Fillings and sealants.

Alternatives to amalgam

Advances in dental materials and techniques increasingly offer new ways to create more pleasing, natural-looking smiles. Researchers are continuing their often decades-long work developing esthetic materials, such as ceramic and plastic compounds that mimic the appearance of natural teeth. As a result, dentists and patients today have several choices when it comes to repairing missing, worn, damaged or decayed teeth.

The advent of these materials has not eliminated the usefulness of the more traditional ones, which include gold, base metal alloys and dental amalgam. Their strength and durability continue to make them useful where a restored tooth must withstand the extreme forces of chewing, such as at the back of the mouth.

Alternatives to amalgam are more expensive. Gold and porcelain restorations take longer to make and can require two appointments. Composite resins, or white fillings, are esthetically appealing but take longer to place.

Composite fillings

A mixture of acrylic resin and finely ground glass-like particles that produce a tooth-coloured restoration. Composites give good durability and resistance to fracture in small to mid-size restorations under moderate chewing pressure. Less tooth structure is removed when the tooth is prepared, so the filling can be smaller than an amalgam would be, and composite can be bonded into the cavity, which allows a more conservative repair. Where chewing loads are high they are less resistant to wear than silver amalgam.

Glass and resin ionomers

Tooth-coloured materials made from acrylic acids and fine glass powders, used particularly on the root surfaces of teeth. Glass ionomers release a small amount of fluoride, which helps patients at high risk of decay. Because they have a low resistance to fracture they are used mostly in small, non-load-bearing fillings between the teeth or on the roots. Both types mimic natural tooth colour but lack the translucency of enamel, and both are well tolerated, with only rare allergic response.

Porcelain and ceramic

All-porcelain materials are used as inlays, onlays, crowns and aesthetic veneers. They are particularly desirable because their colour and translucency mimic natural enamel. They require a minimum of two visits and sometimes more. They are prone to fracture under tension or impact, and their strength depends on an adequate thickness of porcelain and on being bonded to the tooth underneath. They are highly resistant to wear, though a porcelain surface that becomes rough can wear the opposing tooth quickly.

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Sealants

Research has shown that almost everybody has a 95 percent chance of eventually experiencing cavities in the pits and grooves of their teeth. Sealants work by filling in those crevasses on the chewing surface, which shuts out the food particles that would otherwise get caught there. The application is fast and comfortable and can protect teeth for many years. Research has shown that sealants actually stop cavities when placed on top of a slightly decayed tooth, by sealing off the supply of nutrients to the bacteria causing it.

Sealants are best suited to the permanent first molars, which erupt around age six, and the second molars, which erupt around age twelve. They are most effective applied as soon as the tooth has fully come in, which is why children derive the greatest benefit: more than 65% of all cavities occur in the narrow pits and grooves of a child’s newly erupted teeth.

How they are applied

The surface of the tooth is cleaned and rinsed to remove all traces of the cleaning agent. An etching solution or gel is applied to the enamel, including the pits and grooves. After fifteen seconds it is thoroughly rinsed away with water. The site is dried, the sealant material is applied, and it is hardened with a curing light.

Sealants normally last about five years and should be examined at every regular checkup. Insurance coverage for them is increasing but still minimal, a trend many dentists expect to change as insurers become more convinced that sealants reduce future dental expense.