Evaluation of antibacterial activity of propolis on regenerative potential of necrotic immature permanent teeth in dogs.

BACKGROUND: This study evaluated the antibacterial efficiency and ability of propolis to promote regeneration of immature permanent non-vital dogs' teeth. METHODS: Ninety six immature permanent premolars teeth in 6 mongrel dogs were divided randomly into: experimental teeth (N = 72) and control teeth (N = 24). Periapical pathosis was induced in all experimental and positive control teeth. Experimental teeth were classified according to the used intra-canal medication into: group I (N = 36), propolis paste was used and group II (N = 36), triple antibiotic paste (TAP) was used. Bacteriologic samplings were collected before and after exposure to intra-canal medicaments. After the disinfection period (3 weeks), revascularization was induced in all experimental teeth. Each group was subdivided according to the root canal orifice plug into: subgroup A (N = 18), propolis paste was used and subgroup B (N = 18), mineral trioxide aggregates (MTA) was used. Each subgroup was further subdivided according to the evaluation period into 3 subdivisions (6 teeth each): subdivision 1; after 2 weeks, subdivision 2; after one month and subdivision 3; after 2 months. Positive control group had 12 teeth with induced untreated periapical pathosis. Negative control group had 12 untouched sound teeth. All teeth were evaluated with radiography and histology. The bacteriologic and radiographic data were analyzed using repeated measures ANOVA and post-hoc Tukey tests. The histologic data were analyzed using Kruskal-Wallis test, Mann-Whitney U test with Bonferroni's adjustment and Chi-square test. The significance level was set at P ≤ .05. RESULTS: There was no significant difference in the antibacterial effectiveness between TAP and propolis groups (P > .05). In all subdivisions, there was no significant difference between the experimental groups in terms of increase in root length and dentin thickness, decrease in apical closure, new hard tissue formation, vital tissue formation inside the pulp canal and apical closure scores (P > .05). CONCLUSION: Propolis can be comparable with TAP as a disinfection treatment option in regenerative endodontic. As a root canal orifice plug after revascularization of necrotic immature permanent teeth in dogs, propolis induces a progressive increase in root length and dentin thickness and a decrease in apical diameter similar to those of MTA.

Effect of MTA particle size on periapical healing.

AIM: To examine the effect of reduction in MTA particle size on dento-alveolar and osseous healing in dogs. METHODOLOGY: Root canals of 24 mandibular premolars in four 2-year-old beagles were prepared and filled with gutta-percha and sealer. Two to four weeks later, during periapical surgery, the root-end cavity preparations in these teeth were filled with either grey ProRoot MTA or modified (reduced particle sizes with faster setting time) MTA. The animals were sacrificed 4 months later. Degrees of inflammation, type of inflammatory cells, fibrous connective tissue adjacent to the root-end filling materials, cementum formation over the resected roots and root-end filling materials and bone healing were examined. Data were analysed using the McNemar test. RESULTS: No significant differences in healing of periapical tissues were found when comparing ProRoot MTA to a modified MTA containing reduced particle sizes. CONCLUSION: Reducing the particle sizes of MTA did not impact its biological properties.

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.

Tissue response to root canal irrigation systems in dogs' teeth with apical periodontitis.

OBJECTIVES: The aim of this study was to compare the efficacy of apical negative pressure irrigation (ANP) and passive ultrasonic irrigation (PUI) with apical positive pressure irrigation (PP-conventional irrigation) in the periapical repair of dogs' teeth with apical periodontitis. METHODS: Forty-nine mesial and distal root canals of premolars of three dogs with experimentally induced periapical lesions were subjected to a single-session root canal treatment. The teeth were randomly assigned to three groups: ANP, PUI, and PP (control). After 180 days, the animals were euthanized, and the anatomic pieces were removed and subjected to histotechnical processing for morphological and morphometric histological analyses of hematoxylin and eosin (HE)-stained sections under conventional and fluorescence microscopy. Periapical lesion size before and 180 days after root canal treatment was measured by periapical radiographic examination. Tartrate-resistant acid phosphatase (TRAP) histoenzymology was performed for osteoclast counting and Brown and Brenn staining to assess bacteria. Data were analyzed statistically by the Kruskal-Wallis test (α = 5 %). RESULT: There were no statistically significant differences among the groups regarding periapical lesion size in the radiographic evaluation (p = 0.91). In the comparison of histopathological parameters, group ANP presented more homogeneous results. There was a statistically significant difference (p = 0.02) between groups ANP and PP, with better results for group ANP in which milder infiltrate inflammatory was observed. No statistically significant difference (p > 0.05) was found among the groups with respect to periodontal ligament space, presence of mineralized tissue resorption, size of the periapical lesions, and number of osteoclasts. CONCLUSION: Although the three irrigation systems elicited similar periapical tissue response with respect to almost all evaluated parameters, ANP presented the mildest inflammatory infiltrate, suggesting an advantage over PP in the indication for clinical use. CLINICAL RELEVANCE: Irrigation of the root canal systems is an extremely important step in root canal treatment. Therefore, it is of relevance to evaluate the efficacy of these systems by in vivo experimental models to provide scientific background for the clinical practice.

Apical extrusion of sodium hypochlorite activated with two laser systems and ultrasonics: a spectrophotometric analysis.

BACKGROUND: The aim of the present study was to compare the effect of ultrasonically or laser (Nd:YAG or diode) activated irrigation on the irrigating solution extrusion compared to non-activated syringe irrigation. METHODS: Extracted mandibular premolar teeth (n = 48) with single canals were instrumented. The teeth were secured through the lid of an Eppendorf tube filled with 1.0 mL distilled water to collect the apically extruded irrigating solution. The teeth were randomly divided into four groups: non-activated syringe irrigation, diode laser, Nd:YAG laser and passive ultrasonic irrigation (PUI) using 2% NaOCl. The irrigating solution extruded through the apical foramen was collected in the Eppendorf tube and evaluated by a chemical reaction with using a spectrophotometer. The data was analyzed using one-way ANOVA and Tukey's post hoc test (α = 0.05). RESULTS: All the groups showed apically extruded irrigating solution. There were significant differences among the groups (p < 0.05). Nd:YAG laser activated irrigation showed greater extrusion (p < 0.05), while the non-activated syringe irrigation showed less extrusion (p < 0.05). Only the difference between diode laser and PUI was not statistically significant (p > 0.05). CONCLUSION: Within the limitations of this in vitro study, the researchers concluded that non-activated syringe irrigation caused less apically extruded irrigating solution than PUI and LAI using Nd:YAG or diode lasers.

[Accidental injection sodium hypochlorite during endodontic therapy. Better understand to better manage]. / Injection accidentelle d'hypochlorite de sodium au cours d'un traitement endodontique. Mieux comprendre pour mieux gérer.

The high frequency of iatrogenic incidents during endodontic treatment is a source of stress for the practitioner. These incidents may occur during the different steps of a root canal treatment. During irrigation, extrusion of sodium hypochlorite beyond the apex is a rare but impressive accident. Sodium hypochlorite, is the most common irrigant used in modern endodontics, but when it comes in contact with the periapical tissue, it can cause complications ranging from mild discomfort to serious tissue damage such as the hematoma and hemato-emphysema. The aims of this article are to discuss through the presentation of two clinical cases: Etiological and predisposing factors; Signs guiding to suspicion of accidental injection of sodium hypochlorite. In this work, we focused on clinical keys that help the practitioner in better understanding this accident in order to prevent it or to manage it well when it occurs.

A comparative study of the debridement efficacy and apical extrusion of dynamic and passive root canal irrigation systems.

BACKGROUND: Root canal irrigation carries a risk of extrusion of irrigant into the periapical tissues which can be associated with pain, swelling, and tissue damage. Studies have shown less extrusion with sonic or apical negative pressure devices compared with syringe and side-port needle or passive ultrasonic irrigation with continuous irrigant flow. This study aimed to evaluate the effectiveness of the EndoVac irrigation system, regarding 1) debris removal and 2) the control of apically extruded irrigating solution. METHODS: Fifty extracted human single-rooted teeth were used in this study. The teeth were then randomly divided into three experimental groups according to the type of irrigation used and one control group. In group 1, irrigation was performed using the EndoVac irrigation system. In group 2, irrigation was performed using a 30-gauge, tip-vented irrigation needle. In group 3, irrigation was performed using a 30-gauge, side-vented irrigation needle. The control group received instrumentation with no irrigation to serve as a control for cleaning efficiency. Root canal instrumentation was performed using the Profile NiTi rotary system with a crown-down technique. All of the experimental teeth were irrigated with the same amount of 5.25% sodium hypochlorite. The amount of extruded irrigating solution was then measured by subtracting the post-instrumentation weight from the pre-instrumentation weight using an electronic balance. The cleanliness of debris removal was evaluated using scanning electron microscopy. RESULTS: EndoVac irrigation had the least amount of extrusion followed by the side-vented and tip-vented method. The difference between the groups was statistically significant (P <0.01). As for the cleaning results, the debris collection in the EndoVac and tip-vented groups was the least in the apical third. In the control and the side-vented groups, the debris was the greatest in the apical third, but this difference was not significant among the three experimental groups. CONCLUSIONS: The EndoVac irrigation system extruded significantly less irrigant solution than either needle irrigation system. Debris collection was the least in the apical third for the EndoVac irrigation system. No significant difference was found in the cleaning efficiency among the three irrigation systems.

Oral tissue complications during endodontic irrigation: literature review.

The literature concerning the etiology, symptomatology and management of complications during root canal irrigation is reviewed. Clinical symptoms are discussed, as well as preventive and therapeutic considerations.

Periapical tissue response after use of intermediate restorative material, gutta-percha, reinforced zinc oxide cement, and mineral trioxide aggregate as retrograde root-end filling materials: a histologic study in dogs.

PURPOSE: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model. MATERIALS AND METHODS: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values. RESULTS: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials. CONCLUSIONS: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested.

Sodium hypochlorite accident with evaluation by cone beam computed tomography.

AIM: To show the radiographic manifestation of sodium hypochlorite after accidental injection past the apical foramen and into the soft tissues. SUMMARY: A female patient was seen for an emergency visit after suffering a sodium hypochlorite accident at her general dentist's office. The patient was seen within 1 h of the accident and was in pain associated with facial swelling. Radiographs, including a Cone Beam Computed Tomography (CBCT), and photographs were taken. Endodontic emergency treatment was initiated. The patient was reassured and given pain medication and antibiotics. Follow-up visits were scheduled over 6 days when the swelling had resolved. KEY LEARNING POINTS: • Importance of multiple radiographic images during preoperative endodontic evaluation when undertaking endodontic retreatment. • Knowledge of apical anatomy as related to surrounding structures. • Effect of sodium hypochlorite when injected in the soft tissues.

[General and local factors affecting periapical reparation after endodontic procedures].

Eighty-seven teeth with 100 periapical destruction foci have been treated in 78 patients from 19 to 60 years of age. In 28 patients calcium-containing preparation was administrated orally for 1 to 3 months. The dynamics of destruction foci changes was similar in all patients though among patients with satisfactory X-ray findings 64% took calcium-containing preparation. No considerable difference in the regeneration dynamics was revealed in patients with somatic diseases and healthy individuals. The residual destruction size 12 months later correlated positively with the initial size of destruction area.

A controversial role for IL-12 in immune response and bone resorption at apical periodontal sites.

Periapical lesions are inflammatory conditions of tooth periapical tissues, triggered by dental pulp infection and characterized by exudation of immune cells to the affected tissues and production of inflammatory mediators such as cytokines. The inflammatory periapical reaction is mainly driven by Th1, Th2, and Th17 responses, and such polarization may modulate progression of the disease and expression of bone proresorptive cytokines. IL-12 is a potent inducer of IFN-γ production, which stimulates Th1 effector cells. Many evidences have shown a positive correlation between the bone resorptive cytokine IL-1ß and the production of IL-12 and IFN-γ. Furthermore, IL-12 may have a potential role in the release of bone resorptive mediators and blockade of Th2 cytokines, affecting the progression of periapical bone loss. Nevertheless, IL-12 and IFN-γ have also been described as suppressors of osteoclast differentiation and activation, favoring bone maintenance. This paper focuses on the controversial roles of IL-12 in periapical lesions.

Root canal complications: 'the hypochlorite accident'.

Root canal treatment is performed routinely in dental practice, using sodium hypochlorite which serves as an effective irrigant. The literature reviewed shows that several complications following irrigation with sodium hypochlorite may occur, but few practitioners are aware of it and its management. Such complications include injury to skin, oral mucosa and eyes, damage to clothing, air emphysema, allergic reactions, and injection beyond the foramen. In this article, a case report of injection with sodium hypochlorite beyond the foramen is presented, together with a review of the recent literature regarding common manifestations and case histories. The literature shows no standard management of this condition, but symptomatic therapies are discussed. It is important to minimize the risk of sodium-hypochlorite-induced damage during root canal therapy by use of protective measures, appropriate instrumentation and techniques, and consider alternate irrigation solutions.

Histologic Response of Human Pulp and Periapical Tissues to Tricalcium Silicate-based Materials: A Series of Successfully Treated Cases.

Pulpal/periapical responses of human teeth that are treated successfully with tricalcium silicate-based materials are extremely difficult to obtain because of the typical unavailability of these teeth for histologic examination. The present case series reports histologic and histobacteriologic findings of 3 human teeth that had undergone pulpotomy, orthograde retreatment, and apicoectomy/root-end filling using tricalcium silicate-based endodontic materials. The teeth were extracted after 34 days, 7 weeks, and 20 months, respectively, because of unusual circumstances. The extracted teeth were processed, paraffin embedded, sectioned, stained with hematoxylin-eosin or the modified Brown and Brenn technique, and examined with light microscopy. The recurrent observation for the 3 cases presented was the absence of inflammatory or foreign body reactions of the host tissues in contact with tricalcium silicate-based materials after different observation periods despite the identification of bacteria in dentinal tubules close to the site of operation. Wound healing was rapid with repair/regeneration of lost tissues with cementum and new bone trabeculae. Although the level of evidence for a case series is low because of the anecdotal nature of the reported episodes, the histologic results reported in the present case series illustrate the highly biocompatible and bioactive nature of the tricalcium silicate-based materials used in treating these cases.

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

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

Cellular response to mineral trioxide aggregate root-end filling materials.

Endodontic surgical procedures involve the use of a root-end filling material to provide an apical seal and to facilitate the repair and regeneration of periradicular tissues. Whereas earlier studies typically evaluated the cytotoxicity of these materials, contemporary research has focused on their capacity to support a favourable cellular response. In vitro tissue culture techniques have demonstrated interactions at the cell surface that may be conducive to periapical healing. Recent research with osteoblasts has confirmed their affinity for novel endodontic mineral trioxide aggregate (MTA) materials, with evidence of cell attachment and synthesis of bone matrix. This article reviews the current state of knowledge about MTA as a root-end filling material, with particular emphasis on cellular response to MTA materials.

Effect of calcium hydroxide-based materials on periapical tissue healing and orthodontic root resorption of endodontically treated teeth in dogs.

This study evaluated periapical tissue healing and orthodontic root resorption of endodontically treated teeth sealed with calcium hydroxide in dogs. The sample consisted of three contralateral pairs of maxillary incisors and two contralateral pairs of mandibular incisors in each of two dogs using a split mouth design. After biomechanical preparation of the teeth in the first group (n = 10), a Ca(OH)(2) dressing was placed for 14 days before root canal filling with Ca(OH)(2)-based sealer (Sealapex) and gutta-percha points. In the second group (n = 10), root canals were obturated immediately after the mechanical preparation with gutta-percha points and zinc oxide and eugenol (ZOE)-based sealer (Endofill). After completion of endodontic treatment, the teeth were moved with an orthodontic appliance with a calibrated force of 200 g, reactivated every 21 days. After 105 days, the animals were killed and the teeth were removed upon completion of active treatment, without a period of recovery, and prepared for histomorphological analysis. All sections of each tooth were graded subjectively on a scale from one to four to obtain the average of the 16 histomorphological parameters analysed. Evaluation of the differences between the two treatment protocols was made with Mann-Whitney U-test. It was observed that the teeth treated with Ca(OH)(2)-based materials provided better outcomes (P = 5%), with complete repair of all root resorption areas, high rate of biological closure of the main canal and apical accessory canals by newly formed cementum, less intense and extensive chronic inflammatory infiltrate, and better organization of the periodontal ligament. Under the tested conditions, Ca(OH)(2)-based materials had a favourable action on periapical tissue healing and repair of orthodontic root resorption in endodontically treated dogs' teeth.

Inadvertent injection of sodium hypochlorite into the periradicular tissues during root canal treatment.

This paper describes a sodium hypochlorite (NaOCl) incident occurring during routine endodontic treatment of a patient who presented with chronic periapical periodontitis of a maxillary canine tooth and discusses the immediate and late treatment of this case.

Bioactive tri/dicalcium silicate cements for treatment of pulpal and periapical tissues.

Over 2500 articles and 200 reviews have been published on the bioactive tri/dicalcium silicate dental materials. The indications have expanded since their introduction in the 1990s from endodontic restorative and pulpal treatments to endodontic sealing and obturation. Bioactive ceramics, based on tri/dicalcium silicate cements, are now an indispensable part of the contemporary dental armamentarium for specialists including endodontists, pediatric dentists, oral surgeons andfor general dentists. This review emphasizes research on how these materials have conformed to international standards for dental materials ranging from biocompatibility (ISO 7405) to conformance as root canal sealers (ISO 6876). Potential future developments of alternative hydraulic materials were included. This review provides accurate materials science information on these important materials. STATEMENT OF SIGNIFICANCE: The broadening indications and the proliferation of tri/dicalcium silicate-based products make this relatively new dental material important for all dentists and biomaterials scientists. Presenting the variations in compositions, properties, indications and clinical performance enable clinicians to choose the material most suitable for their cases. Researchers may expand their bioactive investigations to further validate and improve materials and outcomes.