Effect of Recombinant Human Platelet-Derived Growth Factor on Healing of Chronic Periapical Tissue Pathosis Following Apical Surgery in a Canine Model: A Histomorphometric and Microcomputed Tomography Analysis.

This canine in vivo study assessed the effect of recombinant human platelet-derived growth factor (rhPDGF) on the healing of periapical tissues following apical surgery. From a total of 96 premolar teeth, 64 teeth from six beagle dogs (2 years old) were classified as experimental and were randomly assigned to four experimental groups (16 teeth per group). After having the pulp extirpated, leaving teeth open to the oral cavity for 1 week, and sealing with an immediate restorative material for 8 weeks, nonsurgical endodontic treatment was performed. A split-mouth design was used, and intra-animal randomization of treatment sides was applied to the groups as follows: apical curettage + 1.5-mm root-end resection (Group 1); apicoectomy + mineral trioxide aggregate (MTA) root-end filling (Group 2); apicoectomy + MTA root-end filling + rhPDGF (Group 3); and apical curettage + rhPDGF (Group 4). The animals were sacrificed 24 months after apical surgery, and histologic and µCT analyses were performed for bone volume loss (BVL). Group 1 showed partial resolution of the periapical lesions without signs of tissue regeneration (BVL: 49.09 ± 10.97 mm3). Group 2 had minimal bone regeneration and showed cementum reformation in 9 teeth, with no direct attachment to the MTA (BVL: 35.34 ± 10.97 mm3). Group 3 showed regeneration of all damaged apical tissues without direct contact between the cementum and MTA (BLV: 4.51 ± 1.55 mm3). Group 4 showed regeneration of PDL, bone, and cementum and attachment of functional cementum fibers (BVL: 2.82 ± 2.3 mm3). The difference in BVL was statistically significant only for Groups 1 and 2 (P < .05). rhPDGF may help regenerate apical tissue structures following apical surgery.

Effect of Selective Serotonin Reuptake Inhibitor (Paroxetine) on Newly Formed Bone Volume: Real-Time In Vivo Micro-computed Tomographic Analysis.

INTRODUCTION: Selective serotonin reuptake inhibitors (SSRIs) are commonly used to treat depression and anxiety. The purpose of this study was to assess in real time the effect of paroxetine, an SSRI, on newly formed bone volume (NFBV) in standardized calvarial defects (SCDs) in rats. METHODS: Fourteen Wistar albino female rats with a mean age of 7.5 months and a mean weight of 275 g were used. The animals were randomly divided into 2 groups. The experimental group was given paroxetine 8 weeks before the surgical procedure and throughout the experiment, and the control group was given a placebo 8 weeks before the surgical procedure and throughout the experiment. In each group, 14 SCDs measuring 4.6 mm in diameter were created on the parietal bone. In both groups, a Bio-Oss + collagen membrane was placed. All defects showed primary closure. The volume of the newly formed bone (NFBV) was measured using in vivo micro-computed tomographic imaging. Measurements were taken at days 0, 14, 28, 42, and 56 after surgery using real-time assessment with micro-computed tomographic imaging. RESULTS: The mean NFBV was 17.12 ± 4.52 mm3 and 12.52 ± 4.78 mm3 for the control and experimental groups, respectively, at day 56. The differences between the 2 groups were statistically significant (P < .05) at all time intervals. CONCLUSIONS: Paroxetine intake significantly reduced the amount of regenerated NFBV and the rate of new bone formation.

Assessment of dentin mineral density of human teeth using micro-computed tomography in two kilovoltage levels.

A significant advancement in micro-computed tomography (µCT) translational application in endodontics has occurred. The purpose of the study was to assess the applications of a new method to measure dentin mineral density (DMD) and to compare between 2 levels of energy sources. Two sets of standardized porous solid hydroxyapatite (HA) phantoms, with mineral densities of 0.25 g/cm3 and 0.75 g/cm3, respectively were embedded in aluminum foil. The µCT homogeneity and noise in the HA phantoms were analyzed using 50 kV and 100 kV energy sources. DMD of 66 extracted human teeth was measured at the cemento-enamel junction (CEJ), mid-root, and apical levels. Assessment included linearity between the energy source and the DMD measurement. The quality of the images obtained from the 2 energy sources was compared and analyzed statistically. HA phantom rods and validation methods showed that 100 kV provided a more accurate measurement of the DMD in all groups tested. The 100 kV 3D reconstructed µCT images displayed a more defined details of the dentin structure. A statistically significant difference was found between 100 and 50 kV (p < 0.05) in all measured areas except for the mid-root. Using micro-computed tomography is a practical and non-destructive method to measure dentin density. 100 kV energy source provides clearer and more consistent images.

Buccal Bone Remodeling Around Immediate Implants in STZ-Induced Diabetic Dogs: A Histologic and Microcomputed Tomographic Analysis.

Buccal bone remodeling around immediate implants placed in animals with streptozotocin (STZ)-induced diabetes has not been investigated. The present histologic and microcomputed tomography (µCT) in vivo experiment assessed the buccal bone remodeling around immediate implants, extraction socket healing, and bone-to-implant contact (BIC) in dogs with and without STZ-induced diabetes. Three male beagle dogs with STZ-induced diabetes and three healthy dogs (controls) were included. Fasting blood glucose levels were measured using a glucometer. Under general anesthesia, all animals underwent atraumatic tooth extraction of bilateral maxillary and mandibular second premolar teeth using Piezosurgery and immediate implant placement in the distal root socket. Primary closure was achieved for all implants and adjacent socket sites. After 11 months, all animals were sacrificed, and buccal bone thickness (BBT), marginal bone loss (MBL), BIC, and mesial extraction socket bone volume were assessed in control and diabetic animals using histologic and µCT examination. High-resolution µCT analyses were performed to identify the percentage of osteocytes and blood vessels in bone specimens harvested from a mesial extraction socket in each group. BBT and BIC were significantly higher in control dogs (P < .05), and diabetic dogs demonstrated significantly more MBL than control dogs (P < .05). Compared to healthy subjects, the sockets of induced diabetic dogs lost over 50% of bone horizontally and vertically. Control group had more significant osteocytes (38.85%) and blood vessels (37.87%), whereas the same values for STZ-induced diabetic dogs were 27.92% and 27.76%, respectively. Buccal bone loss and MBL were significantly higher around immediate implants placed in dogs with STZ-induced diabetes and were associated with multiple implant buccal thread exposure. A large percentage of socket space in diabetic dogs healed with nonosseous structure following tooth extraction.

Serological Detection of Flavivirus Infections in Saudi Baboons.

To evaluate the risk to public health from Flaviviruses in the southwest region of the Kingdom of Saudi Arabia, we screened as sentinels, 50 commensal hamadryas baboons located at a peri-domestic site on the outskirts of Ta'if City in February 2013. Of the baboons, 12% [95% CI 5, 24], 0% [95% CI 0, 7] and 10% [95% CI 3, 22] were seropositive in a pan-Flavivirus ELISA (anti-pan-WNV 1-2, Usutu, Zika), Dengue virus 1-4 ELISA (anti-DENV 1-4) and WNV-1 PRNT, respectively, indicating Flavirus exposures of the subjects with possible risk to public health in the area.

Evaluation of Recombinant Human Platelet-Derived Growth Factor or Enamel Matrix Derivative Plus Calcium Hydroxide for Pulp Capping: A Randomized Controlled Human Clinical Trial.

This in vivo study assessed calcium hydroxide's effect as a matrix carrier for recombinant human platelet-derived growth factor (rhPDGF) and enamel matrix protein (EMD) on pulp tissue healing following pulp capping. Intact premolar sites (n = 18) were included. Coronal access and pulpotomy were performed, and each tooth was exposed to the oral cavity for 1 hour before pulp capping was performed. Teeth were randomly assigned to one of the following pulp-capping groups (n = 6 each): Group 1 (CaOH2 only); Group 2 (CaOH2+EMD); and Group 3 (CaOH2+rhPDGF). Coronal access cavities were then sealed. Immediate preoperative, postoperative, and 4-month follow-up radiographs were taken. At 4 months, teeth were extracted atraumatically and histomorphometric and micro-CT analyses were performed. Group 1 showed formation of thin, uneven, highly porous dentin-like structure with tunnel defects (average thickness: 0.18 to 0.19 mm). Lack of continuity of the newly formed tissue and interrupted communication tunnels were seen between the pulpal space and pulp-capping material. Group 2 showed formation of highly dense, nonporous, even-thickness dentin-like structure obliterating multiple areas of the pulp space (average thickness: 0.9 to 0.94 mm). Abundant odontoblast lacunae were present in the pulp and structure. Group 3 showed formation of an inconsistent, uneven dentin-like structure that appeared highly porous (average thickness: 1.04 to 1.05 mm). It was without tunneling, and abundant odontoblastic lacunae were present. No statistically significant differences were found between Groups 2 and 3, but both were richer in newly formed dentin-like structure with more thickness than Group 1 (P < .05). Addition of EMD to CaOH2 can result in multiple root canal calcifications, mostly in the coronal and apical thirds of the canals. The calcified tissue does not appear to resemble secondary dentin in form, shape, amount, or density. Addition of rhPDGF to CaOH2 may not cause root canal calcifications. The newly formed structure differs from secondary dentin in degree of mineralization, porosity, and density.

Regeneration of Secondary Dentin Using Recombinant Human Platelet-Derived Growth Factor and MTA for Pulp Capping: A Randomized Controlled Human Clinical Trial.

This in vivo study assessed the effect of mineral trioxide aggregate (MTA) as a matrix carrier for recombinant human platelet-derived growth factor (rhPDGF) and enamel matrix protein (EMP) on pulp tissue healing following pulp capping. Eighteen intact human premolars scheduled for extraction were included. Coronal access and pulpotomy were performed, and each tooth was left exposed to the oral cavity for 1 hour before pulp capping was performed. Teeth were randomly assigned to one of the following pulp-capping groups (n = 6 each): Group 1 (MTA only); Group 2 (MTA+EMP); or Group 3 (MTA+rhPDGF). Coronal access cavities were then sealed. Immediate preoperative, postoperative, and 4-month follow-up radiographs were taken. At 4 months, the teeth were extracted atraumatically, and histomorphometric and micro-computed tomography (µCT) analyses were performed. Group 1 showed a thin, uneven, irregular dentin-like structure. Its average thickness was 0.3 ± 0.084 mm measured histologically and 0.29 ± 0.091 mm measured by µCT. Group 2 showed of a nonporous, even-thickness dentin-like structure with multiple root-canal obliterations. Highly dense, atubular dentin-like structures associated with presence of odontoblastic lacunae were seen. The structure's average thickness was 0.87 ± 0.09 mm (histologically) and 0.81 ± 0.17 mm (µCT). Group 3 showed a thick and complete 3D continuous seal of newly formed dentin-like structure covering the pulpal space. It resembled secondary dentin in form, porosity, and tubular structural organization, and its average thickness was 0.94 ± 0.02 mm (histologically) and 0.91 ± 0.09 mm (µCT). Groups 2 and 3 showed higher amounts of newly formed dentin-like structure, that was also thicker, than Group 1 (P < .05). No statistically significant differences in structure thickness were found between Groups 2 and 3. The nature of the structure can differ if rhPDGF or EMP is added to MTA for pulp-capping purposes. Combination of rhPDGF and MTA resulted in a newly formed structure resembling secondary dentin, whereas a combination of EMP and MTA produced a nonporous, highly dense dentinal-like structure associated with significant root-canal obliterations.

The Efficacy of Recombinant Platelet-Derived Growth Factor on Beta-Tricalcium Phosphate to Regenerate Femoral Critical Sized Segmental Defects: Longitudinal In Vivo Micro-CT Study in a Rat Model.

Background and Objectives: Beta-tricalcium phosphate (beta-TCP) has been used for bone regeneration. The objective of this study was to assess longitudinally, the regeneration of critical sized segmental defects (CSSD) in rat femur using beta-TCP with or without recombinant platelet-derived growth factor (PDGF) through in vivo micro-computed tomography (micro-CT). Materials and Methods: Following ethical approval unilateral femoral CSSD measuring 5 mm was surgically created, under general anesthesia, in 30 male Wistar-Albino rats (aged 12-18 months; weighing 450-500 g). CSSD was stabilized using titanium mini-plate (4 holes, 1.0 mm thick with 8 mm bar). Depending upon biomaterial used for regeneration, the animals were randomly divided into: Control group (N = 10): CSSD covered with resorbable collagen membrane (RCM) only; Beta-TCP group (N = 10): CSSD filled with beta-TCP and covered by RCM; Beta-TCP + PDGF group (N = 10): CSSD filled with beta-TCP soaked in recombinant PDGF and covered by RCM. Longitudinal in vivo micro-CT analysis of the CSSD was done postoperatively at baseline, 2nd, 4th, 6th, and 8th weeks to assess volume and mineral density of newly formed bone (NFB) and beta-TCP. Results: Significant increase in NFB volume (NFBV) and mineral density (NFBMD) were observed from baseline to 8-weeks in all groups. Based on longitudinal in vivo micro-CT at 8-weeks, beta-TCP + PDGF group had significantly higher (p < 0.01) NFBV (38.98 ± 7.36 mm3) and NFBMD (3.72 ± 0.32 g/mm3) than the beta-TCP (NFBV-31.15 ± 6.68 mm3; NFBMD-2.28 ± 0.86g/mm3) and control (NFBV: 5.60 ± 1.06 mm3; NFBMD: 0.27 ± 0.02 g/mm3) groups. Significantly, higher reduction in beta-TCP volume (TCPV) and mineral density (TCPMD) were 1 observed in the beta-TCP + PDGF group when compared to the beta-TCP group. Conclusion: Addition of recombinant PDGF to beta-TCP enhanced bone regeneration within rat femoral CSSD and increased resorption rates of beta-TCP particles.

Guided Bone Regeneration of Femoral Segmental Defects using Equine Bone Graft: An In-Vivo Micro-Computed Tomographic Study in Rats.

Background and objectives: Guided bone regeneration (GBR) is commonly used for osseous defect reconstruction. The objective of this study was to evaluate in real-time (in-vivo) the efficacy of equine bone graft for GBR in segmental critical-size defects (CSD) of the femur in a rat model. Materials and methods: Following ethical approval, 30 male Wistar-Albino rats (age 12-14 months/weight 450-500 grams) were included. Under general-anesthesia, a mid-diaphyseal segmental CSD (5 mm) was created in the femur and stabilized using titanium Miniplate(4 holes,1.0 mm thickness). Depending upon material used for GBR, animals were randomly divided into three groups(n = 10/per group). Negative control-Defect covered with resorbable collagen membrane(RCM); Positive control-Defect filled with autologous bone and covered by RCM; Equine bone-Defect filled with equine bone and covered by RCM. Real-time in-vivo Micro-CT was performed at baseline, 2, 4, 6 and 8 weeks to determine volume and mineral density of newly formed bone (NFB) and remaining bone graft particles (BGP). Results: In-vivo micro-CT revealed increase in volume and mineral density of NFB within defects from baseline to 8-weeks in all groups. At 8-weeks NFB-volume in the equine bone group(53.24 ± 13.83 mm3; p < 0.01) was significantly higher than the negative control(5.6 ± 1.06 mm3) and positive control(26.07 ± 5.44 mm3) groups. Similarly, NFB-mineral density in the equine bone group(3.33 ± 0.48 g/mm3; p < 0.01) was higher than the other (negative control-0.27 ± 0.02 g/mm3; positive control-2.55 ± 0.6 g/mm3). A gradual decrease in the BGP-volume and BGP-mineral density was observed. Conclusion: The use of equine bone for GBR in femoral segmental defects in rats, results in predictable new bone formation as early as 2-weeks after bone graft placement.

Time series analysis and mortality model of dog bite victims presented for treatment at a referral clinic for rabies exposure in Monrovia, Liberia, 2010-2013.

We developed time trend model, determined treatment outcome and estimated annual human deaths among dog bite victims (DBVs) from 2010 to 2013 in Monrovia, Liberia. Data obtained from clinic records included victim's age, gender and site of bite marks, site name of residence of rabies-exposed patients, promptness of care sought, initial treatment and post-exposure-prophylaxis (PEP) compliance. We computed DBV time-trend plot, seasonal index and year 2014 case forecast. Associated annual human death (AHD) was estimated using a standardized decision tree model. Of the 775 DBVs enlisted, care seeking time was within 24h of injury in 328 (42.32%) DBVs. Victim's residential location, site of bite mark, and time dependent variables were significantly associated with treatment outcome (p< 0.05). The equation X^t=28.278-0.365t models the trend of DBVs. The high (n=705, 90.97%) defaulted PEP and average 155 AHD from rabies implied urgent need for policy formulation on national programme for rabies prevention in Liberia.

Effects of Recombinant Human Bone Morphogenetic Protein-2 on Vertical Bone Augmentation in a Canine Model.

BACKGROUND: Vertical bone augmentation (VBA) remains unpredictable and challenging for most clinicians. This study aims to compare hard tissue outcomes of VBA, with and without recombinant human bone morphogenetic protein (rhBMP)-2, under space-making titanium mesh in a canine model. METHODS: Eleven male beagle dogs were used in the study. Experimental ridge defects were created to form atrophic ridges. VBA was performed via guided bone regeneration using titanium mesh and allografts. In experimental hemimandibles, rhBMP-2/absorbable collagen sponge was well mixed with allografts prior to procedures, whereas a control buffer was applied within controls. Dogs were euthanized after a 4-month healing period. Clinical and radiographic examinations were performed to assess ridge dimensional changes. In addition, specimens were used for microcomputed tomography (micro-CT) assessment and histologic analysis. RESULTS: Membrane exposure was found on five of 11 (45.5%) rhBMP-2-treated sites, whereas it was found on nine of 11 (81.8%) non-rhBMP-2-treated sites. Within 4 months of healing, rhBMP-2-treated sites showed better radiographic bone density, greater defect fill, and significantly more bone gain in ridge height (P <0.05) than controls. Experimental hemimandibles exhibited lower rates of membrane exposure and a noteworthy, ectopic bone formation above the mesh in 72% of sites. Results from micro-CT also suggested a trend of less vertical bone gain and bone mineral density in controls (P >0.05). Under light microscope, predominant lamellar patterns were found in the specimen obtained from rhBMP-2 sites. CONCLUSION: With inherent limitations of the canine model and the concern of such a demanding surgical technique, current findings suggest that the presence of rhBMP-2 in a composite graft allows an increase of vertical gain, with formation of ectopic bone over the titanium mesh in comparison with non-rhBMP-2 sites.

Efficacy of Mucograft vs Conventional Resorbable Collagen Membranes in Guided Bone Regeneration Around Standardized Calvarial Defects in Rats: An In Vivo Microcomputed Tomographic Analysis.

The aim of this in vivo microcomputed tomographic (µCT) study was to compare the efficacy of Mucograft (MG) vs resorbable collagen membranes (RCMs) in facilitating guided bone regeneration (GBR) around standardized calvarial defects in rats. Forty female Wistar albino rats with a mean age and weight of 6 to 9 weeks and 250 to 300 g, respectively, were used. With the rats under general anesthesia, the skin over the calvaria was exposed using a full-thickness flap. A standardized calvarial defect with a 4.6-mm diameter was created in the left parietal bone. For treatment, the rats were randomly divided into four groups (n = 10 per group): (1) defects covered with MG (MG group); (2) defects covered with an RCM (RCM group); (3) defects filled with xenograft bone particles and covered by MG (MG + bone group); and (4) defects filled with xenograft bone particles and covered by an RCM (RCM + bone group). Primary closure was achieved using interrupted resorbable sutures. The animals underwent high-resolution, three-dimensional µCT scans at baseline and at 2, 4, 6, and 8 weeks after the surgical procedures. Data regarding volume and bone mineral density (BMD) of newly formed bone (NFB) and bone particles revealed an increase in the volume of NFB in all the groups from baseline to 8 weeks. The MG group had the lowest volume of NFB (mean ± standard deviation [SD], 1.32 ± 0.22 mm(3)). No significant differences in mean ± SD values for volume of NFB were observed between the RCM (3.50 ± 0.24 mm(3)) and MG + bone (3.87 ± 0.36 mm(3)) groups, but their values were significantly lower than that of the RCM + bone group (2.95 ± 0.15 mm(3), F = 131.91, dfN = 2, dfD = 27, P < .001). Significant differences in BMD of NFB between the groups (F = 332.46, dfN = 3, dfD = 36, P < .001) and during different data collection periods (F = 97.04, dfN = 3, dfD = 36, P < .01) were observed, with the RCM group having the highest mean ± SD BMD of NFB (0.42 ± 0.05 g/mm(3)). Significant differences in the bone particle volume between the RCM + bone and MG + bone groups (F = 91.04, dfN = 1, dfD = 18, P < .05) and at different data collection periods (F = 314.12, P < .01) were observed, with the RCM + bone group displaying greater reduction in both volume (36.8%) and BMD (19.7%) of bone particles. The present in vivo µCT study demonstrated that RCM is better than MG in enhancing new bone formation in rat calvarial standardized defects when used in combination with mineralized particulate graft material.

Guided Bone Regeneration Using Biphasic Calcium Phosphate With Adjunct Recombinant Human Bone Morphogenetic Protein-2 With and Without Collagen Membrane in Standardized Calvarial Defects in Rats: A Histologic and Biomechanical Analysis.

This study aimed to assess the efficacy of biphasic calcium phosphate (BCP) with adjunct recombinant human bone morphogenetic protein-2 (rhBMP-2), with and without collagen membrane (CM), in regeneration of standardized rat calvarial defects. Thirty female Wistar albino rats with a mean age of 12 weeks and mean weight of 300 g were used. The skin over the calvaria was exposed using a full-thickness flap. A standardized defect measuring 4.6 mm in diameter was created in the parietal bone. The defects were randomly divided into the following groups: (1) no treatment (control group); (2) BCP soaked in rhBMP-2 and then covered with a resorbable CM; and (3) BCP soaked in rhBMP-2. Following euthanasia, histologic, histomorphometric, and biomechanical assessments of the calvarial specimens were performed to assess bone regeneration. The results showed islands of newly formed bone (NFB) between the defect edges in the control group. NFB was observed bridging the defect edges and around the remnants of BCP in the rhBMP-2 + BCP + CM group and only around the BCP remnants in the rhBMP-2 + BCP group. Histomorphometric analysis revealed a significantly higher mean ± standard deviation (SD) percentage of NFB per defect in the rhBMP-2 + BCP + CM group (46.12 ± 2.56) compared with the control (11.79 ± 0.75) and rhBMP-2 + BCP (26.65 ± 1.48) groups. Although no differences were found in the hardness and elastic modulus (EM) of NFB between the rhBMP-2 + BCP + CM (hardness: 687.78 ± 4.74 MPa; EM: 27.71 ± 0.063 GPa) and the rhBMP-2 + BCP (hardness: 637.65 ± 6.32 MPa; EM: 21.49 ± 0.095 GPa) groups, the biomechanical parameters of NFB in the control group (hardness: 286.17 ± 9.49 MPa; EM: 12.62 ± 0.048 GPa) were significantly less. The experiment demonstrated the efficiency of rhBMP-2 + BCP in GBR, wherein the presence of CM leads to a greater percentage of new bone formation within standardized calvarial defects.

Real-Time Assessment of Guided Bone Regeneration in Standardized Calvarial Defects in Rats Using Bio-Oss With and Without Collagen Membrane: An In Vivo Microcomputed Tomographic and Histologic Experiment.

In vivo microcomputed tomography (µCT) enables real-time assessment of bone regeneration. The aim of this µCT and histologic experiment was to assess guided bone regeneration (GBR) around standardized calvarial defects in rats using particulate graft material (Bio-Oss) with and without collagen membranes (CMs). Eighteen female Sprague-Dawley rats aged 6 weeks and weighing 300 g were used. With the rats under general anesthesia, calvaria were exposed and a full-thickness standardized defect was created on the parietal bone. For treatment, rats were randomly assigned to the following three groups: (1) CM group; (2) Bio-Oss group; and (3) Bio-Oss + CM group. Bone volume and bone mineral density (BMD) of newly formed bone (NFB) and remnant bone particles were measured at baseline and 2, 4, 6, and 10 weeks after the operations using real-time in vivo µCT. At 10 weeks, all animals were sacrificed and calvarial tissues were assessed histologically. In the CM group, a significant increase in mean ± standard deviation (SD) BMD of NFB was observed at 6 weeks (0.32 ± 0.02 g/mm(3)) (P < .01) compared with baseline. In the Bio-Oss group, mean ± SD volume (3.03 ± 0.14 mm(3)) (P < .05) and BMD (0.14 ± 0.01 g/mm(3)) of NFB significantly increased at 6 weeks compared with baseline (P < .01). In the Bio-Oss + CM group, mean ± SD volume (0.98 ± 0.19 mm(3)) and BMD (0.13 ± 0.01 g/mm(3)) of NFB significantly increased at 4 weeks compared with baseline (P < .01). In th Bio-Oss + CM group, mean ± SD volume (3.5 ± 0.7 mm(3)) and BMD (0.44 ± 0.03 g/mm(3)) of remnant bone particles were significantly reduced at 10 weeks compared with baseline values (5.8 ± 0.96 mm(3) and 1.3 ± 0.02 g/mm(3)) (P < .05). Although histologic analysis revealed NFB in all the study groups, the Bio-Oss + CM group exhibited the most. The results of this study revealed that, in real time, new bone formation starts as early as 4 weeks in standardized calvarial defects undergoing GBR with Bio-Oss + CM, compared with new bone formation at 6 weeks in defects undergoing GBR with Bio-Oss alone.

Bone Regeneration Using Bone Morphogenetic Protein-2 and Biphasic Calcium Phosphate With and Without Collagen Membrane in Calvarial Standardized Defects: An In Vivo Microcomputed Tomographic Experiment in Rats.

The aim of this in vivo microcomputed tomographic (µCT) experiment was to assess in real time the efficacy of a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) and biphasic calcium phosphate (BCP), with and without resorbable collagen membrane (CM), in regeneration of standardized calvarial defects (SCDs) in rats. A total of 30 female Wistar albino rats (n = 10/group) with a mean age and weight of 7.5 months and 275 g, respectively, were used. With the rats under general anesthesia, the calvaria were exposed using full-thickness periosteal flaps and unilateral SCDs of 4.6 mm diameter were created on the left parietal bone. Defects were left untreated (control group) or randomly filled with either BCP soaked in rhBMP-2 and then covered with CM (BMP + BCP + CM group) or BCP soaked in rhBMP-2 alone (BMP + BCP group). In vivo µCT scans were done at baseline and 2, 4, 6, and 8 weeks. Newly formed bone (NFB) and remaining BCP particles were assessed for their volumes (NFBV, BCPV, respectively) and mineral densities (NFBMD, BCPMD, respectively). In vivo µCT results showed scanty amounts of new bone at the peripheries of the defect in the control group. In the other two groups, near complete defect closure was evident at 8 weeks. The mean NFBV after 8 weeks was 4.63 ± 0.96 mm(3), 11.82 ± 1.17 mm(3), and 13.85 ± 1.89 mm(3) for the control, BMP + BCP + CM, and BMP + BCP groups, respectively. After 8 weeks, the mean NFBMD was 0.38 ± 0.03 g/mm(3), 0.24 ± 0.07 g/mm(3), and 0.35 ± 0.03 g/mm(3) for the control, BMP + BCP + CM, and BMP + BCP groups, respectively. After 8 weeks, the mean BCPV and BCPMD values for the BMP + BCP + CM and BMP + BCP groups were 2.73 ± 0.65 mm(3), 0.33 ± 0.08 g/mm(3), 2.49 ± 0.71 mm(3), and 0.28 ± 0.03 g/mm(3), respectively. The present real-time in vivo µCT experiment demonstrated that BMP + BCP, either with or without CM, was effective in promoting bone regeneration within rat SCDs and enabled new bone formation starting as early as 2 weeks.

Real-Time Assessment of Guided Bone Regeneration in Standardized Calvarial Defects Using a Combination of Bone Graft and Platelet-Derived Growth Factor With and Without Collagen Membrane: An In Vivo Microcomputed Tomographic and Histologic Experiment in Rats.

The aim of the present in vivo microcomputed tomography (µCT) and histologic experiment was to assess the efficacy of guided bone regeneration (GBR) around standardized calvarial defects using recombinant human platelet-derived growth factor (rhPDGF) with and without resorbable collagen membrane (RCM). A total of 50 female Wistar albino rats with a mean age of 7.5 months and mean weight of 275 g were used. The calvarium was exposed following midsagittal scalp incision and flap reflection. A full-thickness standardized calvarial defect (4.6 mm diameter) was created. Study animals were randomly divided into five groups based on biomaterials used for GBR within the defect: (1) no treatment (negative control), (2) bone graft alone (BG), (3) bone graft covered by RCM (BG + RCM), (4) bone graft soaked in rhPDGF (BG + rhPDGF), and (5) bone graft soaked in rhPDGF and covered with RCM (BG + rhPDGF + RCM). In vivo µCT for determination of newly formed bone volume (NFBV) and mineral density (NFBMD) and remnant bone particles volume (RBPV) and mineral density (RBPMD) was done at baseline and at 2, 4, 6, and 8 weeks postoperatively. Eight weeks following surgery, the animals were sacrificed and harvested calvarial specimens were subjected to histologic and biomechanical analysis. There was an increase in NFBV and NFBMD associated with a corresponding decrease in RBPV and RBPMD in all the study groups. Two-way analysis of variance revealed significant differences in the measured values within and between the groups across the timelines examined during the study period (P < .05). While the NFBV was significantly higher in the bone graft, BG + RCM, and BG + rhPDGF + RCM groups, the NFBMD was similar in all the groups except negative control. The greatest decreases in RBPV and RBPMD were observed in the BG + rhPDGF + RCM group in comparison to the other groups. Similarly, BG + rhPDGF + RCM groups had hardness and elastic modulus similar to that of natural bone. The in vivo µCT results were validated by the qualitative histologic findings. In real time, new bone formation starts as early as 2 weeks in rat calvarial defects treated with bone graft and rhPDGF, irrespective of the presence or absence of RCM.

Efficacy of Mesenchymal Stem Cells as Adjunct to Guided Bone Regeneration in Standardized Calvarial Defects in Rats: An In Vivo Microcomputed Tomographic and Histologic Analysis.

The aim of the present in vivo microcomputed tomographic (µCT), histologic, and biomechanical study was to assess the efficacy of bone marrow-derived mesenchymal stem cells (BMSCs) for promoting guided bone regeneration (GBR) in a standardized rat calvarial defect model. Forty female Wistar albino rats with a mean age of 7.5 months and mean weight of 275 g were used. Following calvarial exposure under general anesthesia, a full-thickness standardized calvarial defect (4.6 mm in diameter) was created. The study animals were randomly divided into four groups based on biomaterials used for GBR: (1) no treatment (negative control); (2) bone graft alone; (3) bone graft placed in the defect and covered with a collagen membrane (CM); and (4) bone graft soaked in BMSCs and covered with a CM. Bone volume and bone mineral density (BMD) of newly formed bone (NFB) and remnant bone particles were determined at baseline and at 2, 4, 6, 8, and 24 weeks postoperative using real time in vivo µCT. Histologic and biomechanical analyses of calvarial specimens were performed at 24 weeks, when the rats were euthanized. Statistically significant differences in volume and BMD of NFB were observed between and within the groups at different data collection periods. Significant increases in volume and BMD of NFB occurred as early as week 2 in all groups except the negative control. While the greatest volume of NFB was observed in the bone graft + BMSC + CM group, BMD of NFB was significantly higher in the bone graft + CM group. Statistically significant decreases in volume and BMD of remnant bone particles were also observed between the groups. Histologic analysis revealed NFB in all groups. The hardness and elastic modulus of NFB in the bone graft + BMSC + CM group were significantly higher than that in the other groups and also similar to adjacent natural bone. This study shows that using adjunct BMSCs with bone graft and CM for guided bone regeneration in standardized rat calvarial defects resulted in the highest quality and quantity of NFB.