Bachhav, Aras pressions are made, these trays are reassembled - The assembly basically consists of 2 dual die- extraorally and are poured in dental stone to ob- pins and 2 sleeves. Closely juxtapose the 2 sleeves tain definitive, working casts. such that the smaller keyway of 1 sleeve faces Several studies have described various tech- the larger keyway of the other sleeve. Join these niques that are used for making custom sectional sleeves by inserting the 2 dual die-pins and mak- impression trays.14-18 Different devices used for ing the assembly a rigid joint (Figure 1a-d). connecting the custom sectional trays include - Make a slot on the inside portion of the han- hinges,14 plastic building blocks (Lego; Lego Sys- dles on each half of the sectioned custom trays to tems Inc, Enfield, Conn., USA),15,16 orthodontic ex- incorporate the sleeve (Figure 2a & b). pansion screws,17 or locking levers.18 - Attach the sleeves in the slots by using the This article describes a simple, cost-effective, autopolymerizing acrylic resin as mentioned pre- and time-saving method for fabricating custom viously (Figure 3). sectional impression trays using easily available - Verify the position of the attached sleeves by dual die-pins and sleeves as potential devices inserting die-pins such that the halves juxtapose for interlocking the sectional trays. The locking precisely in both the sectioned trays. mechanism design includes an anterior locking - Fabricate an anterior assembly for the man- assembly for the maxillary and mandibular cus- dibular sectional tray in a similar manner (Figure tom trays and a posterior locking assembly for 7). only the maxillary custom tray. 5) Steps in the fabrication of the posterior lock assembly in the maxillary custom sectional tray: TECHNIQUE - Cut the 2 dual die-pins that are attached to 1) By using the conventional method, fabricate sleeves halfway through their heights (Figure 4) by the maxillary and mandibular custom sectional using a carborundum disk (Dentorium, New York, impression trays by using autopolymerizing acryl- USA). Only the broader upper halves are used for ic resin (DPI-RR, Dental Products of India, Mum- fabricating the posterior assembly and the lower bai, India) on the preliminary casts. halves are discarded. 2) Make the handles of the trays (minimum di- - Attach the half-cut sleeves on the posterior mensions with 13 mm height, 10 mm length, and parts of the sectioned custom tray halves using 10 mm width) such that they incorporate the metal acrylic resin such that the greatest dimension of sleeves of the dual die-pins (M.R.TM Dual Pin and each sleeve is oriented in the anteroposterior di- sleeves, Select Dental). rection. Check for parallelism between the sleeves 3) Section both the custom impression trays using a dental surveyor and verify the fit of the die- at the midline by using a diamond disk (DFS, Ger- pins in the respective sleeves (Figure 5). many). - Fabricate an acrylic resin block (6 mm height, 4) Steps in the fabrication of the anterior lock 10 mm width, and 4 mm longer than the distance assembly in the maxillary and mandibular custom between the 2 attached sleeves) using the autopo- sectional impression trays: lymerizing acrylic resin (Figure 4). Figure 1. a-d. Basic design and components of anterior locking assembly for maxillary and mandibular sectional tray. a) Dual die-pins with sleeves, b) sleeves in approxi- mated position (Top view) and two dual die-pins, c) Dual die-pins inserted in contralateral direction making a rigid joint for anterior locking assembly (Top view), d) lateral view of anterior locking assembly. July 2012 - Vol.6 245 European Journal of Dentistry