Carious Primary Incisors

Zirconia Crowns A new restorative material?

Radiographs are required prior to embarking on any treatment, including SDF

Restorative Options

Carious primary incisors are the most challenging teeth to restore out of any teeth across the primary or permanent dentitions. They have enormous pulps and very thin enamel. As such, any direct bonded restorations, such as GIC or composite resins have very low success rates in primary incisors. Further complicating the situation, children that have carious primary incisors are generally in the extreme caries risk category and pre-cooperative.

Severe Early Childhood Caries, you can see the milk on the gingiva, which is likely a key contributing factor

So how do we restore carious primary incisors?

Previously, we treated these teeth with strip crowns, which involved a pre-fabricated plastic shell that is filled with composite and bonded over the entire prepared tooth. Strip crowns are very technique sensitive and still only have a guarded success rate (<80% at 3 years). Anyone that has worked in paediatric dental clinics or hospitals knows the experience of spending several hours repairing failed resin strip crowns from previous registrars (and I am sure ours are still being repaired as well!).

There is still no perfect material but nowadays pre-formed zirconia crowns are available, and we use them with great success to restore the anterior primary dentition. They have several benefits including

·       Excellent aesthetics

·       Durable material and unlikely to fracture (kids bite all sorts of things)

·       If they debond, they can be recemented quite simply in the clinic if the patient returns promptly

·       Plaque resistant and great gingival response

Disadvantages include:

·       A steep learning curve to place

·       Commonly requires a general anaesthetic to place

·       Requires a significant amount of reduction

·       Expensive

·       May be very difficult, possibly even impossible, to adapt in cases of crowding

More research is being published regarding these pre-formed zirconia crowns as they have now been commonly used for around 10 years (particularly in North America). This research is demonstrating good success rates, which are greater than direct restorations and even strip crowns. As such, this is now our default material for restorations in the anterior primary dentition. But do we jump straight to a GA and place these?? Commonly, No…

If we are going to restore the teeth, the general steps involved are

1.     Address diet and oral hygiene. In very young children, it is almost always due to nocturnal breast-feeding and / or formula or milk at night

a.     A lip or tongue tie is rarely a major contributing factor. Keep in mind caries is a biofilm and behaviourally related disease…

2.     Start using a 1000+ppm toothpaste

a.     If the parents are anti-fluoride, we recommend Tooth Mousse (MI paste) and we delay restorative intervention until we are very SURE that they have modified other factors.

3.     Place SDF over the carious teeth initially, reapply 1 month later, and then review in 4 months

SDF applied at the second visit (1 month). It looks horrendous, but is an indication of successful cessation to lesion progression.

a.     Ideally, at 4 months, no disease progression has occurred and we can then proceed with intervention

b.     Some parents just don’t want to wait that long. For these, we still place SDF and address risk factors, but they need to demonstrate that these have changed prior to us proceeding.

c.     Arresting the carious lesions and delaying restorative intervention is particularly important for children who are less than 2-years of age

4.     Proceed with restorative intervention followed by a commitment for 3 – 4 month recalls with fluoride varnish.

Immediately following insertion.

1 month later - please excuse the blurred picture, he was a little moving target!

The technique for placement of pre-formed zirconia crowns can only really be taught at a hands-on course as they are much more challenging than stainless steel crowns. As such, we cannot really teach this over a blog (sorry).

Do We Always Restore These Teeth?

Actually, we do not always restore carious lesions in primary incisors and our treatments are provided on a case-by-case basis. We are big proponents of a minimally invasive approach, where appropriate. In children where aesthetics is not a high priority, we may place silver diamine fluoride for several years to buy some time until exfoliation or until the child has become more cooperative for restorative management on the chair.  We have actually done this in more cases than we have placed zirconia crowns. but this is a topic for another day!

Summary

Restoring the anterior primary dentition is a very challenging process. It is generally on pre-cooperative children with extreme caries risk factors. We like to address these factors first and for some parents, SDF application is an acceptable form of treatment and can help avoid a general anaesthetic. For those that have advanced disease or higher aesthetic demands, pre-formed zirconia crowns are the restorative option of choice.

We are passionate about encouraging dental practitioners to successfully manage paediatric patients in the clinic when they can. Even for us, management options on the chair are limited, with SDF being the primary means (where appropriate) to address these lesions. Many of these cases are very challenging to manage, and if you struggle to get an examination and radiograph completed, an early referral to a paediatric dentist is advised as these can spiral out of control very quickly