Yawar Ali Abidi¹                                   BDS, FCPS

Sameer Quraeshi²                               BDS, MSc

Syed Ahmed Omer³                            BDS, MSc,

Murtaza Raza Kazmi⁴                        BDS, FCPS

Saqib Rashid⁵                                       BDS, MSc, FCPS 

INTRODUCTION

To fulfill the esthetic demands of patient toothcolored restorative materials have been widely used in dentistry¹. Different type of dental composite resins are available in the dental market and they are classified according to shape, size and distribution of fillers². Nowadays Nanocomposite is widely used in clinical practice. Nanocomposite contains filler size ranging from 0.01-0.04mm³. It has many advantages such as increase mechanical properties, high wear resistance and low polymerization shrinkage⁴. Despite these advantages some problems still remain and one of them is color stability which is the ability of material to be able to retain its original color⁵. Dental composite resin content has been reported as being critical to color stability and leads to discoloration⁵. Discoloration of esthetic restorative material is caused by several intrinsic and extrinsic factors. Intrinsic stain is due to alteration of the resin matrix itself ⁶, However, extrinsic factors include staining by exogenous sources such as tea, coffee, beverages and mouth rinses. These agents cause discoloration by absorption and adsorption of colorants⁷.

Color evaluation can be done by visual method or by instrumental methods. In visual method an observer assesses the color change of the sample against white background, while in instrumental method devices such as Spectrophotometer, Calorimeters and computerized image analysis are used⁸.

The spectrophotometer measures wave lengths of transmitted light of specimen⁹. This instrument uses the (CIE) L*a*b* color system. This system consists of the following Parameters: L*, which refers to luminosity (white to black); a*, which refers to the red-green color axis and b*, which refers to yellow-blue axis⁹. Even though there are a number of studies on evaluating the staining power of commonly used products in daily life such as tea, coffee, soft drinks, chlorhexidine containing mouth rinses¹, but no reports were found with regards to staining power of different lipsticks which is commonly used by female patients and is available with different fixers in market. There are a few clinical and in vitro studies which reported that these lipsticks have capability to causes alterations in color of composite resins¹⁴. Thus, there is great need to find the staining capability of lipsticks with common and ultra fixers and also considering the contact time with esthetic dental materials.

This study estimates superficial color alteration of composite resin stained with two different types of lipsticks (one with common fixer and the other with ultra fixer) at different time intervals, immediately, 1 hour and 24 hours after curing.

The hypotheses tested were:

• The composite resin shows color alteration when stained with lipstick;
• The composite resin shows color alteration when stained 24 hour after polymerization.
• Lipstick with ultra fixer show more color alterationof composite then lipstick with regular fixer.

METHODOLOGY

PREPRATION OF SPECIMEN

In this study, 90 specimens of nanocomposite FiltekTM Z350 XT shade A3 (3M ESPE, St.Paul, MN, USA) were made using poly tetra fluoroethylene mold (10mm in diameter and 2mm of thickness). All materials were prepared according to manufacturers’ instructions (Table I). Composite resin was placed in one increment in mold

Table I: The detail of materials  used in this study

and overfilled, to avoid air bubbles and inclusion mold covered with mylar strips and compressed with glass slides on the upper and lower surface. Samples were light cured at the distance of 1 mm for 40 seconds on each side with LED curing lamp Mectron (Intensity 1000mw/cm2 starlight pro-led curing lamp, Italy). After curing glass slide and mylar strips were removed. The discs were polished with coarse, medium, fine and ultra fine Discs (Sof-Lex Pop-On; 3M ESPE, St. Paul, MN, USA). After preparation discs were divided in 9 groups (n=10) according to time interval between curing and contact with both lipsticks.

Two same color lipsticks represented pigmenting agents. One lipstick had common fixer and other had ultra fixer.

COLOR ANALYSIS

Color measurement were performed with a spectrophotometer (Data color; SF 600; Plus-CT; USA, Efroze Textile mills F.B.Area, Karachi) using CIE L*a*b*(Comission International l´Eclairage) system. The analyzed color parameters were the values for L*, a* and b*. Where L* is the luminosity, a* represent the color variation between green-red and b* represent the color variation between blue-yellow. DE is the total color variation. The total color variation was calculated according to following equation.

DE*ab = [(DL*)² + (Da*)²+ (Db*)²]¹/²

The spectrophotometer was calibrated before each color analysis session of discs in accordance with manufacturer’s instruction.

For color analysis each discs was placed inside the central orifice of the white, opaque Teflon matrix. A mortise device was placed on the white Teflon, which was positioned over the disc to standardize the contact of the tip from the spectrophotometer to disc surface at 90^o angle.

STAINING PROCEDURE

Study group divided according to time interval between curing and staining with lipstick and type of fixer in the lipstick detail of groups given in table II

For the groups (G1, G4 and G7) at 0 hours after curing discs surfaces were cleaned and dry with absorbent paper. Base line colors of the discs were recorded (average of 3 readings).

G1 was not stained. G4 was stained with common fixer lipstick only single coat in one direction is applied. G7 was stained with ultra fixer lipstick in a same manner like G4. These discs were then kept in dry conditions for 1 hour, after which the excess lipstick was removed with absorbent paper. Then the final color readings of the discs were taken (average of 3 readings).

For the groups (G2, G5 and G8) same procedure is repeated after 1 hour of curing. Discs were stored in artificial saliva at 37^oC. For the groups (G1, G4 and G7) same procedure is repeated after 24 hour.

STATISTICAL ANALYASIS

Statistical analysis was computed with Statistical Package for Social Sciences (SPSS) software, version 16.00 (SPSS Inc, USA). Descriptive analysis was executed in the form of mean and standard deviation for change in color. ?E values were tested for significant difference at (0.05 level of significance) using two-way ANOVA with repeated measurement and Tukey’s Honestly Significant Difference (HSD) for multiple comparisons.

RESULTS

Means and SD are  shown in table II

There was no statistically significant difference between the control group and group stained with common fixer lipstick (p>0.05), but there was statistically significant difference between the group stained with common fixer

Table II Mean and standard deviation

lipstick and group stained with ultra fixer lipstick (p<0.05). Statistically significant difference was also seen between

control group and group stained with ultra fixer lipstick. The composite resin showed more color change with both lipsticks as compare to control group.

With respect to time period there were statistically significant differences seen between all the groups at three different time periods (p<0.05). Statistically significant differences were seen at 0 hour, 1 hour and 24 hour.

DISCUSSION

There are a number of methods used for color determination of teeth and tooth color restorative material in dentistry. It is broadly categorized in two categories, instrumental and visual means⁹. Variability of results in colour determination among different observer is due to many factors including the observed object and position of observed object relative to observer, color distinctiveness of illuminate metamerism, perception of observer¹⁰. For this reason instrument measurement has been suggested, because it reduces subjective elucidation of visual color comparison, therefore, spectrophotometers and colorimeters are more extensively used today¹¹. Due to these facts, the current study used the instrumental technique with a spectrophotometer recording the color values with the CIE (Comission International l´Eclairage) L* a*b* system. This system has the capability to find out the color change value DE.

In 1989 Johnston and Kao recommend that value of DE < 3.3 was not visually perceptible so change in color in this range is esthetically acceptable. However, DE >3.3 gives clinically visual perception of color change and is deemed esthetically unacceptible¹².

The present study observed that, composite resin discs treated with ultra fixer lipsticks showed high staining index as compared to control groups and groups that were treated with common fixer, it proved our first hypothesis. These values are clinically unacceptable (DE>3.3) results are in agreement with result reported by Douglas et al¹³. Moreover, composite resin discs in control group show little color change at different time intervals, it might be caused by dehydration of composite resin or it is the continuation of cure. This change in color was considered as normal and esthetically acceptable, our results are in accordance with Avilmar et al which concluded that values of DE were much lower in control group and visually acceptable¹⁴. However, staining caused by both lipsticks was probably due to hydrophilic nature of matrix and increase vulnerability of water sorption in polymer¹⁵. As a result of this, composite resins absorbs coloring pigments in lipstick which results in discoloration. According to Ferracane et al⁹ composite resin show high absorption initially only but our results are not in agreement with it because discoloration of composite was high even at 24 hour after curing similar to color change in initial hours so the second hypothesis of present study was also accepted. Composite resins showed higher color change with ultra fixer lipstick at three different times (0 hr,1 hr and 24hrs) as compared to lipstick with common fixer, this also confirms the third hypothesis of present study.

There is necessity of more studies on staining power of different kind of lipsticks. Similar studies have reported

the effect of commonly utilized drinks such as tea, coffee, red wine and different mouth washes^17-20. We used only one brand of composite resin in our study,  therefore the results cannot be generalized. Also, only single brand of lipstick was used. Future studies addressing these limitations are recommended. Other clinical variables such as the frequency of reapplication of lipstick and the action of the tongue in terms of cleaning the stained resin restoration surface should be further analyzed. The results of our study must be interpreted with caution due to above mentioned limitation. It is recommended to instruct female patients to avoid the use of lipsticks for at least first 24 hours of composite resin based restoration on anterior teeth.

CONCLUSIONS

Groups with ultra fixer caused greater staining than other groups, so lipstick wearers should be warned to avoid the use of lipsticks with ultra fixers after receiving composite restoration in anterior teeth for at least 24 hours.

REFERENCE

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       1. Associate Professor & Head Department of Operative Dentistry Dr. Ishrat ul Ibad Khan Istitute of Oral Health Sciences, Dow University of Health Sciences.

       2.Assistant Professor, Department of Prosthodontics Fatima Jinnah Dental College and Hospital.    Email: escue3@gmail.com

       3.Assistant Professor & Head Department of Science of Dental Materials Bahria University Medical & Dental College.

       4.Assistant Professor, Head Department of Prosthodontics Fatima Jinnah Dental College and Hospital.

       5.Professor, Head Department of Operative Dentistry Fatima Jinnah Dental College and Hospital.

Corresponding author: “Dr Yawar Ali Abidi ” < yawar_aliabidi@hotmail.com >