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european journal of orthodontics 33 2011 143­149 doi:10.1093/ejo/cjq045 advance access publication 14 july 2010 © the author 2010 published by oxford university press on behalf of the european orthodontic society all rights reserved for permissions please email journals.permissions@oup.com a systematic review of the interceptive treatment of palatally displaced maxillary canines julia naoumova jüri kurol and heidrun kjellberg department of orthodontics institute of odontology at the sahlgrenska academy university of gothenburg göteborg sweden correspondence to dr julia naoumova institute of odontology at the sahlgrenska academy university of gothenburg box 450 se-405 30 göteborg sweden e-mail julia.naoumova@vgregion.se summarythe aim of this study was to assess whether interceptive treatment in the mixed dentition prevents impaction of palatally displaced canines pdc by systematically reviewing the literature a literature search of pubmed the cochrane library electronic databases and scopus was performed covering the period from january 1966 to may 2009 the inclusion criteria were mixed dentition with unilateral or bilateral pdc randomized controlled trials rct prospective and retrospective studies with untreated controls and clinical trials comparing at least two treatment strategies three reviewers selected and extracted the data independently and evaluated the quality of the studies inter-examiner reliability was measured using the intraclass correlation coefficient icc the search strategy resulted in 686 articles of which two met the inclusion criteria because of the unequivocal results and heterogeneity in the study methods the scientific evidence was too weak to fully evaluate the effect that interceptive treatment might have on pdc and which treatment modalities are most effective the quality of the studies was rated as low because of inadequate sample selection and deficient description of sample size confounding factors uncertainty of randominization and no blinding in measurements the icc value for total scores was >0.80 e.g perfect agreement to obtain reliable scientific evidence as to whether interceptive treatment prevents impaction of pdc and which treatment modalities are the most effective better controlled and well-designed rcts are needed future studies should also include assessment of patient satisfaction and pain experience as well as analysis of the costs and side-effects of treatments downloaded from ejo.oxfordjournals.org at funda o coordena o de aperfei?oamento de pessoal de n?vel superior on june 7 2011 introduction the maxillary canines usually emerge at the mean age of 10.5 years in girls and 11.5 years in boys with individual variation of 3­4 years hägg and taranger 1986 shapira and kuftinec 2001 in 2­3 per cent of the caucasian population these teeth fail to erupt and become impacted which is defined as obstruction by hard or soft tissue structures and/or an ectopic eruption pattern thilander and myrberg 1973 other definitions that are used in literature are ectopic or displaced meaning an abnormal position that may result in tooth impaction hitchin 1956 the aetiology of the impacted canines is obscure and probably multifactorial thilander and myrberg 1973 peck et al 1994 pirinen et al 1996 becker et al 1999 early preventive measures in the mixed dentition for palatal canine impaction are desirable due to the risk of root resorption of the neighbouring permanent incisors such resorptions have been reported to occur in 47 per cent of subject in the age range of 10­13 years ericson and kurol 1987 1988a,b 2000 several studies have been carried out concerning interceptive treatment of palatally displaced canines pdc ericson and kurol 1988a,b power and short 1993 jacobs 1996 bruks and lennartsson 1999 leonardi et al 2004 ngan et al 2005 baccetti et al 2008 however a considerable variation in diagnostic tools study designs sample sizes and research approach has produced results and conclusions that are sometimes conflicting and may be difficult to compare and interpret therefore review articles are beneficial even if many reviews bishara 1992 kuftinec and shapira 1995 rupp 1997 richardson and russell 2000 are well designed they are often biased due to lack of formal methodology and inclusion criteria in view of this and because evidence-based medicine has grown in importance evidence-based medicine group 1992 a systematic review of the present knowledge seems desirable recently a systematic review was published reporting quantitative data on the outcome of the correction of pdc by extracting the primary canine parkin et al 2009 however no previous systematic review has focused on the interceptive treatment of pdc overall without any restrictions on the therapy itself and which treatment is the most effective therefore this systematic review was undertaken to answer the following questions can interceptive treatment in the mixed dentition prevent impaction of pdc which

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144 treatment modality is the most effective regarding total treatment time side-effects and cost how do patients experience subjectively different treatment procedures and pain during treatment materials and methods search strategy the strategy for undertaking this systematic review followed the guidelines from the national health service nhs center for reviews and dissemination 2001 a computerized search was conducted using the medline database entrez pubmed www.ncbi.nlm.nih.gov the cochrane collaboration oral health group database of clinical trials www.cochrane.org and scopus http www scopus.com the search covered the period from january 1966 to may 2009 the terms used in the search were `teeth tooth canine cuspid eyeteeth and eyetooth in various combinations with `impact ectopic eruption abnormalities displace unerupt palatal and retain furthermore a quality analysis of the methodological soundness of the studies included in the review was performed selection criteria the inclusion and exclusion criteria are given in detail in table 1 interceptive treatment was defined as that between the ages of 10­13 years allowing the maxillary pdc to resolve their unfavourable positions to correct their path of active eruption and to erupt spontaneously without further surgical intervention all three authors independently assessed all article abstracts that appeared to meet the inclusion criteria which were collected irrespective of the language in which they were published the full article of the abstracts that met the inclusion criteria were ordered and read in addition the reference lists of the retrieved articles were checked for additional studies any interexaminer conflicts were resolved by discussion to reach a consensus data collection and analysis the following data were collected author year of publication study design definition of pdc materials dropouts measurements treatment time follow-up success rate side-effects costs patient satisfaction and pain experience and author s conclusion to document the methodological soundness of each article a quality evaluation as well as external and internal validity were assessed independently for each study by the three authors the studies were graded with a score of a­c according to pre-determined criteria table 2 interexaminer conflicts regarding an article were resolved by discussion to reach a consensus based on the evaluated table 1 studies j naoumova et al initial inclusion and exclusion criteria for the retrieved inclusion criteria interceptive treatment late mixed dentition with uni or bilateral palatally displaced canine/s randomized clinical trials or prospective retrospective observational studies with concurrent untreated/normal controls examination with radiographs and/or models clinical trials comparing at least two treatment strategies without any untreated or normal control group involved exclusion criteria animal studies case reports and case series and preliminary reports treatment combined with extraction of permanent tooth teeth or full-fixed appliances treatment in the early mixed and permanent dentition adults reviews discussions and interviews previous orthodontic treatment downloaded from ejo.oxfordjournals.org at funda o coordena o de aperfei?oamento de pessoal de n?vel superior on june 7 2011 table 2 criteria for grading of assessed studies grade a high value of evidence all criteria should be met randomized clinical study or a prospective study with a well-defined control group defined diagnosis and endpoints diagnostic reliability tests and reproducibility tests described blinded outcome assessment grade b moderate value of evidence all criteria should be met cohort study or retrospective case series with defined control or reference group defined diagnosis and endpoints diagnostic reliability tests and reproducibility tests described grade c low value of evidence one or more of the conditions below large attrition unclear diagnosis and endpoints poorly defined patient material outcome of treatment patients that are lost during the trial and not included in the analysis table 3 level 1 2 3 4 definitions of evidence level evidence strong moderate limited inconclusive definition at least two studies assessed as level `a one study as level `a and at least two studies as level `b at least two studies a level `b fewer than two studies as level `b studies the final level of evidence for each conclusion was judged according to the protocol of the swedish council on technology assessment in health care sbu 2005 table 3 which is based on the criteria for assessing study quality from the centre for reviews and disseminations in york 2001

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systematic review of pdc 145 studies ethical approval and informed consent were declared baccetti et al 2008 in both studies intraoral radiographs and a dental pantogram dpt were used to diagnose and measure the pdc but none of the studies clarified how they defined a pdc when including the patients in the trial lateral cephalograms were used in both studies but for different aims in one to assess the sagittal position of the upper first molar and in the other to assess the skeletal age before extraction of the primary canine the observation period for the groups was 18 months in both studies in one of the studies all groups were followed-up for an additional 30 months after which successful or unsuccessful canine eruption was assessed leonardi et al 2004 a successful outcome was defined in both studies as a full eruption of the permanent canine the success rate was reported to be between 50 and 65.2 per cent in the extraction group while in the extraction group followed by headgear treatment the success rate was between 80 and 87.5 per cent compared with the control group of 25 and 50 per cent neither of the two studies reported any side-effects nor was a cost analysis performed furthermore neither included information regarding patient satisfaction and/or pain experience quality of the studies the research quality and methodological standard were assessed to have a low value of evidence grade c for both studies leonardi et al 2004 baccetti et al 2008 therefore no evidence-based conclusions could be drawn the most obvious shortcomings were small sample sizes problems of bias and confounding variables lack of selection description and definition of a pdc only one of the studies had a power analysis baccetti et al 2008 but no explanation was given to the underlying assumptions that led to the number therefore the power of the sample in the study was questionable the other study had insufficient sample sizes implying low power with high risk to achieve insignificant outcomes in spite of true differences leonardi et al 2004 furthermore neither study discussed the possibility of a type-ii error occurring the selection description was not adequate due to unclear inclusion exclusion criteria and the absence of a definition of a pdc both studies were stated to have rct design but lacked information regarding the randomization procedure for the groups and how the unilateral and/or bilateral cases were randomized thus the study designs were assessed to be prospective and not rct furthermore the number of patients in each group was not equal which also questions randomization the number of dropouts was given in both studies table 5 but descriptive information regarding the dropouts was missing in addition there was a discrepancy regarding the number of patients in both of the studies after the dropouts one of the studies reported the follow-up statistical analysis inter-examiner reliability was undertaken using the intraclass correlation coefficient icc which is commonly used to measure agreement between two or more reviewers computed icc values range from -1 perfect disagreement to +1 which occurs when assessments are in perfect agreement in this study the included articles were rated by three reviewers therefore a one-way random-effects model for icc calculations was used ratings for icc were <0.20 `slight agreement 0.21­0.40 `fair agreement 0.41­0.60 `moderate agreement 0.61­0.80 `substantial agreement and >0.80 `almost perfect agreement results the search strategy in the medline database resulted in 686 articles after analysis according to the inclusion/exclusion criteria two articles remained for inclusion the reasons for exclusion and the number of excluded articles are listed in table 4 searching the cochrane collaboration oral health group database of clinical trials and scopus or hand searching the reference lists did not result in additional articles other than those included from the medline database therefore only the articles from the medline database are listed in table 4 reliability of the assessments for the quality grades of the included articles the icc value for total scores was >0.80 between the reviewers in assessing the data extraction summarized data of the included studies summarized data of the two studies are shown in table 5 both studies had a randomized controlled trials rct design and the treatment modalities extractions of the primary canines alone or in association with the use of cervical-pull headgear were compared with a control group leonardi et al 2004 baccetti et al 2008 in one of the table 4 distribution of excluded articles no of excluded articles downloaded from ejo.oxfordjournals.org at funda o coordena o de aperfei?oamento de pessoal de n?vel superior on june 7 2011 exclusion criteria studies not concerning the objectives of this review 424 analysis of surgical techniques treatment in the primary or permanent dentition aetiological studies objectives that do not follow this review interceptive treatment without controls prevalence studies diagnostic tools predictions for impaction and complications if treatment is not done animal studies 32 case reports case series and preliminary reports 189 review articles discussions and interviews 39 total 684

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146 table 5 material size gender age years and dropouts observation 18 months assessed after 18 months eg 65.2 ehg 87.5 not declared methods/measurements observation time follow-up time success rate of canine/s erupted summarized published data of the two studies included in this review side-effects/cost outcome/author s patient satisfaction conclusion article study design definition of pdc baccetti et al 2008 prospective not declared controlled clinical trial follow-up not declared cg 36.0 observation 18 months assessed after 48 months extractions resulted in more than twice as successful eruption of pdc compared with cg ehg was almost three times more effective than cg leonardi et al 2004 not declared prospective controlled clinical trial not declared no significant difference between eg and cg eg 50 significant difference between eg and ehg no significant differences between eg and ehg for time required for canine eruption s 75 subjects extraction of primary canine versus extraction of primary five dropouts canine followed by cervicaleg 23 8 boys,15 girls pull headgear versus with 25 pdc non-extraction age mean 11.7 ehg 24 10 boys,14 girls dpt ericson and kurol with 35 pdc 1988a,b age mean 11.9 periapical radiographs double determination cg 22 9 boys,13 girls lateral cephalograms björk with 26 pdc and skieller 1983 age mean 11.6 s 50 subjects extraction of primary canine versus extraction of primary seven dropouts canine followed by cervical-pull headgear versus non-extraction eg 11 5 boys 6 girls dpt ericson and kurol with 14 pdc 1988a,b age mean 11.6 ehg 21 7 boys 14 girls periapical radiographs with 35 pdc age mean 12.2 cg 14 4 boys 10 girls lateral cephalograms baccetti with 26 pdc et al 2002 age mean 11.6 follow-up ehg 80 48 months from start i.e 30 months after the observation cg unequivocal period results 25 and or 50 eg extraction group ehg extraction/headgear group cg control group pdc palatal displaced canine and dpt dental pantogram j naoumova et al downloaded from ejo.oxfordjournals.org at funda o coordena o de aperfei?oamento de pessoal de n?vel superior on june 7 2011

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systematic review of pdc 147 the palatal position and severity of canine displacement it is remarkable that neither study made any comment on this point which could have affected the results moreover precise information of the time when the dpts were taken in both trials was lacking which is useful when evaluating the results and must therefore be considered as a confounding variable the outcome or authors conclusions differed between the two articles concerning interceptive treatment with extraction of a primary canine while extraction of a primary canine followed by treatment with headgear resulted in more successful eruption of the pdc in one of the studies it was not clear if the percentage of successful eruption in the control group was 25 or 50 per cent as different figures were given in different places in the article leonardi et al 2004 therefore it is not clear whether there were any significant differences between the extraction and control group in that study leonardi et al 2004 one reason for these conflicting results could be the disparity of the sample size a sample size calculation required to make the observed differences statistically significant was stated in only one of the studies but did not explain the underlying assumptions that led to the number baccetti et al 2008 furthermore the patients included in both studies were at dental age 8­13 years which can lead to false diagnose of pdc because between 5 and 9 years of age the canines tend to move palatally with substantial movement in a buccal direction between 10 and 12 years mcsherry and richardson 1999 the number of dropouts were reported in both studies with a discrepancy regarding the number of enrolled patients after the dropouts descriptive information and the severity of canine displacement for the dropouts were not presented nor were the results presented with or without the dropouts in the analysis the selection description was inadequate in both studies with some unclear inclusion/exclusion criteria e.g how a pdc was defined when including patients in the trial was not mentioned the authors did not explain why patients with multiple and/or advanced caries or aplasia were excluded even though previous aetiological studies have shown that there is an association between aplasia and pdc thilander and jakobson 1968 peck et al 1994 pirinen et al 1996 becker et al 1999 neither of the studies had information regarding the malocclusion and crowding except that crowding was an exclusion criteria in one of the studies baccetti et al 2008 and an inclusion criteria in the other leonardi et al 2004 in addition it was not reported how crowding was measured and defined and the hypothesis behind using headgear in patients with a pdc was not stated patients were instructed to start using headgear after 3 baccetti et al 2008 and 6 leonardi et al 2004 months after extraction of the primary canine why the patients had to wait for the headgear therapy or if the results were judged from the start of the extraction or from the start of headgear wear was not described furthermore neither of the studies reported the period 48 months with information concerning the average time for complete eruption of the canine which was 20 months leonardi et al 2004 while in the other study an unsuccessful outcome was assessed after 18 months of treatment baccetti et al 2008 the methods used to detect and analyse the treatment effects are well-known ericson and kurol 1988a,b both studies included a method error analysis and used appropriate statistical analysis but the choice of statistical methods was not explained concerning the clustering of patients with bilateral pdc none of the studies used blinding in the measurements discussion the aim of this systematic review was to answer questions on whether interceptive treatment in the mixed dentition prevents impaction of pdc which treatment modality is most effective and patient satisfaction and pain experience during these treatments besides covering randomized and controlled clinical trials which is the scope of the cochrane report parkin et al 2009 the present review also included prospective and retrospective observational studies with concurrent controls as well as observational studies comparing different treatment modalities which should not be ignored when assessing the scientific literature ioannidis et al 2001 to answer the aims of this trial an exhaustive literature search was performed however no evidence-based conclusions could be drawn due to the few studies found and their unequivocal results moreover the included studies had problems with insufficient or lack of sample selection description no discussion of confounding factors lack of blinding in measurements and large differences between the groups at baseline numerous methods and scales to incorporate quality into systematic reviews have been published and have been widely applied to various rcts in medicine colditz et al 1989 jadad et al 1996 however many of the items suggested were clearly not applicable to this systematic review instead the quality of the articles included in this trial was graded as low moderate or high according to the protocol of sbu 2005 table 3 which is based on criteria for assessing study quality from the centre for reviews and disseminations in york 2001 moreover previous studies have reported the importance of using numerous databases when searching and selecting literature for systematic reviews chalmers and altman 1995 suarez-almazor et al 2000 flores-mir et al 2006 therefore more than one database was used to search and identify the articles for this trial the search strategy resulted in 686 articles but after analysis according to the inclusion/exclusion criteria table 1 only two articles remained that qualified for the analysis in both studies the methods to detect and analyse the treatment effects are well-known however two-dimensional radiographs were used and it remains to be evaluated whether this is a reliable method in determining downloaded from ejo.oxfordjournals.org at funda o coordena o de aperfei?oamento de pessoal de n?vel superior on june 7 2011

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148 method for randomization for the groups or how the unilateral and/or bilateral cases were randomized even though the studies were reported to have a rct-design with randomized material the number of patients and pdc in each group differed which questions the study design the severity of canine displacement in the three groups studied was stated to be similar but the results show that inclination of the upper canine to the midline the vertical distance from the occlusal plane and the distance from the midline differed between the three group before treatment which could have influenced the outcome descriptive data on the measurements at the start and end of the trial were not presented in the study of baccetti et al 2008 only comparisons of changes were included in one of the studies the duration of the observation period was ambiguous the follow-up period was reported to be either 18 or 48 months leonardi et al 2004 as the complete eruption of the canine varied widely it would have been favourable to assess the treatment outcome for a longer than 18 months as in the study of baccetti et al 2008 neither of the studies reported the use of blinding in measurement or analysis such studies are more likely to show the advantage an improvement has over a standard treatment method ioannidis et al 2001 it is difficult to use blind assessment in this type of study but for example the extracted tooth and the bands in the headgear-treated group could have been concealed on the radiographs when the outcome of treatment was measured the results of this quality analysis were somewhat disappointing and similar shortcomings of the study results have also been presented in another systematic review parkin et al 2009 systematic reviews have become the cornerstone of evidence-based health care and are our most powerful tool in evaluating therapy and the quality of the trial significantly affects the validity of the inferences the results from this systematic review have highlighted valuable guidelines for future studies and show that there is a need for conducting well-controlled rcts regarding the effectiveness of different treatment strategies and for assessing which treatment is most effective in the case of a pdc in the mixed dentition conclusions no evidence-based conclusions could be drawn due to the few studies identified the heterogeneity in study design and the unequivocal results to obtain reliable scientific evidence better controlled rcts with sufficient sample sizes are needed to determine which treatment is the most effective for treating pdc in the mixed dentition future studies should also include analysis of cost and side-effects of the interventions as well as evaluation of patient satisfaction and pain experience during treatment funding fou västra götaland references j naoumova et al baccetti t franchi l mcnamara j a jr 2002 an improved version of the cervical vertebral maturation cvm method for the assessment of mandibular growth angle orthodontist 72 316­323 baccetti t leonardi m armi p 2008 a randomized clinical study of two interceptive approaches to palatally displaced canines european journal of orthodontics 30 381­385 becker a gillis i shpack n 1999 the etiology of palatal displacement of maxillary canines clinical orthodontics and research 2 62­66 bishara s e 1992 impacted maxillary canines a review american journal of orthodontics and dentofacial orthopedics 101 159­171 björk a skieller v 1983 normal and abnormal growth of the mandible a synthesis of longitudinal cephalometric implant studies over a period of 25 years european journal of orthodontics 5 1­46 bruks a lennartsson b 1999 the palatally displaced maxillary canine a retrospective comparison between an interceptive and a corrective treatment group swedish dental journal 23 149­161 centre for reviews and disseminations crd in york 2001 undertaking systematic reviews of research and effectiveness crd s guidance for those carrying out or commissioning reviews crd report no 4 2nd edn publishing services york chalmers i altman d 1995 systematic reviews british medical journal publishing group ltd london colditz g a miller j n mosteller f 1989 how study design affects outcomes in comparisons of therapy i medical statistics in medicine 8 411­454 ericson s kurol j 1987 radiographic examination of ectopically erupting maxillary canines american journal of orthodontics and dentofacial orthopedics 91 483­492 ericson s kurol j 1988a resorption of maxillary lateral incisors caused by ectopic eruption of the canines a clinical and radiographic analysis of predisposing factors american journal of orthodontics and dentofacial orthopedics 94 503­513 ericson s kurol j 1988b early treatment of palatally erupting maxillarycanines by extraction of primary canines european journal of orthodontics 10 283­295 ericson s kurol j 2000 resorption of incisors after ectopic eruption of maxillary canines a ct study angle orthodontist 70 415­423 evidence-based medicine group 1992 evidence-based medicine a new approach to teaching the practice of medicine the journal of the american medical association 268 2420­2425 flores-mir c major m p major p w 2006 search and selection methodology of systematic reviews in orthodontics 2000­2004 american journal of orthodontics and dentofacial orthopedics 130 214­217 hägg u taranger j 1986 timing of tooth emergence a prospective longitudinal study of swedish urban children from birth to 18 years swedish dental journal 10 195­206 hitchin a d 1956 the impacted maxillary canine british dental journal 100 1­14 ioannidis j p a et al 2001 comparison of evidence of treatment effects in randomized and nonrandomized studies the journal of the american medical association 286 821­830 jacobs s g 1996 the impacted maxillary canine further observations on aetiology radiographic localization prevention/interception of impaction and when to suspect impaction australian dental journal 41 310­316 jadad a r et al 1996 assessing the quality of reports of randomized clinical trials is blinding necessary controlled clinical trials 17 1­12 kuftinec m m shapira y 1995 the impacted maxillary canine i review of concepts asdc journal of dentistry for children 62 317­324 leonardi m armi p franchi l baccetti t 2004 two interceptive approaches to palatally displaced canines a prospective longitudinal study angle orthodontist 74 581­586 downloaded from ejo.oxfordjournals.org at funda o coordena o de aperfei?oamento de pessoal de n?vel superior on june 7 2011

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systematic review of pdc 149 richardson g russell k a 2000 a review of impacted permanent maxillary cuspids diagnosis and prevention journal canadian dental association 66 497­501 rupp r 1997 orthodontic management of impacted maxillary cuspids journal of general orthodontics 8 16­20 sbu 2005 bettavvikelser och tandreglering i ett hälsoperspektiv en systematisk litteraturöversikt rapport nr 176 statens beredning för medicinsk utvärdering stockholm shapira y kuftinec m m 2001 maxillary tooth transpositions characteristic features and accompanying dental anomalies american journal of orthodontics and dentofacial orthopedics 119 127­134 suarez-almazor m belseck e homik j dorgan m remus-ramos c 2000 identifying clinical trials in the medical literature with electronic databases medline alone is not enough controlled clinical trials 21 476­487 thilander b jakobson s o 1968 local factors in impaction of maxillary canines acta odontologica scandinavica 26 145­168 thilander b myrberg n 1973 the prevalence of malocclusion in swedish school children scandinavian journal of dental research 81 12­20 mcsherry p richardson a 1999 ectopic eruption of maxillary canine quantified in three dimensions on cephalometric radiographs between the ages of 5 and 15 years european journal of orthodontics 21 41­48 national health service nhs centre for reviews and dissemination 2001 undertaking systematic reviews of research on effectiveness report no 4 2nd edn publishing services university of york york ngan p hornbrook r weaver b 2005 early timely management of ectopically erupting maxillary canines seminars in orthodontics 11 152­163 parkin n et al 2009 extraction of primary baby teeth for unerupted palatally displaced permanent canine teeth in children cochrane database systematic review 15 cd004621 peck s peck l kataja m 1994 the palatally displaced canine as a dental anomaly of genetic origin angle orthodontist 64 249­256 pirinen s arte s apajalahti s 1996 palatal displacement of canine is genetic and related to congenital abscence of teeth journal of dental research 75 1742­1746 power s m short m b 1993 an investigation into the response of palatally displaced canines to the removal of deciduous canines and an assessment of factors contributing to favourable eruption british journal of orthodontics 20 215­223 downloaded from ejo.oxfordjournals.org at funda o coordena o de aperfei?oamento de pessoal de n?vel superior on june 7 2011

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