Adaptation of mineral trioxide aggregate to dentine walls compared with other root-end filling materials: A systematic review

Bacterial sealing ability of calcium silicate-based sealer for endodontic surgery: an in-vitro study

BACKGROUND

Apical surgery with standard retrograde maneuvers may be challenging in certain cases. Simplifying apical surgery to reduce operating time and streamline retrograde manipulation is an emerging need in clinical endodontics.

AIM OF THE STUDY

The aim of the study was to compare the bacterial sealing ability of a calcium silicate-based sealer with the single cone technique combined with root end resection only, and calcium silicate-based sealer as a retrograde filling versus MTA retrofilling, and to analyze bacterial viability using confocal laser scanning microscope (CLSM).

MATERIALS AND METHODS

In this in vitro experimental study, 50 extracted human maxillary incisor teeth were instrumented and randomly divided into five groups: three experimental groups, a positive control group, and a negative control group (n = 10/group). In the experimental groups, the roots were obturated using the single cone technique (SCT) and a calcium silicate-based sealer. In group 1, the roots were resected 3 mm from the apex with no further retrograde preparation or filling. In groups 2 and 3, the roots were resected, retroprepared, and retrofilled with either a calcium silicate-based sealer or MTA, respectively. Group 4 (positive control) was filled with a single gutta-percha cone without any sealer. In group 5 (negative control), the canals were left empty, and the roots were sealed with wax and nail varnish. A bacterial leakage model using Enterococcus faecalis was employed to assess the sealing ability over a 30-day period, checking for turbidity and analyzing colony forming units (CFUs) per milliliter. Five specimens from each group were examined using CLSM for bacterial viability. Data for the bacterial sealing ability were statistically analyzed using chi-squared and Kruskal-Wallis tests.

RESULTS

The three experimental groups did not show significant differences in terms of bacterial leakage, or bacterial counts (CFUs) (P > 0.05). However, significant differences were observed when comparing the experimental groups to the positive control group. Notably, the calcium silicate-based sealer, when used as a retrofilling, yielded the best sealing ability. CLSM imaging revealed viable bacterial penetration in all the positive control group specimens while for the experimental groups, dead bacteria was the prominent feature seen.

CONCLUSION

Within the limitations of this study, it could be concluded that the bacterial sealing ability of calcium silicate-based sealer with the single cone technique combined with root end resection only and calcium silicate-based sealer as a retrograde filling were comparable with MTA retrofilling during endodontic surgical procedures.

A Study on Nanoleakage of Apical Retrograde Filling of Premixed Calcium Silicate-Based Cement Using a Lid Technique

This study aimed to compare the nanoleakage of retrograde fillings with premixed calcium silicate-based putty and mineral trioxide aggregate (MTA), using two different techniques (traditional and Lid). Sixty-four extracted human teeth were decoronated, then root canals and ends were instrumented for retrograde filling and divided into four groups according to the retrograde filling technique: the traditional and the Lid technique. Each group (n = 15) was filled with Ceraseal + Well-Root putty, Well-Root putty, Ceraseal + ProRoot MTA, and ProRoot MTA. The nanoleakage was evaluated using the Nanoflow device (IB Systems) on days 1, 3, 7, 15 and 30. Data were collected twice per second at the nanoscale (nL/s) and calculated after archiving the stabilization of fluid flow. The Kruskal-Wallis and Mann-Whitney U-tests were used for statistical analysis. All groups showed enhanced sealing ability over time. Regardless of filling materials, the Well-Root putty, Ceraseal+Well-Root putty, and Ceraseal+ProRoot MTA groups indicated less nanoleakage than the ProRoot MTA group in the first week of evaluation (p < 0.05). Although all groups did not show significant differences after 2 weeks, the Ceraseal+ProRoot MTA group leaked less than ProRoot MTA on Days 3 and 7 (p < 0.05). The scanning electron microscopic examined good adaptation to the cavity wall, which was similar to nanoleakage results. Premixed calcium silicate-based putty retrograde filling material alone and using the "lid technique" were shown to be faster and less prone to nanoleakage when compared to MTA.

Interfacial adaptation of NeoMTA Plus, BioRoot RCS and MTA in root-end cavities: A micro-CT study

AIM

This study aimed to use the micro-computed tomography to evaluate the interfacial adaptation and the presence of gaps of NeoMTA Plus, BioRoot RCS, and MTA in the root-end cavities.

METHODOLOGY

Thirty standardized bovine roots measuring 15 mm in length were selected. Chemical-mechanical preparation was performed up to instrument #80 and obturation with the cold lateral compaction technique with cement based on zinc oxide and eugenol. The roots were kept at 37°C for 7 days. Afterward, apicectomy of the apical 3 mm and a root-end filling cavity was performed at 3 mm depth. Micro-computed tomography (micro-CT) was performed to measure the volume of the retroactivity. The roots were divided by stratified randomization into three groups according to the retro-end filling material: NeoMTA Plus, BioRoot RCS, and MTA. A new micro-CT was performed to assess the presence of voids in the root-end filling material and between it and the canal wall. One-way ANOVA and Tukey tests were performed using the BioEstat 4.0 program.

RESULTS

There was no difference in the initial volume values of the root-end cavities (p > .05). After the insertion of root-end filling materials, the most significant volumes of voids were observed in the NeoMTA Plus group (p < .05), with no difference for the BioRoot RCS and MTA Angelus groups (p > .05).

CONCLUSION

Micro-computed tomography showed that MTA and BioRoot RCS have better interfacial adaptation and presented fewer number of gaps than NeoMTA Plus when used as root-end filling materials.

RESEARCH HIGHLIGHTS

Micro-computed tomography evaluation of different root-end fillings materials.

Clinical applications of calcium silicate-based materials: a narrative review

Calcium silicate-based materials are hydrophilic materials with biocompatibility and bioactivity properties. Despite many advantages, they might present some problems related to discolouration, setting time, manipulation and solubility depending on the composition of the product and the type of clinical application. Calcium silicate-based materials can be evaluated under two types according to their intended use: calcium silicate-based cements (CSCs) and calcium silicate-based sealers (CSSs). CSCs can be used in many endodontic procedures including perforation repair, resorption repair, apical barriers, guided endodontic repair, vital pulp treatment, endodontic surgery, root fractures and root canal filling as a core obturation material. CSSs are available for use with gutta-percha to obturate root canals using cold and warm techniques, including the sealer-based obturation technique. The purpose of this review is to evaluate the available literature on CSCs and CSSs and to provide up-to-date information and recommendations for their clinical applications.

Materials for retrograde filling in root canal therapy

BACKGROUND

Root canal therapy is a sequence of treatments involving root canal cleaning, shaping, decontamination, and obturation. It is conventionally performed through a hole drilled into the crown of the affected tooth, namely orthograde root canal therapy. When it fails, retrograde filling, which seals the root canal from the root apex, is a good alternative. Many materials are used for retrograde filling. Since none meets all the criteria an ideal material should possess, selecting the most efficacious material is of utmost importance. This is an update of a Cochrane Review first published in 2016.

OBJECTIVES

To determine the effects of different materials used for retrograde filling in children and adults for whom retrograde filling is necessary in order to save the tooth.

SEARCH METHODS

An Information Specialist searched five bibliographic databases up to 21 April 2021 and used additional search methods to identify published, unpublished, and ongoing studies. We also searched four databases in the Chinese language.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) that compared different retrograde filling materials, with the reported success rate that was assessed by clinical or radiological methods for which the follow-up period was at least 12 months.

DATA COLLECTION AND ANALYSIS

Records were screened in duplicate by independent screeners. Two review authors extracted data independently and in duplicate. Original trial authors were contacted for any missing information. Two review authors independently assessed the risk of bias of the included studies. We followed Cochrane's statistical guidelines and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included eight studies, all at high risk of bias, involving 1399 participants with 1471 teeth, published between 1995 and 2019, and six comparisons of retrograde filling materials. - Mineral trioxide aggregate (MTA) versus intermediate restorative material (IRM): there may be little to no effect of MTA compared to IRM on success rate at one year, but the evidence is very uncertain (risk ratio (RR) 1.09, 95% confidence interval (CI) 0.97 to 1.22; I2 = 0%; 2 studies; 222 teeth; very low-certainty evidence). - MTA versus super ethoxybenzoic acid (Super-EBA): there may be little to no effect of MTA compared to Super-EBA on success rate at one year, but the evidence is very uncertain (RR 1.03, 95% CI 0.96 to 1.10; 1 study; 192 teeth; very low-certainty evidence). - Super-EBA versus IRM: the evidence is very uncertain about the effect of Super-EBA compared with IRM on success rate at 1 year, with results indicating Super-EBA may reduce or have no effect on success rate (RR 0.90, 95% CI 0.80 to 1.01; 1 study; 194 teeth; very low-certainty evidence). - Dentine-bonded resin composite versus glass ionomer cement: compared to glass ionomer cement, dentine-bonded resin composite may increase the success rate of the treatment at 1 year, but the evidence is very uncertain (RR 2.39, 95% CI 1.60 to 3.59; 1 study; 122 teeth; very low-certainty evidence). Same result was obtained when considering the root as unit of analysis at one year (RR 1.59, 95% CI 1.20 to 2.09; 1 study; 127 roots; very low-certainty evidence). - Glass ionomer cement versus amalgam: the evidence is very uncertain about the effect of glass ionomer cement compared with amalgam on success rate at one year, with results indicating glass ionomer cement may reduce or have no effect on success rate (RR 0.98, 95% CI 0.86 to 1.12; 1 study; 105 teeth; very low-certainty evidence). - MTA versus root repair material (RRM): there may be little to no effect of MTA compared to RRM on success rate at one year, but the evidence is very uncertain (RR 1.00, 95% CI 0.94 to 1.07; I2 = 0%; 2 studies; 278 teeth; very low-certainty evidence). Adverse events were not assessed by any of the included studies.

AUTHORS' CONCLUSIONS

Based on the present limited evidence, there is insufficient evidence to draw any conclusion as to the benefits of any one material over another for retrograde filling in root canal therapy. We conclude that more high-quality RCTs are required.

Micro-computed tomographic evaluation of the flow and filling ability of endodontic materials using different test models

Objectives

This study compared the flow and filling of several retrograde filling materials using new different test models.

Materials and Methods

Glass plates were manufactured with a central cavity and 4 grooves in the horizontal and vertical directions. Grooves with the dimensions used in the previous study (1 × 1 × 2 mm; length, width, and height respectively) were compared with grooves measuring 1 × 1 × 1 and 1 × 2 × 1 mm. Biodentine, intermediate restorative material (IRM), and mineral trioxide aggregate (MTA) were evaluated. Each material was placed in the central cavity, and then another glass plate and a metal weight were placed over the cement. The glass plate/material set was scanned using micro-computed tomography. Flow was calculated by linear measurements in the grooves. Central filling was calculated in the central cavity (mm³) and lateral filling was measured up to 2 mm from the central cavity.

Results

Biodentine presented the least flow and better filling than IRM when evaluated in the 1 × 1 × 2 model. In a comparison of the test models, MTA had the most flow in the 1 × 1 × 2 model. All materials had lower lateral filling when the 1 × 1 × 2 model was used.

Conclusions

Flow and filling were affected by the size of the test models. Higher grooves and materials with greater flow resulted in lower filling capacity. The test model measuring 1 × 1 × 2 mm showed a better ability to differentiate among the materials.

Micro-computed tomography high resolution evaluation of dimensional and morphological changes of 3 root-end filling materials in simulated physiological conditions

The aim of this study was to evaluate volumetric and morphological stability of 3 root-end filling materials in addition to porosity and interface voids, using micro-computed tomography (µCT) in high resolution and a highly accurate approach for image analysis. Following root-end resection and apical preparation, two-rooted maxillary premolars were divided into three groups, according to the filling materials: White MTA Angelus, Biodentine, and IRM. Samples were scanned by µCT at 5 µm after the setting time and at time intervals of 7 and 30 days after immersion in phosphate-buffered saline (PBS). Volumetric and morphological changes besides material porosity and interface voids were evaluated by comparing initial values and those obtained after immersion. Data were analyzed statistically, using ANOVA and t-tests (α = 0.05). All materials showed volumetric stability. Regarding the morphological changes, Biodentine had a significant thickness reduction after storage in PBS when compared with MTA. Biodentine also showed an increase in porosity, as well as in percentage and thickness of voids after 30 days of immersion. In conclusion, µCT in high resolution and an accurate image analysis approach may be used to evaluate morphological changes of endodontic materials. Although Biodentine showed suitable adaptability and lower values of porosity than MTA, after PBS immersion there was a dimensional reduction of this material, besides an increase in porosity and interface voids.