| ObjectiveTo investigate the quantitative and qualitive analytical method ofthree-dimensional images of the interproximal interfaces(IPI)of maxillary central incisor scanned by the Micro computed tomography(Micro-CT).Mainly providing the guidance for the interproximal enamel reduction technique and proximal restoration.MethodsThe samples consist 40 interproximal interfaces of 20 maxillary central incisors of ten males and ten females.Silicon rubber impressions were made before and after using elastic separation on the mesial and distal IPI.Then scanning and reconstructing the study casts by the Micro-CT.The three-dimensional images were then managed and analyzed as follows:1.Using the Mimics and 3-matic software to process the initial images,to build up the reference plane and to acquire the three-dimensional images of IPI in superimposition method.2.Surface area of IPI,the height of IPI(H),the height of IPI to reference plane(RP-H),the height of IPI to gingival margin(H-GM),the width of IPI(W),the labial width(LW),the palatal width(PW),the incisal embrasure angle(IEA),the gingival embrasure angle(GEA),the labial embrasure angle(LEA)and the palatal embrasure angle(PEA)were analyzed.Results1.For the surface area of mesial IPI,there was no significant difference between each group of male and female:the mean values were 0.71±0.18mm~2and 0.73±0.20mm~2(P>0.05).For the surface area of distal IPI,there was no significant difference between the male and female group:the mean values were 0.63±0.20mm~2and0.59±0.15mm~2(P>0.05).2.(1)For the RP-H,H,H-GM of mesial IPI,there was no significant difference between the male and female group respectively:the mean values in the male group were1.87±0.36mm,1.13±0.11mm,6.92±1.76mm,and the mean values in the female group were1.75±0.33mm,1.11±0.27mm,7.01±2.02mm(P>0.05).For the RP-H,H,H-GM of distal IPI,there was no significant difference between the male and female group respectively:the mean values in the male group were 3.71±0.76mm,1.21±0.30mm,5.12±1.93mm,and the mean values in the female group were 3.75±0.90mm,1.41±0.61mm,4.86±1.55mm(P>0.05).(2)The mean values of RP-H/H/H-GM of mesial IPI was18.85%:11.39%:69.76%,and its values of distal IPI was 37.33%:11.98%:50.69%.3.For the L-W?W?W-P of distal IPI,there was no significant difference between the male and female group respectively:the mean values in the male group were 1.42±0.39mm?0.78±0.36mm?2.81±0.87mm,and the mean values in the female group were1.31±0.51mm?0.81±0.39mm?3.02±1.02mm(P>0.05).The mean value of L-W/W/W-P of mesial IPI was 32.26%:19.07%:48.69%,and its value of distal IPI was28.84%:15.59%:55.59%.4.For the distal IEA,GEA,LEA and PEA of IPI,there were no significant differences among within the group:the median values in the mesial group in male were30.72°,23.41°,43.02°,24.35°,the mean values in the distal group in male were47.67°,35.82°,51.70°,35.38°,the mean values in the mesial group in female were28.18°,23.12°,38.25°,22.18°,and the mean values in the distal group in female were 42.95°,35.31°,42.32°,36.90°.5.The mean shape of mesial and distal IPI of maxillary central incisor was an approximate oval in mesio-distal direction but performed as a oblate letter‘D'in labia-palatal direction.ConclusionQuantitative and quality research on the IPI of the maxillary central incisor could depend on acquiring the three-dimensional IPI images in superimposition method by Micro-CT before and after elastic separating.The conclusions were following:1.Precise three-dimensional IPI images could be acquired in the superimposition method by the Micro-CT before and after elastic separating.2.For the values of surface area,height and width of mesial IPI,there were no significant differences between male and female group(P>0.05).The proximal area should be reshaped as normal embrasure morphology with certain angles when applying interproximal enamel reduction in operation. |
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