| Angle Class?malocclusion in North America in the crowd incidence is 0.8%to 4.2%,the incidence of Japan is 13.6%,while the incidence rate in China is 12%.Most of the class ?malocclusion divided into true(bone)and false(functio nal).There are also divided according to the pathogenesis of dental ?malocclus ion,skeletal ?malocclusion and functional ?malocclusion.Skeletalmalocclusio n incidence is about 5% to 14%.According to scholars statistics,in skeletal ?malocclusion,the maxillary posterior accompanied by shrinkage,mixed dentition,13%,permanent dentition,34%.Clinical manifestations is the central depression of face,after maxillary shrink or normal,mandibular protrusion or normal,front tee th columnsor total pressure column against the teeth.This bony face,with age,i f it does not interfere there is increasing trend,and the face in the crowd this t ype is the least likely to be accepted,they tend to affect the function and menta l health of the patient.Skeletal anterior crossbite children in our country,maxilla ry hypoplasia with mandibular excessive mixing deformity more common.Theref ore,such patients early interference is necessary.Protraction is commonly used in clinical treatment methods has been clinicall y proven to effectively improve maxillary hypoplasia,promote the development o f the upper jaw.For patients with narrow maxillary arch,promoting the use of combined maxillary protraction expand,before and after to solve maxillary hypop lasia,while the width has also been improved.Many experiments and clinical st udies have shown that protraction in conjunction with screw expansion device,n ot only to achieve better results,the treatment cycle will be reduced accordingly.So now in clinical protraction in conjunction with screw expansion device is rel atively common,but some class ? patients after crossbite covering shallow,jaw or jaw spee steeper curvature crowded,just carry on maxillary expansion and p rotraction is very difficult to solve,and for patients with maxillary severe cong estion,Often needs to expand dental arch for clearance as soon as possible,so t hat the lower jaw and the upper jaw is not a good match.For such cases,we a pplied the Professor GuizhiZhao improved mandibular screw expansion device on the mandibular arch is appropriate to expand to improve spee curve and mandi bular crowding and other problems to solve,for the remaining gap may accept within the anterior teeth.Previous studies did not involve such problems,in our study is to investigate the mandibular arch expansion combined protraction in Cl ass ? malocclusion in clinical application.Research PurposesProtraction combined with maxillary expand is a commom method to treate the growth and development of skeletal crossbite patients,maxillary promoted,not only from the length of the maxilla to stimulate growth,but also on a certain amount of from the width of the jaw to stimulate the development.For serious maxillary arch crowding patients often need overstimulation arch,which may lead to the mandibular arch width does not match,for such patients,our exploration will expand the application of mandibular spiral,Through the analysis of the results summarized on the scope of the maxilomandibular arch expansion combined with protraction in Angle class? malocclusion deformity clinical efficacy application,to provide a method of treatment for such patients.Research MethodsThe Experimental selected 12 patients from Air Force General Hospital Orthodontics in past seven years.Class ? mild skeletal facial types,ANB <0o,occlusal relationship is mesial;maxillary arch crowding amount average 8.12 ± 1.34 mm,the mandibular arch crowding amount average2.12±1.34mm;before and after treatment showed no skeletal dysplasia,normal periodontal tissue,no significant mandibular protrusion.For the treatment of upper and lower arch expansion combined protraction;at the end of treatment Patients with dental neat and good occlusion.The tooth models and skull radiographs were taken before treatment and at the end of fixed orthodontic.Model for measuring content before and after treatment of the model year of treatment on mandibular model cusp 3-3 pitch,and the distance between the central fossa 4-4,5-5,6-6,mainly reflecting the patients before and after treatment arch width arch width to maintain the status change and after treatment.X-ray measurements included SNA,SNB,ANB,L1 / MP,U1 / NA,MP / SN,U1 / SN,U1 / NB and other indicators,which reflect hard tissue changes,and Holdaway,Burstone and Ricketts' measurements which reflected the lip and soft tissue changes.All models were measured by the same surveyors and measured twice within a week,taking the average of the two measurements for the final result.All X-ray film measured by the same investigator completed within a half months.A same radiograph was measured twice in a half month,if there are significant differences in the two measurements for X-ray re-measurement.The average of the two measurements is the measurement result.Data were measured by SPSS13.0 statistical software in paired t test,to analyze before and after treatment arch changes and maxillofacial and soft tissue changes.Results1.12 cases of patients before and after treatment of the upper and lower arch width changes significantly,were statistically significant.Maxillary canines,first premolars,second premolars and the first inter-molar width respectively increased 3.39 ± 0.59 mm,4.81 ± 1.04 mm,6.56 ± 2.25 mm,3.12 ± 1.15 mm.Mandibular canines,first premolars,second premolars and the first inter-molar width respectively increased 3.81 ± 0.90 mm,5.14 ± 1.15 mm,6.59 ± 0.81 mm,3.80 ± 0.67 mm.Arch width showing an overall increase in the amount of premolar region> molar area> canine.The arch widthchanges of premolar and molar region make a significant arch form change occurred.2.Changes significantly in sagittal skeletal,A point forward about 2.55 mm,SNA increased 2.16 ± 0.29 °,SNB reduced 1.21 ± 0.36 °,ANB increased 3.66 ± 0.22 °,changes were statistically significant.Description maxillary advancement,mandibular there is a tendency to retreat.FH-MP and MP-SN angle was increased,Y-Aix increased 3.31 ± 1.37 °(P <0.05)lower jaw tips downward backward rotation.High above in the vertical direction and the front have a high increase in the following sense,increased 2.36 ± 0.36 mm and 5.17 ± 1.65 mm.3.Dental aspects: Overjet,Wits value difference variation was significant(P <0.05),increased by 5.33 ± 0.54 °,4.31 ± 2.33 mm.And the cutting teeth obliquity relevant indicator U1 / SN,U1-NA(mm),were significantly increased(P <0.05),increased 5.72 ± 1.37 °,1.61 ± 0.50 mm,U1 / L1 decrease 4.72 ± 1.75 °,suggesting anterior teeth appear compensatory pour lip.Although the three indicators after treatment with the axis-cut teeth of each index were increased but remained within the normal range occurred.L1 / NB average reduction of 2.19 ± 0.99 °(P <0.05),P-NB average increase of 1.09 ± 0.28(P <0.05)less than the normal range L1 / SN,L1 / MP,L1-NB increase was not statistically significant,indicating that the next axis inclination of the anterior teeth should be meaningless changes,it does not appear to prove lower incisors compensatory tongue backward.4.Soft tissue changes after the treatmen: The average distance from the upper lip to line E and H increase about 1.43±0.52 1.15±0.32,there is statistically significant change,Description upper lip moves forward,increasing the fullness of the lips.Lower lip with respect to the E line H line distance decreased by 1.07 ± 0.98,1.75 ± 2.11.The Lower lip bump into Sn-Pg 'from the reduction of 1.21 ± 1.22,were statistically significant,indicating that the lower lip with respect to the Sn-Pg' adduction.Nasolabial angle to reduce meaningless,but the angle within the normal range.Sn-H,H angle increases were statistically significant,the upper lip also suggested moving forward.Chin lips reduced 6.06 ± 0.92 was statistically significant.Changes in the indicators show improvement after the treatment of soft tissue analysis.5.Conclusion1.Maxillary expansion combined with protraction,stimulate maxillary develo pment obviously,dental arch width increase significantly,while stimulating the de velopment of the maxillary solve the crowding problem.2.Premolar district width increases most significantly,to provide sufficient clearance to solve crowding.3.The expansion of the mandibular arch adaptability,dental arch width incr eases,spee curve improved to solve the mandibular dentition slight crowding.M axillomandibular arch expansion technology can facilitate alveolar bone remodelin g.4.Meanwhile Palatal expansion combinedwith the fixed appliance,the flexibility of treatment in arch expansion device can be increased,to resist the anchorage molar distalization can increase the dental arch perimeter,non extraction treatment of Serious maxillary crowding patients will becoming possible.5.Use the protraction with growth modification treatment of maxillary arch expansion is carried out,can significantly guide the growth of the jaw and move forward to correct the patient's malocclusion and improve the patient's soft tissue profile.Especially for Class III by the contraction caused by the maxillary malocclusion patients is an effective clinical treatment.6.Protraction combined with maxillamandibular expansion,soft tissue surfac e accuracy improved significantly,maxillary soft tissue to move forward,after m andibular rotation,lower lip protrusion becomes smaller. |
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