Go Direct to the Novum Implant Explanation

Word of Mouth

Fractures in Posterior Teeth

Stephan Eakle Journal of the American Dental Association Vol. 112 Feb.

Fractures are common, advances in dental science are helping people retain teeth longer, but teeth are subjected to many physical stresses. Weakened states can lead to complete or partial factures.

Laboratory studies show wide fillings weaken teeth. No fillings or small fillings means less chance of fracture. Cameron reported most factures in patients 50 years or older.

Snyder found most fractures in subjects aged 30 to 59 years. Some studies show the first lower molar the most frequent, other reports indicated the second lower molar. One study of root filled teeth showed 70% of teeth had fracture of the supporting cusps. Another study showed the most frequent cusp fracture on the first lower molar’s ‘ rear on the tongue side’. The second most frequent was the upper 4th tooth from the center, outside cusp.

Results

In examining 206 fractures, researchers found that:

• The average ages was 37 years.
• In the lower jaw 88% o fractures were within molars, in the upper jaw, molar fractures were equal to bicuspid fractures.
• All first molars fractured more frequently tan second molars 70% compared to 26%
• 5% of lower molars fractured front to back
• 53% of all fractures were above the root
• 31% fractured onto the root
• 15% fractured below the gum and bone
• 18% involved the pulp of all fractured teeth,
• 91% had been filled before

Cameron believed teeth become brittle with age but this study shows most below 40 years of age and predisposing factors of worn cusps, steep sharp cusps working against deep grooves, large fillings, high spots on fillings or teeth, and bruxism or grinding of teeth should be the main consideration in deciding when to use a cusp protective casting… protective treatment should be offered to younger patients instead of large amalgams when predisposing factors exist indicating risk of fracture. Bell concluded small cracks extend under repeated loading and than large amalgams do not support cusps, which tend to bend outwards under loading. Forces are 10 times greater in the corner of a cavity.

Isolated teeth will be subjected to greater force because they cannot share the load with neighboring teeth.

94% of fractures occurred when the filling was greater than 1/3 the width of the tooth.

Conclusion:

Dentists can help prevent tooth fractures by providing cusp protection when predisposing factors indicate there is a significant risk for fracturing.

Back to Word of Mouth