Restorative Flashcards
What are the causes of tooth surface loss?
Caries
Trauma
Developmental problems
Toothwear
What is the definition of tooth wear?
A normal physiological process that increases with increasing age
What is the definition of physiological tooth wear?
Normal wear associated with function
What is the estimated normal toothwear per year?
20-38 um
What is the definition of pathological tooth wear?
Occurs if the remaining tooth structure or pulpal health is compromised
The rate of tooth wear is excessive to the patients age
The patient may experience a masticatory or aesthetic deficit
What are the causes of tooth wear?
Attrition
Abrasion
Erosion
Abfraction
What is the definition of attrition?
The physiological wearing away of tooth structure as a result of tooth to tooth contact
Where are attritive lesions found?
On the occlusal and incisal contacting surfaces
What is the early appearance of attritive toothwear?
Polished facet on a cusp or slight flattening of an incisal edge
What does the progression of attritive toothwear lead to?
Reduction in cusp height
Flattening of occlusal inclined planes
Shortening of the clinical crown of the incisor and canine teeth
What habit is attrition associated with?
Bruxism
What is the definition of abrasion?
Then physical wear of tooth substance through abnormal mechanical process independent of occlusion.
Involves a foreign object or substance repeatedly contacting the tooth
What are the features of abrasion?
Site and pattern associated to the abrasive element
Labial/buccal, cervical on canine and premolar teeth
V shaped or rounded lesions
What is a common cause of abrasion?
Toothbrushing
What is the definition of erosion?
The loss of tooth surface by a chemical process that does not involve bacterial action
What are the features of early stage erosion?
Enamel surface affected
Loss of surface detail
Surfaces become flat and smooth
Bilateral, concave lesions without chalky appearance of bacterial acid decalcification
What are the features of later stage erosion?
Dentine becomes exposed
Preferential wear of dentine leads to ‘cupping’ of the molar surface and incisal edges of molars
What is the positioning and severity of erosive wear dependent on?
Source, frequency, and type of exposure to acid
What are the features of erosion?
Increased translucency of incisal edges (can appear dark)
Base of lesion not in contact with opposing teeth
Amalgam and composite restorations stand proud of the tooth
No tooth staining
What is the definition of abfraction?
The loss of hard tissue from eccentric occlusal forces leading to compressive and tensile stresses at the cervical fulcrum areas of the tooth
What are the two theories of abfraction?
- Abfraction is the basic cause of all non-carious cervical lesions
- Multifactorial aetiology; a combination of occlusal stress, abrasion and erosion
What are the causes of abfraction?
Caused by biomechanical loading forces that result in flexure and failure of enamel and dentine at a location away from loading
What is the impact of mechanical loading on enamel crystals (abfraction)?
Disruption of the ordered crystalline structure of the enamel and dentine by cyclic fatigue
What are the causes of cervical wear?
Multifactorial; tooth brushing