Histologic response to intraligament injections using a computerized local anesthetic delivery system. A pilot study in mini-swine.

BACKGROUND

Intraligamentary (periodontal ligament) injection has been used to locally control pain with minimal anesthetic dose. The purpose of the present study was to determine the histologic effect of using a computer-controlled local anesthesia delivery system (CCLADS) for the administration of a periodontal ligament injection in the mini-swine model system.

METHODS

Thirty-two sites in 3 mini-swine pigs with healthy periodontium were selected. Each site was notched on the mesial-lingual line angle of the tooth to allow a reference for needle placement and provide a histologic marker. An anesthetic cartridge was used with a 30-gauge needle attached to the handpiece of the CCLADS. This provided a controlled flow rate for 2 minutes. The control sites were treated with the same needle in place for 20 seconds. The animals were sacrificed and provided observation periods of 1 hour, 1, 4, 7, 21, and 49 days. Specimens were stained with hematoxylin and eosin and trichrome.

RESULTS

Twenty-four hours after injection, limited localized inflammation was present. By 7 days, the ligament appeared within normal limits. Apical migration of the junctional epithelium extended to the apical limit of the notch and was similar in test and control specimens.

CONCLUSIONS

Within the limits of this study, the histologic results showed that tissue responses following intraligament injections using a CCLADS demonstrated limited inflammatory responses within the first 24 hours, which abated by 7 days postinjection. Similar migration of the junctional epithelium was seen in test and control specimens and was probably related to tooth injury rather than anesthetic injections. Further investigations are warranted using CCLADS to determine whether clinical benefits will translate in the human model system.