| Summary: | 碩士 === 國立臺灣大學 === 臨床牙醫學研究所 === 98 === The statins are commonly prescribed drugs that inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG Co-A) reductase and decrease hepatic cholesterol biosynthesis, thereby reducing serum cholesterol concentrations and lowering the risk of heart attack. Recently, lots of studies found that statins showed enhanced expression of BMP-2 mRNA, which can induce the regeneration of bone and dental pulp tissue.
However, the efficacy of statin using oral administration is not expected, because the ultimate systemic availability is only 2.4%, far less than bone formation needed. When injected locally, statin has the side effect of cytotoxicity. Therefore, a suitable control release device is important to deliver the drug.
In this study, 20 male wistar rats were used. The animals were randomly divided into 4 groups. Artificial bony defects of 5mm were created with bone trephine bur on mandibular bodies of both sides. Group 1 received 1 mg PLGA nanoparticles containing lovastatin in the right side defects and gelfoam was placed in the left side defects which served as control. Group 2 received 3 mg PLGA nanoparticles containing lovastatin in the right side defects and gelfoam was placed in the left side defects. Group 3 received 1 mg PLGA nanoparticles containing lovastatin in the right side defects and 1 mg PLGA nanoparticles without lovastatin were placed in the left side defects. Group 4 received 3 mg PLGA nanoparticles containing lovastatin in the right side defects and 3 mg PLGA nanoparticles without lovastatin were placed in the left side defects. CBCT scan was used at 3, 6, 9, and 12 weeks after surgery to measure the progressive volume changes of the artificial bony defect. The rats were sacrificed at 12 weeks, and the mandible bones were sent for histological examination.
According to the X-ray scan, each group shows the trend of bone healing through time, but group I has the most significant outcome. We can also find new bone formation under histological examination. Thus, using proper delivery device, lovastatin has the ability to induce bone healing and regeneration.
In the odontogenic induction study, we used 4 miniature pigs, with a total number of 24 deciduous anterior teeth. All teeth were randomly divided into 4 groups. Class V cavities were created on each tooth, then the cavities were deepened to expose the pulp tissue. After bleeding control and irrigation. Group I were restored with GIC directly. Group II capped with MTA, then restored with GIC. Group III capped with lovastatin, then restored with GIC. Group IV capped with red fluorescent SHED, then restored with GIC. After a healing period of 45 days. All the teeth were extracted. After periapical film and CBCT scan, histological examination were used to examine the reparative dentin formation.
Under CT scan, group I, II and III could find calcified images in pulp space. Under microscope, reparative dentin could be found in group I, II and III, and the underlying pulp tissue were all vital. Thus, lovastatin may have the ability to protect exposed pulp tissue and induce reparative dentin formation.
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