The response of human pulpal tissue after orthodontic force application.

Previous investigations have dealt with significant alterations in pulpal respiration associated with dental materials and methods. The purpose of this investigation was to note if significant alterations in pulpal respiration remained after the insult had been removed. A rest period of 1 week was chosen to evaluate the pulpal respiration response after application of an initial 72-hour orthodontic force. A radiorespirometric method was used to determine differences in experimental and control pulpal tissue respiration rates within individuals. These data showed that the mean respiration rates of experimental pulpal tissue compared with control pulpal tissue remained depressed approximately 33.2% after the 7-day rest period. However, it was found upon further investigation that there were really two groups present--one that had returned to normal respiration rates and one that did not within a 1-week rest period. Age and apical opening size correlated with the return of the respiration rates to normal during the 1-week rest period. Age was negatively correlated with respiration rate and apical opening size correlated with the return of the respiration rates to normal during the 1-week rest period. Age was negatively correlated with respiration rate and apical opening size was positively correlated with respiration rate.