Elbashti M, et al. J Adv Prosthodont. 2016 Jun;8(3):219-223. http://dx.doi.org/10.4047/jap.2016.8.3.219

Manjin Zhang, BDS, DDS/Mariko Hattori, DDS, PhD/Mahmoud E. Elbashti, BDS, MSc, PhD/Yuka I. Sumita, DDS, PhD: Purpose: To assess the feasibility of using an intraoral scanner for data acquisition of maxillectomy defects. Materials and Methods: In 10 patients who had undergone a maxillectomy, the maxillectomy defects in dentate and edentulous maxillary arches were intraorally scanned. Intraoral photographs were also taken using a digital camera for comparison. Results: Adequate scanning was achieved for the nondefect side of the maxilla and for residual teeth. In some cases, it was impossible to scan the maxillectomy defect, especially the deep sites. Conclusion: Improved intraoral scanning technology will increase the feasibility of its use in maxillofacial prosthetics.

Subjective speech evaluation is important in maxillofacial rehabilitation. In previous research, the automatic speech intelligibility test system using monosyllables was developed using a computerized speech recognition technique, and it was suggested that the system may effectively be used in evaluated maxillectomy patients' speech. However the system showed some disadvantages such as the low sensitiveness for the mild speech disorders. In this study, the system was remodeled employing sentences as test stimuli to overcome the shortcomings. The new system was used to evaluate speech of normal adults and maxillectomy patients. The speech of 10 normal adults and 13 maxillectomy patients was evaluated using the automatic conversation intelligibility test system that employed sentences as test stimuli. Normal subjects repeated the test for three times on different days. The patients' utterances were examined in two conditions: with and without prostheses. The results from patients with and without prostheses were compared to each other, and also compared with their corresponding conversation intelligibility obtained using a perceptual method. In normal subjects, there was no significant difference in their scores using the automatic conversation intelligibility test on three different days. The result of the automatic test was significantly improved in patients by wearing prostheses. There were significant correlations between the result of the automatic test and the corresponding conversation intelligibility both in patients with prostheses and without prostheses. It was indicated that the automatic conversation intelligibility test system using sentences as stimuli would be effectively used in evaluating maxillectomy patients' speech.

The longevity of an extraoral prosthesis depends on its physical and mechanical properties and user maintenance. Faced with multiple outcome measures, researchers find it difficult to determine the most appropriate extraoral prosthetic material. This comprehensive review evaluates the most used extraoral prosthesis materials and qualitatively assesses their longevity and function. The study aims to identify and interpret the results of current updates on the factors that affect longevity and functionality. This comprehensive review summarizes and evaluates differences in the properties of commonly used extraoral maxillofacial prosthetic materials. The review was planned to focus on all factors related to the longevity and function of the extraoral maxillofacial prosthetics. An electronic search covered English articles in PubMed, Scopus, Google Scholar, Web of Science, and grey literature. Manual searching was also performed. Six authors participated in the screening. Search engines extracted 1107 records, and 88 studies were included for qualitative and bias assessments. Silicones are the most frequently used extraoral maxillofacial prosthetic materials. Heat-cured silicones are more color-stable than those cured at room temperature. Additional ingredients and processing techniques affect prosthesis longevity.

Oral cancer often requires treatments like surgical intervention, involving surgical resection of lips and other facial parts. For those patients, prosthetic rehabilitation following surgery promotes social reintegration. This study explores the color stability of various commercially available silicone materials for facial prostheses when exposed to everyday beverages like coffee and tea. The hypothesis is that these beverages can induce color changes in silicones, simulating conditions of daily use. A total of 90 specimens were fabricated. There were 30 specimens deefor each of 3 nonpigmented silicone elastomers: Silfy, A-2186-F and VST-50 and were immersed in tea or coffee at drinking temperature and evaluated for color changes at time points of 0 h, 1 h, and 6 h. The color was measured with a colorimeter that used the CIE L*a*b* system and the color change ΔΕ was calculated to quantify the color change. Statistical analysis was performed by using the Kruskal-Wallis test, the Mann-Whitney U test, and the Wilcoxon signed-rank Test. The threshold for statistical significance was P < .05. Color change was observed for each of the silicones exposed to the beverages (P < .05). The value of ΔE was significantly higher for A-2186-F compared with VST-50 and Silfy (P < .05 in all beverages at 6 h). The color of the elastomers progressively changed while immersed in the beverages over 6 h. The change in color was significantly greater for coffee compared with tea (P < .05). The color stability of nonpigmented silicone elastomers is inherently low, which contributes to the overall color change of silicone prostheses when they are exposed to beverages that contain pigments. The elastomer A-2186-F had greatest values of ΔE among the materials tested. Color changes of silicone prostheses can be lessened by selecting materials with consideration of color stability to improve their longevity and extend their period of use.