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

Abstract

Aim. To conduct a systematic review and meta-analysis according to the following PICO question: in extracted human permanent teeth, does preflaring, compared with unflared canals, influence the accuracy of WL determination with EAL? Material and Methods. A systematic review was conducted according to the PRISMA checklist, using the following databases: PubMed, Science Direct, Scopus, and Web of Science. Studies related to WL determination using EAL both in preflared and unflared root canals of extracted human teeth were included. The outcome of interest was the accuracy of the electronic WL determination. A quality assessment of the included studies was performed, determining the risk of bias. The meta-analyses were calculated with the 5.4 RevMan software using the inverse variance method with random effects. PROSPERO registration: CRD42021243412. Results. Ten experimental studies fulfilled the inclusion criteria, and most of them found that preflaring increases the accuracy of the EALs in WL determination. The calculated OR was 1.98 (95% CI = 1.65–2.37; p < 0.00001; I2 = 10%), indicating that the determination of WL by EALs is almost twice as accurate in preflared canals. The accuracy of Root ZX in WL determination increases more than three times (OR = 3.25; p < 0.00001). Preflaring with Protaper files significantly increases the accuracy of EALs (OR = 1.76; p < 0.00001). The total risk of bias of the included studies was low. No obvious publication bias was observed. Conclusions. The results indicate a significant increase in the accuracy of WL determination with EAL after preflaring, doubling the percentage of exact measurements. Preflaring should be recommended as an important step during mechanical enlargement of the root canal, not only because it improves the access of the files to the canal, but also because it allows one to obtain more accurate electronic determinations of WL.

Análise Comparativa Da Precisão De Dois Localizadores Foraminais Eletrônicos: Root Zx E Finepex

“…O preparo prévio do terço cervical permite que o instrumento chegue à região apical de forma mais livre, aumentando a precisão na leitura do localizador. 2,18,19 Melo et al 20 (2020) testaram 3 aparelhos LFE em três diferentes situações: sem preparo cervical prévio, com preparo realizado com instrumento #25.06 (preparo conservador) e com preparo utilizando instrumento #25.12 (preparo convencional). Embora os aparelhos testados tenham apresentado precisão satisfatória mesmo quando o preparo cervical não foi realizado, o preparo cervical convencional aumento de forma significante a precisão de todos os aparelhos.…”

The effect of coronal pre-flaring and root canal irrigant on apex locators’ accuracy: an in-vitro study

“…This coincides with the results of Pegum Unsal Peker et al, who concluded that Raypex 6 is not influenced by irrigation solutions because of its multifrequency technology, which shows precise WL results. 9,37 The 6 th generation apex locator is believed to be less sensitive to external factors that increase measuring reliability, 38 such as the number and taper of the files used in coronal pre-flaring, which may influence the enlargement of the coronal portion of the canal. 39 The sixth generation EALs have been proven to have a preliminary determination of canal moistness, and based on the constant determined moisture, the sixth-generation EALs adapt the measuring method for either a dry or wet root canal environment.…”

Root canal length changes during mechanical preparation due to different cervical enlargement patterns

“…4 Flaring the cervical third of the root also improves its medium and apical third cleaning 5,6 and reduces the amount of debris that could be extruded from the apical foramina 7,8 and also a flare-up incidence. 4,9 Cervical preflaring may also reduce the instrument fracture incidence 10,11 and allow a more precise electronic odontometry performance, [12][13][14] given that the endodontic file could be better adjusted to the apical third of the root. [15][16][17] Declaration of Interests: The authors certify that they have no commercial or associative interest that represents a conflict of interest in connection with the manuscript.…”