SEARCH · PubMed Health

Results for “Periapical Tissue”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources

PubMed1999

Cholesterol as an aetiological agent in endodontic failures--a review.

Presence of cholesterol clefts in apical periodontitis lesions is a common histopathological observation. However, a potential aetiological association of cholesterol crystals to non-resolving apical periodontitis lesions after endodontic treatment has been suggested only recently. This article is an attempt to explain the biological basis for the inability of body cells to eliminate the local accumulation of cholesterol crystals, and to consolidate available clinical and experimental data in support of the view that massive accumulation of cholesterol crystals in inflamed periapical tissues can interfere with the periapical healing after conventional root canal treatment. As the irritating cholesterol crystals and certain other aetiological agents of failed endodontic treatment exist outside the root canal system, it is concluded that re-treatment alone, of such cases, is unlikely to resolve the factors that sustain the lesion. Apical surgery is indicated for successful management of such cases.

Animals↗

PubMed1978

Immunopathogenesis of chronic periapical lesions. A review.

The pathogenesis of periapical lesions has not been fully elucidated. Currently, the possibility of its being an immunologic phenomenon is receiving much attention. This article presents a review of the literature concerning immunologic reactions which may involve periapical lesions. It appears that antigen-antibody complexes and IgE-mediated reactions can initiate preliminary changes in periapical tissues. It is also likely that delayed hypersensitivity participates in the perpetuation and progression of periapical disease.

Antibodies↗

PubMed1997

Barrier membrane techniques in endodontic microsurgery.

The ultimate goal in endodontic microsurgery is the predictable regeneration of periapical tissues. One of the main concerns in treating an endodontically treated tooth which has a through-and-through osseous defect is that incomplete bone healing may be inevitable. This article reviews the use of different barrier membranes for bone regeneration. In addition, the indications, techniques, and prognosis of calcium sulfate in guided bone regeneration are presented.

Alveolectomy↗

PubMed1990

Changes in CGRP-immunoreactive nerve fibres during experimental tooth movement in rats.

Immunohistochemical localization of calcitonin gene-related peptide (CGRP) was used to investigate changes in nerves expressing CGRP in periodontium and pulp during experimental mesial movement of the first maxillary molar in rats. The orthodontic appliance consisted of a coil spring connecting the first maxillary molar on one side to the central incisors. After 5 days with a continuous force of 30-50 g the animals were perfused after an overdose of anaesthetic. Serial sections from the experimental and control jaws were exposed to the avidin-biotin-peroxidase technique for demonstration of CGRP-immunoreactive (IR) nerve fibres. The induced tooth movement caused reproducible changes in the relative number of CGRP-IR nerves as well as morphological alterations within parts of the nerve supply of the experimental teeth and related tissue structures. The majority of the experimental teeth showed increased number of CGRP-IR nerves in the coronal pulp and periapical tissues. The results indicate that peptidergic nerve fibres immunoreactive for CGRP takes an active part in tissue responses in pulp and supporting tissues during experimental tooth movement.

Animals↗

PubMed1994

Morphologic study of tissue changes occurring in the apical third and periapex of rat molars after endodontic treatment performed under different occlusal conditions.

The purpose of the present study was to carry out a histologic study of the periapical changes of the maxillary first molar of rats submitted to endodontic treatment under different occlusal conditions. The experiment was carried out under conditions analogous to those used in clinical practice. Pulpotomy, pulpectomy and chemomechanical preparation of the mesial root canal were carried out according to previously established techniques and the mesial root canal was filled with cement and gutta-percha. A glass ionomer cement was used as restorative material under conditions of subocclusion, normal occlusion and excessive occlusal forces. No inflammatory reaction of periapical tissue was observed under the three conditions used, and active closing of the root canal was observed 15 days after the procedure, with the formation of cementum replacing the pulpar remnant.

Animals↗

PubMed1985

Healing and revascularization of apical periodontium and dental pulps in apicoectomized and nonapicoectomized tooth replants in monkeys. A study of fully developed teeth.

This report primarily concerns an experimental study of the effect of apicoectomy on the healing and revascularization of the periodontal membrane and dental pulps in tooth replants. Five rhesus monkeys (Macaca mulatta) were subjected to surgical procedures in which twenty incisor teeth were extracted and immediately replanted. Ten of these incisors were subjected to apicoectomy. Healing and revascularization of periapical tissues and dental pulps were evaluated by histologic and India-ink-perfusion techniques. Apicoectomized replants were characterized by (1) loss of dental substance (tooth apex) and creation of large periapical spaces, (2) exposure of dental pulps and production of periapical inflammatory processes with destruction of alveolar bone, and (3) blocking of normal healing because of persistence of chronic periapical inflammatory processes. In contrast, nonapicoectomized replants depicted short-lived primary inflammatory responses and healing processes characterized by variable histologic responses.

Animals↗

PubMed1997

An experimental study of the removal of cemented dowel-retained cast cores by ultrasonic vibration.

A technique for the removal of cemented post-cores by means of ultrasonic vibration was studied clinically and histologically. The removal time was measured for 80 extracted human teeth, including 40 single-rooted teeth and 40 multiple rooted ones and then statistically analyzed. The periapical tissue reaction to the ultrasonic vibration was also examined histologically in dogs. The best result was achieved when lateral vibration was simultaneously given by 2 removal tips using 2 ultrasonic generators. There was little harmful influence on the periodontal tissue, excluding a transient reversible reaction.

Animals↗

PubMed2001

Cytotoxicity of halothane on human gingival fibroblast cultures in vitro.

Recently halothane has been reported to be the most suitable alternative to chloroform in dissolving gutta-percha. Periapical tissue toxicity of halothane is not completely known. In this study gutta-percha dissolved by halothane was evaluated with the almar blue dye assay using human gingival fibroblast cultures. The cytotoxic effects of halothane on human gingival fibroblasts depended on the exposure dose, frequency, and duration. A reduced concentration and smaller amount of gutta-percha solvents may minimize the cytotoxic effects on host tissues.

Cell Adhesion↗

PubMed2002

The periapical space--a dynamic interface.

The ultimate aim of endodontic treatment is to encourage the healing of apical periodontitis, or to prevent it from occurring if it was not present prior to treatment. Apical periodontitis is a general term used to describe an inflammatory response to irritation caused by the contents of a root canal system and it has several distinct forms. The most common is a granuloma but this can develop into other disease entities such as an abscess, a periapical pocket cyst or a true cyst, all of which present as radiolucencies. However, periapical radiolucencies may also be caused by extra-radicular infections, foreign body reactions and periapical scars, or they may be due to other tumours and cysts that have not originated from pulp disease. Practitioners must recognise and understand the different pathological entities and the dynamic interactions that occur in the periapical tissues in order to correctly diagnose and treat these conditions.

Chronic Disease↗

PubMedDate not supplied

Traumatically injured primary incisors: a clinical and histological study.

World-wide epidemiological studies state that from 8 percent to 30 percent of children up to 7 years of age sustain injury to primary incisors, including crown fracture, root fracture, tooth avulsion, and dental displacement, which result in malformation of permanent incisors depending upon their state of development. In this study, traumatized primary incisors were evaluated clinically and radiographically, with the following data recorded: exact or approximate time-interval of traumatic episode(s) and extraction, mobility, color change, sensitivity to percussion/palpation, swelling, sinus tract, caries, crown/root fracture, periodontal/periapical lesions, external/internal root resorption, mineralization, and obturation. Based upon the local damage and developmental age, 138 teeth were extracted, fixed in 10 percent formalin, and processed for histological evaluation according to routine methodology. Histologic findings were: the presence of varying extent of necrosis, bacteria in the area of necrosis--not in all cases--neutrophilic leukocytes, chronic inflammatory cells, pulpal calcifications, resorption/apposition, and circulatory changes. The blood pigment distinguished hemorrhage due to extraction from pathologic circulatory changes. All the described reactions varied in intensity and extent with the time interval and the assumed force of the original trauma. Physical trauma to primary teeth caused pulpal damage, which could involve periapical tissue, depending on the extent of the initial damage.

Child↗

PubMed2000

The periapical space--a dynamic interface.

The ultimate aim of endodontic treatment is to encourage the healing of apical periodontitis, or to prevent it from occurring if it was not present prior to treatment. Apical periodontitis is a general term used to describe an inflammatory response to irritation caused by the contents of a root canal system and it has several distinct forms. The most common is a granuloma but this can develop into other disease entities such as an abscess, a periapical pocket cyst or a true cyst, all of which present as radiolucencies. However, periapical radiolucencies may also be caused by extra-radicular infections, foreign body reactions and periapical scars, or they may be due to other tumours and cysts that have not originated from pulp disease. Practitioners must recognize and understand the different pathological entities and the dynamic interactions that occur in the periapical tissues in order to correctly diagnose and treat these conditions.

Acute Disease↗

PubMed1996

Induced hypoxia in rat pulp and periapex demonstrated by 3H-misonidazole retention.

Cellular hypoxia may be a useful indication of tissue distress in the dental pulp that could be used to investigate the early stages of pulpal responses. Tritiated misonidazole (3H-MISO) is a marker which preferentially labels cells with decreased oxygen tension (hypoxia). The experiments reported here were carried out to determine whether this agent could distinguish between hypoxic and normoxic pulp and periapical tissues. Rats were injected intra-peritoneally with either 3H-MISO, unlabeled MISO, or saline, then divided into normoxic, hypoxic, and control groups. Normoxic animals were maintained at ambient pressure. We induced hypoxia by maintaining animals in a hypobaric chamber at 0.5 atm for 24 hrs. 3H-MISO retention was assessed by quantitative analysis of tissue autoradiographs. 3H-MISO retention rates in normoxic animals showed little variation except for increased retention in mature ameloblasts and immature odontoblasts in the continually erupting incisor. In both incisor and molar pulps, hypobaric hypoxia significantly increased 3H-MISO retention when compared with normoxic controls. Hypobaric hypoxia also resulted in intense 3H-MISO retention in cellular cementum, periodontal ligament, osteocytes, and, occasionally, in molar pulp horn odontoblasts. This study demonstrated that, with standard autoradiographic techniques, 3H-MISO can label induced hypoxic disturbances in the pulp and surrounding periodontium.

Ameloblasts↗

PubMed1991

[Application of tricalcium phosphate in one visit root canal treatment].

This paper reports the successful use of tricalcium phosphate (TCP) as periapical barrier material in animal experiments and clinics. The results of animal experiments showed that TCP had good biocompatibility with periapical tissues. At 6 weeks there were osteoids deposited on the surface of TCP. At 12 weeks osteogenesis occurred around the TCP particles and combined each other closely. At 24 weeks around the periapex there were bone deposits and a tendency of apical closure. On the basis of experiments TCP was used to treat 17 chronic periapicitis in 15 patients. All cases were young permanent teeth with immature roots. It is suggested that TCP can be applied directly in chronic periapicitis with open apices of young permanent teeth. From 6 to 12 months after filling with TCP the X-rays showed that radiolucencies reduced or eliminated, bone trabecula formed and periapical lamina dura reestablished.

Adolescent↗

PubMedDate not supplied

Effects of formocresol alone vs. formocresol with eugenol on macrophage adhesion to plastic surfaces.

PURPOSE: The purpose of this study was to compare the in-vitro effects of a European-based formocresol formulation that incorporates eugenol with formocresol alone on the adhesion of macrophages to plastic surfaces. METHODS: Macrophages were obtained from Wistar rats. The adherence capacity of macrophages to a plastic surface was determined. Assays were carried out in Eppendorf tubes incubated for 15 min at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index was calculated. RESULTS: Results showed that both formocresol/eugenol and formocresol alone significantly decreased the adherence index of macrophages. The formocresol formulation that incorporated eugenol was more potent in inhibiting macrophage adhesion than formocresol alone. CONCLUSIONS: Taking into account that adherence to a substrate is the first step in the phagocytic process of macrophages and in antigen presentation, both formocresol formulations could inhibit macrophage function and modulate immune and inflammatory responses in dental pulp and periapical tissues.

Analysis of Variance↗

PubMed1995

Pulpal and apical changes secondary to segmental osteotomy in the mandible--an experimental study.

Posterior segmental osteotomies were performed on 7 dogs to investigate postoperative changes in the pulpal and periodontal tissue. Osteotomy cuts were made at various distances from the apices of roots. After 3 to 6 months, results were evaluated clinically, radiographically and histopathologically. Clinical and radiographic healing of the osteotomy sites was uneventful. Histological evaluation revealed that when the osteotomy cuts were made at a safe distance (3-5 mm) from the apices of roots, neither important pulpal degeneration nor loss of teeth occurred. Even two of the teeth whose apices were cut off had completely healthy pulpal and periapical tissues. The periodontium in almost all of the cases was also found to be healthy.

Animals↗

PubMed2004

Digital radiograph registration and subtraction: a useful tool for the evaluation of the progress of chronic apical periodontitis.

The purpose of this study was to evaluate the suitability of a digital radiograph registration and subtraction software for a sensitive and reliable assessment of the progress of chronic apical periodontitis. Ninety cases of teeth with chronic apical periodontitis have been studied. In each case, a preoperative radiograph was taken, root canals were prepared, and a Ca(OH)2 paste was placed in the root canals. Radiographic control and replacement of Ca(OH)2 paste took place at 15-day intervals. The root canals were obturated 1.5 months after the first appointment. Recall radiographs were taken 0.5, 1.5, 3, 6, and 12 months after the obturation. All radiographs were taken for each case under constant conditions by using a direct digital radiography system. In each case, the preoperative, postoperative, and control and recall radiographs were digitally registered and pairwise subtracted. The resulting images were further processed by using contrast enhancement and pseudocoloring methods. Changes to the periapical tissue structure were easily detectable by using the above-mentioned methodology, even during short time intervals.

Calcium Hydroxide↗

PubMed2003

Measurement of periapical pressure created by occlusal loading.

AIM: To develop an in vitro model in which the pressure in the periapical tissues can be measured during loading. METHODOLOGY: Extracted human maxillary central incisors were embedded in resin blocks that had physical characteristics similar to those of bone and periodontal ligament. Each tooth was loaded with 20, 40, 50, 60, 75, 85, 100, 200, 300 and 450 N vertical forces from the incisal edge of the crown on three consecutive occasions. A minute resistor embedded in the periapical space was used to detect apical pressure changes during occlusal loading. The ratio of apical pressure changes (DeltaP) to the loading force changes (DeltaF) was calculated. RESULTS: The periapical pressure detected was in direct proportion to the loading force. The mean value of DeltaP/DeltaF was 5.994 kPa N-1 (SD = 2.04). CONCLUSIONS: Direct proportionality was found between the coronal loading and the apical hydrostatic pressure. The DeltaP/DeltaF ratio determined in this study makes it easier to estimate the apical hydrostatic pressure values during occlusal loading of single-rooted teeth. In this study, the apical pressure generated under occlusal loading was the same magnitude as that estimated with the finite element method.

Alveolar Process↗

PubMed1991

Kinetics of bone-resorbing activity in developing periapical lesions.

The presence and kinetics of bone-resorbing activity in periapical lesions were studied with a rat model system. Lesions were found to expand most rapidly between induction on day 0 and day 15 ("active phase"), with enlargement occurring at a slower rate thereafter (days 20 and 30, "chronic phase"), as assessed by measurement of magnified radiographs and automated image analysis. Pooled extracts of periapical tissues obtained on day 15 contained significant levels of bone-resorbing activity, as determined by 45Ca release from pre-labeled fetal rat long bones. Normal rat dental pulp and periodontal ligament contained no activity. In two kinetic experiments, highest levels of bone-resorbing activity were detected in tissues on days 10 (10.4% and 11.6% specific 45Ca release/mg/mL) and 15 (8.9%). Activity declined thereafter on day 20 (4.4% and 6.1%) to near baseline levels by day 30 (1.4% and 3.3%). Identical levels of resorbing activity were found in the presence or absence of polymyxin-B, an inhibitor of bacterial lipopolysaccharide. These findings demonstrate that bone-resorbing activity is temporarily related to periapical bone destruction and suggest that this model may be useful for studies of mediators that are involved in the pathogenesis of inflammatory bone resorption.

Animals↗