Clinical Protocol for Removable Partial Dentures

Diagnosis & Treatment Planning Gather diagnostic info Make preliminary impressions Pour diagnostic casts

Mounting Diagnostic Casts If required: Extruded teeth Severe attrition Insufficient interarch space Deep overbite, etc. use Semiadjustable Articulator

Formulate Treatment Plan Overall Treatment Plan Specific RPD Treatment Plan Select abutments, direct retainers Major connectors Position of rests, g.p., bracing & retentive arms

Critical!!! When RPD is part of treatment: Draw design on surveyed cast Design approved before any treatment started: Affects direct restorations Can influence need for/preparations for crowns Insures RPD can be completed successfully Survey, tripod, heights of contour

Formulate Treatment Plan Discuss with instructor prior to discussing with patient Provide rationale for design

Final Impressions for Partial Dentures Framework Impression Altered Cast Impression

Framework Impression Border Molded Custom Tray Tray that is made for patient Mold tray periphery with thermoplastic compound

Framework Impression Material of Choice Polyvinyl Siloxane

Framework Impression Polyvinyl siloxanes Excellent dimensional stability Good tear strength No taste Glove contamination Relatively hydrophobic - improved

Prior to the Final Impression No plaque or calculus Healthy soft tissues Initial therapy complete

Prior to the Final Impression Make alginate impression to check: Guiding planes Rest seats Retentive areas Heights of contour

Framework Impression Syringe low viscosity material Around abutment teeth Over occlusal surfaces Use care in rest seats Do not over fill trays - overextension

Framework Impression Medium viscosity in tray Increased filler content less shrinkage Less displacement of soft tissues than high viscosities

Evaluating the Impression Absence of Significant Voids Any area where metal contacts abutment (e.g. rests, minor connectors) Any area where major or minor connectors contact soft tissue

Evaluating the Impression Peripheries well defined Accurately records supporting tissues Allows for all elements of design

Evaluating the Impression Mandible Measure FGM to floor of mouth Record measurements Transfer to cast - inferior framework border

Evaluating the Impression No significant areas “burn-through” Border molding not covered Displaces the tissue Change in contour caused by the border molding

Evaluating the Impression Impression integrity No significant tears Not separated from tray

Evaluating the Impression Impression integrity No significant tears Not separated from tray

Evaluating the Impression Critical Anatomy Recorded Vestibular depths Hamular notches (marked) Vibrating line (marked) Retromolar pads Frenal attachments Floor of mouth (measured)

Preparation for Impression Practice inserting & removing tray Dry tissues

Preparation for Impression Block out large embrasures bridge pontics Don’t cover occlusion or framework surfaces

Preparation for Impression Teeth must be DRY for wax to stick

Don’t Reseat Impression Won’t fully seat over undercuts

Framework Impression Box & pour impression SINGLE POUR for master casts Survey & tripodize Draw design Send to Lab with Work Authorization for framework fabrication

Master Cast Pour in improved dental stone Type IV (Silky Rock) Vacuum mix stone Allow to set at least 1 hour strength to resist fracture

Master Casts No significant bubbles or flaws Teeth not fractured from cast Includes all anatomical surfaces of final impressions Includes 3-4 mm. land area

Master Cast Base parallel ridge 12 mm (.5”) thick (minimum) Evidence of a dense stone surface Clean & well trimmed (keep wet while trimming)

Fabricate Second Cast Draw design on secondary cast Checked/corrected with instructor Correct design on 2nd cast Send to lab with 1st poured cast lab will transfer the design to this cast

RPD Protocol Summary Diagnosis, Treatment Plan, Hygiene Diagnostic Casts Draw Design & list abutment modifications Instructor Approval Abutment modifications Preliminary impression to check mod.’s Final Framework Impression Pour two casts

RPD Protocol Summary Draw design on 2nd cast Instructor approval/corrections Cast to Lab with 1st pour & prescription Inspect framework waxup Framework Adjustment Altered Cast impression, if needed Try-in with teeth in wax Process, deliver to patient