Objective      To evaluate the sealing ability of iRoot SP (a bioceramic material) in root canal obturation with a quantitative method using glucose and micro-computed tomography (micro-CT).       Methods      Fifty-five mandibular premolars with single root canal were decoronated to obtain 12-mm root segments. The root canals were instrumented using Protaper Files prepared to 30#. The roots were randomly divided into 3 experimental groups A

B and C (n=15)

a negative control group D (n=5)

and a positive control group E (n=5). The root canals of group A were directly filled with iRoot SP without a gutta-percha point. The root canals of group B were filled with iRoot SP using continuous wave of condensation technique. The root canals of group C were filled with AH Plus (root canal sealer) using continuous wave of condensation technique. Models were built to measure leakage with the quantitative method using glucose. The concentration of glucose leaked from the crown to the root was measured with a glucose oxidase-peroxidase method on the 1st day and in the 1st

2nd

3rd

4th

5th and 6th weeks during the experimental period. Voids in the root canal fillings were assessed using cross-section images from micro-CT scanning.       Results      During the 1st to 4th weeks

there was almost no glucose leakage in the 3 experimental groups

and the average daily leakage concentration was less than 0.18 mmol/L. In the 5th and 6th weeks

there was glucose leakage (0.18 mmol/L) in group C

and there were significant differences between group C and group A

as well as differences between group C and group B (P0.05). Micro-CT scanning found that voids were formed only at the apical part (1 mm) in group A

while voids are formed in the root canals in group B and group C.       Conclusion      iRoot SP as cement paste has excellent sealing ability in root canal three-dimensional obturation

and can realize primary monoblocks without damage to periodontal tissue.