## 1 Introduction  
Impacted teeth are often encountered during the diagnosis and treatment of malcolusions in adolescent orthodontic patients. After the third molars, the most commonly impacted tooth is the maxillary canine with an incidence of 0.9% to 2.2% [1; 2; 3], which varies depending on the ethnicity of the sample population.  
Although the canine crown can be impacted either labially or palatally, it is more frequently positioned in the palate.  
Of all patients who have impacted maxillary canines, 8% have bilateral impactions. They are more common in female than in male patients [4].  
Over the years, numerous researchers have focused on identifying the cause of impacted maxillary canines. The etiology of palatally impacted canines has been suggested as polygenic and multifactorial. There are two main theories: the genetic theory and the guidance theory [5].  
The therapeutic approach involves surgical exposure of the impacted tooth, followed by orthodontic traction to guide and align the tooth to the dental arch. For palatally impacted amines, various surgical approaches and various orthodontic traction techniques have been described in the literature [6]. There are two basic surgical methods for the exposure of a palatally impacted canine, the open and the closed technique. The open technique includes the surgical exposure of the crown by either complete removal of bone and soft tissue directly overlying the impacted canine and an orthodontic attachment is directly bonded on the canine in order to directly apply traction.  
The closed technique, on the other side, involves raising a full mucoperiostal flap, exposing the canine crown, and bonding an attachment on it. Afterwards, the flap is repositioned, and orthodontic traction is applied after initial healing, until the canine erupts in the oral cavity and is subsequently guided to the dental arch [5; 7; 8].  
Nowadays, laser technology has a more important role in modern dentistry and, in the last two decades, there has been an increase in research studies on many laser applications.  
The use of the laser offers several advantages when compared with conventional methods, including precision, minimal intraoperative hemorrhage, sterilization of the surgical area, healing with minimal scarring, and decreased post-operative pain and swelling [9].  
The aim of this study is to show the effectiveness of laser technology for the exposure of the crowns of palatally impacted amines, using a diode laser device ([PERSON], DMT, Lissone, Italy, 980 nm + 645 nm), without orthodontic device application to traction it.  
The hypothesis was that palatally impacted amines, after the laser surgery, will suffer a \"spontaneous\" eruption due to reactivation of the physiological eruption consequent to the laser stimulation and removal of the overlying tissue, without any orthodontic traction (traditional method).  
The literature reports significant studies on photobiomodulation (PBM) demonstrating the biostimulation effect provided by some wavelengths of this type of laser [10; 11; 12]. In PBM, an activation of regenerative and healing processes can be observed, as a consequence of the ability of subcellular photoreceptors to react to visible red and near-infrared wavelengths. Stimulation of these receptors influences the electron transport chain, the respiratory chain, and oxidation, expressed as an increase in the cellular metabolic processes [12; 13].  
Furthermore, the literature reports that high-intensity laser therapies (HILTs), \"surgical lasers\" having a cutting action on the soft tissues [14; 15; 16], can also be used successfully for opercolectomy, with the removal of soft tissue that overlies the impacted tooth.  
However, no study has evaluated the eruption-stimulating action when the laser is applied to expose the crown of impacted amines.