A device and system for use in a root canal treatment, the device having a probe member and a handpiece for holding the elongate probe member, the probe member having an elongate distal portion capable of being accommodated in a root canal, said probe member comprising: at least one treatment channel having a distal opening in said elongate distal portion, said at least one treatment channel being configured for enabling operation of a suitable root canal treatment tool via said distal opening; at least one illumination channel comprising a first light guide having a first proximal end configured for optical coupling to a light source system, and a second distal end in said distal portion for illuminating internal regions of the root canal during operation of said device; at least one light collection channel comprising a second light guide having a first proximal end configured for optical coupling to an imaging system, and a second distal end located in said distal portion for collecting and transmitting light reflected from internal regions of the root canal to said proximal end during operation of said device. A number of methods for monitoring and carrying out various dental treatments are provided.