Characteristics Of Maxillary Morphology In Unilateral Cleft Lip And Palate Patients And Skeletal Classâ…¢ Patients Compared To Normal Subjects

[Objective]:The study is to build up a three dimensional craniofacial measurement system of the cleft lip and palate patients, and to investigate the anatomical features of maxillae in unilateral cleft lip and palate (UCLP) and patients with maxillary retrusion as well as maxillary retrusion patients without clefts. Additionally, the dissimilarities of retruded maxillae between the UCLP patients and the skeletal classⅢpatients were compared.[Methods]:Craniofacial measurements were carried out among 32 UCLP adult patients with maxillary retrusion (GC),24 adult patients in class III (SNA<80°, ANB<0°) (GⅢ),and 32 normal controls (GN). The CT slice date was from the LightSpeed CT scanner using a high-resolution bone algorithm. The axial images were reconstructed into a 3D video model using Mimics, software, version 16.0. All statistical analyses were conducted by IBM SPSS Statistics software, version 20.0. The independent sample group t test was used to compare means of cleft side and healthy side in GC group, right side and left side in GⅢ and GN groups besides means of GC and GN, GC and GⅢ, GⅢ and GN were compared. The levels of significance were set at P<.05.[Results]:In GC group, distances from literal incisor and canine to sagittal plane were obviously shorter than healthy side(P<.05), while mesiobuccal cusp of maxillary second molar on cleft side was significantly further away from sagittal plane than healthy side (P<.01);the dental arch of the cleft side rotated clockwise and the anterior part collapsed,the dental arch showed a "V" shape; when compared to the GN group, the lengths of A1⊥CP, P3M⊥CP, and P6M⊥CP were significantly shorter in the GC group than in the GN group(P<.01,P<.01,and P<.05, respectively);the anterior and posterior parts of the maxillary length(A1-P3M⊥CP and P3M-P6M⊥LCP) and overall maxillary length (A1-P6M⊥CP)at the dental level were all significantly reduced(P<.01);the interdental widths (M3W, M4W, M5W, and M6W) were obviously more constrictive and from the anterior part up to the first molar, the gap gradually narrowed (P<.01). The maxillary volume(GM) and the volume composed of maxilla and maxillary sinuses(GT) were significantly smaller (P<.01). In the GIII group, length of anterior cranial base (S-N), length of overall cranial base (Ba-N), and ∠BaSN were significantly reduced compared to the other two groups(P<.05). The distances of A1⊥CP, P3M⊥CP, and P6M⊥CP were obviously smaller than in the GN group(P<.01).In addition, P3M-P6M⊥CP and A1-P6M⊥CP was significantly reduced(P<.01). There was no significant difference of the distances of A1⊥CP between the GC and GIII groups (P>.05), while the P3M-CP and P6M-CP in the GIII group were significantly shorter(P<.01, and P<.05, respectively).The anterior and overall maxillary length at the dental level (A1-P3M⊥CP and A1P6M⊥) in the GC group was significantly smaller than that in the GIII group(P<.01, and P<.05, respectively).[Conclusions]:In summary, for the UCLP patients, the decreased prominence of maxillary complex could be mainly caused by the shortened maxillary length, meanwhile posterior position of the maxillary body may have some influence on the maxillary prominence;while for the class III patients, the posterior position of the maxillae was more obvious than the GC group, maxillary retrusion were resulted from malposition and malmorphology on an equal basis. For the UCLP patients, the trend of the dental arch construction from back to front increased, on the cleft side, the dental arch rotated clockwise and the anterior part collapsed, the dental arch showed a "V" shape, but there were no significant differences of dental widths of the class III patients and normal controls.