OH30 2012 Design and manufacture removable orthodontic appliances

Overview

This standard describes the manufacture of removable orthodontic appliances. To design and manufacture removable orthodontic appliances, you need to understand, and be able to apply, the theoretical principles of the required orthodontic treatment and the role of the appliance within that treatment plan. The standard covers the processes of manufacturing components, assembling components, blocking out, surveying and undercut relief; application of appropriate baseplate material, processing of polymeric and the final finishing processes. The term â€˜client' has been used to mean the clinician who has prescribed and specified the orthodontic appliance. Clients may be external to the organisation (such as other laboratories, dental practitioners, training schools) or internal (within a dental hospital). The patient is the individual for whom the appliance is being made. Users of this standard will need to ensure that practice reflects up to date information and policies. Version No 2

Knowledge and Understanding

You will need to know and understand:

skeletal anatomy, physiology and tooth morphology necessary for removable orthodontic appliance manufacture
the function and movement of the oral musculature and temporomandibular joint
principles of occlusion and its effect on function of removable orthodontic appliances
disorders and diseases affecting the oral cavity
the aetiology and classifications of malocclusions
growth and eruption patterns of both deciduous and permanent teeth
the physiological changes related to tooth movement
the broader factors (sociological, behavioural, environmental and economic) that contribute to oral health and illness
the aims and objectives of orthodontic treatment
key factors in the success of orthodontic treatment specifically anchorage, fixation, retention, common problems and the common causes of failure of treatment
the stages in, and types of, orthodontic treatment and how they relate to each other
the principles of removable orthodontic appliance design and manufacture
the scope of orthodontic treatment using removable orthodontic appliances
the different types of removable orthodontic appliances and the components that are required
the different components used in removable orthodontic appliances, the purposes and uses of each
the use of casts in the design, manufacture and positioning of components for appliances
the principles of current best practice in relation to model trimming, how to apply them and evaluate the outcomes
principles of baseplate and biteplane design and manufacture
the nature and purpose of study casts
application and magnitude of the forces used in the movement of teeth
methods of activation and reactivation of components
methods of activation and reactivation of removable appliances
how appliances are fitted, adjusted and activated
methods of modification and maintenance of removable appliances
the records (paper and material) that are required
how the curing process affects the choice of materials and manufacturing processes
how to identify the size and type of components that will be required
the range of pre-formed components that are available and methods to assess their suitability for use in constructing an appliance
the different gauges of wire that are used for different types of components and methods for identifying which is required and suitable
methods of straightening and bending wire and the tools that are used
handling tolerances of wires, the effects of over-handling and how to identify when this has happened
methods of assessing the suitability of manufactured components
the purpose and use of the different types of biteplanes and how these are constructed
methods for the application of polymeric material, why different techniques are used
uses of spot welding and soldering
how the duration and level of current affects the strength and viability of the join produced
how to judge when metals have been heated sufficiently to melt solder, but not interfere with the metal's mechanical structure
the consequences of over-heating metals and solder during soldering including weakening and softening metals and causing solder to spatter rather than flow smoothly, the effect of these on the strength and integrity of the join and the remedial action that can be taken
how to identify reasons for soldered joint failure
the different curing methods, how each works, their effect and the situations in which each is best used
how the curing process affects the materials and components that can be used
physical characteristics of materials used in appliances and how the curing processes affect them
the different separating media, when and why these are used
methods of deflasking
the ways in which appliances are cleaned in preparation for finishing and polishing
techniques for finishing and polishing appliances
the different types of abrasive and polish, the purposes and uses of each
methods for the safe and effective cleaning of appliances
methods of assessing and checking the safety, aesthetic, functional and clinical acceptability of completed appliances
the selection of a suitable articulator for the type of appliance being designed and manufactured
centric occlusion records
the importance of aesthetics in the manufacture of orthodontic appliances and the necessity to include artificial teeth if required
lateral and protrusive movement records and their uses
methods of developing, maintaining and improving communication and information relating to the provision of custom-made dental devices
the importance of communicating with individuals at a pace, in a manner, and at a level appropriate to their understanding, needs and preferences, whilst maintaining their dignity and choice
methods of protection against contamination and infection control when handling received impressions and other items which may have been in the mouth, or which are intended to be placed in the mouth; why it is important to do so
the purpose of personal protective equipment
the range of equipment used in the design and manufacture of dental devices; methods of using equipment and materials safely including the use of chemicals and other hazardous substances; methods of storing different equipment and materials safely and securely; methods of cleaning and maintaining different types of equipment and your role in this
the reasons for maintaining records throughout the process and of clearly identifying the products during the manufacturing process
organisational procedures and requirements for the recording of information about incoming work, work in progress and work delivered to clients, and the purpose of this
principles of quality assurance including effective recording and sampling; processes and procedures for quality assurance in your workplace
methods of setting and calibrating equipment and of testing that this is correct
the effects of modifying manufacturers' products to meet laboratory requirements on the physical properties of products and on quality assured products, and the legal implications of poor manufacturing
legal requirements of the contract of employment, confidentiality and employers' regulations
health and safety at work legislation and related procedures and liability; principles of and how to apply, legislation and regulations relating to the manufacturing of devices
the role and obligations of members of the dental team and the regulatory functions of the General Dental Council

Performance Criteria

You must be able to do the following:

analyse the cast and identify:
1. the malocclusion and development problem that are to be corrected
2. the tooth movement and retention that is required to correct the malocclusion
3. the components that are required to achieve the required function
design an appliance which:
1. has the potential to achieve the required function within the patient's mouth
2. incorporates sufficient anchorage and fixation
3. achieves the best balance between function, aesthetics and cost
contact the client without delay if it is not feasible to meet the requirements of the prescription and propose options for the appliance design
evaluate whether the cast needs to be modified to design and manufacture the required removable orthodontic appliance
evaluate the cast and design and decide on the basis of cost, time and function:
1. where pre-formed components can be used within the appliance
2. which components will need to be custom-made
3. any necessary adjustments to component design
identify and select the pre-formed components which are required, make any modifications to them that are necessary to ensure that they will perform the correct function, and confirm that they are fit for purpose
locate casts correctly with the jaw relationship provided by the client
select wire of the correct gauge and material for the required custom-made components, cut it accurately to the required length and straighten it in a manner which avoids unwanted material stress
form components to the required design and size in a manner which minimises the risks of over-work of the material
check components during manufacture to confirm that:
1. they fit to the cast
2. they will not damage surrounding tissues in the mouth
3. the developing appliance is complying with the prescription and design and make any adjustments which are required
position on the cast those components that apply fixation so that they:
1. accurately engage appropriate undercuts
2. provide a firm and stable base for the appliance
accurately position the active and passive components of the appliance in the specified location on the cast and confirm their:
1. fit
2. security
3. compliance with the functional and aesthetic requirements of the prescription
accurately identify active components and areas surrounding teeth and tissue and block them out correctly with the appropriate material
fix components:
1. securely in the required position to the cast to prevent their movement during processing
2. in a manner which is appropriate to the processing method to be used
identify from an examination of the prescription and casts any artificial teeth which are required
select the appropriate type of artificial teeth and modify them to accurately match the patient's:
1. tooth shade
2. tooth size
3. cuspal forms
4. natural dentition
securely attach artificial teeth in the correct position in the baseplate using an appropriate material and produce:
1. an occlusion appropriate to the prescription and natural dentition
2. the required aesthetic appearance
3. balanced articulation whenever this is possible
prepare the cast in a manner appropriate to:
1. the type of baseplate and biteplane material to be applied
2. the processing method to be used
apply appropriate material to the cast to form a baseplate of the required thickness and extension
incorporate within the baseplate any required motivational and decorative material in a position which:
1. allows for maximum visibility
2. will not interfere with the function of the appliance
identify from the cast and design the type, height and extension of biteplane which is necessary for the appliance and articulate casts in a manner appropriate for the construction of this biteplane
form a biteplane of a sufficient thickness of polymeric:
1. to produce the desired movement
2. which are accurate to the degree required in the design
correctly manufacture any two part moulds which are required for prosthetic packing
process appliances using equipment and techniques which are appropriate to:
1. the baseplate material
2. the required strength of finish
remove the appliance from the cast in a manner that minimises the likelihood of damage and remove any excess cast material from the appliances
confirm that processing has been effective in producing a baseplate and biteplane which are:
1. sufficiently hard
2. sufficiently dense
3. free of porosity
confirm that the components are secure within the baseplate and the active components are free to move in the required manner
select methods, materials and equipment for joining components that are appropriate to:
1. the type and materials of the components to be joined
2. the strength and type of join required
identify accurately areas where a soldered joint would not interfere with the function and performance of the component being joined
position components:
1. accurately for the design
2. in a manner that enables the optimum join to be made
calibrate the level and duration of current in spot-welding equipment so that it is correct for the size, thickness and type of material to be joined
confirm that electrodes are free from erosion and take the appropriate action to remedy those that display levels of erosion which are likely to adversely affect the quality of the join
identify accurately areas where a spot-welded join would not interfere with the function and performance of the component, correctly position components and accurately spot-weld them at the correct points to form secure, strong and viable joins
accurately apply flux to those areas where solder is required and block out with anti-flux those where solder is not required so that:
1. there is no incursion of solder
2. the required range of movement is allowed
apply an appropriate heat-protective material to minimise damage to surrounding areas
accurately solder components parts
evaluate each finished join for its:
1. position
2. strength
3. integrity
4. function
5. fitness for purpose
place the appliance on the cast after joining and check that the appliance:
1. fits the cast
2. complies with the prescription
3. will not damage surrounding tissues in the patient's mouth and make any necessary adjustments
remove flux, anti-flux and excess solder once welding and soldering is complete, replace the appliance on the cast and confirm the fit
select methods, materials and equipment for trimming, finishing and polishing conventional removable orthodontic appliances that are appropriate to the type and materials of the components in the appliance
confirm that:
1. the edges of the biteplanes are recognisable against the opposing working cast
2. the active components have the full range of movement required in the prescription
trim and finish the baseplate to the thickness and coverage required
finish and polish metal components to leave smooth surfaces that are free of sharp edges and irregularities and which do not cause damage to the patient's tissues
evaluate the finished appliance and confirm that it:
1. is effective
2. fits the cast
3. is free of defects
4. meets the requirements of the planned design
5. complies with the prescription
6. is fit for purpose
correctly identify the finished appliance with the patient's unique reference and date of production
effectively clean the finished appliance, prepare and package it safely for despatch together with instructions for the patient and client
make complete, accurate and up-to-date records relating to the identification, components and manufacture of the appliance and store the records in the correct location consistent with relevant legislation
provide Statement of Manufacture for the appliance as required under current regulation

Additional Information

This National Occupational Standard was developed by Skills for Health. It replaces DT20 and DT21. This standard links with the following dimension within the NHS Knowledge and Skills Framework (October 2004): Dimension: HWB9 Equipment and devices to meet health and wellbeing needs

OH30 2012 Design and manufacture removable orthodontic appliances
Final version approved September 2012 © copyright Skills For Health,
For competence management tools visit tools.skillsforhealth.org.uk