Monday, 1 June 2015

A Guide to Orthodontics

This post is based on a study day I had with Priti Acharya.



As general dental practitioners, we often ask ourselves when we should refer patients for an orthodontic opinion and what cases may be suitable for treatment under the NHS? Whilst orthodontists will not mind seeing patients earlier rather than later, there are certain cases where early referrals are important. 

What we should remember, it's not really the age we look at when assessing a child's dental development, but more so the chronology i.e. are the teeth erupting in the correct order?

Appropriate early referrals:

  • Persistent habits
  • Missing teeth
  • Cross bites - an anterior crossbite can lead to localised gingival recession
  • Deep bites
  • Large overjets
  • Traumatic overbites
  • Gross skeletal discrepancies 

42% of 3 year olds suck their thumb (or another digit)
25% of 7 year olds also do

If we identify a habit like this, we should try to discourage this habit, at least so the child no longer does so by the age of around 6 i.e. when the permanent dentition comes through.
It is also important to try to correct the effects of thumb sucking, especially anterior open bites (AOBs) as correction in the permanent dentition is difficult and if surgery is required, there is a high rate of relapse - 43%

Ways to discourage a thumb or dummy sucking habit:
  • If they suck a dummy, to gradually cut 1mm off the dummy each week or give them an orthodontic dummy
  • Socks on hands at nightime
  • Plasters on fingers
  • Habit breaking nail polish
  • Reward charts/bribery
  • Fixed thumb guards - these need to be regularly reviewed by an orthodontist due to risk of digging into the palate

Types of Supernumaries

  1. Supplemental (of the same form)
  2. Tuberculate (barrel-shaped) - often cause impactions
  3. Conical - do not often cause compactions e.g. mesiodens
  4. Odontome - compound or complex
A conical mesiodens supernumerary causing an upper midline diastema

Supernumaries are more comon in females (2:1) and incidence is 2%

To identify the position of the supernumary, use the PARELLAX technique. Use the SLOB rule: Same Lingual, Opposite Buccal
Horizontal parallax techniques have been shown to be more reliable than vertical parallex (88% vs 69%), but the increased use of CBCT can also shown if there has been any resorption.

Parallex can also be used to identify the position of ectopic canines. Majority of normally eruption upper canines are palpable bucally by 10-11 years. 
A Cochrane review has shown that there is little or no evidence to support the extraction of primary maxillary canines to facilitate the eruption of palatally ectopic permanent canines, but sometimes it is still done as there is no harm come by the extraction of these teeth. 

Consequences of impacted canines:

  • Root resorption (12.5% radio-graphically but 48% on CBCT)
  • Cystic change, infection, pain
  • Ankylosis
  • Transposition

Infraocclusion


1-5% prevalence where a tooth is below occlusal plane of adjacent teeth.
When you tap this tooth (usually a primary molar), you will hear a high pitch sound which is a result of the tooth becoming ankylosed. 

Things to check for include: mobility and if there is a successor tooth (radiograph)

Extracting these teeth can be difficult and they are more common in the mandible than the maxilla. 


What can hypodontia (missing teeth) be associated with?

  • Spacing
  • Delayed eruption
  • Microdontia
  • Retained primary teeth
  • Impacted canines (there is a link between ill-formed lateral incisors and impacted canines as they are though to guide the canines into the correct space)
  • Taurodont molars
  • Conditions such as Down's Syndrome and Ectodermal Dysplasia

Management of missing laterals:

  1. Close space and alter canines/premolar with composite
  2. Open space for implants/bridgework
  3. Do nothing

Our role as GDPs is to make sure we refer patients when appropriate and early if need be. Every patient is entitled to an orthodontic assessment, so even if you're not sure a patient can be treated under the NHS, refer!

We also need to provide maintenance care during orthodontic treatment with regular exams and prevention and if the orthodontist requires any extractions we can provide this treatment too.
Maintenance doesn't just stop when the patient has finished their orthodontic treatment. Often these patients will have wither fixed or removable retainers so ensuring they follow their orthodontist's advice for LIFE is essential to prevent relapse. 


When would you refer a patient to an orthodontist early? Let me know your thoughts in the comments section below!


Why not take a look at my other Clinical Guide posts?

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