| Objective:The thickness of the Goat maxillary sinus mucous membrane was measured in imaging by the cone beam computed tomography(CBCT),and measurement of maxillary sinus membrane thickness(SMT)after soaking in 0.9% normal saline,fixation with 10% neutral formalin solution and histological treatment,then compare the differences of four groups.At the same time,the elastic modulus of mucosa was measured by mechanics to compare the difference of mucosa deformation between fresh and fixed state,so as to provide guidance for maxillary sinus floor lifting and theoretical basis for animal experimental selection of maxillary sinus.Methods:The 15 fresh goat heads of either gender,aged 1-year-old,were photographed by CBCT,the data were imported into Simplant pro17 in DICOM format,the maxillary sinus was divided into normal group and pathological group,and the thickness and density of the lateral wall bone(bone thickness imaging group),as well as the SMT were measured on radiographic(SMT1).Lateral wall bone thickness was measured in vitro(bone thickness vitro group)after the maxillary sinus was dissected and spreaded according to the image.At the same time,the fresh maxillary sinus mucous membrane was placed in 0.9% normal saline at room temperature for 5 minutes,and then made into 3 pieces of mucosa strips larger than 10 mm * 10 mm,and the thickness of three mucosal strips was measured(SMT2),respectively,two of the fresh maxillary sinus mucous membrane soaked in 0.9% normal saline were fixed with 10% neutral formalin solution for 24 hours and then the thickness was measured(SMT3).One of the maxillary sinus mucous membrane fixed with 10% neutral formalin was made into paraffin-embedded tissue sections,and then the thickness of the histological mucosa was measured in soft of Image J(SMT4).The remaining one was soaked in 0.9% normal saline(fresh group)and 10% neutral formalin solution(fixed group)was used to measure the tensile strength of the maxillary sinus mucous membrane by Handpi force gauge,respectively.And then statistical analysis of the differences and correlation between the groups by SPSS 21.Results:1.The thickness of the lateral wall of the maxillary sinus in the imaging group and the in vitro group were 2.47 ± 0.22 mm and 1.48 ± 0.18 mm,respectively,there was significant difference between the two groups(P<0.05),the imaging results were 1.68 times larger than in vitro.There was difference between the normal group(2.54 ± 0.21mm)and the lesion group(2.36 ± 0.19mm)(P < 0.05).2.The mean bone density was 587.93 ± 141.19 HU in maxillary sinus,and there was significant difference between normal group(687.35 ± 52.88 HU)and lesion group(416.20 ± 39.49 HU)(P < 0.05).And there was a positive correlation between bone density and bone thickness(r=0.623,P=0.000).3.In the measurement of mucous membrane thickness,the SMT1,SMT2,SMT3 and SMT4 were 0.81±0.33 mm,0.70±0.35 mm,0.68±0.34 mm and 0.67±0.33 mm,respectively.There were differences between the SMT1 and the other three groups(P < 0.05);the SMT of real specimen were enlarged by 1.67 1.21 times on CBCT,the thickness of fresh tissue of maxillary sinus mucous membrane was reduced by 3.7% after fixation with 10% neutral formalin solution.4.The mean mucous membrane thickness in the normal group,the SMT1,SMT2,SMT3 and SMT4 were 0.65±0.07 mm,0.54±0.11 mm,0.52±0.11 mm and 0.51±0.12 mm,respectively.There was a difference in mucosal thickness between the image group and the fresh,fixed and histological groups(P < 0.05),and there was no difference between the SMT3 and SMT4(P > 0.05).5.The mean mucous membrane thickness in the lesion group,the SMT1,SMT2,SMT3 and SMT4 were 1.41±0.04 mm,1.33±0.20 mm,1.28±0.19 mm and 1.24±0.17 mm,respectively.6.In the study of mucosal deformation mechanics,the average tensile length and tearing force in the fresh group were 11.90±5.03 mm and 5.94± 1.66 N,respectively,and that in the fixed group were 4.73±1.21 mm and 3.95± 1.13 N,respectively.there was difference in tensile length and tearing force of mucous membrane between the fresh and fixed group(P < 0.05),the thickness of the maxillary sinus lateral wall bone and mucosa were enlarged by 1.67 times and 1.21 times,respectively.7.In the normal group,the mean tensile length of mucous membrane was 14.05±2.98 mm and 5.08±1.09 mm,and the mean tearing force was 6.42±1.49 N and 4.06±1.22 N in the fresh and the fixed group,respectively.The mucosal deformation and external force was 0.46N/mm in fresh group and 0.80N/mm in fixed group,there was difference in two groups(P < 0.05).8.In the lesion group,the mean tensile length of mucous membrane was 3.74±0.47 mm and 3.39±0.46 mm and the mean tearing force was 4.09±0.64 N and 3.49±0.54 N in the fresh and the fixed group,respectively.there was no difference in tensile length and tearing force of mucous membrane between the fresh and fixed group(P > 0.05).Conclusions:1.The real specimen measurement results of the thickness of the maxillary sinus lateral wall bone and mucosa tissues is magnified in CBCT.2.The thickness of fresh tissue of maxillary sinus mucous membrane was reduced after fixation with 10% neutral formalin solution.,which can be ignored.The thickness of fresh maxillary sinus mucous membrane and after it was fixed with 10% formalin neutral solution and histological treatment were different but no significant.3.The deformation and load capacity of fresh maxillary sinus mucous membrane are positively correlated with mucosal thickness,the deformation and load capacity of fresh maxillary sinus mucous membrane after fixed formalin solution was reduced.4.It is feasible to mechanical measurements of the thickness of maxillary sinus mucous membrane without pressure.5.The bone thickness,bone density and mucosa thickness of the lateral wall of the maxillary sinus in goats are close to that of human beings,the goat is suitable for the simulation experiment of maxillary sinus lifting technology. |
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