Fixing Broken Teeth FAQ.

Or: How can you mend a broken tooth?

The choice of an appropriate way to repair decayed or broken teeth may at first sight seem capricious or arbitrary, but it is not. We discuss amongst ourselves...

Q: I have a large molar which had a large filling put in years ago. It started being sensitive to air, cold, and heat. The dentist said it has many "fractures" in the tooth so it needs a crown. Crowns are expensive these days, so I am wondering what other options might there be?

A: There are fractures, and then there are FRACTURES. There are always small fracture lines running through the enamel of all teeth, and these are of little consequence. More serious are those that propagate through the deeper layers of dentin; these definitely create structural weaknesses, and may even involve the pulp of the tooth. Unfortunately, it is sometimes impossible to determine the extent of fractures without removing the filling in a tooth, since they are not well visualized on x-ray.

The decision as to when a tooth should be restored by crown rather than by filling is a subjective one, but not necessarily a blind guess. A dentist with relatively few years of experience will know when a tooth is in danger of cracking; for those who are fresh out of dental school, there are general guidelines that are remarkably accurate in pointing the way to an appropriate treatment.

For teeth that need more than a filling, a crown is the most commonly prescribed restoration. There are other restorations that will protect the tooth against further cracking (e.g., onlays or 3/4 crowns), but a full crown has the additional advantages of superior esthetics, retention, and protection against recurrent decay. It is also not significantly more expensive than the alternatives.

Compromising the treatment by the inappropriate use of filling material may be a short-term economy, but will ultimately cost you more. In the end, the tooth will break, necessitating the treatment you perhaps should have done in the first place; the tooth may even become non-restorable and require extraction. By comparison, the fee for a crown may be a small price to pay...

Q: Which is more durable-- a crown made of porcelain or one of gold? Are there other advantages of one type over the other?

When appearance is not a consideration (for instance, in a back tooth) which would you recommend and why?

A: Gold is slightly more durable than porcelain, but improvements in ceramic technology have narrowed the gap. We don't see nearly the number of porcelain fractures today as we saw 25 years ago.

Porcelain has two advantages over gold: it looks better, and (marginally) it is smoother, so it tends to discourage plaque accumulation slightly more effectively than polished gold. This second difference is theoretical, and has little clinical significance.

The one major disadvantage of porcelain is that it is so hard that it will abrade anything opposing it unless it's also composed of porcelain. Over time, this can cause significant loss of enamel on a tooth opposing a porcelain crown, requiring additional restorative treatment. For this reason, where cosmetics is not an issue and/or the opposing tooth is not porcelain, a gold crown is the superior choice.

Q: Are gold dental crowns better than porcelain-fused-to-metal crowns?

A: Whether a choice of restorative material is better or worse depends on its suitability to the specific situation. In the U.S., most people wouldn't think of having a gold crown in a position where it would be plainly visible. Being in New York, which has a substantial immigrant population, we have had several foreign-born patients request a gold crown be placed in a front tooth. It's mostly a question of cultural concept of aesthetics.

As a restorative material, many dentists favor gold. We suspect this has much to do with nostalgia for the "Days of the Giants", as our professors in dental school were fond of saying. Gold is a soft, ductile metal which is chemically and biologically inert, and easy to cast and machine accurately. This was not the case with early base metal ceramic alloys, which were hard, brittle, and elicited allergic reactions due to their nickel content. These problems have been largely eliminated in modern porcelain fused to metal crowns.

Although gold crowns can be highly polished, ceramic crowns are said to theoretically resist plaque accumulation better due to their highly glazed surfaces. We think oral hygiene has a greater impact on plaque accumulation, for what it's worth.

A dentist will tell you "there's nothing so beautiful as a well-done gold crown", but we suspect you won't hear that from a patient. What can we say-- dentists are a strange breed! ;-)

Q: This past year, I have had a few dental fractures and had one again last night!! I was biting down and-- crack!

What is wrong? Is it a lack of calcium? I don't drink much milk or eat much cheese.

My dad had "soft teeth" back in the '40's and had them all extracted and got false teeth at 32 years of age. Have I inherited something like that from him?

I have lots of fillings and several crowns now. What should I do?

A: Quality of diet is thought to have little effect on the strength of adult teeth.

Occasionally, there can be a sudden increase in the forces applied to the teeth, as is the case when a person develops a tooth grinding habit or seizure disorder. Assuming that this is not the case, the problem is some kind of structural weakening in the teeth themselves.

Teeth may be weakened by active decay, or by the placement of large fillings to restore decay. Often the weakening produced by the resulting loss of tooth structure does not manifest immediately. However, over time, chewing forces slowly act on these weak points, creating microfractures that propagate through the tooth until it finally breaks.

There are broad guidelines that dentists apply when deciding the proper way to restore a broken or decayed tooth. These guidelines occasionally point the way to an inappropriate treatment, or perhaps the dentist or patient compromise an "ideal" treatment plan for reasons of time or financing. In either case, a choice is made where a filling is placed where, in retrospect, a crown or onlay may be proven to have been a better choice of restoration.

It is probable that you are now reaping the result of just such past compromises. Perhaps large fillings were placed where a crown would have served you better. No matter; most fractured teeth can be restored by placement of a crown. This will reinforce the remaining tooth structure and protect it against future breakage.

We'd advise you to consult with your dentist. In addition to the broken tooth, he may be able to detect other teeth that have a high probability of breaking in the near future. If you dislike surprises, you may want to consider pre-emptively crowning these weakened teeth before they break.

Q: Hi! I am a 45 year old female and I take a lot of medications, one of them a steroid, which I have to take for serious asthma. My teeth are constantly breaking . I mean CONSTANTLY!! Like every week. I only have about 12 teeth left and my dentist will fix one and before my next appointment another one will break. I want him to just pull the few I have left and give me some nice pretty dentures. They are trying to get x-rays and impressions taken to make me a partial denture, but my gag reflex is SOOOOO very bad they could not even get x-rays! They even tried the baby films for x-rays! So, my 2 questions are:.

  1. Is there ant thing I can do to prevent my teeth from breaking?
  2. Is there anything my dentist or I can do so he can get some good x-rays and some impressions?

I would very much appreciate any help you can give me. Thank you in advance.

A: The most common cause of tooth breakage is the placement of large fillings, which structurally undermine the tooth. The placement of crowns on these over-filled teeth will usually reinforce the teeth and prevent them from breaking. Oftentimes, a dentist will place fillings when they may be inappropriate if a patient cannot afford the larger fee of a crown. This short-term economy can backfire if breakage results.

The gagging reflex is a normal protective mechanism that serves to prevent aspiration of foreign material into the respiratory tract. In some individuals this reflex may be hyperactive, and interfere with dental procedures. There is nothing unique to your problem.

Dealing with gagging:

  • Sometimes the gag reflex can be temporarily suppressed by spraying a topical anesthetic such as Cetacaine on the sensitive areas of the palate and tongue.
  • Some dentists have dealt with this problem successfully through hypnosis.
  • It is sometimes possible to take a sectional rather than a full-arch impression, which will present less of a stimulus to gag.
  • X-ray technique usually will involve some combination of breathing exercises by the patient, flexing of the x-ray film packet to render it softer and more flexible, compromising on x-ray film placement in order to avoid sensitive areas, and sprint training by the dentist in order to get the film packet placed, exposed, and removed in the shortest period of time.
  • Failing that, a dentist may be able to use extra-oral x-rays such as a panoramic machine. These do not stimulate gagging, but may compromise the x-ray image clarity and resolution. If your dentist does not have a panoramic machine, he may be able to refer you to someone who does.

Be mindful of the fact that x-rays and impressions are brief experiences that pass quickly. More potentially problematic is the impact your gag reflex may have on your tolerance for removable denture prostheses. The more teeth you have extracted, the larger the prosthesis, and the greater the probability that you will have difficulties adapting. I would advise you not to be so quick to extract teeth that are salvageable.

Q: I had a triple root canal in a wisdom tooth about 4 years ago, and now the filling came out. I saw another dentist, who suggested I have a crown put on it this week. What exactly is a crown, how long does it take to put on, how long does it generally. last, what are the benefits/drawbacks, and what cost can I expect?

A: In choosing what kind of restoration is appropriate for a broken-down tooth, a dentist must decide whether a tooth is too weak to support or hold a filling. Restorations placed inside teeth depend on the surrounding tooth structure for their support. If this tooth structure is too thin or of insufficient quantity, the tooth and/or filling combination will break. That is apparently what happened with the filling in your wisdom tooth.

Rather than obtaining its strength from the surrounding tooth structure, a crown confers its strength to the tooth; it covers and surrounds the tooth, protecting it from potentially injurious chewing forces with its own inherent structural strength.

There are different materials used for crowns, usually some combination of metal and ceramic. Placement of a crown restoration usually takes 2 to 3 visits. The benefits of a crown over a filling include both improved appearance and durability. Crowns will generally last 10 years or longer. The fee varies widely, depending more on locale than quality; expect to pay $200 - $1000 in the U.S.

Q: If money is no object and all-metal crowns are not to be considered, what is the "Rolls Royce" of crowns for a MOLAR. I know about PFM crowns and I understand they come in various categories, from base to noble metals, and even the latter are subdivided in subcategories. I also know about porcelain crowns. But I just read that there are new porcelain crowns that are supposed to be even better than PFM. So:

  1. What is the best crown for a molar (precise name, please)?
  2. Approximately when has this type of crown been introduced (months or years ago)?
  3. What are its advantages (and disadvantages, if any, especially as compared to other types)?

A: The best crown for a molar? That's like asking which is better, a golf cart or a bicycle. The question is not whether one is better than the other, but which is more appropriate for the presenting clinical situation.

Don't get us wrong; there are certain physical parameters that define what is a "good" and what is a "bad" crown. These parameters apply regardless of the material used for crown fabrication. If the bite (occlusion), marginal fit, and contact with adjacent teeth are improperly or carelessly executed, the crown will be bad whether it is cast base metal or full sintered ceramic.

The decision is based more on a dentist's familiarity with a technique, the laboratory technician's skill with a particular material, and the clinical application. The cost of the material has no bearing on whether it is most appropriate for a particular application, either.

Full cast base metal crowns are entirely appropriate for use in second molars, for instance, since their silvery appearance does not present a cosmetic liability where it will not be seen; it is less expensive, and it is stronger than a ceramic restoration.

Base metal is also preferable for ceramo-metal fixed bridges, since it is more rigid than precious alloys, and will be less likely to flex and "pop" the porcelain.

Precious alloys are preferable where their softer nature permits milling of semi-precision attachments for partial dentures; in this situation, noble alloys have their advantages. All-ceramic crowns are less likely to show an obvious margin on a front tooth if gum recession occurs over time, though they are not as strong as ceramic/metal combinations.

Dental laboratory technology is no less prone to the hype that has permeated dentistry. There are new materials being developed and marketed all the time, in the hopes of curing problems that don't exist. These "revolutionary" developments necessitate tooling up and training, which are additional expenses that seldom yield any advantages over established technique. Far more relevant to the quality of a service is the care with which it is provided. Changing materials for no proven advantage forces the dentist and technician to work with new techniques with which they have little experience or familiarity.

Q: Last spring my dentist advised me to replace all of my amalgam fillings for porcelain, at a cost of over $800. They are between 12-20 years old and not currently causing me any problems. Is this really necessary or are they trying to make more money off of me? The dentist says nothing lasts forever and she replaced all of my boyfriend's. He has been having sensitivity problems ever since.

I have an appointment to get half my mouth done tomorrow for $400, so any advice would be appreciated.

A: There are only two reasons to replace an amalgam filling with porcelain:

  1. You are dissatisfied with the appearance and you want it to look better, or...
  2. There is new decay or breakage, and since you want it to look better, you would prefer a tooth-colored material.

You are the only person who can decide if an improvement of the cosmetic appearance of the tooth is in order. (Composite resin restorations DO look better, and many of our patients are pleasantly surprised by the improvement in their appearance.) BUT--if the answer is no, the dentist must be able to justify the new restorations for a reason other than putting her daughter through college. If it ain't broke, don't fix it!

BTW, post-operative sensitivity under composite resin restorations is common--more so than when placing amalgams.

Q: My dentist has twice now spoken of my teeth wearing down excessively, saying she has seen better teeth in 80 year olds (I'm 51).

My wife says I used to grind my teeth at night many years ago. Perhaps this is the cause and my dentist is not noticing that the problem is not getting worse. She wants me to avoid hard food, including carrots. (I've been eating a raw carrot after every meal.)

Are there any other factors that can cause teeth to wear?

A: All teeth wear due to functional use (chewing). This loss of structural mass is progressive; tooth material that is lost is never re-grown. Abrasion and erosion can also result from para-functional habits (clenching, grinding), abnormally acidic diet, and excessively vigorous oral hygiene.

If the enamel is worn through or there is significant gum recession, softer parts of the tooth (cementum and dentin) are exposed. These softer tissues are subject to a more rapid abrasion.

It is useful to analyze any non-useful oral habits and attempt to limit them or their adverse sequellae. In the case of nocturnal tooth grinding or clenching (bruxism), oftentimes a night guard appliance can help, although they tend to be difficult to get used to. Abnormal dietary habits (there are some unusual ones out there-- sucking on lemons, gargling with vinegar, for example) should be avoided. It is not practical to engage in excessive gymnastics to modify one's diet, since it's difficult enough to practice good nutrition without worrying about one's teeth; after all, chewing healthful food is the purpose of teeth in the first place.

Sooner or later, the only practical way of managing excessive loss of tooth structure is to restore it, usually by placement of crowns. This not only reverses structural loss, but also prevents further abrasion.

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