Dental Occlusion Quiz 1

gypsum products types 1

impression and mounting palster

gypsum products type 2

model and laboratory plaster

gypsum product type 3

model and laboratory stone

gypsum product type 4

dental stone, high strength

gypsum product type 5

dental stone, high strength and high expansion

are type 1 and type 2 gypsum products stones or plasters

plasters

type 3-5 gypsum products are stones or plasters

stone

type 1 and type 2 are produced by

calcination- heating the raw materials to drive off part of crystal water and impurities

calcination rxn of type 1 and 2 dental plasters

gypsum dihydrate → open kettle, dry heat → calcined gypsum beta-hemihydrate form

characteristics of beta-calcium sulfate hemihydrate

irregular shaped particle, loose and porous white-powder, mounter plaster, model plaster

type 3 dental stones is produced by

calcination

calcination rxn of type 3 dental stones

gypsum dihydrate → autoclave, steam + pressure → calcined gypsum alpha-hemihydrate form

alpha-calcium sulfate hemihydrate characteristics

prismatic- shaped particle, dense white-powder, hard and strong products

type 4 and type 5 high strength stones rxn

dihydrate form → boiling in 30% CaCl2 and MgCl2 solution, wash w boiling water/dry/grind → modified alpha-calcium sulfate hemihydrate form

modified alpha-calcium sulfate hemihydrate characteristics

uniform-shaped particle (high in strength), denser powder, harder an stronger products

gypsum products vary in

water/powder ratio, working/setting time, dimensional accuracy, surface resistance and strength, reproduction detail

from type 1 going to type 5, how does the water:plaster change

as you go up in types of gypsum products- the ratio decreases so you need less water

as water:plaster increases, how does porosity % change

increases- more will form inside the final cast

setting time

the elapsed time from the beginning of mixing until the material hardens

after working time

the consistency of the mix is no longer acceptable for the product’s intended purpose, or the mixture fails to flow under manipulation or vibration

type 1 impression plaster edentulous ridge

polyether, alginate

type 1 mounting plaster characteristics

quick-setting, low-strength, low-expansion

type 3 mounting stone characteristics

fast-setting, high-strength, low-expansion

type 5 has increased expansion to compensate for…

shrinkage of vinyl polysiloxane and elastomeric impression materials

rank the gypsum products in order from highest to lowest working time

type 5 = type 4 > type 3-model/laboratory stone = type 2 > type 3- mounting stone > type 1

rank the gypsum products in order from highest to lowest setting time

type 5 > type 2 > type 3-model and laboratory stone > type 4 > type 3 mounting stone > type 1

rank the gypsum products in order from highest to lowest setting expansion

type 5 > type 2 > type 3- model/laboratory stone > type 4 = type 1 > type 3 mounting stone

which type of gypsum product would you use to make trimming full models, ditching dies, and scanning easier and more reliable… why?

UltiRock- ISO type 4 bc of it’s smooth non-reflective surface and is highly durable

which gypsum product is scannable where models can be used w CAD/CAM systems, eliminating the need for a specific scan stone or spray

LeanRock XL5- ISO Type 5

what should you do prior to pouring you water/powder ration in the bowl

rinse mixing bowl and shake out excess water

what gypsum products must you hand mix and is not recommended to use the vacuum mix

Type 1- mounting plaster and Type 3- mounting stone

what class does the semi adjustable articulator fall under

class 3

what are some characteristics of a semi adjustable articulator (5)

inc ability to reproduce mand movement, more accurate dimensions/accept face bow transfer or Kois sys, commonly used for occlusal analysis, fabrication for bridge fixed PD or CD, multiple units for prosthetics

what is reproducible in a semi adjustable articulators (5)

delayed side shift, horizontal condylar inclination, incisal guidance, protrusive movement, R/L lateral movements

what is non-reproducible in semi adjustable articulators (2)

inter condylar distance and immediate side shift

delayed side shift

during lateral translatory movement of the mandible, the condyle will move .5 mm laterally

what motion analogues are available in delayed side shift in a semi adjustable articulator

.5, 1.0, 1.5, 2.0, 2.5 mm

digital dentistry

use of dental technologies/devices that incorporates digital/computer-controlled components to carry out dental procedures rather than using mechanical or electrical tools

what do the input→ process→ output stages look like in digital dentistry

data acquisition→ design → manufacturing

analog workflow

process of performing a task using physical means and materials, usually carried out by hand as opposed to using digital technology

digital workflow

converting physical or “analog” structure into a digital format to be manipulated using CAD software

additive manufacturing

a process of joining materials to make objects from 3D model data, usually layer upon layer (3D printing)

digital light processing (DLP)

using a projector to cure liquid resin into solid objects layer by layer

lithography-based ceramic manufacturing (LCM)

polymerizes a ceramic powder suspended in a photosensitive resin, an LED light source projects into the resin, and through mask expose it selectively cures the resin and builds up the part layer-by-layer

CAD/CAM

Computer Aided Design & Computer Aided Manufacturing

CEREC

CEramic REConstruction

a semi-adjustable articulator w the condyle in the lower membrane is arcon or non-arcon

arcon

what kind of articulator do we use

semi-adjustable

the purpose of occlusal registrations strips is to

evaluate the amount of a contact