Thermal Effect of Er:YAG Laser Pulse Durations on Teeth During Ceramic Bracket Debonding

Abstract

Debonding of the ceramic brackets with the aid of laser technology has become a certified technique in the field of orthodontics, as the use of a laser eliminates the problems of debonding that are associated with the traditional method. These problems may include enamel cracking and broken ceramic brackets, as well as the pain experienced by the patient during the removal of ceramic brackets [1]. Moreover, the use of a laser reduced the efforts and time needed for brackets debonding through thermal annealing of orthodontic brackets [2]. However, the effects of different lasers on the teeth and pulp tissue have not been fully determined. AbstractBackground. Deboning of ceramic brackets using a Er:YAG laser has become an acceptable method to facilitate the removal of such type of brackets. Therefore, research has been conducted to establish safer and more effective techniques. The pulse duration is one of the most critical parameters with respect to thermal effect on the pulp vitality. Objectives. The goal of the current research is to evaluate the thermal effect of different Er:YAG laser pulse durations in order to establish safe and effective protocols of debonding ceramic brackets. Material and Methods. The sample consisted of 45 premolars extracted for orthodontic purposes. A ceramic bracket was bonded to each tooth. The sample was divided into three groups: 15 teeth for pulse duration of 50 µs, 15 teeth for pulse duration of 100 µs, and 15 teeth for pulse duration of 300 µs. All the ceramic brackets were exposed to the Er:YAG laser for 6 s by laser scanning method, with the same air and water conditions, as well as the same pulse energy and repetition rate. The tooth temperature was monitored during debonding the brackets by a thermal camera, and the ceramic bracket was debonded after 18 s. Then, the samples were examined under a microscope to evaluate the presence of the adhesive material. Results. The results showed the absence of a statistically significant difference between the pulse duration of 50, 100 and 300 µs in relation to the rise in temperature of the tooth. However, a statistically significant difference was found in relation to the presence of adhesive materials between pulse duration 50 µs and both 100 and 300 µs, with no statistically significant difference between 100 and 300 µs. Conclusions. Within the limits of this study, both Er: YAG pulse durations of 100 and 300 µs are preferred during ceramic brackets debonding using the laser scanning method (Dent. Med. Probl. 2016, 53, 3, 352-357).

Erbium laser‐assisted ceramic debonding: a scoping review

“…Laser transmission energy was also used in relation to the laser application 39,54 . Shear bond strength (SBS), adhesive remnant index (ARI), and mode of failure were also examined in several studies 9,10,12,26,28–35,40,41,52,53 . One study examined the laser pulse values 13 and another examined the remaining cement volume 51 .…”

Orthodontic Bracket Removal Using LASER-Technology—A Short Systematic Literature Review of the Past 30 Years

“…Laser technology using Er:YAG lasers presents some advantages when used for debracketing due to their versatility. A proper adjustment of their settings such as water/air concentration, power, used energy, frequency, time, and irradiation method is essential in protecting the integrity of the enamel surface and preventing the increase of temperature in the intrapulpal chamber beyond the acceptable thresholds [30,31,40].…”

“…Even if Tocchio [38] proved in 1993 that the use of an KrF-excimer laser source of 248 nm creates a photoablative debracketing process using only one pulse, other studies [29] show that Er:YAG lasers of 2.94 µm is a better choice for clinical use. While the use of an 248-nm excimer laser for medical purposes is prohibited as its emission in the UV band is the same with DNA absorption, the Er:YAG laser is well-appreciated for its versatility, an increased absorption in water of more than 10,000/cm allowing the debracketing to take place by a similar blowoff process without the risk of removing a great amount of adhesive resin from below the bracket and ensuring that thus preventing damage to the enamel [31].…”

Comparative Study of Transmission of 2940 nm Wavelength in Six Different Aesthetic Orthodontic Brackets

“…The debracketing of ceramic brackets using erbium lasers has become an approved technique in the scope of orthodontics as the problems associated with the debonding of ceramic brackets using conventional methods are avoided when this laser is used [ 36 ]. These problems may include pain experienced by the patient during the removal of the ceramic bracket and enamel cracking and fracturing [ 33 , 37 ].…”

“…Debonding with Er: YAG lasers (2940 nm) is still controversial among researchers because, according to some of them, the thermomechanical ablation that occurs in the superficial layer of the adhesive resin after the irradiation of the ceramic bracket with an erbium laser could lead to bond weakening [ 39 ]. Per contra, some researchers have found that the dominant effect is thermal softening, which weakens the adhesion strength between the resin and the ceramic bracket base [ 36 , 40 ].…”