RADIOGRAPHIC TECHNIQUES DR SAMY I AL-AGHA A.PROFESSOR OF RADIOLOGY AL-AZHAR –GAZA UNIVERCITY
RADIOGRAPHIC TECHNIQUES CLASSIFICATION A-Periapical B-Bite-wing C-Occlusal
PERIAPICAL RADIOGRAPHIC TECHNIQUES 1-BISECTING ANGLE TECNIQUE A-Patient,s position • For maxillary teeth>>>ala tragus line is parallel to floor • For mandibular teeth>>>line from tragus to corner of mouth is parallel to floor
PERIAPICAL RADIOGRAPHIC TECHNIQUES B-Film placement: • Tube side of the film packetis towards the tube. • The film(short dimension) is parallel to occlusal plane(For anterior region) • The film (long dimension) is parallel to occlusal plane(For posterior region) • Avoid over-bending of film packet • The area of interest is in the center of film.
PERIAPICAL RADIOGRAPHIC TECHNIQUES • 2-3mm of film packet should be left beyond the occlusal plane • The patient holds the packet with finger • Avoid movements of patient,film,or cone during exposure. C-Cone,s position: 1-Central ray(C.R)angulation a-V.A b-H.A 2-Point of entry
PERIAPICAL RADIOGRAPHIC TECHNIQUES Vertical angulation • Denotes the angle between C.R&occlusal plane • Vertical angle of maxillary teeth(+ve) Incisors>>>>>>55-60 Canines>>>>>>45-50 Premolars>>>>35-40 Molars>>>>>>25-30
PERIAPICAL RADIOGRAPHIC TECHNIQUES V.A for mandibular teeth(-ve) Incisors>>>>>>15-20 Canines>>>>>>10-15 Premolars>>>>5-10 Molars>>>>>>0-5 Increase V.A 5 in a-shallow palate or floor of mouth b-flat ridges(edentulous pt) c-inclined teeth
PERIAPICAL RADIOGRAPHIC TECHNIQUES • Decrease V.A 5 in case a-high palate b-deep floor of mouth Horizontal angulation • It is the angle between CR&mid-sagittal plane • It control width(dimention of tooth) • CR must project through interproximal surfaces of examined teeth
PERIAPICAL RADIOGRAPHIC TECHNIQUES • H.A Incisor>>>>>zero Canines>>>>45-60 Premolars>>>60-70 Molars>>>>>>90 Point of entry • The cone is positioned so that CR is directed to apices of the teeth
PERIAPICAL RADIOGRAPHIC TECHNIQUES • For maxillary teeth>>>points of entry are located on ALA TRAGUS LINE Incisors>>>>>tip of the nose Canines>>>>>0.2cm distal to ala of nose Premolars>>>vertical line from eye pupil to ala tragus line 1st Molar>>>>vertical line from outer canthus to ala tragus line
PERIAPICAL RADIOGRAPHIC TECHNIQUES 2nd Molar>>>vertical line from 1cm distal of outer canthus to ala tragus line 3rd Molar>>>>vertical line from 2cm distal of outer canthus to ala tragus line • For mandibular teeth >>>the same as for maxillary teeth but located on a line 0.5cmabove inferior border of the mandible • Time of exposure depends on area of rediographed,KV,mA, film speed&age of Pt
PERIAPICAL RADIOGRAPHIC TECHNIQUES Advantages of bisecting angle technique 1-Easy,quick &comfortable 2-Used in all patients 3-short object-source distance>decrese exp time 4-periapical area can be demonstrated 5-Speed technique Disadvantages: 1-Not standerdized 2-error of angulation>>>superimpositionof structures over the area of interest
PERIAPICAL RADIOGRAPHIC TECHNIQUES 2-The paralleling technique(long cone tech) or Right angle technique • C.R is perpendicular to both film &tooth • The film is placed in mid of oral cavity to get parallism between tooth&film>>>image magnification&unsharpness. • Target-object distance is increased to avoid unsharpness(16 inches)>>>increase KV,mA,s and fast film(increase exposure time 4times) • Film holders are used.
PERIAPICAL RADIOGRAPHIC TECHNIQUES FILM HOLDERS: 1-Rinn instrument 2-Bite block 3-hemostat 4-Cotton rolls 5-Precision rectangular collimating instrument Advantages of film holders 1-Provide parallism 2-Avoid exposure to Pt fing Disadvantages 1-Closure of mouth before exposure 2-Cannot examin the periapical structures 3-Limited in small mouths or gagging sesation
PERIAPICAL RADIOGRAPHIC TECHNIQUES ADVANTAGES OF PARALLELING TECHNIQUE 1-Standerdized>>>used in research 2-Accurate images 3-Avoids superimposition on apices 4-H.A&V.A detrmined by positioning devices 5-No overbending of films
PERIAPICAL RADIOGRAPHIC TECHNIQUES DISADVANTAGES OF PARALLELING TECHNIQUE 1-Difficult to image all parts of the mouth 2-Increased exposure time 3-Need long cones &film holders 4-Cannot image apical area in shallow palate 5-Discomfort of film holder 6-Time consuming
BITE-WING TECHNIQUE • Used mainly for posterior teeth. • The wing is on the tube side of film backet. • Film backet is parallel to long axis of coronal portion of upper &lower teeth. • CR is perpendicular to center of film
BITE-WING TECHNIQUE TECHNIQUE • MSP is perpendicular to floor&ala tragus line is parallel to floor • Remove any metallic objects. • Patient should close mouth during exposure. • For premolar teeth >>>the film bite should be centered over the lower 2nd premolar &anterior border of the film extends anteriorly beyond the lower canine and 1st premolar.
BITE-WING TECHNIQUE • For molar teeth>>>the posterior border of film is behind the distal surface of most posteriorly erupted molar &the film bite is centered over the lower molar teeth. • The patient should close his mouth in centric occlusion when radiography of posterior teeth • In edentulous patient replace missing teeth by cotton rolls
BITE-WING TECHNIQUE In anterior bitewing film we shoul use 1-smaller film size 2-short dimension is parallel to occlusal plane 3-patient closes his mouth in edge to edge position 4-longer wing to avoid bending of film
BITE-WING TECHNIQUE CONE POSITION • CR IS PERPENDICULAR to film packet. • +ve 5 for premolar &10 for molar(short cone) • +ve 6 for premolar &8 for molar (long cone) • For posterior teeth use 2 films • For anterior teeth use 3 films
PANORAMIC RADIOGRAPHY • Produces radiographs for only one section (slice) of the patient. • Patient is placed so that dental arches are located in the middle of focal plane. • Patient places edges of incissors in bite block device. • MSP in midline position. • Patient,s occlusal plane is lowered 20-30 degrees below horizontal plane.
PANORAMIC RADIOGRAPHY • Patient,s back is in erect position with extended neck. • Patient should hold tongue in contact with hard palate &keep lips closed during exposure • Patient,s breathing is shallow during exposure
PANORAMIC RADIOGRAPHY INDICATIONS 1-Evaluation of truama &3rd molars. 2-Evaluation of teeth development. 3-Evalution of developmental anomaly. 4-Examination of maxillary sinuses.
PANORAMIC RADIOGRAPHY ADVANTAGES: • Imaging broad anatomic region. • Relative low radiation dose. • Convenient,easy &speedy. DISADVANTAGES: • Fine anatomic details are not demonstrated. • Magnification,geometricdistortion&overlapping of teeth. • High cost.
EXTRA-ORAL TECHNIQUES 1-Lateral views: a-True lateral b-Lateral oblique 2-PA views: a-True PA b-Sinus(Water,s view) c-Reversed Town,s view 3-AP views: a-True AP b-Modified Town,s c-SMV d-Frontal TMJ(transorbital)