The effect of the lateral cephalometric radiograph on orthodontists' diagnosis and treatment decisions: a double-blind, randomised controlled trial

Aims: To evaluate the influence of the lateral cephalometric radiograph on orthodontists' diagnosis and treatment planning decisions. Methods: Five patients with full pre-treatment records were selected to represent a spectrum of malocclusions. The records were provided in a web-based questionnaire emailed to 510 Australian registered orthodontists. Participants were asked to formulate a diagnosis and treatment plan for a randomised patient case. The control group received a lateral cephalometric radiograph whilst the intervention group did not. The two groups' diagnostic accuracy was determined by a comparison with the formative diagnoses determined by five senior academic orthodontists. Their diagnosis and treatment planning decisions were also compared. Results: A comparison of the orthodontists' diagnoses revealed that the lateral cephalometric radiograph did not lead to an increase in the assessment accuracy of dental (p = 0.7971 and skeletal (p = 0.273) relationships. Further analysis using logistic regression showed that the orthodontists' years of experience did not influence the accuracy of skeletal diagnosis (p = 0.177). A comparison between the orthodontists' dental (p = 0.689) and skeletal (p = 0.321) determinations did not significantly differ between the two groups. An assessment of the vertical growth pattern (p = 0.656) was also unaffected by the omission of the lateral cephalometric radiograph. When the two groups considered treatment planning options, there were no statistically significant differences related to the treatment options of growth modification (p = 0.720), orthognathic surgery (p = 0.101), and/or an extraction decision (p = 0.840). Conclusion: Lateral cephalometric radiographs did not significantly influence orthodontists' diagnosis. There was also little evidence to demonstrate the radiograph's efficacy in treatment planning cases with no skeletal discrepancy or no significant labiolingual incisor movement planned.