Study On The Relationship Between Maxillary Molar Depression And Maxillary Sinus By CBCT

ObjectiveTo provide a reference for clinical orthodontic treatment,studing on the degree of reduction of maxillary first molar in the different relationship between maxillary first molar and maxillary sinus,the degree of root resorption,and the changes of maxillary by using conical beam computed tomography(CBCT).MethodsPre-treatment CBCT films of 60 adult(collected in January 2017-January 2018 in the first affiliated hospital of zhengzhou university orthodontics cases)who's maxillary first molar should be intruded were divided into 3 groups according to their different relationship with maxillary sinus,including group A(maxillary first molar root are all from the maxillary sinus,namely d > 0 mm),group B(maxillary first molar root is close to the maxillary sinus,and the most d = 0 mm),group C(maxillary first molars had at least one root into the maxillary sinus,namely d < 0 mm),Every group includes 20 cases.Three-dimensional reconstruction was made for CBCT by Invivo 5.2 image processing software.Measuring on the amount of intrusion in CBCT images,analysis of root absorption,maxillary sinus recongstruction.The data was analyzed with SPSS 20.0 software package.Results1? Relationship between the root of the maxillary first molar and the maxillary sinus: the ratio of palatal root,proximal and distal buccal root to the maxillary sinus floor(d<0mm)was 11.11%,6.11%,4.44%;the ratio of palatal root,proximal and distal buccal root to the maxillary sinus floor(d=0mm)was 9.44%,10.56%,8.89%;the ratio of palatal root,proximal and distal buccal root far away from the maxillary sinus floor(d>0mm)was 12.22%,17.22%,20.00% respectivaly.2?Deression: after orthodontic treatment in group A,the depression of mesiobuccal root was(2.71±0.57)mm,distal buccal root was(2.44±0.38)mm,and palatal root was(2.33±0.52)mm;after orthodontic treatment in group B,the depression of mesiobuccal root was(2.67±0.54)mm,distal buccal root was(2.67±0.52)mm,and palatal root was(2.48±0.51)mm;after orthodontic treatment in group C,the depression of mesiobuccal root was(1.92±0.59)mm,distal buccal root was(1.9±0.65)mm,and palatal root was(1.84±0.57)mm.There was no statistical significance between group A and group B,while statistical significance between group C and group A,B.There was no statistical significance between the three root depression levels in group A,group B,group C.3?Root absorption: after orthodontic treatment in group A,the absorption of mesiobuccal roots,distal buccal roots and palatal roots was concentreted in the absence of obvious absorption and mild root absorption,and only 10% of palatal roots showed moderate root absorption.In group B,10% of mesiobuccal roots had moderate to severe absorption,20% of distal buccal roots had moderate to severe absorption,25% of palatal roots had moderate to severe absorption,and 5% of palatal roots had ectremely severe absorption.In group C,25% mesiobuccal roots had moderate to severe absorption,5% mesiobuccal roots had ectremely severe absorption,60% distal buccal roots had moderate to severe absorption,5% of distal buccal roots had ectremely severe absorption,70% palatal roots had moderate to severe absorption,5% palatal roots had ectremely severe absorption.4?Changes of maxillary sinus: there were no changes of maxillary sinus in group A,3 casas of maxillary sinus subcortical bone discontinuity were added in group B after treatment,2 cases of mucosal hyperplasia were added,and 4 cases of mucosal hyperplasia were added after depression in group C.Conclusion1?Palatal root of maxillary first molar is most closely related to maxillary sinus.2?No matter how the maxillary first molar is in contact with maxillary sinus,the depression process can guarantee the vertical depression.Among them,when the maxillary first molar has a root protruding into the maxillary sinus,the reduction will be reduced.3?The closer the relationgship between the maxillary first molar and maxillary sinus,the more the root absorption after orthodontic treatment,and the most obvious root absorption is the palatal root.4?The closer the relationgship between the maxillary first molar and maxillary sinus,the more likely the cortical and mucosa of maxillary sinus are to change after depression treatment.