| Objectives：Skeletal class Ⅲ malocclusion has always been a difficultand hot subject in orthodontics. The treatment of skeletal class Ⅲ withmandibular deviation is even harder and the final effects are mostly uncertain.Therefore, the research on mandibular morphology of adult patients withskeletal class Ⅲ malocclusion with mandibular deviation has great clinicalsignificance. In the research, we tried to make analysis of the mandibular ofadult patients who were skeletal class Ⅲ malocclusion with mandibulardeviation by CBCT (cone-beam computerized tomography) data, to find itsdifference from individual normal occlusion and to study the mandibularmorphology characteristics of adult patients who were skeletal class Ⅲmalocclusion with mandibular deviation.Methods: The study objects were divided into two groups: twenty adultpatients with skeletal class Ⅲ malocclusion with mandibular deviation (10male,10female,18-31years old with an average age of21.5years) from theDepartment of Orthodontics in Hospital of Stomatology, Hebei MedicalUniversity, from October2010to October2012; twenty students with normalocclusion from Hebei Medical University (10male,10female,18-28yearsold with an average age of20.95years). CBCT slices were taken for eachobject and saved in Dicom form. Invivo5software was used to makethree-dimensional reconstruction and locate marks for the mandibular to linedistance and volume measurements of mandibular and condylar. All thepatients and students would be informed of the study and agree to accept thestudy.In this study, relevant measurements were set basing on mandibularforamen, mental foramen, mandibular body curve point and differentanatomical cross-section: mandibular ramal length, mandibular body length, mandibular total length, posterior part of mandibular body length, anterior partof mandibular body length, hemi-mandibular volume, mandibular ramalvolume, mandibular body volume, angular angle, condylar unit length,coronoid unit length, angular unit length, body unit length, chin unit length,canine area width, canine area heigth, molar area width and molar area heigth.SPSS13.0statistics analysis software was used to make normality test and tomake description via mean (X) and standard deviation (SD) if the statisticsobeyed the normal distribution. Independent sample t-test would be usedseparately in deviation group and normal group to analyze if there was anydifferences in gender; Paired t-text would employed in nomal group anddeviation group to find if there was any differences; Independent sample t-testwould be used separately in deviation group and nomal group to find if therewas any differences between the two groups. On the contrary, we madedescription via median (M) and interquartile range (Q) and made analysis byWilcoxon rank and inspection (inspection level α=0.05).Results:1The independent sample t-test showed that gender did not affect theresults.(P>0.05).2Relevant hard tissue measurements for students in normal groupshowed that there was no statistical meaning in the measurements of thecondylar width, mandibular ramal length and mandibular body length.3The relevant hard tissues measurements for the patients in deviationgroup showed that: there was statistical difference between nondeviated sidecondylar unit length (44.22±3.71mm) and deviated side condylar unit length(43.43±3.69mm)(P<0.05); there was statistical difference betweennondeviated side angularl unit length (25.18±3.48mm) and deviated sideangular unit length (24.48±3.65mm)(P<0.05); there was statisticaldifference between nondeviated side body unit length (64.45±3.80mm) anddeviated side body unit length (63.10±3.90mm)(P<0.05); there wasstatistical difference between nondeviated side posterior part of mandibularbody (70.54±4.43mm) and deviated side posterior part of mandibular body (69.17±4.09mm)(P<0.05); there was statistical difference betweennondeviated side angular angle (116.4±6.2°) and deviated side angularangle (118.7±5.5°)(P<0.05); there was statistical difference betweennondeviated side mandibular ramal length (63.69±6.20mm) and deviatedside mandibular ramal length (62.17±6.22mm)(P<0.05); there wasstatistical difference between nondeviated side mandibular total length (128.85±6.15mm) and deviated side mandibular total length(127.07±6.63mm)(P<0.05); there was statistical difference between nondeviated sidehemi-mandibular volume (26.21±4.64cm3) and deviated sidehemi-mandibular volume (25.27±4.58cm3)(P<0.05); there was statisticaldifference between nondeviated side mandibular ramal volume (7.97±1.72cm3) and deviated side mandibular ramal volume (7.31±1.74cm3)(P<0.05);there were no statistical differences among mandibular body length,mandibular body volume, anterior part of mandibular body length, coronoidunit length, chin unit length, canine area heigth, canine area width, molar areaheigth and molar area width.4The analysis of bilateral differences for nomal group and deviationgroup showed that: there was statistical difference in the diversity of condylarunit length between normal group (-0.15±1.11mm) and deviation group(0.78±0.94mm)(P<0.05); there was statistical difference in the diversity ofbody unit length between normal group (-0.33±0.94mm) and deviationgroup (1.35±0.89mm)(P<0.05); there was statistical difference in thediversity of posterior part of mandibular body between normal group (0.01±0.45mm) and deviation group (1.37±2.30mm)(P<0.05); there was statisticaldifference in the diversity of angular angle between nomal group (0.1±1.2°)and deviation group (-2.3±1.5°)(P<0.05); there was statistical difference inthe diversity of mandibular ramal length between nomal group (0.15±0.53mm) and deviation group (1.52±0.98mm)(P<0.05); there was statisticaldifference in the diversity of mandibular total length between normal group(-0.04±1.09mm) and deviation group(1.77±1.58mm)(P<0.05); there wasstatistical difference in the diversity of hemi-mandibular volume between normal group (0.09±0.71cm3) and deviation group (0.94±1.09cm3)(P<0.05); there was statistical difference in the diversity of mandibular ramalvolume between normal group (0.10±0.45cm3) and deviation group (0.66±0.77cm~3)(P<0.05); there were no statistical differences in the diversity ofmandibular body length, mandibular body volume, anterior part of mandibularbody length, coronoid unit length, angular unit length, chin unit length, caninearea heigth, canine area width, molar area heigth and molar area width.Conclusion：1The bilateral condylar, mandibular ramal and mandibular body ofadult with individual normal occlusion show good symmetry.2There are asymmetry on condylar and mandibular ramal in adultpatients with skeletal class Ⅲ malocclusion with mandibular deviation.Deviated condylar and mandibular ramal are smaller than the offside; theposterior part of mandibular body are slightly asymmetric while the anteriorpart of mandibular body are almost symmetrical. |
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