COMPARISON OF 2-D CALCULATIONS FROM PERIAPICAL AND OCCLUSAL RADIOGRAPHS VERSUS 3-D CALCULATIONS FROM CAT-SCANS IN DETERMINING BONE SUPPORT FOR CLEFT-ADJACENT TEETH FOLLOWING EARLY ALVEOLAR BONE-GRAFTS

Objective: This investigation was conducted to determine the agreement between three-dimensional (3-D) calculations from CAT scans and two-d imensional (2D) calculations from standard dental radiographs in evalu ating bone support for cleft-adjacent teeth after primary bone graftin g, Design: This retrospective study utilized CAT scans and dental radi ographs taken of the alveolar cleft in patients an average of 11 years after primary bone grafting, Setting: The subjects were patients trea ted by the Cleft Palate Team at Children's Memorial Hospital and Loyol a University Medical Center, Chicago, Illinois. Patients: Fourteen UCL P patients (9 males, 5 females) agreed to participate in this study by undergoing CAT scan assessment of their alveolar cleft sites, They al so had to have periapical or occlusal radiographs of the grafted cleft site taken within 6 months of the CAT scan, Interventions: Alt patien ts underwent primary lip repair, placement of a passive palatal plate, primary alveolar bone grafting (mean age 6.4 months), and palatoplast y before 1 year of age. Major tooth movement through final orthodontic s was completed by the time of the radiographic assessment. Main Outco me Measures: CAT scan sections were reformatted and reconstructed to t hree-dimensionally calculate the percentage of root covered by bone su pport for the 15 teeth adjacent to the grafted cleft sites. Dental rad iographs of the same teeth were also traced and digitized. Percentages of root supported by bone were also established using the dental radi ographs by dividing the amount of root covered by bone, by the anatomi c root length. Results: A paired, two-sample t test revealed no signif icant differences between the two methods of assessment, while linear regression showed a statistically significant correlation between the CAT scan assessment and the percentages found on the radiographs. Conc lusions: Routine dental radiographs were able to estimate the total 3- D bone support for the roots of cleft adjacent teeth as determined by CAT scan to a statistically significant degree when groups where compa red, The clinical significance for evaluation of individual cases was less impressive with a wide range of variability and a level of agreem ent that required acceptance of differences up to 25%.