CDT 8/9 - Restorative techniques for Class III, IV & V cavities

Question 1

class III cavity: what lining and bonding to use?

Answer 1

• calcium hydroxide if pulpal floor of cavity is deep
• vitrebond as main lining
• acid etching, dentine bonding agent

Question 2

class III cavity finishing: restoration can be contoured and smoothened with? what check must be done to ensure restoration will not fail?

Answer 2

• articulating paper

- check occlusion

Question 3

class V carious lesion: caused by?

Answer 3

poor OH
high, frequent carbohydrate intake
gingival recession (exposure, resulting in root caries)

other aetiology: abfraction, exaggerated levels of OH, erosion

Question 4

class V cavity:
what shape? how is shape dictated?
choice of material for restoration?
how to bring about retention? why?

Answer 4

• reniform, kidney shaped
• let caries dictate shape
• glass polyalkanoate, resin composite (moisture control!!)
• resin composite: acid etch and dentine bonding agent
• glass polyalkanoate: intrinsic ability to adhere to tooth, use of tooth cleanser maximizes chances of success

Question 5

glass polyalkanoate: set materials consist of?

Answer 5

• glass particles

- silaceous hydragel

Question 6

glass polyalkanoates: clinical application methods?

Answer 6

• cavity base
• restorative: class III and V, deciduous dentition, tx for root surface caries
• luting agent for fixed prostheses

Question 7

glass polyalkanoates: properties?

Answer 7

• adhesion to tooth substance
• tooth coloured and translucent
• fluoride release
• generally biocompatible
• brittle, poor abrasion resistance

Question 8

class IV - causes?

Answer 8

trauma:
sports,
class II occlusion - easier to get injured
small children,

Question 9

class IV restoration - technique and factors to note?

Answer 9

• acid etch, dentine bonding
• resin composite
• shade matching must be accurate

Question 10

shade matching: what must be ensured before shade selection?

Answer 10

• natural light, not operative light

- tooth must be hydrated

Question 11

what 8 factors to consider when selecting a shade? describe each factor

Answer 11

• hue: quality that distinguishes one color from another, 5 principle hues: red, blue, green, yellow, purple
• value: dimension that indicates lightness of color. 0 - pure black, 10 - white
• chroma: describes color intensity or saturation
• opacity: prevent passage of light
• translucency: allow light to be transmitted
• surface texture: rough surfaces reflect light in several directions, smooth surfaces rays are parallel to each other
• opalescence: scattering of short wavelengths
• lustre: gloss of an object