• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.51-64
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• 1986

The purpose of this study is to obtain the data of prestep in cavity preparation by observing changed conditions of laser irradiated dental hard tissues. The forty five extracted caries free human molars were divided into three groups and each group into five subgroups. A $CO_2$ laser irradiation was performed each subgroup of group I for one second with output power of 5 W, 10 Wand 20 W. On group II, laser irradiation was done ten times for 0.1 second duration using same power ratings as group I. On group III, laser irradiation was done 0.1 second, 0.2 second and 0.4 second with output power of 50 W. We investigated mineral contents and crater wall of obtained specimens, i.e., laser irradiated teeth, using computer controlled electron probe microanalyzer and scanning electron microscope. The following results were obtained: 1. Both calcium and phosphorus contents in laser irradiated enamel crater wall were increased, and magnesium content was decreased, but these trends were not statistically significant. 2. In laser irradiated dentin, change of mineral content was more significant. 3. In laser irradiated enamel and dentin, there were no significant differences on mineral content change due to irradiation condition and energy density. 4. In scanning electron microscopic study, enamel rods of the crater wall were fused and clefts were observed in parallel with the direction of enamel rod for all groups. 5. In laser irradiated dentin, irregular fusion and clefts were observed. In irradiated teeth with high power and short duration, the locally formed narrow crater wall was observed.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.141-152
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• 1990

The purpose of this study was to evaluate the effects of dentin adhesives(Gluma$^{(R)}$ and Scotchbond 2$^{(R)}$) on the marginal adaptation of light cured composite resin (Heliosit$^{(R)}$) by using SEM. The recently extracted 30 teeth were used and round cavities were prepared on the occlusal surfaces of the teeth with predesigned depth and diameter. The teeth were divided into three groups. Group 1 : Gluma$^{(R)}$ + Heliosit$^{(R)}$ Group 2 : Scotchbond 2$^{(R)}$ + Heliosit$^{(R)}$ Group 3 : Enamelbond$^{(R)}$ + Heliosit$^{(R)}$ Filling with Heliosit, the teeth were stored in saline solution for 24 hours. After the thermocycling procedure, the teeth were cut vertically into the restorations. The SEM observation was carried out to evaluate the marginal adaptation of the composite resin. The following results were obtained. The following results were obtained. 1. The groups using Gluma$^{(R)}$ and Scotchbond 2$^{(R)}$ showed better than the control group on marginal adaptation to the dentin. 2. The group using Gluma$^{(R)}$ was superior to the group using Scotchbond 2$^{(R)}$, but the difference was not significant. 3. In all groups, the marginal gaps were wider on the pulpal walls than on the lateral walls of restorations.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.44-56
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• 1990

This study was designed to assess the degree of the marginal leakage of posterior composite restorations with glass ionomer cement base and Scotchbond$^{(R)}$ by means of the dye penetration at the enamel and dentinal margins. 160 cavities of class V were prepared on the buccal and lingual surfaces of 80 extracted premolar and molar teeth, which were divided into two groups. The buccal cavities of one group were filled with GC lining cement$^{(R)}$, Scotchbond$^{(R)}$ and P 50$^{(R)}$ and the lingual cavities were filled with Scotchbond$^{(R)}$ and Heliomolar$^{(R)}$. The Buccal cavities of other group were filled with Logobond$^{(R)}$, Scotchbond$^{(R)}$ and Heliomolar$^{(R)}$ and lingual cavities were filled with Scotchbond$^{(R)}$ and P 50$^{(R)}$. After finishing, all specimens were subjected manually to 50 thermal cycles at $4^{\circ}C$ and $60^{\circ}C$. They were immersed in 0.5% methylene blue solution for 24 hours and buccolingually sectioned with diamond disc. The sectioned specimens were examined under light microscope. The following results were obtained. 1. The group filled with glass ionomer cement base showed less marginal leakage than the group filled without glass ionomer cement base. 2. The enamel margins showed less microleakage than the dentinal margins in both of the two groups. 3. No significant difference was showed in the microleakage, irrespective of two glass ionomer cement base and posterior composite resin.

• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.107-116
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• 1986

The primary aim of this study was to assess the effects of the margin designs and composite resins on the marginal leakage of Class V resin restorations. 60 Class V cavities with $90^{\circ}$ butt joint, 60 with $45^{\circ}$ bevel joint, and 60 with concave joint were prepared on the labial surfaces of 38 extracted anterior teeth and the buccal and lingual surfaces of 71 premolars, and classified as the butt group, bevel group and concave group, respectively. After completion of the cavity preparation, Heliosit${(R)}$ was filled in 20 butt joint cavities, 20 bevel joint cavities, and 20 concave cavities. And Hi-Pol$^{(R)}$ and Palfique$^{(R)}$ were filled in the same manner, respectively. After finishing, all specimens were subjected manually to 50 thermal cycles at $4^{\circ}C$, $37^{\circ}C$, and $60^{\circ}C$. They were immersed in 0.5% methylene blue solution for 24 hours, and buccolingually sectioned with sectioning machine. The sectioned specimens were examined under the light microscope. The results indicated the following: 1. The bevel group showed the least amount of marginal leakage compared with the other two design groups, but the statistical analysis showed no significant difference at the 95% confidence level. 2. Hi-Pol$^{(R)}$ group showed the most severe marginal leakage compared with the other composite resin materials, but there was no significant difference in the groups. 3. The bevel-Heliosit$^{(R)}$ subgroup, which was filled with Heliosit$^{(R)}$ in the beveled cavities, showed the least amount of marginal leakage, but there was no significance in all the subgroups.

• Restorative Dentistry and Endodontics
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• v.26 no.4
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• pp.285-295
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• 2001

The objective of this study was to investigate the inhibitory effect of taurine and alendronate on the osteoclast differentiation. Osteoblasts and bone marrow cells from 1-2 day old mouse were co-cultured in 10% fetal bovine serum - minimal essential media (FBS-MEM). Osteoclast differentiation was induced by adding the sonicated extracts of Porphyromonas gingivalis (P.gingivalis). Osteoclasts were identified using tartrate resistant acid phosphotase staining (TRAP). Alendronate of 10$^{-7}$, 10$^{-6}$, 10$^{-5}$M and taurine of 500, 1000, 1500$\mu\textrm{g}$/ml were added respectively. The cytotoxic effects of alendronate and taurine were examined using MTT(3-(4,5-dimethylthiazol -2-yl-2,5-diphenyltetrazo- lium bromide) method. After culturing with the sonicated extracts of P.gingivalis, the amounts of IL-6 in the culture supernatant were measured and compared using the ELISA method. The results were as follows : 1. Osteoclasts were differentiated at the concentration of 0.01~0.1$\mu\textrm{g}$/ml sonicated extracts of P.gingivalis. (P<0.05). 2. Alendronate inhibited osteoclasts differentiation at the concentration of 10$^{-5}$ M when the concentration of sonicated extracts of P.gingivalis was 0.01$\mu\textrm{g}$/ml. 3. Taurine inhibited osteoclasts differentiation at the concentration of 1500$\mu\textrm{g}$/ml when the concentration of sonicated extracts of P.gingivalis 0.01$\mu\textrm{g}$/ml. 4. In cytotoxic test (MTT test), no cytotoxic effect was evident in all concentrations of alendronate and taurine. 5. Taurine (10$^{-5}$M) and alendronate(1500$\mu\textrm{g}$/ml) did not change the amounts of IL-6 induced by sonicated extracts of P.gingivalis significantly.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.338-358
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• 2000

The effect of bench drying or removal of the periodontal ligament with NaOCl upon periodontal healing and root resorption after replantation of molars was studied in rats. A total of 40 Sprague-Dawley female rats were used and fed a powdered purina rat chow diet containing 0.4% beta-aminoproprionitrile. The maxillary first molars were extracted and the periodontal ligaments were removed either by bench drying for 15 minutes or by immersion in 2.5% NaOCl solution. The rats were sacrificed at 5, 10, and 21 days by heart infusion. In order to observe the effect of 0.5% stannous fluoride, $10^{-4}M$, $10^{-2}M$, and 1M etidronate disodium on the early stage of periodontal healing, the periodontal ligament was removed with 2.5% NaOCl followed by immersion of the molar in the respective solutions for 5 minutes. The rats were sacrificed after 10 days and the following results were obtained. 1. The removal of the periodontal ligament with 2.5% NaOCl seemed to be more effective than bench drying, since the resorption area in the NaOCl treated group showed a gradual increase whereas a decline in resorption area from 5 days to 21 days was observed in the bench dried group. 2. The application of 0.5% stannous fluoride seemed to enhance the periodontal ligament attachment and active migration of fibroblasts could be observed. 3. The application of $10^{-4}M$, $10^{-2}M$, and 1M etidronate disodium led to a good periodontal ligament attachment. No evident areas of root resorption were found. 4. The use of ${\beta}$-APN made it possible to extract the maxillary first molar with all five roots intact.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.6
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• pp.43-49
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• 2004

Electric pulp test is a method to examine the vitality of dental pulp using physical and chemical stimulation. During the pulp test, the current stimulates intradental nerve, and it makes patients painful. In this paper, we measured each activating response EMG in anterior belly of digastric muscle, voice, and finger movement during the pulp test by increasing stimulus intensity gradually. We also measured excessive stimulus time from the activating responses (EMG, voice, and finger movement) to the end of the stimulation. We measured and analyzed excessive stimulus time for each stimulus detecting method. As a result, we developed automatic stimulus breaker using the human responses to stimulus during electric pulp test. We reduced the excessive stimulus time by disconnecting the pulp tester stimulus output rapidly in 10 ms after activating human response.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1277-1286
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• 2004

The concern and request of high-quality software has been increased according to the rapid transition of society to information-oriented era. Therefore activities of software quality management are regarded as serious as the activities of software development. Moreover, stakeholder of software may have various views of software quality. And some quality characteristics need to be managed with priorities in Software Development Life Cycle (SDLC). Hence we recognized that weights of quality characteristics might be useful to improve efficiency of quality management activities. However, this topic has not actively issued because its necessity and effectiveness has been ignored. This paper presents a technique to decide weights of software quality characteristics in SDLC. It is based on ISO/IEC 9126 which is the standard for software product quality. It is accomplished by questionnaires intended for stakeholder in software development and weight analysis through AHP (Analytic Hierarchical Process) method. Accordingly, it can select quality characteristics by weight in SDLC. And then it helps us to acquire high duality software through measuring software quality quantitatively and expecting the quality after completion of software development.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.78-84
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• 2000

The aim of this study was to compare shaping ability of nickel-titanium rotary files with different taper in simulated resin canals. The instruments used in this study were GT with .04 taper ProFile with ISO-sized tip, .04 taper ProFile with ISO-sized tip alone, and .02 taper Naviflex file and all canals were prepared by crown-down technique. A total of 30 composite images were made from pre- and post-canal scanned images using Scanjet 4C scanner and Corel photopaint 8.0 and then, prevalence of canal aberrations was measured. The amount of coronal substance the instruments removed was also calculated two-dimensionally on digitized images with the Brain C software to compare the relative enlarging efficiency. Finally, the prepared internal canal form was evaluated three-dimensionally with impression technique. The results were as follows; 1. The incidence of zipping in Naviflex group was significantly high compared to the other two groups(P<.05). 2. The amount of coronal substance the GT combined group removed was significantly larger than the other two groups(P<.05). 3. The GT combined group produced canals with good taper and flow. Under the conditionas of this study, the combined use of larger tapered nickel-titanium rotary files prepared simulated canals safely, efficiently and with good three-dimensional form.

• Restorative Dentistry and Endodontics
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• v.36 no.2
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• pp.149-153
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• 2011

As the dental pulp is encased with a rigid, noncompliant shell, changes in pulpal blood flow or vascular tissue pressure can have serious implication for the health of pulp. Numerous studies have demonstrated that orthodontic force application may influence both blood flow and cellular metabolism, leading degenerative and/or inflammatory responses in the dental pulp. The aim of this case report is to present a case about tooth with chronic periapical abscess which showed normal vital responses. Excessive orthodontic force is thought to be the prime cause of partial pulp necrosis. Owing to remaining vital tissue, wrong dianosis can be made, and tooth falsely diagnosed as vital may be left untreated, causing the necrotic tissue to destroy the supporting tissuses. Clinician should be able to utilize various diagnostic tools for the precise diagnosis, and be aware of the endodontic-orthodontic inter-relationship.