Comparative study on computed orthopantomography and film radiographic techniques in the radiography of temporomandibular joint

Objective To compare the computed orthopantomography(COPT)with Shuller radiography(SR),film orthopantomography(FOPT)and other traditional radiographic techniques in the radiography of temporomandibular joint(TMJ).Methods Ninty-eight cases were randomly divided into 3 groups,and the open and close positions of TMJs of both sides were examined with SR,FOPT,and COPT, respectively.The satisfactory rates of the X-ray pictures were statistically analyzed with Pearson chi-square in SPSS10.0,and the satisfactory rates were analyzed with q test between the groups.Results One hundred and forty-four of the open and close positions of 144 TMJ pictures of the COPT group,128 of 128 of the FOPT group,and 6 of 120 of the SR group were satisfactory in the mandible ramus of the TMJ,with satisfactory rate being 100%,100%,and 5%,respectively(P0.01).Coronoid process was satisfactorily shown in 144,128,and 12 pictures,with satisfactory rate being 100%,100%,and 10% respectively in the 3 groups(P0.01).Incisure was satisfactorily shown in 144,128,and 66 pictures respectively,with satisfactory rate being 100%,100%,and 55%(P0.01).The joint space was satisfactorily shown in 96, 89,and 120 pictures respectively,with satisfactory rate being 75%,62%,and 100%(P0.05).The condylar process and articular tubercle were satisfactorily shown in 144,128 and 120 pictures respectively, with satisfactory rate being 100% in all the 3 groups.The satisfactory rates of the mandible ramus,coronoid process,incisure,and joint space were compared between the groups.(average P0.01),respectively between FOPT and COPT groups.The difference was not statistically significant.The exposure was as follows:COPT,99—113 mAs;FOPT,210—225 mAs;and SR,48—75 mAs.Therefore,COPT and FOPT were superior to SR in the pictures of the mandible ramus,coronoid process,and incisure,but inferior in the joint space pictures.The satisfactory rates of the condylar process and articular tubercle were same in the 3 groups.The exposure of the FOPT group was greater than that of the COPT and SR groups.Conclusion COPT is superior to SR and FOPT in TMJ radiography,and should be applied widely in the clinic.