Energy output reduction and surface alteration of quartz and sapphire tips following Er:YAG laser contact irradiation for tooth enamel ablation

Abstract

In contact enamel ablation, the sapphire tip appeared to be more resistant than the quartz tip. The quartz tips showed similar patterns of energy reduction and surface alteration, whereas the sapphire tips revealed a wider and more characteristic variation among tips. Lasers Surg. Med. 41:595-604, 2009. (c) 2009 Wiley-Liss, Inc.

Energy output reduction and surface alteration of quartz tips following Er:YAG laser contact irradiation on soft and hard tissues <i>in vitro </i>

“…Thus, the distinct tip-wear observed in hard tissue groups would be primarily due to high mechanical stress during ablation. However, compared to the severe concavity observed in the case of enamel ablation 40) , the degree of surface abrasion in the calculus and bone groups was much smaller in the present study. These differences could be attributed to the difference in the hardness of the target tissues as well as the level of energy output employed.…”

“…The rate of energy reduction after 60-min irradiation was minimal for soft tissue ablation, and the soft tissue W(−) group maintained the highest energy output ratio (94.3%), followed by the soft tissue W(+) (91.4%) and bone W(+) (87.0%) groups. The lowest energy output ratio was observed in the calculus W(+) group (79.0%); however, these values were much higher than the remarkable reduction shown for enamel ablation (45.3%), which was previously reported by Eguro et al 40) . Unlike the hard tissue groups such as calculus and bone ablation, the contact surface of quartz tips in the soft tissue groups maintained a smooth appearance without incurring severe surface degradation even after 60-min irradiation.…”

“…However, information concerning the alteration of contact tips and changes in energy output after periodontal applications is insufficient [37][38][39][40][41] . Therefore, in the present study, changes in the energy output and surface topography of the quartz tips following ErL contact irradiation on periodontal soft and hard tissues were investigated.…”

“…Generally, the destruction of the contact surface could be caused by physical stresses such as severe impact from extensive pressure and shock waves as well as by the thermal stress of the momentary temperature increase of the contact surface, which is inevitable during contact irradiation even though water spray is used 40) . However, considering the present results showing only very slight temperature increases of the lateral surface of the tips, water spray may have effectively minimized the temperature elevation of the tips, thereby minimizing the thermal damage of the contact surface.…”

“…Previous studies demonstrated that the energy output reduction from contact tips was related with both the damage to the tip and the presence of contaminants on the contact surface 39) . Generally, two types of contact tips, quartz or sapphire crystal rods, are utilized for ErL, and the quartz tip appears to be less resistant than the sapphire tip 40) . In periodontal usage, ErL is irradiated on various tissues such as the root surface with subgingival calculus, gingiva, and bone tissue, and the curved type tips made of quartz crystal are clinically useful for various applications including insertion into periodontal pockets.…”