• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.134-140
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• 2013

Objectives: There has been a growing interest in glass ceramic systems with good esthetics, high fracture resistance and bonding durability, and simplified fabrication techniques using CAD/CAM. The aim of this study is to compare flexural strength before and after heat treatment of two lithium disilicate CAD/CAM blocks, IPS e.max CAD (Ivoclar Vivadent) and Rosetta SM (Hass), and to observe their crystalline structures. Materials and Methods: Biaxial flexural strength was tested according to ISO 6872 with 20 disc form specimens sliced from each block before and after heat treatment. Also, the crystalline structures were observed using field-emission scanning microscopy (FE-SEM, Hitachi) and x-ray diffraction (XRD, Rigaku) analysis. The mean values of the biaxial flexural strength were analyzed by the Mann-Whitney U test at a significance level of p = 0.05. Results: There were no statistically significant differences in flexural strength between IPS e.max CAD and Rosetta SM either before heat treatment or after heat treatment. For both ceramics, the initial flexural strength greatly increased after heat treatment, with significant differences (p < 0.05). The FE-SEM images presented similar patterns of crystalline structure in the two ceramics. In the XRD analysis, they also had similar patterns, presenting high peak positions corresponding to the standard lithium metasilicate and lithium disilicate at each stage of heat treatment. Conclusions: IPS e.max CAD and Rosetta SM showed no significant differences in flexural strength. They had a similar crystalline pattern and molecular composition.

• The Journal of the Korean dental association
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• v.57 no.3
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• pp.149-160
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• 2019

Atrophic alveolar ridge of maxillary anterior area is commonly observed after the extraction of teeth in patients with severely compromised periodontal disease, causing difficulties with implant placement. Successful esthetics and functional implant rehabilitation rely on sufficient bone volume, adequate bone contours, and ideal implant positioning and angulation. The present case report categorized the ridge augmentation techniques using guided bone regeneration (GBR) on the maxillary anterior site by Seibert classification. Case I patient presented for implant placement in the position of tooth #11. The alveolar ridge was considered a Seibert classification I ridge defect. Simultaneous implant placement and GBR were performed. Eight months after implantation, clinical and radiological examinations were performed. Case III patient presented with discomfort due to mobility of the upper maxillary anterior site. Due to severe destruction of alveolar bone, teeth #11 and #12 were extracted. After three months, the alveolar ridge was considered a Seibert classification III ridge defect. A GBR procedure was performed; implantation was performed 6 months later. Approximately 1-year after implantation, clinical and radiological examinations were performed. During the whole treatment period, healing was uneventful without membrane exposure, severe swelling, or infection in all cases. Radiographic and clinical examinations revealed that atrophic hard tissues and buccal bone contour were restored to the acceptable levels for implant placement and esthetic restoration. In conclusion, severely resorbed alveolar ridge of the maxillary anterior area can be reconstructed with ridge augmentation using the GBR procedure so that dental implants could be successfully placed.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.3
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• pp.311-318
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• 2017

Several types of attachments have been used for implant supported and/or retained overdentures. Locator is one of the stud type attachments and it has been generally used. However, the colored matrix is resilient and vulnerable to wear, so frequent post-insertion maintenance is needed. To solve this problem, it is necessary to introduce innovative attachment system. Overdentures using Air Gap attachment (AGA) has improved masticatory function and facial esthetics. AGA is made of metal, so it could be more resistant to wear or friction than the other resilient attachments. Nevertheless, AGA plays a role in stress breakers because it allows movement during denture movement with predetermined gap. In addition, both pre-existing implants and natural teeth were successfully used for connection of AGA. AGA could replace other unsplinted type of attachments. Overdentures using AGA could provide satisfactory result in terms of function, esthetics and retention. However, long term follow up is needed.

• Journal of Dental Rehabilitation and Applied Science
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• v.19 no.2
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• pp.115-124
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• 2003

One of the important things in the full mouth reconstruction is the determination of therapeutic position. Centric jaw relation is used as a therapeutic position for the full mouth reconstruction. There are several techniques associated with recording this position. Five clinically acceptable techniques are as follows: 1) Swallowing or free closure, 2) Chin point guidance, 3) Bimanual method 4) Myo-monitor technique, 5) Anterior deprogrammer. Centric relation obtained utilizing the anterior acrylic resin platform in this case. Another important thing in full mouth reconstruction is provisional restoration. Provisional restorations are an excellent diagnostic instrument, especially in full remain esthetics, phonetics, function, parafunction, and dysfunction after evaluation and acceptance through clinical trial with the provisional restorations should be accurately transferred to the final restorations to ensure the same clinical success. Especially, anterior guidance should be accurately transferred to the final restorations. An accurate anterior guidance is critical for optimal esthetics, phonetics, comfort, function, stress minimization, and longevity of teeth and restorations. To record optimum anterior guidance, customized anterior guide table is used in this case. Considering previously mentioned points, we did successive treatment. And it resulted in a better situation esthetically and functionally. Followings are what we cared in treating a patient in this case. 1) Accurate centric relation recording 2) Accurate transference of anterior guidance to the final restorations.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.393-400
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• 2016

Fixed implant prosthesis and removable implant overdenture are the main treatment options for treating edentulous maxilla with implants. If clinicians select one of the treatment options without accurate diagnosis and evaluation, this may lead to unfavorable treatment result and one would not be able to guarantee successful long term prognosis. In this case, 69 year-old female presented with failed fixed implant prosthesis that was treated in private dental clinic. Since the patient did not want additional insertion of implants and considering factors such as oral hygiene maintenance, splinting effect, and esthetics, the patient was treated with removable implant bar type overdenture using pre-existing implants. The clinical results were satisfactory in the aspect of esthetics and masticatory function, oral hygiene maintenance.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.24 no.1
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• pp.39-48
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• 2015

The critical factors affecting the esthetics of anterior implants can be summarized as following: 1) Correct positioning of implant fixture, 2) Enough amount of alveolar bone, 3) Optimum volume of soft tissue. The position of implant is probably the most important factor in obtaining esthetic treatment outcome. The 3-dimensional orientation of implant is determined by the position on the alveolar ridge and its direction. Clinicians often try to mimic natural teeth when fabricating restorations. During the course of esthetic diagnosis and treatment, however, one should not forget to consider the correlation between facial pattern, lips, gingiva, alveolar ridge, as well as remaining dentition. Since anterior region is biologically unfavorable when compared with posterior region, one minor discrepancy in positioning of implant can cause esthetically undesirable treatment outcome. If one understands the biological and prosthetic meaning of implant' s 3-dimensional position, he or she can achieve superior esthetic outcome in anterior region.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.339-349
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• 2014

If the maxillomandibular relationship is unstable or requires treatment for improved function and esthetics, the first treatment objective is to provide stable occlusal contacts. The patient has moderate mental retardation. Due to inadequate vertical overjet, horizontal arch malrelation and excessive tooth loss, full mouth rehabilitation was required. The purpose of treatment planning is to establish physiologic maxillomandibular relation. Using cephalometrics for occlusal analysis is an aid to make a decision. The amount of horizontal bone reduction was calculated with evaluating soft tissue profile. After provisional denture placement, healing of the surgical site and newly adapted arch relationship was evaluated. The patient satisfied with esthetics and showed stable holding contacts. Periodic examination is needed to exclude occlusal disharmony.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.223-235
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• 1998

The recognition of the esthetics as well as their function of the teeth in the dental field is growing. Evaluating the esthetics of a tooth concerns shape, texture, and color. And among these, color has been the most difficult element to make natural expression. Color is a very subjective element affected by many different factor like light source, object, observer. Numerous efforts to quantifying color has been made. Currently the use of colorimeter and spectrophotometercolor that the color measuring device has been suggested. In this study, the normal range of the tooth color in canines, lateral incisors and central incisors for Koreans was evaluated with a modified spectrophotometer for intraoral use. The color differences in terms of teeth positions, age and area within the tooth was evaluated and comparatively analyzed. Results were as follow ; 1. In all age groups, the central incisors are most bright and least yellowish opposit to the canines are most dark and yellowish. The central incisors and lateral incisors showed the similar color patterns. 2. In the comparison between gender, it showed that in the 10' s group male have more yellowish, the 20's female have lighter and more redness, the 30's indicated more redness in female and in the 40's the lightness is more in female. 3. With aging, there was no significant change in $L^*$ and $a^*$ coordinates but a shift was in $b^*$ to yellowish in the 30' sand 40's in central incisors. Lateral incisors and canines showed a lighter and more yellowish tooth color with an irregular change of color coordinate in $a^*$. 4. In all teeth the middle and cervical portion showed close correlation with over 0.7(0.05>p) but color ($a^*$, $b^*$) showed higher correlation than lightness($L^*$). 5. It has been shown that through the regression test the cervical color could be calculated by the middle color value.

• Restorative Dentistry and Endodontics
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• v.41 no.3
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• pp.159-166
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• 2016

The purpose of this review was to suggest practical criteria for the clinical translucency evaluation of direct esthetic restorative materials, and to review the translucency with these criteria. For the evaluation of reported translucency values, measuring instrument and method, specimen thickness, background color, and illumination should be scrutinized. Translucency parameter (TP) of 15 to 19 could be regarded as the translucency of 1 mm thick human enamel. Visual perceptibility threshold for translucency difference in contrast ratio (${\Delta}CR$) of 0.07 could be transformed into ${\Delta}TP$ value of 2. Translucency differences between direct and indirect resin composites were perceivable (${\Delta}TP>2$). Universal and corresponding flowable resin composites did not show perceivable translucency differences in most products. Translucency differed significantly by the product within each shade group, and by the shade group within each product. Translucency of human enamel and perceptibility threshold for translucency difference may be used as criteria for the clinical evaluation of translucency of esthetic restorative materials.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.307-313
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• 2017

The object of this case report is to introduce milled zirconia bar and PEKK female part made by CAD/CAM technology for bar attachment implant supported overdenture in maxillary edentulous patients. For over 2 years, in terms of function and esthetics, satisfactory result was obtained. Esthetically and functionally satisfactory results were obtained in periodic follow up check.