DN14 Flashcards
WHAT DO DENTAL RADIOGRAPHS DETECT AND DIAGNOSE?
lesions and structures such as:
- DENTAL CARIES - this shows up as a dark area of destruction extending inwards from the enamel surface
- PRESENCE AND EXTENT OF PERIODONTAL DISEASE - this shows up as a loss of the laina dura forming the crest of the alveolar bone, loss of height of the alveolar bone, and a widening of the periodontal ligament
- PERIODONTAL AND PERIAPICAL ABSCESSES - chronic alveolar abscesses show up as a dark circular area at the apex of an affected tooth, caused by destruction of the apical lamina dura and spongy bone
- CYSTS AFFECTING THE DENTAL TISSUES - tehse can show up as enlarged darker areas surrounding other structures, and can sometimes be seen to be pushing tooth roots out of their normal positions
- LATROGENIC PROBLEMS - i.e. those caused by the dentist, such as overhanging restorations or tooth perforations by posts
- to detect SUPERNUMERARY teeth and UNERUPTED teeth or to determine the CONGENITAL ABSENCE of unerupted teeth
- to diagnose HARD TISSUE LESIONS, such as bone cysts and tumours, salivary calculi and jaw fractures
WHAT TREATMENTS MAY REQUIRE RADIOGRAPHS TO AVOID PROBLEMS OCCURING AND TO ENSURE TREATMENT IS SUCCESSFUL?
- to aid in ENDODONTIC treatment
- to determine the number and position of tooth roots before EXTRACTION
- to ensure the health of a tooth before it undergoes CROWN OR BRIDGE preparation
- to ensure the health of a tooth before it is used as an abutment during DENTURE CONSTRUCTION
WHAT ARE THE LEGISLATIONS AND GUIDELINES PUT IN PLACE WHEN USING X-RAYS IN DENTISTRY?
- all use of dental imaging has to be CLINICALLY JUSTIFIED - so there must be a clinical reason why the patient is being exposed to the x-rays
- the dose of x-rays used must be kept AS LOW AS REASONABLY ACHIEVABLE (ALARA) - so that the minimum dose of x-rays must be used, for the shortest time, and aimed at the smallest area of tissue possible to produce a functional image, this is now more usually reffere to being AS LOW AS REASONABLY PRACTICABLE/POSSIBLE (ALARP)
- only the patient should be exposed to the x-ray beam - all staff and family members must be outside the CONTROLLED ZONE during the exposure
- machines must be well maintained and serviced regularly
- no untrained personnel can be invloved in radiation exposure procedures
- QUALITY ASSURANCE (QA) SYSTEMS must be operated to ensure that the dental images produced are to a consistently high standard
WHAT LEGISLATIONS ARE PUT IN PLACE TO ENSURE HEALTH AND SAFETY OF IONISING RADIATION?
- IONISING RADIATION REGULATIONS 1999 - IRR99 - this is concerned with the protection of staff
- IONISING RADIATION (MEDICAL EXPOSURE) REGULATIONS 2000 - IR(ME)R 2000 - this is concerned with the protection of patients
- the aim of both sets of regulations is to keep the number of X-ray exposures and their dose levels, to the absolute minimum required for clinical necessity at all times.
WHAT ARE THREE FACTORS THAT HELP REDUCE THE AMOUNT OF SCATTERED RADIATION CREATED DURING A DENTAL EXPOSURE BY 40%?
USE OF FAST FILMS - f speed intra-oral films are currently availible and require the shortest possible exposure time to create the radiographic image, once processed.
SHORT EXPOSURE TIME - achievable with a combination of modern x-ray machines, fast films and intensifying screens in extra-oral cassettes
RECTANGULAR COLLIMATOR TUBES - these have replaced the old plastic aiming cones of intra-oral machines, and produce a parallel x-ray beam rather than a disorganised ‘spray’ effect with lots of scattered rays
COMPLIANCE WITH IRR99 REGULATION
the initial act of compliance is to inform the health and safety executive of its use on the premises. three formal appointments must then be made by the workplace owner:
LEGAL PERSON - a designated person who is to ensure the workplace’s full compliance with both sets of regulation (this is usually the employer)
RADIATION PROTECTION ADVISER (RPA) - a medical physicist who is appointed in writing by the dental workplace and is availibile to give advice on staff and public safety in relation to both sets of regulations
RADIATION PROTECTION SUPERVISOR (RPS) - a designated person in the workplace who can assess risks and ensure precautions are taken to minimise them, in accordance with IRR99
THE ROLE OF THE RADIATION PROTECTION ADVISER (RPA) WITH IRR99
- the correct installation of all new x-ray machines
- the regular maintenance and certificated checks that are required for each X-ray machine to ensure that the minimum exposure to radiation occurs
- the CONTINGENCY PLANS that need to be in place in case of an x-ray machine malfunctioning
- the investigation of any malfunction of an x-ray machine
- the designation of a 1.5 metre controlled area around each x-ray machine and within the primary beam direction, where no one but the patient may be present during an exposure
- advice on RISK ASSESSMENTS with regard to restricting staff and patient exposure to ionising radiation, and review the assessments every five years
- advice on the necessary staff training required so that designated duties are carried out competently and safetly
THE ROLE OF THE RADIATION PROTECTION SUPERVISOR (RPS) WITH IRR99
the role of the RPS is to carry out the following:
- ensure all staff members have suitable training according to the level of their legal responsibility
- carry out risk assessments with regard to restricting radiation exposure
- ensure the local rules remain current, updating as necessary
- maintain teh contents of the necessary ‘radiation protection file’
- organise and run QA programmes in relation to the safe use of ionising radiation
- organise and run quality control tests or delegate the tests to suitably trained members of staff
ROLES AND RESPONSIBILITIES WITH IR(ME)R 2000
REFERRER - the dentist who refers the patient for radiation exposure, either to themselves or another dentist or specialist dental radiographer who can carry out the exposure
IRMER PRACTITIONER - the dentist or specialist dental radiographer who takes responsibility for JUSTIFYING the taking of the radiograph, by determining that the diagnostic benefits gained will outweigh the risks of the exposure to the patient
OPERATOR - any member of the dental team who carries out all or part of the practical duties involved with the exposure and processing of the radiograph, including:
- patient identification
- positioning of the film, the patient and the machine tube head
- setting the exposure controls
- pressing the exposure button
- processing the film
- evaluating the quality of the radiograph
- carrying out test exposures for QA purposes
- running QA programmes
KEY POINTS OF PATIENT PROTECTION WITH IR(ME)R REGULATION
- PATIENT IDENTIFICATION - to avoid the wrong patient being exposed, name, address and date of birth should be used as a minimum
- REFERRER AND IRMER PRACTITIONER - can only be dentists, as only they have the training to determine when an exposure is required for diagnosis and treatment
- JUSTIFICATION - the benefit of exposing the patient should outweigh the risk of causing tissue damage
- OPTIMISATION - the dose of radiation should be in line with ALARA/P principles at all time
- PREGNANT PATIENTS - routine dental exposure techniques do not irridate the pelvic area and involve such low doses that pregnancy is not considered a contraindiction to undergoing irridation
- STAFF TRAINING - written evidence of all necessary training pertinent to ionising radiation techniques must be kept for all personnel in the radiation protection file, as documented proof of their competence in the duties that they undertake
- QUALITY ASSURANCE - QA programmes and audits provide a valuable tool for determining wherher the systems in place protect patients (and staff) from any potential harm from ionising radiation are actually working, by looking at the procedures in place and the results achieved
- ACCIDENTAL EXPOSURE - all x-ray machines must have an isolation switch outside the controlled are, an illuminated control panel or switch to indicate when the mains power is on, and an additional light and an audible buzzer that are activated during exposure time itself.
WHAT IS THE RADIATION PROTECTION FILE AND WHAT DOES IT CONTAIN?
this acts as a summary document that holds as much information as possible about the procedures in place to ensure radiation protection within the a=particular workplace. it should be reviewed and kept updated anually to ensure that it remains relevent and effective. it should contain all the following information:
- formal appointments of staff on the premises
- reference to the initial risk assessment carried out by the legal person, in consultation with the RPA
- local rules for each x-ray set out on the premises
- procedures for ensuring patient protection
- information on how ALARA/P is achieved
WHAT DO INTRA-ORAL FILMS CONTAIN?
- plastic envelope to protect the contents from saliva contamination
- wrap-around black paper to prevent exposure of the film to light
- film - which is exposed to the ionising radiation and producers the dental image once processed or loaded onto the computer
- lead foil to prevent scatter of the ionising radiation past the film packet
- raised pimple marker on the film and packet side towards the x-ray tube, which is used to correctly determine the left and right sides of the image produced
WHAT DO EXTRA-ORAL FILMS CONTAIN?
- cassette case that is loaded into special imaging machines for use
- intensifying screens in both sides of the cassette, to reduce the dose of radiation exposure required ro produce a dental image
- film, of a compatible type with the intensifying screens, to produce the dental image once exposed and processed
- marker to correctly determine the left and right sides of the image produced
WHAT ARE THE INTRA-ORAL VIEWS?
- HORIZONTAL BITEWING
- VERTICAL BITEWING
- PERIAPICAL
- ANTERIOR OCCLUSAL
WHAT ARE THE EXTRA-ORAL VIEWS?
- DENTAL PANORAMIC TOMOGRAPH (DPT) - shows both jaws and their surrounding bony anatomy, and is taken for orthodontic and wisdom tooth assessments, as well as to help diagnose pathology and jaw structures
- LATERAL OBLIQUE - shows the posterior portion of one side of the mandible, including the ramus and angle and the lower molar teeth, and is an alternative to a DPT to view the position of unerupted third molar teeth
- LATERAL SKULL RADIOGRAPH - this is a view of the side of the head, and is taken in a specialised machine called a CEPHALOSTAT and is used to monitor jaw growth and determine orthognathic surgery techniques in complicated cases of maloclussion