Comparative Study Of Commonly Dental Prosthesis And Magnetic Resonance Imaging Artifact

Because of its high sensitivity about soft tissue morphology, anatomy and pathology change, MRI (magnetic response imaging) has been widely used. But the inspection method, which has great diagnostic value, is taboo for some patients with metal implants. However, because of its excellent mechanical properties, low cost and biocompatibility, metal materials are widely used in the modern dental prosthetics area. When the head is scanned by MRI, the metal prosthesis in mouth affects the uniformity of the magnetic field, which can result susceptibility artifact around the metal prosthesis, and interfere with the diseases’diagnosis. Therefore, reducing and avoiding metal artifacts, or choosing materials which have small or none metal artifacts were the problem to be solved.Objective:Investigate the different effect of different materials, number and location of common dental prosthesis on human cranial magnetic resonance imaging, and thus to provide reference for clinical selection of prosthesis material.Methods:Put swaged crown, nickel-chromium alloys PFM, cobalt-chromium alloys PFM, titanium porcelain crowns, zirconia all-ceramic crowns and the corresponding three-unit fixed bridge of different materials in the mouth of the same volunteer; Then, to scan under T1 flair, using the associated software to measure maximum artifact layer’ length and height; last, analysis the measurement results by the statistical method.Results:1. swaged crown and the other three metal-ceramic crown and corresponding bridge will produce scattered artifacts, while zirconia all-ceramic crown had no effect on the magnetic resonance imaging;2. The relationship between artifacts and prosthesis materials. zirconia crown had no effect, while the titanium crown<Ni-Cr porcelain crown<Co-Cr porcelain crown <swaged crown, P<0.05, significant difference having statistically significant;3. The relationship between artifacts and prosthesis position. The artifacts caused by various materials single crown in anterior and posterior region had not significantly different, P> 0.05, having no statistically significant;4. The shape of artifact had relationship with the prosthesis’ shape. former single crown’ height is greater than the width of artifacts, P<0.05, significant difference having statistically significant; posterior single crown width is greater than the height of the artifacts, P<0.05, significant difference having statistically significant;5. The relationship between artifacts and the number of prosthesis. Various materials in the same position, the greater the number, the greater the scope of artifacts, P<0.05, significant difference having statistically significant.Conclusions:1. Among oral fixed prosthesis materials, the titanium crown, Ni-Cr porcelain crown, Co-Cr porcelain crown and other metal materials can affect head MRI scanning, zirconia all-ceramic crowns had no effect on magnetic resonance imaging, so as to avoid the MRI artifacts, zirconia all-ceramic crown is the preferred material.2. Among several kinds of commonly used restorative materials, the same position and the number of the restoration produced MRI of different artifacts. The artifact area of titanium crown< Ni-Cr porcelain crown< Co-Cr porcelain crown< swaged crown. Therefore,choosing restoration material reasonably can appropriately reduce artifacts’ effect.3. The restoration of same material but different location can result little difference in MRI artifacts. But the artifacts’ form is related to the restoration’s form. Artifacts’ height is greater than width, which are produced by single crown in the front teeth. By contrast, the tooth crown artifact’s width is greater than the height in back teeth. The size of the artifacts is also associated with the number of the restoration, the number is greater,the area of the artifact is bigger.