Histologic and Ultrastructural Analysis of Regenerated Bone in Maxillary Sinus Augmentation Using a Porcine Bone–Derived Biomaterial

Does defect configuration affect the outcomes of alveolar ridge preservation? An experimental in vivo study

PURPOSE

The purpose of this study was to compare the bone healing potential of 1-, 2-, and 3-wall defects following alveolar ridge preservation (ARP) treatment, as well as to evaluate the efficacy of ARP as a treatment option for destructive sites.

METHODS

Three groups, characterized by 1-, 2-, and 3-wall defects, were randomly assigned to the maxillary second, third, and fourth premolars in each of 8 beagle dogs. Each defect was created at either the mesial or distal root site of the tooth, which was hemi-sectioned and extracted. The contralateral root was preserved to superimpose with the experimental site for histomorphometric analysis. For each site, either spontaneous healing (SH; control) or ARP (test intervention) was randomly applied. Each group was divided in half and underwent a healing period of either 4 or 12 weeks. The Mann-Whitney U test and Kruskal-Wallis test were used for histomorphometric analyses. Statistical significance was set at P<0.05.

RESULTS

Qualitative analysis revealed a higher percentage of new bone in the apical area compared to the coronal area, regardless of defect type and healing period. In quantitative analysis, the 3-wall defect exhibited a significantly higher percentage of mineralization in the ARP group after 12 weeks of healing (ARP: 61.73%±7.52%; SH: 48.84%±3.06%; P=0.029). An increased percentage of mineralization was observed with a greater number of remaining bony walls, although this finding did not reach statistical significance.

CONCLUSIONS

Within the limitations of this study, ARP treatment for compromised sockets appears to yield a higher percentage of mineralization compared to SH. Although the effectiveness of the remaining bony walls was limited, their presence appeared to improve the percentage of mineralization in ARP treatment.

Maxillary Sinus Augmentation with Xenogenic Collagen-Retained Heterologous Cortico-Cancellous Bone: A 3-Year Follow-Up Randomized Controlled Trial

Sinus augmentation procedures have become a valuable solution for patients with posterior maxillary edentulism. The objective of this study was to explore the efficacy and safety of porcine xenograft with collagen supplementation as a potential alternative to autologous bone grafts in lateral sinus augmentation over a three-year follow-up period. Twelve patients, each with bilateral posterior maxillary edentulism, were enrolled and randomly allocated to receive either a porcine xenograft or an autologous graft. Comprehensive assessments, including clinical and radiographic evaluations, were conducted at specific intervals, including implant stability, marginal bone loss, prosthetic and biological complications, and patient preferences. The results demonstrated no significant differences between the two graft materials in terms of implant survival, marginal bone loss, and patient preferences after three years of follow-up. Only one implant was affected by peri-implantitis, and prosthesis-related complications were present in one patient possibly due to bruxism. In conclusion, these findings suggest that a porcine xenograft with collagen supplementation may be a viable alternative to an autograft in lateral sinus augmentation procedures. The high implant survival rate, minimal complications, and patient satisfaction indicate the potential clinical relevance of this graft material and should be further investigated to confirm these promising results.

Injectable Xenogeneic Dental Pulp Decellularized Extracellular Matrix Hydrogel Promotes Functional Dental Pulp Regeneration

The present challenge in dental pulp tissue engineering scaffold materials lies in the development of tissue-specific scaffolds that are conducive to an optimal regenerative microenvironment and capable of accommodating intricate root canal systems. This study utilized porcine dental pulp to derive the decellularized extracellular matrix (dECM) via appropriate decellularization protocols. The resultant dECM was dissolved in an acid pepsin solution to form dECM hydrogels. The analysis encompassed evaluating the microstructure and rheological properties of dECM hydrogels and evaluated their biological properties, including in vitro cell viability, proliferation, migration, tube formation, odontogenic, and neurogenic differentiation. Gelatin methacrylate (GelMA) hydrogel served as the control. Subsequently, hydrogels were injected into treated dentin matrix tubes and transplanted subcutaneously into nude mice to regenerate dental pulp tissue in vivo. The results showed that dECM hydrogels exhibited exceptional injectability and responsiveness to physiological temperature. It supported the survival, odontogenic, and neurogenic differentiation of dental pulp stem cells in a 3D culture setting. Moreover, it exhibited a superior ability to promote cell migration and angiogenesis compared to GelMA hydrogel in vitro. Additionally, the dECM hydrogel demonstrated the capability to regenerate pulp-like tissue with abundant blood vessels and a fully formed odontoblast-like cell layer in vivo. These findings highlight the potential of porcine dental pulp dECM hydrogel as a specialized scaffold material for dental pulp regeneration.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

A Narrative Review on the Effectiveness of Bone Regeneration Procedures with OsteoBiol® Collagenated Porcine Grafts: The Translational Research Experience over 20 Years

Over the years, several bone regeneration procedures have been proposed using natural (autografts, allografts, and xenografts) and synthetic (i.e., metals, ceramics, and polymers) bone grafts. In particular, numerous in vitro and human and animal in vivo studies have been focused on the discovery of innovative and suitable biomaterials for oral and maxillofacial applications in the treatment of severely atrophied jaws. On this basis, the main objective of the present narrative review was to investigate the efficacy of innovative collagenated porcine bone grafts (OsteoBiol^®, Tecnoss^®, Giaveno, Italy), designed to be as similar as possible to the autologous bone, in several bone regeneration procedures. The scientific publications were screened by means of electronic databases, such as PubMed, Scopus, and Embase, finally selecting only papers that dealt with bone substitutes and scaffolds for bone and soft tissue regeneration. A total of 201 papers have been detected, including in vitro, in vivo, and clinical studies. The effectiveness of over 20 years of translational research demonstrated that these specific porcine bone substitutes are safe and able to improve the biological response and the predictability of the regenerative protocols for the treatment of alveolar and maxillofacial defects.

Characterization of Dental Pulp Stem Cells Response to Bone Substitutes Biomaterials in Dentistry

Bone substitute biomaterials (BSBs) represent a promising alternative to bone autografts, due to their biocompatibility, osteoconduction, slow resorption rates, and the ability to define and maintain volume for bone gain in dentistry. Many biomaterials are tailored to provide structural and biological support for bone regeneration, and allow the migration of bone-forming cells into the bone defect. Neural crest-derived stem cells isolated from human dental pulp (hDPSCs) represent a suitable stem cell source to study the biological effects of BSBs on osteoprogenitor cells involved in the physiological bone regenerative processes. This study aimed to evaluate how three different BSBs affect the stem cell properties, osteogenic differentiation, and inflammatory properties of hDPSCs. Our data highlight that BSBs do not alter cell proliferation and stemness markers expression, nor induce any inflammatory responses. Bone metabolism data show that hDPSCs exposed to the three BSBs distinctively secrete the factors supporting osteoblast activity and osteoclast activity. Our data indicate that (i) hDPSCs are a suitable stem cell source to study the effects of BSBs, and that (ii) the formulation of BSBs may condition the biological properties of stem cells, suggesting their versatile suitability to different dentistry applications.

Maxillary sinus floor augmentation comparing bovine versus porcine bone xenografts mixed with autogenous bone graft. A split-mouth randomized controlled trial

Aim

To compare the effectiveness of two xenografts for maxillary sinus floor augmentation in terms of clinical, radiographical, histologic, and molecular outcomes.

Materials and methods

A split‐mouth randomized clinical trial was conducted at the University of Granada. Ten consecutive patients in need of bilateral two‐staged maxillary sinus floor augmentation were included. Each patient received both biomaterials (porcine bone mineral and anorganic bovine bone), which were randomly assigned for bilateral sinus augmentation. The maxillary autogenous bone scraped from the sinus access window was mixed with each xenograft at a 20:80 ratio. After a healing period of 6 months, bone biopsies were collected with a trephine during the implant placement in the regenerated area. Histologic, histomorphometrical, immunohistochemical, and molecular outcomes were analyzed. Clinical and radiographical data throughout the treatment phases were also evaluated.

Results

The resulting anatomic features were similar between both groups. After six months of graft consolidation, the graft resorption rates were similar between both biomaterials. The histologic, histomorphometrical, and immunohistochemical results showed no statistical differences between groups.

Conclusion

Anorganic bovine bone and porcine bone mineral combined with maxillary autogenous cortical bone show similar biologic and radiologic features in terms of biomaterial resorption, osteoconduction, and osteogenesis when used for maxillary sinus floor augmentation.

Advances in biomaterial production from animal derived waste

Animal derived waste, if not disposed properly, could pose a threat to the environment and its inhabitants. Recent advancements in biotechnological and biomedical interventions have enabled us to bioengineer these valuable waste substrates into biomaterials with diversified applications. Rearing and processing of poultry, cattle, sheep, goat, pig, and slaughterhouse waste can aid in effective waste valorization for the fabrication of biopolymers, composites, heart valves, collagen, scaffolds, pigments and lipids, among other industrially important biomaterials. Feathers and eggshell waste from the poultry industry can be used for producing keratinous proteins and biocomposites, respectively. Cattle dung, hoofs and cattle hide can be used for producing hydroxyapatite for developing scaffolds and drug delivery systems. Porcine derived collagen can be used for developing skin grafts, while porcine urinary bladder has antiangiogenic, neurotrophic, tumor-suppressive and wound healing properties. Sheep teeth can be used for the production of low-cost hydroxyapatite while goat tissue is still underutilized and requires more in-depth investigation. However, hydrolyzed tannery fleshings show promising potential for antioxidant rich animal feed production. In this review, the recent developments in the production and application of biomaterials from animal waste have been critically analyzed. Standardized protocols for biomaterial synthesis on a pilot scale, and government policy framework for establishing an animal waste supply chain for end users seem to be lacking and require urgent attention. Moreover, circular bioeconomy concepts for animal derived biomaterial production need to be developed for creating a sustainable system.

Advantages of Porcine Xenograft over Autograft in Sinus Lift: A Randomised Clinical Trial

This study aimed to compare the performance of intra-oral autologous bone grafts versus porcine xenografts in a two-step lateral window sinus lift. This split-mouth randomised controlled trial sequentially enrolled 12 patients with a 6-month follow-up. For each patient, a simultaneous randomised bilateral maxillary sinus lift was performed and filled with autologous bone from the mandible (control) or a porcine xenograft (test). A bone biopsy sample was collected during the implant placement for histological and histomorphometric analysis. CT scans were performed at the beginning and at the end of the trial to assess radiological evolution. A comparison of initial and six-month CT scans indicated statistically significant increases in bone level for both materials (7.8 ± 2.4 mm for autologous and 8.7 ± 2.2 mm for xenograft, p < 0.05), and there were no significant differences between the performance of the two materials over time (p = 0.26). The histological analysis showed various stages of the remodelling process and no cells or other signs of inflammation or infection were visible in both groups. The porcine xenografts presented similar results for the studied variables when compared to autologous bone, being a reasonable alternative for a sinus lift.

Long-term stability of adjunctive use of enamel matrix protein derivative on porcine-derived xenograft for the treatment of one-wall intrabony defects: A 4-year extended follow-up of a randomized controlled trial

Background

The long‐term outcomes of demineralized porcine bone matrix (DPBM) in combination with enamel matrix protein derivative (EMD) for the treatment of one‐wall intrabony defects have not yet been evaluated. Therefore, this study aimed to assess the clinical, radiographic, and patient‐reported outcomes of regenerative therapy using DPBM with EMD (test group) in comparison with DPBM alone (control group) for the treatment of one‐wall intrabony defects in the molar regions.

Methods

Thirty‐four patients (control group, n = 18, and test group, n = 16) were available at the 4‐year follow‐up assessment. Clinical (probing pocket depth and clinical attachment level [CAL]), radiographic (defect depth and width), and patient‐reported (Oral Health Impact Profile [OHIP]‐14) parameters were evaluated at baseline, 2 years, and 4 years after regenerative treatment.

Results

Both treatment modalities, with and without adjunctive use of EMD, resulted in significant improvement of clinical (mean gain in CAL of 1.58 ± 1.34 mm), radiographic (mean defect width fill of 2.41 ± 0.90 mm), and oral health‐related quality of life outcomes at 2 years after regenerative treatment of one‐wall intrabony defects (P < 0.001), which has been sustained over a 4‐year follow‐up period. Particularly, OHIP‐14 scores revealed a statistically significant reduction in physical pain, psychological discomfort, and physical disability (P < 0.05).

Conclusions

The clinical, radiographic, and patient‐reported outcomes were significantly improved when DPBM was used in the regenerative treatment, but no additional benefits were observed with the adjunctive use of EMD.

Collagenated Porcine Heterologous Bone Grafts: Histomorphometric Evaluation of Bone Formation Using Different Physical Forms in a Rabbit Cancellous Bone Model

Collagenated porcine-derived bone graft materials exhibit osteoconductive properties and the development of different formulations intends to enhance bone regeneration. This study aims to evaluate bone healing in a rabbit cancellous bone defect in response to grafting with different physicochemical forms of heterologous porcine bone. Twenty-six adult male New Zealand White rabbits received two critical size femoral bone defects per animal (n = 52), each randomly assigned to one of the five tested materials (Apatos, Gen-Os, mp3, Putty, and Gel 40). Animals were sacrificed at 15- and 30-days post-surgery. Qualitative and quantitative (new bone, particle and connective tissue percentages) histological analyses were performed. Histomorphometry showed statistically significant differences in all evaluated parameters between mp3 and both Putty and Gel 40 groups, regardless of the timepoint (p < 0.05). Moreover, statistical differences were observed between Apatos and both Putty (p = 0.014) and Gel 40 (p = 0.007) groups, at 30 days, in regard to particle percentage. Within each group, regarding new bone formation, mp3 showed significant differences (p = 0.028) between 15 (40.93 ± 3.49%) and 30 (52.49 ± 11.04%) days. Additionally, intragroup analysis concerning the percentage of particles revealed a significant reduction in particle occupied area from 15 to 30 days in mp3 and Gen-Os groups (p = 0.009). All mp3, Gen-Os and Apatos exhibited promising results in terms of new bone formation, thus presenting suitable alternatives to be used in bone regeneration.

Core Ossification of Bone Morphogenetic Protein-2-Loaded Collagenated Bone Mineral in the Sinus

The objective of this study was to investigate in vitro release kinetics and ossification patterns of bone morphogenetic protein-2-soaked collagenated porcine bone mineral (BMP-2/CPBM) in rabbit sinuses. Release kinetics of BMP-2/CPBM was determined in vitro up to 56 days. In 16 rabbits, BMP-2/CPBM (BMP group) and CPBM alone (control group) were bilaterally grafted in both sinuses. After 4 (N = 8) and 12 (N = 8) weeks, radiographic and histologic analyses were performed. Approximately 40% of BMP-2 was released from CPBM during 3 days in vitro; release maintained at a reduced level until day 56. In vivo, new bone formation in BMP group was dominant at the center and decreased toward the borders of the sinus, while it mainly possessed close to the sinus membrane and basal bone in control group. At the center, significantly more new bone was found in BMP group compared to control group at 4 weeks (29.14% vs. 16.50%; p < 0.05). The total augmented volume of BMP group was significantly greater than control group at 4 (370.13 mm³ vs. 299.32 mm³) and 12 (400.40 mm³ vs. 290.10 mm³) weeks (p < 0.05). In conclusion, BMP-2/CPBM demonstrated a core ossification with a greater augmented volume and new bone formation in the center of the sinus compared to CPBM alone. Impact statement The center of the augmented maxillary sinus tends to show a slower and inferior new bone formation compared to the sites near the sinus membrane and basal bone. In this study, bone morphogenetic protein-2 (BMP-2) loaded onto collagenated porcine bone mineral (CPBM) resulted in a greater augmented volume and new bone formation at the center of the grafted sinus compared to CPBM alone. Therefore, BMP-2-added CPBM in maxillary sinus augmentation may potentially be beneficial to the clinicians, in terms of accelerating the new bone formation at the center area where the apical half of the implant fixture usually places.

Adjunctive use of enamel matrix derivatives to porcine-derived xenograft for the treatment of one-wall intrabony defects: Two-year longitudinal results of a randomized controlled clinical trial

Background

The purpose of this study was to evaluate the potential advantages of adjunctive use of enamel matrix protein derivative (EMD) in combination with demineralized porcine bone matrix (DPBM) for the treatment of one‐wall intrabony defects in the molar regions, in comparison with the use of DPBM alone, through a randomized controlled clinical trial.

Methods

Forty‐two participants were randomly assigned to two groups: one where DPBM with the adjunctive use of EMD (test group, n = 20) was applied and the other without EMD (control group, n = 22). Changes in the clinical and radiographic parameters from baseline at 6, 12, and 24 months were measured (probing pocket depth, clinical attachment loss, defect depth, and defect width). Postoperative discomfort (severity/duration of pain and swelling) and early soft tissue wound healing (dehiscence/fenestration, persistent swelling, spontaneous bleeding, and ulceration) were also assessed.

Results

Both treatment modalities, with and without EMD, resulted in significant improvement of clinical and radiographic outcomes without any severe adverse events. However, no statistically significant differences in any of the measured parameters were found when the two groups were compared. Early wound healing outcomes and the severity of swelling did not differ between the groups, but the severity of pain (P = 0.046), duration (P = 0.033), and swelling (P = 0.022) were significantly lower in the test group.

Conclusions

DPBM has been verified for biocompatibility and can be used as a scaffold to enhance the clinical and radiographic outcomes of periodontal regeneration of one‐wall intrabony defects. In particular, the adjunctive use of EMD significantly reduced the postoperative discomfort.

Current Stage of Marine Ceramic Grafts for 3D Bone Tissue Regeneration

Bioceramic scaffolds are crucial in tissue engineering for bone regeneration. They usually provide hierarchical porosity, bioactivity, and mechanical support supplying osteoconductive properties and allowing for 3D cell culture. In the case of age-related diseases such as osteoarthritis and osteoporosis, or other bone alterations as alveolar bone resorption or spinal fractures, functional tissue recovery usually requires the use of grafts. These bone grafts or bone void fillers are usually based on porous calcium phosphate grains which, once disposed into the bone defect, act as scaffolds by incorporating, to their own porosity, the intergranular one. Despite their routine use in traumatology and dental applications, specific graft requirements such as osteoinductivity or balanced dissolution rate are still not completely fulfilled. Marine origin bioceramics research opens the possibility to find new sources of bone grafts given the wide diversity of marine materials still largely unexplored. The interest in this field has also been urged by the limitations of synthetic or mammalian-derived grafts already in use and broadly investigated. The present review covers the current stage of major marine origin bioceramic grafts for bone tissue regeneration and their promising properties. Both products already available on the market and those in preclinical phases are included. To understand their clear contribution to the field, the main clinical requirements and the current available biological-derived ceramic grafts with their advantages and limitations have been collected.

Effectiveness of Xenograft and Porcine-Derived Resorbable Membrane in Augmentation of Posterior Extraction Sockets with a Severe Wall Defect. A Radiographic/Tomographic Evaluation

Objectives

The aim of the present prospective study was to evaluate, by means of intraoral periapical radiographs and cone-beam computed tomography, hard tissue changes after ridge augmentation procedures in posterior extraction sockets with severe wall defects.

Material and Methods

Twenty patients, with a non-restorable premolar/molar tooth and severe wall defect, were enrolled in the present study, and underwent single-tooth extraction. Extraction sites were grafted with porcine-derived bone covered by porcine-derived collagen membrane. Intraoral periapical radiographs and cone-beam computed tomography scans, obtained at enrolment, and 6 months after ridge augmentation procedures were analysed and compared.

Results

In the intraoral periapical radiographs, mean vertical bone gains detected at the distal, central and mesial aspects of the extraction sockets were 3.5 (SD 1.1) mm, 8.2 (SD 2.1) mm, and 3.9 (SD 1.7) mm, respectively. In the cone-beam computed tomography scans, the mean vertical bone gains detected at the more vestibular and more palatal aspects were 4.4 (SD 1.9) mm, and 3.3 (SD 2.8) mm, respectively. The mean horizontal bone gain was 3.5 (SD 1.6) mm. In all examined defects, mean vertical and horizontal bone levels showed a statistically significant increase (P < 0.05) at 6 months after extraction.

Conclusions

Within the limits of this study, the results suggest that porcine-derived bone graft covered by a collagen membrane can support significant vertical and horizontal bone gain at posterior post-extraction sockets with severe wall defects.

Steam Sterilization of Equine Bone Block: Morphological and Collagen Analysis

Introduction

The use of equine bone blocks is widely reported for bone augmentation techniques. The block must be shaped according to the form of the defect that should be regenerated. The shaping could be performed by hand before or during the surgery, in a sterile ambient, or using a CNC milling machine that could not be sterile. The aim of our study was to evaluate if a steam sterilization could provide a medical grade sterilization of the blocks and to evaluate if bone microstructure and collagen structures change after different steam sterilization protocols provided by mainstream autoclave.

Materials and Method

Two blocks of equine bone were divided into 16 samples. 1 sample was used as control and not submitted to any treatment. 15 samples were infected with a Streptococcus faecalis bacterial culture. The samples were singularly packed, randomly divided into 3 groups, and submitted to autoclave sterilization on the same device. The groups were submitted to a sterilization cycle (Gr. A: 121°C, 1,16 bar for 20'; Gr. B:134°C, 2,16 bar for 4'; Gr. C: 134°C, 2,16 bar for 3.30 min.). 2 samples for each group were evaluated for the sterility. 3 samples for each group were observed at SEM to notice the macro- and microstructure modification and to confocal microscope to observe the collagen.

Results

All samples were sterile. The SEM evaluation showed, in all groups, a preserved morphological structure. Confocal microscope evaluation shows that the collagen structure appears to be more uniform and preserved in group C.

Conclusion

Data show that autoclave steam sterilization could be reliable to obtain sterilization of equine bone blocks.

Fluorination Enhances the Osteogenic Capacity of Porcine Hydroxyapatite

In a previous study, we successfully prepared fluorinated porcine hydroxyapatite (FPHA) by immersing porcine hydroxyapatite (PHA) in an aqueous solution of 0.25 M sodium fluoride (NaF) under thermal treatment, and the resulting FPHA showed better physicochemical and biological properties than PHA. The purpose of this study was to further investigate how fluorine incorporation influenced the biocompatibility and osteogenic capacity of PHA. The concentrations of Ca, P, F, and Mg ions in PHA and FPHA extracts were detected by inductively coupled plasma optical emission spectrometry. Rat bone marrow stromal cells (rBMSCs) were treated with PHA and FPHA extracts, and the effects of these extracts on cell proliferation and osteoblastic differentiation were evaluated via Cell Counting Kit-8 assay, alkaline phosphatase assay, and real time-quantitative polymerase chain reaction. For the in vivo assessment, PHA and FPHA were implanted into subcutaneous pockets (n = 6) and rat calvarial defects (diameter = 5 mm, n = 14) for 12 weeks to determine their biocompatibility and osteogenic capacity by using micro-computed tomography (CT) and histological analysis. FPHA extracts, which release higher concentrations of F and Mg ions, better promoted the osteoblastic differentiation of rBMSCs in vitro. The result of biocompatibility evaluation confirmed that the host response and chronic inflammation cells infiltration degree around PHA and FPHA granules were similar. Micro-CT and histological analysis showed newer mineralized bone formation in rats with FPHA-treated defects than in rats with PHA-treated defects. The results of in vitro and in vivo tests consistently indicate that fluorine incorporation effectively enhanced the osteogenic capacity of PHA.

Bone regeneration using a porcine bone substitute collagen composite in vitro and in vivo

The biocharacteristics of xenogeneic grafts make them a possible substitute for autogenous bone grafts in dental bone graft procedures. This study aimed to develop a novel porcine graft with collagen capable of generating new bone in bone defects via osteoconduction over 8 weeks of healing and to compare it with a porcine graft. The porcine collagen graft was made to undergo a cell viability test (MTT) and alkaline phosphatase assay (ALP). The surgical procedure was performed in 20 male adult New Zealand white rabbits. Four calvarial critical-size defects of 6 mm in diameter were prepared in each rabbit. The upper left defect was filled with a porcine graft of 500–1000 μm, the upper right with a porcine collagen graft, the lower left with hydroxyapatite/beta-tricalcium phosphate and the lower right served as the control without any filling material. The rabbits were divided and sacrificed at 2, 4, 6 and 8 weeks after surgery. Histological and micro-CT scan results showed that the performance of the porcine collagen graft is superior for regenerating new bone. Porcine collagen graft showed cell viability and osteoblast-like cell differentiation in vitro. The results indicate that porcine collagen graft is a potential bone substitute for clinical application.

Enhancement of Osteoblastic-Like Cell Activity by Glow Discharge Plasma Surface Modified Hydroxyapatite/β-Tricalcium Phosphate Bone Substitute

Glow discharge plasma (GDP) treatments of biomaterials, such as hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) composites, produce surfaces with fewer contaminants and may facilitate cell attachment and enhance bone regeneration. Thus, in this study we used argon glow discharge plasma (Ar-GDP) treatments to modify HA/β-TCP particle surfaces and investigated the physical and chemical properties of the resulting particles (HA/β-TCP + Ar-GDP). The HA/β-TCP particles were treated with GDP for 15 min in argon gas at room temperature under the following conditions: power: 80 W; frequency: 13.56 MHz; pressure: 100 mTorr. Scanning electron microscope (SEM) observations showed similar rough surfaces of HA/β-TCP + Ar-GDP HA/β-TCP particles, and energy dispersive spectrometry analyses showed that HA/β-TCP surfaces had more contaminants than HA/β-TCP + Ar-GDP surfaces. Ca/P mole ratios in HA/β-TCP and HA/β-TCP + Ar-GDP were 1.34 and 1.58, respectively. Both biomaterials presented maximal intensities of X-ray diffraction patterns at 27° with 600 a.u. At 25° and 40°, HA/β-TCP + Ar-GDP and HA/β-TCP particles had peaks of 200 a.u., which are similar to XRD intensities of human bone. In subsequent comparisons, MG-63 cell viability and differentiation into osteoblast-like cells were assessed on HA/β-TCP and HA/β-TCP + Ar-GDP surfaces, and Ar-GDP treatments led to improved cell growth and alkaline phosphatase activities. The present data indicate that GDP surface treatment modified HA/β-TCP surfaces by eliminating contaminants, and the resulting graft material enhanced bone regeneration.

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.

Randomized clinical trial of ridge preservation using porcine bone/cross-linked collagen vs. bovine bone/non-cross-linked collagen: cone beam computed tomographic analysis

PURPOSE

The aim of this study was to radiographically compare horizontal and vertical alterations of the alveolar ridge after ridge preservation using different combinations of biomaterials.

MATERIALS AND METHODS

The patients were randomly assigned into two groups: (a) the test group, which received collagenated porcine bone plus cross-linked collagen membrane (n = 15), and (b) the control group, which received collagenated bovine bone plus non-cross-linked collagen membrane (n = 15). Cone beam computed tomography (CBCT) was performed immediately after ridge preservation and 4 months thereafter to compare the horizontal and vertical alterations of the ridge. Intention-to-treat (ITT) and per protocol (PP) analyses were performed.

RESULTS

In both analyses, there was no statistically significant difference in the horizontal alteration of the alveolar ridge between the test and control groups: -1.3 ± 0.6 (ITT)/1.2 ± 0.5 (PP) vs. -1.5 ± 0.9 mm at the 1-mm level; -1.2 ± 0.7 (ITT and PP) vs. -1.2 ± 0.7 mm at the 3-mm level; and -0.9 ± 0.7 (ITT)/ -0.9 ± 0.7 (PP) vs. -0.9 ± 0.9 mm at the 5-mm level, whereas the vertical height in the midfacial area was significantly reduced in the test group compared with the control group: --1.1 ± 2.8 (ITT)/1.5 ± 3.0 (PP) vs. -0.7 ± 1.8 mm.

CONCLUSIONS

The horizontal ridge alteration in ridge preservation did not differ significantly between using the test the control groups, but the vertical ridge alteration was more pronounced when using the test group (KCT0001709).

Evaluation of hyaluronic matrix efficacy in sinus augmentation: a randomized-controlled histomorphometric and micro-computed tomography analysis

The objective of the present study was to test the hypothesis that the addition of hyaluronic acid-based matrix to collagenated heterologous bone graft for sinus augmentation would enhance bone formation compared to collagenated heterologous bone graft alone in the early healing period, by micro-computed tomography and histomorphometry. Thirteen systemically healthy patients requiring bilateral two-stage maxillary sinus augmentation (residual crest height≤4mm) were enrolled in this split-mouth prospective randomized controlled study. One sinus side as a control group was grafted with only collagenated heterologous bone graft; the other region as a test group was grafted with hyaluronic matrix and collagenated heterologous bone graft. Bone biopsy samples were taken after 4 months during the dental implant surgery and analyzed using micro-computed tomography and histomorphometric parameters. According to the micro-computed tomography and histomorphometric results, a significantly higher percentage of new bone was observed in the test group when compared to the control group after 4 months of healing. This study confirmed the hypothesis that the addition of hyaluronic matrix to collagenated heterologous bone graft for sinus augmentation enhances bone formation compared to collagenated heterologous bone graft alone in the early healing period.

Do Porous Titanium Granule Grafts Affect Bone Microarchitecture at Augmented Maxillary Sinus Sites? A Pilot Split-Mouth Human Study

BACKGROUND

The aim of this randomized controlled clinical study was to analyze the bone microarchitecture at augmented maxillary sinus sites by using different materials in patients to compare the effect of porous titanium granules as a sinus augmentation material with bone microstructural features.

MATERIALS AND METHODS

Eight subjects with bilateral atrophic posterior maxilla of residual bone height <4 mm included in this study and each patient was treated with bilateral sinus augmentation procedure using xenograft with equine origin (Apatos, Osteobiol; Tecnoss Dental) and xenograft (1 g) + porous titanium (1 g) granules (Natix; Tigran Technologies AB). Sixteen human bone biopsy samples were taken from patients receiving two-stage sinus augmentation therapy during implant installation and analyzed using microcomputerized tomography. Three-dimensional bone structural parameters were analyzed in details: tissue volume, bone volume, percentage of bone volume, bone surface and bone surface density, bone specific surface, trabecular thickness trabecular separation, trabecular number, trabecular pattern factor, structural model index, fractal dimension, and bone mineral density.

RESULTS

No statistically significant differences were found between groups according to bone structural parameters.

CONCLUSIONS

Porous titanium grafts may ensure a space for new bone formation in the granules, which may be a clinical advantage for long-term success.

Effect of Porous Titanium Granules on Bone Regeneration and Primary Stability in Maxillary Sinus: A Human Clinical, Histomorphometric, and Microcomputed Tomography Analyses

The aim of this randomized controlled study was to comparatively analyze the new bone (NB), residual bone, and graft-bone association in bone biopsies retrieved from augmented maxillary sinus sites by histomorphometry and microcomputed tomography (MicroCT) in a split-mouth model to test the efficacy of porous titanium granules (PTG) in maxillary sinus augmentation. Fifteen patients were included in the study and each patient was treated with bilateral sinus augmentation procedure using xenograft (equine origine, granule size 1000-2000 μm) and xenograft (1 g) + PTG (granule size 700-1000 μm, pore size >50 μm) (1 g), respectively. After a mean of 8.4 months, 30 bone biopsies were retrieved from the implant sites for three-dimensional MicroCT and two-dimensional histomorphometric analyses. Bone volume and vital NB percentages were calculated. Immediate after core biopsy, implants having standard dimensions were placed and implant stability quotient values were recorded at baseline and 3 months follow-up. There were no significant differences between groups according to residual bone height, residual bone width, implant dimensions, and implant stability quotient values (baseline and 3 months). According to MicroCT and two-dimensional histomorphometric analyses, the volume of newly formed bone was 57.05% and 52.67%, and 56.5% and 55.08% for xenograft + PTG and xenograft groups, respectively. No statistically significant differences found between groups according to NB percentages and higher Hounsfield unit values were found for xenograft + PTG group. The findings of the current study supports that PTG, which is a porous, permanent nonresorbable bone substitute, may have a beneficial osteoconductive effect on mechanical strength of NB in augmented maxillary sinus.

Randomized Clinical Trial of Maxillary Sinus Grafting using Deproteinized Porcine and Bovine Bone Mineral

BACKGROUND

Deproteinized porcine bone mineral (DPBM) was recently developed and commercially available in maxillary sinus grafting, in which demineralized bovine bone mineral (DBBM) was widely used.

OBJECTIVES

The present randomized controlled clinical trial aimed to compare histological bone quality and radiographic volume stability in maxillary sinuses grafted with DPBM and DBBM.

MATERIALS AND METHODS

Twenty sinuses in 16 participants were enrolled and randomly allocated to control and test groups using sequentially numbered, sealed envelopes; laterally approached sinus grafting with DBBM and DPBM, respectively. All participants were blinded to the group assignment during the entire experiment. After standardized osteotomy at the lateral wall of the maxillary sinus, the sinus membrane was elevated, and the control or test biomaterial was grafted. Computed tomography (CT) images were taken immediately after surgery, and another CT and trephine biopsy was taken for radiographic and histological analyses after 6 months. The histological bone quality was measured as a primary outcome, and changes in the height and volume of the graft were evaluated in the reconstructed CT images as secondary outcomes.

RESULTS

Fifteen sites (7 and 8 sites for control and test group) in 11 participants were finally included in the per protocol (PP) analysis, and 16 sites (7 and 9 sites, respectively) in 12 participants were included in the intention-to-treat (ITT) analysis; there were four drop-outs and one minor protocol violation. In both statistical analyses, the test groups showed comparable new bone formation and residual biomaterials in histology, and both groups exhibited minimal volume/height changes in radiographies. However, smaller sizes of residual biomaterials were observed in the histological samples from the test compared to control sites, despite the use of the same sizes of both biomaterials.

CONCLUSIONS

The results suggested that DPBM might produce comparable bone formation and volumetric stability with DBBM in maxillary sinus grafting, however, further clinical study with longer-term periods and larger sample sizes should be needed for confirming this suggestion.

Biologic and clinical aspects of integration of different bone substitutes in oral surgery: a literature review

Many bone substitutes have been proposed for bone regeneration, and researchers have focused on the interactions occurring between grafts and host tissue, as the biologic response of host tissue is related to the origin of the biomaterial. Bone substitutes used in oral and maxillofacial surgery could be categorized according to their biologic origin and source as autologous bone graft when obtained from the same individual receiving the graft; homologous bone graft, or allograft, when harvested from an individual other than the one receiving the graft; animal-derived heterologous bone graft, or xenograft, when derived from a species other than human; and alloplastic graft, made of bone substitute of synthetic origin. The aim of this review is to describe the most commonly used bone substitutes, according to their origin, and to focus on the biologic events that ultimately lead to the integration of a biomaterial with the host tissue.

Investigation of a pre-clinical mandibular bone notch defect model in miniature pigs: clinical computed tomography, micro-computed tomography, and histological evaluation

OBJECTIVES

To validate a critical-size mandibular bone defect model in miniature pigs.

MATERIALS AND METHODS

Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks.

RESULTS

In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect.

CONCLUSION

The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.

A Novel Porcine Graft for Regeneration of Bone Defects

Bone regeneration procedures require alternative graft biomaterials to those for autogenous bone. Therefore, we developed a novel porcine graft using particle sizes of 250–500 μm and 500–1000 μm in rabbit calvarial bone defects and compared the graft properties with those of commercial hydroxyapatite (HA)/beta-tricalcium phosphate (β-TCP) over eight weeks. Surgery was performed in 20 adult male New Zealand white rabbits. During a standardized surgical procedure, four calvarial critical-size defects of 5 mm diameter and 3 mm depth were prepared. The defects were filled with HA/β-TCP, 250–500 μm or 500–1000 μm porcine graft, and control defects were not filled. The animals were grouped for sacrifice at 1, 2, 4, and 8 weeks post-surgery. Subsequently, sample blocks were prepared for micro-computed tomography (micro-CT) scanning and histological sectioning. Similar bone formations were observed in all three treatment groups, although the 250–500 μm porcine graft performed slightly better. Rabbit calvarial bone tissue positively responded to porcine grafts and commercial HA/β-TCP, structural analyses showed similar crystallinity and porosity of the porcine and HA/β-TCP grafts, which facilitated bone formation through osteoconduction. These porcine grafts can be considered as graft substitutes, although further development is required for clinical applications.

A prospective study on the effectiveness of newly developed autogenous tooth bone graft material for sinus bone graft procedure

PURPOSE

The purpose of this prospective study was to evaluate the effectiveness of newly developed autogenous tooth bone graft material (AutoBT)application for sinus bone graft procedure.

MATERIALS AND METHODS

The patients with less than 5.0 mm of residual bone height in maxillary posterior area were enrolled. For the sinus bone graft procedure, Bio-Oss was grafted in control group and AutoBT powder was grafted in experimental group. Clinical and radiographic examination were done for the comparison of grafted materials in sinus cavity between groups. At 4 months after sinus bone graft procedure, biopsy specimens were analyzed by microcomputed tomography and histomorphometric examination for the evaluation of healing state of bone graft site.

RESULTS

In CT evaluation, there was no difference in bone density, bone height and sinus membrane thickness between groups. In microCT analysis, there was no difference in total bone volume, new bone volume, bone mineral density of new bone between groups. There was significant difference trabecular thickness (0.07 µm in Bio-Oss group Vs. 0.08 µm in AutoBT group) (P=.006). In histomorphometric analysis, there was no difference in new bone formation, residual graft material, bone marrow space between groups. There was significant difference osteoid thickness (8.35 µm in Bio-Oss group Vs. 13.12 µm in AutoBT group) (P=.025).

CONCLUSION

AutoBT could be considered a viable alternative to the autogenous bone or other bone graft materials in sinus bone graft procedure.

Pre-clinical evaluation of the osteogenic potential of bone morphogenetic protein-2 loaded onto a particulate porcine bone biomaterial

AIM

The objective of study was to determine the osteogenic potential of bone morphogenetic protein-2 (BMP-2) loaded onto a particulate porcine bone mineral (PBM) biomaterial using a sinus augmentation model.

METHODS

Release kinetics of BMP-2/PBM was determined in vitro. Eight rabbits received BMP-2/PBM or PBM alone into contra-lateral sinus sites. The animals were killed following a 2-week healing interval for micro-CT and histometrical analysis.

RESULTS

Approximately 40% of the BMP-2 was released from PBM over the first 3 days in vitro; release maintained at a reduced level through day 21. In vivo, total augmented implant volume did not differ significantly between treatments. However, local bone formation was enhanced in the BMP-2/PBM group compared with PBM control (10.5% versus 6.6%; p = 0.03), specifically in the central aspect of the PBM implant (14.2% versus 5.5%; p < 0.01) and adjoining the Schneiderian membrane (11.9% versus 5.0%; p < 0.05). There were no significant overall differences in residual biomaterial and fibrovascular tissue.

CONCLUSION

Bone morphogenetic protein-2 enhanced local bone formation in the rabbit maxillary sinus model following implantation using a PBM carrier.

Bone formation in sinus augmentation procedures using autologous bone, porcine bone, and a 50 : 50 mixture: a human clinical and histological evaluation at 2 months

OBJECTIVES

The aim of this study was to perform a 2 months clinical and histological comparison of autologous bone, porcine bone, and a 50 : 50 mixture in maxillary sinus augmentation procedures.

MATERIALS AND METHODS

A total of 10 consecutive patients, undergoing two-stage sinus augmentation procedures using 100% autologous bone (Group A), 100% porcine bone (Group B), and a 50 : 50 mixture of autologous and porcine bone (Group C) were included in this study. After a 2-month healing period, at the time of implant insertion, clinical evaluation was performed and bone core biopsies were harvested and processed for histological analysis.

RESULTS

The postoperative healing was uneventful regardless of the materials used for the sinus augmentation procedures. The histomorphometrical analysis revealed comparable percentages of newly formed bone, marrow spaces, and residual grafted material in the three groups.

CONCLUSION

The clinical and histological results of this study indicated that porcine bone alone or in combination with autologous bone are biocompatible and osteoconductive materials and can be successfully used in sinus augmentation procedures.

Flap versus flapless procedure for ridge preservation in alveolar extraction sockets: a histological evaluation in a randomized clinical trial

OBJECTIVE

The aim of this study was to evaluate and compare the histological and histomorphometric features of two different procedures carried out in extraction socket grafting; namely, the flapped and flapless technique.

MATERIALS AND METHODS

Patients considered eligible for the study were randomized to receive tooth extraction and ridge preservation with the porcine bone and collagen membrane, with a full thickness mucoperiosteal flap and primary soft tissue closure (control group), or, with a flapless procedure and a secondary soft tissue closure (test group). After 3 months of healing, the surgical re-entry procedure was performed and implants were inserted in the test as well as in the control sites. Bone core samples were harvested from both groups and processed to be observed under light microscopy. Outcome variables were percentages of newly formed bone, residual graft particles and marrow spaces.

RESULTS

Thirty-four patients were enrolled in the study. All of the scheduled implants were placed. Histological and histomorphometrical analyses did not report significant differences between the two groups (with P-values ranging from 0.690 to 0.917). The mean percentages of newly formed bone, soft tissues and residual grafted particles were 22.5 and 22.5%, 59.3 and 59.4%, and 18.6 and 18.2% respectively for flap and flapless approach.

CONCLUSION

No histological and histomorphometrical differences were observed when comparing the flap and the flapless technique for tooth extraction and socket grafting procedures.

Use of sintered xenograft over allograft for ridge augmentation: technique note

Patients often present with tooth or implant complications with loss of significant bone width and the need for bone volume for implant placement and maintenance of ridge contour for esthetics. The technique described is a low-morbidity, highly predictable method to restore these sites. A case series of 12 patients followed for 2 years is presented.

Ultrastructural study by backscattered electron imaging and elemental microanalysis of bone-to-biomaterial interface and mineral degradation of porcine xenografts used in maxillary sinus floor elevation

OBJECTIVES

The aim of this study was to carry out an ultrastructural study of the biomaterial-to-bone interface and biomaterial mineral degradation in retrieved bone biopsies following maxillary sinus augmentation using collagenized porcine xenografts (Osteobiol(®) Mp3) in 15 clinical cases.

MATERIALS AND METHODS

Nine months after sinus lifting, bone cores were harvested from the maxillary sinus. The specimens were processed for observation under a scanning electron microscope with backscattered electron imaging (SEM-BSE). In addition, chemical analysis and elemental mapping of the mineral composition were generated using a microanalytical system based on energy-dispersive X-ray spectrometry (EDX).

RESULTS

No clinical complications were evident during surgery. Scanning electron microscopy revealed that newly formed bone had become closely attached to the xenograft. Statistical analysis showed a significantly high Ca/P ratio in the biomaterial (2.46 ± 0.16) and at the bone interface (2.00 ± 0.48) compared to bone (1.97 ± 0.36), which suggests that there may be a gradual diffusion of Ca ions from the biomaterial into the newly forming bone at the interface as part of the biomaterial's resorption process. EDX analysis of the residual porcine biomaterial at different points showed some particle categories with different mean ratios of Ca/P according to size, pointing to different stages of the resorption process.

CONCLUSIONS

The biomaterial proved to be biocompatible, bioreabsorbable and osteoconductive when used as a bone substitute for maxillary sinus elevation. SEM-BSE revealed that newly formed bone had become closely attached to the xenografts. EDX analysis monitored the resorption process of the porcine bone xenograft. Elemental mapping showed that there was a gradual diffusion of Ca ions from the biomaterial to the newly forming bone at the interface.

Histomorphometric analysis of maxillary sinus augmentation using an alloplast bone substitute

PURPOSE

To evaluate the regenerative potential of a fully synthesized homogenous hydroxyapatite:β-tricalcium phosphate 60:40 alloplast material in sinus lift procedures.

MATERIALS AND METHODS

Hydroxyapatite:β-tricalcium phosphate was used for sinus floor augmentation. After 9 months, 12 biopsies were taken from 12 patients. Routine histologic processing was performed and specimens were analyzed using a light microscope and a digital camera.

RESULTS

Histologic evaluation showed 26.4% newly formed bone, 27.3% residual graft material, and 46.3% bone marrow. The osteoconductive index was 33.5%.

CONCLUSIONS

Hydroxyapatite:β-tricalcium phosphate 60:40 alloplast material was found to be biocompatible and osteoconductive in maxillary sinus augmentation procedures.

Biological response to porcine xenograft implants: an experimental study in rabbits

PURPOSE

The aim of this study was to evaluate the effect of a new porcine biomaterial and collagen paste in 20 New Zealand rabbits.

MATERIALS AND METHODS

Forty implants using a porcine xenograft made up of 80% corticocancellous collagenated bone particles of ≤300 μm in size were placed in the proximal metaphyseal area of both tibiae. Four periods of time were formed: 1h, 5, 8, and 15 months. After implantation, an anteroposterior and lateral radiological study was carried out. Samples were sectioned at 5 μm and stained using hematoxylin-eosin, Masson's trichromic, and Gordon-Switt reticulin stains.

RESULTS

These results confirmed the biocompatibility of this porcine biomaterial-collagen paste; only a few, occasional macrophages and scattered lymphocytes were observed. No fibrosis was observed between the implants and the bone. Moreover, the material was osteoconductive acting as a "scaffold" for bone cells, and there was a progressive increase in bone growth in and around the implants.

CONCLUSION

This new porcine biomaterial-collagen paste seemed to be biocompatible, bioresorbable, and osteoconductive.

Biomechanical and bone histomorphological evaluation of two surfaces on tapered and cylindrical root form implants: an experimental study in dogs

PURPOSE

The aim of this study was to evaluate the early bone response of tapered and cylindrical root form implants with two different surface treatments in fresh extraction sockets after 4 and 8 weeks.

MATERIALS AND METHODS

Surface treatments and implant design comprised (n = 9 each): tapered with dual acid-etched surface; tapered with dual acid-etched and sandblasted surface (T DAE SB); cylindrical with dual acid-etched surface (C DAE); and cylindrical with dual acid-etched and sandblasted surface (C DAE SB). Implants were placed in the distal sockets of mandibular premolars (2 P2, 3 P3, 4 P4 ) of six beagle dogs, remaining in vivo for 4 and 8 weeks. After sacrifice, the implants were subjected to torque to the point of interface fracture and subsequently nondecalcified for histomorphological study. Statistical analysis was performed by a General Linear Model (GLM) analysis of variance model with a significance level of 5%.

RESULTS

Torque to interface fracture was significantly greater for the C DAE SB group than for the other groups (p < .001). Histomorphological analysis showed woven bone formation around all implant surfaces at 4 weeks and its replacement by lamellar bone at 8 weeks. Study time (4 or 8 weeks) did not affect torque measures.

CONCLUSIONS

The double acid-etched and sandblasted sample surface increased early bone biomechanical fixation of both cylindrical and tapered root form implants. The cylindrical root form implants showed higher torque to interface fracture values when compared with the tapered root form implants. The C DAE SB surface group showed the highest biomechanical fixation values (p < .001).

A randomized clinical trial to evaluate and compare implants placed in augmented versus non-augmented extraction sockets: 3-year results

BACKGROUND

The alveolar ridge undergoes reabsorption and atrophy subsequent to tooth removal and thus exhibits a wide range of dimensional changes. Preservation of the alveolar crest after tooth extraction is essential to enhance the surgical site before implant fixture placement. The aim of this randomized clinical study is to investigate and compare the need for additional augmentation procedures at implant insertion, as well as the success rate and marginal bone loss for implants placed in the grafted sites versus those placed in naturally healed sites.

METHODS

Forty patients with ≥1 hopeless tooth were randomly allocated to: 1) a test group, receiving extraction and grafting corticocancellous porcine bone; and 2) a control group, receiving extraction without any graft. After 7 months of healing, implants were inserted in each of the sites. The implants were submerged and loaded after 4 months with metal-ceramic rehabilitation. The follow-up included evaluation of implant diameter and length, the need for additional augmentation procedures at implant placement, implant failure, and marginal bone level changes. All patients were followed over a 3-year period.

RESULTS

One implant failed in the control group at the second stage of surgery (6 months after placement); one implant failed in the test group after 2 years of loading. The cumulative implant success rate at the 3-year follow-up visit reached 95% for both groups. No statistically significant differences were detected for marginal bone changes between the two groups.

CONCLUSIONS

It was concluded that implants placed into grafted extraction sockets exhibited a clinical performance similar to implants placed into non-grafted sites in terms of implant survival and marginal bone loss. However, grafted sites allowed placement of larger implants and required less augmentation procedures at implant placement when compared to naturally healed sites.

Histologic and Histometric Evaluation of Bovine Cancellous Bone and Beta-Tricalcium Phosphate 45 Months After Grafting in Maxillary Sinus

The aim of this report is to determine the long-term histologic and histometric evaluation of beta-tricalcium phosphate (beta-TCP) and bovine cancellous bone grafted into the left maxillary sinus of a patient in order to augment the sinus floor to prepare it for receiving an implant. Beta-TCP and bovine cancellous bone (BCB) were grafted into the left maxillary sinus at the extracted sites of maxillary left first and second molars of a 62-year-old male patient. Using osteotome technique, 45 months later, core biopsies were taken for histologic and histometric comparison of the newly formed bone. Histometric and histologic evaluation of both specimens revealed a normal maxillary bone structure with 23.08% calcified bone and 76.92% marrow and connective tissue for the beta-TCP grafted site, and 24.81% calcified bone with 75.19% marrow and connective tissue for the BCB grafted site. No residual grafting material was seen in either specimen. Both beta-TCP and BCB were completely resorbed and replaced by new bone 45 months after grafting. Histologic results of the newly formed bone were similar for both grafting materials.