**2. Advantages of Er: YAG laser treatment**

Laser technology has certain advantages such as accuracy of the incision, absence of vibration and manual pressure during use; this is also true for Er: YAG laser application. Due to laser positive coagulation effects during surgical procedure, better sight of the work field is obtained. Komori [4] and Gouw-Soares [5] have reported that Er: YAG lasers are appropriate for the treatment of hard dental tissues without inducing discomfort, vibration or noise. Furthermore, risk of surgical field contamination and damage to the surrounding tissues is decreased when compared to the other similar techniques. Additionally Er: YAG lasers are characterized by low intraoperative and postoperative pain levels. Decreased pain levels by use of Er:YAG as well as other lasers may be explained by the fact that laser application leads to the formation of protein coagulum on the surface of the wound which acts as a dressing [6]. Furthermore, lasers have the ability to seal sensory nerve endings which results in decreased pain perception. Last but not least, Er: YAG lasers produce rapid wound healing [7].

## **3. Possible hazards of laser use**

It is very important to acknowledge possible thermal damage induced by Er: YAG lasers in the clinical setting. Kreisler [8] suggested that temperature elevation did not exceed 47°C after 120 seconds of Er:YAG laser irradiation with pulse energy between 60 and 120 mJ and frequency of 10 Hz. Geminiani [9] reported that application of Er:YAG lasers in continuous mode for 10 seconds generated a high temperature which was above critical threshold. Monzavi [10] reported that use of Er: YAG was safe without cooling and that, an increase of 4.30°C was observed. Use of air and air water cooling eliminated the risk of possible thermal damage. Mitsunaga [11] retrieved literature data from the year 2001 to 2012 with regard to complications after laser irradiation such as cervicofacial subcutaneous emphysema. They [11] reported 13 such cases, of which eight had undergone CO2 laser treatment and two had undergone Er: YAG laser treatment. Nine patients had emphysema following laser irradiation for soft tissue incision [11].
