PURPOSE: We examined the effect of induced interocular difference of retinal illuminanace on stereopsis. METHODS: Fifty adults who have normal binocularity were examined with neutral density filters. The mean age was 29.1 years. While the monocular retinal illuminance was gradually reduced by increasing the value of neutral density filters, we measured the best corrected visual acuity and stereoacuity with Titmus test and Lang test. We used neutral density filter from 1.0 neutral density (ND, 10% transmit) to 3.0ND (0.1% transmit) with intervals of 0.2ND. RESULTS: The best corrected visual acuity began to decrease significantly when the value of neutral density filter reached 2.0ND (1% transmit). Stereoacuity also began to decline when the value was 1.4ND(4% transmit) with Titmus test and 1.6ND (2.5% transmit) with Lang test. CONCLUSIONS: Change of retinal illuminance effects more on stereoacuity than visual acuity as stereoacuity decreased earlier by increasing the value of density filters. These results imply that the stereopsis test could be more useful than visual acuity test for detecting ocular abnormalities influencing the retinal illuminance.
Adult ; Depth Perception* ; Humans ; Retinaldehyde* ; Telescopes* ; Visual Acuity

PURPOSE: The purpose of this study was to investigate the distribution and frequency of temporomandibular joint (TMJ) effusion in magnetic resonance (MR) images of patients with disc displacements. MATERIALS AND METHODS: On T2 weighted MR images of 148 TMJs taken from 74 patients presenting with TMJ pain and dysfunction, we assessed the cases showing TMJ effusion, defined as an amount of fluid that exceeded the maximum amount seen in a control group of asymptomatic volunteers. The amount of TMJ fluid was graded as: I (none or minimal), II (moderate), III (marked), and IV (extensive), according to a standard set by a reference. Disc displacement categories were also recorded. RESULTS: Of the 148 TMJs examined in this study, 52 joints (35.1%) presented with joint effusion, 24 (16.2%) showing bilateral joint effusion. 38 joints showed upper joint space effusion, 3 showed lower joint space effusion, and 11 showed both upper and lower joint space effusion. 96 joints (64.9%) had grade I joint fluid, 27 (18.2%) grade II, 15 (10.1%) grade III, and 10 (6.8%) grade IV. 80.0% of the joints presenting with grade IV effusion showed disc displacement without reduction. CONCLUSION: Joint effusion was found not only in upper, but also in lower joint spaces. The higher the effusion grade, the greater the frequency of disc displacement without reduction.
Humans ; Joints ; Magnetic Resonance Imaging* ; Temporomandibular Joint* ; Volunteers

PURPOSE: To evaluate the magnification error percentage in repeatedly taken panoramic radiographs of same patient and machine. MATERIALS AND METHODS: 92 panoramic radiographs from 46 patients were traced and 30 horizontal and vertical measurements were made with digital sliding caliper. The results were compared with paired t-test. RESULTS: There was no statistically significant difference between the two measurements. The overall difference as percentage error was 6.19+/-5.60%. The largest error as 14.61+/-12.44% was found at condylar height 1, and smallest as 1.86+/-1.61% at mandibular height. Overall vertical error excluding condylar height 1 was 3.76+/-3.97%, and the horizontal error 6.88+/-5.92%. CONCLUSION: Repeatedly taken panoramic radiographs of the same patient and machine was reliable since there was no significant percentage error difference but the percentage error ranged from 1.86+/-1.61% to 14.61+/-12.44% indicating the error depends on the measuring site.
Diagnostic Imaging ; Humans ; Radiography, Panoramic*

PURPOSE: To observe the relationship of bilaminar zone of temporomandibular joint retrodiscal tissues to the disc condition. MATERIALS AND METHODS: The upper and lower stratum of bilaminar zone were identified on magnetic resonance open mouth images of 148 joints from 74 patients with disc displacements. RESULTS: Both strata were identifiable in 105 joints which had disc displacement with reduction. Lower stratum was not identifiable in 35 joints which had disc displacement without reduction but 12 of 35 had hyalinized posterior attachment where the disc was. The 8 joints which had partial disc displacement without reduction showed identifiable lower stratum at the reducing site which was medial. CONCLUSION: Disruption or no identification of lower stratum which corresponds to the condylar portion of posterior attachment may be the sign of disc displacement without reduction.
Diagnostic Imaging ; Humans ; Hyalin ; Joints ; Magnetic Resonance Imaging ; Mouth ; Temporomandibular Joint Disorders ; Temporomandibular Joint*

PURPOSE: The purpose of this study was to present the clinical features of a case series of osteomas in the craniofacial region and to compare them with those described in the dental literatures. MATERIALS AND METHODS: A retrospective study of 18 patients diagnosed with osteomas in the craniofacial region was performed. The age, gender, location, symptoms, and the radiological findings were recorded. RESULTS: There were 13 women and 5 men from 18 years to 69 years of age (mean age, 42+/-27 years). Fourteen osteomas were found in the mandible (78%), two in frontal sinus, one in sphenoid bone, and one in maxilla. CONCLUSION: Osteomas are benign tumors composed of mature compact bone or cancellous bone. They are essentially restricted to the craniofacial skeleton and rarely, if ever, are diagnosed in other bones.
Female ; Frontal Sinus ; Humans ; Jaw ; Male ; Mandible ; Osteoma ; Paranasal Sinuses ; Retrospective Studies ; Skeleton ; Sphenoid Bone

In order to compare the accuracy of impression technique using the addition silicone putty and improved heavy body material, impression were taken for the natural 6 maxillary anterior teeth, and for the metal mast model that has full arch shape with 4 cylindrical abutment teeth, Marginal gingiva was retracted by routine method using retraction cord, and two techniques were tried to compare the length of impression materials in the gingival sulcus. This was aimed to see the effect of viscosity and hydraulic pressure of impression materials for the subgingival impression. Impressions for the full arch-shaped metal master model were taken to compare the linear stability of the different impression materials and their related techniques. The conclusions were as belows : 1. The one-step impression technique showed longer extension of impression material in gingival sulcus than two-step impression technique. 2. High viscosity and hydraulic pressure of impression material were useful to take subgingival impression. 3. There was no statistically significant difference for the two-dimensional accuracy of impression technique, but two-step technique showed better trend than one-step technique.
Gingiva ; Silicones ; Tooth ; Viscosity

PURPOSE: Disc and condylar position were observed on MRIs of temporomandibular joint disorder patients and condylar position agreement between MRI and tranascranal radiography was evaluated. MATERIALS AND METHODS: MRI and transcranial radiographs of both TM joints from 67 patients with temporomandibular disorder were used. On MRI, the position and shape of disc and condylar position as anterior, middle, posterior was evaluated at medial, center, and lateral views. On transcranial radiographs, condylar position was evaluated using the shortest distance from condyle to fossa in anterior, superior, and posterior directions. RESULTS: 1. On MRI, 96 joints (71.6%) of 134 had anterior disc dispalcement with reduction and 38 joints (28.4%) without reduction. 2. Fourteen (14.6%) of 96 reducible joints showed anterior condylar position, 19 (19.8%) showed central position, 63 joints (65.6%) showed posterior position. Two joints (5.3%) of 38 non-reducible joints showed anterior condylar position, while 9 (23.7%) showed central position, and 27 (71.1%)-posterior position. 3. In 85 joints (63.4%) of 134, the transcranial condylar position agreed with that of the central MRI view, 10 joints (7.5%) with that of medial, 16 joints (11.9%) with that of lateral, and 23 joints (17.2%) disagreed with that of MRI. CONCLUSION: On MRI, most of the reducible and non-reducible joints showed posterior condylar position. Transcranial radiographs taken with machine designed for TMJ had better agreement of condylar position with that of MRI. Extremely narrow joint spaces or very posterior condylar positons observed on transcranial radiographs had a little more than fifty percent agreement with those of MRIs.
Humans ; Joints ; Magnetic Resonance Imaging ; Mandibular Condyle ; Radiography ; Temporomandibular Joint Disorders* ; Temporomandibular Joint*

The author experienced 8 cases of pericoronal radiolucency involving an incomplete tooth crown that had not developed to form the cemento-enamel junction, and the underdeveloped crown sometimes appeared to be floating within the radiolucency radiographically. The first impression was that these cystic lesions had odontogenic keratocysts, but half of them turned out to be dentigerous cysts histopathologically. There has been no report concerning odontogenic cysts involving an incompletely developed crown. The purpose of this paper is to report that dentigerous cysts may develop before the completion of the cemento-enamel junction of a developing crown.
Crowns* ; Dentigerous Cyst ; Odontogenic Cysts ; Tooth Crown ; Tooth, Unerupted

PURPOSE: Upper cervical vertebrae are commonly imaged together with the jaw bones in panoramic radiography. There have been many studies investigating the possible role of mandible as an indicator of osteoporosis. But the result doesn't show unanimity. This study measured bone densities of mandible and second and third cervical vertebrae to find out any relationship between these two areas. These results may contribute in panorama being used as a screening method in detecting possible osteoporotic patient. MATERIALS AND METHODS: Randomly selected 226 digitized panoramic images with cervical vertebrae shadows from 156 dental patients between 5 to 80 years of age were used. And the bone densities of second and third cervical vertebrae, apical areas of first and second mandibular molars and interdental areas were measured. The bone density measurements were restricted to the cancellous bone and the average and standard deviations and paired t-tests were done to each measurements. RESULTS: All the measurements were statistically significantly related. The best relationship was found between the third cervical vertebrae and first and second mandibular apical areas. The average and standard deviations of the measured bone density ratios of these areas were 1.20+/-0.45 and 1.34+/-0.48 each. CONCLUSION: Patients whose panoramic bone density of the third cervical vertebrae are much below those of mandibular first or second molar apical areas may have osteoporosis.
Bone Density* ; Cervical Vertebrae* ; Female ; Humans ; Jaw ; Mandible* ; Mass Screening ; Molar ; Osteoporosis ; Radiography ; Radiography, Panoramic*

PURPOSE: To investigate and compare the prevalence, size, and location of maxillary sinus septa on panoramic and cone beam computed tomography (CBCT) images. MATERIALS AND METHODS: Two hundred patients who had taken both panoramic and CBCT images were included. The location of maxillary sinus septa on the panoramic radiographs were recorded and confirmed on the CBCT images. Also the size of septa was measured on the reformatted CBCT images. RESULTS: The prevalence of the patients who had maxillary sinus septa was 51.0% and they showed 179 septa totally. Among them 51.0% of the patients had one septum, 32.4% two septa, 13.7% three, and 2.9% four. The measured heights of the septa were 4.37+/-2.87 mm, 3.51+/-2.47 mm, and 3.04+/-2.37 mm in the medial, middle, and lateral areas, respectively. It was revealed that 1.0% was located at canine region, 18.0% at first premolar, 25.0% at second premolar, 22.7% at first molar, 19.8% at second molar, and 14.0% at third molar region. Among 213 septa depicted by the panoramic radiographs, only 69.0% were confirmed at the CBCT images. CONCLUSION: Since various heights and courses of the septa can develop in all parts of the maxillary sinus, adequate assessment of the inner aspect of the maxillary sinus is essential to avoid complications during sinus augmentation procedures. CBCT scanning is the preferred radiographic method for detecting the presence of sinus septa.
Bicuspid ; Cone-Beam Computed Tomography ; Humans ; Maxillary Sinus ; Molar ; Molar, Third ; Prevalence ; Radiography, Panoramic