CBCT Study On The Area From The Apices Of Maxillary Posterior Teeth To Maxillary Sinus Floor And Mucous Cyst Of Maxillary Sinus

Objective: Maxillary sinus floor is closely related to maxillary posteriorteeth,maxillary posterior teeth xeodontia and root canal treatment and dentalimplantation occurs oroantral communications or maxillary sinus infectionrisk. In addition, maxillary sinus lift is bone augmentation technology is veryimportant in treatment of implant in maxillary posterior region, mucousmembrane of maxillary sinus of the situation direct effects on maxillary sinusaugmentation.To observe and to measure vertical distance between eachmaxillary molar root apex and maxillary sinus floor by cone beam CT, so as todetermine the root that is the most closely related to maxillary sinus floor; toobserve and to determine the occurrence of mucous cyst of maxillary sinusand its predilection site, providing valuable references for the clinicaltreatment and dental implantation.Methods: Cone beam CT was performed on posterior region of themaxilla in100patients from the Stomatological Hospital of Hebei MedicalUniversity from January1,2012to June1,2013, among which there were50males and50females. Inclusion criteria:①Patients were aged18to45years,②Maxillary premolar and molar teeth(excluding the third molar) no missingand no deformity,③They had no history of orthodontic and orthognathictreatment,④They have no congenital deformity of maxilla,⑤They were ingeneral good health.The patient was asked to sit relaxed, with facial midlinevertical with the ground and Frankfort plane parallel to the ground, and thenhis/her head was fixed.Cone beam CT scanner (KaVo3D eXam, USA) wasemployed to obtain image data, which were then observed in cross section,coronal and sagittal planes, respectively, under the interface of softwareInvivo5, in order to determine all maxillary posterior teeth roots that were theclosest to maxillary sinus floor, and to measure vertical distance between the teeth root apex and bony edge of maxillary sinus floor.They were classifiedaccording to the relationship between the root measured to be the closest tomaxillary sinus floor and the corresponding position of maxillary sinus floor.In classification A roots, the root apex was lower than maxillary sinus floor; inclassification B roots, root apex and maxillary sinus floor were at the samelevel, and in classification C roots, root apex was higher than maxillary sinusfloor.Patients with mucous cyst of maxillary sinus were observed andanalyzed by means of the cone beam CT, so as to calculate the incidence ofmaxillary sinus cyst and its predilection site on the sinus wall.Results:1There were no statistical differences between men and women,left andright.In classification A roots,the average distances from small to largebetween the maxillary posterior teeth roots and the maxillary sinus floor wereas follows: the first molar palatal root,（1.85±0.68）mm; the second molarmesiobuccal root,（2.62±0.74）mm；the second molar buccal fused root,（3.16±0.62）mm；the second molar distobuccal root,（3.88±0.53）mm；thefirst molar distobuccal root（,3.96±0.68）mm；the first molar mesiobuccal root,（4.33±0.65）mm；the second molar palatal root（,4.50±0.97）mm; the secondpremolar,（5.83±0.86）mm；the first premolar palatine root,（7.86±2.41）mm；the first premolar single-root,（12.31±3.33）mm；the first premolarbuccal root,（13.26±4.04）mm. In classification B roots, the quantity frommore to less were as follows: the first molar distobuccal root92, the firstmolar mesiobuccal root76, the first molar palatal root67, the second molarpalatal root59, the second premolar51, the second molar mesiobuccal root50,the second molar distobuccal root46, the second molar buccal fused root30,the first premolar single-root5, the first premolar palatine root4, the firstpremolar buccal root1. In classification C roots, the average distances fromlarge to small between the maxillary posterior teeth roots and the maxillarysinus floor were as follows: the first molar palatal root,（-2.50±0.89）mm; thesecond molar mesiobuccal root,（-2.33±0.65）mm；the second molar palatalroot,（-2.31±0.76）mm; the second molar buccal fused root,（-2.29±0.71） mm；the first molar distobuccal root,（-2.28±0.84）mm；the first molarmesiobuccal root,（-2.25±0.62）mm；the second molar distobuccal root,（-1.91±0.53）mm；the second premolar,（-1.85±0.61）mm.2In this study, a total of197root tip into the maxillary sinus and thenumber of the maxillary posterior teeth from more to less as follows: the firstmolar palatal root60, the second molar mesiobuccal root34, the first molarmesiobuccal root24, the second molar palatal root20, the first molardistobuccal root18, the second molar buccal fused root15, the second molardistobuccal root14, the second premolar12.3Of the100patients,17cases had unilateral mucous cyst of maxillarysinus, male13cases, female4cases and2cases had bilateral mucous cyst ofmaxillary sinus, male1cases, female1cases, therefore, the occurrence ofmucous cyst of maxillary sinus was19%. Occurrence of mucous cyst ofmaxillary sinus in maxillary sinus floor in12cases,accounting for all ofmaxillary sinus cyst location57.14%;5cases of mucous cyst of maxillarysinus in the medial wall of the maxillary sinus, maxillary sinus cysts of allparts of the23.81%; occurrence of mucous cyst of maxillary sinus inmaxillary sinus anterior wall and lateral wall of the latter were2cases,accounting for9.52%; occurrence of mucous cyst of maxillary sinus inmaxillary sinus sphenoidalis upper in0cases.Conclusion:1CBCT is more reliable in distinguishing the distance between maxillaryposterior teeth root and the maxillary sinus floor.2Maxillary posterior teeth is closely related to maxillary sinus floor, andis most closely related to the first molar palatal root.3CBCT detection of maxillary sinus mucosa cyst occurrence has certainguiding significance.