• International Journal of Oral Biology
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• 제45권1호
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• pp.25-31
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• 2020

Enamel knot (EK)-a signaling center-refers to a transient morphological structure comprising epithelial tissue. EK is believed to regulate tooth development in early organogenesis without its own cellular alterations, including proliferation and differentiation. EKs show a very simple but conserved structure and share functions with teeth of recently evolved vertebrates, suggesting conserved signaling in certain organs, such as functional teeth, through the course of evolution. In this study, we examined the expression patterns of key EK-specific genes including Dusp26, Fat4, Meis2, Sln, and Zpld1 during mice embryogenesis. Expression patterns of these genes may reveal putative differentiation mechanisms underlying tooth morphogenesis.

• KSBB Journal
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• 제29권2호
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• pp.112-117
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• 2014

The purpose of this study was to evaluate the influence of energy drinks on the erosion of dental enamel and mouse teeth growth. Exposure of enamel surface to energy drinks stimulated the release of the calcium from enamel surface of teeth. And the surface microhardness of enamel decreased after immersion in energy drinks. Enamel demineralization effects under energy drinks were observed by scanning electron microscope. Effect of maternal energy drink intake on tooth morphology of offsprings was analyzed. We concluded that the energy drinks produced a significant erosion of dental enamel.

• 대한치과의사협회지
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• 제48권4호
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• pp.297-307
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• 2010

Noncarious cervical lesions(NCCLs) are characterized as structural defects found on the tooth surface of the cement-enamel junction. Loss of tooth structure through noncarious mechanisms may vary in etiology and clinical presentation for each individual but presently many clinician now classify this as tooth failure of abfraction due to the stress applied in the cervical area of the tooth under oral physiological and pathological loads. In the current study, we investigated the stress distribution of maxillary premolar with NCCL using simulated 3D finite element analysis. The results were as follows: 1. In the sound maxillary premolar, the stresses were highly concentrated at cervical enamel surface of the mesiobuccal line angle, asymmetrically. 2. Once the lesion has been formed, the highest stress concentration was observed around the apex of the wedge shaped lesion. 3. In four types of NCCL, the patterns of stress distribution were similar and the peak stress was observed at mesial corner and also stresses concentrated at lesion apex. 4. Lesion cavity modification of rounding apex, reduced stress of lesion apex. 5. When restoring the notch-shaped lesion, material with high elastic modulus worked well at the lesion apex and material with low elastic modulus worked well at the cervical cavosurface margin.

• Restorative Dentistry and Endodontics
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• 제29권3호
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• pp.219-225
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• 2004

This study evaluated the microshear bond strength of composte resin to teeth bleached with commercial whitening strips and compared with those bleached with home bleaching gel. Twelve extracted human central incisors were cut into pieces and central four segments were chosen from each tooth and embedded in acrylic resin. Four blocks with 12 tooth segments embedded in acrylic resin were acquired and numbered from group one to group four. Group 1 was bleached with Crest Whitestrips, group 2 with Claren, group 3 with Opalescence tooth whitening gel (10％ carbamide peroxide). Group 4 was used as control. The bleaching procedure was conducted for 14 days according to the manufacturer's instructions ; the bleaching strips twice a day for 30 min and the bleaching gel once a day for 2hr. After bleaching, composite resin (Filtek Supreme) was bonded to the enamel surfaces with a self-etching adhesive (Adper Prompt L-Pop) using Tygon tube. Microshear bond strength was tested with a universal testing machine (EZ-test). The data were statistically analysed by one-way ANOVA. The study resulted in no statistical differences in microshear bond strength between the tooth segments bleached with 2 different whitening strips and bleaching gel. It can be concluded that the effect of bleaching with either commercial whitening strips or bleaching gel on enamel is minimal in bonding with self-etching adhesive to composite resin.

• 한국융합학회논문지
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• 제12권12호
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• pp.153-159
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• 2021

본 연구의 목적은 시판되고 있는 청포도 주스와 석류 주스의 노출 시간에 따른 치아 표면 변화에 대한 위험성을 융복합적으로 확인하고자 한다. 발치된 건전 치아를 사용하였으며, 접촉시간에 따른 구분으로 총 8그룹으로 대조군과 10 ml의 시판되는 청포도 주스와 석류 주스를 1, 3, 5, 15, 30, 60, 120분 적용한 실험군 7그룹으로 나누었다. 실험 주스의 pH가 측정되었고 표면의 변화와 미세 형태는 주사전자현미경(Scanning Electron Microscope:SEM)을 통하여 확인하였다. 본 실험에 사용된 청포도 주스는 3.9±0.02, 석류 주스는 3.5±0.01로 제조사가 명시한 주스의 pH 범위보다 청포도 주스는 약간 높았지만 석류 주스는 낮았다. SEM을 통한 결과에서도 대조군과 비교하여 치아 표면의 손상이 생겼다. 접촉 시간이 증가될수록 표면의 손상은 증가되었다. 연구의 결과를 바탕으로 음용 횟수나 구강 내 저류 시간을 줄이고, 치과 임상에서 치아 침식증 환자에게 질환의 진행을 낮출 수 있는 과일 주스에 대한 정확한 정보를 제공해야 할 것이다.

• 치위생과학회지
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• 제19권3호
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• pp.154-161
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• 2019

Background: The market for vitamin drinks is expanding both in Korea and worldwide. However, it was difficult to find studies regarding the possibility of tooth erosion induction due to vitamin drinks. The purpose of the present in vitro study was to evaluate the effect of tooth erosion caused by a few commercial vitamin beverages on bovine teeth enamel in terms of erosion depth and fluorescence loss. Methods: Three experimental groups (vitamin drinks), a positive control group (Coca-Cola), and a negative control group (mineral water) were established. Each group consisted of 5 specimens obtained from sound bovine teeth. The pH and titratable acidity of beverages were measured. Specimens were immersed in the beverages and artificial saliva for 6 and 18 hours, respectively. This cycle was repeated for 5 days. The depth of the tooth loss caused by tooth erosion (erosion depth) and maximum loss of fluorescence (Max ${\Delta}F$) were measured using the microscope and quantified light-induced fluorescence-digital, respectively. For the statistical analysis, the Kruskal-Wallis test and ANOVA were used to compare the erosion depth and Max ${\Delta}F$ of the enamel surfaces. In addition, Spearman correlations were estimated. Results: The pH of the three vitamin beverages ranged from 2.65 to 3.01, which is similar to that of the positive control group. All beverages, except mineral water, had sugar and acidic ingredients. Vitamin drinks and the positive control, Coca-Cola, caused tooth erosion lesions, and showed significant differences in erosion depth compared to mineral water (p<0.05). The vitamin beverages with low pH were associated with high erosion depth and Max ${\Delta}F$. Conclusion: Vitamin drinks have the potential to cause tooth erosion.

• 대한소아치과학회지
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• 제30권2호
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• pp.320-325
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• 2003

이산화탄소 레이저의 출력과 조사시간에 따른 유치 법랑질의 탈회억제 및 재경화 효과를 알아보고자 하였다. 유치 법랑질의 직경 2mm 부위를, 파장 $10.6{\mu}m$ 탈촛점 펄스파 이산화탄소 레이저로 6W 2초 및 3W 8초 조사하고, Diagnodent로 측정하여 탈회억제 및 재경화 효과를 평가하고, 선행 연구의 3W 4초 및 6W 4초 조사 결과와 함께 4개군을 비교하였다. 유치 법랑질을 6W 2초 또는 3W 8초 조사 후 탈회시켰을 때, 조사 전과 조사 후에 비해 탈회 후 측정치가 유의하게 증가하였으며(P<0.05), 군 간에 유의한 차이가 없었다. 4개 군 중 6W 4초 군에서 뚜렷한 탈회억제효과가 있었다. 탈회된 유치 법랑질을 6W 2초 또는 3W 8초 조사하였을 때, 탈회 후에 비해 조사 후 측정치가 유의하게 감소하였으나 탈회 전보다는 유의하게 증가하였고(P<0.05), 군 간에 유의한 차이가 없었다. 4개 군 중 6W 4초 군이 거의 완전한 재경화효과가 있었고, 세 군은 부분적 재경화효과가 있었으며 서로 유의한 차이가 없었다. 치아변색은 6W 4초 조사한 경우에만 나타났다. 우식 억제와 치아변색은 총 조사 에너지보다 출력에 더 의존한다고 사료되었다.

• The Journal of Advanced Prosthodontics
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• 제6권5호
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• pp.423-426
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• 2014

This clinical report presents the clinical appearance and treatment approach in a case of excessive anterior teeth erosion resulted from swimming in a poorly-chlorinated swimming pool. Clinical findings revealed tooth sensitivity, severe enamel erosion resembling veneer preparations, and the presence of anterior open bite. A novel hybrid ceramic (Vita Enamic) was chosen for fabricating full-coverage crowns for this patient. After 6-months follow-up, the tooth sensitivity disappeared and the patient was satisfied with esthetic outcome. The hybrid ceramic restorations can be recommended with no complications.

• 대한소아치과학회지
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• 제33권2호
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• pp.201-206
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• 2006

건전한 치질에 탄산가스 레이저의 조사로 내산성을 증가시키거나 탄산가스 레이저의 조사 전 후에 국소적 불소도포를 함께 시행함으로써 치아우식증 예방효과를 얻을 수 있다. 따라서 이 논문에서는 치아의 법랑질 평활면에 레이저를 조사한 후 법랑질 표면의 변화를 주사 전자 현미경과 원자 현미경을 통하여 관찰하고 불소도포와 레이저 조사를 병용하였을 경우의 차이 및 원자 현미경의 효율성을 알아보고자 한다. 그 결과 대조군과 비교 시 레이저를 조사한 군들에서 미세한 균열과 소와 및 입자형 성상이 관찰되었으며, 불소도포 시에는 좀더 평활한 표면을 보였다. 이러한 레이저와 불소의 병용은 치아 표면에 칼슘, 인 불소가 재흡착되어 표면에 입자형태를 보이며 이것이 치아우식증에 대한 저항성을 나타내는 원인 중 하나라고 생각된다.

• Restorative Dentistry and Endodontics
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• 제28권5호
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• pp.363-368
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• 2003

The purpose of this study is to evaluate the effect of additional enamel etching with phosphoric acid on the microleakage of the adhesion of self-etching primer system. Class V cavity($4mm{\times}3mm{\times}1.5mm$) preparations with all margins in enamel were prepared on buccal surface of 42 extracted human upper central incisor teeth. Prepared teeth were randomly divided into 3 groups. Group 1：no additional pretreatment with 37% phosphoric acid (NE). Group 2：additional pretreatment with 37% phosphoric acid for 10 seconds (E10s). Group 3：additional pretreatment with 37% phosphoric acid for 20 seconds (E20s). The adhesives(Clearfil SE $Bond^{\circledR}$, Kuraray, Osaka, Japan) and composite resins(Clearfil $AP-X^{\circledR}$, Osaka, Kuraray, Japan) were applied following the manufacturer's instructions. All the specimens were finished with the polishing disc(3M dental product, St Paul, MN, USA), thermocycled for 500 cycles between $5^{\circ}C$ and $55^{\circ}C$ and resected apical 3-mm root. 0.028 stainless steel wire was inserted apically into the pulp chamber of each tooth and sealed into position with sticky wax. Surrounding tooth surface was covered with a nail varnish 2 times except areas 1mm far from all the margins. After drying for one day, soaked the samples in the distilled water. Microleakage was assessed by electrochemical method(System 6514, $Electrometer^{\circledR}$), Keithley, USA) in the distilled water. In this study, the microleakage was the lowest in group 1 (NE) and the highest in group 3(E20s)(NE