CAJ | 학술논문

目的探索不同能量密度和扫描速度的飞秒激光切削牙釉质和牙本质的效率,以期为飞秒激光的临床应用提供参考.方法将离体牙(中切牙和第一磨牙各2颗)沿轴面纵切制成厚1 mm的牙釉质和牙本质试件各2个,选取36个牙釉质区域和48个牙本质区域作为实验区域.使用波长800 nm、脉宽30 fs、重复频率1000 Hz的飞秒激光器,聚焦直径25 μm,激光扫描速度设置为10和20 mm/s.通过调节激光功率将能量密度设置为1.33、1.77、2.21、4.42、8.85、17.69 J/cm2切削牙釉质,以及设置为0.44、0.66、0.88、1.33、1.77、2.21、4.42、6.63 J/cm2切削牙本质.用激光三维形貌测量显微镜测量切削体积,计算牙釉质、牙本质的切削效率.结果能量密度为8.85 J/cm2、扫描速度为20 mm/s时,飞秒激光牙釉质切削效率最大,为18.703×10-3 mm3/J;能量密度为2.21 J/cm2、扫描速度为20 mm/s时牙本质切削效率最大,为223.458×10-3 mm3/J.结论飞秒激光的能量密度和扫描速度对切削效率有明显的影响,选择适宜的能量密度和扫描速度可提高飞秒激光的牙本质和牙釉质切削效率.
목적 탐색불동능량밀도화소묘속도적비초격광절삭아유질화아본질적효솔,이기위비초격광적림상응용제공삼고.방법 장리체아(중절아화제일마아각2과)연축면종절제성후1 mm적아유질화아본질시건각2개,선취36개아유질구역화48개아본질구역작위실험구역.사용파장800 nm、맥관30 fs、중복빈솔1000 Hz적비초격광기,취초직경25 μm,격광소묘속도설치위10화20 mm/s.통과조절격광공솔장능량밀도설치위1.33、1.77、2.21、4.42、8.85、17.69 J/cm2절삭아유질,이급설치위0.44、0.66、0.88、1.33、1.77、2.21、4.42、6.63 J/cm2절삭아본질.용격광삼유형모측량현미경측량절삭체적,계산아유질、아본질적절삭효솔.결과 능량밀도위8.85 J/cm2、소묘속도위20 mm/s시,비초격광아유질절삭효솔최대,위18.703×10-3 mm3/J;능량밀도위2.21 J/cm2、소묘속도위20 mm/s시아본질절삭효솔최대,위223.458×10-3 mm3/J.결론 비초격광적능량밀도화소묘속도대절삭효솔유명현적영향,선택괄의적능량밀도화소묘속도가제고비초격광적아본질화아유질절삭효솔.
Objective To measure the effect of laser fluence and scanning velocity on ablation efficiency of enamel and dentin.Methods Two extracted human incisors and two molars were cut transversely along the axial plane with a diamond saw to obtain dentin and enamel slices with thickness of about 1 mm.Samples were fixed on a motorized translation stage,the linear reciprocating movement in the plane perpendicular to the direction of laser incident was programmed by the controller,and the laser focused on the tooth surface,then 36 ablation lines on enamel and 48 ablation lines on dentin were produced.A femtosecond laser system with wavelength of 800 nm,pulse width 30 fs,repetition frequency 1000 Hz was used,and the diameter of the focused spot was approximately 25 μm.A group of different fluence (1.33,1.77,2.21,4.42,8.85,17.69 J/cm2 for enamel and 0.44,0.66,0.88,1.33,1.77,2.21,4.42,6.63 J/cm2 for dentin) and two scanning velocity (10 mm/s and 20 mm/s) were tested.Confocal laser scanning microscope was used to measure the ablation volume.Ablation efficiency for enamel and dentin was then calculated.Results Under the fluence of 8.85 J/cm2 there was the highest ablation efficiency for enamel,18.703 × 10-3 mm3/J (20 mm/s),and the highest ablation efficiency for dentin was found under the fluence of 2.21 J/cm2,ie.223.458 × 10-3 mm3/J (20 mm/s).Conclusions Fluence and scanning speed of this femtosecond laser can affect ablation efficiency for both enamel and dentin,and this suggests that with appropriate choice of fluence and scanning speed we can improve the ablation efficiency for enamel and dentin.