• Journal of Periodontal and Implant Science
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• v.53 no.4
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• pp.306-317
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• 2023

Purpose: Biphasic calcium phosphate (BCP), a widely used biomaterial for bone regeneration, contains synthetic hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), the ratio of which can be adjusted to modulate the rate of degradation. The aim of this study was to evaluate the clinical and radiographic benefits of reconstructing peri-implant bone defects with a newly developed BCP consisting of 60% β-TCP and 40% HA compared to demineralized bovine bone mineral (DBBM). Methods: This prospective, multicenter, parallel, single-blind randomized controlled trial was conducted at the periodontology departments of 3 different dental hospitals. Changes in clinical (defect width and height) and radiographic (augmented horizontal bone thickness) parameters were measured between implant surgery with guided bone regeneration (GBR) and re-entry surgery. Postoperative discomfort (severity and duration of pain and swelling) and early soft-tissue wound healing (dehiscence and inflammation) were also assessed. Data were compared between the BCP (test) and DBBM (control) groups using the independent t-test and the χ² test. Results: Of the 53 cases included, 27 were in the test group and 26 were in the control group. After a healing period of 18 weeks, the full and mean resolution of buccal dehiscence defects were 59.3% (n=16) and 71.3% in the test group and 42.3% (n=11) and 57.9% in the control group, respectively. There were no significant differences between the groups in terms of the change in mean horizontal bone augmentation (test group: -0.50±0.66 mm vs. control groups: -0.66±0.83 mm, P=0.133), postoperative discomfort, or early wound healing. No adverse or fatal complications occurred in either group. Conclusions: The GBR procedure with the newly developed BCP showed favorable clinical, radiographic, postoperative discomfort-related, and early wound healing outcomes for peri-implant dehiscence defects that were similar to those for DBBM.

• Journal of dental hygiene science
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• v.16 no.2
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• pp.176-182
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• 2016

The purpose of this study was to evaluate the in-vitro efficacy of the active ingredients of dentifrice following treatment time. The whitening effect was evaluated by a change in lightness value relative to the contact time of hydrogen peroxide, by using artificially stained hydroxyapatite discs. The anti-calculus effect was assessed based on the amount of calcium eluted from the human dental calculus by sodium pyrophosphate. Remineralization was evaluated by the Vickers hardness test following the application of sodium fluoride to bovine enamel. In order to view dentinal tubules occlusion, the formation of insoluble calcium salts by bovine dentin specimens was observed using scanning electron microscopy. Change in lightness value (${\Delta}L$) was $5.50{\pm}1.51$ after 1 min of treatment, $5.73{\pm}0.43$ after 3 min, $8.64{\pm}0.24$ after 10 min, $18.93{\pm}0.76$ after 30 min, and $27.35{\pm}0.54$ after 60 min. The amount of calcium eluted from the human dental calculus was $4.23{\pm}0.14ppm$ after 1 min of treatment, $4.51{\pm}0.04ppm$ after 3 min, $12.12{\pm}0.16ppm$ after 10 min, $17.85{\pm}0.81ppm$ after 30 min, and $25.15{\pm}0.32ppm$ after 60 min. The Vickers hardness change value (${\Delta}VHN$) was $1.96{\pm}1.44$ after 1 min, $1.52{\pm}1.06$ after 3 min, $9.06{\pm}0.15$ after 10 min, $10.83{\pm}5.13$ after 30 min, and $12.55{\pm}2.09$ after 60 min. Partial dentinal tubules occlusion was observed at 10 min and complete occlusion was evident at 60 min. In summary, the use of patch type dentifrices for 10, 30, or 60 min were 1.57 to 8.26 times more effective than using the paste type dentifrices for 1 to 3 min. Based on these findings, it is reasonable to expect that the use of patch type dentifrices for 10 min would lead to remineralization, anti-calculus and dentinal tubules occlusion effects, and that use for 30 min would result in a whitening effect.

• Journal of dental hygiene science
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• v.11 no.5
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• pp.405-410
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• 2011

The aim of this study was to evaluate antibacterial effect of Cl coated titanium. To coat the Cl on the titanium, first, the titanium was modified by blasting treatment with hydroxyapatite and alumina powder. Anodization process was completed using electrolyte solution of 0.04 M ${\beta}$-glycerol phosphate disodium salt n-hydrate, 0.4 M calcium acetate n-hydrate and 1 M NaCl on the condition of 250 voltages for 3 min. Surface morphology and elements' observation were performed with scanning electron microscopy and energy dispersive spectroscopy and surface profiler was used to analyze the surface roughness. Antibacterial effect was evaluated by film adhesion method. The anodized titanium after blasting showed dimpled surface contained the Cl. Surface average roughness of these surfaces had significantly higher compared to polished titanium. Result of antibacterial test showed that anodized titanium after blasting had an enhanced antibacterial effect compared to the polished titanium. Therefore, these results suggested that titanium contained Cl by anodization after blasting had a rough surface as well as antibacterial effect.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.9
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• pp.879-886
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• 2010

This study investigated the removal characteristics of highly concentrated $NH_4$-N and $PO_4$-P by struvite crystallization using converter slag as a seed crystal. The optimal pH range for removal and recovery of $NH_4$-N and $PO_4$-P by struvite crystallization was measured to be 8.0~8.75, in which total removal efficiencies for $NH_4$-N and $PO_4$-P by struvite precipitation and crystallization were 34.3~61.0% and 91.0~96.2%, respectively. The maximum removal efficiencies for $NH_4$-N and $PO_4$-P by struvite crystallization were 29.4% at pH 8.5 and 65.1% at pH 8.0, respectively. The removal efficiency of $NH_4$-N by struvite crystallization decreased with increasing calcium ion concentration. The analysis results of SEM, EDS and XRD exhibited that $NH_4$-N and $PO_4$-P in meta-stable region of struvite crystallization could be eliminated through formation of magnesium ammonia phosphate (MAP) and hydroxyapatite (HAp) on seed crystals by struvite precipitation and crystallization.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.6
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• pp.485-493
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• 2007

Introduction: Although several types of calcium-phosphate coumpound have been frequently applied to osseous defects at maxillofacial area for many years, there is a controversy about its efficiency on bone conductivity comprared to xenograft bone substitute. Alloplastic carbonapatite has been introduced to improve disadvantages of hydroxyapatite and to mimic natural bone containing carbon elements. However, a preclinical study about its efficiency of osteoconductivity has not been reported. This study was performed to evaluate the early osteoconductive potential of synthetic carbonapatite with multiple pores relative to anorganic bovine xenograft. Materials and methods: Total 5 beagle dogs were used for maxillary augmentation model. The control (anorganic bovine xenograft) and experimental groups (synthetic carbonapatite) were randomly distributed in the mouth split design. After bone graft, all animals were sacrificed 4 weeks after surgery. Histological specimens with Masson Trichrome staining were made and histomorphometrically analysed with image analyser. The statistical analysis was performed using paired t-test. Results: In both groups, all animals had no complications. The experimental group showed relatively much new bone formation around and along the bone substitutes, whereas it was clearly reduced in the control group. The ratios of new bone area to total area, to material area and to the residual area excluding materials were higher in the experimental group ($0.13{\pm}0.03,\;0.40{\pm}0.13,\;0.20{\pm}0.06$ respectively) than in the control group ($0.01{\pm}0.01,\;0.03{\pm}0.02,\;0.03{\pm}0.03$, respectively). And the differences between both groups were statistically significant (p<0.001, <0.01, <0.01, respectively), while the ratio of material area to total area in two groups was not significant. Conclusion: Carbonapatite showed a high osteoconductivity in the early stage of bone healing compared to bovine derived anorganic bone substitute. This study suggests that this bone materials can be applied as a reliable bone substitute in the clinical treatment.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.155-161
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• 2017

Teeth and bones are highly mineralized tissues containing inorganic minerals such as calcium phosphate, and a growing number of evidences show that their mineral content is associated with many diseases. Although the quantification of mineral contents by micro-computed tomography(micro- CT) has been used in diagnosis and evaluation for treating bone diseases, its application for teeth diseases has not been well established. In this study, we attempted to estimate a usefulness of a high-resolution micro-CT in analysis of human teeth. The teeth were scanned by using the Skyscan 1172 micro-CT. In order to measure tooth mineral content, beam hardening effect of the machine was corrected with a radiopaque iodine-containing substance, iodoacetamide. Under the maximum resolution of $6.6{\mu}m$, X-ray densities in teeth and hydroxyapatite standards were obtained with Hounsfield unit (HU), and they were then converted to an absolute mineral concentration by a CT Analyzer software. In enamel layer of cusp area, the mean mineral concentration was about $2.14mg/mm^3$ and there was a constant mineral concentration gradient from the enamel surface to the dentinoenamel junction. In the dentin of middle 1/3 of tooth, the mean mineral concentration was approximately $1.27mg/mm^3$ and there was a constant mineral concentration gradient from the outer of root to the pulp side, ranging from 1.3 to $1.06mg/mm^3$. In decay region of dentin, the mineral content was gradually decreased from the intact inner side to the decayed surface. These results suggest that high-resolution micro-CT can be as a useful tool for non-invasive measurement of mineral concentration in teeth.

• Journal of Soil and Groundwater Environment
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• v.21 no.1
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• pp.28-39
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• 2016

Struvite (MgNH₄PO₄ ⋅ 6H₂O) and hydroxyapatite (HAP, Ca₁₀(PO₄)₆(OH)₂) precipitation in urine-separating toilets (NoMix toilets) causes severe maintenance problems and also reduce the phosphate and calcium content. Application of urine separating technique and extraction of by-products from human urine is a cost effective technique in waste water treatment. In this study, we extract urine calcite from human urine by batch scale method, using urease producing microbes to trigger the precipitation and calcite formation process. Extracted urine calcite (calcining at 800℃) is a potential adsorbent for removal of heavy metal(loid)s like (Cd²⁺, Cu²⁺, Ni²⁺, Pb²⁺, Zn²⁺ and As³⁺) along with additional leaching analysis of total nitrogen (T-N), phosphate (T-P) and chemical oxygen demand (COD). The transformations of calcite during synthesis were confirm by characterization using XRD, SEM-EDAX and FT-IR techniques. In additional, the phosphate leaching potential and adsorbate (nitrate) efficiency in aqueous solution was investigated using the calcinedurine calcite. The results indicate that the calcite was effectively remove heavy metal(loid)s lead up to 96.8%. In addition, the adsorption capacity (q_e) of calcite was calculated and it was found to be 203.64 Pb, 110.96 Cd, 96.02 Zn, 104.2 As, 149.54 Cu and 162.68 Ni mg/g, respectively. Hence, we suggest that the calcite obtain from the human urine will be a suitable absorbent for heavy metal(loid)s removal from aqueous solution.