The evaluation of nasolacrimal duct injury in Le Fort I osteotomy patients / Evaluación de la lesión del conducto nasolagrimal en pacientes con osteotomía Le Fort I

Background: Although Le Fort I surgeries are safe and successful procedures; nasolacrimal duct injuries may be observed due to these surgeries. The study aimed to investigate the prevalence of nasolacrimal duct injury in Le Fort I osteotomy patients. Material and Methods: The authors conducted a retrospective cohort study consisting of patients who underwent Le Fort I osteotomies between 2017 and 2021 in the Erciyes University Faculty of Dentistry. The primary predictor variables were the distance of the nasolacrimal canal to the outer cortex of the maxilla and the nasal floor, as well as the superior-inferior level of the superiorly positioned screw inserted in the maxilla aperture region relative to the nasolacrimal canal. The outcome variable was the presence of a nasolacrimal duct injury. Mann Whitney U test was used for quantitative variables between the two groups. A Pearson chi-squared analysis was used to compare categorical data. A p-value <0.05 was considered statistically significant.Results: A total of 290 nasolacrimal canals were evaluated in 145 patients, 87 females, and 58 males. The mean age was 23.47± 6.67. There was a statistically significant relationship between screw level and nasolacrimal canal perforation (p<0,001). The distance between the most anterior border of the nasolacrimal canal and the outer cortical of the maxilla was significantly less in the perforation group (p<0,001). The fixation screw was significantly closer to the nasolacrimal canal in the perforation group (p<0,001). Conclusions: In Le Fort I surgery, nasolacrimal duct injury may occur during screw fixation to the aperture region. Superiorly positioned fixation screws in the aperture region may damage the nasolacrimal canal. In patients where the nasolacrimal canal is close to the outer cortex, care should be taken when applying the fixation screws to the aperture region to avoid damaging the canal.(AU)

The effects of technical factors on the fractal dimension in different dental radiographic images.

Purpose: The aim of this study was to assess the impact of exposure parameters and image formats on fractal dimension (FD) values in periapical, panoramic, and CBCT images. Materials and methods: Seven dry male mandibles were selected, and a Gutta-Percha was used to identify identical regions of interest. A periapical radiograph was taken with 60 kVp/7 mA and exported in DICOM, JPEG, TIFF, and PNG formats. Nine periapical radiographs (60, 65, 70 kVp; 4, 5, 6 mA) were taken from seven dry human mandibles. Additionally, 12 panoramic radiographs (60, 70, 81, 90 kVp; 5, 8, 13 mA) and 10 CBCT images (with different scanning options and FOVs) were taken from each mandible. FDs were measured from a standard area. Results: The intra-class correlation coefficient demonstrated a high degree of agreement between observers. No significant difference was found between TIFF and PNG formats (p > 0.05). The highest FD mean was found in TIFF format, while the lowest FD mean was found in JPEG format (p<0.001). There was no significant difference between kVp and mA settings in periapical images. In panoramic images, a significant difference was found at 90 kVp (p = 0.001) and 13 mA (p<0.001), with lower FD values observed at these settings. There was no significant difference between FOV and resolution in CBCT images (p > 0.05). Conclusion: The format of the image can influence FD. For periapical and panoramic radiographs, kVp and mA settings do not have a significant impact on FD. However, fractal analysis may not be an ideal method for evaluating three-dimensional images, such as those obtained with CBCT.

Evaluation of chronic renal failure with cone beam computed tomography radiomorphometric indices and fractal analysis in the mandible.

OBJECTIVES: The purpose of this study is to evaluate the mandibular bone structure of patients with chronic renal failure (CRF) and compare to control group via the fractal analysis (FA) and radiomorphometric indices in the cone beam computed tomography (CBCT) images. METHODS: Three observers retrospectively investigated 44 CBCT images to compare patients with CRF to healthy controls. FA was performed in two different areas, volume of interests (VOI) were chosen in the mandibular ramus and corpus. The CT cortical index (CTCI), CT mental index (CTMI), and CT mandibular index (CTI) were performed to determine cortical porosity and thickness. The normality distribution of numerical data was tested using the Kolmogorov-Smirnova and Shapiro-Wilk tests. According to the results, the Mann-Whitney U test and independent group t test were used for parameters. The chi-square test was used to evaluate the distribution of categorical variables by groups. RESULTS: There were statistically significant differences in VOI1 and VOI2. The fractal dimension (FD) values in VOI1 and VOI2 were significantly lower in study group. There were no significant differences in CTCI, CTMI and CTI measurements between both groups. CONCLUSIONS: CRF is a prevalent cause of radiographic abnormalities in jawbones. The FD values in trabecular bone decreased in study group, although there were no significant differences in the radiomorphometric indices. FA in CBCT images could be useful for a three-dimensional evaluation of trabecular bone structure.

Effects of conventional complete dentures and implant-supported overdentures on alveolar ridge height and mandibular bone structure: 2-year and 6-year follow-up study.

OBJECTIVES: The aim of this study was to compare the changes in mandibular bone structure in edentulous patients who were rehabilitated with conventional complete dentures (CCD) and implant supported overdentures (ISO), by evaluating alveolar bone loss (ABL), panoramic mandibular index (PMI), mandibular cortical width (MCW), gonion index (GI), antegonial index (AI), and articular eminence inclination (AEI). MATERIALS AND METHODS: Panoramic radiographs of 63 edentulous patients using CCD, 63 edentulous patients using ISO, and 126 patients without tooth loss were evaluated. Edentulous patients had a 2-year and 6-year follow-up panoramic radiograph image. ABL (anterior, premolar, and molar regions), MCW, PMI, AI, GI, and AEI were measured in each patient. Variation between measurements was analyzed using repeated measures ANOVA test and post hoc Tukey test. RESULTS: Both edentulous groups showed significantly lower mean than without tooth lost group in all measures (p < 0.000). ISO group showed significantly lower mean ABL than CCD group in anterior (p = 0.000), right premolar (p = 0.005), left premolar (p = 0.005), right molar (p < 0.000), and left premolar (p < 0.000) regions in short term. ISO group showed significantly lower mean ABL than CCD group in anterior (p = 0.021), right molar (p < 0.000), and left premolar (p < 0.000) regions in long-term. There is no statistically significant difference between the CCD and ISO groups in right premolar (p = 0.200) and left premolar (p = 0.134) regions in long term. Both edentulous groups showed significantly lower mean MCW (p < 0.000), PMI (p < 0.000), AI (p < 0.000), GI (p < 0.012), and AEI (p < 0.002) than the without tooth loss group. There is no statistically significant difference between the CCD and ISO groups in terms of changes in the mean MCW, PMI, AI, GI, and AEI measurement in short and long term (p > 0.000). CONCLUSIONS: In the short and long term, edentulism reduced alveolar crest height, MCW, and AEI in individuals, but had no effect on PMI, AI, or GI. The use of prosthesis did not prevent the decrease of alveolar crest height, MCW, or AEI (CCP or ISO). In the short and long term, however, ISO created less ABL in the mandibular anterior and molar regions than CCD. CLINICAL RELEVANCE: ABL cannot be halted in edentulous people, but by using ISO instead of CCD for rehabilitation, resorption can be reduced.

Fractal properties and radiomorphometric indices of the trabecular structure of the mandible in patients using systemic glucocorticoids.

OBJECTIVES: The aim of this study is to evaluate the mandibular trabecular and cortical bone structure of patients using systemic glucocorticoid (GC) and compare to control group with the fractal analysis (FA) and radiomorphometric indices. METHODS: Two researchers retrospectively investigated 192 dental panoramic radiographs to compare individuals using systemic GCs to healthy controls. FA was performed in 4 different regions; geometrical center of the mandibular ramus (ROI1), cancellous bone on supracortical mandibular angle area inferior to the mandibular canal (ROI2), cancellous bone on mesial to the mental foramen (ROI3), basal cortical bone extending mental foramen to the first molars' distal root in the mandibular corpus (ROI4). Panoramic mandibular index (PMI), mandibular cortical width (MCW) and mandibular cortical index (MCI) were performed for evaluate cortical thickness and porosity. The Shapiro-Wilk test was used to determine the normal distribution of the data, the independent t test for comparison of values and the chi-square test for descriptive statistics. RESULTS: There were statistically significant differences in ROI4 and MCW. The fractal dimension (FD) values in ROI4 and MCW were significantly lower in study group. There were no significant differences in FD values in ROI1, ROI2, ROI3 and PMI and MCI measurements between both groups. CONCLUSIONS: FA and radiomorphometric measurements is an efficient method to detect early changes in bone mass. In our study, ROI4 and MCW were significantly lower in study group. Osteoporosis prevention should be considered in patients using systemic GCs.