Nonsurgical management of periapical lesions: a prospective study

A total of 93 cases comprising 132 teeth with signs and symptoms or radiographic evidence of periapical pathoses were treated endodontically and were followed up for a period of 2 years. Nonsurgical management was successful in 84.4% of the cases. Histopathologic examination of tissue specimens from cases in which treatment failed revealed that only 35.7% of the cases involved apical cysts, while the remaining 64.3% involved chronic inflammatory tissue. Interestingly, 50% of the failures were observed at or 1 year after completion of treatment, which stresses the need for long-term follow-up of treated endodontic cases. In this study, a successful outcome did not seem to be dependent on either the nature or the size of the lesion, even though it is true that treatment of larger lesions failed more frequently. There seems to be some individual immunologic response variation, which may influence the final outcome of the treatment. Gyromatic instruments were used in 44 of the 93 cases treated and were evaluated and compared with hand instruments in clinical situations. Gyromatic instruments were found to be more convenient and safer to use, since their use improved visibility and eliminated the risk of the instruments' falling into the throat and being aspirated. They exhibited good flexibility and could easily negotiate curved canals without breaking. Used judiciously, these would be efficient tools in the endodontist's armamentarium.     

Implants placed into alveoli with periapical lesions: an experimental study in dogs

Oral and Maxillofacial Surgery - To histologically analyze the effect of a curettage of the granulation tissue on healing at implants installed immediately after the extraction of teeth presenting...     

Nonendodontic periapical lesions: a retrospective study in Chile

AIM: To determine the frequency with which the histopathological diagnosis of periapical lesions contributes to a change in the clinical diagnosis. METHODOLOGY: Cases having a clinical diagnosis of disease resulting from dental pulp necrosis were selected from the database of the Oral Pathology Reference Institute between 1975 and 2005. Cases with different histopathological diagnoses were determined and information about age and gender of the patient, location of associated tooth, pulp status and the histopathological diagnosis were recorded. The percentage of nonendodontic periapical lesions was then determined. RESULTS: In the 30-year period, 32,423 [corrected] biopsy specimens were received. Overall 4006 (9.13%) had a clinical diagnosis of pulpal necrosis with associated pathosis in the periradicular area. Within this group, 26 cases (0.65%) had a histopathological diagnosis of nonendodontic pathology. Keratocystic odontogenic tumour was the most frequent nonendodontic lesion (11 cases) in the periradicular region followed by central giant cell granuloma (three cases), chronic sinusitis (three cases) and one case each of the following lesions: nasopalatine duct cyst, lateral periodontal cyst, calcifying cystic odontogenic tumour, ameloblastic fibroma, squamous odontogenic tumour, cemental dysplasia, haemangioma, foreign body cell granuloma and amalgam tattoo. CONCLUSIONS: The histopathological study of periapical pathosis can occasionally reveal nonendodontic lesions. Odontogenic tumours made up the largest group.     

Endotoxin and gram-negative bacteria in the rat periapical lesions.

The purpose of this study was to measure the amount of endotoxin as well as to identify Gram-negative bacteria in experimental periapical lesions in rats. Molar pulps were exposed and infected and the amount of endotoxin in the periapical tissue of the right mandibular first molar was measured by Endospecy, while the colony number of Gram-negative bacteria was determined in the same region of the left mandibular first molar. In the control animals, the amount of endotoxin in the periapical tissues did not change at all during the experimental period, and no Gram-negative bacteria were isolated. In the experimental animals, the amount of endotoxin in the periapical tissues increased gradually from 1 to 70 days, and its level was significantly greater than that of control animals after 7 days. Gram-negative bacteria were isolated from the periapical tissues and their number gradually increased from 1 to 14 days (26 to 82%), but decreased at 21 days. It was approximately 60% from 28 to 70 days. The results of this study showed that the amount of endotoxin in the periapical tissues gradually increased with increasing time and that Gram-negative bacteria were isolated from the same region but did not increase in number concurrently with the increase in the amount of endotoxin.     

Collagenase-3 (MMP-13) is expressed in periapical lesions: an immunohistochemical study

AIM: To determine whether or not matrix metalloproteinase 13 (MMP-13) is present in periapical granulomas with and without epithelium. METHODOLOGY: Seventeen open periapical granulomas of pulpal origin (seven lesions without epithelium and 10 with proliferating epithelium) were fixed in formalin and then embedded in paraffin prior to being processed for immunohistochemical analysis. A monoclonal antibody against human MMP-13 was used to evaluate MMP-13 expression. Immunocomplexes were subsequently treated with the secondary antibody and then detected by means of streptavidin peroxidase. Immunoreactivity was visualized by development with 3,3'-diaminobenzidine. RESULTS: An immunopositive cytoplasmatic reaction for MMP-13 was observed in all the specimens, although the immunostaining by anti-MMP-13 antibody was heterogeneous and its levels varied according to histopathological findings. In periapical lesions without epithelium MMP-13 immunolabelling was detected in a few fibroblast-like cells, and in some plasma cells within the granulomatous tissue. A clear upregulation of MMP-13 expression was detected in periapical lesions with epithelium, especially in small island and thin strands of epithelium. CONCLUSIONS: The expression pattern of MMP-13 demonstrates that it is involved in the conversion of a periapical granuloma with epithelium into a radicular cyst. This property is related to the ability of MMP-13 to influence not only the migration of epithelial cell but also the invasion of granulomatous tissue.     

Histopathological profile of surgically removed persistent periapical radiolucent lesions of endodontic origin

Aim  To determine the types of periapical lesions associated with root filled teeth with persistent periapical pathosis that required surgical treatment based on specific inclusion and exclusion criteria.
Methodology  Periapical lesions from a consecutive clinical sample of 100 patients were examined histopathologically to determine a definitive diagnosis.
Results  Females were more represented ( n  = 56), the average age was 46.5 years and there were no age differences between gender or lesion type. A diagnosis of periapical granuloma was the most common finding with a similar number present in females ( n  = 40) and males ( n  = 37). A cyst was present in 18% of the cases with a majority of females ( n  = 12) represented in the sample. Evidence of foreign material, with an appearance consistent with endodontic sealer materials, was seen in 25 periapical granulomas, two cysts and one scar. Two periapical scars were seen, one had a history of apicectomy and amalgam root-end filling while the other was associated with extruded root filling material.
Conclusions  By using defined clinical inclusion and exclusion criteria a predictable clinical diagnosis of a persistent periapical lesion due to endodontic origin can be reliably made. Periapical granulomas and cysts were the most common periapical lesions of endodontic origin associated with persistent periapical pathosis with the overall incidence of periapical cysts similar to previous studies. The presence of endodontic material in a high proportion of periapical lesions suggests a cause-effect association with the inference that clinicians should employ canal preparation techniques that limit apical extrusion of material.     

根尖周炎厌氧菌培养结果分析

对４６例根尖周炎患者牙根管内厌氧菌分离培养，结果分离出厌氧菌共１３９株，其中急性根尖周炎９５株，慢性根尖周炎４４株，厌氧菌分离率为９６％，检出率较高的厌氧为梭杆菌属、消化链球菌属、丙酸杆菌属、拟杆菌属、卟啉菌属、普里沃菌属     

Macrophages in periapical lesions

Macrophages are major constituents of periapical granulomas. They have a central protective role in both innate immunity and adoptive, antigen-specific immune response. Macrophage activation may occur in periapical granulomas by cytokines produced by antigen-activated T-lymphocytes; by bacterial endotoxin, as part of the innate immunity; or by both these processes. Recent studies in athymic animals have shown that periapical granulomas may develop independently of T-lymphocytes. This observation reveals the major role that the activated macrophage may have in the formation of periapical lesions. Only a few of the macrophages in the periapical granuloma are activated. Current studies indicate that these activated cells are the source of the bone-resorbing cytokines in the periapical granuloma. Understanding the central role of the activated macrophage in the formation as well as the perpetuation of periapical lesions may lead to the development of new diagnostic and therapeutic tools in endodontics.     

Macrophages in periapical lesions

Abstract – Macrophages are major constituents of periapical granulomas. They have a central protective role in both innate immunity and adoptive, antigen‐specific immune response. Macrophage activation may occur in periapical granulomas by cytokines produced by antigen‐activated T‐lymphocytes; by bacterial endotoxin, as part of the innate immunity; or by both these processes. Recent studies in athymic animals have shown that periapical granulomas may develop independently of T‐lymphocytes. This observation reveals the major role that the activated macrophage may have in the formation of periapical lesions. Only a few of the macrophages in the periapical granuloma are activated. Current studies indicate that these activated cells are the source of the bone‐resorbing cytokines in the periapical granuloma. Understanding the central role of the activated macrophage in the formation as well as the perpetuation of periapical lesions may lead to the development of new diagnostic and therapeutic tools in endodontics.     

Radiographic evaluation of periapical healing after obturation of infected root canals: an in vivo study

AIM: To radiographically compare periapical repair of roots with infected root canals obturated in one-step or with calcium hydroxide (Ca(OH)2) intracanal medication in two steps. METHODOLOGY: Standardized preoperative periapical radiographs were taken of 72 roots of vital dogs' teeth. All roots were then aseptically instrumented to ISO size 45. As negative controls, 12 roots were aseptically obturated. The remaining roots were infected with dental plaque and closed. Six weeks later, apical periodontitis was radiographically confirmed in the infected roots. The roots were divided into the following groups: group 1, one-step (n = 24); roots were irrigated with 10 cc saline, obturated, and permanently restored. Group 2, Ca(OH)2 (n = 24); roots were treated as in group 1, except that after saline irrigation Ca(OH)2 medicament was placed in the canal 1 week before obturation. Group 3, positive control (n = 12); the roots were irrigated with saline, access permanently closed but canals not obturated. Group 4, negative control (n = 12); previously aseptically obturated roots were permanently restored. After 6 months, standardized postoperative radiographs were obtained. Three independent evaluators blinded to the treatment groups evaluated the preoperative and postoperative radiographs. The evaluators were instructed to rate each root, based on changes on the radiographs, as failed, improved or healed. RESULTS: Radiographically, the percentage of cases that completely healed were similar for the one-step and Ca(OH)2 groups (35.3% vs. 36.8%). However, the Ca(OH)2 group had fewer failed cases (15.8% vs. 41.2%) and more improved cases (47.4% vs. 23.5%) than the one-step group. CONCLUSION: Power statistics demonstrated that at 43 cases per group, Ca(OH)2 treatment would be statistically superior to one-step treatment. We consider this number to be clinically important.     

An immunohistological study of the localization of bacteria invading root pulpal walls of teeth with periapical lesions

We immunohistologically examined the prevalence and localization of bacteria invading dentinal tubules of the roots of teeth with infected canals. Forty extracted teeth with apical lesions were selected and divided into two groups: a group of untreated teeth and a group of canal-enlarged teeth. The bacteria in the specimens were detected by Brown-Brenn stain and the labeled-streptavidin-biotin method with specific antisera for 16-bacteria. Seventy percent of the examined teeth showed bacteria invading the dentinal tubules of the roots. Fusobacterium nucleatum, Eubacterium alactolyticum, E. nodatum, Lactobacillus casei, and Peptostreptococcus micros were abundant. Even in the canal-enlarged group, invasion of bacteria was observed in 65% of teeth. This study revealed the actual condition of bacteria in infected root dentin and suggested that the canal-enlargement procedure could not completely remove all the bacteria in the infected dentinal tubules of the root.     

Histological evaluation of the presence of bacteria in induced periapical lesions in monkeys.

In endodontic periapical lesions, both presence and location of bacteria are controversial. Various experimental techniques have produced differing results perhaps related to potential artifacts such as contamination during specimen recovery. Our objective was to examine for bacteria in uncontaminated, undisturbed periapical lesions in an animal model. Pulp necrosis was induced by exposing molars in nonhuman primates and closing the exposure after 1 week with amalgam. Lesions developed at 18 apices. After 7 months, block sections including tooth and surrounding tissues were removed, processed histologically, and Gram stained. Bacteria, primarily Gram positive, were consistently identified in necrotic tissue in canals. Two canals demonstrated bacterial masses to the apical foramen. No bacterial colonies, only intracellular microorganisms, were seen periapically. Inflammatory lesions seemed to resist the spread of bacteria, confining them to the canal space. Bacterial masses at the apical foramen could contaminate periapical tissues during surgery or extraction and give a false positive upon microbiological sampling.     

Microorganisms in closed periapical lesions

The purpose of this study was to investigate the microorganisms of strictly selected closed periapical lesions associated with both refractory endodontic therapy and pulpal calcification. Definitive criteria were established that assured complete clinical isolation of the periapical lesion from the oral and periodontal environment. A total of 13 criteria-referenced lesions were selected from 70 patients with endodontic surgical indications. A well controlled culturing method was used in all cases and samples were taken by one clinician at three separate sites during each surgery. Samples taken at the surgical window and within the body of the lesion served as controls, whilst a third sample was taken at the apex. In all 13 cases, samples taken from the apex yielded microorganisms comprising 63.6% obligate anaerobes and 36.4% facultative anaerobes. Prevalence of the isolated species was 31.8% for Actinomyces sp., 22.7%, Propionibacterium sp., 18.2% Streptococcus sp., 13.6% Staphlyococcus sp., 4.6% Porphyromonas gingivalis , 4.6% Peptostreptococcus micros and 4.6% Gram-negative enterics. The results of this investigation indicate that closed periapical lesions associated with calcified teeth or those resistant to root canal treatment harbour bacteria. The inability to eradicate all root canal microorganisms during root canal treatment, along with anatomical factors, may allow further bacterial colonization of the root apex and surrounding periapical tissues, and consequently prevent healing.