Dental Laboratory Techniques: Impressions, Casts, and Infection Control

Flashcards covering dental disinfection levels, impression pouring procedures, anatomical landmarks of the maxilla and mandible, and infection control protocols.

What are the three levels of disinfection based on the equipment's intended use and risk of infection?

High-Level Disinfection, Intermediate-Level Disinfection, and Low-Level Disinfection.

What characterizes High-Level Disinfection?

It kills all microorganisms except large numbers of bacterial spores and is used for semi-critical items like endoscopes.

Which level of disinfection is required for non-critical items contacting only intact skin, such as stethoscopes?

Low-Level Disinfection.

Within what timeframe must alginate impressions be poured after removal from the mouth?

$10-12$ minutes.

How should mucous film and debris be removed from the surface of an impression?

With a gentle stream of body-temperature water.

What type of separator is specifically mentioned for use when pouring one gypsum material against another?

Super-Sep.

What is the recommended uniform thickness for alginate material to prevent collapse?

$3\,mm$.

In fixed impressions, what is 'Dimensional stability'?

The property of an impression to maintain its shape after a period of time.

Why is elasticity important for modern final impression materials?

It allows the material to stretch as it is being removed from severe undercuts, facilitating easy separation.

Which anatomical landmarks are common to both the maxilla and the mandible?

The residual ridges, labial frenum, and buccal frenum.

What is the 'vibrating line' in the maxilla?

An imaginary line in the soft palate marking the junction between the movable and immovable tissues.

What is the hamular notch?

A deep depression located posterior to the maxillary tuberosity, formed by the junction of the pterygoid hamulus of the sphenoid bone and the maxilla.

Define the 'incisive papilla' in a maxillary cast.

A small pad of tissue located at the midline just behind the crest of the maxillary ridge which protects vessels and nerves exiting the incisive foramen.

What anatomical feature is found at the posterior extremity of the mandibular ridge?

The retromolar pad (or retromolar fossa in impressions).

Define 'Aerosolization' in a dental laboratory context.

Airborne particles caused by grinding or polishing, similar to the effect of spraying an aerosol can.

What is the definition of 'Sanitation'?

A process which removes gross debris and reduces the number of microorganisms on nonliving material.

How does 'Sterilization' differ from 'Disinfection'?

Sterilization destroys all forms of life, while disinfection destroys or inhibits most pathogenic bacteria but usually does not kill spores.

What are the six links in the chain of infection?

(1) Portal of entry, (2) susceptible host, (3) infectious agent, (4) reservoir, (5) portal of exit, and (6) mode of transmission.

How long can oral bacteria remain viable in set gypsum?

Up to $7$ days.

Why should alginate and polyether impressions be sprayed and sealed in a bag rather than immersed in disinfectant?

They will distort if immersed in solution.

Which impression materials can be totally immersed in disinfectant without distortion?

Polysulfide (rubber base) and polyvinyl siloxane (silicone) can be immersed in $2\%$ acidic glutaraldehyde.

What precautions should be taken when using an ultrasonic cleaner?

Keep it covered at all times to reduce aerosolization and change the solution when visibly dirty.

What are the specific requirements for laundering laboratory smocks?

Clean smocks should be worn daily; soiled smocks must be laundered separately from other apparel and NEVER at home.