[Use of silicone template to prepare guide planes for removable partial denture]

Guide planes are used not only for one path of insertion and removal but also to increase both the stability of the denture and resistance to lateral movement; they also protect the abutments from displacement during insertion and removal of the denture. Therefore, it is necessary to give attention to this part of the mouth preparation in the construction of removable partial dentures. Some methods have developed to form exact guide planes. They are the free-hand method, the modeling plastic index, the acrylic index, the laboratory milling technique, and the intraoral parallelism device. However, most of these instruments are either too expensive or too sophisticated to be considered practical for removable partial denture preparations. This article describes a simple and effective method to assure the development of guide planes intraorally as they are planned on the diagnostic cast. The occlusal or incisal surface of the abutment on the prepared stone cast was completely covered with a newly mixed putty type silicone rubber base. The plastic silicone was put against the prepared guide plane on the stone cast and was compressed with a blockout trimmer held on the surveyor before the silicone setting. All of the prepared guide plane was contoured to disclose the marker and to form a ledge. After the silicone setting, the template was removed and trimmed so that soft tissue will not interfere with the intraoral reorientation. As the templates are placed on the abutments intraorally, the abutments bulging out of the template area are obviously discernible and prepared guide planes on the diagnostic cast can be easily and definitely duplicated on the abutments.