DENT 165: LO3- Produce a Trimmed & Finished Stone Model

use of model trimmer

-to reduce & shape casts

-platform needs to be secured

-casts are held securely against the trimming wheel

-stream of water helps to eliminate dust & keep the wheel clean

-trimmer will cut faster if you apply light pressure against wheel

maintenance of model trimmer

-allow motor to run for 10-15 sec before turning off and water is running clear

-clean platform & trap after each use

-do not trim other materials other than stone (keep bite reg out of the way)

safety measures

-keep fingers away from wheel

-wear safety glasses, mask, gloves, ear protection, lab coat and close toed shoes

-long hair pulled back

trimming casts

-ensure all anatomy is present

-soak the casts in water for 5 min first

-remove any occlusal bumps or extensions of gypsum that prevents occlusion of casts

-do not remove anatomy

characteristics of the casts: study models

-before and after trimming

-size of the diagnostic cast

-anatomical portion

-art portion

what should we visualize when looking at the casts for a study model?

-2 parts: anatomical and art portions

study model: anatomical portion

-should comprise 2/3 of the cast

study model: art portion

-should comprise 1/3 of the cast

trim cast for mouthguard & whitening tray

-trim bottom of cast to the point where palate and base of stone is so thin that a hole is created

-trim the cast so that the mucobuccal fold is at the periphery of the cast

shape of diagnostic study casts

-anterior borders

-lateral borders

-posterior borders

-posterior corners

shape of diagnostic study casts: anterior borders

-symmetrical to the midline

-from canine to canine following the form of the arch, resulting in a rounded cut

shape of diagnostic study casts: lateral borders

-parallel to the posterior teeth

shape of diagnostic study casts: posterior corners

-parallel to the opposite cuspid or corner of mouth

shape of diagnostic study casts: posterior borders

-square with the midline

finishing stage of study models

-correcting imperfections

-fine trimming

-sanding

-polishing gloss/labelling (both casts)