Effects of Current and Potential Dental Etchants on Nerve Compound Action Potentials

Abstract

In this study, a 35% phosphoric acid gel (3M Scotchbond etchant), a nonrinse etchant (NRC), and two EDTA-containing conditioners (RC-Prep and File-Eze) were tested in vitro for blocking nerve conductance evoked in the rat sciatic nerve after local application. The phosphoric acid gel and NRC completely and irreversibly inhibited conductance. On the other hand, RC-Prep reduced the compound action potentials (cAPs) by 50% in 120 min. With File-Eze, the reduction in cAPs was less than 50% after an application time of 160 min (61.8 +/- 1.8%). At 160 min the cAPs in the RC-Prep group had been inhibited by 62.4%. These results indicated strong neurotoxic effects of phosphoric acid and NRC when applied directly on exposed pulp in the total etch procedure.

Effects of machined/turned, TiO2‐blasted and sandblasted/acid‐etched titanium oral implant surfaces on nerve conduction: A study on isolated rat sciatic nerves

“…The bath contained Tyrode solution (8 g/l NaCl, 0.2 g/l KCl, 0.2 g/l CaCl 2 , 0.1 g/l MgCl 2 , 1 g/l NaHCO 3 , 0.05 g/l NaH 2 PO 4 , 1 g/l glucose) continuously gassed with O 2 and CO 2 (95% and 5%, respectively). 27,30,31 The pH was 7.4 and the temperature was kept constant at 37°C throughout the experiments. The nerves were continuously perfused with Tyrode solution at a rate of 2 ml/min at 37°C.…”

“…27,30,31 During all experiments, the percentage amplitude of the cAPs versus time diagram was plotted. 27,30,31 Machined/turned-surface commercially-pure titanium (cpTi) implants (Nobelbiocare, Göteborg, Sweden), TiO 2 -blasted cpTi implants (Astra Tech, Mölndal, Sweden), and SLA-surface cpTi implants (ITI, Straumann Institute, Waldenburg, Switzerland) were used in this study. Each group consisted of three implants, and were tested on sciatic nerves obtained from a total of nine animals [Figures 2(a) and 2(b)].…”

Inhibition of compound action potentials following administration of dental self-etching primer/adhesives

“…Since one major reason for the use of etchants in the total etch procedure is to open up dentin tubules which have been previously occluded by the smear layer, the ability of the etchant to modify or block the nerve transmission could be considered a valuable compensation for the hydrodynamic forces it will allow to occur. However, in a recent study which showed neurotoxic potential of strong dentin conditioners such as 35% phosphoric acid [19], it was speculated that the acid would presumably not be able to alter the composition of the dentinal fluid in a single application, especially when applied to intact dentin which is a relatively indirect access to the pulpal nerves. Thus, the authors concluded that the time-course of the blocking effect in clinical use may be longer than that achieved within the limitations of their study, since there seems to be no way dentin conditioners could be titrated or applied in such a way as to just balance these two opposite effects to reach the desired clinical result [19].…”

“…However, in a recent study which showed neurotoxic potential of strong dentin conditioners such as 35% phosphoric acid [19], it was speculated that the acid would presumably not be able to alter the composition of the dentinal fluid in a single application, especially when applied to intact dentin which is a relatively indirect access to the pulpal nerves. Thus, the authors concluded that the time-course of the blocking effect in clinical use may be longer than that achieved within the limitations of their study, since there seems to be no way dentin conditioners could be titrated or applied in such a way as to just balance these two opposite effects to reach the desired clinical result [19]. Based on this discussion, it does not seem that there is a way in which the relatively weaker acids in FL Bond, SE Bond and Mac Bond could have contributed to the rapid inhibiton of the CAPs in the present study [8].…”

Effects of Ankaferd Blood Stopper on Nerve Conductance: An experimental study on the Rat Sciatic Nerve

“…During all experiments, the percentage amplitude of the cAPs versus time diagram was plotted. 8,[10][11] After the completion of each experiment, the tested nerve was discarded and a fresh nerve was used for the upcoming experiment. The first set of 6 sciatic nerves was used for control group and tested for 100 min at 10 min intervals.…”