Flexibility is our Strength Making Millions Smile™ Valplast® Flexible Partials Lab Techniques for Flexible Partial Dentures Introduction to Flexible Partials • Simple solution to provide a removable • • • • • • restoration No tooth preparation needed No metal frame needed Finished partial with one trip through the laboratory Injection Technique Valplast Partials are repairable and relinable Guaranteed not to break Type of Material • Valplast is a type of Nylon Thermoplastic • Injection Molded • Denser than acrylic • Lower Water Absorption than PMMA • Flexural modulus around 470MPa at body • temperature (making it both flexible and sturdy) In use since 1953 Lab Procedure - Overview • Design, block and relieve master model • Duplicate stone model • Try-in (if required) or Set-up on Master • Transfer set-up to duplicate model • Wax with prefabricated patterns • Invest, Sprue, Wax Elimination • Process with Manual Injector • Finish and Polish Visually Survey Model • Visualize design • Aesthetics • Path of Insertion • Comfort • Accuracy of Model Remove Discrepancies Wrap-Around Clasp • Most Common • • • Clasp Hugs Tissue Minimal Coverage of Tooth Stability against vertical and rotational movement Design is made with Red Pencil Split Wrap-Around • Clasp Separated from • • Flange Similar to “Roach” Clasp Flexibility along Horizontal and Vertical Axes Spur Anchor Maxillary Wax Relief • Relief Wax placed • along Buccal Periphery Necessary on All Maxillary Cases Use Hot Wax for Relief Mandibular Wax Relief • Junction of clasp with • saddle is more rigid area. Undercut toward periphery must be relieved Blocking and Relieving • Lingual Undercuts • • Relieved Interproximal Spaces Closed Obstructive Undercuts Removed Final Preparation • Beading Post Dam • Etching Design Duplication • Soak Model • Prepare Flask • Pour Gel • Let set 15 minutes • in air… …and 15 minutes in water Waxing After Setup • Use of Prefabricated Forms is Recommended to Insure Proper Thickness and Uniformity Palatal Waxing •Soften Palate •Press to Position •Seal all Borders Buccal Waxing Using Prefabricated Form: •Cut Form to Size •Press to Model •Seal all Borders Bottom Half Investing Spruing Top Half Investing Top Half Investing Teeth Prepared for Retention Processing Melting - 11 Minutes Injecting Let’s See That Again... After Processing Pre-Finishing EconoCutter Trimmer Dark Grinding Wheels Vulcanite Burs Fitting and Rubberizing Brown Rubber Wheels Polishing Polishing Motion is Important Advising Clinician on Insertion and Adjustment • Partial must be placed in very hot water (150°F or more) for a minute prior to insertion and allowed to cool to a tolerable temperature. • This process makes the partial as flexible as it would be at body temperature. This minimizes adjustments Adjustments • Minor clasp tightening or loosening can be done • • by heating the clasp again in very hot water and bending it severely in the needed direction. This will purposely warp the area enough to change its position Grinding should be done as a last resort. Use a Standard Green Mounted Stone (used usually for porcelain) to adjust Valplast. 20K to 30K rotation and constant motion Small Additions - Welding • Using hot air welder and welding rod, build up a • • • • boxing in the addition site to secure a new tooth Select a matching acrylic tooth. Break a porcelain tooth to obtain pins Heat each of two pins in flame to cherry red and embed in the partial half way (pin head protruding) Cure scooped stock tooth over pins using toothshade or pink acrylic. Large Additions – Injection • Wax new section on duplicate model to • • • original partial Invest, Sprue, Wash out wax Prepare bonding site with acid etch solution (Val-Fuse Repair Liquid) Inject, finish, and polish Relines • Take Putty Matrix to record tooth position • Strip teeth from partial (in blocks) while • • • duplicating the model. Rewax new base using matrix to position teeth Invest and process using repair technique to bond top-half exposed Valplast to new base. Finish and Polish Clinical Prep for Tooth Addition • Clinician should take overall alginate • • impression to lift out case Counter-model for bite Before pouring the model, any deposits or adhesives should be removed from surface or the process will lead to an unintended reline. Clinical Prep for Reline • Closed-mouth rubber-base reline • • impression. Pick-up overall alginate impression. Counter not necessary