Deviation of the major apical foramen from the anatomical root apex is a recognized phenomenon. To determine the frequency, position and mean distance of the major apical foramen from the anatomical root apex, 230 roots of permanent teeth were examined stereomicroscopically and radiographically. Radiographic analysis was used to establish how accurate the conventional radiograph was in displaying such a deviation. The frequency of deviation of the major foramen, determined stereomicroscopically, was 76%, and depended on the type of teeth examined. Radiographic analysis of the same sample revealed 57% of root canals had asymmetry of the root canal foramen. Agreement of stereomicroscopic and radiographic findings was found to be 61%. The most frequent deviation of the major foramen was on the distal root surface (29%), but this was not statistically significant. The mean distance between the deviation of the major foramen and the anatomical root apex was 0.99 mm. The study indicates that the clinician should consider deviation of the foramen during root canal treatment, as the deviation could not easily be detected radiographically.

The study evaluated secular trends in dental development during a period of 30 years, correlation between dental and chronological age in Istria and the littoral region of Croatia. The sample consisted of 1000 panoramic radiographs of children, aged 6-16 years (mean 10.0±1.8), taken in the period 1977-1979 (N=500; 243 females) and 2007-2009 (N=500; 299 females). Dental age was assessed according to Demirjian's method. Correlation between chronological and dental age was linear, positive, high, and statistically significant in both periods and genders, ranging from 0.73 to 0.86. Dental age was underestimated when compared to chronological age by 1 year on average, more 30 years ago (-1.35±1.17) than today (-0.63±1.09), less for girls (-0.80±1.22) than boys (-1.21±1.10). A statistically significant positive secular trend in acceleration of dental development was present of 0.72 years during the 30-year period and was more significant in girls than boys (0.83- and 0.51-year acceleration).

The objective of this research was to develop a technique that would allow three-dimensional imaging of root canals utilizing computer image processing. Ten single-rooted permanent human teeth with mature apices were analysed. The teeth were decoronated and fixed on boards with the long axis of the root perpendicular to the board. The cross-sectioning started at the root apex and continued in the coronal direction, roughly perpendicular to the long axis of the ++root. The samples were divided into two groups. The first five samples were sectioned 15 times, each section being 0.5-mm thick, in order to obtain the three-dimensional reconstruction of the root and the root canal. The root apex of each sample was cross-sectioned 19 times and each section was 0.2-mm thick. After each section, the root canal contour was defined utilizing the calibrated net with coordinate system in the ocular of the stereomicroscope. The coordinates of the root canal cross-section contour thus determined, together with the value of the thickness of each cut, were relevant input data for the reconstruction of the root canal cross-sections, longitudinal sections and for the final three-dimensional rebuild of the root and the root canal model. this technique appears to be highly accurate in determining the anatomy of the root canal system and may also be applied in other fields of dental research.

Overall, asymmetries in mixed dentition cannot be considered rare; however, no strong relationships between asymmetry and observed biological factors were found.

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