| Study objectives1.To reconstruct the bone defect model of patients with alveolar cleft and the three-dimensional model of the vomer and measure its morphological parameters,find whether that there is a statistical relationship between the parameters of the vomer and alveolar bone defect in patients with simple alveolar cleft by calculating the three-dimensional parameters of both,and explore the impact of different degrees of alveolar cleft on the vomer.To establish the morphological and quantitative correlation between the vomer and the deformity of the alveolar cleft,and verify the relationship between the volume of the alveolar cleft defect and the morphology of the vomer.2.To carry out mechanical three-dimensional finite element modeling on CT images before and half a year after surgery of bone graft in patients with unilateral alveolar cleft.To analyze the morphological effects of the chewing pressure on the development of the vomer in the maxilla.To explore whether alveolar cleft repair can improve the stress distribution of occlusal pressure in the nasal-maxillary complex.To verify the effect of alveolar cleft autologous bone grafting on the development of the nasal-maxillary complex.3.To complete the follow-up of the clinical trial on secondary excess autologous bone grafting in alveolar cleft,collect CT data of the patients for half a year and one year after operation for digital evaluation,study the osteogenesis efficiency and the effect on the eruption of canines in repairing alveolar cleft with excess autologous bone grafting compared with the equal volume autologous bone grafting,and evaluate the "clinical effect of secondary excess autologous bone grafting technique for alveolar cleft".Study Methods1.Retrospectively collected craniofacial CT data of 40 patients with clinical diagnosis of unilateral alveolar cleft without cleft palate who visited our hospital from January 2019 to September 2021 as the experimental group.In addition,selected craniofacial CT data of 40 normal patients who received maxillofacial CT examination for mandibular angle plastic surgery in our hospital during this period as the control group.Created a three-dimensional model of the vomer with the CT data of the experimental group and the control group by using computer-aided engineering and measured the parameters,and then explored the difference in the volume of the vomer between patients with unilateral alveolar cleft and normal people.Created a three-dimensional model of the alveolar cleft and vomer with the experimental group CT by using computer-aided engineering and measured the parameters,conducted a correlation analysis between the volumes and angels of the vomer and alveolar cleft volume within the experimental group,and then explored the relationship of different degrees of alveolar cleft with the vomer morphology.2.Two 8-year-old patients with clinical diagnosis of unilateral alveolar cleft without cleft palate were included.These patients had no systemic disease and good oral hygiene,and had no other craniomaxillofacial abnormalities.Head CT was taken before the operation,and autologous iliac cancellous bone free grafting was performed in our hospital to repair the alveolar cleft.Six months after the operation,the patients were reviewed in our hospital and CT was taken to check the actual bone formation content.The preoperative and postoperative CT were used to carry out mechanical three-dimensional finite element modeling,and after modeling,the model was loaded with occlusal force to simulate daily occlusal behavior.And observing the distribution of stress and deformation in nasal-maxillary complex of the alveolar cleft model and the bone graft restoration model.3.A randomized single-blind controlled trial design was adopted,and 30 patients with alveolar cleft were enrolled.The bone defect volumes of 30 cases of unilateral alveolar cleft were measured by computer-aided engineering software.After accurate measurement of the defect volume before operation,the volume of iliac cancellous bone grafting was set at three levels,that is,the volume ratio of the bone graft to the bone defect was 1:1,1.25:1,and 1.5:1,respectively.According to the volume of bone graft,the patients were randomly divided into 3 groups for alveolar cleft repair with bone grafting.After operation,the CT three-dimensional reconstruction method was used to visually and quantitatively evaluate the clinical effect,including the bone formation ratio and canine eruption.Results1.There were 40 patients in the experimental group(19 males,21 females;average age 23.00±1.11(16-49 years)),and 40 patients in the control group(23 males,17 females;average age 27.35±0.95(16-51 years)).There was no statistical difference between the two groups in terms of age and sex.In this study,the nasal septum of the patients in the experimental group was all deviated to the side of the cleft,and the number of cases in the experimental group with the nasal septum deviated to the left was(31/40),and the number of cases deviated to the right was(9/40);in the control group,the number of cases with the nasal septum lightly deviated to the right was(19/40).and the number of cases with a slight deviation of the nasal septum to the left was(21/40).The vomer volume(VV)in the experimental group(1595.35±48.45 mm3)was significantly higher than that in the control group(1043.2±164.976 mm3)[P<.0001];the deviated septal angle(DSA)in the experimental group(13.099±7.0°)was significantly higher than that in the control group(3.4398±1.74°)[P<.0001].In the experimental group.VV was significantly correlated with DSA and alveolar cleft volume(ACV):(VV&ACV:r=0.886.P<.0001:DSA&ACV:r=0.543.P<.0001),and DSA was also significantly correlated with VV(DSA&VV:r=0.582,P<.0001).2.The occlusal force was loaded in two cases of craniofacial bone models,and the stress values of marked points of orbital rim.infraorbital rim.outer orbital rim,zygomatic arch,upper molar,and alveolar bone formation were collected.The stress is the Von Mises stress(S.mises).The overall stress at the middle of the maxilla in the two models increased slightly after bone grafting:the stress change of the inner orbital rim(+4.8%/+24%);the stress change of the inferior orbital rim(+5.8%%/+22%);stress changes on the outer orbital rim(+2.2%/+4.6%);stress changes above the molars(+3.5%/+4.8%),decreased stress at Vomer-premaxilla suture(-23.8%/-60%).However,the new formation bone in the alveolar cleft all bear the occlusal stress(+3.4Mpa/+5.1 Mpa).3.In this study,30 patients were enrolled,including 9 cases in the equal volume bone graft group(7 males,2 females:average age:10±1.22 years;age range:8-12 years old).12 cases in the 1.25x excess bone graft group(5 males,7 females:average age:9.5±1.09;age range:8-12 years),9 cases in the 1.5x excess bone graft group(4 males,5 females;average age 9.67±1.41;age range 8-12 years).In this study,there was no statistical difference in the bone formation ratio of the three groups after half a year and one year later,and there was no statistical difference in the bone formation ratio of the three groups after one year.However,the ratio of canine eruption among different bone graft groups was significantly different:including(1/9)cases with canine eruption in the equal volume bone graft group,(3/12)cases with canine eruption in the 1.25x bone graft group,and(6/9)cases with canine eruption in the 1.25x bone graft group.The ratio of canine eruption in the 1.5x bone graft group was significantly higher than that in the 1.25x and equal volume bone graft group,and the canine eruption speed of the affected side was faster than that of the healthy side.Conclusion1.The vomer volume and deviated septal angle in patients with unilateral alveolar cleft were significantly higher than those in controls.In patients with unilateral alveolar cleft without cleft palate:(1)the volume of alveolar cleft defect was correlated with the degree of vomer deformity.The larger the volume of the alveolar cleft,the higher the volume of the vomer and the larger the angle of deflection.(2)The volume of the vomer bone in males is significantly higher than that in females,and the volume of the vomer bone increases with age.2.The bone graft block formed by autogenous bone grafting can improve the stress distribution of the occlusal force on the maxilla of patients with alveolar cleft.After half a year of bone grafting,the stress of the Vomer-premaxilla suture decreased significantly,while the stress in the newly formed bone in the alveolar cleft region.And after the eruption of canines,the stress improvement at the middle of the opposite face and in the cleft is more obvious,which is more beneficial to stress conduction in the cuspid area3.Compared with the equal volume autologous bone graft,excess autologous bone graft had no effect on the osteogenic efficiency of alveolar cleft repair surgery,but excess bone graft could promote the eruption of canines in the maxillary bone of the affected side,and the eruption speed was faster than that of healthy side. |
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