Inferior alveolar nerve repositioning in the atrophic posterior mandibular alveolar ridge

Visibility of the mandibular canal and the mental foramen in panoramic radiography / 대한구강악안면방사선학회지

PURPOSE: To determine the head position that the superior border of the mandibular canal as well as mental foramen can be more clearly visualized in panoramic radiography MATERIALS AND METHODS: Ten dry mandibles were radiographed bilaterally using PM 2002 CC panoramic machine. A 20 mm thick aluminium filter was added to the slit collimator to obtain radiographs with acceptable density. The specimens were tilted by 2, 4, 6, 8, and 10 degrees downward with and without radiopaque markers. Radiopaque markers were inserted into the mandibular canals and the mental canals of each side of the specimens to serve as reference image when assessing the radiographs. The visibility of the mandibular canal and the mental foramen was estimated by 4 observers on all radiographs. The obtained results were analyzed statistically. RESULTS: Mandibular canals were significantly more clearly visible in the radiographs with 4 and 6 degree downward position on both sides (P<0.05). Mental foramens were significantly more clearly visible in the radiographs with 4, 6, and 8 degree downward on right side and 6 degree downward on left side (P<0.05). There was not significant difference between right and left sides. CONCLUSION: Panoramic radiographs with 4 to 6 degree downward tilting could be valuable in locating the mandibular canal as well as the mental foramen.

A study on the radiopacity of cavity lining materials for posterior composite resin restoration / 대한구강악안면방사선학회지

PURPOSE: The aim of this study was to determine the relative radiopacities of cavity lining materials (Resin-modified Glass Ionomer cement, Compomer and Flowable resin) for posterior composite resin restoration. MATERIAL AND METHODS: Resin-modified glass ionomer cement (Fuji II LC, Vitrebond(TM)), Compomers (Dyract , Compoglass, F2000, Dyract(R) flow Compoglass Flow) and Flowable resins (Tetric(R) flow, Aeliteflo(TM) Revolution(TM)) were used. Five specimens of 5mm in diameter and 2mm thick were fabricated with each material. Human molars were horizontally sectioned 2mm thick to include both enamel and dentin. The radiopacities of enamel, dentin, cavity lining materials, aluminum step wedge were obtainded from conventional radiograph and NIH image program. RESULTS: All the tested lining materials showed levels of radiopacity the same as or greater than that of dentin. All compomer tested (Dyract(R), Compoglass, F2000, Dyract(R) flow, Compoglass Flow) and Vitrebond(TM), Tetric(R) flow were more radiopaque than enamel. The radiopacities of Fuji II LC and Revolution(TM) were between enamel and dentin and resin-modified glass ionomer cement, Compomer and Tetric(R) flow were greater than those of Revolution(TM), Aeliteflo(TM) or dentin. The level of radiopacity of the tested materials was variable; those with low radiopacity should be avoided in class II restorations, where a clear determination of recurrent caries by the examining clinician could be compromised. CONCLUSON: Clinician should be able to distinguish these cavity lining materials radiographically from recurrent decay, voids, gaps, or other defects that lead to clinical failure. Utilization of materials ranked more radiopaque than enamel would enable clinicians to distinguish the lining material from tooth structure.

The Effect of Aloe, Gelfoam, Plaster on Bone Formation in applying to the bone defect / 대한구강악안면방사선학회지

PURPOSE: This study was to evaluate the effects of Aloe, Gelfoam, and Plaster of Paris on bone healing. MATERIALS AND METHODS: Four experimental defects were created for placement of the three materials in the right femur of dogs. One defect served as an empty control site. The evaluation was performed at 1-, 6-, and 12-weeks by light microscopy and NIH image program. RESULTS: Radiographic and Histologic examinations showed new bone formation in the presence of Aloe, Gelfoam, and Plaster of Paris and similar bone healing reactions. CONCLUSION: On the basis of these findings, it was concluded that Aloe, Gelfoam, and Plaster of Paris may be adequate agents for use in bone procurement.

A Comparative Study of Radiographic Images on Normal Anatomical Structures / 대한구강악안면방사선학회지

PURPOSE: To compare radiographic images of Digora system and Ektaspeed Plus film obtained from normal adults. MATERIALS AND METHODS: Storage phosphor plate(SPP) was placed in a film holder behind Ektaspeed Plus film package without lead foil. The effect of film on SPP was studied in a separate in vitro experiment. Forty-seven sets of images were prepared for the evaluaton. The regions of interest(ROI) for evaluation were designated at seven sites including normal anatomical structures. The image quality for each ROI was evaluated on enhanced and unenhanced storage phosphor(SP) images and Ektaspeed Plus film. RESULTS: Two film-SPP configurations showed significantly different grey levels at each step of the aluminum step wedge(p<0.05). The contrasts were comparable. Enhanced SP images were significantly superior to unenhaned images and film in all anatomical sturctures(p<0.01). The differences between unenhanced SP images and film were significant(p<0.05) except root canal and cortical bone on alveolar crest. For anatomical items, there were statistically significant difference among five observers(p<0.05). CONCLUSIONS: The image quality of enhanced SP images were superior to Ektaspeed Plus film, and Digora system is potentially applicable to clinical diagnosis.

A Study on the Diagnostic Detection Ability of the Artificial Proximal Caries by Digora(R) / 대한구강악안면방사선학회지

Digora system is an intraoral indirect digital radiography system utilizing storage phosphor image plate. It has wide dynamic range which allows it to decrease the patient's exposure time and may increase diagnostic ability through image processing (such as edge enhancement, grey scale conversion, brightness change, and contrast enhancement). And also, it can transmit and storage image information. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries between Conventional radiograph and Digora images(unenhanced image, brightness & contrast controlled image, and edge enhanced image). ROC(Receiver Operating Characteristic) analysis, paired t-tests, and F-tests were done for the statistical evaluation of detectability. The following results were acquired: 1. In Grade I lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.953, 0.933, 0.965, 0.978 (p>0.05). 2. In Grade II lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.969, 0.964, 0.988, 0.994. Among theses areas, there was just statistical significance between Diagnostic abilities of Digora edge enhanced image and Conventional radiograph(p<0.05). 3.In the Interobserver variability, the ROC curve areas of Digora edge enhanced image was lowerest in these areas, regardless of the Carious lesion depths. In conclusion, intraoral indirect digital system, Digora system, has the potential possibility as an alternative of Conventional radiograph in the diagnosis of proximal caries.

A Study on the radiosensitivity and chemosensitivity of YAC-1 Cell Line in Vitro / 대한구강악안면방사선학회지

The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chomotherapy . For this study, cell surviving curves were obtained for mouse lymphoma YAC-1 cell line using semiautomated MTT assay. 2, 4, 6, 8, 10Gy were irradiated at a dose rate of 210cGy/min using 60Co Irradiator ALDORADO 8. After irra diation, YAC-1 cell lines(3X10(4) cells/ml) were exposed to bleomycin or cisplatin for 1 hour. The viable cells were determined for each radiation dose and/or each concentration of drug at the 4th day. And they w ere compared to control values. The obtained results were as follows: 1. The surviving curve with gentle slope was obtained after irradiation of 2, 4, 6, 8, 10Gy on YAC-1 cell line. 2. The cytotoxicity of bleomycin or cisplatin was increased significantly at all concentration of 0.2microgram/ml, microgram/ml an d 20microgram/ml on YAC-1 cell line (P<0.01). 3. There were no significant differences of surviving fractions among 4Gy, 6Gy, and 8Gy after irradiation of each radia tion dose with 2microgram/ml of bleomycin compared with irradiation only on YAC-1 cell line(P<0.05). 5. There were significant differences of surviving fractions between the groups of irradiation only and the groups of i rradiation with 2microgram/ml of bleomycin or cisplatin at all doses of 2, 4, 6, 8 and 10Gy on YAC-1 cell line(P<0.05).