IADR Abstract Archives
Does Tooth Preparation with a CO2-Laser Prevent Demineralization Around Restorations?
Objectives: To determine if cavity preparation using a CO2 laser (Solea® Dental Laser, Convergent Dental) can prevent demineralization and microleakage around a restoration, compared to traditional carbide-bur preparation.
Methods: Forty human posterior teeth were randomized into 8 groups and initial Vickers surface hardness measurements (MicroMet® 2104 Buehler) of enamel were taken. Twenty samples were prepared 1.5-2mm deep and 4mmx4mm on the mesial side, with the gingival floor 1mm below the cementoenamel-junction, using the 9.3μm CO2 laser. The other twenty samples were identically prepared using a carbide bur. Each group (n=5) was restored with Filtek™ One Bulk Fill Restorative (3M)(Filtek OB), ACTIVA™ BioACTIVE-RESTORATIVE™ (Pulpdent)(ACTIVA), GC Fuji IX GP® FAST (GC)(Fuji), or Filtek™ Bulk Fill Flowable Restorative (3M)(Filtek F) per manufacturer instructions. Samples were placed in 0.05M acetate buffer demineralizing solution for 7 days, thermo-mechanically cycled for 10,000 cycles between 4-5°C and 55-60°C with a dwell time of 15s, immersed in 2% methylene blue solution and cut longitudinally. Three Vickers surface hardness measurements 10μm apart of enamel and dentin were taken 50μm away from the restoration margin. Gingival margin microleakage was measured using OmniMet™ analysis. Laser and bur samples restored with the same material were compared using the two-sample t-test. Significance level was set at 0.0042 using the Bonferroni correction for multiple comparisons.
Results: Laser and bur groups had similar baseline enamel microhardness for all materials (Table 1). The sub-surface enamel microhardness of lased samples in ACTIVA and Filtek F groups, and the dentin microhardness of the lased samples in Filtek OB, ACTIVA, Fuji, and Filtek F groups were statistically significantly greater than bur prepared samples (Table 2). Microleakage (Table 3) was not statistically significantly different between laser and bur groups.
Conclusions: Cavity preparation using a CO2 laser can prevent demineralization around a restoration, compared to traditional carbide-bur preparation.
Methods: Forty human posterior teeth were randomized into 8 groups and initial Vickers surface hardness measurements (MicroMet® 2104 Buehler) of enamel were taken. Twenty samples were prepared 1.5-2mm deep and 4mmx4mm on the mesial side, with the gingival floor 1mm below the cementoenamel-junction, using the 9.3μm CO2 laser. The other twenty samples were identically prepared using a carbide bur. Each group (n=5) was restored with Filtek™ One Bulk Fill Restorative (3M)(Filtek OB), ACTIVA™ BioACTIVE-RESTORATIVE™ (Pulpdent)(ACTIVA), GC Fuji IX GP® FAST (GC)(Fuji), or Filtek™ Bulk Fill Flowable Restorative (3M)(Filtek F) per manufacturer instructions. Samples were placed in 0.05M acetate buffer demineralizing solution for 7 days, thermo-mechanically cycled for 10,000 cycles between 4-5°C and 55-60°C with a dwell time of 15s, immersed in 2% methylene blue solution and cut longitudinally. Three Vickers surface hardness measurements 10μm apart of enamel and dentin were taken 50μm away from the restoration margin. Gingival margin microleakage was measured using OmniMet™ analysis. Laser and bur samples restored with the same material were compared using the two-sample t-test. Significance level was set at 0.0042 using the Bonferroni correction for multiple comparisons.
Results: Laser and bur groups had similar baseline enamel microhardness for all materials (Table 1). The sub-surface enamel microhardness of lased samples in ACTIVA and Filtek F groups, and the dentin microhardness of the lased samples in Filtek OB, ACTIVA, Fuji, and Filtek F groups were statistically significantly greater than bur prepared samples (Table 2). Microleakage (Table 3) was not statistically significantly different between laser and bur groups.
Conclusions: Cavity preparation using a CO2 laser can prevent demineralization around a restoration, compared to traditional carbide-bur preparation.
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