Why does my crown keep falling out?

Maybe it's not that into you.....? :)
              Being rejected by your crown hurts, especially when it was recently made and cost some serious money. Why does it happen? Usually either it has to do with the shape of the prepared tooth holding it or because the crown is ill fitting.

                For a crown to be retentive (resist the forces that may tend to remove it) the preparation has to be smooth and only SLIGHTLY tapered. It also has to be long enough to provide enough surface area to grab the cement. If the prepared tooth is too irregular, too short or too tapered, it may not have the proper shape to hold onto its crown.

                 Also, another possibility is that the crown can be cemented with a poor fit. In this case the crown does not hug the tooth well enough for the crown to stay put and since the crown is completely dependent on cement to stay. An analogy would be found in furniture making where most good furniture is made with dovetails, that increase the ability of the furniture to hold the wood together. Without dovetails, the pieces tend to work themselves loose more quickly. 
                 
                The same can be true with crowns, since their success is dependent on having a properly shaped tooth holding them and an intimate contact with it. The space between the crown and the tooth should be minimal (20-40 microns) in order for the cement achieve maximum holding power.

                   Most dentists faced with a permanent crown that comes out will first try to re-cement it. In my practice, I upgrade to a different permanent cement with more holding power. Unfortunately these cements do not always offer a long term solution and I am faced with the option of making the crown over.  When I do so I pay special attention to correcting any shortcomings in my tooth preparation and making sure that I take a perfect impression.

                  I should add a few  additional reasons that crowns can come loose. If the bite is high or just unfavorable, crowns can be more likely to come loose. Crowns do better when most of the occlusion is experienced along a  mostly vertical force vector and without much  of a horizontal component. Anterior teeth with deep over bites can experience a lot of horizontal forces on them and can sometimes be challenging to crown. Also some patients do have habits that are just not that friendly to crowns such as eating stale tootsie rolls or very hard and sticky candies. When chewed often these sweets tend to loosen even well fitting crowns


Dr. Pankaj Malhotra is a Periodontist & Implantologist in DELHI NCR region of INDIA, who maintains a practice in Noida. For more information about his Dental Practice please visit his website at www.dentalclinicnoida.in 

Do You Shop For your Dentist?

Almost every day my dental office gets a call from a potential patient shopping for a dentist. They ask for fees for certain procedures and often that is the end of the conversation. 

             I should note that my fees fall within the usual and customary range considered reasonable but for some persistent shoppers are too high. It seems that the internet has become the new Yellow Pages and potential patients are letting their fingers do the walking. It's not that hard calling a number of dentists and get a sense of the fees for the procedures that they will need. 

          Unfortunately, no information on the quality of the dental work can be gotten from these phone calls and shopping for dental work for some may be similar to shopping for furniture or other consumer goods. However teeth are not disposable and even implant replacements will not last forever.

         When I buy a piece of furniture, if I go to Ikea or any Local store, I expect to get a good price for what I buy, but I do not have the expectation that my purchases will last a lifetime or even ten years. It is asumed that there is a trade off involved with the inexpensive price paid but most of the time shoppers are  happy with their purchases . Many people like buying new furniture and actually like buying new pieces when they either tire of, or have to, replace them as they age.

            Teeth shouldn't be compared to furniture and restorations that are durable and preserve teeth for long periods of time are not always easily accomplished by dentists whose fees are the most reasonable. Although a higher price does not guarantee quality, it does tend to allow a dentist to to spend the time needed to create a thoughtful treatment plan and also the time to execute excellent restorative dentistry.
            I would like to quote a few examples here.. 

People dont mind paying 300 for Rs 30 popcorn in a theatre, but have reservations paying Rs. 300 consultation to a Dentist..

Also people dont mind paying 4000 bucks for a pair of jeans which shall last for 4-5 yrs and being worn for probably 100 times. While a crown of approximately the same value which you wear everyday and use it thrice daily lasts much longer than that..
             I guess the point of this post is to explain that price of services should not  be the primary method in choosing a dentist. Other attributes are quite important including but not limited to  recommendations from their patients, their skill level and their character.

Please contact me at www.facebook.com/dentistnoida
or https://plus.google.com/b/106703722934300581766