The changes of anterior teeth pulp vitality and pain during orthodontic treatment

Abstract

Objective To explore the changes of anterior teeth pulp vitality and pain during orthodontic treatment. Methods 24 adolescent patients seeking for fixed orthodontic treatment were selected. The pulp vitalities of anterior teeth were periodically evaluated using digital electric pulp tester to test the responsive threshold to electric stimuli (EPT). The severities of pain during orthodontic treatment were evaluated using a visual analog scale (VAS). There were 13 evaluation time points: O represented the baseline before treatment; A1-A3, B1-B3, C1-C3 and D1-D3 represented four different treatment stages using four types of nickel-titanium archwires (0.012 inch, 0.016 inch, 0.016×0.022 inch and 0.018×0.025 inch) respectively. Each stage included three time points: 1-immediately after archwire engagement, 2-72hrs after engagement, and 3-immediately before archwire removal. Results During orthodontic treatment, the EPT mean values at time points A1-D3 were significantly higher than that at pre-treatment time point O (P 0.05). Regarding the VAS scores in each archwire stage, the scores at A2, B2, C2 and D2 were significantly higher than the other two time points (1 and 3) within the same stage. Besides, the score at A2 was significantly higher than that at B2, C2 and D2 (P<0.05). Conclusions The pulp of anterior teeth was less sensitive to electric stimulus during orthodontic alignment and leveling process. The pulp vitality of anterior teeth significantly decreased after the engagement of the first archwire; however, no significant change of pulp vitality was found during the subsequent sequential removal and engagement of archwires. The VAS pain reached the peak at three days after first archwire engagement and fluctuated periodically afterwards; it increased at the third day of each replacement of archwire and then relieved gradually. Key words: Orthodontic force; Dental pulp; Pulp vitality tests; Orthodontic pain