6. Tooth wear I Flashcards
1
Q
LOS
A
2
Q
What is tooth wear?
A
- cumulative surface loss of mineralized tooth substance due to physical or chemo- physical processes (dental erosion, attrition, abrasion).
- NOT CONSIDERED TO BE AS A RESULT OF CARIES, RESORPTION OR TRAUMA
3
Q
what is erosive tooth wear?
A
tooth wear with dental erosion as primary etiological factor
4
Q
diff between tooth wear + erosive tooth wear?
A
5
Q
TIP
A
- if you see severe tooth wear always look for the acid causing it, especially if the patient is young
6
Q
What is abfraction?
A
- This is a non-carious tooth tissue loss that occurs along the gingival margin
- It is a mechanical loss of tooth structure that is not caused by tooth decay, located along the gum
line - Poor evidence base that occlusal forces cause tooth wear
- Good evidence base that occlusal equilibration is ineffective
- No fractures detected under Scanning Electron Microscopy or Confocal Laser Scanning Microscopy
- Abrasion scars detected in 70-100% of lesions
7
Q
prevalence of tooth wear in adults?
1
UK
2
Europe
A
1
- 77% of dentate patients have tooth wear into dentine in their anterior teeth
- 15% showed moderate wear
- 2% showed severe wear
(UK dental health survey 2009)
2
- Roughly 1/3 of all European adults aged 18-35% have one surface with moderate tooth wear
- 3% have severe tooth wear
8
Q
prevalence of tooth wear in children?
A
- 1,308 children were examined in Birmingham at the age of 12years and re-examined 2years later
- New or more advanced lesions were seen in 27% of the children over the study period
- 12% of erosion-free children at 12years had developed the condition over the 2years period
- severe tooth wear can be sign of acid reflux or due to diet
- important to start prevention education early
9
Q
why is the prevalence of tooth wear increasing?
A
- fruits are available out of season
- more snacking throughout the say
- more soft drinks consumed
- flavourings in water
10
Q
recap on enamel composition + structure?
A
- Enamel is one of the hardest structures in the human body
- roughly 96% mineral content in the form of substituted calcium hydroxyapatite, 3% water and 1% organic tissue
(weak against acids due to high mineral content) - On tooth eruption, outside layer of enamel, is a relatively disorganised structure, containing no prisms and hence is called the ‘aprismatic layer’ which is up to 100 microns deep
- has the highest mineral content, containing fluoride and phosphate in the form of fluorohydroxyapatite
- This layer has been shown to offer the greatest protection against both acid and mechanical challenges as it doesn’t have a prism structure
- Hydroxyapatite crystals are arranged in key-hole shaped prism structures which run perpendicular to the outermost layer of enamel
(as prisms, shaped like tube so acid can run down + cause a little bit of subsurface softening)
11
Q
recap on dentine composition and structure
A
- Dentine is a permeable structure composed of 75% mineral, 20% organic material and 5% water
- Closest to enamel is the mantle dentine = roughly 15–30µm thick
- Mantle dentine = similar to the aprismatic layer in enamel, is disorganised and only has a few thin, curved tubules
- bulk of dentine consists of intertubular dentine, a type I collagen-rich structure
- This collagen network is moisture rich and elastic resulting in reduced hardness and higher susceptibility to mechanical wear, such as abrasion + attrition
(thus more likely to wear than enamel) - Peritubular dentin is formed within the lumen of the tubules
- It is formed by a network of proteins and apatite crystals with no collagen fibrils
- Peritubular dentin is highly mineralised making it more susceptible to an acid challenge
- as if loose peritubular dentin then tubule is widened hence more susceptible to acid challenge + hypersensitivity)
12
Q
Pathophysiology of teeth
A
- When teeth are exposed to an acidic environment, minerals are released from the surface causing softening of the outermost layer between 0.2 and 2µm thick
- When acid encounters a natural enamel surface, there is initial breakdown of the interface between the prism and interprismatic layer widening the prism (12)
- Thereafter, the prism cores are richer in carbonate, making them more susceptible to erosion
- Liquid can move through enamel prisms of the teeth causing subsurface softening
- In the absence of further erosive challenges or mechanical removal, there is possibility for minerals to form new ionic bonds in the acid softened enamel
- BUT this needs to be in very early stages of enamel
13
Q
chemistry of dental erosion VS caries
A
CARIES
- Initial lesion has a small surface area
- Generally in protected areas with potential for localised application of remineralising agents
- Deep lesions
- Outer surface is generally harder due to fluoridation
- Increased oral hygiene results in decreased disease progression
EROSION
- Initial lesion has a large surface area
- No protection from environment when demineralised
- Wide shallow lesions
- Outer surface is softest
- Increased oral hygiene may result in increased disease progression
14
Q
summary of what happens during mild acid challenges?
A
- acid causes outflow of minerals
- this leaves behind a softened surface which is more at risk to physical forces eg. brushing
- fluoride + calcium ions can be incorporated back into tooth structure, rehardening it + making it less susceptible to future acid challenges
- Enamel is very mineralised so is strong in absence of acid challenge, mechanical wear needs high aggression to remove
- Dentine however is much easier to remove with mechanical wear, even without acid although this increases rate
15
Q
how does tooth brushing affect tooth wear?
A
- Toothbrushing with a force of 400g (normal brushing force is 100-300g), has been shown to remove dentine and increase the number of patent dentine tubules.
- Attritional forces have the capacity to remove exposed dentine. This is worse on acid softened dentine
16
Q
ACID EROSION VS DENTAL CARIES features
A
EROSIVE TOOTH WEAR
- Involves “softening” of surface enamel
- Acids are relatively strong
- Occurs on plaque-free surfaces
- HCl (intrinsic, gastric origin) and citric acid (extrinsic, dietary origin) are main acids involved
- Outer surface is softest
- Involves a widespread shallow unprotected area
- Brushing can exacerbate erosive tooth wear
CARIES
- Involves subsurface demineralization
- Acids are relatively weak
- Plaque is a prerequisite
- Outer surface is generally harder due to fluoridation
- Involves a localized deep protected area
- Brushing will often improve caries
For both it is important to find all of the risk factors, examine the diet and examine oral hygiene
17
Q
How might tooth wear present?
A
- short teeth
- dips/ crevices in teeth
- teeth keep chipping
- flat teeth
- sensitive teeth
- gums shrinking away (usu non-carious cervical regions wear they’re brushing the teeth away)
- grind teeth
- wake up with pain
18
Q
key features to look out for for tooth wear?
A
- Early identification is key
- key teeth to watch = maxillary central incisors and the lower first molars
- Usually clean, plaque free surfaces
- early stages can be difficult to distinguish with unworn teeth
- as lesions progress, it becomes easier to identify, but tooth wear will be worse
19
Q
anterior teeth - what to look for in early erosion tooth wear?
A
- Loss of enamel surface anatomy produces rounding of mesial and distal edges and along the incisal edge
- Loss of perikymata, mamellons and pronounced cingulum features
- A glassy smooth appearance on the facial/buccal surfaces
20
Q
anterior teeth - what to look for in moderate erosion tooth wear?
A
- Loss of palatal tooth structure reduces support along the incisal edge
- The tooth becomes shorter
- Distinct buccal lesions can also occur and grow in size
- As the condition progresses the lack of support leads to fracture of the enamel
21
Q
Severe ETW: Anterior teeth features
A
- Technically classified as severe erosive tooth wear
- prevention is still effective and a focus and can stop the restorative cycle
- Easy to spot some exposed dentine
but some may be largely enamel - Rehab of teeth are quite difficult
- As it progresses Darkening from underlying dentine
- grooving/ wear along incisal edge
- shortening of clinical crowns
22
Q
very severe ETW: Anterior teeth features
A
- really hard to restore
- patients biting in wrong areas
23
Q
Early ETW: Posterior Teeth features?
A
- Rounding of cusp tips
- Loss of morphology such as distinct ridges, deep fissures
- Surfaces become shiny and glossy
- loss of staining
24
Q
Moderate ETW: Posterior teeth features?
A
- Cupping on occlusal surfaces
- Increasing exposure of “yellow” dentine
- Changes to the shape of teeth
- Shortening of the clinical crowns
- cupped out lesions indicate acids - either from stomach or diet
25
Severe ETW: Posterior Teeth features
- Lesions start to merge
- Extensive dentine exposure
- Shortened clinical crowns
- Occlusal changes with alveolar compensation
- Prevention may slow progression and avoid the restorative/maintenance cycle
- no restorative space
- very very difficult to restore
26
what is BEWE?
- basic erosive wear exam
- simple tool to use alongside the BPE
- Designed as a screening tool to alert the practitioner and the patient
- Quick and efficient
- The name indicates the role – grade all tooth wear not purely erosion
- Does not indicate need for restorative intervention
27
Performing the BEWE?
- Divide patient’s dentition into sextants
- Assign a BEWE score to the tooth area in each sextant most severely affected by erosive tooth wear
- calculate your patient’s cumulative score
28
What are BEWE scores?
_always go for the worst surface in that sextant
0
- no erosive tooth wear
- patients over 30 usu don't score zero
1
- Initial loss of (enamel) surface structure
- no distinct defect
- but definite signs of erosive tooth wear happening
2
- Distinct defect forming, hard tissue loss of <50% of the tooth surface area
3
- Hard tissue loss of >50% of the surface area (dentine may be visible)
29
How to decide BEWE score?
30
how to calculate patients cumulative score?
- a 3 in a sextant = high risk
- Using the diagram assign and calculate your patient’s total score across sextants
- Low: 6 or lower
~ Oral hygiene, dietary assessment
~ Routine maintenance and observation
~ Repeat at 2-year intervals
- Medium: 7-12
~ Oral hygiene, dietary assessment
~ Routine maintenance
~ Fluoride measures
~ Avoid restorations
~ Repeat at 3-6 month intervals
- High: 13 or over
~ As above with the exception of the
following:
~ Consider restorations
31
Can you use BEWE for children
Children VS adult tooth wear rate?
- The BEWE can be used for children
- Use risk assessment on highest BEWE score in a sextant
- The primary dentition wears at a faster rate than the permanent dentition
Key message: you are documenting their wear status in the notes and informing the patient or patient’s carers
32
Example BEWE
- if not sure of score always score down, NOT up
33
how to use risk levels as a guide to clinical management?
0-2 No Risk (Primary prevention)
* Routine maintenance
* Repeat 3 year intervals
3-8 Low Risk (Primary Prevention)
* Oral hygiene, dietary assessment
* Routine maintenance
* Review 2 years
9-13 Moderate risk (Secondary prevention)
* Oral hygiene, dietary assessment
* Routine maintenance
* Fluoride measures
* Consider direct restorations (sealant restorations, direct
composite)
* Repeat 6-12 months
14-18 High risk (Secondary and tertiary prevention)
* As above and referral to a specialist prosthodontist
* Consider direct restorations (composite resin) or indirect
restorations (composite/gold/ceramic/metal ceramic partial
coverage/full coverage)
