A Study Of Anatomical Structures Of Maxillary Sinus Based On Cone-beam CT

After loss of maxillary posterior teeth, pneumatization of the maxillary sinus and the absorption of alveolar bone often result in alveolar ridge insufficient for dental implant. The maxillary lateral wall window technique and sinus floor augmentation technique were used to increase alveolar bone height.Maxillary sinus septa, posterior superior alveolar artery of maxillary sinus lateral wall and maxillary sinus lateral wall thickness are different in individual, which will cause a certain impact on the operation. Therefore it is very important to learn the anatomical structures of maxillary sinus associated with dental implant before surgery. Since the application of CBCT in oral field, its unique advantages bring a lot of convenience to oral clinicians and patients. This research study three-dimensional structures of maxillary sinus related with planting operation in the sagittal, coronal and transverse plane by useing CBCT, so as to provide information for clinical operation and avoid the occurrence of operation complications.Part one A study of maxillary sinus septaPurpose:To examine the prevalence,location and height of sinus septa by useing cone-beam computed tomography.Method:CBCT image data were selected from three hundred patients. We examine the prevalence, location and height of sinus septa. Data was analysed by SPSS 17.0 satatistical software.Results:1. The proportion of the occurrence of maxillary sinus septa in 300 subjects was 22.66% (68/300) and 13.33% in 600 maxillary sinuses(80/600). The prevalence of septa was not significantly related to gender and the presence or absence of teeth.2. The maxillary sinus septa were mainly in middle region of maxillary sinus,in which the first and second molar located. It’s mean height in left maxillary sinus was 7.59±5.66mm, in right for 6.70±4.23mm.Conclusion:Maxillary sinus septa mainly located in maxillary first and second molar area.Part two A Study of the posterior superior alveolar arteryPurpose:To examine the prevalence of PSAA and measure its diameter and the distance from bone canal to the alveolar ridge crest.Method:CBCT images were randomly selected from three hundered patients. We measure diameter of PSAA and the distance from PSAA to the alveolar ridge crest at different teeth. We also measured residual alveolar bone height in missing teeth group. Date was analyzed by using SPSS 17.0 software.Results:1. PSAA (bony canal) was identified in 44% of the cases (132 of 300 subjects), was all intraosseous or below the schneiderian membrane.2. The group without missing maxillary posterior teeth:The mean diameter of the bone canal was 0.91±0.22mm,0.91±0.22mm,0.99±0.26mm at P2, M1, M2. There were no significant differences on the mean diameter of the bony canal both sides of maxillary sinus at P2, M1, M2. There was statistically significant difference between women and men at P2, M1, M2.There was statistically significant difference at P2 among age groups. The group with missing maxillary posterior teeth:The mean diameter of the canal was measured 0.88±0.25mm at M1.No statistically differences were found with regard to left and right sides or genders for bony canal diameter at M1.3. The group without missing maxillary posterior teeth:The mean distances between the lower border of the PSAA (bony canal) and the alveolar crest were 20.94±3.47mm, 17.35±2.98mm,17.81±3.20mm at P2, M1, M2. There was no statistically significant difference between the sides of right and left, at P2, M1, M2. There was statistically significant difference between women and men at P2, M1, M2.There was statistically significant difference among age groups at M1. Missing maxillary posterior teeth group, the mean distances between the lower border of the PSAA (bony canal) and the residual alveolar bone height was 14.48±3.94mm at M1. No statistically differences were found with regard to left and right sides or gender for distances. Residual alveolar bone height was 8.12±3.69mm at M1. There was significant correlation between the distances from the lower border of the PSAA (bony canal) to the residual alveolar bone and the residual alveolar bone height with Pearson correlation.Conclusion:The group without missing maxillary posterior teeth (P2, Ml, M2) the mean distance from bony canal to the alveolar ridge crest was changed at different teeth. The shortest distance to the alveolar ridge crest was 17.35±2.98mm at M1. Missing maxillary posterior teeth group:the mean distance from bony canal to the alveolar ridge crest was 14.48±3.94mm at M1.Part three A study of maxillary sinus lateral wall thicknessPURPOSE:To evaluate the lateral wall thickness of the maxillary sinus in normalpopulation by useing CBCT. Methods:Two hundred sides of maxillary sinus in one hundred adult patients were randomly collected. We measured the lateral wall thickness above one centimeter from the sinus floor at different teeth by useing CBCT. All datum were analysed by SPSS 17.0 satatistical software.Results:1. The mean thickness of maxillary sinus lateral wall at the P2, M1, M2 was 1.49±0.55mm,2.05±1.01mm,1.64±0.61mm, respectiveiy. The thickness of maxillary sinus lateral wall was at the first molar area.2. There was no statistically significant difference between left and right side at P2, M1, M2. There was statistically significant difference between women and men at P2, M1. There was no statistically significant difference between women and men at M2 There was no statistically significant difference at P2, M1, M2 among age group.Conclusion:The mean thickness of lateral wall was changed at P2, M1, M2. The thickest of maxillary sinus lateral wall was at the first molar area.