ch. 1: dental materials

what are the 4 rationales for studying dental materials?

1. to understand the behavior of materials

2. to handle materials properly

3. to assess and treat the patient

4. to educate the patient

(view slideshow for specifics)

what is a biomaterial?

a man-made material used to replace tissues or function in close contact with living tissues

enamel is weak in its resistance to _______

bending

what structure of the tooth acts as cushioning for enamel and is more susceptible to acid attack?

dentin

what is the function of the periodontium?

provides feedback regarding forces placed on the tooth

• e.g. ow, im biting too hard

what three structures make up the periodontium?

PDL, cementum, alveolar bone

what is the function of gingival tissue?

seals out chemicals and microbes from gaining access to the periodontium and deeper tissues

what factors restrict the use of replacement materials in the mouth?

biting forces, degradation, temperature changes, biocompatibility, and esthetics

why are biting forces a concern with dental materials?

biting forces can fracture teeth or dental materials

what is an example of degradation of a dental material?

corrosion of metal

how do temperature changes affect dental materials?

they cause expansion and contraction

what does biocompatibility mean?

the material does not cause harm to the patient

why are esthetics important when choosing dental materials?

the material should have an acceptable/natural appearance

what is a herbst appliance used for?

a fixed orthodontic device used to correct a severe overbite (class II) by holding and guiding the lower jaw into a forward position

what is a palatal expander used for?

a custom orthodontic device that widens the upper jaw over time to create a better bite and make room for permanent teeth

what does the ADA Council on Scientific Affairs evaluate?

dental drugs, materials, instruments, and equipment

is submitting a product for ADA evaluation required?

no. it is a voluntary process

how long is the ADA Seal awarded for?

3 years

what are “specifications” for dental materials?

specific requirements for physical and mechanical properties measured in a laboratory

how does the FDA classify dental materials?

as medical devices

what is an FDA Class I dental device? give examples

least regulated; only good manufacturing practices are required

examples: prophy paste and brushes

what is an FDA Class II dental device? give examples

requires FDA approval and may be “grandfathered in”

examples: composites and amalgam.

what is an FDA Class III dental device? give an example

most regulated; requires FDA approval and premarket approval

example: bone grafts

what does the International Standards Organization (ISO) do?

attempts to unify standards among member countries

what does CE approval mean?

compliance with ISO standards

where is the CE symbol required for dental products to be sold?

european union markets

what are the three ways dental materials can be classified?

by use, location of fabrication, and longevity of use

how are restorations held in place?

by undercuts (mechanical retention), adhesion, or both

what is the difference between the walls of an inlay and an amalgam restoration?

an inlay has divergent walls, while an amalgam has convergent walls

what are cements used for?

used for luting objects together

what are bases and liners used for?

help protect the pulp from irritating materials, such as acids

examples of preventive materials

• pit and fissure sealants

• mouth guards

• fluoride trays

what are direct restorative materials?

materials constructed directly in the oral cavity that are initially putty-like and set to become hard

what are the three examples of direct restorative materials?

amalgam, composites, and glass ionomers

how does amalgam form/set?

liquid mercury is combined with powdered materials

how do composites set?

they polymerize through a specific chemical reaction

how do glass ionomers and other cements set?

through an acid-base chemical reaction

what is Ketac?

a glass ionomer dental material that releases fluoride

what are indirect restorative materials?

materials fabricated outside the mouth on a replica of the patient’s oral tissues

what are examples of indirect restorative materials?

gold crowns, bridges, onlays, inlays, porcelain crowns, PFM crowns, and indirect restorative polymers

what is an interim restoration?

a long-term temporary restoration

how long are temporary restorations usually used?

6-12 months

are permanent restorations actually permanent?

no, all restorations eventually wear out

class I caries

all pit and fissure restorations

class II caries

cavities in proximal surfaces of premolars and molars

class III caries

cavities in proximal surfaces of incisors and canines

class IV caries

cavities in proximal surfaces of incisors and canines that do involve the incisal edge

class V caries

cavities on the cervical third of facial or lingual surfaces

class VI caries

cavities on incisal edges of anterior teeth and cusp tips of posterior teeth