• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.57-64
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• 2008

It is well established that fluoride products play an important role in the prevention and remineralization of carious lesion. Fluoride varnish is a concentrated topical fluoride and varnishes adhere to tooth surface, permitting prolonged fluoride exposure and uptake. In this study, the artificial initial enamel caries was caused on the sound human enamel and divided 60 specimens into three groups. Group 1 and group 2 were treated with the topical application of fluoride varnish and stored in artificial saliva for 1 and 2 weeks. Group 3 was stored in artificial saliva for 2 weeks, which acted as control group. Changes in mineral contents were analysed with the confocal laser scanning microscope. The following results were obtained: 1. In group 1 and group 2, the total fluorescence of the lesion(TFL) was reduced in remineralized area compared to in demineralized area(p<0.05). 2. The total fluorescence of the lesion of remineralized area was more reduced in group 2 than in group 1(p<0.05). 3. The total fluorescence of the lesion was more reduced in group 2 than in control group(p<0.05). 4. Confocal laser scanning microscope can be used in quantitative analysis of remineralization by fluoride varnish.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.3
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• pp.348-357
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• 2009

The purpose of this study was to evaluate the micro-tensile bond strength (${\mu}TBS$) of four luting resin to regional dentin of human primary teeth. Dentin from non-carious primary molars were prepared from different regions (s, superficial dentin; d, deep dentin; c, cervical dentin), and divided into groups based on anatomical locations and types of luting resins (Scotchbond Multi-purpose : SB ; One-Step : OS ; AdheSE Bond : ASE ; G-Bond : GB) : SB-s, SB-d, SB-c; OS-s, OS-d, OS-c; ASE-s, ASE-d, ASE-c ; GB-s, GB-d, GB-c. Luting resins were used according to the manufacturers' instructions, to bond $Light-Core^{TM}$ Core Build-Up Composite) to the exposed dentin specimens in the light-curing mode. After storage for 1 day, ${\mu}TBS$ was tested at a cross-head speed of 1 mm/min. Data were analyzed with T-test and two-way ANOVA. The bonding interface and fractography analyses were performed with SEM. The results were as follows : 1. ${\mu}TBS$ to superficial dentin was significantly higher than to deep dentin for SB(p<0.05). But there were no significant differences in regional ${\mu}TBS$ among OS, ASE, GB(p>0.05). 2. There were no significant differences in ${\mu}TBS$ to superficial dentin among each groups. But, in deep dentin, ${\mu}TBS$ of SB-d was significantly lower than those of OS-d, ASE-d, and GB-d(p<0.05). ${\mu}TBS$ of OS-d was significantly higher than those of GB-d(p<0.05), but there were no significant differences in ${\mu}TBS$ of ASEd. There were no significant differences among ${\mu}TBS$ of ASE-d, OS-d, and GB-d.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.285-294
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• 1991

The human temporomandibular joint as a ginglymoarthrodial one has much in common with the other synovial joints of the body, but it does possess an unique charachteristic in that it must accomodate the various occlusal relations of dentition during an end point of closure. For that reason, the movement of the condyle in the temporomandibular joint is susceptible to influences from the nature of occlusion. Undue loading to the temporomandibular joint can be applied on the occasion of premature contacts in centric relation, balancing side interferences, change of occlusal surfaces due to excessive attrition, loss of tooth. Such occlusal disharmonies in association with the systemic and emotional factors may give rise to the temporomandibular disorder. On the other hand, the changes of occlusal patterns in the growing body can also have an effect on the growth of the temporomandibular joint through the alterations of functional stresses. The purpose of this study was to observe histopathologic response of the temporomandibular joint in unilateral chewing on one side exclusively for 10 months. Three dogs showing normal masticatory function were chosen. One dog aged about 12 months was for control, two dogs for experimental specimens were about 12 and 18 months old respectively. For chewing on the left side only, unilateral lower right premolar and molar were extracted in two experimental specimens. And then three dogs were sacrificed 10 months later. Frontal histologic sectioning of joints were done for the observation of the effects of one-side chewing. 24 specimens from three dogs were obtained and fixed in 10% formalin and routinly processed with H-E staining for histologic examination. The light microscopic findings were interpretated as follows: 1. Experimental specimen 1 aged about 22 months: In comparison with control and right non-chewing side, the proliferative and hypertrophic zone were increased at the mesial and lateral part of left chewing side condyle. There was no change of the articular tissue of temporal bone. 2. Experimental specimen 2 aged about 28 months: The articular tissues of adult joint were observed. The differences between the chewing and non-chewing side were not seen in the articular tissues of condyle and temporal bone.

• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.947-954
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• 1998

The purpose of this study was to compare shear bonding strengths and debonding patterns of the ceramic brackets attached on the crystal which were grown on the enamel surface of a tooth with different concentrations of lithium sulphate-contained polyacrylic acid in different application times. Four kinds of concentrations of mixed solutions were made and applied to the enamel surface on extracted human premolars. The solutions were made by adding 0.3M or 0.6M of lithium sulfate to $50\%\;or\;65\%$ of polyacrylic acid with 0.3M sulfuric acid. The solutions were applied for 30 or 60 seconds. After bonding, a universal testing machine was used to measure the shear bond strength, and then observations were made of debonding patterns through the stereoscope. And the enamel surface was observed through the scanning electron microscope to examine the pattern of crystal growth and debonding. The results were as follows: 1. Shear bond strength in the enamel surface treated with $50\%$ polyacrylic acid was higher than that with $65\%$ polyacrylic acid. 2. There were no statistical differences in shear bond strength according to concentration of lithium sulfate and application time of solutions . 3. Enamel surface was almost free of resin debris after debonding. 4. Enamel surface treated with $50\%$ polyacrylic acid showed higher density of crystal growth than that with $65\%$ polyacrylic acid under scanning electron microscope.

• The korean journal of orthodontics
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• v.39 no.6
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• pp.393-401
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• 2009

Objective: The purpose of this study was to compare the shear bond strength (SBS) of brackets and microleakage of a tooth-adhesive-bracket complex bonded with a direct and an indirect bonding technique after thermocycling. Methods: Fifty non-carious human premolars were divided into two equal groups. In the direct bonding group a light-cured adhesive and a primer (Transbond XT) was used. In the indirect-bonding group, a light-cured adhesive (Transbond XT) and chemical-cured primer (Sondhi Rapid Set) were used. After polymerization, the teeth were kept in distilled water for 24 hours and thereafter subjected to thermal cycling (500 cycles). For the microleakage evaluation, 10 teeth from each group were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, and examined under a stereomicroscope. Fifteen teeth from each group were used for SBS testing with the universal testing machine and adhesive remnant index (ARI) evaluation. Data were analyzed using the Mann-Whitney U test, Chi-square test, and Fisher's exact test. Results: There were no statistical differences on SBS and microleakage between the two bonding techniques. The indirect bonding group had a significantly lower ARI score. Bracket failures were obtained between enamel-resin interfaces. Conclusions: The type of bonding technique did not significantly affect the amount of microleakage and SBS.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.577-577
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• 2001

The lastest concepts in bonding are "total etch", in which both enamel and dentin are etched with an acid to remove the smear layers, and "wet dentin" in which the dentin is not blown dry but left moist before application of the bonding primer. Ideally, the application of a bonding agent to tooth structure should be insensitive to minor contamination from oral fluids. Clinically contaminations such as saliva, gingival fluid, blood and handpiece lubricant are often encountered by dentists during preparation of a restoration. The aim of this study was to evaluate the effect of contamination by hem-ostatic agents on shear bond strength of compomer restorations. One hundred and ten extracted human maxillary and mandibular molar teeth were collected. The teeth were cleaned from soft tissue remnant and debris and stored in physiologic solution until they were used. Small flat area on dentin of the buccal surface were wet ground serially with 400, 800 and 1200 abrasive paper on automatic polishing machine. The teeth were randomly divided into 11 groups. Each group was conditioned as follows: Group 1 : Dentin surface was not etched and not contaminated by hemostatic agents. Group2 : Dentin surface was not etched but was contaminated by Astringedent (Ultradent product Inc., Utah, U.S.A.). Group3 : Dentin surface was not etched but was contaminated by Bosmin (Jeil Phann, Korea.). Group4 : Dentin surface was not etched but was contaminated by Epri-dent (Epr Industries, NJ, U.S.A.). Group5: Dentin surface was etched and not contaminated by hemostatic agents. Group 6 : Dentin surface was etched and contaminated by Astringedent. Group7 : Dentin surface was etched and contaminated by Bosmin. Group8 : Dentin surface was etched and contaminated by Epri-dent. Group9 : Dentin surface was contaminated by Astringedent. The contaminated surface was rinsed by water and dried by compressed air. Group10 : Dentin surface was contaminated by Bosmin. The contaminated surface was rinsed by water aud dried by compresfed air. Group 11 : Dentin surface was contaminated by Epri-dent. The contaminated surface was rinsed by water and dried by compresfed air. After surface conditioning, F2000 was applicated on the conditoned dentin surface. The teeth were thermocycled in distilled water at $5^{\circ}C\;and\;55^{\circ}C$ for 1000 cycles. The samples were placed on the binder with the bonded compomer-dentin interface parallel to the lmife-edge shearing rod of the Universal testing machine(Zwick 020, Germany) running at a cross head speed of 1.0mmimin. There were no significant differences in shear bond strength between groups 1 and group 3 and 4, but group 2 showed significant decrease in shear bond strength compared with group 1. There were no significant differences in shear bond strength between group 5 and group 7 and 8, but group 6 showed significant decrease in shear bond strength compared with group 5. There were no significant differences in shear bond strength between group 5 and group 9, 10 and 11.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.359-374
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• 2000

Cyclosporine A(CsA) is a widely used immunosuppressant for transplant patients and is also used for the treatment of a wide variety of systemic diseases with immunologic disorders. However, its use is frequently limited because of complications such as nephrotoxicity or gingival hyperplasia. Although several hypotheses have been postulated for CsA-induced gingival hyperplasia, i.e. various cytokine effects of inflammatory cells, existence of plaque or CsA itself, but its pathogenesis is still unclear. For experimental chronic CsA toxicity, salt depletion has been shown to increased susceptibility of rodents to the effects of CsA, and this maneuver facilitates production of arteriolopathy and interstitial fibrosis in kidney that mimic the changes found in human. The purpose of this study was to evaluate pathogenesis of CsA-induced gingival hyperplasia by comparing changes between CsA administration groups of normal standard diet and those of low salt diet group. Specific pathogen-free, 20 to 25 days old(120 to 150 g), male Fisher-344 rats(KIST, Korea), 120 to 150g of body weight, were assigned to four groups of six animals each after one week of adaptation period for powder food. Group 1 received olive oil($300{\mu}l/g\;of\;diet$) with normal standard diet(0.4% of sodium)(NSD). Group 2 received CsA(Cypol-N, Jonggundang, Korea; $300{\mu}g/g\;of\;diet$) with normal standard diet(NSD+CsA). Group 3 received same amount of olive oil with low salt diet(0.05 % of sodium, Teklad Premier, U.S.A.)(LSD). Group 4 received same dose of CsA with low salt diet(LSD+CsA). Rats were pair fed and were sacrificed after six weeks. Renal histologic lesions associated with CsA, consisted of cortical interstitial fibrosis, tubular atrophy and hyalinization of arterioles and the impairment of renal function including increase of serum creatinine and decrease of glomerular filtration rate was more severe in low salt diet group. These were proved as the results of activated of renin-angiotensin system in the kidney by low salt condition. Meanwhile the degree of gingival hyperplasia at incisor and molar tooth was less severe in low salt diet group compared with normal sodium diet group. Hyperplastic gingiva showed mild epithelial hyperplasia and expanded underlyng stroma which consisted of matrix increasement, capillary proliferation and dilatation. While the number and the activation of fibroblasts were increased, inflammatory cells were rare in the stroma. The immunohistochemistry for TGF-${\beta}_1$ in the kidney and gingiva revealed stronger positive in LSD+CsA in kidney but in gingiva of NSD+CsA. These results suggested followings; Gingival hyperplasia can be developed without inflammatory cells infiltration and seemed not induced by CsA by itself. The major role for gingival hyperplasia by CsA would be the secondary effect of TGF-${\beta}$, which maybe upregulated by CsA administration. Low salt diet can attenuate this hyperplasia perhaps by decreasing the activation of $TGF-{\beta}$.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.23-33
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• 2003

The purpose of this study was to compare in vitro interfacial relationship of restorations bonded with three self-etching primer adhesives and one self-etching adhesive. Class I cavity preparations were prepared on twenty extracted human molars. Prepared teeth were divided into four groups and restored with four adhesives and composites Clearfil SE $Bond/Clearfil^{TM}$ AP-X (SE), UniFil $Bond/UniFil^{\circledR}$ F (UF), FL $Bond/Filtek^{TM}$ Z 250 (FL) and Prompt $L-Pop/Filtek^{TM}$ Z 250 (LP) After storing in distilled water of room temperature for 24 hours, the specimens were vertically sectioned and decalcified. Morphological patterns between the enamel/dentin and adhesives were observed under SEM. The results of this study were as follows : 1. They showed close adaptation between enamel and SE, UF and FL except for LP. 2. The hybrid layer in dentin was $2{\;}\mu\textrm{m}$ thick in SE, $1.5{\;}\mu\textrm{m}$ thick in UF, and $0.4{\;}\mu\textrm{m}$ in both FL and LP. So, the hybrid layers of SE and UF were slightly thicker than that of FL and LP. 3. The lengths and diameters of resin tags in UF and FL were similar, but those of LP were slightly shorter and slenderer than those of SE. 4. The resin tags were long rod shape in SE, and funnel shape in other groups Within the limitations of this study, it was concluded that self-etching primer adhesives showed close adaptation on enamel. In addition, the thickness of hybrid layer ranged from $0.4-1.5{\;}\mu\textrm{m}$ between adhesives and dentin. The resin tags were long rod or funnel shape, and dimension of them was similar or different among adhesives.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.595-607
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• 1999

The purpose of this in vitro study was to evaluate the efficacy of self-etching primer which was developed to simplify the bonding procedures by measuring the shear bond strength and observing the interfacial morphology. 90 flat dentinal surfaces were prepared by grinding the buccal and lingual areas of caries-free human deciduous molars. After bonding of composite resin to sample surfaces according to the manufacturer's direction and thermocycling, shear bond strengths were measured using Universal testing machine(Instron). Another groups of specimens were treated by hydrochloric acid to secure the resin only and those tags were evaluated under SEM for their length and forms and the morphology of the bonding sites were also observed. The result as follows. 1. Group III showed higher shear bond strength than group I and II but no statistically significant difference was founded between group I and II(p>.05). 2. Adhesive failure was predominant in group II whereas dentin detachment was the main failure pattern in group I and III. 3. Relating long resin tags of $100-200{\mu}m$ were observed in samples of all groups under SEM. In group I, homogeneously long resin tags were arranged rather tight whereas rather loosely arranged resin tags of various length were found in group II. Lateral branching of resin tags was the characteristic finding observed in group III.

• Journal of dental hygiene science
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• v.8 no.4
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• pp.367-373
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• 2008

The natural products are used to be development of new antibacterial substances against human pathogenic bacteria. Adherence to the tooth surface by S. mutans is an important step in initiation of dental caries. This study was to examine antibacterial activity and anti-adhesive effect of Scutellaria baicalensis extract against S. mutans. Extracts of S. baicalensis were tested for antimicrobial activities by paper disc methods and radial diffusion assay methods, and bacterial adherence assay using 3 type of hydroxyapatite. The antibacterial level of ethyl acetate extract, IPK-3 on the growth of S. mutans was 125 mg/ml of minimum inhibitory concentration (MIC). The maximum growth of S. mutans in medium added with IPK-3 extract (50 mg/ml) was delayed to 30 hr, while the highest at 24 hr in control medium. The pH values of the control medium was 5.63 at 18 hr, but the media supplemented with IPK-3 extract was pH 6.50 at 12 hr. In adhesive inhibition assay, S. mutans was labelled with the fluorescent indicator DAPI and measured with fluorescence microscope. Adhesion of S. mutans on hydroxyapatite beads was inhibited by IPK-3 extracts. These results suggest that S. baicalensis extract can be used as an effective material for antibacterial activity and adhesive inhibition against S. mutans.