Apical Diffusion of Three Kinds of Calcium Hydroxide in Vitro

Objective: To investigate the diffusion effect of calcium hydroxide in periapical simulation of the diffusion model. Methods:Pipetman pipette tips ,plastic syringes and BHI agar were prepared to be periapical simulation of the diffusion model. 120 simulation models was divided into three groups. Group 1: 100µl 20% calcium hydroxide suspension were sealed in pipette tips; group 2 : 100µl 90% calcium hydroxide cataplasm were sealed in; group 3: 100µl calcium hydroxide points and were sealed in. By different apical aperture (15#,25#,40#,80#), each group was divided into four subgroups(each subgroup 10). Preparation of 12 other simulation models sealed with distilled water as a control. pH values and Ca2 + concentration were measured by PH analyzer and calcium analyzer respeactively. The data was collected to establish a database , using with SPSS13.0 software packaage, randomized block design ANOV was performed. Results: The average pH value (8.26, S=0.86) of group 1 was signifacantly higher than that in group 2 (7.96, S=0.702) and Group 3 (7.83, S=0.59) (p <0.05), but no significant difference between the group 2 and group 3.The average calcium concentration of group 1 (29.87ppm. S=10.76) was signifacantly higher than that in group 2 (24.62ppm. S=10.40) and group 3(16.42ppm, S=5.70). There were significant differences among the three groups (p <0.05). The results also showed that the average pH value and the average calcium concentration were increased with apical aperture.There were significant differences between each group (p <0.05). Conclusion: The diffusion effect of calcium hydroxide suspension in periapical simulation of the diffusion model was better than calcium hydroxide cataplasm and calcium hydroxide points; the diffusion effect is also proportional with apical aperture.