• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.1
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• pp.41-56
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• 2018

The purpose of this study was to provide clinical recommendations for restoration with selection of the most similar zirconia crown by 3-dimensional analysis of the shape of the maxillary primary central and lateral incisors in Korean individuals and prefabricated zirconia crowns. The average shape of the sound maxillary primary central and lateral incisors in 300 children was reproduced by 3-dimensional scanning. Zirconia crowns of 4 manufacturers (NuSmile $ZR^{(R)}$ Crown, Cheng $Crowns^{(R)}$, Kinder $Krowns^{(R)}$, and EZ $Pedo^{(R)}$ Crown) were scanned 3-dimensionally, and coordinates for comparison of the shape were measured to evaluate the similarity between the teeth and crowns. The most similar crowns were selected by comparing the mesiodistal length, crown height, crown shape ratio, distance between the same coordinates of a tooth and crown, the radius of curvature of the labial surface, and the volume. As a result of analysis, Cheng $Crowns^{(R)}$ size 3 and NuSmile $ZR^{(R)}$ Crown size 2 were the most similar crowns in the maxillary primary central and lateral incisors, respectively. Scanning the inner surface of the crowns and evaluating the amount of tooth reduction required suggested that an overall lesser amount of tooth reduction compared to that presented by the manufacturer's guidelines should be performed.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.2
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• pp.197-207
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• 2001

Development of new ceramics and esthetic needs of patients increase the use of all ceramic restorations. Fractured teeth often need metal post and core as foundation for final restoration. When all ceramic restorations are planned, metal post and core may lead to compromised esthetics because of opacity and gray color of metal post and core. Many techniques have been proposed to solve this problem such as application of an opaque porcelain to the metal core or all ceramic post and core. This study was performed to evaluate effect on color of Empress 2 crown according to various post systems. Color was evaluated by the CIE $L^*a^*b^*$ systems and measured by spectrophotometer (Model CM-3500, Minolta, Japan). Specimens were divided into 4 groups as follows Group 1 : gold cast post specimen + Empress 2 crown specimen Group 2 : application of an opaque porcelain to gold cast post specimen + Empress 2 crown specimen Group 3 : cosmopost specimen + Empress 2 crown specimen Group 4 : In-ceram post specimen + Empress 2 crown specimen. The results obtained as follows, 1. $L^*$ Values showed that group 2, 3, 4 were higher than group 1 with significant difference and group 2, 3, 4 were not significantly different. 2. $a^*$ Values and $b^*$ values also showed that group 2. 3, 4 were higher than group 1 with significant difference and group 2, 3, 4 were not significantly different. 3. ${\Delta}E^* ab$ Values showed that ${\Delta}E^* ab$ 3 was the highest value and ${\Delta}E^* ab$ 5 was the lowest value.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.1
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• pp.53-67
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• 2002

This study was aimed to analyze the stress distribution of implant and supporting tissue in single tooth implant restoration using Branemark $system^{(R)}$(Nobel Biocare, Gothenberg, Sweden) and Bicon system(Bicon Dental Implants, Boston, MA). Two dimensional finite element analysis model was made at mandibular first premolar area As a crown materials porcelain, ceromer, ADA type III gold alloy were used. Tests have been performed at 25Kgf vertical load on central fossa of crown portion and at 10Kgf load with $45^{\circ}$ lateral direction on cusp inclination. The displacement and stresses of implant and supporting structures were analyzed to investigate the influence of the crown material and the type of implant systems by finite element analysis. The results were obtained as follows : 1. The type of crown material influenced the stress distribution of superstructure, but did not influence that of the supporting alveolar bone. 2. The stress distribution of ceromer and type III gold alloy and porcelain is similar. 3. Stress under lateral load was about twice higher than that of vertical load in all occlusal restorative materials. 4. In Bicon system, stress concentration is similar in supporting bone area but CerOne system generated about 1.5times eater stress more in superstructure material. 5. In Branemark models, if severe occlusal overload is loaded in superstvucture. gold screw or abutment will be fractured or loosened to buffer the occlusal overload but in Bicon models such buffering effect is not expected, so in Bicon model, load can be concentrated in alveolar bone area.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.256-261
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• 2000

Trauma to the tooth is the most common accidents in pediatric dentistry and tooth fracture occurs frequently. Fracture is classified into crown fracture, root fracture, and crown-root fracture which involves both. Also, it is classified into simple or complicated fracture depending on whether the pulp is exposed or not. When the fracture is extended down to the subgingival level following the long axis of the root, or when more than 1/3 of the root is involved, extraction is the primary treatment. But alternative treatment such as extruding the root fragment with orthodontic force and restoring it, or intentionally extracting the tooth and replanting it to a position which it can be restored. This is a case report on intentional replantation of a traumatized maxillary central incisor with crown-root fracture of a patient with mixed dentition. The teeth was extracted and immediate endodontic treatment, retrograde filling and resin restoration were carried out.

• Journal of Technologic Dentistry
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• v.31 no.1
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• pp.17-21
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• 2009

This experimental study was to determine the fitness on each cervical margin of recast using crown base metal alloy. The alloy used in this experimental study was a Ni-Cr alloy(Wirolloy, Bego, Germany) for the fabrication of full cast crown prosthesis. Twenty-five copings were divided into the five groups. And the group A, B, C, D and E were cording successively according to the frequency of recast to five times. Each specimen was recasted without adding new metal. The experimental results were as follows: 1. The group A and B showed good fitness had subtle differences in each cervical margin adaptation, in other words, the mesio and disto cervical margin showed worse adaptation than the bucco and linguo cervical margin. 2. The group C got good fitness in bucco and linguo cervical margins, but the mesio and disto cervical margin showed inaccurate fitness. And I could not get good casting bodies without adding new metal. 3. The group D and E showed bad fitness for each cervical margin. Therefore the group D and E lost its function as a dental restoration.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.3
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• pp.243-250
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• 2006

Due to high esthetic demands from patients, we are driven to fabricate natural-looking(form and color) restorations. In the past decade, the glass-ceramic in dentistry has been used as a material with variable crystals that affects the appearance, characteristics, and mechanical properties of metal-free fixed restoration. The conventional IPS Empress glass-ceramic is a heat-pressed, leucite reinforced material using the "lost wax" principle. This glass-ceramic has been successfully used for esthetic restorations such as all-ceramic crowns, inlays/onlays, and veneers for about 15 years. This article presents that the form and surface texture of clinical crown are duplicated by IPS-Empress system using "lost-wax technique".

• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.203-208
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• 2016

Purpose: This study introduces the production process of dog's dental prosthesis using an automated dental prosthetics technology. The occlusal interaction of dog's dental prosthesis was observed. Methods: This study was proceeded with dog's the mandibular first molar teeth. The 3D CAD designed to 3D model specimens was observed by CAD software. and The specimens designed to 3D model specimens was observed occlusal interaction by using articulator. Results: Occlusal contact point in prosthetic specimens were observed in buccal surface. and 98% of the size of the crown is the best occlusal relationship. Conclusion: Observation of occlusal relations result to 98% of the size of the crown is the best.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.28 no.2
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• pp.95-115
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• 2019

To be successful in aesthetic prosthetic treatment, the crown part aesthetic (White Esthetic) and the tissue part aesthetic (Pink Esthetic) must be well controlled. Clinically, white esthetics are the area of dental technicians and pink esthetics are the area of dentists, but a deeper understanding of counterparts can produce more successful results. In this paper, I will briefly describe this process.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.199-205
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• 2012

Although the stainless steel crowns have been recognized as the most effective and durable form of restoration for primary molars, they have been regarded by many dentists as having definite demerits such as invasive nature of procedural complexity and behavioral aspects of children. As an alternative to conventional technique of stainless steel crown restoration, the Hall technique was first introduced in 1988, which is characterized by just pushing the pre-contoured, cement filled crown form onto the abutment molar with no local anesthesia, no caries removal, no tooth preparation. According to several reports, this can slow, arrest, or even reverse the progress of caries. In addition, its atraumatic feature gives less discomfort and stress to children than conventional one, which is thought excellent especially in younger children. Also, It has been reported to be effective and acceptable to dentist, child patients and their parents. In this case study, three children with age of 4 years 5 months, 4 years 10 months, 6 years 4 months were treated with stainless steel crowns using Hall technique on first primary molar respectively. The teeth were free from pulpal, periapical pathology. After follow up of about 3 to 6 months period, the results showed clinically successful outcomes without any marked complication in pulp, tooth or soft tissue till now. But, it should be kept in mind that this technique is not proper to every child, every carious molar, or every dentist. Thorough distinction of indicated cases and continuous follow-up check is highly required. Conclusively, Hall technique might be an effective and realistic minimally invasive alternative for the carious primary molars especially in younger or disabled children, despite potential doubts on its efficacy and some definite limitations.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.119-124
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• 2009

Statement of problem: The increasing demand for esthetic restorations has been required developing new materials for tooth colored restoration. Ceromer(Ceramic Optimized Polymer) has some advantages over porcelain, and has gained increasing popularity in restorative dentistry. However, there is little information on the dimensional changes in a clinical restoration in moist conditions. Purpose: This study examined the dimensional changes in Ceromer restorations with a clinical crown shape that were fabricated in a clinical manner. Material and methods: The crowns for the maxillary central incisor were fabricated with two Ceromers($BelleGlass^{(R)}$ and $Targis^{(R)}$) using a similar clinical restoration manufacturing technique. A total of twenty specimens were prepared and immersed in distilled water at room temperature to allow for water absorption. The weight, height and width were measured at 24, 72 and 168 hours. The accumulated ratios of the changes were calculated and evaluated using a paired t-test and an independent independent t-test. Results: The dimensions and weight increased with increasing soaking time. $Targis^{(R)}$ showed significant differences in height and weight between 24 hours and the other times(P<.05). $BelleGlass^{(R)}$ showed significant differences in width and weight between 24 hours and the other times. The two materials showed different changing patterns of the dimensions but there were no statistically significant differences between them. Conclusion: The dimensions and weight of the Ceromer restorations were changed by water absorption. The clinical crown shaped specimen showed more complicated dimensional changes than the simplified specimens.