Comparison of One versus Two Appointments Endodontic Therapy on Healing of Periapical Lesions in Dogs, Teeth

Statement of Problems: Apical periodontitis is caused by bacteria within root canals. Logically, the treatment of apical periodontitis should be directed to the removal of the cause, i.e bacterial eradication. The best procedure for disinfection is canal debridement and irrigation during the first appointment, followed by the application of calcium hydroxide dressing for one week. MTAD, a Mixture of Tetracycline isomer, Acid and Detergent is a new antibacterial solution which has been claimed to be useful in one visit treatment. The purpose of this study was to compare healing of periapical lesions after one visit treatment using MTAD with two appointments endodontic therapy by calcium hydroxide in dogs teeth. Forty incisor and first premolars of four dogs were left open for four months until periapical lesions developed. Twenty root canals were treated endodontically using MTAD in one visit, and the other 20 canals were dressed with calcium hydroxide for 1 week, and endodontic treatments were then completed. Six months after treatment the dogs were killed by vital perfusion. After fixation, the teeth were histologically examined for the healing of periapical lesions. Kruskal-wallis and Mann-Whitney tests were used for statistical analysis. The percentage of healing, advanced organization, organization, and acute inflammation for MTAD group were 31.6%, 26.3%, 36.8%, and 5.3%, while for calcium hydroxide group they were 16.7%, 16.7, 55.6%, and 11.1% respectively. The difference between the two groups was not statistically significant (p>0.05), but healing of lesions progressed better in MTAD group. One-visit treatment by use of MTAD for pulpless teeth with periapical lesion is an acceptable alternative therapy to two-visit treatment using calcium hydroxide.