Clinical significance of the length of the pterygopalatine fissure in dental anesthesia.

OBJECTIVE: This study determined the average length of the pterygopalatine fissure by using human cadavers. Recommendations are made to improve the success of maxillary nerve block injections.

MATERIALS AND METHODS: Pterygopalatine fissures were dissected, exposing the maxillary nerve trunk in 47 human cadavers. The length of the fissure was measured from the maxillary nerve to the buccal sulcus. The angle between the fissure and the occlusal plane was also recorded.

RESULTS: The average fissure length was 36.7 mm, making an approximately 60 degrees angle to the occlusal plane. Fissures from females were statistically significantly shorter than those from males. There was no difference with respect to ethnic group. Cadaver length was the best predictor of fissure length.

CONCLUSIONS: Depth of penetration with a needle that is longer than that normally available is necessary to predictably ensure a successful maxillary nerve block.