Image Characteristic & Interpretation
- 1. Dental X-ray Image CharacteristicsDr. Walid Samir SalemBDS, MS, MHPElecturer, Oral Surgery DepartmentMember, Dental education unitCollege of Dentistry, Qassim University
- 2. Dental X-ray image characteristic include both visual & geomatric characteristics. Visual characteristic:Density.
- 5. Distortion.0RADIOLUCENTDark GraytoBlackA structure that lack density appear radiolucent e.g. soft tissue & spaces
- 6. 0RADIOPAQUEWhite to Light GrayRadiobaque structures are dense & absorb X-ray, e.g. enamel, dentine, & bone.
- 7. I) Density Represents the degree of darkening of an exposed x-ray film (white to black)
- 8. 0The overall density of the film affects the diagnostic value of the film (ideal density, too light, too dark)
- 9. Density influenced by:Exposure factors:mA
- 10. kV
- 11. Exposure time2. Object thickness3. Object density4. Film fog
- 12. Exposure factors (mA, kVp, exposure time). An unnecessary increase in any of these factors results in an increase in film density.Object thickness: the larger the patient’s head, the more x-rays that are needed to produce an ideal film density Object density: determined by type of material (metal, tooth structure, composite, etc.) and by amount of material
- 13. FilmFog0Increased film density from causes other than exposure to the primary x-ray beam (scatter, improper safelighting, improper film storage, expired film) fog
- 14. 0II) ContrastThe difference in densities (blackness) between various regions on a radiograph
- 15. 0High ContrastShort ScaleBlack and White(Few shades of gray)Best for caries detection
- 16. 0Low ContrastLong ScaleMany shades of grayBest for periapical or periodontal evaluation
- 17. Contrast influenced by:0Subject contrast2. kVp3. Film contrast
- 18. Subject contrast0Results from varying object densities within patient, this is determined by: thickness, density & composition of the subject
- 19. 0kVpAffects energy (penetrating ability) of x-rays.5060708090 10040
- 20. Film contrast:0It refers to the characteristics of the film that influence the radiographic contrast, it is incorporated into film by manufacturer.
- 21. FilmFog0Film fog makes the whole film darker, making it harder to see the density differences (contrast)fog
- 22. I) Sharpness Measures how well the details (boundaries/edges) of an object are reproduced on a radiograph.The fuzzy unclear area that surround the image is termed penumbra.
- 23. Penumbra (pene=almost + umbra= shadow)Def.: Zone of unsharpnessalong the edge of images in a radiographThe larger the penumbra, the less sharp the image will be
- 24. Target (focal spot) UmbraPenumbra(complete shadow)
- 25. Sharpness influenced by:Focal spot size Source–object (teeth) distance Object (teeth)-film distance Intensifying screens Film crystal size Motion
- 26. Decrease focal spot size, increase sharpnessObject Umbra PenumbraTarget
- 27. TargetUmbraPenumbraIncrease source-object distance, increase sharpnessTeethfilm
- 28. TargetUmbra PenumbraDecrease object-film distance, increase sharpnessTeethfilmfilm
- 29. Intensifying screens decrease sharpness0
- 30. 0Film crystal sizeThe faster film contain larger crystal size that produce less image sharpness, and vice versa.Unsharpness occur because the large crystals don’t produce object outline as well as smaller.
- 31. Patient motion decreases sharpness0
- 32. 0II)MagnificationIncrease in size Magnification affected by: Source-object distance Object-film distance
- 33. Target 16”Magnification 0Increase source-object distance, decrease magnificationTarget 16”Target 8”Decrease object-film distance, decrease magnification
- 34. 0III) DistortionChange in the true shape or size of the objectDistortion affected by: 1. Film-teeth relationship 2. Beam alignment
- 35. 0Paralleling
- 36. 0Bisecting angle
- 37. 0
- 38. 0 Ideal RadiographImage same size as objectImage same shape as objectImage has good detailImage has good density and contrast
- 39. 0Mandibular molar periapical film comes closest to satisfying properties of an ideal radiograph(either paralleling or bisecting)
- 41. Radiographic Interpretation basicDr. Walid Samir SalemBDS, MS, MHPElecturer, Oral Surgery DepartmentMember, Dental education unitCollege of Dentistry, Qassim University
- 42. Objectives:The importance of radiographic interpretation.
- 43. The difference between interpretation & diagnosis.
- 44. Rules of radiographic interpretation.
- 45. Image analysis.
- 46. Steps of interpretation.The importance of interpretation:Radiographic interpretation is an essential part of the diagnostic process. The ability to evaluate & recognize what is revealed by a radiograph enable us to detect diseases, lesions & conditions which can’t be identified clinically.
- 47. Interpretation Vs. Diagnosis:Interpretation refers to an explanation of what is viewed on a radiograph while diagnosis refers to the identification of disease by examination or analysis.In other words the interpretation is a step in the diagnosis.
- 48. Rules of radiographic interpretationThe area to be examined must be completely shown at optimal angulationsAll the boundaries of the area of interest must be shown with normal structures around it.Knowing and familiarity with all normal anatomical landmarks as well as all various pathological conditions that may affect the area of interest.Optimum viewing condition.
- 49. Viewing condition:Ideally, should include the following:Ambient light in the room should be reduced.
- 50. Intraoral radiographs should be mounted.
- 51. Light from the view-box should be of equal intensity across the viewing surface.
- 52. The size of the view-box should accommodate the size of the film.
- 53. A magnifying lens allows detailed examination of small regions of the film.0
- 54. 0
- 55. Image Analysis:The first step in image analysis is to use a systemic approach to identify all the normal anatomy present in an image.Avoid limiting your attention to one particular region of the film.
- 56. Steps of interpretationLocalization.Observation.General consideration.Interpretation.Correlation.
- 57. LocalizationLocalized or generalizedPosition in the jawSingle or multipleSize
- 58. How to identify the position of the periapical film?Embossed dot identify right from left and the anatomical land mark to identify the jaw and the area.
- 60. Upper right premolarLower anterior
- 62. ObservationAll shadows, other than the localized shadows of the normal landmarks must be observed.For example: shadows in crowns, cervical area, roots, restorations, size of root canals, periodontal membrane space, periapical area, alveolar crest, foreign bodies, integrity of bone …………
- 63. General considerationA radiograph shows only 2 dimensions of a 3 dimensional object (width and height but not the depth)
- 64. Cervical burnout: usually appears as cervical RL and misinterpreted by caries; this occurs due to less density and more penetration of rays.
- 65. Pulp exposure never to be determined from radiograph but only the proximity to the pulp. InterpretationStudying the features of teeth and bone:TeethStudy the whole tooth,(crown, root enamel, pulp….), number of teeth and finally supporting structures, (Periodontal membrane space, lamina dura, alveolar crest)
- 66. BoneChanges in bone may include:1- Changes in density.2- Changes in the margin3- Changes inside the lesion.4- Effect on surrounding tissues.5- Changes in structure
- 67. CorrelationThe final step is to correlate all of the radiographic features to reach a radiographic differential diagnosis.
- 68. Then to draw a final diagnosis, we have to correlate other data as case history, clinical examination, and other diagnostic aids with the radiographic differential diagnosis.0