Effects of N-acetyl-L-cysteine against apical periodontitis in rats with adriamycin-induced cardiomyopathy and nephropathy.

AIM: This study aimed to investigate the potential protective effects of N-acetyl-L-cysteine (NAC) against apical periodontitis (AP) in rats with adriamycin (ADR)-induced kidney and heart diseases. METHODOLOGY: Fourty-eight Wistar albino rats were divided into six groups: (1) Control group, (2) ADR group (1 mg/kg/day ip for 10 days), (3) AP Group (1st mandibular molar tooth), (4) AP + ADR Group, (5) AP + NAC group (150 mg/kg/day ip), and (6) AP + ADR + NAC group. After 3 weeks, the rats were decapitated and blood and tissue samples (heart, kidney, and jaw) were collected. Tissue samples were evaluated by biochemical (inflammatory cytokines and hemodynamic parameters) and radiological analyses. One-way anova with Tukey post hoc tests was used to compare data, considering p < .05 as statistically significant. RESULTS: The serum levels of TNF-α, IL-1ß, BUN, Creatinine, CK, and LDH were elevated in the test groups compared with the control group, and treatment with NAC reduced these levels (p < .05). Heart and kidney tissue analysis showed a higher heart-to-body weight ratio (HW/BW) and kidney-to-body weight ratio (KW/BW) in the test groups compared with the control group (p < .05). No significant differences in HW/BW and KW/BW were found between the control and AP + NAC groups. Volumetric apical bone resorption analysis showed an increase in periapical radiolucencies in AP-induced groups indicating apical periodontitis. NAC treatment reduced the total area and volume of resorption cavities (p < .05). CONCLUSIONS: The results suggest that NAC's antioxidant and anti-inflammatory effects can reduce adriamycin-mediated heart and kidney damage and may have a positive effect on apical periodontitis in individuals with nephropathy and cardiomyopathy.

A Follicle-Stimulating Hormone Exacerbates the Progression of Periapical Inflammation Through Modulating the Cytokine Release in Periodontal Tissue.

Menopause is directly related to a systemically low grade of inflammation, indicating that postmenopausal women might be more prone to the development of inflammation. The high levels of circulating follicle-stimulating hormone (FSH) may cause hypogonadal bone loss during postmenopausal osteoporosis independent of estrogen. Previous research revealed that FSH could aggravate alveolar bone loss during experimental periapical lesions in ovariectomized rats; however, the mechanisms for these effects remain unclear. In this study, we showed that FSH enhanced the expression and secretion of the proinflammatory cytokines interleukin (IL)-1ß, IL-6, and tumor necrosis factor alpha to a significant degree in human periodontal ligament (hPDL) cells. Furthermore, FSH upregulated Porphyromonas gingivalis lipopolysaccharide (pg LPS)-induced proinflammatory cytokine production. Furthermore, in vivo studies demonstrated that FSH increased the levels of the aforementioned cytokines in the serum and enhanced the expression of Toll-like receptor 4 at both the messenger RNA and protein levels in hPDL cells and periodontal tissues. Our research suggests that high FSH levels may regulate the immune status of periodontal tissues during the postmenopausal period and, to a certain extent, suggested that postmenopausal women might be more prone to the development of inflammation of the periapical periodontitis and more obvious bone loss.

Inducing Apical Periodontitis in Mice.

The mechanisms involved in local induced inflammation can be studied using several available animal models. One of these is the induction of apical periodontitis (AP). Apical periodontitis is a common pathology of an inflammatory nature in the periodontal tissues surrounding the tooth root. In order to better understand the nature and mechanism of this pathology it is advantageous to perform the procedure in mice. The induction of this odontogenic inflammation is achieved by drilling into the mouse tooth until the dental pulp is exposed. Next, the tooth pulp remains exposed to be contaminated by the natural oral flora over time, causing apical periodontitis. After this time period, the animal is sacrificed, and the tooth and the jaw bone can be analyzed in various ways. Typical analyses include micro-CT imaging (to evaluate bone resorption), histological staining, immunohistochemistry, and RNA expression. This protocol is useful for research in the field of oral biology to better understand this inflammatory process in an in vivo experimental setting with uniform conditions. The procedure requires a careful handling of the mice and the isolated jaw, and a visual demonstration of the technique is useful. All technical aspects of the procedures leading to induced apical periodontitis and its characterization in a mouse model are demonstrated.

Salivary opiorphin in dental pain: A potential biomarker for dental disease.

OBJECTIVES: Opiorphin is a recently discovered peptide shown to inhibit the enkephalin-degrading enzymes and prolong the effects of enkephalins. Although opiorphin is found in high concentrations in saliva, the relationship between salivary opiorphin and orofacial pains is not yet fully understood. We aimed to determine salivary opiorphin concentrations in dental pain related to symptomatic irreversible pulpitis (SIP), and symptomatic apical periodontitis (SAP). DESIGN: 39 patients participated in this study. The participants were categorized into SIP and SAP based on their diagnosis. All the patients were treated with root canal treatment. Saliva specimens were collected, and pain levels were recorded at pre-treatment, 7 days post-treatment and 30 days post-treatment. Saliva opiorphin levels were measured using a commercially available ELISA kit. Pre-treatment and post-treatment opiorphin levels were evaluated using repeated measures ANOVA. Correlations between VAS scores, opiorphin levels and age were evaluated using Spearman's Rank Correlation. RESULTS: The average saliva opiorphin level pre-treatment, 7 days post-treatment and 30 days post-treatment were 31.28 ± 7.10 ng/ml, 20.41 ± 2.67 ng/ml and 18.61 ± 2.05 ng/ml respectively. Significantly higher pre-treatment opiorphin levels were observed in the SIP group compared to the SAP group. A strong correlation was observed between the pre-treatment pain levels and the saliva opiorphin concentrations. CONCLUSIONS: Our findings indicate that saliva opiorphin levels increase in inflammation related dental pain. The level of salivary opiorphin is strongly correlated with the reported level of pain. The extent of the inflammation (pulpal vs. periodontal) also affects the opiorphin level.

Capsaicin-sensitive Innervation Modulates the Development of Apical Periodontitis.

INTRODUCTION: Nociceptive neurons play a critical role in the detection of stimuli evoking actual or potential tissue injury. In addition, they are involved in neurogenic inflammation by the peripheral release of neuropeptides such as calcitonin gene-related peptide (CGRP). The dental pulp and periradicular tissues are innervated by capsaicin-sensitive neurons known to release CGRP. However, the role of these capsaicin-sensitive neurons in the development of apical periodontitis is largely unknown. The aim of this study was to evaluate the contribution of peptidergic neurons to the development of apical periodontitis. METHODS: Neonatal Sprague-Dawley rats were injected with vehicle (control group) or a single subcutaneous capsaicin dose to cause the selective ablation of peptidergic neurons (neonatal capsaicin group). Ablation of capsaicin-sensitive neurons was verified with confocal microscopy, capsaicin-induced eye-wipe nocifensive behavior test, and by measurement of immunoreactive CGRP levels in the dental pulp. Five weeks after ablation, standardized pulp exposures were made in the mandibular left first molars. Mandibles were harvested at 7, 14, 21, and 28 days after pulp exposure and imaged with micro-computed tomography (µCT) to quantify apical lesion volume. Data were analyzed by using 2-way ANOVA analysis with Bonferroni post hoc test. RESULTS: Rats in the control group displayed a robust capsaicin-induced nocifensive behavior, which was nearly abolished in the neonatal capsaicin group. In addition, the neonatal capsaicin group showed a significant depletion of susceptible neurons and CGRP in the dental pulp compared with control. Importantly, micro-computed tomography analysis showed larger periradicular lesions at 7 and 14 days after pulp exposure in the neonatal capsaicin group when compared with control. CONCLUSIONS: Results identify a protective role for capsaicin-sensitive neurons in the initial phase of apical periodontitis. Thus, interventions or disorders that alter activity of capsaicin-sensitive fibers are likely to alter the development of apical periodontitis.

Cemento-osseous dysplasia in an elderly Asian male: a case report.

Cemento-osseous dysplasia is a disorder typically found in middle-aged black women. However, the present report describes a case in a 61-year-old Vietnamese male. Without proper pulp testing and diagnosis, the radiographic presentation can easily be misdiagnosed as periapical periodontitis. On the basis of pulp vitality, lack of clinical symptoms and radiographic features, the diagnosis in this case was periapical cemento-osseous dysplasia at the mixed stage, which generally requires no treatment. At the 18-month follow-up, the patient was still asymptomatic and none of the clinical signs had changed. This case highlights the importance of careful clinical examination, including a pulp vitality test, and of having an unbiased view of age, gender, and ethnicity when diagnosing this condition.

A biocompatible model for evaluation of the responses of rat periapical tissue to a new zinc oxide-eugenol sealer.

We aimed to establish an experimental animal model to evaluate materials for endodontic therapy. We focused on the biocompatibility of new paste-type zinc oxide-eugenol (ZOE) sealer. The results of this sealer were compared with those of conventional powder/liquid ZOE and eugenol-free sealers. The molars of Wistar rats were extracted and repositioned in the original socket after application of the sealers on the root apices. Mild inflammation occurred in the periapical tissue of the replanted teeth with both ZOE sealers on day 7, whereas the eugenol-free sealer induced severe inflammation. On day 14, the lesions induced by all types of sealers were healed and replaced predominantly by fibrous connective tissue. Thus, all endodontic materials showed high biocompatibility, although the extent of inflammatory reactions during the early stages varied depending on the types of materials. We demonstrated that our animal model was useful for the assessment of the biocompatibility of endodontic materials.

Response of the periapical tissue of dogs' teeth to the action of citric acid and EDTA.

The purpose of this study was to analyze the inflammatory response of dog's periapical tissues to 17% trisodium EDTA salt (pH 8.0) and 1% citric acid (pH 2.0). Saline was used as a control. Six adult dogs were used as the biological model of the study. The experimental units comprised 56 roots of mandibular molars (first and second) and premolars (first, second and third). After coronal opening, pulpectomy and root canal instrumentation were performed using the above-mentioned irrigating solutions. After 24 and 48 hours, the animals were euthanized and the teeth and their supporting tissues were removed and histologically processed. The sections were stained with hematoxylin and eosin and analyzed histopathologically with a light microscope at x100 magnification. The histological analysis focused on the occurrence of acute inflammatory response. The presence of swelling, vasodilatation and inflammatory cells were evaluated and the degree of inflammation was determined for each case. Data were analyzed by Fisher's exact test using the SPSS software with a confidence interval of 95% (p<0.05). 17% EDTA and 1% citric acid caused inflammatory responses in dog's periapical tissues with no significant differences to each other or to saline (control) at either the 24-hour (p=0.482) or 48-hour (p=0.377) periods. It may be concluded that the inflammatory response was of mild intensity for the tested substances.

Response of the periapical tissue of dogs' teeth to the action of citric acid and EDTA

The purpose of this study was to analyze the inflammatory response of dog's periapical tissues to 17 percent trisodium EDTA salt (pH 8.0) and 1 percent citric acid (pH 2.0). Saline was used as a control. Six adult dogs were used as the biological model of the study. The experimental units comprised 56 roots of mandibular molars (first and second) and premolars (first, second and third). After coronal opening, pulpectomy and root canal instrumentation were performed using the above-mentioned irrigating solutions. After 24 and 48 hours, the animals were euthanized and the teeth and their supporting tissues were removed and histologically processed. The sections were stained with hematoxylin and eosin and analyzed histopathologically with a light microscope at x100 magnification. The histological analysis focused on the occurrence of acute inflammatory response. The presence of swelling, vasodilatation and inflammatory cells were evaluated and the degree of inflammation was determined for each case. Data were analyzed by Fisher's exact test using the SPSS software with a confidence interval of 95 percent (p<0.05). 17 percent EDTA and 1 percent citric acid caused inflammatory responses in dog's periapical tissues with no significant differences to each other or to saline (control) at either the 24-hour (p=0.482) or 48-hour (p=0.377) periods. It may be concluded that the inflammatory response was of mild intensity for the tested substances.

Histological evaluation of MTA as a root-end filling material.

AIM: To assess the histological response associated with grey mineral trioxide aggregate (GMTA) and zinc oxide eugenol (ZOE) as root-end filling materials in teeth where the root canals were not filled and the coronal access cavities were not restored. METHODOLOGY: Periapical lesions were developed in 24 premolar teeth in three dogs. The root canals were prepared and half of them were dried, filled and the coronal access restored (closed). The remaining teeth were not root filled and no coronal restoration was placed (open). Apical root-end resections were performed 3 mm from the apex, and root-end cavities were prepared with ultrasonic tips. These were randomly filled with either ZOE or GMTA in the same number of specimens using MAPSYSTEM device. After 180 days the animals were killed and blocks of tissues removed and processed for histological examination. Periradicular tissue reaction was evaluated, including severity of inflammation and cementum formation. Statistical analysis was performed using anova analysis and Tukey's test. RESULTS: A significant difference was found between the levels of inflammation in the periradicular tissues of the GMTA/closed group, compared with the ZOE/open and ZOE/closed groups (P < 0.05) but not between GMTA/closed and GMTA/open groups. Cementum formation was not found over any ZOE specimens but over MTA in all specimens. No microorganisms were found in the interface between the material and the dentinal walls. CONCLUSIONS: GMTA was associated with less periapical inflammation and tissue response when used as a root-end filling material, even when no root filling or coronal restoration was present.

[Expression of lipopolysaccharide receptors CD14 and TLR4 in a model of rat molar apical periodontitis].

OBJECTIVE: To characterize the expression of lipopolysaccharide (LPS) receptors-CD14 and TLR4 in rat peri-radicular tissue and to investigate the signal transduction pathway of LPS and its receptors in periapical periodontitis. METHODS: After establishment of a model of rat molar LPS-induced apical periodontitis, CD14 and TLR4 expression in healthy and inflammatory periapical tissue were determined by immunohistochemistry. RESULTS: CD14 and TLR4 were not detected in healthy periapical tissue but strongly positive in inflammatory periapical tissue. Positive cells were mostly monocytes/macrophages. CONCLUSIONS: CD14 and TLR4 may play an important role in the pathogenesis of periapical periodontitis, probably via immune cells such as monocytes/macrophages and neutrophils.

[Animal test of nHA-PA66 used in root canal filling].

OBJECTIVE: To assess the dogs' tissue reaction to nHA-PA66 which is prepared to be used as a new root canal filling sealer. METHODS: The experimental apical periodontitis of dogs was induced first, then nHA-PA66 was used in the test groups while CCQ was used in the control group. The reactions of periapical tissues were measured by histological means. RESULTS: One month after nHA-PA66 was used in root canal filling, the dogs' periapical tissues showed mild to moderate inflammatory reactions, the X-ray films showed decreased radiolucent area as compared with the previous film. Three months later, tissue repairs occurred, which exhibited even more decreased radiolucent area on X-ray films. nHA-PA66 caused weak inflammatory reaction while the reparative reaction happened early. CONCLUSION: nHA-PA66 has good tissue compatibility and is a potential sealer for root filling in clinical use.

Tissue reaction initiated by different sealers.

AIMS: To analyse the type and degree of inflammatory reaction initiated by four sealers. METHODOLOGY: Twenty-four root canals of Macaca mulatta monkeys were filled within the canal and eight were overfilled with AH26, Apexit, Endomethasone or Grossman's sealers. The result of the treatment was evaluated after 6 months by histological assessment of the periapical tissues. RESULTS: In the group of root canals filled within the root, no inflammatory reaction was detected in specimens of Apexit and Grossman's sealers, but the other two sealers initiated different degrees of lymphocytic/plasmocytic tissue reactions. Endomethasone initiated a mild lymphocytic/plasmocytic reaction in three of the nine cases and AH26 caused mild lymphocytic/plasmocytic infiltration in two of the seven cases. In the group of overfilled root canals, all four sealers initiated inflammatory reactions. The periapical tissue reactions of overfilled root canals were similar to reactions detected in cases filled within the canal. However, additional histological features developed in specimens of Endomethasone and AH26: Endomethasone initiated a foreign body-type granulomatous reaction around the sealer particles and AH26 particles were engulfed by macrophages. The overfilled root canals of Apexit and Grossman's sealers initiated only lymphocytic/plasmocytic reactions. CONCLUSIONS: This study suggests that sealers with different chemical compositions initiate different histological reactions. It also emphasizes the importance of confining root filling to the canal system because all sealers initiate inflammatory reactions when they are present in the apical tissues

Avaliaçäo histomicrobiológica após curativo de demora com pastas à base de hidróxido de cálcio por diferentes períodos de tempo / Histomicrobiologic evaluation after intracanal dressing with pastes based on calcium hydroxide in different periods of time

O objetivo deste trabalho foi avaliar o efeito antimicrobiano da pasta à base de hidróxido de cálcio empregada como curativo de demora em pré-molares de cäes com lesäo periapical crônica, sendo utilizados 80 canais radiculares. Após comprovaçäo radiográfica da formaçäo de lesöes periapicais induzidas e preparo biomecânico, os canais radiculares foram preenchidos com pasta à base de hidróxido de cálcio associada ao p-monoclorofenol canforado (Calen-PMCC). Decorridos os períodos de 7, 15 e 30 dias, os animais foram sacrificados e os cortes histológicos obtidos corados pelo método de Brown&Bren. O resultado da avaliaçäo histomicrobiológica demonstrou maior efeito antimicrobiano no período de 30 dias. O período de 15 dias apresentou melhores resultados quando comparado ao de sete dias

Tissue response to an epoxy resin-based root canal sealer.

The objective of the present study was to evaluate two different types of root canal sealers: AH Plus (an epoxy resin-based sealer) and Fill Canal (a zinc oxide-eugenol based sealer). A total of 34 root canals with vital pulp from dogs' premolars were used. After instrumentation, the root canals were filled with gutta-percha and AH Plus or gutta-percha and Fill Canal sealers using a classical technique of lateral condensation. After histological processing, the sections were stained with hematoxylineosin or Mallory's trichrome stain. Inflammatory cells or areas of necrosis were not associated with AH Plus. Hard tissue formation apically to the material was observed in 14 specimens. The Fill Canal sealer presented an inflammatory response of moderate intensity in the periapical region, mainly adjacent to the material.

Histological evaluation of the response of apical tissues to glass ionomer and zinc oxide-eugenol based sealers in dog teeth after root canal treatment.

The object of the study was to compare two commercial root canal sealers: Ketac-Endo (a glass ionomer cement) and Fill Canal (a zinc oxide-eugenol cement). A total of 34 root canals from dog premolars with vital pulps were used. After instrumentation, the root canals were sealed with Ketac-Endo and Fill Canal cements using gutta-percha and a lateral condensation technique. After 270 days the animals were sacrificed with an anesthetic overdose and the maxillae and mandibles were removed and fixed in formalin for 48 h. After routine histological processing the sections were stained with hematoxylin-eosin and Mallory trichrome stains. Microscopic analysis revealed that Ketac-Endo cement presented better results than Fill Canal cement.

Effect of various sealers with gutta-percha as root-end fillings on healing after replantation.

This study examined histologically the effect of three sealers used with gutta-percha as root-end fillings placed in a replantation model. A total of 14 molar teeth were used in seven monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared, and fillings of gutta-percha and sealer placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Six roots filled with gutta-percha plus a fortified zinc oxide-eugenol cement (IRM), 13 with gutta-percha plus zinc oxide-eugenol (EP), and eight with gutta-percha plus Kloropercha, were available for examination. The tissue response to gutta-percha with either zinc oxide material was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed against root ends filled with gutta-percha and Kloropercha. Gutta-percha plus IRM or zinc oxide-eugenol had a much more favourable response than that to amalgam reported previously in a similar experiment.

Effect of various zinc oxide materials as root-end fillings on healing after replantation.

This study examined the effect of various zinc oxide materials as root-end fillings of teeth in a replantation model. A total of 35 molar teeth were used from 19 monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared and fillings placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Twelve roots were filled with IRM plus dentine chips, and six with Cavit; the tissue response around root ends filled with these materials as assessed by inflammation was similar to that previous reported to IRM and Super EBA cement and was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed around root ends filled with plain zinc oxide-eugenol or Kalzinol; however, the reaction was neither as severe nor as extensive as that to amalgam root-end fillings. Giant cells were observed most often on the surface of fillings with Cavit and zinc oxide-eugenol. It is concluded that the tissue response to IRM with or without added dentine, Super EBA and Cavit was similar and mild; it was less severe than that to zinc oxide-eugenol and Kalzinol. All these materials had a much more favourable response than amalgam

A histological comparison of periapical inflammatory and neural responses to two endodontic sealers in the ferret.

Previous studies have shown that there is a proliferation of nerves beneath the apices of pulpectomized teeth. This may be due to the inflammation induced after the procedure, resulting, perhaps, from the irritant nature of the materials used to fill the root canal. The experiment reported here was conducted to determine whether this inflammation was induced by the sealer rather than arising as a result of tissue damage and whether, if inflammation is eliminated or reduced, the neural changes are also reduced. In 12 young adult ferrets under general anaesthesia the pulps of the lower canine teeth were removed and replaced with gutta percha and sealer. A sealer of Grossman's formulation with eugenol as the liquid phase was used on one side and a calcium hydroxide sealer that contained no eugenol on the other. Three months later the animals were, again under general anaesthesia, perfused with a fixative mixture. The mandibles were removed and the presence and size of any periapical inflammatory lesions and the density of periapical innervation determined histologically. All 12 teeth sealed with the Grossman's sealer had inflammatory lesions at their apices. Three of the 12 teeth treated with the calcium hydroxide sealer showed similar lesions. In all the teeth with inflammatory lesions the normal arrangement of nerves in a periodontal 'plexus' was disrupted but there was no statistically significant difference between the overall innervation density in inflamed and non-inflamed periapical areas nor between areas beneath teeth sealed with Grossman's sealer and with calcium hydroxide. The incidence of periapical inflammation is related to the nature of endodontic sealer used.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue reactions to endodontic materials implanted in the mandibles of guinea pigs.

Teflon, Intermediate Restorative Material, and Prisma VLC Dycal were implanted in the mandibles of 16 guinea pigs. After experimental periods of 4 and 12 weeks, the animals were killed and tissue sections were prepared. No severe inflammatory response was noted in any of the groups except for a persistence of moderate inflammation in the poorly condensed Teflon group. Bone apposition occurred in the Prisma VLC Dycal group; none-to-mild inflammation and a thin fibrous capsule characterized the IRM group; and the Teflon group had a thick fibrous encapsulation except for samples where the Teflon material appeared to be poorly condensed and dispersed into the bony tissue. In areas where the teflon was loosely condensed, chronic inflammation and active phagocytosis were seen along the surface of the material.