Effect of different cone beam computed tomography settings on artifact production in titanium and zirconia dental implants: An in vitro study.

BACKGROUND: The use of dental implants in the treatment of edentulous patients is increasing. Zirconia implants are an alternative to titanium implants, offering advantages in terms of aesthetics and biological compatibility. However, the number of artifacts observed on radiographic images with zirconia implants compared to titanium implants is yet to be determined. OBJECTIVES: The purpose of this study was to evaluate the impact of different cone-beam computed tomography (CBCT) parameters on the production of artifacts in zirconia and titanium implants. MATERIAL AND METHODS: A dry human mandible was coated with wax to simulate human soft tissues and examined. Subsequently, titanium and zirconia implants were placed at the same points in the posterior region of the mandible. The production of artifacts on CBCT scans was evaluated using 2 parameters. The first parameter, the standard deviation within the region of interest (SDROI), is based on a comparison of the gray levels at implant and control areas. The second parameter was the contrast-to-noise ratio (CNR), which was evaluated for different protocols created by various combinations of the field of view (FOV) area, milliampere [mA] intensity and metal artifact reduction (MAR) programs. RESULTS: The study found that zirconia implants produced more artifacts than titanium implants. However, the production of artifacts in zirconia implants could be significantly reduced by increasing the mA values, performing CBCT scans with smaller FOV areas, and enabling MAR programs. CONCLUSIONS: The production of artifacts is a disadvantage of zirconia implants, but this drawback can be mitigated by selecting appropriate protocols for the CBCT device.

Third molar maturity index (I3M) assessment according to different geographical zones: a large multi-ethnic study sample.

Identification of living undocumented individuals highlights the need for accurate, precise, and reproducible age estimation methods, especially in those cases involving minors. However, when their country of origin is unknown, or it can be only roughly estimated, it is extremely difficult to apply assessment policies, procedures, and practices that are accurate and child-sensitive. The main aim of this research is to optimize the correct classification of adults and minors by establishing new cut-off values for four different continents (Africa, America, Asia, and Europe). For this purpose, a vast sample of 10,701 orthopantomographs (OPTs) from four continents was evaluated. For determination and subsequent validation of the new third molar maturity index (I3M) cut-off values by world regions, a cross-validation by holdout method was used and contingency tables (confusion matrices) were generated. The lower third molar maturity indexes, from both left and right side (I3ML and I3MR) and the combination of both sides (I3ML_I3MR) were calculated. The new cut-off values, that aim to differentiate between a minor and an adult, with more than 74.00% accuracy for all populations were as follows (I3ML; I3MR; I3ML_I3MR, respectively): Africa = (0.10; 0.10; 0.10), America = (0.10; 0.09; 0.09), Asia = (0.15; 0.17; 0.14), and Europe = (0.09; 0.09; 0.09). The higher sensitivity (Se) was detected for the I3ML for male African people (91%) and the higher specificity (Sp) of all the parameters (I3ML; I3MR; I3ML_I3MR) for Europeans both male and female (> 91%). The original cut-off value (0.08) is still useful, especially in discriminating individuals younger than 18 years old which is the goal of the forensic methods used for justice.

Effects of maxillary expansion and protraction on pharyngeal airway dimensions in relation to changes in head posture and hyoid position : A retrospective cohort study.

PURPOSE: To assess changes in pharyngeal airway dimensions, head posture and hyoid position after maxillary expansion and face mask (FM) treatment compared to untreated class III patients. METHODS: This study examined 24 class III patients (10 girls, 14 boys, mean age: 10.97 ± 0.88 years) treated with expansion and a petit-type FM appliance and 24 untreated class III patients (16 girls, 8 boys, mean age: 10.50 ± 1.06 years). Pre- and posttreatment cephalometric radiographs were digitally analysed. Parametric data were analysed with paired and independent-samples t­tests, nonparametric data were analysed with Wilcoxon signed-rank and Mann-Whitney U tests. Spearman's correlation analysis was used to examine the relationship between dental/skeletal treatment changes and those of craniocervical postural position, pharyngeal airway dimension and hyoid position. RESULTS: With respect to the hypopharyngeal airway dimension, the hypopharyngeal sagittal length (CV3'-LPW), velar angle (HRL/U-PNS) and velar length (U-PNS) significantly increased in the treatment group. All the parameters describing head posture and those describing the distances of the hyoid bone to the HRL changed significantly after treatment, but these changes were not significantly different from the control group. In the treatment group, there also occurred a significant increase in the sagittal growth of the maxilla (SNA, Co­A, Na-Perp A, Wits), vertical growth of the maxillomandibular complex (SN-GoGN, N­ANS, N­Me), counterclockwise rotation of the maxilla (SN-PP) and overjet, while a clockwise rotation (y-axis) and a nonsignificant inhibition of the sagittal growth (Co-Gn) of the mandible were observed. The treatment induced increases of hypopharyngeal sagittal length (CV3'-LPW), soft palate thickness and anteroposterior movement of hyoid bone (H-CV3) demonstrated a positive correlation with changes of craniocervical angles (NSL/OPT, NSL/CVT) and a negative correlation with craniohorizontal angles (OPT/HOR, CVT/HOR). The change of the anteroposterior movement of hyoid bone (H-CV3) was also positively correlated with oropharyngeal sagittal length (CV2'-MPW), the hypopharyngeal sagittal length (CV3'-LPW) and the minimal dimension of the pharyngeal airway space (PASmin). CONCLUSION: While expansion and FM treatment did not affect the head posture and hyoid bone position, positive effects were observed in the hypopharyngeal airway region.

Does childhood chemotherapy affect mandibular bone structures in a lifetime?

BACKGROUND: Chemotherapy, one of the most important treatment modalities for treating childhood cancers, is a major cause of bone loss in patients and survivors. OBJECTIVES: This study aimed to evaluate mandibular bone structures in childhood cancer survivors (CCSs) by means of fractal dimension (FD) analysis and the Klemetti index (KI), and to compare them with regard to the control group. MATERIAL AND METHODS: In this retrospective study, the panoramic radiographs of 49 CCSs were included as the study group and the panoramic radiographs of 49 cancer-free volunteers were included as the control group. Based on the panoramic radiographs, FD and KI were determined. RESULTS: No significant differences were observed between the study and control groups in terms of mean FD values for regions of interest (ROIs) ROI_1, ROI_2 and ROI_3 (p = 0.750, p = 0.490 and p = 0.910, respectively). The mean FD values for ROI_1 for the study and control groups were 1.08 ±0.18 and 1.07 ±0.14, respectively. The mean FD values for ROI_2 for the study and control groups were 1.11 ±0.13 and 1.09 ±0.13, respectively. The mean FD values for ROI_3 for the study and control groups were 1.15 ±0.14 and 1.15 ±0.15, respectively. Statistically significant differences between the study and control groups were noted only in the distribution of the KI categories (p = 0.015). CONCLUSIONS: Childhood chemotherapy may affect mandibular bone structures during a lifetime. The Klemetti index should be considered a useful clinical diagnostic tool for the examination of mandibular bone structures.

Peri-implant bone microstructural analysis and comparison of resonance frequency analysis before prosthetic placement: a retrospective study.

OBJECTIVES: Fractal analysis is a mathematical method used for the calculation of bone trabeculation and lacunarity. This study aims to evaluate the relationship between resonance frequency analysis (RFA) and fractal dimension (FD) of peri-implant bone to determine the preload stability of implants. MATERIALS AND METHODS: In this study, the results of the fractal analysis calculated from the resonance frequency analysis results taken in the 3rd month of the patients who underwent 2-stage implant by the same doctor and the radiographs taken in the same session were evaluated. A hundred implants in 20 patients were applied in this study. The implant stability quotient (ISQ) values of the implants and fractal dimension values of the peri-implant bone were calculated. RESULTS: The findings showed that the ISQ1 (p = 0.008), ISQ2 (p = 0.038), ROI2 (p = 0.013), and ROI3 (p < 0.001) values were statistically significantly higher in men than women. The ISQ1 (p = 0.003), ISQ2 (p = 0.013), ROI1 (p = 0.011), and ROI3 (p < 0.001) of the mandible were statistically higher than the maxilla. The fractal dimension cut-off value to assess prosthetic loading was found 1.198. CONCLUSION: Fractal analysis is a non-invasive method that can be used in conjunction with clinical examination in the prosthetic loading decision of implants. It is a valuable parameter that can be used without the need for an extra device when it is necessary to reduce the clinical study time. CLINICAL RELEVANCE: Calculating the fractal dimension of the peri-implant bone is a practical, economical, and applicable method for clinicians. FD calculated from panoramic radiographs used for diagnosis in routine treatments in clinics where access to the necessary devices for ISQ measurement is not available will contribute to clinical practice.

A deep learning approach to dental restoration classification from bitewing and periapical radiographs.

OBJECTIVE: The aim of this study was to examine the success of deep learning-based convolutional neural networks (CNN) in the detection and differentiation of amalgam, composite resin, and metal-ceramic restorations from bitewing and periapical radiographs. METHOD AND MATERIALS: Five hundred and fifty bitewing and periapical radiographs were used. Eighty percent of the images were used for training, and 20% were left for testing. Twenty percent of the images allocated for training were then used for validation during learning. The image classification model was based on the application of CNN. The model used Resnet34 architecture, which is pre-trained on the ImageNet dataset. Average sensitivity, receiver operating characteristic (ROC) curve, and area under the curve (AUC) were calculated for performance evaluation of the model. RESULTS: The model training loss was 0.13, and the validation loss was 0.63. The independent test group result was 0.67. Amalgam AUC was 0.95, composite AUC was 0.95, and metal-ceramic AUC was 1.00. The average AUC was 0.97. The false positive rate in the validation set was 18, the false negative rate was 18, the true positive rate was 60, and the true negative rate was 138. The true positive rate was 0.82 for amalgam, 0.75 for composite, and 0.73 for metal-ceramic. CONCLUSION: Deep learning-based CNNs from periapical and bitewing radiographs appear to be a promising technique for the detection and differentiation of restorations.

Evaluation of styloid chain calcification related to temporomandibular joint disc displacement: a retrospective cohort study.

OBJECTIVES: The present study aimed to evaluate any relationship between elongated styloid process (ESP) and temporomandibular joint disc displacement (TMJD). STUDY DESIGN: A retrospective cohort study. SETTING: Dentomaxillofacial Radiology division of Erciyes University Dental Hospital. PARTICIPANTS: Ninety-four temporomandibular joints (TMJs) of 47 patients were allocated in this study. Intervention-disease: Two experienced dentomaxillofacial radiologists have interpreted all CBCT and MR images. Patients who referred with TMJ disorders were classified according to temporomandibular joint's disc status as normal disc position (ND), displacement with reduction (DWR) and displacement without reduction (DWoR). METHODS: Main outcome measures: Interpretation of styloid chain calcification pattern and styloid processes length measured linearly on reconstructed sagittal slices of CBCT. Randomization: Cone beam computed tomography (CBCT) and magnetic resonance (MR) images of 154 patients who were admitted between September 1, 2012 and September 1, 2019. Only 47 of them fulfilled the study requirements. Blinding: Single blind of the outcome measurements and interpretations of MR images. RESULTS: Total 94 TMJs of 47 patients disc status groups were analyzed and defined as DWoR (n = 25), DWR (n = 32), and ND (n = 37). On multivariate analysis, no statistical significant differences were found between groups in terms of styloid process lengths. Mean SP length and standard deviation of disc status groups (DWoR, DWR, and ND) are 35.5 (± 9.8) mm, 34.6 (± 9.2) mm, and 38.3 (± 8.9) mm, respectively. When patients were grouped individually according to their post-MRI diagnosis, the mean styloid process length in the non-temporomandibular joint disc displacement (non-TMJD) patients (47.9 ± 10.8) was significantly higher than the TMJD patients (36.1 ± 9.3). In this study, there is no intervention to cause any harm or side effects. CONCLUSION: Our results indicate that styloid-stylohyoid syndrome may be misdiagnosed with temporomandibular joint disorder (TMD). TRIAL REGISTRATION: Clinical Trials NCT04280107.

Evaluation of the peri-implant bone trabecular microstructure changes in short implants with fractal analysis.

BACKGROUNDS: This study aimed to evaluate the microstructural changes in the peri-implant bone in patients with short implants in terms of implant survival status by using fractal analysis measurements. RESULTS: Dental panoramic radiographs (DPRs) of 67 patients were examined and included in this study. Fractal analysis and measurement of the crown-implant ratio were performed with ImageJ. The fractal analysis measurement was performed on the DPRs obtained at preoperative (FD0) and in the follow-up periods (after 2 ± 2 weeks (FD1), 2 months ± 2 weeks (FD2), 6 months ± 2 weeks (FD3), and 12 months + (FD4)). A p value < 0.05 was considered statistically significant. Power analyses were conducted for the test results that did not reject null hypothesis. A significant difference was found in the FD1 and FD2 values between the implant survival groups (p < 0.001 and p = 0.023, respectively). The mean FD1 and FD2 values of the success group were significantly higher than those of the failure group. CONCLUSIONS: Fractal analysis is a useful method to measure the trabecular microstructure of bone in non-standardized dental radiographs. The present study has a low power to reject the null hypothesis because of the low number of cases of implant failure. Therefore, further study with a large sample size is warranted. In clinical practice, the survival of implants may be predicted by analyzing fractal dimension of the surrounding trabecular bone of the implants.

The evaluation of the mandibular bone structure changes related to lactation with fractal analysis.

OBJECTIVES: Lactation-induced bone loss of lumbar spine, hip, femur and distal radius are well documented in the literature. The aim of this article is to investigate whether lactation affects the trabecular and cortical bone structure of human mandible. METHODS: 120 dental panoramic radiographs (DPR) of the lactating women who were breastfeeding for 3-6 months (study group) and 120 DPRs of the nulliparous women (control group) were evaluated. Regions of interest (ROI) were chosen from the geometric center of ramus, the geometric center of angulus and the cortical bone. ROIs were examined with fractal analysis method. Fractal dimension (FD) values of each ROI were compared with each other. In addition, the study group was divided into four subgroups according to age, and FD values were compared within the subgroups. RESULTS: The control and study groups were age-matched. FD values of mandibular ramus and angulus were significantly lower in the study group (p < 0.001, p < 0.001). There was no significant difference for FD values of cortical bone between the groups.(p = 1.49). There was no significant difference for FD values of ROIs between the age subgroups (p = 0.05, p = 0.94, p = 0.91). CONCLUSION: This is the first study to investigate the possible effect of lactation in human jaws. Trabecular rich sites of the mandible were found affected by lactation. Dentists who encounter with lactating patients must be careful during the dental processes such as tooth extraction, implant surgery, and orthodontic treatment.

Effect of internal derangements and degenerative bone changes on the minimum thickness of the roof of the glenoid fossa in temporomandibular joint.

OBJECTIVES: The aim of this study is to investigate the effect of internal derangements and degenerative bone changes on the minimum thickness of the roof of the glenoid fossa (RGF). METHODS: MRI and cone beam CT records of temporomandibular joints (TMJ) of 68 patients were evaluated retrospectively in this study. The joints were divided into three groups according to TMJ disc status which had been diagnosed in MRI: normal disc status, anterior disc displacement with reduction, and anterior disc displacement without reduction. Cone beam CT was used to evaluate the degenerative bone changes of TMJ and to measure the minimum thickness of RGF. The joints were categorized as "with osteoarthritis (OA)" or "without OA". The findings of OA were determined as erosion, osteophyte, flattening, sclerosis, and pseudocyst. RESULTS: No significant relationship was found between gender and the thickness of RGF (p > 0.05). RGF was found significantly higher in "with OA" group compared to "without OA" group (p < 0.001). No significant difference was found between disc displacement groups for minimum thickness of RGF (p > 0.005). No significant difference was found between condyles without erosion and condyles with erosion for the minimum thickness of RGF (p = 0.272). In the present study, osteophyte, sclerosis, flattening, and pseudocyst were found to be associated with the minimum thickness of RGF. CONCLUSIONS: Osteophyte, flattening, pseudocyst, and sclerosis have an influence on RGF thickness. The minimum thickness of RGF is not significantly correlated with internal derangements. Erosion is not significantly correlated with RGF thickness. RGF thickness may be unaffected by the early stages of OA.