Fracture Forces of Dentin after Surface Treatment with High Speed Drill Compared to Er:YAG and Er,Cr:YSGG Laser Irradiation

Abstract

Dental tooth restorative procedures may weaken the structural integrity of the tooth, with the possibility of leading to fracture. In this study we present findings of coronal dentin strength after different techniques of surface modification. The fracture strength of dentin beams after superficial material removal with a fine diamond bur high speed drill hand piece, Er:YAG (2.94 μm, 8 J/cm2), and Er,Cr:YSGG (2.78 μm, 7.8 J/cm2) laser irradiation slightly above the ablation threshold was measured by a four-point bending apparatus. Untreated dentin beams served as a control. A total of 58 dentin beams were manufactured from sterilized human extracted molars using the coronal part of the available dentin. Mean values of fracture strength were calculated as 82.0 ± 27.3 MPa for the control group (n = 10), 104.5 ± 26.3 MPa for high speed drill treatment (n = 10), 96.1 ± 28.1 MPa for Er,Cr:YSGG laser irradiation (n = 20), and 89.1 ± 36.3 MPa for Er:YAG laser irradiation (n = 18). Independent Student's t-tests showed no significant difference between each two groups (p > 0.05). Within the parameter settings and the limits of the experimental setup used in this study, both lasers systems as well as the high speed drill do not significantly weaken coronal dentin after surface treatment.

Fracture resistance of root-filled teeth after cavity preparation with conventional burs, Er: YAG and Er,Cr: YSGG lasers

“…This was also confirmed by Corona et al (17) and Fornaini et al (18). Franzen et al (15) reported that minimal invasive cavities can be prepared and patient comfort can be enhanced by using Erbium lasers during cavity preparation. Accordingly, despite the present study found that fracture resistance did not vary either with burs or with laser, other advantages of cavity preparation with laser mentioned above may also motivate the clinicians to use Erbium lasers for cavity preparation.…”

“…The studies of Meister et al tine more than exogenous water, while Er,Cr:YSGG laser uses exogenous water more than endogenous water. Franzen et al (15) found that similar microstructural changes occur if adequate water supply is provided for both type of lasers. We assume that the similarity in the fracture strength values of laser groups is related to providing sufficient amount of water in the present study.…”