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.

Does Le Fort I Osteotomy Influence Nasal Septum Deviation?

BACKGROUND: Le Fort I osteotomy is a technique for surgically correcting the maxillary position. Le Fort I osteotomy may affect the nasolabial structures since a very close relationship exists between the maxilla and the nose. PURPOSE: This study aimed to investigate the effect of different maxillary movements on the nasal septum after Le Fort I osteotomies with cone beam computed tomography (CBCT) images. We hypothesized that nasal septal angle changes after maxillary impaction and advancement movements. STUDY DESIGN, SETTING, AND SAMPLE: This retrospective cohort study involved patients who underwent Le Fort I osteotomy to correct the maxillary position at Erciyes University, Oral and Maxillofacial Surgery Hospital. This study included patients who had CBCT images before (T0) and ≥12 months after (T1) surgery. Patients with a history of septoplasty or rhinoplasty before orthognathic surgery, congenital deformities, or posttraumatic deformities were excluded. PREDICTOR VARIABLES: Its predictor variable was the direction and magnitude of the maxilla's vertical and horizontal movements. MAIN OUTCOME VARIABLE: Change in septal deviation (in degrees) was the main outcome of the study. COVARIATES: Age, sex, operation (Le Fort I alone or double jaw surgery), cartilage reduction, and anterior nasal spine reduction during surgery were covariates. DATA ANALYSIS: Angle values were compared with independent samples t test or the Mann-Whitney U test in two-category variables. The Kruskal Wallis test was used to compare the angle values according to the movement. A P value of < .05 was considered statistically significant. RESULTS: This study evaluated 154 CBCT images of 77 patients (44 [57.1%] females and 33 [42.9%] males), of which 68 (88.3%) had double jaw surgery and nine (11.7%) had single Le Fort I surgery. The average nasal septum angle was significantly smaller preoperatively (166.2° [157.1° to 172.15°]) than postoperatively (168.7° [131.5° to 180.0°]) across subjects (P = .031). The septal angle decreased in 28 patients, and the rate of postoperative angular change was higher in patients with both advancement and impaction during the surgery (P = .014). CONCLUSION AND RELEVANCE: Septum deviation can occur in 37% of cases after Le Fort I surgery. Therefore, Le Fort osteotomies are associated with changes in nasal appearance.

Developing deep learning methods for classification of teeth in dental panoramic radiography.

OBJECTIVES: We aimed to develop an artificial intelligence-based clinical dental decision-support system using deep-learning methods to reduce diagnostic interpretation error and time and increase the effectiveness of dental treatment and classification. STUDY DESIGN: We compared the performance of 2 deep-learning methods, Faster Regions With the Convolutional Neural Networks (R-CNN) and You Only Look Once V4 (YOLO-V4), for tooth classification in dental panoramic radiography to determine which is more successful in terms of accuracy, time, and detection ability. Using a method based on deep-learning models trained on a semantic segmentation task, we analyzed 1200 panoramic radiographs selected retrospectively. In the classification process, our model identified 36 classes, including 32 teeth and 4 impacted teeth. RESULTS: The YOLO-V4 method achieved a mean 99.90% precision, 99.18% recall, and 99.54% F1 score. The Faster R-CNN method achieved a mean 93.67% precision, 90.79% recall, and 92.21% F1 score. Experimental evaluations showed that the YOLO-V4 method outperformed the Faster R-CNN method in terms of accuracy of predicted teeth in the tooth classification process, speed of tooth classification, and ability to detect impacted and erupted third molars. CONCLUSIONS: The YOLO-V4 method outperforms the Faster R-CNN method in terms of accuracy of tooth prediction, speed of detection, and ability to detect impacted third molars and erupted third molars. The proposed deep learning based methods can assist dentists in clinical decision making, save time, and reduce the negative effects of stress and fatigue in daily practice.

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 orofacial applications of low-magnitude, high-frequency mechanical vibration on cranial sutures and calvarial bones: A micro-computed tomography study in rats.

INTRODUCTION: The purpose of this study was to assess the effects of orthodontically aimed low-magnitude, high-frequency mechanical vibration (OLMHFMV) on intact calvarial bone, specifically the parietal and temporal, and cranial sutures, including the sagittal and parietotemporal, of rats in differing stages of growth and development. METHODS: Forty Wistar rats were divided into 4 groups: 2 control groups and 2 OLMHFMV groups. Subsequently, 0.3 cN of force with a frequency of 30 Hz was applied as OLMHFMV on the temporomandibular joint region in the rats in the OLMHFMV-1 group, with the protocol of 20 min/d for 5 d/wk for 1 month, whereas the rats in the OLMHFMV-2 group received mechanical stimuli for 2 months with the same protocol. Morphometric and structural analyses, including suture width, cranial width and height, bone mineral density, bone volume/tissue volume, trabecular number, trabecular separation, and trabecular thickness analyses, were carried out using micro-computed tomography. RESULTS: The width of the parietotemporal and sagittal sutures and the cranial height and width increased significantly by OLMHFMV (P <0.021). The structural analysis revealed that trabecular number and trabecular separation increased, whereas trabecular thickness decreased in the OLMHFMV groups compared with the control groups (P <0.048). Bone volume/tissue volume remained unchanged despite reducing the bone mineral density of the OLMHFMV groups. CONCLUSIONS: OLMHFMV had a potential for modulating sutural and cranial growth in adolescent rats. OLMHFMV increased the structural quality of the temporal and parietal bones. These effects may have clinical implications as a treatment option for patients suffering from craniofacial anomalies such as craniosynostosis or a supportive approach for dentofacial orthodontic treatments.

How much should incisors be decompensated? periodontal bone defects during presurgical orthodontic treatment in class III double-jaw orthognathic surgery patients.

INTRODUCTION: The aims of this study were to evaluate periodontal bone defects around the lower and upper incisors and to identify changes in the buccolingual inclination of the incisors during orthodontic decompensation in skeletal Class III orthognathic surgery patients. MATERIALS AND METHODS: The sample consisted of 26 adults with skeletal Class III deformity who had undergone presurgical orthodontic treatment and orthognathic surgery. Lateral cephalograms obtained before orthodontic treatment and before surgery were used to determine the inclination and position changes of the incisors. Cephalometric measurements were taken using Dolphin Imaging 11.95. Three-dimensional images were generated from cone-beam computed tomography (CBCT) scans prior to surgery and used to detect periodontal bone defects, including fenestration (F) and dehiscence (D). RESULTS: Intraclass correlation coefficients (ICC) were determined and the measurements showed high reproducibility. The cephalometric data showed normal distribution and there were no differences between genders in terms of cephalometric changes, dehiscence, fenestration, or coexistent (D-F/DF) formation. The patients presented maxillary incisor retroclination and mandibular incisor proclination, which was consistent with the tooth decompensation. CBCT assessment was performed for a total of 208 teeth; while 81 upper and 94 lower incisors had D-F/DF formation, 23 upper and 10 lower incisors were healthy. Statistically significant correlations were not found between the inclination degree of the incisors and D-F/DF formation. CONCLUSIONS: Decompensation of incisors during presurgical orthodontic treatment increases the risk of periodontal defects. There is no linear relationship between the increase in the inclination degrees of incisors and D-F/DF formation.

Evaluation of mandibular bone changes in multiple myeloma patients on dental panoramic radiographs.

OBJECTIVE: The aim of this study is to assess the mandibular bone structures of multiple myeloma (MM) patients on panoramic radiographs using fractal analysis (FA) and radio-morphometric indices. METHODS: The study group consisted of 67 MM patients, and the control group consisted of 67 individuals without any systemic disease. The mandibular cortical index (MCI) classification, antegonial index (AGI), gonial index (GI), mandibular cortical width (MCW), panoramic mandibular index (PMI) and fractal dimensions (FD) were evaluated on panoramic radiographs. FD measurements were made by identifying 4 related areas. Shapiro-Wilk test was used to determine the normal distribution of the data. Chi-square and independent t tests were used to compare the findings between the two groups. RESULTS: The FD values of the study group in ROI1, ROI2, ROI3, ROI4 regions and GI values were found to be statistically significantly lower than the control group (p < 0.001). There was no statistically significant difference between the two groups in terms of AGI, MCW and PMI values (p > 0.05). While C1 was the most common type in the control group, C2 was the most common type in the study group. C2 and C3 were detected more in the study group than in the control group (p < 0.001). CONCLUSION: Our study showed a consensus with the studies advocating that fractal analysis and radio-morphometric indices are methods that can be used to determine mandibular bone density. The low bone density of MM patients is a condition that physicians should be aware of for interventional dental procedures.

Evaluation of mandibular trabecular bone by fractal analysis on panoramic radiograph in paediatric patients with sleep bruxism.

OBJECTIVE: To evaluate the trabecular bone density in the mandible of paediatric patients diagnosed with sleep bruxism (SB) using the fractal analysis method on panoramic radiographs. METHODS: A total of 37 patients whose anamnesis and clinical signs were compatible with SB were diagnosed with SB using BiteStrip® . Three areas were identified on the panoramic radiographs of the patients: the geometric center of the condyle, the angulus region under the mandibular canal, and the distal region of the mental foramen. Regions of interest (ROIs) of 60 × 60 pixels were selected in these three locations, and fractal dimensions (FDs) were calculated. Results were compared with the control group. RESULTS: There was no statistically significant difference between the right and left FD values, and male and female FD values in all regions and both groups (p > .05). In the angulus (p = .03) and condyle (p = .03) regions, the SB group had a significantly higher FD value than the control group. There was no statistically significant difference between the SB and control groups in the corpus region (p = .98). A moderate negative correlation arose between age and condyle FD values among controls (r = -0.38, p = .02). CONCLUSION: Fractal dimension values evaluating trabeculation of the mandibular bone are affected by SB in the angulus and condyle regions.

Evaluation of trabecular bone healing using fractal dimension analysis after augmentation of alveolar crests with autogenous bone grafts: a preliminary study.

OBJECTIVE: The aim of this study is to evaluate bone remodeling after alveolar crest augmentation with autogenous bone grafts. METHODS: 50 patients who were applied augmentation due to alveolar deficiency were included in this study. Fractal dimensions were measured on the radiographs in the preoperative, postoperative, follow-up periods. The ROI was selected specific to each patient, but repeated in a standardized manner on subsequent radiographs. RESULTS: A total of 50 patients were included in the study; There were 31 females and 19 males. Implants were placed in all patients without any complications. The mean fractal dimensions on the graft recipient side were statistically higher in the postoperative 5th month compared to the postoperative 1st week (p = 0.002). The mean fractal dimensions on the donor side were statistically higher in the preoperative and postoperative 5th month compared to the postoperative 1st week (p < 0.001). CONCLUSION: Any clinical imaging method cannot fully reflect the histological microstructures of the bone. Evaluating the fractal analysis together with the clinical results can demonstrate adequate bone healing and quality prior to implant placement. Fractal analysis is a non-invasive, reproducible, method but further, prospective, randomized, controlled clinical studies are needed to estimate bone quality prior to implant placement.

Treatment and posttreatment effects of Herbst appliance therapy on trabecular structure of the mandible using fractal dimension analysis.

OBJECTIVES: This controlled study aimed to evaluate the effects of Herbst therapy on the trabecular structure of the condyle and angulus mandible using fractal dimension analysis (FD-A) accompanied by skeletal cephalometric changes. MATERIAL AND METHOD: The panoramic and cephalometric radiographs of 30 patients with skeletal Class II malocclusion treated with the Herbst appliance (C II-H group, mean age: 15.23 ± 1.08), 30 patients with skeletal Class II malocclusion that received fixed orthodontic treatment (C II-C group, mean age: 15.73 ± 1.38), and 30 patients with skeletal Class I malocclusion (C I-C group, mean age: 15.90 ± 1.30) were selected. FD-A was performed on the superoposterior region (C-SP) and centre of the condyles (C-C) and the mandibular angulus (Ang) on the panoramic radiographs taken at the pretreatment (T0), intermediate stage of treatment (T1), and posttreatment (T2) timepoints just like cephalometric analysis. RESULTS: Herbst therapy provided a statistically significant increase in SNB, ANS-Me, Na-Me, S-Go, Co-Gn and a decrease in ANB and overjet (P < 0.05). All skeletal changes remained stable during the fixed appliance treatment after Herbst. The FD values in C-C increased (P < 0.05), and C-SP values decreased (P < 0.05) during Herbst therapy, while after removal of the Herbst appliance, no significant change was observed despite an increase in C-SP. The Ang value did not change during Herbst treatment, but then increased significantly (P < 0.05). There was no significant change in the FD values of the C I-C and C II-C groups at any stage of treatment. The C-C and C-SP changes at T1-T0 period, C-SP and Ang changes at T2-T1 period, and C-C, C-SP, and Ang values at T2-T0 period were found higher in C II-H group compared with the C II-C group significantly (P < 0.05). CONCLUSION: Herbst therapy changed the trabecular structure of the condyles in different directions at the superoposterior and central regions of the condyles, while the structural complexity of the angulus mandible, which did not change during the Herbst treatment, increased during the fixed orthodontic treatment after Herbst.

Radiographic changes in the temporomandibular joint related to medication in rheumatic diseases.

OBJECTIVES: The purpose of this study was to assess radiographical changes on temporomandibular joint (TMJ) in relation the autoimmune rheumatic diseases and the medicines that treat this diseases with cone beam computed tomography(CBCT). METHODS: 65 people with rheumatoid diseases were included in the study and divided into five subgroups according to drugs they used. Condyle height (CH), anteroposterior dimension (APD), mesiolateral dimension (MLD) and superior joint space (SJS) were measured in order to evaluate mandibular condyle dimensions. Further, were evaluated in terms of osteoarthritic changes such as erosion, flattening, osteophyte and subchondral cyst in the mandibular condyle. TMJ measurements were compared between study-control groups and subgroups by using Student's t-test, Mann-Whitney-U test, one-way analysis of variance (ANOVA) and Kruskal-Wallis test. The association between osteoarthritic features, rheumatoid status was tested by using χ2 test. Observers were blinded to all groups. Cohen κ values (0853-0945) and Spearman's correlation coefficient (0.959-0.997) indicated high interexaminer reliability. RESULTS: Condylar dimentions were significantly lower in CH and SJS in rheumatic diseases group (p < 0.001), however APD (p = 0,681) and MLD (p = 0,757) was not different significantly. Osteoarthritic changes such as erosion (p < 0.001), flattening (p = 0.005), osteophyte (p = 0.001) and subchondral cyst (p = 0.001) were significantly higher in the patient group. None of the parameters were different significantly according to subgroups determined according to drugs used(p > 0.05). CONCLUSIONS: Degenerative changes may cause decrease in condyle size and changes in condyle position. It is a process that can continue despite the use of antirheumatic or immunosuppressive drugs. All of these can become the source of possible TMJ problems.

Effects of root-cortex relationship, root shape, and impaction side on treatment duration and root resorption of impacted canines.

OBJECTIVES: This retrospective longitudinal study aimed to evaluate the factors that affect the orthodontic treatment duration (OTD) and external apical root resorption (EARR) of maxillary impacted canines (MIC) as root-cortex relationship, root shape, impaction side, and gender. MATERIAL AND METHOD: Thirty-eight patients (mean age 15.28 ± 1.48 years) who had unilateral MIC and undergone orthodontic treatment were included in this study. Root-cortex relationship, root-cortex intersection amount, root shape, impaction side, height, alpha angle, impaction zone, and length of the MIC were evaluated on cone-beam computed tomography images at the beginning of the treatment. Final assessments were performed on ortopantograms at the end of the treatment as canine angulation and tooth length. The sample was characterized by descriptive statistics; t-tests, Mann-Whitney U-test, ANOVA, and Kruskal-Wallis tests were used for the comparison of EARR and OTD values between the categorical groups. RESULTS: Root shape affected OTD, and the longest value was detected in MIC with bent root (P < 0.000). The presence of root-cortex relationship also prolonged OTD for approximately 3 months (P = 0.006). MIC with risk factors like positive root-cortex relationship and bent roots had higher EARR values than those with negative root-cortex relationship and normal roots (P = 0.042, P = 0.021, respectively). EARR of the palatal MIC was also higher than the buccal MIC (P = 0.009). OTD was significantly influenced by root-cortex intersection amount (P = 0.004). CONCLUSION: The presence of root-cortex relationship and abnormal root shape were risk factors for greater EARR of MIC along OTD, which was also significantly influenced by root shape and root-cortex relationship.

Investigation of the effectiveness of CBCT and gray scale values in the differential diagnosis of apical cysts and granulomas.

PURPOSE: The aim of this study was to investigate the effectiveness of cone-beam CT (CBCT) findings and gray scale values (GSV) in the differential diagnosis of apical cysts and granulomas. METHODS: Two independent researchers retrospectively analyzed the CBCT images of 21 teeth and histopathologically diagnosed them as having radicular cysts or apical granulomas. In the CBCT images, apical lesions were evaluated and categorized according to 7 criteria. These criteria were determined as relationship of lesions with dental roots, periphery of the lesion, shape, darker focus in the center, root resorption, displacement in related teeth, and cortical bone perforation. In addition, the minimum and maximum gray scale values of the lesions were measured and compared. RESULTS: There was a statistically significant relationship between histopathological (HP) diagnosis and well-defined cortical border and lesion shape (p = 0.003, p = 0.014, respectively). According to the HP diagnosis, no statistically significant difference was found among other variables (p > 0.05) CONCLUSION: The presence of a well-defined cortical border or partial cortical border is a distinctive criterion for cysts. Additionally, the shape of the lesion was found to be a significant criterion for the separation of the two lesions. The shape of cystic lesions was circular and apical granulomas had a more curved shape. There was no relationship between the histopathological diagnosis of lesions and CBCT gray scale values.

Effects of mesenchymal stem cell transfer on orthodontically induced root resorption and orthodontic tooth movement during orthodontic arch expansion protocols: an experimental study in rats.

OBJECTIVES: The aim was to evaluate the effects of mesenchymal stem cell (MSC) transfer to periodontal ligament (PDL) on the inhibition and/or repair of orthodontically induced root resorption (OIRR) during and after arch expansion and on the orthodontic tooth movement (OTM) rate of the maxillary first molar teeth of rats. MATERIAL AND METHODS: Sixty Wistar rats were divided into three groups as the untreated group, MSC and control injections during the expansion period group (EMSC-EC), and MSC and control injections at the retention period group (RMSC-RC). Fifty grams of orthodontic force was applied to the maxillary first molar teeth of the rats for 14 days in the vestibular direction, and then, 20 days of retention was carried out. MSCs and control injections were performed every 3 days in the EC, RC, EMSC, and RMSC groups. At the end of the experiment, samples were prepared for OTM evaluation, mRNA expression analysis, micro-computed tomography measurements, cementum thickness calculations, and structural examinations. RESULTS: The amount of OTM in EMSC group was significantly higher than in EC group (P < 0.001). MSC transfer during the expansion and retention periods reduced the number of resorption lacunae, volumetric and linear resorptive measurements, and cyclooxygenase-2 and receptor activator of nuclear factor kappa B ligand (RANKL) mRNA expression levels, and increased the osteoprotegerin (OPG) expression levels, OPG/RANKL ratio, and cementum thickness in the EMSC and RMSC groups. CONCLUSIONS: MSC transfer to PDL during expansion increased the amount of OTM. Injection of MSC during the retention period was found to be slightly more effective in prevention and/or repair of OIRR than MSC transfer during the expansion period.

Role of cone-beam computed tomography in the evaluation of a paradental cyst related to the fusion of a wisdom tooth with a paramolar: A rare case report.

Fusion is an abnormality of tooth development defined as the union of two developing dental germs, resulting in a single large dental structure. This irregular tooth morphology is associated with a high predisposition to dental caries and periodontal diseases. As a result of recurring inflammatory periodontal processes, disorders such as periodontal pocket, pericoronitis, and paradental cysts may develop. A rare mandibular anatomic variation is the retromolar canal, which is very significant for surgical procedures. The fusion of a paramolar and mandibular third molar associated with a paradental cyst co-occurring with the presence of a retromolar canal is rare, and the aim of the present study is to describe the evaluation of this anatomical configuration using cone-beam computed tomography.

Prevalence and Morphologic Characteristics of Ponticulus Posticus: Analysis Using Cone-Beam Computed Tomography.

OBJECTIVE: This study evaluated the prevalence and morphologic characteristics of ponticulus posticus (PP) by using cervical 3-dimensional (3-D) cone-beam computed tomography (CBCT) scan images. METHODS: This was a retrospective study conducted by selecting cervical 3-D CBCT images of 698 patients, which were examined for the presence and types of PP. RESULTS: In 257 patients, 438 PPs, complete or partial, bilateral or unilateral, were identified on the 698 cervical 3-D CBCT scans; therefore, the prevalence was 36.8%. Bilateral complete PP and partial PP were observed in 6.3% and 16.2% of subjects, respectively. There was a significant difference in the prevalence between males and females (P = .001) and between the right and left sides between males and females, but not between age groups. CONCLUSION: Ponticulus posticus is a relatively common anomaly in this Turkish sample, which may have implications for those who perform clinical procedures on the upper cervical spine.