Cone-beam CT Analysis Of Normal Anatomical Structures In The Posterior Maxilla Area

With the continuous development of oral and maxillofacial surgery and dental implant technology, more and more type of surgery carried out and indications for surgery are constantly expanding. At the same time, a number of relevant surgical complications turned up, and gradually attracted the attention of the physicians. One of the main reasons for these complications is the understanding of the anatomy of the surgical field is not thorough enough, preoperative evaluation and design are not complete. Due to the presence of the maxillary sinus, the anatomic complexity of posterior maxilla area is greatly increased. The anterolateral wall of the maxillary sinus is the front side of the maxillary bone and the bottom turns into the maxillary alveolar. The complex structure and changeable morphology combined with close relationship with maxillary tooth root makes the posterior maxilla area became a more complex area in dental treatment, the incidence of treatment complications is also higher. Therefore, oral treatment in this area must have a good pre-operative assessment and precisely design as surgical guidance. The development and usage of cone-beam CT (CBCT) allow physician to observe the area of the surgical cases from three-dimensional to perform a better analysis and design, which help to improve the success rate of surgery and reduce surgical complications. In this study, the normal anatomy of the posterior maxilla were observed from CBCT images, measurement and analysis were proceeded in order to make the normal anatomy of the posterior maxilla area structures become more clear and acknowledged by physician.Part Ⅰ Cone-beam CT analysis of the relationship between the roots of maxillary posterior teeth and their adjacent anatomical structuresObjective:To measure and analyze the positional relationship of maxillary posterior tooth roots and their adjacent anatomical structures to provide references for clinical treatment.Methods:The cases met the inclusion criteria were chosen from CBCT database of Stomatology Hospital of Shandong University. GALAXIS software was used to observe the classification of the relationship between the posterior maxillary tooth roots and the maxillary sinus floor, and to count the incidence of various types. The vertical distance from the roots apical to the bottom of the maxillary sinus and the horizontal distance from root midpoint to the adjacent alveolar bone plate were measured and carried out statistical analysis.Results:The type that root apical and maxillary sinus was separated by bone plates had the highest incidence. The mesiobuccal root of maxillary second molar had the shortest vertical distance to the maxillary sinus (P<0.05); the palatal root of maxillary second premolar and second molar had the longest vertical distances to the sinus floor (P<0.05). The first molar mesiobuccal root was nearest to the buccal bone plate (P <0.05), the first molar palatal root was nearest to the palatal bone plate (P<0.05). Conclusion:Posterior maxillary tooth roots have a close relationship with the sinus floor and the alveolar bone plate which should be noted in the clinical treatment; CBCT can show the relationship of posterior maxillary tooth roots and their adjacent anatomical structures clearly, suitable for accurate diagnosis and design before treatment.Part Ⅱ Cone-beam CT analysis of the maxillary sinus anatomyObjective:To observe the normal anatomical structures of the maxillary sinus using CBCT and its supporting software. Understanding the normal anatomy of the maxillary sinus and provide reference for dental treatment.Methods:The 150 cases met the inclusion criteria were chosen from CBCT database of Stomatology Hospital of Shandong University. GALAXIS software was used to observe the classification of the bottom wall of the maxillary sinus, the condition of sinus septa and the lowest point of the maxillary sinus, the posterior superior alveolar canal and the lateral wall thickness, and carried out statistical analysis.Results:The incidence of flat, triangular, sub-ridge type of the maxillary sinus floor was 41.67%,30.67%,27.67%respectively. Sinus septa observed on the left, right, double side were 13.33%,7.33%,17.33%respectively. The mean distance from the lowest point of maxillary sinus bottom, exist mostly at the first molar region account for 46%, to the alveolar crest was 8.95 ± 3.57mm. The incidence of the front point of the maxillary alveolar canal was 95%, with an average diameter of 1.05 ± 0.36mm and 28.04 ± 2.44mm to the alveolar crest, while the rear point was observed probability of 93.33%, with an average diameter of 0.89 ± 0.29mm and 18.86 ± 2.78mm to the alveolar crest. The comparison between the diameter was statistically significant. Lateral wall thickness at the section of the lowest point of sinus floor was 2.30 ± 0.98mm,1.69 ± 0.76mm,1.52 ± 0.73mm respectively away from the sinus floor for 2mm,4mm,6mm and the difference was statistically significant.Conclusions:Sinus anatomy varies a lot. The use of CBCT can provide a better observation and analyze of the target structures and help to make an accurate design, reduce the incidence of complications.