Metal-Free Restorations

No Metal Restorations | Marin Health and smilesThe bacteria must be kept out of the tooth with the controlled placement of bonding agents that create the hermetic seal. Again, a dental dam is important here, to prevent saliva contamination and aid the bonding process.

If all these steps are taken, caries is ‘completely’ removed, and a good seal is accomplished, fillings are very comfortable and durable. You can expect eight to ten years of service from composite fillings, but we often get much longer results, and believe it is due to the great care we take in the process.

For teeth that are more extensively broken down, metal free restoration have advantages and disadvantages. Porcelain materials and more recently zirconia are the current popular materials. These are oxides of aluminum and zirconium. These materials are not technically metal free, but in their oxidized forms these metals are more inert and less reactive. They are less expensive and look absolutely lifelike and natural. They are very bio-compatible with gum tissue.

On the downside, all porcelain and zirconia crowns are too new to know how long they will last. All the manufacturer studies are flawed, because the materials are changing very quickly, and so there are no long-term studies available with the best all porcelain materials available today. We do know they are relatively weak and prone to fracture. This fact explains the continuing effort by manufacturers to improve the materials.

The newest generation of all porcelain material is now strong enough to be very useful in low stress areas on front teeth. But in molars the strength becomes an issue. To compensate for their lack of fracture resistance, they must be made thicker for use in molars, which means more tooth structure must be taken away. The final restoration must be the same height, so the extra thickness must come at the expense of the tooth, requiring a deeper cut into the tooth that puts the nerve at risk, particularly with short and small teeth. The deeper cut into the tooth also takes away more of the enamel outer shell of the tooth, which makes bonding less reliable. Because these materials are dependent on bonding to hold them in place and seal the tooth, this is a serious problem for long-term success. De-bonding and fracture are the most common problems with these materials, which leads to early failure and increases the risk of root canal therapy.

All porcelain materials also cause accelerated wear on teeth in the opposite arch, the teeth they chew against. This is related to the hardness of porcelain. It is much harder than natural tooth structure, and will often wear through the enamel of the opposing teeth in contact when chewing or clenching. Over time this can lead to an imbalanced bite, shifting and unsightly wear of teeth, and ultimately more complex dentistry.

Because of the significant downside or using these materials, they must be used very cautiously, only in the right circumstances to manage the disadvantages and with the knowledge that they have significantly higher risks than gold alternatives that can be made thinner and are much stronger and have a proven track record.

Gold is still the standard in durability and bio-compatibility, with more than 93% lasting more than twenty years! Gold does not create a wear problem with opposing teeth. It wears like natural tooth. Because it is so fracture tough, it can be made thin and is much more conservative, not requiring deep cuts into the tooth and thereby saving tooth structure. And that helps to avoid root canals.

We will work with you to help you make the right choice for your mouth. Because we routinely work with all these materials we can guide you through the appropriate alternatives and come up with a plan that is right for you.