• Restorative Dentistry and Endodontics
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• v.32 no.5
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• pp.469-475
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• 2007

The purpose of this study was to evaluate the effect of a new resin monomer on the microleakage of composite resin restorations. By adding new methoxylated Bis-GMA (Bis-M-GMA, 2,2-bis[4-(2-methoxy-3-methacryloyloxy propoxy) phenyl] propane) having low viscosity, the content of TEGDMA which has adverse effects on polymerization shrinkage might be decreased. As a result, microleakage might be improved. $2\;mm\;{\times}\;2\;mm\;{\times}\;2\;mm$ cavities with occlusal margins in enamel and gingival margins in dentin were prepared on buccal and lingual surfaces of 40 extracted human premolars. Prepared teeth were randomly divided into four groups and restored with Clearfil SE bond (Kuraray, Japan) and one of experimental composite resins; EX1, Experimental composite resin1 (Bis-M-GMA/TEGDMA = 95/5 wt%, 40 mm nanofillers); EX2, Experimental composite resin2 (Bis-M-GMA/TEGDMA = 95/5 wt%, 20 mm nanofillers); EX3, Experimental composite resin3 (Bis-GMA/TEGDMA = 70/30 wt%, 40 nm nanofillers); and Filtek Z250 (3M ESPE, USA) was filed as a control group. The restored teeth were thermocycled, and immersed in 2% methylene blue solution for 24 hours. The teeth were sectioned buccolingually with a low speed diamond saw and evaluated for microleakage under stereomicroscope. The data were statistically analyzed by Pearson Chi-Square test and Fisher Exact test (p = 0.05). The microleakage scores seen at the enamel margin were significantly lower than those of dentin margin (p = 0.007). There were no significant differences among the composite resins in the microleakage scores within each margin (p > 0.05). Bis-M-GMA, a new resin monomer having low viscosity, might in part replace high viscous Bis-CMA and might improve the quality of composite resin.

• Journal of Periodontal and Implant Science
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• v.47 no.5
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• pp.312-327
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• 2017

Purpose: This study assessed marginal bone remodeling and soft tissue esthetics after the loading of single bone-level implants in the anterior maxilla. Methods: An open, single-arm observational clinical trial with 3 years of follow-up was performed, including 22 implants. The patients presented with a single tooth gap in the anterior maxilla (tooth positions 14-24), with natural or restored adjacent teeth. An implant was placed at least 8 weeks post-extraction and healed submerged for 6 weeks. After the second-stage operation, a fixed provisional prosthesis was provided. The final restoration was placed 6 months after the provisional restoration. The time of the provisional crown connection was considered to be the baseline in this study. Esthetic parameters and the marginal bone level were assessed at 6, 12, 24, and 36 months. Results: All implants were well integrated in the bone. A statistically significant increase was found in the mean implant stability quotient between the time of the provisional prosthesis and the time of the final prosthesis. Most implants (95.5%) revealed marginal bone resorption (<0.5 mm), and just 1 implant (4.5%) showed a change of 2.12 mm from baseline to 36 months (mean $0.07{\pm}0.48mm$), while the crestal bone level decreased significantly, from $2.34{\pm}0.93mm$ at baseline to $1.70{\pm}1.10mm$ at 36 months. The facial gingival margin and papilla were stable and the esthetic scores indicated high patient and dentist satisfaction. Conclusions: Platform-switching bone-level implants placed in maxillary single-tooth gaps resulted in successful osseointegration with minimal marginal bone resorption. The peri-implant soft tissue was also esthetically satisfying and stable.

• Journal of Periodontal and Implant Science
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• v.37 no.1
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• pp.103-113
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• 2007

The purpose of this study was to measure the thickness of masticatory mucosa in the hard palate as a donor site for mucogingival surgery by using computerized tomography(CT), Thickness measurements were performed in 84 adult patients who took CT on maxilla for implant surgery and 24 standard measurement points were defined in the hard palate according to the gingival margin and mid palatal suture. Radiographic measurements were utilized after calibration for standardization. Data were analyzed to determine the differences in mucosal thickness by gender, age, tooth positions and depth of palatal vault. The results of this study were as follows: 1. Mean thickness of palatal masticatory mucosa was $3.93{\pm}0.6mm$ and females had significantly thinner mean masticatory mucosa($3.76{\pm}0.56mm$) than males($4.04{\pm}0.6mm$)(p<0.05). 2. The thickness of palatal masticatory mucosa increased by aging. 3. Depending on position, masticatory mucosa thickness increased from canine to premeolar, but decreased at the first molar, and increased again in the second molar region(p<0.0001). 4. No significant difference in mean thickness of palatal masticatory mucosa were indentified between low palatal vault group and high palatal vault group(p>0.05). The results suggest that canine and premolar area appears to be the most appropriate donor site for soft tissue grafting procedure. The measurement of the thickness of palatal masticatory mucosa by using computerized tomography can offer useful information clinically but further studies in as-sessing the validity and reliability of the method using computerized tomography is needed.

• The Journal of the Korean dental association
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• v.58 no.7
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• pp.435-442
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• 2020

Porcelain is the first ceramic material to be introduced into dentistry. Porcelain jacket crown was introduced by Dr. Charles H Land in 1886, which was an excellent aesthetic dental restoration but has not been widely used due to high firing shrinkage and low tensile strength. Then metal-ceramic system, which combines the esthetic properties of ceramics and the mechanical properties of metals, was introduced and nowadays it is still used in dental clinical field. However, the metal-ceramic system has shown some problems, such as increased lightness by reflection of light at opaque layer, shadow beneath the gingival line due to the block-out of light by metal coping, exposure of metal in margin part, bond failure between metal and porcelain, oxidation of metal coping during firing the porcelain, etc. Recently, along with the advance of fabrication methods of dental ceramics, the all-ceramic restorations with high esthetic and mechanical properties has increased and gradually replaced metal-ceramic restorations. Especially, CAD/CAM technology has opened a new era in fabricating the dental ceramic restorations. This overview will take a look at the past, present and future possibility of the dental ceramic materials.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.259-267
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• 2008

This in vitro study aimed to investigate the influence of flowable composite lining with different thicknesses on the marginal quality. One hundred twenty cavities, each preparated with proximal boxtype( 3mm of bucco-lingual width, 2mm of mesio-distal depth and gingival margin of 1mm supra-CEJ) were randomly dived into four groups. group I : Tetric ceram filling alone(control group) group II: 0.5mm thickness Tetric flow + Tetric ceram filling group III: 1.5mm thickness Tetric flow + Tetric ceram filling group IV: 2.5mm thickness Tetric flow + Tetric ceram filling The followings are the results: 1. Group II showed significantly less microleakage compared to group I(control group)(p<0.05). 2. There was no statistically significant difference between group III, IV and group I(p>0.05). 3. Group II showed significantly less microleakage compared to group III, IV(p<0.05). 4. There was microleakage more or less in all group. It was concluded that 0.5mm flowable composite lining improved cavity adaptation and marginal sealing.

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.1-14
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• 1994

Dental calculus which is calcifing and/or calcified dental plaque is divided into supragingival calculus and subgingival calculus according to the position of deposit to gingival margin. Subgingival calculus has more important clinical significance in diagnosis and treatment of periodontal disease than supragingival calculus. In order to investigate the deposition pattern of subgingival calculus on each root surface of different tooth type, extracted 192 teeth due to excessive destruction of periodontal tissue were divided according to tooth type and the deposition pattern of subgingival calculus was classified into linear type, veneer type, scattered type, and aggregated type according to the configuration and the extent of deposit. The difference of percentage between each deposition pattern was statistically analyzed by Chi-Square test. Following results were obtained : l. In maxillary incisors, linear type and aggregated type were predominant deposition pattern of subgingival calculus on labial(45.5%, 36.4%) and palatal(36.4%, 36.4%) root surface, aggreated type(72.7%) was on mesial surface, and aggregated type(54.5%) and scattered type(36.4%) was on distal suface. 2. In mandibular incisors, scattered type, linear type and aggregated type were predominant deposition pattern of subgingival calculus on labial(33.3%, 30.6%, 27.8%) and lingual(36.1%, 30.6%, 25.0%) root surface, aggregated type(33.3%), scattered type(27.8% ), and veneer type(27.8%) were on mesial surface, and aggregated type(38.9%) and scattered type(33.3%) on distal surface. 3. In maxillary peremolars, the predominant deposition patterns of subgingival calculus were linear type(28.6%) on buccal root suface, scattered type(35.7%) and linear type(28.6%) on palatal surface, scattered type(39.3%) on mesial surface, aggregated type(46.4%) on distal surface, and aggregated type(53.6%) on furcation area. 4. In mandibular premolars, scattered type was predominant deposition pattern of subgingival calculus on buccal(39.3%) and lingual(50.0%) root surface, scattered type(32.1%) and aggregated type(32.1% ) were on mesial surface, and aggregated type(42.9%) was on distal surface. 5. In maxillary molars, aggregated type(40.0%) and scattered type(32.5%) were predominat deposition pattern of subgingival calculus on buccal root surface, aggregated type was on distal(40.0%) and furcation area(50.0%), but there was no predominat pattern on palatal and mesial root surfaces. 6. In mandibular molars, aggregated type(39.5%) and scattered type(28.9%) were predominant deposition patterns of subgingival calculus on buccal root surface, aggregated type(36.8%) was on lingual surface, linear type(39.5%) and aggregated type(34.2%) were on furcation area, but there was no predominant pattern on mesial and distal root surfaces.

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.15-25
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• 1994

Keratinized ginigva has clinical singificance in periodontal health because it plays important roles in resistance to mechanical trauma, to penetration of bacteria, and to tensional stress by muscle attachment. In order to investigate the width change of anterior keratinized gingvial during transitional period, the width of kerainized gingiva on anterior teeth was measured annually in elementary school children with deciduous dentition until the successive anterior teeth were completely erupted. The distance from the gingival margin on mid-portion of crown to mucogingival junction was measured by Boley gauge(Hu-Friedy, U.S.A.) and was recorded as the width of keratinized gingiva. The difference of the width of keratinized gingiva according to sex and dentition was analyzed statistically by Student t-test. Following results were obtained : 1. In deciduous dentition, it was shown that the width of keratinized gingiva on maxillary central incisors($3.28{\pm}0.83mm$) was the widest(p<0.01), and that on maxillary lateral incisors, mandibular central and lateral incisors was $2.69{\pm}0.86mm$, $2.51{\pm}0.71mm$, $2.43{\pm}0.68mm$, respectively. 2. In mixed dentition, it was shown that the width of keratinized gingiva on maxillary central incisors ($5.10{\pm}0.86$) was the widest(p<0.01), and that on maxillary lateral incisors, mandibular central and lateral incisors was $4.35{\pm}0.83mm$, $3.51{\pm}0.60mm$, $3.57{\pm}0.66mm$, respectively. 3. The width of anterior keratinized gingiva was significantly increased after the successive anterior teeth were completely erupted(p<0.001). The width of keratinized gingiva on maxillary central and lateral incisors, and mandibular central and lateral incisors was increased by $1.82{\pm}0.83mm$, $1.65{\pm}0.69mm$, $0.99{\pm}0.39mm$, and $1.14{\pm}0.98mm$, respectively. 4. There was no statistical significance in the difference of the width of anterior keratinized gingiva between male and female(p>0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.61-70
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• 2017

In this case, the impression surface of the existing denture was scanned and was inverted three-dimensionally to express the residual ridge form. Implant planning was performed on the superimposed data of the CT with the scanned image of the denture with radiopaque markers attached. At the day of surgery, customized abutments fabricated in accordance with the form of the gingival margin were linked with fixtures and temporary restorations were set. In the process of fabricating the final prosthesis after the osseointegration of implant fixture, the intraoral scan images at abutment level were merged with images of the abutments scanned and stored before implant surgery. By fabricating the final prosthesis with the abutments obtained by merging can increase the marginal fitness of the final prosthesis and simplify the clinical process.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.1
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• pp.79-87
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• 2021

The digital workflow of optical impressions by the intraoral scanner and CADCAM manufacture of dental prostheses is actively developing. The complex process of traditional impression taking, definite cast fabrication, wax pattern making, and casting has been shortened, and the number of patient's visits can also be reduced. Advances in intraoral scanner technology have increased the precision and accuracy of optical impression, and its indication is progressively widened toward the long span fixed dental prosthesis. This case report describes the long span implant case, and the operator fully utilized digital workflow such as computer-guided implant surgical template and CAD-CAM produced restoration after the digital impression. The provisional restoration and customized abutments were prepared with the optical impression taken on the same day of implant surgery. Moreover, the final prosthesis was fabricated with the digital scan while utilizing the same customized abutment from the provisional restoration. During the data acquisition step, stl data of customized abutments, previously scanned at the time of provisional restoration delivery, were imported and automatically aligned with digital impression data using an 'A.I. abutment matching algorithm' the intraoral scanner software. By using this algorithm, it was possible to obtain the subgingival margin without the gingival retraction or abutment removal. Using the digital intraoral scanner's advanced functions, the operator could shorten the total treatment time. So that both the patient and the clinician could experience convenient and effective treatment, and it was possible to manufacture a prosthesis with predictability.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.157-164
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• 2024

A variety of digital technologies are being used throughout the entire implant treatment process of diagnosis, surgery, impression, design, and fabrication of prostheses. In this case, using a digital surgical guide, sinus floor elevation was performed without complications, and the implants were placed in the planned position. After the healing period for osseointegration, CAD-CAM (Computer-aided design-Computer-aided manufacturing) customized abutments and provisional prostheses were delivered. While using the provisional prosthesis, occlusal change was observed. To transfer the intermaxillary relationship and abutment position that reflect occlusal change and axial displacement, double scanning and abutment-level digital impressions were taken. Abutment superimposition was used to capture the subgingival margin without gingival retraction. Then, the definitive prosthesis was designed and fabricated with digital system. We report a case applying digital system, to achieve the predictable result as well as the efficient treatment process from implant surgery to fabricating prosthesis in the posterior area.