(PR91) An Animal Study to Exclude the False Positive Response of Ultrasound Doppler Flowmetry in the Diagnosis of Tooth Vitality

The purpose of this study is to evaluate the effect of adjacent gingival blood flow on detection of pulpal blood flow (PBF) using ultrasound Doppler flowmetry (UDF) in animal models and to consider how UDF can be effectively applied to tooth diagnosis. Pulse sound level (PSL) was recorded using an UDF device (MM-D-K; Minimax, St. Petersburg, Russia) on maxillary third incisors, maxillary canines, mandibular canines, and mandibular third premolars of six experimental dogs, after each of the following procedures: tooth without flap elevation (Group 1), gingiva (Group 2), gingiva isolation with light curing resin barrier (Group 3), tooth with flap elevation (Group 4), after pulpotomy (Group 5), and after canal filling (Group 6). In Groups 5-6, the study was performed with flap elevation. PSL was graded as follows: 0, inaudible; 1, ambiguous; and 2, definite. The difference between each group was analyzed using Friedman’s test with Wilcoxon signed-rank tests. A total of 37 teeth were included in this study. The PSL results were Group 2 >1³3,4,5>6. In Group 2 the PSL was very definite. Group 3-5 were similar. In Group 3 the light curing resin barrier made PSL and wave patterns weaker, producing a gingiva isolation effect similar to Group 4. In Group 6 sound was almost inaudible. PBF is affected by gingival blood flow when measured with UDF. Isolation of gingiva will increase the accuracy of detecting PBF limited to the tooth.