The Effect of Earlier Bone Grafting, Prior to Orthodontic Treatment, on SWAG Ratings of Graft Outcomes

Abstract

Objective: To compare the outcomes between 2 groups of patients with complete clefts treated with early secondary alveolar bone grafting (ABG) at 2 centers (5-7 years, before orthodontic intervention) and to a third group of patients treated at one of those centers (center 1) who had received later secondary ABG (8-10 years, after orthodontic intervention). Design: Blind retrospective analysis of cleft site radiographs using Americleft Standardized Way to Assess Grafts (SWAG) scale. Patients: A total of 99 patients with complete clefts from 2 North American cleft/craniofacial centers. Interventions: Secondary ABG representing 2 protocols: early grafting at a mean age of 6.6 years prior to any orthodontic intervention, and later grafting at a mean age of 10.2 years following pregrafting orthodontic intervention. Main Outcome Measures: Using occlusal radiographs, the SWAG scale from 0 (failed graft) to 6 (ideal) was used. Six trained, calibrated raters scored each radiograph twice, with the average of the 2 ratings used as the final score. Reliability was assessed using the weighted κ statistic. The significance of differences between groups was determined using the Kruskal-Wallis test and Dunn test for pairwise comparisons. Results: Inter-rater reliability of SWAG method was good (0.631). Intra-rater reliability was excellent (0.817). There was a tendency for improved total graft outcome in the early grafted group from center 1 compared to the later grafted group with improvement being significantly different in only the coronal third of the early, preorthodontic grafted group. However, the difference was not statistically significant for the graft overall.