• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.2
• /
• pp.280-289
• /
• 2004

Adequate polymerization is a crucial factor in obtaining optimal physical properties and clinical performance of resin composite restorative materials. The purpose of this study was to determine the effectiveness of shade and depth on dental composite resin polymerized with plasma arc curing unit employing FTIR and microhardness. From this experiment, the following results were obtained : 1. The light transmission and microhardness by mode 6 in plasma arc curing were similar to by 20 secs in halogen light curing. 2. The experimental groups of A1, A2, A3, A3.5 were not signifcant difference to light transmission and microhardness on surface and 2mm depth, but were significant difference on 3mm and 4mm depth. Especially light transmission and microhardness were small in darker shade and deeper thickness. 3. Compared with depth cure, uncured monomer amount increased at more than 2mm depth. 4. The light transmission by FTIR and polymerization by microhardness were significant corelation.

• The korean journal of orthodontics
• /
• v.34 no.5 s.106
• /
• pp.408-416
• /
• 2004

The purpose of this study was to investigate the preference of Vertical Lip-Chin Ratio (=Sn-Stm/Stm-Me', hereafter VLCR) in Koreans. The assessors consisted of 44 dentists (male 22, female 22) and 430 lay persons (male 303, female 127). The survey was performed using a questionnaire asking the order of preference. The profiles presented in the questionnaire were based on the profiles of two males and two females, each morphed according to the VLCRs of 1/1.8, 1/1.9, 1/2.0. 1/2.1, 1/2.2. The results were as follows: The difference between males and females. and the difference betwwen dentists and lay persons in the preference of VLCR were not statistically apparent. The most Preferred VLCR was 1/1.9, and the least preferred VLCR was 1/2.2, These results Indicate that the preferred VLCR is smaller than the previously reported VLCR ratios based on the cephalometric evaluation of samples with favorable facial esthetics.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.37 no.2
• /
• pp.73-80
• /
• 2021

Purpose: The purpose of this study is to compare the color stability of provisional restorative materials fabricated by subtractive and additive manufacturing. Materials and Methods: PMMA specimens by subtractive manufacturing and conventional method and bis-acryl specimens by additive manufacturing were fabricated each 20. After immersing specimens in the coffee solution and the wine solution, the color was measured as CIE Lab with a colorimeter weekly for 4 weeks. Color change was calculated and data were analyzed with one-way ANOVA and the Tukey multiple comparisons test (α = 0.05). Results: PMMA provisional prosthetic materials by subtractive manufacturing showed superior color stability compared to bis-acryl provisional prosthetic materials by additive manufacturing (P < 0.05), and showed similar color stability to the PMMA provisional prosthetic materials by conventional method (P > 0.05). Conclusion: It is recommended to fabricate provisional restorations by subtractive manufacturing in areas where esthetics is important, such as anterior teeth, and consideration of the color stability will be required when making provisional prosthetic using additive manufacturing.

• The Journal of Korean Academy of Prosthodontics
• /
• v.61 no.3
• /
• pp.245-256
• /
• 2023

When restoring with a dental digital system for implant-supported prosthesis, a double digital scanning technique is required: an intraoral scan of the three-dimensional implant location and intraoral scan after placement of temporary denture or provisional prosthesis. During the intraoral scan, the use of scan body as a stable landmark can improve the accuracy of digital impression and simplify laboratory process. In this case, a full-digital system was used to plan and fabricate a custom abutment, provisional prosthesis, and definitive prosthesis. After implant placement, the scan area of the intraoral scan body connected with implant and the intraoral scan body marked on the inside of temporary denture were superimposed. Out of the superimposed files, a custom abutment and provisional prosthesis were fabricated which match the vertical dimension of temporary denture, and definitive prosthesis was fabricated based on provisional prosthesis. We report this case because result has been functionally and esthetically satisfactory by using vertical dimension and central relation set during the fabrication of temporary denture to the definitive prosthesis.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.49 no.4
• /
• pp.414-427
• /
• 2022

This study aims to analyze the color distribution of maxillary permanent incisors in Korean pediatric patients and determine the effects of age and root developmental stage on tooth color. The L^*a^*b^* values of 404 sound and fully erupted maxillary incisors without dental caries, restorations, trauma history or discoloration from 101 Korean patients between ages 7 and 15, with a mean age 10.0 ± 1.5, were analyzed with a spectrophotometer. CIE L^*a^*b^* values were 84.01, 0.17, and 24.07 in maxillary central incisors, and 82.33, 0.31, and 25.99 in maxillary lateral incisors. L^* values of maxillary central incisors were higher, and b^* values of maxillary central incisors were lower than those of maxillary lateral incisors (p < 0.001). The color differences among the subregions exceeded the clinical perceptibility threshold in both of the maxillary central and lateral incisors. L^* value for children at age 10 and younger was 84.13 in maxillary central incisors and 84.04 in maxillary lateral incisors, and those of older patients were 80.62 and 80.56, respectively. L^* value of maxillary incisors of children at age 10 and younger was significantly higher than that of older patients. The root developmental stage did not affect tooth color. This study suggests that the color differences between maxillary central and lateral incisors and among the subregions of a tooth and the effects of age should be considered for aesthetic restorations of permanent incisors in pediatric patients.

• Restorative Dentistry and Endodontics
• /
• v.18 no.2
• /
• pp.413-422
• /
• 1993

The purpose of this study was to evaluate the adaptation of light cured glass ionomer cement and composite resin using all- etch technique to tooth structure. In this study, class V cavities were prepared on the buccal surfaces of 10 extracted human premolar teeth with cementum margin and teeth were randomly assigned 2 groups of 5 teeth each. The cavities of glass ionomer cement group were filled with the light cured glass ionomer cement(Fuji II LC) and the cavities of composite resin group were filled with the light cured composite resion(P - 50) using all- etch technique with All- Bond 2. The restored teeth were stored in 100 % relative humidity at $37^{\circ}C$ for 48 hours. And then, the roots of the teeth were removed with the tapered fissure bur and the remaining crowns were sectioned occlusogingivally through the center of restorations. Adaptation at tooth - restoration interface were assessed occlusally, gingivally, and axially by scanning electron microscope. The results were as follows : 1. The adaptation to enamel walls of composite resin restorations using All - Bond 2 showed better than glass ionomer restorations. 2. The adaptation to gingival and axial walls of glass ionomer restorations showed better than composite resin restorations using All - Bond 2. 3. In both groups, occlusal margins of restorations showed better adaptation than gingival margins of restorations.

• Restorative Dentistry and Endodontics
• /
• v.26 no.2
• /
• pp.127-133
• /
• 2001

There are several factors affecting the effectiveness of polymerization of the esthetic restorative materials. Among those factors, the initiator. camphoroquinone has the unique characteristic. of which the light sensitivity is very dependent on the wavelength of blue light. Camphoroquinone shows the most light absorption ability in the wavelength range of 470nm. So most of clinically used light curing systems adopt this phenomenon as their polymerization mechanism. The most popular way of light curing system is standard 40 second curing. But the problem of standard curing technique shows the rapid increase of resin viscosity followed by the acceleration of polymerization and the limited resin flow, resulted in reduction of the physicalproperty of restoration by retained stress. The object of this study was to verify the effects of narrow-banded wavelength on the microhardness of the esthetic restorative materials. a composite resin and a compomer, using filters which have peak wave length of 430nm, 450nm, 470nm, respectively. The results were as follows: 1. All the experimental groups showed lower hardness value than the control group. 2. In DyractAP, the hardness value by wavelength showed the same changing pattern on both upper and lower surfaces. 3. In DenFil, the hardness value by wavelength showed different changing pattern on upper and lower surfaces. 4. The hardness ratio showed similar pattern to the hardness variation of lower surface. but there was no significant difference between measurement in 10 minutes and 3 days later, besides the increase of hardness value.

• The Journal of Korea Assosiation for Disability and Oral Health
• /
• v.12 no.2
• /
• pp.66-71
• /
• 2016

Intellectual disability is accompanied by a high incidence of congenitally absent teeth and supernumerary teeth, and is observed more frequently than are disorders of location and order during delayed eruption, when accompanied by other symptoms. Furthermore, it is associated with a higher occurrence of dental anomalies such as conical teeth, microdontia, and amelogenesis imperfecta. As it is difficult to obtain adequate cooperation from patients with intellectual disabilities, physical restraint and conscious sedation using medication and general anesthesia can be considered. Reshaping of conical teeth with resin composite may be helpful to rehabilitate patients with oligodontia and a conical tooth shape. Diagnostic wax-up and a silicone matrix formed the basis for the successful reconstruction of the anterior teeth. This case describes the treatment of a patient with intellectual disability who had oligodontia and conical-shaped incisors. Under general anesthesia, the patient was treated using direct composite resin restoration.

• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.1
• /
• pp.29-37
• /
• 2011

Purpose: In cases when implant supported overdenture is made by using standard size implant, additional procedure such as bone surgery and bone grafting can be required. And it gives burden to doctor and patient in terms of cost. Therefore, it is necessary to find the implant therapy for the edentulous patients in making denture with accordable cost and simple procedure. Materials and methods: Edentulous patients with upper and lower dentures participated in this study. Before the operation, survey about patient's satisfaction to the existing dentures was carried out. Surgical procedures included four small diameter implants installation anterior area and immediate loading. One and three month after the procedure, the same survey about patient's satisfaction was carried out, and radiography was taken. Results: We are doing research to the nine patients. Survival rate is 97.2 percent. The comparison of patient's satisfaction before and after surgery is performed based on oral health impact profile 49. We analyze mainly with masticatory discomfort, retention, aesthetics, social problem, psychological discomfort problems. As a result, satisfaction level is increased at all factors. Retention is the most increased satisfactory factor followed by mastication difficulty, pronunciation, psychological discomfort, social discomfort, aesthetics in order. Marginal bone loss is 0.21 mm at 12 weeks after implant placement. Conclusion: This research reveals that the denture supported by mini dental implant increases patient's satisfaction. This study will be continued with more patients for a long time and we are scheduled for taking additional radiography to check whether peri-implant bone resorption occurs or not.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.2
• /
• pp.190-201
• /
• 2004

The aim of this study was to evaluate the resistance to degradation and to compare the wear resistance characteristics of four esthetic restorative materials in an alkaline solution. The brands studied were Charmfil, Charmfil flow(composite resin), Compoglass F and PrimaFlow(compomer). The results were as follows: 1. The mass loss were not significantly different among the materials(p>0.05). 2. The sequence of the degree of degradation layer depth was in descending order by Compoglass F, PrimaFlow, Charmfil, and Charmfil flow. There were significant differences between Compoglass F and the others(p<0.05). 3. The sequence of the Si loss was in descending order by Charmfil flow, Charmfil, PrimaFlow, and Compoglass F. There were significant differences among these materials(p<0.05). 4. When observed with SEM, destruction of bonding between matrix and filler was observed and when observed with CLSM, the depth of degradation layer of specimen surface was observed. 5. The sequence of maximum wear depth was in descending order by Comfoglass, PrimaFlow Charmal, and Charmfil flow. There were significant differences among these materials(p<0.05). 6. The correlation coefficient between Si loss and degradation layer depth (r=0.602, p<0.05) Vicker's hardness number and maximum wear depth (r=0.501, p<0.05) were relatively high. These results indicate that wear and hydrolytic degradation may be considered to be evaluation factors of composite resins and compomers.