• Journal of Technologic Dentistry
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• v.41 no.1
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• pp.1-7
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• 2019

Purpose: The objectives of this study was to evaluate clinical adaptation of dental prostheses printed by 3 dimensional(3D) printing technology. Methods: Ten study models were prepared. Ten specimens of experimental group were printed by 3D printing(3DP group). As a control group, 10 specimens were fabricated by casting method on the same models. Marginal gaps of all specimens were measured to evaluate clinical adaptation. Marginal adaptations were measured using silicone replica technique and measured at 8 sites per specimen. Wilcoxon's signed-ranks test was used for statistical analysis(${\alpha}=0.05$). Results: Means of marginal adaptations were $95.1{\mu}m$ for 3DP group and $75.9{\mu}m$ for CAST group(p < 0.000). Conclusion : However, the mean of the 3DP group was within the clinical tolerance suggested by the previous researchers. Based on this, dental prosthesis fabricated by 3D printing technology is considered to be clinically acceptable.

• Journal of Technologic Dentistry
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• v.38 no.3
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• pp.185-191
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• 2016

Purpose: The purpose of this study were to evaluate the quality of dental prostheses printed by 3-dimensional printing system. Methods: Mater model was prepared and ten study models were fabricated. Ten single crowns were printed by 3D-printing system(Resin group) and another ten single crowns using casting method were manufactured(Metal group). The marginal adaptation of single crowns were measured using by silicone replica technique. Silicone replicas were sectioned four times. The marginal adaptations were evaluated using by digital microscope. Statistical analyses were performed with Mann-Whitney test(${\alpha}=0.05$). Results: $Mean{\pm}standard$ deviations of all marginal adaptations were $92.1(20.0){\mu}m$ for Metal group and $69.7(12.3){\mu}m$ for Resin group. Two groups were no statistically significant differences(p>0.05). Conclusion: Marginal adaptation of single crowns printed by 3D-printing system were ranged within the clinical recommendation.

• Journal of Technologic Dentistry
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• v.38 no.4
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• pp.305-311
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• 2016

Purpose: The purpose of this study were to analysis of marginal adaptation of metal cores fabricated by selective laser sintering. Methods: Main model was prepared and ten stone models were fabricated. Ten single metal cores were fabricated by selective laser sintering(SLS group) and another ten single metal cores using lost wax technique and casting method were manufactured(CAST group). The marginal adaptation of metal cores were analysis using by the silicone replica technique. Silicone replicas were sectioned two times. The marginal adaptations were measured using by digital microscope. Statistical analyses was performed with independent t-test(${\bullet}{\cdot}=0.05$). Results: Means of marginal adaptations were 90.3 ${\ss}{\uparrow}$ for SLS group and 65.1 ${\ss}{\uparrow}$ for CAST group. Two groups were statistically significant differences (p < 0.05). Conclusion: Marginal adaptation of metal cores fabricated by selective laser sintering were ranged within the clinical recommendation.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.158-168
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• 2016

This article is to review various methods used to investigate internal and marginal adaptation of fixed dental prostheses, and to summarize a merit, worth, and limitation of each method, using some results of previous studies. The methods of measuring internal and marginal gap are divided into two categories in this study; in vivo and in vitro. In vivo methods are clinical evaluations, including exploration, radiography, and impression technique. In vitro methods are laboratory evaluations such as direct view, cross-sectioning, and silicone replica technique using microscope. Measuring by micro computed tomography (CT) or profilometer is also in vitro methods. In recent years, the development of scanning systems is able to analyze 3-dimensional internal and marginal space in detail. As measuring and analyzing technology become more advanced, the ability to thoroughly examine crown adaptation is becoming both simpler and more efficient.

• The Journal of Advanced Prosthodontics
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• v.3 no.2
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• pp.69-75
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• 2011

This study assessed the effect of preparation design on marginal adaptation and also compared the sensitivity and specificity of clinical evaluation techniques for marginal accuracy of cast restorations to stereomicroscopy. MATERIALS AND METHODS. Three Ivorine molar teeth of different designs were prepared. (A)-A complete crown preparation with buccal shoulder and beveled finish line. (B)-A complete crown preparation with chamfer finish line. (C)-A three-quarter crown preparation with proximal boxes and beveled finish line. Twenty four castings were prepared with eight castings for each design respectively. Each casting underwent examination with an explorer, disclosing media, and a stereomicroscope. Stereomicroscopy at a value less than or equal to 30 microns was used as a gold standard to evaluate the significance of different designs on marginal adaptation. Chi-square tests of independence and Kruskal-Wallis were used to evaluate the effect of preparation design and compare the agreement between examination methods for detection of marginal gap size of greater than or equal to 30 microns (${\alpha}$=.05). Sensitivity and specificity for explorer and disclosing media as compared to stereomicroscope was calculated using statistical formula given by Park. RESULTS. The preparation design did not significantly affect overall marginal adaptation. Examination by explorer and disclosing media at $30 \;{mu}m$ revealed 39% and 10.06% sensitivity and 91% and 82% specificity respectively. CONCLUSION. Preparation designs examined in this study did not significantly affect the marginal adaptation of the castings. Commonly used clinical evaluation techniques using explorer and disclosing media appeared to be inadequate for assessment of marginal accuracy.

• The Journal of Advanced Prosthodontics
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• v.12 no.6
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• pp.344-350
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• 2020

PURPOSE. Recently introduced hybrid and reinforced glass ceramic computer-aided design/computer-aided manufacturing (CAD/CAM) materials have been used for full-coverage restorations. However; the effect of adjustment and type of materials on internal and marginal adaptation are unknown. This study aimed to evaluate and compare the marginal and internal adaptations of crowns made of three different CAD/CAM materials before and after adjustment. MATERIALS AND METHODS. One acrylic resin maxillary first molar was prepared and served as the master die. Thirty-six restorations were fabricated using CAD/CAM system (CEREC Omnicam, MCXL) with three materials including lithium disilicate (IPS e.max CAD), zirconia-reinforced lithium silicate (Suprinity), and hybrid ceramic (Enamic). Internal and marginal adaptations were evaluated with the reference point matching technique before and after adjustment. The data were analyzed using mixed ANOVA considering α=.05 as the significance level. RESULTS. The effect of adjustment and its interaction with the restoration material were significant for marginal, absolute marginal, and occlusal discrepancies (P<.05). Before adjustment, Suprinity had lower marginal discrepancies than IPS e.max CAD (P=.18) and Enamic (P=.021); though no significant differences existed after adjustment. CONCLUSION. Within the limitations of this study, crowns fabricated from IPS e.max CAD and Suprinity resulted in slightly better adaptation compared with Enamic crowns before adjustment. However, marginal, axial, and occlusal discrepancies were similar among all materials after the adjustment.

• The Journal of Advanced Prosthodontics
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• v.13 no.6
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• pp.373-384
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• 2021

PURPOSE. This study aimed to compare the marginal and internal fit of 3-unit monolithic zirconia restorations that were designed by using the data obtained with the aid of intraoral and laboratory scanners. MATERIALS AND METHODS. For the fabrication of 3-unit monolithic zirconia restorations using impressions taken from the maxillary master cast, plaster cast was created and scanned in laboratory scanners (InEos X5 and D900L). The main cast was also scanned with different intraoral scanners (Omnicam [OMNI], Primescan [PS], Trios 3 [T3], Trios 4 [T4]) (n = 12 per group). Zirconia fixed partial dentures were virtually designed, produced from presintered block, and subsequently sintered. Marginal and internal discrepancy values (in ㎛) were measured by using silicone replica method under stereomicroscope. Data were statistically analyzed by using 1-way ANOVA and Kruskal Wallis tests (P<.05). RESULTS. In terms of marginal adaptation, the measurements on the canine tooth indicated better performance with intraoral scanners than those in laboratory scanners, but there was no difference among intraoral scanners (P<.05). In the premolar tooth, PS had the lowest marginal (86.9 ± 19.2 ㎛) and axial (92.4 ± 14.8 ㎛), and T4 had the lowest axio-occlusal (89.4 ± 15.6 ㎛) and occlusal (89.1 ± 13.9 ㎛) discrepancy value. In both canine and premolar teeth, the D900L was found to be the most marginally and internally inconsistent scanner. CONCLUSION. Within the limits of the study, marginal and internal discrepancy values were generally lower in intraoral scanners than in laboratory scanners. Marginal discrepancy values of scanners were clinically acceptable (< 120 ㎛), except D900L.

• Journal of Technologic Dentistry
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• v.42 no.3
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• pp.228-233
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• 2020

Purpose: This study aimed to assess and compare the marginal fit of ceramic-based hybrid resin restoration (HYB) and zirconia restoration (ZIR) for dental computer-aided design/computer-aided manufacturing systems. Methods: A stainless steel master model was produced. The impression was first made with silicone, and then stone working models were produced. A total of twenty restorations were fabricated with two different materials: ZIR and HYB. The silicone film thickness of the marginal gap was measured using a digital microscope; digital photos were taken at a magnification of ×160, and then analyzed using a measurement software. The values of the result were evaluated with the independent-sample t-test (α=0.05). All statistical analyses were performed with a statistical software. Results: The mean values for the marginal gap was 37.14±2.96 ㎛ for HYB, compared with 40.37±5.26 ㎛ for ZIR. No significant difference was found between ZIR and HYB (p=0.107). Conclusion: As a result, the marginal fit of the restoration fabricated using the hybrid resin was better than that of the restoration fabricated using zirconia. Also, the marginal fit of all groups was below the clinical acceptable range of 120 ㎛. Thus, HYB for dental CAD/CAM system in this study is expected to be suitable for clinical use in dentistry.

• Journal of Technologic Dentistry
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• v.42 no.3
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• pp.197-201
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• 2020

Purpose: This study aimed to assess the quality of dental prostheses printed by digital light-processing (DLP) technology. Methods: Ten experimental models were prepared. The ten specimens that were printed by DLP technology constituted the DLP group. The ten specimens that were produced in the same model by the casting method constituted the control group. The marginal gaps of the 20 specimens produced were measured. These gaps were measured by a silicon replica technique at two abutments of the specimen. Therefore, 20 marginal gaps were measured in each group. An independent sample t-test was performed to compare the marginal gaps measured in the two groups (α=0.05). Results: According to the results of the measurement, there was a significant difference between the mean marginal gap of the control group (78.8 ㎛) and that of the DLP group (91.5 ㎛), p<0.001. Conclusion: Although the mean marginal gaps of dental fixed prostheses produced by the DLP method was higher than the mean marginal gap of those produced by the casting method, it was considered to be within the clinical threshold value suggested by some previous studies.

• Journal of Technologic Dentistry
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• v.44 no.4
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• pp.126-131
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• 2022

Purpose: The purpose of this study is to evaluate the quality of dental fixed prostheses fabricated by 3DP (three-dimensional printing). Methods: Ten main models were prepared for the study. Ten specimens were printed by 3DP (3DP group). Ten specimens were fabricated by the lost wax technique and casting method to complete the control group (LWC group). The marginal fit was measured for 20 specimens. The measurement of marginal fit was performed using the silicon replica technique. Finally, the marginal fit of 10 specimens from each group was calculated. An independent sample t-test was run to see if the calculated averages for the two groups were mutually significant (α=0.05). Results: According to the experimental results, the mean marginal fit of the 3DP group was 71.9 ㎛, and the LWC group was 55.3 ㎛. The means of the two groups were found to be significantly different (p<0.001) in the results of the independent sample t-test. Conclusion: The marginal fit of fixed dental prostheses produced by 3DP technology was examined with values greater than those fabricated by traditional technology. However, as it appeared to be a value within the range of clinically acceptable range recommended by numerous studies, it was determined that clinical application would be feasible.