Bitewing radiographyBitewing radiography

Main indicationsMain indications

Detection of interproximal cariesDetection of interproximal caries

Monitoring the progression of dental cariesMonitoring the progression of dental caries

Assessment of existing restorationsAssessment of existing restorations

Assessment of the periodontal statusAssessment of the periodontal status

Ideal technical requirementsIdeal technical requirements

The bite-platform should be positioned on The bite-platform should be positioned on the middle of the film packet and parallel the middle of the film packet and parallel to the upper and lower edges of the film to the upper and lower edges of the film packetpacket

The film packet should be positioned with The film packet should be positioned with its long axis horizontally for a its long axis horizontally for a horizontal horizontal bitewing bitewing or vertically for a or vertically for a vertical bitewing\vertical bitewing\

The posterior teeth and the film packet should be The posterior teeth and the film packet should be in contact or as close as possiblein contact or as close as possible

The posterior teeth and the film packet should be The posterior teeth and the film packet should be parallel- the shape of the dental arch may parallel- the shape of the dental arch may necessitate two separate film positions to achieve necessitate two separate film positions to achieve this requirement for the premolars and the molarsthis requirement for the premolars and the molars

In the horizontal plane, the X-ray tubehead should In the horizontal plane, the X-ray tubehead should be aimed so that the beam meets the teeth and the be aimed so that the beam meets the teeth and the film packet at right angles, and passes directly film packet at right angles, and passes directly through all the contact areasthrough all the contact areas

II

In the vertical plane, the X-ray tubeheadIn the vertical plane, the X-ray tubehead

should be aimed downwards approximatelyshould be aimed downwards approximately

5 to 8 degrees to the horizontal to 5 to 8 degrees to the horizontal to compensate for the upwardly rising curve of compensate for the upwardly rising curve of SpeeSpee

The positioning should be reproducible The positioning should be reproducible

Positioning techniquesPositioning techniques

Using a tab attached to the film packet and Using a tab attached to the film packet and aligning the X-ray tubehead by eyealigning the X-ray tubehead by eye

Using a holder with beam-aiming device to Using a holder with beam-aiming device to facilitate the positioning and alignment of facilitate the positioning and alignment of the X-ray tubeheadthe X-ray tubehead

Film holdersFilm holders

Basic components of film holdersBasic components of film holders

A mechanism for holding the film packet A mechanism for holding the film packet parallel to the teethparallel to the teeth

A bite platform that replaces the wingA bite platform that replaces the wing

An X-ray beam-aiming device An X-ray beam-aiming device

The appropriate size film is selected as The appropriate size film is selected as follows:follows:

- Large film packets ( 31*41mm ) for adultsLarge film packets ( 31*41mm ) for adults

- Small film packets ( 22*35 mm ) for Small film packets ( 22*35 mm ) for children under 12 years. Once the second children under 12 years. Once the second permanent molars have erupted the adult permanent molars have erupted the adult size film is required size film is required

The patient is positioned with the head supported and The patient is positioned with the head supported and occlusal plane horizontalocclusal plane horizontal

The operator holds the tab between thumb and The operator holds the tab between thumb and forefinger and inserts the film packet into the lingual forefinger and inserts the film packet into the lingual sulcus opposite the posterior teethsulcus opposite the posterior teeth

The anterior edge of the film packet should be positioned The anterior edge of the film packet should be positioned opposite the distal aspect of the lower canine- in this opposite the distal aspect of the lower canine- in this position, the posterior edge of the film packet extends position, the posterior edge of the film packet extends usually just beyond the mesial aspect of the lower third usually just beyond the mesial aspect of the lower third molarmolar

The tab is placed on to the occlusal surfaces of The tab is placed on to the occlusal surfaces of the lower teeththe lower teeth

The patient is asked to close the teeth firmly The patient is asked to close the teeth firmly together on to the tabtogether on to the tab

As the patient closes the teeth, the operator As the patient closes the teeth, the operator pulls the tab firmly between the teeth to ensure pulls the tab firmly between the teeth to ensure that the film packet and the teeth are in contactthat the film packet and the teeth are in contact

The operator releases the tabThe operator releases the tab

The X-ray beam is aimed directly through the The X-ray beam is aimed directly through the contact areas, at right angles to the teeth and contact areas, at right angles to the teeth and the film packet, with an approximate 5-8 degrees the film packet, with an approximate 5-8 degrees downward vertical angulationdownward vertical angulation

To ensure that the anterior part of the film is To ensure that the anterior part of the film is exposed the front edge of the cone should be exposed the front edge of the cone should be positioned adjacent to the corner of the mouthpositioned adjacent to the corner of the mouth

Advantages of using film packets Advantages of using film packets with tabswith tabs

SimpleSimple

InexpensiveInexpensive

The tabs are disposable, so no extra cross- The tabs are disposable, so no extra cross- infection control procedures requiredinfection control procedures required

Can be used easily in childrenCan be used easily in children

DisadvantagesDisadvantages

Operator-dependent assessment of horizontal Operator-dependent assessment of horizontal and vertical angulation of the X-ray tubeheadand vertical angulation of the X-ray tubehead

Radiographs are not reproducibleRadiographs are not reproducible

Cone cutting is commonCone cutting is common

The tongue can easily displace the film packetThe tongue can easily displace the film packet

Advantages of film packet holdersAdvantages of film packet holders

SimpleSimple

Film packet held firmly in position and cannot be Film packet held firmly in position and cannot be displaced by the tonguedisplaced by the tongue

X-ray beam is always at right angles to the film X-ray beam is always at right angles to the film packetpacket

Avoid cone cuttingAvoid cone cuttingHolders are autoclavableHolders are autoclavable

DisadvantagesDisadvantages

Positioning of the film holder can be Positioning of the film holder can be uncomfortable for the patientuncomfortable for the patient

Some holders are relatively expensive Some holders are relatively expensive

Holders are not suitable for childrenHolders are not suitable for children

Ideal exposure factorsIdeal exposure factors

Assessment of caries and restoration-high kV Assessment of caries and restoration-high kV which ensures good contrast to allow which ensures good contrast to allow differentiation between enamel, dentin and allow differentiation between enamel, dentin and allow EDJ to be seenEDJ to be seen

Assessment of periodontal status- low kV to Assessment of periodontal status- low kV to avoid burn-out of the thin alveolar crestal boneavoid burn-out of the thin alveolar crestal bone

In the X-ray machines with fixed kV and mA In the X-ray machines with fixed kV and mA these results are achieved through exposure these results are achieved through exposure time time