intra-oral tech-errors学会看拍牙课件.ppt

intra-oral tech-errors学会看拍牙,1,Intraoral Technique Errors The following slides identify the most common errors seen when taking intraoral radiographs.,intra-oral tech-errors学会看拍牙,2,Film Placement Errors,Anterior-posterior placement Vertical placement (too far above or below occlusal plane) Film tipping,intra-oral tech-errors学会看拍牙,3,Poor film placement. (too ant. for PM, too post. for molar),intra-oral tech-errors学会看拍牙,4,AP,Incorrect film placement,intra-oral tech-errors学会看拍牙,5,Premolar bitewing, too posterior,intra-oral tech-errors学会看拍牙,6,Molar bitewing, too anterior,intra-oral tech-errors学会看拍牙,7,Film tipped,intra-oral tech-errors学会看拍牙,8,Film tipped,intra-oral tech-errors学会看拍牙,9,Film tipped (as patient closed, top edge of film caught palatal gingiva, forcing film down),intra-oral tech-errors学会看拍牙,10, 1/4” of film beyond occlusal,intra-oral tech-errors学会看拍牙,11,Patient not biting on biteblock (see next slide). Apices of incisors cut off.,intra-oral tech-errors学会看拍牙,12,Patient not biting on biteblock,intra-oral tech-errors学会看拍牙,13,Cone Cutting,X-ray beam not centered on film, leaving part of film unexposed.,Unexposed part of film (below dotted line),intra-oral tech-errors学会看拍牙,14,Cone Cutting,(paralleling technique),Improper instrument assembly (ring upside down),(side view),intra-oral tech-errors学会看拍牙,15,Cone cutting,intra-oral tech-errors学会看拍牙,16,Cone cutting (bisecting angle technique),intra-oral tech-errors学会看拍牙,17,(bitewing technique),Cone Cutting,intra-oral tech-errors学会看拍牙,18,Cone cutting,intra-oral tech-errors学会看拍牙,19,Overlap (Incorrect horizontal angulation),intra-oral tech-errors学会看拍牙,20,Correct Horizontal Angulation,X-ray beam directed perpendicular to a line connecting the buccal surfaces of the teeth (dotted line below). When using the paralleling instrument, the film should be parallel to this line.,intra-oral tech-errors学会看拍牙,21,Incorrect Horizontal Angulation,If the x-ray beam is not perpendicular to the line connecting the buccal surfaces of the teeth, overlap between the buccal surface of one tooth and the lingual surface of the adjacent tooth occurs (see next slide).,intra-oral tech-errors学会看拍牙,22,Overlap (incorrect horizontal),lingual,buccal,intra-oral tech-errors学会看拍牙,23,Overlap of crowns (black arrows) and roots (red arrow),intra-oral tech-errors学会看拍牙,24,All contacts overlapped,intra-oral tech-errors学会看拍牙,25,Generalized overlap,intra-oral tech-errors学会看拍牙,26,Not a technique error. Overlapped contact (arrow above) is caused by one of the molars being out of normal alignment; all other contact areas are open.,intra-oral tech-errors学会看拍牙,27,Reversed Film,The all-white side of the film should face the teeth. When placing the film in the biteblock of the paralleling instrument (periapical or bitewing), the all-white side of the film should face the ring. When using stick-on tabs for bitewings, the tabs should be placed on the all-white side of the film.,intra-oral tech-errors学会看拍牙,28,Reversed film. The lead foil, which is embossed with a pattern and is normally behind the film when positioned properly, is now in front of the film, producing the tire-track pattern seen on the left side of the film. The film is also lighter than it should be.,intra-oral tech-errors学会看拍牙,29,Vertical Angulation Errors,Results in an image of the tooth that is longer or shorter than the actual tooth. Primarily seen when using the bisecting angle technique.,intra-oral tech-errors学会看拍牙,30,Elongation,intra-oral tech-errors学会看拍牙,31,Elongation Not enough vertical angulation. (The black arrow points to the end of tooth image; the white lines represent the actual length of the tooth).,intra-oral tech-errors学会看拍牙,32,Foreshortening,intra-oral tech-errors学会看拍牙,33,Foreshortening Too much vertical angulation. (The arrow points to the end of the tooth; the white lines represent the actual length of the tooth).,intra-oral tech-errors学会看拍牙,34,Double Exposure Caused by inadvertently using the same film to expose two different areas of the mouth,intra-oral tech-errors学会看拍牙,35,Double exposure,intra-oral tech-errors学会看拍牙,36,Double exposure,intra-oral tech-errors学会看拍牙,37,Patient Movement Results in a blurring or apparent double image of the teeth and surrounding structures. Slight movement of the tubehead, in the absence of patient movement, will not affect the images on the film.,intra-oral tech-errors学会看拍牙,38,Patient movement. Images of all structures on film are blurred.,intra-oral tech-errors学会看拍牙,39,Patient or film movement. Patient may have opened mouth slightly during the exposure, allowing the film to move and creating the double image. (May be confused with double exposure).,intra-oral tech-errors学会看拍牙,40,Patient movement (see explanation on previous slide).,intra-oral tech-errors学会看拍牙,41,Failure to remove appliances, glasses,intra-oral tech-errors学会看拍牙,42,Failure to remove glasses,intra-oral tech-errors学会看拍牙,43,Failure to remove partial denture,intra-oral tech-errors学会看拍牙,44,Miscellaneous errors,intra-oral tech-errors学会看拍牙,45,Exposure levels,overexposure (too dark),underexposure (too light),just right,intra-oral tech-errors学会看拍牙,46,Film bending Most frequently caused by placing the finger in an unsupported area while using the bisecting angle technique. Most obvious in canine region on this film, where root curves off of film. Note hypercementosis on root of second premolar (first premolar is missing).,intra-oral tech-errors学会看拍牙,47,Excessive film softening (black lines),intra-oral tech-errors学会看拍牙,48,PID,Beam directed through top of thyroid collar.,intra-oral tech-errors学会看拍牙,49,Beam blocked by collar; bottom of film unexposed.,intra-oral tech-errors学会看拍牙,50,Finger in path of x-ray beam (arrow), between PID and film.,intra-oral tech-errors学会看拍牙,51,Unnecessary Films,intra-oral tech-errors学会看拍牙,52,(film 1 of 2) Premolar bitewing shows all teeth on right side,intra-oral tech-errors学会看拍牙,53,film 2 of 2 Molar bitewing not needed (edentulous area will be seen on periapical or pan),intra-oral tech-errors学会看拍牙,54,Bitewing of denture teeth. This film is unnecessary, unless you plan to restore these teeth.,