DENTISTRY 5 Enamel infraction Enamel infractions, also called craze lines, are incomplete fractures (cracks) of the enamel without loss of tooth structure. No treatment is indicated. (Figure 8) Figure 8. An enamel infraction affecting the right mandibular canine. 7 Enamel fracture These fractures are confined to the enamel. Because dentin is not exposed, enamel fractures are not considered painful. To protect the tooth from further damage, treatment should include smoothing any sharp enamel edges with a high-speed handpiece and applying a composite or metallic restoration (Figures 10A-10C). The enamel on cat teeth is thinner than in dogs. Because of underlying sensitivity and infection, enamel fractures in cats should be treated by extraction or root canal therapy. Figure 10A. An enamel fracture approaching the underlying dentin in a dog. 6 Enamel hypomineralisation This condition occurs when there is an inadequate mineralisation of enamel matrix. It can affect several or all the teeth. The crowns of affected teeth are covered by soft enamel that may flake off during ultrasonic scaling and are worn rapidly during daily chewing. Treatment is the same as that for enamel hypoplasia (Figures 9A and 9B). Figure 10B. Phosphoric acid used as an etchant before applying light-cured composite. Figure 9A. Enamel hypomineralisation of the left mandibular canine and incisors Figure 9B. Enamel hypoplasia and hypomineralisation. Issue 06 | DECEMBER 2016 | 10 Figure 10C. The restored canine tooth.