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Notes: Background and objective:  The most accurate method of assessing bone level is to elevate the flap and measure the bone level directly. However, this method causes discomfort to the patient and can damage the tissues. Therefore, many studies have been conducted to find an alternative method that can be used to assess the bone level clinically with accuracy and reliability. In the present study, we evaluated the clinical reliability and accuracy of bone probing and radiographic measurements, by comparing the bone levels obtained by both of these measurement techniques with the histometrically confirmed bone levels, after four different kinds of regenerative therapy.Methods:  Twenty-four intrabony defects (4 × 4 mm one-wall intrabony defects) were surgically created bilaterally in the mandibular second and fourth premolars of six beagle dogs. The control group underwent a conventional flap operation. The graft group was treated with calcium phosphate glass only, the guided tissue regeneration group was treated with guided tissue regeneration only, and the graft + guided tissue regeneration group was treated with calcium phosphate glass and guided tissue regeneration. Bone probing and radiographic measurements were performed to assess the bone level 8 weeks after the operation and then the subjects were killed to perform the histometric measurements. The correlation between the bone probing depths and the histometric bone levels, and that between the radiographic bone levels and the histometric bone levels were analyzed by Spearman's rank correlation analysis. The statistical significance with respect to the type of regenerative therapy was analyzed by the Kruskal–Wallis test.Results:  The difference between the bone probing depth and the histometric bone level measurements was 0.14, and that between the radiographic bone level and histometric bone level was 0.6. The coefficient of correlation between the bone probing depth and the histometric bone level was 0.90, and that between the radiographic bone level and the histometric bone level was 0.73. The type of regenerative therapy had no significant effect on the difference between the histometric bone level and the other measurements.Conclusion:  The results of the present study suggest that the bone probing measurement may be a reliable method for the assessment of the actual bone level following any type of periodontal regenerative therapy.

Notes: Aim: Autogenous bone grafts and bone biomaterials are being used as part of protocols aiming at reconstruction of periodontal defects. There is a limited biologic information on the effect of such materials on periodontal healing, in particular aberrant healing events that may prevent their general use. The objective of this study was, using histological techniques, to evaluate periodontal healing with focus on root resorption and ankylosis following implantation of autogenous bone and a coral-derived biomaterial into intra-bony defects in dogs.Methods: One-wall intra-bony periodontal defects were surgically created at the distal aspect of the second and the mesial aspect of the fourth mandibular premolars in either right or left jaw quadrants in four Beagle dogs. Each animal received particulated autogenous bone and the resorbable calcium carbonate biomaterial into discrete one-wall intra-bony defects. The mucoperiosteal flaps were positioned and sutured to their pre-surgery position. The animals were euthanized 8 weeks post-surgery when block sections of the defect sites were collected and prepared for qualitative histological analysis.Results: There were no significant differences in periodontal healing between sites receiving autograft bone and the coral-derived biomaterial. A well-organized periodontal ligament bridging new bone and cementum regeneration was observed extending coronal to a notch prepared to delineate the apical extent of the defect. Osteoid and bone with enclosed osteocytes were formed onto the surface of both autograft and coral particles. Although small resorption pits were evident in most teeth, importantly none of the biomaterials provoked marked root resorption. Ankylosis was not observed.Conclusion: Particulated autogenous bone and the coral-derived biomaterial may be implanted into periodontal defects without significant healing aberrations such as root resorption and ankylosis. The histopathological evaluation suggests that the autogenous bone graft has a limited osteogenic potential as demonstrated in this study model.

Notes: Background: Previous studies suggest that a bioresorbable calcium carbonate coral implant (CI) supports space provision and bone formation for guided tissue regeneration (GTR). However, it could not be discerned whether observed effects were because of GTR or whether the CI possessed osteoconductive properties enhancing bone formation. The objective of this study was to evaluate bone formation associated with the CI biomaterial in the presence and absence of provisions for GTR.Methods: Routine, critical size, 6 mm, supra-alveolar periodontal defects were created in 12 young adult Beagle dogs. Five animals received the CI alone (Biocoral® 1000). Seven animals received the CI/GTR combination using an expanded polytetrafluoroethylene barrier (GORE-TEX® Regenerative Material). The animals were euthanized at 4 weeks postsurgery and tissue blocks of the experimental sites were collected and processed for histometric analysis.Results: Clinical healing was uneventful. The histopathologic and histometric analysis revealed significantly increased bone formation (height and area) in sites receiving the CI/GTR combination compared with CI alone (2.3±0.6 versus 1.2±0.9 mm; and 3.1±0.8 versus 1.2±1.1 mm2; p〈0.05). The CI biomaterial appeared to be mostly unassociated with new bone formation; the CI particles were observed sequestered in newly formed bone, fibrovascular marrow, and in the supra-alveolar connective tissue. Cementum formation was limited and observed in few sites for both treatment protocols.Conclusion: While GTR promoted new bone formation, the CI contributed limited, if any, osteoconductive effects.

Notes: The development of phosphate glasses for use in orthopaedic implants has attracted much interest because their chemical and physical properties make them suitable for use as bone-bonding materials. We prepared various compositions of CaO-P2O5-MO or CaO-P2O5-M2O (M: K, Li, Na, Mg, Zn) glasses to measure ion release, solubility and bioactivity. The compositions with (Ca,M)/P molarratio 0.6 were fixed P2O5 mol% content at 45.45 mol%, and varying MO or M2O mol% at 10, 20 and 30 mol%. Ca2+ ion release properties were investigated in 0.1M potassium acetate with pH 6 at 37oC by immersing 50 mg of powder into 100 ml of acidic buffer solution. The highest and lowest extent of released Ca2+ ion was observed for composition with 10 mol% of K2O and 30 mol% of MgO, respectively. The weight loss in distilled water at 37oC was measured. Solubility increased withdecreasing CaO content, but decreased with increasing MgO content. Bioactivity in the simulated body fluid at 37oC was measured

Notes: The purpose of this study was to evaluate the cell affinity of calcium phosphate glassscaffold in the system of CaO-CaF2-P2O5-MgO-ZnO, which is already reported that promoted the bone-like tissue formation in vitro and formed new bone in Sprague-Dawley rats. We prepared calcium phosphate glass saffolds with three-dimensionally interconnected pores of 200~500 µm. Commercial HA scaffold was employed as a control in this study. Bone marrow cells were collected from the healthy human donors and cultured within the prepared scaffolds. After 2, 4, 6, and 8 weeks, hMSCs/scaffold were fixed and stained with hematoxylin and eosin. hMSCs were continuously proliferated both in the experimental and control groups at every incubation period. The number of cells was higher in the experimental group than that of the control group, however, there was no significant difference (p〉0.05). Extracellular matrices could be observed at the 2nd and 4th days in theexperimental and control groups, respectively. The extracellular matrices were more abundant in the experimental group at all periods. The prepared calcium phosphate glass scaffolds are expected effective in bone tissue engineering

Notes: In tissue engineering, a scaffold helps determine 3-dimensional morphology, increases cell survival, provides initial mechanical stability, supports tissue ingrowth, aids in the formation of tissue structure. Chitosan is the partially deacetylated form of chitin that can be extracted from crustacean. It degrades in the body to non-harmful and non-toxic compounds and has been used in various fieldssuch as nutrition, metal recovery and biomaterials. Hydroxyapatite, a major inorganic component of bone, has been used extensively for biomedical implant applications and bone regeneration due to its bioactive, biodegradable and osteoconductive properties. The application, however, of hydroxyapatite is limited due to own brittleness. Since the natural bone is a composite mainly consisted of organic collagen and inorganic hydroxyapatite, many efforts have been made to modify hydroxyapatite by polymers. In this study, organic/inorganic hybrids were fabricated solid-liquid phase separation and a subsequent freeze-drying process. The microstructure, mechanical properties, and bioactivity of the scaffolds with various contents of hydroxyapatite were studied. The structure of the scaffolds prepared was macroporous and interconnected. The compressive mechanical properties such as compressive modulus and yield strength were improved according to the increase of hydroxyapatite contents mixed with chitosan. After 7 days of sample immersion in a simulated body fluid, for scaffolds containing hydroxyapatite, numerous bonelike apatites were formed on the surfaces of the pore walls. This study suggests that desirable pore structure, mechanical properties, and bioactivity of the hybrid scaffolds might be achieved through controlling the ratio of hydroxyapatite and chitosan

Notes: This present study was carried out to find out the effects of calcium aluminatecement(CaO·Al203, CAC), which has been developed with biocompatibility and mechanical properties, in biological environments. Two different particle sizes of CAC - 3.5 µm vs. 212-250 µm which is recommended in periodontal bone grafting procedures – were filled in 8mm calvarial defects in Sprague-Dawley rats. The specimens were examined histologically, especially the bone-cementinterface and the response of surrounding tissues. The result of this study shows that when calvarial defects in white rats are filled with 212-250 µm calcium aluminate cement, the materials proved to be bio-compatible in growth and healing on the surrounding tissues. When further researches on direct bone adhesion and bone regeneration ability are fulfilled, CAC is expected to be applied to various fields of periodontology in the future

Notes: Calcium sulfate used in this study is newly fabricated to overcome its disadvantages;brittleness, difficult handling properties, rapid resorption and reaction heating. Especially whencalcium sulfate is used in the graft procedure, it is difficult to control the setting time, solubility intoblood and body fluid. To improve the handling properties, Calcium sulfate is mixed withCarboxylmethylcellulose (CMS). The putty type calcium sulfate used in the present study presentedlower values in cementum formation and new bone formation than the control group. This may bedue to use of poor osteoinductive calcium sulfate alone in the defect, limiting new bone formation.In addition, complete resorption of calcium sulfate after 8 weeks presents that addition of polymerfailed to delay the resorption rate of calcium sulfate. Rather, it seemed to disturb the natural healingof the defect when compared with the findings in the control group. But the favorable result ofcalcium sulfate is shown when used with alloplast. The material used in the present study wasdeveloped for easier formability and manipulation avoiding scattering or dissolving of the materialwith blood or body fluid. However, the results reveal that further studies on effect of calciumsulfate with various other bone graft materials and ideal ratios in mixing the two should bedetermined in the future.However, the results reveal that further studies on effect of calcium sulfatewith various other bone graft materials and ideal ratios in mixing the two should be determined inthe future

Notes: The mixed pastes of binary calcium phosphate glass with Ca/P ratio of 0.6 and distilled water were set after about 4 hr, while never set when calcium phosphate glass with Ca/P lower than 0.5. Their compressive strength was ranged from 16.0 to 23.3 MPa. When Na2HPO4 solution was used instead of distilled water as liquid phase, the setting time became drastically much shorter. As the mole concentration of Na2HPO4 solution increased from 0.25 M to 2 M, setting time was shortened to 35 min from almost 3 hr, but compressive strength decreased from 28.8 MPa to 13.2MPa. At constant mole concentration, as the mass ratio of a powder to liquid ratio increased, setting time was shortened and maximum compressive strength was measured when a powder/liquid ratio was 2.5. However, no crystallized phases were detected either during setting or after complete setting.The XRD , FT-IR and SEM examinations indicated that calcium phosphate glass dissolved and then glass phase precipitated again. We concluded, therefore, that Na2HPO4 just affected the kinetics of dissolution and precipitation of CPG. The mechanism of hardening has yet to be studied

Notes: This study presents the manufacture of macroporous hydroxyapatite scaffolds with a small amount of calcium phosphate glass powder as sintering additives. Hydroxyapatite slurry was prepared by suspending the hydroxyapatite and glass powder in water. Polyurethane sponge was used to produce highly macroporous scaffolds. The rheological characteristic of the slurry was measured to identify the effect of adding calcium phosphate glass powder into hydroxyapatite slurry. Sinteredscaffolds could be repeatedly coated to improve mechanical properties. Scaffolds prepared by single and double replication cycle process were characterized by density, porosity and compressive strength measurements by increasing amount of the calcium phosphate glass powder to the hydroxyapatite slurry, viscosity by increased more than same amount of pure hydroxyapatite, and the capillary forcewas similar to pure hydroxyapatite slurry. The compressive strength of the macroporous hydroxyxapatite scaffold containing the calcium phosphate glass powder showed higher value than that of pure hydroxyapatite at single replication cycle. SEM demonstrated that the microstructure of the scaffold became denser with the introduction of the calcium phosphate glass powder. The pore struts were thicker as replication cycle was increased