Effects of Indomethacin on the physiologic root resorption of deciduous teeth in dogs / 대한치과교정학회지

This study was aimed to investigate the effects of indomethacin on physiologic root resorption and to examine the dental pulp and tissue changes around the resorbing teeth. 13-14 week old six mongrel dogs were divided into 3 groups; two experimental groups administered indomethacin 2 mg/kg/day and 8 mg/kg/day orally two times a day for 14 days respectively, and control group administered a placebo. The deciduous incisors showing root resorption were selected, fixed for 24 hrs in 10% formalin solution, demineralized in 10% EDTA solution, invested in paraffin and sectioned in 5 micrometer thick sections. The preparations were stained with H and E staining and Masson's trichrome staining and examined under the light microscope. Observation revealed that deciduous root resorbing tissue resembles inflammatory tissue and accompanies bone remodelling. The dental pulp was normal except the area near root resorption, well organized columnar odontoblasts layer under the predentin, and the odontoblasts near root resorption were cuboidal or flat cells in the disrupted layer under the predentin. Indomethacin administered group showed a partial decrease in the number of odontoclasts and nucleus. But there was no sign of pulp change by indomethacin. These results suggest that indomethacin inhibits recruitment of odontoclasts partially and that of osteoclasts more, and so when it is administered for long periods, deciduous root resorption can be delayed and eruption of the successor can be delayed for a short period.

A comparative study on shear bond strengths influenced by time elapsed after bracket bonding with a light-cured glass ionomer cement / 대한치과교정학회지

The purpose of this study was to evaluate effects of time on shear bond strengths of a light-cured glass ionomer cement and chemically cured resin cement to enamel, and to observe the failure patterns of bracket bondings. Shear bond strength of a light-cured glass ionomer cement were compared with that of a resin cement Metal brackets were bonded on the extracted human bicuspids. Specimens were subjected to a shear load(in an Instron machine) after storage at room temperature for 5 and 15 minutes, after storage in distilled water at 37degrees C for 1 and 35 days. The deboned specimens were measured m respect of adhesive remnant index. The data were evaluated and tested by ANOVA, Duncan's multiple range test, and t-test, and those results were as follows. 1. The shear bond strength of light-cured glass ionomer cement is higher than that of resin cement at 5 and 15 minutes. 2. The shear bond strengths of both light-cured glass ionomer cement and resin cement increase with time. There was no significant difference in those of both 1 day group and 35 day group. 3. LIght-cured glass ionomer cement is suitable as orthodontic bracket adhesives.

The effects of surface treatments on shear bond strengths of light-cured and chemically cured glass ionomer cements to enamel / 대한치과교정학회지

The purpose of this study was to evaluate the effects of surface conditioning with 10% polyacrylic acid, etching with 38% phosphoric acid, and polishing with a slurry of pumice on shear bond strengths of light-cured glass ionomer cement, chemically cured glass ionomer cement, and a composite resin to enamel, and to observe the failure patterns of bracket bondings. Shear bond strengths of glass ionomer cements were compared with that of a composite resin. Metal brackets were bonded on the extracted human bicuspids after enamel surface treatments, and samples were immersed in the 37degrees C distilled water bath, and shear bond strengths of glass ionomer cements and a composite resin were measured on the Instron machine after 24hrs passed, and the deboned samples were measured in respect of adhesive remnant index. Scanning electron micrographs were taken of enamel surfaces after various treatments. The data were evaluated and tested by ANOVA and Duncan's multiple range test, and those results were as follows. 1. Shear bond strength of light-cured glass ionomer cement showed statistically higher than that of chemically cured glass ionomer cement. 2. Shear bond strengths of light-cured and chemically cured glass ionomer cements to enamel treated with 10% polyacrylic acid and 38% phosphoric acid showed statistically higher than those with a slurry of pumice. 3. According to scanning electron micrographs, enamel surface conditioned with 10% polyacrylic acid is slightly etched and cleaned, that etched with 38% phosphoric acid is severely etched, and that polished with a slurry of pumice is irregulary scretched and not completely cleaned. 4. After debonding, light-cured glass ionomer cement to enamel treated with 10% polyacrylic acid showed less residual materials on the enamel surface than composite resin to enamel etched with 38% phosphoric acid. 5. There was no significant difference in the shear bond strength of light-cured glass ionomer cement to enamel treated with 10% polyacrylic acid and that of composite resin to enamel etched with 38% phosphoric acid.