Technique of dental radiographic

education

1. Technique of Dental Radiographic Yashawant ku. Yadav B.MIT year Roll no. 06 NAMS -Bir Hospital   1

2. Overview Introduction Equipment's used Dental radiographic film type Anatomy of teeth Terminology Types of dental x ray References 2

3. Introduction Dental radiographs  are commonly called X-rays. Dentists use radiographs for many reasons to find hidden dental structures, malignant or benign masses, bone loss, and cavities. Dental caries, infections and other changes in the bone density, and the periodontal ligament, appear darker because X-rays readily penetrate these less dense structures. Dental restorations (fillings, crowns) may appear lighter or darker, depending on the density of the material. The dosage of X-ray radiation received by a dental patient is typically small (around 0.150 mSv for a full mouth series, according to the American Dental Association website).   3

4. Equipment's 4

5. Contd.. 5 X ray tube potential:- Not lower than 50kVp and recommended is 60-70kVp X-ray tube filtration: - 1.5mm aluminum equivalent for up to 70kVp and 2.5mm for more than 70kVp. X-ray beam dimensions:- Beam diameter at the patient’s skin not greater than 60mm. Minimum focus-to-skin distance:- 200mm for 60kVp or, grater and 100mm for less than 60kVp

6. Dental Radiographic Film Types There are two main types of dental x-rays intraoral (the x-ray film is inside the mouth) and extra oral (the x-ray film is outside the mouth). Intraoral x-rays are the most common type of x-ray. There are several types of intraoral x-rays. Each shows different aspects of teeth. 6

7. Dental radiographic film types:- Intra-oral radiography: – - direct or non-screen film -digital receptors. Extra-oral radiography: – - film-screen - digital receptors: (storage phosphor and solid-state). 7

8. Intra-oral film sizes:- Size 0 -22 *35mm: used for small children and anterior periapical using the paralleling technique. • Size 1 - 24 * 40mm: used for bitewings in small children and also for anterior projections in adults. Not available routinely in the our department . • Size 2 - 31 * 41mm: used for bitewings in adults and older (generally six years plus) children and periapical projections. Can be used for occlusal views in young children. • Size 4 -57 * 76mm: used for occlusal projections of the maxilla and mandible. 8

9. Dental digital receptors :- The two methods of image capture used are solid-state and storage phosphor: solid-state: These include charge-coupled device (CCD), charge-injection device (CID) and complementary metal oxide semiconductor (CMOS)based sensors. The sensor is linked directly to the computer via a cable. There is an instantaneous image display with these systems . storage phosphor: These systems are commonly found in general radiography departments and may be referred to as computed radiography (CR). Other terms used to describe the technique are photostimulable phosphor radiography (PPR), storage phosphor radiography (SPR) and photostimulable phosphor (PSP). The PSP imaging plates consist of europium activated barium fluorohalide . 9

10. Advantages and disadvantages of solid-state and storage phosphor 10 Advantages Disadvantages Almost instant images , negligible delay of 20s as the plate is read by the laser. Cost image manipulation In some solid-state systems, the sensor may have a smaller sensitive area than the film, requiring more exposures to the cover area of interest very wide exposure latitude sensors are identical in size and thickness to the film and are tolerated well by patients some imaging systems provide insubstantial intra-oral positioning devices .

11. Anatomy of Teeth 11 The anatomic crown of a tooth is the area covered in enamel above the cement enamel junction (CEJ) or "neck" of the tooth.  Most of the crown is composed of dentin with the pulp chamber inside.  The crown is within bone before eruption. After eruption, it is almost always visible. The anatomic root is found below the CEJ and is covered with cementum. As with the crown, dentin composes most of the root, which normally has pulp canals.

12. Contd.. A tooth may have multiple roots or just one root (single-rooted teeth). Canines and most premolars, except for maxillary first premolars, usually have one root. Maxillary first premolars and mandibular molars usually have two roots. Maxillary molars usually have three roots. Additional roots are referred to as supernumerary roots. 12

13. Dental formulae and notations - There are several internationally recognized methods of identifying the teeth that require radiography . The two most commonly used methods of notation are :- Palmer notation and • Fédération Dentaire International (FDI) notation. Deciduous teeth :-212/212 Permanent teeth:-2123/2123 13

14. Palmer notation 14 The Palmer notation is depicted schematically, with a vertical line between the central maxillary and mandibular incisors and a horizontal line between the maxilla and mandible, dividing the oral cavity into quadrants. The clinician requesting intraoral radiography uses these vertical and horizontal lines to denote the quadrant to which the tooth/teeth to be radiographed belong.

15. Contd.. To avoid confusion between the permanent and deciduous dentition, the following convention is observed:- For the deciduous dentition: five teeth in each quadrant are assigned the letters A–E, from the central deciduous incisor to the second deciduous molar, respectively. For the permanent dentition: Eight teeth in each quadrant are assigned the numbers 1–8, from the central incisor to the third permanent molar, respectively 15

16. Contd.. Examples of requests for dental examinations using this system are:- 16

17. Federation Denature International notation The dentition is again divided into four quadrants. These are assigned the numbers 1–4 for the permanent teeth and the numbers 5–8 for the deciduous dentition. In both dentitions, the quadrants follow on numerically, starting from the upper right, to the upper left, to the lower left and, finally, to the lower right. 17

18. Contd.. Examples of requests for dental examinations using this formula are: 53 – upper right deciduous canine. 37, 38 – lower left second and third molars. 18

19. Terminology Mesial :- represents that surface of the tooth adjacent to the median plane following the curvature of the dental arch. • Distal:- represents that surface of the tooth furthest away from the median plane following the curvature of the dental arch. • Lingual or palatal :- refers to the inner aspect of the teeth or dental arches adjacent to the tongue or palate, respectively. • Buccal or labial :- refers to the outer aspect of the teeth or dental arches adjacent to the cheeks or lips, respectively. • Occlusal:- refers to the biting surface of both premolar and molar teeth. • Incisal:- refers to the horizontal flat surface of the incisor teeth. 19

20. Contd.. Alveolar crest – Highest part of the alveolar bone. Alveolar ridge – Part of the bone that contains the tooth sockets Edentulous – Without teeth. Foramina – Plural for foramen; an opening. Interproximal – Between the teeth. palatal – The roof of the mouth. periapical – Surrounding the apex or tip of the tooth. periodontal – Surrounding the tooth. 20

21. Contd.. periodontal disease – Disease of the gums and supporting areas of the teeth. 21

22. Occlusal planes 22 The occlusal plane is the plane that passes through the opposing biting surfaces of the teeth. The terms upper occlusal plane and lower occlusal plane are used in radiographic positioning when carrying out intra-oral radiography.

23. Types of Dental Radiography Dental radiography is classified in to two types :- Bitewing Periapical Bitewing :- Bitewing radiography requires that the beam, in the horizontal plane, meets the teeth and the film at right-angles and passes through all the contact areas. 23

24. Indications For Bitewing Radiography The detection of dental caries in the upper and lower premolar and molar teeth • Monitoring the progression of dental caries • Assessment of existing restorations Assessment of the periodontal condition. To determine the relation of tooth to the occlusal plane for possibility if tooth ankylosis. To understand the configuration of pulp chamber. 24

25. Position of patient The correct film size is chosen and the bitewing tab is attached. Normally adult a size 2 film (31*41mm) ,And in children size 0 film (22*35mm) is used. Place the film in the lingual sulcus. • The anterior edge of the film should be located opposite to the distal aspect of the lower canine. • The tab rests on the occlusal surface of the lower teeth. • The patient is told to bite gently on the tab and, when the teeth are almost in contact, the operator pulls the tab laterally to ensure that there is good contact between the film and the teeth. 25

26. Contd.. 26

27. Direction and centering of the X-ray beam The tube is angled five to eight degrees downward (caudad) with the central ray at the level of the occlusal plane and perpendicular to the contact points of the teeth . Position of patient and film using a bitewing film-holding/beam-alignment instrument:- 27

28. Periapical radiography For periapical radiography, two techniques have been developed :- Bisecting angle technique : this is based upon the geometric theorem of isometry. It requires the central ray of the X-ray beam to pass through the root of the tooth at right-angles to a plane that is the bisector of the angle formed by the long axis of the tooth and the plane of the film. 28

29. Contd. Paralleling technique : this requires that the X-ray film is positioned parallel with the long axes of the teeth or tooth to be imaged. This enables the central ray of the X-ray beam to pass at right-angles, i.e. perpendicular, to the beam to the long axes of the teeth and the plane of the film. 29

30. Indications • Assessment of apical pathology and other lesions situated within alveolar bone. • Pre- and postoperative assessment of alveolar surgery. • Following trauma to teeth and alveolar bone. • Localization of teeth and presence/absence of teeth. • Before extraction to assess root morphology and the relationship of roots to vital structures, i.e. the inferior dental canal, the maxillary antrum. • During endodontic therapy(root canal therapy). • Pre- and postoperative assessment of implants. 30

31. Bisecting angle Technique 31

32. Contd.. 32

33. Bisecting angle technique (contd..) The convention for intra-oral film placement is as follows :- Anterior teeth (incisors and canines): long axis of film vertical. Posterior teeth (premolars and molars): long axis of film horizontal. Position of patient and film The patient’s head must be supported adequately with the medial plane vertical and the occlusal plane horizontal (i.e. upper occlusal plane and lower occlusal plane for maxillary and mandibular radiography, respectively). 33

34. Contd.. If a film holder is used If the patient’s finger is used: Position the film holder intra-orally adjacent to the lingual/palatal aspects of the tooth/teeth to be imaged Ensure that the tooth/teeth being examined are in the middle of the film Insert a cotton-wool roll between the opposing teeth and the bite block 2mm of the film packet should extend beyond the incisal or occlusal margin to ensure that the entire tooth is imaged Ask the patient to close together slowly to allow gradual accommodation of the film holder intra-orally. Instruct the patient to gently support the film using either their index finger or thumb. Tell the patient to continue biting on the bite block to position the film holder securely Apply the patient’s finger/thumb solely to the area of film that overlies the crown and gingival tissues of the teeth. 34

35. Direction and centering of the X-ray beam The X-ray beam should be centered vertically on the midpoint of the tooth to be examined. It is important to remember that proclined teeth will require more angulation, whilst retroclined teeth will need less angulation. • The X-ray tube must be positioned so that the beam is at right-angles to the labial or buccal surfaces of the teeth to prevent horizontal overlap 35

36. Imaging considerations 36

37. Contd.. 37

38. Paralleling technique The paralleling technique requires that the X-ray film is positioned parallel with the long axis of the teeth. The central ray of the X-ray beam passes at right-angles, i.e. perpendicular, to the tooth. In order to minimize magnification of the image and subsequent loss of image sharpness, the technique uses an increased focal spot-to-object distance, ensuring that a more parallel X-ray beam is incident to the object and image receptor. 38

39. Contd.. Advantages Disadvantages Minimal elongation/foreshortening/distortion The paralleling technique can be used when using X-ray equipment with a short FFD (less than 20cm) providing the operator accepts increased magnification Increased focus-to-skin distance (FSD) reduces surface dose Increased FSD improves image quality by reducing the penumbra effect Anatomical limitations, such as a shallow palate, principally in the maxillary molar and anterior regions, preclude true parallel placement of the film relative to the tooth. Reduction in distortion effects due to bending of the film/image receptor 39

40. Position of patient and film The appropriate film holder and periapical film are selected and assembled. Place the bite block in contact with the edge of the tooth to be imaged. Ensure that the film covers the particular tooth/teeth to be examined. Maxilla : – For the incisor, canine, premolar and molar regions, the film holder must be positioned some distance from the tooth to achieve parallelism. This requires using the entire horizontal length of the bite block with the film holder occupying the highest part of the palate. 40

41. Contd.. 41

42. Contd.. Mandible : – For the lower incisor teeth, position the film holder in the plane of an imaginary line intersecting the first mandibular premolars or as posterior as anatomy will allow. For the mandibular premolars and molars, position the film holder in the lingual sulcus adjacent to the teeth selected for imaging. 42

43. Direction and centering of the X-ray beam 43

44. Essential image characteristic There should be no evidence of bending of the teeth and the periapical region of interest on the image. • There should be no foreshortening or elongation of the teeth. • Ideally, there should be no horizontal overlap. If overlap is present, then it must not obscure the pulp/root canals. • The film should demonstrate all the tooth/teeth of interest (i.e. crown and root). • There should be 3mm of periapical bone visible to enable an assessment of apical anatomy. • There should be good density and adequate contrast between the enamel and dentine. • There should be no pressure marks on the film and no emulsion scratches 44

45. Third molar region Position of patient and film Surgical haemostats/needle holders can be used to stabilize the film. The upper leading anterior edge of a size 2 film is attached securely to the beaks of the needle holder, ensuring that the front aspect (or imaging surface) will face the X-ray tube when positioned intra-orally. The film is positioned in the lingual sulcus as far posteriorly as possible. The patient is instructed to hold the handles of the needle holder. 45

46. Direction and centering of the X-ray beam The tube is centered and angulated as outlined in the above table for the mandibular molar region. • The X-ray tube must be positioned so that the beam is at right-angles to the labial or buccal surfaces of the teeth to prevent horizontal overlap, and the film is exposed. 46

47. Contd.. 47

48. Occlusal radiography Occlusal projections are used to image relatively large areas of the dental arches True (Cross sectional/axial/plan) -Vertex Occlusal, Floor of mouth , -Mandible-Midline, Anterior, Posterior Oblique Maxilla- Anterior ,Midline, Posterior Mandible ,anterior Lower oblique 48

49. Indications -To localize accurately -Unerupted teeth, -Retained roots, -Odontomas(benign tumor of tooth development), -Foreign bodies, -Radio-opaque salivary calculi, etc. -To evaluate a patient with severe trismus or who cannot tolerate periapical radiography - To evaluate the medial-lateral extent of pathology, e.g. cysts, tumors, malignancy, osteodystrophy's 49

50. Vertex occlusal of the maxilla It requires the use of an intra-oral cassette with rare-earth intensifying screens to reduce the dose to the patient. This projection shows a plan view of the maxillary teeth and is used to demonstrate the Bucco-palatal relationship of unerupted teeth in the dental arch. 50

51. Position of patient and cassette The patient sits comfortably, with the head supported. The median plane is vertical and the occlusal plane is horizontal . The cassette should be placed flat in the patient’s mouth, adjacent to the occlusal surface of the lower teeth. Position the cassette as far back as possible, at least to the level of the first permanent molars. The patient should bite together gently to stabilize the cassette intra-orally. 51

52. Direction and centering of the X-ray beam The tube is positioned over the vertex of the skull, and the central ray is directed along the median plane downward (caudad) through the long axis of the upper central incisor teeth 52

53. True occlusal of the mandible (submental occlusal) This projection shows a plan view of the mandible, with the teeth and the lingual and buccal cortices seen in cross-section. Position of patient and film The occlusal film should be placed as far back in the mouth as the patient will tolerate, with the film resting on the occlusal surfaces of the lower teeth. The tube side of the film faces the floor of the mouth with the long axis of film extending across the oral cavity (i.e. perpendicular to the sagittal plane). 53

54. Contd.. The anterior leading edge of the film should extend 1 cm beyond the labial aspects of the mandible incisor teeth. • The patient is instructed to extend their head backwards so that the ala-tragus line is almost perpendicular to the floor. The head is then supported adequately in this position. • The patient should bite together gently to avoid pressure marks on the film. 54

55. Direction and centering of the X-ray beam • The tube is placed well down below the patient’s chin and directed vertically at 90 degrees to the occlusal plane and the film. • Centre the tube in the midline at 90 degrees to an imaginary line joining the first permanent molars (i.e. 3 cm distal to the midline of the chin). 55

56. Occlusal radiography additional views Oblique occlusal of the maxilla Midline occlusal Anterior oblique occlusal Posterior oblique occlusal 56

57. Oblique occlusal of the maxilla The projection is used to show the anterior maxilla. The tube is positioned above the patient in the midline and angled downwards (caudad) at 65–70 degrees, the central ray passing through the bridge of the nose towards the center of the film 57

58. Contd.. 58

59. Anterior oblique occlusal This projection is used to image the anterior region of the maxilla. The tube is centered over the lateral/canine region and is commonly Direction and centering of the X-ray beam • The centering point is the bridge of the nose with downward (caudal) angulation of 60 degrees. 59

60. Posterior oblique occlusal This projection demonstrates the posterior quadrant of the maxillary arch, the teeth, the alveolar bone and part of the maxillary antrum, the floor of the antrum and the zygomatic process of the maxilla superimposed over the roots and crowns of the molar teeth. Direction and centering of the X-ray beam The centering point is medial to the outer canthus of the eye but level with the pupil. It is important to ensure that the central ray is at right-angles to the dental arch. 60

61. lower oblique occlusal of the mandible This projection demonstrates the soft tissues of the middle and posterior aspects of the floor of the mouth. Direction and centering of the X-ray beam The X-ray tube is positioned 2 cm below and behind the angle of the mandible. 115 degrees cephalad 61

62. Alternative view of mandible oblique Head is rotated with the affected side 20 degrees away from the table. The X-ray tube is positioned above and tube position 25 degrees from the vertical. 62

63. EXTRA ORAL RADIOGRAPHY Lateral oblique of the body of the mandible and maxilla. Lateral oblique of the body of the mandible and maxilla (modification) of the projection. Lateral oblique of the ramus of the mandible. Lateral oblique of the ramus of the mandible(modification) of the projection. using wedge (10 degree),Using angle board. 63

64. Lateral oblique of the body of the mandible and maxilla. This projection shows the dentition in the premolar/molar region of the maxilla and mandible, the inferior cortex of the mandible, and the angle and ascending ramus of the mandible. 64

65. Direction and centering of the X-ray beam Direct the central ray at a point 2cm below and behind the angle of the contralateral side of the mandible (see figure). 65

66. Contd.. Positioning of the tube is dependent upon the area of clinical interest, i.e. The choice of beam angulation varies between 10 degrees upward and 10 degrees downward . • The central ray is perpendicular to the plane of the film. 66

67. Lateral oblique of the ramus of the mandible Direction and centering of the X-ray beam The central ray is directed posteriorly with upward angulation (cephalad) of 10 degrees towards the center of the ramus of the mandible on the side of interest. The centering position of the tube is the contralateral side of the mandible at a point 2cm below the inferior border in the region of the first/second permanent molar. 67

68. Contd.. 68

69. Dental panoramic tomography Rotational panoramic radiography, orthopantomography (OPT), dental panoramic tomography (DPT), panoral . Dental panoramic radiography is an extra-oral radiographic technique that produces an image of both jaws and their respective dentitions on a single film. 69

70. Indications Orthodontic assessment of the presence/absence of teeth • Detection and assessment of fractures of the mandible; •Assessment of large pathological lesions (e.g. cysts, tumors, osteodystrophy’s (A bone disorder that adversely affects bone growth). Assessment of third molars before surgical removal. 70

71. Principles of panoramic image formation Panoramic equipment is based upon a simultaneous rotational movement of the tube head and film cassette/carriage in equal but opposite directions around the patient’s head, which remains stationary. The technique employs a slit-collimated vertical X-ray beam, with an eight-degree upward inclination, in association with a similar collimation slit in front of the film cassette/carriage to receive the image. 71

72. References Clark’s 12 th edit web 72

73. Thank you for your kind Attention 73

74. Questions 1.Which of these teeth have two roots? a. Maxillary first premolars b. mandibular molars c. Bothe d. None 2. In Fédération Dentaries International notation P D 74 22 76

75. 3.How much angulation is preferred for upper canine . Caudally 30-35 Cranially 30-40 Cranially 45-50 Caudally 45-50 4. Exposure factor for dental radiography? a.40-50 kVp / 10-15 mAs b.50-60 kVp / 15-20 mAs c.60-70 kVp / 5-10 mAs d.60-80 kVp /7-10 mAs 75