Study On Degradation Of Different Replacement Rates Of Coral Hydroxyapatite In Vitro

BackgroundBecause of clinical cancer, periodontal disease, periapical inflammation and other reasons, these diseases caused a wide range of alveolar bone defects which can not repair themselves in some patients. Autogenous bone graft has been accepted the gold standard in bone defect [1], but because of donor site limitation, surgery may be necessary to open a second area, bring the additional pain, damage and the chance of infection to the patients, therefore it still does not have been widely applied clinically. The useing of artificial bone substitute materials has become one of the options for repairing bone defects, commonly BDHA (Bovine-Derived Hydroxyapatite, BDHA)has been used in clinical as the repairing bone defect as the commonly useful materials, it has been widely used in various due to periodontal disease, trauma and inflammation bone defects.This bone substitute material has good biocompatibility and osteoconductive. Studies have shown that DBHA has a slowly absorbed,can be a good supporting role when the bone substitute material, and does not affect normal bone tissue healing, and even to some extent, can promote the formation of new bone. [2,3] But because of its expensive,complex production process and the limited number of coverage, the clinical application is still subject to certain restrictions. Therefore, many researchers are actively looking for other coverage simple, some simple production process of bone substitute material.Coral bone hydroxyapatite (coralline hydroxyapatite, CHA), also known as coralline hydroxyapatite (hydroxyapatite/coralline, HA/coral) is artificial biodegradable material which replaced calcium carbonate in the coral to the to hydroxyapatite by hydrothermal replacement, retain the porous structure of coral, while having a bone guide, biocompatibility, mechanical strength, etc. like hydroxyapatite, has been widely used in clinical. But long-term clinical observation also found that the current CHA in maxillofacial bone defects used are low replacement rate CHA (replacement rate of 10%-15%),.Low replacement rate CHA has a rapid degradation in the body. Not until the new bone formed the body has absorbed most of the bone substitute material,which is still insufficient for bone morphogenic area for long-term maintenance. If the absorption rate of degradation can be further coordinated with the formation of new bone remodeling rate, it can improve the artificial bone material with autologous bone tissue replacement and renovation process better.Coral hydroxyapatite bone preparation through the coral is formed through hydrothermal exchange reaction. Hydrothermal exchange reaction starting with the surface of the material. The length of the transition time, transition temperature low, the conversion of different depths, can affect the coral skeleton generative thickness of hydroxyapatite, calcium carbonate, and the formation of different proportions of hydroxyapatite bone substitute materials. Since the bone defect, coralline hydroxyapatite calcium carbonate degraded faster than hydroxyapatite degradation rate is slow, it can be replaced by adjusting the ratio of hydroxyapatite can form different hydroxyapatite and carbonate the proportion of calcium bone substitute material, the formation of different degradation rate of the artificial bone meal. After the replacement rate and the increase, the main component of bone coral hydroxyapatite bone substitute material is hydroxyapatite, which is the same as the current clinical allograft commonly used inorganic calf bone is the main component, is expected to meet the clinical long efficient to maintain bone morphogenetic requirements. As bone substitutes to repair bone defects provides a new choice. At present study, the high replacement rate of bone coral hydroxyapatite applied maxillofacial bone defect is no report, the high replacement rate of coral bone hydroxyapatite as a bone substitute material can be applied for an in-depth study should Mandibular Defects.In this study, a simple replacement rate of in vitro degradation of different coral hydroxyapatite bone, aimed at removing a variety of complex conditions of the complex in vivo environment of interference degradation bone substitute material, a simple comparison of different bone replacement rate of coral hydroxyapatite stone degradation in relatively stable buffer capacity, and generate forms and materials degradation products of degradation after the change, provide the basis for different replacement rates of coralline hydroxyapatite animal experiments and clinical application.purpose1. Different replacement rate of coralline hydroxyapatite in vitro degradation rate;2. Ion composition different replacement rate after in vitro degradation of coral hydroxyapatite formation;3. Detection of different morphology replacement rate hydroxy apatite in vitro after degradation.method1. The different rates of coralline hydroxyapatite replacement packet, the replacement rate of 10% -15% of the CHA group is set to 1, the replacement rate of> 95% of the CHA 2 is set to control group calf inorganic bone set into three groups, each group press degradation time Ow,2w,4w,8w,16w divided into five queues. Each group of materials 0.3g (±0.0010) were placed in serum 100ml bottle, add 50ml 0.1M pH7.4 Tris-HCl buffer, placed in a constant temperature shaker at 37± 1℃,2Hz frequency shock degradation. In Ow,2w,4w,8w, when 16w, each set corresponding to the group material is removed, heated oven dried, weighed on electronic scales. Were recorded under Ow,2w,4w,8w,16w weight loss of the sample.2. Measurement of degradation products2.1 with ammonium molybdate spectrophotometric measurement of material degradation after degradation buffer total phosphorus content2.2 Absorption Spectroscopy after content material degradation buffer degradable calcium metal ions by flame atomic3. Scanning electron microscopy of different materials in the degradation of surface morphology changes in different periods to compare their surface morphology, pore size and shape change microscopic crystals change; the use of X-ray diffraction (X-ray diffraction, XRD) and phase monitoring analysis of different surface materials degradation during crystal phase.resultAfter 16 weeks degradation the CHA with Low replacement rate in vitro,the weight loss was 52.68%, the CHA with high replacement rate in vitro,the weight loss was -1.51%, as a control group Bovine-Derived Hydroxyapatite after 16 weeks degradation in vitro the weight loss was 1.41%. Low replacement rate CHA weightlessness rate ANOVA results:p= 0.00<0.05, there were significant differences between every time points. High replacement rate CHA weightlessness rate ANOVA results:P=0.193> 0.05 means no differences at all time points. BDHA weightlessness ANOVA results:P=0.333> 0.05. There is no difference at all time points. It can be seen from the statistical analysis, there are significant differences in weight loss in each time point of the low substitution rates CHA, no significant differences in each time point of HCHA and BDHA, the weight loss.It can be seen that durning the 16 weeks degradation, low replacement rate CHA had undergone significant degradation, while BDHA and high degradation rate CHA had not significant degradation.The low replacement rate of CHA had a independent samples t-test between 2 weeks and 16 weeks, the result is:LCHA1 and LCHA5 are heterogeneity of variance, t=-14.333, p= 0.005<0.05, described the 16 weeks LCHA and the 2 weeks LCHA had significant difference.The 16 weeks was significantly less than the 2 weeks sample.The high replacement rate of CHA had a independent samples t-test between 2 weeks and 16 weeks, the result is:HCHA1 and HCHA5 are homogeneity of variance, t=-2.275, p= 0.085> 0.05, described the 16 weeks HCHA and the 2 weeks HCHA had no significant difference in the quality of the sample.The 16 weeks and the 2 weeks sample were not very different.Bone hydroxyapatite in the second week and 16 weeks a sample of material quality independent samples t-test, the result is:BDHA1 and BDHA5 heterogeneity of variance, t=-2.190, p= 0.094> 0.05, described the 16 weeks BDHA and the 2 weeks BDHA had no significant difference in the quality of the sample.The 16 weeks and the 2 weeks sample were not very different.Among the experimental group statistics show that:The low replacement rate CHA with BDHA statistics normally distributed at 16 weeks, Levene’s test to check the homogeneity of variance, independent sample t test results:t= 15.874, P= 0.004 < 0.05, the difference was statistically significant. High replacement rate CHA and BDHA statistics normally distributed, Levene’s test to check the homogeneity of variance, independent sample t test results:t=-5.338, P= 0.006<0.05.The difference was statistically significant. Low replacement rate and high replacement rate CHA statistics normally distributed, Levene’s test to check the homogeneity of variance. Independent sample t test results:t= 16.685, P= 0.003<0.05.The difference was statistically significant. Statistical results can be seen above, the degradation rate of Low replacement rate CHA was significantly higher than the high replacement rate CHA and the DBHA. And the degradation rate of high replacement rate CHA and DBHA are not the same, high replacement rate CHA degradation the rate is lower than the DBHA.2. Buffer element content measurements2.1 With ammonium molybdate spectrophotometric we measured the buffer used by low replacement rate coralline hydroxyapatite degradation total phosphorus content of 0.458mg/L.The high replacement rate of coralline hydroxyapatite degradated buffer total phosphorus content of 2.895mg/L. The BDHA degradated buffer total phosphorus content of 3.143mg/L.2.2 By flame atomic absorption spectrometry we measured the buffer used by low replacement rate coralline hydroxyapatite degradated content of calcium 340.6mg /L, the buffer used by high replacement rate coralline hydroxyapatite degradated content of calcium 4.148mg/L,the buffer after the degradation of the BDHA content of calcium 6.108mg/L.At 8 weeks, the statistical results of calcium levels among the groups accorded with normal distribution. Levene’s test checked the homogeneity of variance. We do the independent samples t-test between low replacement rate of coral hydroxyapatite and bovine-derived hydroxyapatite the calcium ion statistics for independent samples t-test t= 79.558, P=0.000<0.05.At 8 week,the calcium content of low replacement rate CHA and bovine-derived hydroxyapatite had statistically significant. We do the independent samples t-test between high replacement rate of coral hydroxyapatite and bovine-derived hydroxyapatite the calcium ion statistics for independent samples t-test t=-5.171, P=0.007<0.05.At 8 week,the calcium content of low replacement rate CHA and bovine-derived hydroxyapatite had statistically significant. We do the independent samples t-test between low replacement rate of coral hydroxyapatite and low replacement rate of coral hydroxyapatite the calcium ion statistics for independent samples t-test t= 79.748, P=0.000<0.05.At 8 week,the calcium content of low replacement rate CHA and low replacement rate of coral hydroxyapatite had statistically significant.At 8 weeks, the statistical results of phosphorus levels among the groups accorded with normal distribution. Levene’s test checked the homogeneity of variance. We do the independent samples t-test between low replacement rate of coral hydroxyapatite and bovine-derived hydroxyapatite the phosphorus statistics for independent samples t-test t=79.558, P=0.000<0.05.At 8 week,the phosphorus content of low replacement rate CHA and bovine-derived hydroxyapatite had statistically significant. We do the independent samples t-test between high replacement rate of coral hydroxyapatite and bovine-derived hydroxyapatite the phosphorus statistics for independent samples t-test t=-5.171,P= 0.007<0.05.At 8 week,the calcium content of low replacement rate CHA and bovine-derived hydroxyapatite had statistically significant. We do the independent samples t-test between low replacement rate of coral hydroxyapatite and high replacement rate of coral hydroxyapatite the phosphorus statistics for independent samples t-test t= 79.748, P=0.000<0.05.At 8 week,the phosphorus content of low replacement rate CHA and high replacement rate of coral hydroxyapatite had statistically significant.By available statistics, At eight weeks the calcium content were significant differences between low replacement rate CHA, high replacement rate CHA and bovine-derived hydroxyapatite. Low replacement rate CHA produced the most calcium, high replacement rate CHA produced the lowest calcium. In the three sample buffer low replacement rate CHA had lowest phosphorus content, and the high replacement rate CHA with bovine-derived hydroxyapatite phosphorus content produced no significant differences.3. About the particle diameter of the sample. The low replacement rate of CHA had a independent samples t-test between 2 weeks and 16 weeks, the result is:2w and 1w are heterogeneity of variance, t=3.889,p=0.01<0.05, described the 16 weeks and the 2 weeks had significant difference.The 16 weeks was significantly less than the 2 weeks sample.About the particle diameter of the sample. The high replacement rate of CHA had a independent samples t-test between 2 weeks and 16 weeks, the result is:2w and 16w are homogeneity of variance, t=-0.761, p=0.453>0.05, described the 16 weeks HCHA and the 2 weeks HCHA had no significant difference in the quality of the sample.The 16 weeks and the 2 weeks sample were not very different.About the particle diameter of the sample. The BDHA in the second week and 16 weeks a sample of material quality independent samples t-test, the result is:16w and 2w heterogeneity of variance, t=-0.035, p=0.972>0.05, described the 16 weeks BDHA and the 2 weeks BDHA had no significant difference in the quality of the sample.The 16 weeks and the 2 weeks sample were not very different.Conclusion1. Different replacement rate of coral hydroxyapatite in vitro by the degradation had different weight loss. And the weight loss differences are significant.2. Different replacement rate of coral hydroxyapatite produced element contents are quite different during degradation.3. The particles varying diameter of different replacement rate of coral hydroxyapatite material were not the same after degradation.