The objective of the current study was to evaluate intra- and interobserver bone volume measurements and effect of orientation on the reliability of bone volume evaluation in as-acquired vis-à-vis oriented cone beam computed tomography scans using Osirix software and possible correlation between gender, age, and bone volume required. For this, 31 cone beam computed tomography (CBCT) scans of 14 girls and 17 boys (aged 9-13) with unilateral cleft lip and/or palate who met the inclusion criteria were analyzed. Efficacy and reliability of third party software Osirix for bone volume calculation was assessed using as acquired and oriented volumes by three specialists (a radiologist, an orthodontist, and an oral maxillofacial surgeon). The dataset and readings were anonymized to prevent any bias. Two-way mixed model analysis on as-acquired and oriented observations exhibited intra-class coefficient (ICC) values ≥ 0.90. Wilcoxon signed rank test (p = 0.10) and Kruskal-Wallis ANOVA (p = 0.46) indicated that although a clinical difference in volume assessment was seen between as-acquired and oriented observations (inter-observer and intra-observer), it was statistically insignificant. Spearman's bi-variate correlation analysis revealed a significant relation between the type (side) of cleft and bone volume required to fill the defect (p < 0.05). Although there was clinical difference in bone volume measurement by the three observers, it was insignificant statistically. Clefts on the left side in the patients had significantly more bone required than the right side, whereas age and gender had no relation with bone needed to fill the defect. OsiriX software provided good reliability in measurements of bone volume.
Keywords: CBCT; Osirix; SABG; alveolar bone grafting; bone volume calculation; cleft lip and palate; unilateral cleft.