| Popis: |
Objective To explore the effects of Er: YAG lasers with different pulse energies and of Er: YAG lasers combined with Duraphat on dentine surface morphology and the dentinal tubule exposure rate, thereby providing a theo⁃ retical basis and parameters for clinically treating dentine hypersensitivity with Er: YAG lasers. Methods Dentinal tu⁃ bule exposure models were divided into five groups, namely, group A (single Er: YAG laser exposure), group B (Du⁃ raphat+ Er: YAG laser), and group C (Er: YAG laser+Duraphat), which were exposed to 6 levels of pulse energy (80 mJ/ P⁃ 250 mJ/P), and experimental control group D (Duraphat group) and blank control group E. Scanning electron micros⁃ copy was used to observe dentine surface morphology and dentinal tubule closure in these groups, and Image⁃Pro Plus 6.0 software was used for image analysis to measure the exposure rates of the five groups of dentinal tubules. Results The dentinal tubule exposure rates for the A⁃D groups were significantly lower than that of the E group (P < 0.001); when the Er: YAG laser pulse energy was less than 250 mJ/P, the dentinal tubule exposure rates for the A⁃C groups were all lower than that of the D group, but when the pulse energy was higher than 250 mJ/P, the dentinal tubule expo⁃ sure rates for the A⁃C groups were higher than that of the D group, showing significant differences (P < 0.001); under the same handling method, when the pulse energy was 80～200 mJ/P, the dentinal tubule exposure rate decreased as the pulse energy increased. If the pulse energy reached 250 mJ/P, the exposure rate of the dentinal tubules increased in⁃ stead. There were apparently no significant differences between 80 mJ/P, 100 mJ/P, 160 mJ/P and 200 mJ/P in the A and C groups or between 80 mJ/P and 100 mJ/P in the B group (P > 0.05), while significant differences existed among the other groups (P < 0.05). Under the same pulse energy, the dentinal tubule exposure rates were A group > C group >B group; under different pulse energies, there existed significant differences between the A and B groups (P < 0.05); when the pulse energy was 120～250 mJ/P, there were significant differences between the B and C groups (P < 0.05), while there were no significant differences among other groups (P > 0.05). Conclusion Er: YAG lasers can close the dentinal tubules and play a cooperative role if combined with Duraphat; the effects of laser exposure are better if fluorine is ap⁃ plied beforehand; and dentinal tubule closure is positively correlated with the pulse energy of Er: YAG lasers within a certain energy scope, but when the pulse energy reaches 200 mJ/P, the dentine surface is excessively fused and injured. |
