BUILT TO LAST

Last month I presented the basic disease processes involved in dental cavities and periodontal disease.  This month I will discuss some strategies for prevention and some options for repair.

Remember that teeth are crystals and crystals dissolve in acid.  So a major strategy in preventing cavities is to effectively control the acid levels in our mouths.  We know we all eat and drink things that increase our cavity risk – how can we counterbalance that? (Because we know we’re unlikely to give it up ;^)  Here are a few simple things to consider:

1)  Drink water.  Anytime we eat anything that contains sugar, and just about everything does, take a sip of water.  Water will dilute whatever acids are present or being produced.  Also, swish the water around.  This will have a rinsing effect that will help remove larger food particles, getting them out of your mouth where they cause damage and into our stomachs where they provide nutritional benefit.  Sounds simple, but it works.

2)  Chew xylitol based gum.  Xylitol is a non-fermentable sugar, which means that the bacteria in our mouths cannot metabolize it, so they do not produce acid.  Also, the xylitol will stunt bacterial growth and multiplication.  Chewing gum also provides salivary stimulation and mechanical cleaning of food debris from our teeth.  Saliva not only dilutes and washes away acids, it also contains important buffering components that help to neutralize acid in our mouths.  Gum sticks to food particles and pulls them out from in between teeth and out of the grooves of back teeth.  This helps keep teeth healthy because if there is no food on the teeth, there is no food source for bacteria to create acid.

3)  Use fluoride.  I know people debate the use of fluoride and it can be a controversial topic.  My purpose here is not to debate fluoride.  It is to simply state what it does when used properly.  There are two aspects to fluoride administration as it relates to teeth, systemic and topical.  An example of systemic fluoride would be fluoride tablets that children take.  The idea here is that as teeth develop, they will do so with fluoride as part of their crystalline structure.  This is desirable because when fluoride is part of the crystal structure of teeth, a stronger acid is required to dissolve that crystal structure in order to create a cavity.  However, if used in excess, fluoride will discolor and can actually weaken teeth.  And so it must be used with prudence and good judgment.  An example of topical fluoride use is fluoride-containing toothpastes.  Think of crystals as batteries – just as a battery can lose charge and be recharged, crystals can dissolve and re-crystallize.  In fact, in our mouths where acid levels are constantly fluctuating, our teeth are continually dissolving and re-crystallizing.  By having fluoride in our toothpaste, it adds a building block to help crystals re-form and it makes them resistant to dissolution as a stronger acid is needed to dissolve the crystal.  Again, these toothpastes must be used with good sense so as not to “overdose” on fluoride.

There are many ways to repair a tooth or teeth.  Everyone is familiar with fillings, which can be made of amalgam (“silver fillings”) or composite.  Amalgam has been successfully used for many years as a filling material.  As with fluoride, there is considerable debate about amalgam.  It also is quite noticeable in someone’s mouth and so many patients prefer a tooth colored option.

Composite fillings have also been used with success for many years.  While the material itself is not quite as durable as amalgam filling material, many prefer this material as it does not have the controversy surrounding it that amalgam does and because it is tooth colored.  In fact, it comes in many different shades and can be matched precisely to the surrounding tooth so that teeth with fillings do not appear to have fillings at all!

Sometimes a tooth has been so damaged that it requires a more durable type of restoration.  Engineers are very familiar with the limitations of the various materials they use.  When forces will overload a certain material, an engineer will select a stronger, more suitable material to withstand the loads that will be placed upon it.  Similarly, very large fillings in teeth tend to fail more quickly because the structure of the tooth is compromised and the material itself is not designed to withstand forces involved with restoring the majority of a tooth’s structure.  In these cases a “cap” or a crown is recommended for a tooth to restore its natural contours and function in a durable, predictable manner.

Crowns come is three basic types – all gold, porcelain fused to gold, and all porcelain.  In terms of durability, gold has the best and longest track record.  However, it costs more and it looks gold, which can be a cosmetic concern for some.  Porcelain fused to gold provides patients with a tooth colored, durable alternative to gold.  While the porcelain can sometimes break during chewing, these crowns have a long track record of serving patients well.  An all porcelain crown will typically provide the best esthetics and many of the newer porcelains are rivaling the traditional porcelain fused to gold crowns in terms of durability and fit.  However, all porcelain crowns have historically demonstrated a higher fracture rate than the other crown types.

With any restoration, patients will often ask, “How long will this last?”  The answer to this question has at least two variables.  First is, how well is the restoration made?  It is the responsibility of the dentist to provide a well-made filling or crown.  What does this mean?  For a tooth colored filling it means that the dentist maintained an adequate dry field during placement of the filling, that s/he followed the manufacturer instructions for the materials used (bonding agent, composite, curing light, etc.), that properly sealed margins (where the tooth and filling join) were created, and that appropriate contours were created (bite is correct, contacts with adjacent teeth are touching and allow floss to pass through, emergence profile is correct, etc.).  For a crown it means the tooth is prepared with appropriate retention and resistance form, that proper ferrule is present if needed, that the crown itself fits accurately on the tooth (no “open margins” or “overhangs”), that the adjacent teeth touch with the correct amount of pressure, that correct emergence profile is present, and that the bite harmony has been maintained.  The dentist must do a quality job.

Second is how well the restoration is cared for.  It does not matter if a restoration is made to the highest standard if it is not properly cared for.  It is not unusual to see a poorly made restoration last longer than a well made one because it is well cared for.  A patient must engage in daily oral hygiene practices (brushing, flossing, etc.), make smart diet choices to manage the acid balance in his/her mouth, and return for regular dental visits to maintain oral health.

Everyone has teeth.  Everyone has dental needs.  Our goal is to help people manage their health such that maintenance will be their only need.  Some come with years of neglect and require a lot of corrective treatment before they get to the maintenance stage.  Nevertheless, it is at the maintenance stage of oral health that patients feel better, are happier with their health, and liver fuller lives.