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A new root canal sealer based on calcium hydroxide.

A new root canal sealer based on calcium hydroxide has been developed and two properties, sealing ability and biocompatibility, have been investigated in this study. Sealing ability was assessed by the extent of dye penetration along root fillings in extracted teeth. The sealing ability was good and similar to that of a control zinc oxide-eugenol sealer. Biocompatibility was assessed by histological examination of the periapical tissues of monkey teeth, either 1 or 6 months, after vital pulpectomy and immediate root filling with gutta-percha and sealer. Zinc oxide-eugenol was used as the control sealer. Normal periapical tissues were observed around all 24 teeth filled with the experimental root canal sealer. The study established that the new root canal sealer had acceptable properties of biocompatibility and sealing ability.

Animals↗

[Study on the sealing capability of a calcium phosphate root canal filling material].

To evaluate the sealing potential of self-designed root canal filling material made of calcium phosphate cement (alpha-TCP/TTCP, CPC), the apices of root canals of six adult dogs were purposely perforated and enlarged up to the No 40 instrument. Then CPC was used to fill the root canal. Mean while either calcium hydroxide (Ca(OH)2) paste or hydroxyapatite (HA) paste was used as control. The animals were killed at 4, 12, 20 weeks postoperatively. The different materials about ways of apical closure, restoration periapocal tissues and adaptability to the dentinal surface were observed by histomorphology and scanning electron microscopic. This study revealed that CPC had excellent biocompatibility and adaptability to the dentinal wall. Its osteoconduction can promote the formation of calcific barriers and healing of periapical tissue. The apex can be closed completely. Compared with the control pastes it has advantages of ease of manipulation and better sealing capability. The results showed that CPC could be used as a root canal filling material for pupless teeth with open apex and destructive periapical tissue.

Animals↗

On the causes of persistent apical periodontitis: a review.

Apical periodontitis is a chronic inflammatory disorder of periradicular tissues caused by aetiological agents of endodontic origin. Persistent apical periodontitis occurs when root canal treatment of apical periodontitis has not adequately eliminated intraradicular infection. Problems that lead to persistent apical periodontitis include: inadequate aseptic control, poor access cavity design, missed canals, inadequate instrumentation, debridement and leaking temporary or permanent restorations. Even when the most stringent procedures are followed, apical periodontitis may still persist as asymptomatic radiolucencies, because of the complexity of the root canal system formed by the main and accessory canals, their ramifications and anastomoses where residual infection can persist. Further, there are extraradicular factors -- located within the inflamed periapical tissue -- that can interfere with post-treatment healing of apical periodontitis. The causes of apical periodontitis persisting after root canal treatment have not been well characterized. During the 1990s, a series of investigations have shown that there are six biological factors that lead to asymptomatic radiolucencies persisting after root canal treatment. These are: (i) intraradicular infection persisting in the complex apical root canal system; (ii) extraradicular infection, generally in the form of periapical actinomycosis; (iii) extruded root canal filling or other exogenous materials that cause a foreign body reaction; (iv) accumulation of endogenous cholesterol crystals that irritate periapical tissues; (v) true cystic lesions, and (vi) scar tissue healing of the lesion. This article provides a comprehensive overview of the causative factors of non-resolving periapical lesions that are seen as asymptomatic radiolucencies post-treatment.

Actinomycosis↗

[Aplication of magnetostimulation in JPS system of chronic periapical tooth inflamation visible in the RTG picture].

PURPOSE: The aim of the work was to use the magneto-stimulation in JPS system as a therapy aiding the treatment of chronic inflammation of periapical tissues of a tooth and to evaluate its effectiveness in RTG in Digora 2.1 digital system and in conventional RTG. MATERIAL AND METHODS: The research was based on 62 teeth of 56 people (some treated for the first time). There was also a comparative group. In the work the magnetic field was used since the first day ofendodental treatment. Every patient had RTG done before and after the magnetostimula-tion. The qualitative and quantitative evaluations were done. The optical density both in the area of the osteolisis and in the laudable bone was presented in tables and graphs. The statistical analysis was also done. Conventional RTG was also used to evaluate the research. CONCLUSION: It was ascertained that magnetic field of low induction has a positive effect on the regeneration processes in chronic inflammations of periapical tissues of the tooth, visible in RTG.

Absorptiometry, Photon↗

[Dental pain].

"The extreme variability of toothache is such that a good rule for any examiner is to consider all pains about the mouth and face to be of dental origin until provide otherwise" (Welden E. Bell). Dental caries is a disease of the calcified tissues of the teeth, characterised by demineralization of the inorganic portion and destruction of the organic substance of the tooth. The acids which affects the primary decalcifications is derived from the fermentation of starches and sugar logged in the retaining centers of the teeth. Dental caries can be classified in relation with the depth of the lesions: caries of the enamel, caries of the dentin, pulp diseases which are the result of dental caries in which bacterial invasion of the dentin and pulp tissue occurs, diseases of the periapical tissues which leads to periapical cyst, or to periapical abcess.

Acute Disease↗

Pretreatment strategies for infection prevention in chemotherapy patients.

It is important to understand the pathogenesis of acute oral infections in patients with chemotherapy-induced myelosuppression in order to develop strategies to prevent such complications. Four distinct oral sites that can either be acutely infected or contribute to acute systemic infection are the oral mucosa, dental pulp and periapical tissues, periodontium, and salivary glands. Many cytotoxic drugs can be directly stomatotoxic to replicating oral mucosa. Once mucosal integrity is affected, secondary acute infection can occur. Even without clinical ulceration, deleterious shifts in the oral microbial population can develop. Gram-negative bacilli have been identified as frequent colonizers of myelosuppressed patients, although coagulase-negative staphylococci are being recovered with increasing frequency. Strategies to prevent oral mucosal infection include reducing trauma and preventing proliferation of organisms. Dental pulpal infection is most commonly caused by extensive dental caries. Most pulpal infection is of bacterial origin and can progress to involve the periapical tissues of the involved tooth if not treated. Specific endodontic interventions will usually stabilize or eliminate the source of the infection until the patient's hematologic status returns to normal and definitive pulpal therapy can be provided. In part because acute pulpal complications in the myelosuppressed cancer patient are relatively infrequent, research on the causative organisms and the appropriate therapy of acute, systemic infection of pulpal origin has been limited. Many adults have chronic, asymptomatic periodontal disease. In its advanced stages, extensive ulceration may be present that is not clinically observable. In patients with reduced host defenses, exacerbation of preexistent periodontal disease can have systemic sequelae and is associated with elevated levels of periodontopathic organisms or pathogens typically associated with systemic infection in myelosuppressed cancer patients. Mechanical and chemical antimicrobial techniques are available to reduce prevalence and improve patient comfort and oral hygiene. Dental extractions may be indicated to eliminate the nidus of infection of either pulpal or periodontal origin in patients who are scheduled to receive myelosuppressive chemotherapy. Data indicate that such procedures may be performed without undue risk. Unlike patients who undergo bone marrow transplantation or radiotherapy, patients who receive chemotherapy do not commonly experience subjective salivary gland dysfunction. Occasionally, a transient xerostomia may occur; this condition is frequently attributed to the patient's oral habits, such as breathing through the mouth. The dessicating effect of breathing through the mouth can contribute to oral mucosal injury during function as well as provide a setting for acute infection of commensal origin. More research is needed on the effects of chemotherapy on salivary host defenses.

Antineoplastic Agents↗

Apical diffusion of calcium hydroxide in an in vitro model.

An in vitro agar model was developed to study the effect of intracanal medicaments on periapical tissues and was used to study the diffusion of three calcium hydroxide (Ca(OH)2) medicaments of varying viscosity through simulated root canals with various sizes of apical foramina. Experimental medicaments were added to pipette tips used to represent tooth roots, which were fixed in syringes containing brain heart infusion agar and calcium-reactive dye. OH and Ca concentrations were measured in the agar at 30 minutes and 24 hours. Ca concentration and pH increased with larger aperture sizes, and higher pH and Ca diffusion was produced by a 10% Ca(OH)2 solution than was produced by Pulpdent or a Ca(OH)2 paste. The results suggest that the properties of the Ca(OH)2-containing vehicle could affect the action of the medicament in the periapical tissues.

Analysis of Variance↗

Intrusion injuries of primary incisors. Part II: Sequelae affecting the intruded primary incisors.

Luxation injuries to incisors, including intrusive displacement, occur with a high frequency in the primary dentition. Intrusion injuries are associated with damage to the pulpal and periodontal structures and possible fracture of the alveolar bone. The pulpal tissue of the intruded tooth sustains a severe shock during displacement, which may be reflected later by sequelae ranging from mild discoloration to pulpal necrosis and infection. Disintegration of pulpal tissue may result in periapical tissue inflammation, which in turn may induce developmental disturbances in the germ of the permanent successor tooth. Additionally, severe injury to the periodontal ligament during intrusion may lead to ankylosis of the primary incisor and consequently to delayed or ectopic eruption of its permanent successor. This article will review the possible sequelae affecting primary incisors following their intrusion.

Alveolar Process↗

Steroids reduce the periapical inflammatory and neural changes after pulpectomy.

Root canal treatment, including obturation with gutta-percha and a zinc oxide and eugenol sealer, was conducted, under general anesthesia, on the canine teeth of 12 young ferrets. Six of the ferrets were given 0.5 mg/kg dexamethasone daily. Three months after the root canal treatment, under general anesthesia, the animals were perfused with fixative and the canine periapical tissues prepared for histological examination. The extent of periapical inflammation was measured and the degree of neural sprouting in the periodontal and subapical regions estimated. Periapical lesions in steroid-treated animals were 30% of the size of those in untreated animals. Innervation density in the subapical region of the steroid-treated animals was lower than that in the animals who did not receive steroids and not significantly different from controls. Reduction in periapical inflammation induced by systemic steroids is accompanied by a reduction in neural sprouting.

Animals↗

Detection of IgA subclasses and J chain mRNA bearing plasma cells in human dental periapical lesions by in situ hybridization.

Humoral immune responses are implicated in the pathogenesis of human dental periapical lesions. To elucidate whether IgA-associated immune systems play a role in the lesions, the in situ hybridization technique was used to detect J chain mRNA expression, which is correlated with the secretion of dimeric IgA. In addition, IgA subclass mRNA-expressing cells were also investigated by double target in situ hybridization (ISH) methodology using digoxigenin- and biotin-labeled IgA subclass specific oligonucleotide probes. This double target ISH technique involved immunochemical detection with an alkaline phosphatase-conjugated antibody and a peroxidase conjugated avidin-biotin complex system to detect IgA subclass mRNA in the formalin-fixed, paraffin wax embedded periapical tissue sections. Twenty-four biopsy samples (16 periapical granulomas and 8 radicular cysts) were examined. IgA subclass mRNA positive plasma cells were detected in all samples. IgA1 mRNA-expressing cells were predominant both in granulomas and cysts (mean = 75.3 +/- 11.2%, 64.8 +/- 21.3%, respectively), and the IgA1 proportion was higher in granulomas than in cysts, although no significant difference was seen between the two lesions (p = 0.132). J chain mRNA positive cells were very sparsely detected in 21/24 cases. The median percentages of J chain mRNA positive cells/IgA mRNA positive plasma cells (4.7%, range 0.3-13.6%) in cysts were significantly higher than in granulomas (1.3%, range 0-7.7%; p = 0.03). This result supports the hypothesis that dimeric IgA may be more actively produced in radicular cysts than in granulomas. These features are thought to reflect the local activation of the periapical immune system in response to environmental factors and indicate that secretory IgA mediated immune defense systems appear to play little role in these lesions. Our results indicate that the IgA-associated immune response in periapical lesions is more similar to serum or systemic IgA responses than to mucosa-associated immune responses where dimeric IgA predominates.

Adult↗

Periapical diseases: spectrum and differentiating features.

There are a variety of lesions besides the typical granulomas and cysts that can appear at the apices of teeth. These other lesions must receive consideration in the diagnosis of periapical disease because of their potential impact on patient treatment and outcome. This paper will review the spectrum of diseases that may present in periapical tissues, the pathogenesis, of periapical inflammatory disease, and the signs and symptoms that separate periapical inflammatory disease from neoplastic disease.

Diagnosis, Differential↗

Apical hard-tissue deposition in adult teeth of monkeys with use of calcium hydroxide.

The periapical tissues of adult teeth of monkeys were examined histologically after root canal treatment with calcium hydroxide. Healing, as evidenced by complete apical closure with a hard tissue bridge and an inflammation-free periodontal ligament, occurred more frequently where canals were instrumented 1 mm short of the apex. Overinstrumented canals exhibited a significantly decreased incidence of apical closure.

Animals↗

A histopathologic, histobacteriologic, and radiographic study of periapical endodontic surgical specimens.

Data available on 230 periapical endodontic surgical specimens were studied. It was found that bacteria occurred in the periapical tissue very infrequently. In addition, there was no correlation between the presence of acute inflammatory cells and the presence or absence of pain. Granulomas with epithelium occurred in 61 out of 230 cases, while 14 of these were cysts. Of the 110 cases with radiographic follow-up data, 67 were classified as successful, 40 were uncertain, and 3 were unsuccessful according to a modification of Strindberg's criteria, whereas 107 would have been successes according to the criteria of Bender and Seltzer and their associates. No valid biologic or clinical basis for endodontic therapy as suggested by Bhaskar was found in this material.

Connective Tissue↗

Production of human-inducible nitric oxide synthase in radicular cysts.

To examine if nitric oxide (NO) is produced in radicular cysts, NO synthase (NOS) production was analyzed. Periapical tissues were removed from patients at the time of endodontic surgery. Frozen tissue sections were histologically evaluated with hematoxylin-eosin staining. Production of human-inducible NOS (iNOS) in apical cysts was then immunohistochemically examined. Immunoreactive human iNOS was widely distributed in epithelial cells, endothelial cells, fibroblasts, macrophages, or polymorphonuclear leukocytes. Remarkably, iNOS-positive cells were significantly present around blood vessels, and cells residing apart from the blood vessels showed weak or no iNOS production, suggesting that only cells around blood vessels could be stimulated for iNOS synthesis. These data demonstrated the possibility that several, but not all, cells could be stimulated to synthesize iNOS in inflamed tissues. In the presence of iNOS, NO can be produced spontaneously in periapical lesions and may play a crucial role in the regulation of chronic infection.

Enzyme Induction↗

Detection of apoptosis during orthodontic tooth movement in rats.

Experimental evidence suggests that cellular changes and tissue turnover occurs in the periapical tissue during tooth movement. The possible role of apoptosis in tooth movement has never been investigated. The purpose of this study was to show whether apoptosis plays any role in orthodontic tooth movement. A sample of 21 adult male Sprague-Dawley rats was divided into 4 groups. Orthodontic appliances were attached to the rats for various times-to group I (n = 6) for 3 days, to group II (n = 6) for 1 week, and to group III (n = 6) for 2 weeks. Rats in group IV (n = 3) had appliances but no force and served as the control group. At the end of the observation period, the animals were killed and tissue blocks of involved teeth were processed and prepared for TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) reaction. TUNEL-positive cells from selected areas on each slide were counted and compared by means of an analysis of variance. Group I demonstrated a significantly higher (P <.05) number of positive cells. This suggests that the maximum apoptosis occurs approximately 3 days after the application of the appliance.

Alveolar Bone Loss↗

A prognostic model for assessment of the outcome of endodontic treatment: Effect of biologic and diagnostic variables.

OBJECTIVE: Many biological variables, endodontic treatment factors, and restorative considerations have been suggested in the literature to affect the outcome of endodontic treatment. However, few attempts have been made recently to study these variables further. The purpose of this study was to identify the biologic and endodontic treatment-associated variables that are most predictive of treatment outcome for conventional endodontic therapy and to determine the magnitude of risk these variables pose on the outcome. STUDY DESIGN: The population of this historical prospective cohort study comprised a total of 200 teeth with 441 root canals. Diagnostic and treatment information was abstracted from the original patient records. An endodontic follow-up examination was conducted 4 +/- 0.5 years after obturation. Each tooth/root was analyzed according to 3 indices of periradicular status at 2 time points. The main outcome measure was the presence of apical periodontitis. The criteria used for evaluation of the outcome were modified from Strindberg. Data were subjected to univariate and multivariate analysis. Logistic regression models were fit by using various clinical measures to determine which combination of biologic and treatment-associated factors best predicted treatment outcome. RESULTS: The preoperative pulp diagnosis, the periapical diagnosis, the preoperative periapical radiolucency size, and the sex of the patients were revealed, by means of univariate analysis, to exert a significant influence on endodontic treatment outcome (P <.05). In the logistic regression model, the strongest effect on postoperative healing was the presence and magnitude of preoperative apical periodontitis. In the presence of this variable, no other factor contributed value to the prediction. The correct prediction of this model was 74.7% (P <.05). CONCLUSION: The major biologic factors influencing the outcome of endodontic treatment appear to be the extent of microbiological insult to the pulp and periapical tissue, as reflected by the periapical diagnosis and the magnitude of periapical pathosis.

Acute Disease↗