• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.25-33
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• 1983

With electron microscope, author studied on the pulp structure of human primary tooth in shedding stage. Non-carious human primary molar teeth were selected for this study. Using standard methods, specimens were sectioned and examined by light and electron microscope, The results were as follows; 1. In coronal pulp, odontoblasts were replaced by multinucleated odontoclasts, which contained a large number of mitochondria of varying shape and vacuoles in cytoplasm. Where odontoclasts were in contact with tooth surface, the characteristic ruffled border and clear zone were observed. 2. Fibrous tissue with plentiful collagen fibers and fibroblasts was observed adjacent to the dentin in the pulp. Fibroblast contained a number of mitochondria and well-developed rough-surfaced endoplasmic reticulum. 3. Inflammatory cells were observed in the pulp and active fibroblasts could be seen between inflammatory cells. In many cases, cervical epithelium proliferated toward absorbed area. 4. Inflammatory cells consisted of a number of lymphocytes, polymorphonuclear leukocytes, plasma cells and macrophages. Macrophage containing lysosomes in digestive state or phagocyting PMN could be seen. 5. In the primary molar of delayed root resorption, odontoblast layer, zone of Weil and cell-rich zone could be seen at roof of pulp chamber and odontoblast in this area cont과ained some lipid droplets.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.4
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• pp.426-435
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• 2018

The aim of this study was to evaluate the proximal caries detecting ability and identify the optimal cut-off values of two types of laser fluorescence (LF) devices; classic type (DD) and pen type (DDpen). The number of proximal surfaces participated in this study were 164 surfaces in primary dentition and 438 surfaces in permanent dentition. Each tooth surface was sequentially assessed by two types of LF devices, and bitewing radiograph. The radiographs were classified into 3 groups in primary dentition ($pR_0$, $pR_1$, $pR_2$), and 4 groups in permanent dentition ($PR_0$, $PR_1$, $PR_2$, $PR_3$) according to the depth of caries, and used as gold standard. In primary dentition, the area under the curve (AUC) values of DD were 0.851 and 0.890, and those of DDpen were 0.883 and 0.917, respectively in enamel caries and dentin caries. In permanent dentition, the AUC values of DD were 0.762 and 0.886, and those of DDpen were 0.828 and 0.958, respectively in enamel caries and dentin caries. When detecting proximal caries in posterior teeth with LF devices, DDpen is more useful than DD in both primary and permanent dentition. However, in primary dentition, DD can also be useful to detect proximal caries.

• Journal of Periodontal and Implant Science
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• v.46 no.1
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• pp.46-56
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• 2016

Purpose: We evaluated the efficacy of a mouthwash containing potassium nitrate ($KNO_3$) as its main component, along with sodium fluoride (NaF) and cetylpyridinium chloride (CPC). The primary endpoint was the relief of dentin hypersensitivity (DH) against the cold stimuli. The effects on other DH tests and periodontal inflammation were also evaluated. Methods: We used a single-center, double-blind, placebo-controlled, randomized design. A total of 82 patients with DH (40 in the test group, 42 placebo controls) were analyzed using visual analog scales (VASs) for a cold test, a tactile test, a compressive air test, and self-reported pain during daily activities, as well as clinical parameters including plaque index, gingival index, modified sulcular bleeding index (mSBI), gingival recession, and probing depth, which were collected at baseline and after four and six weeks of mouthwash use. Results: VAS scores for cold sensations, tactile sensations, the compressive air test, and self-reported pain significantly decreased from baseline during the six weeks in both groups (P<0.01), and no significant differences between the groups were found. In male patients (10 in the test group and 7 in the control group), both groups showed significant reductions in VAS scores for the cold test over the six weeks, and greater reductions were found in the test group than in the control group between four and six weeks (P=0.01) and between baseline and six weeks (P<0.01). In addition, the mSBI in the test group significantly decreased from baseline during the six weeks (P<0.01), and the changes at four and six weeks from baseline were significantly greater in the test group compared to the control group (P=0.03 and P=0.02, respectively). Conclusions: A mouthwash containing a mixture of $KNO_3$, NaF, and CPC reduced DH and gingival inflammation, however, the efficacy was comparable to the control group.

• Restorative Dentistry and Endodontics
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• v.46 no.2
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• pp.17.1-17.9
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• 2021

Objectives: In recent in vitro study, it was reported that osteostatin (OST) has an odontogenic effect and synergistic effect with mineral trioxide aggregate (MTA) in human dental pulp cells. Therefore, the aim of this study was to evaluate whether OST has a synergistic effect with MTA on hard tissue formation in vivo. Materials and Methods: Thirty-two maxillary molars of Spraque-Dawley rats were used in this study. An occlusal cavity was prepared and the exposed pulps were randomly divided into 3 groups: group 1 (control; ProRoot MTA), group 2 (OST 100 μM + ProRoot MTA), group 3 (OST 10 mM + ProRoot MTA). Exposed pulps were capped with each material and cavities were restored with resin modified glass ionomer. The animals were sacrificed after 4 weeks. All harvested teeth were scanned with micro-computed tomography (CT). The samples were prepared and hard tissue formation was evaluated histologically. For immunohistochemical analysis, the specimens were sectioned and incubated with primary antibodies against dentin sialoprotein (DSP). Results: In the micro-CT analysis, it is revealed that OST with ProRoot MTA groups showed more mineralized bridge than the control (p < 0.05). In the H&E staining, it is showed that more quantity of the mineralized dentin bridge was formed in the OST with ProRoot MTA group compared to the control (p < 0.05). In all groups, DSP was expressed in newly formed reparative dentin area. Conclusions: OST can be a supplementary pulp capping material when used with MTA to make synergistic effect in hard tissue formation.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.14 no.1
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• pp.31-35
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• 2018

Dentinogenesis imperfecta is a hereditary disorder that causes abnormal dentin formation and tooth morphology. Affected teeth show very thin dentin and large pulp chamber. Immediately after their eruption, the teeth tend to be destroyed rapidly. Early dental intervention is recommended to improve the feeding capacity and quality of life for the child, to maintain vertical dimension, and to promote healthy and functional dentition. This case report describes a treatment for a 4-year-2-month-old girl whose primary and permanent dentition were affected by Dentinogenesis Imperfecta. Shell teeth were observed in the entire primary dentition. The pulp of most teeth was exposed and the patient complained of pain. Most paternal family members were transferred to the Dentinogenesis Imperfecta. She needed an extensive dental treatment, but her compliance could not be expected because she was very young and anxious. So we decided to treat her under general anesthesia. All molar teeth are restored with Stainless Steel crown. Maxillary anterior teeth were extracted and mandibular anterior teeth are restored with composite resin. The patient's pain disappeared and masticatory function was restored.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.2
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• pp.210-216
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• 2002

Air abrasion technology can prepare enamel and dentin for bonding, similar to etching by acidic gels and solutions. Longer treatment can excavate pit and fissures, preparing the tooth for immediate placement of bonded resin materials. Although not appropriate for every clinical situation, the air abrasive technology minimizes heat, vibration and bone-conducted noise associated with conventional means of caries removal since the cutting is accomplished by air pressure. Also, patients treated with the air-abrasion technology rarely request anesthesia. Air abrasion technology was more effective in treating early carious lesions and stains compared to lesions where caries had already progressed to produce soft dentin and the strong air stream and noise caused by the evacuation system was a major discomfort to pediatric patients, and the experience and skillfulness of clinician should be required for accurate and proper tooth preparation.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.19-26
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• 1997

Odontodysplasia is a rare developmental anomaly of tooth formation in which hard tissue are affected. Odontodyplasia affects the primary and permanent dentitions in the maxilla, mandible, or both jaws. The maxilla is involved twice as often as the mandible. The condition is more common in female than in male patients and in the anterior than in the posterior regions. The clinical manifestation of odontodysplasia are hypoplasia and hypocalcification of the enamel and dentin of affected teeth. Teeth tend to be small and discolored, with short roots and widely open pulp canal. Delayed eruption of affected teeth with abscess formation is common. Radiographically teeth assume a faint radiolucent image ("ghost teeth"). enamel and dentin appear thin and are similar in radiodensity. The pulp chambers are often larger than normal, calcifications(pulp stone and denticle) are found within them. The etiology of regional odontodysplasia is unknown. However, several causes have been discussed, including somatic mutation, local circulatory disorders, local trauma, failure of migration and differentiation of neural crest cells, local infection.

• International Journal of Oral Biology
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• v.31 no.4
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• pp.135-140
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• 2006

Temperature signaling can be initiated by members of transient receptor potential (thermo-TRP) channels. Hot and cold substances applied to teeth usually elicit pain sensation. Since odontoblasts constitute a well-defined layer between the pulp and the mineralized dentin, being first to encounter thermal stimulation from oral cavity, they may be involved in sensory transduction process, in addition to their primary function as formation of dentin. We investigated whether thermo-TRP channels are expressed in a odontoblast cell line, MDPC-23. The expressions of thermo-TRP channels were examined using reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, fluorometric calcium imaging. Analysis of RT-PCR revealed mRNA expression of TRPV1, TRPV2, TRPV4 and TRPM8, but no TRPV3, TRPA1. Immunohistochemical approach failed to detect TRPV1 expression. Whereas the application of 4-phorbol-12,13-didecanoate($10\;{\mu}M$, a TRPV4 agonist), menthol(1 mM, a TRPM8 agonist) and icilin($10\;{\mu}M$, a TRPM8 agonist) produced the enhancement of intracellular calcium concentration, capsaicin($1\;{\mu}M$, a TRPV1 agonist) did not. Our results suggest that subfamily of thermo-TRP channels expressed in odontoblasts may serve as thermal or mechanical transducer in teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.569-578
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• 2007

This study was performed to compare the shear bond strength of self etching system and two bottle bonding system with or without laser preparation. Group I was prepared with high speed rotary instrument and $Prompt^{TM}$ L-$Pop^{TM}$, group II with Er:YAG laser and $Prompt^{TM}$ L-$Pop^{TM}$, group III with Er:YAG laser, 37% phosphoric acid and Single bond, group IV with Er:YAG laser and Single bond and group V with high speed, etching and Single bond. And also observation of the prepared and etched dentin surface were performed under scanning electro-microscope. The possibility of clinical application of laser preparation which might have an advantage to reduce pain for children with less unfavorable noise were evaluated. The results obtained are as follows; 1. Group V showed significantly higher bond strength than other groups. And group IV showed significantly lower bond strength than other groups. 2. There was no significant difference between group I and group III. 3. Group II showed significantly lower bond strength than group I, III, V, but showed significantly higher bond strength than group IV. 4. Under scanning electro-microscope, laser-preparated dentin surface showed high irregularity and no smear layer. The surface showed less irregularities and more exposed dentinal tubules with etching. Laser preparation has many advantages over conventional tooth preparation. But this method showed lower resin bonding strength. Laser preparated tooth surface differed from the conventionally preparated tooth surface. More researches are needed on suitable methods for laser preparated dentin surface.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.3
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• pp.590-596
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• 1997

Ankylosis is defined as a fusion of alveolar bone with dentin and/or cementum and may occur at any time during or following active eruption. Ankylosed teeth maintain existing occlusal levels while adjacent teeth continue to erupt via deposition of alveolar bone. This may result in the clinical appearance of depression or submergence of ankylosed teeth below the occlusal plane. It is found more frequently in children of late mixed dentition and in mandibular primary molars. The problems arising from ankylosed teeth, due to their submerged positions, are elongation of the antagonist, tipping of the adjacent teeth, loss of arch length, food impaction and subsequent destruction of periodontal tissue, disturbance of succedaneous tooth eruption. The author observed several cases of ankylosed primary molars and properly managed. Following results were obtained. 1. Severe infraoccluded ankylosis results in loss of arch length and undesirable effect on eruption path of succedaneous tooth, therefore early diagnosis and management are important. 2. The teeth without problems may be examined periodically and restored in order to maintain the normal occlusal function.