Retrograde approaches in endodontic therapy

The Safety of Removing Fractured Nickel-Titanium Files in Root Canals Using a Nd: YAP Laser

The fracture of nickel-titanium (Ni-Ti) instruments during root canal instrumentation leads to compromised outcomes in endodontic treatments. Despite the significant impact of instrument facture during a root canal treatment, there is still no universally accepted method to address this complication. Several previous studies have shown the ability of a Neodymium: Yttrium-Aluminum-Perovskite (Nd: YAP) laser to cut endodontic files. This study aims to determine safe irradiation conditions for a clinical procedure involving the use of a Neodymium: Yttrium-Aluminum-Perovskite (Nd: YAP) laser for removing fractured nickel-titanium files in root canals. A total of 54 extracted permanent human teeth (n = 54) were used. This study involved nine distinct groups, each employing different irradiation conditions. Groups 1 s, 3 s, 5 s, 10 s, and 15 s simply consist of irradiation for 1, 3, 5, 10, and 15 s, respectively. After identifying the longest and safest duration time, four additional groups were proposed (labeled A, B, C, and D). Group A was composed of three series of irradiations of 5 s each separated by a rest time of 30 s (L5s + 30 s RT). Group B consisted of three series of irradiations of 5 s each separated by a rest time of 60 s (L5s + 60 s RT). Group C consisted of two series of irradiations of 5 s each separated by a rest time of 30 s (L5s + 30 s RT), and group D consisted of two series of irradiations of 5 s each separated by a rest time of 5 s (L5s + 5 s RT). In all groups, during the rest time, continuous irrigation with 2.5 mL of sodium hypochlorite (3% NaOCl) was carried out. The variation in temperature during irradiation was registered with a thermocouple during irradiation with different protocols. The mean and standard deviation of the temperature increase was noted. The calculation of the temperature was made as the Δ of the highest recorded temperature at the root surface minus (-) that recorded at baseline (37°). Additionally, scanning electron microscopy (SEM) was used after irradiation in all groups in order to assess the morphological changes in the root dentinal walls. The Nd: YAP laser irradiation parameters were a power of 3W, an energy of 300 mJ per pulse, a fiber diameter of 200 µm, a pulsed mode of irradiation with a frequency of 10 Hz, a pulse duration of 150 µs, and an energy density of 955.41 J/cm2. Our results show that the safest protocol for bypassing and/or removing broken instruments involves three series of irradiation of 5 s each with a rest time of 30 s between each series. Furthermore, our results suggest that continuous irradiation for 10 s or more may be harmful for periodontal tissue.

Cytotoxicity, Differentiation, and Biocompatibility of Root-End Filling: A Comprehensive Study

Assessing the biocompatibility of endodontic root-end filling materials through cell line responses is both essential and of utmost importance. This study aimed to the cytotoxicity of the type of cell death through apoptosis and autophagy, and odontoblast cell-like differentiation effects of MTA, zinc oxide-eugenol, and two experimental Portland cements modified with bismuth (Portland Bi) and barium (Portland Ba) on primary cell cultures. Material and methods: The cells corresponded to human periodontal ligament and gingival fibroblasts (HPLF, HGF), human pulp cells (HPC), and human squamous carcinoma cells from three different patients (HSC-2, -3, -4). The cements were inoculcated in different concentrations for cytotoxicity evaluation, DNA fragmentation in electrophoresis, apoptosis caspase activation, and autophagy antigen reaction, odontoblast-like cells were differentiated and tested for mineral deposition. The data were subject to a non-parametric test. Results: All cements caused a dose-dependent reduction in cell viability. Contact with zinc oxide-eugenol induced neither DNA fragmentation nor apoptotic caspase-3 activation and autophagy inhibitors (3-methyladenine, bafilomycin). Portland Bi accelerated significantly (p < 0.05) the differentiation of odontoblast-like cells. Within the limitation of this study, it was concluded that Portland cement with bismuth exhibits cytocompatibility and promotes odontoblast-like cell differentiation. This research contributes valuable insights into biocompatibility, suggesting its potential use in endodontic repair and biomimetic remineralization.

Present Status and Future Directions - Surgical Endodontics

Endodontic surgery encompasses several procedures for the treatment of teeth with a history of failed root canal treatment, such as root-end surgery, crown- and root resections, surgical perforation repair, and intentional replantation. Endodontic microsurgery is the evolution of the traditional apicoectomy techniques and incorporates high magnification, ultrasonic root-end preparation and root-end filling with biocompatible filling materials. Modern endodontic surgery uses the dental operating microscope, incorporates cone-beam computed tomography (CBCT) for preoperative diagnosis and treatment planning, and has adopted piezoelectric approaches to osteotomy and root manipulation. Crown- and root resection techniques have benefitted from the same technological advances. This review focuses on the current state of root-end surgery by comparing the techniques and materials applied during endodontic microsurgery to the most widely used earlier methods and materials. The most recent additions to the clinical protocol and technical improvements are discussed, and an outlook on future directions is given. While non-surgical retreatment remains the first choice to address most cases with a history of endodontic failure, modern endodontic microsurgery has become a predictable and minimally invasive alternative for the retention of natural teeth.

Evaluation of the cytotoxic effects of a new Harvard MTA compared to MTA Flow and ProRoot MTA on human gingival fibroblasts

Background

Biocompatibility is an essential property for any dental root repair material that may interact with the surrounding periodontal tissues. We hypothesise that the three mineral trioxide aggregate (MTA) restorative brands ProRoot MTA, MTA Flow and Harvard MTA have similar biocompatibility. To test this hypothesis, we compared the cytotoxic effects of these materials on human gingival fibroblast (GF).

Methods

MTA cements were prepared, and after completion of setting, they were incubated in Dulbecco's Modified Eagle Medium for 1 day or 4 days to obtain low and high concentrations of MTA elutes respectively. The elutes of MTA supplemented with fetal bovine serum were added to GF and incubated for 3 days at 37 °C and 5% CO2. Untreated cells were used as control. The cell viability was assessed using a 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay at 24, 48 and 72 h.

Results

After 24 h, the MTT assay showed that both 1- and 4-day elutes of MTA flow and Harvard MTA reduced cell viability significantly compared to control (P < 0.05). After 48 h, the 1-day elute of ProRoot MTA induced GF proliferation (P = 0.0136) while MTA flow and Harvard MTA were similar to control. After 72 h, the 1-day elute of ProRoot MTA and Harvard MTA induced GF proliferation, while the elute of MTA flow was comparable to control. The 4-day elute of Harvard MTA continued to be cytotoxic to GF after 24 h, 48 h, and 72 h incubation, while the 4-day elute of ProRoot MTA and MTA flow were similar to control.

Conclusion

ProRoot MTA and MTA Flow showed comparable biocompatibility. However, the 4-day elute of Harvard MTA was cytotoxic to GF. Further studied are required to assess the cell viability after direct contact with these materials versus eluent in vitro and compare these sealers in the clinical setting.

The use of Bioceramics as root-end filling materials in periradicular surgery: A literature review

Introduction

Periradicular surgery involves the placement of a root-end filling following root-end resection, to provide an apical seal to the root canal system. Historically several materials have been used in order to achieve this seal. Recently a class of materials known as Bioceramics have been adopted. The aim of this article is to provide a review of the outcomes of periradicular surgery when Bioceramic root-end filling materials are used on human permanent teeth in comparison to "traditional" materials.

Methods & results

An electronic literature search was performed in the databases of Web of Science, PubMed and Google Scholar, between 2006 and 2017, to collect clinical studies where Bioceramic materials were utilised as retrograde filling materials, and to compare such materials with traditional materials. In this search, 1 systematic review and 14 clinical studies were identified. Of these, 8 reported the success rates of retrograde Bioceramics, and 6 compared treatment outcomes of mineral trioxide aggregate (MTA) and traditional cements when used as root-end filling materials.

Conclusion

Bioceramic root-end filling materials are shown to have success rates of 86.4-95.6% (over 1-5 years). Bioceramics has significantly higher success rates than amalgam, but they were statistically similar to intermediate restorative material (IRM) and Super ethoxybenzoic acid (Super EBA) when used as retrograde filling materials in apical surgery. However, it seems that the high success rates were not solely attributable to the type of the root-end filling materials. The surgical/microsurgical techniques and tooth prognostic factors may significantly affect treatment outcome.

Comparative evaluation of the apical sealing ability of a ceramic based sealer and MTA as root-end filling materials - An in-vitro study

Background

The present study was aimed to evaluate and compare the apical sealing ability of two endodontic root-end filling materials namely, iRoot SP (ceramic based) and ProRoot MTA using the bacterial leakage system.

Material and Methods

A total of fifty recently extracted, single rooted teeth with a single straight canal were selected for the study. The teeth were chemo mechanically prepared. The apical 3mm of the root was resected and root end cavities were prepared. The teeth were randomly divided into two groups of twenty teeth each for the experimental root end filling materials namely, iRoot SP and ProRoot MTA. A two-chamber model was constructed using pippeter tips and plastic vials. The pipetter tips with the teeth were suspended in these caps and the entire assembly was reattached to the vial. The upper chamber was seeded withEnterococcus faecalis. An Enterococci-selective broth was used in the lower chamber. Leakage was assessed for 90 days and compared using survival statistics.

Results

The ProRoot MTA filled root end samples leaked within 30-72 days. The iRoot SP filled root end samples leaked within 51-69 days.

Conclusions

Under the parameters of this study, it can be concluded that all the tested materials showed significant apical sealing ability as root-end filling materials over a period of 90 days. iRoot SP exhibited the most effective apical sealing ability as compared to ProRoot MTA.

Key words:Apical sealing ability, Bacterial leakage, iRoot SP, ProRoot MTA, Root-end filling.

Surgical Endodontics in Dogs: A Review

Surgical endodontic therapy (apical surgery) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal. These procedures are performed through a trans-osseous approach. Terminology pertinent to this article include: apical (periapical) curettage – a surgical procedure to remove diseased tissue from the alveolar bone in the apical region of a pulpless tooth; apical cyst – a cyst in bone at the apex of a pulpless tooth. It is believed that such cysts arise after the death of the pulp from noxious physical, chemical, or bacterial stimulation of epithelial rests of Malassez; apicoectomy (apical resection) – amputation of the apical portion of the root and removal of soft tissue in the bone; epithelial rests of Malassez – cords, strands, or clusters of ectodermal cells in the periodontal ligament (or sometimes alveolar bone) derived from remnants of Hertwig's epithelial root sheath. These cells frequently begin proliferating when inflammation occurs in the periodontal ligament and are believed to be responsible for the genesis of the epithelial lining of apical cysts.

The setting mechanism of mineral trioxide aggregate

Mineral trioxide aggregate (MTA) is a powder containing calcium silicate composed of hydrophilic particles which harden at the presence of moisture. MTA was initially introduced as a root end filling material. Due its practical advantages that include superior biocompatility, effective sealing capability, and the ability to improve regeneration of the pulp and peripheral root tissues, it is used in different clinical applications such as pulp capping, apexification, pulpotomy and perforation. Despite being a promising material in endodontic treatment, MTA is not commonly used. Long setting time is the main clinical disadvantage of MTA. The aim of this review is to provide an overview of the current literature concerning the setting mechanism of MTA, accelerators and devices used to evaluate various steps of the hardening process.

Multidisciplinary Treatment of a Fenestration-type Defect

The case report aimed at treating a fenestration-type defect with multidisciplinary conventional and advanced surgical techniques. Fenestrations are isolated areas in which the exposed root surface is covered only by the periosteum and gingiva, but the remaining cortical bone remains intact. Root coverage is indicated in cases of root hypersensitivity, treatment of shallow caries lesions, cervical abrasions, and esthetic and cosmetic needs. In this case report, after proper hygiene instruction and dental biofilm control, a fenestration-type defect was treated using guided tissue regeneration (anorganic bovine matrix and resorbable membrane) and a connective tissue grafts, associated to an endodontic apicoectomy. After reevaluation, the remaining gingival recession was treated with a second gingival connective tissue graft covered with q double papillae type in order to reconstruct the periodontal tissues of the involved tooth. In this clinical case, the interaction between the different areas of dentistry has made it possible to correct a fenestration-type defect, following procedures based on scientific evidence, restoring periodontal health, esthetics, self-esteem, and meeting the patient's expectations regarding her initial complaint. This case report shows the important role of interdisciplinary approach to treating a patient with a complex periodontal defect that required different types of knowledge and abilities to achieve the best results based on the current status of dentistry possibilities.

Temperature Profiles Along the Root with Gutta-percha Warmed through Different Heat Sources

OBJECTIVES

To evaluate temperature profiles developing in the root during warm compaction of gutta-percha with the heat sources System B and System MB Obtura (Analityc Technology, Redmond, WA, USA). Thirty extracted human incisor teeth were used. Root canals were cleaned and shaped by means of Protaper rotary files (Dentsply-Maillefer, Belgium), and imaging was performed by micro-CT (Skyscan 1072, Aartselaar, Belgium).

METHODS

Teeth were instrumented with K-type thermocouples, and the roots were filled with thermoplastic gutta-percha. Vertical compaction was achieved through the heat sources System B and System MB, and temperature profiles were detect-ed by means of NI Dac Interface controlled by the LabView System. With both heat sources, higher temperature levels were recorded in the region of the root far from the apex. When the warm plugger tip was positioned at a distance of 3 mm from the root apex, temperature levels of about 180°C were used to soften gutta-percha, and no statistically significant differences were observed between peak temperatures developed by the two heating sources at the root apex. However, a temperature level higher than 40°C was maintained for a longer time with System MB.

RESULTS

Statistically significant differences were observed in peak temperature levels recorded far from the root apex. Thus, with a temperature of about 180°C and the warm plugger positioned at 3 mm from the root apex, both heating sources led to a temperature slightly higher than 40°C at the apex of the root, suggesting that the gutta-percha was properly softened.

SIGNIFICANCE

A temperature level higher than 40°C was maintained for a longer time with System MB, thus providing an ad-equate time for warm compaction of the gutta-percha.

A comparative study on root canal repair materials: a cytocompatibility assessment in L929 and MG63 cells

Cytocompatibility of repair materials plays a significant role in the success of root canal repair. We conducted a comparative study on the cytocompatibility among iRoot BP Plus, iRoot FS, ProRoot MTA, and Super-EBA in L929 cells and MG63 cells. The results revealed that iRoot FS was able to completely solidify within 1 hour. iRoot BP Plus required 7-day incubation, which was much longer than expected (2 hours), to completely set. ProRoot MTA and Super-EBA exhibited a similar setting duration of 12 hours. All the materials except Super-EBA possessed negligible in vitro cytotoxicity. iRoot FS had the best cell adhesion capacity in both L929 and MG63 cells. With rapid setting, negligible cytotoxicity, and enhanced cell adhesion capacity, iRoot FS demonstrated great potential in clinical applications. Future work should focus on longer-term in vitro cytocompatibility and an in vivo assessment.

Biocompatibility of root-end filling materials: recent update

The purpose of a root-end filling is to establish a seal between the root canal space and the periradicular tissues. As root-end filling materials come into contact with periradicular tissues, knowledge of the tissue response is crucial. Almost every available dental restorative material has been suggested as the root-end material of choice at a certain point in the past. This literature review on root-end filling materials will evaluate and comparatively analyse the biocompatibility and tissue response to these products, with primary focus on newly introduced materials.

Comparative evaluation of microleakage of various retrograde filling materials: An in vitro study

OBJECTIVE

The present study is envisaged to evaluate and compare the microleakage of mineral trioxide aggregate (MTA) with commonly used retrograde filling materials, like light-cured composite with dentin-bonding agents, light-cured glass ionomer cement (LC GIC) and resin-modified zinc oxide eugenol.

MATERIALS AND METHODS

Ninety freshly extracted non-carious single-rooted human anterior teeth were used in the study. They were randomly divided into four experimental groups and two control groups of 15 each. Following the biomechanical preparation, all teeth were obturated and then the apices of the obturated teeth were resected by removing 3 mm of each apex at 90° to the long axis of the tooth with a straight fissure bur in a high-speed air-rotor handpiece with water coolant. A 3-mm-deep root end cavity was prepared and the root end fillings were placed as per the manufacturer's instructions and according to the groups divided. The samples were then immersed in 1% methylene blue at room temperature for 72 h, 96 h and 1 week and the dye penetration was measured.

RESULTS AND CONCLUSION

All the four materials used in the study showed some microleakage throughout the experimental period. The sealing ability in terms of microleakage can be summarized as: MTA > Composite resin with dentin bonding agent > LC GIC > Resin modified zinc oxide eugenol.

Effect of Nd: YAG laser on the apical seal after root-end resection and MTA retrofill: a bacterial leakage study

Laser irradiation has been investigated in terms of preventing leakage in retrofilled root canals. The aim of the present study was to evaluate the effect of neodymium-doped yttrium aluminum garnet (Nd: YAG) laser on the bacterial leakage of mineral trioxide aggregate (MTA)-retrofilled roots. In this ex vivo experimental study, 90 single-rooted incisor teeth were filled with gutta-percha and AH26 sealer. The apical 3 mm of all the roots were resected and 3-mm retrocavities were prepared by an ultrasonic device. The specimens were randomly divided into two experimental (n = 25), one positive control (n = 10), and two negative control (n = 10) groups. In the laser + MTA group, the cavity walls were irradiated by Nd: YAG laser prior to MTA placement. In the MTA group, MTA was placed without laser irradiation. The root surfaces were covered with two layers of nail varnish except for the apical 2 mm. The specimens were then embedded in a bacterial leakage test system and examined daily for 90 days. Contamination periods were recorded. Data were analyzed by Kaplan-Meier and Mann-Whitney U tests (α = 0.05). Five teeth with and five teeth without laser irradiation underwent scanning electron microscopic evaluation. The specimens in the laser + MTA group were contaminated earlier than those in the MTA group (p < 0.05). Comparison of survival times between the two groups showed significant differences (p < 0.05). Nd: YAG laser irradiation can decrease the sealing capacity of MTA in comparison to the apical seal achieved by MTA without laser irradiation. Further studies are recommended to provide a better seal for the MTA-retrofilled teeth after laser irradiation.

Adhesion and biologic behavior of human periodontal fibroblast cells to resin ionomer Geristore: a comparative analysis

AIM

The resin ionomer Geristore, originally designed for restorative procedures, has been used extensively in treating subgingival defects (such as root resorption and perforations) and as a retrofilling material. The purpose of this study was to evaluate the cell adhesion as well as in vitro biocompatibility of human periodontal fibroblast cells with resin ionomer Geristore in comparison with mineral trioxide aggregate (MTA) and glass ionomer cement (GIC).

MATERIAL AND METHOD

Adhesion, growth, and morphology of human periodontal fibroblasts over test materials were evaluated by scanning electron microscopy (SEM). Biocompatibility was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide salt (MTT) assay.

RESULTS

Compared to glass coverslips, cells grew and spread qualitatively better over the surface of Geristore in comparison with the other test materials. In vitro interpretation indicates that Geristore is significantly less cytotoxic to human periodontal ligament cells. Results of statistical analysis revealed that material extracts had significant effect on cell proliferation at both 24 h (F = 547.62, P < 0.05) and at 48 h (F = 6048.18, P < 0.05).

CONCLUSION

Our study supports that Geristore has enhanced biologic behavior to human periodontal ligament cells and superior biocompatibility in comparison with MTA and GIC, so it can be suggested as a material of choice in root resorption, perforations, and root-end filling.

Comparison of the microhardness and morphology of five different retrograde filling materials in aqueous and dry conditions

The purpose of the present study was to compare the effect of dry and aqueous conditions on the surface morphology and surface hardness of five materials 24 h after being used as fillings without initial setting time in dry condition. The five materials were ProRoot mineral trioxide aggregate (MTA), super EBA, intermediate restorative materials (IRM), zinc oxide eugenol (ZOE), and amalgam. To evaluate microhardness, the five materials were submitted to the Vickers microhardness (VHN) test. We used a scanning electron microscope (Steroscan 440, Leica Cambridge, England) to observe the microstructural morphology of the five different materials. The VHN of MTA soaked in water showed five times lower than that of MTA soaked in dry condition. On the other hand, super EBA was less influenced by the medium of storage compared with the other materials. Scanning electron microscope (SEM) images showed the similar results with microhardness tests. The surface of MTA soaked in water appeared to be unstable compared with that of dry condition while super EBA showed similarly smooth surface in both conditions (aqueous and dry). In conclusion, the physical property of MTA is reduced after storage in water; however, super EBA is less influenced by aqueous condition.

Synthesis of partial stabilized cement-gypsum as new dental retrograde filling material

The study describes the sol-gel synthesis of a new dental retrograde filling material partial stabilized cement (PSC)-gypsum by adding different weight percentage of gypsum (25% PSC+75% gypsum, 50% PSC+50% gypsum and 75% PSC+25% gypsum) to the PSC. The crystalline phase and hydration products of PSC-gypsum were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The handling properties such as setting time, viscosity, tensile strength, porosity and pH, were also studied. The XRD and microstructure analysis demonstrated the formation of hydroxyapatite and removal of calcium dihydrate during its immersion in simulated body fluid (SBF) on day 10 for 75% PSC+25% gypsum. The developed PSC-gypsum not only improved the setting time but also greatly reduced the viscosity, which is very essential for endodontic surgery. The cytotoxic and cell proliferation studies indicated that the synthesized material is highly biocompatible. The increased alkaline pH of the PSC-gypsum also had a remarkable antibacterial activity.

The effects of humidity and serum on the surface microhardness and morphology of five retrograde filling materials

The purpose of this study was to compare the surface morphology and surface hardness of five materials 24 h after filling, in conditions of 100% humidity, and fetal bovine serum. The five materials were ProRoot Mineral Trioxide Aggregate (MTA), Super-EBA, Intermediate Restorative Materials (IRM), Zinc Oxide Eugenol (ZOE), and Amalgam. The microhardness of these materials was evaluated by Vickers microhardness test, and their morphologies were compared by using scanning electron microscopy (SEM). To evaluate the microhardness, the mixed five materials were measured with Vickers microhardness test. Differences between the experimental groups were analyzed by two-way ANOVA and Duncan's multiple comparison tests. All analyses were performed using the Statistical Package for the Social Sciences (SPSS Inc., Chicago, IL). For the microstructural morphological evaluation, the cross cut and root-end cavity prepared surfaces followed by retrograde filling with five different materials were observed under a Scanning Electron Microscope (Steroscan 440; Leica, Cambridge, England) at ×500. To summarize, Super EBA was less influenced by storage medium than the other materials, especially MTA. However, further long-term studies considering other factors, such as biocompatibility (i.e. cellular toxicity) and retention, are needed to be collaborated with these findings in the clinical context.

A comparative study of the effects of three root-end filling materials on proliferation and adherence of human periodontal ligament fibroblasts

INTRODUCTION

The present in vitro study was conducted with the aim of evaluating and comparing the cytotoxic effects of three root-end filling materials, ProRoot mineral trioxide aggregate (ProRoot MTA; Dentsply Tulsa Dental, Memphis, TN), MTA Angelus (Angelus, Londrina, Brazil), and a modified zinc oxide-eugenol cement (Super-EBA; Bosworth Co, Skokie, IL) on human periodontal ligament (PDL) fibroblasts.

METHODS

PDL cells were cultured in an mineral trioxide aggregate (MTA)- or a Super-EBA-conditioned medium to assess the viability as determined by the trypan blue exclusion assay. The proliferation of the cells was recorded, and the cellular morphology was observed by confocal microscopy. Moreover, PDL cell aggregates were cultured on the substrate surfaces to assess cell adhesion.

RESULTS

ProRoot MTA was found to be the most biocompatible material, whereas Super-EBA was found to be the most cytotoxic material because it significantly inhibited the cell growth and adherence on its. In the presence of ProRoot MTA, the PDL cell proliferation was almost unaltered. MTA Angelus was found to be more cytotoxic than ProRoot MTA, offering, however, excellent scaffold properties for the adhesion of cell aggregates.

CONCLUSIONS

Under the conditions of the present study, it seems that commercially available forms of MTA may behave in different ways regarding their proliferative effect on human PDL fibroblasts. ProRoot MTA appears to be the most biocompatible of the three tested materials when considering use for root-end endodontic microsurgery.

Comparison of the success rate of endodontic treatment and implant treatment

Dentists and patients are facing a perplexity between saving a compromised tooth through endodontic treatment and restoration or by extraction and replacement with an implant. The purpose of this paper was to compare the success rates of these two treatments. Success was measured as the longevity of the tooth or implant. Studies which met strict inclusion criteria to ensure best evidence were included. Searches were performed in Ovid Medline, Pubmed, Scopus database, and the Cochrane Library. Evidence-based groups were formed following the assessment of inclusion/exclusion criteria. The overall success rates for primary endodontic, nonsurgical retreatment, and surgical treatment were (86.02%), (78.2%), and (63.4%), respectively, implants was 90.9%. In conclusion, choice between implant and endodontic therapy cannot be exclusively based on outcome as both treatments differ in the biological process, diagnostic modalities, failure patterns, and patients preferences. More research is required with improved study designs before long-term success rates can be compared.

Morphological behavior and attachment of p19 neural cells to root-end filling materials

Some techniques and instruments like stereomicroscopy and confocal microscopy used for observing neural cells are too complicated and dependent on preparation and cell fixation methods. This may question the results of these methods. Though, we have used scanning electron microscopy on replicated specimens to observe p19 neural cells and their cellular extensions. This manuscript has shown the feasibility of using replica (indirect) method instead of direct methods for observing morphological characteristics of this high sensitive cell line. As neural cells are very sensitive to fixation solutions and processes, we have used replica mode and observed neural cells with a novel indirect method. We have used replica mode in this study to indirectly and noninvasively evaluate the state of p19 neural cells and their cellular extensions.

Periapical bone regeneration after endodontic microsurgery with three different root-end filling materials: amalgam, SuperEBA, and mineral trioxide aggregate

INTRODUCTION

The purpose of this study was to determine the bone regeneration potential to different root-end filling materials by evaluating the distance between the materials and newly regenerated bone after root-end surgery.

MATERIAL AND METHODS

Periapical lesions were induced in premolars and molars of five female beagle dogs. The teeth were treated endodontically after the development of the lesions. After 1 week, the teeth underwent root-end surgery using modern microsurgical techniques. Three different root-end filing materials were used: amalgam (Tytin; Kerr Mfg Co, Romulus, MI), SuperEBA (Bosworth, Skokie, IL), and mineral trioxide aggregates (MTA; Dentsply, York, PA). After 4 months, the dogs were sacrificed, and the jaws were prepared for histological sectioning. The distances from the root-end filling materials to the regenerated bone were determined by the evaluation of microradiographic images of the sections with imaging software (Sigma Scan/Image; Jandel Scientific Software, San Rafael, CA). The results were statistically analyzed with analysis of variance using Sigma Stat software (Jandel Scientific Software, San Rafael, CA).

RESULTS

The mean distances from the newly regenerated bone were 0.397 +/- 0.278 mm in the MTA group, 0.756 +/- 0.581 mm in the SuperEBA group, and 1.290 +/- 0.386 mm in the amalgam group. There was a statistically significant difference between the amalgam and MTA groups (p < 0.05). No significant differences existed for amalgam versus SuperEBA and SuperEBA versus MTA.

CONCLUSION

MTA showed the most favorable periapical tissue response. The distance from MTA to the regenerated bone was similar to the normal average periodontal ligament thickness in dogs.

In vitro comparison of three materials as apical sealants of equine premolar and molar teeth

REASONS FOR PERFORMING STUDY

Surgical endodontic therapy is a conservative dental technique used in horses with some degree of clinical success. Failure of this procedure can partially be explained by inadequate sealing of the root apices with resultant microleakage in the periapical area.

OBJECTIVES

To assess and compare in vitro sealing ability of 3 different dental restorative materials used as apical sealants during equine surgical endodontics.

METHODS

Thirty extracted equine cheek teeth were divided randomly into 3 groups and subjected to apicoectomy and apical sealing using 3 materials: reinforced zinc oxide-eugenol cement; intermediate restorative material (IRM); a resin-modified glass ionomer; and amalgam. After apical sealing, the teeth were submerged in a solution of Procion Brilliant Cresyl Blue stain for a period of 7 days. The teeth were then washed, embedded in resin, sectioned and assessed microscopically for dye leakage around the apical restorations.

RESULTS

Although the materials proved effective as apical sealants, some dye leakage was encountered in all 3 groups with no statistical difference (P = 0.114).

CONCLUSIONS AND POTENTIAL RELEVANCE

IRM, a resin-modified glass ionomer and amalgam all showed comparative features as apical sealants when used in vitro in equine teeth. IRM is currently regarded as the superior material in clinical situations due to its ease of handling and lesser sensitivity to environmental moisture during placement compared to the other 2 materials.

Effect of intraosseous anesthesia on control of hemostasis in pigs

INTRODUCTION

Intraosseous anesthesia is used to deliver anesthetic into cancellous bone adjacent to the root apices. No study has assessed the effect of this anesthetic technique on hemostasis. The purpose of this study was to compare the amount of bleeding from soft tissue and bone in pig jaws after preoperative intraosseous or infiltration anesthesia with 2% lidocaine containing 1:50,000 epinephrine.

METHODS

Twelve pigs were divided into 3 groups. The first group received infiltration anesthesia on one half of the jaw and no anesthesia on the other half. The second group received intraosseous anesthesia on one half of the jaw and no anesthesia on the other half. The third group received infiltration anesthesia on one half of the jaw and intraosseous anesthesia on the second half. Blood was collected during flap reflection to measure the volume of soft tissue bleeding. Osteotomies were then prepared with blood collected from the surgical site to measure the volume of osseous bleeding.

RESULTS

The median soft tissue blood loss observed in animals receiving infiltration anesthesia (1.14 mL) was significantly less as compared with animals that received no anesthesia (4.49 mL) or intraosseous anesthesia (2.45 mL). Compared with median hard tissue blood loss observed in animals without anesthesia (1.51 mL), significantly less blood loss was observed in animals receiving either infiltration anesthesia (0.67 mL) or intraosseous anesthesia (0.76 mL).

CONCLUSIONS

Infiltration anesthesia resulted in significantly less soft tissue bleeding (p = .004) as compared with no anesthesia. Infiltration and intraosseous anesthesia resulted in significantly less osseous bleeding than the use of no anesthetic (p < .001). The volume of blood loss for each animal was shown to be below the maximum safe volume of blood loss for a single procedure.

Endodontic surgery with and without inserts of bioactive glass PerioGlas--a clinical and radiographic follow-up

OBJECTIVE

This study evaluated the use of bioactive glass, PerioGlas, after retrograde filling with Super EBA cement in the treatment of periapical bone destruction.

STUDY DESIGN

Healing outcomes were followed up after endodontic surgery in 186 teeth. Outcomes were divided into two groups according to follow-up time: short- and long-term. The EBA group (n = 110) underwent endodontic surgery and retrograde filling with EBA cement. In the EBA + PerioGlas group (n = 76), PerioGlas was embedded in the bone cavity after retrograde filling.

RESULTS

The success rate in the EBA + PerioGlas group was 72% compared with 56% in the Super EBA group at the short-term follow-up and 74% and 84%, respectively, at the long-term follow-up. Healing of periapical bone destruction classified as uncertain at the short-term follow-up was considered successful in two out of three cases at the long-term follow-up.

CONCLUSION

This study found that PerioGlas as bone substitute did not significantly improve endodontic healing outcome.

Sealing ability of white and gray mineral trioxide aggregate mixed with distilled water and 0.12% chlorhexidine gluconate when used as root-end filling materials

This in vitro study used dye penetration to compare the sealing ability of white and gray mineral trioxide aggregate mixed with distilled water and 0.12% chlorhexidine gluconate when used as root-end filling materials. Ninety-six single-rooted human teeth were cleaned, shaped, and obturated with gutta-percha and AH26 root canal sealer. The apical 3 mm of each root was resected, and 3-mm deep root-end cavity preparations were made. The teeth were randomly divided into 4 experimental groups, each containing 20 teeth, and 2 negative and positive control groups, each containing 8 teeth. Root-end cavities in the experimental groups were filled with the experimental materials. After decoronation of the teeth and application of nail polish, the teeth were exposed to India ink for 72 hours and longitudinally sectioned, and the extent of dye penetration was measured with a stereomicroscope. Statistical analysis showed that there were no significant differences among the 4 experimental groups.

Reactions of connective tissue to amalgam, intermediate restorative material, mineral trioxide aggregate, and mineral trioxide aggregate mixed with chlorhexidine

The aim of this study was to histopathologically examine the biocompatibility of the high-copper amalgam, intermediate restorative material (IRM), mineral trioxide aggregate (MTA), and MTA mixed with chlorhexidine (CHX). This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted tubes filled with amalgam, IRM, MTA, and MTA mixed with CHX. The animals were sacrificed 15, 30, and 60 days after the implantation procedure. The implant sites were excised and prepared for histological evaluation. Sections of 5 to 6 microm thickness were cut by a microtome and stained with hemotoxylin eosin and examined under a light microscope. The inflammatory reactions were categorized as weak (none or few inflammatory cells < or =25 cells), moderate (>25 cells), and severe (a lot of inflammatory cells not to be counted, giant cells, and granulation tissue). Thickness of fibrous capsules measured five different areas by the digital imaging and the mean values were scored. Amalgam, IRM, and MTA mixed with CHX caused a weak inflammatory response on days 15, 30, and 60. MTA provoked an initial severe inflammatory response that subsided at the 30 and 60 day study period. A clear fibrous capsule was observed beginning from the 15 days in all of the groups. Within the limits of this study, amalgam, IRM, MTA, and MTA mixed with CHX materials were surrounded by fibrous connective tissue indicated that they were well tolerated by the tissues, therefore, MTA/CHX seemed to be biocompatible.

Determining the apical terminus of root-end resected teeth using three modern apex locators: a comparative ex vivo study

AIM

To assess ex vivo the accuracy of various electronic apex locators in locating the apical terminus of root-end resected teeth.

METHODOLOGY

Ninety extracted human posterior teeth (182 root canals) were prepared to a minimum size of 40 and filled with gutta-percha and sealer. After resection of the apical 3 mm of the root, the root canal filling was removed using HERO rotary instruments. The size of the root canal at the apical terminus after removal of the filling ranged from size 50 to 90. The root canal length to the apical terminus was determined using 3 apex locators (Root ZX, Raypex4 and Apex Pointer). A new mounting model that utilized a micrometer was used to perform the measurements and to visually determine the actual position of the apical terminus. The frequency of locating the apical terminus and the corresponding 95% confidence interval (CI) were calculated. Additionally, the coefficient of repeatability of each apex locator and the limits of inter-operator agreement were determined.

RESULTS

All apex locators showed an acceptable repeatability (0.02-0.03 mm coefficient of repeatability) and narrow limits of inter-operator agreement (+0.07 and -0.07 mm). The accuracy of determining the apical terminus within 1 mm in the root canal was as follows: Root ZX 90% (164/182 root-canals) [95%CI: 86-94%], Raypex4 74% (135/182 root-canals) [95%CI: 68-80%], and Apex Pointer 71% (129/182 root canals) [95%CI: 65-77%]. No over-instrumentation resulted when the Root ZX device was used. In contrast, using the Raypex4 or the Apex Pointer device resulted in over-instrumentation in 8 of 182 root canals (4%).

CONCLUSIONS

Under the conditions of this study all three apex locators were able to detect the apical terminus of root-end resected teeth with an acceptable range. The Root ZX device was the most accurate without over-instrumentation of the root canals.

Apicectomy with the Er:YAG laser or bur, followed by retrograde root filling with zinc oxide/eugenol or sealer 26

OBJECTIVE

This study evaluated the influence of root resection, by means of the use of erbium:YAG laser in sealing two different materials, OZE and Sealer 26, in retrograde obturations.

BACKGROUND DATA

Few studies with sufficient data have been conducted in this area.

METHODS

Forty uniradicular teeth were used. They were biomechanically prepared using the step-back technique and obturated using the lateral condensation technique. The teeth were divided into two groups of 20 teeth, one group using the erbium:YAG laser (350 mJ and 6 Hz) for the resection process and the other using the Zekrya Drill, in high rotation. Then, the retrograde cavities were prepared using a micro counter-angle with a number 2 spherical bur. After preparing the cavities, the teeth were impermeabilized and divided into two subgroups. One subgroup used the retrograde obturation technique with Sealer 26 cement, and the other subgroup used OZE. After completing the retrograde obturation, the teeth were immersed in 2% methylene blue for a 7-day period. Teeth were then removed from the dye, washed, scraped, and sectioned in the vestibule-lingual direction.

RESULTS

The results were analyzed with the aid of a magnifying lens, and scores were attributed based on the magnitude of infiltration. The data were then submitted to statistical analysis.

CONCLUSIONS

No statistical difference was noticed regarding the root resection methods; however, in comparing materials, Sealer 26 was statistically superior to OZE. In the subgroup comparison, a significant difference was noticed in the Laser and Sealer 26 and the Laser and OZE and bur and OZE.

Behaviour of bone marrow osteoblast-like cells on mineral trioxide aggregate: morphology and expression of type I collagen and bone-related protein mRNAs

AIM

To investigate the in vitro behaviour of rat bone marrow cells (RBM) on mineral trioxide aggregate (MTA) (ProRoot, MTA Root Canal Repair Material; Dentsply Tulsa, Tulsa, OK, USA) compared with intermediate restorative materials (IRM) (Dentsply Caulk, Milford, DE, USA).

METHODOLOGY

RBM were obtained from rat femur and were primary cultured and then subcultured. Cells were then seeded on three dishes of each material, and cultured for 3 days, after which they were evaluated morphologically using scanning (SEM) and transmission (TEM) electron microscopy. Furthermore, the calcium released from hydrated material, the cell proliferation ratio and alkaline phosphatase (ALP) activity were analysed, and the expression of type I collagen and bone-related protein mRNAs were evaluated. The data were averaged and analysed via one-way analysis of variance (anova) and were then compared by the Scheffe's test.

RESULTS

SEM showed that RBM attached to MTA and had a flattened appearance without nuclear protrusions and microspikes. TEM showed that the cells attached in the same manner as the control group, but gaps larger than 2 microm were frequently seen. The calcium released from hydrated MTA was about 130 ppm after 3 days of immersion in saline. The ALP activity was similar to the control group. Cell proliferation and expression of type I collagen mRNA was significantly lower, while the expression of osteopontin mRNA was significantly higher than the control group at the third day of culture. In IRM groups, a few rounded cells were observed on the material but no living cells were seen.

CONCLUSIONS

MTA is a material of low toxicity which does not inhibit cell growth, but does suppress the differentiation of osteoblast-like cells.

Effects of root-end filling materials and eugenol on mitochondrial dehydrogenase activity and cytotoxicity to human periodontal ligament fibroblasts

Various root-end filling materials have been used to prevent the entry of root-canal pathogens into periapical regions. Five root-end filling materials were compared regarding the cytotoxicity, apoptosis, and mitochondrial dehydrogenase (MDH) activities of human periodontal ligament (PDL) fibroblasts, with the use of a novel transwell culture system. Exposure to IRM (a ZnO eugenol-based intermediate restorative material), a 2-ethoxybenzoic acid cement (Super EBA), and amalgam for 3 days inhibited the MDH activity of PDL fibroblasts as indicated by decrease in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) reduction by 97%, 95%, and 51%, respectively. Evident suppression of MTT reduction by amalgam and glass ionomer cement (GIC) was noted after 5 days of exposure, with 73% and 46% of inhibition, respectively. Mineral trioxide aggregates (MTA) showed little effect on MDH activity. IRM and Super EBA were cytotoxic to PDL fibroblasts as indicated by a trypan blue dye exclusion technique. GIC and amalgam showed mild cytotoxicity. IRM, GIC, and amalgam further induced apoptosis of PDL cells, as revealed by the presence of sub-G0/G1 DNA content in flow cytometric histogram. Twenty-four-hour exposure to IRM and Super EBA elevated the MDH activities to 156% and 117%, correspondingly, of that of control. Eugenol, a phenolic ingredient in Super EBA and IRM, also increases MDH activity of PDL fibroblasts by 45% and 51%, at concentrations of 0.5 and 1 mM. However, at concentrations higher than 0.5 mM, eugenol decreased the number of viable PDL fibroblasts. These results suggest that MTA is a biocompatible root-end filling material, followed by self-curing Fuji II GIC and amalgam. IRM and Super EBA ingredients induced marked cytotoxicity and transiently stimulate MDH activities, which is possibly due to their content of eugenol and induction of cellular adaptive response.

A new quantitative method using glucose for analysis of endodontic leakage

OBJECTIVE

The purpose of this study was to introduce a new method for quantitative testing of endodontic leakage.

STUDY DESIGN

Eighty straight maxillary anterior teeth were divided randomly into 3 experimental groups of 20 samples each and 2 control groups. The experimental groups were prepared using the modified double-flared technique and obturated by lateral compaction of cold gutta-percha with Pulp Canal Sealer EWT, Sealapex, or AH Plus sealer. With the leakage test device, coronal 1 mol/L glucose solution was forced under a hydrostatic pressure of 1.5 kPa toward the apical part of the root. Leakage was measured by the concentration of leaked glucose in apical reservoir at 1, 2, 4, 7, 10, 15, 20, and 30 days with the enzymatic glucose oxidase method.

RESULTS

No significant difference of sealing ability was found among 3 test groups at 1, 2, 4, and 7 days. From the tenth day, Pulp Canal Sealer EWT showed the highest leakage, and the leakage was not significantly different between Sealapex and AH Plus.

CONCLUSIONS

The quantitative method is sensitive, nondestructive, and clinically relevant. Pulp Canal Sealer EWT showed more leakage than Sealapex and AH Plus in most observation time.

Scanning Electron Microscopy (SEM) and Optical Microscopy: Effects of Er:YAG and Nd:YAG Lasers on Apical Seals after Apicoectomy and Retrofill

OBJECTIVE

This study evaluated the dentinal and marginal permeability of the cut surface after apicoectomy, treatment and retrocavity preparation with Er:YAG and Nd:YAG lasers. Furthermore, scanning electron microscopy (SEM) analysed the morphological alteration of dentin caused by laser irradiation through an optical fiber.

BACKGROUND DATA

Numerous studies have shown the beneficial effects of laser treatment upon sealing dental apex, avoiding the changes of organic fluids, microorganisms and their by-products between the root canal system and periapex.

MATERIALS AND METHODS

Twenty-four extracted and endodontically treated teeth were divided into three groups: GI, apices were resected with Er:YAG laser (350 mJ; 4 Hz) treatment of cut dentinal surface and retrocavity were lased with this same laser (120 mJ; 4 Hz; bur 2051) using the optical fiber 50/10; GII, apicoectomy was performed similar to GI, however the cut dentinal surface was treated with Nd:YAG laser through optical fiber, as well as the retrocavity preparation (100 mJ; 15 Hz; 1.5 W); and GIII (control group), high speed burs were used.

RESULTS

Analysis of methylene blue dye penetration into dentin demonstrated that the specimens of the groups irradiated with laser showed to have lower infiltration indices than the control group. These results were compatible with structural and morphological injuries, evidenced by SEM.

CONCLUSION

Under the conditions of the present study, apicoectomy using Er:YAG laser, followed by dentinal surface irradiation and retrocavity preparation with Nd:YAG laser, showed to be an alternative clinical tool able to reduce the dentinal permeability.

Survival of surgical endodontic treatment performed in a dental teaching hospital: a cohort study

AIM

To assess the survival function of surgical endodontic treatment performed at least 1 year before in a dental teaching hospital.

METHODOLOGY

A total of 194 teeth surgically treated between 1991 and 2001 were recalled and examined clinically and radiographically using a set of strict criteria. The Kaplan-Meier method and log rank test were used to evaluate the survival time. Confounding factors were examined by Cox regression analysis.

RESULTS

The median survival time of the 154 first-time surgically treated teeth was 92.1 months (95% CI: 40.9-143.4) and that of the 40 resurgery cases was 39.1 months (95% CI: 6.1-72.1) up to the date of recall. There was a significant difference in the length of survival between the two groups. For those first-time surgery cases, the preoperative marginal bone loss and the operator had a significant influence on the survival time (P < 0.05).

CONCLUSIONS

The survival of surgical endodontic treatment declined nonlinearly with time. The preoperative marginal bone loss, operator and resurgery were important factors affecting the survival of this treatment modality.

Infected immature teeth treated with surgical endodontic treatment and root-reinforcing technique with glass ionomer cement

The authors propose surgical endodontic treatment of immature teeth characterized by necrosis and infection, especially after failure of apexification or in the presence of older, fibrous, and extensive lesion. A glass ionomer cement, autopolymerizable and condensable, is used as retro-filling material and as a reinforcement material for the canal walls. The variety of different cases presented here show that this rapid technique is reliable and reproducible.

The influence of root-end resection and root-end cavity preparation on microleakage of root filled teethin vitro

AIM

To investigate in vitro the influence of root-end resection and root-end cavity preparation on leakage of root filled teeth.

METHODOLOGY

The root canals of 48 roots, 16 mandibular premolars (G1), 16 mandibular incisors (G2) and 16 maxillary incisors (G3), 12 mm in length, were enlarged using a modified 'balanced force' technique and filled with gutta-percha and sealer using lateral compaction. After setting, leakage along the canal was measured using a fluid transport model. Root-end resection and root-end cavity preparation were then performed, leaving roots 10 mm in length with root fillings of 7 mm (groups R1, R2 and R3, respectively). Fluid transport was measured again along the remaining root fillings of all groups using the same experimental conditions. Results of leakage before and after root-end resection were analysed statistically using the Kruskal-Wallis and Wilcoxon tests.

RESULTS

A total of 31% of the roots leaked before and 54% after root-end preparation; the difference was significantly different (P < 0.001). No significant differences were found either among groups G1, G2, G3 (P = 0.565) or among groups R1, R2, R3 (P =0.2628). Significant differences, however, were shown between groups G1-R1 (P = 0.0053), G2-R2 (P =0.0089) and G3-R3 (P = 0.0461).

CONCLUSIONS

Root-end resection and root-end cavity preparation compromised the seal of 7 mm root fillings in all tooth groups. Increased leakage was recorded in the following order: mandibular incisors > mandibular premolars > maxillary incisors.

Attachment and morphological behavior of human periodontal ligament fibroblasts to mineral trioxide aggregate: a scanning electron microscope study

The attachment and morphology of human periodontal ligament fibroblasts to mineral trioxide aggregate (MTA) was evaluated using a scanning electron microscope. The material was placed at an apical cavity of 30 single-rooted slices of extracted human teeth. The specimens were divided into two groups of 15 root slices each (freshly mixed and set state). For each experimental group, five root slices were used per observation period (4, 8, and 24 h). A set of two glass slides was used per observation period for the control group. The experiments were performed in tissue-culture cluster 96-well plates in which 1 ml of human periodontal ligament fibroblast cell suspension was placed over the MTA filling and the control glass slides. For the positive-control group, 0.5 ml of methyl methacrylate 2% (vol/vol) was added to the cell suspensions before being dispensed into the wells. Results showed the normal cell morphology in the negative controls. Few round cells with less smooth surfaces and many rough blebs were seen in the positive control, and most of these cells did not show any attachment to the substratum. Similar observations were seen with the freshly prepared-MTA group. In the set-MTA group, cells were round and flattened, displayed smooth surfaces, and appeared to be tightly attached to MTA. It was concluded that the quality and quantity of cell attachment to the retrofilling material could be used as a criterion to evaluate material's toxicity. This research (FN#1077) is registered with the College of Dentistry research center, King Saud University, Riyadh, Saudi Arabia. The author thanks the administration of the King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia, and in particular Dr. M. N. Al-Ahdal for providing the use of the Molecular Virology and Infectious Disease Laboratory, Mr. Yunus Siddiqui for his support, and Dr. Saad AL-Nazhan for his assistance in preparing the manuscript.

Reactions of connective tissue to mineral trioxide aggregate and amalgam

The purpose of this study was to evaluate the subcutaneous connective tissue reactions to ProRoot, mineral trioxide aggregate (MTA; Dentsply), and Oralloy, high-copper amalgam (Coltene). These materials were placed in polyethylene tubes and implanted into dorsal connective tissue of Wistar albino rats, and tissue biopsies were collected and histologically examined 7, 15, 30, 60, and 90 days after the implantation procedure. The presence of inflammation, predominant cell type, calcification, and thickness of fibrous connective tissue were recorded. Scores were defined as follows: 0, none or few inflammatory cells, no reaction; 1, < 25 cells, mild reaction; 2, 25 to 125 cells, moderate reaction; 3, > or = 125 cells, severe reaction. Fibrous capsule was categorized as "thin" when thickness was < 150 microm and "thick" at > 150 microm. Necrosis and formation of calcification were recorded. Both materials were well tolerated by the tissues in a 90-day evaluation period. One notable finding is the presence of dystrophic calcification in connective tissue adjacent to MTA; this finding is consistent with the hypothesis of hard tissue induction by this material.

The use of glass ionomer cements in both conventional and surgical endodontics

The capacity to bond to dental tissues, especially to dentine, their long-term fluoride release and their biocompatibility make glass ionomer cements (GICs) advantageous for use in endodontics, as well as in restorative dentistry. This review provides information on the basic properties of GICs, such as adhesion, antimicrobial effects and biocompatibility, particularly as they relate to use in endodontics. Indications for the use of GICs in endodontics are orthograde root canal sealing, root-end filling, repair of perforations and root resorption defects, treatment of vertical fractures and maintenance of the coronal seal. The paper includes a review on each of these indications. It is concluded that in spite of the critical handling characteristics and the inconclusive findings regarding sealing ability and antimicrobial activity, there is substantial evidence to confirm their satisfactory clinical performance. Both soft tissue and bone compatibility make them suitable for use during endodontic surgery.

Biocompatibility of human osteosarcoma cells to root end filling materials

Ideal root end filling materials should have good physical and chemical properties, and the most important is that the material should be biocompatible with periradicular tissue. The biocompatibility of three root end filling materials, mineral trioxide aggregate, calcium hydroxide-based cement, and eugenol-based cement, were investigated in vitro by culturing extracts of these materials with human osteogenic sarcoma cells (U2OS). Extracts of each of the materials were made after incubation of the materials for 1 day and 1 week with complete McCoy's medium. The extracts were serially diluted and then incubated with U2OS cells for 24 and 48 h. Cell survival rates were assessed by means of a viability assay for mitochondrial dehydrogenase activity. Differences in mean cell survival rates were statistically assessed using one-way ANOVA. Results showed that the survival rates of U2OS cells were largest with mineral trioxide aggregate, followed by calcium hydroxide-based cement and eugenol-based cement at 24- and 48-h exposures using the 1-day and 1-week extracts. The duration of root end filling material extraction time and treatment time showed variable influence on the survival rates. The results suggest that mineral trioxide aggregate is more biocompatible than the other root end filling materials and is suitable for use in the clinical setting.