the specimens were removed and prepared for microcomputed tomography (microCT), light and polarized microscopy, immunohistochemical analysis, and histomorphometry. No significant differences were detected considering percentage of leukocytes among the groups and periods, as well as in relation to immunolabeling for inflammatory (M1) and reparative (M2) macrophages. However, immunolabeling for bone marker indicated a delayed osteoblast differentiation in VC group, resulting in a decrease in mineralized bone matrix parameters in this group, revealed by microCT. In addition, AG and HA/TCP presented a satisfactory bone collagenous content. Despite the distinct origins and physicochemical properties of the tested biomaterials, they presented similar immune-inflammatory responses in the present experimental model, influencing bone-related proteins and bone quality, which must be considered according to their use.

Improvement of bone repair with l-PRF and bovine bone in calvaria of rats. histometric and immunohistochemical study

OBJECTIVES

The effect of leucocyte- and platelet-rich fibrin (L-PRF), associated with DBBM (deproteinized bovine bone mineral; Bio-Oss®) was investigated and compared with autogenous bone graft as a standard material for filling bone defects.

MATERIAL AND METHODS

A defect of 5 mm in diameter was performed in 40 calvaria of rats. The animals were divided into 5 groups and received blood clot (CO), autogenous bone (AUT), DBBM (BIO), L-PRF, or DBBM associated with L-PRF (BIO-LPRF). After 4 and 8 weeks, bone regeneration was assessed by histometric and immunohistochemical analyses.

RESULTS

The highest mean percentage of bone formation found at 4 and 8 weeks was observed for the BIO-L-PRF group (54.0% ± 2.8 and 63.6% ± 2.2). The lowest mean percentage at 4 and 8 weeks was observed for the CO group (16.7% ± 2.5 and 20.5% ± 1.0). There was statistical similarity among the AUT, BIO, and L-PRF groups. The expressions OC, RUNX 2, and VEGF showed a favorable aspect in the formation of new bone for BIO-L-PRF. VEGF was the marker with the highest expression because it was related to the initial healing process, promoting the migration and proliferation of endothelial cells in the region of the defect. Even after weeks, VEGF maintained a moderate expression.

CONCLUSIONS

The association of L-PRF with DBBM improved bone repair when these biomaterials were inserted into the defects of the calvaria of rats.

CLINICAL RELEVANCE

This reinforces the good performance of bovine bone and L-PRF as filler materials, especially when associated.

Distinct healing pattern of maxillary sinus augmentation using the vitroceramic Biosilicate®: Study in rabbits

OBJECTIVES

To follow healing process of augmented maxillary sinus in rabbits analyzing the histological pattern of bone tissue formation, along with the osteogenic activity and vascularization using a bioactive vitroceramic in comparison to deproteinized bovine bone associated or not with autogenous bone graft.

DESIGN

Forty five male adult New Zealand rabbits, 5 months of age, mean weight of 4 Kg, underwent bilateral sinus augmentation surgeries to be divided in five groups: G - (Control) particulate autogenous bone graft (AG), BO - deproteinized bovine bone, BO+G - deproteinized bovine bone + AG, BSi -vitroceramic, and BSi + G - vitroceramic +AG. After 15, 45 and 90 days, all animals were euthanized for specimen's removal to be analyzed under light microscopy, histomorphometry, and immunohistochemistry for Runx2 and VEGF labeling.

RESULTS

G, BO and BO+G groups healed uneventfully, allowing the formation of mature remodeling bone at day 90, regarding the association of AG with the biomaterial. On the other hand, BSi and BSi + G groups showed an important cellular reaction and granulation/fibrous tissue formation from the first to the last period of observation. Runx-2 and VEGF immunolabeling were coherent with this result. However, histomorphometry did not reveal significant differences considering new bone formation.

CONCLUSIONS

Reconstructed maxillary sinuses using Biosilicate® permitted satisfactory new bone formation in comparison to the deproteinized bovine bone and AG. However, the presence of granulation/fibrous tissue and inflammatory cells associated to the degrading biomaterial indicate that further studies should be careful performed considering the immunological aspect of this new biomaterial.

Histomorphometric study of rabbit's maxillary sinus augmentation with various graft materials

The purpose of this animal study is to evaluate, by histomorphometric analysis, bone regeneration in rabbit's maxillary sinuses with blood clots alone, Bio-Oss, β-tricalcium phosphate (β-TCP), and demineralized tooth dentin (DTD) grafting. Bilateral sinus augmentation procedures were performed in 18 adult male rabbits. Rectangular replaceable bony windows were made with a piezoelectric thin saw insert. In the group 1, blood clots were filled; group 2, anorganic bovine graft (Bio-Oss) was grafted; group 3, β-TCP was grafted; group 4, DTD was grafted, and covered by replaceable bony windows. Animals were sacrificed at 2, 4, and 8 weeks after surgical procedure. The augmented sinuses were evaluated by histomorphometric analysis using hematoxylin and eosin and Masson's trichrome stains. Histologically, new bone formation was revealed along the elevated sinus membrane and all graft materials. The new bone area of the group 2 was significantly greater than the group 1, and of the group 3 was significantly greater than the group 2, and of the group 4 was significantly greater than the group 3 at 8 weeks with P<0.05. The bone marrow area of group 1 was significantly greater than other groups at 8 weeks. The DTD area was significantly lesser than Bio-Oss or β-TCP particles area at 8 weeks. This present study suggests that DTD can be effective graft materials for bone regeneration of the maxillary sinus augmentation.

A prospective controlled trial comparing xenograft/autogenous bone and collagen-stabilized xenograft for maxillary sinus augmentation-Complications, patient-reported outcomes and volumetric analysis

OBJECTIVE

Compare maxillary sinus augmentation (MSA) using two different materials-anorganic bovine bone mineral (ABBM) + autogenous bone (AB) (control group) vs. collagen-stabilized ABBM (test group) in terms of complications, patient-reported outcome measures (PROMs) and volumetric analysis.

MATERIALS AND METHODS

Sixty patients underwent sinus augmentation (30 control + 30 test group). Intra- and postoperative complications were recorded. PROMs measured the impact of grafting on daily activities, pain and morbidity. CT scans were used to measure graft volume, ridge height, material selection and degree of contact of graft-to-surrounding sinus walls. Dental implant placement parameters were also recorded.

RESULTS

All complications were minor and did not prevent completion of the augmentation or subsequent implant placement. Schneiderian membrane perforation was the most frequently encountered complication. Both treatment groups reported moderate limitation in the 1st 48 hr post-surgery but little or none by day 3 or 4. Jaw opening, chewing and bruising were significantly higher in the control group. The impact on work and social life was moderate initially but reduced to little or none by the 2nd day. Mild to moderate pain and interference to daily activities were reported for the first 3 days requiring the use of NSAIDs only. A mean graft volume of 1.46 cm³ (±0.77) was calculated in the control group and 1.27 cm³ (±0.65) in the test group. Extent of contact between graft and surrounding sinus walls had a significant impact on bone volume. Shorter (8 mm) implants were utilized more frequently in the test group, which was also more likely to require additional vertical augmentation, but this was not statistically significant.

CONCLUSION

MSA using a lateral wall approach is safe and associated with mild to moderate pain and restrictions to daily activities for 48-72 hr. Patients' reports of morbidity were greater with autogenous bone harvesting. Collagen-stabilized ABBM provides comparable bone volume to AB + ABBM that is sufficient for placement of implants of adequate size with no need for further vertical augmentation. Engaging the surrounding sinus walls had a significant positive impact on graft volume.

Histomorphometric analyses of area fraction of different ratios of Bio-Oss® and bone prior to grafting procedures - An in vitro study to demonstrate a baseline

OBJECTIVE

The objective of this study was to estimate the area fraction of different ratios of Bio-Oss^® and bone, prior to grafting in an in vitro model to demonstrate a histomorphometric baseline.

METHODS

Bio-Oss^® particles were mixed with autogenous bone from pig jaw in three different ratios (50:50, 80:20 and 100:0) and packed in rice paper in a standardized procedure. Histomorphometric analyses were performed in 25 specimens and 74 regions of interest. The area percentage of Bio-Oss^® , bone, and non-mineralized tissue (NMT) were calculated. Results were reported as mean values and 95% confidence interval (CI).

RESULTS

The mean area fraction of Bio-Oss^® was 20.6% (CI: 18.2-23) in the 50:50 mixture, 33.6% (CI: 29.7-37.6) in the 80:20 mixture, and 43.4% (CI: 40.5-46.3) in the 100:0 mixture. The mean area fraction of NMT was 60.5% (CI: 57.9-63.1) in the 50:50 mixture, 59.6% (CI: 56.4-62.7) in the 80:20 mixture, and 56.6% (CI: 53.7-59.5) in the 100:0 mixture. The mean area fraction of bone was 18.9% (CI: 16.9-20.9) in the 50:50 mixture and 6.8% (CI: 5-8.6) in the 80:20 mixture.

CONCLUSION

There is a great difference in the clinically estimated percentage and the histomorphometrically evaluated percentage of Bio-Oss^® at baseline, prior to grafting. The area fraction of different tissues presented in this study may be beneficial as guidance for histomorphometrical baseline calculations when different mixtures of Bio-Oss^® and autogenous bone are used as grafting materials.

Histopathological comparison of healing after maxillary sinus augmentation using xenograft mixed with autogenous bone versus allograft mixed with autogenous bone

OBJECTIVE

To compare the clinical and histologic outcomes of two different grafting materials (allograft and xenograft) when combined with autogenous bone and covered with a collagen membrane for sinus augmentation.

MATERIAL AND METHODS

A parallel case series of fourteen patients in need of a unilateral sinus augmentation was evaluated in this study. Seven patients received a graft composed by autologous cortical bone (ACB) and anorganic bovine bone in a ratio of 1:1; the other seven patients received ACB mixed with an allograft in the same ratio. Bone biopsies were obtained 6 months after sinus augmentation at the time of implant placement. Comparative histomorphometrical, histopathological, and immunohistochemical analyses were conducted and statistically analyzed.

RESULTS

After 12 months of functional loading, all implants in both groups were clinical and radiographically successful. Histomorphometrically, although the initial bone formation was not significantly different between groups (new mineralized tissue: 41.03(12.87)% vs. 34.50(13.18)%, p = .620; allograft vs. xenograft groups), the graft resorbed faster in the allograft group (remnant graft particles: 9.83[7.77]% vs. 21.71[17.88]%; p = .026; allograft vs. xenograft groups). Non-mineralized tissue did not statistically differ either (49.00[14.32]% vs. 43.79[19.90]%; p = .710; allograft vs. xenograft groups). The histologic analyses revealed higher cellular content, four times more osteoid lines, and higher vascularization in the xenograft group. Musashi-1 (mesenchymal stromal cell marker) was also more intensively expressed in the xenograft group (p = .019).

CONCLUSIONS

Both composite grafts generate adequate substratum to receive dental implants after healing. Compared with the xenograft composite, allograft composite shows faster turnover and a quicker decrease in biological action after 6 months.

Could Calcified Triglyceride Bone Cement Be an Alternative Graft Material in Maxillary Sinus Augmentation?

The ideal graft material for maxillary sinus augmentation is still a matter of controversy and the search for a more appropriate bone substitute for use continues. The aim of this study was to evaluate bone formation as a sign of the regeneration following maxillary sinus augmentation in rabbits using 3 different biomaterials, one of which is a newly developed graft material; calcified triglyceride bone cement (CTBC).Twenty-one New Zealand rabbits were used and randomly divided into 3 groups. Bilateral maxillary sinus augmentation was carried out and autogenous bone (AB), bovine hydroxyapatite (BHA), and CTBC were administered. Maxillary sinuses were dissected after fourth and eighth weeks of the operation. The bone formation was evaluated by stereological and histopathological analysis and the data were analyzed statistically.When the volume of primary bone is compared, statistically significant differences were found among all groups at both of the fourth and eighth weeks. The highest value was obtained from AB applied group. In BHA and CTBC applied groups, active bone formation, osseointegration of graft materials were observed at both fourth and eighth weeks. In CTBC applied group, primary bone formation was only seen as linked to the continuation of parent sinus bony wall.The efficiency of primary bone formation of CTBC was found less than AB and BHA. Of the 3 graft materials tested, BHA is the strongest alternative to AB graft for maxillary sinus augmentation.

Comparison of Two Xenograft Materials Used in Sinus Lift Procedures: Material Characterization and In Vivo Behavior

Detailed information about graft material characteristic is crucial to evaluate their clinical outcomes. The present study evaluates the physico-chemical characteristics of two xenografts manufactured on an industrial scale deproteinized at different temperatures (non-sintered and sintered) in accordance with a protocol previously used in sinus lift procedures. It compares how the physico-chemical properties influence the material’s performance in vivo by a histomorphometric study in retrieved bone biopsies following maxillary sinus augmentation in 10 clinical cases. An X-ray diffraction analysis revealed the typical structure of hydroxyapatite (HA) for both materials. Both xenografts were porous and exhibited intraparticle pores. Strong differences were observed in terms of porosity, crystallinity, and calcium/phosphate. Histomorphometric measurements on the bone biopsies showed statistically significant differences. The physic-chemical assessment of both xenografts, made in accordance with the protocol developed on an industrial scale, confirmed that these products present excellent biocompatibilitity, with similar characteristics to natural bone. The sintered HA xenografts exhibited greater osteoconductivity, but were not completely resorbable (30.80 ± 0.88% residual material). The non-sintered HA xenografts induced about 25.92 ± 1.61% of new bone and a high level of degradation after six months of implantation. Differences in the physico-chemical characteristics found between the two HA xenografts determined a different behavior for this material.

SEM-EDX Study of the Degradation Process of Two Xenograft Materials Used in Sinus Lift Procedures

Some studies have demonstrated that in vivo degradation processes are influenced by the material’s physico-chemical properties. The present study compares two hydroxyapatites manufactured on an industrial scale, deproteinized at low and high temperatures, and how physico-chemical properties can influence the mineral degradation process of material performance in bone biopsies retrieved six months after maxillary sinus augmentation. Residual biomaterial particles were examined by field scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) to determine the composition and degree of degradation of the bone graft substitute material. According to the EDX analysis, the Ca/P ratio significantly lowered in the residual biomaterial (1.08 ± 0.32) compared to the initial composition (2.22 ± 0.08) for the low-temperature sintered group, which also presented high porosity, low crystallinity, low density, a large surface area, poor stability, and a high resorption rate compared to the high-temperature sintered material. This demonstrates that variations in the physico-chemical properties of bone substitute material clearly influence the degradation process. Further studies are needed to determine whether the resorption of deproteinized bone particles proceeds slowly enough to allow sufficient time for bone maturation to occur.

The performance of CPC/PLGA and Bio-Oss® for bone regeneration in healthy and osteoporotic rats

The current study aimed to evaluate the biological performance of calcium phosphate cement (CPC) with polylactic-co-glycolic acid (PLGA) micro-particles and Bio-Oss^® in ovariectomized and healthy rats. Thirty-two Wistar rats received alternating experimental CPC/PLGA and Bio-Oss^® in femoral condyle defects in both femurs 6 weeks after ovariectomy (OVX, n = 16) or sham operation (SHAM, n = 16). Six weeks after OVX or SHAM surgery, bone morphology was analyzed by in vivo computed tomography (CT) to confirm osteoporotic bone condition. Analysis of bone formation and material remnants at 4 and 12 weeks after material implantation was performed by micro-CT, descriptive histology, histomorphometry and bone dynamics by fluorochrome labeling. The in vivo CT scans showed effective induction of osteoporotic bone condition by ovariectomy. Our data showed CPC/PLGA degraded relatively faster and more steadily. However, Bio-Oss^® had significantly less material remnants and showed significantly more bone formation compared to CPC/PLGA. Overall, our data showed relatively high amounts of CPC/PLGA for each time point, hampering new bone formation within the defect area. Osteoporotic conditions proved to significantly affect degradation rates, but did not significantly influence bone formation. An osteoporotic bone condition affects degradation of CPC/PLGA, which is vital information for its potential use in osteoporotic conditions. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 131-142, 2018.

Novel Resorbable and Osteoconductive Calcium Silicophosphate Scaffold Induced Bone Formation

This aim of this research was to develop a novel ceramic scaffold to evaluate the response of bone after ceramic implantation in New Zealand (NZ) rabbits. Ceramics were prepared by the polymer replication method and inserted into NZ rabbits. Macroporous scaffolds with interconnected round-shaped pores (0.5–1.5 mm = were prepared). The scaffold acted as a physical support where cells with osteoblastic capability were found to migrate, develop processes, and newly immature and mature bone tissue colonized on the surface (initially) and in the material’s interior. The new ceramic induced about 62.18% ± 2.28% of new bone and almost complete degradation after six healing months. An elemental analysis showed that the gradual diffusion of Ca and Si ions from scaffolds into newly formed bone formed part of the biomaterial’s resorption process. Histological and radiological studies demonstrated that this porous ceramic scaffold showed biocompatibility and excellent osteointegration and osteoinductive capacity, with no interposition of fibrous tissue between the implanted material and the hematopoietic bone marrow interphase, nor any immune response after six months of implantation. No histological changes were observed in the various organs studied (para-aortic lymph nodes, liver, kidney and lung) as a result of degradation products being released.

Clinical, Radiographic, and Histologic Evaluation of Maxillary Sinus Lift Procedure Using a Highly Purified Xenogenic Graft (Laddec(®))

OBJECTIVES

The aim of this study was to evaluate the clinical, radiographic and histologic results when a highly purified xenogenic bone (Laddec(®)) was used as grafting material in maxillary sinuses.

MATERIAL AND METHODS

In fifteen patients requiring unilateral maxillary sinus augmentation, the grafting procedure was performed with Laddec(®). Forty-two implants were installed after a 6 month healing period. The height of the augmented sinus was measured radiographically immediately after augmentation and postoperatively up to 36 months. At the time of implant placement, a bone core was harvested in each patient for histological examination.

RESULTS

The cumulative implant survival rate was 97.6%. The original height was 3.65 (SD 0.7) mm and the augmented sinus height was 13.8 (SD 1.4) mm after the surgery. The reduced height of grafted xenogenic material (RDL) at the implant insertion was 0.83 (SD 0.38) mm, and at the final postoperative visit was 0.91 (SD 0.25) mm, showing no significant correlation with the follow-up periods by Spearman's test (P = 0.118). In addition, no significant difference in the RDL was observed according to the site of implantation (P = 0.682). The mean implant marginal bone loss was 0.38 (SD 0.24) mm. Histological analysis showed the bone cores were composed of 64.72 (SD 3.44)% newly formed bone, 17.41 (SD 2.02)% connective tissue, 16.93 (SD 2.83)% residual graft particles, and 0.94 (SD 0.11)% inflammatory cells.

CONCLUSIONS

According to our data, the highly purified xenogenic bone (Laddec(®)), used as graft material in the sinus lift procedure, may create adequate bone volume, and appropriate osseointegration of dental implants.

Histological and micro-computed tomographic observations after maxillary sinus augmentation with porous hydroxyapatite alloplasts: a clinical case series

Background

It is important to visualize the phenomenon which occurs in actual clinical cases to decide the timing of implant placement subsequently after sinus graft. Although several clinical cases of bone augmentation using xenograft have been evaluated, the number of those reports which have described bone remodeling by alloplasty are not sufficient.

Findings

In the present report, to investigate bone remodeling histologically after maxillary sinus augmentation with porous hydroxyapatite alloplast, bone cores from the sinus floor of three female nonsmoking patients (aged 64–73 years) were collected 6 months after sinus lift surgery, embedded in methyl methacrylate resin, and prepared by conventional methods. Bone architecture and graft residues were evaluated by micro-computed tomography of the same specimens. Hematoxylin–eosin and Villanueva–Goldner staining revealed mature osteoblasts and multinucleated osteoclasts on the grafted sinus floor and surface of residual hydroxyapatite particles. The particulate interspace was partially filled with osteoid and calcified tissue and showed active vascularization.

Conclusion

The results suggested that bone regeneration and angiogenesis within and between porous hydroxyapatite particles were sufficiently found after 6 month histologically in the grafted sinus floor.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-1885-2) contains supplementary material, which is available to authorized users.

Experimental maxillary sinus augmentation using a highly bioactive glass ceramic

Physicochemical characteristics of a biomaterial directly influence its biological behavior and fate. However, anatomical and physiological particularities of the recipient site also seem to contribute with this process. The present study aimed to evaluate bone healing of maxillary sinus augmentation using a novel bioactive glass ceramic in comparison with a bovine hydroxyapatite. Bilateral sinus augmentation was performed in adult male rabbits, divided into 4 groups according to the biomaterial used: BO-particulate bovine HA Bio-Oss(®) (BO), BO+G-particulate bovine HA + particulate autogenous bone graft (G), BS-particulate glass ceramic (180-212 μm) Biosilicate(®) (BS), and BS+G-particulate glass ceramic + G. After 45 and 90 days, animals were euthanized and the specimens prepared to be analyzed under light and polarized microscopy, immunohistochemistry, scanning electron microscopy (SEM), and micro-computed tomography (μCT). Results revealed different degradation pattern between both biomaterials, despite the association with bone graft. BS caused a more intense chronic inflammation with foreign body reaction, which led to a difficulty in bone formation. Besides this evidence, SEM and μCT confirmed direct contact between newly formed bone and biomaterial, along with osteopontin and osteocalcin immunolabeling. Bone matrix mineralization was late in BS group but became similar to BO at day 90. These results clearly indicate that further studies about Biosilicate(®) are necessary to identify the factors that resulted in an unfavorable healing response when used in maxillary sinus augmentation.

A histomorphometric assessment of collagen-stabilized anorganic bovine bone mineral in maxillary sinus augmentation - a prospective clinical trial

OBJECTIVE

To histomorphometrically compare the use of collagen-stabilized anorganic bovine bone (ABBM-C) (test) to anorganic bovine bone + autogenous bone (ABBM + AB) (control) in maxillary sinus augmentation.

MATERIALS AND METHODS

Forty (n = 40 sinuses) patients underwent sinus augmentation and received either control (20 sinuses) or test bone graft (20 sinuses). Bone samples were harvested from the augmented sinuses 5 months postgrafting. The samples were processed for histomorphometry, which assessed within the primary region of interest (ROI-1), the area fraction of new bone (%NB), graft particle osseointegration (% OI), residual graft (%RG), and soft tissue components (% STM). The same analysis was also carried out in a second region of interest (ROI-2) located in a zone 1 mm proximal to the previous maxillary sinus floor.

RESULTS

In both ROI-1 and ROI-2, the mean % NB, %RG, and %STM in the control group were similar to mean values in the test group. The % OI was significantly greater in the control group (42.0 +/- 26.8) when compared to the test group (19.6 +/- 27.3) in ROI-2 (P < 0.05). No statistically significant differences were seen when ROI-1 and ROI-2 were compared except for improved %OI in ROI-2 in the control group. The mean proportion of lamellar bone to woven bone in the control group (1.22 ± 1.48) was significantly greater than the test group (0.38 ± 0.29) (P < 0.05).

CONCLUSION

ABBM-C exhibited very similar histomorphometric parameters to the composite graft of ABBM + AB. The ABBM + AB group was more mature as indicated by the significantly greater proportion of lamellar bone when compared to the ABBM-C. Improved % OI was seen in the zone proximal to the resident bony floor in the ABBM + AB group. Based on histological assessment, ABBM-C is a suitable bone substitute for the purposes of maxillary sinus augmentation. Its clinical utility may be indicated in cases of sinus membrane perforation and insufficient autogenous bone in the local area.

Retracted: In vivo behavior of hydroxyapatite/β‐TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days

Retraction: Maté Sánchez de Val JE , Calvo Guirado JL , Ramírez Fernández MP , Delgado Ruiz RA , Mazón P, De Aza PN . In vivo behavior of hydroxyapatite/β‐TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days. Clin Oral Impl Res . The above article, published online on August 7, 2015, in Wiley Online Library (wileyonlinelibrary.com) has been retracted by agreement between the journal editor‐in‐chief, L Heitz‐Mayfield, and John Wiley & Sons Ltd. The retraction has been agreed due to image discrepancies resulting in unreliable data. It has not been possible to prove the validity of the images. Images in Figure 4 have been used in other publications representing different time points and materials. Images within Figure 4 have been manipulated to represent different time points and materials. Reference Maté Sánchez de Val JE , Calvo Guirado JL , Ramírez Fernández MP , Delgado Ruiz RA , Mazón P, De Aza PN . In vivo behavior of hydroxyapatite/β‐TCP /collagen scaffold in animal model. Histological, histomorphometrical, radiological, and SEM analysis at 15, 30, and 60 days. Clin Oral Impl Res . https://doi.org/10.1111/clr.12656

A histomorphometric assessment of collagen-stabilized anorganic bovine bone mineral in maxillary sinus augmentation - a randomized controlled trial in sheep

OBJECTIVE

To histomorphometrically compare the use of collagen-stabilized anorganic bovine bone (ABBM-C) (test) to anorganic bovine bone + autogenous bone (ABBM + AB) (control) in maxillary sinus augmentation.

MATERIALS AND METHODS

Nine sheep underwent bilateral sinus augmentation. Each sinus was randomized to receive either control or test bone graft. Three animals were sacrificed at 8 weeks, and six animals were sacrificed at 16 weeks post-grafting. The 18 sinuses were processed for histomorphometry, which assessed the area fraction of new bone (%NB), residual graft (%RG) and soft tissue components (% STM), as well as graft particle osseointegration (% OI), within three zones equally distributed from the augmented sinus floor.

RESULTS

At week 16, a significant increase in %NB was evident across all three zones in the control group when compared to week 8. A significantly greater %NB was evident in the control group when compared to the test group in zones 2 (P < 0.001) and 3 (P < 0.001). There was a significant increase in %OI in week 16 when compared to week 8 across all three zones in the control group (P < 0.001). %OI in the control group was significantly greater across all three zones when compared to the test group at week 16 (P < 0.001). Zone was found to be a significant main effect (P < 0.001) that was independent of time and treatment with decreasing %OI in distant zones. %RG did not significantly change with time for both groups. There was a significant reduction in %ST in week 16 when compared to week 8 across all three zones in the control group (P < 0.001). %ST in the test group was significantly greater across all zones when compared to the control group at week 16 (P < 0.001).

CONCLUSION

Both groups exhibited very similar histomorphometric measurements in the zones proximal to the resident sinus wall. The % NB and % OI were greatest in the zones proximal to resident bony walls and gradually decreased as the distance from the proximal walls increased. There was greater % NB and % OI in the control group when compared to the test group in the distant zone.

Different bone regeneration patterns in periimplant circumferential gap defects grafted with two types of osteoconductive biomaterial

This study aimed to determine healing patterns in periimplant gap defect grafted with demineralized bovine bone mineral (DBBM) and porous titanium granules (PTG), which are known to induce a minimal tissue reaction and to undergo minimal biodegradation in healing process. Experiments were performed using a standardized periimplant gap-defect model in dogs with two observational periods: 4 and 8 weeks. Circumferential defects were surgically induced around dental implants on unilateral mandibles in five dogs, and collagen barrier membranes were placed over the DBBM and PTG grafts at two experimental sites and over a nongrafted site. Four weeks later, the same procedures were performed on the contralateral mandible, and the animals allowed to heal for a further 4 weeks, after which they were sacrificed and their mandibles with graft/control sites harvested for histologic evaluation. Both types of grafted biomaterials significantly enhanced the defect fill with newly formed bone, but the bone-to-implant contact (BIC) was significantly increased only at sites that had been grafted with DBBM. The two experimental sites exhibited different healing patterns, with new bone formation being observed on the surface of the DBBM particles throughout the defect, while there was no de novo bone formation on the PTG surface, but rather appositional bone growth from the base and lateral walls of the defect. It has been suggested that gap-defect filling with DBBM around dental implants may enhance both BIC and defect fill; however, the present findings show that defect grafting with PTG enhances only defect fill and not BIC. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1202-1209, 2016.

Dental Stem Cell Migration on Pulp Ceiling Cavities Filled with MTA, Dentin Chips, or Bio-Oss

MTA, Bio-Oss, and dentin chips have been successfully used in endodontics. The aim of this study was to assess the adhesion and migration of dental stem cells on human pulp ceiling cavities filled with these endodontic materials in an experimental model, which mimics the clinical conditions of regenerative endodontics. Cavities were formed, by a homemade mold, on untouched third molars, filled with endodontic materials, and observed with electron microscopy. Cells were seeded on cavities' surface and their morphology and number were analysed. The phenomenon of tropism was assessed in a migration assay. All three materials demonstrated appropriate microstructures for cell attachment. Cells grew on all reagents, but they showed a differential morphology. Moreover, variations were observed when comparing cells numbers on cavity's filling versus the surrounding dentine disc. The highest number of cells was recorded on dentin chips whereas the opposite was true for Bio-Oss. This was confirmed in the migration assay where a statistically significant lower number of cells migrated towards Bio-Oss as compared to MTA and dentin chips. This study highlights that MTA and dentin chips have a greater potential compared to Bio-Oss regarding the attraction of dental stem cells and are good candidates for bioengineered pulp regeneration.

Bone regeneration and gene expression in bone defects under healthy and osteoporotic bone conditions using two commercially available bone graft substitutes

Biosilicate(®) and Bio-Oss(®) are two commercially available bone substitutes, however, little is known regarding their efficacy in osteoporotic conditions. The purpose of this study was to evaluate the osteogenic properties of both materials, at tissue and molecular level. Thirty-six Wistar rats were submitted to ovariectomy (OVX) for inducing osteoporotic conditions and sham surgery (SHAM) as a control. Bone defects were created in both femurs, which were filled with Biosilicate(®) or Bio-Oss(®), and empty defects were used as control. For the healthy condition both Biosilicate(®) and Bio-Oss(®) did not improve bone formation after 4 weeks. Histomorphometric evaluation of osteoporotic bone defects with bone substitutes showed more bone formation, significant for Bio-Oss(®). Molecular biological evaluation was performed by gene-expression analysis (Runx-2, ALP, OC, OPG, RANKL). The relative gene expression was increased with Biosilicate(®) for all genes in OVX rats and for Runx-2, ALP, OC and RANKL in SHAM rats. In contrast, with Bio-Oss(®), the relative gene expression of OVX rats was similar for all three groups. For SHAM rats it was increased for Runx-2, ALP, OC and RANKL. Since both materials improved bone regeneration in osteoporotic conditions, our results suggest that bone defects in osteoporotic conditions can be efficiently treated with these two bone substitutes.

In vivo bone formation by human alveolar-bone-derived mesenchymal stem cells obtained during implant osteotomy using biphasic calcium phosphate ceramics or Bio-Oss as carriers

OBJECTIVES

The aim of this study was to evaluate HA coated with different ratios of TCP as a carrier for hABMSCs obtained during implant osteotomy in comparison to slowly-resorbing biomaterial, Bio-Oss, as a negative control, using in vitro and in vivo experiments.

MATERIALS AND METHODS

Human ABMSCs (hABMSCs) harvested during implant osteotomy were transplanted using HA/TCP or Bio-Oss as carriers in a murine ectopic transplantation model (n = 12). Pore size and cell affinity were evaluated in vitro. The area of newly formed bone was analyzed histometrically, the number of osteocytes was counted, and immunohistochemical staining was conducted against several markers of osteogenesis, including alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX-2), osteocalcin (OCN), and osteopontin (OPN). Osteoclast formation was evaluated by tartrate-resistant acid phosphatase staining.

RESULTS

The carrier materials had comparable pore sizes. The cell affinity assay resulted in a high proportion of cell adhesion (>90%) in all experimental groups. Substantial new bone and osteocyte formation was observed on both HA/TCP carriers, whereas it was minimal with Bio-Oss. Positive immunostaining for ALP, RUNX-2, OCN, and OPN was observed with HA/TCP, but only limited expression of osteogenic markers with Bio-Oss. Conversely, there was a minimal osteoclast presence with Bio-Oss, but a significant presence of osteoclasts with both HA/TCP carriers.

CONCLUSIONS

Both types of scaffolds, BCP and Bio-Oss, showed high stem cell-carrying potential, but the in vivo healing patterns of their complexes with hABMSC could be affected by the microenvironment on the surfaces of the scaffolds.

Flapless alveolar ridge preservation utilizing the "socket-plug" technique: clinical technique and review of the literature

It has been documented that after every extraction of one or more teeth, the alveolar bone of the respective region undergoes resorption and atrophy. Therefore, ridge preservation techniques are often employed after tooth extraction to limit this phenomenon. The benefits of a flapless procedure include maintenance of the buccal keratinized gingiva, prevention of alterations to the gingival contours, and migration of the mucogingival junction that are often experienced after raising a flap. The purpose of this article is to review the literature concerning flapless ridge preservation techniques with the aid of collagen plugs for occlusion of the socket. The term "socket-plug" technique is introduced to describe these techniques. The basic steps of the "socket-plug" technique consist of atraumatic tooth extraction, placement of the appropriate biomaterials in the extraction site, preservation of soft tissue architecture employing a flapless technique, and placement and stabilization of the collagen plug. A case example is presented that illustrates the steps used in this technique.

Bone neo-formation and mineral degradation of 4Bone.(®) Part II: histological and histomorphometric analysis in critical size defects in rabbits

OBJECTIVE

To carry out the histological and histomorphometric plus radiological analysis of biphasic ceramic.

MATERIALS AND METHOD

In this study, porous HA/βTCP (4Bone(®) ) ceramic material was tested for the bone repairing capacity and osteoinductive potential in a New Zealand rabbit model. The ratio of the ceramic's components HA/βTCP was 60/40 (in wt%).

RESULTS

The 4Bone(®) showed significantly more bone formation in the pores and in the periphery of the graft than the control group. Histomorphometric analysis revealed that the ceramic material (66.43% ± 0.29) produced higher values of bone-to-implant contact (BIC) percentages (higher quality, closer contact); moreover, defect closure was significative higher in relation with control group (64.15% ± 3.52).

CONCLUSIONS

4Bone(®) is a biocompatible, partially resorbable and osteoconductive grafting material. Biphasic graft material of HA/βTCP with a porosity of 95% without loading favors new bone formation.

Comparison of tissue-engineered bone from different stem cell sources for maxillary sinus floor augmentation: a study in a canine model

PURPOSE

To compare the potential of tissue-engineered bone derived from different stem cell sources for canine maxillary sinus augmentation.

MATERIALS AND METHODS

Bilateral maxillary sinus floor augmentations were performed in 6 beagles and were randomly repaired with 3 graft types: Bio-Oss granules alone (n = 4; group A), a complex of osteoblasts derived from bone marrow mesenchymal stem cells (BMMSCs) and Bio-Oss (n = 4; group B), and a complex of osteoblasts derived from periodontal ligament stem cells (PDLSCs) and Bio-Oss (n = 4; group C). After 12 weeks, fluorescent labeling, maxillofacial computed tomography, scanning electron microscopy, and histologic and histomorphometric analyses were used to evaluate new bone deposition, mineralization, and remodeling in the augmented area.

RESULTS

The osteogenic capacity was greater in groups B and C than in group A. The level tended to be higher in group C than in group B; however, the difference was not statistically significant.

CONCLUSIONS

Seeding of PDLSCs or BMMSCs onto Bio-Oss can promote bone formation and mineralization and maintain the maximum volume of the augmented maxillary sinus. These tissue-engineered bone complexes might be a good option for augmentation of the maxillary sinus in edentulous patients.