Thermal effects of λ = 808 nm GaAlAs diode laser irradiation on different titanium surfaces

Abstract

Diode lasers are widely used in dental laser treatment, but little is known about their thermal effects on different titanium implant surfaces. This is a key issue because already a 10 °C increase over the normal body temperature can induce bone injury and compromise osseo-integration. The present study aimed at evaluating the temperature changes and surface alterations experienced by different titanium surfaces upon irradiation with a λ = 808 nm diode laser with different settings and modalities. Titanium discs with surfaces mimicking different dental implant surfaces including TiUnite and anodized, machined surfaces were laser-irradiated in contact and non-contact mode, and with and without airflow cooling. Settings were 0.5-2.0 W for the continuous wave mode and 10-45 μJ, 20 kHz, 5-20 μs for the pulsed wave mode. The results show that the surface characteristics have a marked influence on temperature changes in response to irradiation. The TiUnite surface, corresponding to the osseous interface of dental implants, was the most susceptible to thermal rise, while the machined surfaces, corresponding to the implant collar, were less affected. In non-contact mode and upon continuous wave emission, the temperature rose above the 50 °C tissue damage threshold. Scanning electron microscopy investigation of surface alterations revealed that laser treatment in contact mode resulted in surface scratches even when no irradiation was performed. These findings indicate that the effects of diode laser irradiation on implant surfaces depend on physical features of the titanium coating and that in order to avoid thermal or physical damage to implant surface the irradiation treatment has to be carefully selected.

Red (635 nm), Near-Infrared (808 nm) and Violet-Blue (405 nm) Photobiomodulation Potentiality on Human Osteoblasts and Mesenchymal Stromal Cells: A Morphological and Molecular In Vitro Study

“…During the treatment, the temperature was recorded by a thermal probe included in the laser system console and monitored by a thermal camera (Ti9, Fluke Corp., Everett, WA, USA) showing a thermal map of the irradiated area (data not shown). The temperature remained unchanged during PBM treatments, as previously reported [ 84 , 85 ]. For the duration of PBM treatments, the cover cell culture plate was removed, and all the procedures were carried out under “clean bench” conditions to prevent contamination.…”

Potential Causes of Titanium Particle and Ion Release in Implant Dentistry: A Systematic Review

“…The authors demonstrated that while the used parameters did not change the treated surfaces, 3 W was 100% effective for surface decontamination [ 203 ]. The thermal effects of diode lasers (810 nm and 980 nm) when used at low energy (1 W) in pulsed mode with air/water cooling maintained the temperature below the critical threshold of 47 °C [ 204 , 205 , 206 ].…”

Using 445 nm and 970 nm Lasers on Dental Implants—An In Vitro Study on Change in Temperature and Surface Alterations

“…In the present study, no surface alterations were found for the 445 nm wavelength when radiating for 4 min at 2.0 W with a distance of 1 mm to the discs. Surface alterations on titanium discs and dental implants have been reported in other studies using different wavelengths, distances to the object, and power settings [12,13,14,21]. Romanos et al [12] showed that using Nd:YAG (1064 nm wavelength) at 2.0 W and 4.0 W in contact resulted in, as they describe it, melting and damage to the surface of the discs.…”

“…Previous studies done in vitro on temperature increases in and around dental implants have shown great discrepancies between different wavelengths of lasers [10,11]. Also, studies on alterations of the dental implant surface show conflicting results as to which wavelength of lasers should be used with limited risk for damaging the dental implant [12,13,14]. To our knowledge, no studies have yet looked at the potential deleterious effects of the 445 nm wavelength when directly irradiating a dental implant.…”