No – abfraction has nothing to do with those pesky arithmetic problems that we solved in school. It is a phenomenon that happens along the cervical area of a tooth. The cervical area is along the gum line. An abfraction lesion is a “V” shaped notch in the tooth that forms along the gum line. It was previously thought that these cavitations were caused by overly aggressive tooth brushing or by leeching out through chemical erosion, it is now postulated that forces of the bite will cause the tooth to flex causing tiny cracks to form over the years eventually forming the classic “V” furrow. There are no studies at this time which prove beyond a shadow of a doubt that these wedge formations were caused by biting forces, however, it comes the closest to explaining a phenomenon that can’t be caused by tooth brushing alone. These cavitations can be observed for a while, but they should be restored before they get too deep. By rounding out the “V” shaped notch during the cavity preparation, biting forces will be more evenly distributed, helping to slow the process. Due to tooth flexion during chewing, fillings placed in these areas tend to need to be replaced more often.
Monthly Archives: April 2013
How Does a Porcelain Laminate Stay in Place?
Porcelain laminate veneers are a wonderful way to conservatively change the shape and color of teeth with a durable long-lasting restoration. The laminates are extremely thin (thinner than finger nails) veneers of porcelain. They are held in place by a bonding resin cement. The word “bonding” is somewhat of a misnomer as there is very little true adhesion involved. The enamel surfaces of the teeth and the inside surface of the porcelain are etched with an acid solution. This creates microscopic crevasses in those surfaces. A liquid plastic is flowed over these areas and filters down into the tiny crevasses. The plastic is then hardened with the rest of the cement with an intense light source. A silanating agent that has double bonds for porcelain and the resin cement will provide some mild adhesion for that interface and the new generation dentin bonding agents will also help adhere to areas where the dentin , the inner layer of the tooth, shows through. The resin cement can also help with the color of the tooth. The cement is naturally translucent, however, different agents can be added that can change the color and the opacity of the laminate, thus masking any problems with the underlying teeth.