The comparison of strip perforation repair using proroot MTA and calcium silicate-based sealer with cold hydraulic technique; bacterial leakage and micro-CT studies

Abstract

Background

Strip perforations present a significant challenge in endodontic treatment due to the complexity of achieving an efficient seal, which can directly impact treatment outcomes. While bioceramic materials are commonly used for root repair, limited evidence exists regarding their effectiveness in sealing strip perforations. This study aims to investigate the sealing ability of ProRoot MTA, AH Plus, and iRoot SP in strip perforation repair using a bacterial leakage model, as well as to evaluate the presence of gaps and voids using micro-computed tomography (micro-CT).

Methods

Forty human mandibular molars were used in this study. A strip perforation was created on the distal surface of the mesial root, between the coronal and middle thirds, using a Gate Glidden drill size #3. Tooth specimens were divided into three experimental groups (n = 12) and two control groups (positive and negative control groups, n = 2 each). The perforations in the experimental groups were repaired with ProRoot MTA, AH Plus using the lateral compaction technique, and iRoot SP using the cold hydraulic obturation technique. The sealing performance of the repair materials was assessed using a bacterial leakage model with Enterococcus faecalis (ATCC 29212). Leakage was monitored over 45 days, and statistical analysis was conducted using Kaplan-Meier survival curve analysis. Gaps and voids at the perforation sites were evaluated with micro-CT analysis, and statistical comparisons were made using one-way ANOVA.

Results

The ProRoot MTA group exhibited the highest percentage of non-leakage samples (75.0%), followed by the iRoot SP group (66.7%) and the AH Plus group (41.7%). However, no statistically significant differences were detected among the groups. The micro-CT analysis demonstrated that the mean percentage of gaps and voids was significantly higher in the AH Plus group compared to both the ProRoot MTA and iRoot SP groups (p < 0.05).

Conclusion

ProRoot MTA showed the highest proportion of non-leakage samples, followed by iRoot SP and AH Plus, with no significant differences in leakage time. Micro-CT analysis revealed significantly more voids in the AH Plus group. Within the study’s limitations, bioceramic sealers showed comparable sealing performance to MTA. Further studies are needed to confirm these findings.

Background

Strip perforation of the root canal is an iatrogenic complication, typically resulting from the removal of cervical dentin during access preparation with Gates-Glidden drills or from excessive instrumentation during the preparation of curved root canals [1–3]. This condition is most commonly found in the mesiobuccal roots of maxillary molars, the mesial roots of mandibular molars, and in roots with thin canal walls [4]. Clinically, strip perforations can be identified through signs such as bleeding from the canal or the occurrence of unexpected pain despite the use of local anesthesia [5]. The apex locator is a useful diagnostic tool, as a zero reading when a file is placed in the perforation site suggests communication with the periodontal ligament [6]. In some cases, strip perforations may only be identified after the completion of root canal filling, with subsequent radiographic examination revealing sealer extrusion beyond the root boundaries, which indicates communication between the root canal system and surrounding tissues [7].

Previous studies have investigated various factors that influence the prognosis of perforation repair. These factors include the size and location of the perforation, the duration of the repair procedure, bacterial contamination, and the physio-biological properties of the repair materials [3, 8]. Unlike furcal or apical perforations, strip perforations are characterized by a larger affected area and irregular edges at the perforation site, which pose challenges in achieving an effective seal [4]. Therefore, the success of perforation repair is significantly improved when the defect is accurately diagnosed and repaired with appropriate materials [9, 10].

The materials used for repairing root perforations must exhibit several essential properties, such as adequate sealing ability, biocompatibility, dimensional stability, insolubility, radiopacity, and ease of placement within the root canal [3]. Mineral trioxide aggregate (MTA) is regarded as the gold standard for repairing root perforations. In addition to its desirable characteristics, such as effective sealing, biocompatibility, and radiopacity, MTA also exhibits antibacterial properties and the ability to set in the presence of blood [11]. However, the use of MTA has limitations, including tooth discoloration and a prolonged setting time, which can complicate handling and make the procedure more technique-sensitive [12].

In endodontics, calcium silicate-based sealers have emerged as an alternative to traditional resin-based sealers. These materials offer several beneficial properties, including biocompatibility, chemical stability, hydrophilicity, flowability, radiopacity, and slight expansion tendencies [13]. In 2019, Castagnola et al., reported highlighted the successful repair of a root canal perforation using a calcium silicate-based sealer (EndoSequence BC sealer, Brasseler USA, Savannah, GA, USA), with a follow-up period of four years [14].

Given the various benefits of calcium silicate-based root canal sealers, it is expected that this material may demonstrate superior sealing capabilities in repairing strip perforations. However, the current literature lacks sufficient evidence to support this expectation. Therefore, this study aims to evaluate the sealing ability of ProRoot MTA, iRoot SP, and AH Plus in repairing strip perforations using the bacterial leakage method. Additionally, the presence of gaps and voids at the perforation site will be analyzed using micro-CT imaging.

Materials and methods

The study protocols were ethically approved by the Institutional Review Board of the Faculty of Dentistry and Faculty of Pharmacy, Mahidol University (MU-DT/PY-IRB 2023/050.1311).

Sample size calculation

The sample size in this study was estimated using the result from a previous study [15]. A power analysis for comparing multiple proportions was performed using nQuery software (version 9.2.1.0), with a significance level (α) of 0.05, power of 80%, and an effect size of 0.240. The minimum required sample size was 12 specimens per experimental group. Additionally, two teeth were allocated to each of the positive and negative control groups, resulting in a total of 40 teeth used in this study.

Tooth selection

The extracted human permanent mandibular molar teeth were cleaned to remove any debris and soft tissue remnants and stored in a 0.12% thymol solution (M Dent, Bangkok, Thailand). Periapical radiographs were taken in both mesiodistal and buccolingual directions to exclude teeth with previous endodontic treatments, root caries, resorption, fractures, or immature apices. Mandibular molars with mesial roots that exhibited Type II or Type IV Vertucci canal configurations, root curvatures of less than 30° [16], mesial root lengths of 15 ± 2 mm, with initial apical files of size 15 or smaller were selected for sample preparation.

Tooth preparation

Endodontic access cavities were initially prepared using a high-speed round diamond bur size 018 (Jota, Rüthi, Switzerland) for entry, followed by a D8 bur (Jota, Rüthi, Switzerland) for the lateral extension of the cavity wall. The pulpal tissue was removed, and the root canal orifices were identified. Apical patency was confirmed with a #10 K-File (Dentsply Sirona, Ballaigues, Switzerland), and the working length was recorded when the K-File appeared from the apical foramen. The distal root was then horizontally sectioned perpendicular to the long axis of the tooth, 1 mm below the furcation, using a high-speed diamond disc. The furcation area, mesio-lingual, and distal root canal orifices were gently treated with Prime&Bond universal™ (Dentsply Sirona, Ballaigues, Switzerland) mixed with a self-cure activator (Dentsply Sirona, Ballaigues, Switzerland) for 20 s. After allowing the solvent to evaporate for at least 5 s with dry air, the adhesive/activator mixture was light-cured for 20 s using a light-curing unit (Elipar™ DeepCure-S LED Curing Light; 3 M ESPE, Australia). The furcation area, mesio-lingual, and distal root canal orifices were subsequently filled with Core-X™ Flow (Dentsply DeTrey, Konstanz, Germany).

The mesiobuccal root canals were shaped using a sequence of ProTaper Gold files (Dentsply Maillefer, Ballaigues, Switzerland) up to F4 (40/0.06v) at 250 rpm with continuous movement. The canals were irrigated with 2.5% sodium hypochlorite (NaOCl) (M Dent, Bangkok, Thailand) using a disposable syringe and a 25-gauge needle. To remove the smear layer, the canals were rinsed with 3 mL of 17% ethylenediaminetetraacetic acid (EDTA) (M Dent, Bangkok, Thailand) for 1 min, followed by a final rinse with 5 mL of 2.5% NaOCl. Finally, the canals were dried using paper points.

Strip perforations were created on the distal surface of the mesial root, specifically between the coronal third and middle third, by gently advancing toward the danger zone using Gates Glidden drills size #3 (Jota, Rüthi, Switzerland). To ensure reproducibility, all perforations were prepared by a single calibrated operator. The perforation depth was controlled at approximately 2.5 mm in the inciso-apical direction. The area of each perforation was measured under a light microscope (Olympus CX31, Olympus, Tokyo, Japan), and teeth exhibiting more than ± 20% deviation from the mean perforation area were excluded. To verify standardization across groups, the mean perforation areas were statistically compared using one-way ANOVA, confirming no significant differences among experimental groups. The pulp chamber and perforation site were irrigated with 2.5% NaOCl and dried using paper points. The specimens were stored in 0.1% thymol solution until further use. The silicone impression material (Express™ XT Putty soft; 3 M Deutschland GmbH, Neuss, Germany) was employed as a matrix to replicate the bony socket. The tooth was positioned into the unset silicone, then removed after complete polymerization. Subsequently, the silicone at the strip perforation area was carefully removed to create a space beneath the perforation site, which was then filled with a moist cotton pellet to simulate the moisture of the surrounding soft tissues (Fig. 1).

Fig. 1.

The strip perforation tooth sample with silicone impression

The perforation repairs

The samples were randomly divided into 3 groups using a blocked randomization technique. The obturation and repair materials applied to each experimental group were as follows:

Group 1 ProRoot MTA (n = 12): The mesiobuccal canal with the perforation was obturated using ProRoot MTA (Maillfer, Dentsply, Switzerland). The material was applied from the apex to the orifice region using an MTA gun (MTA Delivery Systems; DDS Innotech, Bangkok, Thailand) and compacted with fitted pluggers.

Group 2 AH Plus with gutta percha (n = 12): The AH Plus sealers (Dentsply Maillefer, Ballaigues, Switzerland) were applied inside the root canals with a lentulo spiral size 40 (Dentsply Maillefer, Ballaigues, Switzerland). Gutta-percha (Densply Maillefer, Ballaigues, Switzerland) was employed to obturate the root canals using the lateral compaction technique.

Group 3 iRoot SP with gutta percha (n = 12): The iRoot SP (Innovation BioCeramix Inc., BC, Canada) was applied by inserting a syringe with an intra-canal tip into the canal at the coronal one-third. Then the small amount of sealer was gently dispensed into the canal. The matched gutta-percha cone (Dentsply Maillefer, Ballaigues, Switzerland) was coated with a thin layer of the sealer and slowly inserted into the canal to the working length and then cut the coronal portion of the cone using a heated instrument.

Positive control (n = 2): The strip perforation was not repaired with any material.

Negative control (n = 2): Teeth without strip perforation.

Periapical radiographs were taken in a buccolingual direction for all specimens to evaluate the quality of the repair material at the perforation sites. After the preparation, all specimen groups were stored at 37 °C and 100% humidity for 24 hours.

Bacterial leakage test

All external root surfaces of the tooth samples in Groups 1, 2, 3, and the Positive control group were covered with two layers of nail varnish (Revlon, New York, NY, USA), leaving a 1 mm area around the perforation site exposed. In the Negative control group, the entire root surface of the teeth was completely covered with nail varnish.

The model for the bacterial leakage test consisted of two chambers: the upper chamber containing the tooth sample and the lower chamber containing the culture media. First, the tooth sample was inserted into the upper chamber, which was a 5-ml microcentrifuge tube with the bottom cut off. The perforation site protruded approximately 2 mm from the bottom of the tube. The space between the tube wall and the tooth was sealed with Sticky Wax™ (Kerr Corporation, California, USA) and coated with nail varnish. Sterile distilled water was added to the pulp chamber of each tooth, and a plunger from a 10 mL disposable syringe was gently pressed into the upper chamber to evaluate the sealing integrity. Specimens that exhibited leakage of water through the bottom of the tube were excluded from the study. After sealing validation, the entire upper chamber assembly was sterilized using ethylene oxide gas for 18 h prior to bacterial inoculation.

The lower chamber consisted of a sterile, screw-capped glass culture tube containing 40 mL of Brain Heart Infusion (BHI) broth (Bacto™ Brain Heart Infusion; Becton, Dickinson and Company, Franklin Lakes, NJ, USA). The upper chamber was aseptically placed in the lower chamber, with the perforation area of the tooth immersed in BHI broth (Fig. 2). The models were incubated at 37 °C for 24 hours (Heraeus B 5060 EK-CO2; Heraeus, Hanau, Germany) for the sterility test. Only models without any growth turbidity were used for the bacterial leakage test.

Fig. 2.

The Bacterial leakage model

Enterococcus faecalis (ATCC 29212) was employed as the test bacteria. Prior to the test, 3–5 colonies from a BHI agar plate were transferred to BHI broth and incubated at 37 °C for 8–12 h. After incubation, the bacterial suspension’s turbidity was adjusted to 0.5 McFarland standard. An aliquot of 200 µL of this suspension was then added to the upper chamber of the bacterial leakage model. The models were incubated at 37 °C with 100% humidity, and the media in the upper chamber was replaced every other day to ensure bacterial viability.

The turbidity of the medium in the lower chamber was detected daily, as it indicated bacterial leakage. Upon observing turbidity, gram staining was performed to confirm the growth of Enterococcus faecalis. The day on which leakage was detected for each sample was recorded throughout the 45-day observation period.

Micro-CT analysis

Micro-CT analysis was performed on all tooth samples following the bacterial leakage test. The samples were first sterilized using ethylene oxide gas, then dried and mounted onto custom stubs. Each sample was fixed onto a positioning stage and scanned with a high-resolution micro-CT scanner (NeoScan N80 micro-CT, NeoScan, Mechelen, Belgium). The scanning parameters were set to 90 kV, 177 µA, and an image pixel size of 6 μm. After scanning and reconstruction, the acquired images were analyzed using CT analyzer software (Dragonfly Workstation 2022.2, Comet Technologies Canada Inc., Montreal, Canada). The volume of gutta percha cone/sealer, gaps, and voids was calculated, and 3D visualizations were generated.

Statistical analysis

One-way ANOVA was employed to assess differences in strip perforation size across the experimental groups. For the bacterial leakage test, the time to bacterial leakage was analyzed using Kaplan–Meier survival curves. This method is suitable for time-to-event data, particularly when some specimens do not exhibit the event of interest (i.e., leakage) within the observation period. Comparisons among the experimental groups were performed using the log-rank test to assess statistically significant differences in leakage-free survival times. This approach appropriately accounts for censored data and allows reliable evaluation of performance differences between sealing materials. For the micro-CT analysis, the percentage of total gaps and voids was compared among the experimental groups using one-way ANOVA, with pairwise comparisons conducted using simple linear regression. A significance level of p < 0.05 was set for all statistical tests. All data were analyzed using IBM^® SPSS^® software version 26.0.0.0 (IBM Corp., Armonk, USA).

Results

The means and standard deviations of the strip perforation area for each experimental group were analyzed, revealing no statistically significant differences among the groups (Table 1).

Table 1.

Means and standard deviations of strip perforation area in each experimental group. (n = 12)

Experimental group	Type of repair material	Strip perforation area (mm2) (Mean ± SD)
Group 1	ProRoot MTA	2.15 ± 0.38a
Group 2	AH Plus	2.13 ± 0.38a
Group 3	iRoot SP	2.11 ± 0.42a

The bacterial leakage test

The results of the bacterial leakage test were reported as the day of leakage detection for each sample and the number of leakage/non-leakage samples during the 45-day observation period. The two positive control samples, in which the strip perforation was not repaired with any material displayed growth turbidity of the BHI broth in the lower chamber within 24 hours. In contrast, the two negative control samples did not show any turbidity throughout the experimental period.

None of the experimental groups exhibited non-leakage tooth samples. The highest percentage of non-leakage samples was detected in the ProRoot MTA group (75.0%), followed by the iRoot SP group (66.7%) and the AH Plus group (41.7%). In terms of the day of leakage detection, the ProRoot MTA group showed the longest mean day of leakage detection (34.95 ± 5.05), which was comparable to the iRoot SP group (32.50 ± 5.27). The AH Plus group showed the shortest mean day of leakage detection (24.83 ± 5.62). However, the Log-rank test did not reveal any statistically significant differences among the three experimental groups (Table 2). Further analysis using Kaplan-Meier survival curves illustrated the bacterial leakage characteristics, based on leakage time, and the endpoint of leakage for each experimental group over the 45-day observation period, as shown in Fig. 3.

Table 2.

Bacterial leakage of tooth samples in the experimental groups during 45-day using various strip perforation repair materials (n = 12)

Experimental group	Repair material	Number of sample (%)		Day of leakage detection (Mean ± S.D.)
		Non-leakage	Leakage
Group 1	ProRoot MTA	9 (75.0)	3 (25.0)	34.92 ± 5.05a
Group 2	AH Plus	5 (41.7)	7 (58.3)	24.83 ± 5.62a
Group 3	iRoot SP	8 (66.7)	4 (33.3)	32.50 ± 5.27a

Fig. 3.

The Kaplan-Meier survival curves of the bacterial leakage from 3 experimental groups

Micro-CT analysis

The micro-CT analysis demonstrated the presence of gaps and voids in all teeth from all groups. The highest mean percentage of gaps and voids was detected in the AH Plus group (4.71 ± 2.86), which was significantly higher than that of the ProRoot MTA group (2.85 ± 1.76) and the iRoot SP group (2.60 ± 1.73) (p < 0.05) (Table 3). Figure 4 displays representative 3D reconstructions of all groups.

Table 3.

The percentage of total gap/voids area of tooth sample in the experimental groups, evaluated by micro-computed tomographic analysis (n = 12). Statistically significant differences (p < 0.05) between experimental groups are indicated by different lowercase letters

Experimental Group	Repair material	Percentage of total gap/voids (Mean ± S.D.)
Group 1	ProRoot MTA	2.85 ± 1.76a
Group 2	AH Plus	4.71 ± 2.86b
Group 3	iRoot SP	2.60 ± 1.73a

Fig. 4.

Micro-computed tomographic images in 3 dimensions of representative samples from the experimental groups. (G1) ProRoot MTA, (G2) AH Plus, (G3) iRoot SP; The green color shows the strip perforation repair material; the pink color within the repair materials indicates gaps/voids

Discussion

Although numerous studies have evaluated the sealing ability of root repair materials in various perforation models [17–19], none have specifically addressed strip perforations—a challenging procedural complication characterized by irregular internal morphology and thin dentinal walls. Furthermore, comparative investigations involving both ProRoot MTA and iRoot SP using the cold hydraulic obturation technique remain limited. To the best of our knowledge, no prior research has simultaneously assessed both bacterial leakage resistance and micro-computed tomography (micro-CT) structural characteristics of these materials in the context of strip perforation repair.

The simulation of a strip perforation in the tooth model presents a significant challenge. In the present study, the strip perforation model was designed and modified based on a previous study [20]. To ensure uniformity in perforation areas across the experimental groups, the sizes of the strip perforations were measured using a light microscope. The use of one-way ANOVA to assess perforation area among groups showed no statistically significant differences, supporting standardization of the strip perforation model in this study.

Variations in root canal anatomy, morphology, and length among tooth samples in the strip perforation model may influence the sealing ability and bacterial leakage outcomes [21]. To minimize such variability, this study standardized the canal configuration, length, and curvature of the mesial roots. The tooth samples were anatomically matched based on visual examination of periapical radiographs in both the buccolingual and mesiodistal directions. Additionally, the narrow mesiobuccal canals were prepared using nickel-titanium rotary instruments up to a size of 40/0.06v, ensuring a uniform circular shape of the prepared root canals. For future studies, the use of micro-CT is recommended, as it enhances the accuracy of tooth matching and improves the internal validity of the experiment by excluding potential confounding factors, such as microcracks or variations in the mesial roots, which can be more precisely assessed through micro-CT.

Bacterial leakage test was employed in this study due to its greater clinical and biological relevance compared to dye leakage and fluid infiltration tests [22–24]. This method provides clinically significant insights into the sealing ability of repair materials. It evaluates the ability of various materials to seal perforations by assessing the penetration of bacteria through the repaired site from the upper chamber into the lower chamber containing bacterial culture media. The presence of turbidity in the culture medium indicates bacterial leakage and failure of the sealing ability. The number of leakage samples and the time to leakage detection are used to determine the efficacy of the different repair materials [25]. Enterococcus faecalis was chosen as the test bacterium due to its ability to survive in harsh environments, particularly high pH levels. It is commonly associated with persistent apical periodontitis in well-treated root canal obturations, presenting challenges for effective disinfection [26]. The absence of leakage in the negative controls confirmed that the sealing between the upper and lower chambers of the models was intact, while the growth turbidity detected in the lower chamber of the positive controls within 24 hours indicated rapid leakage of E. faecalis through the perforation site. The 45-day observation period was selected based on previous studies to capture the initial period of leakage while minimizing the risk of contamination [27, 28]. However, a limitation of this test is that the quantity of E. faecalis at the time of leakage could not be precisely quantified.

The use of micro-CT in this study allowed for non-destructive three-dimensional analysis of the internal structure at the perforation site. Its primary advantage lies in the ability to visualize voids and gaps with high resolution, without the need for physical sectioning of the specimen [29]. However, micro-CT is limited in its ability to detect nanoscale interfacial leakage pathways or subtle chemical interactions at the material-dentin interface [30]. To overcome these limitations, alternative imaging techniques such as confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) may be employed. These methods provide more detailed information at the surface or molecular level, though they are often destructive and restricted to two-dimensional evaluation [31–33]. Therefore, a multimodal imaging approach combining micro-CT with complementary techniques may provide a more comprehensive understanding in future studies.

The highest percentage of non-leakage samples was detected in the ProRoot MTA group (75.0%). ProRoot MTA is regarded as the gold standard for root perforation repair due to its superior sealing ability and favorable adaptation [11]. This is attributed to the calcium silicate-based material’s hydration reaction, during which tri- and dicalcium silicate components interact with water to form calcium silicate hydrate gel. The product demonstrates dimensional stability and expansion beyond its initial volume upon setting, significantly contributing to the material’s sealing ability [34–36]. Additionally, when calcium hydroxide contacts tissue fluids, it reacts with phosphate ions in the fluids to generate hydroxyapatite at the dentine-material interface, further enhancing sealing [37].

The AH Plus group showed the lowest percentage of non-leakage samples (41.7%) and the highest mean percentage of gaps and voids. These findings align with previous research, which also demonstrated bacterial penetration in root canals obturated with gutta-percha and AH Plus [22, 38]. The epoxy resin sealer tends to shrink during setting, which may lead to compromised sealing ability and potential debonding from the root canal walls [36, 39].

Calcium silicate-based sealers, such as iRoot SP, have been introduced as an alternative to traditional resin-based sealers. In our study, the iRoot SP group exhibited low percentage of gaps and voids. This may be due to the excellent flow capacity of calcium silicate-based sealers and their slight expansion during setting [36]. Moreover, the hydraulic force generated when placing a well-fitted cone into the canal likely facilitated the distribution and penetration of the sealer into the strip perforation. Despite this, the iRoot SP group showed higher sealer extrusion compared to the ProRoot MTA and AH Plus groups, likely due to the excellent flowability of the material. However, in clinical situations, the surrounding periodontium may limit sealer extrusion, which may not be as pronounced as detected in this study. Additionally, calcium silicate-based sealers are biocompatible and bioactive, forming a hydroxyapatite-like precipitate on their surface upon contact with tissue fluids [36, 40, 41].

The antimicrobial properties of the repair materials may influence the outcomes of the bacterial leakage test. The MTA’s antibacterial efficacy is attributed to its high alkalinity during setting, with the ability to maintain a pH of 11–12 for up to 78 days [42–44]. Similar antibacterial effects are detected in calcium silicate-based sealers, although these effects tend to diminish within 7 days post-setting [45].

Although this study did not demonstrate statistically significant differences in bacterial leakage among the tested materials, a numerical trend favoring ProRoot MTA and iRoot SP was observed. This trend is consistent with previous studies that have reported superior sealing ability and dimensional stability of calcium silicate-based materials compared to epoxy resin-based sealers [26, 36, 46]. Additionally, reduced bacterial penetration has been noted in perforation models repaired with calcium silicate-based cements, further corroborating our findings [27, 28].

While the sample size for each group was determined via power analysis based on prior literature [15], it should be noted that the referenced study used a furcal perforation model with different repair materials. Differences in anatomical location and material composition may influence sealing behavior and bacterial leakage outcomes. These discrepancies may have contributed to the lack of statistically significant differences observed between AH Plus and ProRoot MTA in the present study.

This investigation was conducted under in vitro conditions, which inherently limit the ability to replicate the clinical environment, including factors such as periodontal tissue pressure, the patient’s immune response, and long-term aging of materials. Moreover, the relatively small sample size and the use of a single bacterial species (E. faecalis) do not reflect the polymicrobial nature of real-world endodontic infections [47].

Additionally, variability among specimens and the complexity of in vitro models may affect the sensitivity of leakage detection methods. Although the experimental design was carefully controlled, future studies involving larger sample sizes and clinically relevant models are necessary to validate these findings and to better distinguish the sealing capabilities of bioceramic and resin-based sealers.

From a clinical perspective, bioceramic sealers such as iRoot SP may represent a viable alternative for strip perforation repair due to their favorable handling characteristics and compatibility with cold hydraulic obturation techniques. Nevertheless, clinicians should remain mindful of potential material extrusion and anatomical considerations. Further in vivo studies and histological assessments are needed to confirm the translational value of these in vitro results and evaluate long-term clinical outcomes.

Conclusion

ProRoot MTA demonstrated the highest proportion of non-leakage samples, followed by iRoot SP and AH Plus, although no statistically significant differences in leakage times were detected. Micro-CT analysis revealed significantly more interfacial gaps and voids in the AH Plus group. Within the limitations of this in vitro study, bioceramic sealers demonstrated comparable sealing ability to MTA. However, further studies under clinical conditions are needed to confirm these findings and support their potential use in strip perforation repair.

Abbreviations

MTA

Mineral trioxide aggregate

micro-CT

Micro-computed tomography

E. faecalis

Enterococcus faecalis

IAF

Initial apical file

NaOCl

Sodium hypochlorite

EDTA

Ethylenediaminetetraacetic acid

BHI

Brain heart infusion

Authors’ contributions

All authors created study conception and design, M.W. data collecting, analysis and interpretation. All authors reviewed the manuscript.

Funding

Open access funding provided by Mahidol University. This study was supported by a grant from the Endodontics section, Department of. Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Declarations

Ethics approval and consent to participate

Ethical approval for this study was obtained from the Institutional Review Board of the Faculty of Dentistry and Faculty of Pharmacy, Mahidol University (MU-DT/PY-IRB 2023/050.1311). The study was conducted in accordance with the Declaration of Helsinki. The IRB waived the requirement for informed consent, as anonymized extracted teeth were used without human participation, in compliance with national regulations.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.