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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. [ABSTRACT FROM AUTHOR]

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. Highresolution 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 STZinduced 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Guided bone regeneration (GBR) using a porcine-derived collagen matrix (Mucograft [MG], Geistlich) has not yet been reported. The aim of this histologic and biomechanical study was to compare the efficacy of MG versus resorbable collagen membranes (RCMs) in facilitating GBR around standardized rat calvarial defects. 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 4.6-mm-diameter standardized calvarial defect was created in the left parietal bone. For treatment, the rats were randomly divided into four groups (n = 10 per group): (1) MG group: the defect was covered with MG; (2) RCM group: the defect was covered with an RCM; (3) MG + bone group: the defect was filled with bone graft particles and covered by MG; and (4) RCM + bone group: the defect was filled with bone graft particles and covered by an RCM. Primary closure was achieved using interrupted resorbable sutures. The animals were sacrificed at 8 weeks after the surgical procedures. Qualitative histologic analysis and biomechanical assessment to identify hardness and elastic modulus of newly formed bone (NFB) were performed. Collected data were statistically analyzed using one-way analysis of variance. Histologic findings revealed NFB with fibrous connective tissue in all groups. The quantity of NFB was highest in the RCM + bone group. Statistically significant differences in the hardness (F = 567.69, dfN = 3, dfD = 36, P < .001) and elastic modulus (F = 294.19, dfN = 3, dfD = 36, P < .001) of NFB were found between the groups. Although the RCM + bone group had the highest mean ± standard deviation (SD) hardness of NFB (531.4 ± 24.9 MPa), the RCM group had the highest mean ± SD elastic modulus of NFB (18.63 ± 1.89 GPa). The present study demonstrated that RCMs are better than MG at enhancing new bone formation in standardized rat calvarial defects when used along with mineralized particulate graft material. [ABSTRACT FROM AUTHOR]

Guided bone regeneration (GBR) using a porcine-derived collagen matrix (Mucograft [MG], Geistlich) has not yet been reported. The aim of this histologic and biomechanical study was to compare the efficacy of MG versus resorbable collagen membranes (RCMs) in facilitating GBR around standardized rat calvarial defects. 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 4.6-mm-diameter standardized calvarial defect was created in the left parietal bone. For treatment, the rats were randomly divided into four groups (n = 10 per group): (1) MG group: the defect was covered with MG; (2) RCM group: the defect was covered with an RCM; (3) MG + bone group: the defect was filled with bone graft particles and covered by MG; and (4) RCM + bone group: the defect was filled with bone graft particles and covered by an RCM. Primary closure was achieved using interrupted resorbable sutures. The animals were sacrificed at 8 weeks after the surgical procedures. Qualitative histologic analysis and biomechanical assessment to identify hardness and elastic modulus of newly formed bone (NFB) were performed. Collected data were statistically analyzed using one-way analysis of variance. Histologic findings revealed NFB with fibrous connective tissue in all groups. The quantity of NFB was highest in the RCM + bone group. Statistically significant differences in the hardness (F = 567.69, dfN = 3, dfD = 36, P < .001) and elastic modulus (F = 294.19, dfN = 3, dfD = 36, P < .001) of NFB were found between the groups. Although the RCM + bone group had the highest mean ± standard deviation (SD) hardness of NFB (531.4 ± 24.9 MPa), the RCM group had the highest mean ± SD elastic modulus of NFB (18.63 ± 1.89 GPa). The present study demonstrated that RCMs are better than MG at enhancing new bone formation in standardized rat calvarial defects when used along with mineralized particulate graft material. [ABSTRACT FROM AUTHOR]

The goal of this investigation was to evaluate histologically and histometrically the healing process in dehiscence-type defects treated by enamel matrix derivative (EMD). Five adult female beagle dogs were used. Buccal osseous dehiscences were surgically created on the maxillary canines and the second and fourth premolars. Thirty defect sites were randomly assigned to treatment and control groups (15 defect sites for each group). The treatment group received EMD application, while the control groups received no EMD. After 4 months of healing, the dogs were sacrificed and tissue blocks were prepared. Histometric parameters were employed to evaluate the type of periodontal tissues that formed in the defects. All created dehiscence defects in the test sites treated by EMD had formed functional connective tissue fibers inserted into regenerated cellular cementum. The mean amount of apicocoronal regenerated cementum was 3.74 ± 0.43 mm in EMDtreated sites, whereas the control sites had not formed cementum in the created dehiscence defects (P < .000). Statistically significant differences were found between treatment and control sites. Within the limits of this study, it can be concluded that EMD alone effectively promoted new cementum and functionally oriented connective tissue formation. [ABSTRACT FROM AUTHOR]

- This experiment assessed the efficacy of the enamel matrix derivative (EMD) to regenerate cementum in vital and endodontically treated teeth with osseous dehiscence defects. Five adult female beagle dogs were used. Thirty maxillary teeth (bilateral maxillary canines and second and fourth premolars) were randomly divided into two experimental groups (groups A and B, containing 12 teeth each) and one control group (group C). Endodontic treatment was only performed on teeth in group A compared with teeth in groups B and C. Buccal osseous dehiscence defects were surgically created in teeth from all groups. Teeth in the experimental group were treated with the EMD, whereas the controls were not. After 5 months, the animals were sacrificed and block sections of the teeth in experimental and control groups were processed for histological analysis. Newly regenerated cementum was observed in all teeth in groups A and B. No cementum regeneration was observed in group C. There was a significant difference in cementum generation between the experimental and control groups ( P < 0.001). EMD therapy induces cementogenesis in vital and endodontically treated teeth with osseous dehiscence defects. [ABSTRACT FROM AUTHOR]