A data set of proximity of mandibular third molar roots with Inferior Alveolar Canal.
OPG’s are inexpensive, low radiation and easily available in smaller dental units and hospitals also however, a real three-dimensional picture and buccolingual relationship is unknown. Dearth of studies on third molar roots and inferior alveolar canal in Nepalese population persuaded us to carry out this study to describe the proximity of mandibular third molar roots to the inferior alveolar canal and nerve. A single centre cross-sectional study was designed with sample size of 475 patients collected from July 2017 to July 2019, at the department of Oral and maxillofacial surgery of College of Medical Sciences and Teaching Hospital (COMS-TH), Bharatpur, Nepal. Ethical approval was obtained from institutional review committee of COMS-TH. All the patients who reported the signs and symptoms of third molar pain and difficulty were included. Pregnant patients and those who didn’t provide consent were excluded. Orthopantomogram (OPG) of patients were retrieved from imaging software records. Baseline demographic data was obtained from patient’s entry in OPG imaging software program (Orthoralix Vixwin software) and signs of proximity of mandibular third molar roots to inferior alveolar canal as described by Rood and Shebab were ascertained. The seven radiographic signs were observed on digitally magnified OPG’s using Orthoralix Vixwin software (Gendex, USA) and presence or absence of signs were entered. Presence of simultaneous multiple signs were entered. Explicit prior criteria have been used to designate each of the seven panoramic radiographic signs as “positive” when present or “negative” when absent. All observations and demographic datas were entered in Microsoft excel and descriptive analysis was performed with SPSS Version 20. Frequency was used to describe presence of radiographic signs and means were used to describe demographic variables. Cross tabulation was done to analyse the pattern of combination of signs. One or more radiographic signs were observed in 49.6% of mandibular third molars. Interruption of white line followed by narrowing of canal and darkening of roots was observed in decreasing order of frequency and no statistically significant association between sex, age and side of impacted third molar with presence of radiographic signs. Absence of any radiographic sign was observed in 245 cases (51.6%). When only one sign was observed (n=71), the most common sign was, interruption of white line of canal followed by deflection of roots. The next most common pattern of combination was 3 signs (n=60) followed by two signs together (n=55).
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Criteria for presence or absence of radiographic signs on OPG was manually performed by the two individual authors and if there was a disagreement, a third investigator was involved to resolve the issue. The presence of each sign on the radiograph was assessed based on the criteria given by Rood and Shebab.