Intra-Oral Three Dimensional Scanning for Assessment of Surgical Outcome in Patients with Unilateral Cleft Lip and Palate

Abstract

Background: Cleft lip and palate is the most common congenital craniofacial anomaly. Orofacial clefting (OFC) presents as a heterogeneous group of disorders affecting the lips and oral cavity. Treatment involves a multidisciplinary team working with a high burden of care.Evidence is lacking regarding the optimum timing of lip and palate repair. Audit records are part of clinical governance, collected to monitor quality of care, but they can also be used for research purposes to generate an evidence base for best treatment protocol. Surgical outcome indices can be scored from audit records. The World Health Organisation (WHO) recommends study models to be taken pre-surgery and at 5, 10 and 18 years of age. The impression-taking process can be upsetting to the child and result in a failure to comply (Clark et al., 2007).Plaster study models can be scanned to create indirect three dimensional (3D) digital models and dental arches can be scanned directly using an intra-oral 3D scanner. The latter technique eliminates the need for impression taking but has not previously been investigated in cleft care.Aims: This prospective study aimed to examine the reliability of intra-oral 3D scans as an alternative to study models in assessment of dental arch relationships in a sample of 5-21 year olds with unilateral cleft lip and palate (UCLP).A secondary aim was to obtain patient and parent/carer feedback regarding acceptability of dental impressions and intra-oral 3D scans.Hypotheses (null): There is no difference in the reliability of scoring dental arch relationships using the GOSLON and MHB indices on plaster and digital 3D study models.There is no difference in patient / carer acceptability of routine dental impressions and intra-oral 3D scanning.Materials and Methods: Forty-six patients with UCLP attended the data collection clinic. Three patients withdrew as they did not wish to have routine dental impressions taken therefore 43 underwent routine dental impressions and intra-oral scanning [Trios® Digital Impressions Scanner ϵ (3Shape A/S, Copenhagen, Denmark)] of their dental arches. Once cast the plaster models were scanned by an orthodontic 3D model scanner [R700 Orthodontic Study Model Scannerϵ (3Shape A/S, Copenhagen, Denmark)] to create indirect digital study models. Three examiners scored the plaster, direct and indirect study models using the Great Ormond Street, London and Oslo, Norway (GOSLON) Yardstick and modified Huddart Bodenham (MHB) indices on 2 occasions, one month apart. All 43 participants and 32 accompanying parents/carers completed a simple questionnaire regarding the acceptability of the dental impressions and intra-oral scans.Cronbach's Alpha was used to determine reliability scoring for each study model medium using the GOSLON scores. Inter-examiner reliability was assessed using Bland Altman plots for the MHB data with the data being tested for each model medium using a one-sample T-test (P<0.05). The questionnaire data was statistically tested using Wilcoxon signed ranks tests (p<0.05).Results: All examiners and mediums of study models achieved an intra-examiner reliability score greater than 0.987, deemed to be above the acceptable range. The direct digital scans demonstrated superior inter-examiner reliability to indirect digital and plaster models but differences were not statistically significantly different (p>0.05).Feedback from the questionnaire indicated that participants strongly preferred the 3D scan (p=0. 00018). There was no significant difference in regards their perception of the time required (p˃0.05). The parents/carers preferred their child’s experiences of the 3D scanner compared to the routine impressions (p =0.003) and the perceived time required (p=0.030).Conclusions: 1.Reliability of GOSLON and MHB scoring using intra-oral three dimensional (3D) scans was superior to both plaster and indirect 3D digital models.2.Subjects with UCLP and their parent/carer preferred the experience of the intra-oral 3D scan in comparison to routine dental impressions.3.This study supports the replacement of conventional impressions with intra-oral 3D scans in longitudinal evaluations of the outcomes of cleft care.

Date of Award	2015
Original language	English
Sponsors	Scottish Association for Cleft Lip & Palate
Supervisor	Peter Mossey (Supervisor) & Grant McIntyre (Supervisor)