• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.319-323
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• 2014

In dentistry, the term 'fusion' is used to describe a developmental disorder of dental hard tissues. In the permanent dentition, fusion of a normal tooth and a supernumerary tooth usually involves the incisors or canines. However, a few cases of fusion involving premolars have also been reported to date. We present a rare case in which fusion of the maxillary left second premolar and a supernumerary tooth in a 13-year-old girl was diagnosed using cone beam computed tomography (CBCT, Alphard-3030, Asahi Roentgen Ind. Co., Ltd.). The tooth was bicuspidized after routine nonsurgical root canal treatment, and the separated teeth underwent appropriate restoration procedures. The second premolar and supernumerary tooth remained asymptomatic without any signs of inflammation after a follow-up period of 9 years. Identification of anatomical anomalies is important for treatment in cases involving fusion with supernumerary tooth, and therefore the microscopic examinations and CBCT are essential for the diagnosis. Fused teeth can be effectively managed by the comprehensive treatment which includes both endodontic and periodontal procedures.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.84-89
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• 2012

The radicular cyst is the most common odontogenic cyst which is caused by pulpal inflammation, pulp death, and secondary to trauma or dental caries. Usually, the radicular cyst is asymptomatic, but a secondary inflammation can cause pain, swelling and redness. Getting larger, the radicular cyst can cause facial asymmetry and paresthesia by pressure on nerves. It requires conservative endodontic treatment or surgical approach. When the size of cyst is large or invasion of the adjacent tissue is not expected, cyst enucleation is carried out. And most of the case can be completely cured and shows low recurrence. In these radicular cysts cases, by cyst enucleation or apicoectomy after root canal treatment simultaneously, the infected teeth can be preserved successfully.

• Restorative Dentistry and Endodontics
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• v.31 no.2
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• pp.86-95
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• 2006

The purpose of this clinical study is to assess whether calcium hydroxide as an intracanal medication affects post-treatment pain in teeth especially odontogenic pain which comes from inflammation of the pulp and periradicular tissues when compared with no intracanal medication. From 213 patients who has been treated 237 root canals due to significant pain (moderate-to-severe) we recorded their age, sex, treated tooth, degree of pain, pre-operative states of the tooth. We classified patients into 2 test group; Group 1 (not gain intracanal $Ca(OH)_2$), Group 2 (gain intracanal $Ca(OH)_2$). Through the survey from the patients, we let them write down the occurrence and degree of post-treatment pain in 4hours, 2days, 7days after treatment as none, mild, moderate or severe. The followings were evaluated ; the overall incidence of flare-ups, the overall incidence of post-treatment pain in each group at each time period , the incidence of post-treatment pain in each group at each time period as related to pre-operative states of the teeth These were compared statistically with Chi-square analysis (p < 0.05). Under the condition of this investigation, no difference was observed in the incidence of post-treat-ment pain between the two groups. Therefore, $Ca(OH)_2$ as intracanal medication had no effect on preventing or decreasing the post-treatment pain.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.3
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• pp.255-264
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• 2019

Endodontic treatment of primary molars is a great challenge to the dentists because of their complex morphology. However, there have been limited controlled in vivo studies about filling materials for primary teeth. Hence, the aim of this study is to evaluate and compare histologic responses of different calcium hydroxide canal filling materials that are used in daily clinical practice. Pulpectomies were performed in 132 teeth of the dogs. The root canals were randomly filled with either $Vitapex^{(R)}$ (n = 44), $Metapex^{(R)}$ (n = 44), or $Metapaste^{(R)}$ (n = 44). After 4 or 13 weeks, respectively after operation, the dogs were sacrificed, and teeth were processed for histologic examinations. Inflammatory reaction was evaluated and scored in a blind manner. The Fisher's exact test and Kruskal-Wallis test were used to compare the tested groups. In 4-week-group, all inflammatory responses were in normal range except for fibrosis. In 13-week-group, increased response to various inflammation reaction was shown compared to the 4-week-group. However, there were no statically significant differences between the tested groups in all inflammatory reaction. Overall, there were no significant differences among three materials in responses of apical tissues and all of them showed favorable tissue responses.

• Journal of Veterinary Clinics
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• v.29 no.6
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• pp.474-482
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• 2012

Elongation of cheek teeth roots in pet rabbits is very common, and is associated with malocclusion followed by reduced appetite, salivation, periapical abscess, and epiphora. Conservative methods including medication, drainage, irrigation, tooth trimming, intraoral and extraoral extraction, surgical treatment of periapical abscessation, and diet control have been adapted as the only treatments to resolve elongation of teeth roots. However, remaining challenges include the long-term period of cure and recurrence. This study was performed to investigate the possibility of nonvital pulp therapy on elongation of the mandibular cheek teeth roots in pet rabbits. Thirty-one pet rabbits with dental problems due to root elongation were submitted. Ten pet rabbits among them were treated by nonvital pulp therapy procedures (group A), while the others were treated by conservative methods (group B). Appetite improved within 1-5 days after nonvital pulp therapy and the treatment was discontinued 1 month postoperatively in group A. Abscess occurred in another site not treated with nonvital pulp therapy in only two rabbits. Growth of the mandibular cheek teeth treated with nonvital pulp therapy stopped, resulting in malocclusion, intraoral inflammation from the enamel spur, and abscess of the teeth roots. In the group B rabbits treated with conservative therapy, partial drainage, long term medication, recurrent oral trimming and control of repeated oral inflammation occurred. Consequently, buccotomy or tooth extraction was performed in group B. Owners were satisfied with nonvital pulp therapy preventing dental root abscess and repeated troubles including inflammation and malocclusion and reduction of the treatment period. These results suggest that nonvital pulp therapy can be performed on pet rabbits with elongation of mandibular cheek teeth roots.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.3
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• pp.276-283
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• 2011

Recently, undifferentiated stem cells which exist in dental papillae of immature permanent teeth were newly discovered and these stem cells appear to be the origin of ameloblasts associated with the formation of root dentin. When treating immature permanent teeth, the preservation of these stem cells induce the continuous formation of the root. Therefore, it is reported that minimal invasion to periapical region in immature permanent teeth with periapical inflammation resulted in good-healing pattern in clinical and radiographic examination. In this case, a 10 year-old boy(mandibular right premolar) and a 8 year-old girl(maxillary left premolar) who visited the department of pediatric dentistry at Chosun University Dental Hospital were diagnosed with pulp necrosis and periapical abscess in clinical and radiographic examination. Endodontic instrumentation to the periapical region was limited and MTA(Mineral Trioxide Aggregate) was applied into the pulp canal. The periodic checks showed healing of periapical abscess and the development and growth pattern of roots. In permanent teeth with pulp necrosis and periapical abscess, preservation of pulp and dental papillae in the periapical region showed good prognosis during the periodic examinations. Therefore, a lot of clinical examination and long-term evaluation of conservative pulp treatment in immature permanent teeth are expected to be necessary.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.318-332
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• 2000

The purpose of this study was to investigate the effects of demineralized freeze-dried bone (DFDB) on mechanically exposed pulp of dog by evaluating the pulpal inflammation and healing process, formation of dental hard tissue, and structural changes of fibroblasts of the remaining pulp tissue. Teeth of 4 dogs, weighing 10kg, were used in this study. Class V cavities were prepared followed by exposed the pulp tissue mechanically by sterilized round bur. In control group, exposed pulps were capped with calcium hydroxide paste followed by sealed with IRM. In experimental groups, the exposed pulps of one group were capped with the collagen and those of the other group were capped with DFDB. All cavities were sealed with same manor as control group. The animals were sacrificed at the intervals of 3, 7, 14, and 28 days for histopathlogic evaluation. The specimens were observed by the light microscope and trans-electron microscope. The results were as follows: 1. Pulp necrosis was not observed in all groups. Inflammatory response was disappeared from 1 week in control group and group 2. But it was not disappeared until 2 weeks and also irregular arrangement of odontoblasts was showed at the lateral walls of root canal just beneath the amputated site of the pulp in group 1. 2. Dentinal bridge was formed incompletely at 2 weeks but it was formed completely at 4 weeks in control group. Odontoid tissue was also found in control group at 4 weeks from treatment. Amputated site of pulp was encapsulated with fibrous tissue and odontoblast and dentinal bridge was not found in group 1. Preodontoid tissue and reparative dentin which were formed by odontoblast differentiated around DFDB were found, but dentinal bridge was not found in group 2. 3. Cell with large basophillic-stained nuclei infiltrated to amputated site and DFDB at 1 week from treatment in control group and group 2. They were found more in group 2 than in control group. Odontoblasts arranged more regularly and reparative dentin was found more as time elapsed. 4. Dentin-formative odontoblasts which showed ultramicrostructure of cytoplasm with polarized nucleus, rEM, Golgi complex, secretory granules, secretion of organic matrix in control of group and group 2. In regards to above results, the demineralized freeze-dried bone(DFDB) induce odontoblastic differentiation and further come up to the dentin formation in amputated pulp.

• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.470-478
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• 2004

The purpose of this study is to monitor the secretion of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) produced by human osteosarcoma cell line (MG63) stimulated with Prevotella nigrescens lipopolysaccharides (LPS). and to compare the level of secretion before and after the treatment of calcium hydroxide on P. nigrescens LPS. LPS was extracted and purified from anaerobically cultured P. nigrescens. MG63 cells were stimulated by the LPS (0, 1, $10{\;}\mu\textrm{g}/ml$) or LPS($10{\;}\mu\textrm{g}/ml$) pretreated with 12.5 mg/ml of $Ca(OH)_2$ for 3 days. Total RNA was isolated from the cell. and real-time quantitative polymerase chain reaction (PCR) was performed for quantification of MMP-1 and TIMP-1. The results were as follows. 1. MMP-1 mRNA expression at 48 hr was highly increased by stimulation with P. nigrescens LPS. The increase was dose-dependent. 2. When stimulated with ($1{\;}\mu\textrm{g}/ml$ of LPS. TIMP-1 mRNA expression was highly increased at 24 hr and 48 hr. However. TIMP-1 expression was suppressed at higher concentration ($10{\;}\mu\textrm{g}/ml$). 3. When P. nigrescens LPS was pretreated with $Ca(OH)_2$. MMP-1 and TIMP-1 gene expression was downregulated. The results of this study suggest that transcriptional regulation of MMP-1 and TIMP-1 by P. nigrescens LPS could be one of the important mechanisms in bone resorption of periapical inflammation. The result of calcium hydroxide on MMP-1 and TIMP-1 gene expression suppression shows that calcium hydroxide detoxified bacterial LPS and thus should be used the medication of choice for intracanal dressings in root canal infected with black-pigmented bacteria.