This document discusses dental x-ray image characteristics including visual and geometric properties. Visual characteristics include density, contrast, while geometric characteristics are sharpness, magnification, and distortion. Density represents film darkening and is influenced by exposure factors and object thickness. Contrast is the difference in densities between regions and is influenced by subject contrast and kVp. Sharpness measures detail reproduction and is impacted by focal spot size and distances. Magnification increases with closer subject-film distance. Distortion alters shape and size from the film and teeth relationship or beam alignment. Proper interpretation involves localization, observation, general considerations and correlation of radiographic features.

1. Dental X-ray Image Characteristics Dr. Walid Samir Salem BDS, MS, MHPE lecturer, Oral Surgery Department Member, Dental education unit College of Dentistry, Qassim University

4. Magnification.

6. 0 RADIOPAQUE White to Light Gray Radiobaque 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. 0 The overall density of the film affects the diagnostic value of the film (ideal density, too light, too dark)

10. kV

11. Exposure time2. Object thickness 3. Object density 4. 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. FilmFog 0 Increased film density from causes other than exposure to the primary x-ray beam (scatter, improper safelighting, improper film storage, expired film) fog

14. 0 II) Contrast The difference in densities (blackness) between various regions on a radiograph

15. 0 High Contrast Short Scale Black and White (Few shades of gray) Best for caries detection

16. 0 Low Contrast Long Scale Many shades of gray Best for periapical or periodontal evaluation

17. Contrast influenced by: 0 Subject contrast 2. kVp 3. Film contrast

18. Subject contrast 0 Results from varying object densities within patient, this is determined by: thickness, density & composition of the subject

19. 0 kVp Affects energy (penetrating ability) of x-rays. 50 60 70 80 90 100 40

20. Film contrast: 0 It refers to the characteristics of the film that influence the radiographic contrast, it is incorporated into film by manufacturer.

21. FilmFog 0 Film 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 radiograph The larger the penumbra, the less sharp the image will be

24. Target (focal spot) Umbra Penumbra (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 sharpness Object Umbra Penumbra Target

27. Target Umbra Penumbra Increase source-object distance, increase sharpness Teeth film

28. Target Umbra Penumbra Decrease object-film distance, increase sharpness Teeth film film

29. Intensifying screens decrease sharpness 0

30. 0 Film crystal size The 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 sharpness 0

32. 0 II)Magnification Increase in size Magnification affected by: Source-object distance Object-film distance

33. Target 16” Magnification 0 Increase source-object distance, decrease magnification Target 16” Target 8” Decrease object-film distance, decrease magnification

34. 0 III) Distortion Change in the true shape or size of the object Distortion affected by: 1. Film-teeth relationship 2. Beam alignment

35. 0 Paralleling

36. 0 Bisecting angle

37. 0

38. 0 Ideal Radiograph Image same size as object Image same shape as object Image has good detail Image has good density and contrast

39. 0 Mandibular molar periapical film comes closest to satisfying properties of an ideal radiograph (either paralleling or bisecting)

41. Radiographic Interpretation basic Dr. Walid Samir Salem BDS, MS, MHPE lecturer, Oral Surgery Department Member, Dental education unit College of Dentistry, Qassim University

43. The difference between interpretation & diagnosis.

44. Rules of radiographic interpretation.

45. Image analysis.

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 interpretation The area to be examined must be completely shown at optimal angulations All 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.

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.

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 interpretation Localization. Observation. General consideration. Interpretation. Correlation.

57. Localization Localized or generalized Position in the jaw Single or multiple Size

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.

59. Upper left Lower left

60. Upper right premolar Lower anterior

62. Observation All 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 …………

64. Cervical burnout: usually appears as cervical RL and misinterpreted by caries; this occurs due to less density and more penetration of rays.

66. Bone Changes in bone may include: 1- Changes in density. 2- Changes in the margin 3- Changes inside the lesion. 4- Effect on surrounding tissues. 5- Changes in structure