Objectives: To evaluate the accuracy of panoramic radiography (PR) in assessing the dimensions of mandibular lesions.
Methods: One hundred and fifteen cases exhibiting radiolucent lesions in the mandibular premolar, molar or ramus area were selected retrospectively. They were divided into four types: cyst with sclerotic margin (Type I); cyst without sclerotic margin (Type II); ameloblastoma (Type III); or squamous cell carcinoma (Type IV). Maximum mesiodistal length and superoinferior height were measured on PR (Lpmax and Hpmax, respectively) and on CT (Lcmax and Hcmax, respectively) and the results were compared.
Results: Correlation coefficients between Lpmax and Lcmax and between Hpmax and Hcmax were high for Type I, II and III lesions but were significantly lower for Type IV lesions. Regression coefficients between Lpmax and Lcmax and between Hpmax and Hcmax were indistinguishable from 1.0 for all types of lesions. The mean relative difference between Lpmax and Lcmax varied from 1.2% to 8.2%. The difference was only -0.3% for larger lesions of combined Types I and II. The mean relative difference between Hpmax and Hcmax varied from--3.5% to 1.1% depending on the type of lesions.
Conclusion: PR is accurate for assessing the dimensions of radiolucent lesions in the posterior mandible when the margins are well defined.