• The Journal of Korean Academy of Prosthodontics
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• v.56 no.3
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• pp.199-205
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• 2018

Purpose: This study evaluated the effect of nonthermal plasma treatment on the bond strength of autopolymerizing relining resin to the injection molded thermoplastic denture base resins (TDBRs) with different surface treatments. Materials and methods: Acrylic Resin (Acrytone), Polyester (Estheshot-Bright), Polyamide (Valplast) and Polypropylene (Weldenz) were subjected to various surface treatments: No treatment, Nonthermal plasma, Sandblasting, Sandblasting and nonthermal plasma. Specimens were bonded using an autopolymerizing relining resin. Shear bond strength was tested using universal testing machine with crosshead speed of 1 mm/min. Statistical analysis by two-way analysis of variance with Tukey's test post hoc was used. Results: Acrytone showed significantly higher shear bond strength value among other TDBR group while Weldenz had the lowest. The sandblasting and nonthermal plasma condition had significantly higher shear bond strength value in all of the resin groups (P < .05). Conclusion: The use of nonthermal plasma treatment showed limited effect on the shear bond strength between TDBRs and relining resin, and combination of nonthermal plasma and sandblasting improved the shear bond strength between TDBR and reline material.

• 대한치과보철학회:학술대회논문집
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• 2001.11a
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• pp.41-41
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• 2001

• The Journal of Advanced Prosthodontics
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• v.15 no.2
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• pp.80-92
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• 2023

PURPOSE. This study incorporated the nanomaterial, nanostructured silver vanadate decorated with silver nanoparticles (AgVO₃), into heat-cured resin (HT) at concentrations of 2.5%, 5%, and 10% and compared the adhesion of multispecies biofilms, surface characteristics, and mechanical properties with conventional heat-cured (HT 0%) and printed resins. MATERIALS AND METHODS. AgVO₃ was incorporated in mass into HT powder. A denture base resin was used to obtain printed samples. Adhesion of a multispecies biofilm of Candida albicans, Candida glabrata, and Streptococcus mutans was evaluated by colony-forming units per milliliter (CFU/mL) and metabolic activity. Wettability, roughness, and scanning electron microscopy (SEM) were used to assess the physical characteristics of the surface. The mechanical properties of flexural strength and elastic modulus were tested. RESULTS. HT 10%-AgVO₃ showed efficacy against S. mutans; however, it favored C. albicans CFU/mL (P < .05). The printed resin showed a higher metabolically active biofilm than HT 0% (P < .05). There was no difference in wettability or roughness between groups (P > .05). Irregularities on the printed resin surface and pores in HT 5%-AgVO₃ were observed by SEM. HT 0% showed the highest flexural strength, and the resins incorporated with AgVO₃ had the highest elastic modulus (P < .05). CONCLUSION. The incorporation of 10% AgVO₃ into heat-cured resin provided antimicrobial activity against S. mutans in a multispecies biofilm did not affect the roughness or wettability but reduced flexural strength and increased elastic modulus. Printed resin showed higher irregularity, an active biofilm, and lower flexural strength and elastic modulus than heat-cured resin.

• Journal of Technologic Dentistry
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• v.43 no.3
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• pp.84-92
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• 2021

Purpose: The purpose of this study was to compare the dimension safety evaluation between a general ultrasonic cleaner and an ultrasonic cleaner equipped with UV-C (ultraviolet-C). Methods: An edentulous model was prepared. A denture base and an occlusal rim were fabricated, and scanning was performed. After scanning, a denture base and full arch artificial teeth were designed. The full arch artificial teeth were printed using a three-dimensional printer (n=10). The residual resin was washed with alcohol and then scanned (reference data). The printed specimens were classified and cleaned using a general ultrasonic cleaner (GU group) and an ultrasonic cleaner equipped with UV-C (UC group). After each washing, a rescan was performed (scan data). Reference data and scan data were superimposed using overlapping software. Data were statistically analyzed using the Mann-Whitney test (α=0.05). Results: In the deviation values of full arch artificial teeth, the GU group showed a high deviation of 18.02 ㎛ and the UC group showed a low deviation of 15.02 ㎛. The two groups demonstrated a statistically significant difference (p<0.05). Conclusion: Full arch artificial teeth prepared using photopolymerized resin were deformed according to the temperature of water generated in the ultrasonic cleaner. It is judged that there is no deformation according to the UV-C ultrasonic cleaner.

• Journal of Technologic Dentistry
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• v.12 no.1
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• pp.113-119
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• 1990

The purpose of this study was to investigate the effect of surface tretment on strength of denture repair as influenced by repair resin. Specimens were fabricated from VERTEX heat cured resin. Rectangular specimens($60\times10\times3mm$) were prepared according to the manufacturer's instruction for mixing and packing the resin into molds. Two methods of surface treatment were used and two methods of repair were also tested. The transverse strength of the resin was measured before repair and after repair by AUTOGRAPH testing machine. Six specimens of each category were prepared for testing for a total of 24 specimens. The mean value of the percent of recovery was calculated from the percent of recovery for six specimens. The results were as follows : 1. The mean value of the percent of recovery of each category makes a significant difference statistically one another(p<0.01), and "C" category, chloroform solvent-heat cured resin, has a better effect on repair srength than any other. 2. When no chloroform is used to treat the fractured surface there is no significant difference between the mean values of the percent of recovery influenced by the self curing resin and heat cured resin. But, when chloroform is used there is a significant difference between the two repair resins(p<0.01). 3. When self curing resin repair is used there is no significant difference between repair with and without the surface treatment of chloroform. But, when heat cured resin repair is used the use of chloroform treatment become significant statistically (p<0.01).

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.361-366
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• 2018

PURPOSE. The aim of this study was to evaluate the effects of relining materials on the flexural strength of relined thermoplastic denture base resins (TDBRs). MATERIALS AND METHODS. For shear bond strength testing, 120 specimens were fabricated using four TDBRs (EstheShot-Bright, Acrytone, Valplast, Weldenz) that were bonded with three autopolymerizing denture relining resins (ADRRs: Vertex Self-Curing, Tokuyama Rebase, Ufi Gel Hard) with a bond area of 6.0 mm in diameter and were assigned to each group (n=10). For flexural strength testing, 120 specimens measuring $64.0{\times}10.0{\times}3.3mm$ (ISO-1567:1999) were fabricated using four TDBRs and three ADRRs and were assigned to each group (n=10). The thickness of the specimens measured 2.0 mm of TDBR and 1.3 mm of ADRR. Forty specimens using four TDBRs and 30 specimens using ADRRs served as the control. All specimens were tested on a universal testing machine. For statistical analysis, Analysis of variance (ANOVA) with Tukey's test as post hoc and Spearman's correlation coefficient analysis (P=.05) were performed. RESULTS. Acry-Tone showed the highest shear bond strength, while Weldenz demonstrated the lowest bond strength between TDBR and ADRRs compared to other groups. EstheShot-Bright exhibited the highest flexural strength, while Weldenz showed the lowest flexural strength. Relined EstheShot-Bright demonstrated the highest flexural strength and relined Weldenz exhibited the lowest flexural strength (P<.05). Flexural strength of TDBRs (P=.001) and shear bond strength (P=.013) exhibited a positive correlation with the flexural strength of relined TDBRs. CONCLUSION. The flexural strength of relined TDBRs was affected by the flexural strength of the original denture base resins and bond strength between denture base resins and relining materials.

• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.167-171
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• 2016

PURPOSE. This study inspects the effect of incorporating halloysite nanotubes (HNTs) into polymethyl methacrylate (PMMA) resin on its flexural strength, hardness, and Young's modulus. MATERIALS AND METHODS. Four groups of acrylic resin powder were prepared. One group without HNTs was used as a control group and the other three groups contained 0.3, 0.6 and 0.9 wt% HNTs. For each one, flexural strength, Young's modulus and hardness values were measured. One-way ANOVA and Tukey's test were used for comparison (P<.05). RESULTS. At lower concentration (0.3 wt%) of HNT, there was a significant increase of hardness values but no significant increase in both flexural strength and Young's modulus values of PMMA resin. In contrast, at higher concentration (0.6 and 0.9 wt%), there was a significant decrease in hardness values but no significant decrease in flexural strength and Young's modulus values compared to those of the control group. CONCLUSION. Addition of lower concentration of halloysite nanotubes to denture base materials could improve some of their mechanical properties. Improving the mechanical properties of acrylic resin base material could increase the patient satisfaction.

• The Journal of Advanced Prosthodontics
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• v.14 no.1
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• pp.45-55
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• 2022

PURPOSE. This in vitro study investigates the effect of different post-rinsing times and methods on the trueness and precision of denture base resin manufactured through stereolithography. MATERIALS AND METHODS. Ninety clear photopolymer resin specimens were fabricated and divided into nine groups (n = 10) based on rinsing times and methods. All specimens were rinsed with 99% isopropanol alcohol for 5, 10, and 15 min using three methods-automated, ultrasonic cleaning, and hand washing. The specimens were polymerized for 30 min at 40℃. For trueness, the scanned intaglio surface of each SLA denture base was superimposed on the original standard tessellation language (STL) file using best-fit alignment (n = 10). For precision, the scanned intaglio surface of the STL file in each specimen group was superimposed across each specimen (n = 45). The root mean square error (RMSE) was measured, and the data were analyzed statistically through one-way ANOVA and Tukey test (α < .05). RESULTS. The 10-min automated group exhibited the lowest RMSE. For trueness, this was significantly different from specimens in the 5-min hand-washed group (P < .05). For precision, this was significantly different from those of other groups (P < .05), except for the 15-min automated and 15-min ultrasonic groups. The color map results indicated that the 10-min automated method exhibited the most uniform distribution of the intaglio surface adaptation. CONCLUSION. The optimal postprocessing rinsing times and methods for achieving clear photopolymer resin were found to be the automated method with rinsing times of 10 and 15 min, and the ultrasonic method with a rinsing time of 15 min.

• Journal of Korean society of Dental Hygiene
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• v.21 no.6
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• pp.703-710
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• 2021

Objectives: The purpose of this study was to confirm the influence of commercially available carbonated water on denture resin by confirming the changes in the denture surface and adhesion of bacteria. Methods: Carbonated water available in the domestic market was used on specimens made of prosthetic resins. The top four products with respect to sales performance was deposited for 30 min, 24 h, and 48 h over the study groups and over one control group. The surface roughness was measured. Candida albicans was inoculated and cultured over these dentures at 37℃ on the study groups of 1 h, 24 h, and 48 h, and the number of colonies formed was measured. Results: As a result of comparing the surface roughness between groups by immersion time, the difference between groups was confirmed at 48 hours. The Trevi group showed a larger Rz than the Samdasoo group. As a result of comparing the surface roughness by time in each group, statistical significance was shown in the Ra value of the Seagram and the Rz value of the Chojung sparkling water (p<0.05). The Ra value of the Seagram was higher for 48 h than for 30 min, and the Rz value of the Chojung sparkling water was higher at 48 h than at 30 min (p<0.05). Candida albicans concentration increased over the course of immersion. Conclusions: It was confirmed that longer the specimen of the denture resin was immersed in carbonated water, more the surface roughness was affected and higher the number of attached bacteria.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.87-93
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• 2010

Purpose: The purpose of this study was to compare the retention of the two denture adhesives with a silicone edentulous model and a resin denture base in vitro study. Material and methods: The experimental groups were used two denture adhesives and classified into 5 subgroups each. Subgroups were divided by the number of times the saliva sprayed. The control group was used synthetic saliva only. Dislodging tensile strengths were applied to the resin denture base using Instron in 3 directions ; vertical, lateral, and anterior-posterior. Results: The retention of two denture adhesives was increased significantly than saliva alone (P <.05). In each denture adhesives, the retention of saliva sprayed first was decreased than denture adhesive alone, but it didn't have significant differences. Whenever saliva sprayed repeated, the retention was decreased significantly than saliva sprayed first (P <.05). In each denture adhesives, vertical retentive force was highest than lateral and anterior-posterior retentive forces, and anterior-posterior retentive force was higher than lateral retentive force. This results were significantly different (P < .05). Significant differences of the retentive ability among two denture adhesives were not observed. Conclusion: From the results, use of the denture adhesives resulted in improved retentive ability of denture. Especially retentive force was highest in vertical direction.