Dental Equipment - Intraorals

Question 1

What is periapical radiography?

Answer 1

Periapical x-ray showed the whole truth – from the crown to beyond the root where the tooth attaches into the jaw (alveolar ridges) - provides detailed info

Intraoral techniques designed to show individual teeth and the tissues around the apices

– each image usually shows 2 to 4 teeth

Question 2

Describe the anatomy of the typical molar tooth:

Answer 2

The tooth can be divided into the Crown and the root (Apex)

The cross-section of the tooth shows for regions – the enamel, the Dentine, pulp and the cementum

The enamel is a part of the tooth mainly above the gum and consist mainly of calcium phosphate which is very hard

Question 3

Anatomy features seen on the radiograph?

Answer 3

Periodontal ligaments space

Laminar dura

Trabecular pattern

Question 4

How many images are required for a complete survey of an adult?

Answer 4

Normally 14

Question 5

How is a dental abscess formed and what does it lead to?

Answer 5

I dental abscess is caused by infection either entering the pulp cavity – through a crack or the socket – through infection of the gums

This may lead to the formation of puss in the infected area

Question 6

How does a dental abscess present on a radiographic image?

Answer 6

The dental abscess can be seen as an area of radiolucency - normally around the apex of the tooth

This can be obvious or subtle

Question 7

What are the indications for periapical radiography?

Answer 7

Detection of a pickle infection/information

Assessment of Perio dental status

After trauma teeth and associated alveolar bone

Assessment of present/position of an erupted teeth

Assessment of loot morphology player to extraction

Pre-operative assessment and post-operative appraisal of apical surgery

Details evaluation of a pickle cysts and other lesions within the alveolar bone

Evaluation of implants post operatively



Question 8

What is the ideal positioning for intra oral examinations?

Answer 8

The tooth under investigation an image receptor in contact or as close together as possible
- Tooth an image Receptor parallel to avoid distortion
- Image receptor position: long access vertical for incisors and canines
- Long axis horizontal for premolars and molars
- Sufficient area beyond apices to record apical tissues

X-ray tube position such that central Ray perpendicular to an image receptor

Positioning must be reproducible

Question 9

What is a paralleling technique?

Answer 9

Image receptor is placed in a holder and positioned in the mouth parallel to the long axis of the tooth under investigation

The central ray Is positioned to be at right angles to both the tooth and the image Receptor

By using a holder with a fixed image receptor and x-ray tube positions that technique is reproducible



Question 10

What difficulties Can paralleling technique come across?

Answer 10

The anatomy of the palate and shape of the dental arches make positioning of the image receptor difficult – especially in children

Question 11

What is the construction of image receptor holders?

Answer 11

Three basic components:

Holder for image receptor – keeps it parallel to teeth and stops offending

Byte Block

X-ray beam aiming device

Question 12

What determines the holder design used when taking an image?

Answer 12

Depends of the tooth is:
Anterior or posterior

In mandible or maxilla – lower or upper

Right or left side of jaw

(Can be colour-coded to Make identifying holders easier)

Question 13

What are the two types of image receptor holder?

Answer 13

Digital or film packet

Question 14

Go through the process of technique and care when taking an intra oral image?

Answer 14

Three point ID check

Remove any jewellery or artefacts – including dentures and glasses

Patient should be sitting in a chair with their head/next supported, and a close or plain horizontal

Explain the procedure

Welding gloves please see image of sceptre into the holder

Holder/image receptor should be placed personally into the mouth

Cotton wool rolls can be used for patient comfort and ease of positioning

Holder positioned such that teeth under investigation touching bite block

Patient asked to bike gently together on block to stabilise position of holder

Locator ring moved down indicator rod until just touching patients face – correct SID

X-ray tube centred to locator ring – correct horizontal/vertical tube angles: correct SID

Carry out examination quickly to minimise patient discomfort

Question 15

Infection control in intraoral imaging?

Question 16

How is intra oral imaging adapted for children and disabled patients?

Answer 16

Smaller films which can be used for small amounts

It may be necessary to ask for assistance (usually a relative) to hold the image of receptor and provide reassurance

UK guidelines state:

Only radiographic investigations are appropriate to the limitations imposed by the patient’s age, cooperation or disability should be attempted

Question 17

Radiation protection in intra oral technique?

Lead rubber protection

Answer 17

Are necessary to use lead Robert protection in dental radiography

Well done equipment and technique Mean that this is a very low and there is deemed a greater risk of artefact – therefore repeat exposures – caused by the lead rubber protection of used

Question 18

Why is the bisecting angle technique not used very often and what was the solution ?

Answer 18

Virtually obsolete, due to difficulty getting connect film/tube angulation which resulted in distorted images

Solutions was to use holders plus a guide for two regulation – paralleling technique

Question 19

What is the principal/technique of bisecting angle?

Answer 19

Image of receptor placed as close to tooth under investigation as possible

Angle formed between long axis of tooth and long axis of image receptor is assessed and mentally bisected

Central ray directed at right angle to this bisecting line and aimed through tooth Apex

Receptor/film packet positioned Impatience mouth

Patient asked to gently support this in position by placing their finger behind it

Radiographer phone visually assesses the required angulation and positions of tube accordingly


Question 20

Take me killers of bisecting angle technique?

Answer 20

If the central day is angle to steeply – less than 90° – the image of the tooth is a foreshortened

If the central day is angle to shallow – more than 90° – then the image of the tooth is in elongated and there is a danger that the apices are missed

Question 21

What is the bitewing image meant show?

Answer 21

Individual images designed to show the count of the premolar and molar teeth

Ideally they should show no overlap of the surfaces of the teeth

Question 22

What are the indications For a bitewing image?

Answer 22

Detection of caries

monitoring of the progression of caries

Assessment of existing installations – feelings and crowns

Assessment of the Periodontal status

Question 23

 what is the technique for a bite wing images?

Answer 23

Image receptor position centrally within holder; upper and lower edges parallel to bite block

Posterior teeth at image receptor in contact – or as close as possible

Posterior teeth and image receptor must be parallel

In a horizontal plane central ray should be a right angles to teeth and image receptor must be parallel

In vertical plane central Ray should be angled 5 to 8° cauded

Positioning must be reproducible

Question 24

What are the two types of occlusal imaging?

Answer 24

Maxillary occlusals:
Upper standard occlusal – anterior
Upper oblique occlusal

Mandibular occlusals:
Lower 90° occlusal – true occlusal
Lower 45° occlusal – lower or standard occlusal

Question 25

What are the Anterior (upper standard) occlusal indications?

Answer 25

Periapical assessment of upper anterior teeth – especially children also adults unable to tolerate periapical holders

Detect presence and position of uneruprted/supernumerary teeth – especially canines

Evaluation of size and extent of lesions – cyst/tumour

Assessment of fracture of anterior teeth and Alveolar bone

Question 26

What is the technique for the anterior (upper standard) occlusal?

Answer 26

Patience it with head supported and occlusal plane horizontal – parallel to floor

Image receptor place to mouth – portrait for children; landscape for adults – as far is back as possible and patient asked to bite Down gently to keep it in place

X-ray tube positioned above patient in midline and centrally directed through the bridge of nose at angle of 65 to 70° to image receptor

Question 27

What are the lower (lower standard) occlusal indications?

Answer 27

Taken to show the lower anterior teeth and anterior part of mandible

Main clinical indications:
Periapical assessment of Lawrence Heisers especially in patients who cannot tolerate periapical holders

Valuation of size an extent of reasons – cyst/tumour in anterior part of mandible



Question 28

What is the technique for the lower (lower standard) occlusal?

Answer 28

Patience with head supported and occlusal plane horizontal – parallel to the floor

Image receptor place to mouth, portrait, tubeside down, as far back as possible, and patient asked about Down gently to keep it in place

X-ray to position the midline, and central day directed through point of June, at angle of 45° to interceptor

Lower 90° occlusal, true occlusal – often used to detect salivary calculi and projection routinely forms part of preliminary image series prior to submandibular sialogram