Cone Beam Computed Tomography Examinations Research Articles

An Attached Odontoma to the Roots of a Mandibular Molar Tooth: A Case Report

Introduction: Odontomas are the most common odontogenic tumors. These lesions are usually considered a hamartoma than a neoplasm. Unlike normal tooth morphology, tissue arrangement is irregular in these lesions. Odontoma has self-limiting and slow growth, and if left untreated, its size will not increase over time. Most of these lesions are clinically asymptomatic and are detected on routine radiographs prepared for other purposes. Odontomas usually are located pericoronally and cause tooth eruption disorders such as the lack of permanent teeth or retention of deciduous teeth. In some cases, an odontoma can cause swelling and expansion of the jaw. The purpose of the current report is presenting an unusual complex odontoma in a 10-year-old boy, which was closely related to the roots of tooth #30. Odontomas are usually located pericoronally and near the roots of adjacent teeth, separated by a septum of bone. There are a few reported cases such as the current case, with fusion to the tooth structure. There was slight intraoral swelling and tenderness in the affected region. Unlike most reported cases, tooth eruption disturbance was not observed. Extreme proximity of odontoma and the roots of tooth were detected in Cone-beam Computed Tomography examination. Separative bone septum and the sharp outline of the tooth roots did not detected. The lesion and the related tooth were removed by surgical treatment, and the patient was followed for 2 years.

RADICULAR GROOVE OF MAXILLARY PREMOLAR: IS A “DANGER ZONE"?

Objectives: To evaluate the presence of radicular groove and dentin thickness on the palatal aspect of the buccal root of maxillary first premolars using cone-beam computed tomography (CBCT). Materials and methods: Images of 312 maxillary first premolars belonging to 187 patients (between 18-69 years, 94 females and 93 males) who were referred to the clinic were retrospectively reviewed. Root canal treatment, periapical lesion, and post-core were excluded. One and three-rooted premolars were also excluded. CBCT images were viewed on the axial plane to detect grooves. The concave area on the palatal aspect of the buccal root was recorded as a groove. Buccal and palatal dentin thicknesses were measured by two observers at the level of 3 mm below furcation. Statistical analyses were performed. Results: Buccal and palatal thicknesses were 1.28(±0.25) and 0.87(±0.13) mm, respectively. According to Student’s t-test, buccal dentin thickness was statistically higher than palatal dentin (p=0.016). The prevalence of groove was 82.05%. While palatal thickness without groove was 0.93(±0.14) mm, palatal thickness corresponding to groove was 0.82(±0.12) mm. One-way ANOVA showed palatal and buccal thickness in group 1 (18-35 years) was statistically lower than group 3 (>65 years) (p=0.012 and p=0.003). No statistical difference in thickness was observed between sex and left or right side (p>0.05). Conclusions: Palatal thickness related to groove can be considered a “danger zone” for post-core and endodontic treatment. Considering the high prevalence (82.05%) and thin dentin of the groove, more conservative canal and post space preparation and CBCT examination are recommended to avoid perforation.

An analysis of patient dose received during cone-beam computed tomography in relation to scan settings and imaging indications as seen in a dental institution in order to establish institutional diagnostic reference levels.

To investigate the dose-area product (DAP) of cone-beam computed tomography (CBCT) examinations for different scan settings and imaging indications, and to establish institutional diagnostic reference levels (DRLs) for dose optimisation. A retrospective analysis of the DAP values of 3568 CBCT examinations taken from two different devices at the Prince Philip Dental Hospital, Hong Kong between 2016 and 2021 was performed. Patient- (age, gender, and imaging indication) and imaging-related (CBCT device, field-of-view (FOV), and voxel size) were correlated with the DAPs. The indication-oriented third-quartile DAP values were compared with DRLs from the UK, Finland, and Switzerland. The obtained third-quartile DAPs lower than the national DRLs and those for which no national DRLs have been proposed were used to establish institutional DRLs. In the investigated CBCTs, the DAP value for large FOV scans was significantly lower than medium/small FOVs. CBCTs with a small voxel size exhibited a significantly higher DAP than those with a medium/large voxel size. CBCTs for endodontic, periodontal, orthodontic, or orthognathic evaluation exhibited a significantly higher DAP than other indications. Twelve indication-oriented institutional DRLs were established and five of them were lower than the national DRLs: third molars (229 mGy×cm2), jaw cysts/tumours (410 mGy×cm2), maxillary sinus pathology (520 mGy×cm2), developing dentition (164 mGy×cm2), and periapical lesions (564 mGy×cm2). CBCT examinations for endodontic, periodontal, orthodontic, or orthognathic evaluation may deliver a higher radiation dose to the patient than other imaging tasks. A periodic review of the patient dose from CBCT imaging and establishment of institutional DRLs for specific clinical settings are needed for monitoring patient dose and to optimise indication-oriented scanning protocols.

Impact of thyroid gland shielding on radiation doses in dental cone beam computed tomography with small and medium fields of view

The purpose of this study was to evaluate the impact of thyroid gland shielding on radiation doses in dental cone beam computed tomography (CBCT) with small and medium fields of view (FOVs). Six CBCT protocols were investigated by exposing an adult anthropomorphic male phantom head without and with thyroid shielding, using 4 small (4×5 cm) and 2 medium (10×6 cm) FOVs. Twenty metal oxide semiconductor field-effect transistor dosimeters were placed in the phantom head to measure absorbed doses and calculate equivalent doses at 11 sites. Effective doses were calculated based on the tissue weighting factors in International Commission on Radiological Protection Publication 103. The data were analyzed using the independent samples t test. Thyroid gland shielding led to significant equivalent dose reductions in many tissues for all protocols. Equivalent dose reductions to the thyroid were significant in all 6 protocols (P ≤ .037). Significant reduction depended on the FOV and ranged between 24.5% and 42.6% for the thyroid gland and 4.9% and 34.5% for other tissues and organs. Effective doses were significantly lower in all protocols (P ≤ .016). Thyroid gland shielding protects the thyroid gland and other organs and should be utilized with all CBCT examinations where feasible.

Feasibility analysis of immediate implant placement in the maxillary molar region

Objective: To study the clinical outcomes and feasibility of immediate implantation after flap surgery and minimally invasive extraction in the maxillary molar area and to provide a reference for it. Methods: Forty-one patients (41 molars in total) with maxillary molars that could not be preserved, treated from June 2018 to June 2020 at the Department of Oral and Maxillofacial Surgery at the Affiliated Hospital of Qingdao University, were selected. There are 24 males and 17 females with the age of (49.7±1.8) years (range 18-66 years). Pre-operative cone-beam CT (CBCT) was taken for measurement and analysis. After flap surgery and minimally invasive tooth extraction, the inflammatory granulation tissues attached to the soft and hard tissues were completely scraped and clipped, followed by the preparation of the implants in the correct three-dimensional position. Torque value and implant stability quotient (ISQ) were recorded after implant placement and with non-submerged healing. CBCT examination was taken 6 months after surgery and ISQ value was checked before crown restoration. CBCT examination was also taken 1 year after the permanent restoration. The survival rate of 6 months after surgery, the success rate of 1 year after permanent restoration, and the size of jump gaps immediately after surgery, 6 months after surgery, 1 year after permanent restoration respectively, were performed. The ISQ values were compared immediately and 6 months after surgery. Results: A total of 41 implants were placed in 41 patients. Six months after surgery, the survival rate was 100% (41/41). Twelve months after permanent restoration, the success rate of the implant restoration was 100% (41/41). The torque value after implant implantation was (42.77±0.79) N·cm. The buccal and palatal jump gaps were (3.15±0.16) mm and (2.86±0.18) mm immediately after surgery, respectively. The mesial and distal jump gaps were (2.94±0.19) mm and (3.77±0.21) mm, respectively. CBCT showed that no jump gap around the implants at 6 months after surgery and 1 year after permanent restoration. The ISQ values at immediately and 6 months after surgery were (74.78±0.59) and (80.20±0.49) respectively, and the difference was statistically significant (t=-9.03, P<0.001). Conclusions: Immediate dental implantation in the correct three-dimensional position could achieve good osseointegration by means of flap surgery, minimally invasive extraction and thorough removal of inflammatory tissue on the surface of soft and hard tissues. The clinical outcomes were satisfactory.

Entrance Surface Dose Measurement at Thyroid and Parotid Gland Regions in Cone-Beam Computed Tomography and Panoramic Radiography

Purpose: Ionizing radiation-absorbed doses is a crucial concern in Cone-Beam Computed Tomography (CBCT) and panoramic radiography. This study aimed to evaluate and compare the Entrance Skin Doses (ESD) of thyroid and parotid gland regions in CBCT and panoramic radiography in Yazd province, Iran.&#x0D; Materials and Methods: In this cross-sectional study, 332 patients were included, who were then divided into two age groups (adult and pediatric) and underwent dental CBCT and panoramic radiography. Twelve Thermoluminescence Dosimeters (TLD- GR200) were used for each patient to measure the ESD of thyroid and parotid glands. The differences between the ESD values in CBCT and panoramic examinations as well as between the adults and children groups were evaluated by one-way ANOVA and Man-Whitney tests.&#x0D; Results: The mean and Standard Deviation (SD) values of ESD in panoramic imaging were equal to 61 ± 4 and 290 ± 12 µGy for the thyroid and parotid glands of the adult groups, respectively. Notably, these values for CBCT were significantly higher (P&lt;0.01), as 377 ± 139 and 1554 ± 177 µGy, respectively. Moreover, the mean ESD values in the panoramic examination were 41 ± 3 and 190 ± 16 µGy for thyroid and parotid glands for the children group, while they were 350 ± 120 and 990 ± 107 µGy in CBCT (P&lt;0.01), respectively. The ESD values in the parotid gland were approximately 3.4 (2.8-4.1) and 4.7 (4.6-4.8) times greater than those for CBCT and panoramic examinations, respectively.&#x0D; Conclusion: Although CBCT provides supplementary diagnostic advantages, the thyroid and parotid glands’ doses are higher than panoramic radiography. Therefore, the risks and benefits of each method should be considered before their prescription.

Oral administration of inorganic nitrate alleviated biological damage induced by cone-beam computed tomography examination in Wistar rats

ObjectivesTo explore whether the inorganic nitrate has a protective effect on biological damage induced by cone-beam computed tomography (CBCT) and compare it with Vitamin C. Materials and methodsSixty Wistar rats were randomly separated into 6 groups: control group, irradiation (IR) group, NaNO3 group, IR + NaNO3 group, Vitamin C group, and IR + Vitamin C group. Rats were whole-body irradiated with CBCT four times. The absorbed dose of the skin surface was measured using thermoluminescent dosemeter chips and the mean whole-body absorbed dose was calculated. Peripheral blood was collected at 0.5 h and 24 h after irradiation. Bodyweight and organ index of rats before and after irradiation were analyzed. The bone marrow was taken for micronucleus test. Lymphocytes were isolated from peripheral blood for γ-H2AX immunofluorescence assay, apoptosis and reactive oxygen species (ROS) analysis. Total antioxidant capacity (TAC), malondialdehyde (MDA) and superoxide dismutase (SOD) in serum were detected. ResultsThe mean absorbed dose of four whole-body CBCT scans for rats was 73.04 mGy. Bodyweight and organ index before and after irradiation with X-ray had no significant differences. The micronuclei frequency of IR + NaNO3 and IR + Vitamin C groups showed a significant decrease than that in the IR group, which was not significantly different from that of the control group. The γ-H2AX foci rates in the IR + NaNO3 group and the IR + Vitamin C group were significantly lower than that in the IR group. In addition, the foci rate of the IR + NaNO3 group returned to the baseline level of the control group 24 h after CBCT scanning. The apoptosis of lymphocytes in rats did not increase. The IR + NaNO3 group (P < 0.001) or IR + Vitamin C group (P < 0.001) showed a significant increase in ROS positive cells rate with the control group, while were significantly lower than those in the IR group (P < 0.01). In addition, the ROS-positive cell rate in the IR + NaNO3 group was significantly lower than that in the IR + Vitamin C group. The MDA in the serum of rats increased significantly, while SOD and TAC decreased significantly at 0.5 h after irradiation. ConclusionsCompared with Vitamin C, inorganic nitrate had better preventive effects on biological damage induced by CBCT scans in rats.

Value of cone beam computed tomography for detecting bone invasion in squamous cell carcinoma of the maxilla

To determine the diagnostic value of cone beam computed tomography (CBCT) in detecting bone invasion in maxillary squamous cell carcinoma (MSCC). In this retrospective cohort study, preoperative CBCT scans were independently assessed by a single surgeon in imaging assessment 1 (IA 1) and by 1 surgeon with 2 dentists in consensus (IA 2) for the presence of bone invasion in MSCC. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, area under the receiver operating characteristic curve (AUC), and Cohen's κ were calculated. Histopathologic results of resection specimens served as the reference standard. Of 27 patients, 19 (70%) had proven bone invasion. IA 1 yielded 68.4% sensitivity, 75.0% specificity, 86.7% PPV, 50.0% NPV, 70.4% accuracy, and 0.717 AUC. All results of IA 2 were true-positive and true-negative, resulting in 100% sensitivity, specificity, PPV, NPV, accuracy, and AUC. The assessments differed in 6 cases. Interobserver κ was fair (0.38, 95% CI 0.04-0.72, P=.038). There was a significant association between CBCT detection of bone invasion and extent of surgical treatment (P=.006) CONCLUSIONS: The diagnostic accuracy of CBCT was high but observer-dependent. CBCT examination may be useful in surgical treatment planning.

Cone-Beam Computed Tomography Image Features under Intelligent Three-Dimensional Reconstruction Algorithm in the Evaluation of Intraoperative and Postoperative Curative Effect of Dental Pulp Disease Using Root Canal Therapy

Objective. The objective of this study was to analyze the application effect of algorithm-based three-dimensional reconstruction of cone-beam computed tomography (CBCT) images in the treatment of dental pulp disease (DPD) and the evaluation of the curative effect after treatment. Methods. 120 patients with DPD in hospital were selected as the research objects. In this study, based on the regridding model in the algorithm, the mapping relationship between the undersampled CBCT image and the fully sampled CBCT image was connected, and a model that can be used for image restoration and reconstruction was obtained after training. The algorithm model was used to reconstruct and repair the CBCT images of the research objects, and then, the reconstructed CBCT images were segmented based on the improved level set algorithm. After that, it analyzed and compared the accuracy of X-ray and CBCT based on three-dimensional reconstruction for the diagnosis accuracy of DPD and compared the average bone density of patients and the effect of root canal filling in each time period after root canal treatment. Result. After the image was reconstructed with the regridding model, a CBCT image of the patient’s teeth with less noise and clearer structure was obtained. The segmentation accuracy of the level set algorithm reached 85.5% on average, and the undersegmentation rate (UR) and the over-segmentation rate (OR) were both less than 6%. The diagnostic rates of X-ray and three-dimensional CBCT examination of DPD were 43.7% and 100%, respectively, and the difference was statistically significant ( P &lt; 0.05 ). Under the monitoring of the three-dimensional reconstruction of CBCT technology, the average bone density of the test group patients after 12 months of root canal treatment was the same as that of healthy people. Under X-ray examination, the average bone density of the test group patients was still lower than that of healthy people after 12 months of root canal treatment. Under the three-dimensional reconstruction of CBCT, the underfilling rate of patients after root canal treatment was 5%, the proper filling rate was 85%, and the overfilling rate was 10%. Conclusion. In summary, the CBCT reconstructed by the intelligent three-dimensional algorithm was effectively improved, which enhanced the image quality and segmentation efficiency. Analysis on diagnosis efficiency and treatment effect proved that CBCT can be an effective method to evaluate the initial curative effect of DPD treatment during and after the surgery and can provide valuable information in future dental treatment, thereby enhancing the success rate of DPD using root canal therapy.

Development of a deep learning model for automatic localization of radiographic markers of proposed dental implant site locations

ObjectivesTo develop a Deep Learning Artificial Intelligence (AI) model that automatically localizes the position of radiographic stent gutta percha (GP) markers in cone beam computed tomography (CBCT) images to identify proposed implant sites within the images, and to test the performance of the newly developed AI model. Materials and MethodsThirty-four CBCT datasets were used for initial model training, validation and testing. The CBCT datasets were those of patients who had a CBCT examination performed wearing a radiographic stent for implant treatment planning. The datasets were exported in Digital Imaging and Communications in Medicine (DICOM), then imported into the software Horos ®. Each GP marker was manually labelled for object detection and recognition by the deep learning model by drawing rectangles around the GP markers in all axial images, then the labelled images were split into training, validation, and test sets. The axial sections of 30 CBCT datasets were randomly divided into training and validation sets. four CBCT datasets were used for testing the performance of the deep learning model. Descriptive statistics were calculated for the number of GP markers present, number of correct and incorrect identifications of GP markers. ResultThe AI model had an 83% true positive rate for identification of the GP markers. Of the areas labelled by the AI model as GP markers, 28 % were not truly GP markers, but the overall false positive rate was 2.8 %. ConclusionAn AI model for localization of GP markers in CBCT images was able to identify most of the GP markers, but 2.8% of the results were false positive and 17% were missed GP markers. Using only axial images for training an AI program is not enough to give an accurate AI model performance.

Evaluating the Relationship between Mandibular Third Molar and Mandibular Canal with Semiautomatic Segmentation: A Pilot Study on CBCT Datasets

Inferior alveolar nerve injury is the main complication in mandibular third molar surgery. In this context, cone-beam computed tomography (CBCT) has become of crucial importance in evaluating the relationship between mandibular third molar and inferior alveolar nerve. Due to the growing interest in preoperative planning in oral surgery, several post-processing techniques have been implemented to obtain three-dimensional reconstructions of a volume of interest. In the present study, segmentation techniques were retrospectively applied to CBCT images in order to evaluate whether post-processing could offer better visualization of the structures of interest. Forty CBCT examinations performed for inferior third molar impaction were analyzed. Segmentation and volumetric reconstructions were performed. A dataset composed of multiplanar reconstructions for each study case, including segmented images, was submitted for evaluation to two oral surgeons, two general practitioners and four residents in oral surgery. The visualization of root morphology, canal course, and the relationship with mandibular cortical bone on both native CBCT and segmented images were assessed. Inter-rater agreement showed values of intraclass correlation coefficient (ICC) above 0.8 for all the examined parameters. Oral surgeons presented higher ICC values (p &lt; 0.05). Segmented images can improve preoperative evaluation of the third molar and its relationship with the surrounding anatomical structures compared to native CBCT images. Further evaluation is needed to validate these preliminary results.

Risk factors for external root resorption of maxillary second molars associated with third molars.

PurposeThis study aimed to evaluate the diagnostic performance of panoramic images compared to cone-beam computed tomography (CBCT) imaging for maxillary third molar (M3)-associated external root resorption (ERR), and to identify the risk factors of ERR on panoramic images.Materials and MethodsThe study population was composed of all patients who underwent panoramic imaging at Dankook University Dental Hospital from May to October 2019. In total, 397 cases of maxillary M3s in 247 patients (147 men and 100 women) were included. The diagnostic accuracy of ERR in panoramic images compared to CBCT images was evaluated using the chi-square test. To identify risk factors for ERR, dental records and panoramic findings were evaluated by logistic regression analysis.ResultsThe diagnostic accuracy of ERR on panoramic images was 0.79 compared to CBCT images (P<0.05). Superimposition of M3s onto second molars (M2) was associated with an approximately 33 times higher risk of ERR than separated M3s (P<0.05). Impacted M3s showed a 5 times higher risk of ERR than erupted M3s (P<0.05).ConclusionERR related to M3s is a common clinical condition, and superimposition of M3 onto M2 on panoramic images was the most important risk factor for ERR. It seemed that CBCT examinations for maxillary M3s might be indicated for ERR diagnosis especially if panoramic radiographs show superimposition of M3 onto M2. Impaction itself was also a risk factor, and it should be carefully examined.

Retromolar canals and mandibular third molar position: Is there a possible connection?

Introduction: The retromolar canal (RMC) is an anatomical variation of the posterior part of the mandibular canal. It is thought that this variation is related to histological vestiges of the gubernacular canal and RMC presence may be associated with mandibular third molar (MTM) malposition. This study aims to investigate the relationship between MTM position and RMC existence. Material and Methods: Patients who had undergone cone-beam computed tomography examination for various purposes were included in the study. All of the patients had unilateral or bilateral MTM teeth. MTM impaction patterns were classified according to Winter and Pell-Gregory classifications. RMC existence, type, retromolar foramen (RMF) position, RMF dimensions, and distance from RMF to second and third molars were recorded. Results: Three hundred and forty-six retromolar areas with MTM of 244 patients were evaluated. RMCs were present in 11.5% of the patients. No statistically significant relationship between RMC and MTM impaction patterns was observed. A1-type RMC was found to be the most prevalent. The mean distance from RMF to the third molar was 6.09 ± 4.20 mm and was found to be higher in male patients. The mean distance from RMF to the second molar was 15.28 ± 4.73 mm. The average dimensions of the RMF were 1.4 ± 0.47 mm. Discussion and Conclusion: RMC is a relatively common anatomical variation of the mandibular canal. Although no correlation was observed between MTM impaction pattern and RMC existence, further research including more samples may be helpful to explain a possible correlation.

Evaluating cone-beam CT in the diagnosis of suspected scaphoid fractures in the emergency department: preliminary findings

ObjectivesScaphoid fractures are challenging to accurately diagnose with delayed and missed diagnoses risking poor patient outcomes. Cone beam CT (CBCT) is an emerging technology facilitating alternative access to multi-planar imaging. The aim of this study was to evaluate the use of early CBCT in the diagnosis of suspected scaphoid fractures presenting via the Emergency Department (ED). MethodsIn this single centre the imaging pathway was adapted to include early CBCT in adult patients with a persisting high index of clinical suspicion for scaphoid fracture despite normal radiographs. Evaluation of referrals between September 2019 and February 2020 was undertaken. Statistical analysis and temporal pathway metrics were assessed including interrater agreement for CBCT and radiography examinations. ResultsOver the six-month timeframe 100 CBCT wrist scans were performed on 99 adult patients. 94% of CBCT scans were performed within 1 day of referral. 25% of scans demonstrated acute injuries including 12 radius, 6 trapezium and 2 scaphoid fractures. For fracture, CBCT had a sensitivity of 96.2% and specificity of 100%. There was a highly significant difference in interobserver variation between fracture detection on CBCT and radiographs. ConclusionCBCT heralds the potential for early accurate diagnosis of radiocarpal fractures, at lower cost, shortening clinical pathways and reducing clinical risk in the ED.

Estimating the Entrance Surface Dose in the Eyes, Thyroid, and Parotid Gland Regions in Adult and Pediatric Groups: A Cone-Beam Computed Tomography Technique

Purpose: This study aimed to determine the Entrance Surface Dose (ESD) of sensitive organs in Cone-Beam Computed Tomography (CBCT) imaging of the maxillofacial region in the two age groups of adult and pediatric. Materials and Methods: In this work, the measurements were performed using Thermo Luminescent Dosimeters (TLD-GR200). The imaging was performed using a PROMAX 3D CBCT scanner for 30 adults and 20 pediatric patients. The ESD value for each patient in the region of eyes, thyroid, and parotid glands was measured by 15 TLDs during CBCT of maxillofacial. Results: The highest and lowest mean values of ESDs were related to the parotid and thyroid gland regions in adults, 4.77 ± 0.61 mGy and 0.37 ± 0.16 mGy, respectively. In addition, these values were obtained 2.97 ± 0.36 mGy and 0.35 ± 0.12 mGy in pediatric groups as the highest and lowest values in that order. The results showed that the ESD values of the parotid gland regions in maxilla and mandible examinations had a significant difference (P &lt;0.05). In addition, there was a significant difference between the ESD values of the parotid gland regions among the adults and pediatric groups (P &lt;0.05). Conclusion: According to the results, the ESD values in both age groups were higher in the parotid gland region during maxillofacial CBCT examinations. Therefore, it is recommended to set radiation parameters like mAs as low as possible for reducing the patient dose, especially pediatric patients due to the more sensitive organs.

Cone-beam computed tomography analysis of degenerative changes, condylar excursions and positioning and possible correlations with temporomandibular disorder signs and symptoms

Aim: To describe cone-beam computed tomography (CBCT) features in patients with temporomandibular disorders (TMDs), in terms of degenerative changes, condylar excursions and positioning as well as their possible correlations with signs and symptoms. Methods: Clinical records of patients diagnosed with TMD who were seen between January 2018 and December 2019 were retrospectively evaluated. These patients were divided into the following groups based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD): arthralgia, myalgia, and arthralgia and myalgia groups. The CBCT examination findings of the patients were evaluated in relation to degenerative changes, estimates of condylar excursion, and condylar positioning. The likelihood ratio test was used to verify the possible differences among the three groups, whereas the chi-square test was used to verify the possible differences among the signs and symptoms for the tomographic findings (p ≤ 0.050). Results: In this study, 65 patients with TMD were included. These patients were predominantly female (84.6%) with a mean age of 40.6 years. Tomographic findings of flattening, hyperexcursion and posterior condylar positioning were frequent. A significant correlation was noted between osteophyte and lateral capsule pain (p = 0.027), erosion and posterior capsule pain (p = 0.026), and flattening, pseudocysts (p &lt; 0.050) and condylar excursion (p &lt; 0.001) with mouth opening. Conclusion: Few correlations were noted between degenerative changes and signs of joint pain as well as degenerative changes and condylar hypoexcursion with mouth opening. These correlations were likely associated with division by diagnosis, whereas condylar positioning did not correlate with signs and symptoms.

Association between internal carotid artery calcifications detected as incidental findings and clinical characteristics associated with atherosclerosis: A dental volumetric tomography study

PurposeTo evaluate the presence of calcifications in the internal carotid artery (ICA) in cone-beam computed tomography (CBCT), and to verify the association of these findings with sex, age, dental condition, and risk factors associated with vascular disorders. MethodsThe CBCT scans used in this study were obtained from the database of a private dental clinic requested for the planning of rehabilitation with dental implants. The selection criteria were patients aged 40 years and above. Out of a pool of 1176 CBCT examinations, a total of 284 scans of adult patients were evaluated by two blinded observers. Data were collected from patients' medical records. ResultsICA calcifications were present in 63.0% of the examinations. Most calcifications were in the intracranial pathway (166). Despite being present in a smaller number 57 (C1), extracranial calcifications were more severe. Spearman's ρ coefficients (rS) indicated that the number of missing teeth was directly associated with the presence of calcifications (p = 0.042) and severity (p = 0.020). The age variable also had a direct relationship with the presence of calcifications (p ≤ 0.0001), increasing its frequency and severity over the years. In addition, hypertension (p = 0.036) and use of antihypertensive drugs (p = 0.015) were directly associated. ConclusionsThere is a high occurrence of ICA calcifications in CBCT as incidental findings in adult patients, and it is directly associated with age, number of missing teeth and hypertension.

Three-dimensional comparison of mandibular morphology in young people with Treacher Collins syndrome and Pierre Robin sequence

Treacher Collins syndrome (TCS) and nonsyndromic Pierre Robin sequence (PRS) share mandibular deficiency as a similar clinical finding. This study aimed to compare the mandibular size and morphology of subjects with TCS and PRS. Group TCS was composed of 17 subjects (7 male, 10 female) with a mean age of 11.5years (standard deviation, 4.4) from a single center. Group PRS was composed of 17 subjects paired by age and sex with group TCS. Preorthodontic cone-beam computed tomography examinations of all patients were evaluated using Mimics Innovation Suite 17.0 (Materialise, Leuven, Belgium). Nine 3-dimensional measurements were performed in segmented 3D images of the mandible. Intragroup comparisons were performed using paired t tests. Intergroup comparisons were performed using analysis of variance and Tukey tests. The significance level considered was 5%. TCS showed a significant dimensional difference between less and more affected sides for ramus, condyles, and mandibular body. The mandibular dimensions in PRS were more symmetrical. Group TCS presented a smaller mandibular effective length and mandibular body length compared with PRS. The condyle width and height and the ramus width were also decreased in TCS. The gonial angle was greater in TCS compared with the PRS group. Young subjects with TCS presented a smaller, more vertical, and more asymmetrical mandible compared with nonsyndromic PRS.

Overall stress in periodontal ligament under orthodontic movement during a periodontal breakdown

This research aimed to assess qualitatively and quantitatively the overall stress in the periodontal ligament during gradual periodontal breakdown (0-8 mm) under orthodontic movements. Correlations between the applied forces, the level of bone loss, the decrease of force magnitude, and the increase of stress were also assessed.On the basis of cone-beam computed tomography examinations (voxel size, 0.075 mm), nine 3-dimensional models of a mandibular second premolar with intact periodontium were created and then individually subjected to various levels of horizontal bone loss. Orthodontic forces (intrusion at 0.2 N; extrusion, rotation, and tipping at 0.6 N; translation at 1.2 N) were applied on the brackets. Finite elements analysis was performed, and von Mises (VM) stresses were quantitatively and qualitatively determined.Rotation and translation induced the highest stress apically and cervically, whereas intrusion determined the lowest. Apical stress was lower than cervical stress. In intact periodontium, VM stress was under maximum hydrostatic pressure (MHP) and maximum tolerable stress (MTS). In reduced periodontium, VM stress was lower apically than MHP, whereas cervically, the rotation, translation, and tipping exceeded MHP.A force of 1.2 N seemed safe to be used in the intact periodontium. Forces higher than 0.6 N could produce stresses exceeding MHP and MTS endangering the reduced periodontium. VM stress failure criterion (despite its limited use) seemed to be more adequate for accurate quantitative results. An overall correlation between the applied force, VM stress increase, and periodontal breakdown applicable to all 5 movements could not be established. This was possible only for individual movements.

Impact of cone beam CT on diagnosis of external cervical resorption: the severity of resorption assessed in periapical radiographs and cone beam CT. A prospective clinical study.

To compare the severity of external cervical resorption (ECR) observed in periapical (PA) images and cone beam CT (CBCT) using the Heithersay classification system and pulp involvement; and to assess inter- and intraobserver reproducibility for three observers. CBCT examination was performed in 245 teeth (in 190 patients, mean age 40 years, range 12-82) with ECR diagnosed in PA images. Three observers scored the severity of ECR using the Heithersay classification system (severity class 1-4) and pulp involvement (yes/no) in both PA images and CBCT. Percentage concordance and κ-statistics described observer variation in PA images and CBCT for both inter- and intraobserver reproducibility. For all three observers, the ECR score was the same in the two modalities in more than half of cases (average 59%; obs1: 54%, obs2: 63%, obs3: 61%). However, in 38% (obs1: 44%, obs2: 33%, obs3: 36%) of the cases, the observers scored more severe ECR in CBCT than in PA images (p < 0.001). The ECR score changed to a less severe score in CBCT only in 3% (obs1: 1%, obs2: 4%, obs3: 4%). For pulp involvement, 14% (obs1: 7%, obs2: 20%, obs3: 15%) of the cases changed from "no" in PA images to "yes" in CBCT. In general, κ values were higher for CBCT than for PA images for both the Heithersay classification score and pulp involvement. ECR was generally scored as more severe in CBCT than PA images using the Heithersay classification and also more cases had pulp involvement in CBCT.