Comparisons of effect and safety of MRI of head and neck in patients with fixed partial dentures made by different materials / 吉林大学学报(医学版)

ABSTRACT

Objective:To make the fixed partial dentures with different materials and the magnetic resonance imaging (MRI)examination of head and neck was carried out to investigate the effects of fixed partial dentures on MRI.Methods:A qualified volunteer was recruited,who was conventionally restored using fixed partial denture. Co-Cr alloy,Au-Pt alloy and Zirconia were chosen as the inner crown materials,respectively.Three kinds of fixed partial dentures were put into the mouth of patient,and 2 kinds of MRI scan sequences (T1-TSE and T2-TSE) were performed.The scanning images without restorations were used as controls.The change of shape,image signal and involving layers of artifacts of different materials in three groups were observed.The maximum diameter of artifact of three materials in coronal, sagittal and axial images were detected. The safeties of fixed partial dentures were observed. Results: The artifacts were found in all the restorations and showed the changes of strengthen and weaken of the signal and the changs of shapes of images.The range of artifacts was the largest in the involved central plane and varied in sagittal,coronal and axial images. The number of involving layers of artifacts in Co-Cr alloy group was significantly more than those in Au-Pt alloy and Zirconia groups;the artifacts were limited in the repaired lateral maxillofacial region without the cervical spine and head region involvement.The artifacts in Co-Cr alloy group involved or slightly involved in all adjacent tissues,and the artifacts in Au-Pt alloy and Zirconia groups only slightly affected the mandibular teeth,lingual muscles and maxillary crowns.The maximum diameter of artifacts in Co-Cr alloy group was larger than those in Au-Pt alloy group and Zirconia group (P <0.05). No displacement was found in the prosthesis,and the patient had no discomfort.Conclusion:The artifact of the fixed partial denture can be seen in MRI examination.Co-Cr alloy or zirconia can significantly reduce the effect of artifact.Fixed adhesive prosthesis in mouth does not affect the safety of MRI examination.