• Proceedings of the KACD Conference
• /
• 2001.05a
• /
• pp.247-251
• /
• 2001

;A dental developmental anomaly is defined as an isolated aberration in tooth form, caused by a disturbance or abnormality which occurred during tooth development. There are numerous types of dental anomalies, and a considerable variation in the extent of the defects occurs with each type. Teeth with these anomalies pose unique challenges. Since the defects are not always apparent clinically, they can confuse diagnosticians investigating the etiology of pulpal pathosis. When endodontic treatment is required, the defects often hinder access cavity preparation and canal instrumentation. Treatment planning also becomes more challenging, since the defects can create complicated periodontal problems, and the malformed teeth can be difficult to restore, particularly those weakened by endodontic therapy. Fusion is defined as the joining of two developing tooth germs resulting in a single large tooth structure. The incidence of fusion is < 1% in the Caucasian population, and it is believed that physical force or pressure produces contact of the developing teeth. Clinically and radiographically, a fused tooth usually appears as one large crown with at least partially separated roots and root canals. There may be a vertical groove in the tooth crown delineating the originally separate crowns. Dens invaginatus is a deep surface invagination of the crown or root that is lined by enamel. Teeth in both maxillary and mandibular arches may be affected, but the permanent maxillary lateral incisor is the tooth most commonly involved. Studies have revealed an incidence ranging from 0.25% to as high as 10%. The invagination ranges from a slight pitting to an anomaly occupying most of the crown and root. The invagination frequently communicates with the oral cavity, allowing the entry of irritants and microorganism either directly into pulpal tissues or into an area that is deparated from pulpal tissues by only a thin layer of enamel and dentin. This continuous ingress of irritants and the subsequent inflammation usually lead to necrosis of the adjacent pulp tissue and then to periapical or periodontal abscesses. If the invagination extends from the crown to the periradicular tissue and has no communication with the root canal system, the pulp may remain vital. Recommended treatment of fused tooth and dens invaginatus has been reported in the endodontic literature. This case report describes the endodontic treatment of a maxillary laterl incisors having fused crown and dens invaginatus.natus.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.42 no.2
• /
• pp.126-135
• /
• 2015

The purpose of this study was to evaluate the skeletal and dentoalveolar effects of facemask therapy and to compare the anchorage of a bonded expander in patients with Class III malocclusion and different vertical skeletal patterns. Twenty subjects with Class III malocclusion were included in this study and were treated with a facemask and bonded expander. Based on the FMA, subjects were divided into two groups of 10 patients each: a high vertical group (HV; mean FMA $33.56^{\circ}$) and an average vertical group (AV; mean FMA $24.88^{\circ}$). Lateral cephalograms were taken and evaluated before and after treatment. In both groups, forward movement of the maxilla and backward rotation of the mandible were observed after treatment, with no statistical differences between the groups. Vertical skeletal variables increased in both groups, but the increase of FMA was significantly larger in the HV group than the AV group. Mesial movement of maxillary molars and proclination of maxillary incisors which indicate anchorage loss of bonded expander were observed in both groups, with no significant differences between the groups. In conclusion, facemask therapy resulted in effective maxillary protraction in both HV and AV groups. However, the open bite tendency was increased more in the HV group.

• The Journal of Advanced Prosthodontics
• /
• v.5 no.3
• /
• pp.219-225
• /
• 2013

PURPOSE. Few studies have investigated the marginal accuracy of 3-unit zirconia fixed partial dentures (FPDs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) system. The purpose of this study was to compare the marginal fit of zirconia FPDs made using two CAD/CAM systems with that of metal-ceramic FPDs. MATERIALS AND METHODS. Artificial resin maxillary central and lateral incisors were prepared for 3-unit FPDs and fixed in yellow stone. This model was duplicated to epoxy resin die. On the resin die, 15 three-unit FPDs were fabricated per group (45 in total): Group A, zirconia 3-unit FPDs made with the Everest system; Group B, zirconia 3-unit FPDs made with the Lava system; and Group C, metal-ceramic 3-unit FPDs. They were cemented to resin dies with resin cement. After removal of pontic, each retainer was separated and observed under a microscope (Presize 440C). Marginal gaps of experimental groups were analyzed using one-way ANOVA and Duncan test. RESULTS. Mean marginal gaps of 3-unit FPDs were $60.46{\mu}m$ for the Everest group, $78.71{\mu}m$ for the Lava group, and $81.32{\mu}m$ for the metal-ceramic group. The Everest group demonstrated significantly smaller marginal gap than the Lava and the metal-ceramic groups (P<.05). The marginal gap did not significantly differ between the Lava and the metal-ceramic groups (P>.05). CONCLUSION. The marginal gaps of anterior 3-unit zirconia FPD differed according to CAD/CAM systems, but still fell within clinically acceptable ranges compared with conventional metal-ceramic restoration.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.32 no.1
• /
• pp.158-163
• /
• 2005

It is rare that the complete avulsion, intrusive luxation, and extrusive luxation occurred by trauma at the same time. In July, 2003, 10-year and 2 month-old-girl was referred to Department of Pediatric dentistry, Chonnam National University Hospital due to complete avulsion of upper right lateral incisor, intrusive luxation of upper right cental incisor and extrusive luxation of upper left central incisor. Traumatized teeth were surgically repositioned and fixated with resin-wire splint at the same day. Endodontic treatment of avulsed tooth was performed 2 weeks after trauma. A radiograph was taken 3 months after trauma, which demonstrated root resorption of both upper central incisors. External root resorption was arrested by the root canal therapy with calcium hydroxide. It showed good results for 1 year and 4 month but further follow-up is needed to check root resorption and ankylosis.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.43 no.2
• /
• pp.192-199
• /
• 2016

Triple tooth is rare in primary dentition; it is the abnormal fusion of three teeth. There are a few reports of double teeth, but triple teeth are rare. These multiple teeth create several clinical problems, not only esthetic problems but also a high caries susceptibility, congenital missing permanent tooth germ(s), orthodontic problems, and periodontal problems. They also make it difficult to perform pulp treatment because of the complex tooth structure. A 1-year 7-month-old male underwent a partial pulpotomy with mineral trioxide aggregate (MTA) when pulp exposure caused by deep caries occurred at a maxillary anterior triple tooth in the first case. The second case was a 1-year 9-month-old male presenting with a fracture line at a mandibular anterior triple tooth. After removing the fractured fragment, a pulpectomy was performed at the remaining primary lateral incisors. Specific complications were not observed during 24 and 6 months of follow-up, respectively.

• The korean journal of orthodontics
• /
• v.23 no.2 s.41
• /
• pp.165-177
• /
• 1993

Upper canine is important because it protects and maintains the stability of the dental arch and also, joins the anterior with the posterior teeth. The incidence of impaction of upper canine is the second most frequent next to the third molar because it takes a long period of time to develop, and has a complicated path of eruption, and erupts lately. After the age of 10, clinical and radioglaphic examination can be used in revealing the possibility of impaction and efforts should be put to reduce the side effects. To prevent impaction, selective extraction of primary canine at the age of 8 to 9 could be considered and prolonged retention of primary canine in oral cavity should be avoided at this time. Once the impaction is iden, the first stage of the treatment is to lcocalize the lesion by radiographic examination and According to the severity, orthodontic traction or autotransplantation should be considered and comprehensive diagnosis and treatment plan of malocclusion should be established. Generally, labial impaction is due to arch length discrepancy and palatal impaction is due to malposition or morphologic pathosis of lateral incisors rather than arch length discrepancy. In surgical procedure, peridontal problems should be considered and the minimum amount of bone and soft tissue should be reduced and direct bonding method of many attachment methods should be recommended. Especially in traction of labially impacted canine, it should be guided to erupt through the keratinized zone and proper forced magnitude should be applied. The importance of periodontal condition should always be in mind following the patient education to mintain the good oral hygiene at each stage of treatment. Properly managed impacted canine can provide function and esthetic by proper diagnosis and treatment if extraction of canine is not indicated.

• The korean journal of orthodontics
• /
• v.50 no.2
• /
• pp.120-128
• /
• 2020

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes. Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment. In addition, MLF was measured at both time points using the Lip De Cum LDC-110R^® device. Statistical analyses were performed to evaluate changes in clinical variables and MLF and their correlations. Results: Both groups showed similar skeletal patterns, although the extraction group showed greater proclination of the maxillary and mandibular incisors and lip protrusion compared to the nonextraction group at T0. MLF at T0 was comparable between the two groups. The reduction in the arch width and depth and incisor retroclination from T0 to T1 were more pronounced in the extraction group than in the nonextraction group. MLF in the extraction group significantly increased during the treatment period, and this increase was significantly greater than that in the nonextraction group. The increase in MLF was found to be correlated with the increase in the interincisal angle and decrease in the intermolar width, arch depth, and incisor-mandibular plane angle. Conclusions: This study suggests that MLF increases to a greater extent during extraction orthodontic treatment than during nonextraction orthodontic treatment.

• Restorative Dentistry and Endodontics
• /
• v.26 no.2
• /
• pp.180-187
• /
• 2001

The structure of current guides is largely illogical and without any rational use of color ordering. The shade guides are generally made of plastic (rather than the actual composite material) and do not accurately depict the true shade. translucency. or opacity of the composite resin after polymerization. To solve this problem, information based on evaluations of natural teeth and material that use the same method and experimental conditions is necessary. The present investigation measured the color of natural maxillary anterior teeth in vivo and compared the results with those of composite resins. 269 Korean subjects were selected for this study. Intact central incisor. lateral incisor. and canine were selected. The clinical crowns were free of caries or restorations. The middle site of the coronal portion on the labial surface of the tooth was measured by Chroma Meter. The five light activated. resin-based materials (Amelogen, Denfil, Elitefil, Spectrum, Z100) were used in this study. Resin composite was condensed into plastic mold with a diameter of 8mm and a thickness of 4mm. pressed between glass plates to flatten the surfaces. and polymerized using a Visilux II visible light activation unit. The surfaces were polished sequentially on wet sandpaper. Color measurements of each specimen were accomplished by Chroma Meter. A computer program that compares each tooth color with each composite resin color was written and the minimum CIELAB color difference ($\Delta$E$^*$) between tooth and each material was calculated. Under the conditions of this study: 1. Teeth tend to become darker with advancing age. 2. Canines were darker. more yellow. and less green than incisors. 3. The teeth from the women were lighter. more green. and less yellow than the male teeth. 4. In general. composite resins were lighter. more green. and less yellow than teeth. Deficiencies were noted in Hues in YR range. 5. Mean color differences between the five composite resin products and teeth were detectable to the naked eye($\Delta$E$^*$>1.0). 6. In comparing the mean $\Delta$E$^*$ values of materials. Spectrum showed the least followed by Z100, Elitefil, Amelogen, Denfil in increasing order.

• Proceedings of the KACD Conference
• /
• 2003.11a
• /
• pp.623-623
• /
• 2003

I. Objectives The aim of this was to evaluate the use possibility of light curing flowable composite resins as a luting agent for translucent fiber posts. II. Materials and Methods 20 single-rooted maxillary central incisors were selected and crown was sectioned below the cemento-enamel junction to obtain a 13 mm ling root. Root canals were filed, cleaned, and shaped to ＃40 with K-file. Prepared canals were filled with gutta percha and AH26 root canal sealer by lateral condensation method. Teeth were than divided into 4 groups of 5 specimens each. In group 1 and 2, the canal space of each root was enlarged with ＃3 DT Light post preparation drill (Bisco, USA) to a depth of 9mm from the cervical.(omitted)

• Restorative Dentistry and Endodontics
• /
• v.40 no.1
• /
• pp.44-49
• /
• 2015

Objectives: This study compared the ability of several techniques to remove calcium hydroxide (CH) from the root canal and determined the influence of CH residues on the accuracy of the electronic apex locator. Materials and Methods: Root canals of 90 human maxillary lateral incisors with confirmed true working length (TWL) were prepared and filled with CH. The teeth were randomly assigned to one of the experimental groups according to the CH removal technique (n = 14): 0.9% saline; 0.9% saline + master apical file (MAF); 17% ethylenediamine tetraacetic acid (EDTA); 17% EDTA + MAF; 5.25% sodium hypochlorite (NaOCl); 5.25% NaOCl + MAF. Six teeth were used as negative control. After CH removal, the electronic working length was measured using Root-ZX (Morita Corp.) and compared with TWL to evaluate Root-ZX accuracy. All specimens were sectioned longitudinally, and the area of remaining CH (CH) and total canal area were measured using imaging software. Results: The EDTA + MAF and NaOCl + MAF groups showed better CH removal than other groups (p < 0.05). Root-ZX reliability to prevent overestimated working length to be > 85% within a tolerance of ${\pm}1.0mm$ (p < 0.05). There was strong negative correlation between amount of CH residues and EAL accuracy (r = -0.800 for ${\pm}0.5mm$; r = -0.940 for ${\pm}1.0mm$). Conclusions: The mechanical instrumentation improves the CH removal of irrigation solutions although none of the techniques removed the dressing completely. Residues of CH medication in root canals affected the accuracy of Root-ZX adversely.