a b s t r a c tThe use of CO 2 laser has become a routine procedure for the treatment of oral leukoplakia. In this retrospective study, we evaluated 65 patients with oral leukoplakia treated with CO 2 laser vaporization. The main location was the tongue (n ¼ 21/65, 32.3%). The initial biopsy showed mild/moderate dysplasia in almost half the patients (n ¼ 29, 44.6%) and hyperplasia without dysplasia in around a third of the patients (n ¼ 21, 32.3%). The recurrence and malignant transformation rates were 33.8% (n ¼ 22) and 15.4% (n ¼ 10), respectively. The follow-up mean (standard deviation) was 15.0 (10.6) months. The procedure-related complications rate was 7.7% (n ¼ 5). The KaplaneMeier curves for time to recurrence showed differences only for gingiva lesions compared to tongue lesions (log rank, p ¼ 0.032). Malignant leukoplakia transformation is independent of treatment, although it seems advisable to treat leukoplakia with or without dysplasia.

Alveolar osteitis (AO) is a common complication after third molar surgery. One of the most studied agents in its prevention is chlorhexidine (CHX), which has proved to be effective. Objectives: The aim of this randomized double-blind clinical trial was to evaluate the efficacy of 0.2% bioadhesive chlorhexidine gel placed intra-alveolar in the prevention of AO after the extraction of mandibular third molars and to analyze the impact of risk factors such as smoking and oral contraceptives in the development of AO. Study Design: The study was a randomized, double-blind, clinical trial performed in the Ambulatory Surgery Unit of Hospital Vall d’Hebron and was approved by the Ethics Committee. A total of 160 patients randomly received 0.2% bioadhesive gel (80 patients) or bioadhesive placebo (80 patients). Results: 0.2% bioadhesive chlorhexidine gel applied in the alveolus after third molar extraction reduced the incidence of dry socket by 22% compared to placebo with differences that were not statistically significant. Smoking and the use of oral contraceptives were not related to higher incidence of dry socket. Female patients and the difficulty of the surgery were associated with a higher incidence of AO with statistically significant differences. 0.2% bioadhesive chlorhexidine gel did not produce any of the side effects related to chlorhexidine rinses. Conclusions: A 22% reduction of the incidence of alveolar osteitis with the application of 0.2% bioadhesive chlorhexidine gel compared to placebo with differences that were not statistically significant was found in this clinical trial. The lack of adverse reactions and complications related to chlorhexidine gel supports its clinical use specially in simple extractions and adds some advantages compared to the rinses in terms of duration of the treatment and reduction of staining and taste disturbance. Key words:Alveolar osteitis, dry socket, chlorhexidine bioadhesive gel, mandibular third molar surgery.