Microleakage of composite restorations after acid or Er-YAG laser cavity treatments.
OBJECTIVE
The purpose of this study was to compare microleakage of Class V restorations following acid, laser or laser and acid treatment of cavity walls.


METHODS
Standardized lingual and buccal Class V preparations were made in 18 human extracted third molars. The preparations were randomly assigned to three equal groups (n=12). Group 1: cavities were treated with 35% phosphoric acid. Group 2: cavities were irradiated with an Er-YAG laser at 2Hz and 250mJ on dentin and 300mJ on enamel, with water cooling. Group 3: cavities were irradiated with the laser before acid etching. Scotchbond 1 Adhesive System and Z100 resin composite were used for restorations. The specimens were stored in water for 24h at 37 degrees C and thermally cycled (500x) between 6-60 degrees C. After 24h immersion in 0.5% basic fuchsin, dye penetration was recorded according to an ordinal scale. Data were analysed using non-parametric statistical tests (Kruskal-Wallis and Mann-Whitney).


RESULTS
On the occlusal walls, microleakage in acid etched cavities was significantly lower than that achieved after laser treatment (P<0.001) or after both treatments (P<0.05). On the gingival walls, no statistical differences were found.


CONCLUSIONS
Laser irradiation of enamel is not a valid alternative to acid-etching pretreatment for resin composite materials adhesion. Acid etching alone gave the lowest microleakage at the occlusal margin. No differences were found for microleakage on gingival wall, although lased dentin surfaces presented several characteristics that appear to be advantageous for bonding.
Ceballos
L
L
Department of Dental Materials, University of Granada, Granada, Spain.
Osorio
R
R
Toledano
M
M
Marshall
G W
GW
D000134:Acid Etching, Dental; D000538:Aluminum Silicates; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification / Q000379:methods*; D003743:Dental Enamel / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D003763:Dental Leakage / Q000145:classification*; D003793:Dental Restoration, Permanent / Q000145:classification; D003804:Dentin / Q000187:drug effects / Q000528:radiation effects / Q000648:ultrastructure; D004871:Erbium; D006801:Humans; D007834:Lasers; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000008:administration & dosage; D019279:Resin Cements / Q000737:chemistry; D012394:Rosaniline Dyes; D012822:Silicon Dioxide; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013816:Thermodynamics; D014867:Water; D015019:Yttrium; D015040:Zirconium
D000538:Aluminum Silicates; D003188:Composite Resins; D010756:Phosphoric Acids; D019279:Resin Cements; D012394:Rosaniline Dyes; C083568:Z100 composite resin; D014867:Water; D015019:Yttrium; C025485:basic fuchsin; D012822:Silicon Dioxide; D004871:Erbium; C041330:Scotchbond; D015040:Zirconium