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Modified Maxillary Sinus Floor Elevation Via A Mini-lateral Window With Simultaneous Placement Of Dental Implants:Clinical Trial And Early Osteogenesis Study In Vivo

Posted on:2019-05-24Degree:DoctorType:Dissertation
Country:ChinaCandidate:L Q ZhuFull Text:PDF
GTID:1314330548954817Subject:Of oral clinical medicine
Abstract/Summary:PDF Full Text Request
Objective:The purpose of this study was(1)to evaluate the clinical efficacy of modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implants;(2)to measure the relevant anatomical data of beagle dog maxillary sinus in CBCT image and to construct the animal model of modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implant;(3)taking the animal model of maxillary sinus floor elevation via a traditional-lateral window with simultaneous placement of dental implant as a contrast,to analyze and compare the early osteogenic effect in sinus of the animal model of modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implant.Methods:1.A retrospective study of 34 cases of modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implants was performed.There were 21 cases with mini-round-like window and 13cases with mini-slot window.The alveolar bone height and the bone height at the apical area of implants were measured and analyzed before operation,immediately post operation,6 months post operation,and 6 months post loading,12months post loading and 24 months post loading.At the same time,the intraoperative and postoperative ISQ values,complications,pain visual score and implant failure rate were observed and recorded,which were comprehensively evaluated the clinical effect of modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implants.2、12 beagle dogs were underwent CBCT scanning with general anesthesia and the three dimensional image was reconstructed.Some relative anatomical data was measured and recorded at the coronal section corresponding the cusp vertex of the fourth premolar(PM4)and the alveolar ridge apex of distal root of PM4.The data was including the width of maxillary sinus,the height of maxillary sinus,the palatal plate thickness,the distance between palatal alveolar ridge and the sinus floor,the thickness of the upper buccal bone plate of infraorbital nerve tube,the thickness of the middle buccal bone plate of infraorbital nerve tube,the thickness of the lower buccal bone plate of infraorbital nerve tube and maxillary sinus mucosa thickness.According to the measured data,the best site was chosen for maxillary floor elevation via lateral window with simultaneous placement of dental implants.Finally,beagle dog model was established without extraction and without cutting off the infraorbital nerve and blood vessels.CBCT was taken immediately post operation to test the effect of operation.3、12 beagle dogs were designed as split-mouth study.The right maxillary sinus was set as the experimental group and was executed the modified maxillary sinus floor elevation via a 5mm diameter-round lateral window with simultaneous placement of dental implants.The left maxillary sinus was set as the control group and was executed the maxillary sinus floor elevation via a 10 X 8mm lateral window with simultaneous placement of dental implants.The new bone formation in sinus was analyzed and compared according to Micro CT,tetracycline and calcein fluorescence staining and toluidine blue staining 2 weeks,4 weeks and 8 weeks post operation.Results:1、The cumulative implant survival rate of the 34 cases underwent modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implants was 100%after 24 months follow-up.There was no bleeding and infection post operation.The perforation rate of sinus mucosa was 5.9%.The ISQ value of the implant intra operation was 55.46 ± 5.81,and the ISQ value was 68.55 ± 3.45 at 6 months post operation,which there was statistical significance.Imaging examination revealed that the mucosa of the maxillary sinus was raised to form tents,which was supported by implants and artificial bone materials.There was no obvious perforation of the mucosa and scattered bone powder.The implant was completely surrounded by artificial bone materials.CBCT imagine showed that the height of alveolar bone increased from 2.63 ± 0.48mm before operation(RBH)to 12.13 ± 0.74mm immediately post operation(Imm-BH),then converted to 11.47 ± 0.73mm at 6 months post operation(6M Post-BH),which was decreased compared with Imm-BH,but there was no statistical significance.The bone height at the apical area of implants was 3.11±0.55mm immediately post operation(Imm-IABH)and 2.59 ± 0.51mm at 6 months post operation(6M Post-IABH).There was no statistical difference.The values of the alveolar bone height and the bone height at the apical area of implants on the panoramicradiographs were the highest immediately post operation,of which the mesio alveolar bone height was 12.65 ± 0.74mm,the distal alveolar bone height was 12.56 ±0.74mm and the bone height at the apical area of implants was 3.02 ± 0.39mm.These data showed downward trend 6 months post the operation,but there was no significant difference compared that immediately post operation.The height change was not obvious 6 months post loading,12 months post loading and 24 months post loading.There was no effect on the alveolar bone height and the bone height at the apical area of implants,whatever it was a mini round or a mini slot.2.Based on the CBCT imaging analysis of 24 beagle dogs,the data at the coronal section corresponding the cusp vertex of PM4 was as follows:the maxillary sinus width was 5.77 ± 0.29mm,the maxillary sinus height was 20.67 ± 1.50mm,the palatal plate thickness was 1.85 ± 0.27mm,the distance from PM4 palatal alveolar crest to maxillary sinus floor was 6.3 ± 0.27mm,the thickness of the upper buccal bone plate of infraorbital nerve tube was 1.75 ± 0.34mm,the thickness of the middle buccal bone plate of infraorbital nerve tube was 0.79 ± 0.04mm,the thickness of the lower buccal bone plate of infraorbital nerve tube was 2.86 ± 0.07mm and maxillary sinus mucosa thickness was 1.09 ± 0.25mm.Based on this locus,the beagle dog model with a circular window with a diameter of 5mm was established without extraction and without cutting off the infraorbital nerve and blood vessels.3.The wound healing was good in the experimental group and the control group,and the implant was stable during the experiment.Micro CT showed that the artificial bone particles were clearly visible in the control group and the experimental group at 2 weeks post operation.The artificial bone particles were fuzzy and new bone trabecula was formed in the experimental group at 4 weeks post operation,while the artificial bone particles of the control group were still clearly visible at 4 weeks post operation and until 8 weeks the new bone appeared around the artificial bone particles.The bone mineral density of the experimental group was significantly different from that of the control group at 4 and 8 weeks post operation.Tetracycline and calcein fluorescence labeling at 2 weeks post operation showed no new mineral bone formed in experimental and control group,while 4 weeks and 8 weeks post operation showed that the calcium deposition rate in the experimental group was faster than that in the control group.Histological analysis showed that there was more new bone formation in the maxillary sinus in the experimental groupat4 weeks and 8 weeks post operation.In the experimental group,a large number of new bone had been grown around the bone particles from the host side at 4 weeks,and even some of the bone particles had been wrapped by the new bone.At 8 weeks,the new bone grew to the artificial bone particles and wrapped the artificial bone particles completely and connected most of the bone particles into a whole through the new bone.Conclusion:1.Modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implants was a minimally invasive operation.It can reduce the range of flap turnover and reduce the trauma of patients and avoid two operations of delayed implant and shorten the treatment time.Moreover,the operation can completely lift the maxillary sinus floor mucosa and achieve the predesigned maxillary sinus bone augementation and simultaneous implant placement.But this operation need to be carried out by skilled surgeons,so as not to increase the incidence of complications such as perforation of the mucous membrane,and even can avoid the injury to the upper alveolar artery.2、The beagle dog model with the maxillary floor elevation via lateral window with simultaneous placement of dental implants at the site corresponding the cusp vertex of PM4 was feasible,which there was no extraction,no nerve cutting off and simultaneous placement of dental implant in the palatal plate in the model.The animal model had the advantages such as the clear positioning mark,the high repeatability,minimally invasive surgery,saving time and cost,which was worthy of promotion.The diameter of the lateral window is less than or equal to 5mm and the new bone tissue can be detected on the window surface at 8 weeks post operation,which was proved that the critical bone defect model of canine maxilla can be established by the circular bone defect of 5mm diameter.3、Compared with the maxillary sinus floor elevation via a 10 × 8mm lateral window with simultaneous placement of dental implants,the mini lateral window not only retained more blood supply and osteogenic cell for maxillary sinus bone regeneration,but also ensure more integrity of the maxillary sinus wall which the artificial bone material,blood and cell factors were not easy to lose and scat from the window.So more new bone was formed in sinus at the early stage post operation in the animal model of modified maxillary sinus floor elevation via a mini-lateral window with simultaneous placement of dental implants.
Keywords/Search Tags:Maxillary Sinus Floor Elevation via Lateral Window, Implant, Alveolar Bone Height, Bone Regeneration
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