• Journal of Korean Dental Science
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• 제14권2호
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• pp.69-78
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• 2021

Purpose: The primary objective of this study was to evaluate the change in the temperature of the adhesive resin in polycrystalline ceramic brackets irradiated using a diode laser at different irradiation energy levels and times. Materials and Methods: For the measurement of the temperature of the adhesive resin, it was applied at the base of the ceramic bracket, a thermocouple was placed at the center of the base surface, the bracket was placed on prepared resin specimens for light curing, and a laser was irradiated to the center of the bracket slot at 5, 7, and 10 W. For the measurement of the temperatures of the enamel under the bracket and pulp cavity, extracted premolar was fixed to a prepared mold and the ceramic bracket was bonded to the buccal surface of the premolar. The Kruskal-Wallis H test and Friedman test were used for statistical analysis. Result: At 5 W, the temperature of the adhesive resin did not reach the resin softening temperature of 200℃ within 30 seconds. At 7 W, it reached 200℃ when the ceramic bracket was irradiated continuously for 28 seconds. At 10 W, it reached 200℃ when the ceramic bracket was irradiated continuously for 15 seconds. During laser irradiation, the temperature of the enamel under the bracket increased by over 5℃ within 15 seconds. Conclusion: The use of diode laser irradiation for bracket debonding should be carefully considered because the pulp cavity temperature increases by over 5℃ within the irradiation time for resin thermal softening.

• Imaging Science in Dentistry
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• 제44권1호
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• pp.43-52
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• 2014

Purpose: This study was designed to evaluate whether magnetic resonance imaging (MRI) is appropriate for detecting early changes in the mandibular bone marrow and pulp tissue of rats after high-dose irradiation. Materials and Methods: The right mandibles of Sprague-Dawley rats were irradiated with 10 Gy (Group 1, n=5) and 20 Gy (Group 2, n=5). Five non-irradiated animals were used as controls. The MR images of rat mandibles were obtained before irradiation and once a week until week 4 after irradiation. From the MR images, the signal intensity (SI) of the mandibular bone marrow and pulp tissue of the incisor was interpreted. The MR images were compared with the histopathologic findings. Results: The SI of the mandibular bone marrow had decreased on T2-weighted MR images. There was little difference between Groups 1 and 2. The SI of the irradiated groups appeared to be lower than that of the control group. The histopathologic findings showed that the trabecular bone in the irradiated group had increased. The SI of the irradiated pulp tissue had decreased on T2-weighted MR images. However, the SI of the MR images in Group 2 was high in the atrophic pulp of the incisor apex at week 2 after irradiation. Conclusion: These patterns seen on MRI in rat bone marrow and pulp tissue were consistent with histopathologic findings. They may be useful to assess radiogenic sclerotic changes in rat mandibular bone marrow.

• Restorative Dentistry and Endodontics
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• 제36권2호
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• pp.149-153
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• 2011

치수는 견고한 치질에 의해 둘러싸여 있기 때문에 치수 혈류나 혈압의 변화는 치수건강에 심각한 위해를 입힐 수 있다. 여러연구에서 치아에 가해지는 교정력이 치수의 혈류 및 세포대사에 변화를 주어 퇴행성/염증성의 치수반응을 일으킬 수 있음이 밝혀졌다. 이 논문의 목적은 만성 치근단 농양을 가진 치아가 명확한 치수생활력 반응을 나타낸 증례에 대해 보고하는 것이다. 이는 치수가 부분적으로 괴사된 상태였기 때문이며 이것의 주 원인은 과도한 교정력인 것으로 판단된다. 남아있는 생활 치수 조직때문에 잘못된 진단이 이뤄지고, 이러한 경우 적절할 치료가 이뤄지지 않음에 따라 괴사조직이 지속적으로 치아주변조직을 파괴하게 될 수 있다. 임상가는 이러한 경우에 있어 여러 진단도구들을 활용하여 정확한 진단을 해야하며 근관-교정 간의 상호작용에 대해 숙지하고 있어야 할 것이다.

• Imaging Science in Dentistry
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• 제51권4호
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• pp.421-427
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• 2021

Purpose: The pulp length to width (PL/W) ratio of the maxillary lateral incisor can be used as an age determination method. This study aimed to investigate the correlation between the PL/W ratio of the maxillary lateral incisor on panoramic radiographs and human chronological age in Indonesian subjects. Materials and Methods: This study analyzed with 134 maxillary lateral incisors on 113 panoramic radiographs from patients who visited the Oral and Maxillofacial Radiology Unit of Dental Hospital Universitas Padjadjaran, Bandung, Jawa Barat, Indonesia, from 2013 to 2018 (age range: between 11 to 60 years). The pulp length was measured from the pulp chamber roof to the apical foramen, and the pulp width was measured on the cervical area of the cementoenamel junction in millimeters using Fiji ImageJ open-source software. Simple linear regression (in SPSS) was used to analyze the results. The reliability of the observers was evaluated. Results: The PL/W ratio of the maxillary lateral incisor was significantly correlated with chronological age (P<0.01). No statistically significant difference was found in the PL/W ratio between the left and right maxillary lateral incisors(P=0.333). There was a very strong correlation (r=0.939) between the PL/W ratio of the maxillary lateral incisor and human chronological age, with the following formula: age= -3.057+1.875×PL/W ratio (R²=0.882, standard error of estimate: 4.659). Conclusion: The PL/W ratio of the maxillary lateral incisor on panoramic radiograph can be used for age determination in Indonesian subjects.

• Journal of Periodontal and Implant Science
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• 제54권2호
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• pp.65-74
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• 2024

Purpose: This longitudinal cohort study aimed to evaluate the relationship between osteonecrosis of the jaw and pulp and periapical disease in patients who were administered bisphosphonates. Methods: Using data from a nationwide cohort, we examined the association among dental caries, pulp and periapical disease, and osteonecrosis of the jaw in women aged >50 years who received bisphosphonates for more than 1 year between 2002 and 2015. Because of ambiguities in the diagnosis of osteonecrosis of the jaw in population-based data, we operationally defined and categorized the condition into established and potential osteonecrosis of the jaw. Results: Pulp and periapical disease significantly increased the development of both established and potential osteonecrosis of the jaw (hazard ratio, 2.21; 95% confidence interval, 1.40-3.48; and hazard ratio, 2.22; 95% confidence interval, 1.65-2.98, respectively). Root canal treatment did not have any influence on the development of osteonecrosis of the jaw. Conclusions: Pulp and periapical disease may be a major risk factor for osteonecrosis of the jaw. The study findings suggest that patients should undergo regular dental examinations to detect pulp and periapical disease before or during the administration of bisphosphonates and that root canal treatment should be considered to decrease the risk of osteonecrosis of the jaw.

• 대한치과의사협회지
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• 제57권1호
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• pp.18-25
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• 2018

Objectives: This study aimed to compare the postoperative pain and clinical performance after partial pulpotomy by using ProRoot MTA and Endocem MTA. Materials and Methods: Twenty-eight teeth requiring partial pulpotomy due to deep dental caries or traumatic injury were included in this study. After 2mm removal of exposed pulp and bleeding control, the ProRoot MTA or Endocem MTA was randomly adjusted to the exposed site. 1, 2, 4, and 12 weeks after the final restoration, the patients were recalled to check the postoperative pain or another unfavorable signs. Pearson's chi-square test was used for statistical analysis to evaluate any differences among tested materials. Results: 3 of 28 teeth showed postoperative pain and cold positive during follow-up period (10.7%). There were no statistically differences in pain occurrence between two tested materials (P > 0.05). Conclusions: In the limitations of this study, partial pulpotomy by using Endocem MTA showed the advantages of short setting time and lower postoperative pain incidence, allowing one visit treatment.

• 대한소아치과학회지
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• 제25권4호
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• pp.843-848
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• 1998

Pulpotomy is a frequently used treatment modality in primary teeth. It is method by which infected coronal pulp is removed while retaining vital radicular pulp. Since its introduction in 1930 by Sweet formocresol remains the most popular medicament for this treatment. However, despite its outstanding bactericidal properties, formocresol is known to cause adverse tissue reactions. Theoretically, formocresol disinfects and fixes radicular pulp and thus prevents infection and internal resorption. In reality, however, it leads to chronic inflammation and is sometimes responsible for failures through abscess formation and internal root resorption. Also, Myers et al., in 1978, reported on the systemic distribution of FC and other studies have followed with reports of its immunological, mutagenic and carcinogenic effects. Much effort has, therefore, focused on the development of alternative medicaments and techniques. Since its introduction in 19C, ferric sulfate proven itself as an effective hemostatic agent and is used as an astringent in dentistry. In 1988, Landau and Johnsen suggested ferric sulfate be used as a medicament in pulpotomy and many studies have focused on it to overcome the toxic effects of FC. Ferric sulfate acts through its ferric ion and iron ion, which react with blood protein leading to aggregation. The aggregated protein acts to plug the blood vessels, causing mechanical hemostasis. As blood clot formation is minimal, there is reduced inflammation of radicular pulp and enhanced healing. There are no reports regarding its systemic distribution. This is a report of cases treated by the author using pulpotomy with ferric sulfate.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제40권4호
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• pp.173-180
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• 2014

Objectives: The purpose of this study was to investigate the neurogenic differentiation of human dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), and stem cells from apical papilla (SCAP). Materials and Methods: After induction of neurogenic differentiation using commercial differentiation medium, expression levels of neural markers, microtubule-associated protein 2 (MAP2), class III ${\beta}$-tubulin, and glial fibrillary acidic protein (GFAP) were identified using reverse transcriptase polymerase chain reaction (PCR), real-time PCR, and immunocytochemistry. Results: The induced cells showed neuron-like morphologies, similar to axons, dendrites, and perikaryons, which are composed of neurons in DPSCs, PDLSCs, and SCAP. The mRNA levels of neuronal markers tended to increase in differentiated cells. The expression of MAP2 and ${\beta}$-tubulin III also increased at the protein level in differentiation groups, even though GFAP was not detected via immunocytochemistry. Conclusion: Human dental stem cells including DPSCs, PDLSCs, and SCAP may have neurogenic differentiation capability in vitro. The presented data support the use of human dental stem cells as a possible alternative source of stem cells for therapeutic utility in the treatment of neurological diseases.

• Imaging Science in Dentistry
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• 제48권3호
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• pp.201-212
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• 2018

Purpose: The aim of this study was to compare cone-beam computed tomography (CBCT) and digital panoramic radiography (DPR) for the detection of pulp stones. Materials and Methods: DPR and CBCT images of 202 patients were randomly selected from the database of our department. All teeth were evaluated in sagittal, axial, and coronal sections in CBCT images. The systemic condition of patients, the presence of pulp stones, the location of the tooth, the group of teeth, and the presence and depth of caries and restorations were recorded. The presence of pulp stones in molar teeth was compared between DPR and CBCT images. Results: Pulp stones were identified in 105 (52.0%) of the 202 subjects and in 434 (7.7%) of the 5,656 teeth examined. The prevalence of pulp stones was similar between the sexes and across various tooth locations and groups of teeth (P>.05). A positive correlation was observed between age and the number of pulp stones(${\rho}=0.277$, P<.01). Pulp stones were found significantly more often in restored or carious teeth (P<.001). CBCT and DPR showed a significant difference in the detection of pulp stones(P<.001), which were seen more often on DPR than on CBCT. Conclusion: DPR, as a 2D imaging system, has inherent limitations leading to the misinterpretation of pulp stones. Restored and carious teeth should be carefully examined for the presence of pulp stones. CBCT imaging is recommended for a definitive assessment in cases where there is a suspicion of a pulp stone on DPR.

• The Korean Journal of Physiology and Pharmacology
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• 제18권1호
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• pp.25-32
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• 2014

Nitric oxide (NO) is recognized as a mediator and regulator of inflammatory responses. NO is produced by nitric oxide synthase (NOS), and NOS is abundantly expressed in the human dental pulp cells (HDPCs). NO produced by NOS can be cytotoxic at higher concentrations to HDPCs. However, the mechanism by which this cytotoxic pathway is activated in cells exposed to NO is not known. The purpose of this study was to elucidate the NO-induced cytotoxic mechanism in HDPCs. Sodium nitroprusside (SNP), a NO donor, reduced the viability of HDPCs in a dose- and time-dependent manner. We investigated the in vitro effects of nitric oxide on apoptosis of cultured HDPCs. Cells showed typical apoptotic morphology after exposure to SNP. Besides, the number of Annexin V positive cells was increased among the SNP-treated HDPCs. SNP enhanced the production of reactive oxygen species (ROS), and N-acetylcysteine (NAC) ameliorated the decrement of cell viability induced by SNP. However, a soluble guanylate cyclase inhibitor (ODQ) did not inhibited the decrement of cell viability induced by SNP. SNP increased cytochrome c release from the mitochondria to the cytosol and the ratio of Bax/Bcl-2 expression levels. Moreover, SNP-treated HDPCs elevated activities of caspase-3 and caspase-9. While pretreatment with inhibitors of caspase (z-VAD-fmk, z-DEVD-fmk) reversed the NO-induced apoptosis of HDPCs. From these results, it can be suggested that NO induces apoptosis of HDPCs through the mitochondria-dependent pathway mediated by ROS and Bcl-2 family, but not by the cyclic GMP pathway.