In vitro evaluation of the susceptibility of endodontic pathogens to calcium hydroxide combined with different vehicles

Silver Nanoparticles Alone or in Combination with Calcium Hydroxide Modulate the Viability, Attachment, Migration, and Osteogenic Differentiation of Human Mesenchymal Stem Cells

This study aimed to evaluate the effect of silver nanoparticles (AgNPs) alone or in combination with calcium hydroxide (Ca(OH)2) on the proliferation, viability, attachment, migration, and osteogenic differentiation of human mesenchymal stem cells (hMSCs). Different concentrations of AgNPs alone or mixed with Ca(OH)2 were prepared. Cell proliferation was measured using AlamarBlue, and hMSCs attachment to dentin disks was evaluated using scanning electron microscopy. Live-dead imaging was performed to assess apoptosis. Wound healing ability was determined using the scratch-migration assay. To evaluate osteogenic differentiation, the expression of Runt-related transcription factor (RUNX2), Transforming growth factor beta-1 (TGF-β1), Alkaline Phosphatase (ALP), and Osteocalcin (OCN) were measured using real-time reverse transcriptase polymerase chain reaction. ALP staining and activity were also performed as indicators of osteogenic differentiation. AgNPs alone seemed to favor cell attachment. Lower concentrations of AgNPs enhanced cell proliferation. AgNP groups showed markedly less apoptosis. None of the medicaments had adverse effects on wound closure. The expression of TGF-β1 was significantly upregulated in all groups, and OCN was highly expressed in the AgNP groups. AgNPs 0.06% showed the most enhanced ALP gene expression levels, activity, and marked cytochemical staining. In conclusion, AgNPs positively affect hMSCs, making them a potential biomaterial for various clinical applications.

Fast self-curing α-tricalcium phosphate/β-dicalcium silicate composites beneficial for root canal sealing treatment

Objectives

α-tricalcium phosphate (α-TCP) and β-dicalcium silicate (β-C2S) have attracted much attention since these two types of self-curing Ca-phosphate and Ca-silicate are valuable biomaterials for bone defect or endodontic therapy. However, the injectable paste of their individual with high liquid/solid ratio is junior for root canal sealing due to very long self-setting time, low pH value and/or much volume shrinkage during paste-to-cement transformation.

Methods

Our studies evaluated the effect of biphasic ratio, liquid/solid ratio and pH condition of aqueous medium on setting time and mechanical strength of this biphasic composite cement, and also the hydroxyapatite re-mineralization potential and anti-microleakage level of the cements with different α-TCP/β-C2S ratio were explored in vitro. A control group free of paste filler was included in the extracted teeth model. Dentine re-mineralization and microleakage degree were observed by scanning electron microscopy and microCT reconstruction analysis.

Results

It indicated that the weak acidic solution with pH value of 6.0 may produce a significantly shorter initial setting time (from 90 min to less 20 min) and expected final setting time (<150 min) for the biphasic composite (2:1 or 1:2) in comparison with the pure β-C2S. Notably, the phasic composites exhibited limited microleakage and induced hydroxyapatite mineralization in the dentine tubules. These hydraulic pastes also produced strong alkaline feature and appreciable compressive resistance (12–18 MPa) after setting for a very short time stage. Moreover, a link between the addition of α-TCP leading to fast re-mineralization reaction was established.

Significance

Our findings suggest that the appreciable self-setting and physicochemical properties adaption to root canal sealability make α-TCP/β-C2S composites as preferential candidates for endodontic treatments.

Antibacterial Activity of Various Intracanal Medicament against Enterococcus faecalis, Streptococcus mutans and Staphylococcus aureus: An In vitro Study

Aim

The aim of this study was to evaluate and compare the antimicrobial efficacy of triple antibiotic paste (TAP), calcium hydroxide, and Odontopaste which are used as intracanal medicaments against Enterococcus faecalis, Streptococcus mutants, and Staphylococcus aureus.

Materials and Methods

Antibiotic sensitivity testing was done using agar well diffusion method of the following intracanal medicaments: Group 1: TAP (Ciprofloxacin, metronidazole, and doxycycline mixed in a ratio of 1:1:1; Group 2: Calcium hydroxide paste; Group 3: Odontopaste; Group 4: Sterile saline (0.9%) as a negative control. Each medicament was tested against E. faecalis, S. mutants, and S. aureus. The maximum zone of inhibition was noted by diameter size (mm) and analyzed with one-way ANOVA.

Results

TAP showed the highest zone of inhibition. There is no significant difference between Odontopaste and calcium hydroxide against E. faecalis and S. aureus. There is a significant difference between TAP, Odontopaste, and calcium hydroxide against S. mutants. The order of the highest zone of inhibition is TAP > Odontopaste>Calciumhydroxide.

Conclusion

With in the limitations of the study, TAP had better antibacterial activity against E. faecalis, S. mutants, and S. aureus followed by odontopaste and calcium hydroxide, Hence, Odontopaste can be used as an alternative for calcium hydroxide in the infected root canal.

Nonsurgical endodontic management of dens invaginatus: a report of two cases

Dens invaginatus is a malformation affecting mainly the superior lateral incisors. It is defined as an infolding of the crown hard tissues, including the enamel and dentin, and can extend up to the root apex. Root canal treatment of this abnormality is considered difficult due to the complex anatomy presented by these teeth. This case series presents nonsurgical endodontic treatment in two cases of dens invaginatus (type II and III) in maxillary lateral incisors. This nonsurgical or conventional endodontic treatment results in healing of the periapical lesions associated with both cases, with no need for extra intervention e.g. surgical or invasive management. The manual instrumentation associated with sodium hypochlorite and calcium hydroxide were able to completely heal the lesions.  Radiographic exams were carried out to control and asses the healing. Nonsurgical treatment was successful in both cases with adequate repair after a 6-year follow-up with radiographic and tomographic assessments.

Effect of ultrasonic streaming on intra-dentinal disinfection and penetration of calcium hydroxide paste in endodontic treatment

Objective

The antimicrobial effect of ultrasonic agitation of calcium hydroxide (CH) pastes in infected bovine dentin and their penetrability were evaluated using confocal laser scanning microscopy (CLSM) and microbiological culture.

Material and Methods

Fifty-two bovine teeth were infected with Enterococcus faecalis using a new contamination protocol; then they received CH paste and were divided into groups with or without ultrasound. Ultrasonic agitation was conducted for 1 min with a plain point insert. After 15 d, the CLSM analyzed the viable and dead bacteria with Live and Dead assay. The dentinal wall debris was collected by burs, and the colony forming units (CFU/mL) were counted. The penetrability of the paste inside dentinal tubules was tested using the B-rodamine dye.

Results

The calcium hydroxide paste showed better results with the use of ultrasonic agitation (p<0.05).

Conclusion

The ultrasonic agitation of CH paste increased its antimicrobial action and was responsible for intradentinal penetration with the fulfilment of the tubules.

Intratubular disinfection with tri-antibiotic and calcium hydroxide pastes

OBJECTIVE

The aim of this study was to compare the in vitro intradentinal antimicrobial ability of the calcium hydroxide and tri-antibiotic pastes.

MATERIALS AND METHODS

Standard bovine dentin tubes were sterilized and then infected with Enterococcus faecalis by a new contamination protocol of great depths of dentin. The specimens were filled with the medications, divided into two test-groups: calcium hydroxide (Group 1) and tri-antibiotic (Group 2) pastes. After 15 days, the teeth were evaluated by microbiological culture and confocal laser scanning microscopy (CLSM) with viability dye assay LIVE/DEAD inside dentinal tubules. In experiment of culture, the bacterial collection of the dentin fragments was done for counting the colony-forming units.

RESULTS

The tri-antibiotic paste had a slightly greater antimicrobial effect; however, there was no statistical difference between the groups.

CONCLUSIONS

It was concluded that the tri-antibiotic paste and the calcium hydroxide paste exercise the same effect on intra-tubular decontamination against E. faecalis. So, due the multiples advantages, the calcium hydroxide paste can be the choice for dentinal decontamination in regenerative procedures.

Critical Review on Eliminating Endodontic Dental Infections Using Herbal Products

The main purpose of a root canal treatment is to eliminate the bacteria and their products from the pulp space. Chemomechanical preparation (chemical-refers to irrigating solutions, i.e., either synthetic chemicals or herbal solutions and mechanical-refers to instrumentation of a root canals with endodontic files) of a root canal system plays a major role in obtaining the rationale of root canal treatment. Various synthetic chemicals known as endodontic irrigants play a major role in disinfection, but also have undesirable properties like allergic potential, toxicity, unacceptable taste, etc. Today there is a major change in trend towards the use of natural herbal medicines as a part of dental treatment due to its easy availability, less toxicity, and cost effectiveness. This article aims to provide a comprehensive review of various herbal endodontic irrigants evaluated for their effectiveness in the disinfection of a root canal system. This literature review is conducted using electronic databases "PubMed," "Google Scholar," and "Scopus," and articles were limited to those in the English language and published between 1980 and 2014.

Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer.

Efeitos da dentina sobre o pH e atividade antimicrobiana de diversas formulações com hidróxido de cálcio

Objetivo Avaliar o efeito da dentina sobre o pH e a atividade antimicrobiana de formulações com hidróxido de cálcio. Material e método O pH e a atividade antimicrobiana das formulações (G1- polietilenoglicol, G2- glicerina e paramonoclorofenol canforado ou G3- clorexidina) foram analisados nas formulações puras (G1A, G2A e G3A) ou acrescidas de dentina em pó (G1B, G2B e G3B). Tubos de polietileno foram preenchidos com uma das formulações e imersos em água destilada. O pH foi analisado após 24 horas, 7, 14 e 21 dias. A atividade antimicrobiana foi avaliada sobre Enterococcus faecalis (ATCC 29212), através do teste de difusão em ágar. Os resultados foram submetidos aos testes de ANOVA e Tukey (p=0,05). Resultado A dentina não exerceu efeito sobre o pH das formulações, exceto ocasionando a redução em G1, no período de 24 horas (p<0,05). Nas demais formulações, não houve interferência da dentina sobre o pH (p>0,05). Quando comparados entre os grupos, em 24 horas e 7 dias, G1A e G1B apresentaram menor pH (p<0,05). Em 14 dias, G2A, G2B, G3A e G3B demonstraram similar pH (p>0,05), assim como entre G3B e G1A (p>0,05). Em 21 dias, todas as formulações demonstram semelhante pH (p>0,05). Os resultados em ordem decrescente da atividade antimicrobiana foram G2A=G2B>G3A=G3B>G1A=G1B (p<0,05). Conclusão A dentina não interferiu no pH e na atividade antimicrobiana das diferentes formulações com hidróxido de cálcio, exceto na associação com o polietilenoglicol, em que ocasionou a redução do pH apenas no período de 24 horas. A formulação com paramonoclorofenol canforado apresentou maior atividade antimicrobiana, seguida da clorexidina e do polietilenoglicol.

A microleakage study of gutta-percha/AH Plus and Resilon/Real self-etch systems after different irrigation protocols

The development and maintenance of the sealing of the root canal system is the key to the success of root canal treatment. The resin-based adhesive material has the potential to reduce the microleakage of the root canal because of its adhesive properties and penetration into dentinal walls. Moreover, the irrigation protocols may have an influence on the adhesiveness of resin-based sealers to root dentin.

Antimicrobial effect of calcium hydroxide as an intracanal medicament in root canal treatment: a literature review - Part I. In vitro studies

The goal of endodontic treatment is the prevention and control of pulpal and periradicular infections. Calcium hydroxide (Ca(OH)2) has been widely used in endodontics as an intracanal medicament to eliminate the remaining microorganisms after chemomechanical preparation. The purpose of this article is to review the antimicrobial properties of Ca(OH)2 as an intracanal medicament in root canal treatment. The first part of this review details the characteristics of Ca(OH)2 and summarizes the results of in vitro studies related to its antimicrobial effect. The antimicrobial effect of Ca(OH)2 results from the release of hydroxyl ions when it comes into contact with aqueous fluids. Ca(OH)2 has a wide range of antimicrobial effects against common endodontic pathogens, but is less effective against Enterococcus faecalis and Candida albicans. The addition of vehicles or other agents might contribute to the antimicrobial effect of Ca(OH)2.

Fracture resistance of human root dentin exposed to calcium hydroxide intervisit medication at various time periods: an in vitro study

The aim of this study was to evaluate the effect of calcium hydroxide on the fracture resistance of human root dentin at different time intervals. After root canal preparation, one hundred single-rooted premolar human teeth were randomly divided into two equal groups. After placement of calcium hydroxide paste within the canal, one group of teeth was divided into 5 subgroups and incubated for a period of 1 week or 1, 3, 6, or 12 months at 37°C and 100% humidity. The second group of teeth was also divided into 5 subgroups and incubated under the same conditions without placement of calcium hydroxide paste. After mounting the teeth in a Zwick test machine, the force required to break each tooth was determined. Data analysis was performed using the one- and two-way analysis of variance tests. The results demonstrated that the mean force needed to cause fracture differed significantly between the two groups during the first, third and sixth months of incubation (P = 0.001, P < 0.001 and P = 0.035, respectively), and the amount of force necessary for fracture was greater in the control group. Therefore, it would appear from this study that using calcium hydroxide as a long-term intracanal dressing showed a significant decrease in peak load at fracture when compared with the control groups at the end of the first, third and sixth months of treatment and would suggest that using Ca(OH)2 for periods longer than 1 month should be used with caution.

In vitro susceptibility of oral Candida albicans strains to different pH levels and calcium hydroxide saturated aqueous solution

Candida albicans is present in the oral cavity and in the whole digestive tract of humans and other animals, being frequently related to endodontic treatment failure. The present study determined the incidence of C. albicans in the oral cavity and the susceptibility of isolates to different pH values and saturated calcium hydroxide aqueous solution at pH 12.5. Sixty-five patients attending the Endodontic Clinic at the Sagrado Coração University participated in the study. The collected samples were cultivated in selective media for C. albicans and the isolates were tested in terms of resistance to both alkaline pH and saturated aqueous solution of calcium hydroxide. In relation to time variables, yeast viability was assessed by the Sabouraud's agar culture and fluorescein diacetate and ethidium bromide fluorescent staining method. Results from the different pHs and experimental times, including those from different techniques measuring fungal viability, were compared using the chi-square and Fisher's exact tests (α=0.05). The yeasts became completely inviable after 48 h of contact with the calcium hydroxide solution. On the other hand, when exposed to the alkaline culture broth, the yeasts were found to be viable at pHs 9.5 and 10.5 for up to 7 days. In conclusion, C. albicans can only be completely inhibited by direct contact with saturated calcium hydroxide aqueous solution after 48 h of exposure.

Concentration of hydrogen ions in several calcium hydroxide pastes over different periods of time

The purpose of this in vitro study was to measure the concentration of hydrogen ions (pH) of calcium hydroxide [(Ca(OH)2] pastes combined with different vehicles over 7 periods of time. The Ca(OH)2 was manipulated with the following vehicles: i: sterile water; ii: iodoform plus sterile water; iii: local anesthetics (Lydocaine 2% with 1: 100,000 epinephrine); iv: polyethyleneglycol; v: glycerin; vi: 2.0% chlorhexidine gel; vii: camphorated paramonochlorophenol (CMCP); viii: (CMCP) + glycerin; and ix: polyethyleneglycol plus CMCP. The pastes were made on a glass plate to toothpaste consistency and the pH was measured at the following times: 5 min, 1, 24, 48 h; 7, 14 and 28 days. The data were statistically analyzed (Kruskal-Wallis at p<0.05). At 5 min, 1 and 24 h, the pH of all tested pastes ranged from 13.05 to 11.16. At 48 h and 7 days the pH of all tested pastes ranged from 11.66 to 8.92. At 14 and 28 days almost all pastes had pH means lower than 10. In conclusion, the mean pH of all tested calcium hydroxide pastes decreased with the time. Pastes made with aqueous vehicles (especially with sterile water), followed by oily vehicles (especially with CMCP + glycerin), held the highest pH means over the periods of time tested.

The antimicrobial effects of root canal irrigation and medication

The role of microorganisms in the development and maintenance of pulpal and periapical inflammation have been well documented. The success of root canal treatment largely depends on the elimination of microbial contamination from the root canal system. Although mechanical instrumentation of root canals can reduce bacterial population, effective elimination of bacteria cannot be achieved without the use of antimicrobial root canal irrigation and medication. This review will discuss the antimicrobial effects of the known root canal irrigants and medicaments and explore future developments in the field.