| Background:Inadequate alveolar bone in the maxilla is a common limitation for inserting dental implants in the posterior maxilla.Several sinus augmentation techniques,including by lateral wall or by alveolar ridge,designed to allow insertion of simultaneous or delayed dental implants have been based on the insertion of different materials between the host bone and the sinus membrane in order to obtain bone augmentation.The osteoconductive activity of various bone substitutes has been tested by the quality and quantity of newly formed bone in the augmented area,it is the concensus that the mechanism of new bone formation with the graft material in the alveolar bone area is the principle of guide bone regeneraiton,however,without consensus to the maxillary sinus cavity.In addition,recent clinical studies have shown that bone augmentation can be achieved by simply elevating the maxillary Schneiderian sinus membrane,without any graft materials.Likewise,a few case reports have described enhanced bone formation following cyst and tooth removal from the maxillary sinus,again,in the absence of any implanted osteoconductive material.Taken together,these studies suggest an inherent,latent osteogenic activity of the Schneiderian membrane.Whether maxillary sinus membrane contains osteogenesis potential after maxillary sinus lifting and the exact mechanism of bone formation need to be further researched.Objectives(1)To explore whether maxillary sinus membrane contains osteogenesis potential,whether the charateristics are the same as the ones of the periosteum of the maxillofacial bone.(2)To evaluate the osteogenesis mechanism in the space of maxillary sinus lifting.Methods and materials(1)To collect the 3-dimension radiographic information of 10 cynomolgus monkeys by CBCT scanning and learn the applied anatomy of maxillary sinus of the experimental species.(2)To design and fabricate the new barrier device for space maintaining after sinus membrane lifting according the CBCT data,built the pre-model on animal skull and obtain the stability of the device(3)6 animals were divided into 2 groups at random,6 weeks and 16 weeks respectively and 3 ones for every group,four barrier devices from 4 types with different designs(secluded,0.5mm,0.75mm or 1.0mm holes)were screwed in every side of mandible,one of each design respectively,evaluate the new bone formation in different areas from the radiographic and histological data.(4)6 animals were divided into 2 groups at random,6 weeks and 16 weeks respectively and 3 ones for every group,two types(with 0.5mm or 1.0mm holes)barrier devices were screwed in maxillary sinus floor for every animal,every side sinus with one device of one type,two types for left or right at random,the sinus membrane were maintained in lifting condition,evaluate the new bone formation in different areas from the radiographic and histological data.Results:(1)The CBCT data showed the animal sinus can be used for sinus lifting procedures and the bone window was be measured(2)The animal model was constructed successfully and the new titanium barrier device was meet to this surgery(3)The result showed new bone formation in different area by mandibular periosteum lifting and maintaining by barrier device,the more the hole size of the device the more bone formation in the space of devices,it is suggested the mandibular periosteum contains the osteogenic potential(4)The result showed new bone formation in various area by sinus membrane lifting and maintaining by barrier device,the more the hole size of the device the more bone formation in the space of devices,new bone formation underlying sinus membrane with sufficient blood supply.Conclusions:(1)The sinus membrane contains osteogenic capability in the environment of guide bone regeneration,the charateristics are similar to the ones of the periosteum of the maxillofacial bone.(2)The osteogenic mechanism of sinus lifting seems to be like the principle of guide bone regeneration. |
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