Louis R. Marion, DMD, MS, LLC - Prosthodontics
Blog Entry (week of 3/8/10):
Should my mouth be metal free?
Many friends and patients ask me this. 
There are two categories to this question.  The first has to do with fillings.  Fillings can be silver, gold, or tooth-colored.  The most common today are tooth-colored in the form of composite resin.  Composite resin fillings consist of a resinous matrix of particles that can match the shade of your tooth.  These fillings or restorations can be beautiful.  They are light-cured or bonded to teeth via mechanical and chemical processes.   Gold and amalgam are more traditional filling materials.  Amalgam is in much more common use than gold and is an matrix of silver particles mixed with metals like copper and zinc.  It uses a mercury matrix to become soft so it can be inserted in a cavity preparation.  Although the mercury is toxic, the ADA and FDA have not found it significantly harmful to the human body in this form.  There is a risk that removing these fillings for no other reason except esthetics can be detrimental to your teeth.  My conclusion is that in an ideal setting, composite resin can be a great restorative material.  In an area underneath tissue, metal is better because composite fillings need to be placed in a dry area; therfore, they cannot succeed long-term if they are placed in a wet area.   --> A good dentist should base this choice on the patient's health, not their insurance, wallet, or fear of toxicity.
The second part of the question has to do with crowns and bridges.  Crowns and bridges can be produced today without any metal.  Dental laboratories can work with dentists to create all-ceramic, beautifully looking crowns and bridges.  However, ceramic is both hard and brittle.  It neither has the same elasticity as tooth structure nor  the same flexural properties.  Therefore, they do not have the same longevity as crown and bridges with metal.  In my opinion, materials for a patient's crown or bridge should be selected on a case-by-case basis.  Ceramics are strong and do well on anterior and most posterior teeth.  Metal does better in posterior areas and, especially, in long-spanning bridges. 
Tip of the day (week of 3/1/10):  
If you have to make a choice between an after-dinner mint or after-dinner piece of gum, choose the gum.  
Following a meal, the pH in your mouth becomes more acidic.  Saliva, that buffers the mouth's environmental pH to be more normal to protect teeth, was used to help digest and swallow your food.  The lower volume of saliva after a meal leaves the enamel, the outer structure of teeth, susceptible to break down in the presence of bacterial acids.  This leads to decay.  A hard candy like a mint, gives bacteria what they need most to destroy your teeth -- sugar or energy.  Chewing gum, however, stimulates new salivary production, thereby improving your mouth's ability to buffer the pH and prevent decay.
Coming Soon: Dr. Marion will continue to express his views, review his recent lectures, and discuss debates regarding controversial issues in dentistry, nutrition, and anthropology.
Louis R. Marion, DMD, MS, LLC
1500 Locust Street, Suite 1416
Philadelphia , PA , 19102 USA
Phone 2157325110
Mobile 2156689072
Fax 2157329938