Thesis
Effect of time and temperature on the color stability of dental composite
University of Iowa
Master of Science (MS), University of Iowa
Summer 2019
DOI: 10.17077/etd.yanr-n70a
Abstract
<p>OBJECTIVE: To evaluate the effects of different times and temperatures of coffee exposures on the color stability of three types of dental composites (DC).</p>
<p>METHODS: Three types of DC were used to fabricate standardized discs (n=288; n=96/DC): microfill (Durafill VS), microhybrid (Z100TM), and nanofill (Estelite OMEGA) of shade A2. Each disc was 2mm in thickness and 9mm in diameter. After being light cured with a Quarts tungsten halogen (QTH) unit at the energy level recommended for each DC, discs were polished using sand paper under water irrigation. All samples were initially stored in an incubator in distilled water for 24-hours at 37 65ºC and each DC group was further divided into 6 subgroups (n=16/per group): 65ºC coffee, 37ºC coffee, 4ºC coffee, 65ºC distilled water, 37ºC distilled water, 4ºC distilled water (control group with water media). Baseline color was measured by spectrophotometer (Easy VITA shade compact) with color changes (ΔE*) recorded after 1-day, 3.5-days, and 7-days. The statistical analysis revealed no interactions between DC, temperature, and time of incubation and the main effects were examined using one-way ANOVA followed by the post-hoc Tukey’s HSD test or a Bonferroni adjustment (alpha=0.05).</p>
<p>RESULTS: Mean (ΔE*) observed with coffee exposures for the microfill DC (11.58±6.37) was statistically significant higher than for the nanofill DC (10.64±6.77; p<0.001), and mean (ΔE*) for the nanofill DC was significantly higher than for the microhybrid DC (9.26±5.83; p<0.001). For all DC, mean (ΔE*) observed with coffee exposure at 65ºC (18.33±4.32) was significantly higher than at 37°C (7.03±2.05; p<0.001), and mean (ΔE*) at 37ºC was significantly higher than at 4ºC (6.11±2.67; p<0.001). Mean (ΔE*) after coffee exposure for 1 day (8.64±5.35) was significantly lower than for 3.5-days (11.07±6.50; p<0.001) and 7-days (11.76±6.84; p<0.001); while no difference was observed between 3.5-days and 7-days of incubation (p=0.0769).</p>
<p>CONCLUSION: The findings of this study indicated that exposure time, temperature, and composite type affect the color stability of DC, with higher temperature affecting the color stability more than lower temperatures. Also, color stability was affected more by increasing the exposure time.</p>
Details
- Title: Subtitle
- Effect of time and temperature on the color stability of dental composite
- Creators
- Arwa Ali Alhakami - University of Iowa
- Contributors
- Rodrigo Rocha Maia (Advisor)Cristina D. Vidal (Committee Member)Teresa Marshall (Committee Member)Fang Qian (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Operative Dentistry
- Date degree season
- Summer 2019
- Publisher
- University of Iowa
- DOI
- 10.17077/etd.yanr-n70a
- Number of pages
- xv, 115 pages
- Copyright
- Copyright © 2019 Arwa Ali Alhakami
- Language
- English
- Date submitted
- 11/06/2019
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 111-115).
- Public Abstract (ETD)
To restore tooth structure, dental composites have been used for decades in dentistry. Dental composites are one of the most used materials in dentistry due to their esthetic properties, ability to bond to tooth surface, and their adequate strength. An esthetic restoration should resemble the overall appearance of natural teeth and color is an important point. Multiple studies revealed that color stability of dental composite has been a problem. In the oral cavity restorative materials are exposed to thermal changes as a result to the intake of food and beverages.
In this study we evaluated the effect of different coffee temperatures for different lengths of time on the color change of three commercially available dental composites with different composition that are commonly used in the anterior region. After sample fabrication (n=288) color measurement was done using a spectrophotometer, which is a device that can quantify color. The samples were then randomly and equally divided into either coffee or water into 6 subgroups (n=16); hot coffee, neutral coffee, cold coffee, hot water, neutral water, cold water (control group with water media). Color changes were recorded after 1-day, 3.5-days, and 7-days of exposure to either coffee or water media.
Within the limitations of the study we concluded that color change was affected by composite type, color stability was affected more with increasing exposure time, and higher temperatures affected the color more than lower temperature.
- Academic Unit
- Operative Dentistry
- Record Identifier
- 9983776889902771
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