Effect of Different Irradiation Times on the Occlusion of Dentinal Tubules When Using a Nd -YAG Laser - An <i>in Vitro</i> SEM Study
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2015-01-01 |
| Journal | Open Journal of Stomatology |
| Authors | Xiaoyu Guo, Jinhua Yu, Roger J. Smales, Chen Huifen, Hai-Yan Si |
| Institutions | Nanjing Medical University, The University of Adelaide |
| Citations | 2 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: High-Precision Laser-Material Interaction
Section titled âTechnical Documentation & Analysis: High-Precision Laser-Material InteractionâExecutive Summary
Section titled âExecutive SummaryâThis documentation analyzes the research on Nd:YAG laser irradiation effects on dentinal tubule occlusion, highlighting the need for high-stability laser systems and precision material analysis, areas where 6CCVDâs MPCVD diamond excels.
- Core Objective: Evaluate the quantitative effect of varying Nd:YAG laser irradiation times (0 s to 60 s) on sealing dentinal tubules to treat dentin hypersensitivity.
- Methodology: In vitro study using 2 mm thick human dentin disks, pre-treated with 27% EDTA to simulate exposed, patent tubules.
- Fixed Laser Parameters: The study maintained a fixed energy per pulse (120 mJ) and frequency (5 Hz), requiring highly stable laser optics and thermal management.
- Key Achievement: Optimum sealing was achieved at 60 s irradiation time, corresponding to a total energy density of 600 J/cm2.
- Quantitative Results: The dentinal tubule occlusion rate increased exponentially to 90.23% (± 2.24%) at 60 s.
- Dimensional Change: Tubule diameters decreased significantly and linearly, from an initial 4.18 ”m (control) to a minimum of 0.12 ”m (± 0.02 ”m) at 60 s.
- Relevance to 6CCVD: The studyâs reliance on high-fluence laser delivery and ultra-high-resolution SEM imaging (up to 3000x) underscores the need for high-performance diamond optics and stable microscopy substrates.
Technical Specifications
Section titled âTechnical SpecificationsâThe following data points were extracted from the study detailing the experimental setup and results:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Specimen Thickness | 2 | mm | Coronal dentin disks |
| Dentin Region Size | 2 x 3 | mm | Area irradiated per group |
| EDTA Concentration | 27 | % | Used for smear layer removal |
| Nd:YAG Wavelength | 1064 | nm | Standard Nd:YAG output (Implied) |
| Laser Energy per Pulse | 120 | mJ | Fixed parameter |
| Laser Frequency | 5 | Hz | Fixed parameter |
| Maximum Irradiation Time | 60 | s | Optimal treatment time (Group D) |
| Maximum Energy Density | 600 | J/cm2 | Achieved at 60 s irradiation |
| SEM Magnification (Diameter) | 3000 | x | Used for high-precision tubule measurement |
| Initial Tubule Diameter (0 s) | 4.18 (± 0.32) | ”m | Control group after EDTA treatment |
| Optimal Tubule Diameter (60 s) | 0.12 (± 0.02) | ”m | Minimum diameter achieved |
| Optimal Occlusion Rate (60 s) | 90.23 (± 2.24) | % | Maximum sealing efficiency |
| Statistical Significance (p) | < 0.001 | N/A | Significant difference among all groups |
Key Methodologies
Section titled âKey MethodologiesâThe experiment utilized precise material preparation and controlled laser parameters to achieve repeatable surface modification, followed by high-resolution analysis.
- Specimen Preparation: Four 2 mm thick coronal dentin disks were cut from human molars using a low-speed diamond saw.
- Smear Layer Removal: Disks were immersed in 27% ethylene diamine tetraacetic acid (EDTA, pH 7.4) for 2 minutes, followed by rinsing and 2 minutes of ultrasonic irrigation to expose patent dentinal tubule orifices.
- Region Randomization: Each disk was divided into four 2 mm x 3 mm regions, randomly assigned to one of four irradiation time groups (0 s, 20 s, 40 s, 60 s).
- Laser Irradiation: A Nd:YAG laser was positioned 1 mm above and perpendicular to the dentinal surface.
- Fixed Parameters: 120 mJ energy per pulse and 5 Hz frequency.
- Variable Energy Density: Ranging from 0 J/cm2 (0 s) to 600 J/cm2 (60 s).
- Post-Irradiation Treatment: Specimens were brushed for 3 minutes and stored in a constant temperature box at 37 °C.
- SEM Analysis: Specimens were dehydrated, sputter-coated in gold, and examined using a Scanning Electron Microscope (Model LEO-1530).
- Data Measurement: Dentinal tubule occlusion rates were calculated at 1500x magnification, and tubule diameters were measured at 3000x magnification.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful replication and advancement of high-fluence laser-material interaction studies, such as the one analyzed, require materials with extreme thermal stability, optical purity, and surface precision. 6CCVD specializes in providing the MPCVD diamond solutions necessary for these demanding engineering and scientific applications.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend research involving high-power Nd:YAG lasers and precision surface analysis, 6CCVD recommends the following materials:
- Optical Grade Single Crystal Diamond (SCD):
- Application: Essential for high-power laser optics (windows, output couplers, beam splitters) operating at 1064 nm.
- Benefit: SCD offers the highest known thermal conductivity (k > 2000 W/mK), ensuring minimal thermal lensing and maintaining the fixed 120 mJ/5 Hz parameters required for repeatable energy delivery, even at high energy densities (up to 600 J/cm2).
- Ultra-Flat SCD Substrates:
- Application: Ideal for mounting samples for high-resolution microscopy (SEM, AFM) and spectroscopy.
- Benefit: Our SCD is polished to an ultra-low roughness (Ra < 1 nm), providing an inert, stable, and extremely flat platform, critical for minimizing drift and maximizing image quality during 3000x SEM analysis of laser-modified surfaces.
- Polycrystalline Diamond (PCD) Heat Spreaders:
- Application: Thermal management for the laser diode pump source and associated electronics in the Nd:YAG system.
- Benefit: PCD plates (up to 125 mm) ensure efficient heat dissipation, stabilizing the laser systemâs output power and frequency, which is paramount for maintaining the precise dose-response relationship demonstrated in the study.
Customization Potential
Section titled âCustomization Potentialâ6CCVDâs in-house capabilities directly address the need for customized components in advanced research environments:
| Requirement from Research | 6CCVD Customization Capability | Specification |
|---|---|---|
| Precision Sample Handling | Custom Diamond Substrates/Plates | Plates/wafers up to 125 mm (PCD) |
| High-Fluence Optics | Custom Thickness Control (SCD/PCD) | Thicknesses from 0.1 ”m up to 500 ”m |
| Ultra-High Resolution Imaging | Advanced Polishing | Ra < 1 nm (SCD), Ra < 5 nm (PCD) |
| Integrated Sensors/Contacts | Custom Metalization Services | Deposition of Au, Pt, Pd, Ti, W, Cu |
| Unique Component Shapes | Precision Laser Cutting & Shaping | Custom dimensions and geometries |
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in optimizing MPCVD diamond properties for extreme environments. We can assist researchers in selecting the optimal diamond grade, orientation, and surface finish for similar High-Power Laser-Material Interaction projects, ensuring reliable performance and maximizing experimental throughput.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Objective: To evaluate the effect of different irradiation times on the occlusion of dentinal tubules when using Nd:YAG laser. Background data: Dentin hypersensitivity is a frequent problem that has limited treatment success despite many chemical and physical therapies. Methods: Four coronal dentin disks 2 mm thick were cut with a low-speed diamond saw from four freshly extracted intact first molars. The coronal dentin surface of each disk was divided into four regions, each approximately 2 mm Ă 3 mm. The dentin surfaces were treated with 27% EDTA then the four regions irradiated separately in a randomized pattern with a Nd:YAG laser (120 mJ, 5 Hz), using irradiation times of 0 s, 20 s, 40 s and 60 s, representing laser energies of 0 J/cm2, 200 J/cm2, 400 J/cm2 and 600 J/cm2, respectively. SEM photomicro-graphs were taken at 1500Ă and 3000Ă to calculate the dentinal tubule orifice occlusion rates and to measure the tubule diameters, respectively. Results: For the laser irradiation times of 0 s, 20 s, 40 s and 60 s, the corresponding dentinal tubule occlusion rates were 2.05 (SD 0.29)%, 10.01 (1.71)%, 23.58 (2.51)% and 90.23 (2.24)%, respectively; and the tubule diameters were 4.18 (0.32) ÎŒm, 3.46 (0.24) ÎŒm, 1.69 (0.32) ÎŒm and 0.12 (0.02) ÎŒm, respectively. There were significant differences among all groups for both measured variables (p †0.005). Conclusions: Within the limitations of this in Vitro study, when using a Nd:YAG laser at 120 mJ and 5 Hz, an irradiation time of 60 s achieved the best sealing of the coronal dentinal tubule orifices.