Saturday, 1 April 2017

Hall Crowns: Top 10 Tips

In community I see a lot of uncooperative or anxious children. A useful technique I use almost every day is the Hall technique in the placement of stainless steel crowns (SSCs) on primary molars. This was something that took a while to get good at; so here are my top 10 tips.



1. Avoid small Ds

In general, Es are easier to place SSCs on but sometimes you need to consider the same technique on Ds. Small Ds can be quite tricky to place with a Hall technique (especially lower Ds) due to their buccal bulbosity. 

Sometimes when I am assessing the tooth, if I see it's quite small (smaller than a D5 preformed crown), I wouldn't usually attempt a crown and instead opt for a conventional filling if possible. If you really want to place a crown on a D some useful tips I found useful are:
  • When placing the crown, roll it from buccal to lingual/palatal to overcome the buccal bulbosity
  • Try to always place separators (seps) to create space
  • If you are struggling, prep to remove the buccal bulbosity (you may need LA for this)
  • For very large Ds, consider using the smallest E size as a last resort when a D7 is too small


2. Seps are uncomfortable

Placing seps can be a pain and children often find it uncomfortable as you sometimes need to use a lot of force to floss the sep into the interproximal space. 

The teeth can also ache afterwards while the separator does its work. I have seen children pick them out as they don't like the feeling of them (imagine something stuck between your teeth that you can't get out!). 

I have also seen seps that are left in for too long and then have sunken through the contact point into the gingivae. This can be very uncomfortable for the patient and getting them out can be so even more and can be very tricky in a child who is not very compliant. Always warn the parents of these risks and ensure if you are going to place seps, they are ideally not in for more than 1 week. 


3. Prepping isn't bad

I know a true Hall technique involves no prep or caries removal. Ideally, you would want to remove some caries even if this is just with a hand excavator and in some cases a quick slice through a contact point with a bur doesn't even require LA and is a quick way to ensure you can seat your crown.

If you are going to prep, I tend to just remove the contact points and any buccal bulbosities. Be careful if you are prepping near a 6 to ensure you don't damage that tooth and in some children behaviour management can be challenging when using a handpiece. 


4. Don't worry about occlusion

You won't hear dentists say that much. In the primary dentition, occlusion is changing all the time and children are very adaptable. Evidence also shows that within weeks, increases in OVD are very minor and it is thought this is due to intrusion of the opposing tooth (there is no evidence that this damages the successor).

It can feel unnatural initially cementing in a crown where a child is clearly very jacked open but they adapt over time. Always warn the parents prior to cementing (and the child of course) and analgesics may be required to make it feel more comfortable initially. 


5. Avoid doing upper and lowers on the same side together

Although I've just said don't worry too much about the occlusion, avoid placing SSCs on opposing teeth at the same time. This is because the change in OVD can be quite significant and will be more uncomfortable for the patient.


6. You need to press HARD

Don't be afraid, in most cases you need to press firmly to seat the crown. The main method I use is to ask the patient to bite together hard either on a cotton wool, tongue depressor or orthodontic band seater. In some cases however this may not be appropriate e.g. if there is no opposing tooth. The other trouble with that method is you need the child to comply to bite hard - many either only bite gently because of the feeling of tightness of the crown, or in younger children or those with learning difficulties they may not be able to follow your instructions fully.

In those cases you will need to press down hard - the satisfaction when you hear the 'click' of the crown seating fully reassures you that the crown is seated fully (often the gingivae will blanch to show you it's seated slightly subgingivally, which provides an excellent seal).


7. Consider for 6s if poor prognosis

Most people only consider SSCs for primary molars, but they can be useful for 6s in the developing dentition. Obviously you will need different preformed crowns, but you need to use them slightly differently to primary SSCs (I wouldn't want to change the occlusion that much).

 I use SSCs in cases such as:
  • Hypomineralised 6s to protect against further breakdown
  • Carious 6s of poor prognosis where you would like to hang on to them until you take them out at the right time for the 7s to come into position (working alongside an orthodontist). Note you need radiographs before you place the crowns so that the extent of the caries can be assessed at a later date
  • On permanent molars which have been root treated in teenagers where you require cuspal coverage but you don't wish to do a conventional crown yet either for occlusal reasons or compliance issues. 



8. If you don't seat fully, it's not the end of the world

Getting that click as you seat and seeing blanching gingivae is the ideal, but sometimes it's not always possible to fully seat (for example if the child doesn't bite down fully).

You are aiming to seal in any caries, so as long as the caries is sealed in that is acceptable. In my experience, if this does happen it's most likely to be an exposed palatal margin. 


9. Consider preventative SSCs

Traditional Hall crowns have been indicated in:
  • Cavitated or non cavitated proximal carious lesions
  • Occlusal caries if a child cannot tolerate a conventional restoration
However, I also find placing SSCs in more of preventive approach can be useful. For example, for children with high caries rates who have caries in the majority of their primary molars at quite a young age, I would consider crowning at least all the Es even if they don't all have caries in them yet. 

I have also placed crowns in some children with complex medical issues or learning difficulties where they suffer from lots of reflux or vomiting to protect from wear. 



10. They are tight!

When I first started doing SSCs I didn't appreciate how tight they can feel for children. I have had many a child be a bit teary after I place them because of that feeling of tightness (they get used to it quickly) and you need to learn to reassure both them and their parents. 

Again preparation is key so explain to them it will feel tight. The analogy I use all the time is trying on a new pair of shoes that are tight at first until you wear them in. Always advise the parents to give appropriate analgesia in some cases for 1-2 weeks until the child adapts. 


To read more about Hall crowns, there is a really good summary article in the most recent BDJ.


Do you do SSCs? What tips do you have? Leave them in the comments section.



No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...