| Objective:The MRI examination was taken in patients with ID(Internal derangement)and control group.Comparing the two groups to analysis the changes in thickness of articular discs of the TMD and variations law in thickness of the articular discs in different degree of mandibular dyskinesis.Increasing the clinician’s clinical knowledge of ID and guiding for clinical diagnosis and treatment.Methods:1.From the Department of Stomatology,the second hospital of Shanxi medical University,15 ID patients were selected as subjects(the average age was 30.4±8.64years)from patients with TMD symptoms such as joint pain,snapping,and abnormal mouth opening.Ten volunteers(mean age 30.6±5.66 years)with no temporomandibular joint symptoms were selected as the control group.Detailed medical history,temporomandibular joint specialist examination,and bilateral MRI examinations were performed on patients which meeting the inclusion criteria and controls.An oral medical examination chart was used to record the medical history and physical examination results.2.To explore the changes in the thickness of the anterior band,intermediate zone,posterior band and bilaminar region of the articular discs in different course of ID and different levels of mandibular dyskinesis,we group the ID group as follows:According to which side the ID occurred,the ID group divided into the healthy group and the affected group;according to the progress of ID it was divided into ADDR group and ADDWR group;As for the abnormal mandibular movement,we grouped the ID group with limitedmouth opening and opening type abnormalities,about the limited mouth opening,we group the ID group with no mouth limitation,mild mouth limitation,and moderate mouth limitation.In the case of open type abnormality,the IDs groups as normal opening type group,deviation group,and locking group.3.In the sagittal positions of the control group and the ID group,the thickness of the articular discs in the anterior band,intermediate zone,posterior band and bilaminar region of the bilateral articular discs were measured.The differences in the thickness of the various parts of the articular disc between the control group and the ID group were compared and analyzed,to know the variation and changing law of the thickness of the articular disc in different course of disease and degree of abnormal mandibular movement,guiding for clinical diagnosis and treatment.Results:1.According to MRI measurements and comparison of the disc thickness in the control group,the difference are there in the posterior band and bilaminar region areas about the thickness of bilateral articular discs in the control group(P<0.05),the differences were statistically significant.2.Comparing between the control groups and the healthy,affected group of ID,the thickness of the anterior band,intermediate zone,posterior band and bilaminar region of the healthy and affected group were thickened,and the thickening of healthy side in the intermediate zone and bilaminar region had statistically difference(P<0.05),as for the affected side,there were statistically differences in the thickness of intermediate zone(P<0.05).Comparing the healthy side and the affected side,it was found that the thickening of the intermediate zone in the affected side had statistical significance(P<0.05).3.Comparing the ADDR group,the ADDWR group and the control group,we found that the ADDR group and the ADDWR group had thickening in the anterior band,intermediate zone,posterior band and bilaminar region,the ADDR group were thickened in the anterior band,intermediate zone,posterior band and bilaminar region,and the differences have statistically difference(P<0.05);in the ADDWR group,there was a statistically significant difference in the intermediate zone(P<0.05).Comparing the thickness of the ADDWR and ADDR groups,intermediate zone got thickened,and was found has statistically difference in the ADDWR group(P<0.05),while ADDR has a statistically significant thickened in the posterior and double plate areas(P<0.05).4.In the mouth opening limitation group,after the multiple comparisons between the groups,the thickness of anterior area of the articular disk shows that moderate mouth limitation group> mild mouth limitation group> no mouth limitation group> control group,and there were no statistically difference among the three groups with light and moderate mouth opening limitation and no mouth opening limitation(P>0.05),but the statistical differences between the three groups and the control group was found(P<0.05).The changes in the thickness of the posterior region of the articular disk were slight opening limitation group> no opening limitation group> control group and moderate opening limitation group has no statistically significant difference(P>0.05).There are statistically significant differences in the thickness of the bilaminar region between the moderate mouth opening limitation group and the other groups but not in others.(P<0.05)In the open-type abnormal group,the thickness of the anterior region between the groups presented as the lock group> opening deviation group> opening normal group>control group,statistical results showed that there was no statistical difference between the three of ID groups(P>0.05),and there are statistical differences between the ID groups and the control group(P<0.05).The changes in the thickness of the posterior region of the articular disc were as follows: opening deviation group> opening normal group> control group> locking group,and the thickness of the posterior band and bilaminar region has no significantly different between the groups(P>0.05).Conclusions:1.The change of the thickness of the articular disc was more obvious in the intermediate zone,its thickness continued to thicken with the development of the disease,and then the reconstruction of the posterior band and bilaminar regions was active.With the progression of the disease,it was thickened in the early but the thickness decreased with the progression of the disease.2.In patients with abnormal jaw movements,the change in the thickness of the anterior region which is is mainly in the intermediate zone,was thickened on the MRI images.3.MRI can accurately reflect the thickness changes of the anterior band,intermedi-ate zone,posterior band and bilaminar region regions with different degrees of progres-sion of ID and different degrees of movement disorders,guiding for the clinical diagnosis and treatment of ID. |
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