BackgroundSpecimen preparation for in vitro study suffers a general lack of methodological homogeneity, as well as a lack of uniformity in the materials selected for fabricating them. This situation prevents comparisons between studies. When a specimen is not of dental origin it is not possible to study adhesion or bonding techniques realistically. The objective is to design and implement a method of specimen preparation that permits universal standardization for use in in vitro studies.Material and MethodsA metal stump of specified dimensions was designed and fabricated by hand. It was scanned, the data digitalized, perfecting and standardizing the dimensions. Ten human molars were adapted to the size and shape of a standard milling block. A Cerec 3D inLab Cerec milling unit was used to prepare the molars to match the digitalized model.ResultsTen specimens with identical dimensions were obtained.ConclusionsCAD-CAM technology allows the preparation of natural extracted teeth to be standardized and could be used to establish a reproducible method that would facilitate comparison between different in vitro studies, and reduce bias arising from variations in sample fabrication. Key words:Test ceramic, dentin analog, dentin model, dentin samples, methodology.

BackgroundClassic self-curing temporary cements obstruct the translucence of provisional restorations. New dual-cure esthetic temporary cements need investigation and comparison with classic cements to ensure that they are equally retentive and provide adequate translucence. The objective is to analyze by means of traction testing in a in vitro study the retention of five temporary cements.Material and MethodsTen molars were prepared and ten provisional resin restorations were fabricated using CAD-CAM technology (n=10). Five temporary cements were selected: self-curing temporary cements, Dycal (D), Temp Bond (TB), Temp Bond Non Eugenol (TBNE); dual-curing esthetic cements Temp Bond Clear (TBC) and Telio CS link (TE). Each sample underwent traction testing, both with thermocycling (190 cycles at 5-55º) and without thermocycling.ResultsTE and TBC obtained the highest traction resistance values. Thermocycling reduced the resistance of all cements except TBC.ConclusionsThe dual-cure esthetic cements tested provided optimum outcomes for bonding provisional restorations. Key words:Temporary dental cements, cements resistance.