Troubleshooting Hall Crowns

We receive many questions from practitioners with issues they have with Hall Crowns. For several years now we have had Erica work with us and she has put together the very practical guide below.

Hi everyone, guest blogger here today. I’m Erica, and probably a lot like most of you reading this. I am a general Dentist, and I did Tim and Sarah’s course a few years ago- it opened up the wonderful world of paediatric dentistry and I left feeling like I could tackle anything.

The theory is sound, confidence is high, you’ve done the talking to the parents, built up the child’s experience in your hands…. And then the darn hall crown just doesn’t fit like it’s supposed to.

Over the last few years, I have learnt and picked up many tips to try to make the process as easy and predictable as possible, and I’ll share them with you here now.

Problem: The separators are hard to fit

If the tooth has a cavitated lesion, or a previous interproximal resin or GIC restoration, then sometimes the separators can be difficult to place.

SolutioNS:

  • If it’s sharp cavitated margins tripping you up, and you have a compliant child, then light use of a high-speed bur should be able to help round them off, allowing the separator to slide in easier. This also works if it’s a square restoration margin.

    • Some topical LA on the gingiva may help here if you need to pass the bur close by

  • Having a few smaller size separators can get you out of trouble sometimes. We use green ones in these instances

  • Always do the difficult contact point first. You don’t want pressure exerted from the opposite side to make things trickier.

  • You could try to pass the separator under the contact point and then ‘pull it up’ into the contact

  • If there is tipping of the adjacent tooth, or a very deep margin, you may need to reconsider if a hall crown is the right choice for this situation. A conventional SSC would be indicated?

Problem: I have the hall crown selected for the right M-D width, but the tooth is really wide Bucco-lingually and the crown won’t fit!

This is particularly the case where previous caries or restorations have resulted in space loss, giving a dimensional discrepancy.

Solutions:

  • Choose a bigger size SSC. It will be too wide in the M-D dimension

  • Use Howe Pliers to squish the crown to reduce the M-D dimension until it will fit

  • This pushes the B and L dimensions out to cover these wider areas.

  • Hold the crown over the occlusal surface of the tooth, check all angles to ensure the outline of the crown covers the entire outline of the tooth when viewed from above.

  • Crimp margins a little to pull them in as they will be splayed somewhat

Problem: I have cemented it, but it seems to be sitting really high, or just didn’t feel right

Solutions:

  • If the cement hasn’t set, and you really feel it’s just not pushing down as you’d expect, take an x-ray to check! If it is not seated well, quickly remove it, and rinse away the unset cement with water. Reassess the fit and adjust as needed and try again

    • You can use forceps to remove the crown gently (without extracting the tooth!). You just squeeze bucco-lingually and then wiggle slightly until it comes off.

  • If cement has set – take an xray! If the caries margins are covered, you may be OK and you can monitor for it settling in over the following 1-2 weeks.

  • If the carious margins are not covered, then you will need to remove it. Section the Bucco-occlusal surface (with a high speed diamond bur- I use a flat fissure) and it should peel off, using U/S to remove excess cement. A band remover can also be used to chip away excess cement with the beak. You do not need LA for this if done well

  • You may find you need to do a few of these when you start out, and it’s a PITA, but you certainly learn from them!

Problem: The margins are deep and the hall crown doesn’t cover it

Even when the caries is the required 2mm + away from the pulp, sometimes the caries margin is still sub gingival.

Solution:

We routinely use the NuSmile SSC, but other brands like 3M have some that have slightly longer walls. Sometimes these come in handy! I understand not all clinics will be equipped with such options.

You could try increasing the size (hence longer walls), then using Howe’s to fit M-D width and crimp in B and L dimension

Usually even minimal reduction of the occlusal surface can result in sensitivity for the patient. As such, you need to consider placing a conventional crown for teeth with a very deep carious margin.

Problem: I’m worried about my hall crown impeding the eruption of the permanent teeth

 

Solution:

  • I always heavily crimp in the distal of my crowns in E’s when the 6 is unerupted.

  • If it transpires that a SSC overhanging margin does impeded eruption of a tooth, you could:

  • If the tooth is partially erupted, place a separator for a few weeks (may need changing a few times) to try to re-direct

  • You could remove the hall crown and replace with a better fitting one, hopefully by that stage the child is more compliant for such treatment

In conclusion, hall crowns can make treating little patients much easier and more enjoyable for everyone, and learning to mitigate possible problems is worth it in the long run. If you have any hints or tips you’ve picked up along the way, we’d love to hear them!

Tim Keys