Influence of Coronal Preflaring on the Accuracy of Electronic Working Length Determination: Systematic Review and Meta-Analysis

Jou nal o Clinical Medicine Re iew In luence o Co onal P e la ing on he Accu acy o Elec onic Wo king Leng h De e mina ion: Sys ema ic Re iew and Me a-Analysis Ma ía León-López, Daniel Cabanillas-Balse a * , Vic o ia A eal-Quecu y, Jeni e Ma ín-González, Ma ía C. Jiménez-Sánchez, Juan J. Saúco-Má quez, Beni o Sánchez-Domínguez and Juan J. Segu a-Egea *   Ci a ion: León-López, M.; Cabanillas-Balse a, D.; A eal-Quecu y, V.; Ma ín-González, J.; Jiménez-Sánchez, M.C.; Saúco-Má quez, J.J.; Sánchez-Domínguez, B.; Segu a-Egea, J.J. In luence o Co onal P e la ing on he Accu acy o Elec onic Wo king Leng h De e mina ion: Sys ema ic Re iew and Me a-Analysis. J. Clin. Med. 2021,10, 2760. h ps:// doi.o g/10.3390/jcm10132760 Academic Edi o : Fede ico Foschi Recei ed: 24 May 2021 Accep ed: 21 June 2021 Published: 23 June 2021 Publishe ’s No e: MDPI s ays neu al wi h ega d o ju isdic ional claims in published maps and ins i u ional a il- ia ions. Copy igh : © 2021 by he au ho s. Licensee MDPI, Basel, Swi ze land. This a icle is an open access a icle dis ibu ed unde he e ms and condi ions o he C ea i e Commons A ibu ion (CC BY) license (h ps:// c ea i ecommons.o g/licenses/by/ 4.0/). Endodon ic Sec ion, Depa men o S oma ology, Uni e si y o Se illa, C/A icena s/n, 41009 Se illa, Spain; [email p o ec ed] (M.L.-L.); ic o ia.a eal@cabime .es (V.A.-Q.); [email p o ec ed] (J.M.-G.); [email p o ec ed] (M.C.J.-S.); [email p o ec ed] (J.J.S.-M.); [email p o ec ed] (B.S.-D.) *Co espondence: [email p o ec ed] (D.C.-B.); [email p o ec ed] (J.J.S.-E.); Tel.: +34-954-481-146 (J.J.S.-E.) Abs ac : Aim. To conduc a sys ema ic e iew and me a-analysis acco ding o he ollowing PICO ques ion: in ex ac ed human pe manen ee h, does p e la ing, compa ed wi h un la ed canals, in luence he accu acy o WL de e mina ion wi h EAL? Ma e ial and Me hods. A sys ema ic e iew was conduc ed acco ding o he PRISMA checklis , using he ollowing da abases: PubMed, Science Di ec , Scopus, and Web o Science. S udies ela ed o WL de e mina ion using EAL bo h in p e la ed and un la ed oo canals o ex ac ed human ee h we e included. The ou come o in e es was he accu acy o he elec onic WL de e mina ion. A quali y assessmen o he included s udies was pe o med, de e mining he isk o bias. The me a-analyses we e calcula ed wi h he 5.4 Re Man so wa e using he in e se a iance me hod wi h andom e ec s. PROSPERO egis a ion: CRD42021243412. Resul s. Ten expe imen al s udies ul illed he inclusion c i e ia, and mos o hem ound ha p e la ing inc eases he accu acy o he EALs in WL de e mina ion. The calcula ed OR was 1.98 (95% CI = 1.65–2.37; p< 0.00001; I 2 = 10%), indica ing ha he de e mina ion o WL by EALs is almos wice as accu a e in p e la ed canals. The accu acy o Roo ZX in WL de e mina ion inc eases mo e han h ee imes (OR = 3.25; p< 0.00001). P e la ing wi h P o ape iles signi ican ly inc eases he accu acy o EALs (OR = 1.76; p< 0.00001). The o al isk o bias o he included s udies was low. No ob ious publica ion bias was obse ed. Conclusions. The esul s indica e a signi ican inc ease in he accu acy o WL de e mina ion wi h EAL a e p e la ing, doubling he pe cen age o exac measu emen s. P e la ing should be ecommended as an impo an s ep du ing mechanical enla gemen o he oo canal, no only because i imp o es he access o he iles o he canal, bu also because i allows one o ob ain mo e accu a e elec onic de e mina ions o WL. Keywo ds: ce ical p e la ing; co onal p e la ing; elec onic apex loca o ; p e la ing; oo canal ea men ; wo king leng h 1. In oduc ion Ini ial passi e explo a ion and scou ing o he oo canal using small s ainless-s eel K- iles sizes, 06 o 10, in a wa ch-winding mo ion enables app ecia ion o he canal’s mo phology and he p esence o pa ency and po en ial esis ance o ile pene a ion [ 1 ]. The e o e, explo a ion and scou ing should be he i s s ep in oo canal shaping. A e ini ial explo a ion and scou ing, a smoo h adicula unnel should be p epa ed om he canal o i ice o he physiologic e minus (apical cons ic ion), wi h his unnel e med as he glide pa h [2]. Howe e , o ensu e ha engine-d i en iles a e used sa ely [3], nego ia ion and he glide pa h may be insu icien . A hi d ope a i e s ep, known as p e la ing, in bo h co onal and apical egions, is also necessa y [ 4 ]. Apical p e la ing has been de ined as a p e-enla gemen o he oo canal up o i s e minus using hand iles o a size a leas equal o he i s engine-d i en shaping ileins umen ha will be used [ 3 ]. Howe e , o educe J. Clin. Med. 2021,10, 2760. h ps://doi.o g/10.3390/jcm10132760 h ps://www.mdpi.com/jou nal/jcm J. Clin. Med. 2021,10, 2760 2 o 15 he isk o o a y ile sepa a ion when engaging in he oo canal, i is also necessa y o p e- enla ge he co onal hi d o he canal [ 5 ]. This ope a ing s ep is called co onal p e la ing [ 6 ]. Co onal p e la ing educes he con ac be ween he ile and he den in walls, minimizing he o sional s ess on he ile. Mo eo e , co onal p e la ing diminishes he ini ial co onal cu a u e, acili a ing he access o he middle and apical hi ds o he canal [ 4 ], and allows, om he s a o he ea men , be e pene a ion o he i igan solu ion owa ds he apical hi d [6]. On he o he hand, exac de e mina ion o he wo king leng h (WL) is a pa amoun ac o bo h o he co ec ins umen a ion and o ob u a ion o he canal, and o he long- e m success o oo canal ea men [ 7 ]. The use o elec onic apex loca o s (EALs) as an aid o de e mine he WL may pe o m be e han adiog aphy alone [ 8 ]. The WL de e mined by EAL dec eases as a esul o canal p epa a ion [ 9 ]. Some s udies ha e shown ha one o he ope a i e s eps a ec ing WL is co onal p e la ing [ 4 , 9 – 11 ]. Howe e , De Moo e al. (1999) ound ha co onal p e la ing did no ensu e be e o mo e p ecise WL eadings [ 10 ]. On he con a y, Dean Da is e al. (2002) epo ed ha , when ini ial WL was de e mined a e co onal p e la ing, ew changes in he inal WL we e obse ed [ 9 ]. In summa y, i is no clea o wha ex en p e la ing in luences he accu acy o inal wo king leng h de e mina ion wi h elec onic apex loca o s. The aim o his s udy was o conduc a sys ema ic e iew and me a-analysis acco ding o he ollowing PICO ques ion: in ex ac ed human pe manen ee h (P), does co onal p e la ing (I), compa ed wi h un la ed canals (C), in luence he accu acy o inal WL de e mina ion wi h EAL (O)? 2. Ma e ials and Me hods This sys ema ic e iew is epo ed using he PRISMA guidelines [ 12 ] and he PICO amewo k. The e iew was egis e ed in PROSPERO (CRD42021243412). 2.1. Li e a u e Sea ch S a egy The sea ch p ocess was pe o med independen ly by ou examine s (M.L.-L., D.C.-B., J.J.S.-M., and J.J.S.-E.). The elec onic da abases PubMed, Scopus, Dialne , and Scielo we e sea ched o a icles published un il 28 Feb ua y 2021, wi hou language, yea es ic ions o limi s. Mos ci ed desc ip o s in he p e ious publica ion on his heme we e used in he elec onic sea ch s a egy, using combining Medical Subjec Heading (MeSH) e ms and ex wo d ( w). Fo each da abase, he ollowing e ms combina ions we e sea ched: (p e la ing OR pe ice ical OR ce ical enla gemen ) AND ( oo canal OR ins umen a ion OR cleaning and shaping OR endodon ic ea men OR oo - illed ee h OR oo - illing OR ob u a ion) AND (den in OR den ine OR wo king leng h OR apical cons ic ion). A complemen a y sc eening o he e e ences o he selec ed s udies was pe o med o ind any addi ional s udy ha did no appea in he p ima y da abase sea ch. 2.2. Eligibili y C i e ia S udies ha e alua ed he accu acy o WL de e mina ion using EAL bo h in p e la ed and un la ed oo canals o ex ac ed human ee h we e included. The eligibili y c i e ia we e based on he PICOS s a egy [13] (PRISMA-P 2016), as ollows: •Popula ion (P): ex ac ed human pe manen ee h; •In e en ion (I): co onal p e la ing o oo canals; •Compa ison (C): un la ed oo -canals; •Ou come (O): accu acy o WL de e mina ion using EAL; •S udy design (S): labo a o y. The ollowing we e excluded: e iews, le e s, opinion a icles, con e ence abs ac s, s udies pe o med in animals, s udies pe o med in humans, s udies ha included a i icial ee h and s udies in which i was no possible o calcula e and compa e he accu acy o WL de e mina ion wi h EAL in p e la ed and un la ed canals. J. Clin. Med. 2021,10, 2760 3 o 15 2.3. S udy Selec ion Fou au ho s (M.L.-L., D.C.-B., J.J.S.-M., and J.J.S.-E.) independen ly selec ed he e ie ed s udies by examining he i les and abs ac s. When he i le and abs ac did no allow o judge he s udy, he ull ex was accessed. A second s age consis ed o eading he ull ex s and judging he po en ial s udies o be included based on he eligibili y c i e ia h ough he PICOS s a egy. Disag eemen s on s udy inclusion we e sol ed by consensus wi h a i h au ho (J.M.-G.). Duplica ed s udies in he da abase sea ch we e conside ed only once. 2.4. Da a Collec ion/Ex ac ion P ocess Fou au ho s (M.L.-L., D.C.-B., J.J.S.-M., and J.J.S.-E.) collec ed he da a independen ly om he included s udies. A i h au ho (J.M.-G.) sol ed disag eemen s. In o ma ion ega ding publica ion (au ho and publica ion yea ), s udy ype, ex ac ed ee h ype, iles used in co onal p e la ing, he ype o EAL used in he de e mina ion o WL, he e e ence o WL accu acy, pe cen ages o accu acy in p e la ed and un la ed canals, and he main esul was ex ac ed. 2.5. Quali y Assessmen and Risk o Bias o Indi idual S udies Each selec ed s udy was e alua ed o inne me hodological isk o bias independen ly by ou au ho s (M.L.-L., D.C.-B., B.S.-D., and J.J.S.-E.). Taking in o accoun he ac ha all included s udies we e “ex i o” labo a o y s udies, a quali y assessmen was adop ed ollowing SYRCLE [ 14 ] wi h adap a ions used in p e ious sys ema ic e iews [15,16] . The ollowing pa ame e s we e conside ed: (i) sample size calcula ion, (ii) samples wi h simila dimensions, (iii) con ol g oup, (i ) s anda diza ion o co onal p e la ing, ( ) s anda diza- ion o EAL accu acy assessmen o WL de e mina ion, and ( i) s a is ical analysis. The blinding o he ope a o was no aken in o accoun , since he EAL ype, ile ype and canals (un la ed and p e la ed) a e e y di e en and allow he ope a o o iden i y he pe o med ea men . The pa ame e s epo ed in o iginal s udies we e sco ed dicho omously as (+) i p esen and ( − ) i missing. Du ing he quali y assessmen , disag eemen s be ween au ho s we e esol ed h ough discussion wi h a i h au ho (M.C.J.-S.). To assess he indi idual isk o bias, he a icles we e classi ied as ha ing a low isk o bias i i e o six i ems we e epo ed, a mode a e isk o bias i h ee o ou i ems we e epo ed, and a high isk o bias i only one o wo pa ame e s we e epo ed. To assess he o al isk o bias, he pe cen age o s udies epo ing each pa ame e was calcula ed, as well as he o al pe cen age o he analyzed pa ame e s ha we e epo ed in all he s udies. 2.6. Ou come o In e es The ou come o in e es was he accu acy o he elec onic wo king leng h de e mina- ion in bo h un la ed and p e la ed canals. The ou come was dicho omized acco ding o whe he he co onal p e la ing signi ican ly in luenced he accu acy o WL de e mina ion, assessed elec onically, o no . The odds a io was calcula ed as a ela i e e ec measu e. 2.7. Da a Syn hesis and S a is ical Analysis The p ima y ou come measu e was he accu acy o WL de e mina ion using EAL. The odds a io (OR), wi h i s 95% con idence in e al (CI), was calcula ed in e e y selec ed s udy o measu e he e ec o p e la ing on WL de e mina ion using EAL. The me a-analysis was ca ied ou on s udies ha p o ided da a, o whe e i was possible o calcula e da a, on he pe cen ages o accu acy in WL de e mina ion wi h EAL in un la ed and p e la ed canals. In some o he included s udies, accu acy was calcula ed as he pe cen age o exac ma ches wi h he apical cons ic ion, while in o he s, a ma gin o ± 0.5 mm was allowed. S udies ha compa ed he accu acy o elec onic WL de e mina ion bu only epo ed da a on means and s anda d de ia ions, no allowing accu acy calcula ion, we e excluded. J. Clin. Med. 2021,10, 2760 4 o 15 Two subg oup analyses we e pe o med, one including he s udies using P o ape iles (Den sply Maille e , Ballaigues, Swi ze land) o p e la ing, and ano he g ouping all s udies using he Roo ZX (J Mo i a Co p, Tokyo, Japan) apex loca o o WL de e mina ion. The me a-analyses we e calcula ed wi h he 5.4 Re Man so wa e (Re iew Manage Web. The Coch ane Collabo a ion, 2019. A ailable a e man.coch ane.o g, accessed on 24 May 2021). The s udies did no conduc he assays using he same me hodology—on he con a y, di e en ypes o p e la ing iles and EALs we e used. The in e se a iance me hod wi h andom e ec s was hus pe o med o de e mine he pooled OR and i s 95% CI. Me a-analyses we e ep esen ed wi h a o es plo [17]. To es ima e he a iance and he e ogenei y amongs ials, he Tau 2 and he Higgins I 2 es s we e employed, conside ing a sligh he e ogenei y i he alue was be ween 25 and 50%, mode a e be ween 50% and 75%, and high i >75% [ 18 ]. The exis ence o s a is ical signi icance was assessed using he Z es (p- alue < 0.05). A unnel plo was plo ed o illus a e he possible exis ence o publica ion bias [19]. 3. Resul s 3.1. Selec ion o he S udies The low diag am o he sea ch s a egy is shown in Figu e 1. The ini ial sea ch esul ed in 96 published s udies om di e en da abases, oge he wi h 8 addi ional s udies iden i ied h ough o he sou ces. Nine s udies we e excluded as hey we e duplica es. Then, om 95 eligible pape s, he analysis o i les and abs ac s esul ed in he inclusion o 16 s udies o in e es . The eason o he ejec ion o 79 a icles was ha hey did no ma ch he inclusion c i e ia, as hey did no ela e co onal p e la ing wi h he EAL accu acy in he de e mina ion o he wo king leng h. A e comp ehensi e eading, 10 ull- ex a icles we e selec ed o he sys ema ic e iew and me a-analysis [ 20 – 29 ], and 6 a icles we e excluded o di e en easons [10,30–34] (Table 1). Table 1. Excluded s udies and he espec i e easons o each exclusion. Reasons o Exclusion Au ho s and Yea Accu acy was no epo ed/canno be de e mined De Moo e al. 1999 [10] Tinaz e al. 2002 [30] Su yan o o e al. 2017 [33] Maniglia-Fe ei a e al. 2017 [34] EAL no used Iqbal e al. 2013 [31] Kuma e al. 2013 [32] 3.2. Cha ac e is ics o he Included S udies The da a collec ed om he en included s udies a e summa ized in Table 2. All he included s udies compa ed he accu acy o di e en EALs in WL de e mina ion in un la ed and p e la ed ee h. Se en s udies used Roo ZX [ 20 , 21 , 23 , 25 , 26 , 28 , 29 ]. The mos used ins umen s o p e la ing we e P o ape SX and S1 iles [ 21 , 23 , 25 , 27 , 28 ], ollowed by LA Axxess bu s (Syb onEndo, Glendo a, CA, USA) [ 22 , 25 ]. All he included s udies used simila me hodologies when p epa ing co onal p e la ed and un la ed ee h and du ing WL de e mina ion wi h EALs. Howe e , some s udies conside ed he measu emen s o WL ha exac ly coincided wi h he apical cons ic ion as accu a e [ 20 , 21 , 23 , 24 , 26 ], and o he s ook he measu emen s ± 0.5 mm om apical cons ic ion as accu a e [ 22 , 25 , 27 – 29 ]. The included s udies used di e en ypes o ee h: inciso s and canines [ 21 , 22 , 25 , 27 , 28 ], p emola s [28], and mola s [20,23,24,29]. Mos o he s udies ound ha p e la ing inc eased he accu acy o he EALs, al- hough he di e ences be ween he accu acy in un la ed and p e la ed canals we e no always signi ican . J. Clin. Med. 2021,10, 2760 5 o 15 3.3. Ou comes o he P ima y Me a-Analysis and Publica ion Bias To ca y ou he me a-analysis, he esul s o he included s udies we e di ided in o sec ions acco ding o he numbe o EALs used and he ype o iles wi h which he p e la ing was ca ied ou . In o al, 34 esul s we e included in he me a-analysis, including 2890 elec onic de e mina ions o wo king leng h, hal in un la ed canals and he o he hal in p e la ed canals. The es ima ed a iance among all esul s was examined by he Tau 2 es , wi h he esul being no signi ican (Tau 2 = 0.03; chi 2 = 36.5; d = 33; p= 0.31). The he e ogenei y es alue (I 2 = 10%) was low; howe e he weigh s we e calcula ed using he andom e ec s model, conside ing ha he e was a ia ion among he included s udies and allowing he s udy ou comes o a y in a no mal dis ibu ion. O e all OR was 1.98 (95% CI = 1.65–2.37; p< 0.00001), indica ing ha he de e mina ion o WL by EALs was signi ican ly mo e accu a e in p e la ed canals compa ed o un la ed canals. The ORs o he 34 esul s o he en included s udies and he pooled OR om he me a-analysis a e shown in a o es plo (Figu e 2). Figu e 1. Flow diag am o he sea ch s egy o he sys ema ic e iew and me a-analysis ollowing he P e e ed Repo ing I ems o Sys ema ic Re iews and Me aanalyses (PRISMA) guidelines. J. Clin. Med. 2021,10, 2760 6 o 15 Table 2. Summa y o desc ip i e cha ac e is ics o included s udies. Au ho s Yea Ex ac ed Tee h Used Files Used in P e la ing EAL Used o WL Re e ence o WL Accu acy Accu acy in Un la ed Canals (%) Accu acy in P e la ed Canals (%) Main Resul Iba ola e al. 1999 16 lowe mola s; 32 mesial canals (Weine III) P o ile 04 sizes 9 o 6 Roo -ZX Exac apical cons ic ion RZX—18.8% RZX—43.8% P e la ing signi ican ly inc eased he accu acy o he WL de e mina ion wi h EAL (p= 0.015). Cama go e al. 2009 40 lowe inciso s (Ve ucci I) P o ape SX P o ape S1 Roo -ZX Edual Mini Apex DSP Exac apical cons ic ion RZX—50% EduaL—47.5% Mini Apex—50% Apex DSP—45% RZX—75% Edual—55% Mini Apex—75% Apex DSP—60% P e la ing signi ican ly inc eased he p ecision o de e mine he eal WL wi h Roo ZX and Mini Apex (p> 0.05), bu no signi ican di e ence was no ed o Edual and Apex DSP (p> 0.05). Mo gen al e al. 2011 30 lowe inciso s LA Axxess 20/0.06 No apex Mini Apex P oPex II ±0.5 mm om apical cons ic ion No apex— 90% Mini Apex—87% P opex II—83% No apex— 100% Mini Apex—100% P opex II—90% P e la ing inc eased he accu acy o Mini Apex and P opex II (p< 0.05), bu no signi ican di e ence was no ed o No apex (p> 0.05). B i o-Junio e al. 2012 24 uppe mola s P o ape SX P o ape S1 No apex Exac apical cons ic ion #10–75% #15–70% #20–80% #10–80% #15–60% #20–70% Co onal p e la ing did no inc ease accu acy in he elec onic measu emen s (p> 0.05). B i o-Junio e al. 2012 24 uppe mola s P o ape SX P o ape S1 Roo -ZX Exac apical cons ic ion #10–65% #15–50% #20–70% #10–80% #15–80% #20–80% Co onal p e la ing signi ican ly inc eased accu acy in he elec onic measu emen s (p< 0.05). Teixei a e al. 2012 25 lowe mola s; 50 canals Ga es-Glidden 4-3-2 Bingo1020 Exac apical cons ic ion Bingo1020— 21% Bingo1020— 25% P e la ing wi h Ga es Glidden d ills we e no able o signi ican ly in luence he accu acy o he apex loca o in de e mining he exac wo king leng h (p> 0.05). J. Clin. Med. 2021,10, 2760 7 o 15 Table 2. Con . Au ho s Yea Ex ac ed Tee h Used Files Used in P e la ing EAL Used o WL Re e ence o WL Accu acy Accu acy in Un la ed Canals (%) Accu acy in P e la ed Canals (%) Main Resul Guima aes e al. 2016 15 lowe inciso s (Ve ucci I) P o ape SX P o ape S1 Joypex 5 RZX Mini ±0.5 mm om apical cons ic ion Joypex 5—80% RZX Mini—80% Joypex 5—100% RZX Mini—100% Bo h EALs p esen ed a highe pe cen age o exac measu emen s a e p e la ing, bu di e ences we e no signi ican (p> 0.05). Guima aes e al. 2016 15 lowe inciso s (Ve ucci I) LA Axxess 20/0.06 Joypex 5 RZX Mini ±0.5 mm om apical cons ic ion Joypex—46.6% RZX Mini—60% Joypex—93.3% RZX Mini—86.6% Ce ical p epa a ion wi h LA-Axxes inc eased he accu acy o he EAL Joypex (p = 0.01), bu no o he RZX Mini (p> 0.05). Vasconcelos e al. 2016 26 lowe mola s (Ve ucci IV); 52 canals Wa eOne P ima y Roo ZX II Exac apical cons ic ion Roo ZX II—7.7% Roo ZX II—15.4% The accu acy o Roo ZX II p esen ed no change conside ing he ime in e al when he elec onic measu emen was made. (p> 0.05) Fe ei a e al. 2019 40 uppe an e io ee h (Ve ucci I). P o ape SX P opex Pixi ±0.5 mm om apical cons ic ion SS iles 10 mm—41.7% 15 mm—39.1% 20 mm—45.9% SS iles 10 mm—53.4% 15 mm—58.3% 20 mm—60.8% P e la ing p ocedu es inc ease he accu acy o P opex Pixi ega dless o he size o he SS ile (p< 0.05). Fe ei a e al. 2019 40 uppe an e io ee h (Ve ucci I). P o ape SX P opex Pixi ±0.5 mm om apical cons ic ion NiTi iles 10 mm—45% 15 mm—45% 20 mm—49.2% NiTi iles 10 mm—60% 15 mm—50.8% 20 mm—57.5% P e la ing p ocedu es inc ease he accu acy o P opex Pixi ega dless o he size o he NiTi ile (p< 0.05). Ja anma di e al. 2020 47 ee h (11 inciso s, 10 canines and 26 p emola s); 60 canals in o al P o ape SX Roo ZX II ±0.5 mm om apical cons ic ion Roo ZX— 63.3% Roo ZX—93.3% P e la ing inc eases he accu acy o RZX in he de e mina ion o WL (p< 0.001). J. Clin. Med. 2021,10, 2760 8 o 15 Table 2. Con . Au ho s Yea Ex ac ed Tee h Used Files Used in P e la ing EAL Used o WL Re e ence o WL Accu acy Accu acy in Un la ed Canals (%) Accu acy in P e la ed Canals (%) Main Resul Ja anma di e al. 2020 47 ee h (11 inciso s, 10 canines and 26 p emola s); 60 canals P o ape SX Mini Apex Loca o ±0.5 mm om apical cons ic ion Mini Apex—90% Mini Apex—96.6% P e la ing does no inc ease he accu acy o Mini Apex in he de e mina ion o WL (p= 0.293). Melo e al. 2020 20 lowe mola s (Ve ucci IV) P odesign Logic 25/0.06 Roo ZX II Raypex 6 RomiApex A-15 ±0.5 mm om apical cons ic ion Roo ZX—20% Raypex 6—25% RomiApex— 25% Roo ZX—40% Raypex 6—42.5% RomiApex— 50% An imp o emen in he accu acy o EALs a e con en ional co onal p e la ing enla gemen was obse ed (p< 0.05). Melo e al. 2020 20 lowe mola s (Ve ucci IV) HyFlex EDM 25/0.12 Roo ZX II Raypex 6 RomiApex ±0.5 mm om apical cons ic ion Roo ZX II—20% Raypex 6—25% RomiApex— 25% Roo ZX II—55% Raypex 6—57.5% RomiApex— 70% An imp o emen in he accu acy o EALs a e con en ional co onal p e la ing enla gemen was obse ed (p< 0.05) P o ile, P o ape and Wa e One (Den sply Maille e , Ballaigues, Swi ze land). LA Axxess (Syb onEndo, Glendo a, CA, USA). P odesign (P odesign Logic; Bassi Endo P oduc , Belo Ho izon e, MG, B azil). Hy lex EDM (Col ene-Whaleden , Alls ä en, Swi ze land). Roo ZX (RZX) and Roo ZX Mini (J Mo i a Co p, Tokyo, Japan). P opex II and P opex Pixi (Den sply Maille e , Ballaigues, Swi ze land) Raypex 6 (VDW GmbH, Munich, Ge many). RomiApex A-15 (Romidan L d., Ki ya Ono, Is ael). Mini Apex Loca o (Syb onEndo, Anaheim, CA, USA). (Denjoy, Changsha, China). Bingo 1020 (Fo um Enginee ing Technologies, RishonLezion, Is ael). Edual (Syb on Den al, Syb on Den al, Anaheim, CA, USA). Apex DSP (Sep odon , Sain -Mau des Fosse’s, Cedex, F ance. No apex (Fo um Technologies, Rishon Le-Zion, Is ael). Figu e 2. Fo es plo o ORs and 95% con idence limi s (CL) o he compa ison o un la ed and p e la ed canals ega ding he accu acy o elec onic apex loca o s (EALs) in wo king leng h (WL) de e mina ion. The o e all es ima e is based on he da a om he en included s udies. Black squa es ep esen he poin es ima e o he odds a io and ha e a eas p opo ional o s udy size. Lines ep esen 95% con idence in e als. The diamond shows he summa y s a is ic o he 34 esul s om he en included s udies. The solid line indica es an odds a io o 1.0. OR: odds a io. J. Clin. Med. 2021,10, 2760 9 o 15 Figu e 3shows a unnel plo o he eligible s udies. The eligible a icles a e dis ibu ed e enly a ound he e ical line ha indica es he summa y es ima e, and s udies wi h highe powe and lowe s anda d e o a e plo ed owa ds he op and low powe ed s udies a e placed nea he bo om. No ob ious publica ion bias was obse ed. Figu e 3. Funnel plo . Each do indica es one o he 34 esul s om he en included s udies. The y axis ep esen s he s anda d e o (SE) o he OR, and he x-axis ep esen s he OR calcula ed in he me a-analysis. 3.4. Addi ional Analysis Conside ing ha Roo ZX was he mos used EAL in he included s udies, a me a- analysis using he in e se a iance wi h he andom e ec s model was ca ied ou including only he esul s o he Roo ZX [ 20 , 21 , 23 , 25 , 26 , 28 , 29 ]. The esul o he Tau 2 es was no signi ican (p= 0.89), wi h 0% he e ogenei y. Calcula ed o e all OR was 3.25 (95% CI = 2.13–4.97 ;p< 0.00001), indica ing ha he accu acy o Roo ZX o WL de e mina ion inc eases signi ican ly, mo e han h ee imes, in p e la ed canals (Figu e 4). Figu e 4. Fo es plo o ORs and 95% con idence limi s (CL) o he compa ison o un la ed and p e la ed canals ega ding he accu acy o Roo ZX in wo king leng h (WL) de e mina ion. The o e all es ima e is based on he da a om he se en included s udies. Black squa es ep esen he poin es ima e o he odds a io and ha e a eas p opo ional o s udy size. Lines ep esen 95% con idence in e als. The diamond shows he summa y s a is ic o he 11 esul s om he se en included s udies. The solid line indica es an odds a io o 1.0. OR: odds a io. Since P o ape iles, SX and S1, we e he mos used o co onal p e la ing in he in- cluded s udies, a new me a-analysis, using he same model, was ca ied ou including only he esul s o he i e s udies ha pe o med p e la ing wi h P o ape iles [21,23,25,27,28] . The Tau 2 es was no signi ican (p= 0.34), and he e ogenei y was 10%. The calcula ed