ELECTRON-MICROSCOPIC CHANGES IN HUMAN PULPS AFTER INTRALIGAMENTAL INJECTION

Because of its advantages, intraligamental injection is becoming a pop ular anesthetic technique to achieve anesthesia in vital pulps. This s tudy investigated the possible effects of intraligamental injection on human pulps under electron microscope. Forty-two mandibular and maxil lary premolars were scheduled to be extracted for orthodontic reasons after being anesthetized with intraligamental injections of 2% lidocai ne, 1:100,000 epinephrine (experimental group). The same anesthetic so lution was used on the contralateral teeth with either nerve or field blocks (control group). To examine the effects of ischemia on odontobl asts, 12 anesthetized premolars were extracted, and their pulps were p laced in physiologic saline solution for different time intervals (15 minutes to 6 hours). The teeth in the experimental and control groups were then reanesthetized with nerve or field blocks of 3% carbocaine w ithout epinephrine after time periods that ranged from 15 minutes to 2 8 days. After extraction, the teeth were sectioned vertically and thei r pulps were fixed in 3% glutaraldehyde. The odontoblastic layer of ea ch pulp was examined under electronic microscope. Nuclear and cytoplas mic changes started an hour after ischemia in the pulps placed in phys iologic saline. In contrast, little or no cellular changes occurred in pulps of the experimental or controls groups. On the basis of the res ults, it appears that intraligamental injection has no long-term delet erious effects on pulps of young human premolars.