S2 - Iatrogenic effects of orthodontic tx Flashcards
What is/isnt a benefit a HEALTH benefit of orthodontic tx?
doesn’t: prevent caries, perio, treat TMD
does: prevent dental trauma in pt’s w increased overjet BUT…
most traumatic dental injuries take place in the mixed dentition (before ortho tx)
Does ortho actually benefit: impacted teeth, masticatory efficiency due to occlusion, speech - explain why/why not
Unerupted impacted teeth - other than 3rd molars seem to give few problems in adult life
Treatment of severe functional problems with occlusion - almost no difference in masticatory efficiency has been reported in patients with excellent occlusion vs those w most types of malocclusion
Effects on speech - no evidence of causal relationship between malocclusion and speech problems
What IS a known benefit of orthodontic treatment. What should you know about it
improves self esteem
BUT the effects are transient
Which patients would benefit from ortho the most according to IOTN (Index of treatment need)?
- extensive hypodontia (more than 1 tooth per q) + restorative implications
- increased OJ > 9mm (risk of trauma)
- impacted teeth
- reverse OJ >3.5mm (masticatory, speech difficulties)
- less extensive hypodontia
- deep bites (palatal trauma to upper incisors, labial trauma to lower incisors)
Where do MOST patients fall in the IOTN?
moderate to little need for treatment, need to educate pt that tx is mainly aesthetic
Where do MOST patients fall in the IOTN?
moderate to little need for treatment, need to educate these pts that tx is mainly aesthetic
How does ortho increase risk of caries?
surface morphology altered - brackets are plaque trap, sugar adheres to tooth for longer
Most common dental risk of orthodontic treatment?
WSLs
What are WSLs?
decalcification is the loss of mineral from the tooth
demineralisation and remineralisation is a cyclical process
clinically appears as a white or brown spot on tooth surface, can progress to cavitated lesion
How common are WSLs? Which teeth are most affected. Name 3 risk factors
- reported incident of as high as 97% (50% more likely w ortho)
- maxillary lateral incisors*
- risk factors: longer ortho tx, pre-existing WSLs, poor pre-treatment OH
*in mx followed by centrals, canines, pms then ms but md is opposite - molars, pms, canine, lateral, centrals (likely cos location of salivary glands)
Issue with fluoride containing adhesives and elastics in orthodontics? Disadvantage of GIC to bond brackets?
- fluoride containing adhesive/elastics: initial high release of F but not reservoir or slow, extended release like GIC - limited effect
- GIC: much lower bond strength, risk of debonding
Current evidence for fluoride containing products to prevent WSLs during fixed braces tx
- low level of evidence supporting professional application of F foam every 6-8wks and high F toothpaste for home application
- but insufficient evidence to recommend F releasing products attached to braces
What is the best method of preventing WSLs?
dont start tx in pt’s who dont have excellent OH
teach pt’s how to keep teeth clean with ortho appliances
Explain why high conc F is not recommended for WSL treatment. What should be done instead?
- the surface of the lesion remains quite mineralised but the subsurface is demineralised (this is what makes it white/brown)
- application of high conc F leads to cessation of both demin and remin of WSL subsurface lesion due to hypermineralisation of the surface of enamel, making the subsurface impermeable (want to remin from surface out not other way)
- therefore, high conc F is not recommended and pts should brush as normal w 1500ppm toothpaste 2x a day to maintain benefits of F while limiting possibility of causing hypermineralisation
Treatment protocol for WSLs
No active tx for 3m if not cavitated:
- brush with F toothpaste 2x daily
- sugar free chewing gum
- tooth mousse (CPP-APP) - can put on delivery tray or retainers for 3-5min after brushing
If still present after 3m:
- leave if not cavitated
- microabrasion
- bleaching
- veneers (in very severe cases)
What type of orthodontic forces and resorption are more associated with root resorption?
heavy forces which cause blood vessels to be occluded and completely obstruct blood flow, causing sterile necrosis and hyalinised PDL → undermining resorption more associated with root resorption
whereas frontal resorption is not as much
Explain process of root resorption in orthodontics
force → over-compression of PDL causing sterile necrosis and hyalinised PDL
→ activation of local inflammatory reaction which removes necrotic tissue and begins repair of defect
→ resorption of cementum occurs simultaneously with removal of hyalinised tissue resulting in formation of resorption craters (location of the RC relates to type of tooth movement)
→ as resorption crater expands, indirectly decreases pressure exerted through force application
→ decompression causes the process to reverse and cementum reparative process begins
→ resorption continues until no hyanilised tissue is present and/or force level diminishes
