Toothwear I

• What is tooth wear?

  The cumulative surface loss of mineralised tooth substance due to physical or chemo-physical processes (dental erosion, attrition, abrasion).

  Tooth wear is not considered to be the result of dental caries, resorption, or trauma.

  Erosive tooth wear is tooth wear with dental erosion as the primary aetiological factor

  
• What is attrition?


  Physiologic loss of mineralised tooth substance due to tooth on tooth contact
• What is abrasion?


  Loss of mineralised tooth substance due to a third body coming into the mouth and wearing away the teeth (e.g. toothbrush, pen chewing, nail biting, etc.)
• What is abfraction?


  1. Pathologic loss of tooth structure thought to be from flexure during mastication

  
  

  2. Wedge shaped defects to the cervical area (non-carious cervical lesions)

  
  

  There was poor evidence that occlusal forces cause tooth wear and so it is thought that abfraction doesn't really exist
• How prevalent is tooth wear in adults?

  77% of dentate patients have tooth wear into their dentine in their anterior teeth, 15% have moderate tooth wear and 2% have severe tooth wear (2009)

  
  

  Roughly a third of all European adults aged 18-35 have one surface with moderate tooth wear, 3% have severe tooth wear (2013)
• How prevalent is tooth wear in children?

  1,308 children were examined in Birmingham at the age of 12 years and re-examined 2 years later

  
  

  New or more advanced lesions were seen in 27% of the children over the study period

  
  

  12% of erosion-free children at 12 years had developed the condition over the 2 years period
• Is toothwear prevalence increasing?

  Yes, people are snacking more often, more soft drinks are being consumed, all of which can contribute to toothwear
• Recap on enamel:


  -96% mineral content = 3% water + 1% organic tissue

  
  

  -Outer layer of enamel contains no prisms = aprismatic layer. It has highest mineral content containing fluoride and phosphate (fluorohydroxyapitite).

  
  

  -Offers greatest protection against acid and mechanical challenges
• Recap on dentine:


  -75% mineral, 20% organic material and 5% water

  
  

  -Mantle dentine is close to enamel

  
  

  -Mantle dentine similar to aprismatic layer with only a few curved tubules.

  
  

  -Bulk of dentine = intertubular dentine (type I collagen rich structure) which has higher susceptibility to wear, such as abrasion.

  
  

  -peritubular dentine is formed within the linen of tubules, it is highly mineralised making it more susceptible to acid challenge.
• What happen when teeth are exposed to an acidic environment?

  -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.

  
  

  -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

  
• Contrast the chemistry of caries with that of erosion.

  Caries:

  InvolvessubsurfacedemineralisationInitial lesion has a small surface areaGenerally in protected areas with potential for localised application of remineralising agentsDeep lesionsOuter surface is generally harder due to fluoridationIncreased oral hygiene results in decreased disease progressionPlaque is a prerequisite

  Erosion:

  Involves "softening" ofsurfaceenamelNo protection from environment when demineralisedWide shallow lesionsOuter surface is softestIncreased oral hygiene may result in increased disease progressionOccurs on plaque-free surfaces

  
• Caries vs erosive tooth wear

  -main acid involved in caries = lactic acid present in the biofilm

  
  

  -hydrochloric acid + citric acid = dental erosion

  
  

  -Brushing helps improve caries but brushing can exacerbate erosive tooth wear

  
  

  For both it is important to find all of the risk factors, examine diet and examine oral hygiene

  
• What is normal brushing force?

  100-300g
• How easily can dentine be removed compared to enamel?

  Toothbrushing with a force of 400g has been shown to remove dentine and increase the number of patient dentine tubules so it is quite easily removed and this is even worse if it is acid softened dentine.

  
  

  However with enamel, it would require very aggressive mechanical wear to remove it in the absence of an erosive challenge
• How might tooth wear be presented to you by the patient, what kinds of phrases might they use?

  My teeth are short

  My teeth have dips/crevices in them

  My teeth keep chipping

  My teeth are flat

  My teeth are sensitive

  My gums are shrinking away

  My partner tells me I grind my teeth

  I wake up in the morning with pain
• How can you identify erosion early?

  Watch the maxillary central incisors and the lower first molars.

  
  

  It usually occurs on clean, plaque-free surfaces.

  
  

  Early stages can be difficult to distinguish with unworn teeth

  
  

  As lesions progress, it becomes easier to identify but the tooth may be compromised
• What does early erosive tooth wear (ETW) look like in anterior teeth?

  
• What does moderate ETW look like in anterior teeth?

  
• What does severe ETW look like in anterior teeth?

  Prevention is sill effective and can stop restorative cycle

  
  

  Shortening

  
  

  Chipping

  
  

  Large Buccal lesions

  
  

  Smooth and glossy labial and Buccal surfaces

  
• What does early ETW look like in posterior teeth?

  Loss of staining too

  
• What does moderate ETW look like in posterior teeth?

  Cupping on occlusal surfaces

  
  

  Increasing exposure of yellow dentine

  
  

  Changes to shape of teeth

  
  

  Shortening of teeth

  
• What does severe ETW look like in posterior teeth?


  Lesions start to merge

  
  

  Excessive dentine exposure

  
  

  Shortened clinical crowns

  
  

  Occlusal changes with alveolar compensation

  
  

  Prevention may slow progression and avoid the restorative/maintenance cycle

  
• What is the basic erosive wear exam (BEWE)?

  Simple tool to use alongside the BPE wherein you record the worse affected surface in the six sextants

  
  

  It's quick and efficient

  
  

  Designed as a screening tool to alert the practitioner and patient and does not indicate need for restorative intervention

  
  

  It grades all tooth wear; not just erosion

  
• What are the BEWE scores?

  0-3

  
• What are the management options depending on your patient's cumulative BEWE score?

  Add all the scores up across all sextants

  
  

  A 3 in any sextant is HIGH risk

  
• Can BEWE be used in children? What do you need to take into considerations?

  Yes, highest BEWE score in a sextant.

  
  

  Primary dentition wears at a faster rate than the permanent dentition

  
• How would you clinically manage BEWE scores?

  0-2 (primary prevention): no risk, routine maintenance, 3 yr intervals.

  3-8 (primary prevention) :OHI, dietary assessment, routine maintenance, review 2 yrs

  9-13 (secondary prevention): OHI, dietary advice, routine maintenance, fluoride measures, consider direct restorations, repeat 6-12 months.

  14-18 (secondary + tertiary prevention) :referral to specialist prosthodontist, consider restorations.