Healing of Periapical Lesions - Breakthrough in Bacteriology

Breakthrough in Bacteriology

In 1890, W.D. Miller, considered the father of oral microbiology, was the first to associate pulpal disease with the presence of bacteria. This was confirmed by Kakehashi, who, in 1965, proved that bacteria were the cause of pulpal and periradicular disease in studies using animal models; pulpal exposures were initiated in both normal and germ-free rats, and while no pathologic changes were exhibited in the mouths of the germ-free rats, introduction of the normal oral microbial flora produced pulpal necrosis and led to periradicular lesion formation in the normal rats. The germ-free rats healed regardless of the severity of pulpal exposure, demonstrating that the presence or absence of bacteria was the determinant for pulpal and periapical disease.

Moreover, it has since been discovered that endodontic infections are polymicrobial. In fact, the bacteria present within endodontic infections are thoroughly similar to the bacteria that are involved in periodontal disease. It has also been shown that certain enzymes produced by bacteria are detrimental to the host, and can work in concert with the destructive capability of the enzymes released by dying neutrophils. Recent studies have revealed that the gene for collagenases could be detected in stains of Porphyromonas gingivalis, one of the many endodontic infective agents that are also involved in periodontal disease.

Additionally, it has been proven that a positive correlation exists between the number of bacteria in an infected root canal and the size of the resultant periradicular radiolucency.

In attempting to resolve a periapical lesion of endodontic origin, it is essential to be conscious of these principles in order to effectively combat the infection. Without proper consideration for the causes, the pulpal and periapical infection cannot be suitably treated, for effective patient management requires the correct diagnosis and removal of the cause of the infection of endodontic origin to correct the associated periapical lesion. Because periapical disease is almost inevitably preceded by pulp disease, proper chemomechanical debridement of the infected root canals, together with incision and drainage of associated periradicular swellings, will usually allow for rapid improvement in patient signs and symptoms. The same end can be accomplished by extracting the involved tooth.