European Journal of Prosthodontics and Restorative Dentistry

Colour Difference Between Caucasian and Afro-Caribbean Skin Tone Silicone Elastomer Moulded in Type II and Type III Dental Stone

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Cover Date

December 2019

Print ISSN

0965-7452

Electronic ISSN

2396-8893

Vol

27

Issue

4

Abstract

European Journal of Prosthodontics and Restorative Dentistry (2019) 27, 172–181

Colour Difference Between
Caucasian and AfroCaribbean Skin Tone Silicone
Elastomer Moulded in Type II
and Type III Dental Stone
ABSTRACT
Keywords
Dental Stone
Silicone Elastomer
Maxillofacial Prostheses
Colour Change

Authors
Anna Veli*

(AIMPT, BSc(Hons), MSc)

Address for Correspondence
Anna Veli
Email: [email protected]
* King’s College London

Aim: The colour stability of the silicone is essential for the longevity of facial prostheses.
This in vitro study investigates the colour degradation of two different skin shade silicones
moulded in Type II and Type III dental stone. Methods & Materials: Two different types of
dental stone were used to fabricate 168 silicone samples (n=42 for each group) using M511
maxillofacial silicone, which was coloured with Spectromatch Procolourants. The polymerisation was carried out at 85°C 1.5 hours. A spectrophotometer was used to record the
colour differences (ΔE) of each group before and after polymerisation. The CIEL*a*b* formula was used to obtain the measurements and a one-way ANOVA was carried out for the
statistical analysis of the data. Results: There is a statistically significant colour difference
(ΔE) for all groups. For the Afro-Caribbean skin tone, Type III dental stone demonstrated the
greatest colour change (ΔE = 4.36), whereas, for the Caucasian skin tone, it was the Type
II dental stone (ΔE = 2.21). Conclusion: This study showed that regardless of the investing
material, the colour of the silicone lightens after polymerisation. Both types of dental stone
resulted in visible colour changes, with a ΔE ranging from 1.64 - 4.36.

INTRODUCTION
The history of the facial prosthesis dates back to the Egyptians and the
Chinese, who fabricated auricular, nasal, and ocular prostheses using various materials, such as wax, resins, and metal.1,2 The purpose of maxillofacial prosthetics is to restore the form of missing or defective parts of the
body, which could be a result of a disease, injury or congenital deformity.
Restoration of these defects can be achieved by a surgical and/or a prosthetic approach, which aims to restore the patient’s appearance, improve
their self-esteem, and help them return to an active role in public life.3-5
The success of a restoration depends on the size and site of the defect,
the skills of the prosthetist, and the properties of the material used for
the restoration.6,7 Polymeric materials, including acrylic, polyurethane and
silicone elastomers, in particular, are some of the materials that have been
used worldwide for this purpose over the years. Silicone elastomers were
first used as maxillofacial material in 1960 by Barnhart,8 and quickly took
over the other materials. Although, this material exhibits some excellent
properties, it also has some frustrating deficiencies, such as degradation
of the properties over time, especially colour, which requires the renewal

Received: 18.02.2019
Accepted: 10.07.2019
doi: 10.1922/EJPRD_01914Veli13

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