Toothwear 1

Question 1

physiological tooth wear

Answer 1

normal physiological process that increases with increasing age
approx 20-38um per annum

Question 2

pathological tooth wear

Answer 2

tooth wear occurs if remaining tooth structure or pulpal health is compromised or the rate is in excess of what it should be at that age
can also be pathological if pt experiences a masticatory or aesthetic deficit

Question 3

4 main causes of tooth wear

Answer 3

1. attrition
2. abrasion
3. erosion
4. abfraction

Question 4

attrition

Answer 4

physiological wearing away of tooth structure as a result of tooth to tooth contact

Question 5

signs of attrition

Answer 5

• found on occlusal & incisal contacting surfaces
• early appearance is a polished facet on a cusp or slight flattening of an incisal edge
• progression leads to reduction in cusp height & flattening of occlusal inclined planes
• can be shortening of clinical crown of incisor & canine teeth; more common anteriorly than posteriorly

Question 6

causes of attrition

Answer 6

almost always related to a parafunctional habit i.e. bruxism
flat facets are present
restorations show the same wear in this case as tooth structure

Question 7

abrasion

Answer 7

physical wear of tooth substance through an abnormal mechanical process independent of occlusion; it involved a foreign object or substance repeatedly contacting the tooth

Question 8

causes of abrasion

Answer 8

site & pattern related to abrasive element i.e. buccal / labial surfaces most common & related to toothbrushing, cervical on canine and premolar teeth
usually V shaped or rounded lesions
sharp margin at enamel edge where dentine is worn away preferentially
can manifest as notching of incisal edges
related to habit/lifestyle/occupation i.e. biting nails, electrical wire stripping, fishing line, thread, pipe smoking

Question 9

erosion

Answer 9

loss of tooth surface by a chemical process that does not involved bacterial action
it is the most common cause of pathological tooth wear and is increasing in prevalence

Question 10

causes of erosion

Answer 10

chronic exposure of dental hard tissues to acidic substances which can be extrinsic or intrinsic

Question 11

process of erosion

Answer 11

early stages enamel surface is affected with loss of surface detail, surfaces become flat & smooth
typically bilateral concave lesions without chalky appearance of bacterial acid decalcification
later dentine becomes exposed
preferantial wear of dentine leads to ‘cupping’ (dip in cusp tip) of occlusal surfaces of molars & incisal edges of anteriors
exact position & severity is dependent on source, type & frequency of acid exposure

Question 12

restorations & erosion

Answer 12

restorations are not affected as the tooth dissolves around the restoration so this is good to tell the difference between erosion & attrition

Question 13

appearance of erosion

Answer 13

increased translucency of incisal edges (can appear dark)
base of lesion not in contact with opposing tooth
amalgam & composite restorations stand proud of the tooth
no tooth staining present
maxillary & palatal are the most likely sites

Question 14

abfraction

Answer 14

loss of hard tissue from eccentric occlusal forces leading to compressive & tensile stresses at the cervical fulcrum areas of the tooth
happens in bridges

Question 15

causes of abfraction

Answer 15

pathological loss of tooth substance at cervical margin
caused by biomechanical loading forces
forces result in flexure & failure of enamel / dentine at a location away from the loading
disruption of the ordered crystalline structure of enamel and dentine by cyclic fatigue
this theory is based on engineering principles which demonstrates stress concentrations in these areas of the tooth during loading

Question 16

identifying abfraction

Answer 16

v shaped tooth loss where the tooth is under tension
classically sharp rim at the ACJ

Question 17

cervical wear

Answer 17

• probably multifactorial; overzealous tooth brushing
• lesions mainly in premolars & molars on buccal surface almost never lingually
• good OH & this wear pattern go together
• restorations in this area wear at same rate as tooth structure

Question 18

epidemiology of tooth wear

Answer 18

increases with increasing age
common type in older pt is physiological
increase in prevalence of all ages in last 10+ yrs
increase not uniform
greater relative increase amongst young adults & children and this tooth wear is considered pathological

Question 19

key questions to ask tooth wear case

Answer 19

1. is there aesthetic impairment
2. are there functional difficulties i.e. masticatory efficiency, biting of tongue or lips
3. pain; relatively uncommon unless it is rapidly progressing / pulpal involvement

Question 20

medical conditions that can influence tooth wear

Answer 20

particularly erosion
medication with low pH, medication that dries the mouth, eating disorders, alcoholism, heartburn, GORD, hiatus hernia, rumination, pregnancy, pt not always aware of reflux

Question 21

upon EO exam of pt

Answer 21

• examine TMJ for restriction of movement, clicking, crepitus
• examine musculature for hypertrophy
• examine mouth opening for restriction (<4cm) and deviation during movement
• parotid hypertrophy
• overclosure
• lip line & smile line

Question 22

examining pt occlusion

Answer 22

FWS should be assessed
record OVD & resting face height
has there been dento alveolar compensation
record OB / OJ
are there stable contacts in centric relation
what are tooth contacts like in excursive movements

Question 23

tooth wear index

Answer 23

0 - no loss of enamel surface characteristics
1 - loss of surface enamel characteristics
2 - buccal, lingual, occlusal loss of enamel exposing dentine for < 1/3 of surface, incisal loss of enamel, minimal dentine exposure
3 - buccal, lingual, occlusal loss of enamel exposing dentine for > 1/3 of surface, incisal loss of enamel, substantial dentine exposure
4 - buccal, lingual & occlusal complete loss of enamel, pulpal exposure or exposure of 2ndary dentine, incisal pulp exposure or exposure of 2ndary dentine

Question 24

BEWE

Answer 24

basic erosive wear examination
basically a BPE for erosive wear, recorded in sextants
0 - no erosive wear
1 - initial loss of surface texture
2 - distinct defect; hard tissue loss <50% of surface
3 - hard tissue loss >50% of surface
risk level:
none = <2
low = 3-8
medium = 9-13
high = 14+

Question 25

special tests used in tooth wear

Answer 25

sensibility testing
radiographs
articulated study models
intra oral photos
salivary analysis
diagnostic wax up
dietary analysis