Evaluation Of Pathologic Findings In The Area Of The Maxillary Sinus And Its Change In Sinus Dimension Following Dental Implant Placement In The Posterior Maxilla: A Retrospective Cone-beam Computed Tomographic Study

Objective: Maxillary sinus is an important anatomical structure that the operatorshould consider during the dental implant placement in the maxillary posterior sitewith alveolar bone resorption, but there is always some pathologic findings in the areaof the maxillary sinus. The aim of this study was to assess the effect of dentalimplants on pathologic findings in the maxillary sinus by using cone-beamcomputerized tomography (CBCT) and identify the associated factors.Material and methods:In this cohort study, data from routine patients attendingthe West China Hospital of Stomatology,Sichuan University or The affiliatedStomatological Hospital of Nanchang University, and referred for dental implantplacement in the posterior maxillary at the Department of implantology during theperiod Jan,1st,2012–Mar,31st,2013were retrospectively analyzed.Results:1861patients were scheduled for implant placement in the posteriormaxillary. The consecutive preoperative CBCT scans were retrospectively inspectedfor pathologic findings in the maxillary sinus. Abnormalities were diagnosed in57.39%of cases(1068findings). Flat mucosal thickening was the most prevalentabnormality (763findings,40.99%), followed by polypoidal mucosal thickening(168findings,9.03%),opacification with liquid accumulation(72findings,3.87%)andcalcification(65findings,3.49%).The final sample, after controlling for inclusion andexclusion criteria, included93sinuses corresponding to93patients, and93pairs ofcoincident preoperative and postoperative CT scans. The mean age of the patientswas53.51±10.75years, the youngest patient was19years old, and the oldest patientwas69years old at the time of the investigation.57patients (61.29%) were male and36(38.71%) were female. The mean time difference between the preoperative and thepostoperative CT scans was7.05±2.18months. Different types of abnormal findingswere recorded: flat mucosal thickening(66findings), polypoid mucosalthickening(15findings),opacification with liquid accumulation(10findings)andcalcification(2findings). Implant placement was divided into four approachs: implantsnot penetrating the sinus membrane（23findings,24.73%）,implants penetrating the sinus membrane （7findings,7.53%）, implants with transalveolar technique(60findings,64.52%), implants with one-stage lateral technique(1findings,1.08%),implants with two-stage lateral technique(2findings,2.15%).Maxillary sinus bleedingoccurred after implant surgery in9patients.With the use of additional antibiotics for5days, sinus bleeding disappeared in8patients during the follow-up.A total of186preoperative and postoperative CBCT were analyzed with regard to the height of thesinus abnormality.A linear regression model was used to explain the differencebetween the mean preoperative and postoperative pathologic space. The preoperativemean height of the abnormality was5.93mm and the postoperative height was4.72mm.Significant decreace of dimension in sinus abnormality was shown betweenpre and postoperative CT scans (P <0.005). The multivariate analysis performed toidentify variables associated with the postoperative sinus abnormality shows thatfemale significantly reduces to a smaller dimension (P<0.05). Different ways ofplacement is another important factor.The mean height of the alveolar ridge was5.99mm before the operation and8.50mm during the follow-up.The height significantlyincreased after dental implant placement (P <0.001).Conclusions:Our findings suggest that:(1)Dental implant placement oraugmentation procedure has impact on the l sinus pathologic findings; significantdecreace of dimension in sinus abnormality was shown. The mean postoperativedimension may be affected by gender and the different ways of placement.(2)CBCTis gaining increasing popularity in implant dentistry especially for evaluating bothresidual alveolar and sinus and being the guideline for three-dimensional treatmentplanning.(3)A dental implant procedure within reasonable indications and clinicalskills seems to be safe and predictable in the presence of a pathologic finding in themaxillary sinus in asymptomatic patients.