Periapical Reactions Research Articles

Periapical repair action and antimicrobial activity through calcium hydroxide-based dressings: a comprehensive review

Introduction: Endodontic therapy aims at shaping, cleaning, and disinfecting the root canal, being performed by removing all pulp tissue or necrotic remains and microorganisms present in the root canal system. Among the substances proposed as a delay dressing in the endodontic treatment of teeth with chronic periapical reaction, calcium hydroxide stands out. Objective: It was to demonstrate, through a comprehensive review, the main properties of calcium hydroxide, as well as its antibacterial action mechanisms. Methods: After literary search criteria, the selected studies were explored for the construction of the present study, following the PRISMA review rules. The review protocol was based on literary search criteria in major databases such as PubMed, Medline, Bireme, EBSCO, Scielo, and Web of Science. Results and Conclusion: A total of 65 articles were found. Initially, duplication of articles was excluded, resulting in 35 articles. A total of 20 articles were evaluated and 12 were included and developed in this review study. Calcium hydroxide is the most commonly used medication to fight disease-causing bacteria, but when used alone, it may not be able to eliminate these microorganisms. The association of other medications incorporated into calcium hydroxide contributes to positive results with the elimination of more resistant bacteria. Intracanal medications based on calcium hydroxide allow a positive effect on microbial reduction, decreasing the levels of pro-inflammatory cytokines and metalloproteinases.

Pulpal and periapical tissue response after direct pulp capping with endosequence root repair material and low-level laser application

BackgroundThe study aims to investigate the pulp and periapical reaction and healing after capping with EndoSequence Root Repair Material (ERRM) combined with low-level laser application.MethodsIn 6 rabbits, pulps were exposed via class V, half of the samples received a low-level diode laser at 980 nm. Thereafter, cavities were capped with regular-set ERRM. The specimens were processed for histomorphological examination after 2 weeks and two months.ResultsAfter 2 weeks, images show mild inflammation and organized odontoblasts in lased group. The non-lased group shows more severe inflammation. The predentin thickness was thicker in the lased group with statistical significance (p < 0.05). After 2 months, inflammatory cells were sparse in both lased and non-lased groups. In the periapical area, group one showed dilated blood vessels and thick fibrous connective tissues. In group two, there were more numerous maturations of PDL fibers with scattered inflammatory cells and congested blood vessel.ConclusionsUsing low-level laser therapy in combination with ERRM for pulp capping shortens the inflammatory phase and enhances healing.

DISSEMINATION OF Buccomaxillofacial INFECTIONS

The maxillofacial complex shows fascial spaces and cavities that favor the spread of infections that may evolve to death. This case report is from a 6-year-old child who suffered dissemination of abscess from tooth 65 to orbit. He was referred for evaluation by the ophthalmologist with suspected rhabdomyosarcoma, after the buccomaxillofacial exam, presenting fever for 5 days. Clinical and tomographic examination revealed periorbital edema, projection of the eye, eversion of the lower eyelid, with floating consistency, caries with pulp exposition, and periapical reaction, presence of empyema in the maxillary sinus, spreading to ethmoidal air cells, orbit and lower eyelid. The patient was submitted to extraction of the deciduous tooth, opening of the maxillary sinus for drainage and curettage of the exudatory content and drained the lower eyelid. Oxacillin, gentamicin, metronidazole, analgesics, and NSAIDs were used for 10 days. After 15 days, the child returned without clinical changes or sequelae.

Protein Activation in Periapical Reaction to Iodoform Containing Root Canal Sealer.

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. 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. 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. 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.

DENTAL LESIONS IN THE LOWLAND TAPIR (TAPIRUS TERRESTRIS).

Dental ailments, mandibular swelling, and dentoalveolar abscesses are common in tapirs, but knowledge about prevalence or etiology of these lesions in the Tapiridae family in general, and in lowland tapirs (Tapirus terrestris) in particular, is scarce. A recent study identified resorptive lesions of unknown etiology as a common problem in the Malayan tapir (Tapirus indicus). In order to investigate the type and prevalence of dental lesions occurring in lowland tapirs, and to compare these with findings with the Malayan tapir, skulls and teeth from 46 deceased lowland tapirs were visually and radiographically examined. The specimens were divided into subpopulations according to age (juveniles, young adults, adults) and origin (free-range or captive). Dental lesions were identified in 24% (11/46) of the study population. The most common pathologic findings were complicated dental fractures with associated periapical reaction (15%) and periapical reactions of various degrees without associated detectable dental pathology (13%). All these lesions likely originated from dental trauma. As in Malayan tapirs, juveniles had significantly fewer lesions than adults. This study shows that dental lesions present frequent problems for lowland tapirs, occurring both in captive and in free-ranging individuals, and indicates that increasing age should be considered a risk factor for the development of these lesions. Notably, the predominant dental problems in lowland tapirs and Malayan tapirs are not the same.

Pulpal and Periapical Response After Restoration of Deep Cavities in Dogs' Teeth With Filtek Silorane and Filtek Supreme XT Systems

This study evaluated, histopathologically, the pulpal and periapical response to a silorane-based resin (Filtek Silorane) and a methacrylate-based nanoparticle resin (Filtek Supreme XT) in deep cavities in dogs, having zinc oxide and eugenol-based cement (ZOE) as a control. The tooth/bone blocks were collected after 10 and 90 days and processed for microscopic analysis of the dentin, pulp, and periapical tissues using a score system. Data were analyzed statistically by Kruskal-Wallis and Dunn post-test (α=0.05). At 10 days, the pulp, connective tissue, and periodontal ligament showed normal characteristics. No resorption areas were observed. Both resins caused significantly less (p<0.05) periapical and pulpal inflammatory response than ZOE. At 90 days, for all materials, the connective pulp tissue was healthy and dense, with a normal blood vessel system. The apical and periapical region had normal structure and thickness. The use of the Filtek Silorane and the Filtek Supreme XT resins caused no adverse pulpal and periapical reactions after restoration of deep dentin cavities in vivo.

Versorgung von Zahnfrakturen beim Kurzkrallenotter Aonyx cinerea (Illiger, 1815) – ein Beitrag zur Zahnhygiene bei Marderartigen (Mustelidae) in menschlicher Obhut

The oral examination of a five and half years old Asian Small-Clawed Otter (Aonyx cinerea) showed the accumulation of tartar and two complicated tooth fractures. The tartar has been removed with an ultrasonic device. The fractured molar of the mandibula has been extracted and the damaged canine tooth of the maxilla has been treated by an endodontic procedure. Half a year later the x-ray control of the canine tooth indicated a stop of the periapical reactions.

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-1β 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.

Histopathological evaluation of different methods of experimental induction of periapical periodontitis

This study evaluated histopathologically different methods of experimental induction of periapical periodontitis. The radiographic and microbiological evaluations have been performed in a previous investigation. Fifty-seven root canals from dogs' teeth were assigned to 4 groups. In GI (n=14) and GII (n=14), the root canals were exposed to oral environment for 180 days; in GIII (n=14) and GIV (n=15) the root canals were exposed for 7 days and then the access cavities were restored and remained sealed for 53 days. The root apices of GI and GIII were perforated, whilst those of GII and GIV remained intact. After induction of periapical periodontitis, the dogs were euthanized. Serial sections were obtained and stained with hematoxylin and eosin. Data of the histopathological evaluation were submitted to Kruskal-Wallis and Dunn's tests at 5% significance level. The inflammatory periapical reaction and resorption of mineralized tissues were less intense in GII than in the other groups (p<0.05). There was no histopathological difference among the experimentally induced periapical lesions in the teeth with coronal sealing. On the other hand, when coronal sealing was not performed, greater intensity of induced periapical periodontitis was observed in the teeth with apical perforation.

Pulpal and periapical reaction to formocresol and depulpin® in the rat teeth

One fifth dilution of formocresol is usually used for pulpotomy of the primary teeth and emergency pulpotomy of the permanent teeth. However the use of formaldehyde has been subjected to criticism because it may be absorbed into the blood stream and become distributed systemically, it nay also alter the pulp tissue rendering it immunologically active, and have carcinogenic potential. Recently Depulpin(VoCo., Germany) gains popularity as a devitalizing agent during root canal therapy in spite of high concentration of 49 % paraformaldehyde because it facilitate devitalization of pulp and make root canal therapy easier But there have been not enough publications about the reaction of pulp and periapical tissue caused by Depulpin. This study was performed to evaluate the histological changes in pulp and periapical tissue of rats after pulpotomy using formocresol and Depulpin and to elucidate the toxic effects of these agents. Thirty six Sprague-Dawley rats were anesthetized by intraperitoneal injection of ketamine Maxillary first molar teeth were used for pulpotomy with formocresol and Depulpin. Rats were sacrificed after 2 days, 4 days, 1 week, 2 weeks, 3 weeks and 4 weeks respectively. Specimens were histologically observed by light microscope changes in pulp and periapical tissue. The obtained results were as follows. 1. Formocresol group A zone of fixed tissue. in which odontoblasts could clearly be defined, was present directly underneath the pulpotomy dressing in almost all teeth of this group. This was followed by an area of necrotic tissue which resembled dried out fibrous tissue with no cellular detail except some pyknotic nuclei. In the specimens of after 2 days, 4 days, 1 week, 2 weeks in which vital tissue was present, it was separated from the fibrous area by a zone of inflammation. In the specimens of after 3 weeks and after 4 weeks, inflammatory infiltrate was in the periodontal ligament adjacent to the apical foramina of the teeth. 2. Depulpin group The area of necrotic tissue which had no cells and fibers, was present adjacent to the dressing. This was followed by dried out fibrous tissue with no cellular details except some pyknotic nuclei, A short stump of vital pulp with odontoblasts was present at the end of the canal after 2 days. Inflammatory infiltrate was in the periodontal ligament after 4 days and after 1week. Severe root resolution and necrosis of periapical tissue opposite the root resorption site were defined after 2 weeks and after 3 weeks. Periapical lesion which consist of necrotic tissue surrounded by a fibrous connective wall, was found after 4 weeks. The results indicated that Depulpin can cause more adverse reaction to the dental pulp and periapical tissue than formocresol, and further studies are needed for its clinical use with safety.

In vivo antimicrobial activity of 2% chlorhexidine used as a root canal irrigating solution

The aim of the present study was to evaluate the in vivo antimicrobial activity of 2% chlorhexidine gluconate (FCFRP-USP) used as a root canal irrigating solution in teeth with pulp necrosis and radiographically visible chronic periapical reactions. Culture techniques and measurement of the inhibition zone were used. Twenty-two root canals of incisors and molars of 12 patients were used. After accessing the canal, the first root canal sample was collected with two sterile paper points that were transferred to a tube containing reduced transport fluid. The root canal was instrumented using chlorhexidine solution. A small sterile cotton pellet was placed at the root canal entrance, and the cavity was sealed with zinc oxide-eugenol cement. The canals were maintained empty for 48 h. Three sterile paper points were then introduced to absorb the root canal fluid (second sample). One paper point was placed on an agar plate inoculated with Micrococcus luteus ATCC 9341 and incubated for 24 h at 37 degrees C, and the other two were submitted to microbiological evaluation. Present in 10 cases at baseline, mutans streptococci was reduced by 100% at the second assessment. Treatment showed an efficiency of 77.78% for anaerobic microorganisms at the second assessment. These data suggest that chlorhexidine prevents microbial activity in vivo with residual effects in the root canal system up to 48 h.

Coronal leakage: Endotoxin penetration from mixed bacterial communities through obturated, post-prepared root canals

Coronal leakage has been considered as one of the major causes of failure in root canal treatment. Bacteria have been shown to penetrate the root canal obturating materials and influence the periapical tissues. Endotoxin, a component of Gram-negative bacteria, is a potent inflammatory agent and may be able to penetrate obturating materials faster than bacteria. This in vitro study examined the possible penetration of post-prepared canals by endotoxin and bacterial cells derived from mixed bacterial communities. Results showed that both bacteria and endotoxin were able to penetrate the obturating materials in post-prepared canals; however, endotoxin penetration was faster than bacterial. If one speculates that a similar sequence of events occurs clinically, then such a rapid penetration of endotoxin could lead to an early periapical reaction, with subsequent treatment failure and need for retreatment or periapical surgery. The need for an immediate and proper coronal restoration after root canal treatment is therefore reinforced.

Usage test of four endodontic sealers in Macaca fascicularis monkeys

Root canals with vital pulps in four Macaca fascicularis monkeys were subjected to pulp extirpation and root filling with gutta-percha and sealer, either AH26, Endomethasone, Kloroperka N-NONETH, or ProcoSol. Observation periods were 1 and 6 months. The results of treatment were evaluated by radiographic analysis (periapical index scores) and by histopathologic assessment of the remaining pulp and periapical tissues. Sixty roots with acceptable termination (between 0.5 and 3 mm from apex) of the root fillings and adequate histopathologic specimens were available for analysis. These roots were equally distributed in each observation period group and among the four material groups. Radiography indicated periapical pathosis in 6 of the 60 roots—4 at 1 month and 2 at 6 months. Periapical inflammation was observed on histopathologic examination in 17 roots—11 after 1 month and 6 after 6 months. Histologic and radiographic assessment of periapical inflammation was significantly correlated ( p < 0.01, χ 2) at the 6-month observation period. No granuloma or cyst formation was evident on histologic examination. The magnitude of the inflammatory response appeared unrelated to the endodontic sealer used, and several inflammatory foci were not related to foreign bodies in the tissues. Bacteriologic sampling showed growth in thioglycollate broth cultures in 9 of the 60 roots, but the presence of cultivable bacteria by this technique was unrelated to inflammatory changes. Histologic demonstration of bacteria was positive in 4 roots, all of which were associated with inflammatory periapical reactions. The method applied in the present study did not provide a sensitive discrimination among endodontic materials of widely different chemical composition.

Tissue reaction to endodontic materials: Methods, criteria, assessment, and observations

The purpose of this study was to develop methods and criteria for the testing of the biocompatibility of endodontic materials. One hundred twenty-one teeth from 12 baboons (Papio anubis) were used to test three sealers: AH26, Kerr pulp canal sealer, and Kloroperka N.Ø. Gutta-percha cones were used as solid core in all cases. Under disinfected conditions, access preparation was performed, and with working length approximately 1.0 mm short of the foramen, the instrumentation of the root canal was started, using sodium hypochlorite (1%) for irrigation. After the root canals were cleaned and shaped, they were obturated with gutta-percha cones and the sealer, and by lateral condensation technique. Histologic periapical reactions were evaluated at 1, 7, 30, 365, 730, and 1095 days. The methods and criteria used were adequate for ranking of the biocompatibility of the tested materials in the short and long periods. At short observation periods (1 to 7 days) AH26 caused severe reactions, and Kerr pulp canal sealer and Kloroperka N.Ø., moderate and mild reactions, respectively. At 2- and 3-year observation periods the ranking was AH26, mild; Kerr pulp canal sealer, moderate; and Kloropercha N.Ø., severe.

Periapical reactions to calcium hydroxide‐containing sealers and AH 26® in monkeys

The long-term effect on periapical healing (8-14 months) of CRCS and Sealapex was compared with that of AH 26. Vital pulpectomy and root canal filling by the hybrid thermomechanical method were performed in teeth of 3 young monkeys. Ten roots with CRCS, 10 with Sealapex and 7 roots with AH 26 were examined after demineralization and routine histological processing. Hematoxylin and eosin and Brown & Brenn staining for micro-organisms were employed. Mild to severe inflammatory lesions were found at the apical foramina of the roots filled with AH 26 and CRCS. Most of the Sealapex specimens showed no inflammatory cells, except macrophages with sealer particles. A striking finding was a tendency towards apical obliteration with calcified tissue in roots filled with Sealapex, apparently following resorption of the sealer. Such a tendency was seldom observed with the other sealers. However, both AH 26 and Sealapex were irritating for a long time when pushed into bone. Despite the interesting results with Sealapex, additional research is needed before its use can be unconditionally recommended. This sealer has not yet been tested in infected cases and its ability to be resorbed, which is an advantage when it precedes replacement by calcified tissue, may become a disadvantage if it is not followed by apical obliteration.

Pulpal and periapical reactions to glutaraldehyde and paraformaldehyde pulpotomy dressing in monkeys

Pulpotomies were performed in 23 young posterior teeth of two vervet monkeys. Two dressings were compared: glutaraldehyde in ZOE paste and paraformaldehyde in the same vehicle and ZOE alone served as control. The teeth and their surrounding structures were examined histologically after 3 and 9 months. Paraformaldehyde induced total pulpal necrosis and chronic apical inflammation. In all glutaraldehyde-treated teeth, the pulp remained mostly vital and there was no periapical reaction. Calcifications in the pulp cavity were evident. The vehicle alone, ZOE, also permitted the pulp to remain vital, exhibiting calcifications but no full bridges. None of the experimental specimens showed complete pulpal healing; however, in contrast to paraformaldehyde-treated teeth, glutaraldehyde-treated ones retained their vitality and produced no apical involvement.

Influence of combinations of oral bacteria on periapical tissues of monkeys.

The present study deals with the ability of 11 bacterial strains, in various combinations, to induce periapical reactions. The indigenous oral bacteria were originally isolated from an experimental apical periodontitis in monkey. Eight of the strains were complete collection isolated from one root canal. These strains were inoculated together, in equal proportions, into 12 root canals. In addition, 63 canals were inoculated with other combination or separate strains. At the end of the experimental period it was found that in the mixed infections the Bacteroides oralis strain predominated in most root canals. In contrast, this Bacteroides strain was not reisolated in any of nine root canals when inoculated in a pure culture. Enterococci, however, survived as pure cultures in all canals. The mixed infections showed the greatest capacity of inducing apical periodontitis, as revealed by radiography, and most pronounced was the "eight-strain collection". The facultatively anaerobic streptococci induced only weak periapical reactions.