IADR Abstract Archives
Effect of Diode Laser on Tensional Strength of Human Dentin
Objectives: To evaluate the effect of the 940 nm diode laser on the tensile strength of human radicular dentin
Methods: Experimental in vitro study. Protocol was approved by IRB. After a pilot study, sample size was calculated using a statistical formula. Ninety (90) human premolars extracted for orthodontic reasons were collected and stored in 0.9% saline solution for seven days. Then, they were randomly distributed into three groups of 30 teeth each: (1) control group (without mechanical preparation and irrigation); (2) experimental group 1, which was mechanical instrumented with a rotatory system files Wave One Gold Primary (Dentsply, Sirona) and irrigated with 5.25% sodium hypochlorite at 40°C; (3) experimental group 2, the same instrumentation and irrigation protocol was performed as Group 1, followed by 940 nm diode laser irradiation at 1.5W with a speed of 2mm/s. The teeth were sectioned to obtain an hourglass shaped specimen using a low speed cutter (Isomet 1000). They were observed using a stereomicroscope (STEMI 2000-C Zeiss®, Jena, Germany) in order to determinate the presence of cracks that could affect the mechanical properties evaluated. Tensile strength tests were perfomed (0,5mm/min crosshead speed) using the Universal Testing Machine (Instron® 2736-015, Instron corp, USA). Statistical analysis was performed using the Box Plot analysis and Tukey test
Results: Statistically significant differences (p=1,967x10-6) were observed when the three groups were compared, rejecting the null hypothesis. Control group (Mean 45.49 MPa) and experimental group 1 (Mean 62.95 MPa), reported statistically similar values. While the behavior of experimental group 2 showed the highest mean value of tensional strength (83.48 MPa) and reported statistically significant differences when it was compared with the other two groups
Conclusions: Instrumentation and irrigation protocol that includes the use 940 nm diode laser increased the tensile strength of human radicular dentin
Methods: Experimental in vitro study. Protocol was approved by IRB. After a pilot study, sample size was calculated using a statistical formula. Ninety (90) human premolars extracted for orthodontic reasons were collected and stored in 0.9% saline solution for seven days. Then, they were randomly distributed into three groups of 30 teeth each: (1) control group (without mechanical preparation and irrigation); (2) experimental group 1, which was mechanical instrumented with a rotatory system files Wave One Gold Primary (Dentsply, Sirona) and irrigated with 5.25% sodium hypochlorite at 40°C; (3) experimental group 2, the same instrumentation and irrigation protocol was performed as Group 1, followed by 940 nm diode laser irradiation at 1.5W with a speed of 2mm/s. The teeth were sectioned to obtain an hourglass shaped specimen using a low speed cutter (Isomet 1000). They were observed using a stereomicroscope (STEMI 2000-C Zeiss®, Jena, Germany) in order to determinate the presence of cracks that could affect the mechanical properties evaluated. Tensile strength tests were perfomed (0,5mm/min crosshead speed) using the Universal Testing Machine (Instron® 2736-015, Instron corp, USA). Statistical analysis was performed using the Box Plot analysis and Tukey test
Results: Statistically significant differences (p=1,967x10-6) were observed when the three groups were compared, rejecting the null hypothesis. Control group (Mean 45.49 MPa) and experimental group 1 (Mean 62.95 MPa), reported statistically similar values. While the behavior of experimental group 2 showed the highest mean value of tensional strength (83.48 MPa) and reported statistically significant differences when it was compared with the other two groups
Conclusions: Instrumentation and irrigation protocol that includes the use 940 nm diode laser increased the tensile strength of human radicular dentin
