Enamel hypoplasia in permanent teeth induced by periodontal ligament anesthesia of primary teeth.

Periodontal ligament anesthesia was applied to 16 primary teeth in jaw quadrants of two monkeys. The teeth in the contralateral positions were not injected and the permanent teeth in this area served as controls. The animals were killed after 22 months when the permanent incisors began to erupt. In total, enamel hypoplasia or hypomineralization (or both) was noticed in 15 permanent teeth in the experimental quadrants but in none of the controls. The results strongly emphasized that periodontal ligament anesthesia should be used with great care on primary teeth close to developing permanent teeth.