Abstract Aim: This ex vivo study aimed to assess the effect of preendodontic build-up (PEB) on irrigant penetration into dentinal tubules using confocal laser scanning microscopy (CLSM) and to compare two different PEB materials. Materials and Methods: Sixty-four extracted mandibular first premolars with single canals were standardized and randomly allocated into four groups ( n = 16): Group I – no PEB with syringe irrigation, Group II – no PEB with sonic activation, Group III – liquid rubber dam PEB with sonic activation, and Group IV – composite resin PEB with sonic activation. Root canals were prepared up to size 30/0.06 using rotary instruments. 5.25% NaOCl labeled with rhodamine B was used as the irrigant. Specimens were sectioned at coronal, middle, and apical levels and evaluated under CLSM to measure maximum irrigant penetration depth. Data were analyzed using Kruskal–Wallis and Friedman tests ( P ≤ 0.05). Results: Irrigant penetration was significantly greater in groups with PEB compared with those without PEB at all canal levels ( P < 0.0001). Group IV demonstrated the highest penetration, particularly in the apical third. Conclusion: PEB significantly enhances irrigant penetration, especially in the apical third. Establishing an effective coronal reservoir, regardless of the build-up material used, improves irrigation efficacy.
Fuke et al. (2026) studied this question.