ortho - the international C.E. magazine of orthodontics

ortho1_201208 I I C.E. article_ application of 3-D imaging Post root-canal infection can be difficult to diag- nose with the standard periapical. The endodontic fillsmayappeartobenormaleventhoughotherclini- calfindingsandsymptomsareabnormal.Thepatient presents several months post root-canal treatment with pain on palpation and pressure and avoids this side of the mouth. A periapical radiogragh shows minimal pathol- ogy (Fig. 6). The roots appear to be filled and a small puffofsealerextendsthroughtheapexofthemesial roots.Thedistalrootstructureandfillappearnormal. There is little indication of periapical radiolucency only a widening of the periodontal ligaments of the mesial roots. ACBCTscanrevealsacompletelydifferentpicture. The coronal MPR reveals a short fill near the apex of themesiallingualrootandalargeradiolucency(Figs. 7, 8) not visible on the periapical radiograph (Fig. 6). Missed canals are difficult to see in a buccal- lingualprojectionoftheperiapicalradiographasone canal is superimposed on the other (Fig. 9). Often, as viewed in this radiograph, we see periapical pathol- ogy with an apparent normally filled canal. CBCT scans allow dentists to look for pathology in MPR planes to identify the actual problem before invasive procedures are performed on the patient. The axial viewshowsalingualcanalexistsandisuntreated.The coronal view confirms the diagnosis and treatment can be completed (Fig. 10). Today’s endodontists, as well as general dentists, are benefiting from the diagnostic capabilities of the high-resolution CBCT scanners available over conventional 2-D periapical.5,6 _Oral surgery Oralsurgery,withitsinherentinvasivenature,can be better served using CBCT with MPR as well as 3-D images.Theabilitytoperformvirtualsurgeryisaben- efit to both the doctor and the patient. Doctors have the advantage of seeing morphology and landmarks in real time and space with accurate measurements, and patients will gain a better understanding of the problemsandthesolutionstheirdoctorsareoffering them. Third-molar extractions can be risky based on 2-D and panoramic radiographs. These radiographs can often superimpose nerves and sinuses over root structures. Dentists using 2-D radiographs must of- tenrelyonexperiencetoassesstherisksofiatrogenic Fig. 6 Fig. 9 Fig. 7 Fig. 10 Fig. 8 Fig. 11 Fig. 6_Periapical showing minimal pathology with no radiolucency. Fig. 7_Coronal MPR showing a short fill on the mesial lingual and radiolucency. Fig. 8_Saggital MPR showing unfilled canal and radiolucency. Fig. 9_Periapical showing a normal fill with a radiolucency. Fig. 10_Coronal MPR showing the superimposed lingual root unfilled. Fig. 11_Coronal MPR showing nerve between roots of the third molar.