1. In a toothbrush having a head, a neck and a handle, the improvement comprising the handle including a first portion coupled with the neck, and a second portion removably coupled with the first portion at an end of the handle that is furthest from the head and shorter in length than the first portion of the handle, and at least one passive marker located at the second portion of the handle and configured to aid in tracking by a computing device of a brushing trajectory, wherein the second portion is marked using two tags, wherein each of the tags is one of an augmented reality (AR) marker, a bar code, and a quick response (QR) code.