Biomedical subjects

Eiichiro Ariji

Publications and source records attributed to Eiichiro Ariji.

At least 19 recordsLinked to original sources

PubMed2006

3D-CT evaluation of facial asymmetry in patients with maxillofacial deformities.

OBJECTIVE: The aims of this study were to characterize the symmetrical features of patients with facial deformities and to suggest a classification system for facial asymmetry based on 3-dimensional-computed tomography (3D-CT) evaluation. STUDY DESIGN: Preoperative CT images were investigated for 49 patients with maxillofacial deformities. Asymmetry indices were calculated for some landmarks in the maxilla, mandibular body and the mandibular ramus regions. RESULTS: Asymmetry was observed most frequently in the mandibular body region. The subjects were divided into 3 groups. Subjects without any asymmetry in the 3 regions were classified as Group I (44.9%). Groups II or III were defined for subjects without or with maxillary region asymmetry, respectively, and they were subcategorized. In Group IIA (8.2%), asymmetry was shown solely in the mandibular body region, and in Group IIB (18.4%), additional asymmetry was shown in the mandibular ramus region. Group IIIA (6.1%) showed asymmetry only in the maxillary region, and Group IIIB (22.4%) showed asymmetry in all 3 regions. CONCLUSION: The 3D-CT classification for facial asymmetry has the potential to replace the conventional cephalometric classification.

Case-Control Studies↗

PubMed2006

Effectiveness of dental computed tomography in diagnostic imaging of periradicular lesion of each root of a multirooted tooth: a case report.

Radiography by use of the three-dimensional (3D) Accuitomo XYZ Slice View Tomograph (3DX), a device for compact computed tomography in dentistry, was performed as a new diagnostic imaging technique for a patient who needed endodontic therapy. The 3DX was used for examining and diagnosing the presence and expansion of periradicular lesions in each root of a multirooted tooth. High-resolution 3D images were observed and compared with those obtained by routine conventional radiography. It was difficult to diagnose the cause of clinical symptoms by general examinations including the usual intraoral radiography and panoramic radiography. The images obtained by the 3DX, however, clearly showed the apparent presence and expansion of a periradicular lesion in only one root of the multirooted tooth. The 3DX, a newly developed dental computed tomography, provides abundant new image information not attainable by either intraoral radiography or panoramic radiography, and its application for clinical use is very effective for examining and diagnosing regions of interest for endodontic therapy.

Diagnosis, Computer-Assisted↗

PubMed2006

Dimensional accuracy of a binder jet model produced from computerized tomography data for dental implants.

A full-scale model produced by multislice helical computerized tomography (CT) was made by using the binder jet method and applied for presurgical diagnosis, surgical simulation, and the production of surgical templates for dental implant treatment. In this study, accuracy of the full-scale model with plaster powder was assessed by shifting the binary threshold values. A step phantom was made from bone-equivalent material. When it was placed in water, the CT imaging was performed with a multislice helical CT unit. Three-dimensional (3-D) images were reconstructed by 3-D visualization software. Using 4 different threshold values, full-scale models were produced by a binder jet method with plaster powder. All sides of the full-scale models were directly measured, and their values were compared with that of the step phantom. The mean difference was approximately 0.1 mm in the axial plane when the setting was 0.75 for the threshold. In total, the mean difference was approximately 0.2 mm when the setting was 0.50 for the threshold. It is suggested this full-scale model could be applied for presurgical diagnosis, surgical simulation, and the production of surgical templates in dental implant treatment.

Computer-Aided Design↗

PubMed2006

The role of objective plane angulation on the mandibular image using cross-sectional tomography.

Cross-sectional jaw images in the buccolingual direction obtained by conventional or computerized tomography are used in the image diagnosis of dental implant treatment. This study was performed to clarify the subjective image quality of the mandibular depiction by shifting the angles of the tomographic objective plane. A panoramic machine with a linear tomographic function was used to obtain cross-sectional tomographic images on bilateral first molar regions of 10 dried human mandibles. The angles of tomographic objective planes were shifted horizontally within a range of +/- 20 degrees at intervals of 5 degrees from the tomographic objective plane, which was automatically determined. The image qualities of 4 anatomical structures-alveolar crest, buccal and lingual cortical bone, and mandibular canal-were subjectively scored on a 5-point scale method. As a result, the permitted tomographic objective angles were from -1.7 degrees to 2.5 degrees, a range of 4.2 degrees for all 4 anatomical structures. When this result was compared with a previous geometric result, the permitted range of the angles was quite narrow. The tomographic objective angles should be manually set in accordance with an optimal tomographic plane for individual patients by using the positioning technique in linear tomography.

Alveolar Process↗

PubMed2005

Roots of the maxillary first and second molars in horizontal relation to alveolar cortical plates and maxillary sinus: computed tomography assessment for infection spread.

The purposes of this study were to investigate the horizontal relationship of the roots of maxillary molars with the cortical plates and the maxillary sinus and to investigate the influence of these relationships on the spread of odontogenic infection. Computed tomography images of 120 control subjects and 49 patients with infection originating in the maxillary first or second molar were investigated. In the control group, more than 60% of the first molar roots contacted both palatal and buccal cortical plates (type A), while such contact was not seen in more than 60% of second molars. The floor of maxillary sinus was most frequently observed at the level between the bifurcation and apices of roots in both first and second molars. In patients with infection, cortical changes were more frequently seen on the buccal side than on the palatal side, and 80% of patients with buccal cortical change showed the position in which the buccal roots were close to the buccal cortical plate. Mucosal thickening of the maxillary sinus was found in 87.8%. The buccopalatal spread of odontogenic infection originating in the maxillary first and second molars was influenced by the horizontal root position in relation to the cortices.

Adolescent↗

PubMed2005

Image artifact in dental cone-beam CT.

PURPOSE: The purpose of this study was to investigate the appearance and possible cause of an artifact seen in limited-volume cone-beam CT imaging. METHODS: A water-filled plastic cylinder was used as a phantom of the head. A test object was constructed as a bone-equivalent phantom to be imaged. The test object was variously positioned at the center of the phantom and near its margins. CT images of the test object were acquired using a 3DX Accuitomo system. RESULTS: In slice images with the test object positioned near the margin of the phantom, arch-shaped defects or deformities were observed on the side of the object. There was a negative correlation between the artifact and the CT value of the object. The artifact was larger in images scanned with a higher voltage. CONCLUSION: The probability that this artifact is caused by halation from the image intensifier (II) system is suggested.

Artifacts↗

PubMed2005

Condylar head remodeling following mandibular setback osteotomy for prognathism: a comparative study of different imaging modalities.

PURPOSE: Condylar remodeling, which develops after mandibular setback osteotomy, was evaluated and compared in CT, plain film radiographs, and MR images acquired postoperatively. METHODS: Thirty-nine patients treated with sagittal split ramus osteotomy (SSRO) and 46 patients treated with intraoral vertical ramus osteotomy (IVRO) were studied. Remodeling as seen in the images and the diagnostic agreement between imaging modalities was evaluated. RESULTS: A newly formed bone layer in the posterior part of the condylar head was identified as a sign suggestive of remodeling. This sign was seen predominantly at periods over 6 months postoperatively. IVRO subjects had a higher incidence of remodeling than did the SSRO group. The diagnostic agreement between the 3 imaging modalities was substantial. There was a positive correlation between postoperative condylar displacement and the incidence of remodeling. CONCLUSIONS: The incidence of postoperative condylar head remodeling may be predictable. High-dose postoperative imaging studies to assess the TMJ should be restricted to those cases having a clear need for such studies.

Adolescent↗

PubMed2005

Computed tomographic features of bilateral coronoid process hyperplasia with special emphasis on patients without interference between the process and the zygomatic bone.

OBJECTIVE: To reveal computed tomography (CT) features of patients with coronoid process hyperplasia without interference between the process and the zygomatic bone. STUDY DESIGN: A case-control study was designed. Thirteen cases without interference (2 male and 11 female, 28-56 years old) and 65 controls were sampled from a patient database. Differences in CT features were analyzed between the 2 groups regarding the following 7 points of 5 regions: configuration of the coronoid process, vertical level of the coronoid process, the distance between the bilateral zygomatic arches, thickness of the temporal muscle, anteroposterior width of the temporal muscle, thickness of the temporal muscle tendon, and thickness of the masseter muscle. Cluster analysis was applied to differentiate between individuals. RESULTS: All cases had bilateral hyperplastic change of the coronoid process. Differences were found between the cases and controls in 6 of 7 CT features with the exception of temporal muscle thickness. All incidences of significant difference showed larger values in the cases. All cases were clustered into the same group and were differentiated from the controls. CONCLUSION: CT features appeared to be effective for diagnosis of this condition, and these patients should be put into the same category under the diagnosis of coronoid process hyperplasia.

Adult↗

PubMed2005

3D-CT evaluation of facial asymmetry.

OBJECTIVE: Recently, 3-dimensional-computed tomography (3D-CT) imaging has been used in the diagnosis and surgical treatment planning of patients with craniofacial deformities. The present authors have developed a 3D-CT imaging procedure for a 3-dimensional coordinate point evaluation system to assess and diagnose patients with facial asymmetry. STUDY DESIGN: The CT data of 16 subjects was selected retrospectively as the control group from patients who had undergone CT examinations to diagnose conditions other than maxillofacial deformities. Anatomical landmarks modified from orthodontic craniometric (cephalometric) points were defined on the 3D-CT images and the asymmetry index of each point was calculated in millimeters. A diagrammatic chart with a baseline indicating the mean asymmetry indices plus the standard deviation in the control group was designed. The resulting diagrammatic chart was used to evaluate the degree of deformity in facial asymmetry patients. RESULTS AND CONCLUSIONS: The topography of facial asymmetry was assessed. The 3D-CT imaging technique as described herein is a practical method of evaluating the morphology of facial asymmetry.

Adolescent↗

PubMed2005

Can cephalometric indices and subjective evaluation be consistent for facial asymmetry?

The purpose of this study was to investigate the relationship between the subjective evaluation of facial asymmetry and seven cephalometric indices. Ten orthodontists subjectively evaluated the frontal photographs of 100 subjects and categorized them into three categories, ie, category I--symmetrical view; category II--a little asymmetry not requiring treatment; and category III--marked asymmetry requiring treatment. Seven indices that were used to evaluate facial asymmetry were determined using frontal cephalographs of these patients. Interobserver agreement was assessed using Cohen's kappa statistic. Agreement among the observers for category III was higher than for categories I and II. To define the characteristics of each category, the cephalometric indices, which at least eight observers agreed on, were compared between the categories. No differences were found in any of the indices between categories I and II. Five indices showed differences between category III and the other categories. Among them, the distance of Me from the vertical reference line was the most relevant index for the subjective evaluation of facial asymmetry. When a discrepancy is found between skeletal measurements and a subjective evaluation, the influence of soft tissue structures should be considered in facial asymmetry.

Adolescent↗

PubMed2005

Postoperative tomographic assessment of veneer bone grafting with implant placement in the maxillary anterior region.

Various ridge augmentation and sinus lift procedures were performed in severely resorbed alveolar crests of a maxilla to provide some volume for implant treatment. It was reported that the outcome of maxillary sinus lift procedures was evaluated with conventional tomography or computerized tomography, and that grafted bone around implants markedly progressed in resorption, particularly at the implant apex. However, veneer bone grafting with implant placement has not been evaluated after treatment with imaging techniques. Therefore, the purpose of this study was to assess veneer bone grafting after maxillary anterior implant treatment. Seven patients with a mean age of 24 years, with implants placed in the maxillary anterior region with or without autogenous veneer bone grafting were postoperatively examined using conventional tomography. On tomograms, the ratio of bone-to-implant contact and the area of bone were measured in labial bones with bone grafts, and they were compared with the values without bone grafts. In cases with bone grafting, the average ratio of bone-to-implant contact was 63.6%, whereas 81.8% was formed in cases without bone grafting. The average area of bone was 12.9 mm and 23.4 mm in patients with and without bone grafting, respectively. No significant difference was found between the implants with and without bone grafts. Resorbed labial bone was observed in the maxillary anterior region with and without veneer bone grafting.

Adolescent↗

PubMed2005

Assessment of three-dimensional X-ray images: reconstruction from conventional tomograms, compact computerized tomography images, and multislice helical computerized tomography images.

Three-dimensional X-ray images (3D images) were used for imaging diagnosis in the oral and maxillofacial region. These images could be fundamentally reconstructed from various tomograms, though clinical 3D images were mainly reconstructed from computerized tomography (CT) images. In this investigation, 3D images were reconstructed from conventional tomograms with a panoramic unit, compact CT images, and multislice helical CT images, and the usefulness of each system was subjectively assessed for dental implant treatment. Three hemilateral dried human mandibles were used and were examined by linear tomography with a panoramic unit, compact CT, and multislice helical CT, and 3D images were reconstructed by using the rendering software for each system. The 3D images were visually evaluated on a 5-point scale covering the alveolar ridge, buccal and lingual bone surface, mental foramen, and tooth sockets. As a result, 3D images reconstructed from conventional tomograms with the panoramic unit were assessed as fair to unsure, compact CT 3D images were assessed as unsure to good, and multislice helical CT 3D images were assessed as good to excellent. It was concluded that compact CT 3D images and multislice helical CT 3D images were useful in dental implant treatment.

Dental Implantation, Endosseous↗

PubMed2004

3D CT evaluation of masseter muscle morphology after setback osteotomy for mandibular prognathism.

OBJECTIVE: Following mandibular setback osteotomy, changes in the direction, length, and cross-sectional area of the masseter muscle were studied by means of computerized tomography (CT) images generated with a 3-dimensional (3D) reconstructive technique. STUDY DESIGN: Pre- and postoperative CT examinations were performed on 17 prognathic patients treated by sagittal split ramus osteotomy with rigid osteosynthesis and 13 patients treated by intraoral vertical ramus osteotomy without osteosynthesis. The pre- and postoperative masseter muscle direction and length were evaluated using 3D CT images observed from a lateral viewing angle. The cross-sectional area of the masseter muscle was first measured on an axial CT image of a selected slice level, following which the right-angle cross-sectional area of the muscle was revised using the measured area from the axial image. RESULTS: Postoperatively, anterior tilting of the masseter muscle was observed; however, masseter muscle length was unchanged. Three months postoperatively, a significant reduction in the cross-sectional area of the masseter muscle was seen. A tendency to revert back to the normal dimension was seen between 6 months and 1 year postoperatively. No significant difference was noted between the 2 surgical techniques. CONCLUSIONS: Three-dimensional computed tomography is an adequate imaging modality for masseter muscle evaluation. The results of this study suggest the masseter muscle may undergo reversible atrophy after mandibular setback osteotomy.

Adolescent↗

PubMed2004

Spread of odontogenic infection originating in the maxillary teeth: computerized tomographic assessment.

OBJECTIVE: The aim of this study was to investigate the pathways of infection originating in the maxillary teeth through the interpretation of computerized tomographic (CT) appearances. STUDY DESIGN: CT images of 78 patients were analyzed with reference to lateral asymmetry of shape and density of fascial spaces and tissues. RESULTS: Changes in the alveolar cortical plates were observed more frequently in the labial/buccal side than in the palatal side. The facial expression muscles were involved in 23 (19.4%) patients. Infection caused by anterior teeth often spread into the levator labii superioris and levator anguli oris muscles. Deep spread into the fascial space was found in 9 (11.5%) patients. Masticator space changes were predominantly seen in the patients with infection caused by molars. Maxillary sinus changes were found in 57 (71.3%) patients with infection originating in the canines, premolars and molars. CONCLUSION: Infection spread characteristics are related to the causal teeth, and the pathways were clearly demonstrated on CT images.

Adolescent↗

PubMed2004

Ultrasonographic features of the masseter muscle in female patients with temporomandibular disorder associated with myofascial pain.

OBJECTIVE: The purpose of the present study was to examine ultrasonographic appearances in female patients with temporomandibular disorder (TMD) associated with myofascial pain in comparison with healthy volunteers. STUDY DESIGN: The thickness of the masseter muscle in 25 female patients with TMD was measured at rest and at maximum contraction using ultrasonography. The visibility and width of the internal echogenic bands of the masseter muscle were also assessed and the muscle appearance was classified as 1 of 3 types: type I, characterized by the clear visibility of the fine bands; type II, thickening and weakened echo-intensity of the bands; type III, disappearance or reduction in number of the bands. RESULTS: There were significant differences in the thickness at rest and the increase ratio by contraction between the patient and control groups. The distribution of muscle types showed a significant difference between the 2 groups. CONCLUSION: The ultrasonographic features of the masseter muscle in TMD patients with myofascial pain were clarified and they might be related to muscle edema.

Adolescent↗

PubMed2004

Anatomical considerations for the spread of odontogenic infection originating from the pericoronitis of impacted mandibular third molar: computed tomographic analyses.

OBJECTIVES: The aims of the present study were to clarify the anatomy of impacted mandibular third molars in relation to surrounding structures and to investigate the pathway of infection originating from pericoronitis of this tooth. STUDY DESIGN: Computed tomography (CT) images were evaluated in 87 patients with uninfected mandibular third molar impaction and in 12 patients with infection originating from an impacted mandibular third molar. In uninfected patients, bony features around the impacted crown were investigated together with the relationship between the crown and surrounding muscles. In infected patients, involvements of bony and soft tissue structures were evaluated according to the disappearance of cortices and lateral asymmetry of density and shape in the spaces and muscles. RESULTS: In uninfected patients, the disappearance of the lingual cortical plate was observed in 48 (35.3%) impacted molars, while only in 11 (8.1%) teeth for buccal cortices. The cortical thickness was thinner on the lingual side than the buccal side. Sixty-five percent of the masseter muscle horizontally overlapped the crown, while almost all of the medial pterygoid muscle was posteriorly situated apart from the crown. The mylohyoid muscle horizontally overlapped the crown at below or intermediate vertical positions. In infected patients, the involvement of lingual structures was more frequently observed than that of buccal structures. The mylohyoid muscle was involved in 10 (83.3%) of 12 patients. Among them, 8 showed submandibular space involvement. CONCLUSION: CT findings supported the clinical observations of infection spread in patients with pericoronitis of the impacted mandibular third molar. CT appeared to be an effective tool for investigating the pathway of infection originating from the pericoronitis of impacted mandibular third molars.

Absorptiometry, Photon↗

PubMed2004

Measurement accuracy of reconstructed 2-D images obtained by multi-slice helical computed tomography.

The present dental reconstructed computed tomography (CT) images consist of continuously piled-up axial CT images that are perpendicular to the axial CT plane. In the mandibular posterior region, the angles of designed implants frequently differ from the angles perpendicular to the axial CT plane and the measurement of mandibular height is inaccurate. This study was performed to clarify the measurement accuracy of double-oblique reconstructed images in multi-slice helical CT, using dried mandibles. The mandibular height was measured from the alveolar crest immediately below the aluminum tube to the superior border of the mandibular canal using the double-oblique reconstructed images and the micro-CT average images of three semi-lateral dried mandibles. The mean of the differences between the double-oblique reconstructed images with a table pitch of 1.5 in a helical scan and the micro-CT average images was 0.31 mm. It is concluded that the accuracy of the double-oblique reconstructed image measurements with helical scan is high. So this double-oblique program can be applied to the imaging diagnosis in dental implant treatment.

Aluminum↗

PubMed2003

Stage I and II mobile tongue carcinomas treated by external radiation and gold seed implantation.

The purpose of this study was to analyze the influence of a protocol modification, in which the use of gold seeds was extended and elective neck irradiation was applied, on the treatment results of early carcinoma of the tongue. We analyzed 225 patients with Stage I (93 patients) and Stage II (132 patients) squamous cell carcinomas of the oral tongue. We compared the results between the two periods before (171 patients) and after (54 patients) the modification. The main alterations were the expanded use of gold seeds for tumors less than 5 mm in thickness and the application of elective irradiation for T2 tumors. The 5-year primary control and survival rates improved from 81% to 97% and from 81% to 93%, respectively. The occurrence of late complications-lingual muscle and mandibular bone necroses-was found not to deteriorate after the modification. We concluded that the modification was adequate.

Adolescent↗