title: [Study of apical diffusion of three different kinds of calcium hydroxide preparations in vitro].
abstract: 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 were divided into three groups. Group 1: 100 microl 20% calcium hydroxide suspension were sealed in pipette tips; group 2: 100 microl 90% calcium hydroxide cataplasm were sealed in; group 3: 100 microl calcium hydroxide points were sealed in. By different apical aperture (15#,25#,40#,80#), each group was divided into four subgroups (each subgroup contained 10). Preparation of 12 other simulation models sealed with distilled water were as a control. pH values and Ca(2+) concentration were measured by PH analyzer and calcium analyzer respectively. The data was collected to establish a database, using SPSS13.0 software package, randomized block design ANOVA was performed.
  
  
  RESULTS
  The average pH value (8.26, S=0.86) of group 1 was significantly 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 was found between group 2 and group 3. The average calcium concentration of group 1 (29.87 ppm. S=10.76) was significantly higher than that in group 2 (24.62 ppm. S=10.40) and group 3(16.42 ppm, 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).
  
  
  CONCLUSIONS
  The diffusion effect of calcium hydroxide suspension in periapical simulation of the diffusion model is better than calcium hydroxide cataplasm and calcium hydroxide points; the diffusion effect is also proportional to the apical aperture. Supported by Key Research Project of Science and Technology Bureau of Sichuan Province (Grant No.05SG022-007).
authors.affiliation: Department of Endodontics, West China College of Stomatology, Sichuan University, Chengdu 610041, Sichuan Province, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Gan
authors.forename: Shi-hai
authors.initials: SH
authors.lastname: Yin
authors.forename: Ling
authors.initials: L
authors.lastname: Zou
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Xie
authors.forename: Su-lan
authors.initials: SL
authors.lastname: Zhong
mesh_terms: D002126:Calcium Hydroxide; D004058:Diffusion; D066298:In Vitro Techniques
chemical_list: D002126:Calcium Hydroxide