Relationship Of The Posterior Teeth With The Mandibular Canal And Maxillary Sinus And It's Three-dimensional Reconstruction

The dental implant operation is a kind of new technique and method to repair the dental defect with well function and appearance, however during the procedure of the dental implant operation, especially in the alveolar crest atrophy of the old patient, it often causes a series of the complication. For example, the maxillary infection and fistula due to the astray of the maxillary dental root to pierce into the maxillary sinus, and the numb or anesthesia of the mandible due to the inferior alveolar nerve is injured by the mandibular dental root, the main reason is that the dentists do not completely understand the anatomic characteristics of the position and course of the mandibular canal and the maxillary sinus, and the position relation of the mandibular canal and the maxillary sinus with the dental root of posterior teeth (premolar and molar). Therefore, all above mentioned constricts the application and development of the dental implant operation. The purpose of this study is to provide practical anatomic data for the dental implant operation of oral surgery and oral anatomy by studying the applied anatomy of the maxillofacial specimen, CT 3D reconstruction of living body, the reconstruction and visualization of Digital Virtual Human data by the Amira software. Part.l The applied anatomy about the position relation of the mandibular canal, maxillary sinus with the posterior teethObjective:To provide applied anatomic data for the dental implant operation of oral surgery by observation the position and course of the mandibular canal, relationship of the inferior alveolar nerve with the inferior alveolar vessels, anatomic characteristics of the maxillary sinus, measurement the alveolar socket depth of the posterior teeth, the distance from the apex of dental root (the base of alveolar socket) to the mandibular canal and maxillary sinus respectively in specimens.Methods:The position and course of the mandibular canal, the shape of the inferior wall of maxillary sinus were observed, and measured the alveolar socket depth (the base of alveolar socket to the highest point of alveolar crest) of the posterior teeth, and the distance from the apex of dental root to the superior wall of mandibular canal and the inferior wall of maxillary sinus respectively in specimens of the 20 adults (40 sides). The measured data were carried on the calculations of the mean and standard deviation by the SPSS 13.0 statistical software, and the measured data of both sides were carried on the paired T-test. The relationship of the inferior alveolar nerve with the inferior alveolar vessels was observed, the shape of the inferior wall mucosa of maxillary sinus in fresh specimens of 10 adults (20 sides).Results:(1) The inlet of mandibular canal was the mandibular foramen,65.0% of it was inverted triangle, and related to the position of the mandibular lingula. The outlet of mandibular canal was the mental foramen, it was ellipse, and 50.0%of it was situated under the mandibular first premolar. The mandibular canal was traveling through the bottom of the mandibular alveolar socket, it was ellipse in section of the mandibular body, and the distance from the mandibular canal to the lateral plate of mandible was thick than it to the medial plate, the distance from the mandibular canal to the alveolar crest was longer than it to the inferior edge of mandibular body. The inferior alveolar nerve and vessels were enclosed by the connective tissue to form a neurovascular bundle in the mandibular canal, and the inferior alveolar vessels were laid above the inferior alveolar nerve. (2) The alveolar socket depth (12.70±1.15 mm) of the mandibular second premolar was the deepest among that of the posterior mandibular teeth, and the alveolar socket depth (9.84±1.20 mm) of distal root of the left mandibular third molar was the shallowest. From the deeper to the shallower, it was the mandibular second premolar, mandibular first premolar, mandibular second molar, mandibular first molar and mandibular third molar in turn. The distance (2.92±0.75 mm) from the apex of distal root of the right mandibular second molar was the shortest among that of the posterior mandibular teeth, and the distance (8.29±0.88 mm) from the dental root of right mandibular first premolar was the longest. From the nearer to the farther, it was the mandibular second molar, mandibular first molar, mandibular third molar, mandibular second premolar and mandibular first premolar in turn, and the distance from the mesial root of mandibular molar to the superior wall of mandibular canal was longer than that of the corresponding distal root. (3) The maxillary sinus was a triangular or quadrilateral cone-shaped space,70.0%of it was symmetry. The inferior wall of maxillary sinus was usually irregular, the processes of bony and mucosal septum were often appeared on it, which separated the maxillary sinus into numerous chambers usually lying between the maxillary second premolar and maxillary first molar, but the bony septum did not appear under the 60.0%mucosal septum. (4) The alveolar socket depth (13.03±0.85 mm) of the right maxillary second premolar was the deepest among that of the posterior maxillary teeth (premolar and molar), the alveolar socket depth (6.91±1.17 mm) of distobuccal root of the maxillary third molar was the shallowest. From the deeper to the shallower, it was the maxillary second premolar, maxillary first premolar, maxillary first molar, maxillary second molar and maxillary third molar in turn. The distance (1.80±0.57 mm) from the apex of mesiobuccal root of the left maxillary first molar to the inferior wall of maxillary sinus was the shortest among that of the posterior maxillary teeth, and the distance (9.98±1.15 mm) from the lingual root of the right maxillary first premolar was the longest. From the nearer to the farther, it was the maxillary first molar, maxillary second molar, maxillary third molar, maxillary second premolar and maxillary first premolar in turn. The distance from the mesiobuccal root of maxillary molar to the inferior wall of maxillary sinus was shorter than that of the corresponding distobuccal root and lingual root, from the nearer to the farther, it was the mesiobuccal root, lingual root and distobuccal root in turn.Conclusion:It is important to select appropriate length of the dental implantation, and avoid the dental implantation injuring the inferior alveolar nerve and pierce into the maxillary sinus by studying the course of the mandibular canal, inferior wall of the maxillary sinus, alveolar socket depth of the posterior teeth and the distance from the apex of dental root to the superior wall of mandibular canal and the inferior wall of maxillary sinus respectively.Part.2 CT three-dimensional reconstruction about the position relation of the mandibular canal, maxillary sinus with the posterior teethObjective:To provide imaging data for the dental implant operation of oral surgery by observation the position and course of the mandibular canal, the anatomic characteristics of the maxillary sinus, and measurement the distance from the apex of dental root to the superior wall of mandibular canal and the inferior wall of maxillary sinus respectively in CT and 3D reconstruction images.Methods:20 adult volunteers were scanned in series by spiral CT based on the orbitomeatal line (OML), which were managed by the surface shaded display (SSD), the curve-planar reconstruction (CPR) and the multi-planar reconstruction (MPR) under the ADW 4.2 reconstruction software of CT 3D reconstruction workstation. Then, the coronal and sagittal MPR reconstruction images of the position relation of the posterior maxillary teeth (premolar and molar) with the maxillary sinus, the CPR reconstruction images of the mandibular canal, maxillary sinus, maxillary dental root, mandibular dental root, and the SSD 3D reconstruction images of the maxilla, mandible, maxillary teeth, mandibular teeth were obtained respectively. At last, the distance from the dental root of posterior mandibular teeth to the superior wall of mandibular canal, and from the dental root of posterior maxillary teeth to the inferior wall of maxillary sinus were measured respectively by the software of the CT 3D reconstruction workstation. The measured data were carried on the calculations of the mean and standard deviation by the SPSS 13.0 statistical software, and the measured data of both sides were carried on the paired T-test.Results:(1) In the images of the SSD 3D reconstruction, the inlet and outlet of the mandibular canal, the position and shape of the mandibular foramen and mental foramen were clearly display. In the images of the CPR reconstruction, the mandibular canal was composed of a thin compact bone, and extended to the midline and became thinner, and continued to be the mental foramen. (2) In the images of the CPR reconstruction through the mandibular canal, the distance (2.93±0.61 mm) from the apex of distal root of the mandibular second molar to the superior wall of mandibular canal was the shortest among that of the posterior mandibular teeth, and the distance (8.44±1.05 mm) from the dental root of right mandibular first premolar was the longest. From the nearer to the farther, it was the mandibular second molar, mandibular first molar, mandibular third molar, mandibular second premolar and mandibular first premolar in turn, and the distance from the mesial root of mandibular teeth to the superior wall of mandibular canal was longer than that of the corresponding distal root. (3) 80.0% of the maxillary sinus was pyramid and seated within the maxillary body, the inferior wall of 37.5% maxillary sinus was protuberant to form bony septum, which separated the maxillary sinus into numerous chambers. (4) In the images of the MPR reconstruction, the distance (2.13±0.50 mm) from the apex of mesiobuccal root of the left maxillary first molar to the inferior wall of maxillary sinus was the shortest among that of the posterior maxillary teeth, and the distance (10.09±1.16 mm) from the lingual root of right maxillary first premolar was the longest. From the nearer to the farther, it was the maxillary first molar, maxillary second molar, maxillary third molar, maxillary second premolar and maxillary first premolar in turn. The distance from the mesiobuccal root of maxillary molar to the inferior wall of maxillary sinus was shorter than that of the corresponding distobuccal root and lingual root, from the nearer to the farther, it was the mesiobuccal root, lingual root and distobuccal root in turn.Conclusion:It is important to implant correct and suitable position, direction and number of the dental implantation by the spiral CT scanning together with the surface shaded display (SSD), the curve-planar reconstruction (CPR) and the multi-planar reconstruction (MPR) to get the 3D reconstruction images, which could clearly display the maxillary and mandibular alveolar processes, maxillary and mandibular teeth, and the position relation of the mandibular canal, maxillary sinus with the dental root of posterior teeth. Further more, the 3D reconstruction images could be rotated in any angle and cut section arbitrarily for observation and measurement.Part.3 The visualization of the mandible, mandibular teeth and mandibular canalObjective:To provide the operating platform of virtual surgery for the dental implant operation of oral surgery by establishment the 3D visual model of the mandible, mandibular teeth and mandibular canal, and observe the position and course of the mandibular canal, the position relation of the mandibular canal with the dental root of posterior mandibular teeth (premolar and molar) in the diaphanous mandible.Methods:The data set of the Digital Virtual Human were get from the data acquisition, suitable cadavers selected, intraarterial infusion, fixed and milled, etc. Then the imaging data from the condylar process of mandible to the inferior edge of mandibular body were selected, and closed curve outline of the bony cortex of mandible, the teeth, alveolar processes and mandibular canal were portrayed. And reconstructed the data set of the Digital Virtual Human and obtained the 3D wireframe model and physical model with the smooth surface management by the Amira 3D reconstruction software. At last, adoption different Alpha parameters, and made the 3D wireframe model present a diaphanous mandible, which could clearly display the position, course of the mandibular canal and the position relation of it with the dental root of posterior mandibular teeth.Results:(1) The fine 3D model of the mandible was reconstructed using the data set of the Digital Virtual Human by the Amira 3D reconstruction software, which could represent the real anatomy of the mandible and mandibular teeth in the three dimensional direction. For example, the three dimensional model could clearly display the whole or part at any angle, amplification or lessening of the whole or part model, free-cutting, rotation, copying and storage. (2) The diaphanous mandible could display the position, shape and course of the mandibular canal and the position relation of it with the dental root of posterior mandibular teeth, and the distance from the mandibular canal to the inferior edge of mandibular body, alveolar crest and the medial, lateral plates of the mandible respectively.Conclusion:It is individually and accurately to provide the morphology data of the dental implant operation of oral surgery, and provide the three dimensional operating platform of virtual surgery for oral surgery by establishment the 3D visual model of the mandible, which presented the virtual anatomy of the mandible, mandibular teeth and mandibular canal.