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Background and Objectives: The current study aimed to compare the extent of bone growth achieved after guided tissue regeneration (GTR) based on the location and nature of the initial periodontal lesion. Materials and Methods: The study sample included 80 patients who underwent GTR at Kyungpook National University Dental Hospital since 2012 and were radiologically followed up for at least 2 years after treatment. The patients were divided into four groups based on the location (maxilla and mandible) and nature (furcation involvement and intrabony defects) of the lesion. Differences in bone levels before and after treatment were analyzed. Additionally, a comparison of outcomes based on the type of bone graft material used was conducted. Statistical analysis included a comparison of groups using a t-test, assuming equal variance. Results: The proportion of bone growth observed in the maxillary furcation, mandibular furcation, maxillary intrabony, and mandibular intrabony lesions was 26%, 22%, 31%, and 34%, respectively. No statistically significant differences in the amount of bone fill were observed between the groups. However, a significant positive correlation was found between the initial depth of the bone defect and the amount of bone fill observed after treatment. Conclusions: Contrary to previous evidence, the current study observed no significant differences in the amount of bone fill after GTR based on the location and nature of the lesion. Furthermore, the amount of bone regenerated was directly proportional to the initial depth of the alveolar bone defect. [ABSTRACT FROM AUTHOR]

Lipid biosynthesis is recently studied its functions in a range of cellular physiology including differentiation and regeneration. However, it still remains to be elucidated in its precise function. To reveal this, we evaluated the roles of lysophosphatidic acid (LPA) signaling in alveolar bone formation using the LPA type 2 receptor (LPAR2) antagonist AMG‐35 (Amgen Compound 35) using tooth loss without periodontal disease model which would be caused by trauma and usually requires a dental implant to restore masticatory function. In this study, in vitro cell culture experiments in osteoblasts and periodontal ligament fibroblasts revealed cell type‐specific responses, with AMG‐35 modulating osteogenic differentiation in osteoblasts in vitro. To confirm the in vivo results, we employed a mouse model of tooth loss without periodontal disease. Five to 10 days after tooth extraction, AMG‐35 facilitated bone formation in the tooth root socket as measured by immunohistochemistry for differentiation markers KI67, Osteocalcin, Periostin, RUNX2, transforming growth factor beta 1 (TGF‐β1) and SMAD2/3. The increased expression and the localization of these proteins suggest that AMG‐35 elicits osteoblast differentiation through TGF‐β1 and SMAD2/3 signaling. These results indicate that LPAR2/TGF‐β1/SMAD2/3 represents a new signaling pathway in alveolar bone formation and that local application of AMG‐35 in traumatic tooth loss can be used to facilitate bone regeneration and healing for further clinical treatment. [ABSTRACT FROM AUTHOR]

Background and Objectives: The purpose of this study is to assess the long-term maintenance of each approach of sinus elevation, the crestal approach and lateral approach, by comparing the radiographic results of each technique. Materials and Methods: In total, 103 patients who had undergone an implant procedure with either the crestal approach or lateral approach method applied to their maxillary molar edentulous area were included. Using orthopantomographs, the radiographic changes were consistently evaluated over 3 years after the procedure (immediately after procedure and 1 year, 2 years and 3 years after implant placement) Results: The radiographic evaluation after 3 years of implantation with sinus elevation showed a significant amount of bone formation (8.07 mm for crestal approach and 12.00 mm for lateral approach method). The largest amount of grafted height loss occurred during the 1 year, but the resorption was minimal (0.98 mm for crestal approach and 0.95 mm for lateral approach method) over the entire 3 years. Conclusions: Although the lateral approach showed more bone growth, the amount of bone resorption was similar to that of the crestal approach. Both methods showed the highest amount of bone resorption in the first year, and the amount of change thereafter was insignificant. It is judged that both methods can be used according to the situation to help implant placement. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of resveratrol on periodontal bone regeneration after local delivery and to determine its effect on inflammatory mediators. Background: Resveratrol is considered an anti‐inflammatory polyphenolic stilbene involved in the modulation of inflammation. Materials and Methods: Periodontitis was induced in mouse molars using a 5‐day ligature model followed by the left second molar extraction and 50 µM resveratrol treatment for 1 and 2 weeks. We then examined specimens treated for 1 week histologically and with immunostaining. Microfocus‐computed tomography (micro‐CT) was used to examine the bone volume formation. Results: After 1 week of treatment, proinflammatory cytokine levels (TNF‐alpha and IL6), cells exhibiting neutrophil and macrophage marker (MPO), cell proliferation marker (Ki67), and preosteoblastic marker (RUNX2) reactivity decreased in the resveratrol‐treated specimens compared to the control group. In contrast, we observed a higher number of CD31‐, F4/80‐, and osteocalcin‐ (OCN‐) positive cells in the resveratrol‐treated specimens. After 2 weeks, micro‐CT confirmed an increased bone mass in the region of the extraction socket in the resveratrol‐treated group. Conclusion: After 1 week, the resveratrol‐treated specimens revealed evidence of inflammation modulation compared to the control group. These data suggest that resveratrol not only affects inflammation control but also is useful for treating periodontitis‐related tissue defects and bone regeneration. [ABSTRACT FROM AUTHOR]

Background and Objective: After tooth extraction, the extraction socket undergoes several steps of soft and hard tissue healing. The healing process of the extraction socket is modulated by a range of signaling factors and biochemical agents. It has been reported that resveratrol, a polyphenolic compound, exhibits various biological effects, including anti‐inflammatory, anti‐carcinogenic, antioxidant, and anti‐aging effects, and protects cardiovascular and bone tissues. In this study, we examined the cellular effects of resveratrol on human periodontal ligament (hPDL) cells and osteoblast‐like (MC3T3‐E1) cells and evaluated the bone‐healing capacity of tooth extraction sockets in mice. Material and Methods: Resveratrol was applied to hPDL and MC3T3‐E1 cells to detect cell proliferation and alkaline phosphatase (ALP) activity, and qPCR was employed to understand the gene expression level in vitro. For in vivo experiment, six‐week‐old C57BL/6 male mice were randomly divided into control (n = 15) and experimental (n = 15) groups and maxillary first molars were extracted by surgery. Experimental groups received 50‐µM resveratrol on extraction sockets and analyzed the degree of new bone formation. Results: Treatment of hPDL and MC3T3‐E1 cells with resveratrol increased the cell proliferation and ALP activity and enhanced the expression of ALP, BMP‐2, BMP‐4, and OC genes. Resveratrol enhanced new bone formation in the lingual extraction socket in mice. Conclusion: These results suggest that resveratrol increases the cellular physiology of PDL and osteoblast including their proliferation and differentiation and may play an important role in bone‐healing capacity after tooth extraction. [ABSTRACT FROM AUTHOR]

Objective: We evaluated the role of oleanolic acid acetate (OAA), a triterpenoid commonly used in the treatment of liver disorders, inflammatory diseases, and metastasis, in bone formation after tooth loss by periodontitis. Background: Periodontitis causes the sequential degradation of the alveolar bone and associated structures, resulting in tooth loss. Several studies have attempted to regenerate the bone for implantation following tooth loss. Methods: Maxillary left second molar was extracted from 8‐week‐old male mice following induction of periodontitis by ligature for 5 days. The extraction socket was treated with 50 ng/µL OAA for 1, 2, and 3 weeks. Detailed morphological changes were examined using Masson's trichrome staining, and the precise localization patterns of various signaling molecules, including CD31, F4/80, interleukin (IL)‐6, and osteocalcin, were observed. The volume of bone formation was examined by Micro‐CT. Osteoclasts were enumerated using tartrate‐resistant acid phosphatase (TRAP) staining. For molecular dissection of signaling molecules, we employed the hanging‐drop in vitro cultivation method at E14 for 1 day and examined the expression pattern of transforming growth factor (TGF)‐β superfamily and Wnt signaling genes. Results: Histomorphometrical examinations showed facilitated bone formation in the extraction socket following OAA treatment. In addition, OAA‐treated specimens showed the altered localization patterns of inflammatory and bone formation‐related signaling molecules including CD31, F4/80, IL‐6, and osteocalcin. Also, embryonic tooth germ mesenchymal tissue cultivation with OAA treatment showed the significant altered expression patterns of signaling molecules such as transforming growth factor (TGF)‐β superfamily and Wnt signaling. Conclusions: Oleanolic acid acetate induces bone formation and remodeling through proper modulation of osteoblast, osteoclast, and inflammation with regulations of TGF‐β and Wnt signaling. [ABSTRACT FROM AUTHOR]

Purpose: Hydroxyapatite treated with recombinant human bone morphogenetic protein-2/Hydroxyapatite (rhBMP-2/HA) or bovine bone was applied on extraction sockets for alveolar ridge preservation, and the results were compared with respect to clinical and histological bone formation. Materials and Methods: This was a prospective, randomized controlled clinical trial performed on 20 implant placement sites (10 in the experimental and 10 in the control group). rhBMP-2/HA was applied on extraction sockets in the experimental group and bovine bone on those of the control group. The bone at the corresponding sites was biopsied 3 months later, and clinical, histological, and histomorphometric analyses were performed. Results: The alveolar bone height was well preserved in both groups with relatively less change in width in the experimental group compared with the control group. The percentage of new bone was 25.37% ± 17.23% in the experimental group and 6.13% ± 4.32% in the control group; the difference was statistically significant. Conclusions: The alveolar ridge was preserved clinically and histologically in both groups. rhBMP-2/HA resulted in greater new bone formation than bovine bone 3 months after the surgery. [ABSTRACT FROM AUTHOR]

Background: Although increasing evidence indicates that serotonin (SER; 5-hydroxytrypamine [5-HT]) is involved in the regulation of bone metabolism, conflicting data exist regarding whether SER promotes or inhibits osteoblast differentiation and bone formation. Regeneration of functional bone is required for proper osseointegration of dental implants. Noticeably, the use of selective SER reuptake inhibitors was recently associated with the failure of osseointegrated dental implants. The present study examines the direct role of peripheral SER on the regulation of bone regeneration.Methods: The effect of SER on osteoblast differentiation and bone regeneration was examined using rat calvarial cell cultures in vitro and a rat critical-sized calvarial defect model in vivo.Results: Rat calvarial cells expressed SER receptors Htr1 (5-HT1) and Htr2 (5-HT2), which are known to transmit signals in bone cells. In vitro, SER significantly reduced osteogenic differentiation and mineralization of rat calvarial cells with concomitant reduction of osteoblast marker genes including alkaline phosphatase (Alpl), osterix (Sp7), and osteocalcin (Bglap). Histologic and radiologic analyses using the rat critical-sized calvarial defect model revealed that the existence of SER significantly inhibited β-phase tricalcium phosphate-induced bone regeneration.Conclusion: Results suggest that SER in the local bone microenvironment might play a negative role in osteoblast differentiation and bone formation in rats. [ABSTRACT FROM AUTHOR]

Objective: This histomorphometric study compared the efficacy of a new bone graft substitute (N-HA) derived from hen eggshell, consisted of submicron scale porous hydroxyapatite structure, in the healing of 8 mm diameter critical size defects in rat calvaria. We compared N-HA alone or in combination with calcium sulfate (CS), with a commercial bone substitute, anorganic bovine bone (Bio-Oss, BO). Material and methods: Critical size defects were created in calvaria of 56 adult Sprague–Dawley rats. Animals were divided into four groups and treated with (1) unfilled defects, (2) N-HA grafts, (3) BO grafts and (4) N-HA/CS grafts. The percentage of new bone formed (NB%) was evaluated histomorphometrically after 6 and 12 weeks. Results: The N-HA group exhibited more new bone formation compared with other groups at 6 and 12 weeks. Histomorphometric analysis showed greater NB% in N-HA group (11.2% at 4 weeks and 19.2% at 12 weeks) compared with those in unfilled (3.9% at 6 weeks and 6.4% at 12 weeks), BO-treated (6.4% at 6 weeks and 8.2% at 12 weeks) and N-HA/CS-treated (6.3% at 6 weeks and 12.6% at 12 weeks) groups. The N-HA group showed significant differences in NB% compared with unfilled group at 6 weeks ( P=0.016), unfilled and BO-treated groups at 12 weeks ( P=0.001). The addition of CS did not enhance the NB% compared with defects grafted with N-HA alone. Conclusion: N-HA was an osteoconductive bone substitute for treating osseous defects in critical size defects of rat calvaria. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of the addition of oxide structure with submicron‐scale porous morphology on the periimplant bone response around titanium (Ti) implants with microroughened surfaces. Hydroxyapatite‐blasted Ti implants with (experimental) and without (control) a porous oxide structure produced by chemical treatment were investigated in a rabbit femur model. Surface characterizations and in vivo bone response at 4 and 8 weeks after implantation were compared. The experimental implants had submicron‐scale porous surface structure consisted of anatase and rutile phase, and the original Ra values produced by blasting were preserved. The histomorphometric evaluation demonstrated statistically significantly increased bone‐to‐implant contact (BIC) for experimental implants, both in the three best consecutive threads (p < 0.01) and all threads (p < 0.05) at 4 weeks. There was no remarkable difference in the BIC% or bone area percentage between the two groups at 8 weeks. The porous Ti oxide surface enhanced periimplant bone formation around the Ti implants with microroughened surfaces at the early healing stage. Based on the results of this study, the addition of crystalline Ti oxide surface with submicron‐sized porous morphology produced by chemical treatment may be an effective approach for enhancing the osseointegration of Ti implants with microroughened surfaces by increasing early bone‐implant contact. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008 [ABSTRACT FROM AUTHOR]