Digital dental models compare favourably with plaster models

Plaster dental models are useful for diagnosis, teaching, research and from part of the clinical record. However they can break, be lost and require a significant amount of storage space. The development of digital storage offers an alternative to the plaster model.

The aim of this review was to compare the validity of digital dental models produced from laser scanning against measurements from the original physical dental (plaster) models.

Methods

Searches were conducted in the Cochrane, Medline/PubMed, Embase and Lilacs databases. Studies comparing digital models produced from laser scanning of plaster dental models (gold standard) with the original plaster model were considered. Two reviewers independently selected studies and abstracted data. Study quality was assessed using the 14-item quality assessment tool for diagnostic accuracy studies (QUADAS).

Results

16 studies from 7 different countries were included
Study sample ranged form 1-112 models.
The gold (reference) standard in all selected studies was set of a digital caliper (precision = 0.01 mm) measuring plaster models.
Because of study heterogeneity no meta-analysis was conducted.
All 16 studies concluded that precision and accuracy (reliability and validity) of digital models obtained by scanning plaster models are clinically acceptable as a diagnostic tool.

Conclusions

The authors concluded:

All of the included studies demonstrated that with some minor differences, both laser-scanned digital and plaster model measurements are valid.

Comments

This review focused on intra-arch measurements. Many of the QUADAS criteria were not met for the included studies. One of the key issues with the quality of this review was the lack of clarity in the original studies over whether the reference (gold standard) tests were undertaken without knowledge of the results of the index test. Most of the studies reported some statistical differences between some of the digital and plaster model measurement.

In the discussion, the authors note that caliper measurements also suffer with some error and consider that digital scanning provides an alternative to maintaining plaster models long term as the original dimensions in the new format are maintained.