New imaging techniques in orthodontics Dr Ehsan Tavakoli DDs, OMFR

Imaging 2D: PA, Panoramic, Cephalometry, 3D: CT,CBCT,MRI

Cone beam CT a new imaging technique in maxillofacial imaging Synonyms: DVT,CBVI,CBVT,DCT CBCT is more popular

CBCT Currently, there are more than 47 CBCT systems from 20 different companies available commercially. There are big variations in the quality of the images and the radiation doses between most of these CBCT systems Units with reduced radiation doses and less powerful tubes are often associated with poor image quality

Various designs:

CBCT uses cone x-ray beam instead of fan beam in medical CT Scan( 180-360 degrees) Scan time 20-40 s

Specific Applications * Implant surgery * Orthodontic treatment planning * Jaw Tumor * Impacted teeth * Periodontal disease * Endodontic

Advantages of CBCT Fast scanning time Multiplanar reformation Inexpensive compared to CT Compatible with dentistry specified software (implant, orthodontics) The main advantage for the use of CBCT is that the clinician can get more accurate data from one scan than from the many 2D conventional radiographs traditionally used with less radiation exposure

MPR

CBCT in orthodontics

CBCT in orthodontics supernumerary teeth eruption disturbances the technique of choice for examining and localizing impacted teeth. TMJ analysis Airway study

impacted canines and their positional relationship to adjacent teeth

Dental development visualization in a mixed dentition

Softwares Dolphin (cephalometric analysis) InVivoDental (3D reconstruction) 3dMD (3D reconstruction)

3dMD software depicting the skeletal and soft tissues

Impacted canine

Digital study models(cast) Are introduced as the digital alternative to the traditional stone cast record. No need for impression taking They are easier and faster to obtain, to store Patients benefit from shorter appointment time provides superior treatment outcome

Digital study models(cast) Root shape, position, and angulations A gradual transition from the plaster models decade to the digital models is expected to occur in the near future.

3D cephalometry Cephalometric 2D images limitations : the difficulty in locating landmarks image distortion differences in magnifications(L-R), superimposition of the bilateral craniofacial structures and measurement errors

3D cephalometry CBCT produces images that are anatomically real-size 1:1 scale lack of superimposition of the anatomical structures. Lack of image distortion high precision of the linear and angular measurements (Kumar et al., 2007; Moshiri et al., 2007; Kumar et al., 2008).

3D cephalometry cephalometric planes are defined using three or four landmarks instead of the two landmarks used in 2D cephalometry allows for the evaluation of the right and the left sides of the skull independently(in facial asymmetry)

3D superimposition CBCT allows superimposition of images before and after treatment to evaluate the growth and treatment changes The 2D cepahalograms have been traditionally used to evaluate these growth or treatment changes based on stable anatomical landmarks. For example, the sella turcica for the cranial base registration and the mandibular canal for the mandible. 3D images provided easier and more accurate anatomical landmark registration

superimposition of the pre- (brown) and post - (blue) treatment skull models of a 12 years old patient treated with rapid maxillary expansion The use of different colors highlights the changes between the two scans

Superimposition: before(red) after(green)

3D facial photographs(stereophotogrammetry) soft tissue facial analysis evaluation of the craniofacial growth and development measurements of the aesthetic facial parameters

Image fusion registration of a 3D photograph upon a CBCT allow evaluation of soft and hard tissue simultaneously By changing the translucency of the image, the correlation between the facial soft tissues to the skeleton can be determined

Image fusion

changing the translucency of fused image

Thanks for your attention