Evaluation of precision and trueness of intraoral scanners for newborns with cleft lip and palate: 3D analysis of digital models.

backgroundChildren born with cleft lip and palate (CLP) require intensive interdisciplinary care from birth onward. Intraoral scanners (IOS) have emerged as a promising alternative for neonatal maxillary data acquisition. This study evaluated the precision and trueness of five commonly used IOS using a standardized landmark-based methodology complemented by full-surface deviation analysis, applied to neonatal maxillary models with increasing morphological complexity.

methodsThree neonatal plaster casts were digitized: An edentulous maxilla without cleft, a unilateral and a bilateral cleft maxilla. Ten pyramidal landmarks defining five transversal distances were constructed along the alveolar ridge. These resulting digital master models (DMM) were 3D-printed (Formlabs Form 2, 25 μm) and their dimensional fidelity independently verified by digital caliper (± 0.01 mm). Each printed model was scanned ten times by the same operator using Primescan, CS3600, Trios 3, iTero Element 2 and Medit i500. Linear trueness and precision were quantified in Rhinoceros 3D. Full-surface trueness was assessed in Geomagic Control 3D using a standardized alignment protocol. Statistical analysis was performed using the Kruskal-Wallis test and Mann-Whitney U post-hoc tests (p < 0.05).

resultsTrueness varied between IOS and depended on the combination of device and cleft morphology. Mean signed linear deviations were minimal in the non-cleft model (all scanners within ± 0.03 mm) and reached - 0.147 mm for Medit in the bilateral cleft model, where Primescan and Trios remained essentially unbiased in the non-cleft and bilateral cleft models. Between-scanner differences were significant in both cleft models (p < 0.001). Intra-scanner reliability, an aspect of precision, ranged from ICC 0.832 to 1.000. Full-surface trueness differed significantly between scanners in all three models (p < 0.01). Mean RMS deviations remained below 0.07 mm for four of the five devices in every model, whereas iTero reached 0.224 mm in the bilateral cleft model. Compared with the non-cleft model, in-tolerance percentages decreased in both cleft models, most markedly in posterior and undercut regions.

conclusionUnder in-vitro conditions, all IOS digitized neonatal maxillary anatomy with high technical accuracy. Trueness and precision depended on the combination of device and cleft morphology rather than on morphological complexity alone, but all IOS captured the relevant morphological features. Clinical feasibility in neonates was not assessed and remains to be established in in-vivo studies. CLINICAL TRIAL NUMBER: Not applicable.