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Three projections:
- • Periapicals - Sz2; entire length of crown and root, and >= 2mm bone beyond apex; hard for CCD/CMOS; complete lesion w/ surrounding normal bone; occlusal or panoramic used if lesion too big
- • Bitewings - Sz2; cover crowns, 1/3 of the roots of
- maxillary and mandibular posterior teeth, Surrounding crestal bone, interproximal contacts (and caries); Proximal surfaces of restorations, Depth of caries, Presence of calculus.
- • Occlusals - larger area coverage
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Radiographs optimal technical quality:
- • Minimal distortion.
- • Optimal Density and Contrast.
- • Proper processing.
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Indications for Periapicals
- • Extensive restorations.
- • Extensive caries.
- • Irreversible pulpitis or pulpal necrosis.
- • History of disease.
- • History of RCT or periodontal treatment.
- • Pain/discomfort.
- • Swelling and/or fistula.
- Always inspect the patient before taking radiographs
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Indications for Bitewings
- • Teeth are in contact and occlusion.
- • Clinical suspicion of proximal surfaces.
- • Need to visualize proximal margins of restorations for overhangs, open margins, or recurrent caries.
- • History of smooth surface caries.
- • Proximity of caries or restoration to pulp - Provides estimate on pulp-restoration relation; Clinical diagnosis of reversible pulpitis
- • Periodontal disease ‐ active or in remission; vertical bone loss, angular defect.
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Projection geometry
- Paralleling technique for periapical - receptor parallels long axis
- - long object-film distance -> magnification, fuzziness -> minimized by long collimator; difficult placement in small mouths or around tori
- - parallelism -> minimal geometric distortion
- - long collimator -> less radiation
- Bisecting technique for endo intra-operative - beam perpendicular to imaginary bisector of the angle between long axis of tooth and receptor
- Both require receptor holding instruments
- - Based on Cieszynski’s Rule of Isometry; minimize distortion if done correctly; impossible to see the angle correctly
- - ease of placement of receptors
- - allows use of shorter tubes
- - may slip or bend
- - Difficult to obtain dimensionally accurate images.
- - unequal magnification
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Full mouth series
- B.W. and Periapicals
- "the radiographs necessary to visualize the entire dentition and its supporting structures”.
- The supporting structures: alveolus and maxilla from tuberosity to tuberosity, mandible from retromolar pad to retromolar pad
- Number of images varies due to:
- • Number of teeth.
- • Size of teeth.
- • Size of patient.
- • Existing views.
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Periapicals - Maxillary Central View
- MD wise
- - Both central incisors
- - A portion of the lateral incisors.
- - Contacts clearly visualized
- IC-wise
- - Incisal edges parallel to the edge of the image.
- - At least 2‐3 mm of bone beyond the apex
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Periapicals - Maxillary Canine-Lateral View
- Maxillary canine and lateral incisors and periapical region.
- canine-lateral Contact centered and seen clearly without overlap; other contacts are simply bonuses
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Periapicals - Maxillary Premolar View
- Distal half of canine.
- May extend as far as second molar.
- Occlusal plane parallel to the long edge of the image receptor
- Canine-first molar contacts, no overlapping.
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Periapicals - Maxillary Molar View
- Distal half of 2nd PM
- Three molars
- Tuberosity
- An additional image may be required to visualize the maxillary tuberosity.
- Occlusal plane parallel to the long edge of image
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Periapicals - Mandibular Central View
- all four incisors
- mesial of canines
- Apices plus several mm of bone; Crestal bone
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Periapicals - Mandibular Canine Lateral View
- mandibular canine
- lateral incisors
- periapical region
- canine-lateral contact centered and shown without overlap
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Periapicals - Mandibular Premolar View
- Distal half of canine
- PMs
- up to 2M
- Occlusal plane parallel to the image long edge
- Contacts shown clearly from canine to 1M
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Periapicals - Mandibular Molar View
- Distal half of 2PM
- Molars
- Contacts seen clearly.
- Supplemental views may be necessary to show 3M completely
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BW - Premolar
- Distal of maxillary and mandibular canines
- Crowns and crestal bone from distal of canines to first molars
- Contacts seen clearly.
- Occlusal plane parallel to the image long edge
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BW - Molar
- Distal of 2PM
- Up to the distal of the last molars.
- Contacts seen clearly.
- Occlusal plane parallel to the image edge.
- Crowns and crestal bone seen clearly
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Vertical Bitewings
- Indicated by periodontal bone loss.
- Fields of view are similar to horizontal bitewings.
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XCP instruments
- Film Positioning Instruments
- Rinn XCP instruments are used at RSDM.
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XCP Instruments ‐ New
- Full Mouth Series contains:
- • 1 anterior ring.
- • 1 posterior ring.
- • 3 connecting rods.
- • 3 bite blocks.
- • All in a sealed sterilized package/cassette
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XCP Instruments ‐ Old
- • Interchangeable with new parts.
- • Easier to ”lock‐in” rectangular collimator.
- • Will be phased out as existing stock is retired.
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XCP ORA
- anterior (blue), posterior (yellow), bitewing (red)
- Cotton rolls, secured by rubber band, help to stabilize the instruments in the patient’s mouth.
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Occlusal Views
- • Displays large segment of maxilla or mandible.
- • Cross‐sectional or topographical.
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Indications for Occlusal Radiographs
- • Trauma.
- • Patient unable to open fully.
- • Large lesions.
- • Localize lesions and impacted teeth.
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Maxillary Occlusal View
- • Displays relatively large area.
- • Excellent for displaying alveolar fractures, periapical lucencies, and midline anomalies such as cleft palates.
- 60 degrees
- foreshortening, distortion, overlapping, all OK
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Mandibular Topographical Occlusal View
- • Displays symphyseal fractures and other midline anomalies.
- • Excellent for patients with limited opening.
- 55 degrees
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Mandibular Cross‐sectional Occlusal Views
- • Displays 90 Degree view from periapicals and panoramic.
- • Shows expansile lesions, pans can't
- • Can isolate stones in the submandibular duct, pans can't
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Primary beam - attenuation -> remnant beam - receptor -> image
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The main problems of perception of radiograph can be caused by the effects of:
- Partial images - different density shadows
- Contrast - contrast of surrounding
- Context - patient's description
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Radiopaque dense structures
- cortical bones - Borders, Floors, Ridges, Tuberosity, Processes, Tubercles, Septa, Spine
- metal
- enamel
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Area of Radiolucency
- Fossae
- Sinus
- Dental pulp
- Marrow spaces
- Foramina
- Recesses
- Sutures
- Canals
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Cervical burnout
- artifact that mimics caries, loss of structure
- Appears between enamel cap and the crest – due to contrast of adjacent radiopaque enamel
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