Clinical study of the innervation of the anterior hard palate
Description
The conventional nasopalatine nerve block (NPNB) is commonly used to obtain anaesthesia in the anterior portion of the palate. Unfortunately, NPNB cannot always yield a satisfied anesthesia effect at the palatal gingiva of anterior teeth, which reflects the controversy about the innervation of this area and the distribution of nasopalatine nerve. The present research was designed to study the innervation of the anterior part of hard palate (AHP) in patients of different ages. 182 children with mixed dentition and 219 patients with permanent dentition who were indicated to local anesthesia during treatment were included into this study. Patients in mixed dentition were randomly divided into group A1 and group A2, and received NPNB or bilateral greater palatine nerve block (BGPNB) respectively. Patients in permanent dentition were divided into adolescent group (range 13-18 years) and adult group (over the age of 19 years), and all accepted BGPNB. Using Von Frey hairs, the anesthetic efficiency were examined by testing the pain sensation of the palatal mucosa pre- and post-anesthetically. All the data were analyzed by Student's t tests and Pearson's chi-square tests. For children with mixed dentition, BGPNB was likely to result better anesthesia at the AHP than NPNB did (p<0.05), except the incisive papilla, in which the anesthetic effect of the NPNB was significantly superior to that of the BGPNB. Meanwhile, BGPNB was found more effective for anesthesia of AHP in children than that in people with permanent dentition, i.e., adolescents and adults (p<0.05). However, there was no significant difference in anesthetic effect of AHP between adolescent and adult. The results of present study indicated that the sensation of anterior hard palate is mainly dominated by the greater palatine nerve in childhood and gradually shifts to nasopalatine nerve accompanied with the development of maxilla and tooth replacement. It seemed that the nasopalatine nerve undergoes a process of secondary development through adolescence. Such converting of innervation should be accounted in local anesthesia of AHP area.