More often than not, patients ask me how long their restorations will last. Why should they get a crown when they have a filling that’s doing just fine? There’s a lot of factors that go into the treatment plan a dental practitioner creates, but I think it’s important to understand the longevity of the restorations that are being placed in patients’ mouths. In the end, nothing in dentistry is permanent (aside from pulling a tooth), and fillings and crowns are not meant to last forever. Let’s take a look at what research tells us about how long crowns should last.
What Factors Affect How Long My Crown Will Last?
There are various factors that determine the outcome of your crown, and it’s dependent not only on the dental practitioner but on the patient as well. When treatment planning a crown, there are various components that your doctor will take into account before placing it. This includes:
Determining the answer to these questions could give the physician and the patient a better idea about how long they expect their crown to last. For this post, we will be assuming that your dentist has taken into these factors correctly and the preparation and placement of the crown were ideal.
Let’s Review The Basics:
When a tooth has decay, it’s necessary to remove the decay and place a filling to replace the original tooth structure. Often, the filling may be so large that it requires a larger restoration – a crown – to be placed on top of the tooth in order to better support it. The larger a filling gets, the less likely it will last, and the reason crowns are recommended, instead.
So What Does The Evidence Say?
A study in 2018 was performed in Wales and England of more than 1.2 million crowns – all crowns were on adults. The study found that, overall, around half (53%) of the crowns that were analyzed lasted 15 or more years. It goes on to say that 63% survived ten years, and up to 77% five years1. The problem with this information is that it doesn’t take into account the following factors we discussed earlier – it’s not a longitudinal study that evaluates controlled patients by a certain dataset. This study gives us a great idea about the ‘general’ longevity of a crown using a massive amount of data. That being said, we don’t know about the general health of the patients that were given these crowns nor the expertise of the dental professionals that restored the crowns.
Let’s take into account another study that evaluated the differences between anterior and posterior crowns – this piggy-backs off one of the topics we reviewed earlier – not all crowns are created equal. This study starts off with the preface that there are expected differences in the longevity of anterior and posterior crowns. The study evaluated multiple papers and had a combined pool of data of 1122 anterior crowns and 1821 posterior crowns. In this study, ‘the results (group 2) indicated that the risk of anterior crown failure was around 50% less likely compared to posterior crown for the follow-up period of 5–6 years.2‘ This is to be expected – anterior teeth are subjected to fewer forces than that of the back teeth. That being said, this study illustrates a point that is problematic with this topic – studying the longevity of a crown over the course of five to twenty years proves troublesome, and controlling factors such as patient hygiene adds another layer to studying the longevity properly.
Whereas the last study focused on all-ceramic crowns, another study was performed that focused mostly on porcelain-fused-metal crowns (PFM’s). This is another type of crown that your dentist may recommend (but aren’t as common, now). This study was a longitudinal retrospective study and focused on crowns placed in between the years 1996 and 2011, and over 3000 crowns were evaluated. It was concluded that the type of tooth, the location of the tooth, and the gender of the patient had a significant impact on the success of the crown (men were more likely to have crowns that failed). The greatest determinant of the success of the crown was whether or not the tooth had been endodontically treated (had a root canal). which resulted in the most significant risk factor)3.
1Burke, F., Lucarotti, P. The ultimate guide to restoration longevity in England and Wales. Part 5: crowns: time to next intervention and to extraction of the restored tooth. Br Dent J225, 33–48 (2018). https://doi.org/10.1038/sj.bdj.2018.523
2Kassardjian, V., Varma, S., Andiappan, M., Creugers, N., & Bartlett, D. (2016). A systematic review and meta analysis of the longevity of anterior and posterior all-ceramic crowns. Journal of dentistry, 55, 1–6. https://doi.org/10.1016/j.jdent.2016.08.009
3Collares, K., Correa, M. B., Bronkhorst, E. M., Laske, M., Huysmans, M., & Opdam, N. J. (2018). A practice based longevity study on single-unit crowns. Journal of dentistry, 74, 43–48. https://doi.org/10.1016/j.jdent.2018.05.013
The medical advice given in this blog should only be utilized by a medical professional who has received a medical degree. I am not responsible for the medical advice given in this blog and each case should be reviewed extensively with sources outside my blog. This blog is for education purposes only and is not meant as a substitute for an academic institution.