The main objective of this study is to review and summarize recent findings on electroencephalographic patterns in individuals with chronic pain. We also discuss recent advances in the use of quantitative Electroencephalography (qEEG) for the assessment of pathophysiology and biopsychosocial factors involved in its maintenance over time. Data collection took place from February 2014 to July 2015 in PubMed, SciELO and PEDro databases. Data from cross-sectional studies and longitudinal studies, as well as clinical trials involving chronic pain participants were incorporated into the final analysis. Our primary findings related to chronic pain were an increase of theta and alpha EEG power at rest, and a decrease in the amplitude of evoked potentials after sensory stimulation and cognitive tasks. This review suggests that qEEG could be considered as a simple and objective tool for the study of brain mechanisms involved in chronic pain, as well as for identifying the specific characteristics of chronic pain condition. In addition, results show that qEEG probably is a relevant outcome measure for assessing changes in therapeutic studies.

Background:Photodynamic therapy (PDT) is a method of microbial reduction which can benefit periodontal treatment in areas of difficult access, such as deep pockets and furcations. The aim of this randomized controlled clinical trial was to evaluate the effects of PDT as an adjunct to full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis. Material and Methods:Twenty-two patients with at least one pocket with a probing depth (PD) of ≥7 mm and one pocket with a PD of ≥5 mm and bleeding on probing (BOP) on each side of the mouth were included, characterizing a split mouth design. The control group underwent full-mouth ultrasonic debridement and the test group received the same treatment associated with PDT. The PDT was performed on only one side of the mouth and the initial step consisted of subgingival irrigation with 0.005% methylene blue dye. Two minutes after applying the photosensitizer, the low power laser - AsGaAl (Photon Lase III - PL7336, DMC, São Carlos -São Paulo, Brazil) was applied (660 nm, 100 mW, 9 J, 90 seconds per site, 320 J/cm2, diameter tip 600 µm).The following clinical parameters were evaluated: plaque index, gingival index, BOP, gingival recession (GR), PD, and clinical attachment level (CAL). All parameters were collected before, 1, 3 and 6 months after treatment.Results:An improvement in BOP, PD and CAL was observed after treatment, in both groups, but without any difference between them. After 6 months, the PD decreased from 5.11±0.56 mm to 2.83±0.47 mm in the test group (p<0.05) and from 5.15±0.46 mm to 2.83±0.40 mm in the control group (p<0.05). The CAL changed, after 6 months, from 5.49±0.76 mm to 3.41±0.84 mm in the test group (p<0.05) and from 5.53±0.54 to 3.39±0.51 mm in the control group (p<0.05).Conclusion:Both approaches resulted in significant clinical improvements in the treatment of severe chronic periodontits, however, the PDT did not provide any additional benefit to those obtained with full-mouth ultrasonic debridement used alone.