***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: AIM To assess the prevalence of adjustment for confounding within statistical analysis and matching at the design stage in leading orthodontic journals and to explore potential associations between accounting for confounding and publication characteristics . MATERIAL S AND METHODS Twenty-four issues of four leading orthodontic journals with the highest impact factor were search ed from July 2014 backwards . Confounding adjustment through statistical analysis and study characteristics including journal , study design , region of origin , number of authors , number of centres , involvement of a statistician , significance of results , and type of analysis were recorded . Reporting of matching at the design stage was also recorded . RESULTS Of 426 studies identified , only 71 ( 17 per cent ) accounted for confounding in the statistical analysis . There was evidence that journal , country of authors hip , and involvement of a statistician ( odds ratio = 3.91 , 95 per cent confidence interval : 2.16 - 7.10 ; P < 0.001 ) were significant predictors of accounting for confounding at the analysis level . Reporting of matching at the design stage was identified in 111 of 426 ( 26 per cent ) studies in which 9 studies adjusted for confounding at the analysis level . CONCLUSIONS Appropriate adjustment for confounding in orthodontic literature either at the design or at the analysis stage was identified in less than half of studies overall ( 41 per cent ) , suggesting lack of expertise and awareness in design , conduct , analysis , and reporting of non-r and omized studies in this field . This is a critical limitation that can potentially result in biased estimates and associations between examined exposures and outcomes OBJECTIVES To assess the hypothesis that there is excessive reporting of statistically significant studies published in prosthodontic and implantology journals , which could indicate selective publication . METHODS The last 30 issues of 9 journals in prosthodontics and implant dentistry were h and - search ed for articles with statistical analyses . The percentages of significant and non-significant results were tabulated by parameter of interest . Univariable/multivariable logistic regression analyses were applied to identify possible predictors of reporting statistically significance findings . The results of this study were compared with similar studies in dentistry with r and om-effects meta-analyses . RESULTS From the 2323 included studies 71 % of them reported statistically significant results , with the significant results ranging from 47 % to 86 % . Multivariable modeling identified that geographical area and involvement of statistician were predictors of statistically significant results . Compared to interventional studies , the odds that in vitro and observational studies would report statistically significant results was increased by 1.20 times ( OR : 2.20 , 95 % CI : 1.66 - 2.92 ) and 0.35 times ( OR : 1.35 , 95 % CI : 1.05 - 1.73 ) , respectively . The probability of statistically significant results from r and omized controlled trials was significantly lower compared to various study design s ( difference : 30 % , 95 % CI : 11 - 49 % ) . Likewise the probability of statistically significant results in prosthodontics and implant dentistry was lower compared to other dental specialties , but this result did not reach statistical significant ( P>0.05 ) . CONCLUSIONS The majority of studies identified in the fields of prosthodontics and implant dentistry presented statistically significant results . The same trend existed in publications of other specialties in dentistry Background The extraction rate in orthodontics varies throughout the years . While the extraction decision is easily made or excluded in clear-cut cases , it still remains controversial what makes an orthodontist decide to extract in borderline cases . The aim of this retrospective study was to identify the percentage of extraction cases in a large group of Class I malocclusions and to clarify which variables contributed most to the extraction decision . Methods The sample consisted of 542 r and omly selected records of Class I patients treated in a university graduate program and in five private orthodontic offices . Of these patients , 331 were female and 211 male . The mean age was 14.55 ( st and ard deviation ( SD ) 5.36 ) for the non- extraction group and 14.52 ( SD 4.86 ) for the extraction group . The extensive series of 32 linear and angular measurements derived from the cephalometric analysis and the dental casts , along with the variables of age and gender , fueled a stepwise discriminant analysis . Results The percentage of the patients treated with four first premolar extraction  s was 26.8 % . The results showed that the variables of lower crowding , lower lip to E-plane , upper crowding , and overjet accounted most for the decision to extract at a very significant level ( Sig . 0.000 ) . The discriminant analysis assigned a classification power of 83.9 % to the predictive model ( p < 0.0001 ) . Fisher 's linear discriminant functions provided a mathematical model , according to which any case can be classified into the adequate treatment group . Conclusions In a large contemporary sample of 542 Class I patients , the  extraction rate was 26.8 % . The most important measurements when the orthodontist decides extraction s in Class I cases are lower crowding , lower lip to E-plane , upper crowding , and overjet . In clinical orthodontic practice , the findings facilitate treatment by providing evidence -based treatment predictors for Class I malocclusions OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity INTRODUCTION The purpose of this investigation was to determine the long-term differences in soft tissue profile changes between extraction and non extraction patients who had been treated to the same incisor position and lip line . METHODS Twenty extraction and 20 matched non extraction patients , with posttreatment and long-term follow-up ( average 15 years ) records , were selected from a single private orthodontic practice . Posttreatment and long-term follow-up profile photos of the patients ' nose , lip , and chin areas were evaluated by 105 orthodontists and 225 laypeople , who indicated their preferences and the amount of change they perceived among the 40 profiles . The patients had similar dental protrusion , soft tissue profile measurements , and ages at the posttreatment observation . RESULTS No significant cephalometric differences between the extraction and non extraction groups were found at long-term follow-up ; both groups showed similar long-term changes . Significant ( P < .05 ) differences were found between males and females at long-term follow-up ; male lips became relatively more retrusive , and their profiles became flatter . Significant ( P < .05 ) changes in the profiles were also perceived over time , but there was no relationship between the amount of change perceived and profile changes measured cephalometrically . There were also no significant ( P < .05 ) differences in preferences between orthodontists and laypeople , between extraction and non extraction patients , or between males and females . CONCLUSIONS If extraction and non extraction patients are treated to the same incisor position and lip line , the treatment modality does not affect long-term soft tissue profile changes . Furthermore , the amounts of change perceived by either orthodontists or laypeople were not related to the amount of change measured cephalometrically Non-r and omized studies may provide valuable evidence on the effects of interventions . They are the main source of evidence on the intended effects of some types of interventions and often provide the only evidence about the effects of interventions on long-term outcomes , rare events or adverse effects . Therefore , systematic review s on the effects of interventions may include various types of non-r and omized studies . In this second paper in a series , we address how review authors might articulate the particular non-r and omized study design s they will include and how they might evaluate , in general terms , the extent to which a particular non-r and omized study is at risk of important biases . We offer guidance for describing and classifying different non-r and omized design s based on specific features of the studies in place of using non-informative study design labels . We also suggest criteria to consider when deciding whether to include non-r and omized studies . We conclude that a taxonomy of study design s based on study design features is needed . Review authors need new tools specifically to assess the risk of bias for some non-r and omized design s that involve a different inferential logic compared with parallel group trials . Copyright © 2012 John Wiley & Sons , This investigation was design ed to compare the esthetic effects of extraction and non extraction treatments .  Panels of 58 laypersons and 42 dentists evaluated r and omly presented pre- and posttreatment profiles of 70 extraction and 50 non extraction Class I and II Caucasian patients . The sample s were similar at the outset ; however , at the end of treatment , the extraction patients ' faces were , on average , 1.8 mm " flatter " than the faces of non extraction subjects . The flatter faces were preferred by both panels , dentists more so than laypersons . In general , non extraction treatment was seen as having little effect on the profile , whereas the perceived effect of extraction treatment was a statistically significant function of initial soft tissue protrusion-the greater the initial protrusion , the greater the benefit . The point at which a reduction in protrusion produces a perceived improvement was explored by way of regression analysis . Both panels saw extraction as being potentially beneficial when the lips were more protrusive than 2 to 3 mm behind Ricketts ' E-plane . It is concluded that extraction treatment can produce improved facial esthetics for many patients who present with some combination of crowding and protrusion Obesity is a widespread chronic inflammatory disorder characterized by an increased overall disease burden and significant association with periodontitis . The aim of this prospect i ve clinical cohort study was to investigate the effect of obesity on orthodontic tooth movement . Fifty-five adolescent patients ( 27 males , 28 females ) with a mean ( SD ) age of 15.1 ( 1.7 ) years and mean ( SD ) body mass index ( BMI ) of 30.2 ( 3.5 ) kg/m2 in obese and 19.4 ( 2.2 ) kg/m2 in normal-weight groups were followed from start of treatment to completion of tooth alignment with fixed orthodontic appliances . Primary outcome was time taken to complete tooth alignment , while secondary outcomes included rate of tooth movement and change in clinical parameters ( plaque/gingival indices , unstimulated whole-mouth salivary flow rate , gingival crevicular fluid biomarkers ) . Data collection took place at baseline ( start of treatment : appliance placement ) , 1 h and 1 wk following appliance placement , and completion of alignment . Results were analyzed by descriptive statistics followed by generalized estimating equation regression modeling . There were no significant differences between groups in time taken to achieve tooth alignment ( mean [ SD ] 158.7 [ 75.3 ] d ; P = 0.486 ) . However , at 1 wk , initial tooth displacement was significantly increased in the obese group ( P < 0.001 ) , and after adjusting for confounders , obese patients had a significantly higher rate of tooth movement compared with normal-weight patients ( + 0.017 mm/d ; 95 % confidence interval , 0.008–0.025 ; P < 0.001 ) over the period of alignment . Explorative analyses indicated that levels of the adipokines leptin and resistin , the inflammatory marker myeloperoxidase ( MPO ) , and the cytokine receptor for nuclear factor kappa-B lig and ( RANKL ) were significantly different between obese- and normal-weight patients and associated with observed rates of tooth movement . This represents the first prospect i ve data demonstrating a different response in obese patients compared with normal-weight patients during early orthodontic treatment . These differences in the response of periodontal tissues to orthodontic force in the presence of obesity have potential short- and long-term clinical implication 
    Output:
    
Although tooth extraction s seem to affect patient profile , existing studies are heterogenous and no consistent predictions of profile response can be made