Effect of Medicaments Used in Endodontic Regeneration Technique on the Chemical Structure of Human Immature Radicular Dentin: An In Vitro Study

Effects of SWEEPS-Activated Irrigation and Other Methods for Elimination of Intracanal Medicaments on Push-Out Bond Strength of NeoMTA2 to Root Dentin: An In Vitro Study

Objectives: This study evaluated the effects of laser-assisted irrigation, conventional syringe irrigation (CSI), and passive ultrasonic irrigation (PUI) for elimination of intracanal medicaments on push-out bond strength (PBS) of NeoMTA2 to root dentin. Materials and Methods: In this in vitro study, 150 extracted single-rooted mandibular premolars were decoronated and standardized with a certain root length. The canals were instrumented to simulate immature roots and randomly assigned to three experimental groups (n = 45) using either triple antibiotic paste (TAP), double antibiotic paste (DAP), or calcium hydroxide (CH) as intracanal medicament and one no-medicament control group (n = 15). After 28 days, the experimental groups were randomly divided into three subgroups (n = 15) according to the irrigation method using either erbium-doped yttrium aluminum garnet (Er:YAG) laser shockwave-enhanced emission photoacoustic streaming (SWEEPS), CSI, or PUI. A dentinal ring was then obtained from the coronal part of each root, and its lumen was densely filled with NeoMTA2. After 1 week, the PBS was measured using a universal testing machine. Data were analyzed by ANOVA and Tukey and Dunnett tests (alpha = 0.05). Results: The interaction effect of the irrigation technique and medicament type on PBS was significant (p < 0.05). The PBS in all groups was significantly lower than the control group (p < 0.01) except in CH-SWEEPS (p = 0.741). In the experimental groups, the PBS of the SWEEPS subgroup was significantly higher than other subgroups (p < 0.001). The PBS of PUI was higher than CSI in CH and TAP groups (p < 0.001). The PBS of CH was significantly higher than TAP in CSI, and DAP and TAP in PUI and SWEEPS groups (p < 0.05). Conclusion: In this in vitro study, regardless of the irrigation method, higher PBS of NeoMTA2 to root dentin was achieved in CH groups compared to TAP. A higher PBS was also achieved when SWEEPS and PUI methods were used to eliminate CH in comparison to TAP and DAP.

Comparative Evaluation of the Effects of Calcium Hydroxide Intracanal Medicament and Antibiotic Paste on Dentin Microhardness: A Systematic Review

An infectious environment is reported to hinder the process of pulp tissue regeneration by damaging the cells responsible for tissue formation, including stem cells in the periapical tissues. Therefore, a sterile environment is critical for pulp tissue regeneration, which can be achieved by copious irrigation and intracanal medicament (ICM) placement. This systematic review compares the effect of calcium hydroxide (Ca(OH)2) and various antibiotic pastes, such as triple antibiotic paste (TAP), modified triple antibiotic paste (MTAP), and double antibiotic paste (DAP), on dentin microhardness when used as ICMs. MeSH terms and specific keywords were used to search Scopus, EBSCOhost, Cochrane Library, and PubMed. In vitro studies that compared the impact of Ca(OH)2 and antibiotic pastes, such as TAP, MTAP, and DAP, on dentin microhardness were included. Data from the included articles were extracted, and their quality was assessed using the revised Quality Assessment Tool for In Vitro Studies (QUIN) tool. Seven articles were included for the qualitative synthesis, and data were extracted from each. Within the scope of this systematic review, Ca(OH)2, an alternative ICM recommended by the American Association of Endodontics Glossary of Endodontic Terms for REPs, showed a lesser reduction in microhardness than TAP. DAP and MTAP caused a reduction in dentin microhardness compared to that of Ca(OH)2.

Antibiofilm effect of Nano chitosan and calcium hydroxide intracanal medications and their effects on the microhardness and chemical structure of radicular dentine

BACKGROUND

Disinfection of the root canal system is a challenge to all clinicians, calcium hydroxide Ca(OH)2, one of the most popular intracanal medications used for this purpose, has some unwanted effects on dentine. This study aimed to investigate the antibiofilm effect of Nanochitosan (CSNPs) and Calcium hydroxide Ca(OH)2 intra canal medications and their effect on the microhardness and chemical structure of radicular dentine.

METHODOLOGY

A total of 52 extracted human mandibular premolars were used. Eighteen premolars were instrumented, sterilized, and inoculated with Enterococcus faecalis (E. faecalis) then divided randomly into 2 groups based on the intracanal medication used: group (A) 2% CSNPs gel and group (B) Ca(OH)2 paste. Antibiofilm effect was evaluated using bacterial counts. For the effect on microhardness, 56 specimens were subjected to Vicker's microhardness test before and after 1 week, and 4 weeks of medication application. Twelve cervical radicular dentine specimens (6 samples per group) were examined using Fourier transform infrared spectroscopy and scanning electron microscope.

RESULTS

Both groups showed a significant reduction in the bacterial count at (p = 0.008) with no significant difference between them (P = 0.605). Ca(OH)2 showed the highest reduction in the microhardness compared to CSNPs groups after 1 week (P = 0.0495) and after 4 weeks (P = 0.0495). FTIR spectrum results revealed that the control group (no treatment) showed the highest significant Phosphate: amide ratio compared to both CSNPs and Ca(OH)2 at p = 0.006. SEM images revealed absence of discernible smear layer in CSNPs treated samples after 4 weeks and all the dentinal tubules were open.

CONCLUSIONS

Nanochitosan gel could be considered as a viable option as an intra canal medication.

Tissue engineering approaches for dental pulp regeneration: The development of novel bioactive materials using pharmacological epigenetic inhibitors

The drive for minimally invasive endodontic treatment strategies has shifted focus from technically complex and destructive root canal treatments towards more conservative vital pulp treatment. However, novel approaches to maintaining dental pulp vitality after disease or trauma will require the development of innovative, biologically-driven regenerative medicine strategies. For example, cell-homing and cell-based therapies have recently been developed in vitro and trialled in preclinical models to study dental pulp regeneration. These approaches utilise natural and synthetic scaffolds that can deliver a range of bioactive pharmacological epigenetic modulators (HDACis, DNMTis, and ncRNAs), which are cost-effective and easily applied to stimulate pulp tissue regrowth. Unfortunately, many biological factors hinder the clinical development of regenerative therapies, including a lack of blood supply and poor infection control in the necrotic root canal system. Additional challenges include a need for clinically relevant models and manufacturing challenges such as scalability, cost concerns, and regulatory issues. This review will describe the current state of bioactive-biomaterial/scaffold-based engineering strategies to stimulate dentine-pulp regeneration, explicitly focusing on epigenetic modulators and therapeutic pharmacological inhibition. It will highlight the components of dental pulp regenerative approaches, describe their current limitations, and offer suggestions for the effective translation of novel epigenetic-laden bioactive materials for innovative therapeutics.

Improving Antimicrobial Properties of GelMA Biocomposite Hydrogels for Regenerative Endodontic Treatment

Regenerative endodontics is a developing field involving the restoration of tooth structure and re-vitality of necrotic pulp. One of the most critical clinical considerations for regenerative endodontic procedures is the disinfection of the root canal system, since infection interferes with regeneration, repair, and stem cell activity. In this study, we aimed to provide the synthesis of injectable biopolymeric tissue scaffolds that can be used in routine clinical and regenerative endodontic treatment procedures using Gelatin methacryloyl (GelMA), and to test the antimicrobial efficacy of Gelatin methacryloyl/Silver nanoparticles (GelMA/AgNP), Gelatin methacryloyl/Hyaluronic acid (GelMA/HYA), and Gelatin methacryloyl/hydroxyapatite (GelMA/HA) composite hydrogels against microorganisms that are often encountered in stubborn infections in endodontic microbiology. Injectable biocomposite hydrogels exhibiting effective antimicrobial activity and non-cytotoxic behavior were successfully synthesized. This is also promising for clinical applications of regenerative endodontic procedures with hydrogels, which are proposed based on the collected data. The GelMA hydrogel loaded with hyaluronic acid showed the highest efficacy against Enterococcus faecalis, one of the stubborn bacteria in the root canal. The GelMA hydrogel loaded with hydroxyapatite also showed a significant effect against Candida albicans, which is another bacteria responsible for stubborn infections in the root canal.

Effect of canal medicaments triple antibiotic paste, Bio-C Temp, and Nano-silver gel activated by visible blue light on canal dentin microhardness and extrusion bond strength of AH plus sealer: A SEM and EDX analysis

AIM

Assessment of contemporary canal medicaments (Triple antibiotic paste (TAP), Bio-C Temp, and Nano silver gel activated by visible blue light on the dentin microhardness (MH) and push-out bond strength (PBS) of AH plus endodontic sealer.

METHOD

Sixty extracted premolars were obtained and decontaminated. Canal cleaning and shaping were performed. The samples were randomly allocated into four groups based on the intracanal medicaments. Group 1= CH paste, Group 2= TAP, Group 3= Bio-C Temp, and Group 4= Nano-silver gel activated by visible blue light. MH assessment was performed using a Vickers Microhardness tester. Forty specimens, ten from each group underwent root canal obturation. PBS and failure mode evaluation were performed. ANOVA and Post Hoc Tukey test were utilized to conduct intra and inter-group comparisons.

RESULTS

The maximum outcome of surface hardness was presented by Group-3 (Bio-C Temp®) specimens. However, minimum scores of MH were displayed by Group 1 (CH) treated teeth. The highest outcomes of EBS were exhibited by the cervical third of Group 3 (Bio-C Temp®) samples. The apical section of Group 4 Teeth with Nano Silver gel activated by visible blue light revealed the lowest scores of bond integrity.

CONCLUSION

Bio-C Temp and TAP proved to be better intracanal medicament than other tested groups in terms of the push-out bond strength of the sealer. TAP displayed lower microhardness as compared to the Bio-C Temp.

Effects of a commercial whitening toothpaste containing hydrogen peroxide and citric acid on dentin abrasion and erosion

BACKGROUND

Hydrogen peroxide (HP) and citric acid (CA), key contributors to toothpaste acidity, can lead to dental loss. This study aimed to compare the amount of abrasion or loss of dentin based on pH, buffering, and concentration of HP and CA in commercial and experimental toothpastes after toothbrushing or immersion.

METHODS

Bovine dentin specimens were randomly assigned to nine solutions. The prepared solutions included two commercial toothpastes (whitening toothpaste [WT] with HP and CA; conventional toothpaste [CT] without HP and CA), reference slurry (RS), two CA solutions (1.92%, CAS1; 0.001%, CAS2), basic solution (7.16% sodium phosphate dibasic [SPDS]), CA phosphate buffer solution (3.58% SPDS and 0.96% CA [CAPB]), HP solution (4%, HPS), and distilled water (DW). Dentin specimens were performed in two treatments: one with only abrasion (10,000 brushings) and one with only immersion (1 h). After treatments, the amount of dentin loss and surface images were measured and observed using noncontact profilometry. Data were analyzed using an one-way analysis of variance and the Tukey test as a post hoc analysis (p < 0.05).

RESULTS

WT with pH 5.0 had lower dentin abrasion than CT and RS after brushing but had higher dentin loss than both after immersion. The dentin surfaces of CAS1, CAPB, and WT were damaged after immersion, whereas HPS, CAS2, CT, SPDS, RS, and DW remained intact after soaking. CAS2 and HPS, which had a pH of 5.0 like WT, did not significantly differ from those of DW after brushing.

CONCLUSIONS

WT containing HP and CA did not cause significant dentin abrasion but may cause additional dentin loss even without brushing. After brushing or immersion, the CA concentration may affect the dentin surface more than the HP concentration included in WT. The amount of abrasion or loss of dentin after brushing or soaking can vary based on the composition, concentration, and buffer in the solution, even if the pH of the solution is similar to pH 5.0.

Efficacy of disinfection procedures performed prior to regenerative endodontic therapy: An integrative review

The aim of this integrative review was to identify whether the disinfection procedures performed prior to regenerative endodontic treatment were effective on biofilm removal from the root canals. The research was based on PubMed, Latin American and Caribbean Health Sciences Literature (Lilacs) and Scientific Electronic Library Online (SciELO) databases. Four articles were selected; one of the studies was in vivo and the others ex vivo. Different disinfection procedures were studied, characterised mainly by the use of intracanal medication, highlighting the double antibiotic paste, triple antibiotic paste and calcium hydroxide paste. Disinfection ability was evaluated against Enterococcus faecalis and multispecies biofilms by using the fluorescence technique and colony forming unit counting, for 7 to 21 days. Double antibiotic paste and triple antibiotic paste demonstrated excellent antibiofilm activity, unlike CH paste that showed limited disinfection, even when associated with different antimicrobial agents. Triple antibiotic paste was the most effective medication against biofilm.

Efficacy of propolis and triple antibiotic paste as intra-canal medicaments for revascularisation of immature teeth in dogs: a comparative study

AIM

Revascularisation is a therapeutic approach for treatment of immature teeth with necrotic pulp. The conventional protocol includes application of triple antibiotic paste (TAP). The present study aimed to compare the efficacy of propolis and TAP as intra-canal medicaments for revascularisation of immature teeth in dogs.

METHODOLOGY

This study was conducted on 20 immature (open-apex) canine teeth in mixed breaded dogs. First, the teeth were exposed to oral environment, followed by intra-canal cleaning and shaping 2 weeks later.. The teeth were divided into two groups. The TAP group received paste comprising of ciprofloxacin, metronidazole, and minocycline (at a concentration of 100 µg/mL), while propolis (15% w/v) was used in the other group. The revascularisation procedure was done by means of sodium hypochlorite, EDTA and distilled water as final irrigant. After dehumidifying and induction of bleeding, mineral trioxide aggregate (MTA) was applied At 6-month follow-up, radiographs were evaluated by two observers regarding root length and thickness, intra-canal calcification, periapical lesions, and apex formation. Data were analysed by the Chi-square and Fisher's exact tests.

RESULTS

There was no significant difference between the TAP and propolis groups in root length or root thickness increase, calcification, related lesions, or apex formation (P > 0.05).

CONCLUSION

Findings of the present study in experimental animals revealed that the efficacy of propolis as an intra-canal medicament is comparable to that of triple antibiotic paste for revascularisation therapy.

Effect of Propolis on Root Dentine Microhardness When Used as an Intracanal Medicament: An In Vitro Study

Application of intracanal medicaments may affect the physical properties of root dentine. Calcium hydroxide (CH), a gold standard intracanal medicament, has proven to decrease root dentine microhardness. A natural extract, propolis, has been shown to be superior to CH in eradicating endodontic microbes, but its effect on the microhardness of root dentine is still not known. This investigation aims to evaluate the effect of propolis on root dentine microhardness compared to calcium hydroxide. Ninety root discs were randomly divided into three groups and treated with CH, propolis, and a control. A Vickers hardness indentation machine with a load of 200 g and dwell time of 15 s at 24 h, 3, and 7 days was used for microhardness testing. ANOVA and Tukey’s post hoc test were used for statistical analysis. A progressive decrease in microhardness values was observed in CH (p < 0.01), whereas a progressive increase was observed in the propolis group (p < 0.01). At 7 days, propolis demonstrated the highest microhardness value (64.43 ± 1.69), whereas CH demonstrated the lowest value (48.46 ± 1.60). The root dentine microhardness increased over time when propolis was applied, while it decreased over time after application of CH on root dentine sections.

Investigating the residual effect of silver nanoparticles gel as an intra-canal medicament on dental pulp stromal cells

BACKGROUND

The aim of this study was to evaluate the indirect effects of residual silver nanoparticles (AgNPs) gel on human dental pulp stromal cells (DPSCs).

METHODS

Ninety-five dentin discs (4x4x1 mm) were prepared from freshly extracted human single-rooted teeth following institutional ethical approval and informed consent. Samples were cleaned, autoclaved, and treated with: 1.5%NaOCl, Saline and 17% EDTA then randomly assigned to 5 groups that received 50 μl of one of the following treatments: 0.01%AgNPs, 0.015%AgNPs, 0.02%AgNPs, Calcium hydroxide (Ca (OH)₂) or no treatment for 1 week. Discs were washed with Saline and 17%EDTA then seeded with DPSCs and incubated for 3 and 7 days. At 24 hours unattached cells were collected and counted. At each time point cytotoxicity (LDH assay), cell viability (live/dead staining and confocal microscopy) and cell proliferation (WST1 assay) were assessed. All experiments were repeated a minimum of 3 times using DPSCs isolated from 3 different donors for each time point assessed (n = 9/group). Statistical analysis was done using One-Way ANOVA followed by Tukey's test and Kruskal Wallis followed by post-hoc comparisons with significance set at p ≤ 0.05.

RESULTS

After 24 hours, the percentage of DPSCs attachment ranged between 92.66% ±4.54 and 95.08% ±1.44 with no significant difference between groups (P = 0.126). Cell viability was ≥92% at 24 hours for all groups. However this percentage dropped to less than 60% at 3 days then started to rise again at 7 days. There was no significant difference in cytotoxicity between different groups at all time points except for 0.01%AgNPs group which had the highest cytotoxicity. DPSCs proliferation increased significantly from 3 to 7 days in all groups except for Ca (OH)₂ which showed lower proliferation rates at both 3 (45.89%) and 7 days (79.25%).

CONCLUSION

Dentin discs treated for 7 days with concentrations of AgNPs gel (0.01-0.02%) allowed more than 90% DPSCs cell attachment after 24 hours. The cytotoxicity and proliferation of DPSCs in response to AgNPs gel were comparable to those with calcium hydroxide. This suggests that AgNPs gel may represent a promising future candidate for clinical use in regenerative endodontics. However, its effects may be concentration-dependent warranting further investigation.

Mesoporous Calcium-Silicate Nanoparticles Loaded with Prussian Blue Promotes Enterococcus Faecalis Ferroptosis-Like Death by Regulating Bacterial Redox Pathway ROS/GSH

Background

Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials that have been used to control drug delivery for many years. Ultrasmall Prussian blue nanoparticles (UPBNPs) showed high peroxidase and catalase-like activities. This study evaluated the antibacterial and antibiofilm properties, mechanism and cytotoxicity of UPBNPs-MCSNs composites synthesized by both as precursors.

Methods

UPBNPs-MCSNs were prepared and characterized. The antibacterial effect of UPBNPs-MCSNs was evaluated by the MTT assay and CFU counting method, and their biosafety was tested by CCK8. Then explore the antibacterial mechanism, including TEM observation of bacterial morphology, and detection of bacterial ROS, LPO and GSH levels. The antibiofilm activity of UPBNPs-MCSNs was tested by E. faecalis biofilm model in human roots. The roots were pretreated with materials and cultured with E. faecalis, and the survival of E. faecalis on the root canal wall was observed by SEM and CLSM.

Results

The results showed that UPBNPs-MCSNs had potent antibacterial and antibiofilm activities. They can aggregate on the dentin surface and significantly inhibit E. faecalis adhesion and colonization. Their antibacterial activity is as effective as NaClO and calcium hydroxide (CH), can significantly prolong the time of bacterial colonization than CH, but have lower cytotoxicity to normal cells. We found that UPBNPs-MCSNs trigger a like classic ferroptosis pathway in bacteria. UPBNPs-MCSNs can induce bacteria to produce ROS and LPO, and reduce GSH level. Moreover, we observed that the metal ions chelator and the antioxidant could block their antibacterial activity.

Conclusion

These results reveal that UPBNPS-MCSNs have high antibacterial and antibiofilm, and can mediate the bacterial redox pathway ROS/GSH like the classical pathway of ferroptosis, providing a theoretical basis for them to develop into a safe and effective novel root canal disinfectant.

Effect of three intracanal medicaments used in pulp regeneration on the push-out bond strength of mineral trioxide aggregate and calcium-enriched mixture: An in vitro study

Background. The bond strength of the materials used as a cervical barrier in the pulp regeneration is essential for the success of treatment. This study aimed to evaluate the effects of triple antibiotic paste (TAP), double antibiotic paste (DAP), and simvastatin as intracanal medicaments on the dislodgement resistance of mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM). Methods. A total of 160 extracted human single-rooted teeth were selected, and root canal preparation was carried out. The teeth in each group were randomly divided into four subgroups: TAP, DAP, simvastatin, and the control group (without intracanal medicament). Four weeks after placing the medicaments, it was removed by sodium hypochlorite, and MTA and CEM were placed in the coronal third of the root canals. After a week, 2-mm-thick dentin disks were prepared from the coronal third of the roots, and the push-out test was performed using a universal testing machine. The data were analyzed using two-way ANOVA and independent t-test at a significance level of 0.05. Results. Regardless of the intracanal medicament, there was no significant difference between the overall bond strength of MTA (59.3±10 MPa) and CEM (55.8±11 MPa) (P=0.6). Furthermore, there were no significant differences in bond strength between the two intracanal medicament groups and the control group (P>0.05). Conclusion. Under the limitations of the current study, DAP, simvastatin, and TAP, as intracanal medicaments, did not adversely affect the push-out bond strength of CEM and MTA.

A Comparative Evaluation of Microhardness and Chemical Structure of Radicular Dentin with Two Combinations of TAP and MTAP: An In Vitro Study

Background

The success of regenerative endodontics depends on various factors and the most vital being the complete eradication of microorganisms in the dentinal tubules. This could lead to changes that leave the radicular dentin prone to fracture.

Aim

The purpose of the present study is to investigate the effects of triple antibiotic paste (TAP) and modified triple antibiotic paste (MTAP) of different concentrations on the microhardness and chemical structure of radicular dentin.

Materials and methods

Human root cylinders were instrumented and randomized into four treatment groups and an untreated control group. Two treatment groups received 1 g/mL TAP or MTAP, and the other two treatment groups received 1 mg/mL methylcellulose-based TAP or MTAP. Cylinders were stored at 100% relative humidity for 4 weeks. Each root cylinder was subjected to a microhardness test before and after treatment. Different sets of radicular dentin specimens were treated as mentioned previously, and were examined using attenuated total reflection Fourier transform infrared spectroscopy.

Results

Significant reductions in microhardness of treated groups was noticed when compared to untreated control roots at 1,000 and/or 500 µm from the pulp-dentin interface.

Conclusion

The use of 1 mg/mL methylcellulose-based TAP and MTAP may minimize the reduction in microhardness of roots compared with the currently used 1 g/mL concentration of these antibiotics.

How to cite this article

Daneswari M, Reddy NV, Chris PA, et al. A Comparative Evaluation of Microhardness and Chemical Structure of Radicular Dentin with Two Combinations of TAP and MTAP: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(S-2):S151-S157.

Effect of triple antibiotic paste on the bond strength of epoxy and methacrylate resin-based sealers to root canal dentin

Purpose:

This study aimed to evaluate the effect of triple antibiotic paste (TAP) as an endodontic intracanal medicament on the bond strength of epoxy and methacrylate resin-based sealers to root canal dentin.

Materials and Methods:

In this in vitro study, 80 single-rooted human mandibular premolars were prepared using ProTaper rotary system. The specimens were randomly divided into a control group (without intracanal dressing) and an experimental group receiving TAP (n = 40). The intracanal dressing was removed after 3 weeks. Then, samples of each group were randomly divided into four subgroups (n = 10) and obturated with gutta-percha and different resin-based sealers. G1: AH Plus, G2: Syntex, G3: EndoREZ, and G4: MetaSEAL. After 1 week, 16 slices of 1 ± 0.1 mm thickness were obtained from the midroots of teeth in each subgroup, and a push-out test was used to measure the bond strength. Slices were examined using a stereomicroscope at 30 × to determine the mode of failure. The data were analyzed using two-way analysis of variance, one-way analysis of variance, and Tukey post hoc tests (α = 0.05).

Results:

Compared to control group, TAP significantly increased the bond strength of MetaSEAL and EndoREZ (P < 0.05). In the control group, epoxy resin-based sealers showed higher bond strength compared to methacrylate ones (P = 0.00). In TAP group, Syntex and EndoREZ showed significantly the greatest and the lowest bond strengths, respectively, (P < 0.05). The analysis of failure modes revealed a predominance of mixed failures in all groups except for Syntex group in which most failures were cohesive.

Conclusions:

TAP significantly increased the bond strength of methacrylate resin-based sealers.

Assessment of pulp sensibility in the mature necrotic teeth using regenerative endodontic therapy with various scaffolds - Randomised clinical trial

Aim

This study aimed to evaluate and compare the possibility of regaining pulp sensibility and objectives of regeneration procedure in mature necrotic teeth using regenerative endodontics.

Materials and Methods

A total of 36 mature necrotic teeth were selected and a regenerative endodontic procedure was performed. A total of four groups, each involving n = 9 teeth per group were randomly grouped as (1) periapical bleeding, (2) platelet-rich fibrin (PRF), (3) collagen, and (4) hydroxyapatite. Pulp testing and radiographic assessment of periapical healing (PH) were recorded at every 3-month interval for 1 year. Readings were compared as qualitative data using the Kruskal-Wallis test to see the inter-group significant difference.

Results

Readings of pulp sensibility revealed non-significant results in all intervals. At 3 and 6 months, 22.3% in the PRF group and 11.15% in collagen group; and at 9 months, 44.4% in PRF group, 33.3% in the collagen group and 22.2% in hydroxyapatite group; and at 12-months, 66.6% in PRF, 44.4% in the collagen group, 33.3% in the hydroxyapatite group and 11.1% in the periapical bleeding group showed a positive response to the cold test. But all groups did not show a positive response to heat and electric pulp testing and showed good PH in all groups at the end of 12 months.

Conclusions

The presence of sensibility to cold test is indicative of the formation of vital pulp-like tissues, which was the highest in the PRF group, followed by the collagen, hydroxyapatite and periapical bleeding groups.

Determination of crown discoloration and fluorescence induced by different medications used in regenerative endodontic procedures: An ex vivo study

Background

Crown discoloration is an undesirable side effect of the use of triple antibiotic paste (TAP) in regenerative endodontic procedures (REPs). The aim of this ex vivo study was to assess the potential for tooth discoloration and induction of fluorescence associated with the use of TAP containing either doxycycline (DOX) or clindamycin (CLIN), and of calcium hydroxide (Ca(OH)2), by spectrophotometric analysis and confocal laser scanning microscopy (CLSM).

Material and Methods

A total of forty single-rooted human teeth extracted by therapeutic indication were used. The root canals were enlarged using the step-back technique up to a K #80 file and were randomly divided into four experimental groups (10 specimens each): i)Ca(OH)2 group, ii)TAP with DOX group, iii) TAP with CLIN group, iv) Control group (no treatment). To quantify the change of color of the different groups of teeth included, the Vita Easyshade advance 4.0 spectrophotometer was used. CLSM was used to determine fluorescence.

Results

After 28 days of action inside the root canal, no extreme discoloration was visible, to the naked eye, in any of the teeth included in the study. Under the conditions of this ex vivo study, TAP with DOX induced the highest crown discoloration among the medicaments tested. In contrast, Ca(OH)2 and TAP with CLIN did not induce crown discoloration after 28 days. The TAP with DOX group presented the highest fluorescence measurements.

Conclusions

Considering the discoloration potential and fluorescence changes in TAP with DOX or other tetracyclines, and the cytotoxic effect of TAPs, we recommend the use of Ca(OH)2 for REPs.

Key words:Discoloration, doxycycline, clinadamycin, calcium hydroxide, endodontics.

The Effects of Double Antibiotic Paste and Amoxicillin-clavulanate Paste Used in Endodontic Regeneration on Microhardness of Radicular Dentine: An In vitro Study

OBJECTIVE

Double antibiotic paste is a root canal medicament used in regenerative endodontics and its long-term exposure to dental hard tissues was shown to reduce its mechanical properties. The amoxicillin-clavulanate paste is a medicament effective against endodontic pathogens and is effective in endodontic regeneration. Its effect on radicular dentine is yet to be investigated. The purpose of this study is to investigate and compare the effects of double antibiotic paste and amoxicillin-clavulanate paste on the microhardness of radicular dentine.

MATERIALS AND METHODS

The root canal of 45 premolars was mechanically prepared and divided into three groups for the placement of intracanal medicament: Group 1 (n = 15) double antibiotic paste, Group 2 (n = 15) amoxicillin-clavulanate paste, and Group 3 control group (n = 15). All the specimens were subject to microhardness testing at 500 and 1000 microns depth for 1 week, 1 month, and 3 months and analyzed.

RESULTS

There is no significant reduction in microhardness of radicular dentin at 1 week on all the three groups. At 1 month and 3 month period, the amoxicillin-clavulanate paste is found to have no significant effect on dentin microhardness when compared to double antibiotic paste.

CONCLUSION

The use of amoxicillin-clavulanate paste as an intracanal medicament does not cause significant weakening of dentin even after its long-term use.

Quercetin as an Auxiliary Endodontic Irrigant for Root Canal Treatment: Anti-Biofilm and Dentin Collagen-Stabilizing Effects In Vitro

Bacterial reinfection and root fracture are the main culprits related to root canal treatment failure. This study aimed to assess the utility of quercetin solution as an adjunctive endodontic irrigant that does not weaken root canal dentin with commitment anti-biofilm activity and bio-safety. Based on a noninvasive dentin infection model, dentin tubules infected with Enterococcus faecalis (E. faecalis) were irrigated with sterile water (control group), and 0, 1, 2, 4 wt% quercetin-containing ethanol solutions. Live and dead bacteria percentages in E. faecalis biofilms were analyzed by confocal laser scanning microscopy (CLSM). Elastic modulus, hydroxyproline release and X-ray photoelectron spectroscopy (XPS) characterization were tested to evaluate the irrigants’ collagen-stabilizing effect. The cytotoxicity was tested by CCK-8 assay. Quercetin increased the proportion of dead bacteria volumes within E. faecalis and improved the flexural strength of dentin compared to control group (p < 0.05). Quercetin-treated dentin matrix had less elasticity loss and hydroxyproline release after collagenase degradation (p < 0.05). Moreover, quercetin solutions revealed an increase in the C-O peak area under both C1s and O1s narrow-scan spectra of XPS characterization, and no cytotoxicity (p > 0.05). Quercetin exhibited anti-biofilm activity, a collagen-stabilizing effect with cytocompatibility, supporting quercetin as a potential candidate for endodontic irrigant.

Do intracanal medications used in regenerative endodontics affect the bond strength of powder-to-liquid and ready-to-use cervical sealing materials?

Aim:

This study evaluated the effect of four intracanal medications commonly used in regenerative endodontic procedures on the bond strength of four calcium silicate-based materials, in which two are powder-to-liquid products (MTA and MTA-HP) and the other are ready-to-use materials (EndoSequence Root Repair Material Fast Set Putty [ERRM] and Bioceramic Repair [BIO-C Repair]).

Methods:

Ten bovine central incisors were selected and 4 slices (1.0 ± 0.1 mm) were prepared from each root. Next, four 0.8-mm wide holes were drilled in each slice and specimens were filled with one of the following intracanal medications: triple antibiotic paste, double antibiotic paste, calcium hydroxide with distilled water, and calcium hydroxide with 2% chlorhexidine gel. After 21 days, holes were filled with one of the materials: MTA, MTA-HP, ERRM, or BIO-C Repair. After storage, push-out test and failure analysis were performed. Data were submitted to analysis of variance in a 4 × 4 factorial scheme. Tukey's test was used for multiple comparisons.

Results:

The use of different interappointment dressings did not influence the results (P > 0.05). ERRM and BIO-C Repair presented significantly higher values than MTA and MTA-HP (P < 0.0001). Specimens showed a 100% occurrence of adhesive failures.

Conclusion:

The use of different intracanal medications presented similar impact on bond strength of calcium silicate-based materials. Ready-to-use ERRM and BIO-C Repair materials presented the best push-out values to dentine, whereas powder-to-liquid MTA and MTA-HP cements showed the lowest results.

Physiopathology of nitric oxide in the oral environment and its biotechnological potential for new oral treatments: a literature review

OBJECTIVES

A narrative review on the NO properties and their relationship with the oral environment describing NO's molecular origin, role, and perspectives regarding oral pathological, physiological, and regenerative processes for future applications and possible use as prevention or treatment in dentistry.

MATERIALS AND METHODS

Pubmed was searched using the word "nitric oxide." Reviews, clinical studies, and experimental studies were eligible for the screening process. Similar search procedures were then performed with the additional search words "conservative dentistry," "orthodontics," "endodontics," "implants," "periodontics," "oral cancer," "pulp revascularization," and "oral surgery." Furthermore, references of included articles were examined to identify further relevant articles.

RESULTS

There is a relationship between NO production and oral diseases such as caries, periodontal diseases, pulp inflammation, apical periodontitis, oral cancer, with implants, and orthodontics. Studies on this relationship and uses of NO, in diagnosis, prevention, and treatment, are being developed. Also, some NO and oral cavity patents have already registered.

CONCLUSIONS

The understanding of how NO can interfere in oral health maintenance or disease processes can contribute to elucidate the disease development and optimize treatment approaches.

CLINICAL RELEVANCE

NO has considerable biotechnological potential and can contribute to improving diagnostics and treating the oral environment. As a biomarker, NO has an important role in the early diagnosis of diseases. Regarding treatments, NO can possibly be used as a regulator of inflammation, anti-biofilm action, replacing antibiotics, inducing apoptosis of cancerous cells, and contributing to the angiogenesis. All these studies are initial considerations regarding the relationship between NO and dentistry.

Effect of Intracanal Medicaments and Irrigants on the Release of Transforming Growth Factor Beta 1 and Vascular Endothelial Growth Factor from Cervical Root Dentin

INTRODUCTION

This study aimed to evaluate (1) the effect of irrigating solutions and intracanal medicaments on the release of transforming growth factor beta 1 (TGF-β1) and vascular endothelial growth factor (VEGF) from cervical root dentin and (2) the effect of associating triple antibiotic paste (TAP) and calcium hydroxide paste (CH) with 2% chlorhexidine (CHX) on TGF-β1 release.

METHODS

First, 119 specimens from roots (cervical thirds) were obtained and were distributed into 5 groups: 2% CHX, 2.5% sodium hypochlorite, TAP, CH, and 10% EDTA by each growth factor (TGF-β1 [n = 8] and VEGF [n = 8]). Then, specimens were distributed as follows (n = 13): TAP + 2% CHX, CH + 2% CHX, and 10% EDTA and treated with irrigating solutions and intracanal medicaments. After the treatments, the specimens were immersed in 10% EDTA (20 minutes), and the solution was analyzed using the enzyme-linked immunosorbent assay. The data were submitted to normality, homogeneity of variance, and Mann-Whitney tests (P < .05).

RESULTS

Significant differences were found between the irrigating solutions (P < .05) and intracanal medicaments for TGF-β1 (P < .05). No VEGF release was detected for any group. Our results showed no significant differences among the TAP + 2% CHX and EDTA groups for TGF-β1 but a significant difference between CH + 2% CHX and the other groups (P < .05).

CONCLUSIONS

The use of 2% CHX as the irrigating solution, CH as the intracanal medicament, and 10% EDTA as the final irrigation provides higher TGF-β1 release from the cervical root dentin, whereas VEGF was not detected. Moreover, TAP and 2% CHX with 10% EDTA as the final irrigation resulted in greater TGF-β1 release from cervical root dentin than CH + 2% CHX.

Observation of an extracted premolar 2.5 years after mineral trioxide aggregate apexification using micro-computed tomography

Although numerous studies have been conducted on apexification using mineral trioxide aggregate (MTA), direct observation of extracted human teeth after the procedure has been rarely reported. This case report describes a mandibular premolar treated 2.5 years ago and extracted recently for orthodontic treatment. The tubercle of the right mandibular premolar of a 12-year-old boy with dens evaginatus was fractured and the pulp was exposed. The tooth was diagnosed with pulp necrosis and asymptomatic periapical abscess. During the first visit, copious irrigation was performed with 2.5% sodium hypochlorite. Calcium hydroxide paste was placed as an intracanal medicament. The sinus tract had disappeared at the second visit after 3 weeks. MTA was applied on to the bleeding point as a 4-mm-thick layer, followed by a 3-mm-thick gutta-percha filling and resin core build-up. After 2.5 years, the tooth and three other premolars were extracted for orthodontic treatment. The right and left mandibular premolars were scanned with micro-computed tomography to determine the root shape and canal anatomy. Irregular root growth was observed and the root outline of the right mandibular premolar differed from that of the contralateral tooth. Apexification with MTA leads to the formation of roots with irregular morphology, without any pulpal space.

A Comparative Evaluation of the Influence of Three Different Vehicles on the Antimicrobial Efficacy of Triple Antibiotic Paste against Enterococcus faecalis: An In vitro Study

Introduction:

The root canal is a hub of numerous microorganisms. Routine endodontic procedures fail to remove the resistant microorganisms such as Enterococcus faecalis.

Aim:

The aim of the present study was to evaluate the influence of different vehicles on the antimicrobial efficacy of triple antibiotic paste (TAP) on E. faecalis infected root canals.

Materials and Methods:

Eighty single-rooted and freshly extracted human teeth were prepared in radicular portion, and pure culture of E. faecalis (ATCC^® 29212™) inoculum was injected into canals of tooth blocks and incubated for 21 days. Tooth blocks were divided into five groups. Each experimental group was then medicated with 0.1 ml of TAP and no medication was added for control groups. After 21 days of incubation at 37°C, colony-forming units per milliliter (CFU/ml) were counted for each group.

Results:

Group II treated with TAP mixed with propylene glycol revealed a maximum reduction in CFU/ml, and that was followed by Group I and Group III, where TAP was mixed with 2% chlorhexidine (CHX) and 0.9% normal saline, respectively. Data were compared and analyzed using statistics software. The results were considered statistically significant for P < 0.05. There was a statistically significant difference in CFU/ml between propylene glycol and positive control group, between CHX and positive control group, between saline and positive control group.

Conclusions:

The propylene glycol group with TAP was the most effective vehicle for the elimination of E. faecalis from canals of tooth blocks, followed by 2% CHX solution as the second vehicle of choice over 0.9% normal saline.

The antibiofilm and collagen-stabilizing effects of proanthocyanidin as an auxiliary endodontic irrigant

AIM

To evaluate the antibiofilm effect of proanthocyanidin (PA) solution as an irrigant against Enterococcus faecalis (E. faecalis) and its influence on the mechanical properties and biodegradation resistance of demineralized root dentine.

METHODOLOGY

Enterococcus faecalis were introduced into human root dentine tubules by a serial centrifugation method and grown for 1 week. Dentine blocks infected with 1-week-old E. faecalis biofilms were treated with the following irrigants: sterile water (control), 2% chlorhexidine (CHX), 2% PA, 5% PA and 10% PA. After treatment, the live and dead bacteria proportions within E. faecalis biofilms were analysed using confocal laser scanning microscopy. To evaluate the biostability of fully demineralized dentine treated by the aforementioned irrigants, the elastic modulus and hydroxyproline release of human dentine incubated in collagenase solution were tested at baseline, after irrigant treatment and after biodegradation, respectively. Furthermore, the surface chemical bond of demineralized dentine collagen treated by various irrigants was characterized by X-ray photoelectron spectroscopy (XPS). Statistical analysis was performed using one-way anova and Tukey's post hoc multiple comparisons with the significance level at 5%.

RESULTS

The proportion of dead E. faecalis volume was significantly higher in the PA and CHX groups than that in the control group (P < 0.05). PA irrigation significantly increased the mechanical properties of demineralized dentine (P < 0.05), and the effect was enhanced with increasing PA concentration. CHX and PA groups had significantly less elasticity loss and hydroxyproline release (P < 0.05). The biomodification of dentine collagen by PA was verified by increased C-O/C-N peak percentage under C1s and C-O peak percentage under O1s narrow-scan XPS spectra.

CONCLUSIONS

Proanthocyanidin killed E. faecalis within biofilms and enhanced the biostability of the collagen matrix of demineralized root dentine. It might be used as an auxiliary endodontic irrigant with antibiofilm and collagen-stabilizing effects.

The effect of intracanal medicaments used in Endodontics on the dislocation resistance of two calcium silicate-based filling materials

Background

Intracanal medicaments can be used in various endodontic conditions including multiple visit endodontics after trauma or in regenerative endodontics. These medicaments should be removed from the root canal before the placement of the filling or repair material. The aim of the present study was to evaluate the effect of prior calcium hydroxide (Ca(OH)₂) and modified triple antibiotic paste (mTAP) placement on the push-out bond strength of TotalFill BC fast set putty (BC fast set putty) to root dentin when compared to mineral trioxide aggregate (MTA).

Methods

The root canals of 45 extracted mandibular premolars were prepared to a standardized internal diameter (1.5 mm). The specimens were randomly assigned to 3 groups according to the intracanal medicament used: mTAP (a mixture of metronidazole, ciprofloxacin, and cefaclor), Ca(OH)₂, and no intracanal medicament. After 1 week, the medicaments were removed, and the middle third of the roots were cut into two transverse sections (2.0 ± 0.05) (n = 90 slices). Thereafter, the specimens were divided into two subgroups (n = 45 each): MTA or BC putty. After 1 week, the push-out test was performed and failure mode was evaluated. The data were statistically analyzed using two-way ANOVA and Tukey’s post hoc.

Results

The application of the intracanal medicament did not significantly affect the bond strength of BC putty (p > .05). For MTA, the prior application of Ca(OH)₂ or mTAP significantly decreased the dislocation resistance (p < .05). Specimens in the MTA subgroups showed an almost equal number of cohesive and mixed types of failure while the majority of the specimens in the BC putty subgroups revealed the cohesive type.

Conclusions

Ca(OH)₂ and mTAP promoted lower bond strength of MTA to root dentin compared to the control group. However, the BC fast set putty bond strength to dentin was not affected by prior medication with Ca(OH)₂ or mTAP.

Pulp-Dentin Tissue Healing Response: A Discussion of Current Biomedical Approaches

Dental pulp tissue exposed to mechanical trauma or cariogenic process results in root canal and/or periapical infections, and conventionally treated with root canal procedures. The more recent regenerative endodontic procedure intends to achieve effective root canal disinfection and adequate pulp–dentin tissue regeneration; however, numerous limitations are reported. Because tooth is composed of vital soft pulp enclosed by the mineralized hard tissue in a highly organized structure, complete pulp–dentin tissue regeneration has been challenging to achieve. In consideration of the limitations and unique dental anatomy, it is important to understand the healing and repair processes through inflammatory-proliferative-remodeling phase transformations of pulp–dentin tissue. Upon cause by infectious and mechanical stimuli, the innate defense mechanism is initiated by resident pulp cells including immune cells through chemical signaling. After the expansion of infection and damage to resident pulp–dentin cells, consequent chemical signaling induces pluripotent mesenchymal stem cells (MSCs) to migrate to the injury site to perform the tissue regeneration process. Additionally, innovative biomaterials are necessary to facilitate the immune response and pulp–dentin tissue regeneration roles of MSCs. This review highlights current approaches of pulp–dentin tissue healing process and suggests potential biomedical perspective of the pulp–dentin tissue regeneration.

Antimicrobial Activity and Physicochemical Properties of Antibiotic Pastes Used In Regenerative Endodontics

Abstract: The purpose of this study was to evaluate the pH, solubility and antimicrobial action of Calcium Hydroxide Paste (CH), Double Antibiotic Paste (metronidazole+ciprofloxacin-DAP), calcium hydroxide added to DAP (CH/DAP) and Triple Antibiotic Paste (metronidazole + ciprofloxacin+minocycline-TAP). pH (n=10) were measured by pHmeter. Root canals of acrylic teeth (n=10) were filled with the above-mentioned intracanal-dressings, immersed in ultrapure water, and solubility was measured by the difference between the initial and final volume (7,15 and 30 days) by using micro-computed tomography. Enterococcus faecalis biofilm was induced on bovine dentin disc surfaces (n=20), and treated with the pastes for 7 days. Percentage bacterial viability was verified by confocal microscope, with LIVE/DEAD dye. CH and CH/DAP presented the highest pH values. Regarding solubility, after 7 days, antibiotic groups presented significant volume loss. CH and CH/DAP showed no statistical difference compared with the Control in antimicrobial action against E. faecalis biofilm. However, TAP and DAP presented a significant percentage reduction in bacterial population. Due to high solubility of the pastes, renewing antibiotic dressings every 7 days, or using the medications for this period in regeneration protocols is recommended. DAP is indicated for killing E. faecalis in biofilm because it has antimicrobial action similar to TAP. Adding Calcium Hydroxide to DAP significantly decreased its antimicrobial action. In spite of its the low solubility and high pH values, the CH paste showed a low level of antimicrobial action against E. faecalis in biofilm.

Effect of Intracanal Medicaments on Pull-Out Bond Strength of Fiber Post Cemented with a Self-Adhesive System

OBJECTIVES

 This study aimed to assess the effect of four intracanal medicaments on pull-out bond strength of fiber posts.

MATERIALS AND METHODS

 A total of 65 single-rooted, single-canal teeth were selected and decoronated. Root canals were prepared and after rinsing were randomly divided into five groups (n = 13). G₁: calcium hydroxide (CH), G_2: CH plus chlorhexidine (CH+CHX), G₃: triple antibiotic paste (TAP), G₄: double antibiotic paste (DAP) were applied in the canals in the four groups. The control group (G₅) received no medicament. After 4 weeks, the medicaments were rinsed off and the canals were filled with gutta-percha. Post space was then prepared in root canals for the placement of glass fiber posts and self-adhesive cement (Panavia F2). After cementation, they were subjected to pull-out bond strength test.

STATISTICAL ANALYSIS

 Data were statistically analyzed using one-way analysis of variance and Tukey test.Results The pull-out bond strength values were significantly different in the groups (p < 0.001). The highest values of bond strength were seen in G₂, G₁, and G₃ (359.97 ± 81.26, 333.79 ± 98.96, 309.27 ± 78.07), respectively. There was no significant difference between G₄ and G₅ (p = 0.75).

CONCLUSION

 The results showed that CH, CH+CHX, and TAP enhanced the pull-out bond strength of fiber post to root canal wall as compared to the control group.

Effect of varying durations of intracanal medicament application used in regenerative endodontic treatment on the push-out bond strength of a novel cement: NeoMTA Plus

Aim:

The aim of the present study was to evaluate the effect of varying durations of intracanal medicament application used in regenerative endodontic treatment on the push out the bond strength of a novel cement-NeoMTA Plus.

Materials and Methods:

A total of 60 extracted single-rooted maxillary anterior teeth were decoronated. Roots were instrumented uniformly until Peeso Reamer size #5 to simulate open apices. A total of 60 roots were then divided into four groups according to intracanal medicaments used (n = 15): Group 1: Triple antibiotic paste (TAP); Group 2: Double antibiotic paste (DAP); Group 3: Calcium hydroxide paste (CH); and Group 4 (control): No medicament. Samples were kept in saline solution for 2, 4, and 12 weeks, after which time five roots were selected randomly from each group, representing the samples of each time point. After removal of the medicaments, NeoMTA Plus was placed into 8 mm of the coronal third of the roots and samples were incubated. Roots were sectioned to obtain 2 discs per root (n = 10). A push-out test was used to measure the sealing efficacy of NeoMTA Plus. Data were analyzed using a one-way ANOVA followed by Tukey's pairwise comparisons.

Results:

CH, DAP, and TAP application resulted in significantly lower values of the push-out bond strength of NeoMTA Plus after 12 weeks compared to 2 weeks (P < 0.05).

No significant differences were found between the time points in the control group (P > 0.05).

DAP showed lowest push-out bond strength.

Conclusion:

CH, DAP, and TAP cause an alteration in dentinal surface properties leading to negative effect on bond strength of NeoMTA Plus. The effect is more evident in DAP and as treatment time is prolonged. The type and duration of medicament application have to be monitored to achieve a maximum therapeutic value as well as to avoid compromise on the coronal seal.

Effect of intracanal time of triple antibiotic paste on its removal from simulated immature roots using passive ultrasonic irrigation and XP-endo Finisher

Background. The aim of this study was to evaluate the effectiveness of different irrigation techniques in the removal of triple antibiotic paste (TAP), which was applied for 7, 21 or 90 days, from simulated root canals of immature teeth.

Methods. The root canal spaces of 190 maxillary canine teeth were filled with TAP and randomly divided into a control and 3 experimental groups according to the intracanal medicament period (7, 21 or 90 days). Syringe irrigation (SI), passive ultrasonic irrigation (PUI) and XP-endo Finisher (XP) were used for the removal of TAP (n=20). The amount of remaining medicament was calculated under a stereomicroscope using a 4-grade scoring system. Kruskal-Wallis H and Wilcoxon signedrank tests were used for statistical analyses (P<0.05).

Results. The mean percentage of residual TAP was significantly greater in the SI group compared to PUI and XP at all the time intervals (P<0.05). Paste removal efficacy of PUI was not affected by the intracanal time of TAP (P>0.05), whereas the efficacy of SI and XP was significantly affected (P<0.05). No significant differences were detected between PUI and XP at 7- and 21-day intervals (P>0.05); however, at 90-day interval, PUI removed significantly greater amount of TAP than XP did (P<0.05).

Conclusion. The time of the TAP in the root canal negatively affected the removal efficacy of the SI and XP-Endo Finisher; however, it did not affect the efficacy of the PUI.

Effects of the nitric oxide releasing biomimetic nanomatrix gel on pulp-dentin regeneration: Pilot study

Successful disinfection alongside complete endodontic tissue regeneration and revascularization are the most desired clinical outcomes of regenerative endodontics. Despite reported clinical successes, significant limitations to the current regenerative endodontic procedure (REP) have been elucidated. To improve the current REP, an antibiotics and nitric oxide (NO) releasing biomimetic nanomatrix gel was developed. The study evaluates antibacterial effects of an antibiotics and NO releasing biomimetic nanomatrix gel on multispecies endodontic bacteria. Antibiotics, ciprofloxacin (CF) and metronidazole (MN) were mixed and encapsulated within the NO releasing biomimetic nanomatrix gel. The gel was synthesized and self-assembled from peptide amphiphiles containing various functional groups. Antibacterial effects of the antibiotics and NO releasing biomimetic nanomatrix gel were evaluated using bacterial viability assays involving endodontic microorganisms including clinical samples. Pulp-dentin regeneration was evaluated via animal-model experiments. The antibiotics and NO releasing biomimetic nanomatrix gel demonstrated a concentration dependent antibacterial effect. In addition, NO alone demonstrated a concentration dependent antibacterial effect on endodontic microorganism. An in vivo analysis demonstrated the antibiotics and NO releasing biomimetic nanomatrix gel promoted tooth revascularization with maturation of root canals. An optimal concentration of and NO releasing nanomatrix gel is suggested for its potential as a root treatment material for REP and an appropriate protocol for human trials. Further investigation is required to obtain a larger sample size and decide upon ideal growth factor incorporation.

Evaluation of the preventive efficacy of three dentin tubule occlusion methods against discoloration caused by triple-antibiotic paste

The aim of this in vitro study was to evaluate the preventive efficacy of three dentin tubule occlusion methods against discoloration caused by triple-antibiotic paste (TAP). Sixty extracted human incisors were sectioned, and the access was opened. The specimens were randomly allocated to the following four groups (n = 15): bonding application (BD), teethmate desensitizer (TM), Nd:YAG laser application (LS), and no surface treatment (control, C). Specimens were discolored with TAP over a period of 3 weeks. The color was measured by spectrophotometry at two time-points: initially and after 3 weeks of TAP placement. Color differences (∆E) were calculated and analyzed. Discoloration was visually noticed in all teeth after 3 weeks. The differences between the control group and the three dentin tubule occlusion methods were statistically significant (p < 0.05); however, there were no statistically significant differences among the BD, TM, and LS groups (p > 0.05).

Effect of intracanal medicaments used in endodontic regeneration on the push-out bond strength of a calcium-phosphate-silicate-based cement to dentin

Objective:

To evaluate the effects of various endodontic regeneration agents on the push-out bond strength of Endosequence Root Repair Material (ERRM) to root-canal dentin.

Methods:

Fifty single-rooted human teeth were selected and instrumented to obtain a standard internal diameter of 1.5 mm. Specimens were randomly divided into four experimental groups and treated with an intracanal medicament [calcium hydroxide (CH), double antibiotic paste (DAP), triple antibiotic paste (TAP), TAP with amoxicillin (mTAP)] and a non-treated control group. Medicaments were removed after three weeks, and ERRM was applied to all specimens. The coronal portion of each root was then sliced into 2-mm-thick parallel transverse sections (2 slices per tooth, n=20 slices per group), and a push-out test was used to measure the bond strength of ERRM to dentin. Data were analyzed using Bonferroni-corrected Mann-Whitney tests, with the level of significance set at p<0.05.

Results:

The push-out bond strength of the CH group was significantly higher than that of the TAP, DAP and mTAP groups (p< 0.005). Furthermore, the bond strength of the control group was higher than the bond strength of both the DAP and mTAP groups.

Conclusion:

The use of CH in clinical practice may help improve the adhesion of ERRM to dentin.

Retention of BioAggregate and MTA as coronal plugs after intracanal medication for regenerative endodontic procedures: an ex vivo study

Objectives

This study compared the retention of BioAggregate (BA; Innovative BioCeramix) and mineral trioxide aggregate (MTA; Angelus) as coronal plugs after applying different intracanal medications (ICMs) used in regenerative endodontics.

Materials and Methods

One-hundred human maxillary central incisors were used. The canals were enlarged to a diameter of 1.7 mm. Specimens were divided into 5 groups (n = 20) according to the ICM used: calcium hydroxide (CH), 2% chlorhexidine (CHX), triple-antibiotic paste (TAP), double-antibiotic paste (DAP), and no ICM (control; CON). After 3 weeks of application, ICMs were removed and BA or MTA were placed as the plug material (n = 10). The push-out bond strength and the mode of failure were assessed. The data were analyzed using 2-way analysis of variance, the Tukey's test, and the χ² test; p values < 0.05 indicated statistical significance.

Results

The type of ICM and the type of plug material significantly affected bond strength (p < 0.01). Regardless of the type of ICM, BA showed a lower bond strength than MTA (p < 0.05). For MTA, CH showed a higher bond strength than CON, TAP and DAP; CHX showed a higher bond strength than DAP (p < 0.01). For BA, CH showed a higher bond strength than DAP (p < 0.05). The mode of failure was predominantly cohesive for BA (p < 0.05).

Conclusions

MTA may show better retention than BA. The mode of bond failure with BA can be predominantly cohesive. BA retention may be less affected by ICM type than MTA retention.

Orthodontic Movement after Regenerative Endodontic Procedure: Case Report and Long-term Observations

INTRODUCTION

Although regenerative treatment approaches in teeth with incomplete root formation and pulp necrosis have become part of the suggested therapeutic endodontic spectrum, little is known about the effect of orthodontic movement in the tissue that has been regenerated. Furthermore, as the number of adults undergoing orthodontic treatment increases, there is an increasing need to investigate the changes that these tissues may undergo during orthodontic movement. Here we describe the alterations observed after the application of orthodontic forces in a case of an apically root-fractured necrotic immature root that had been managed with regenerative endodontic procedures in the past.

METHODS

A 9-year-old male patient was referred after suffering the third incidence of trauma in the anterior maxilla. Radiographic evaluation revealed a periapical rarefaction associated with an apically root-fractured immature central incisor. Clinical evaluation revealed a buccal abscess and grade 3 tooth mobility. Periodontal probing was within normal limits. The tooth was accessed and disinfected by using apical negative pressure irrigation of 6% NaOCl. Intracanal dentin conditioning was achieved by using 17% EDTA for 5 minutes. A blood clot was induced from the periapical area, and calcium silicate-based cement was placed in direct contact with the blood clot at the same visit. The composite resin restoration was accomplished in the same appointment.

RESULTS AND CONCLUSIONS

Recall radiographic examination after 24 months revealed healing of the periapical lesion and signs of continuous root development despite the apical root fracture. Clinical evaluation revealed normal tooth development, normal mobility, and a resolving buccal infection. The tooth was subjected to orthodontic treatment because of Class II division 1 malocclusion with an overjet of 11 mm. After completion of the orthodontic treatment, 5.5 years after the initial intervention, the radiographic image revealed marked remodeling of the periapical tissues and repair of the apical fractures, and the buccal infection had resolved completely.

Efficacy of XP-Endo Finisher in the Removal of Triple Antibiotic Paste from Immature Root Canals

INTRODUCTION

The aim of this study was to evaluate and compare the effectiveness of the XP-Endo Finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland) with passive ultrasonic irrigation (PUI) and needle irrigation in the removal of triple antibiotic paste (TAP) from the straight immature root canals of extracted teeth.

METHODS

Thirty-four freshly extracted single-rooted teeth were used. All canals were prepared up to the ProTaper F5 file (Dentsply Maillefer, Ballaigues, Switzerland). Apices were drilled to simulate teeth with immature apices. The canals were filled with TAP, sealed, and incubated at 37°C and 100% humidity for 1 month. Samples were randomly assigned to 3 experimental groups according to the method used for TAP removal: XP-Endo Finisher, PUI, and needle irrigation (n = 10). Then, the roots were split into 2 halves. The amount of TAP residue in the apical portion of each segment was evaluated using a scanning electron microscopy and scored.

RESULTS

The amount of remaining TAP was significantly lower in the XP-Endo Finisher group compared with the needle irrigation and PUI groups (P < .05). Between the needle irrigation and PUI groups, there were no statistically significant differences (P > .05).

CONCLUSIONS

Within the limitations of this study, the XP-Endo Finisher removed significantly more TAP than needle irrigation and PUI.

Direct and indirect antibacterial effects of various concentrations of triple antibiotic pastes loaded in a methylcellulose system

We investigated the direct and indirect (residual) antibacterial effects of various concentrations of triple antibiotic paste (TAP) loaded into a methylcellulose system. Enterococcus faecalis (E. faecalis) was grown on sterilized dentin blocks (n = 60) and treated with clinically used TAP (1,000 mg/mL), low concentrations of methylcellulose-based TAP (100, 10, and 1 mg/mL), placebo paste, or 1.5% NaOCl (n = 10). The pastes were then removed, and biofilm disruption assays were performed. Additional dentin blocks (n = 120) were pretreated with the same experimental groups (n = 20). The pastes were rinsed off, and the samples were immersed independently in phosphate-buffered saline for 2 and 4 weeks (n = 10). E.faecalis was then grown on the dentin blocks, and biofilm disruption assays were performed. Fisher's Exact and Wilcoxon rank sum tests were used for statistical analyses. With regard to direct antibacterial effects, all treatment groups demonstrated complete eradication of biofilms in comparison to placebo paste, while 10 mg/mL of TAP or higher provided substantial residual antibacterial effects. However, dentin treated with 1 mg/mL of TAP or 1.5% NaOCl did not provide substantial residual antibacterial effects. Dentin pretreated with 10 mg/mL of TAP or higher exhibited extended residual antibacterial effects and can thus be used during endodontic regeneration.(J Oral Sci 58, 575-582, 2016).

Retreatment of failed regenerative endodontic of orthodontically treated immature permanent maxillary central incisor: a case report

A revascularization procedure was shown to be the best alternative therapy for immature teeth with necrotic pulp and apical infection. A 12 year old female with a history of trauma to her upper central incisor and a sinus tract was referred for endodontic treatment. She was an active orthodontic patient and had undergone regenerative endodontic treatment for the past 2 years. Clinical examination revealed no response to sensibility, percussion, and palpation tests. The preoperative radiograph showed an open apex and apical rarefaction. The case was diagnosed as previously treated tooth with asymptomatic apical periodontitis. Regenerative endodontic retreatment was performed, and the case was followed for 3 years. Clinical, radiographic, and cone-beam computed tomography follow-up examination revealed an asymptomatic tooth, with evidence of periapical healing and root maturation.

Tissue characterization following revascularization of immature dog teeth using different disinfection pastes

Revascularization of immature teeth with necrotic pulps traditionally involves the use of triple antibiotic paste, which may sometimes lead to undesirable complications. The objective of this study was to assess tissue repair in immature dog teeth with apical periodontitis subjected to revascularization, comparing two different pastes used for root canal disinfection. Apical periodontitis was induced in 30 dog premolars. Teeth were randomly divided into three experimental groups: root canals filled with triple antibiotic paste (n = 10); root canals filled with 1% propolis paste (n = 10); and no medication (n = 10). An additional group (n = 10, no intervention) was used as control. After 7 months, the jaws were histologically evaluated for the following variables: newly formed mineralized tissue (present/absent); vital tissue in the canal space (absent/periodontal ligament-like/pulp-like); apical extension of root (present/absent); and severity of inflammatory process (absent/mild/moderate/severe). There were no statistically significant differences among the experimental groups in new mineralized tissue formation and apical root development. The formation of vital tissue in the canal space, in turn, was statistically different between the triple paste and propolis groups: vital tissues were present in all revascularized teeth disinfected with propolis paste (100%), compared to 71% of those disinfected with the triple paste. Severity of inflammatory process was different between the triple paste and no medication groups. The new tissues formed onto canal walls and in the root canal space showed characteristics of cementum and periodontal ligament, respectively. Propolis may have some advantages over the triple paste for the revascularization of immature teeth.