Long-term secondary alveolar bone graft evaluation in complete clefts using a new radiographic scale and determining optimal graft assessment timing

Purpose. This study evaluates the effect of length of follow-up on alveolar cleft bone graft outcomes of two cleft lip and palate treatment centers. The Americleft SWAG scale for assessing graft outcomes was also evaluated for reliability and validity.;Methods. 164 occlusal radiographs representing short- (T1) and long-term (T2) follow-ups from 82 consecutively grafted patients (43 from Center 1, 39 from Center 2) were rated using the SWAG scale from 0 (failed graft) to 6 (ideal). Mean grafting age was 9y10m (9y7m Center 1, 10y1m Center 2). Average T1 was 11y1m in the mixed dentition, and 1y3m post-graft (10y10m Center 1, 11y3m Center 2). T2 was 17y7m in permanent dentition, and 7y9m post-graft (20y2m Center 1, 14y6m Center 2). Six trained/calibrated raters scored each radiograph twice. Rating for each graft at T1 and T2 was the average of 12 ratings. Reliability was calculated at T1 and T2 using weighted Kappa. Paired t-tests (p<.05) were used to test mean T1 and T2 differences for each Center. Correlation tested the relationship between T1 and T2 ratings. Linear regression was used to determine possible factors that might contribute to graft rating changes.;Results. Paired t-test failed to find a statistical difference between T1 and T2 scores for either Center. There was a significant correlation between ratings at T1 and T2 (r=0.68). Twenty-seven patients' ratings became better or worse by more than one point. Linear regression identified several treatment cofactors of interest. There was a greater chance of bone graft score improvement with completion of canine eruption and canine substitution for missing lateral incisors. Mean inter- and intra-rater Kappa measurements were good (inter-rater: overall=0.705), (intra-rater: overall=0.788). Mean Center 1 scores were significantly better than Center 2 at both T1 (5.21 vs. 3.19) and T2 (5.17 vs. 3.43).;Conclusions. Short-term follow-up ratings of graft outcomes of groups of patients from different centers identified significant differences between centers that did not change over time with similar differences identified at short-term and long-term. The rating system was reliable in the mixed and permanent dentitions. Outcome comparisons might optimally be made effectively as early as one year post-grafting.