Non-Carious Hard Tissue Loss

Question 1

6 causes of non-carious/ perio tooth loss and define

Answer 1

• attrition: tooth to tooth frictional wear
• abrasion: physical wear other than by tooth
• erosion: chemical non-bacterial dissolution (acid)
• abfraction: tensile/ shear stresses weakening enamel prisms (micro-fractures)
• resorption (roots)

Question 2

critical pH. what happens below

Answer 2

5.5

below this, tooth erodes, lose enamel prisms

Question 3

when does tooth wear become significant 3

Answer 3

when it causes problems with

• function
• aesthetics
• sensitivity

Question 4

% population with

a. tooth wear
b. pathological tooth wear

Answer 4

a. tooth wear: 97%

b. pathological tooth wear : 7%

Question 5

2 classifications of erosion

Answer 5

• extrinsic: exogenous acids (occupation, diet)

intrinsic: endogenous acids (GI)

Question 6

examples of dietary factors that cause erosion

Answer 6

• drinks: smoothies, herbal tea, sports drinks, wine, juice, coke
• food: citrus fruit, pickles, yoghurt, salad dressing, vinegar, indian food
• medicaments: lemsip, vit C, iron tonics, aspiriin, mouthwash

Question 7

lifestyle factors that cause erosion

Answer 7

• industrial: acid fumes
• wine tasters
• swimmers in chlorinated pools
• sportsment (acidic drinks)

Question 8

5 factors that influence impact of extrinsic erosion

Answer 8

• frequency
• pH/ buffering capacity
• method of consumption (eg swishing worse than straw)
• time (night-time worse)
• temperature (worse with heat eg herbal teas, lemsip)

Question 9

relationship between non-carious tooth loss factors

Answer 9

non-proportional: >1 factor causes a lot more damage

Question 10

development of taste buds and relevance

Answer 10

children don’t have taste buds until they are exposed to those stimuli –> if they are never given sweets, they won’t want them

Question 11

compare deciduous and permanent teeth terms of erosion/ caries susceptibility

Answer 11

deciduous: enamel more porous, thinner, less mineralised –> more susceptible to caries and erosion

Question 12

causes of intrinsic erosion

Answer 12

• GORD
• pregnancy
• diabetes
• neurological, psychosomatic and CNS disorders eg bolemia

Question 13

prevalence of GORD

Answer 13

7%

Question 14

causes of GORD

Answer 14

chronic alcoholism, GI ulcers, hiatus hernia

Question 15

prevalence of eating disorders in females

Answer 15

0.5%

Question 16

prevalence of alcoholism in genders

Answer 16

M: 1/5
F: 1/8

Question 17

explain voluntary regurgitation

Answer 17

‘chewing the cud’
vomit in to mouth, chew and swallow again
common in stress, cerebral palsy, institutionalised

Question 18

effect of pregnancy on vomiting

Answer 18

1st trimester- morning sickness

3rd trimester: regurgitation

Question 19

likely cause of erosion

a. anterior teeth external/incisal
b. posterior teeth occlusal
c. palatal surface

Answer 19

a. anterior teeth external/incisal: acidic fruits
b. posterior teeth occlusal: acidic drinks
c. palatal surface: intrinsic (vomiting)

Question 20

common sites for attrition

Answer 20

• proximal contacts points during function
• supporting cusp tips during grinding
• guiding surfaces during grinding

Question 21

freq of attrition needed to be noticable

Answer 21

heavy forces >35 mins/24 hours (remember mosst grinding occurs at night during sleep)

Question 22

is pathology more freq in attrition or erosion

Answer 22

erosion

Question 23

% population affected by bruxism

Answer 23

up to 96%

Question 24

% of normal biting force when grinding

Answer 24

30-60%

Question 25

causes of bruxism

Answer 25

• anxiety/ stress

- ecstacy, MD, meth (gurning)

Question 26

do people with attrition have canine or group function and why

Answer 26

group function. canines worn down by attrition

Question 27

attrition or erosion what causes

a. enamel and dentine wearing at equal rate
b. proud restorations
c. tooth mobility
d. cupping of molars
e. more breakdown of enamel than dentine

Answer 27

a. enamel and dentine wearing at equal rate: attrition
b. proud restorations: erosion
c. tooth mobility: attrition
d. cupping of molars: erosion
e. more breakdown of enamel than dentine: erosion

Question 28

risk factors for abrasion

Answer 28

occupational eg hairdressers (hairpins in mouth)
carpet layers (carpet in mouth) etc
-too hard tooth brushing 
-flossing incorrectly 
-porcelain crowns

Question 29

most common sites for abrasion

Answer 29

buccal/labial surface of incisors, canines, premolars

Question 30

physiological amount of enamel wear/yr

Answer 30

20-40 microns/yr

Question 31

impact on abrasion:

a. gold
b. amalgam
c. porcelain
d. NiCr
e. acrylic
f. composites

Answer 31

a. gold: least abrasion
b. amalgam: ok
c. porcelain: v bad, lots of abrasion
d. NiCr: more abrasive than enamel
e. acrylic: less abrasive than enamel
f. composites: depends on filler size (larger filler = better aesthetics but more abrasive)

Question 32

explain abfraction

Answer 32

occlusal loads –> cusps FLEX (esp premolars) –> deform enamel at cervical margin –> enamel pings off

Question 33

difference in appearance between adfraction and abrasion cavities

Answer 33

abfraction cavities deeper, more defined notch

Question 34

3 causes of root resorption

Answer 34

• developmental (deciduous teeth during exfoliation)
• pathological (dentigenerous cysts, space-occupying lesions)
• idiopathic (eg following trauma/ infection)

Question 35

effect on roots of

a. benign lesion
b. malignant lesion

Answer 35

a. benign lesion: pushes roots apart. tooth stays vital

b. malignant lesion: eats in to roots, –> non vital tooth

Question 36

3 types of resorption

Answer 36

• external inflammatory resorption: TTP, discolouration, mobility
• external surface resorption: usually apical after trauma/ ortho/ re-implantation
• internal resorption: pink spot, starts at pulp and moves outwards. cervical 1/3. usually asymptommatic