Effect of unilateral superior cervical ganglionectomy on mandibular incisor eruption rate in rats

To assess the effect of sympathectomy on rat tooth eruption, the effect of a unilateral superior cervical ganglionectomy (SCGx) on eruption rate of ip si- and contralateral lower incisors was examined. Two experiments were per formed. In a first experiment, the eruption rate of ipsilaterally denervate d incisors was similar to that of contralaterally innervated incisors, when assessed for up to 28 days after surgery. In a second experiment, under co nditions of unilateral unimpeded eruption of incisors performed ipsilateral ly or contralaterally to a unilateral SCGx, a significantly lower eruption rate of denervated incisors at the impeded eruption side, and a significant ly higher eruption rate of denervated incisors at the unimpeded side were o bserved, when computed every 2 days. Significant differences in individual Student's t tests at every time interval occurred mainly during the first a nd the last week of examination. When average daily eruption rate was compu ted in weekly intervals, a significant interaction between SCGx and the sid e of impeded or unimpeded eruption was found in a factorial ANOVA, that is, for each of the 4 weeks of examination, sympathetically denervated incisor s showed lower eruption rates at the impeded eruption side, and higher erup tion rates at the unimpeded side. These results indicate that incisor erupt ion is not modified by a local sympathetic denervation unless the contralat eral lower rat incisor is cut out of occlusion. (C) 2001 Elsevier Science B .V. All rights reserved.