The aims of this paper were to critically review the role of radiographic imaging before lower third molar removal and to suggest a strategy for preoperative imaging based on available scientific evidence and clinical experience. Original articles and reviews including the MESH terms "third molar" and "radiography" were selected from the Medline database. Other sources were taken from references of selected papers. It was found that the scientific evidence on the usefulness of different preoperative imaging techniques of wisdom teeth is low. Therefore, information gathered from the literature was combined with the authors' clinical experience to suggest a strategy for preoperative imaging of lower third molars. Currently available radiological techniques used for preoperative imaging of lower third molars are also presented. It is suggested that panoramic and/or intraoral radiographs are sufficient as preoperative imaging in the vast majority of cases where there is no overlap between the mandibular canal and the wisdom tooth. Supplement with a posteroanterior open mouth projection will solve most of the remaining cases. In a restricted number of cases where there is an intimate relationship between the mandibular canal and the wisdom tooth, volume tomography such as cone beam computed tomography or low-dose computed tomography is indicated.

PostprintThis is the accepted version of a paper published in Dento-Maxillo-Facial Radiology. This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination.Citation for the original published paper (version of record):Ohman, A., Kivijärvi, K., Blombäck, U., Flygare, L. (2006) Pre-operative radiographic evaluation of lower third molars with computed tomography.. Objectives: To report radiographic findings of examinations with computed tomography (CT) of impacted lower third molars with an intimate relation to the mandibular canal and to investigate how findings of a dark band across the roots of the lower third molar on panoramic views correspond to the CT findings. Methods: CT images of 90 lower third molars (64 patients, mean age 34.6 years) in which plain radiography was insufficient to allow determination of the precise anatomical relations were reviewed retrospectively. Panoramic views of 88 teeth existed; these images were interpreted independent of the CT examinations with respect to presence of a dark band across the roots. Results: In 31% of the CT images, the course of the mandibular canal was buccal, in 33% lingual, in 26% inferior, and in 10% inter-radicular. The tooth was in contact with the mandibular canal in 94% and with the lingual cortex in 86%. In 23%, grooving of the root by the canal was judged to be present. In 63% of the cases where a dark band across the roots was observed on panoramic radiographs, CT revealed grooving of the root. Conclusions: Pre-operative CT of lower third molars is motivated in selected cases when plain radiography is inconclusive. The finding of a dark band across the roots on panoramic radiographs is an indicator of grooving of the tooth by the canal and justifies a pre-operative CT examination. The absence of dark bands on panoramic views does not exclude grooving of the roots. Dento

ObjectivesThis study sought to investigate the proportion of patients with suspected sinusitis referred for radiological examination who have radiologically verified sinusitis of odontogenic origin and to describe this type of sinusitis.Study DesignThis investigation is a retrospective study.MethodsA total of 303 sinus examinations involving cone beam computed tomography (CBCT) performed at Sunderby Hospital, Luleå, Sweden in 2012 were independently reviewed by two radiologists. The number of cases of maxillary sinusitis and the correlation between maxillary sinusitis and odontogenic infections were determined.ResultsOverall, 24% of the verified cases of sinusitis were odontogenic. An odontogenic origin was identified in 40% of unilateral maxillary sinusitis cases but only 6% of bilateral maxillary sinusitis cases (p = 0.0015). Forty‐nine out of 54 patients with periapical destruction had adjacent mucosal swelling in the maxillary sinus, but only 15 of these patients satisfied the criteria for sinusitis.ConclusionThe present study confirms the close relationship between odontogenic infections and unilateral maxillary sinusitis. Level of Evidence 4

The effective dose is low when CT examination with exposure factors optimized for the examination of bone structures is performed. However, the dose is still about four times as high as for CR without tomography. CT should therefore not be a standard method for the examination of lower third molars. In cases where there is a close relationship between the tooth and the inferior alveolar nerve the advantages of true sectional imaging, such as CT, outweighs the higher effective dose and is recommended. Further reduction in the dose is feasible with further optimization of examination protocols and the development of newer techniques.

The endodontists in this study exhibited a low degree of agreement when choosing a treatment for root-filled maxillary molars with apical periodontitis. A CT examination of the investigated teeth did not result in a significantly higher degree of agreement, and CT frequently contributed to a shift in the selected therapy.