title: Nonionizing method of locating the apical constriction (minor foramen) in root canals.
abstract: The electronic method was evaluated as to its accuracy when used to determine the position of the apical constriction (minor foramen) in root canals. There were 39 vital and 8 nonvital teeth for a total of 47 specimens from 22 patients. The specimens were prepared with a Buehler Isomet bone saw to a thickness of 500 microns. Distances were measured and recorded with the use of a Bioquant II image analysis system. The electronic method appeared to measure a mean value of 0.2 mm coronal to the cemetodentinal junction in 47 canals where the apex locator was set at a reference setting of 40. When a frequency curve was plotted, it showed that the probability of being within 0.76 mm (1 SD) of the cementodentinal junction was 68%. This appears to correlate to where Kuttler indicated the minor constriction to be located. These devices seem to offer a unique method to locate the apical constriction and thus to ensure proper working length while reducing ionizing radiation.
authors.affiliation: Veterans Administration Medical Center, Allen Park.
authors.forename: T J
authors.initials: TJ
authors.lastname: Stein
authors.forename: J F
authors.initials: JF
authors.lastname: Corcoran
mesh_terms: D000368:Aged; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004553:Electric Conductivity; D004582:Electronics, Medical; D006801:Humans; D008875:Middle Aged; D009811:Odontometry / Q000379:methods*; D014092:Tooth Root / Q000033:anatomy & histology*