Effects of different application durations of ER:YAG laser on intrapulpal temperature change during debonding

Abstract

This study was done to determine the amount of lasing time required to remove ceramic brackets safely without causing intrapulpal damage by using Er:YAG laser with the scanning method. Part 1: 80 bovine mandibular incisors with ceramic brackets were randomly assigned into four groups of 20 as one control and three study groups. In the study groups, brackets were debonded after lasing for 3, 6, and 9 s, whereas debonding was performed without lasing in the control group. Shear bond strengths and ARI scores were also measured. Part 2: 30 human premolars with ceramic brackets were randomly divided into three groups of ten, as 3, 6, and 9 s of lasing durations. Intrapulpal temperature was measured at the same lasing times by a thermocouple. Statistically significant lower shear bond strengths were found in study groups compared to the control. A negative correlation was seen between the bond strengths and ARI scores in such a way that, as the shear bond strengths decreased, the ARI scores increased. Temperature increases for all the study groups were measured below the 5.5°C benchmark. All lasing times were effective for debonding without causing enamel tear outs or bracket failures. The temperature proportionally increased with the extension of the lasing duration. Six-second lasing by the scanning method using Er:YAG laser was found to be the most effective and safest way of removing the ceramic brackets without causing damage to the enamel and pulpal tissues.

Laser-Aided Ceramic Bracket Debonding: A Comprehensive Review

“…8,15,19 As shown by Nalbantgil et al, 15 the temperature proportionally increased as a function of laser irradiation time. They reported that lasing via a scanning approach was the most effective and safest way to debond ceramic brackets without causing injury to pulpal tissues.…”

“…In another study Dostalováa et al 17 used 1997 nm longitudinally diode pumped Tm:YAP laser for debonding monocrystalline and polycrystalline ceramic bracket and concluded that the temperature rise was safe in both bracket types. Nalbantgil et al 15,19 used Er:YAG laser for bracket removal and observed that temperature increases for all specimens were below the 5.5°C benchmark. Sarp et al 8 used 1070-nm ytterbium fiber laser and reported minimal intrapulpal temperature rise.…”

“…Oztoprak et al 14 found that the Er:YAG laser at 4.2 W for 9 seconds was effective in reducing shear bond strength of poly crystalline ceramic brackets. Nalbantgil et al 15 also showed that different lasing durations (3, 6 and 9 seconds) were efficient in debonding polycrystalline brackets. In comparing the shear bond strength of ceramic bracket after different time lags between lasing and debonding, Tozlu et al 16 concluded that the ideal parameter was 6 seconds of Er-YAG laser irradiation followed by 18 seconds of time lag for debonding.…”

“…Investigating the effect of a diode laser on shear bond strength of ceramic brackets, Feldon et al 13 and Almohaimeed et al 18 found that diode laser could significantly decrease shear bond strength of monocrystalline bracket and pre-coated ceramic brackets, respectively. Oztoprak et al, 14 Nalbantgil et al, 15 Nalbantgil et al 19 and Tozlu et al 16 investigated the effect of Er:YAG laser on debonding. Oztoprak et al 14 found that the Er:YAG laser at 4.2 W for 9 seconds was effective in reducing shear bond strength of poly crystalline ceramic brackets.…”

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

“…A newly developed, effective and safe method for debonding ceramic brackets is called the scanning method by the Er:YAG laser, which was described by Nalbantgil et al [10]. This method is performed by applying the Er:YAG laser beam on a ceramic bracket while moving the hand piece horizontally over the entire surface of the ceramic bracket with a specific scanning time, frequency and specific energy [2].…”