Essential oil extraction, preparation and composition sellectchem L. sidoides essential oil was prepared from leaves collected from the medicinal herb garden of the University of Fortaleza, Cear��, Brazil. Leaf essential oil was extracted using a modified Clevenger apparatus by the hydrodistillation technique.10,18 The volume of essential oil obtained was measured and the essential oil was stored in hermetically sealed glass receptacles with rubber stoppers, covered with aluminum foil to protect the contents from light, and kept under refrigeration at 8��C until use.10,18 The chemical composition was determined by gas chromatography�Cmass spectroscopy. The constituents were identified by a computer-based library search, using retention indices and visual interpretation of the mass spectra10,18.

The major constituents of essential oil were thymol (58.7%) and carvacrol (17.1%). Minor constituents included caryophyllene (10.3%) and p-cymene (8.98%). Preparation of the gels After extraction, 1 mL of the essential oil was diluted in 9 mL of ethanol (1:9), thus preparing a 10% mixture. As much as 50 g of carboxymethylcellulose was added to the L. sidoides infusion (1000 mL) and the mixture was kept boiling until its complete dissolution to obtain the 10% gel concentration. A glycerin/ethanol mixture (50mL:50 mL) was added and the solution was vigorously stirred for 15 min until gel formation occurred.22 Similar procedures were used to obtain a 2% chlorhexidine digluconate gel. Test and control gels The inert control gel was compounded so as to have color and taste similar to the test gels, and contained triethanolamine (q.

s.p.), ethanol, water (q.s.p.), methylparaben (0.2%), glycerin (2.5%), and aspartame (q.s.p.). The test gels had the same formulation, with 2% digluconate chlorhexidine or 10% L. sidoides essential oil added as appropriate. The control and test gels were compounded and packaged into bottles in the Pharmaceutics Laboratory of the University of Fortaleza. Bottles were pre-coded to ensure that neither the examiner nor the participants knew their content, which was revealed by the pharmacist only after the study was completed. In accordance with the parallel group design, subjects used only one of these gels throughout the study period. Experimental design Participants were assigned to either the control group (placebo gel, n=10) or the test groups, CLX (chlorhexidine gel, n=10) and LS (L.

sidoides-based gel, n=10), by random permutation of three. Participants were examined for plaque and gingivitis at baseline and after three months. A single, previously calibrated examiner scored Brefeldin_A the BI and the plaque index (PI)24, which were recorded on the buccal, mesial, distal and lingual surfaces of all teeth. The values of the four sites of each tooth were averaged to determine the BI and PI for each subject.