Accuracy of artificial intelligence-assisted growth prediction in skeletal Class I preadolescent patients using serial lateral cephalograms for a 2-year growth interval.

OBJECTIVE: To investigate the accuracy of artificial intelligence-assisted growth prediction using a convolutional neural network (CNN) algorithm and longitudinal lateral cephalograms (Lat-cephs). MATERIALS AND METHODS: A total of 198 Japanese preadolescent children, who had skeletal Class I malocclusion and whose Lat-cephs were available at age 8 years (T0) and 10 years (T1), were allocated into the training, validation, and test phases (n = 161, n = 17, n = 20). Orthodontists and the CNN model identified 28 hard-tissue landmarks (HTL) and 19 soft-tissue landmarks (STL). The mean prediction error values were defined as 'excellent,' 'very good,' 'good,' 'acceptable,' and 'unsatisfactory' (criteria: 0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm, respectively). The degree of accurate prediction percentage (APP) was defined as 'very high,' 'high,' 'medium,' and 'low' (criteria: 90%, 70%, and 50%, respectively) according to the percentage of subjects that showed the error range within 1.5 mm. RESULTS: All HTLs showed acceptable-to-excellent mean PE values, while the STLs Pog', Gn', and Me' showed unsatisfactory values, and the rest showed good-to-acceptable values. Regarding the degree of APP, HTLs Ba, ramus posterior, Pm, Pog, B-point, Me, and mandibular first molar root apex exhibited low APPs. The STLs labrale superius, lower embrasure, lower lip, point of lower profile, B', Pog,' Gn' and Me' also exhibited low APPs. The remainder of HTLs and STLs showed medium-to-very high APPs. CONCLUSION: Despite the possibility of using the CNN model to predict growth, further studies are needed to improve the prediction accuracy in HTLs and STLs of the chin area.

Diagnostic value of MRI for odontogenic tumours.

OBJECTIVES: To evaluate the diagnostic value of MRI for odontogenic tumours. MATERIALS AND METHODS: 51 patients with odontogenic tumours were subjected to pre-operative MRI examinations. For tumours with liquid components, i.e. ameloblastomas and keratocystic odontogenic tumours (KCOTs), the signal intensity (SI) uniformity of their cystic components (UΣ) was calculated and then their UΣ values were compared. For tumours with solid components that had been examined using dynamic contrast-enhanced MRI (DCE-MRI), their CImax (maximum contrast index), Tmax (the time when CImax occurred), CIpeak (CImax × 0.90), Tpeak (the time when CIpeak occurred) and CI300 (i.e. the CI observed at 300 s after contrast medium injection) values were determined from CI curves. We then classified the odontogenic tumours according to their DCE-MRI parameters. RESULTS: Significant differences between the UΣ values of the ameloblastomas and KCOT were observed on T1 weighted images, T2 weighted images and short TI inversion recovery images. Depending on their DCE-MRI parameters, we classified the odontogenic tumours into the following five types: Type A, CIpeak > 2.0 and Tpeak < 200 s; Type B, CIpeak < 2.0 and Tpeak < 200 s; Type C, CI300 > 2.0 and Tmax < 600 s; Type D, CI300 > 2.0 and Tmax > 600 s; Type E, CI300 < 2.0 and Tmax > 600 s. CONCLUSION: Cystic component SI uniformity was found to be useful for differentiating between ameloblastomas and KCOT. However, the DCE-MRI parameters of odontogenic tumours, except for odontogenic fibromas and odontogenic myxomas, contributed little to their differential diagnosis.

Preliminary study evaluating the accuracy of MRI images on CBCT images in the field of orthodontics.

OBJECTIVE: The purpose of this study was to explore the 3-dimensional (3D) accuracy of magnetic resonance imaging (MRI) on cone-beam computed tomography (CBCT) images after the registration of MRI images on CBCT images. MATERIALS AND METHODS: Three Japanese adult females volunteered for this study. To transform digital imaging and communication in medicine (DICOM) data derived from MRI and CBCT images into polygon data, five software programs were used. CBCT and MRI images were obtained within one week, and both were registered by the iterative closest point (ICP) method. To assess the accuracy of the composite MRI-CBCT, the measurement errors of the MRI-CBCT were verified Measurement values were compared using frontal and cephalometric soft-tissue landmarks. Differences were analyzed using the non-parametric Mann-Whitney U test. RESULTS: There were no significant linear measurement errors (P > 0.05) when the images were measured from the superimposed MRI-CBCT images. CONCLUSION: The MRI images attained from MRI - CBCT registration showed accurate 3D linear measurements.

Manifestation of preferred chewing side for hard food on TMJ disc displacement side.

The purpose of this study was to reveal the relationship between chewing-side preference and anterior disc displacement (ADD) of the TMJ. Thirty-two healthy subjects with ages ranging from 26 to 34 years were selected from volunteer students at the Okayama University Dental School. Subjects were asked to chew freely with two kinds of test foods, beef jerky (hard food) and chiffon cake (soft food), thus expecting different amounts of mechanical loading on the TMJ. One, 4, and 7 s after starting the mastication, subjects were asked to open their mouth momentarily to have a digital image of their mouth taken. The bolus placement area was measured by processing the digital images, calculated as the number of pixel of bolus area. Area asymmetry index was used for the determination of preferred chewing side (PCS). Oblique sagittal MRI scanning in the closed mouth position was taken to evaluate the articular disc position. In asymptomatic subjects with ADD, a significant predominance of the PCS on the ipsilateral side of ADD was observed during the mastication of hard food. On the contrary, no correlation was found between unilateral ADD and PCS for the soft food. From the results of this study, it is suggested that ADD is the associating factor of PCS for hard food. Therefore, it would be necessary to break down the concept of PCS into at least two categories, one for hard food and one for soft food, considering the mechanical loading on the TMJ.

Measles virus receptors.

Measles virus (MV) has two envelope glycoproteins, the hemagglutinin (H) and fusion protein, which are responsible for attachment and membrane fusion, respectively. Signaling lymphocyte activation molecule (SLAM, also called CD150), a membrane glycoprotein expressed on immune cells, acts as the principal cellular receptor for MV, accounting for its lymphotropism and immunosuppressive nature. MV also infects polarized epithelial cells via an as yet unknown receptor molecule, thereby presumably facilitating transmission via aerosol droplets. Vaccine and laboratory-adapted strains of MV use ubiquitously expressed CD46 as an alternate receptor through amino acid substitutions in the H protein. The crystal structure of the H protein indicates that the putative binding sites for SLAM, CD46, and the epithelial cell receptor are strategically located in different positions of the H protein. Other molecules have also been implicated in MV infection, although their relevance remains to be determined. The identification of MV receptors has advanced our understanding of MV tropism and pathogenesis.

Evaluation of panoramic radiographs taken at the initial visit at a department of paediatric dentistry.

OBJECTIVES: To examine oral and maxillofacial lesions other than those related to the chief complaint in panoramic radiographs taken at the department of paediatric dentistry at our hospital. METHODS: We retrospectively reviewed all 1092 patients who had visited the department of paediatric dentistry at our hospital and had a panoramic radiograph taken between August 1999 and October 2004. The following information was obtained from the patients' files and panoramic radiographs: gender, age, chief complaints and the presence or absence of lesions. RESULTS: Lesions were observed in 140 of the 1092 panoramic radiographs (12.8%). Among the 140 patients discovered to have lesions in the panoramic radiographs, 66 (47.1%, or 6.05% of the entire group of 1092 patients) had different lesions from those underlying the chief complaint. These 66 patients ages ranged from 3 years to 14 years and the lesions involved 39 (59.1%) missing teeth, 20 (30.3%) mesiodentes, 4 supernumerary teeth, 1 odontoma, 1 radicular cyst and 1 impacted tooth. The missing teeth were observed in the central and lateral incisor, canine, and first and second premolar positions of both jaws, especially in the lower lateral incisor and upper central incisor positions. CONCLUSIONS: We were able to detect incidental lesions at a rate of 6.05% (66 of 1092 patients) and at a relatively early age (mean 6.8 years) in the present study. Early treatment of these lesions could avoid maxillofacial deformity and other complications.

Expression of immature and mature retinal cell markers in retinoblastoma.

AIM: To clarify the expression of immature and mature retinal cell makers in retinoblastoma cells and to give insights into the cell origin of the retinoblastoma. MATERIALS AND METHODS: Five samples from five eyes diagnosed with retinoblastomas were analysed by a standard immunohistochemistry using antibodies against Nestin and the hairy and enhancer of split mammalian homologue-1 (HES-1), both as markers for undifferentiated cells, and against Chx10, as a marker for both undifferentiated retinal cells and mature bipolar cells. Photoreceptor-specific nuclear receptor (PNR) was used as a postmitotic rod photoreceptor cell-specific marker, glial fibrillary acidic protein (GFAP) as a mature glia cell marker, and microtubule-associated protein (MAP) 2 as a mature neuronal cell marker. RESULTS: Nestin was detected in what were possibly Müller cells, but not in the tumour stroma. HES-1 was not detected in the retinoblastoma tissue. Chx10 was detected in one of the five samples. In this one sample, Chx10 expression was confined in a minor portion of the retinoblastoma cells. PNR was not detected in the retinoblastoma tissue. Expression of GFAP was detected only in the stromal cells of the tumour, which presumably represents reactive stromal astrocytes. In contrast, in all the samples, MAP2 was expressed in most of the retinoblastoma cells. CONCLUSIONS: The results of the current study support that retinoblastomas are derived from mature neural cells but do not originate from tumour stem cell(s).

Triamcinolone acetonide suppresses early proangiogenic response in retinal pigment epithelial cells after photodynamic therapy in vitro.

OBJECTIVE: To investigate the expression of proangiogenic and antiangiogenic factors, vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in retinal pigment epithelial (RPE) cells after photodynamic therapy (PDT), especially focusing on their change in the presence of triamcinolone acetonide. METHODS: Firstly, the cellular uptake of verteporfin was quantified after confluent ARPE-19 (human retinal pigment epithelial) cells were exposed to 5 microg/ml verteporfin combined with or without 1 microg/ml triamcinolone acetonide for 1 h. Secondly, ARPE-19 cells exposed to various doses of verteporfin were irradiated with 120 mJ/cm(2) light. After incubation with or without 1 microg/ml triamcinolone acetonide for 2 days, cell viability and expressions of VEGF and PEDF were assessed. RESULTS: Cellular uptake of verteporfin was not significantly changed by the presence of 1 microg/ml triamcinolone acetonide. In addition, 0.01-0.1 microg/ml of verteporfin showed a dose-dependent toxicity on the ARPE-19 cells 2 days after the light exposure. The presence of verteporfin at a concentration of 0.01 microg/ml did not affect the cell viability but significantly increased VEGF (p<0.001) and reduced PEDF (p = 0.03) expression. Administration of triamcinolone acetonide significantly suppressed both this increase in VEGF (p<0.001) and decrease in PEDF (p = 0.001). CONCLUSIONS: VEGF was increased and PEDF reduced in cultured RPE cells shortly after PDT even at a sublethal dose. Triamcinolone acetonide suppressed this proangiogenic response.

A case of recurrent ameloblastoma developing in an autogenous iliac bone graft 20 years after the initial treatment.

A case of recurrent ameloblastoma developing in an autogenous iliac bone graft 20 years after radical resection of primary mandibular ameloblastoma is presented. This case showed extensive bony resorption extending throughout the auto-grafted bone. Seeding to the graft bone was suspected as a cause of the recurrence in the iliac bone graft because wide destruction of the graft bone was observed without any prior signs and symptoms of intraoral mucosa. Consequently, extensive resection of bone as well as adjacent soft tissue was performed. Persistent follow-up examination is essential for management of ameloblastoma.

A2e mediated phototoxic effects of endoilluminators.

AIMS: To compare the theoretical retinal threshold time for endoilluminators and experimental phototoxic effect using A2e laden retinal pigment epithelial (RPE) cells. METHODS: The spectral irradiances of three types of 20 gauge and 25 gauge endoilluminators, currently commercially available from two manufacturers, were evaluated in conditions where the total beam spectral power was divided by the beam spot size at an estimated use distance of 5 mm from the retina. The retinal threshold time was calculated using the guidelines recommended by the International Commission on Non-Ionizing Radiation Protection. In vitro, A2e laden cells were evenly exposed to light for 30 minutes with a standard endoilluminator positioned 1 cm above the cells and the cell viability was assessed by WST-1 assay. RESULTS: The retinal threshold times were within 1 minute for all the endoilluminators tested. A significant decrease in the viability of A2e laden RPE cells was observed after they were exposed to light from two of the three 20 gauge endoilluminators. Cell viability was not affected by the exposure to 25 gauge endoilluminators under the same conditions. There was no correlation between the theoretical threshold times and experimental data. CONCLUSIONS: Light exposure during vitrectomy can induce photochemical damage to the retina. Although the A2e laden RPE model may not correctly mimic a clinical situation, this model may be useful to estimate the possible photochemical damage to RPE cells that could not be deduced by a theoretical retinal hazard model.

Bone deformity showing a deep coronoid notch of the mandible in a patient with neurofibromatosis type 1.

We present a case of a 10-year-old girl with neurofibromatosis type 1 related skeletal dysplasia. In the present case, a unilocular radiolucency at the left coronoid notch visible on a panoramic radiograph was suspected to be a neurofibroma. However, only the presence of bone deformities was observed on CT. Fat-like tissue adjacent to the bone deformities inside the left mandibular ramus was revealed, and the presence of neurofibroma was unequivocally denied on the MR images. However, biopsy of the lesion suggested neurofibroma. The diagnostic imaging 18 months after the first visit did not revealed a tumourous mass. However, careful follow up is required even though we could not prove the presence the lesion on the basis of imaging.

Retinal degeneration is delayed by tissue factor pathway inhibitor-2 in RCS rats and a sodium-iodate-induced model in rabbits.

PURPOSE: To investigate the in vivo effects of tissue factor pathway inhibitor 2 (TFPI-2), which stimulates proliferation of retinal pigment epithelial cells, but not the proliferation of fibroblast and vascular endothelial cells in vitro, on retinal degeneration using a sodium-iodate (SI)-induced model in rabbits and Royal Collage of Surgeons (RCS) rats. METHODS: 79 microg of recombinant TFPI-2 (rTFPI-2) or vehicle alone was injected intravitreously to 18 eyes of 12 pigmented rabbits a day after 20 mg/kg of SI was intravenously administered. Retinal function was assessed 4, 7, 14, and 21 days after the injection by analysing amplitudes of the c-wave of a bright flash electroretinogram. Additionally, 10 microg of rTFPI-2 or vehicle alone was injected intravitreously to 11 eyes of RCS rats at both 3 and 4 weeks old, then the retina was examined histologically at 5 weeks old. RESULTS: The rTFPI-2-treated eyes in rabbits showed a significantly less decrease in the relative amplitude of the c-wave than control eyes on days 4 and 7. The thickness of the outer nuclear layer was significantly thicker and the vacuole in the photoreceptor layer was less frequently observed in the rTFPI-2-treated RCS rats than the controls. CONCLUSIONS: Intravitreal injection of TFPI-2 rescues SI-induced retinal degeneration in rabbits and naturally occurring retinal degeneration in RCS rats at least partly. These results may suggest that this compound can be utilized in the treatment of retinal degeneration.

Radiographic examination of mesiodens and their associated complications.

OBJECTIVES: To examine mesiodens with regard to their status, their influence on adjacent teeth and their alteration during the follow-up period. METHODS: From retrospective reviews of all patients who visited our institution from 1990-2001, we identified 200 patients (256 mesiodentes) who were shown to have mesiodentes on the basis of a periapical radiograph, a panoramic radiograph or an axial radiograph. RESULTS: The number of supernumerary teeth was one in 146 cases (73%), two in 52 cases (26%) and three in 2 cases (1%). Of 256 mesiodentes, the direction of the crown of the mesiodens was inverted in 172 (67%), in a normal direction in 69 (27%) and in a horizontal direction with regard to the tooth axis in 15 (6%). Of the 147 mesiodentes for which axial radiography was performed, 131 (89%) were located at a palatal site against the dental arch, 16 (11%) overlapped the dental arch and none were at a labial site. Of our 200 cases, a delay of eruption of the permanent central incisor was seen in 12 (6%), malposition or rotation of the central incisor in 5 (2.5%) and dentigerous cyst formation arising from mesiodens in 22 (11%). Marked movement of the mesiodens was seen in 10 cases during the follow-up period of 5-7 years. Some complication arising from mesiodens was seen in 19.5% of all cases in our research. CONCLUSION: Although mesiodentes are not caused by malocclusion, they may cause it. A long period of impaction of mesiodentes may bring about dentigerous cyst formation or movement of the mesiodentes.

Radiographic examination of dentigerous cysts in the transitional dentition.

OBJECTIVES: To examine radiographically the relationship between the deciduous tooth and dentigerous cyst of the permanent successor during the transitional dentition. METHODS: From a retrospective review of all patients who visited our institution from April 1988 to August 2001, 70 patients under 16 years of age who had histologically confirmed dentigerous cysts that had developed from the central incisor to the second premolar were identified. These 70 patients were investigated using panoramic and periapical radiographs. RESULTS: In most cases (54 cases; 77.1%) the cyst was in the premolar region. Of the 54 premolars with dentigerous cysts, the overlying deciduous tooth had already been lost in 7 cases. Of the 47 remaining premolars with associated deciduous tooth, 35 (74.5%) had bone resorption of the periapical or bifurcation region, or irregular resorption of the associated deciduous tooth. Of the remaining 12 deciduous teeth with no periapical lesions, 9 had been treated with root canal therapy. Thus, 44 of these 47 cases (93.6%) had the possibility of inflammation at the deciduous tooth associated with the dentigerous cyst. Evidence from one case in the present study suggesting the process by which cyst development occurs is also given. CONCLUSION: Inflammatory change at the apex of the deciduous tooth may bring on a dentigerous cyst of the permanent successor.

Fluorescein angiography-guided indocyanine green angiography for the detection of feeder vessels in subfoveal choroidal neovascularization.

AIMS: To compare the newly devised fluorescein angiography (FA) - guided indocyanine green angiography (ICGA) with conventional ICGA for detecting feeder vessels in subfoveal choroidal neovascularization (CNV). METHODS: The detection of feeder vessels was attempted in 86 AMD patients with subfoveal CNV: 44 (age 70.4+/-4.5 years) underwent conventional ICGA (control group) and 42 (age 70.9+/-4.0 years) underwent an FA-guided ICGA (FA-guided group) using a double-detector scanning laser ophthalmoscope (SLO). In the control group, indocyanine green (ICG) was injected simultaneously with fluorescein. The patients were instructed to gaze forward localizing the fovea at the centre. In the FA-guided group, fluorescein sodium was injected a few minutes prior to ICG, and the patients were instructed to fixate in the appropriate direction by referring to the ongoing FA on the monitoring screen. In both groups, a 20 degrees visual angle was used to capture good images of feeder vessels in ICGA and, in case ICGA missed the first images of the entire CNV filling, an additional injection of ICG was given in the late phase to record the choroidal filling again. The overall detection rate, single-injection detection rate, double-injection rate and examination time were analysed using Fisher's direct exact probability test or Mann-Whitney's U-test. RESULTS: There was no significant difference in the overall detection of feeder vessels between the two groups (50% in the control group and 52.3% in the FA-guided group; P=0.49 with Fisher's direct exact probability test). However, in the FA-guided group, the single injection detection rate was significantly higher (45.1 and 15.9%, respectively; P<0.001 with Fisher's direct exact probability test); significantly less double injections were required (7.1 and 50%, respectively; P=0.003 with Fisher's direct exact probability test); and significantly shorter examination times were needed (9.6+/-3.7 and 14.1+/-6.8 min, respectively; P=0.02 with Mann-Whitney's U-test). CONCLUSION: FA-guided ICGA is effective for detecting feeder vessels of subfoveal CNV, minimizing the amount of ICG injected and the examination time compared to conventional ICGA.

Transpupillary thermotherapy for treatment of exudative age-related macular degeneration in Japanese patients.

PURPOSE: To report the therapeutic outcome of transpupillary thermotherapy (TTT) for subfoveal choroidal neovascularizarion (CNV) in brown retina using a diode-laser with the setting of lower energy level compared to the previous studies on light-pigmented Caucasian patients. METHODS: A total of 19 subfoveal CNVs in 18 patients were treated with TTT. The power of diode-laser was set 160 mW for 1.2 mm beam, 270 mW for 2.0 mm beam, and 400 mW for 3.0 mm beam, and the laser was delivered for 1 min through a slit-lamp mounted-delivery system. Patients were followed up for a mean of 8.8 months (4-12 months). Visual acuity and the fundus change as judged by funduscopic examination and simultaneous fluorescein and indocyanine green angiography were evaluated. Visual acuity was measured by a Japanese standard Landolt visual acuity chart and converted to logarithm of the minimal angle resolution (log MAR) visual acuity for statistical analysis. Improvement or decline in vision was defined as change of more than 0.2 in log MAR visual acuity. RESULTS: In eyes with minimally classic or occult only CNV, visual acuity improved in two eyes (18%) stabilized in seven eyes (64%) and worsened in two eyes (18%). In eyes with predominantly classic CNV, visual acuity improved in two eyes (25%), stabilized in four eyes (50%) and worsened in two eyes (25%). In all, 15 (84%) eyes of all studied subjects had improvement in exudation. Two (11%) and one (5%) eye(s) were noted to have a significant post-treatment haemorrhage and retinal pigment epithelial tear, respectively. CONCLUSION: In patients with brown retinal colour, the treatment outcome of TTT was comparable to that of light-pigmented Caucasian patients with approximately half the laser power energy. Further randomized control studies are warranted.

Comparison of radiographic and MRI features of a root-diverging odontogenic myxoma, with discussion of the differential diagnosis of lesions likely to move roots.

Lesions that can produce divergence of the roots of teeth in the mandible include odontogenic cysts (odontogenic keratocysts, lateral periodontal cysts and radicular cysts), ameloblastomas, odontogenic myxomas, central giant cell granulomas, adenomatoid odontogenic tumors and aneurismal bone cysts, and other tumors. Moreover most benign jaw lesions can do this occasionally. However, when lesions--which show interradicular tear-shaped radiolucencies--are small it is often difficult to interpret them radiographically, because they do not show characteristic radiographic features. We describe a comparison of radiographic and magnetic resonance (MR) features of a root-diverging odontogenic myxoma, with discussion of the differential diagnosis of lesions likely to move roots. In addition, we discuss radiographic and MR features of possible lesions, which show similar radiographic findings to odontogenic myxoma.