Reline, rebase, repair and modify removable prostheses

This standard is about the relining, rebasing, repair and modification of removable prostheses.

Relining and rebasing involves adding further polymeric material to the existing prosthesis to achieve the required fit.

This evaluation may be undertaken directly with the individual or without the individual being present. If an effective repair is possible without the need to refer to the dentist for an impression, you will need to discuss the cost of the repair and obtain the individual's consent for the repair to proceed.

The term 'client' is used to mean the member of the oral health care team who has prescribed the relining, rebasing, repair or modification of the prosthesis. Clients may be external to the organisation (such as other laboratories, dental practitioners, training schools) or internal (within a dental hospital). The individual is the one for whom the custom-made prosthesis has been made.

The design and manufacturing process of dental prosthesis may be carried out in a regulated dental laboratory within a variety of settings.

Users of this standard will need to ensure that practice reflects up to date information, policies and regulations.

1. confirm identity of the individual in accordance with workplace procedures
2. gain valid, informed consent from the individual in accordance with workplace procedures
3. communicate with the relevant others at a pace, in a manner and at a level appropriate to the individual's understanding, preferences and needs
4. provide support to the individual and ensure health and safety measures are implemented at all times
5. ensure the received impression has been effectively cleaned
6. pour the cast material into the impression and produce a cast that is free from voids or other visible defects
7. index to the cast in order to rebase or reline
8. remove the impression in a manner that maintains the integrity of the cast and minimises disturbance to the teeth
9. remove an appropriate thickness of material from the fitting surface of the prosthesis and shape the prosthesis suitably to produce sufficient bonding for the new material
10. evaluate the occlusal vertical dimension of the cast against the index and make any necessary adjustments
11. apply releasing agent to mating surfaces to facilitate effective separation
12. For repairs assess the reassembled fragments and make a decision as to whether:
    • to request an impression with the reassembled prosthesis in place
    • a new impression is needed to enable the prosthesis to be repaired
    • the damaged prosthesis is beyond repair
13. repair the removable prosthesis, form into the correct relationship those fragments of the removable prosthesis which it is possible to reassemble and fix them together
14. separate the cast from the impression, reassemble fragments or make addition to the prosthesis
15. release the repaired prosthesis from the moulds without damaging it following processing and trim any excess material
16. clean the prosthesis fragments and prepare for joining
17. join components at the correct points to form secure, strong and viable joints
18. survey the cast to identify the position and size of undercuts, determine an appropriate path of insertion for the planned prosthesis and block out any unsuitable undercuts
19. add extra mechanical retention to the prosthesis if this is required and prepare the surfaces appropriately for the modification
20. modify the prosthesis, select and prepare, or remake components to change the nature and construction of the removable prosthesis to conform with the individual's natural dentition
21. place additional or replacement polymeric or metallic components in the correct place on the prosthesis and fix them securely
22. mix resin and monomer and process to manufacturers' guidelines
23. apply polymeric resin using the correct technique to the required shape and thickness to ensure fit
24. fit the trimmed and polished prosthesis to the cast and reposition the casts on an appropriate articulator where necessary
25. assess the articulated prosthesis, confirm that the occlusion is appropriate to the prescription and the individual's natural dentition, make any necessary adjustments to maintain the original vertical dimension of the occlusion
26. evaluate the finished prosthesis to ensure it is fit for purpose
27. clean and finish the restoration, prepare and package it safely for dispatch together with instructions for the individual and client
28. dispose of waste in accordance with all relevant legislation, guidelines, and workplace procedures
29. complete and store all documentation in accordance with relevant legislation, guidelines, and workplace procedures

1. how to communicate with the individual and relevant others at a pace, manner and level appropriate to their understanding, preferences and needs.
2. the importance of applying standard infection control precautions and the potential consequences of poor practice
3. the principles, practice and procedures associated with informed consent
4. skeletal anatomy, tooth morphology, orofacial musculature and temporomandibular joint function and movement
5. the classification, aetiology, including oral cavity disorders and diseases and the physiological effects of malocclusions.
6. the physiological and pathological changes associated with ageing process and trauma related to the oral environment
7. the importance of retention of the periodontal ligament and the changes in proprioception due to loss of periodontal ligament
8. the role of removable prostheses in the restoration and maintenance of:
   • tissue support
   • aesthetics
   • phonetics
   • function of occlusion and the temporomandibular joint
9. the importance of restoring and maintaining the occlusal vertical dimension
10. the benefits and restrictions of immediate tooth replacement in the provision of removable prostheses
11. the benefits and restrictions of retaining root structures in the provision of removable prostheses
12. the use and need for transitional removable prostheses
13. the purpose and use of resilient liners and tissue conditioners
14. the design limitations of large anterior undercuts and pre-existing dental conditions
15. the principles and practice of:
    • retention and stability
    • aesthetics and phonetics
    • articulation
16. the principles of partial removable prosthesis design
17. methods of modifying, maintaining and repairing removable prostheses
18. the methods used for relining and rebasing removable prostheses
19. the range of equipment used in the design and manufacture of dental devices
20. the classification and sub-classification of materials on the basis of chemical composition and internal structure
21. the mechanical, physical, thermal, chemical and biological properties of materials
22. the purpose of different products used for cast and mould manufacture
23. the purpose of different materials used in the manufacture of removable prostheses
24. legal and physical implications of modifying manufacturer products and ensuring quality assurance
25. how to clean and finish the restoration, prepare and package it safely for dispatch together with instructions for the individual and client
26. different methods of waste disposal and how to apply these
27. the importance of updating documentation and storing individuals records safely and securely