***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The aim of this study was to evaluate and compare the effects of activator and Twin Block ( TB ) appliances on the soft tissue profile . The study included 50 skeletal Class II patients ( 25 girls and 25 boys , mean age : 11.9 + /- 0.16 years ) who were r and omly allocated to one of two functional appliance treatment groups . The control group included 25 untreated skeletal Class II patients ( 13 boys and 12 girls , mean age : 10.11 + /- 0.91 years ) . Data were obtained from st and ardized lateral cephalograms taken at the beginning ( T0 ) and end ( T1 ) of appliance wear . The mean treatment time was 9 months for the activator group and 8 months for the TB group . The observation period of the control group was 8 months . Soft tissue profile changes were evaluated by means of 12 linear and five angular measurements . The groups were compared at T0 and T1 using analysis of variance , and treatment/observation differences ( T1-T0 ) were evaluated with the Kruskal-Wallis test . Treatment changes in both appliance groups differed significantly ( P < or = 0.001 ) from those in the control group , except for Ss-y , Ls-y , Li-E , and A-y measurements in the TB group and Ls-y , Li-E , nasolabial angle , and A-y measurements in the activator group . When the effects of the two appliances were compared , significant differences were observed only for SS-y ( P < or = 0.05 ) , Ss-E ( P < or = 0.05 ) , Si-E ( P < or = 0.05 ) , and nasolabial angle ( P < or = 0.01 ) . The effects of the activator and TB appliances on the soft tissue profile were similar ; both significantly changed the soft tissue profile This study evaluated the effectiveness of early orthodontic treatment with the Twin-block appliance for the developing Class II Division 1 malocclusion . This multicenter trial was carried out in the United Kingdom . A total of 174 children , aged 8 to 10 years old , with Class II Division 1 malocclusion were r and omly allocated to receive treatment with a Twin-block appliance or to an untreated , control group . Data were collected at the start of the study and 15 months later . Results showed that early treatment with Twin-block appliances result ed in reduction of overjet , correction of molar relationships , and reduction in severity of malocclusion . Most of this correction was due to dentoalveolar change , but some was due to favorable skeletal change . Early treatment with the Twin-block appliance is effective in reducing overjet and severity of malocclusion . The small change in the skeletal relationship might not be considered clinical ly significant A prospect i ve clinical study with a r and om allocation of 47 adolescent patients to three different functional appliance groups was established and compared with an untreated control group over a 9-month period . Treatment was undertaken with either a Bionator , Twin Block , or Bass appliance . Pre- and post-treatment cephalograms were used to quantify the skeletal and dentoalveolar changes produced by the appliances and compared with those observed in the control group as a result of growth . Both the Bionator and Twin Block appliances demonstrated a statistically significant increase in m and ibular length ( 3.9 + /- 2.7 mm ; 3.7 + /- 2.1 mm , respectively ) compared with the control group ( P < 0.05 ) , with an anterior movement of pogonion and point B. Highly statistically significant increases ( P < 0.01 ) were seen in lower face heights for all the appliance groups compared with the control group . The Twin Block group showed the least forward movement of point A due to a change in the inclination of the maxillary plane . The Bionator and Twin Block groups showed statistically significant reductions in the inclination of the upper incisors to the maxillary plane ( P < 0.05 ) . The Bass group showed minimal change in the inclination of the lower labial segment to the m and ibular plane . The Bionator group demonstrated the greatest proclination of the lower labial segment ( 4.0 + /- 3.6 degrees ) . Clinical ly important changes were measured in all the appliance groups when compared with the control group . Differences were also identified between the functional appliance groups . The Twin Block appliance and , to a lesser extent , the Bionator appeared the most effective in producing sagittal and vertical changes A prospect i ve clinical study with a r and om allocation of 47 patients to three different functional appliance groups was established and compared with a slightly younger control group over a 9-month period . The cephalometric hard tissue changes were assessed in relation to the soft tissue changes produced and the patients were also assessed by three-dimensional ( 3D ) laser scanning of the facial soft tissues . Each ' averaged ' appliance group scan was compared with the ' averaged ' control group face . Statistically and clinical ly significant changes occurred in the group treated with the Twin Block appliance , and to a lesser extent in the group treated with the Bionator appliance . No statistically significant facial soft tissue changes could be demonstrated in the Bass appliance group . Upper lip position remained stable despite the significant overjet reduction attained in the three appliance groups . Lower lip protrusion ( up to 3.8 mm ) , lower lip length ( up to 4.0 mm ) , and soft tissue lower and total face height increased significantly in all appliance groups by varying amounts . The long-term effect of these changes needs to be fully evaluated . The laser scanning system was found to be a sensitive and accurate method of quantitatively assessing small changes in the soft tissue facial form . Significant changes of the facial tissues in the transverse plane were highlighted by this technique INTRODUCTION The purpose of this study was to evaluate the skeletal and dentoalveolar effects of the Twin-block and bionator appliances in the treatment of Class II Division 1 malocclusions . METHODS Fifty-five girls from North India with Class II Division 1 malocclusion and the same physical growth maturation status were selected for the study . The subjects were divided among a Twin-block group ( n = 25 ) , a bionator group ( n = 20 ) , and a control group ( n = 10 ) . Pretreatment and posttreatment lateral cephalometric radiographs of the treatment group subjects , and prefollow-up and postfollow-up radiographs of the control group subjects , were traced manually and subjected to the pitchfork analysis . RESULTS Statistical software was used for 1-way analysis of variance and multiple comparisons ( post-hoc test , Bonferroni ) . A P value of .05 was considered statistically significant . Neither the Twin-block nor the bionator appliance significantly restricted forward growth of the maxilla ( P = .476 ) . M and ibular growth in the Twin-block subjects was significantly greater than in controls ( P = .005 ) . M and ibular growth was comparable in the control and the bionator subjects . Molar correction , overjet reduction , and proclination of the m and ibular incisors were significantly greater ( P = .000 ) in the treated subjects compared with the controls . CONCLUSIONS Both the Twin-block and bionator appliances were effective in correcting molar relationships and reducing overjets in Class II Division 1 malocclusion subjects . However , the Twin-block was more efficient than the bionator in the treatment of Class II Division 1 malocclusion This prospect i ve controlled study investigated the net effects of the Twin Block functional appliance taking into account the effects of normal growth in an untreated control group . The treatment group consisted of 36 subjects , mean age of 12.4 years , consecutively treated with Twin Block appliances for an average period of 0.9 years . Each subject had immediate pre- and posttreatment lateral cephalograms . The control group consisted of 27 subjects with a mean age of 12.1 years . These patients were observed for a mean time of 1.2 years and had radiographic investigation at the initial consultation and immediately before the start of Twin Block therapy . The data were then annualized and subjected to multiple regression analysis . In the treatment group , a reduction in ANB of 2.0 degrees ( p < 0.001 ) was observed largely because of an increase in SNB of 1.9 degrees ( p < 0.001 ) . No statistically significant restraint in the maxillary growth was observed . Treatment result ed in an increase in Ar-Pog of 5.1 mm ( p < 0.001 ) compared with the control group increase in Ar-Pog of 2.7 mm , result ing in a net gain of 2.4 mm . The overjet was reduced by combination of a net maxillary incisor retroclination of 10.8 degrees ( p < 0.001 ) , net m and ibular incisor proclination of 7.9 degrees ( p < 0.001 ) and forward movement of the m and ible . Buccal segment relationships were corrected by means of lower molar eruption , restraint in the eruption of the upper molars and forward growth or repositioning of the m and ible . Any possible fossa adaption was not assessed 
    Output:
    
Clinical ly significant restraint of maxillary growth was not found .
Although the m and ibular body length is increased , the facial impact of it is reduced by the simultaneous increment of the face height .
Changes of lower face height and occlusal plane inclination varied , suggesting that vertical dimension can be manipulated in patients who would benefit from lower molar extrusion .
As for lip position , there is not enough evidence to suggest clear lip position changes .
Changes associated with a Class II correction were identified .
Most of the changes individually were of limited clinical significance , but when combined reached clinical importance .