Unexpected radiopaque foreign bodies encountered in dental practice.

OBJECTIVES: The purpose of the present study was to determine the presence of radiopaque foreign bodies on oral and maxillofacial radiographs and classify them. METHOD AND MATERIALS: The Study Comment section of the Picture Archiving and Communication System of Chonnam National University Dental Hospital was searched using 30 key words to identify images with radiopaque foreign bodies recorded between November 2008 and March 2017. A total of 503 cases of radiopaque foreign bodies were selected from among the recovered images. The radiopaque foreign bodies were sorted into 19 types, which were subsequently divided into two categories according to whether the foreign bodies were inserted intentionally or unintentionally. The two categories were subdivided into five groups based on the cause of insertion: Treatment, Esthetics, Cultural, Iatrogenesis, and Accident. RESULTS: In this study, the proportions of foreign bodies inserted intentionally (48%) and unintentionally (52%) were similar. When the foreign bodies were grouped based on the cause of insertion, the following frequencies were observed: Treatment, 41%; Esthetics, 7%; Cultural, <1%; Iatrogenesis, 51%; and Accident, 1%. CONCLUSION: For adequate case management and to avoid unnecessary embarrassment and misinterpretation of unexpected radiopacities, clinicians should be familiar with the various types of foreign bodies and should ensure that detailed patient medical/dental history is obtained.

Benefits of lateral cephalogram during landmark identification on posteroanterior cephalograms.

OBJECTIVE: Precise identification of landmarks on posteroanterior (PA) cephalograms is necessary when evaluating lateral problems such as facial asymmetry. The aim of the present study was to investigate whether the use of lateral (LA) cephalograms can reduce errors in landmark identification on PA cephalograms. METHODS: Five examiners identified 16 landmarks (Cg, N, ANS, GT, Me, RO, Lo, FM, Z, Or, Zyg, Cd, NC, Ms, M, and Ag) on 32 PA cephalograms with and without LA cephalograms at the same time. The positions of the landmarks were recorded and saved in the horizontal and vertical direction. The mean errors and standard deviation of landmarks location according to the use of LA cephalograms were compared for each landmark. RESULTS: Relatively small errors were found for ANS, Me, Ms, and Ag, while relatively large errors were found for N, GT, Z, Or, and Cd. No significant difference was found between the horizontal and vertical errors for Z and Or, while large vertical errors were found for N, GT, and Cd. The value of identification error was lower when the landmarks were identified using LA cephalograms. Statistically significant error reductions were found at N and Cd with LA cephalograms, especially in the vertical direction. CONCLUSIONS: The use of LA cephalograms during identification of landmarks on PA cephalograms could help reduce identification errors.

Radiographic features of lingual mandibular bone depression using dental cone beam computed tomography.

OBJECTIVES: To describe accurately the radiographic characteristics of lingual mandibular bone depression (LMBD) using CBCT images. METHODS: This study included 30 cases of LMBD with CBCT images from 29 patients. Age, sex, location, shape, size, and the relationships of the LMBDs to adjacent anatomical structures such as the mandibular inferior cortex and mandibular canal were recorded. The correlation between age and size was evaluated using Pearson's correlation coefficient. RESULTS: The average age of the patients was 57 years. LMBDs occurred primarily in males (93%), occurrence in the right (n = 14) and left (n = 16) mandibles was approximately equal. The shapes were ovoid, round, peanut, triangular, or rectangular on panoramic radiographs. The occurrences in the molar, distal to the molar, and ramus regions were 63.3, 33.3, and 3.3% respectively. The mean size on CBCT was 15.4 mm in length, 11.2 mm in height, and 6.4 mm in depth. The relationship to the mandibular canal was categorized as separated (48.2%), contacted (31%), or go-through (20.7%). The relationship to the mandibular inferior cortex was classified as separated (20.7%), contacted (27.6%), or resorbed (51.7%). The Pearson's correlation coefficient showed a positive correlation between age and depth (r = 0.38; p = 0.038). CONCLUSIONS: The typical features of a LMBD were ovoid, round or mutilobated radiolucent shape, well-defined sclerotic border, and position in the posterior area of the mandible between the mandibular canal and inferior mandibular cortex. The buccolingual depth of LMBD was deeper with increasing age.