Lab procedures part 1 - Steve Pigliacelli.pdf

New York University College of Dentistry 345 East 24th street New York, NY 10010 LABORATORY COURSE FOR FIRST-YEAR STUDENTS Part 1 Adjunct Instructor Prosthodontics Steven Pigliacelli, MDT, CDT Steven Pigliacelli, MDT, CDT Laboratory Technology Lecture: Observe all stages of the crown and bridge...

New York University College of Dentistry 345 East 24th street New York, NY 10010 LABORATORY COURSE FOR FIRST-YEAR STUDENTS Part 1 Adjunct Instructor Prosthodontics Steven Pigliacelli, MDT, CDT Steven Pigliacelli, MDT, CDT Laboratory Technology Lecture: Observe all stages of the crown and bridge department for waxup procedures. a. Dental Biomaterial Science b. Biocompatibility of Dental Materials used in the Industry c. Preparatory Procedures a. Pour dies and models b. Pindex c. Setting bites d. Articulation d. Die trimming a. Die marking, block out, die spacer etc. e. Waxing copings a. Waxing full occlusion b. Sprue techniques f. Casting a. Finish copings b. Solder connections c. Cut back for ceramics Dies from the Impression The information the lab requires from the dentists is • • • • • • • • • • • • Neat handwriting Legible descriptive prescriptions Time Shades and models Alloy specification Margin design Pontic design Articulations Correct tooth numbers Implant manufacturer Prescription details Contact information Digital Prescriptions • Simplified system where simple check marks fill the Rx • No sloppy handwriting • Reconciles charts with lab and billing Coefficiency of Expansion https://nyu.app.box.com/file/677634536446?sb=/activity/versions/719181316846 Chapter-15---Dental-and-Orofacial-Impl_2012_Craig-s-Restorative-Dental-Mater Accuracy of material used. Plastic graduate. Mass produced. Comes free with the box. Glass graduate. Most precise Master cast material should be properly mixed by manufacturers specification Proper liquid to powder ratio for proper expansion Chapter-12---Replicating-Materials-Impressi_2012_Craig-s-Restorative-Dental In order for the lab to be able to maintain the vertical and centric of a full arch reconstruction, please use a Stratos, Artex, Hanau (or equivalent articulator) or a front pin hinge articulator (see figure #1). A plain hinge articulator without a front pin cannot maintain the vertical. The rear screw can easily be loosened and close the vertical. The front pin is a vertical stop that will allow the technician to remove the teeth from the mounted model and reset new teeth onto the model and not lose centric. Furthermore, the 1/4 rim is designed to act as a seat for the stone index to rest on. The indexes should not extend to model sides. (See figure 3). The one exception being the use of a rubber index. which is flexible Dies from Impression Full contour wax up Cut back for ceramic alloy Pontic Design: It is very important to specify the desired pontic ridge design. Below are examples of each design. Sanitary Sanitary Design for a cleansable solution. It does not touch the ridge. It is also known as a Hygienic Pontic. Full Ridge Full Ridge Design is more for esthetics and harder to maintain and keep clean. Modified Ridge Lap Modified Ridge Lap is for esthetics but easier to maintain and keep clean then the Full Ridge Lap. Bullet Bullet design just touches the ridge and is cleansable like the Sanitary Design. Sprue for lost wax casting technique Clean the wax pattern Proper placement in casting ring Must be out of heat zone for proper casting…… …so no porosities will occur in casting of alloy Proper powder liquid ratio and vacuum mixer Pour Investment into ring, make sure to avoid trapping air Proper bench set time and base removal Proper coefficient with ringless system What is the proper alloy ? ADA approved materials Semi-Precious Noble Silver-Palladium SP Precious High Noble White Ceramic Gold WG Precious High Noble Yellow Ceramic Gold Non-Precious Base Alloy NP Precious High Noble 60 Gold Precious High Noble B Gold Medium e.max Lithium Disilicate Procera Zirconia Proper heat rate and temperature in casting oven Proper gas to oxygen ratio for casting Heat alloy in crucible centrifuge Melt alloy without trapping gasses Do not place torch to close to alloy to avoid burning and porosities Proper melted alloy mix Centrifugal force Lost wax technique metal where wax used to be Cutting off the casting Remove the sprues Must use proper stones to finish the copings to avoid contamination Fit on the cast without breaking the dies Evaluate quality of the casting Pits and porosity Metal try in Solder pick up with resin connection Reinforced master solder model Master cast Pre-soldered crowns on the cast Reinforced resin cast without the frame in place Use the acrylic bite plate Steven Pigliacelli MDT, CDT [email protected]