In vitro effect of Q-switched Nd:YAG laser exposure on morphology, hydroxyapatite composition and microhardness properties of human dentin

• Main Authors: Retna Apsari, Siswanto Siswanto, Anita Yuliati, Noriah Bidin
• Format: Article
• Language: English
• Published: Universitas Airlangga 2011-12-01
• Series: Dental Journal: Majalah Kedokteran Gigi
• Subjects: Plasma; laser ablation; crystal structure; microhardness; hydroxyapatite; Nd:YAG laser; ablasi laser; struktur kristal; kekerasan mikro; hidroksiapatit; laser Nd:YAG
• Online Access: http://e-journal.unair.ac.id/index.php/MKG/article/view/849

<p><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Background: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>A Q-switched Nd:YAG laser was employed as a source of ablation. The fundamental wavelength of the laser is </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>1064 nm, with pulse duration of 8 nanosecond operates with uniphase mode of TEM</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>00</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>. In the following experiments, dentin samples </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>(without caries and plaque) are exposed to pulse laser with Q-switching effect at various energy dose. </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Purpose: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>The aim of this study </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>was to investigate the effect of laser ablation on dentin samples using Q-switched Nd:YAG laser exposure. </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Methods: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>The laser was </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>operated in repetitive mode with frequency of 10 Hz. The energy dose of the laser was ranging from 13.9 J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>, 21.2 J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2 </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>and 41.7 </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>. The target material comprised of human dentin. The laser was exposed in one mode with Q-switched Nd:YAG laser. Energy </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>delivered to the target through free beam technique. The exposed human dentin was examined by using x-ray diffraction (XRD) and </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>fluoresence scanning electron microscopy for energy dispersive (FESEM-EDAX). Microhardness of human dentin were examined by </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>using microhardness vickers test (MVT). </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Results: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>The result obtained showed that the composition of hydroxyapatite of the dentin after </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>exposed by Q-switched Nd:YAG laser are 75.02% to 78.21%, with microhardness of 38.7 kgf/mm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2 </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>to 86.6 kgf/mm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>. This indicated that </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>exposed pulsed Nd:YAG laser on the human dentin attributed to the phototermal effect. The power density created by the Q-switched </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Nd:YAG laser enables the heat to produce optical breakdown (melting and hole) associated with plasma formation and shock wave </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>propagation, from energy dose of 21.2 J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>. From XRD analysis showed that the exposure of Nd:YAG laser did not involve in </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>changing the crystal structure of the dentin, but due to photoablation effect. </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Conclusion: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>In conclusion, the application of Q-switched </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Nd:YAG laser as contactless drills in dentistry should be regarded as an alternative to the classical mechanical technique to improve </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>the quality of the dentin treatment.</em></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></p><p><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Latar belakang: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Mode Q-Switch pada laser Nd:YAG dapat menghasilkan fenomena ablasi pada dentin. Laser Nd:YAG yang digunakan </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>mempunyai panjang gelombang 1064 nm, durasi pulsa 8 ns beroperasi dengan mode TEM</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>00</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>. Sampel dentin yang digunakan tanpa karies dan </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>plak, yang dipapari laser dengan mode Q-switch dalam berbagai variasi dosis energi. </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Tujuan: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Tujuan penelitian ini adalah mengamati efek </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>ablasi dentin secara in vitro akibat paparan laser Nd:YAG Q-switch dengan pengamatan morfologi permukaan, komposisi hidroksiapatit, </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>dan uji kekerasan mikro. </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Metode: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Laser Nd:YAG Q-switch dengan frekuensi 10 Hz dan variasi dosis energi 13,9 J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>, 21,2 J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2 </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>dan </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>41,7 J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2 </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>ditembakkan pada sampel dentin manusia dengan teknik penyinaran bebas tanpa dilewatkan serat optik. Dentin yang terbuka </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>diamati menggunakan x-ray diffraction (XRD) dan fluoresence scanning electron microscopy for energy dispersive (FESEM-EDAX). </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Kekerasan mikro dari dentin juga diamati menggunakan microhardness vickers test (MVT). </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Hasil: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Hasil penelitian menunjukkan bahwa </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>komposisi hidroksiapatit dari dentin setelah paparan laser Nd:YAG Q-Switch menunjukkan peningkatan berkisar 75,02% sampai 78,21% </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>dibandingkan normal, dengan kekerasan mikro berkisar 38,7 kgf/mm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2 </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>sampai 86,6 kgf/mm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>. Perubahan pada struktur mikro tersebut </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>disebakan karena adanya efek fototermal. Kerapatan daya yang bervariasi berdasarkan variasi dosis energi menyebabkan efek panas </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>pada dentin yang menyebabkan adanya fenomena optical breakdown, yang ditandai dengan munculnya efek leleh dan lubang pada</em></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span> <span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>sampel karena produksi plasma dan adanya gelombang kejut, mulai dosis 21,2 J/cm</em><span style="font-family: Tribune-Italic; font-size: 7pt; color: #231f20; font-style: normal; font-variant: normal;"><em>2</em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>. Berdasarkan uji XRD, efek yang muncul pada </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>dentin tidak menyebabkan terjadinya perubahan struktur kristal hidroksiapatit, tetapi menyebabkan perubahan komposisi hidroksiapatit </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>yang disebut dengan fotoablasi. </em><span style="font-family: Tribune-Bold; font-size: 10pt; color: #231f20; font-style: normal; font-variant: normal;"><strong>Kesimpulan: </strong><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>Dapat disimpulkan bahwa penggunaan mode Q-switched pada laser Nd:YAG sebagai </em><span style="font-family: Tribune-Italic; font-size: 9pt; color: #231f20; font-style: normal; font-variant: normal;"><em>alat dengan kontak minimal dapat dijadikan teknik alternatif untuk meningkatkan kualitas perawatan dental.</em></span></span></span></span></span></span></span></span><br /></em></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></p>