Periapical radiograph

periapical radiograph

1. Periapical radiograph

2. DENTAL X-RAYS X-rays are produced by “boiling off” electrons from a filament (the cathode)and accelerating the el to the target at the anode. The accelerated x-rays are decelerated by the target material, resulting in bremsstrahlung .

3. History of X-Ray DISCOVEY Wilhelm Conrad Roentgen , Bavarian physicist, discovered the x-ray on 1895. In 1895 , German dentist Otto Walkhoff made the 1st dental radiograph. In 1895 , New York physician made the 1st dental radiograph in the united states using the skull.

4. Characteristics of x-rays •Invisible and undetectable by the senses. •No mass or weight. •No charge. •Travel at speed light. •Travel in straight line.

5. •Absorbed by matters. •Cause ionization. •Cause certain substances to fluoresce. •Can produce image on photographic film. •Cause changes in living cells.

6. Radiograph in dentistry X-rays in dentistry serves as the most important diagnostic tool. Radiograph in dentistry are divided into two: Intraoral radiograph. Extraoral radiograph.

7. Inrtaoral radiograph Intraoral X-rays are the most common type of X-ray It is used mainly for: > Detection of caries. >Check the health of the tooth root and bone surrounding the tooth. >Check the status of developing teeth. >Monitor the general health of your teeth and jawbone.

8. Types of intraoral radiograph Bite-wing X-rays  : Bite-wing X-rays are used to detect decay between teeth and changes in bone density caused by gum disease. Periapical X-rays : Periapical X-rays are used to detect any abnormalities of the root structure and surrounding bone structure. Occlusal X-rays  show full tooth development and placement

9. Extraoral radiograph Panoramic X-ray Tomograms  Cephalometric projections Sialography Computed tomography ,

10. General guidelines on patient care For intraoral radiography the patient should be positioned comfortably in the dental chair, ideally with the occlusal plane horizontal and parallel to the floor. Spectacles, dentures or orthodontic appliances should be removed. A protective lead thyroid collar should be placed. Intraoral film packets should be positioned carefully to avoid trauma to the soft tissues.

11. Indications of periapical radiography Detection of apical infection/inflammation Assessment of the periodontal statue After trauma to the teeth and associated A lveolar bone Assessment of the presence and position of U nerupted teeth

12. Assessment of root morphology before E xtractions During endodontics Preoperative assessment and postoperative A ppraisal of apical surgery Detailed evaluation of apical cysts and other lesions within the alveolar bone Evaluation of implants postoperatively

13. Ideal positioning requirements The desired tooth and film should be in contact or as close together as possible. The tooth and the film should be parallel to each other. The film packet should be place vertical for anterior teeth and horizontal for posterior and sufficient film space beyond the apices should be present. They tube head should be placed so the beam meets the tooth at right angle. The positioning should be reproducible.

14. Radiographic techniques • The paralleling technique • The bisected angle technique.

15. Paralleling technique The film packet is placed in a holder and positioned in the mouth parallel to the long axis of the tooth. The X-ray tubehead is then aimed at right angles (vertically and horizontally) to both the tooth and the film packet. To prevent the magnification (since the film are located at distance) a large focal spot to skin distance, by using a long spacer cone or beam-indicating device (BID) on the X-ray set.

16. A) a short cone and a diverging X-ray beam B) a long cone and a near-parallel X-ray beam.

17. Positioning techniques Selection of appropriate holder Incisor and canine - Anterior holder - Small film packet (22*35mm) Premolars and Molars – Posterior holder - large film packet ( 31*41mm) Smooth white surface of the film packet must face towards the x-ray tube head.

18. The patient is positioned with the head supported and with the occlusal plane horizontal. Packet film position Maxillary incisors and canines : positioned posterior to enable its height to be accommodated in the vault of the palate. Mandibular incisors and canines : positioned in the floor of the mouth, approximately in line with the lower canines or first premolars.

19. Maxillary premolars and molars : placed in the midline of the palate. Mandibular premolars and molars : placed in the lingual sulcus . The holder is rotated so that the teeth under investigation are touching the bite block. A cottonwool roll is placed on the reverse side of the bite block . This keeps the film and the tooth parallel .

20. The patient is requested to bite gently together. The locator ring is moved down the indicator rod until it is just in contact with the patient's face. The spacer cone or BID is aligned with the locator ring. This automatically sets the vertical and horizontal angles and centres the X-ray beam on the film packet. The exposure is made.

21. Bisected angle technique The film packet is placed as close to the tooth under investigation as possible without bending the packet. The angle formed between the long axis of the tooth and the long axis of the film packet is assessed and mentally bisected. The X-ray tubehead is positioned at right angles to this bisecting line with the central ray of the X-ray beam aimed through the tooth apex.

22. Using the geometrical principle of similar triangles, the actual length of the tooth in the mouth will be equal to the length of the image of the tooth on the film. Vertical angulation of the X-ray tubehead The angle formed by continuing the line of the central ray until it meets the occlusal plane determines the vertical angulation of the X-ray beam to the occlusal plane.

23. Horizontal angulation of the X-ray tubehead The central ray should be aimed through the interproximal contact areas, to avoid overlapping the teeth.

24. Positioning techniques Using film holders The film packet is pushed securely into the chosen holder. The X-ray tubehead is positioned. Exposure is made.

25. Advantages of the paralleling technique Geometrically accurate images are produced with little magnification. The shadow of the zygomatic buttress appears above the apices of the molar teeth. The periodontal bone levels are well represented. Periapical tissues shows minimal foreshortening or elongation. Crown of the teeth shows approximation of the caries.

26. The horizontal and vertical angulations of the X-ray tubehead are automatically determined by the positioning devices if placed correctly. The X-ray beam is aimed accurately at the centre of the film — all areas of the film are irradiated and there is no coning off or cone cutting. Reproducible radiographs are possible at different visits and with different operators.

27. Disadvantages of the paralleling technique Positioning of the film packet can be very uncomfortable for the patient, particularly for posterior teeth, often causing gagging. Positioning the holders within the mouth can be difficult for inexperienced operators. The anatomy of the mouth sometimes makes the technique impossible, e.g. a shallow, flat palate.

28. The apices of the teeth can sometimes appear very near the edge of the film. Positioning the holders in the lower third molar regions can be very difficult. The technique cannot be performed satisfactorily using a short focal spot to skin distance (i.e. a short spacer cone) because of the resultant magnification. The holders need to be autoclavable or disposable.

29. Advantages of the bisected angle technique Positioning of the film packet is reasonably comfortable for the patient in all areas of the mouth. Positioning is relatively simple and quick. If all angulations are assessed correctly, the image of the tooth will be the same length as the tooth itself and should be adequate (but not ideal) for most diagnostic purposes.

30. Disadvantages of the bisected angle technique The many variables involved in the technique often result in the image being badly distorted. Incorrect vertical angulation will result in foreshortening or elongation of the image. The periodontal bone levels are poorly shown. The shadow of the zygomatic buttress frequently overlies the roots of the upper molars. The horizontal and vertical angles have to be assessed for every patient and considerable skill is required.

31. It is not possible to obtain reproducible views. Coning off or cone cutting occur. Incorrect horizontal angulation will result in overlapping of the crowns and roots. The crowns of the teeth are often distorted, thus preventing the detection of approximal caries. The buccal roots of the maxillary premolars and molars are foreshortened.

32. Positioning difficulties Mandibular third molars . Gagging . Endodontics . Edentulous alveolar ridges . Children . Patients with disabilities .

33. Digital radiography Digital radiography  is a form of imaging x-ray where digital X-ray sensors are used instead of traditional photographic film. There are two major variants of digital image capture devices: flat panel detectors (FPDs) and high-density line-scan solid state detectors.

34.   Indirect FPDs . Amorphous silicon (a-Si) is the most common material of commercial FPDs. Amorphous silicon combines with caesium iodide( CsI ) or gadolinium oxysulfide  ( Gd 2 O 2 S), and converts X-rays to light.

35.   Direct FPDs . Amorphous selenium (a-Se) FPDs are known as “direct” detectors because X-ray photons are converted directly into charge.

36. High-density Line-scan Detectors A  high-density line-scan solid state detector  is composed of a photo stimulable barium fluorobromide doped with europium ( BaFBr:Eu ) or caesium bromide ( CsBr ) phosphor.

37. Advantage of digital radiography Elimination of chemical processing and associated errors. Reduction in radiation dose. Computer storage and archiving of patient information. Transfer of images electronically. Image enhancement and manipulation.

38. Disadvantage Cost Reduced resolution Quality of hard copy prints Image storage Image security Limited size of sensor available Lack of sensor flexibility Lack of training at both undergraduate and postgraduate levels.

39. Comparison of direct digital and conventional intraoral radiographs in detecting alveolar bone loss Background.  Intraoral  radiograph s are important diagnostic aids in periodontics . The authors conducted a study to compare estimates of bone levels from direct digital and conventional  radiograph ic under normal clinical use.

40. Methods.  A full-mouth series of conventional  radiograph s was taken for each of 25 subjects who had periodontitis . A long cone paralleling technique was used for periapical , or PA, images, and a paper sleeve with biting tab was employed for bitewing, or BW, images. A set of direct digital  radiograph s matching the conventional  radiograph s was taken for each subject under the same conditions.

41. Results.  Examiners measured 857 PA image sites and 315 BW image sites matched on both  radiograph ic systems. Paired  t  test showed significant differences in bone levels between the two systems. conventional PA images were higher in all maxillary sextants ( P  ≤ .02), and measurements from digital PA images were higher in mandibular anterior sextants ( P  = .007).

42. In digital BW images were higher in mandibular posterior sextants ( P  = .002) A χ 2  analysis of categorical bone levels (normal, early-to-moderate loss or advanced loss) showed significant differences between the imaging systems in revealing bone levels in both PA ( P < .04) and BW ( P  < .001) images. Digital  radiograph s showed a higher number of sites with bone loss than the conventional  radiograph s.

43. Conclusions.  Under normal clinical use, alveolar bone levels revealed on intraoral direct digital  radiograph s differ from those revealed on conventional radiograph s. Clinical Implications.  Intraoral direct digital  radiograph s are not an equivalent substitute for conventional  radiograph s in evaluating alveolar bone levels.