Dental arch relationships on three-dimensional digital study models and conventional plaster study models for patients with unilateral cleft lip and palate.

Objective: To determine if three-dimensional (3D) digital study models could replace plaster study models for the evaluation of dental arch relationships for patients with unilateral cleft lip and palate.

Design: Observational study involving plaster study models from a records archive

Setting: U.K. National Health Service.

Patients, Participants: Thirty sets of study models of 5-year-old patients with unilateral cleft lip and palate were identified and scanned to produce 3D digital study models by ESM Digital Solutions Ltd. (Swords, Co. Dublin, Ireland) using an R250 Orthodontic Study Model Scanner (3Shape A/S, Copenhagen, Denmark).

Interventions: None.

Main Outcome Measure(s): The plaster and 3D digital study models were scored using the 5-year-olds' and modified Huddart Bodenham indices and analyzed using the Friedman test (p < .05) and two-way ANOVA, respectively. Intra-observer and interobserver reproducibility were calculated from the 5-year-olds' index data using the weighted kappa statistic for both the plaster and 3D digital models.

Results: Intra-observer and interobserver reproducibility were good (0.62 to 0.83 and 0.64 to 0.78, respectively). There were no statistically significant differences between the scores for the 3D digital study models when compared to the plaster study models for either the 5-year-olds' index (p ?=? .12) or for the modified Huddart Bodenham index (p ?=? .506).

Conclusions: Three-dimensional digital models are a valid alternative to traditional plaster study models for the evaluation of dental arch relationships in patients with unilateral cleft lip and palate.