HLTDET002
Construct custom impression trays


Application

This unit of competency describes the skills and knowledge required to construct special trays to accurately record oral tissues.

This unit applies to work in dental technology.

The skills in this unit must be applied in accordance with Commonwealth and State/Territory legislation, Australian/New Zealand Standards and industry codes of practice.


Elements and Performance Criteria

ELEMENT

PERFORMANCE CRITERIA

Elements define the essential outcomes

Performance criteria describe the performance needed to demonstrate achievement of the element.

1. Prepare model

1.1 Read and interpret the work order

1.2 Block out undesirable undercuts

1.3 Design the custom tray for the patient’s dentition and the intended impression material and technique

1.4 Apply spacer material when required

2. Select and prepare materials

2.1 Select custom tray materials in accordance with the work order

2.2 Prepare equipment for processing

2.3 Provide appropriate mixing vessels and templates when required

3. Construct custom impression tray

3.1 Apply appropriate separating medium in accordance with manufacturer’s instructions

3.2 Mix or manipulate materials in accordance with the manufacturers’ instructions

3.3 Adapt tray material to the model to the pre-determined peripheral outline

3.4 Construct handle and attach according to operator requirements

3.5 Process custom tray using the correct method for the correct material

3.6 Separate the tray from the model in a manner that prevents damage and remove spacer material

3.7 Trim the outline of the tray to shape

4. Finish custom impression tray

4.1 Smooth and refine the peripheries, handle and other surfaces of the tray

4.2 Decontaminate the custom impression tray according to infection control guidelines

4.3 Dry the custom tray and place in a sealed container for dispatch

Evidence of Performance

The candidate must show evidence of the ability to complete tasks outlined in elements and performance criteria of this unit, manage tasks and manage contingencies in the context of the job role. There must be evidence that the candidate has:

• read and correctly interpreted 4 work orders

• used standard precautions and safe work practices to fabricate custom trays, using a range of materials, for 4 different dentitions with desirable properties and design features including one each of the following (must be a combination of maxillary and mandibular arches):

- full dentition

- edentulous

- partial dentition including

o bounded saddle

o free end saddle

• critically evaluated the 4 custom impression trays produced to meet technical laboratory and clinician requirements.


Evidence of Knowledge

The candidate must be able to demonstrate essential knowledge required to effectively complete tasks outlined in elements and performance criteria of this unit, manage tasks and manage contingencies in the context of the work role. This includes knowledge of:

• Australian/New Zealand Standards, workplace health and safety (WHS) policies, current Dental Board of Australia guidelines on infection control, Commonwealth and State/Territory legislation requirements and organisation policies relating to dental laboratory work

• Fundamental oral anatomy including:

- dentition – arrangement of the teeth, naming and coding of teeth

- structures of the oral cavity – hard and soft palate, lateral and posterior borders of the oral cavity, tongue and floor of the mouth

- teeth form and function

• properties of custom tray materials including:

- acrylic resins

- light-cured composite

• rationale for using space filling materials

• desirable properties and design features of custom impression trays including:

- a design that holds the impression material in the correct position in the mouth

- a design that supports the lips and cheeks so that the functional depth and shape of the sulcus is recorded

- a design that allows for positioning of the handle to avoid the lip during impression taking

- rigidity, strength, dimensional stability and smoothness

- spacing to permit the correct thickness of the impression material to be used.


Assessment Conditions

Skills must have been demonstrated in a dental laboratory workplace or in a simulated dental laboratory environment that reflects workplace laboratory conditions. The following conditions must be met for this unit:

• use of suitable facilities, equipment and resources including:

- access to work order

- Dental Board of Australia guidelines on infection control on which the candidate bases the planning process

- laboratory safety manuals and procedures in line with relevant Commonwealth and State/Territory legislation

- WHS policies on which the candidate bases the planning process.

Assessors must satisfy the Standards for Registered Training Organisations (RTOs) 2015/AQTF mandatory competency requirements for assessors.


Foundation Skills

The Foundation Skills describe those required skills (language, literacy, numeracy and employment skills) that are essential to performance.

Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.