PubMed1992
A wax tray is stable and easily relieved if overextended. Unusual tray undercuts or angles needed for the partial resection patient need not be eliminated before the impression procedure. Relief of these undercuts is necessary with acrylic resin trays to ensure separation from the final stone cast. Because the wax tray is separated easily from the prosthesis during the boil-out, it is not necessary to "burn" or grind acrylic resin from the framework. The tray shape is duplicated from the existing interim prosthesis on the nasopharyngeal and oropharyngeal side. An arbitrarily shaped acrylic resin tray may be grossly overextended and require time-consuming clinical adjustments. An underextended tray on the nasopharyngeal side will not carry or support the impression material around or through the residual soft palate remnant. A tray that closely approximates the final prosthesis will allow use of a tissue conditioner final impression without need for border molding (Fig. 2). Duplicating the oropharyngeal side of the interim speech aid duplicates the previously established plane that is compatible with the tongue. The author has used this technique successfully for eight total and five partial soft palate resections. A cleft palate speech aid prosthesis has also been made with this technique.