• Journal of Oral Medicine and Pain
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• v.26 no.4
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• pp.395-406
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• 2001

지난 수십년동안, 다양한 레이저기기를 이용하여 치아 경조직에 대한 응용 실험을 수행되었다. 그러나, 발생한 주요한 문제는 열발생과 플라즈마 형성과 같은 부작용이 지속된다는 점이었다. 실망스러운 실험결과에 따라 치아 삭제에 대한 레이저의 응용에 대한 연구가 거의 진행되지 못하였다. 본 연구의 목적은 국내에서 처음으로 개발된 얼비움레이저기기를 사용하여 다양한 에너지 수준과 다양한 펄스빈도에서 법랑질의 삭제율을 비교하고자 하였다. 본 연구에 사용된 레이저기기는 국내에서 최초로 개발된 $2.94{\mu}m$ 펄스를 $250{\mu}s$ 방출하는 얼비움야그레이저 기기이다. 기기의 에너지는 20 mJ에서 350 mJ까지 다양하게 방출하며, 최대 출력은 3.5 W이다. 22개의 치아를 에폭시 레진에 포매하고 경화하였다. 치아의 법랑질을 회전 다이아몬드 칼을 흐르는 물과 함께 사용하여 협측 또는 설측으로 평탄하게 삭제하였다. 제작된 법랑질표면은 6개의 구획으로 구분하여 에너지 수준과 펄스빈도에 따라 조사하였다. 본 연구에서 사용된 표본 수는 132개이며, 삭제율을 조사하기 위한 모든 표본은 22개의 실험 군으로 분류하였다. 실험결과는 다음과 같다. 1. 에너지 수준간에는 유의한 삭제율의 차이가 있었다. 2. 40 및 80 mJ로 조사한 경우에는 펄스빈도 간에 차이가 없었지만, 120 mJ의 출력으로 동일한 에너지를 조사한 경우에는 20 Hz가 40 또는 80 mJ로 조사한 경우 보다 가장 삭제효과가 높았다. 3. 연속조사 한 경우 조사시간 경과에 따라 법랑질의 삭제율은 증가되지 않았다. 결론적으로 효과적으로 법랑질을 삭제하기 위해서는 적절한 에너지와 펄스의 레이저를 사용해야 하며, 또한 항상 정확한 초점거리를 유지해야 할 것으로 사료된다.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.2
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• pp.237-244
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• 2021

Dentinogenesis imperfecta (DI) is a hereditary disorder of dentinal defect. It is generally inherited as a single autosomal dominant trait. DI usually affects both the primary and permanent dentition. Affected teeth have various types of discolorations, rapid destruction of the dentin, and severe attrition. In radiologic view, the affected teeth have bulbous crowns, short roots and narrow or closed pulp chambers. The treatment objective is to prevent additional attrition and recover the vertical dimension of occlusion. The aim of this report was to present the long-term prognosis in 15 years in a pair of siblings. Both the patients had DI with tooth attrition and discoloration. Different treatment procedures were used, depending on the difference in the timing of intervention. The first patient saved most of his teeth. The second patient had all of her teeth extracted. This report could be helpful for early diagnosis and overall treatment of DI.

• The Journal of the Korean dental association
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• v.53 no.12
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• pp.935-948
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• 2015

목적: 법랑기질 유도체(EMD)가 사람 치주인대 줄기세포(hPDLSC)의 조직 형성능에 미치는 영향을 in vitro와 in vivo 분석 모델을 이용해 평가한다. 재료 및 방법: hPDLSC를 배양하여 운반체와 함께 면역 억제된 쥐 등에 이식하였다; (1)대조군: EMD 처치하지 않은 운반체에 심어진 hPDLSC군 ($EMD^-/hPDLSC^+$), (2)실험군: EMD 처치한 운반체에 심어진 hPDLSC군 ($EMD^+/hPDLSC^+$). 각 군당 5마리씩 시행하고 8주 후 희생하였다. 조직학적, 조직계측학적 분석을 통해 형성된 백악질의 면적과 백악세포의 수 그리고 샤피 섬유의 수를 계측하였으며 면역조직화학적 분석을 통해 백악질과 교원질 형성을 평가하였다. 또한 in vitro에서 hPDLSC의 수용성 교원질과 glycosaminoglycan 형성에 대한 EMD의 효과를 분석하였다. 결과: 조직학적 분석에서 교원질성 치주 인대 조직이 실험군에서 현저하게 많이 생성된 것을 관찰할 수 있었다. 형성된 백악질의 면적과 백악세포의 수는 군 간 차이가 없었으나, 새롭게 형성된 샤피 섬유의 수는 실험군에서 대조군보다 유의하게 많았다(p<0.05). 교원질 형성에 대한 면역조직 화학적 분석 결과, 실험군에서 I, III형 교원질과 hydroxyproline의 발현이 높았다. 또한 in vitro에서 hPDLSC에 의한 수용성 교원질과 glycosaminoglycan 형성이 EMD의 농도에 비례하여 증가하였다 (p<0.05). 결론: EMD는 hPDLSC에 의한 샤피 섬유 및 교원질 생성을 증가시키고, 이는 새로운 백악질의 기능적 부착과 치주조직 재생에 중요한 역할을 한다.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.327-334
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• 2007

The purpose of this study was to evaluate the effect of burs on microleakage of Class V resin restorations when a self-etching primer adhesive was used. Forty Class V cavities were prepared with four different cutting burs on extracted third molars, and divided into one of four equal groups (n = 10); Group 1-plain cut carbide bur (no. 245), Group 2-cross cut carbide bur (no. 557), Group 3-fine diamond bur (TF-21F), Group 4-standard diamond bur (EX-41). The occlusal and gingival margin of cavities was located in enamel and dentin, respectively. Cavities were treated with Clearfil SE Bond and restored with Clearfil AP-X. Specimens were thermocycled, immersed in a 2% methylene blue solution for 24 hours, and bisected longitudinally. They were observed leakages at enamel and dentinal margins. Data were analyzed using Mann-Whitney and Wilcoxon signed ranked test. The results of this study were as follows; 1. At enamel margin, microleakage of group 4 was statistically higher than those of group 1, 2 and 3 (p < 0.01). 2. At dentinal margin, microleakage of group 4 was statistically higher than group 3 (p < 0.01), but group 1 and 2 were not statistically different with group 3 and 4. 3. Enamel microleakage was statistically higher than dentinal microleakage in group 1, 2 and 3 (p < 0.05), but statistical difference between the microleakage of enamel and dentinal margin was not in Group 4. In conclusion, the use of coarse diamond bur showed high microleakage at both enamel and dentinal margin when Clearfil SE Bond was used in class V cavity.

• Restorative Dentistry and Endodontics
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• v.32 no.6
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• pp.498-513
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• 2007

Since it was reported that incipient enamel caries can be recovered, previous studies have quantitatively evaluated that enamel artificial caries have been, remineralized with fluoride showing simultaneously the increase of width of surface layer and the decrease of width of the body of legion. There is, however, little report which showed that remineralization could occur without fluoride. In addition, the observations on the change of hydroxyapatite crystals also have been scarcely seen. In this study, enamel caries in intact premolars or molars was induced by using lactic acidulated buffering solutions over 2 days. Then decalcified specimens were remineralized by seven groups of solutions using different degree of saturation(0.212, 0.239, 0.301, 0.355) and different pH(5.0, 5.5, 6.0) over 10 days. A qualitative comparison to changes of hydroxyapatite crystals after fracturing teeth was made under SEM(scanning electron microscopy) and AFM(atomic force microscopy). The results were as follows: 1. The size of hydroxyapatite crystals in demineralized area was smaller than the normal ones. While the space among crystals was expanded, it was observed that crystals are arranged irregularly. 2. In remineralized enamel area, the enlarged crystals with various shape were observed when the crystals were fused and new small crystals in intercrystalline spaces were deposited. 3. Group 3 and 4 with higher degree of saturation at same pH showed the formation of large clusters by aggregation of small crystals from the surface layer to the lesion body than group 1 and 2 with relatively low degree of saturation at same pH did. Especially group 4 showed complete remineralization to the body of lesions. Group 5 and 6 with lower pH at similar degree of saturation showed remineralization to the body of lesions while group 7 didn't show it. Unlike in Group 3 and 4, Group 5 and 6 showed that each particle was densely distributed with clear appearance rather than crystals form clusters together.

• Journal of dental hygiene science
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• v.6 no.4
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• pp.303-307
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• 2006

The objective of this study was to evaluate the effects of the topical application of fluoride by iontophoresis on the fluoride concentration in the dental enamel. Eighty-eight healthy teeth were extracted from orthodontic patients and divided into three experimental groups at 0.2 mA and 0.5 mA current and a control group. Each experimental group was further divided into three subgroups according to the application time (1, 3, and 5 min). Five to six teeth were assigned to each subgroup. Inotophoresis was performed using a 2% sodium fluoride solution and each tooth was sliced into a $3{\times}3mm$ specimen on enamel. The fluoride concentration in the enamel was measured using X-ray photoelectron spectroscopy. It was used to estimate the atomic ratio of fluoride on the enamel surface on selected samples. The specimen was observed via scanning electron microscopy as well. This finding was confirmed by the result that the fluoride ratios estimated by x-ray photoelectron spectroscopy was 2.71%, 2.87% and 3.80% after fluoride iontophoresis had been performed using a 2% sodium fluoride solution at 0.5 mA for 1, 3 and 5 min, respectively. In comparison, the fluoride ratio was 0.49% in the control group. As the current became higher and the time lapsed, the formation of irregular particles was strengthened on the enamel surface. Afterwards, the enamel surface was dissolved and new matrix was formed on the enamel. Fluorapatite was observed on the enamel after fluoride iontophoresis was performed at 0.5 mA for 5 min. The fluoride concentration tended to increase with increasing duration of iontophoresis. The study findings indicated that under proper conditions, fluoride iontophoresis has a positive effect in increasing the fluoride concentration in dental enamel.

• The korean journal of orthodontics
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• v.31 no.6 s.89
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• pp.567-578
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• 2001

To investigate the difference of Texture exhibited on interproximal enamel surface with each different stripping method and the susceptibility of proximal enamel to demineralization after stripping and the application of a topical fluoride go] and sealant, one hundred human premolars, which were Previously extracted for orthodontic reasons were evaluated by means of Scanning electron microscopy and laser fluorescence. The results were as follows : 1. No matter what the initial stripping instrument was the furrows that resulted from all the stripping methods were not completely removed by careful polishing. 2. Among the enamel surfaces that were treated with three different initial abrasive instruments, followed by the same polishing method (Sof-$Lex^{(r)}$ disks), the enamel surfaces that were treated with 700 crosscut carbide bur showed the smoothest surfaces. 3. The stripped teeth, no matter what the initial stripping instrument was, were less resistant to initial demineralization than untreated teeth. But no difference in caries susceptibility according to differently stripped methods was found (p<(0.001). 4. Teeth treated with APF-gel or sealant were mote resistant to demineralization than those treated without other treatment after stripping (p<0.001). 5. Comparing groups treated with APF-gel to groups treated with sealant, the former was more resistant to demineralization than the tatter (p<0.05). In conclusion, enamel surfaces that were stripped jnterproximally were less resistant to demineralization even though various attempts were made to produce smooth, self-cleaning enamel surfaces. Therefore, additional treatment-sealant or calcifying/ fluoridating solution To the stripped enamel surfaces is recommended.

• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.423-430
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• 2005

Ameloblasts are responsible for the formation and maintenance of enamel which is an epithelially derived protective covering for teeth. Ameloblast differentiation is controlled by sequential epithelial-mesenchymal interactions. However, little is known about the differentiation and maturation mechanisms. OD314 was firstly identified from odontoblasts by subtraction between odontoblast/pulp cells and osteoblast/dental papilla cells, even though OD314 protein was also expressed in ameloblast during tooth formation. In this study, to better understand the biological function of OD314 during amelogenesis, we examined expression of the OD314 mRNA and protein in various stages of ameloblast differentiation using in-situ hybridization and immunohistochemistry. The results were as follows : 1. The ameloblast showed 4 main morphological and functional stages referred to as the presecretory, secretory, smooth-ended, and ruffle-ended. 2. OD314 mRNA was expressed in secretory ameloblast and increased according to the maturation of the cells. 3. OD314 protein was not expressed in presecretory ameloblast but expressed in secretory ameloblast and maturative ameloblast. OD314 protein was distributed in entire cytoplasm of secretory ameloblast. However, OD314 was localized at the proxiamal and distal portion of the cytoplasm of smooth-ended and ruffle-ended ameloblast. These results suggest that OD314 may play important roles in the ameloblast differentiation and maturation.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.4
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• pp.317-323
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• 2014

Dentinogenesis Imperfecta, with a high incidence rate of 1 : 6 - 8000, is inherited by autosomal dominant genetic transmission. This dental disorder causes discoloration of the teeth and the enamel and dentin show hypoplastic or hypocalcified defects which lead to frequent fractures and rapid attrition. Therefore, timely treatment is necessary for the preservation of the remaining teeth. In this particular case, a 19-year-old patient suffering from Type 1 dentinogenesis imperfecta showed signs of brownish hued teeth with multiple fractures, a loss of vertical dimension, excessive interdental space in the maxillary anterior teeth, and a lack of 5 posterior teeth. To improve the esthetic appearance of the anterior teeth, the vertical dimension was increased. Resin caps were used to alleviate the difficulty of taking an impression of multiple teeth at once. Monolithic zirconia materials used in this case showed high fracture strength and the ability to mask the discoloration of the teeth and therefore, functionally and esthetically favorable results were achieved.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.344-351
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• 2020

Amelogenesis imperfecta (AI) occurs either in isolation or in association with other dental abnormalities and systemic disorder. A rare syndrome associating AI with nephrocalcinosis was named as Enamel Renal Syndrome (ERS; OMIM #204690). This syndrome is characterized by severe enamel hypoplasia, failed tooth eruption, intra pulpal calcifications, enlarged gingiva, and nephrocalcinosis. Nephrocalcinosis is a condition where calcium salts are deposited in renal tissue, and this may lead to critical kidney complications. This rare syndrome shows pathognomonic oral characteristics that are easily detectable at an early age, which proceeds the onset of renal involvement. Pediatric dentists are the first oral health practitioners whom ERS patients will meet at early age. The role of pediatric dentists is critically important for early diagnosis and referral of patients to both nephrologists for renal assessment and geneticists for identification of causative mutation and diagnosis. Early detection of renal involvement may provide chances to prevent further undesired renal complications.