Color stability of the artificial iris button in an ocular prosthesis before and after acrylic resin polymerization

Magnification of Iris through Clear Acrylic Resin in Ocular Prosthesis

The study on the magnification of the clear acrylic resin in prosthetic dentistry is important but lacking. Hence, this research aimed to investigate the magnification of the iris in the ocular prosthesis with various thicknesses of clear heat cure acrylic resin. A total of 60 ocular prostheses were divided into six groups with various thicknesses of clear heat cure acrylic resin over the iris; T0 (control): no acrylic resin, T1: 2, T2: 4, T3: 6, T4: 8, and T5: 10 mm of clear acrylic resin over the iris. Each ocular prosthesis was manufactured from white acrylic, with a 10.250 mm iris. Then, the clear heat cure resin was placed over the iris, cured, then polished. The final diameter of the iris was measured with a vernier caliper. The sizes of the iris were compared among various groups using one-way ANOVA, and a significant level was chosen at p value = 0.01. The mean sizes of iris were T0 = 10.25, T1 = 10.92, T2 = 11.26, T3 = 11.91, T4 = 12.75, and T5 = 13.43 mm. The size of the iris was significantly different among the group (p < 0.0001). The magnification of the iris for different groups was 1.06 for T1, 1.10 for T2, 1.16 for T3, 1.24 for T4, and 1.31 for T5. The magnification of the iris increased as the thickness of clear heat cure acrylic resin over the iris is increased on the ocular prosthesis.

Digital photographic technique for the production of an artificial eye

The use of hand painting an iris button using oil paint remains the conventional method of artificial eye manufacturing. The authors found that replacing this technique with a digital photograph taken of a patient's unaffected eye offers several advantages over the conventional method but the process from capture to print must be standardised and colour accurate. The authors of this paper suggest a tried and tested formulated photographic process of capture and printing prior to polymerisation. It discusses issues that can arise and how these can be overcome in order to achieve a high-quality print that can be used to produce a 'life like' ocular prosthesis.

Prostetic Rehabilitation of an Eye Globe: Case Report

Introduction

The lack of an eye has an immediate and long-term impact on a patient's life.

Aim

The aim of this study is to show a case of prosthetic rehabilitation of an eyeball.

Case report

Male patient, 60 years old, sought care at the Oral Oncology Center of the São Paulo State University "Júlio de Mesquita Filho", for the rehabilitation of the orbital cavity with an acrylic eye prosthesis. This prosthesis was made with thermopolymerizable acrylic resin and hand painted iris with oil paint on cardboard. The prosthesis was installed after finishing and polishing and the hygiene and general care instructions were explained.

Conclusion

In the present case, the patient was satisfied with the aesthetics and comfort of the prosthesis, which demonstrates the success of the treatment.

Effect of vulcanization temperature and dental stone colour on colour degradation of maxillofacial silicone elastomers

Background

Colour degradation is a major problem in maxillofacial silicone elastomers. Recent studies have focused on colour stability and the mechanical properties of the silicone elastomers. A colour match is also essential for the acceptance of the prosthesis by the patient. The aim of this study is to assess the colour degradation of the silicone elastomer after being moulded in different colours of dental stones at two different vulcanization temperatures.

Methods

Five different colours of dental stones were used to fabricate a total of 120 silicone blocks using a Cosmesil M511 maxillofacial silicone elastomer. Vulcanization was completed at two different temperatures (25 and 100° Celsius). Colour measurements were obtained with a Conica Minolta spectrophotometer. The CIEDE2000 formula was used to calculate the colour differences (∆E00). Two-way ANOVA, one-way ANOVA with Bonferroni corrected post-hoc p values and independent samples t-test were used for the statistical analyses.

Results

High temperature vulcanization causes lightening of the maxillofacial silicone elastomers without regard to the dental stone colour (p = 0.001). Specimens moulded in green stone lightened least at room temperature (p = 0.999). Compared to the control group, at high temperature, all specimens moulded in coloured dental stones darkened significantly (p < 0.001 for white, blue and yellow; p = 0.006 for green; p = 0.045 for reddish-brown). In the high temperature group, the shift to a green chroma was significant in the white, yellow and green dental stones groups (p = 0.001, p = 0.002, p < 0.001, respectively). The mean b* of the high temperature control group was higher than that of the room temperature control group (p < 0.001). The only ∆E00 score lower than the perceptibility threshold for dental materials (∆E00 = 1.30) was between the room temperature control group and the room temperature green dental stone group (∆E00 = 0.96).

Conclusions

Green and blue dental stones cause less colour degradation in silicone elastomers. Reddish-brown dental stones cause the most colour degradation in silicone elastomers. At 100 °C, the colour of the silicone elastomer lightens and yellows even if the elastomer is vulcanized in a stainless steel mould. White, yellow and reddish-brown dental stones make the silicone elastomer appear more yellow even if the elastomer is vulcanized at room temperature.