• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.2
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• pp.176-184
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• 2024

This study aimed to compare color matching between single-shade composite resin-restored teeth with various pulp capping materials and the dentin surrounding the restoration through instrumental analysis and visual evaluation of the color difference. Fifty maxillary right central incisor acrylic resin teeth were prepared with standardized Class III cavities on the proximal surfaces. These teeth were divided into five groups: restored with single-shade composite resin only; Ultra-Blend^TM plus followed by single-shade composite resin; TheraCal PT^TM followed by single-shade composite resin; Endocem^® MTA premixed followed by single-shade composite resin; and Well-root PT^TM followed by single-shade composite resin. The color difference (ΔE_ab^*) between the restored area and the center of the resin teeth was measured using a spectrophotometer. No significant color difference was observed in groups restored with only single-shade composite resin, Ultra-Blend^TM plus, and TheraCal PT^TM. The visual evaluation revealed that Ultra-Blend^TM plus exhibited the best color matching score, whereas the Endocem^® MTA premixed and Well-root PT^TM groups showed significantly lower color matching scores than the single-shade composite resin-only group. When opting for single-shade composite resin usage for anterior tooth restorations with the aim of reducing chair time, pulp capping materials Ultra-Blend^TM plus and TheraCal PT^TM provide esthetically pleasing results.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.47-61
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• 2004

Although the purpose of orthodontic treatment is to increase the function and esthetics of the jaws along with increasing stability, there are many side effects during the treatment itself, such as root resorption and alveolar bone resorption. Such resorption of the apical root Is unpredictable, and may even proceed into the dentin layer. Once the process has begun, it is irreversible. By evaluating the effect of many oral habits, especially that of nail biting, in correlation with the root and the periodontal tissues, the appropriate biomechanics for orthodontic treatment can be taken into consideration, along with the possibility of root resorption and alveolar bone loss during orthodontic treatment, and any legal problems that might occur. Among the male and female patients of the ages $10\~15$ without skeletal deformity, 63 were chosen as the experiment group with known nail biting habits at time of examination, and within the same age group without nail biting habits as the control. After the orthodontic treatment, number of the experiment group was 31 and the control group was 22. The periapical radiographies of anterior teeth were taken and the assesment of the root length and alveolar bone level were taken before(T1) and after(T2) the orthodontic treatment. The results from this study were as follows : 1. Before the orthodontic treatment, average crown-to-root ratio of the experimental group showed noticeably high values in 4 maxillary incisors and mandibular right central incisor. 2. Before the orthodontic treatment, comparing the root length, maxillary and mandibular right central incisors and both mandibular incisors had a smaller value in the experimental group. 3. Before the orthodontic treatment, comparing and evaluating the alveolar bone loss measured from the cemento-enamel junction to the alveolar bone crest, some crestal bone of the experiment group showed greater loss than the control. 4. After the orthodontic treatment, there was shortening of the root length and loss of the crestal bone in both groups. 5. After the orthodontic treatment, the changes of C/R ratio and the shortening of root length were significantly high in the experimental group. 6. After the orthodontic treatment, the level of alveolar crestal bone showed greater loss in the experimental group.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.58-65
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• 2012

The crown-root fracture is defined as a fracture of tooth that contains enamel, dentin and cementum with or without pulp exposure. Generally the fracture lines place obliquely from labial surface, between incisal edge of the crown and marginal gingiva, to palatal surface subgingivally. If the fracture line is located supragingivally, the removal of tooth fragment and supragingival restoration can be performed. In subgingival fracture line, the surgical exposure, orthodontic eruption or surgical eruption can be considered. If the fracture line is too deep to restorate, extraction or decoronation can be selected. In children and adolescents, the extraction should be the last option. Another option to select before extraction is the restoration using fiber-reinforced post and the reattachment of tooth fragment. The fiber-rainforced post enhances the retention and the durability of tooth fragment. The reattachment of crown fragment using resin adhesive system is considered minimal invasive treatment biologically. This case reports the treatment of crown-root fracture using the reattachment of crown fragment and the insertion of fiber-reinforced post.

• Imaging Science in Dentistry
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• v.31 no.3
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• pp.181-184
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• 2001

Thirteen-year-old girl complaining of the swelling and pain on the left midface visited our dental hospital. On the radiographic examination, well-defined radiolucent lesion with hyperostotic border was found in the left maxilla accompanying with the external root resorption of the involved teeth and the displaced second molar. CT showed calcified bodies, thinning of hard palate, inferior orbital wall and lateral wall of nasal fossa, and thinning and perforation of the buccal plate of the maxilla. Enucleation and curettage of the lesion and nasoantrostomy was carried out and histopathologic examination mainly showed a solid tumor tissue composed of odontogenic epithelium and pulp tissues admixed with dentin and enamel formation. And some part of reduced follicular epithelium of tooth germ showed a change mimicking calcifying odontogenic cyst. Taken together, we concluded the lesion is an ameloblastic fibro-odontoma with a change of calcifying odontogenic cyst.

• 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.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.434-439
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• 2013

PURPOSE. The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS. A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of $45^{\circ}$ to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS. FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION. Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the postdentin interface.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.568.1-568
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• 2001

The purpose of our study is new formation of periodontal ligament (PDL) around titanium implants. In this study, we investigated histologically whether cultured periodontal ligament fibroblasts (CPLFs) would form new PDL on titanium implants in beagle dogs. PDL fibroblasts were obtained from upper premolars of dogs and cultured in ${\alpha}-MEM$ supplemented with 10％ FBS. Some CPLFs were cultured on glass-beads-sandblasted titanium specimen. Artificial intradentinal cavities were prepared through alveolar bone to dentin of lower premolars.(omitted)

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.45-51
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• 1982

An endodontically treated tooth is likely to be brittle than a vital tooth. Internal structure of the tooth has been weakened due to a significant removal of dentin by coronal access, canal preparation. There are many controversies concerning with various methods of reinforcing an intact anterior tooth that has endodontic treatment. In this experiment, 128 extracted maxillary anterior teeth were endodontically treated, and prepared with 4 methods of restorations; Composite resin filling with zinc phosphate cement, composite resin filling without zinc phosphate cement, composite resin filling with post, and metal crown with post. An Instron testing machine was used to measure the fracture loads of the specimens. The means of the failure loads for the 4 groups were compared by F-test statistically and the failure modes were observed. The results were as follows; 1. There were no statistically significant difference between the failure loads of the four methods of restoration. 2. Teeth without post were fractured in a horizontal or oblique plane through upper or middle third of the root. 3. In the posted teeth, fractures were occurred around the post. 4. In the metal crowned teeth with post, the fracture were occurred around the post or coronal area.

• Journal of Periodontal and Implant Science
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• v.39 no.4
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• pp.437-441
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• 2009

Purpose: The purpose of this report is to show three cases treated by an intergrated periodontal and restorative dentistry approach. Methods: Three patients with Miller Class Ⅰgingiva recessions associated with cervical lesions were enrolled for treatment. Two patients received a connective tissue graft and resin modified glass ionomer, and one patient was treated with a connective tissue graft, resin restoration. Keratinized gingiva and relative gingival recession were measured. Results: The mean reduction of relative gingival recession was 3.7 mm, and the mean keratinized gingiva increase was 2.5 mm. The percentage of root coverage was 80% in average. No signs of gingival inflammation or bleeding on probing were seen. The patients were satisfied with the final esthetics and had no more dentin hypersensitivity. Conclusions: This report indicates that teeth with Miller ClassⅠ gingival recession associated with cervical lesions can be successfully treated by a connective tissue graft combined with restorative dentistry. However, longitudinal randomized controlled clinical trials must be performed to support this approach.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.597-598
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• 2003

I. Objectives Endodontic success depends on thoroughly cleaned and completely obturated root canal system. Effective cleaning and obturation will be achieved by well shaped canal. Numerous methodologies evaluating the efficacy and safety of canal preparation has been developed and the use of micro-computed tomography(MCT) in endodontic research is one of the latest innovations. This scientific tools could overcome the inherent limitations of other methodologies, and possesses the ability to visualize morphological characteristics in a detailed and accurate manner without destruction of the tooth and offers reproducible data in all three dimensions. The purpose of this study was to determine the optimal master apical file size with less transportation and more efficiency in removing the infected dentin. For this purpose we evaluated the transportation of canal center and change of untouched area after preparation sequentially from ＃25 file through ＃40 file with 3 different instruments：Stainless steel(SS) K-type hand instruments(MANI, Japan), ProFile.04 instruments (Dentply Tulsa Dental, USA) and Lightspeed instruments(Lightspeed Technology, San Antonio, USA) using micro-computed tomography.(omitted)