A Confocal Laser Scanning Microscope investigation of different dental adhesives bonded to root canal dentine.
OBJECTIVE
To evaluate the resin-dentine interface of different adhesive systems and corresponding luting cements proposed for bonding fibre posts to root canal dentine.


METHODS
Fifty extracted maxillary canines and central incisors were used. After root canal treatment the teeth were randomly divided into five groups of 10 teeth each. Fibre posts were inserted with five different adhesive systems and corresponding luting cements. Group 1: Clearfil Core/New Bond (Kuraray), group 2: Multilink (Vivadent), group 3: Panavia 21/ED Primer (Kuraray), group 4: PermaFlo DC (Ultradent), and group 5: Variolink II/Excite DSC (Vivadent). The primer was labelled in each case with 0.1% Rhodamine B isothiocyanate (RITC). Each root was sectioned into 2 mm thick slices at 1, 4 and 7 mm below the cementoenamel junction. The resin-dentine interface was evaluated using a Confocal Laser Scanning Microscope; the thickness of the hybrid layer and the number of resin tags were measured. The statistical analysis was performed using nonparametrical tests for comparisons between groups; for overall comparisons the Kruskal-Wallis test was used. Intraindividual analysis within teeth was performed using a linear model.


RESULTS
The thickness (microm) of the hybrid layer of group 1 (5.45; SD 1.21), group 4 (3.36; SD 1.59), and group 5 (4.33; SD 1.19) was significantly higher than in the other groups (P < or = 0.05). The number of resin tags observed in group 1 was significantly higher than in groups 2-4 (P < 0.05), but did not differ from group 5. Each group showed significantly more resin tags in the coronal and in the central part of the root canal than in the apical part (P < 0.001).


CONCLUSIONS
Conditioning of the root canal dentine with phosphoric acid and the use of one- and two-bottle-bonding systems gave a thicker and more uniform hybrid layer with considerably more resin tags than observed after the use of 'self-etching' adhesives. This might provide a more durable bond of the post to root canal dentine.
Bitter
K
K
Department of Operative Dentistry and Periodontology, School of Dental Medicine, Campus Benjamin Franklin, Charité--Universitätsmedizin Berlin, Berlin, Germany. kerstin.bitter@charite.de
Paris
S
S
Martus
P
P
Schartner
R
R
Kielbassa
A M
AM
D000134:Acid Etching, Dental / Q000379:methods; D003188:Composite Resins / Q000737:chemistry; D003481:Cuspid; D001840:Dental Bonding; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005456:Fluorescent Dyes; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018613:Microscopy, Confocal; D010710:Phosphates / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry; D012235:Rhodamines; D013499:Surface Properties
C029849:Clearfil Bonding Agent; C469237:Clearfil Core; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C420130:Excite cement; D005456:Fluorescent Dyes; D008689:Methacrylates; C093719:Panavia TPN-S; C423507:PermaFlow; D010710:Phosphates; D010756:Phosphoric Acids; D019279:Resin Cements; D012235:Rhodamines; C103502:Variolink; C027755:rhodamine isothiocyanate