Effect of Mouthwashes for COVID-19 Prevention on Surface Changes of Resin Composites.

OBJECTIVE: The aim of this research was to investigate the effect of various mouthwashes for COVID-19 prevention on surface hardness, roughness, and colour changes of bulk-fill and conventional resin composites and determine the pH and titratable acidity of mouthwashes. METHODS: Four hundred eighty specimens were fabricated in cylindrical moulds (10 mm in diameter and 2 mm in thickness). Before immersion, baseline data of surface hardness, roughness, and colour values were recorded. Each product of specimens (Filtek Z350XT, Premise, Filtek One Bulk Fill Restorative, SonicFil 2) were divided into 4 groups for 0.2% povidone iodine, 1% hydrogen peroxide, 0.12% chlorhexidine, and deionised water (serving as a control). The specimens were immersed in mouthwashes for 1 minute and then stored in artificial saliva until 24 hours. This process was repeated for 14 days. After immersion, surface hardness, roughness, and colour values of specimens were measured at 7 and 14 days. The data were statistically analysed by 2-way repeated analysis of variance, Tukey honestly significant difference, and t test (P < .05). RESULTS: After immersion, all mouthwashes caused significantly lower surface hardness and greater roughness and colour values (P < .05) on all resin composites tested. CONCLUSIONS: Mouthwashes had an effect on all resin composites evaluated leading to a significant decreased surface hardness and an increased roughness and colour values (P < .05).

In vitro surface and color changes of tooth-colored restorative materials after sport and energy drink cyclic immersions.

BACKGROUND: There has not been any research conducted on surface properties and color changes from sport and energy drinks on bulk-fill resin composite, nanohybrid resin composite and glass ionomer restorative material. The aim of this in vitro study was to investigate the effect of sport and energy drinks on surface hardness, roughness and color changes of bulk-fill resin composite, nanohybrid resin composite and glass ionomer restorative material, and to also evaluate the acidity and titratable acidity of the drinks. METHODS: One hundred and forty-seven specimens of each tooth-colored restorative material were prepared in a polytetrafluoroethylene mold (10 mm. in diameter and 2 mm. in thickness). Before immersion, baseline data of hardness, roughness, and color value were recorded. Each material was divided into 3 groups for sport drink, energy drink, and deionized water (serving as a control). The specimens were immersed in a storage agent for 5 s, then in artificial saliva for 5 s alternately for 24 cycles, and then stored in artificial saliva for 24 h. The immersion cycle was repeated for 14 days and hardness, roughness and color values were measured at 7 and 14 days. RESULTS: After immersion, the glass ionomer restorative material had statistically less hardness, more roughness and more color changes than the others (P < 0.05). Energy drink groups statistically caused more surface and color changes than sport drink groups (P < 0.05). CONCLUSION: Sport and energy drinks affected hardness, roughness, and color changes in all the tooth-colored restorative materials evaluated.

Degradability of bulk-fill resin composites after cyclic immersion in different distilled alcoholic beverages.

OBJECTIVES: To investigate effect of distilled alcoholic beverages on surface hardness, roughness, and erosion of bulk-fill resin composites. MATERIALS AND METHODS: Sixty eight specimens of each bulk-fill resin composite (Filtek One Bulk Fill Restorative, SonicFill 2, and Tetric N-Ceram Bulk Fill) were prepared. Baseline data of surface hardness and roughness value were recorded. The specimens were divided into five groups: vodka, whisky, tequila, brandy, and deionized water (served as a control). Specimens were then alternately immersed in 25 ml of a storage agent for 5 s and in 25 ml of artificial saliva for 5 s over 10 cycles. This process was repeated for 14 days. After immersion, specimens were subjected to evaluation of surface hardness, roughness, and erosion on days 7 and 14. The data were statistically analyzed by two-way repeated analysis of variance, Tukey's honestly significant difference, and a t test (p < 0.05). RESULTS: Distilled alcoholic beverages caused significant hardness decrement, roughness and erosion increment (p < 0.05), where the greatest degradation was found in brandy group. Tetric N-Ceram Bulk Fill had the most significant decrement in hardness and increment in roughness and erosion than the other resin composites (p < 0.05). CONCLUSION: Distilled alcoholic beverages affected hardness, roughness, and erosion of all the bulk-fill resin composites. CLINICAL SIGNIFICANCE: Regarding the bulk-fill resin composites tested, Filtek One Bulk Fill Restorative was the most appropriate restorative material in patients who consume distilled alcoholic beverages.

The effect of curing time by conventional quartz tungsten halogens and new light-emitting diodes light curing units on degree of conversion and microhardness of a nanohybrid resin composite.

BACKGROUND: Little is known about the relationship between the minimal light-curing time required for proper polymerization on various quartz-tungsten-halogen (QTH) and light-emitting diode (LED) light-curing units that have different light intensities. AIM: To evaluate the effects of curing time by QTH and LED light-curing units on the degree of conversion (DoC) and surface microhardness of a nanohybrid resin composite. SETTING AND DESIGN: Experimental design. MATERIALS AND METHODS: One hundred and twenty cylindrical specimens (4.0 mm in diameter, 2.0 mm thick) of shade A2 resin composite were prepared and polymerized with either QTHs or LEDs for 20 and 40 s. The DoC and the top and bottom surface microhardness were recorded. STATISTICAL ANALYSIS USED: Two-way analysis of variance, Tukey's test, and the t-test (α = 0.05) were used. RESULTS: Surface microhardness and DoC values were affected by light intensity and curing time (P < 0.05). In terms of microhardness and DoC, LED groups gave significantly more values than QTH groups (P < 0.05). CONCLUSION: Curing time affected surface microhardness and DoC values of a nanohybrid resin composite in both conventional QTH and new LED light-curing units.

Surface changes of various bulk-fill resin-based composites after exposure to different food-simulating liquid and beverages.

OBJECTIVE: To evaluate surface roughness, hardness, and morphology changes of various bulk-fill resin composites eroded by different food-simulating liquids and beverages. MATERIALS AND METHODS: One hundred and thirteen specimens were fabricated in polytetrafluoroethylene cylindrical mold (10 mm in diameter and 4 mm in thickness). Before immersion, baseline data of roughness, Vicker's microhardness were recorded and surface characteristics were examined using scanning electron microscopy (SEM). Each product of specimens (SDR, Dentsply; SonicFill, Kerr; Tetric N-Ceram Bulk Fill, Ivoclar Vivadent AG; and Filtek Bulk Fill, 3M ESPE) were divided into 5 groups for spicy and sour soup, spicy soup (Tom Yum), pineapple juice, passionfruit juice, and deionized water (served as a control). Specimens were then alternately immersed in storage agents for 5 seconds and artificial saliva for 5 seconds over 10 cycles. Specimens were stored in artificial saliva for 22 hours. This process was repeated for 28 days. After immersion, surface hardness and roughness of specimens were evaluated at 7, 14, 21, and 28 days and data were analyzed by two-way repeated ANOVA and Tukey's HSD (α = 0.05). Surface morphology of specimens was also examined on day 28. RESULTS: The SDR group had the most statistically significant decrement in hardness (25.65 ± 1.74 kg/mm2 in mean difference) and increment in roughness (0.26 ± 0.10 µm in mean difference; P < .05). Passionfruit juice caused the most surface changes in bulk-fill resin composites. SEM photomicrographs showed surface changes of all resin composites in varying degrees. CONCLUSION: Acidic food-simulating liquids and beverages significantly increased the surface roughness and decreased surface microhardness of bulk-fill resin composites after evaluation at the end of the 28-day immersion period. CLINICAL SIGNIFICANCE: For restoration of the affected teeth in patients who consume acidic food and beverages, roughness and erosion of resin composites should be considered. All of bulk-fill resin-based composites except SDR may be suitable for restorations in these patients.

The effect of red and white wine on color changes of nanofilled and nanohybrid resin composites.

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.

The effect of different beverages on surface hardness of nanohybrid resin composite and giomer.

AIMS: To investigate the effects of five beverages (apple cider, orange juice, Coca-Cola, coffee, and beer) on microhardness and surface characteristic changes of nanohybrid resin composite and giomer. MATERIALS AND METHODS: Ninety-three specimens of each resin composite and giomer were prepared. Before immersion, baseline data of Vicker's microhardness was recorded and surface characteristics were examined using scanning electron microscopy (SEM). Five groups of discs (n = 18) were alternately immersed in 25 mL of each beverage for 5 s and in 25 mL of artificial saliva for 5 s for 10 cycles. Specimens were then stored in artificial saliva for 24 h. This process was repeated for 28 days. After immersion, specimens were evaluated and data were analyzed by two-way repeated analysis of variance (ANOVA), Tukey's honestly significant difference (HSD), and a t-test (α = 0.05). RESULTS: Microhardness of all groups significantly decreased after being immersed in the tested beverages (P < 0.05). SEM photomicrographs presented surface degradation of all groups. CONCLUSIONS: The effect of these beverages on the surface of both restorative materials also depended upon the exposure time and chemical composition of the restorative materials and beverages.

Optimal depth of cure for nanohybrid resin composite using quartz tungsten halogen and new high intensity light-emitting diode curing units.

This study sought to evaluate the effects of quartz tungsten halogen (QTH) and light-emitting diode (LED) photocuring units on the degree of conversion (DC) and surface microhardness of a resin composite that had been cured for optimal depth of cure (DoC) assessment. Two hundred and forty cylindrical specimens (4.0 mm in diameter, 2.0-4.0 mm thick) of shade A2 resin composite were prepared and cured with either a QTH or an LED. The DC and top and bottom surface hardness were recorded, and data were analyzed using 2-way ANOVA, Tukey's test, t-test (α = 0.05) and linear regression analysis. The results showed that surface microhardness values and DC were affected by light intensity (P < 0.01), and resin composite thickness (2, 3, and 4 mm) (P < 0.01). Resin composite polymerized by the QTH had an optimal DoC of 3 mm, compared to 4 mm for the LED.