4th Generation of Apex Locators

The Ray-pex 5 by DENTSPLY is the latest version of the successful Ray-pex line of apex locators. It is characteristically compact and has a small “footprint” on the
bracket table or surgery work surface.

It is a “4th generation” apex locator that has a new mathematical algorithm that allows the unit to determine the position of the major apical constriction in the root canal. In clinical practice, this facility appears to work well and is a very useful additional piece of information that the apex locator can provide.
The Ray-pex 5 comes with two types of electrode for connecting to endodontic files. The clip-type electrode for areas was access is straight forward and the probe-type where access is difficult or a limited amount of file shaft is available for connection.

As with all modern apex locators, the unit will work in canals containing all types of fluid. However, it is advisable to have canals moist rather than flooded with sodium hypochlorite, so as to avoid wild fluctuations in readings. Furthermore, the unit is most accurate when the size of the test file in the canal approximates the diameter of the apical foramen. It was found that the following protocol is useful when measuring working length:
Carefully determine the length at which the test file touches the periodontal ligament (“True” working length)

A note should be made in the patient’s clinical record of this length. The test file is then carefully withdrawn until the display indicates the file tip is at the major constriction of the root canal.
During instrumentation of the root canal, recapitulation files should be set to the “True” working length (or 0.5mm longer, if preferred). With all rotary instrumentation, the working length should not exceed the position of the apical constriction. This way, the preservation of the natural resistance form of the root canal is maintained and extrusion of root canal filling materials minimized.
Measurements were made of the “true” working length of the root canals and the length at which the apical constriction was detected. No rotary instrumentation was taken beyond the length of the apical constriction. The tooth was prepared using “ProTaper” rotary files to a size F2 in the mesial root canals and F3 in the distal root canal. Gutta percha cones were adjusted at the “try in” stage until they fitted the length of the root canals as measured to the apical constriction


The Ray-pex 5 is an efficient, compact and accurate apex locator that incorporates the latest mathematical algorithms to calculate the position of the apical constriction within the canal which is a useful feature in clinical practice. It is a great new unit which is definitely recommended.’
instructions for use