Highlighted review: Final-impression techniques and materials for making complete and removable partial dentures

Srinivasan Jayaraman, Balendra P Singh, Balasubramanian Ramanathan, Murukan Pazhaniappan Pillai, Laura MacDonald, Richard Kirubakaran 

Plain language summary: Techniques and materials for final impressions when making complete and partial removable dentures

Review question
In this review, conducted through Cochrane Oral Health, our aim was to evaluate which technique and material should be used for the final impression when making complete and partial removable dentures, to increase the quality of the denture, and improve oral health-related quality of life for the individual.

Background
It is common for elderly people to have lost some, or all of their teeth (edentulism). This has a significant impact on their quality of life. There are several steps to making complete and removable partial dentures.

The final impression is a very important step for ensuring the quality of the denture in terms of satisfaction, comfort, stability of the denture, and chewing ability. There are a number of different techniques and materials used for making the final impression for complete dentures or removable partial dentures. There is no consensus on which are the best.

Study characteristics
The evidence in this review is current to 22 November 2017. We found eight studies with a total of 485 participants for complete dentures, and one study with 72 participants for removable partial dentures. The participants ranged from 45 to 75 years old, and had been without their teeth for 10 to 35 years.

The studies compared different materials used to make the final impression for dentures (alginate, zinc-oxide eugenol, wax, and addtional silicone, polysulfide or polyether) and different techniques for making the final impression (open-mouth versus closed-mouth, single-stage versus two stage-two step), or both.

Key results
For most comparisons and outcomes, there was no evidence of a clear difference between the techniques or materials compared.

Very low quality-evidence from one study (10 participants) suggested that making dentures with an additional silicone elastomer biofunctional prosthetic required fewer adjustments than conventional methods.

Low-quality evidence from another study (144 participants) suggested that complete dentures made with silicone elastomer in a two stage–two step final impression, may be better than those made with alginate, in terms of oral health-related quality of life, stability of the denture, and chewing efficiency.

With the limited evidence available, we are unable to draw any conclusions about the best impression techniques and materials for complete and partial removable dentures. There is a need for further research in this area.

Quality of the evidence
The quality of the evidence base overall is low to very low. Only one or two studies assessed each intervention and comparison, and most of the studies were at high risk of bias. Many of the studies did not measure our key outcomes. For both complete and partial removable dentures, we conclude that we have no reliable findings.

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Citation: Jayaraman S, Singh BP, Ramanathan B, Pazhaniappan Pillai M, MacDonald L, Kirubakaran R. Final-impression techniques and materials for making complete and removable partial dentures. Cochrane Database of Systematic Reviews 2018, Issue 4. Art. No.: CD012256. DOI: 10.1002/14651858.CD012256.pub2.