Chinami Igarashi

Tsurumi University, Yokohama, Kanagawa, Japan

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Publications (9)6 Total impact

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    ABSTRACT: Assessment of oral mucosal thickness is important in implant surgery; however, examining the soft tissue three dimensionally is difficult. A reamer method is invasive, and a non-invasive ultrasonic method produces only low-resolution images depending on anatomic variations. The emerging technology of spiral computed tomography (CT) is an alternative to the conventional methods. Spiral CT has been a useful diagnostic tool in implant surgery. Although it delivers high radiation doses, spiral CT provides three-dimensional imaging of low-contrast structures. The purpose of the present study is to assess the accuracy of oral mucosal measurements using spiral CT. Thickness of maxillary oral mucosa was measured in five cadavers. The measurement sites were set up in buccal, palatal, and middle of the crest in the missing tooth area in the incisor, canine, premolar, and molar regions. Each cadaver was exposed to spiral CT after installing the measurement guide. After that, each site was physically measured by reamer. Linear regression and correlation analysis were performed to describe the association between radiographic and physical measurements. A total of 114 measurements were performed with statistical analyses. Mean values and standard deviations of physical and radiographic measurements were 3.12 ± 1.43 and 2.83 ± 1.70 mm, respectively. The radiographic and physical measurements demonstrate strong correlation (r = 0.90; P <0.01). Measurement error was 0.52 ± 0.36 mm. According to the regions, the measurements in buccal, palatal, and missing tooth region depicted a significant correlation (r = 0.92, r = 0.85, and r = 0.91, respectively). The boundary of the bone and mucosa was indistinguishable at 23 buccal sites. Twenty-three measurements that could not be distinguished with CT had a mean of 0.69 and standard deviation ± 0.13 mm. The correlation between spiral CT and physical measurement was high except in sites of very thin mucosa. Spiral CT can be considered an alternative method for the measurement of oral mucosal thickness. Because of the higher radiation exposure, caution should be exercised and radiation dosage versus clinical benefit assessment is required.
    Journal of Periodontology 11/2010; 82(6):829-36. · 2.40 Impact Factor
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    ABSTRACT: The accuracies of intraoral radiography (IOR), multidetector helical computerized tomography (MDHCT) at slice thicknesses 0.63 mm and 1.25 mm, and limited cone-beam computerized tomography (LCBCT) were compared for detection of horizontal tooth root fracture. In 7 beagle dogs, 28 maxillary anterior teeth were used, of which 13 had artificially induced horizontal root fracture. The specimens were examined by the above-mentioned 4 modalities. Diagnosis of root fracture was based on direct visualization of radiolucent line in each image by 6 radiologists. Sensitivity, negative predictive value, and diagnostic accuracy (true positives + true negatives) for detecting fracture lines in LCBCT (0.96 +/- 0.04, 0.97 +/- 0.03, 0.93 +/- 0.04, respectively) were significantly higher than MDHCT at 0.63 mm (0.76 +/- 0.09, 0.8 +/- 0.05, 0.8 +/- 0.05, respectively), MDHCT at 1.25 mm (0.49 +/- 0.09, 0.66 +/- 0.04, 0.69 +/- 0.05, respectively), and IOR (0.51 +/- 0.18, 0.67 +/- 0.08, 0.69 +/- 0.08, respectively). Specificity and positive predictive value showed no significant intermethod difference among the 4 modalities. Limited cone-beam CT is more useful than the other 3 radiographic modalities for diagnostic imaging of horizontal tooth root fracture.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 11/2009; 108(5):e70-4. · 1.50 Impact Factor
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    ABSTRACT: ObjectivesAn insufficient knowledge of anatomy often complicates the interpretation of radiological findings by students learning clinical medicine. During a 3-week clinical course in oral radiology, students attended lectures on anatomy for half of each day. Our objectives were to evaluate this program and determine why some students remained unmotivated to learn anatomy. MethodsSurveys were carried out using two questionnaires, one for evaluating the students’ beliefs regarding the necessity of knowing anatomy and their understanding of radiology and anatomy, and the other for determining the value of the educational program. In total, 126 questionnaires were analyzed. Structural equation modeling and decision analysis were used to analyze the data obtained. ResultsBeliefs regarding the necessity of knowing anatomy were explained by three variables: the necessity of knowing imaging anatomy, the necessity of knowing gross anatomy, and understanding of anatomy. Awareness of the necessity of knowing anatomy and understanding of graphical images were not strongly correlated. The educational program was characterized by two factors: “value” and “appropriateness” These were strongly correlated. Student interest in the content of the course was found to be the most important factor in student evaluations of the educational program. Students who answered “agree”, “disagree” or “strongly disagree” to three items, “interested in the content of the course”, “obtained knowledge through the course” and “expected the course to be useful in the near future” were likely to have insufficient understanding of and awareness of the necessity of radiology and anatomy. ConclusionsThe inclusion of lectures on anatomy is beneficial for improving student understanding of oral radiology. Student interest in the content is important in evaluations of radiology–anatomy programs.
    Oral Radiology 11/2007; 23(2):26-33. · 0.17 Impact Factor
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    ABSTRACT: Double mental foramina found with preoperative computed tomography (CT) prior to implant therapy are reported and discussed in reference to literature reports. A 52-year-old man visited us for implant therapy. Preoperative panoramic radiography and CT were conducted. A multisection reconstructed sagittal image showed two mental foramina leading to the mandibular canal on the right side of the mandible, which were diagnosed as double mental foramina. The incidence of double mental foramina reported in the literature is approximately 6.9% in dry Japanese skulls. Many reports have indicated that non-Caucasians have a higher incidence than Caucasians. The general incidence ranges from 2% to 10%. However, only one clinical case report is available.
    Oral Radiology 11/2004; 20(2):68-71. · 0.17 Impact Factor
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    ABSTRACT: ObjectiveThe purpose of this study was to estimate the inter- and intraobserver agreement for interpreting magnetic resonance (MR) images of the temporomandibular joint (TMJ).MethodsThe study was based on MR images of 30 TMJs. The images were interpreted by seven observers for disk configuration, disk position, joint fluid, bone marrow changes, and diagnosis. The observers were not calibrated. Kappa statistics were used.ResultsThe kappa values were, for interobserver agreement of disk configuration, 0.10; for disk position in the sagittal plane with closed mouth, 0.35; for a combination of closed mouth and open mouth, 0.44; for disk position in the coronal plane, 0.17; for joint fluid, 0.36; for bone marrow changes, 0.01; and for diagnosis, 0.39. Intraobserver agreement was generally higher than interobserver agreement.ConclusionAgreement on disk position in the sagittal plane, on presence and amount of joint fluid, and on diagnosis was fair to moderate. Agreement on disk configuration, on disk position in the coronal plane, and on bone marrow changes was poor.
    Oral Radiology 01/2004; 20(2):62-67. · 0.17 Impact Factor
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    ABSTRACT: The purpose of this study was to clarify the CT features of odontogenic myxoma. CT appearances were analysed in 17 patients with histologically verified odontogenic myxoma collected from five dental hospitals in Japan. On the CT images, tumour borders were generally well defined with a smooth margin both for bony and soft tissue structures in all patients. Cortical status was clearly evaluated using CT and the continuity was interrupted in nine patients. Intralesional trabeculations were observed in 13 patients. Of these 13, 6 patients showed the characteristic appearance of angular or straight trabeculations within the tumour. The trabeculations were frequently observed at the peripheral portion of the tumour. In three maxillary tumours, soft tissue margins were observed beyond the cortical margin and/or intralesional trabeculations. In 10 of the 13 lesions evaluated, the majority of the whole tumour area showed relatively lower density compared with surrounding muscles. CT clearly demonstrated characteristic features of odontogenic myxoma. CT analysis may contribute to establishing a consensus regarding the interpretation of conventional radiographic appearances in odontogenic myxoma.
    Dentomaxillofacial Radiology 06/2003; 32(3):160-5. · 1.27 Impact Factor
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    ABSTRACT: The aim of our study was to find symptomatic diagnostic factors for sideways displacement of the temporomandibular joint disc, compared with anterior or rotational disc displacement. A consecutive series of 2310 temporomandibular joints were examined with MRI to define the clinical signs and symptoms particularly related to sideways disc displacement compared to anterior disc displacement with logistic regression model. Bone change of the mandibular condyle and age were negatively related factors in differentiating cases with lateral disc displacement from anterior disc displacement without reduction. Range of mouth opening (over 40 mm) was a significant predictor (odds ratio 4.5865 for lateral disc displacement). This study suggested the wide opening of the mouth to become the predictor for the lateral disc displacement among the cases suspected to have disc displacement without reduction.
    Journal of medical and dental sciences 10/2002; 49(3):89-94.
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    ABSTRACT: Without Abstract
    Oral Radiology 05/1999; 15(1):61-71. · 0.17 Impact Factor
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    ABSTRACT: ObjectivesThis 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. MethodsThe 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. ResultsThe robot was safe in the phase-1 trial, except for two massages in which the pressure was excessive. Massages at 6–10N were given the highest VAS scores. In phase 2, the massage pressure was arbitrary and each muscle was massaged seven times for 1min, 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. ConclusionThe massage treatment was safe and effective for most patients when administered at a pressure of 6–10N seven times for 1min per muscle every two weeks. The robot may constitute a useful tool for treating TMJ dysfunction associated with myofascial pain.
    Oral Radiology 25(1):53-59. · 0.17 Impact Factor