Objectives: (1) to calculate association between trabecular bone density by computed tomography (CT) in potential implant sites from original axial DICOM images (DentaCT) and measurements on the same images after electronic transfer to a PC compatible software (eFilm workstation), (2) to correlate trabecular bone density in Hounsfield units (HU) with Lekholm and Zarb's bone quality classification (1985), and (3) to establish a quantitative scale for this bone quality classes. Methods: Twenty-seven maxillary and 27 mandibular CT scans from 51 patients examined before implant treatment were selected. Measurements of trabecular bone density were performed in 75 potential anterior and posterior implant sites, using both softwares. A classification of bone quality according to Lekholm and Zarb (1985) was made independently by two observers based on reformatted sectional images of all selected sites. Results: The range of mean HU values obtained by DentaCT was 383.17 to 255.55 and using eFilm 342.00 to 240.4. A strong correlation (r = 0.95; p = 0.00) was found between measurements from both softwares and the jaws presented wide ranges of HU values. A significant correlation was observed between HU values and quality scores (rs = 0.543, p=0.00 – DentaCT; rs = 0.515, p=0.00 – eFilm). Quantitative parameters in HU ranged as follows: bone type 4 <200 HU; type 2 and 3 >200 to <400 HU; and type 1 >400 HU. Conclusions: Both softwares provided similar trabecular bone density information. Previous evaluation of individual implant sites must be emphasized since any bone type could be found among the different regions studied.