What causes sensitivity in crowned teeth?

Traditionally dentists have believed that this sensitivity stemmed from cracks in the teeth, previously injured pulps, and dying pulps. Some 'traditional cements' have been known to occasionally cause a pulpitis when they were used for cementation ( Zinc phosphate and glass inomer cements). This type of cement induced sensitivity occurs immediately after a crown has been cemented and the symptoms are predominately sensitivity to cold liquids. This sensitivity often goes away with time. In my experience it can take up to a year to resolve, but occasionally a tooth may require a root canal in order to resolve the problem of this cement induced sensitivity.


Recently new resin based cements have become popular with many dentists and they may be to be causing a whole new category of sensitivity. Although they can cause traditional type of cement sensitivity, most times they do not. They have the advantage of actually 'bonding' to the tooth. Supposedly, this is an advantage, but the problem in my mind is that under chewing pressure and function this bond may fail. If that happens, the crowns often do stay in place, but probably become leaky. This leakage can cause sensitivity and can cause sensitivity to biting as well, since under pressure the crowns may flex very slightly against the tooth.

I do use some of the newer resin based cements and I have experienced some patients who have complained of this newer form of 'delayed sensitivity'. Recently I tried an experiment. I had a patient who was complaining of sensitivity every time she drank cold. Her crown was cemented with a resin based glass ionomer cement and seemed well fitted and well cemented.

I removed the crown and fabricated a traditional acrylic temporary cemented with a eugonal based temporary cement and her symptoms immediately disappeared. Although this a sample size of only one, I wonder how many other patients are experiencing the same problem?

What is the difference between an onlay and a filling?

An onlay is an restoration that is made in a dental laboratory that is designed to protect a tooth that whoose tooth structure has been compromised by decay or by the preparation made for prior fillings. Usually onlays cover the chewing surface of the tooth including the cusps . The design of an onlay can protect a tooth and make it less likely to suffer a future fracture. When designing an onlay, a dentist must create enough clearance between the tooth being restored and the opposing arch. The ideal amount of reduction of the occlusal reduction is approximately 1.5 -2mm,; enough thickness to allow for a durable restoration. When designing the onlay preparation a dentist should remove any prior tooth structure as well and often onlays can become partial coverage crowns. They differ from crowns in that more tooth structure is left intact on a tooths buccal and lingual surfaces.

It used to be that onlays were a two sitting procedure, but now with the advent of cad cam technology, it is possible for a 'high tech' dentist to prepare and place an onlay in one sitting. This technology is expensive and most dentists have not yet invested in purchasing an on site cad cam milling machine.

Onlays can be cemented in with a number of different types of dental cements. At present most ceramic or composite onlays are 'bonded in' with a composite resin cement. When cementing in gold onlays dentist have a wide variety of possible cements to choose from. I personally use old fashioned, but tried and true dental cements that are resin free.

Fillings, on the other hand, are usually inserted directly in the tooth during one sitting. They are not made on a bench or in a cad cam milling machine, but placed in the mouth by the dentist. They can be made from a variety of materials, including amalgam, composite, glass ionomer, and even gold. With care, they can also be used to onlay and protect cusps, but because of the difficulty in placing well made large multi surface fillings, usually laboratory onlays or crowns are a better choice for a dentist to use when restoring a tooth with compromised tooth structure.

What's New with you Dr Spindel?

People as me this all the time when visiting my office and today I am pleased to report that About.com has posted three of the four videos that were filmed at my office last August by videographer Heidi Dehncke-Fisher. These can be viewed on About.com at the following Urls:

http://video.about.com/dentistry/Gum-Care-101.htm

http://video.about.com/dentistry/How-to-Brush-Teeth-With-Braces.htm

http://video.about.com/dentistry/How-to-Brush-Teeth-With-Braces.htm

http://video.about.com/dentistry/How-to-Floss-Properly.htm

I think she did a nice job with the videos especially considering my prior lack of "on air experience".

How do I keep kids from getting cavities?

Regular visits to your dentist, a good diet and brushing habits and having dental sealants placed on all pits fissures of adult posterior teeth can make cavity formation less likely.

Diet plays a big role in the formation of cavities. Acidic food can help dissolve enamel and sugar as well as carbohydrates can be easily metabolized by the bacteria that cause caries. Try to limit your child's sugary snacks and carbonated sodas are thought to be especially harmful to teeth and bone.

During dental visit, children's teeth are inspected, hygiene instruction is given, persistant plaque is removed and fluoride treatments are given. All of these steps can help prevent cavity formation. Also the dentist or hygienist can place pit and fissure sealants on the grooves of the permanent posterior teeth. Sealants are well documented as an effective way to prevent decay.

Is the recession over?

I am no expert on the economy, but in my experinence as a dentist for twenty five years in New York, I have observed that each recession that my practice has experienced, has ended with a wall street recovery leading the way. It seems to me that there are some hopeful signs that the economy is starting to recover. Wall street is making money again, and there probably will be many bonuses given this year.

I have noticed an uptick in car advertisements on T.V. I went for some test drives on some new cars and was surprised that used used car prices are up and to me new cars seem more of a bargain than they previously were.

Also today, I was cleaning a patent's teeth who works for a head hunter agency and was told that that hiring is up. This seems like very good news.

Most of my patients with jobs relate that their work load has never been higher and they are stressed out. They are often afraid to keep their scheduled appointments, as they feel leaving their jobs may make it appear that they are not 'truly committed' to their jobs (No one wants to be included in the next wave of job cuts).

CEO's maybe deciding that it is time to stop the job cutting. In general being 'Lean and Mean' is good, but how lean can you get before your ability to do business suffers. It stands to reason that as businesses become profitable again , their hiring may pick up.

Of course there are still are a lot of New Yorkers in search of work, but maybe they will have more job interviews now than earlier in the year. Even if there is an uptick in hiring there will be a large pool of applicants for each job opening. My dental office schedule still has some openings that I wish were filled, and nothing is certain. Let's hope that the signs for economic recovery are good and that they only get better.

What electric toothbrush is the best value?

In my opinion the Oral B Vitality is the best toothbrush value. It retails for about twenty dollars and it does a good job as well when used as instructed. It will out perform most manual tooth brushes ( unless they are skillfully used!). It is great for both kids and adults. We often carry this brush in our office due to its affordability.

How do I keep my kids from getting cavities after eating too much Haloween candy?

When I was a child, I was an over achieving at ‘trick or treating’ on Halloween. Not surprisingly when I went to the dentist for a check up I would invariably have multiple cavities!

Halloween is a fun holiday, but excess candy consumption by kids in the thirty days afterwards can definitely make cavities more likely. Free candy is enticing, but the resulting tooth decay and needed dental visits afterwards are not without cost.

Why not plan a Halloween party that emphasizes fun and games and limit trick or treating to less than one hour? It just may prevent cavities and help preserve your child’s teeth.

Do you recommend using any over the counter mouthwashes or rinses to remove placque or whiten teeth?

I am leery about patients using mouthwashes on a regular basis. Antimicrobial hand washing has been shown to be counter productive and it is entirely possible that antimicrobial mouthwashes may not be good for us in the long run.

They may change the bacterial flora of the mouth, killing both harmful and beneficial bacteria and can cause an over abundance of candida albicans (yeast). Also what are the long term effects on the soft tissues of the mouth?

I personally advise my patients to keep it simple and stick to the basics-brushing and flossing ( or some other method of cleaning interproximally).

How to deal with rubber dam panic?

Some patients become extremely apprehensive when a rubber dam is placed in their mouth. Patients who experience this usually report they 'feel like they are unable to breathe'. The cure is often simple. I cut a small hole in the rubber dam and explain to the patient that they will now be able to breathe through their mouth with the rubber dam in place. Usually this works for the 'rubber dam phobic patient' and they allow me to leave the dam in place.

If I have PPO dental insurance should I go to a participating dentist?

There is no definitive answer to this question. Each person with dental insurance must make this choice for themselves.

PPO dental insurance allows you to go in or out of network. Often going out of network affords you the opportunity to be exposed to a far greater number of dentists. Many dentists do not need to participate in these plans since patients continue to utilize their practices due to the respect they have for their dental skills.

If you have a PPO plan you may want to consider using an out of network dentist, since even though you may experience greater out of pocket contributions, you may benefit in the long run and will be seeing a dentist truly of your own choice.

Can mouth breathing cause anterior crowding?

Most dentists believe that chronic sinus problems , over the long haul, can affect the pattern of the jaws bone growth. This altered pattern tends to make the vault of the hard palate deeper and also change the shape of the jaws in such a way as to cause anterior crowding.

Mouth breathers tend to have a 'V' shaped arch instead of the classic 'U' shaped one. This can make central or lateral incisors over lap and make orthodontic intervention necessary. If you child has difficulty breathing through there nose while asleep they may be causing long term changes in the shape of their jaws. Accordingly, discussing the matter with your pediatrician or pediatric dentist would be advisable

Can temporary crowns be repaired?

Yes they can. Often temporary crowns crack, wear or turn more yellow over time. If they are made from acrylic they can be easily repaired. Acrylic will accept the addition of new acrylic . If I have a patient with a cracked posterior temporary and it needs a repair I first clean out all the temporary cement residue. If there is a cracked portion, I freshen that area up with a diamond bur and then I re seat the temporary. A slurry of acrylic is added, usually with the temporary in place, and allowed to set. Afterwards the temporary can be trimmed, polished and recemented.

For anterior temporaries which have chipped or changed colors , I find I can make small additions using tooth colored composite materials. I use these to either to lighten the color of a temporary that has turned more yellow or to repair small chips on the incisal edges. The additions usually adhere reasonably well and patients are able to extend the useful life span of their temporaries.

What does it mean if my tooth hurts after I have a temporary crown placed?

This is a question that I am frequently asked. It is common for freshly prepared teeth to be sensitive when a new temporary is placed. For many years dentists cemented temporary crowns in with sedative temporary cements that contained eugenol . Eugenol is an abtundent and it can calm down an irritated pulp, but it can interfere with bonding agents. In the last ten years, as composite cements have become more popular, dentists have been using less eugonol based temporary cements.

Accordingly the number of sensitivity complaints have probably gone up. Preparing a tooth for a full coverage crown can create irritation in a pulp and create temporary sensitivity. Most times it goes away eventually. Occasionally teeth do not calm down and may require endodontic therapy.

Other common possible causes of sensitivity of teeth with temporary crowns can be high bites or incompletely covered preparations. These can be easily corrected by a dentist. If you do have sensitivity after having a temporary placed it is a good idea to let your dentist know.

If I have a patient who still has this sensitivity when I am trying in the permanent crown, sometimes I choose to cement the permanent crown with a temporary cement, just to allow the tooth to calm down prior to permanently cementing the crown. If the tooth remains 'unhappy' even with the permanent crown temporarily cemented endodontic therapy is an option that may have to be eventually considered.

What are the top 100 dental industry blogs?

I am pleased to report that The 'Ask Dr Spindel' dental blog has been cited as one of the top one hundred dental industry blogs. The posting can be found at http://dentalassistingschool.org/top-100-dental-industry-blogs/ and lists what the author feels are the best dental blogs.

The list not only includes top dental blogs but also lists a generous helping of other dental industry websites, pod casts and and relevant Internet articles. The author has made a comprehensive list that may be of interest to anyone seeking dental information or just needing a 'dental information fix'.

Where in the world is Laurel Touby?

I am experiencing a serious case of jealousy. My patient, Laurel Touby, just came in and announced that she is taking a sabbatical and travelling for the next six months. She is planning to post blog entries along the way and I will, for the moment, live vicariously by reading her posts. She will be posting her adventures on her blog at: culturetripping.com.