| Research background:Studies have found that deformities of the lips in adults[43]and children[42]have a negative psychological impact.A lot of poor soft tissue profile is closely related to malocclusion.More and more orthodontic patients tend to improve their appearance while correcting malocclusion.Therefore,the aesthetic degree of soft tissue profile has become the common focus of patients and doctors.Orthodontists’ consideration of soft and hard tissue coordination plays an important role in the design of the scheme.Previous studies have developed controversial consistency on the growth of the corresponding soft and hard tissue.Dr.Downs’s view that,in the case of a coordinated hard tissue structure,the view that soft tissue is considered to be evenly covered over hard tissue to obtain a coordinated soft tissue profile has persisted for a long time.In modern orthodontics studies,many scholars believe that the consistency of soft and hard tissue growth and development is open to question,but hard tissue has a certain influence on soft tissue profile.They believe that the mutual influence of soft and hard tissues is only half of the determining coefficient and the other half depends on the developmental characteristics of the soft tissue itself.The shape of the nose,chin,and lip plays a decisive role in the shape of the soft tissue profile.Some foreign scholars have proved that all three have growth changes during the growth and development period,but their growth volume decreases in turn.As a result,the aesthetic evaluation of side appearance of adolescent patients and adult patients is different,that is,adolescents have relatively obvious lips and adults have relatively shrinking lips more in line with the aesthetic needs.However,this phenomenon is only related to soft tissue growth and development,but not necessarily related to the growth of hard tissue.The purpose of this study was to investigate the relationship between soft and hard tissues and the characteristics of these patients by comparing the numerical changes of soft and hard tissues before and after orthodontic treatment in patients with Class ⅡDivision 2.Objective:Comparative analysis the differences of the vertical types and perioral soft tissue data changes before and after orthodontic treatment.Study the numerical change in clinical significance.Methods:Complete cases with Class Ⅱ Division 2 malocclusion were selected since 2012 to 2017 as the research samples in the second affiliated hospital of Dalian medical university orthodontic department.According to diagnostic criteria,there are 30 patients including 10 high angle patients(8 males and 2 females),10normal angle patients(4 males and 6 females).10 low angle patients(9 male and 1 females)were selected.Lateral cephalogram X-ray film was taken before and after treatment.For each individual case,the number of measured markers in the lateral cephalogram X-ray was 16,the measurement item was 14,8 jaw bone measurement items,2 teeth measurement items,4 perioral soft tissue are included.The measured value was obtained by using the uniform x-ray image measurement method.The subjects were treated before and after treatment,then,according to the measured values,each group was divided into the high angle group,the normal angle group and the low angle group according to the different vertical facial types.Finally,the data after treatment were subtracted from the data before treatment,and the changes of soft and hard tissues around the oral cavity in adult patients with Angle 112 classification were studied before and after orthodontic treatment.Results:This experiment has statistical significance in the comparison of all the measurement results(P<0.05),which has 13 items(including 7 sclerous tissues items and 6 soft tissue itmes).There were significant statistical significance(P<0.01)data in 9 items(including 6 sclerous tissues items and 3 soft tissue itmes).1.Statistical results of tissue changes before and after treatment in high angle group:Hard tissue:The change of SNA after treatment was negative(P<0.05),suggesting that the anterior maxilla of the high angle group had a far median shift after treatment compared with that before treatment.After SNB treatment,there was a significant negative change(P<0.01),suggesting that the anterior part of mandibular alveolar bone had a far median shift after treatment in the high angle group compared with before treatment.There was no statistical difference in the negative change after treatment with ANB.The decrease of SNA and SNB suggested that the protrusion of facial profile in high angle group decreased after treatment,but the vertical position relationship of mandible and mandible changed,but the trend was not obvious.There was no statistical difference in the change of mandibular plane angle after GoGn-SN treatment,suggesting that the mandibular plane angle in the high angle group increased after treatment,but the trend was not obvious.There was significant difference in the negative change of S-Go after treatment(P<0.01),suggesting that the height of high angle group decreased after treatment.There was no statistical difference in the positive change of N-Me after treatment,suggesting that the anterior height of the high angle group increased after treatment,but the trend was not obvious.There was no statistical difference in the change of Pog-NB,suggesting that the distance from the anterior chin point to NB decreased in the high angle group,but the difference was not significant.The change of S-Go/N-Me after treatment was significantly negative(P<0.01),suggesting that the ratio of anterior height to anterior height decreased in the high angle group after treatment,while the mandibular plane angle(although there was no statistical difference,but the value was positive)increased.indicating that the anchorage in the high angle group was difficult to control.There was no statistical difference in the change of UI-NA after treatment,suggesting that the angle between upper anterior teeth and NA in high-angle group increased,but the trend was not obvious.After LI-NB treatment,there was no significant difference in the change of positive value,suggesting that the angle between anterior lower teeth and NB in the high angle group increased,but the trend was not obvious.Soft tissue:After ULP treatment,the change was negative(P<0.05),suggesting that the upper lip thickness of the high angle group decreased after ULP treatment.After LLP treatment,the change was negative(P<0.05),suggesting that the thickness of lower lip decreased in the high angle group.The change of Sn-H after treatment was positive(P<0.01),suggesting that the distance from inferior nasal point to H line in the high angle group increased after treatment.There was no statistical difference in the negative change of LL-H after treatment,suggesting that the distance from the lower lip protrusion to H line was decreased in the high angle group,but the trend was not obvious.2.Statistical results of tissue changes before and after treatment in the mean angle group:Hard tissue:There was no statistical difference in the positive value of change after SNA treatment,suggesting that point A moved forward in the mean angle group after treatment,but the trend was not obvious.There was no significant difference in the negative change after SNB treatment,suggesting that point B in the mean angle group moved back after treatment,but the trend was not obvious.There was a significant difference in the change of ANB after treatment(P<0.01),suggesting that the average angle group increased after ANB treatment,and the convex shape improved.There was no statistical difference in the negative change of GoGn-SN after treatment,suggesting that the mandibular plane angle in the mean angle group decreased,but the trend was not obvious,which accorded with the treatment expectation.The change of S-Go after treatment was positive(P<0.01),suggesting that the average angle group increased after treatment.After treatment,the change of N-Me was positive(P<0.01),suggesting that the height of mandibular plane was counterclockwise and the height of mandibular plane was counterclockwise.Rotation tendency and anchorage are well controlled.There was no statistical difference in the positive change of Pog-NB after treatment,suggesting that the distance from the anterior chin point to NB increased after treatment in the mean angle group,but the trend was not obvious.The change of S-Go/N-Me after treatment had no statistical difference.Combined with the increase of S-Go and N-Me in the mean-angle group,the increase of S-Go and N-Me after treatment in the mean-angle group was slightly higher than that in the front,but the trend was not obvious.There was no significant difference in the change of UI-NA after’ treatment,suggesting that the angle of upper anterior teeth and NA increased after treatment,but the trend was not obvious.After LI-NB treatment,there was no significant difference in the change of positive value.The angle between anterior teeth and NB increased after treatment in the mean angle group,but the trend was not obvious.Soft tissue:After ULP treatment,there was a significant negative.change(P<0.01),suggesting that the upper lip thickness in the mean angle group decreased after ULP treatment.After LLP treatment,there was a significant negative change(P<0.01),suggesting that the thickness of lower lip in the mean angle group decreased after LLP treatment.There was significant difference in the negative change of Sn-H after treatment(P<0.05),suggesting that the distance from the inferior nasal point to the H line in the mean angle group decreased after treatment.There was no significant difference in the positive value of LL-H after treatment,suggesting that the distance from the lower lip protrusion to H line was increased in the mean angle group after treatment,but the trend was not obvious.3.Statistical results of tissue changes before and after treatment in low angle group:Hard tissue:There was no significant difference in the positive value of SNA after treatment.suggesting that the anterior maxilla of the low angle group had a near-median shift after treatment,but the trend was not obvious.There was no significant difference in the positive value of changes after SNB treatment,suggesting that the anterior part of mandibular alveolar bone had a near-median shift after SNB treatment,but the trend was not obvious.There was no significant difference in the positive value of ANB after treatment,suggesting that the protrusion of the low angle group decreased and the facial shape improved after treatment,but the trend was not obvious.There was no significant difference in the negative change of GoGn-SN after treatment,suggesting that the mandibular plane angle decreased and the mandibular plane was reversed in the low angle group,but the trend was not obvious.There was no statistical difference in the positive change of S-Go after treatment,suggesting that the change of S-Go after treatment was higher in the low angle group than in the low angle group pretreatment.There was no significant difference in the positive value of N-Me after treatment.Combined with the increase of S-Go,the height of the low-angle group increased before and after treatment,and the height of the lower 1/3 increased,which accorded with the treatment expectation,but the trend was not obvious.There was no statistical difference in the change of Pog-NB,suggesting that the distance from the anterior chin point to NB increased in the low-angle group,but the trend was not obvious.The change of S-Go/N-Me after treatment had no statistical difference,suggesting that the mandibular plane angle had a decreasing trend in the low angle group after treatment,while the mandibular plane angle had an increasing trend in the posterior and anterior height,indicating that the lower 1/3 height had an increasing trend,which was in line with the treatment expectation.There was no statistical difference in the change of UI-NA after treatment,suggesting that the angle between upper anterior teeth and NA in low-angle group increased,but the trend was not obvious.After LI-NB treatment,there was no significant difference in the change of the positive value,suggesting that the angle between lower anterior teeth and NB increased in the low angle group,but the trend was not obvious.Soft tissue:There was no significant difference in the negative change after ULP treatment,suggesting that the upper lip thickness in the low angle group decreased after ULP treatment,but the trend was not obvious.After LLP treatment,there was no significant difference in the positive value,suggesting that the thickness of lower lip increased in the low angle group,but the trend was not obvious.There was no significant difference in the positive value of Sn-H after treatment,suggesting that the distance from inferior nasal point to H line increased in the low-angle group,but the trend was not obvious.There was no statistical difference in the negative change of LL-H after treatment,suggesting that the distance from the lower lip protrusion to H line was decreased in the high angle group,but the trend was not obvious.Conclusion:1.For Angle Ⅱ2high angle patients,mandibular plane is prone to anteversion before and after orthodontic treatment.Clinically,vertical support should be well protected for such high angle patients.2,In Angle Ⅱ2patients with high mean angle,the thickness of lip tends to decrease after correction,but the lower lip tends to decrease more in patients with high angle than in patients with upper lip.More upper anterior teeth need to be erect and coordinated profile in clinic;the upper lip of patients with equal angle is smaller than that of lower lip,and the recovery of upper anterior teeth should be less than that of patients with high angle. |
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