The aim of this study was to determine the common reasons why a dental professional might request a second opinion on a dental radiograph from a Dental and Maxillofacial (DMF) radiologist. The study was a retrospective analysis of consecutive referrals for an opinion received by post or email by one DMF radiologist based in a UK dental hospital. The study period was from March 2009 to November 2015. Referrals came from a mixture of sources: mainly from general dental practitioners and specialists working in primary care, but with some referrals from hospital-based practitioners. An enormous range in diagnoses were made by the DMF radiologist, but the ten most frequent diagnostic categories contributed 57.5% of the total. Normal anatomy and anatomical variations in normal anatomy made up the largest category. Common dental disease was often diagnosed, but idiopathic osteosclerosis and maxillary antrum pathosis were both frequent reasons for seeking a second opinion. This service evaluation may assist in developing curricula for undergraduates and in designing continuing education courses. It also highlights a service that may avoid unnecessary referrals to hospital specialists but which currently is not commissioned by the NHS.