41. Full dental arch impressions. Bite registration.

Full or Complete dental impressions:

3 types of techniques are used for full dental impressions:

Full or Complete dental impressions:

- This impression captures all teeth and surrounding tissues inside the oral cavity - They provide full details on existing structures which is widely used in clinical situations - Used for implant supported restorations - Complete removable dentures / removable partial dentures - Dental bridges

3 Distinct impressions are taken: 1. Upper arch impression 2. Lower arch impression 3. Occlusion impression OR bite registration

3 types of techniques are used for full dental impressions:": one step and 2 step (different to the one step from partial dentures which has two viscosities aka heavy/light fluid. that one is used bc its more comfortable for the patient)

1. One-Step Technique

• Uses only one impression material

• Lower accuracy (low fidelity)

• Fast and simple procedure

• Common materials:

  • Putty silicones

  • Alginates

Steps:

• Select stock impression tray to fit the dental arch

• Mix and place material into the tray

• Position tray on the dental arch and press down

• Wait for the material to set

• Remove and rinse the impression

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2. Two-Step Technique (Wash Technique)

• Uses two materials: putty and fluid silicone

• High accuracy (high fidelity)

• Materials used:

  • Rigid putty

  • Flowable (fluid) silicone

Steps:

1. Take the first impression with the rigid putty material

2. Allow it to set — this becomes a custom tray

3. (Optional) Place a retraction cord around the gums to expose tooth margins

4. Fill the set putty impression with fluid silicone

5. Re-seat the filled impression tray on the dental arch

6. Let the fluid material capture fine details and setures all details and once it sets it gains elastic consistency

3. Custom tray technique

Bite registration:

• -  Used to find the dental occlusion of the patient

• -  More specifically the relationship between the upper and lower jaw

  Importance:

• -  To identify the relationship so that the designed restoration fits in occlusion without any preliminary contacts

• -  Bite registration is analysed in 2 circumstances: Static and Dynamic occlusion Dynamic occlusion refers to: Static occlusion refers to:

Dynamic occlusion refers to:

when the jaw position is moving

Static occlusion refers to:

max intercuspation, closed, important for large restoration

- When the jaw position is moving

- Movements can be forward,

backward and sideways

- When the jaw position is closed and stationary

- This is when the upper and lower teeth are in maximal occlusion (maximal intercuspal contact)

- For large restorations these relationships are the most important

procedure of bite reg

1. Bite registration is done with a very rigid impression material

2. A putty base and a catalyst are mixed with a catalyst (pre-mixed syringe-able material

   can also be used)

3. Prepared material is placed on the occlusal side of the entire arch (upper or lower)

4. The patient must bite in the correct occlusion

5. The material sets after 1 or 2 minutes