The aim of this study was to quantify the mineral content removed from primary teeth after using a chemomechanical system, called Papacarie®. Materials: Twenty human primary extracted molars were divided into two groups of 10 specimens each. Group A presented sound molars and Group B decayed molars on the occlusal or occlusal-proximal surface. In Group A, cavities in enamel and dentin with high speed drills were made before treatment. All teeth were treated with Papacárie® following the manufacturer's instructions. Each cavity was filled in with the product, allowing curing for 45 seconds, and then removed with the noncutting edge of the curette. The collected material was sent for laboratory analysis using atomic absorption spectrophotometry technique. Medians for each group were calculated through the application of Mann-Whitney and a statistically significant difference (p <0005) was observed. To verify the quantity of calcium removed from sound tissue, the median of calcium in group A (0.08% Ca) was compared with that of the gold standard (0.04% Ca), which showed a close correlation of values between them. Results indicate that the amount of calcium removed with Papacárie® affects only the carious component of teeth. This goes in accordance with the principles of cavity preparation and follows the current philosophy of preventive dentistry.

Funding Acknowledgements Type of funding sources: None. Main funding source(s): Alfredo Aurélio Marinho Rosa and Alfredo Aurélio Marinho Rosa Filho Background Heart failure (HF) is a serious, progressive disease, caused by ventricular dysfunction, leading to a worsening in quality and a reduction in life expectancy. Cardiac resynchronization therapy through multisite stimulation has become an important tool in the treatment of advanced HF, however, due to anatomical variations and even the absence of appropriate veins for the insertion of the left ventricular electrode, the access of the middle cardiac vein can be an option for biventricular cardiac stimulation. Objective: To present the technique used to access the middle cardiac vein (MCV) for the implantation of the left ventricular electrode and the results of this multisite stimulation. Material and Method: Between March 2006 and May 2016, 388 patients (PT) underwent biventricular stimulation (BIV) at our service. 276 PT (71.1%), were associated with the cardioverter-defibrillator (ICD), 226 PT (58.2%) were male and their age ranged from 28 to 84 years with an average of 64 years. In this group, in 63 PT (16.2%) the left ventricular electrode was implanted through CMV. The technique initially consists of introducing a deflectable catheter for marking the coronary sinus (SC) via the femoral approach, then the SC approach is performed by puncturing the left subclavian vein, introducing an 8F sheath up to the proximal 1/3, where the VCM venogram is performed by introducing a 0.014 "guide wire and the 5 F bipolar or quadripolar electrode, then defining the best electrode position from the smallest stimulated QRS. Results: In this group of 63 PT, 52 PT (82.5%) responded to cardiac resynchronization therapy. The most frequent cardiopathies involved were ischemic (38%), chagasic (25%), hypertensive (12%) and others (25%). The thresholds varied from 3.5 to 0.5 V, impedance from 600 to 1200 ohms and sensitivity between 10 and 20 mV. There were no complications in the trans or post implant and in 5 PT (7.9%), there was phrenic stimulation. The procedure time varied from 50 to 180 minutes. Conclusion: Multisite stimulation through the access of the middle cardiac vein proved to be a possible alternative, easy to perform and with a high PT index responsive to cardiac resynchronization therapy.