Effects of intrusive force on selected determinants of pulp vitality

Abstract

Objective: To determine the activity of aspartate aminotransferase (AST) in the pulp of orthodontically intruded teeth and to test the sensitivity of these teeth by means of electrical pulp testing(EPT). Materials and Methods: The study sample consisted of 21 healthy subjects who needed extractionof first premolars for orthodontic reasons. In every subject, one premolar included in a 0.016"0.022" stainless steel spring from the first molar and loaded by the force was regarded as a testtooth. The magnitude of the intrusive tipping force for every tooth was calculated with the use of ANSYS 10.0 software. The contralateral premolar was used as a control tooth. After 7 days, thespring was removed, and EPT was applied to test and control teeth. The teeth were extracted,and the dental pulp was removed. AST activity in the pulp was determined spectrophotometricallyat 20°C. Results: Estimated mean AST activity values ranged from 0.572±0.097 U/mg in the test teethto 0.348±0.053 U/mg in the control teeth (P