PURPOSE: The aims of the study were to evaluate the fracture load of zirconia core material after dipping in coloring liquid at different time intervals and to compare the color of dipped blocks with that of prefabricated shaded blocks. MATERIALS AND METHODS: 3-unit bridge frameworks were designed digitally. Sixty frameworks were fabricated using uncolored zirconia blocks by CAD/CAM and divided into 4 groups randomly (n = 15). Group 2 (G2) was subjected to coloring liquids for 2 minutes, Group 4 (G4) for 4 minutes, and Group 6 (G6) for 6 minutes. CFS group was not subjected to any coloring procedure. After coloring, color differences between the test groups and a prefabricated shaded zirconia group (CPZ, n = 15) were evaluated by using a spectrophotometer. Fracture test was conducted immediately after shade evaluation with a Testometric test device at a cross-head speed of 1 mm/sec. Statistical analysis for evaluating color and fracture load was performed by using one way ANOVA followed by Tukey HSD test (P ≤ .05). Weibull analysis was conducted for distribution of fracture load. RESULTS: There was no difference in terms of fracture load and color between CFS (1176.681 N) and G2 (985.638 N) group and between CPZ (81.340) and G2 (81.140) group, respectively. Fracture load values of G4 (779.340 N) and G6 (935.491 N) groups were statistically significantly lower than that of CFS group (P ≤ .005). The color values of G4 (79.340) and G6 (79.673) groups were statistically different than that of CPZ group (P ≤ .005). CONCLUSION: Prolonged immersion of zirconia in coloring liquid not only negatively affected the fracture load of the zirconia being tested in the current study but also deteriorated the desired shade of the restoration.
Ceramics* ; Immersion

The purpose of this study was to evaluate the effect of oral environment on the strength of resin bracket wings by comparing fracture mode according to water immersion and thermocycling. Seventy-five resin brackets(Spirit MB, Ormco, California) were divided into three groups and treated for six months as follows; (1) untreated, (2) water immersion in distilled water at 37degrees C, (3) water immersion in distilled water at 37degrees C with total 2,100 times of thermocyeling taken 350 times each month. Fracture mode of the wing was tested on universal testing machine. In addition to resin brackets, 25 metal brackets were used as controls. Through the statistical analyses, following results were obtained. 1. Resin bracket wings showed significantly lower fracture strength than metal brackets(p<0.001). 2. Water immersion and water immersion with thermocycling groups showed significantly lower fracture strength than open air condition group(p<0.001). 3. Water immersion with thermocycling group showed significantly lower fracture strength than water immersion group(p<0.001). The above results sugg est that the mechanical property of resin bracket wing may be influenced by oral environment and further research is needed to improve the strength of the wing in the resin bracket.
Immersion* ; Water*

The aim of this study was to evaluate the color stability of 4-methacryloxyethyl trimellitate anhydride (4-META) / methyl methacrylate (MMA) & tri-n-butylborane (TBB) resin with different powder-liquid (P/L) ratios and powder colors after immersion in coffee. Experimental groups (Bondfill SB) were classified by the P/L ratio (0.8:1 / 1:1 / 1.2:1, weight [wt] %) and color of the powder (light / medium). Light-cured resin composite (Filtek Z350 XT flowable) was used as a control group. Each disk-shaped specimen of 7 groups (n = 8 for color difference, n = 10 for translucency parameter [TP]) was immersed in a staining solution of coffee for 4 weeks. The color of the specimen was measured at the time of baseline, 1 day, 1 week, 2 weeks, 3 weeks, and 4 weeks with a spectrophotometer. The color difference (ΔE) and changes in translucency parameter (ΔTP) were statistically analyzed by one-way analysis of variance (ANOVA), followed by Tukey's post-hoc test. Independent t-test was applied to evaluate the effect on the colors of the powder (α = 0.05). The values of color difference (ΔE) of the experimental groups were within the clinically acceptable threshold (ΔE < 3.3), whereas control group showed values over 3.3 after 1 week of immersion. The values of TP ranged from 9.58 to 13.28. The differences of TP (ΔTP) between baseline and 4 weeks were less than 1.0, except in the control group. Conclusively, self-cured resin composite showed excellent color stability in coffee for the period of this study regardless of different P/L ratios and powder colors.
Coffee ; Immersion

The purpose of this study was to evalute the effect of immersion disinfection on the dimensional stability of rubber impression materials. The metallic master model was made in order to simulate the intraoral arch form. Impressions were made from four impression materials (Exaflex, Extrude, Reprosil, Impregum-F) and immersed in three disinfectant solutions (Wydex, Vi-Pon, Potadine). Casts from the impressions were measured according to the interpreparation distance. The A-B and The B-D abutment distance were compared with the control group and disinfected groups. The results were as follows; 1. The measurements of the stone cast increased relative to the master model and there was a significant difference (P<0.05). 2. The relative dimensional change of the stone cast as compared with master model ranged from 0.10% to 0.56% in the A-B distance and ranged from 0.04% to 0.27% in the B-D distance. 3. The dimensional change of the disinfected groups as compared with the control group was significantly different in the three impression materials except for Impregum-F (P<0.05). 4. The relative dimensional change of the disinfected groups compared with the control group ranged from 0% to 0.20% in the A-B distance and ranged from -0.09% to 0.11% in the B-D distance. These results suggest that immersion disinfection of rubber impression materials by chemical disinfectants causes very small dimensional change and the change is clinically acceptable for prothesis fabrication
Disinfectants ; Disinfection* ; Immersion* ; Rubber*

STATEMENT OF PROBLEM: Because dental impression can be a cross-infection source, disinfection, such as immersion disinfection is nessecary. However, the disinfection process may change the volume of the impression cast. PURPOSE: The purpose of this study is to find out the effects on dimensional change of different storage times and methods, of agar-alginate impression when immersed in a 5% idophor disinfectant. MATERIAL AND METHODS: An agar-alginate impression was made from a mandible model and then was disinfected and stored according the experimental conditions and a stone model was produced. Measurements were taken between reference points on the original mandible model and they were compared to measurements taken between reference points on the stone model. The study was divided into 4 groups. In group 1, the impression was stored in a 100% humidor for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 12 hours and 24 hours and stone models were made at each time. In group 2, the impression was immersed in 5% idophor disinfectant and then stored in a 100% humidor for the same length of times as group 1, and stone models were made at each time. In group 3, the impression was stored in extend-A-pourR, a special storage solution for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 6 hours, 12 hours, 24 hours 3 days, and 7 days and stone models were made at each time. In group 4, the impression was immersed in 5% idophor disinfectant and then stored in stored in extend-A-pourR, a special storage solution for the same length of times as group 3, and stone models were made at each time. 5 impressions and stone models were made at each time to make a total of 180. The Student-t test (P < .05) was used to do a statistical analysis of the measurements of the mandible model and stone models. The repeated-measure 2-way analysis of variance (P < .05) was used to do a statistical analysis of the difference in the 4 groups. RESULTS: The percent liner dimensional change was from 0.25+/-0.03% (group 1, 30 minutes) to 0.34+/-0.06% (group 4, 7 days). No significant change was noticed between the 4 groups. CONCLUSION: According to the above study, in both methods, least dimensional change was recorded when the storage times were short and in both methods, immersion in 5% idophor disinfectant did not effect dimensional change in the agar-alginate impression.
Disinfection* ; Immersion ; Mandible

The aim of this study was to evaluate the color stability of bulk-fill and conventional resin composites with respect to different storage media and thickness of composites.Filtek™ Z250 and Filtek™ Z350XT were evaluated as conventional resin composites. Filtek™ Bulk-fill Posterior Restorative and Tetric® N-Ceram Bulk Fill were evaluated as bulk-fill resin composites.CIE L*a*b* values of baseline were measured after 24 hours of storage in distilled water, and each resin composite group was divided into three subgroups and stored in distilled water, red wine, and coffee media respectively. Again after 1, 7 and 28 days of immersion, color changes (ΔE*) were calculated using the CIE L*a*b* values.The greatest ΔE* was observed in red wine for all resin composites, and the mean color changes were ranked in the increasing order of distilled water, coffee, red wine. Filtek™ Z350XT exhibited the greatest color change in all media, followed by Filtek™ Bulk-fill Posterior Restorative. Filtek™ Z250 and Tetric® N-Ceram Bulk Fill followed with similar mean color change values. According to the 2 different thicknesses of 2 mm and 4 mm of bulk-fill resin composites, there was no thickness-related difference on color changes.
Coffee ; Immersion ; Water ; Wine

OBJECTIVES: This study investigated the effect of red and white wine on color changes of nanofilled and nanohybrid resin composite. MATERIALS AND METHODS: Sixty specimens of each resin composite were prepared. Baseline data color values were recorded using a spectrophotometer. Three groups of discs (n = 20) were then alternately immersed in red, white wine, and deionized water (as a control) for twenty five minutes and artificial saliva for five minutes for four cycles. Specimens were then stored in artificial saliva for twenty two hours. This process was repeated for five days following immersion in artificial saliva for two days. Subsequently, the process was repeated again. Data were analyzed by two-way repeated ANOVA, one-way ANOVA, and Tukey's HSD. RESULTS: Red wine caused significantly higher color change (ΔE* > 3.3) than did white wine and deionized water (p < 0.05). Nanohybrid resin composites had significantly more color changes than nanofilled resin composite (p < 0.05). CONCLUSIONS: The effect of red and white wine on the color changes of resin composite restorative materials depended upon the physical and chemical composition of the restorative materials and the types of wine.
Immersion ; Saliva, Artificial ; Water ; Wine*

The purpose of this study was to evaluate the color changes of composite resin polymerized with three type of light curing units. Composite resin (Z100, shade A2) were applied in a cylindrical metal mold(2 mm thick, 7 mm diameter). Twenty specimens according to light curing units were made. Group1: the specimens were polymerized with Apollo 95E for 3seconds(1370 mW/cm2). Group2: the specimens were polymerized with XL 3000 for 40seconds(480 mW/cm2). Group3: the specimens were polymerized with Spectrum 800 for 10 seconds(250 mW/cm2) and 30 seconds(700 mW/cm2). The microhardness values(VHN) of upper and lower surfaces specimens after light polymerization were measured for the degree of polymerization. All specimens were stored in distilled water at 60degrees C for 30 days. The color characteristics(L*, a*, b*) of the specimens before and after immersion were measured by spectrophotometer and the total color difference (DeltaE*) was computed. The results obtained were as follows: 1. The microhardness values of Group I showed significantly lower than those of Group II and III(p<0.05). 2. In all groups the DeltaE* values presented below 2.0. 3. Group I showed the highest DeltaE* values followed order from highest to lowest by Group II and III (p<0.05).
Immersion ; Light ; Polymerization ; Polymers ; Water

Barangay Tinajero is one of the most depressed barangays (barrios) among the 21 barangays of Bacolor, Pampanga. Two UPCM (University of the Philippines, College of Medicine) Class 2012 Regionalization Program (RP) students conducted their three consecutive summer immersions (2008-2010) in Barangay Tinajero, Bacolor, the student's activities and their reflection on their experiences in the barangay.

The purpose of this study was to evaluate the changes of shear bond strengths and failure patterns in orthodontic resin adhesives according to the water immersion time. Metal brackets were bonded to the specimens involving the premolars with chemical-cured(Concise(R)) and light-cured(Transbond(R)) adhesives. The shear bond strength was measured on universal testing machine and the failure patterns were assessed with the adhesive remnant index(ARI) after storage in distilled water at 37degrees C for 1 day, 1 week and 1, 3, and 6 months, respectively. The results were as follows: 1. The shear bond strengths at the 6 month in both Concise and Transbond were significantly higher than those at the 1 day, 1 week and 1 month(P<0.05). There were positive correlations between shear bond strength and water immersion time in both Concise and Transbond(P<0.01). 2. There were no significant differences in shear bond strength between Concise and Transbond. 3. The brackets were failed primarily at the bracket base-adhesive interface and there was no significant difference in the incidence of ARI scores according to the water immersion time.
Adhesives* ; Bicuspid ; Immersion* ; Incidence ; Water*