Scanning electron microscope analysis of the root dentin bonding interface filled with different pastes or bonded by different program in fiber post and resin bonded repair / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To observe the influence of different bonding process and three different root canal sealing materials on microstructure of root canal dentin bonding interface after fiber post and resin bonding, so as to improve clinical operation steps and to optimize fiber post resin bonding effect.</p><p><b>METHODS</b>Fifteen human single mandibular first premolars were selected. Three were bonded with fiber posts through Relyx Unicem conventional bonding steps after filled with root canal sealing materials of zinc oxide eugenol paste (Group A), and another three were bonded through the same steps after filled with sealing materials of Vitapex (Group B). The other nine were filled with sealing materials of AH Plus, randomly divided into three groups and bonded through different steps as follows: conventional bonding steps only (Group C), etching with 35% phosphoric acid before conventional bonding steps (Group D), and etching and coating with Singlebond 2 adhesive before conventional bonding steps (Group E). After immersed in saline solution for one week, all the roots were cut into three sections of 3 mm in thickness with emery chip and numbered as crown section, middle section and tip section respectively. The samples were observed the resin protrusion in mixed layer of dentin interface and dentinal tubules by scanning electron microscopy.</p><p><b>RESULTS</b>We observed the resin protrusion in microstructures of the roots bonded through Relyx Unicem after filled with three different root canal sealing materials (Group A, B, C, E): most obvious in the root crown sections, middle in the root middle sections and least in the root tip sections. Differences were observed in roots filled with different sealing materials: little resin protrusion were observed in crown sections only in Group A and B, but large number of resin protrusion were found in crown and middle sections in Group C-E. Compared with Group C, no more resin protrusion were found in Group D. More and elongated resin protrusions were found in Group E.</p><p><b>CONCLUSIONS</b>We recommend using AH Plus as root canal sealing materials for residual crown and root needed to strengthen by fiber post. It is no need to etch before Relyx Unicem conventional bonding steps. However, coating Singlebond 2 adhesive after acid etching has the potential to increase fiber post cementation.</p>

Endotoxin deactivation in artificial glass root canals with ultrasonic treatment / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the deactivation of the endotoxin in artificial glass root canals with ultrasonic vibration.</p><p><b>METHODS</b>80 artificial glass root canals were randomly divided into 8 groups: Ultrasonic vibration of 5 minutes, 7 minutes, 10 minutes, ultrasonic vibration of 5 minutes together with 3% H2O2 solution, only 3% H2O2 solution, ultrasonic vibration of 5 minutes together with 5.25% NaClO solution, only 5.25% NaClO solution and the control. Standard endotoxin solution was introduced into each root canal. Different time's ultrasonic vibration was applied to different groups. After ultrasonic vibration, the endotoxin activity of each group was tested by kinetic turbidimetric limulus test.</p><p><b>RESULT</b>There were no significant differences among the groups of different time ultrasonic vibration and the control (P>0.05). There was great statistical difference between each group with root canal rinse solution and the control (P<0.001). The endotoxin activity of the test was significantly lower than the control. There was no significant difference between the groups of only rinse solution and rinse solution together with ultrasonic vibration.</p><p><b>CONCLUSION</b>Under the condition of this study, the only ultrasonic vibration can not deactivate the endotoxin of infected root canals and can not intensify the effect of root canal rinse solution.</p>