Effects of gingival retraction materials on gingival blood flow.

PURPOSE: The effects of 2 chemical retraction agents on gingival blood flow and systemic blood pressure in subjects with healthy gingiva were investigated. MATERIALS AND METHODS: Thirty volunteer dental students were selected for the study and randomly divided into 2 groups. Aluminium chloride-impregnated cord (right side) and nonimpregnated cord (left side) were placed in the gingival sulcus of group 1. Epinephrine-impregnated cord (right side) and nonimpregnated cord (left side) were placed in group 2. Blood flow in the retracted marginal gingiva was measured by laser Doppler flowmetry, and the systemic blood pressures of subjects were recorded before and after the retraction procedure. RESULTS: A statistically significant decrease in blood flow was observed in group 2, but there was no significant change in gingival blood flow in group 1. A decrease in diastolic blood pressure of the subjects in group 2 was also observed. However, there was no significant change in blood pressure of the subjects in group 1. CONCLUSION: Gingival retraction affects gingival blood flow temporarily. Epinephrine-impregnated cords can be used safely in patients who have healthy gingiva, if patient stress and gingival trauma are avoided during cord placement.

The sources of laser Doppler blood-flow signals recorded from vital and root canal treated teeth.

OBJECTIVES: The aim was to determine the strength of signals derived from the dental pulp and those from the surrounding tissues in human teeth using the laser Doppler flowmetry (LDF). METHODS: Twenty-six vital teeth (13 experimental and 13 controls) from 12 patients were used. Experimental teeth had root canal treatment in a single visit and their healthy antimeres were controls. Blood flow measurements were made before and after local anaesthesia, after root canal preparation, following root canal filling and coronal restoration. RESULTS: Perfusion unit (PU) values recorded from empty pulp chamber were determined to be only 30% lower than the values recorded before anaesthesia from the experimental intact teeth. When the measurements in the group were compared with each other the values of variation in the both groups were not statistically significant. The variation between the groups when the measurement values before anaesthesia, 10min after anaesthesia and after coronal restoration were compared, it was not statistically significant (P>0.05). The variation between the groups after preparation and root canal filling in their values of measurements was important statistically (P<0.05). The measurement values of the study group were lower than that of the control group. CONCLUSIONS: In pulpal, LDF a major portion of the signal comes from tissues other than pulp. Without taking precautions (such as rubber-dam application) in pulp blood flow measurements, the results may be inconsistent.