• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.204-209
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• 2012

Surgical extrusion, immediate extrusion following tooth luxation, is a method to preserve one's natural tooth and achieve esthetic restoration without additional periodontal surgery when subgingival dental caries or crown fracture occurs. A 16-year-old male was referred to the clinic from the department of operative dentistry for the esthetic restoration of maxillary left lateral incisor. Due to the crown to root fracture, the tooth was endodontically treated with a buccal crown length of 4 mm. When the palatal flap was elevated, the mesiopalatal cervical fracture area was situated 3-4 mm subgingivally. Crown lengthening was achieved through surgical extrusion. After 3 months of clinical observation and provisional restoration, the maxillary left central incisor was restored with all ceramic crown and obtained a satisfactory clinical result.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.3
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• pp.571-577
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• 2008

Root fracture of primary teeth is relatively uncommon because the more pliable alveolar bone allows displacement of the tooth. Root fracture of primary teeth is occupied $2{\sim}7%$ in trauma pattern of primary teeth. A horizontal root fracture is classified based on the location of the fracture in relation to the root tip : the apical third, middle third, or cervical third of the root. The prognosis worsens the further cervically the fracture has occurrer. Root fracture of primary teeth should be treated by splinting the incisor to the adjacent normal teeth with a resin-wire splint for $8{\sim}12$ weeks. However, if a portion of the root is abscessed or extremely mobile, it can be extracted, and the remaining root fragment will resorb normally. For coronal third fracture in primary teeth, the coronal third is extracted, leaving the apical portion of the root to resorb normally. These root fracture cases of primary teeth were treated by resin-wire splinting despite extremely mobile coronal fragment. Even though they seems like healing well, They need to be monitored regularly until their successors erupt.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.324-332
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• 2008

Traumatic crown fracture in mixed dentition or early permanent dentition is relatively common. Crown fracture is classified into simple or complicated crown fracture by the presence of pulp exposure. The condition of pulp must be considered in treatment of crown fractures with pulp exposure. Treatment of immature crown-fractured incisor with pulp exposure is more complex because of its incomplete root formation. Pulp capping, partial pulpotomy, cervical pulpotomy can be used for continuous root development in immature crown-fractured incisor with pulp exposure. The success rate of partial pulpotomy is very high and there are several advantages of partial pulpotomy because the cell-rich coronal pulp tissue is preserved. This paper reports 2 cases of crown-fractured permanent incisors with pulp exposure that had been treated by partial pulpotomy successfully.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.125-131
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• 2002

When a tooth is fracture with the pulp exposure, and if a fragment is large enough to save, reattachment of the fragment would be a choice of treatment and reattachment of the fragment provides several advantages over other forms of dental restoration following crown fracture. For the purpose of tooth reattachment, it is important to preserve the sound enamel around fracture area. For young patients, tooth reattachment has more advantages in the sense that they recover faster and that it enables other treatments at the same time. Through the continuous advancement in adhesion technology and the effort for aestheticism, various reattachment methods have been practiced and more efforts are considered necessary. The presented cases are that we had practiced in our department in Kyung Hee Medical center, I may address that fragmentation has been successfully done with aesthetically fine results, and no pathologic changes were found in short term follow-ups.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.9-17
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• 2017

Purpose: The purpose of this study was to evaluate the fracture strength of straight and angled zirconia abutments for internal hex and external hex implants. Materials and methods: Twenty internal hex implants and 20 external hex implants were prepared. The prefabricated straight zirconia abutments and 17-degree-angled zirconia abutments were connected to those 40 implants. The specimens were classified into 4 groups depending on the connection type and abutment angulation; internal hex implant/straight abutment, group INS; internal hex implant/angled abutment, group INA; external hex implant/straight abutment, group EXS; external hex implant/angled abutment, group EXA. All specimens were loaded at a 30-degree angle with a crosshead speed of 1 mm/min using universal testing machine. The fracture loads were analyzed using 2-way ANOVA and independent t-test (${\alpha}=.05$). Results: The mean fracture load for INS was 955.91 N, 933.65 N for INA, 1267.20 N for EXS, and 1405.93 N for EXA. External hex implant showed a significantly higher fracture load, as compared to internal hex implant (P < .001). No significant differences in fracture loads were observed between the straight and angled abutment in internal hex implants (P = .747) and external hex implants (P = .222). Internal hexes of abutments were fractured horizontally in internal connection implants, while lingual cervical neck portions were fractured in external connection implants. Conclusion: The zirconia abutments with external hex implants showed significantly higher fracture strength than those with internal hex implants. However there was no difference in fracture strength between the straight and 17-degree-angled zirconia abutment connected to both implant systems.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.4
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• pp.488-496
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• 2010

Dens evaginatus is a tooth with cylindrical enamel projection which forms a nodule on occlusal surface. It could be explained as outward overgrowth of inner enamel epithelium or localized hyperplasia of pulpal mesenchymal tissue during tooth development. A problem is that it is likely to be worn out or fractured by mastication ensuing pulpal inflammation. It is occasionally found on the lingual surface of upper anterior teeth as well, called talon cusp. Dens invaginatus is a tooth with deep lingual pit made by invagination of lingual enamel epithelium during tooth development while it is considered normal in terms of size and shape. Radiographically, a part of cervical enamel shows inward growth forming cavity and it is reasonable to say that the base is possibly open to pulpal cavity since they are very close. Talon cusp and dens invaginatus are relatively common abnormality of shape. However it becomes the opposite if the two exist in the same tooth. Once the talon cusp is broken by occlusal force or fissure between cusps is decayed, the complicated structure of canals makes the pulpal treatment difficult. Preventive treatments such as occlusal equilibrium and sealant, and regular oral examination should be preceded and thorough understanding of canal shape, using radiography, is required when pulpal treatment is necessary. This report is about a 9- year-old boy(lower left central incisor), a 8-year-old girl(upper right central incisor), and a 7-year-old boy(upper right central incisor), who have dens invaginatus and talon cusp in the same teeth. The first and the second patients are under pulpal treatments, and the last one is being observed showing no pathologic impressions.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.1
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• pp.47-51
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• 2013

With the introduction of dental implants, restoration of missing teeth with conventional fixed or removable partial dentures is being replaced with implants. Especially, with young patients, not only longevity but also esthetic factors need to be considered. Implant restorations provide long-term success functionally but, esthetic complications such as, marginal exposure due to gingival recession, loss of the papilla and dark color of metal abutments may occur. Recently, zirconia restorations with CAD/CAM technology provide functional, biocompatible and esthetic restorations possible. All-ceramic restorations using the pressed ceramic technique show better fracture toughness values than those of the conventional porcelain veneering technique. Pressed ceramic technique creates the veneer design in wax and the lost wax technique is used to create the restoration. The final contour of the restoration may be controlled during wax-up. A 22-year old female patient was restored with dental implants and zirconia restorations using the pressed ceramic technique presenting short-term but optimistic prognosis.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.87-101
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• 2012

Bruxism is extensively defined as a diurnal or nocturnal parafunctional habit of tooth clenching or grinding. The etiology of bruxism may be categorized as central factors or peripheral factors and according to previous research results, central factors are assumed to be the main cause. Bruxism may cause tooth attrition, cervical abfraction, masseter hypertrophy, masseter or temporalis muscle pain, temporomandibular joint arthralgia, trismus, tooth or restoration fracture, pulpitis, trauma from occlusion and clenching in particularly may cause linea alba, buccal mucosa or tongue ridging. An oral appliance, electromyogram or polysomnogram is used as a tool for diagnosis and the American Sleep Disorders Association has proposed a clinical criteria. However the exact etiology of bruxism is yet controversial and the selection of treatment should be done with caution. When the rate of bruxism is moderate or greater and is accompanied with clinical symptoms and signs, treatment such as control of dangerous factors, use of an oral appliance, botulinum toxin injection, pharmacologic therapy and biofeedback therapy may be considered. So far, oral appliance treatment is known to be the most rational choice for bruxism treatment. For patients in need of esthetic correction of hypertrophic masseters, as well as bruxism treatment, botulinum toxin injection may be a choice.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.654-660
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• 2001

Dentinogenesis imperfecta is an example of an inheritable dentinal defect originating during the histodifferentiation stage of tooth development, with involvement of the primary and permanent teeth. Shields, Bixler and El-Kafrawy proposed three types of Dentinogenesis imperfecta : Type I, II, III. Witkop reported a prevalence of 1 in 8000 with the trait, and no significant difference between male and female. Affected teeth have red-brown discoloration often with distinctive wearness of occlusal surface of posterior teeth and incisal surface of anterior teeth. Once enamel seperated from underlying defective dentin, the dentin demonstrates significantly acclerated attrision. Radiographically, the teeth have thin roots, bulbous crown, cervical constriction, and obliteration of the root canals and pulp chambers. In primary dentition periapical lesions or multiple root fractures are often observed. In successive generations the phenotypes of discoloration and wearness of teeth occurred, and one of the patient's subships, 10 year-old sister, showed general discoloration of her teeth and mild wearness. In this case, a 4 year-old male reported to the Yonsei University Pedodontics clinic, with a chief complaint of discolored teeth. The teeth showed generally yellowish-brown discoloration and moderate wearness. In radiographic features, obliteration of pulp, bulbous crown, and short roots were observed. It was diagnosed as Dentinogenesis imperfecta. The posterior teeth were restored with Stainless Steel Crown, and defective incisors including left upper primary central incisor which was extracted due to a root fracture with Open-faced Stainless Steel crown.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.91-95
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• 2009

The use of stainless steel crowns are indicated for restoration of primary or permanent molars with proximal dental caries, extensive dental caries, or previous pulp treatment with increased danger of tooth fracture. Stainless steel crowns were introduced by Humphrey in 1950. For their improved durability, longevity, and success rate, they have been strongly considered for restoring extensive and multi-surfaced dental caries of molars in pediatric dentistry. However, they also have shortcomings, such as possibility of pulpal exposure or damaging proximal surface of adjacent teeth. In addition, when oversized stainless steel crowns are used, eruption of the adjacent permanent teeth may be disturbed by their prominent margin. As a means to compensate the shortcomings of stainless steel crowns, use of orthodontics bands may be considered. It is an alternative restoration method, where an orthodontic band is placed on a tooth first and cavity is restored with filling material, such as composite resin, glass ionomer, or amalgam. The use of an orthodontic band is indicated for molar restoration with cervical dental caries, extensive dental caries, enamel hypoplasia, or previous pulp treatment. Because it requires shorter chair time compared to stainless steel crown, its application is very useful for children with poor behavior. However, restoration using an orthodontic band requires good oral hygiene after its application. This case report illustrates the conservative restoration of primary molars and permanent molars with extensive dental caries using orthodontic bands.