Utilising radiographic incisor crown markers to determine incisor inclination on headfilms an experimental study on extracted teeth /

by Dippenaar, Alfred Meyer.

UTILISING RADIOGRAPHIC INCISOR CROWN MARKERS TO DETERMINE INCISOR INCLINATION ON LATERAL HEADFILMS – AN EXPERIMENTAL STUDY ON EXTRACTED TEETH. ALFRED MEYER DIPPENAAR Supervisor: Department: Professor S.T Zietsman Orthodontics School of Dentistry Faculty of Health Sciences University of Pretoria Inaccuracy in landmark identification is regarded as the most important source of error in cephalometry. Better definition of landmarks should therefore contribute to better clinical decisions and research validity. This study primarily comprised of an ex vivo investigation on 50 extracted lower incisor teeth to determine whether radiopaque markers could be utilised to accurately assess lower incisor inclination. Fifty extracted lower incisor teeth were mounted onto a Perspex sheet. Radiopaque markers, manufactured from 1mm wide strips of lead film from used periapical radiographs, were attached to the crowns of the mounted teeth. A lateral cephalometric radiograph was taken in accordance to standard radiographic procedures (radiograph A). This showed the true inclination of the teeth. A second radiograph was taken with the roots obscured (radiograph B). Three observers traced the inclinations of the teeth on radiograph B (from incisor edge through the middle of the labio-lingual crownroot junction). The determination was done on two different occasions and the assessments compared with the true inclination. Comparative statistical analysis was applied to the readings and the results indicated that this method compared favourably with other methods to determine incisor inclination. In addition, clinical application of opaque markers to the teeth of patients demonstrated the following: it indicated exactly which tooth was being assessed, provided clear definition of the anatomical crown in the sagittal iv University of Pretoria etd – Dippenaar, A M (2003) plane and served as a constant reference point for clinical, study model and cephalometric measurements. Opaque radiographic markers on teeth can contribute to more accurate cephalometric measurements in orthodontics, leading to better diagnoses, treatment planning and research validity. Key words: orthodontics, lateral cephalometric radiographs, cephalometry, incisor inclination, radiographic markers, dental radiographic markers, determining incisor inclination. v University of Pretoria etd – Dippenaar, A M (2003)