DT U.S. Edition, Nov./Dec. 2010, Vol. 5, No. 23

Adjustment-free appointments are actually possible and can be routine. Delivering veneers, inlays, onlays, crowns, bridges and partial dentures with very little or no proximal and occlusal adjustment can be common when a laboratory adheres to a strict protocol of die handling and die spac- ing, and has a firm understanding of cusp to fossa occlusion and anterior guidance. The laboratory must also possess a strong understanding of how to prop- erly equilibrate correctly mounted stone models and understand solid model verification. Basic cusp to fossa occlusion occurs when cusp inclines on posterior teeth do not touch other posterior inclines. Cusp tips must hit static stops in cen- tral fossa. In laboratory model equilibra- tion there is nothing more than the removal of all incline interferences and allowing cusp tips to occlude at 90-degree angles to opposing mar- ginal ridges and central fossa. Anterior guidance should allow complete free- dom from maximum intercuspation, immediately with lateral guidance on the canines. This will not activate the elevator muscles, therefore decreasing any chances of TMD. Equilibrating mounted casts is crucial to achieving adjustment-free delivery appointments. Less than 1 percent of technicians understand why we need to, much less, how to perform this task. Because of this, the following are common techniques used to try to achieve adjustment-free cementation appointments: • Placing metal foil under the work- ing die to create a space. If too much DENTAL TRIBUNE | Nov./Dec. 2010 Industry News 25A Laboratory communication Is it possible to achieve minimal to no adjustment bonding appointments? By Bob Clark, CDT, LVIM foil is used, the crown may be shy of occlusal contact. When that tooth does erupt into occlusion, it may work into an incline interference, creating an avoidance pattern for the mandible. • Pushing die up so crown appears out of occlusion on the model. After all, AD (Photo/Provided by Williams Dental Lab) g DT page 26A