Received: 27 April 2020
Accepted: 12 August 2020
First Online: 17 August 2020
Ethics approval and consent to participate
: The study was approved by the Medical Ethics Committee of West China Stomatological Hospital of Sichuan University with the approval number: WCHSIRB-ST-2017-85. The administrative department of West China Hospital have approved us to collect data used in our research from the department of radiology of West China Hospital of Stomatology And consent to participate was not applicable.
: Not applicable.
: The authors declare that they have no competing interests.