Three-Dimensional Analysis of Donor Masks for Facial Transplantation.

BACKGROUND: Face transplant teams have an ethical responsibility to restore the donor's likeness after allograft procurement. This has been achieved with masks constructed from facial impressions and three-dimensional printing. The authors compare the accuracy of conventional impression and three-dimensional printing technology. METHODS: For three subjects, a three-dimensionally-printed mask was created using advanced three-dimensional imaging and PolyJet technology. Three silicone masks were made using an impression technique; a mold requiring direct contact with each subject's face was reinforced by plaster bands and filled with silicone. Digital models of the face and both masks of each subject were acquired with Vectra H1 Imaging or Artec scanners. Each digital mask model was overlaid onto its corresponding digital face model using a seven-landmark coregistration; part comparison was performed. The absolute deviation between each digital mask and digital face model was compared with the Mann-Whitney U test. RESULTS: The absolute deviation (in millimeters) of each digitally printed mask model relative to the digital face model was significantly smaller than that of the digital silicone mask model (subject 1, 0.61 versus 1.29, p < 0.001; subject 2, 2.59 versus 2.87, p < 0.001; subject 3, 1.77 versus 4.20, p < 0.001). Mean cost and production times were $720 and 40.2 hours for three-dimensionally printed masks, and $735 and 11 hours for silicone masks. CONCLUSIONS: Surface analysis shows that three-dimensionally-printed masks offer greater surface accuracy than silicone masks. Greater donor resemblance without additional risk to the allograft may make three-dimensionally-printed masks the superior choice for face transplant teams. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

Cost-effectiveness of silicone and alginate impressions for complete dentures.

OBJECTIVE: The aim of this study was to assess the cost effectiveness of silicone and alginate impressions for complete dentures. METHODS: Cost effectiveness analyses were undertaken alongside a UK single centre, double blind, controlled, crossover clinical trial. Taking the perspective of the healthcare sector, effectiveness is measured using the EuroQol (EQ-5D-3L) which provides a single index value for health status that may be combined with time to produce quality adjusted life years (QALYs); and Oral Health Impact Profile (OHIP-EDENT). Incremental cost effectiveness ratios are presented representing the additional cost per one unit gained. RESULTS: Mean cost was higher in the silicone impression group (£388.57 vs. £363.18). Negligible between-group differences were observed in QALY gains; the silicone group had greater mean OHIP-EDENT gains. The additional cost using silicone was £3.41 per change of one point in the OHIP-EDENT. CONCLUSIONS: The silicone group was more costly, driven by the cost of materials. Changes in the EQ-5D and QALY gains over time and between arms were not statistically significant. Change in OHIP-EDENT score showed greater improvement in the silicone group and the difference between arms was statistically significant. Given negligible QALY gains and low level of resource use, results must be treated with caution. It is difficult to make robust claims about the comparative cost-effectiveness. CLINICAL SIGNIFICANCE: Silicone impressions for complete dentures improve patients' quality of life (OHIP-EDENT score). The extra cost of silicone impressions is £30 per patient. Dentists, patients and health care funders need to consider the clinical and financial value of silicone impressions. Different patients, different dentists, different health funders will have individual perceptions and judgements. ISRCTN01528038. NIHR-RfPB grant PB-PG-0408-16300. This article forms part of a project for which the author (TPH) won the Senior Clinical Unilever Hatton Award of the International Assocation for Dental Research, Capetown, South Africa, June 2014.

Cost-effectiveness analysis of PMMA, silicone, or acrylic intra-ocular lenses in cataract surgery in four European countries.

PURPOSE: To compare the cost-effectiveness of different intra-ocular lens (IOL) materials (Hydrophobic acrylic, Polymethylmethacrylate (PMMA), Hydrophilic acrylic and Silicone) implanted after cataract surgery with reference to Nd:YAG laser capsulotomy and Nd:YAG-related complications in four European countries (France, Italy, Germany and Spain). SETTING: A retrospective review of 1,525 patients (eyes), aged 50 to 80 years, operated with phacoemulsification for cataract in 1996 or 1997 in 16 surgical centres (4 per country). METHODS: The study was conducted using a cost-effectiveness approach. Medical charts were reviewed to collect retrospective information during the 3-year period following cataract surgery in order to identify patients who underwent Nd:YAG laser capsulotomy post-operatively. Clinical data were combined with unit costs assessed by experts for Nd:YAG laser capsulotomy and their complications. A cost-effectiveness ratio (cost per patient without Nd:YAG laser capsulotomy intervention) was estimated in relation to each IOL material used in each of the four European countries. RESULTS: Hydrophobic acrylic, specifically Acrysof, was the most cost-effective IOL material in all the countries except Germany where it was second. PMMA had the best ratio in Germany, was second in Spain and only third in Italy and France. Silicone was second in France and ranked third in the other countries, while hydrophilic acrylic had the worst ratio overall in all countries. CONCLUSIONS: Cost-effectiveness ratios of hydrophobic acrylic (Acrysof) were better than those of other types of IOL materials used in most of the countries. Sensitivity analyses were performed to vary the base case analysis to demonstrate the economic importance of the assumptions. In all cases, hydrophobic acrylic IOL material was shown to be a highly cost-effective option.

A comparison of the cost effectiveness of pressure-indicating materials and their ability to detect pressure areas in complete dentures.

Pressure areas on the fitting surfaces of dentures can cause great discomfort and pain to denture wearers if not detected and removed. Pressure-indicating materials are commonly used to detect these areas, and several commercial varieties are available, but these tend to be expensive. The cost effectiveness of these materials has not been investigated, nor has this been linked to their efficacy and ease of use. The aim of this study therefore, was to compare the different pressure-indicating materials available commercially with that of a home-made paste. An assumption of efficacy was made by the number and size of pressure areas revealed, by taking standardised photographs and analysing the images. User friendliness was determined by the time taken to mix, apply and remove the material. Cost was determined by a cost per unit calculation based on the average or minimum quantity required for each material. The results indicated that a home-made paste made of equal quantities of hand lanolin (BP) and zinc oxide powder was not only the most effective, but was also the cheapest, being only 3% of the cost of the most expensive of the materials.

Low cost cosmetic hand prostheses.

66 patients with congenital or acquired amputations of the hand have been studied after fitting partial or complete silicone hand prostheses which can be manufactured at relatively low cost. Most patients used their prostheses on social occasions only and all but four expressed satisfaction with them.