Endodontic biofilm, technology and pulpal regenerative therapy: where do we go from here?

Discoloration after revascularization using calcium phosphosilicate-based bioceramic versus mineral trioxide aggregate in necrotic immature permanent anterior teeth: A Randomized clinical trial

Aim

The aim of the current study is to evaluate the effect of calcium phophosilicate-based bioceramic "Totalfill bioceramic putty" and white mineral trioxide aggregate (WMTA) as the coronal plug on discoloration after revascularization of necrotic immature permanent anterior teeth.

Materials and Methods

This study was conducted on (48) necrotic young permanent central incisors in children ranging from 8 to 14 years old, that were randomly allocated to either Totalfill bioceramic (Group I = 24) or WMTA (Group II = 24) as the coronal plug. Two visits revascularization protocol was adopted in this study using 1.5% sodium hypochlorite, followed by 17% ethylenediaminetetraacetic acid, and ending with a saline flush as irrigation solution. The double antibiotic paste was used as intracanal medication. The blood clot was used as scaffold followed by the application of collagen membrane followed by coronal plud malterial. Finally, the access was sealed using resin composite restoration and composite restoration. Clinical assessment was conducted at 1, 3, 6, 9, and 12 months, while radiographic assessment was conducted at 6 and 12 months. Data were statistically analyzed using the Chi-squared test for intergroup comparisons and Cochran's Q test for intragroup comparison.

Results

Clinically, Group I exhibited a success rate of 100%, whereas Group II exhibited a success rate of 85.7%. Radiographically, both materials showed a 90.5% success rate. There was no statistically significant difference between both materials for all assessed clinical and radiographic parameters at different follow-up periods.

Conclusions

Both Totalfill bioceramic putty and WMTA can be used successfully as coronal plug in esthetic areas.

Progress of Research on the Application of Triple Antibiotic Paste and Hydrogel Scaffold Materials in Endodontic Revascularization: A Systematic Review

Objective

To evaluate the application of hydrogel scaffold materials and triple antibiotic paste in endodontic regeneration through literature review.

Methods

An electronic search of the literature published on PubMed, Wangfang database, and CNKI database using the search terms “endodontic regeneration,” “pulp blood flow reconstruction,” “recanalization,” “triple antibiotic paste,” and “scaffold material” was conducted. The searched literature was used for analysis. Results and Conclusion. Hydrogels regulate stem cell fates, modulate growth factor release, and encapsulate antibacterial and anti-inflammatory drugs. The triple antibiotic paste is composed of metronidazole, ciprofloxacin, and minocycline, which exhibits promising antibacterial effects and duration at appropriate concentrations, with low cytotoxicity, and effectively promotes the preservation and regeneration of pulp tissues and the formation of dental hard tissues. However, issues such as tooth discoloration and bacterial drug resistance also exist. The present article reviews the progress of research on the application of hydrogel scaffold materials and triple antibiotic paste in endodontic revascularization.

Disruption of Enterococcus Faecalis biofilms using individual and plasma polymer encapsulated D-amino acids

OBJECTIVE

Our aim was to assess the anti-biofilm ability of previously unverified individual D-amino acids (DAAs), to produce plasma polymer encapsulated DAAs (PPEDAAs), to measure the shell thickness and subsequent release of DAAs, and to assess the effects of PPEDAAs on Enterococcus faecalis biofilms.

MATERIALS AND METHODS

Microtitre tray assays were used to evaluate the effect of individual DAAs (D-leucine, D-methionine, D-tryptophan, and D-tyrosine) on E. faecalis biofilms of different maturity. A mixture and individual DAAs were encapsulated with a plasma polymer for 10, 20, 40, and 60 min. The shell thickness of PPEDAAs was analyzed by ultra-high-resolution scanning electron microscopy. The release of DAAs from the PPEDAAs encapsulated for 60 min was measured over 7 days using high-performance liquid chromatography. Static biofilms were used to assess the effect of PPEDAAs on E. faecalis biofilms.

RESULTS

Individual DAAs reduced biofilm formation to various degrees, according to the DAA and the experimental times. The shell thicknesses of the PPEDAAs ranged between 31 and 76 nm and increased with encapsulation time. Diffusion of DAAs from the PPEDAAs occurred over 60 min for encapsulated D-leucine, D-methionine, and D-tyrosine and up to 7 days for D-tryptophan. PPEDAAs disrupted biofilms at every experimental time.

CONCLUSIONS

PPEDAAs of various shell thickness can be produced with the proposed methodology, DAAs are subsequently released, and the anti-biofilm activity remains unaltered.

CLINICAL RELEVANCE

Individual DAAs and PPEDAAs have anti-biofilm ability and can be considered as part of a biological strategy in endodontics.

Clinical and Radiographic Outcomes of Immature Teeth Treated with Different Treatment Protocols of Regenerative Endodontic Procedures: A Retrospective Cohort Study

Regenerative endodontic procedure (REP) is a progressive treatment modality for immature permanent teeth with necrotic pulp. The ambiguousness about the predictability of REP outcome in relation to complete disinfection of the root canal system and the occurrence of discoloration still exists. The aim of this retrospective study was to analyze two treatment protocols on clinical success rate, radiographic root development and the occurrence of discoloration. Eighteen patients were treated by a single operator by either treatment protocol according to the American Association of Endodontists (AAEP, n = 9) or a modified protocol (MP, n = 9) with the use of 5% sodium hypochlorite and sandblasting. Patients were followed up after 3, 6, 9, 12, 18 and 24 months and clinical success, radiographic root development and the occurrence of discoloration were assessed. The clinical success of MP was significantly higher in two years follow-up (p = 0.015), but the change in radiographic root area was higher for AAEP (p = 0.017) and the occurrence of discoloration was higher in AAEP (p = 0.029). The use of 5% sodium hypochlorite for a longer period of time leads to a higher success rate. The sandblasting of the access cavity reduces the occurrence of discoloration.

Combined Effect of Melittin and DNase on Enterococcus faecalis Biofilms and Its Susceptibility to Sodium Hypochlorite

Biofilm communities are tolerant to antimicrobials and difficult to eradicate. This study aimed to investigate the effect of melittin, an antimicrobial peptide, either alone or in combination with deoxyribonuclease (DNase), an inhibitor of extracellular deoxyribonucleic acid (eDNA), against Enterococcus faecalis (E. faecalis) biofilms, and biofilm susceptibility to sodium hypochlorite (NaOCl). Biofilms of E. faecalis were developed in root canals of bovine teeth. The biofilms were treated with distilled water (control), melittin, DNase, or DNase+melittin. The antibiofilm effects of the treatments were analyzed using colony forming unit (CFU) assay, crystal violet staining, confocal laser scanning microscopy (CLSM), and field emission scanning electron microscope (FE-SEM). The susceptibility of DNase+melittin-treated biofilms to NaOCl (0%, 2.5% and 5%) was investigated by the CFU assay. The data were statistically analyzed using one-way analysis of variance, followed by Tukey's test. A p-value of <0.05 was considered significant. Specimens treated with DNase+melittin showed a more significant decrease in the CFUs, eDNA level, and biofilm formation rate than those treated only with melittin or DNase (p < 0.05). CLSM analysis showed DNase+melittin treatment significantly reduced the volume of biofilms and extracellular polymeric substance compared to either treatment alone (p < 0.05). FE-SEM images showed a high degree of biofilm disruption in specimens that received DNase+melittin. 2.5% NaOCl in specimens pretreated with DNase+melittin showed higher antibacterial activity than those treated only with 5% NaOCl (p < 0.05). This study highlighted that DNase improved the antibiofilm effects of melittin. Moreover, DNase+melittin treatment increased the susceptibility of biofilms to NaOCl. Thus, the complex could be a clinical strategy for safer use of NaOCl by reducing the concentration.

Pulp regeneration with hemostatic matrices as a scaffold in an immature tooth minipig model

Control of blood clotting in root canal systems is one of the most critical and difficult concerns for regenerative endodontics therapy (RET). The purpose of this study was to investigate the effects of using gelatin- and fibrin-based hemostatic hydrogels as a scaffold on pulp regeneration in a minipig model. Cell viability of human dental pulp stem cells cultured three-dimensionally in gelatin-based and fibrin-based scaffolds was evaluated by MTT and live/dead assay. RET was performed on 24 immature premolars with an autologous blood clot (PC), gelatin-based and fibrin-based hemostatic matrices (GM and FM), or without the insertion of a scaffold (NC). The follow-up period was 12 weeks. Radiographic and histologic assessments for pulp regeneration were performed. Gelatin-based scaffolds exhibited significantly higher cell viability than fibrin-based scaffolds after 15 days (P < 0.05). The PC and GM groups showed favorable root development without inflammation and newly mineralized tissue deposited in the root canal system, while FM group presented inflammatory changes with the continuation of root development. The NC group exhibited internal root resorption with periapical lesions. The application of GM in RET led to favorable clinical outcomes of root development without inflammatory changes compared to conventional RET. Our results suggest that GM may serve as a viable regenerative scaffold for pulp regeneration.

Retreatment of failed revascularization/revitalization of immature permanent tooth - A case report

The aim of this article is to describe the clinical case of the non-surgical retreatment of a failed revascularization/revitalization treatment (RRT). The retreatment was preceded by two sessions including an interim medication with calcium hydroxide and a modified irrigation protocol containing a highly-concentrated sodium hypochlorite and prolonged usage of ethylenediaminetetraacetic acid (EDTA) to reverse unacceptable side effects of hypochlorite. During a 15- month follow-up, the healing of the periapical lesion, increased thickening of root canal walls and maturation of root was apparent. The repeated RRT represents a possible treatment modality for s failed RRT. Key words:Retreatment, revascularization, revitalization, maturogenesis, immature tooth.

Alkaline Materials and Regenerative Endodontics: A Review

Periapical health is the primary goal of endodontic treatment in mature and immature teeth. In addition, the goals of treatment of immature teeth with arrested root development include root growth to length and maturation of the apex, as well as thickening of the canal wall. These goals are valid for immature teeth that have been subjected to trauma and dental caries or that are the result of developmental anomalies that expose the tooth to the risk of pulp necrosis and consequently result in the cessation of root maturation. Regenerative endodontic procedures (REPs) have been described as a “paradigm shift” in the treatment of immature teeth with pulp necrosis and underdeveloped roots, as there is the potential for further root maturation and return of vitality. Treatment with REPs is advocated as the treatment of choice for immature teeth with pulp necrosis. REP protocols involve the use of alkaline biomaterials, primarily sodium hypochlorite, calcium hydroxide, mineral trioxide aggregates and Biodentine, and are the essential components of a successful treatment regimen.

Antibiotic abuse during endodontic treatment in private dental centers

OBJECTIVES

We evaluated antibiotic prescription practices during root canal treatments among general dentists in private dental clinics in Al-Madinah Al Munawarah, Saudi Arabia. Methods: A self-administered, questionnaire about antibiotic used during root canal treatment was distributed to 75 randomly selected general dental practitioners working in private dental clinics in Al-Madinah Al-Munawarah, Saudi Arabia, between March and April 2016. The questionnaires were collected one week later. To compare results of the collected data, Chi-square test was used.  Results: The results revealed that 60% of the dentists prescribed amoxicillin with clavulanic acid as the first choice treatment for endodontic pathosis. Clindamycin (51.6%) was the first choice for patients who were allergic to penicillin. Forty-five percent of the general practitioners prescribed antibiotics for 5 days. Approximately 83.3% of general practitioners prescribed antibiotics for acute apical abscesses. Prophylactic antibiotics were prescribed for cases with a history of infective endocarditis (65.5%), non-controlled diabetes (60.3%), placement of a prosthetic joint in the previous 2 years (46.6%), congenital heart disease (36.2%), and kidney dialysis shunts (34.5%). Conclusion: This study reveals antibiotic abuse in endodontic treatment practice in private dental clinics in Al-Madinah Al Munawarah, Saudi Arabia. General dental practitioners are lacking knowledge regarding the prescription of antibiotics in endodontic  treatment and situations requiring prophylactic antibiotics.

D-amino acids reduce Enterococcus faecalis biofilms in vitro and in the presence of antimicrobials used for root canal treatment

Enterococcus faecalis is the most frequent species present in post-treatment disease and plays a significant role in persistent periapical infections following root canal treatment. Its ability to persist in stressful environments is inter alia, due to its ability to form biofilms. The presence of certain D-amino acids (DAAs) has previously been shown to reduce formation of Bacillus subtilis biofilms. The aims of this investigation were to determine if DAAs disrupt biofilms in early and late growth stages for clinical E. faecalis strains and to test their efficacy in disrupting E. faecalis biofilms grown in sub-minimum inhibitory concentrations of commonly used endodontic biocides. From thirty-seven E. faecalis strains, the ten "best" biofilm producers were used to test the ability of a mixture containing D-leucine, D-methionine, D-tyrosine and D-tryptophan to reduce biofilm growth over a period of 24, 72 and 144 hours and when compared to their cognate L-Amino Acids (LAAs). We have previously shown that sub-MIC levels of tetracycline and sodium hypochlorite promotes biofilm growth in clinical strains of E. faecalis. DAAs were therefore tested for their effectiveness to reduce biofilm growth in the presence of sub-minimal concentrations of sodium hypochlorite (NaOCl-0.031%) and Odontocide™ (0.25% w/v), and in the presence of Odontopaste™ (0.25% w/v). DAAs significantly reduced biofilm formation for all strains tested in vitro, while DAAs significantly reduced biofilm formation compared to LAAs. The inhibitory effect of DAAs on biofilm formation was concentration dependent. DAAs were also shown to be effective in reducing E. faecalis biofilms in the presence of Odontopaste™ and sub-MIC levels of NaOCl and Odontocide™. The results suggest that the inclusion of DAAs into current endodontic procedures may reduce E. faecalis biofilms.

Root Canal Filling after Revascularization/Revitalization

INTRODUCTION

Revascularization/revitalization therapy is considered an alternative procedure for management of teeth with an immature apex and necrotic pulp, mainly when root development is interrupted in the early phases of formation. However, this clinical treatment protocol should be considered a permanent procedure?

METHOD

A maxillary central incisor with a previous and successful RR treatment was intentionally filled with a biocompatible material with the periapical tissues due to the patient's lack of adherence to the follow-up protocol.

RESULTS

The 20-month follow-up showed absence of clinical, radiological and tomographic signs and symptoms of an endodontic re-infection.

CONCLUSION

This case demonstrates that once the increased thickening of the canal walls, incrementing the root length, apical closure and the total resolution of the apical lesion are observed, the main canal of a previously treated tooth with an RR procedure can be filled.

Management of incompletely developed teeth requiring root canal treatment

Endodontic management of the permanent immature tooth continues to be a challenge for both clinicians and researchers. Clinical concerns are primarily related to achieving adequate levels of disinfection as 'aggressive' instrumentation is contraindicated and hence there exists a much greater reliance on endodontic irrigants and medicaments. The open apex has also presented obturation difficulties, notably in controlling length. Long-term apexification procedures with calcium hydroxide have proven to be successful in retaining many of these immature infected teeth but due to their thin dentinal walls and perceived problems associated with long-term placement of calcium hydroxide, they have been found to be prone to cervical fracture and subsequent tooth loss. In recent years there has developed an increasing interest in the possibility of 'regenerating' pulp tissue in an infected immature tooth. It is apparent that although the philosophy and hope of 'regeneration' is commendable, recent histologic studies appear to suggest that the calcified material deposited on the canal wall is bone/cementum rather than dentine, hence the absence of pulp tissue with or without an odontoblast layer.