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dc.contributor.advisorBoughner, Juliaen_US
dc.contributor.advisorPackota, Garneten_US
dc.creatorMarchiori, Denveren_US
dc.date.accessioned2015-01-17T12:00:16Z
dc.date.available2015-01-17T12:00:16Z
dc.date.created2014-12en_US
dc.date.issued2015-01-16en_US
dc.date.submittedDecember 2014en_US
dc.identifier.urihttp://hdl.handle.net/10388/ETD-2014-12-1883en_US
dc.description.abstractThird molar (M3) impaction is commonly observed in dental practice. While the causes of impaction are still not clearly understood, they appear to be multifactorial. Currently, an insufficient amount of space in the jaw distal to the second molar - the retromolar (RM) region - is considered to be the most significant of these putative risk factors. However, M3 eruption is not always guaranteed by space availability in the RM region, and other factors such as delayed M3 mineralization, tooth crown size, and dental arch size are suspected to increase impaction risk. Because studies have traditionally focused on mandibular M3s and been limited to two-dimensional (2D) radiographs, this study is the first to investigate the causes of M3 impaction in both jaws, using 3D imaging, with precision and accuracy not previously possible using standard 2D dental imaging modalities. This study tests the hypothesis that not only a reduced amount of space in the RM region is observed when M3 impaction is present but also delayed M3 mineralization, larger molar and premolar crowns, and shorter dental arches. Research ethics permission (BIO#11-202) was obtained to use existing retrospective cone beam computed tomography (CBCT) images of over 500 patients aged 8 to 24 years taken and curated at the College of Dentistry, University of Saskatchewan. Anatomical landmarks were defined and a proprietary software package, Xoran-CAT (Imaging Sciences International, Philadelphia, USA) was used to measure RM regions, molar and premolar crowns, and dental arch dimensions, as well as to score M3 mineralization status. Results were assessed using independent sample t-tests. When M3 impaction was present, both short RM regions and delayed M3 mineralization occurred in both jaws, indicating that both of these are risk factors for impaction. In the presence of M3 impaction, narrower dental arches were observed only in the maxilla, while larger premolar and molar crowns were seen only in the mandible. The observation of these last risk factors in distinct jaws when M3 impaction was present, suggests that these are secondary factors in the determination of the M3 impaction condition, and that standards of M3 impaction differ between upper and lower jaws.en_US
dc.language.isoengen_US
dc.subjectThird molar impactionen_US
dc.subjectetiologyen_US
dc.subjecteruptionen_US
dc.subjectpredictionen_US
dc.titleImpacted third molars: using 3D imaging to investigate the etiology of a common oral health concernen_US
thesis.degree.departmentAnatomy and Cell Biologyen_US
thesis.degree.disciplineAnatomy and Cell Biologyen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Science (M.Sc.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US
dc.contributor.committeeMemberCooper, Daviden_US
dc.contributor.committeeMemberEames, Brianen_US
dc.contributor.committeeMemberLieverse, Angelaen_US


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