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A root canal treatment is used in cases of dental preservation. A successful root canal treatment requires a tight seal of the canal. This is ensured by a firm bond between the dental structure and the sealer, so that a bacterial immigration is suppressed. Aim of the study is to investigate the bond strength between sealer and dentine under consideration of various temporary medical fillings. Therefore the adhesive force of the sealer Acroseal is examined.
2 Material and Method
60 extracted human teeth with straight roots that were not previously endodontically treated were selected for the study. Their dental crown was detached by a diamond cutting disc.
Root canals were prepared with BioRaCe instruments to a working length of 8 mm to ISO size 60. During the preparation the canals were rinsed with NaOCl (3%).
The 60 roots were subdivided into 6 categories. 40 of the roots were assigned to the 4 medicaments and 20 roots served as a reference. The reference groups were subdivided into wet and dry storage with 10 roots each. The 4 medicaments stayed within the dentine for 14 days. All 6 groups were subject to the same irrigation protocol before applying the sealer.
1.) NaOCl (3%) + 1 min activation through the endodontic activator, 2.) EDTA + 1 min activation through the endodontic activator, 3.) NaOCl (3%), 4.) Aqua dest..
After drying the canals with paper points, the steal spreaders were glued in with Acroseal. The last step was to strain the roots until the bonding failure between the dentine and sealer was determined.
Acroseal revealed the highest bond-strength values (1,58 MPa) under moist conditions within the root canal. Calcium hydroxide, either used as point (0,96 MPa) or paste (1,03 MPa), showed comparable bond-strength results with Acroseal. After root canals were dressed with Activ Points, the lowest bond strength in the whole study were obtained (0,38 MPa). The application of chlorhexidine digluconate gel showed a high bond strength values (1,32 MPa). Differences in terms of bond strength after the medical insertion were not significant between the groups (Kruskal-Wallis-Test; p=0,061).
Except for chlorhexidine digluconate gel, all medicaments reduce the bond-strength of Acroseal to the root canal dentine. When the root canal were moist during the root canal filling, the highest bond strength values were achieved. Therefore, moisture during placement of Acroseal results in an increase in terms of bond strength.