Three-dimensional Bone Mass Of Maxillary Tuberosity And Its Relationship With Third Molars By CBCT

Objective: To analyze the regulation of the maxillary tuberosity(MT)in three-dimension(width,length,and height),the influence of the third molar,their correlations with age and sex,and the main factor of the change.Methods: From 2017 to 2018,63 adult patients(33 males and 30 females)were selected from the Department of Stomatology,904 Hospital of the PLA,with an average age of 26.4 years and an age range of 20-40 years.The CBCT images of 63 patients with congenital unilateral missing of the maxillary third molar were collected and divided into group A and group B.Using Invivo5 software to reconstruct the image and measure the bone mass of the distal maxillary second molars.Group Ameasured 567 variables in length,width and height,and group B measured 378 variables in length and width.Results1.In group A,the height and width of maxillary tuberosity showed a decreasing trend away from the maxillary second molar,the largest length at 6mm below the CEJ(cemento-enamel junction);2.2.The MT dimensions showed correlations with age,whereby older patients presented with greater length,but reduced height.The width were no statisticallysignificant.(p>0.05).3.Compared with group A,group B increased in the length and width of the bone mass,and the difference were statistically significant(p<0.05).4.There was no significant difference for gender in groups A and B?5.The main factor analysis showed that the width accounted for 47.3%;the height accounted for 25.3%,and the length accounted for 10.9%.Width,length and height account for 83.5% of bone mass changes together.Conclusion Cone beam CT accurately analyze the three-dimensional changes of the maxillary tuberosity,and the influence of the third molar on the MT.The dimensions of the MT vary according to patient age.The main factors affecting the bone mass of the MT are also showing.It has a very important clinical significance in guiding the formulation of orthodontic treatment plan,and improving the safety the MT implantation.