Pre-maxillary Morphology In The Primary Dentition With Class â…¢ Malocclusion

Objective:To compare the pre-maxillary morphology characteristics of children with Class Ⅲ malocclusion to those of children with normal occlusion during the deciduous dentition phase. This study surveyed the relationship between the pre-maxiliary growth deficiency and Class Ⅲ malocclusion.Materials and Methods:Plaster mold measurements of39children (male15, mean age:4.33years; female24. mean age:4.58years) diagnosed with Class Ⅲ malocclusion were compared with15children (male7, mean age:4.51years; female8, mean age:4.45years) with normal occlusion in the following three areas:the anterior dental arch, the whole dental arch and the posterior dental arch. The measurements include the depth of the dental arch, the width of the dental arch and the area of the palate plate. Student’s t-tests were performed to assess differences between the test (Class Ⅲ) group and the control (normal occlusion) group with SPSS16.0. Results:Significant differences were seen in the following measurements in both male and female groups:depth of anterior dental arch(AD), depth of the whole dental arch(UD), length of the anterior dental arch(UC-C), area of the anterior palate plate(Al,A2,A0), area of the whole palate plate(B1,B2,B0).The measurements of male groups included AD (Class Ⅲ group:9.22±0.94; normal group:10.73±1.08), UD (Class Ⅲ group:26.50±1.19; normal group:28.40±1.29), UC-C (Class Ⅲ group:35.62±2.12; normal group:37.85+2.34), Al (Class Ⅲ group:116.33±22.06; normal group:143.52±19.26), A2(Class Ⅲ group:238.48±24.17; normal group:272.53±25.90), AO (Class III group:177.40±22.20; normal group:208.03±22.24), Bl (Class Ⅲ group:656.61±42.90; normal group:710.68±63.47), B2(Class Ⅲ group:1062.56±57.05; normal group:1129.52±84.68), BO (Class Ⅲ group:859.58±48.23; normal group:920.10±73.83); The measurements of female groups included AD (Class Ⅲ group:8.29±1.02; normal group:10.14±0.98), UD (Class Ⅲ group:25.42±1.36; normal group:27.45±1.70), UC-C (Class Ⅲ group:33.59±1.87; normal group:35.49±1.65), Al (Class Ⅲ group:95.70±16.65; normal group:127.51±16.41), A2(Class Ⅲ group:211.01±22.37; normal group:244.56±23.74), AO (Class Ⅲ group:153.35±18.92; normal group:185.58±18.96), B1(Class Ⅲ group:582.45±40.32; normal group:639.62±60.40), B2(Class Ⅲ group:974.24±58.69; normal group:1038.56±87.72),B0(Class Ⅲ group:778.35±48.44; normal group:840.67±75.25); Significant differences were seen in all measurements except the posterior dental arch depth(PD) between male and female groups with Class Ⅲ malocclusion (p<0.05).Conclusions:The pre-school children with Class III malocclusion suffer from the pre-maxillary sagittal growth deficiency. And male have a larger dental arch than female in the deciduous dentition. Objective:To compare the pre-maxiliary cephalometric characteristics of children with Class III malocclusion to those of children with normal occlusion during the deciduous dentition phase.Materials and Methods:Cephalometric measurements of38children (male16, mean age:4.34years; female22; mean age:4.52years) diagnosed with Class III malocclusion were compared with15children (male8, mean age:4.53years; female7; mean age:4.65years) with normal occlusion in the following two categories:sagittal skeletal analysis and vertical skeletal analysis. Student’s t-tests were performed to assess differences between the test (Class Ⅲ) group and the control (normal occlusion) group with SPSS16.0.Results:Significant differences were seen in sagittal skeletal measurements in male groups: Len(S-A’)(Class Ⅲ group:47.29±2.31; normal group:49.79±2.31), Len(S-ANS’)(Class Ⅲ group:50.88±1.93; normal group:53.33±1.93), Len(PNS-a)(Class Ⅲ group:34.73±1.80; normal group:37.44±1.80), Len(ANS-PNS)(Class Ⅲ group:38.28±1.52; normal group:41.08±1.52), ANB (Class Ⅲ group:1.52±2.02; normal group:6.41±2.02), Convexity (Class Ⅲ group:6.30±4.78; normal group:14.77±4.78), Wits (Class III group:-5.13±2.82; normal group:-0.13±2.82); The sagittal skeletal measurement of female groups included Len(S-Pr’)(Class Ⅲ group:46.21±2.89; normal group:49.41±2.40), Len(S-A’)(Class Ⅲ group:47.15+2.45; normal group:50.24+2.13), Len(S-ANS’)(Class Ⅲ group:49.86±2.31; normal group:54.36±2.32), Len(PNS-a)(Class Ⅲ group:33.17±1.35; normal group:38.89+2.09), Len(ANS-PNS)(Class Ⅲ group:36.07±1.52; normal group:42.74±1.68), Len(ANS-a)(Class Ⅲ group:2.90±0.82normal group:3.86±1.37), SNA (Class Ⅲ group:81.77±2.66:normal group: 84.76±3.67), SNB (Class Ⅲ group:80.75±2.62; normal group:78.39±2.65), ANB (Class Ⅲ group:1.00±2.42; normal group:6.34±1.52), Convexity (Class Ⅲ group:4.64±6.08; normal group:14.23±4.64), Wits (Class Ⅲ group:-4.62±2.05; normal group:-0.81±.64); Significant differences were seen in vertical skeletal measurements in male groups:Y-axis (Class Ⅲ group:59.89±3.52; normal group:64.99±3.52), FMA (Class Ⅲ group:27.11±5.64; normal group:32.61±5.64), FMIA (Class Ⅲ group:69.88±6.34; normal group:60.34±6.34); The vertical skeletal measurement of female groups included N-Me (Class Ⅲ group:82.77±4.68; normal group:87.60±5.08), ANS-Me (Class Ⅲ group:47.39±2.94; normal group:52.33±3.55), Y-axis (Class Ⅲ group:59.23±3.11; normal group:64.11±1.51), FMA (Class Ⅲ group:27.06±4.40; normal group:31.92±3.22), FMIA (Class Ⅲ group:70.69±7.39; normal group:62.37±5.82).Conclusions:The pre-school children with Class Ⅲ malocclusion suffer from the maxillary sagittal growth deficiency.