Showing papers in "Oral Radiology in 2009"

The effect of voxel size on image reconstruction in cone-beam computed tomography

Abstract: Objectives This study evaluated the effects of changing the voxel size on the resolution and noise of cone-beam computed tomography (CBCT) reconstruction images.

Remodeling of the human mandible in the gonial angle region: a panoramic, radiographic, cross-sectional study

Abstract: Changes in the gonial angle in relation to age, gender, and dental status were studied. The study cohort comprised 1000 patients (500 males and 500 females) who had panoramic radiographs taken for various purposes. The patients were categorized according to age, gender, and dental status. Panoramic radiographs were traced, and gonial angles were measured using a protractor. The gonial angle tended to increase with age in both the male and female patients. The gonial angle also increased significantly as dental status changed from completely dentulous to partially dentulous to completely edentulous. The gonial angle increases with age and as teeth are lost.

Prevalence and characteristics of intracoronal resorption in unerupted teeth in the permanent dentition: a retrospective study

Abstract: To determine the prevalence, types of teeth, and distribution of intracoronal resorption in permanent dentition in a large population. A total of 9,570 panoramic radiographs were screened, and 2,922 unerupted teeth were examined. The prevalence of intracoronal dentine defects was 1.55% in subjects and 0.95% in teeth. The highest prevalence of intracoronal radiolucencies was noted in the mandibular second molar (9.5%), followed by the maxillary second premolar tooth (4.7%). To our knowledge, this is the first report of coronal radiolucency in maxillary supernumerary teeth. Of the lesions identified, 39.3% were two-thirds of the dentine thickness, and 21.4% included the enamel; 85.7% of the defects were located at the central aspect of the crown. Ectopically positioned teeth showing intracoronal resorption accounted for 14.3% of the cases. Intracoronal resorption in an unerupted tooth occurs frequently and can be seen in more than one tooth in an individual. This condition is usually associated with not only an ectopic position but also resorption, which may be a progressive process. Dental clinicians should conduct periodic follow-ups, both clinical and radiographic, of these unerupted teeth.

An oral rehabilitation robot for massaging the masseter and temporal muscles: a preliminary report

Abstract: This study determined suitable conditions for masseter and temporal muscle massage using a specially fabricated robot and evaluated its effects on patients with TMJ dysfunction associated with myofascial pain. The robot was designed with two arms with six degrees-of-freedom, and equipped with plungers. A phase-1 trial examined 22 healthy volunteers to determine its safety and suitable massage pressure, examining three different pressures. The volunteers evaluated their comfort, warmth, and ease of mouth opening by use of a visual analogue scale (VAS). A phase-2 trial examined the safety, suitable dose regimen, and efficacy in 12 patients. Maximal mouth opening was measured, and muscle pain and massage were evaluated subjectively. The robot was safe in the phase-1 trial, except for two massages in which the pressure was excessive. Massages at 6–10 N were given the highest VAS scores. In phase 2, the massage pressure was arbitrary and each muscle was massaged seven times for 1 min, three times every two weeks. After evaluating the efficacy, additional treatments were performed at a greater pressure or for longer. The massage treatment was very effective for most patients. The massage treatment was safe and effective for most patients when administered at a pressure of 6–10 N seven times for 1 min per muscle every two weeks. The robot may constitute a useful tool for treating TMJ dysfunction associated with myofascial pain.

The frequency of distomolar teeth in a population of urban Turkish adults : a retrospective study

Abstract: Objectives To determine the frequency, location, and shape of distomolar teeth in a population of urban Turkish adults.

The relationship between panoramic radiomorphometric indices and the femoral bone mineral density of edentulous patients

Abstract: Objectives To determine the relative efficacy of panoramic radiomorphometric indices in detecting osteoporosis, and optimal thresholds for referral for osteoporosis investigation in edentulous patients.

Imaging diagnosis of the temporomandibular joint: critical review of indications and new perspectives

Abstract: In recent decades, there have been important developments in temporomandibular joint (TMJ) imaging. New techniques complement preexisting methods, and each modality is indicated for specific conditions in accordance with the clinical diagnosis. The aim of this review is to give an overview of conventional and new techniques in TMJ imaging. The literature review includes studies published between 1976 and 2009 that appear in the Medline database. Magnetic resonance imaging remains the “gold standard” modality for TMJ analysis. It allows structures to be visualized without radiation whether or not they are mineralized; however, it is costly and complex. Ultrasonography, an alternative method with increasing importance in TMJ analysis, is a simple, noninvasive, and low-cost technique that allows for the visualization of the position of the disk; however, it does not detect condylar abnormalities. Reconstructions in three-dimensions can be obtained with computed tomography, magnetic resonance imaging, and ultrasonography and can be used to obtain rapid prototyping biomodels. Health professionals performing TMJ imaging exams should consider clinical history and findings, exam cost, radiation exposure, results of previous exams, and whether the current result will influence diagnosis and treatment planning.

Comparison of two- and three-dimensional filtering methods to improve image quality in multiplanar reconstruction of cone-beam computed tomography

Abstract: Objectives Two- and three-dimensional (2D and 3D, respectively) filtering methods were examined to improve the accuracy of bone morphology depicted in dental cone-beam computed tomography (CBCT) images. An attempt to improve multiplanar reconstruction (MPR) image quality was carried out by reducing the image noise.

MRI evaluation of the classification, frequency, and disc morphology of temporomandibular joint disc displacements: a multicenter retrospective study in a Turkish population

Abstract: Objectives Magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ) and temporomandibular disorders (TMDs) have been discussed in detail for various populations. As no such study has examined the Turkish population, we determined the frequency of TMDs in the Turkish population through a multicentric investigation using MRI.

Reliability of a coordinate system based on anatomical landmarks of the maxillofacial skeleton: an evaluation method for three-dimensional images obtained by cone-beam computed tomography

Abstract: We propose a method for evaluating the reliability of a coordinate system based on maxillofacial skeletal landmarks and use it to assess two coordinate systems. Scatter plots and 95% confidence ellipses of an objective landmark were defined as an index for demonstrating the stability of the coordinate system. A head phantom was positioned horizontally in reference to the Frankfurt horizontal and occlusal planes and subsequently scanned once in each position using cone-beam computed tomography. On the three-dimensional images created with a volume-rendering procedure, six dentists twice set two different coordinate systems: coordinate system 1 was defined by the nasion, sella, and basion, and coordinate system 2 was based on the left orbitale, bilateral porions, and basion. The menton was assigned as an objective landmark. The scatter plot and 95% ellipse of the menton indicated the high-level reliability of coordinate system 2. The patterns with the two coordinate systems were similar between data obtained in different head positions. The method presented here may be effective for evaluating the reliability (reproducibility) of coordinate systems based on skeletal landmarks.

Bilateral multiple tonsilloliths

Abstract: Tonsilloliths or tonsil stones are calcifications that form in the crypts of the palatal tonsils. These calculi are composed of calcium salts, alone or in combination with other mineral salts, and are usually small, although there have been occasional reports of large tonsilloliths or calculi in peritonsillar locations. Most often, these calculi are asymptomatic and small, often detected only by computed tomography (CT), although large calculi may be visible in routine panoramic radiographs. Although tonsilloliths normally do not require medical attention, they may become large enough to cause a variety of symptoms requiring treatment. Here, we report the case of a 45-year-old male with difficulty opening the mouth and previous treatment for carcinoma of the left buccal mucosa 6 years earlier. Routine orthopantomography revealed large, bilateral, radiopaque areas over the ramus of the mandible. A diagnosis of multiple tonsilloliths was made after confirming the exact location of the radiopacities on CT.

Trifid mandibular condyle

Abstract: Bifid and trifid condyles are rare disorders of the mandible. Their etiology and pathogenesis are unclear. They can be associated with temporomandibular joint disorders or can be diagnosed incidentally on routine radiographic examination. This article presents a case of trifidism of the right mandibular condylar head of a 31-year-old woman with a history of childhood trauma to the head and neck. The patient was asymptomatic. The abnormal formation of the condyle was diagnosed incidentally on a panoramic radiograph and was evaluated using cone-beam computed tomography.

Ameloblastic fibro-odontoma arising in the mandible: three case reports

Abstract: Ameloblastic fibro-odontoma is a rare mixed odontogenic tumor Here, we describe three cases of ameloblastic fibro-odontoma We present both conventional radiography and computed tomography (CT) images from two cases and conventional radiography from one case Given the CT values of the tumor’s radiopaque components, CT was very useful for the diagnosis of ameloblastic fibro-odontoma

Computed tomographic anatomy of the mandibular first and second molars and their surrounding structures in the spread of odontogenic infection

Abstract: Objectives The purposes of this study were to analyze the CT anatomy of the mandibular first and second molars in uninfected subjects and to clarify the pathway of odontogenic infection originating from the mandibular first and second molars.

Fibrosarcoma of the mandible: case report of a unique radiographic appearance

Abstract: Fibrosarcoma is a rare malignant fibroblastic neoplasm that only rarely affects the oral cavity. Here, we describe a rare case of fibrosarcoma affecting the mandible of a 10-year-old girl. Orthopantomography showed a well-defined radiolucency with a cortical rim typical of a benign lesion. However, occlusal radiographs showed Codman’s triangle, indicating the malignant nature of the lesion. Computed tomography showed a radiolucent lesion involving the buccal aspect of the mandible, and histopathological examination confirmed the diagnosis. The patient underwent surgical resection of the tumor and is currently undergoing regular follow-up examinations.

CT analyses of the location of the maxillary third molar in relation to panoramic radiographic appearance

Abstract: We compared the relationship between anatomical structures analyzed by panoramic radiographs and CT images of uninfected impacted maxillary third molars and investigated the pathway of infection originating from pericoronitis of maxillary third molars. Patients (n = 62) with uninfected impacted maxillary third molars and patients (n = 8) with odontogenic infection originating from pericoronitis of the maxillary third molars were selected from an image database. CT and panoramic images were evaluated separately by an oral surgeon and a radiologist for the vertical position of the tooth, the presence of bone around the crown, proximity to the maxillary sinus, visibility of masticatory muscles, and mesiodistal and buccopalatal inclinations. In uninfected patients, a significant correlation was observed between the vertical positions evaluated by the two methods. Of the third molars, 79 (63.7%) were identified as vertical type on both panoramic and CT images. Regarding the maxillary sinus, of the 19 molars classified as the separate type on panoramic images, 2 (10.5%) were identified as the close type on CT. CT examination revealed the involvement of buccal cortical plates and the buccal space in the majority of infected patients. CT images revealed that 94 molars (75.8%) showed vertical type on the buccopalatal inclination and that 45 impacted molars (36.3%) showed bone defects in the buccal area. Infections originating from pericoronitis of the maxillary third molar showed involvement of the buccal cortical plates, the buccal space, and other spaces, which were clearly depicted on CT images.

Unusual teeth transpositions: two case reports

Abstract: Tooth transposition is a rare dental anomaly that is characterized by the interchanged position of two adjacent permanent teeth in the same quadrant or ectopic eruption of one tooth in the place of another This article presents two case reports of transpositions In the first case, a 21-year-old man presented with a left maxillary canine to molar site transposition Radiographs showed that the canine was transposed completely In the second case, a 35-year-old man presented with a right mandibular second premolar that had erupted between the first and second molars Radiographs showed that the second premolar was positioned between the first and second molars Maxillary canine to first molar site transpositions are extremely rare To date, just eight cases have been reported in the English literature Early loss of the first permanent molar may trigger distal migration of a developing canine bud A mandibular second premolar erupting between the first and second molars is also a rare position anomaly that has not been reported in the English literature

Computer-based videofluorographic analysis of posterior pharyngeal wall movement during swallowing in patients with head-and-neck cancer

Abstract: We sought to develop a method for evaluating dysphagia using videofluorography (VF) by analyzing the time course of changes in pharyngeal wall movement and to assess patients with head-and-neck cancer before and after surgery. The subjects were 14 patients diagnosed with head-and-neck cancer. We obtained VF images before and after surgery and analyzed them with two-dimensional video measurement software. Then, we calculated dysfunction scores based on the remaining or aspiration amount of sample by interpreting the VF images. We found dysmotility of the posterior pharyngeal wall in some postoperative cases. Inter- and intrarater reproducibility was high in the evaluation of posterior pharyngeal wall movements. A significant difference was found in the scores between the patients showing dysmotility of the posterior pharyngeal wall and no dysmotility. We developed a reproducible method for evaluating movements of the posterior pharyngeal wall during swallowing using VF. This may become a useful tool for objectively evaluating VF data.

Fronto-orbital sphenoethmoidal fibrous dysplasia

Abstract: Cranial fibrous dysplasias (FDs) are rare and comprise less than 1% of all primary bone lesions. They may produce cosmetic deformities, peripheral compressive cranial neuropathies, and compressive central neurologic manifestations. We describe an unusual presentation of a fronto-orbital sphenoethmoidal FD in a 32-year-old woman with conventional radiographic, CBCT, and MRI findings. In the head and neck examination, an asymmetry was noticed on the left side, without evidence of adenopathy, paresthesia, or motor nerve deficiency. Panoramic radiographs showed a radiopaque expanded bone in the region of the posterior maxillary sinus and orbita. Computed tomography with three-dimensional reconstruction demonstrated an expanding lesion of the cranial bones, involving the ethmoid and periorbital bone, producing a ground-glass appearance. After the radiologic examination, the patient was referred for surgery with a diagnosis of cranial FD and underwent a cranioplasty. The CT and MRI features were typical for FD, but physicians and dental professionals should be aware of this diagnosis, even if no symptom is apparent and the patient came in only for a routine dental examination. Maxillofacial radiologists should also consider that the signal intensity on both T1- and T2-weighted images and the degree of contrast enhancement on T1-weighted images depend on the amount and degree of bony trabeculae, cellularity, collagen, and cystic and hemorrhagic changes.

A fast Look-Locker method for T 1 mapping of the head and neck region

Abstract: A sequence for T 1 relaxation time measurements that allows a high-resolution image to be obtained within a short acquisition time is described. Its application to the orofacial region is investigated. The sequence is based on the Look–Locker (LL) method and employs a magnetization-preparation pulse prior to data acquisition, with either a turbo-field echo (TFE) or turbo-field echo echo-planar imaging (TFEPI) sequence. We applied the multiple LL sequence by synchronizing the data acquisition with the virtual electrocardiogram. T 1 results from the LL sequence were compared with those from the inversion recovery (IR) sequence. In an in vitro study, we evaluated the T 1 maps of contrast medium at different concentrations. In an in vivo study, we evaluated the T 1 maps in seven volunteers. In the in vitro study, the correlation between the T 1 values obtained from the LL sequence and those from the IR sequence was high, with an R 2 of more than 0.99. For T 1 values between 200 and 1,500 ms, the difference between the two methods was less than 7%. In the in vivo study, a high correlation was observed between the T 1 values from the IR sequence and those from the LL sequence. The scan duration for the LL sequence was less than 3 min. Our method, based on the LL sequence, was found to be clinically useful for producing a T 1 map.

An unusual case of hemifacial microsomia with overgrowth of the facial muscles

Abstract: To present a case of severe hemifacial microsomia with unusual muscle overgrowth at presentation. The patient, a 9.5-year-old girl, presented to an orthodontist for treatment. Clinically, the patient had hypoplasia and dysmorphogenesis of the facial skeleton. Radiographs revealed overgrowth of the muscles of the face instead of muscle and soft-tissue hypoplasia on the affected side. The observed muscle hyperplasia did not fall into the generally accepted classification of hemifacial microsomia. This finding has not been reported previously.

Radionuclide scan imaging of bilateral Warthin’s tumor and chronic inflammation in the submandibular glands of a patient with a history of heavy smoking

Abstract: Papillary cystadenoma lymphomatosum, or Warthin’s tumor, is a benign tumor, primarily localized in the parotid glands. The tumor is more common in men than women, and it occurs usually in the fifth and sixth decades of life. Smoking seems to be one of the predisposing factors. The case of a 65-year-old man is described; he presented with a chief complaint of swelling in the bilateral parotid and submandibular glands. Imaging revealed a benign tumor in the right parotid gland, but only inflammation in both submandibular and the left parotid glands. A biopsy was carried out after rapidly increased swelling of the left parotid and left submandibular glands. Histopathological examinations revealed chronic sialadenitis. Superficial parotidectomies were performed 7 and 21 months after the initial visit on the right parotid and the left parotid glands, respectively. Histopathological examination revealed Warthin’s tumor in both parotid glands, with fibrogenesis and chronic sialadenitis in the submandibular glands.

Assessment of 3,031 panoramic radiographs in an urban Turkish population: a community survey

Abstract: Objectives The present study was performed to assess the total and average numbers of radiopaque restorations, missing or impacted teeth, root-canal fillings, crown-fixed partial dentures, and implants in 3,031 radiographs of patients with respect to age and gender in an urban Turkish population.

Converting conventional radiographic examination data of trabecular bone pattern values into density measurement values using intraoral digital images

Abstract: Objectives To determine the conversion value of grayscale density measurements from intraoral conventional radiographic examinations of the edentulous maxilla and mandible using intraoral digital radiography.

Utility of re-windowing for MR T2-weighted images in differentiating between benign tumors and cysts

Abstract: Both benign tumors and cysts in the oral and maxillofacial region show clear borders and homogeneously high signal intensity on magnetic resonance (MR T2-weighted images, making differentiation difficult without contrast enhancement. Windowing for brightness and contrast adjustment may be helpful in interpreting relative signal intensities on MR images. This study was performed to determine whether re-windowing against targeted lesions on T2-weighted images was a useful procedure that would enhance differentiation without invasive contrast enhancement. Twenty-six lesions (13 benign tumors, 13 cysts) that showed clear borders and homogeneously high signal intensity on T2-weighted images were examined. The windowing parameters of axial images were readjusted to emphasize contrast only inside the lesions using automatic density adjustment. Re-windowed images were reviewed by three experienced oral radiologists and categorized based on the internal homogeneity of the lesion into four grades: 0, heterogeneous; 1, slightly heterogeneous; 2, slightly homogeneous; 3, homogeneous. Re-windowing was then evaluated for its usefulness in differentiating between benign tumors and cysts. For cysts, the rates of homogeneous (grades 3 and 2) and heterogeneous intensity (grades 1 and 0) were 66.7 (26/39) and 33.3% (13/39), respectively. For benign tumors, these rates were 33.3 (13/39) and 66.7% (26/39), respectively. Cysts showed a higher rate of homogeneous intensity, while the opposite was true for benign tumors. A significant difference in distribution was observed between cysts and benign tumors (P < 0.01, χ 2 test). Re-windowing for T2-weighted images is helpful in differentiating between benign tumors and cysts with clear borders and homogeneously high signal intensity on T2-weighted images.