Evaluation of cutting efficiency and thermal damage during soft tissue surgery with 940 nm‐diode laser: An ex vivo study

Abstract

Objectives: To investigate quantitatively the cutting efficiency and the thermal effects in the surrounding soft tissues of incisions that are induced by a 940 nmdiode laser with different power settings. Materials and Methods: Fifty-four gingival samples were prepared from the lower jaws of freshly slaughtered German-land race pigs and were randomly divided into 9 groups (n = 6) according to the adjusted output power (1, 1.5, 2, 2.5, 3, 3.5, 4, 5 and 6 W). Five incisions were implemented for each sample using a diode laser (940 nm) in continuous wave with an initiated tip resulting in 30 incisions for each experimental group utilizing a three-dimensional computer-controlled micropositioner. The samples were prepared for histometric evaluation using a transmitted light microscope. The cutting depth and width and the thermal damage were recorded for each sample and the efficiency factor γ was calculated. Results: The highest cutting efficiency (γ z = 0.81 ± 0.03) exhibited the group with 5 W output power (p < 0.05), while the lowest (γ z = 0.45 ± 0.11) showed the 1-W group (p < 0.05). Over 3.5 W there was a rapid increase in the size of thermal damage of the incisions, especially for 6 W, which presented the largest. Conclusions: The most effective power parameters of diode laser (940 nm) for soft tissue surgery were from 3 to 5 W. The outcomes of the current study may help to establish clinical protocols for the use of diode lasers (940 nm) in soft tissue surgery in contact mode assisting dental professionals to achieve optimal clinical results and avoid complications. K E Y W O R D S cutting depth, diode laser, efficiency factor, gingival tissues, output power, thermal damage

Temperature changes in the pulp chamber and bleaching gel during tooth bleaching assisted by diode laser (445 nm) using different power settings

“…The parameters of a laser beam that determine its interaction with matter are the wavelength emitted by the laser device, the average power, and other temporal characteristics of the radiation, such as continuous versus pulsed delivery, pulse repetition, pulse duration, and time of irradiation [ 32 ]. In the present investigation, the only variable was the average power, which ranged from 0.5 to 2 W. Output power of laser radiation expresses the amount of energy induced per unit time at the tip of the handpiece of the laser device [ 33 ]. Besides, the average power of a laser beam is the average amount of work done or energy converted per unit of time [ 34 ].…”