Restorative Dentistry & Endodontics

Discoloration of teeth due to different intracanal medicaments: Farzaneh Afkhami, Sadaf Elahy, Alireza Mahmoudi Nahavandi, Mohamad Javad Kharazifard, Aidin Sooratgar; Restor Dent Endod 2019;44(1):e10. Published online February 12, 2019; DOI: https://doi.org/10.5395/rde.2019.44.e10

Abstract PDF PubReader ePub: Objectives
The objective of this study was to assess coronal discoloration induced by the following intracanal medicaments: calcium hydroxide (CH), a mixture of CH paste and chlorhexidine gel (CH/CHX), and triple antibiotic paste (3Mix).
Materials and Methods
Seventy extracted single-canal teeth were selected. Access cavities were prepared and each canal was instrumented with a rotary ProTaper system. The specimens were randomly assigned to CH, CH/CHX, and 3Mix paste experimental groups (n = 20 each) or a control group (n = 10). Each experimental group was randomly divided into 2 subgroups (A and B). In subgroup A, medicaments were only applied to the root canals, while in subgroup B, the root canals were completely filled with medicaments and a cotton pellet dipped in medicament was also placed in the pulp chamber. Spectrophotometric readings were obtained from the mid-buccal surface of the tooth crowns immediately after placing the medicaments (T1) and at 1 week (T2), 1 month (T3), and 3 months (T4) after filling. The ∆E was then calculated. Data were analyzed using 2-way analysis of variance (ANOVA), 3-way ANOVA, and the Scheffé post hoc test.
Results
The greatest color change (ΔE) was observed at 3 months (p < 0.0001) and in 3Mix subgroup B (p = 0.0057). No significant color change occurred in the CH (p = 0.7865) or CH/CHX (p = 0.1367) groups over time, but the 3Mix group showed a significant ΔE (p = 0.0164).
Conclusion
Intracanal medicaments may induce tooth discoloration. Use of 3Mix must be short and it must be carefully applied only to the root canals; the access cavity should be thoroughly cleaned afterwards.

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Colorimetric comparison of single layered dental composite with double layered dental composite: Young-Sang Song, Ja-Hyun Kim, Bin-Na Lee, Ji-Hyun Jang, Hoon-Sang Chang, Yun-Chan Hwang, Won-Mann Oh, In-Nam Hwang; Restor Dent Endod 2012;37(2):84-89. Published online May 18, 2012; DOI: https://doi.org/10.5395/rde.2012.37.2.84

Abstract PDF PubReader ePub: Objectives
This study analyzed the difference in color caused by different thickness in enamel layer of composite resins when applied with single and layering placement technique, and evaluated if the results agreed with the shade guide from the manufacturers to verify reliability of the color matching process of the manufacturers.
Materials and Methods
For single composite resin samples, 6 mm diameter and 4 mm thickness cylindrical samples were fabricated using Ceram-X mono (DENTSPLY DeTrey) and CIE L^*a^*b^* values were measured with spectrophotometer. Same process was done for layering composite resin samples, making 3 dentinal shade samples, 4 mm thickness, for each shade using Ceram-X duo (DENTSPLY DeTrey) and enamel shade resins were layered in 2 mm thickness and CIE L^*a^*b^* values were measured. These samples were ground to 0.2 mm thickness each time, and CIE L^*a^*b^* values were measured to 1 mm thickness of enamel shade resin.
Results
Color difference (ΔE^*) between single and layering composite resin was 1.37 minimum and 10.53 maximum when layering thicknesses were between 1 mm and 2 mm and 6 out of 10 same shade groups suggested by manufacturer showed remarkable color difference at any thickness (ΔE^* > 3.3).
Conclusion
When using Ceram-X mono and duo for composite resin restoration, following the manufacturer's instructions for choosing the shade is not appropriate, and more accurate information for Ceram-X duo is needed on the variation and expression of the shades depending on the thickness of the enamel.

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Understanding of the color in composite resin: Jeong-Won Park; J Korean Acad Conserv Dent 2011;36(4):271-279. Published online July 31, 2011; DOI: https://doi.org/10.5395/JKACD.2011.36.4.271

Abstract PDF PubReader ePub

In clinic, esthetic restoration of a defective natural tooth with composite resin is challenging procedure and needs complete understanding of the color of tooth itself and materials used. The optical characteristics of the composites are different because the chemical compositions and microstructures are not same.

This review provided basic knowledge of the color and the color measurement devices, and analyze the color of the natural tooth. Further, the accuracy of the shade tab, color of the composite resins before and after curing, effect of the water, food and bleaching agent, and translucency, opalescence, and fluorescence effects were evaluated.

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Color difference of the dental composites measured by different color measuring instruments: Su-Jung Park, Eun-Young Noh, Hyun-Gu Cho, Yun-Chan Hwang, Won-Mann Oh, In-Nam Hwang; J Korean Acad Conserv Dent 2009;34(3):199-207. Published online May 31, 2009; DOI: https://doi.org/10.5395/JKACD.2009.34.3.199

Abstract PDF PubReader ePub

The objective of this study was to evaluate the effect of color measuring instrument by measuring the color of dental composite resins.

Nine shade light cured composite resin disks were prepared (diameter : 15 mm, thickness : 4 mm). CIE L^*a^*b^* color scale of each disk was measured with 3 different types of spectrophotometer [MiniScan XE plus (Model 4000S, Hunter Lab, USA), CM-3500d (Minolta, Japan) and Specbos 2100 Miniature VIS Reflection spectrometer (Serial No: 319416, JETI Technishe VIS Instrumentic GmbH, Germany)]. Miniscan XE Plus and CM-3500d using identical measuring geometry with different size of viewing aperture. But Specbos 2100 using different measuring geometry.

Within the limitation of this study, there were color difference (ΔE^*) from 2.4 to 7.8 between Miniscan XE Plus and CM-3500d, but L^*, a^*, b^* values showed the high correlation. However, there were great color difference (ΔE^*) in the extent of about 20 between instruments with the different measuring geometry.

Therefore, color scale measured by color measuring instrument should be used as a relative value rather than an absolute value in the field of dentistry.

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Effect of the bleaching light on whitening efficacy: Jong-Hyun Park, Hye-Jin Shin, Deok-Young Park, Se-Hee Park, Jin-Woo Kim, Kyung-Mo Cho; J Korean Acad Conserv Dent 2009;34(2):95-102. Published online March 31, 2009; DOI: https://doi.org/10.5395/JKACD.2009.34.2.095

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The aim of this study was to evaluate the influence of light energy on the tooth whitening effect of bleaching agent in vitro. Extracted human mandibular molars were sectioned to 2 fragments(mesial, distal) and lingual portions of crown were used in this study. All specimens were stained using a red wine for 24 hours and immersed in artificial saliva. Specimens divided into four groups, group 1 and 2 light-activated by LumaCool (LED, LumaLite, Inc., Spring Valley, USA), group 3 and 4 light-activated by FlipoWhite2 (Plasma acr lamp, Lokki, Australia). Group 1 and 3 bleached with LumaWhite(LumaLite, Inc., Spring Valley, USA), group 2 and 4 bleached with Polaoffice(SDI, Victoria, Australia). Bleaching treatment performed during 10 minutes every 24 hours and repeated 6 times. During bleaching treatment , distal fragments was light-activated(L) but mesial fragments was not(NL). Shade assessment employed before and after bleaching treatment using spectrophotometer. The results of the change in shade was compared and analysed between NL and L by using paired-sample T test with 95% level of confidence.

There were no significant differences between NL and L with a few exceptions. In group 2, a^* value more change in L, in group 3, b^* value more change in L, in group 4, a^* value less change in L. After bleaching, L^* value and ΔE increased in all groups and the value of a^* and b^* decreased in all groups.

Within the limitation of this test conditions, the results of this study indicate that the light energy has no obvious improving impact on the tooth whitening effect of a bleaching agent.

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Color changes in composite resins exposed to xenon lamp: Young-Gon Cho, Jeong-Il Seo, Soo-Mee Kim, Jin-Ho Jeong, Young-Gon Lee; J Korean Acad Conserv Dent 2003;28(3):195-202. Published online May 31, 2003; DOI: https://doi.org/10.5395/JKACD.2003.28.3.195

Abstract PDF PubReader ePub

The purpose of this study was to evaluate the color changes of the composite resin resulting from xenon lamp exposure in different environments. Composite resin (Z 250 ; shade A1, A2, A3, A3.5, and A4) were applied in a cylindrical metal mold. Seventy five specimens according to environments of exposure were made as follows;

Group I: aluminum foiling of the specimens in the air at 37℃ for 1 day and 7 days.

Group II: exposure of xenon lamp to the specimens in the air at 37℃ for 1 day and 7 days.

Group III: exposure of xenon lamp to the specimens in distilled water at 37℃ for 1 day and 7 days.

The color characteristics (L^*,a^*,b^*) of the specimens before and after exposure of xenon lamp were measured by spectrophotometer and the total color differences (ΔE^*) were computed.

The results obtained were as follows:

In all groups except A1 shade of group III, the ΔE^* values presented below 2.0, and group III showed the highest ΔE^* values followed by group II and group I in a decreasing order(p<0.05).

In all shades and groups, the more the exposure time of xenon lamp and the lighter the shade were, the higher the tendency for discoloration (p<0.05).

The composite resins which was exposed to xenon lamp in the distilled water was more discolored than those in the air (p<0.05).

The major changes of composite resins which were exposed to xenon lamp in the air were an increase in yellowness through a positive shift of the b^* value, and those in the distilled water were an increase in darkness and yellowness through a negative shift of the L^* value and a positive shift of the b^* value.

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