Effect of full crown preparation on pulpal blood flow in man

• Pulpal blood flow was recorded in bridge abutment teeth.
• Blood flow was monitored before and for up to 7 days after crown preparation.
• Recordings were made with a laser Doppler flow meter.
• An increase in blood flow would indicate inflammation.
• Crown preparation caused no increase in blood flow in any of the teeth.

ObjectiveTo determine if full crown preparation causes an increase in pulpal blood flow (PBF), indicating inflammation, in human subjects.DesignThe experiments were carried out on 35 intact, mandibular posterior teeth in 13 subjects: 32 were abutments for 16 fixed bridges that replaced first molars; the other 3 were first premolars adjacent to abutment teeth that served as un-operated controls. Crown preparations were made using an air-rotor with water-spray under regional block anaesthesia (4% articaine with epinephrine 1:100,000). PBF was recorded with a laser Doppler flow meter (LDF) before and after administering the anaesthetic, with the LDF probe on the buccal enamel. PBF was then recorded from the abutment teeth with the probe on buccal dentine after preparing the buccal surfaces of both teeth, after completing the crown preparations, and after 1 and 7 days. PBF was also recorded from the buccal enamel of the control teeth on each occasion.ResultsThe mean ± S.D. PBF values before and after anaesthesia were 2.63 ± 2.13 and 2.42 ± 2.38P.U. respectively, which were not significantly different (Paired t-test). The mean values for the abutment teeth after buccal preparation, after complete crown preparation, and after 1 and 7 days were 5.20 ± 2.49, 4.53 ± 2.52, 4.92 ± 2.98 and 5.48 ± 2.65P.U. respectively. The 4 values for each tooth were not significantly different (two-way RM ANOVA). In the control group, the values under all six conditions were not significantly different.ConclusionsRegional block anaesthesia produced no change in PBF, nor did full-crown preparation, neither immediately after the procedure nor 1 and 7 days later.