An image guidance system for tracking a surgical instrument within an oral cavity comprising: an oral fixture configured to be removably attachable to a patient's teeth or bone inside the patient's oral cavity and at a location spaced away from a surgical area; a reference fixture that is attachable to the patient's teeth or bones within the oral cavity separate from the oral fixture, wherein a reference pattern is formed on an outer surface of the reference fixture; a plurality of cameras (30, 105) configured to be located within the oral cavity, the plurality of cameras configured, when activated, to provide intraoral images of optically visible patterns within the oral cavity; a surgical instrument to be tracked, a tool fixture being attached to or formed integral with the surgical instrument; wherein the plurality of cameras includes at least one camera attached to the tool fixture of the surgical instrument to be tracked and at least one camera attached to the oral fixture; a processing system configured to process the intraoral images and configured to recognize patterns and triangulate the locations and orientations of each camera, the camera attached to the oral fixture being configured to capture image reference data provided by the reference pattern and to relay the reference data to the processing system during use for determining the movement of the camera and, thus thus, the oral fixture; wherein the camera attached to the surgical instrument is mounted so that, when the surgical instrument is positioned within the mouth, the camera is oriented toward the reference pattern on the reference fixture; wherein the camera attached to the surgical instrument is configured to relay the image of the reference pattern to the processing system; the processing system programmed to receive a reference dataset comprising stored data of a location and orientation of the oral fixture in the oral cavity and the camera relative to the oral fixture, and stored data of the location of the camera attached to the surgical instrument, the reference dataset defining a reference coordinate system rigidly aligned to a portion of the oral anatomy; the processing system being programmed to calculate the actual movement of the oral fixture using the image of the reference pattern and the stored data on the location of the oral fixture; the processing system being configured to determine the location and orientation of the tracked instrument based on the image reference data provided by the reference pattern and the stored data of the location of the camera attached to the surgical instrument. an oral fixture configured to be removably attachable to a patient's teeth or bone inside the patient's oral cavity and at a location spaced away from a surgical area; a reference fixture that is attachable to the patient's teeth or bones within the oral cavity separate from the oral fixture, wherein a reference pattern is formed on an outer surface of the reference fixture; a plurality of cameras (30, 105) configured to be located within the oral cavity, the plurality of cameras configured, when activated, to provide intraoral images of optically visible patterns within the oral cavity; a surgical instrument to be tracked, a tool fixture being attached to or formed integral with the surgical instrument; wherein the plurality of cameras includes at least one camera attached to the tool fixture of the surgical instrument to be tracked and at least one camera attached to the oral fixture; a processing system configured to process the intraoral images and configured to recognize patterns and triangulate the locations and orientations of each camera, the camera attached to the oral fixture being configured to capture image reference data provided by the reference pattern and to relay the reference data to the processing system during use for determining the movement of the camera and, thus thus, the oral fixture; wherein the camera attached to the surgical instrument is mounted so that, when the surgical instrument is positioned within the mouth, the camera is oriented toward the reference pattern on the reference fixture; wherein the camera attached to the surgical instrument is configured to relay the image of the reference pattern to the processing system; the processing system programmed to receive a reference dataset comprising stored data of a location and orientation of the oral fixture in the oral cavity and the camera relative to the oral fixture, and stored data of the location of the camera attached to the surgical instrument, the reference dataset defining a reference coordinate system rigidly aligned to a portion of the oral anatomy; the processing system being programmed to calculate the actual movement of the oral fixture using the image of the reference pattern and the stored data on the location of the oral fixture; the processing system being configured to determine the location and orientation of the tracked instrument based on the image reference data provided by the reference pattern and the stored data of the location of the camera attached to the surgical instrument.