Biocompatibility of various formula root filling materials for primary teeth

Ball Milling Medium May Tune the Self-Curing Property and Root Canal Microleakage of β-Dicalcium Silicate-Based Cement

It is still a challenge to overcome the extended setting process of pure Ca-silicate as root canal fillers. We investigated the effects of attapulgite (a basic hydrous silicate of magnesium and aluminum) and ball-milling liquid medium on the self-curing properties of conventional β-dicalcium silicate (C2Si)-based cements. It was shown that a minor amount of attapulgite nanofibers (1–4%) had only a slight influence on setting time but caused a large increase in compressive resistance and structural stability. In particular, the ball milling media with different acetone/water ratios (3:0, 2:1, 1:2, 0:3) could directly influence the particle size distribution of C2Si powders, and the co-existence of liquid media (2:1 or 1:2) may be beneficial for shortening the setting time, enhancing early-stage compressive strength, and significantly improving the anti-microleakage ability of cement. Moreover, the composite cements also exhibited appreciable antibacterial efficacy in vitro. These findings demonstrated that the physicochemical properties of the Ca-silicate powders could be tuned by adding a minor amount of inorganic silicate nanofibers and a simple ball milling condition, and such a facile strategy is favorable for developing novel (pre-mixed) Ca silicate-based cements as root canal sealers.

Improvement of Biological Effects of Root-Filling Materials for Primary Teeth by Incorporating Sodium Iodide

Therapeutic iodoform (CHI₃) is commonly used as a root-filling material for primary teeth; however, the side effects of iodoform-containing materials, including early root resorption, have been reported. To overcome this problem, a water-soluble iodide (NaI)-incorporated root-filling material was developed. Calcium hydroxide, silicone oil, and NaI were incorporated in different weight proportions (30:30:X), and the resulting material was denoted DX (D5~D30), indicating the NaI content. As a control, iodoform instead of NaI was incorporated at a ratio of 30:30:30, and the material was denoted I30. The physicochemical (flow, film thickness, radiopacity, viscosity, water absorption, solubility, and ion releases) and biological (cytotoxicity, TRAP, ARS, and analysis of osteoclastic markers) properties were determined. The amount of iodine, sodium, and calcium ion releases and the pH were higher in D30 than I30, and the highest level of unknown extracted molecules was detected in I30. In the cell viability test, all groups except 100% D30 showed no cytotoxicity. In the 50% nontoxic extract, D30 showed decreased osteoclast formation compared with I30. In summary, NaI-incorporated materials showed adequate physicochemical properties and low osteoclast formation compared to their iodoform-counterpart. Thus, NaI-incorporated materials may be used as a substitute for iodoform-counterparts in root-filling materials after further (pre)clinical investigation.

Effect of Root Canal Filling Materials and Pretreatment with Solvents on the Shear Bond Strength of Composite Resin with Primary Tooth Dentin

Aim

Root canal filling materials have the tendency to inhibit adhesion of resin-based composites. This study was aimed at evaluating the effect of root canal filling materials and their solvents on the shear bond strength (SBS) of resin composite with the primary tooth dentin.

Methods and Materials

Seventy-two intact anterior primary teeth were selected. Smooth dentinal surfaces were prepared to a minimum diameter of 3 mm and thickness of 1.5–2.0 mm. The samples were equally divided into six groups (n = 12). In group 1: control group, no root filling material; in group 2: Metapex, no solvent; in group 3: Metapex+ethanol solvent; in group 4: ZOE, no solvent; in group 5: ZOE+ethanol solvent; and in group 6: ZOE+orange oil solvent were applied. Then, dentin surfaces were etched, and composite restorations were placed and cured. The specimens were stored in distilled water at 37°C for 24 hours. SBS values were determined using a universal testing machine.

Results

The SBS values of composite to dentin in groups 2 and 4 were significantly lower than those in the control group (P < 0.001). Cleansing of the specimens with 96% ethanol after removal of Metapex significantly increased the composite-dentin bond (P < 0.001). Applying ZOE, only orange oil solvent significantly increased the SBS of the composite to the primary tooth dentin (P = 0.01).

Conclusion

To reduce the negative effects of endodontic root filling materials on the SBS of composite and primary tooth dentin, ethanol is a suitable solvent when Metapex is used, while orange oil might be a better choice than ethanol when applying ZOE.

Physicochemical properties and filling capacity of an experimental iodoform-based paste in primary teeth

In this study, we evaluated the physicochemical properties (PCP; radiopacity, flow, pH, and solubility) and the quality of root canal filling provided by an experimental industrialized paste (EP), with the same active ingredients as those of the Guedes Pinto paste, compared with the Vitapex® paste. PCP were analyzed according to the ANSI/ADA laboratory testing methods for endodontic filling and sealing materials. To analyze filling capacity, 120 artificial primary teeth (60 maxillary incisors [MIs] and 60 mandibulary molars [MMs]) were endodontically treated. The teeth were divided into eight groups based on the dental group (MIs or MMs), filling material (Vitapex® or EP), and insertion method (syringe or lentulo). The Image J® software was used to analyze the initial an final digital radiographies of each tooth, measuring and comparing root canal and void areas. The percentage of filling failure areas was obtained. Data were submitted to ANOVA and Tukey test of mean comparison. Regarding PCP, both pastes presented results according the ANSI/ADA standards. Flow capacity: Vitapex: 19.6 mm, EP: 25 mm (p < 0.01); radiopacity: Vitapex: 4.47 mmAl, EP: 6.06 mmAl (p < 0.01); pH after 28 days: Vitapex: 7.79, EP: 8.19 (p = 0.12); and solubility after 28 days: Vitapex: 2.68%, EP: 2.89% (p > 0.05). Regarding filling capacity analysis, EP demonstrated 12.5% of failure against 31.5% of Vitapex (p < 0.01). Compared to Vitapex, EP presented statistically significantly better results in flow, radiopacity, pH, and filling capacity. Molars presented more filling failures than incisors. The insertion method using a syringe and a thin tip was significantly better than that using Lentulo spiral carriers.

Cytocompatibility of filling pastes by primary teeth root simulating model

Evaluate the cytocompatibility of Calen^®/ZO, Calcicur^®, Vitapex^®, Endoflas^®, and zinc oxide/eugenol-based (ZOE) root canal pastes (RCP) to human primary osteoblasts (HPO) through a simplified model for primary teeth. The model employed pipette tips filled with 0.037 g of paste, exposed to 185 µL of culture medium for 24 h (n = 6). Release of components was analysed by Proton Nuclear Magnetic Resonance Spectroscopy (¹H-NMR). HPO were exposed to conditioned media for 24 h. Cell viability was assessed by cell density and metabolic activity, and release of interleukin 6 (IL-6), vascular endothelial growth factor (VEGF) and fibroblast growth factor (bFGF) by immunological assay. Physicochemical properties and antimicrobial efficacy were also evaluated. ¹H-NMR spectra analysis showed similarity between ZOE, Endoflas^®, Calcicur^®, and Vitapex^® compared to Calen^®/ZO and positive control, which showed distinct released components. Calen^®/ZO and Calcicur^® exhibited high alkaline pH in all periods and showed similar solubility. Calen^®/ZO, ZOE, and Vitapex^® showed similar flow rate. Calen^®/ZO, Calcicur^®, and Vitapex^® did not exhibit antimicrobial efficacy. Calen^®/ZO presented cytotoxicity (p < 0.05). Pastes did not increase IL-6 release compared to control. Apart from Vitapex^®, all pastes significantly induced VEGF/bFGF release. Interactive effects among released products may affect biological response to filling pastes. Calcicur^®, ZOE, Endoflas^® and Calen^®/ZO presented good to moderate cytocompatibility, with low impact on pro-inflammatory cytokine release and induction of growth factors of interest to tissue repair. This simplified model, specific for the evaluation of the cytocompatibility of RCPs on primary teeth, suggests how these pastes might contribute to bone repair in clinical situations of apical periodontitis in children.

Volumetric Assessment of Root Canal Obturation Using 3% Nano-Chitosan versus Zinc Oxide Eugenol (ZOE) and Iodoform-Calcium Hydroxide (Metapex), in Primary Root Canals Shaped with Rotary versus Manual Methods: A Preliminary In-Vitro Spiral CT Study

Objectives:

In this study, chitosan was introduced and used as a substitute for pulpectomy obturation against conventional materials: zinc oxide eugenol (ZOE) and iodoform-calcium hydroxide (Ca(OH)₂). Efficacies of rotary versus manual instrumentations were also compared.

Materials and Methods:

This preliminary study was performed on 152 intact nonresorbed root canals of primary molars divided into rotary (n=78) versus hand-instrumentation (n=74) and into ZOE (n=53), iodoform-Ca(OH)₂ (n=50), and 3% nano-chitosan (n=49). Canals were cleaned/shaped using hand or rotary files. Canal spaces were measured using spiral computed tomography and obturated using the three materials. The percentages of obturation volume (POV) were estimated. Rotary and manual instrumentations were compared in terms of canal spaces before and after obturation. Three obturation materials were also compared regarding canal spaces after obturation (α=0.05).

Results:

Average POVs of materials were 96.54% (ZOE), 97.87% (Metapex), and 74.74% (nano-chitosan; P=0.000). POV of chitosan differed from the other two (P<0.001) but the other two were similar (P=0.896). Average POVs were 91.46% (manual) and 88.51% (rotary); the difference was not significant (P=0.322). Preobturation spaces of canals for different methods were 3.89 mm ³ (manual) and 3.26 mm ³ (rotary); the difference was significant (P=0.013). Two-way ANCOVA showed a significant effect of materials (P<0.001) but not root length (P=0.585) or shaping methods (P=0.362) on POVs.

Conclusion:

Nano-chitosan showed a considerable success rate but it still needs reformulation as it was weaker than the extremely successful commercial competitors. Rotary instrumentation can provide results similar to hand-filing in terms of POV although it might yield smaller canals.

Preference and usage of intracanal medications during endodontic treatment

Objectives:

To investigate the preferences of general dental practitioners (GDPs) and endodontists in using endodontic intra-canal medications (ICMs).

Methods:

This observational and descriptive study was conducted in 2014 in the western province of Saudi Arabia. Following ethical clearance and 2 pilot studies, a web-based questionnaire was electronically sent to 375 randomly and systematically selected GDPs and all endodontists in the western province (n=49). An accompanying e-mail explained the study’s aims and confirmed that the data yielded would remain confidential. The responses were collected, and the data was analyzed using the Chi-square test at p=0.05.

Results:

Significantly, the highest proportion of respondents (53.7%) reported disinfection of the root canals as the main function of ICMs. Calcium hydroxide (CH) was the preferred material of the majority of those who used the same ICM in all cases (85.7%). While the vast majority of all endodontists (87.5%) used CH after pulp extirpation, 48.5% of GDPs used formocresol (p<0.001). Almost 30% of those who used ICMs after pulp extirpation did not do so after cleaning and shaping of vital cases. Most endodontists used CH (62.5%) and antibiotics (37.5%) in necrotic pulp cases without apical lesions, which were significantly greater than those of GDPs who did the same (43.8% and 17.2%).

Conclusions:

Participants were aware that the main function of ICMs is disinfection of the root canal system. However, it is clear that GDPs should reduce their reliance on phenol- and formaldehyde-based medications. There was a distinct trend toward the use of ICMs, especially CH, in necrotic pulp cases.

Protein Activation in Periapical Reaction to Iodoform Containing Root Canal Sealer

OBJECTIVES

An association between root canal sealers and periapical lesions in primary dentition has been suggested, yet the chemical-protein interactions that may be involved in it have not been studied. The present study explored root sealer components' effect on periapical tissue proteins using bioinformatics tools.

STUDY DESIGN

For each chemical component of Endoflas F.S. root sealing material we identified the known and predicted target proteins, using STITCH (search tool for interactions of chemicals http://stitch.embl.de/ ). Identified target proteins were grouped into functional categories using the annotation clustering tool from DAVID, the Database for Annotation, Visualization and Integrated Discovery ( http://david.abcc.ncifcrf.gov/ ). STRING Protein-Protein Interaction network database identified associations between the proteins.

RESULTS

Sixteen proteins identified with STITCH served as input to DAVID annotation clustering tool. Only ZnO and Eugenol targeted proteins had statistically significant annotations. Gene Ontology terms of ZnO and Eugenol targeted proteins demonstrated that these proteins respond to mechanical stimulus and to oxidative stress. They highlight these proteins' role in the positive regulation of transcription, gene expression, cell proliferation and apoptosis, and their complementary role in the negative regulation of cell death.

CONCLUSION

When stimulated by Zinc Oxide, Eugenol and Calcium hydroxide, chemical-protein and subsequent protein-protein interactions result in cell proliferation in the periapical area. Our findings indicate that certain root sealers components may cause enlargement of the permanent tooth follicle. Dentists should be aware of this phenomenon and radiographically monitor root canal treated teeth until shedding.

Current trends in use of intracanal medications in dental care facilities: questionnaire-based survey on training dental hygienists at educational institutions

The success of root canal therapy is dependent not only on removal of infected pulp (pulpectomy) followed by root canal enlargement, but also on the pharmacological effects of intracanal medications. Various intracanal medications are used. Formaldehyde preparations such as formocresol were common in the past, but these are no longer used in Europe or the US due to the biological toxicity of formaldehyde. In this study, a questionnaire was used to determine current trends in the use of intracanal medications at dental care facilities where dental hygiene students undergo practical training. The questionnaire comprised questions regarding the types of frequently used intracanal medications and their methods of application at dental care facilities in Saitama and Shizuoka prefectures. The results indicated that calcium hydroxide preparations were more commonly used in Europe or the US. However, these results also revealed that formaldehyde preparations were frequently used, which slightly differs from the scenario in Europe and the US. This study revealed that multiple intracanal medications were used for root canal therapy. Furthermore, it was also observed that cotton plugs were generally used as applicator tips for intracanal medications, whereas the use of absorbent paper points was relatively uncommon. The results suggest that the cost of absorbent paper points needs to be reduced.

Sutures coated with antiseptic pomade to prevent bacterial colonization: a randomized clinical trial

OBJECTIVE

The aim of this study was to assess if an antiseptic pomade could reduce the bacterial colonization on multifilament sutures.

STUDY DESIGN

A randomized clinical trial was conducted with 40 volunteer patients of both sexes aged 18-70, randomly separated into experimental (n = 20) and control (n = 20) groups. The experimental group received pomade-coated sutures (iodoform + calendula) and the control group uncoated sutures. Two millimeters of the suture was harvested from each patient from the 1st to the 15th postoperative day. The bacteria that had adhered to them were cultured. The number of colony-forming units per milliliter (CFU/mL) was determined and the groups were compared using the Mann-Whitney statistical test (P < .05).

RESULTS

The experimental group showed a significant reduction in bacterial growth compared with the control group (P = .002).

CONCLUSIONS

In this experimental model, the antiseptic pomade was effective in reducing bacterial colonization on silk braided sutures.

Histological evaluation of bone response to pediatric endodontic pastes: an experimental study in guinea pig

This study aimed to evaluate by the intra-osseous implant technique the most commonly used materials for pulp therapy in pediatric dentistry: calcium hydroxide (CH), Guedes Pinto paste and CTZ paste, according to FDI (1980) and ANSI/ADA (1982) recommendations. Thirty guinea pigs, 10 for each material, divided into experimental periods of 4 and 12 weeks received one implant on each side of the lower jaw symphysis. The external lateral tube wall served as control for the technique. At the end of the observation periods, the animals were euthanized and specimens were prepared for routine histological examination. It was observed that CH and CTZ paste induced severe inflammation, a large amount of necrotic tissue, lymphocytes, foreign body cells and bone resorption, while Guedes Pinto Paste induced little or no inflammation in the 4-week observation period. After 12 weeks, the reactions to CH and Guedes Pinto paste were also absent/mild, presenting a general pattern of replacement by recently formed bone tissue while a moderate to severe inflammatory response was observed with CTZ paste. Guedes Pinto paste presented acceptable biocompatibility levels in both analyzed periods; CH only showed acceptable biocompatibility in the 12-week period while CTZ paste showed no biocompatibility in both periods. Among the tested materials, only Guedes Pinto paste presented an acceptable biocompatibility.

Low-level diode laser therapy reduces lipopolysaccharide (LPS)-induced bone cell inflammation

In this study, the aim is to investigate the cytologic effects of inflammatory bone cells after in vitro low-level laser therapy (LLLT). A human osteosarcoma cell line (MG63) was cultured, infected with lipopolysaccharide (LPS) and exposed to low-level laser treatment at 5 or 10 J/cm(2) using a 920 nm diode laser. MG63 cell attachment was observed under a microscope, and cell viability was quantified by mitochondrial colorimetric assay (MTT). LPS-treated MG63 cells were irradiated with LLLT, and the inflammatory markers iNOS, TNF-α and IL-1, were analyzed by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. The data were collected and analyzed by one-way analysis of variance (ANOVA); p < 0.05 indicated a statistically significant difference. Low-level laser treatment on MG63 cells increased their ability to attach and survive. After irradiation, the expression levels of iNOS, TNF-α and IL-1 in LPS-infected MG63 cells decreased over time (p < 0.05).

CONCLUSIONS

low-level diode laser treatment increased the MG63 cell proliferative ability and decreased the expression of inflammatory mediators in MG63 cells.

Clinical evaluation of 3Mix and Vitapex as treatment options for pulpally involved primary molars

OBJECTIVE

The aim of this study was to compare the clinical and radiographic success of 3Mix and Vitapex((R)) for root canal treatment of pulpally involved primary molars.

METHODS

Fifty teeth from 37 healthy children aged 3-8 years with pulpally involved primary molars needing root canal procedures were treated with 3Mix or Vitapex((R)) before restoration with stainless steel crowns. The research employed a prospective single-blinded randomized design. The subjects were followed up clinically and radiographically at 6 and 12 months, respectively. The outcome was compared using a Z-test with a significance level of 0.05.

RESULTS

Both groups showed 100% and 96% clinical success at 6 and 12 months, respectively. At 6 months, radiographic success of 3Mix and Vitapex((R)) was 84% and 80%, respectively, and at 12 months, radiographic success of 3Mix and Vitapex((R)) was 76% and 56%, respectively. Considering the radiographic findings at the end of 6 and 12 months, no statistically significant differences were found between the two groups (P = 0.356 and 0.068, respectively).

CONCLUSION

3Mix and Vitapex((R)) can be used as a root canal treatment agent in pulpally involved primary teeth.