A stereomicroscopic study of the root apices of 400 maxillary and mandibular anterior teeth.

T HE object of this study is to increase our knowledge in the field of endodontics through critical examination of tooth apices and to organize the findings in a definite statistical form. This study of 400 anterior teeth is a continuation of my previous research dealing with the root apices of 100 mandibular molars. It was extended to anterior teeth as a result of the great interest exhibited in the original investigation. A study of the apical areas of teeth is of major importance, inasmuch as it involves the gateway of the circulatory and nervous systems of teeth. The use of the stereomicroscope allowed precise visualization of the many variations in the morphology of the apex and foramina. As in the previous study, the Bausch and Lomb senior model BKT-5, a stereoscopic wide-field microscope, was used; illumination was provided by a Nicholas illuminator. This instrument, adjustable for various positions, gives a most intense spotlight effect. Its easily adjustable condenser system efficiently concentrates brilliant intense light on a small area, or evenly distributes it over large fields of view. A blue daylight filter, the nearest approximation to daylight, was used. The intensity of light is adjusted by a transformer. Measurements were made with a calibrated micrometer disk, inserted into a specific receptacle in the eyepiece. These calibrations were viewed superimposed on the magnified specimen. A millimeter ruler was placed on the stage. The number of calibrations in the eyepiece superimposed on 1 mm. of the ruler was noted. For example, if there were twenty divisions on the eyepiece to 1 mm, on the stage ruler, we recognized that each division was equal to l/20 or 0.05 mm. on the specimen.