Color Stability of Denture Base Acrylic Resins in Three Food Colorants an Invitro Study

SynopsisSynopsis

ColorColor stabilitystability ofof denturedenture basebase acrylicacrylic resinsresins inin threethree foodfood colorantscolorants –– AnAn invitroinvitro studystudy

By: Dr. Deepa J. Post Graduate Student Department of Prosthodontics Bangalore Institute of Dental Sciences & Hospital Bangalore - 560029 RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES KARNATAKA, BANGALORE. ANNEXURE - II

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION

1. Name of the candidate and DR. DEEPA J. address (In Block Letters) DEPARTMENT OF PROSTHODONTICS, BANGALORE INSTITUTE OF DENTAL SCIENCES AND HOSPITAL, 5/3, HOSUR ROAD, BANGALORE – 560029. 2. Name of the Institution Bangalore Institute of Dental Sciences and Hospital & Post Graduate Research Centre 3. Course of study and subject Master of Dental Surgery (MDS) Prosthodontics 4. Date of Admission May 2007 5. Title of the Topic Color stability of denture base acrylic resins in three food colorants – An invitro study 6. BRIEF RESUME OF THE INTENDED WORK:

6.1 Need for the Study

Almost all complete dentures are fabricated using acrylic resins. A low cost material that requires relatively easy manipulation and construction methods. However, it is not the ideal material in every respect. Discoloration of acrylic resins results in aesthetic problems, and a denture base polymer should have good aesthetics with a smooth and glassy surface and be capable of matching the natural appearance of the soft tissues. For the best aesthetic effect color and translucency should be maintained during processing and these resins should not get stained or change color in clinical use. In this study, the color stability of three commercially available denture base acrylic resins (Acralyn-H, DPI, Lucitone 199) is studied in three food colorants (Ponceau 4R, Tartrazine, Indigo Carmine) invitro to provide important information on the serviceability of these materials. 6.2 Review of Literature

1. This study1 compared a photographic method for assessing color change with an instrumental colorimetric procedure. Two denture base resins, a cold cure (Truveld Acrylic) and heat cure (Ideal acrylic) were stained in five different liquids such as coffee, tea, Coca-cola, hot distilled water and cold distilled water. The optical density changes of color transparencies were measured with a transmission densitometer. Good agreement with the colorimetric technique was obtained after fifteen days of staining over a range of F-stops and band pass filters. This study concluded that absolute density readings are dependent upon particular densitometer filter used. It also showed that photographic method is not sensitive to F-stop. The cold cure resins stained more, and also with hotter solutions demonstrating greater staining. This photographic technique appears to offer promise as a clinical method for determining color changes due to staining which correlates with spectrophotometric data.

2. This study2 evaluated the color stability of five denture base acrylic resins and one denture base repair resin. The samples were subjected to conditions of accelerated aging to test color stability. Five samples of each material were processed and aged for 100 and 300 hours. The color stability was quantitatively measured using the Minolta Chroma Meter II. Color measurements were made before weathering and at 100 and 300 hours the color difference E was calculated for all samples. It was found that 1) The color of Lucitone Hy- Pro and Acron was least affected by conditions of accelerated aging. 2) Triad, Accelar 20 and Perm demonstrated noticeable color changes and 3) Compak-20 had an appreciable color change and was the least color stable of the materials tested.

3. This study3 evaluated the color stability by reflection spectrophotometry after accelerated aging using heat and chemically activated acrylics processed by compression molding or fluid resin matrix techniques for fabrication of partial dentures. Samples of heat activated (L199, PDON, SB) and chemically activated (PR, PVAR, SC) denture base acrylics were polymerized according to manufacturers instructions. Samples were aged in an artificial aging chamber and color was measured by CIE (Commission Internationale de L’ Eclairage) L* a* b* on the reflection spectrophotometer at baseline and after each of three aging cycles. The heat activated acrylics tested were more color stable than two of the chemically activated acrylic. But one chemically activated acrylic (PVAR) recommended for a fluid resin matrix technique was color stable. 4. This study4 determined whether chemical disinfectants altered the surface texture or inherent color of denture base resins. Five chemical disinfectants (Clorox, Banicide, Cidex-7, Biocide and Multicide) in combination with five denture resins (Dentsply reline material, Hygenic HyFlo, Hygenic Perm, Lucitone 199 and Triad VLC reline resin) were evaluated at four different times of immersion (10 minutes, 30 minutes, 24 hours and 7 days). Surface roughness data were recorded with a surface analyzer. Color data CIE (Commission Internationale de L’ Eclairage) L* a* b* color space were measured with a colorimeter. Data were analyzed with repeated measures analysis of variance. It was found that one disinfectant (Multicide) cannot be used on all five resins and the remaining four disinfectants can be used on any of the five resins for upto a period of 30 minutes. Lucitone 199 resin can be immersed in any of the four disinfectants for upto 7 days without perceivable color change.

5. This study5 evaluated the color stability of five commercially available denture base acrylic resins (QC-20, Meliodent, Trevolon, Trevolon HI and Lucitone). The specimens were exposed to 3% Erythrosine, Tartrazine and Sunset yellow solution at 23o C  1o C. Color changes were determined with a computer controlled spectrophotometer. In this study, Lucitone QC-20 acrylic resin specimens exhibited noticeable color change or staining in compliance with National Bureau of Standards unit system. Changes in the other acrylic resins in the three solutions were slight and at trace level. All materials tested were acceptable in the standpoint of color stability for long term exposure to these food colorants.

6. This study6 evaluated the physical properties of a modified denture base resin for denture fabrication. Specimens made from heat polymerized resin Lucitone 199 were used as the control group. The two experimental groups, E-10 and E-20 had 10% and 20% respectively of the monomer substituted with an experimental phosphate containing monomer. The flexural strength and modulus, water sorption, solubility and color stability tests were conducted. The three groups were tested for color stability and changes in L* a* b* values were observed after exposure to UV radiation for 24 hours. All three resins showed visually non perceptible changes in E values, though Lucitone199 had the smallest increase E values, while E-20 had the highest increase. 6.3 Objectives of the study

 To evaluate the color stability of three commercially available heat cure denture base acrylic resins.

 To study the effect of duration and immersion (1 month, 3 months and 6 months) in three food colorants on the color stability of heat cure denture base acrylic resins.

7. MATERIAL AND METHODS 7.1 Source of data

Three commercially available heat cure denture base acrylic resins: 1. Lucitone 199 (Dentsply India Ltd.) 2. Acralyn –H (Asian Acrylates) 3. DPI – Heat cure acrylic resin (Dental Products of India Ltd.)

According to Rule 28 of Indian Prevention Food Adulteration Act, the following synthetic food colors are used: 1. Ponceau 4R – Red 2. Tartrazine – Yellow 3. Indigocarmine – Blue

7.2 Method of collection of data (including sampling procedure, if any)

1. Four stainless steel rectangular plates measuring 20mm in length, 10mm in width and 2.5mm in thickness are made to meet the demands of the measuring instruments. 2. 135 specimens are fabricated; 45 for Lucitone 199, 45 for Acralyn-H and 45 for DPI.

Preparation of the samples:

1. Four stainless steel rectangular plates measuring 20mm in length, 10mm in width and 2.5mm in thickness is invested in flasks using dental stone.

2. After the dental stone is completely set the rectangular plate is removed and the mould cavity in the stone is then packed with heat polymerized acrylic resin and cured using the specific curing cycle.

3. The dental stone is lubricated with a thin layer of separating media. The monomer and polymer of the heat polymerized acrylic resin (Lucitone 199, Acralyn H, DPI) is proportioned, mixed, packed and pressed in the mould following manufacturer’s instructions.

4. After polymerization of the resin, the flasks are allowed to cool at room temperature before opening. The rectangular resin specimens are then deflasked.

5. A total of 135 specimens are fabricated, 45 for each type of resin. The specimens are first divided into three groups for each test solution and then for each solution 5 specimens are coded (from 1 to 5) on the back of specimens and are immersed for a duration of 1 month, 3 months and 6 months.

6. Dyes that are frequently used in the coloring of food, Ponceau 4R, Tartrazine, Indigo Carmine are prepared by dissolving three grams of dye in 100ml of distilled water. Solutions prepared are poured into sealable jars and 5 specimens are placed in each jar. The specimens are then stored in 3 solutions for 1 month, 3 months and 6 months period at room temperature.

7. Experimental recordings are taken before immersion and after 1 month, 3 months and 6 months of exposure to staining solutions. Before any readings, the specimens are removed and rinsed in distilled water and excess water is removed with tissue paper and specimens are allowed to dry.

8. Color measurements are made in 3 randomly selected areas by using an ultraviolet-visible recording spectrophotometer.

9. The readings are statistically analyzed to arrive at a conclusion.

7.3 Does the study require any investigations or interventions to be conducted on patients or other humans or animals? If so, please describe briefly.

No / Not Applicable.

7.4 Has ethical clearance been obtained from your institution in case of 7.3?

Not Applicable 8. LIST OF REFERENCES 1. W. T. WOZNIAK, T. P. MULLER, R. SILVERMAN and J.B. MOSER, Photographic assessment of color changes in cold and heat-cure resins, Journal of Oral Rehabilitation, 1981; 8: 333-339.

2. KENNETH B. MAY, MICHAEL E. RAZZOOG, ANDREW KORAN and EMERSON ROBINSON. Denture base resins: Comparison study of color stability. Journal of Prosthetic Dentistry, 1992; 68: 78-82.

3. XINZHI WANG, JOHN M. POWERS, MARK E. CONNELLY, Color stability of Heat-Activated and Chemically Activated Fluid Resin Acrylics, Journal of Prosthodontics, 1996; 5: 266-269.

4. TSUN MA, GLEN H. JOHNSON AND GLENN E. GORDON. Effects of chemical disinfectants on the surface characteristics and color of denture resins, Journal of Prosthetic Dentistry, 1997; 77: 197-204.

5. NUR HERSEK, SENAY CANAY, GÜLAY UZUN and FATIH YILDIZ, Color stability of denture base acrylic resins in three food colorants, Journal of Prosthetic Dentistry, 1999; 81: 375-379.

6. GUNJAN DHIR, DAVID W. BERZINS, VIRENDRA B. DHURU, A. RAJ PERATHAMBY and ANDREW DENTINO. Physical properties of denture base resins potentially resistant to Candida adhesion. Journal of Prosthodontics, 2007; 16: 465-472.

9. Signature of the candidate

(Dr. Deepa J) 10. Remarks of the Guide 11. NAME & DESIGNATION OF (IN BLOCK LETTERS) 11.1 Guide Dr. G. R. Rahul, Professor & Head, Department of Prosthodontics, Bangalore Institute of Dental Sciences and Hospital, Bangalore 11.2 Signature

11.3 Co-Guide (if any)

11.4 Signature

11.5 Head of Department Dr. G. R. Rahul Professor & Head, Department of Prosthodontics, Bangalore Institute of Dental Sciences and Hospital, Bangalore 11.6 Signature

12 12.1 Remarks of Chairman and Principal 12.2 Signature