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PubMed2002

Effect of methotrexate-induced neutropenia on pulpal inflammation in rats.

The purpose of this study was to determine the role of neutropenia in pulpal inflammation. We investigated the effect of methotrexate-induced neutropenia on pulpal inflammation in rats. Pulpal inflammation was produced by pulpal exposure. Thirty-six rats were divided equally into control and experimental groups. The control animals received no injection, whereas the experimental animals were injected with 7.5 mg/kg of methotrexate once a day for 3 days before the pulpal exposure. The pulp was exposed in the mandibular first molar of all animals, and the exposed areas were left open. Animals were killed at 2, 4, and 7 days thereafter. Before they were killed, peripheral blood was taken. The number of total leukocytes and neutrophils in the peripheral blood of experimental animals was significantly decreased compared with those of control animals. The methotrexate-induced neutropenia resulted in the initiation of a bacterial invasion into the pulpal tissue and an increase in pulpal necrosis, as well as lessened abscess formation. Histometrically, the area of pulpal necrosis in experimental animals was significantly greater than that in the control animals. Immunohistochemically, the neutropenia resulted in inhibition of the infiltration by neutrophils. These results suggest that the neutrophil plays an important role in the defense against bacteria in pulpal tissue.

Animals↗
PubMed1977

Tissue response to silicone rubber when used as a root canal filling.

To test the tissue compatibility of silicone rubber when it is used as a root canal filler, excess material was intentionally forced into the apical tissues in primates. The tissue response was one of general acceptance, with the usual response being fibrotic encapsulation. A low degree of inflammation was noted. Further studies are in progress.

Animals↗
PubMed1989

[Electron microscopic study on the tissue reaction after root canal filling following artificial periapical lesions--about periapical lesions induced by carrageenin].

Although a number of reports on the formation of periapical lesions have been down, little study on the healing stage of this one is seen. Therefore, the aim of this study was to investigate the changes of the fine structure of the healing stage of the artificial periapical lesions after root canal filling and to make an experimental model for the further screening test of various kinds of medicaments and materials for root canal treatment and root canal filling. In this study, the first mandibular molars of male Wistar strain rats were used. Periapical lesions were induced by 0.5% carrageenin and after three weeks, the root canals of the first molars were filled with gutta-percha points and sealers. Then, the healing stage of the periapical lesion was observed light microscopically, electron-microscopically and enzyme (alkaline phosphatase, ALP, and acid phosphatase, ACP)-histochemically. The results were as follows after the root canal filling with carrageenins: 1. At 1 to 7 days, a great number of neutrophils and histiocytes were observed and expansion of periapical lesions caused by the irritation followed by root canal filling was observed. 2. At 2 to 3 weeks, a great number of leukocytes, histiocytes and fibroblasts were observed in the vicinity of the root apex. 3. At 4 to 5 weeks, a great number of histiocytes and mast cells were observed and granulated tissues of the periapical lesions had a tendency to become fibrosis and new calcified cement increased at the root apex. 4. At 7 to 10 weeks, the fibroblast granulation tissue around the periapical lesions synthesized active collagen fibers and the deposition of new alveolar bone was seen within the resorbed alveolar bone. 5. At 15 to 20 weeks, the periapical lesions could be thought to be healing histopathologically although some of inflammatory cells were seen 20 weeks after treatment. 6. At 10 weeks, strong positive responses of ALP were recognized. At 20 weeks, the general appearance of both the ALP and ACP staining showed almost the same response as that of normal periodontium. 7. As for the prognosis, "over filling" showed better healing than that of "under filling". 8. In the case which the root apex was fractured, inflammation lasted for a long period.

Animals↗
PubMed1990

[Bacterial recolonization in the guided regeneration of the inter-radicular periodontal tissues].

The present experimental study has been undertaken in order to analyse clinically and microbiologically the formation of new periodontal attachment in class II furcation lesions in mandibular molars, comparing healing after surgical conventional therapy and after guided periodontal tissue regeneration technique using non-resorbable membranes and evaluating at the same time, with cultural anaerobic technique, the influence on healing of the bacterial recolonization of some periodontally pathogenic species. Clinical results have demonstrated that, after therapy, may occur a certain discrepancy between soft and hard tissue regeneration and that the bone tissue shows a different pattern of apposition in the horizontal and vertical direction. Microbiological data have underlined the significance of surgical instrumentation in the guided inter-radicular periodontal tissue regeneration and have confirmed the necessity of maintaining the healing sites free from the main periodontal pathogens.

Adult↗
PubMed1999

Response of periradicular tissues to growth factors introduced into the surgical site in the root-end filling material.

AIM: The objective of this study was to evaluate the healing of the periradicular tissues when exogenous growth factors were delivered to the respected root-end. The healing response was compared with that when Diaket was used as a control. METHODOLOGY: Non-surgical root canal treatment was performed on mandibular teeth in mongrel dogs. Surgical treatment followed and included root-end resection and root-end cavity preparation. Insulin-like growth factor in combination with platelet-derived growth factor, or fibroblast growth factor alone, were then placed in the root-end preparations on a polylactic acid carrier (Atrisorb) with or without the incorporation of the carrier tetracalcium phosphate. The healing was evaluated at 60 days with regard to presence of inflammatory response, bone regeneration, periodontal ligament formation and cementum formation. RESULTS: Osseous regeneration in the excisional would and periodontal formation were significantly greater when Diaket was used as the root-end filling material. Likewise, cementum deposition occurred significantly more frequently in the Diaket group (P < 0.05). The polylactic carrier Atrisorb remained in the surgical sites for the duration of the study. CONCLUSIONS: The use of specific growth factors, FGF and a combination of IGF/PDGF, delivered to the prepared root end in a collagen carrier did not initiate the desired periradicular tissue response of regeneration. Diaket, as used in this study, did stimulate a periradicular tissue response compatible with regeneration.

Analysis of Variance↗
PubMed1985

Vital apicoectomy of the teeth: a 1-4 week histopathological study in Macaca mulatta.

Several studies have reported devitalization of teeth following surgical procedures in the area of the root apices. The purpose of this investigation was to observe the 1-4-week wound healing pattern in monkey dental tissues following intentional vital apicoectomy (IVA). Two adult Macaca mulatta were used in this study. All of the teeth were surgically transected within the apical one-third with a bur. The soft tissues were then closed. At death, a maxillary and a mandibular quadrant for 1, 2, 3 and 4 weeks following surgery were obtained after vascular perfusion. Each quadrant was demineralized in EDTA, processed, serially sectioned at 7 microns and alternately stained with hematoxylin and eosin, Preece's modified trichome, and McKay's bacterial stains. Examination of sequential IVA cuts showed an initial disruption of the pulpal neurovascular supply resulting in pulpal necrosis. The pulpal tissues underwent a process of replacement with PDL-like connective tissues and deposition of cementum on all cut dentin surfaces of the tooth roots as well as in some of the pulp chambers. No abscesses, external resorption or ankylosis were found.

Alveolar Process↗
PubMed2000

Preliminary report on the effect of Nd: YAG laser irradiation on canine tooth pulps.

OBJECTIVE: To study the effects of Nd: YAG laser irradiation on the canine tooth pulps. METHODS: The crown pulp of dog was exposed and excised by ND: YAG laser irradiation. Histopathological examination was used to check changes of the tissues in root canal and periodontium. RESULTS: The pulp of the crown could be successfully excised by Nd: YAG laser without harmful changes in either root canal or periodontal tissues. CONCLUSION: This study may provide an experimental basis for the clinical possibility of crown pulp excision by using Nd: YAG laser irradiation.

Aluminum Silicates↗
PubMed1991

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.O. 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.O., 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.O., severe.

Animals↗
PubMed2006

Haemostatic agents used in periradicular surgery: an experimental study of their efficacy and tissue reactions.

AIM: To evaluate the haemostatic efficacy and the histologic tissue responses after the application of different haemostatic agents used in periradicular surgery. METHODOLOGY: The study was conducted in the calvarium of six rabbits. Standardized bone defects (diameter 4 mm) were trephined, and different haemostatic agents were applied and compared with control defects: bone wax (left for 10 min), Stasis (ferric sulphate, left for 5 s), Expasyl (aluminium chloride, left for 2 min and left permanently in situ), and a combination of Expasyl (2 min) and Stasis (5 s). The sites were photographed before the application and after the removal of the haemostatic agents. Three independent examiners judged the initial and final bleeding (on the photographs) using a bleeding score for each site and treatment. The results were compared using Wilcoxon's signed rank test. For the histologic analysis, three animals were killed after 3 weeks and three animals after 12 weeks. Transverse, nondecalcified sections were stained with combined basic fuchsin and toluidine blue for descriptive histology. RESULTS: The most efficient haemorrhage control was provided by Expasyl in combination with Stasis and by Expasyl alone, whereas bone wax had the weakest bleeding reduction effect. The histologic analysis after 3 weeks demonstrated an inflammatory and foreign body tissue response towards all haemostatic agents. At 12 weeks, this tissue response was less pronounced but still present in sites treated with bone wax or Expasyl. In general, the inflammatory tissue reactions were limited to the bone defects, and never extended into the surrounding tissues. CONCLUSIONS: Expasyl alone or in combination with Stasis appeared to be the most efficient of tested agents to control the bleeding within the bony defects created in a rabbit calvarium model.

Aluminum Chloride↗
PubMed1994

Interleukin 1-beta in symptomatic and asymptomatic human periradicular lesions.

Interleukin 1 beta (IL-1 beta) has been shown to be a potent mediator of bone resorption and has been implicated in resorption in periradicular lesions. In this study we compared the local concentrations of IL-1 beta in symptomatic and asymptomatic human periradicular lesions. Periradicular tissues from patients with symptomatic and asymptomatic lesions were obtained and stored at -70 degrees C. Pulpal tissues from unerupted third molars and chronically inflamed gingival tissues were also obtained and used as negative and positive controls, respectively. Tissue samples were homogenized, and supernatants were assayed for IL-1 beta by the enzyme-linked immunosorbant assay. Significantly higher levels of IL-1 beta were found in symptomatic and asymptomatic lesions and inflamed gingival tissues compared with uninflamed pulp tissues. There was a trend toward higher levels of IL-1 beta in symptomatic lesions compared with asymptomatic lesions, but the difference was not significant. The results suggest that IL-1 beta may play a significant role in the pathogenesis of human periradicular lesions.

Analysis of Variance↗
PubMedDate not supplied

Evaluation of decalcified allogenic bone matrix grafts in and around root apices. A histological study.

Decalcified Allogenic Bone grafts were implanted in and around eighteen root apices after apicoectomy. The procedure was carried out on eighteen rabbits, dividing them into three groups of six rabbits each. The animals were sacrificed after 48-72 hours, 8-10 days & 8-10 weeks period of interval. Result of the present investigation reveal that DABM grafts stimulate osteogenesis and cementogenesis after the initial phase of inflammation. Tissues simulating bone and cementum appear at the apical end, speculating that the grafts would certainly result in physiological sealing of root apices. The possibility of saving the life of non vital teeth with or without wide apical foramen will enhance in future.

Animals↗
PubMed1997

Endodontic considerations in the geriatric patient.

Endodontic needs of today's and tomorrow's growing older adult population present increasing challenges for dental care providers. Biologic and anatomic differences in the dental tissues between older and younger patients must be understood and considered in treatment planning and performance for appropriate endodontic procedures. These differences generally do not contraindicate treatment, which, when performed correctly, will be successful in the elderly patient.

Adult↗
PubMed2000

Necrosis of the gingiva caused by calcium hydroxide: a case report.

CASE REPORT: The present case demonstrates the possible detrimental effect of an overextension of a calcium hydroxide intracanal dressing into the periradicular and soft tissue after iatrogenic buccal root perforation of a maxillary central incisor. At first this perforation was not recognized by the dentist, which resulted in the introduction of a large amount of non-setting calcium hydroxide paste under the gingival tissues through a dehiscence on the buccal side of the root. This report describes the consequences and management of the necrosis of the buccal gingiva and mucosa, and the subsequent treatment and follow-up of the root perforation.

Adult↗
PubMed2003

Twelve-year follow-up of an autogenous mandibular canine transplant.

Transplantation is the transfer of tissue or an organ from 1 site to another in the same person or between different persons. A transplantation in which donor and recipient are the same individual has been termed autogenous transplantation, autoplastic transplantation, or autotransplantation. The purpose of this report was to describe a patient undergoing autotransplantation of an impacted mandibular canine to its normal position in the mandible and the 12-year follow-up. Five years after the surgical procedure, the patient presented with pulp canal obliteration in the autotransplanted tooth. Twelve years after the autotransplantation, the tooth position was stable despite pulp canal obliteration, but with no sign of inflammatory resorption or a periapical lesion. In addition, there was no sign of replacement resorption (ankylosis). The endodontic literature has shown that the prognosis of patients undergoing autotransplantation may be good under specific considerations. Therefore, the technique may be a treatment plan option for the replacement of missing teeth.

Child↗
PubMed2002

Comparison of Diaket and MTA when used as root-end filling materials to support regeneration of the periradicular tissues.

AIM: The objective of this study was to evaluate on a comparative basis the potential for mineral trioxide aggregate (MTA) and Diaket to promote periradicular tissue regeneration when used as surgical root-end filling materials. METHODOLOGY: Seven dogs weighing between 15 and 25 kg were anesthetized prior to having the root canals of their mandibular premolars accessed, cleaned, shaped and obturated. Coronal access cavities were restored with IRM. Surgical access to the root ends was established and the root ends were resected and prepared with ultrasonic tips. Root-end fillings of either MTA or thickly mixed Diaket were randomly assigned to the preparations. Reflected tissues were repositioned and sutured with 4-0 vicryl sutures. Sixty days postsurgery, the animals were killed, perfused with 10% neutral buffered formalin and the third and fourth premolars removed in block sections. The specimens were demineralized and sectioned at 6-microm intervals for histological assessment. Sections were stained with either haematoxylin and eosin or Gomori's one step trichrome stain and examined under the light microscope. All evaluations were made by two calibrated examiners and gradings were scored based on established criteria. The raw data was evaluated statistically using anova after adjusting for the animal block effect. RESULTS: Statistical evaluation indicated that there were no statistical differences between the observed regenerative responses of the tissues to the two root-end filling materials. CONCLUSIONS: Both Diaket and MTA can support almost complete regeneration of the periradicular periodontium when used as root-end filling materials in periradicular surgery on noninfected teeth.

Aluminum Compounds↗
PubMed1999

Reaction of dogs' teeth to root canal filling with mineral trioxide aggregate or a glass ionomer sealer.

This study was conducted to observe the reaction of apical tissues of dogs' teeth after root canal filling with gutta-percha and mineral trioxide aggregate (MTA) or a glass ionomer (Ketac-Endo) as a sealer. The root canals were instrumented and filled by the lateral condensation technique with the sealers studied. Animals were killed 6 months later, and the specimens were removed and prepared for histological analysis. Results showed no inflammatory reaction of apical tissue and total closure of the apical foramen of all the teeth sealed with MTA. The teeth sealed with Ketac-Endo showed two cases of partial closure and different degrees of chronic inflammatory reaction. In conclusion, MTA exhibited better biological properties than Ketac-Endo.

Aluminum Compounds↗
PubMed1998

Air pressures developed beyond the apex from drying root canals with pressurized air.

Air introduced into tissues during invasive procedures can be harmful. Endodontic treatment is not frequently associated with this phenomenon, but serious results can occur if air forced into tissues impinges on critical anatomical structures and/or carries infection into deeper areas. Extracted teeth were connected to a pressure gauge during and after canal instrumentation and pressures measured. Also, a fresh porcine jaw was instrumented in the presence of a radiopaque tracer during air drying. Significant pressures were detected beyond the apex of the roots, especially with root apical diameters of file sizes larger than 20.

Air Pressure↗