The purpose of this study is to obtain experimental data on the possible changes that saliva may suffer when brought to low-level laser therapy protocols for analgesia in the masseter muscle, because this be on the Parotid salivary gland.

Climate: The study will be conduced by Lasertherapy and Photobiology Center (CELAFO) at the Institute of Research and Development at the University of Vale do Paraíba (UNIVAP), which was air-conditioned with temperature at 22 ° C.

Volunteers: 30 male volunteers aged between 18 and 30 years.

Flow Analysis Salivary pH and saliva buffer capacity before LLLT and after LLLT: Two consecutive samples of whole saliva were obtained from each second volunteer. The first, unstimulated total saliva (UTS) and the second of stimulated total saliva (STS). Obtaining mechanically given by chewing a paraffin 5cm² fragment. The gathering was held in the afternoon and with the patient in breakfast for at least one hour. All the volunteers were instructed not to brush teeth or use mouthwash for one hour prior to saliva collection of the experiment. The samples were collected UTS and STS requesting voluntary saliva deposited directly into a sterile universal collector. Salivary samples were compared by the universal table salivary flow described by Saliva samples were centrifuged at 1200 rpm for 10 minutes. All saliva volume produced during the 5-minute period was measured using test tubes recorded in milliliters. The pH was measured by a pH meter device. To test the buffer capacity, the saliva (3 mL) was placed in a Falcon tube containing 9 mL of 0,005 normal hydrochloric acid, subjected to manual shaking for 10 seconds, then maintained at rest for 10 minutes with open Falcon tube, aiming evaporation gases such as carbon dioxide which could interfere with the analysis. After 10 minutes the pH was measured with litmus tape aid compared with the color scale provided by the manufacturer.

Low Level Laser Therapy (LLLT): The investigators used the LLLT after the first collection of saliva, control therapies were applied, placebo LLLT red and LLLT in the infrared.The treatment was applied with an interval of 7 days in a randomized, controlled, double-blind, by drawing lots. Irradiation of LLLT was conducted in eight (8) points on the skin in the masseter region. The distance between points was 1cm. To know exactly the location of points, transparency sheets were used (irradiation feedback) and reference points of each volunteer, as follows: point 1 commissure eyelid, point 2 in the tragus of the ear and point 3 on the labial commissure.The anticipated period of 15 minutes to occur the desired effects of LLLT was performed new material collection.

Data Analysis: The salivary flow data, pH and buffering capacity of saliva was analyzed using a analysis program statistics with the nonparametric Kruskal-Wallis test. The significance level was 5% (p <0.05)

Inclusion criteria :

• Have all dental organs
• Male volunteers
• Age between 18 and 30 years
• Body mass index between 18.5 and 25 (normal) .

Exclusion Criteria:

Presence of problems that compromise the physiological activity of the masticatory system

• Neurological disorders
• Cerebral Palsy

parafunctions :

• Sucking fingers
• Nail biting
• Nibble objects
• Bruxism
• Mouth breathing .

Use of medication :

• Antihistamines
• Benzodiazepines
• Depressants of the central nervous system.

Temporomandibular dysfunction:

• Clenching of the teeth
• Bruxism
• Use of partial or full dentures .