Intraoral radiographic techniques

1. Intraoral radiographic techniques

2. 3 types intraoral projections - Periapical - Bitewing - occlusal

3. Periapical Peri – around Apical - apex - Periapical radiographs record Images of outlines, position, mesio distal extent of teeth & surrounding tissues - obtain atleast 2mm periapical bone

4. Head position • - Patient’s head should be in upright position • - Occlusal plane of teeth parallel to floor • - Saggital plane of head perpendicular to floor • Ala tragus line should be parallel – maxillary teeth • Head tilted slightly backward so occlusal plane of • mandible parallel to floor when mouth opened • Chair raised or lowered so patient’s mouth is • about level with operator’s elbow

5. X- ray beam angulation - Vertical - horizontal • - Vertical angulation is movement of tubehead • up & down In relation to occlusal plane • which is parallel to floor • Measured in degrees • Downward angulation of cone is positive • Upward angulation of cone is negative

6. Horizontal angulation is the movement of x-ray tube head around patient’s head in relation to saggital plane when patient is in upright position It should be directed through contacts of the teeth & perpendicular to horizontal plane of the film Improper horizontal angulation will cause overlapping of tooth images

9. Film holder’s • - Rinn XCP or dentsply instruments • Masel precision rectangular collimating • instruments • - Stable disposable film holder • Snap -A –ray film holder • Hemostat with bite bloch

11. Paralleling or right angle technique • - film is placed in mouth in a position that is parallel • to long axis of the teeth • central ray of the x-ray beam is directed • perpendicular or at right angles to both the long • axis of teeth & plane of the film • - To achieve parallelism object film distance have • to be increased • Source film distance has to be increased • ie16 inches is most practical [long cone tech]

18. Advantages • Accuracy: • produces an image that has dimensional accuracy • image is representative of actual tooth, • free of distortion • Exhibits maximum detail & definition • Simplicity: • simple & easy to learn • vertical & horizontal angulation need not determined • since film holder with beam alignment device is used • Duplication: • Easy to standardised & accurately duplicated

19. Disadvantages • Film placement: • In child or adult patient with small • or shallow mouth • Discomfort • Film holding device used may impinge on • oral soft tissues

20. Bisecting angle technique principle Based on geometric theorem – Cieszynski’s Rule of isometry i.e. 2 triangles are equal when They share one complete side & have 2 equal angles

21. method Position the film as close as possible to lingual Surface of teeth, resting in palate or floor of mouth Plane of film & long axis of teeth form an angle with its apex at point where film is in contact with the teeth Construct an imaginary line that bisects this angle & direct the central ray of beam at right angles to this bisector

23. Film stabilization • Film holding instruments • Patient’s finger Film holding instruments • Rinn bisecting angle instrument – include aiming • rings which aid alignment of PID & collimators • Snap - A- Ray • Stable bite block - disposable

24. Finger holding or digital method • Patient’s finger or thumb used to stabilize film • Thumb - maxillary films • Index finger – mandibular films • Patient’s left hand – right side of mouth • Patient’s right hand – left side of mouth

25. Draw backs of finger holding method • Unnecessary radiation exposure of patient’s hand • Excessive pressure – bend film- image distortion • Slipping of film – inadequate exposure

26. vertical Angulations Mandible Projection Incisors Canines Premolars molars Maxilla + 40 degrees + 50degrees + 30 degrees + 20 degrees • 15 degrees • 20 degrees • - 10 degrees • - 5 degrees • Excessive vertical angulation – foreshortening • Insufficient vertical angulation - elongation

27. Horizontal angulation • Central ray is directed Perpendicular to curvature • of arch & through Contact areas of teeth • Angulation is at right angles to facial \ buccal surface • Of teeth

28. ADVANTAGES • Film holder is not necessary when anatomy of patient • Precludes use of film holding device like shallow • palate,Bony growths, sensitive premolar areas • Decreased exposure time

29. Disadvantage • Image distortion : • when short PID used increased • divergence of x-rays – image distortion • Structures farther away from film appear elongated than • those closer to film • Angulation problems: • Without use of film holder & aiming ring difficult to • determine vertical angulation • Unnecessary exposure of patient’s hand

30. Bitewing or interproximal technique Used to examine interproximal surface of teeth • Principle • Film placed in mouth parallel to crowns of both • Upper and lower teeth • Film stabilized when patient bites on bitewing tab • or bitewing film holder • Central ray directed through contact of teeth using • + 10 degree angulation

33. Indications • Detecting interproximal caries in early stages • Reveal secondary caries below restorations • Evaluate periodontal conditions • Provide good perspective of alveolar bone crest • changes in bone height assessed accurately • Detecting calculus deposits in interproximal areas

34. Occlusal Radiography • Displays large segment of dental arch • Useful when patients are unable to open mouth wide • for periapical radiographs

35. Indications • To locate roots & supernumerary , unerupted • & impacted teeth • To localize foreign bodies in jaws & stones • in ducts of sublingual & submandibular glands • To demonstrate & evaluate integrity of anterior, • medial & lateral outlines of maxillary sinus • In examination of patients with trismus • To obtain information about location, nature,extent • & displacement of fractures of maxilla & mandible • To determine medial & lateral extent of disease • in palate & floor of mouth

36. Types • Maxilla • Anterior maxillary occlusal projection • Cross sectional maxillary occlusal projection • Lateral maxillary occlusal projection • Mandibular • Anterior mandibular occlusal projection • Cross sectional mandibular occlusal projection • Lateral mandibular occlusal projection