STATEMENT OF PROBLEM: Initial stability of implant is an important factor for predicting osseointegration. It requires a rapid, non-invasive, user-friendly technique to frequently assess the implant stability and the degree of osseointegration. PURPOSE: The aim of this study was to evaluate the correlation between the resonance frequency analysis (RFA) and the radiographic method for peri-implant bone change under in vitro conditions. MATERIAL AND METHOD: Twenty implants of 3.75 mm in diameter(Neoplant, Neobiotech, Korea) were used. To simulate peri-implant bone change, 2 mm-deep 45degrees range horizontal defect and 2 mm-deep 90 degrees range horizontal defect area were serially prepared perpendicular to the X-ray beam after conventional implant insertion. Customized film holding device was fabricated to standardize the projection geometry for serial radiographs of implants and direct digital image was obtained. ISQ values and gray values inside threads were measured before and after periimplant bone defect preparation. Results. Within a limitation of this study, ISQ value of resonance frequency analysis was changed according to peri-implant bone change (p<0.05) and gray value of radiographic method was changed according to peri-implant bone change (p<0.05). There was no correlation between the ISQ value and the gray value for peri-implant bone change (p>0.05). But, in horizontal defect condition, relatively positive correlation were between ISQ and gray values(r=0.663). CONCLUSION: This results provided a possibility that peri-implant bone change may be evaluated by both RFA and radiographic method.
Dental Implants ; Osseointegration ; Radiography

The comparative detectability of the artificial periapical defects among Ektaspeed Plus film, digitized and digora images was evaluated. The artificail defects were made in the cancellous bone and cancellous-cortical junction with the size of 1.0x0.8mm2, 1.4x1.1mm2 and 2.8x2.2mm2. The defects in cancellous-cortical junction extended into cortical bone with the depth of 0, 0.5 and 1.0 mm. The results were as follows : 1. In junctional defects Ektaspeed Plus film for 2.8x12.2mm2 defect showed the highest detectability. But siginificant difference were only found between Ektaspeed Plus films and digitized images(p<0.05). 2. Almost all defects within cacellous bone were not detected except a few digitized and Digora images for the size of 2.8x2.2mm2. Digora images for them showed significant differences with Ektaspeed Plus films and digitized images(p<0.05). 3. The sensitinity of all imaging modalities were 0.9 or 1.0 in junctional defects for the size of 1.4x2.2mm2 and 2.8x2.2mm2. For cancellous defects, Digora image showed the highest sensitivity of 0.6 for the size of 2.8x2.2mm2. 4. Siginificant differences for change of exposure time were found in most group of Ektaspeed Plus films and digitized images(p<0.05). But there was no significant differences in Digora images for cacellous defects.
Radiography, Dental, Digital*

PURPOSE: To evaluate the effect of deviation of mandibular positioning, by changing the mandibular plane inclination, on the measured height and width of mandible in spiral conventional tomography. MATERIALS AND METHODS: By means of the Scanora multifunctional unit, cross-sectional tomograms were taken from two human dried mandibles at the mandibular angulations: -15 degrees, -10 degrees, -5 degrees, and 0 degree. Twenty-eight sites in two dried mandibles were imaged. One examiner measured the bone heights and widths at selected sites on the images and the actual bone heights were recorded. RESULTS: The bone heights at the four mandibular inclinations overestimated real bone heights and the mean difference between actual heights and image heights on 0 degree was the smallest (P< 0.01). The bone widths on -15 degrees were narrowest and there were significant differences between bone widths measured at the four mandibular inclinations (P< 0.001). We found statistically significant differences between both bone heights and widths as measured according to the mandibular plane angle for the posterior region (P< 0.01). CONCLUSION: The use of different mandibular positioning may result in discrepancies in heights and widths when measured from the cross-sectional tomographic images. It is suggested that the mandibular positioning may play a significant role in the measurement of mandibular heights and widths.
Dental Implants ; Humans ; Mandible ; Radiography, Dental, Digital

PURPOSE: To know whether there would be a difference among spiral tomograms of different slice thicknesses in the measurement of distances which are used for dental implant planning. MATERIALS AND METHODS: 10 dry mandibules and 40 metal balls are used to take total 120 Scanora tomograms with the slice thickness of 2 mm, 4 mm and 8 mm. 3 oral radiologists interpreted each tomogram to measure the distances from the mandibular canal to the alveoalr crest and buccal, lingual and inferior borders of mandible. 3 observers recorded grades of 0, 1 or 2 to evaluate the perceptibility of alveolar crest and the superior border of mandibular canal. For statistical analysis, ANOVA with repeated measure, Chi-square tests and intraclass correlation coefficient(R2, alpha) were used. RESULTS: There was not a statistically significant difference among spiral tomograms with different slice thicknesses in the measurement of the distances and in the perceptibility of alveolar crest and mandibular canal(p>0.05). All of them showed a good relationship in the reliability analysis. The perceptibility of alveolar crest and mandibular canal was almost similar and an excellent relationship was seen on all of them. CONCLUSIONS: There would be no significant difference, no matter which spiral tomogram of any slice thickness may be used in dental implant planning, considering the thickness of dental implant fixture.
Dental Implants* ; Mandible ; Radiography, Dental, Digital

PURPOSE: To evaluate the differences in bone height, bone width, and visibility of posterior spiral tomographic images according to various exposure directions, image layer thickness, and inclination of the mandibular inferior border. MATERIALS AND METHODS: Six partially and completely edentulous dry mandibles were radiographed using Scanora spiral tomography. Spiral tomography was performed at different exposure directions (dentotangential and maxillotangential projection), image layer thicknesses (2 mm, 4 mm and 8 mm), and at various inclinations to the mandibular border (+/-10, 0 and -10 ). The bone height and width was measured using selected tomographic images. The visibility of mandibular canal, crestal bone, and buccal and lingual surfaces were graded as 0, 1, or 2. RESULTS: The bone width at the maxillo-tangential projection was wider than at the dento-tangential projection (p< 0.05). The visibility of buccal and lingual surface at the maxillo-tangential projection was higher than at the dento-tangential projection (p< 0.05). Thinner image layer thicknesses resulted in greater visibility of buccal and lingual surfaces (p< 0.05). Bone height was greatest in the -10 group, and at the same time the bone width of the same group was the narrowest (p< 0.05). The visibility of alveolar crest and buccal surface of the+/-10 group was the highest, while the visibility of the mandibular canal was greatest in the 0 group. CONCLUSION: When spiral tomography is performed at the mandibular posterior portion for visualization prior to implant surgery, it is important that the inferior border of mandible be positioned as parallel as possible to the floor. A greater improvement of visibility can be achieved by maintaining a thin image layer thickness when performing spiral tomography.
Dental Implants ; Mandible* ; Radiography, Dental, Digital

The purpose of this study was to evaluate the accuracy and usefulness of spiral tomography through the comparison and analysis of SCANORA cross-sectional tomographs and DentaScan computed tomographic images of dry mandibles taken by a SCANORA spiral tomographic machine and a computed tomographic machine. Thirty-one dry mandibles with full or partial edentulous areas were used. To evaluate the possible effect of location in the edentulous area, it was divided into 4 regions of Me (region of mental foramen), M1 (the midportion between Me and M2), M2 (the midportion between mental foramen and mandibular foramen) and S (the midportion of the mandibular symphysis). A ZPC column (sized 4 mm X 5 mm) was seated on the edentulous regions of Me, M1, M2 and S using the acrylic stent. Then SCANORA spiral tomography and computed tomography were taken on the edentulous regions which contained the ZPC column. The ZPC columns and cross-sectional images of the mandible were measured in the radiographs by three observers and the differences between the two imaging modalities were analysed. The results were as follows: 1. In comparing the actual measurements of the ZPC column and measurements in the radiographs, the mean error of the DentaScan computed tomography was 0.07 mm in vertical direction and -0.06 mm in horizontal direction, while the mean error of the SCANORA spiral tomography was 0.06 mm in vertical direction and -0.12 mm in horizontal direction. There was a significant difference between the two radiographic techniques in the horizontal measurement of the ZPC column of the symphysis region (p<0.05). but there was no significant difference in the measurements of other regions>0.05). 2. In measurements of the distance from the alveolar crest to the inferior border of the mandible (H), and of the distance from the alveolar crest to the superior border of the mandibular canal (Y), there was no significant difference between the two radiographic techniques (p>0.05). 3. In measurements of the distance from the lingual border of the mandible to the buccal border of the mandible (W), and of the distance from the lingual border of the mandible to the lingual border of the mandibular canal (X), there was a significant difference between the two radiographic techniques in measurements of the midportion between the mental foramen and the mandibular foramen (M2) (p<0.05). but there were no significant differences in measurements of the other regions of symphysis>0.05). 4. Considering the mean range of measurements between observers, the measurements of SCANORA spiral tomography showed higher value than those of DentaScan computed tomography, except in measurements of symphysis (S). 5. On the detectability of the mandibular canal, there was no significant difference between the two radiographic techniques (p>0.05). In conclusion, SCANORA spiral tomography demonstrated a higher interobserver variance than that of DentaScan computed tomography for implant site measurements in the posterior edentulous area of the mandible. These differences were mainly the result of difficulty in the detection of the border of the mandible in SCANORA spiral tomography. But considering the cost and the radiation exposure, SCANORA spiral tomography can be said to be relatively good radiographic technique for implant site measurement.
Mandible* ; Radiography, Dental, Digital ; Stents

PURPOSE: To investigate the reproducibility of the conventional and digital radiographs to determine the depth of approximal root cavities. MATERIALS AND METHODS: A total of 80 artificial root cavities were prepared in the approximal surfaces of premolars, maxillary and mandibular molars. Standardized radiographs were taken at the baseline (0 horizontal and 0 vertical) and at a horizontal angulation of 10 in both mesial and distal directions. Radiographic cavity depths were measured by both conventional and digital radiographs. RESULTS: At 0 horizontal angulation, no statistically significant differences could be determined between the results of conventionally and digitally determined radiographic depths with respect to the actual cavity depths in all premolar, maxillary, and mandibular molar groups. All conventional and digital radiographic depths at both 10 mesial and distal angulations showed statistically significant increases in depth compared to the actual cavity depths (p< 0.05), with the exception of digital radiographic depth at 10 mesial angulation for premolars. There were no statistically significant differences between conventional and digital radiographic depths for all groups. CONCLUSION: The present study suggests that both conventional and digital radiographs provide reproducible assessment of the depth of the approximal root cavity. But horizontal X-ray beam movements are likely to result in increase in radiographic cavity depth.
Bicuspid ; Dental Caries ; Molar ; Radiography

PURPOSE: This study aimed to investigate the effect of changing the kilovoltage peak (kVp) on the radiographic assessment of dental caries. MATERIALS AND METHODS: Seventy-five extracted posterior teeth with proximal caries or apparently sound proximal surfaces were radiographed with conventional E-speed films and a photostimulable phosphor system using 60 kVp and 70 kVp for the caries assessment. The images were evaluated by three oral radiologists and compared with the results of the stereomicroscope analysis. RESULTS: No statistically significant difference was found between 60 kVp and 70 kVp for the caries detection, determination of caries extension into dentin, and caries severity in either the conventional or the digital images. Good to very good inter-observer and intra-observer agreements were found for both kilovoltage values on the conventional and digital images. CONCLUSION: Changing the kilovoltage between 60 kVp and 70 kVp had no obvious effect on the detection of proximal caries or determination of its extension or severity.
Dental Caries ; Dentin ; Diagnosis, Oral ; Radiography* ; Radiography, Dental ; Radiography, Dental, Digital ; Tooth

The scanora X-ray unit uses the principles of narrow beam radiography and spiral tomography. Starting with a panoramic overview as a scout image, multiple tomographic projection could be selected. This study evaluated the accuracy of spiral tomography in comparison to routine panoramic radiography for dental implant treatment planing. An experimental study was performed on a cadaver mandible to assess the accuracy of panoramic radiography and spiral tomography film images for measurement of metallic spheres. After radiographic images of the metallic spheres on the surgical stent were measured and corrected for a fixed magnification of radiographic images, following results were obtained. 1. In the optimal position of the mandible, the minimal horizontal and vertical distortion was evident in the panoramic radiography images. The mean horizontal and vertical magnification error in anterior sites was 5.25% and 0.75%, respectively. The mean horizontal and vertical magnification error in posterior sites was 0.50% and 1.50%, respectively. 2. In the displaced forward or in and eccentric position of the mandible, the magnification error of the panoramic radiography images increased significantly over the optimal position. Overall, the mean horizontal magnification error of the anterior site in the different position changed dramatically within a range of -17.25% to 39.00%, compared to the posterior range of -5.25% to 8.50%. However, the mean vertical magnification error stayed with the range of 0.5% to 3.75% for all the mandibular positions. 3. The magnification effects in the tomographic scans were nearly identical for the anterior and posterior with a range of 2.00% to 5.75% in the horizontal and 4.50% to 5.50% in the vertical dimension, respectively. 4. A statistically significant difference between the anterior and posterior measurements was found in the horizontal measurements of the panoramic radiography images of the displaced dorward and backward position of the mandiblw(P<0.05). also a significant difference between the optimal panoramic and tomographic projections was found only in the vertical measurement (P<0.05).
Cadaver ; Dental Implants ; Mandible ; Radiography ; Radiography, Dental, Digital ; Radiography, Panoramic ; Stents ; Vertical Dimension

PURPOSE: To evaluate the reliability of measurements in spiral tomography through assessing the visibility of the alveolar crest and the measurements between the alveolar crest and other anatomic structures. MATERIALS AND METHODS: 110 spiral tomograms of the jaws were taken by Scanora X-ray unit from the patients. The visibility of the alveolar crests was estimated by 3 observers and classified as clearly visible, questionable visibility, or not visible. 3 observers measured the distance between the alveolar crest and the reference points of anatomic structures. The measurements were repeated 2 weeks later. RESULTS: 52.9% of alveolar crests on upper jaws and 61.5% of alveolar crests on lower jaws were visible. The interobserver and intraobserver agreements on the visibility were low. The mean ranges of the measurements were 1.39 mm (SD = 1.37 mm) on maxilla and 1.03 mm (SD = 1.01 mm) on mandible in the interobserver evaluation. The interobserver variance was greater than the intraobserver variance in the measurements of distance. CONCLUSION: Spiral tomography showed a relatively low reliability in the visibility and measurements of the alveolar crest.
Dental Implants ; Humans ; Jaw ; Mandible ; Maxilla ; Radiography, Dental ; Radiography, Dental, Digital ; Tomography, X-Ray