Dr. Louw uses OrthoCad™ as part of his treatment planning in an orthodontic treatment case. It is the newest in advanced orthodontics and offers more possibilities than ever before. In partnership with the American company Cadent, all study models are digitalized in 3D format. Patients and parents can see the whole movement of the teeth in 3D and the outcome can be seen even before the treatment has commenced.
The 3D digital study model
Dr. Louw uses Self Ligating brackets by choice. Easy opening and replacement when needed. Low friction. Saves up to 6 months on the treatment duration. Because of being self ligating, the result will be more pleasing and will fit the face better. The combination of indirect bonding and self ligating brackets speeds up the treatment considerably.
The treatment plan is discussed with each patient and the outcome may also be altered according to the wishes of the patient/ parent.
Central incisor’s clinical crown length is chosen. This causes the bracket (on the picture right) to move to a different position when the outcome is changed.
Accurate analyses like Bolton, Space, Moyers etc. are performed digitally.
Orthodontists uses various diagnostic methods to aid in the treatment planning and evaluation of an orthodontic case. Standard methods include study models, panorama x-ray, cephalometric x-ray with analysis and digital photo’s of patient profile and teeth. Dr Louw uses all of these methods digitalized in the treatment planning.
Application in the orthodontic practice
Because of the size of digital xray photos, advanced equipment has been developed to digitalize the images and make them available to photo editing software. Two systems are available. The direct system that uses CCD sensors and the less common CMOS sensors.
Figure. 1. Digital OPG machine for skeletal photo exposure
Frontal, lateral an panoramic photo taking for the fronto-lateral and horizontal planes. High resolutiondigital xrays with pixel quallity of approx. 300 pixels per mm2.
In comparison to the analog x-ray method, this digital device emits 50% less radiation.
The cephalometric analysis forms a very important role in the orthodontic treatment planning. On this analysis measurements of the profile, the ratio of the upper jaw to the lower jaw, the lip profile, inclination of teeth, jaw angle etc. Is measured. This will determine in which direction teeth will be moved and if any extractions are needed. The facial profile must be improved and not altered too much by the movement of the teeth.
The cephalometric analysis is performed on the lateral skeletal photo (ceph). It can be done by using a transparent piece of paper on top of a printed copy of the ceph or doing it with a software programme such as Kodak Orthotrac.
Digital tracing done with Kodak software. Fixed landmarks are used on the photo as seen above.
Digital photography is needed to capture the soft tissue character associated with the x-ray photos. A lot of detail can’t be portrayed by the x-rays and where the digital photos are used for.
Figure 3. Example of photos taken during treatment planning.
The value of study models, whether digital or plaster, lies in the three dimensional properties. The bite can be studied from all angles. Aspects which are not seen on photos. Measurements are performed on these models to determine space shortage/ excess and also discrepancies needed for accurate planning. Plaster study models take up a lot of practice space and this is where the digital model is superior
Fig. 4. Digital study models.
Fig. 4. b. By moving the mouse, the model can be moved in all directions around it’s own axis.
Coventional impression taking by means of an impression tray and material such as alginate or polyether is being replaced by digital scanning which does not cause gag reflexes and is more accepltable by children. A digital model can then be created immediately by means of CAD/CAM. The ideal bracket placement is selected and even the archwire can be bended by using robotic means (see figure 5)
Fig. 5. Orthodontic archwires being bended by a robot.
Dr. Louw also does a lot of orthodontic treatment on adults. The OrthoCad method forms a great part of the treatment, but Invisalign and Ormco SimplyFive are also offered. These systems are bracketless and consists of a series of transparent “overlays” which are worn at night to guide the teeth into the desired direction. These methods have limitations and can only be used in basic treatments and minor crowding.