Accuracy of Anatomical Depictions in Cone Beam Computed Tomography (CBCT)-Reconstructed Panoramic Projections Compared to Conventional Panoramic Radiographs: A Clinical Risk-Benefit Analysis.

INTRODUCTION: Two-dimensional (2D) radiographs are the standard of care for diagnosis and treatment planning in the day-to-day practice of dentistry. With the growing popularity of cone beam computed tomography (CBCT), it is now becoming the standard of care in many areas of general dentistry due to its ability to create non-linear projections from volumetric data. The CBCT-generated non-orthogonal radiographs can serve as easy-to-use 2D and three-dimensional (3D) diagnostic tools and offer a similar experience for diagnosis as conventional 2D images. The aim of this study is to compare the accuracy of conventional radiographs and CBCT-generated projections to identify relevant anatomic landmarks and their associated variants. METHODS: Thirty-two patients referred to the University of Connecticut School of Dental Medicine's Advanced Imaging Center were selected for this retrospective analysis. Nineteen anatomical landmarks were retrospectively assessed on conventional panoramic and CBCT scans generated panoramic radiographs using two different digital imaging and communications in medicine viewers. A total of 1,216 anatomical landmarks were evaluated by two oral and maxillofacial radiologists to assess the accuracy and consistency of the depiction of radiographic anatomy. RESULTS: There was a very good agreement between the two evaluators with a Cohen's kappa value of 0.934. McNemar change test concluded that the anatomical assessment values compared between conventional panoramic and CBCT-generated panoramic radiographs are similar. CONCLUSION: This study showed that CBCT-generated panoramic images are comparable to conventional panoramic radiographs in identifying anatomical landmarks typically evaluated using a conventional panoramic projection. In addition, they have the added advantage of having 3D information in the acquired volume to better evaluate the area of interest. In clinical situations where a mid- to large-volume CBCT scan is available, a simulated panoramic image can be generated using the CBCT volume, leaving exposure of the patient to the additional radiation of a panoramic image unnecessary.

Evaluating the Efficacy of Certain Intermediate Irrigants in Preventing Precipitate Formed Due to Sodium Hypochlorite and Chlorhexidine Within the Root Canal System: An In Vitro Study.

AIM: Root canal irrigation using a mixture of sodium hypochlorite (NaOCL) and chlorhexidine gluconate (CHX) might cause a precipitate to develop. This study aims to check the efficacy of sodium thiosulfate and normal saline as irrigating solutions. MATERIALS AND METHODS: Roots of 45 teeth were biomechanically prepared, and the teeth were then tested. A size 15k file was introduced to the point where the apical foramen could be visible in order to provide an accurate reading of the working length. As a precaution against irrigating solutions leaking out, the specimens' tips were sealed with modeling wax before being instrumented. Each group's root canals were instrumented with #F4 hand Protaper (Dentsply Sirona, USA) as recommended by the manufacturer. Between instrumentation, The canals were lubricated with ethylenediamine tetraacetic acid (EDTA) and irrigated with 2.5% sodium hypochlorite (RC Help, Prime Dental, Mumbai, India). Fifteen samples were randomly assigned to one of three experimental categories based on the middle watering arrangement used: Group 1 (control), Group 2 (saline irrigant), and Group 3 (3.86% sodium thiosulfate). The jewel plate was submerged in water to cool it down, while two longitudinal scores were made on the root's buccal and lingual surfaces. We used a stereomicroscope to examine the exposed surfaces of the root trench in the coronal, middle, and apical thirds for the orange-earthy colored material (Stereozoom Nikon magnifying lens under 20X amplification), and we used the Mann-Whitney U test and the Kruskal Wallis test during our thorough analysis. RESULTS: The precipitation generated in the coronal, middle, and apical thirds had significantly different thicknesses. While precipitation did occur in all three regions, it was at a much lower rate in the apical third compared to the coronal and middle regions. In Group 1, the control group, the precipitate was thicker than in Groups 2 (saline irrigant) and 3 (3.86% sodium thiosulfate). CONCLUSION: Sodium thiosulfate, which is a biocompatible solution, can be used as an intermediate irrigant as it shows less precipitate as compared to saline.

Aggressive Cutaneous Squamous Cell Carcinoma of the Head and Neck: A Review.

Non-melanoma skin cancer of the head and neck (NMSCHN) is one of the most common malignancies worldwide, and its incidence is growing at a significant rate. It has been found to be aggressive in its spread and has the capacity to metastasize to regional lymph nodes. Cutaneous squamous cell carcinoma (cSCC) has a considerably high mortality rate. It has remarkable characteristics: diameter >2 cm, depth >5 mm, high recurrence, perineural invasion, and locoregional metastases. Aggressive cSCC lesions most commonly metastasize to the parotid gland. Also, immunocompromised patients have a higher risk of developing this aggressive cancer along with the worst prognostic outcomes. It is very important to discuss and assess the risk factors, prognostic factors, and outcomes of patients with cSCC, which will give clinicians future directives for making modifications to their treatment plans. The successful treatment of aggressive cSCC of the head and neck includes early detection and diagnosis, surgery alone or adjuvant chemotherapy, and radiotherapy as required. Multimodal therapy options should be considered by clinicians for better outcomes of aggressive cSCC of the head and neck.

Oral manifestation of Waardenburg syndrome: a case report and review of the literature.

Waardenburg syndrome is a rare autosomal dominant genetic disorder of neural crest cell migration. It is characterized by congenital sensorineural hearing loss, heterochromia iridis, depigmentation of hair and skin, and increased intercanthal distance. It is subdivided into four subtypes with I and II being most common. These subtypes are categorized based on genetic mutations. Although medical literature has well documented this syndrome, dental and radiographical findings have been rarely presented. In this case report and literature review, we have presented and discussed oral as well as head and neck radiology findings of a 20-year-old girl with Waardenburg syndrome.

Dynamically Navigated versus Freehand Access Cavity Preparation: A Comparative Study on Substance Loss Using Simulated Calcified Canals.

INTRODUCTION: The aim of this in vitro study was to compare the speed, qualitative precision, and quantitative loss of tooth structure with freehand and dynamically navigated access preparation techniques for root canal location in 3-dimensional-printed teeth with simulated calcified root canals. METHODS: Forty maxillary and mandibular central incisors (tooth #9 and tooth #25) were 3-dimensionally printed to simulate canal calcification. Under simulated clinical conditions, access preparations were randomly performed with contemporary freehand and dynamically navigated techniques. Qualitative precision and quantitative loss of tooth structure were assessed on postoperative cone-beam computed tomographic scans using ITK-SNAP open-source segmentation (http://www.itksnap.org/). The associations between jaw, technique, volume of substance loss, and operating time were determined using analysis of variance models with Tukey-adjusted post hoc pair-wise comparisons. The kappa statistic was used to determine agreement between 2 independent, blinded raters on the qualitative assessment of the drill path. The association between the technique and jaw and qualitative assessment scoring was compared using the Fisher exact test. The significance level was set at .05. RESULTS: Dynamically navigated accesses resulted in significantly less mean substance loss in comparison with the freehand technique (27.2 vs 40.7 mm3, P < .05). Dynamically navigated accesses were also associated with higher optimal precision (drill path centered) to locate calcified canals in comparison with the freehand technique (75% vs 45%, P > .05). Mandibular teeth were associated with a negligible difference in substance loss between the access techniques (19.0 vs 19.1 mm3, P > .05). However, qualitatively the freehand technique was still prone to 30% higher chance of suboptimal precision (drill path tangentially transported) in locating calcified canals. Overall, dynamically navigated accesses were prepared significantly faster than freehand preparations (2.2 vs 7.06 minutes, P < .05). CONCLUSIONS: Within the limitations of this in vitro study, overall dynamically navigated access preparations led to significantly less mean substance loss with optimal and efficient precision in locating simulated anterior calcified root canals in comparison with freehand access preparations.

Cone-Beam Computed Tomography Analysis of the Prevalence, Length, and Passage of the Anterior Loop of the Mandibular Canal.

When placing implants in the anterior mandible, it is important to avoid damaging the mandibular nerve and its terminal extensions. The objective of this study was to determine the prevalence, length, and passage of the anterior loop of the mandibular canal, as well as the quantity of alveolar bone that is coronal to the canal, to help with implant placement in the anterior mandible. Cone-beam computerized tomography (CBCT) scans of 124 patients with 248 hemi-sections were evaluated. Anterior loop prevalence was determined using reconstructed panoramic and cross-sectional views; length was measured as the distance between the most mesial aspect of the mental foramen to the most mesial aspect of the anterior loop on cross-sectional views. The bucco-lingual position of the anterior loop inside the mandible and the apico-coronal dimensions of the alveolar bone above it were measured on cross-sectional views to determine the passage of the anterior loop and the bone available coronally, respectively. The effects of sex, age, side, and dentate status on the prevalence and length of the anterior loop were analyzed statistically. Prevalence of the anterior loop at the patient and hemi-section levels was 25% and 24%, respectively, and its median length was 1.63 mm (range, 0.52-3.92 mm). The anterior loop was apical to the mental foramen and mostly located within the buccal or middle one-third of the alveolar ridge, with an average height of coronal alveolar bone of 17.12 mm. Sex, age, side, and dentate status did not affect anterior loop prevalence and length. In conclusion, because of great variation, a case-by-case CBCT evaluation of the anterior loop is necessary before placing implants in the anterior mandible.

Comparison of Efficiency and Image Quality of Photostimulable Phosphor Plate and Charge-Coupled Device Receptors in Dental Radiography.

The photostimulable phosphor (PSP) plate and charge-coupled device (CCD) are receptors commonly used for intraoral radiography in U.S. dental schools. However, it is unclear which receptor is more beneficial for radiology education and patient care in an academic setting. The aim of this study was to compare the time efficiency, image quality, and operator performance for student-operated PSP plate and CCD receptors. At one U.S. dental school in 2018, 20 dental hygiene and dental students (n=10 each) were recruited as operators. They each exposed anterior and posterior periapical and bitewing radiographs on dental radiograph teaching and training replica using the PSP plate and CCD as receptors. The time taken to expose the radiographs was recorded. Image sharpness/definition, brightness/contrast, and technical errors, including placement, angulation, and cone cut errors, were evaluated on a three-point scale with 0=non-diagnostic, 1=diagnostic acceptable with minor errors, and 2=perfect diagnostic quality. The results showed that it was generally faster for the students to expose intraoral radiographs with CCDs than with PSP plates, although the difference was not significant (p>0.05). Image quality and technical accuracy, especially angulation, were significantly superior for PSP relative to CCD (p<0.05). This study found that PSP imaging was of higher quality and accuracy than CCD, whereas CCD was more efficient. Dental and dental hygiene students would benefit from being trained on both receptors to be able to adapt to a diversified workplace.

Multiple intraosseous cervical pneumatocysts: A case report of a rare incidental finding on cone-beam computed tomography.

This report presents a case of cervical pneumatocysts as an incidental finding on cone-beam computed tomography. Pneumatocysts are gas-containing lesions of unknown etiology. They usually present in the ilium or sacrum, adjacent to the sacroiliac joint. In the literature, 21 case reports have described cervical pneumatocysts. Cervical pneumatocysts should be differentiated from other lesions, such as osteomyelitis, osteonecrosis, and neoplasms, as well as post-traumatic and post-surgical cases. Computed tomography, cone-beam computed tomography, and magnetic resonance imaging are appropriate tools to diagnose cervical pneumatocysts.

Multidisciplinary approach for reconstruction of cranial defect with polymethyl methacrylate resin reinforced with titanium mesh.

Cranial defects occur most commonly as a sequelae to trauma, the incidence being as high as 70%. The successful management of a case of trauma in an emergency situation requires quick evacuation of the hematoma, repair of the dura, and the scalp but not necessarily the integrity of the calvarial segment as an immediate measure. So the reconstruction of the calvarial defect in these cases is mostly carried out as a secondary procedure. Various materials are used for reconstruction of cranial defects, polymethyl methacrylate (PMMA) resin being one of them. In this article, we report a case which was successfully treated by PMMA resin in combination with a titanium mesh for reconstruction of the cranial defect as a secondary procedure.

Cone Beam CT Analysis of Tempora Bone Pneumatizatioi in Subjects with Unilateral Cleft Lip and Palate.

OBJECTIVES: To evaluate the pneumatization pattern in the temporal bone in patients with cleft lip and palate. METHODS: A retrospective observational analysis of cone beam computed tomography (CBCT) scans of patients with cleft lip and palate was done. The patients were referred for orthodontic treatment and had a unilateral cleft lip and palate and anterior maxillary constriction. Four reference structures were identified to evaluate the extension of pneumatization in the cleft vs non-cleft side temporal bones. RESULTS: Twenty patients had cleft on the left side and nine patients had cleft on the right side, This study found reduced temporal bone pneumatization on the side of the cleft. The mean score of temporal bone pneumatization on the cleft side was 4.7±1.47 while mean score of pneumatization on the non-cleft side was 6.7±1.80 (P<0.001). CONCLUSIONS: Pneumatization of the temporal bone was significantly lower on the side of the cleft and an identification of this change can help in early diagnosis and management of any ear-related conditions in this vulnerable group of patients to make appropriate referrals for specialized care.

Radiographic evaluation of the maxillary sinus prior to dental implant therapy: A comparison between two-dimensional and three-dimensional radiographic imaging.

PURPOSE: This study was performed to evaluate the diagnostic efficacy of panoramic radiography and cone-beam computed tomography (CBCT) in detecting sinus pathology. MATERIALS AND METHODS: This study was based on a retrospective evaluation of patients who had undergone both a panoramic radiograph and a CBCT exam. A total of 100 maxillary sinuses were evaluated. Four examiners with various levels of expertise evaluated the images using a five-point scoring system. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of the two modalities. The image analysis was repeated twice, with at least two weeks between the evaluation sessions. Interobserver reliability was assessed using Cronbach's alpha, and intraobserver reliability was assessed using Cohen's kappa. RESULTS: Maxillary sinus pathology was detected in 72% of the patients. High interobserver and intraobserver reliability were observed for both imaging modalities and among the four examiners. Statistical analyses using ROC curves demonstrated that the CBCT images had a larger area under the curve (0.940) than the panoramic radiographs (0.579). CONCLUSION: Three-dimensional evaluation of the sinus with CBCT was significantly more reliable in detecting pathology than panoramic imaging.

Artifacts in Cone Beam Computed Tomography Image Volumes: An Illustrative Depiction.

INTRODUCTION: The evolution of cone beam computed tomography (CBCT) has brought about a paradigm shift in radiographic evaluation of the maxillofacial skeleton. Because of its low cost, high resolution, and relatively low-radiation dose, CBCT is fast becoming the 3-D imaging modality of choice in dentistry. The ubiquitous availability of this new imaging modality poses unique challenges in understanding this technology and recognizing the associated artifacts that present themselves in the acquired image volumes. There are several artifacts that are inherent to CBCT scans by virtue of the physics behind their acquisition and image reconstruction algorithms. BACKGROUND: An image artifact may be defined as a visualized structure in the reconstructed data that was not originally present in the object or the imaged area of interest. It can be explained as any distortion or error in the image that is unrelated to the subject being studied. Artifacts are induced by discrepancies between the physical conditions of the measuring setup, which is usually the CBCT scanner's technical composition and position of the object under investigation. OBJECTIVE: The objective of this study is to present an illustrative depiction of the most commonly encountered CBCT artifacts with an explanation of how each artifact is caused and how it presents itself in CBCT image volumes. CONCLUSION: Because these artifacts cause significant image degradation and often misrepresent the region of interest, they should be recognized, understood, and taught along with normal CBCT anatomy to facilitate accurate evaluation of the image volumes and prevent inaccurate diagnoses.

A comparative study between currently used methods and Small Volume-Cone Beam Tomography for surgical placement of mini implants.

OBJECTIVE: To compare the outcome of mini implant placement by four different methods: blind placement, a single periapical radiograph (PA), a single panoramic radiograph, and a small-volume cone-beam computed tomography (SV-CBCT). Our hypothesis was that SV-CBCT, with its high resolution, low radiation dose, and three-dimensional depiction of area of interest would yield superior diagnostic information in assessing the potential anchorage site compared to currently used methods that often result in undesired root perforations. MATERIALS AND METHODS: Potential mini implant sites of 20 dentate or partially dentate human skulls were imaged using three different imaging modalities: PA, panoramic radiograph, and SV-CBCT. Mini implants were placed in 10 maxillary and 10 mandibular randomized sites blindly and using each of the three imaging modalities. Large-volume CBCT scans done postoperatively were used to detect root perforation. Two oral radiologists analyzed the images for perforation of root structures at each site. RESULTS: There was significantly (P < .05) less root perforation with SV-CBCT when compared with other imaging modalities. Fifty-five percent of mini implants placed blindly, 60% of mini implants placed using PA, and 50% of mini implants placed using a panoramic radiograph perforated a root structure, whereas only 5% of mini implants placed using SV-CBCT perforated a root structure. CONCLUSIONS: Preoperative evaluation of potential mini implant insertion sites using SV-CBCT aids in predictable placement and results in the least amount of root perforation.

Chronic osteitic rhinosinusitis as a manifestation of cystic fibrosis: A case report.

A 28-year-old male patient with a history of cystic fibrosis (CF) was referred to the University of Connecticut School of Dental Medicine for an evaluation of a cystic lesion in the right maxilla using cone-beam computed tomography (CBCT). CF is an autosomal recessive disease characterized by an abnormal production of viscous mucus, affecting the mucociliary clearance. The CBCT scan revealed a large cystic lesion in the right maxilla extending from the right maxillary second molar to the midline in the region of the right central incisor with a significant buccal expansion. Further evaluation revealed complete opacification of the paranasal sinuses with medial bulging of the lateral maxillary sinus walls. The maxillary and sphenoid sinuses also appeared hypoplastic. The peculiar finding seen in this case was the presence of marked sclerosis and an increase in the thickness of the adjacent bony framework. This report aimed to describe the common sinonasal findings associated with CF and its underlying pathophysiology.

Clival lesion incidentally discovered on cone-beam computed tomography: A case report and review of the literature.

An osteolytic lesion with a small central area of mineralization and sclerotic borders was discovered incidentally in the clivus on the cone-beam computed tomography (CBCT) of a 27-year-old male patient. This benign appearance indicated a primary differential diagnosis of non-aggressive lesions such as fibro-osseous lesions and arrested pneumatization. Further, on magnetic resonance imaging (MRI), the lesion showed a homogenously low T1 signal intensity with mild internal enhancement after post-gadolinium and a heterogeneous T2 signal intensity. These signal characteristics might be attributed to the fibrous tissues, chondroid matrix, calcific material, or cystic component of the lesion; thus, chondroblastoma and chondromyxoid fibroma were added to the differential diagnosis. Although this report was limited by the lack of final diagnosis and the patient lost to follow-up, the incidental skull base finding would be important for interpreting the entire volume of CBCT by a qualified oral and maxillofacial radiologist.

Classification and volumetric analysis of temporal bone pneumatization using cone beam computed tomography.

OBJECTIVE: This study performed volumetric analysis and classified different repeated patterns of temporal bone pneumatization in adults using cone beam computed tomography (CBCT) scans. STUDY DESIGN: A total of 155 temporal bones were retrospectively evaluated from 78 patients with no radiographic evidence of pathology. Two reference structures were used to classify temporal bone pneumatization into 3 groups. Volumetric analysis of the pneumatization was performed using a window thresholding procedure on multiplanar CBCT images. Correlation between direct communication of peritubal cells with the eustachian tube and the degree of pneumatization was also assessed. RESULTS: Using 2 reference structures, pneumatization pattern in the temporal bone can be classified into 3 groups. Statistically significant differences were present in their mean volumes between 3 groups. Statistically significant correlation was found between degree of pneumatization and presence of peritubal cells associated with ET. CONCLUSIONS: This study showed that CBCT can be effectively used for imaging temporal bone air cavities and for volumetric assessment.