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PubMed1998

The management of thermomechanically compacted gutta percha extrusion in the inferior dental canal.

Endodontic material inadvertently forced into the inferior dental canal during root-canal therapy can cause damage to the underlying nerve. The effect of toxic filling materials on nervous tissues has been well publicised, however, the thermal and pressure changes produced by chemically bland materials has not been adequately highlighted. In the case reported, thermoplasticised gutta percha was inadvertently introduced into the canal during endodontic treatment of a lower molar. Factors affecting the outcome are discussed and guidelines are presented for the management of such a case with reference to surgery against observation.

Adult↗

PubMed2001

Effects of the multiple-piece maxillary osteotomy on the periodontium.

Clinical indications exist for both the surgically assisted rapid maxillary expansion (SARME) and the multiple-piece maxillary osteotomy (MPMO). Recent trends, however, imply that the SARME combined with a subsequent 1-piece osteotomy can supplant the use of the MPMO. Those favoring the SARME frequently site morbidities associated with the MPMO. Major reported complications include loss of dentoalveolar segments, teeth, and oronasal or oroantral communication. Relapse, tooth devitalization, and damage to the periodontium, including bone loss and soft tissue alteration, comprise the minor morbidities. If these can be avoided or minimized, then the use of the MPMO for its inherent advantages over the SARME in certain clinical situations may be indicated The purpose of our study was to critically evaluate the periodontium following the use of the MPMO to ascertain if minor morbidities are inherent to the procedure, and to quantify them. Records of 24 MPMO patients were reviewed, ranging from 3 to 24 months after surgery. A specific surgical technique was utilized for all patients, including bone grafting. The vertical segmental osteotomy sites varied and were recorded for comparison. Periodontal probing depths at the segmental osteotomy sites were compared with the adjacent interproximal spaces of each patient. Independent dental examiners were used to review photographs and periapical radiographs to compare the papillae and alveolar bone height, respectively, at the osteotomy site versus the neighboring interproximal areas. A paired t test was used to compare probing depth measurements at the vertical osteotomy site and neighboring interproximal sites. The mean difference between these two sites was 0.01 mm with a standard deviation of 0.25 mm. This was not statistically significant. Statistical analyses were also performed to compare these probing depth differences at varying sites in the maxilla, and to compare probing depth differences to gender, total number of osteotomies performed on each patient, estimated blood loss, and length of procedure. These results were not statistically significant. Independent examiners found no difference in gingival architecture or alveolar bone levels when comparing vertical osteotomy sites to neighboring interproximal sites. This study showed that damage to the periodontium at vertical osteotomy sites was minimal, and not a reason to avoid use of the multiple-piece maxillary osteotomy.

Adolescent↗

PubMed1996

Effect of various sealers with gutta-percha as root-end fillings on healing after replantation.

This study examined histologically the effect of three sealers used with gutta-percha as root-end fillings placed in a replantation model. A total of 14 molar teeth were used in seven monkeys. After extraction, root ends were resected, the canals contaminated with oral bacteria, root-end cavities prepared, and fillings of gutta-percha and sealer placed prior to replantation. After 8 weeks the teeth and surrounding jaw were removed and prepared for histological examination. Six roots filled with gutta-percha plus a fortified zinc oxide-eugenol cement (IRM), 13 with gutta-percha plus zinc oxide-eugenol (EP), and eight with gutta-percha plus Kloropercha, were available for examination. The tissue response to gutta-percha with either zinc oxide material was characterized by little or no inflammation of limited extent. In contrast, more severe inflammation was observed against root ends filled with gutta-percha and Kloropercha. Gutta-percha plus IRM or zinc oxide-eugenol had a much more favourable response than that to amalgam reported previously in a similar experiment.

Animals↗

PubMed1995

Investigation of mineral trioxide aggregate for root-end filling in dogs.

Numerous compounds have been used as root-end filling materials. Based on the results of in vitro and intraosseous implantation tests, mineral trioxide aggregate (MTA) seems to have potential as a root-end filling material. The purpose of this study was to examine the periradicular tissue response of dogs to MTA and amalgam. Lesions were developed in periradicular tissues of 46 roots in six beagle dogs. The canals on half of the roots were instrumented and obturated with gutta-percha and sealer, and their access cavities were sealed with MTA. The remaining root canals were instrumented and obturated with gutta-percha and sealer, and their access cavities were sealed with MTA. The remaining root canals were instrumented and obturated with gutta-percha without root canal sealer. The access cavities of the teeth in this group were left open to the oral cavity. After surgical resection of roots, half of the root-end cavities were filled with amalgam and the rest with MTA. The periradicular tissue response of the dogs was evaluated histologically 2 to 5 and 10 to 18 wk following periradicular surgery. Statistical analysis of the results showed less periradicular inflammation and more fibrous capsules adjacent to MTA, compared with amalgam. In addition, the presence of cementum on the surface of MTA was a frequent finding. The results show that MTA can be used as a root-end filling material.

Aluminum Compounds↗

PubMed1997

Direct digital radiography for the detection of periapical bone lesions: a clinical study.

The aim was to compare the observer performance of direct digital radiography, with and without image processing, with that of conventional radiography, for the detection of periapical bone lesions. For 50 patients, a conventional periapical radiograph using E-speed film was taken. Then, a direct digital image of the same area was made. The images presenting the periapical bone tissue of 59 roots were assessed by seven observers using a 5-point confidence scale. The digital images were first presented as original images, with default contrast and brightness set by the computer system. Following this, the observers were allowed to use the processing facilities for greyscale treatment. The results for original and processed direct digital images and for conventional radiographs were compared by Receiver Operating Characteristic (ROC) analysis. The area under the ROC curve, calculated as P(A) value, was 0.88 for conventional film, 0.82 for original digital images and 0.78 for processed images. Corresponding Az values were slightly higher, 0.89, 0.84 and 0.81. Statistically significant differences between ROC areas calculated as P(A) values for the methods were found. Comparison between Az values showed no significant differences between conventional radiographs and original digital images, whereas the difference between Az values for original and processed digital images was still significant. It was concluded that conventional film radiography performed slightly better for the detection of periapical bone lesions than direct digital radiography and that image processing did not improve the observer performance.

Alveolar Bone Loss↗

PubMed1987

Tissue response to retrograde root fillings in the ferret canine: a comparison of a glass ionomer cement and gutta-percha with sealer.

Tissue healing was compared after apicectomy and filling of ferret lower canines with glass ionomer (Ketacfil) or gutta-percha/sealer (Tubliseal). Both materials provoked an inflammatory response after 7 days, but the response to glass ionomer was less severe. The response after 28 days was different. Mild inflammation related to the gutta-percha was still present, but no inflammation was found in relation to the glass ionomer. Bone infill was quite advanced in all specimens at 28 days but was more complete in the glass ionomer specimens, with intimate contact between the bone and cement.

Animals↗

PubMed1977

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

The anterior teeth of five adult monkeys were divided into two groups. In one group the pulps were removed and the teeth were left open to oral fluids. The other group had vital pulps. Five teeth were designated as controls. The pulp canals of both groups were debrided, filed, and flushed thoroughly. In the two experimental groups (vital and pulpless), the apical third of the canal was filled with Ca(OH)2. In the control group no medication was placed in the canal. The coronal access of the canals of all groups was sealed with amalgam. After 270 to 330 days, the teeth were sectioned and examined histologically. No apical bridging was observed in any group.

Animals↗

PubMed1997

Bone-resorptive cytokine gene expression in periapical lesions in the rat.

Periapical bone destruction is an important pathogenic sequela of pulpal infection. Recent findings from this laboratory have demonstrated that most bone-resorbing activity in extracts of rat periapical lesions can be neutralized by an anti-interleukin (IL)-1 alpha antiserum. To further clarify pathogenic mechanisms, bone-resorptive cytokine messenger RNA (mRNA) expression was analyzed in developing rat periapical lesions. The molar teeth of 20 Sprague-Dawley rats were surgically exposed and left open to permit infection from the oral environment. Total cell RNA was isolated from periapical granuloma tissue obtained on days 3, 7, 15 and 30 after exposure. mRNA for IL-1 alpha, IL-1 beta and tumor necrosis factor alpha (TNF-alpha) was amplified by reverse transcription polymerase chain reaction, and levels were approximated by comparison to the parallel amplification of the housekeeping gene glyceraldehyde phosphate dehydrogenase. IL-1 alpha and TNF-alpha mRNA were both highly expressed beginning on day 7, increased on day 15, and declined somewhat on day 30. In contrast, IL-1 beta mRNA was expressed at much lower levels, but with similar kinetics. The kinetics of steady state IL-1 alpha and TNF-alpha mRNA levels were confirmed using the quantitative RNase protection assay, whereas IL-1 beta mRNA could not be detected by this technique. IL-1 alpha mRNA-expressing cells were identified using in situ hybridization and included infiltrating macrophages, as well as resident fibroblasts, endothelial cells and osteoclasts. These results demonstrate that the IL-1 alpha and TNF-alpha genes are highly expressed in developing periapical lesions in the rat and confirm previous studies at the protein level in this model.

Alveolar Bone Loss↗

PubMed1979

[Endodontics--a literature review. Continuation of part II].

A survey of physical and biological properties of well-known root canal filling materials are discussed and the following conclusions were drawn: --No root canal filling material fulfils all requirements of an ideal sealer. Those materials, which perfectly seal the root canal and also show minimal periradicular tissur reaction, are recommended in Endodontics. --During setting time, all sealers are more or less toxic to the periradicular tissue. Materials which contain paraformaldehyde and lead exhibit a strong and persistent toxicity. --The tissue reaction of root canal filling materials is only slight when the root canal is underfilled. Ideally, in vital cases, the root canal should be filled to the dentine-cemental junction (approx. 1 mm short of the apex), in necrotic cases to the apical foramen. --Neither a root canal cement nor a guttapercha cone will perfectly seal a root canal alone. The combination of the two materials is recommended. --Silver cones are indicated only in narrow, tortuous canals. --Success of root canal therapy depends on various factors, primarily however on thorough root canal débridement.

Cells, Cultured↗

PubMed1996

Haemostasis in periradicular surgery.

The successful performance of endodontic surgical procedures is predicated on many factors. However, the ability of achieve sustained tissue haemostasis in the surgical site is crucial to the performance of these procedures. This achievement improves vision in the surgical site, minimizes surgical time, enhances the surgical procedures (root-end resection, preparation and filling), and reduces surgical blood loss, postsurgical haemorrhage and postsurgical swelling. A multitude of materials have used in dentistry and medicine to achieve both generalized and localized haemostasis, many without full assessment of their biological implications. The purpose of this paper is to provide a thorough and critical review of these materials from the perspective of surgical endodontics, highlighting their development, application and potential role in achieving proper haemostasis.

Antifibrinolytic Agents↗

PubMed1999

Infection-stimulated infraosseus inflammation and bone destruction is increased in P-/E-selectin knockout mice.

Infections of the dental pulp commonly result in infraosseus inflammation and bone destruction. However, the role of phagocytic leucocytes in the pathogenesis of pulpal infections has been uncertain. In this work we used P/E-/- selectin-deficient mice, which lack rolling adhesion of leucocytes to endothelium and mimic the human syndrome, leucocyte adhesion deficiency II (LAD-II), to test the hypothesis that phagocytic leucocytes protect against pulpal infection and subsequent periapical infraosseus bone resorption. P/E-/- mice and P/E+/+ wild-type controls were subjected to surgical pulp exposure, and both groups were infected with a mixture of pulpal pathogens including Prevotella intermedia, Fusobacterium nucleatum, Peptostreptococcus micros and Streptococcus intermedius. Animals were killed after 20 days, and the extent of infraosseus bone destruction was quantified by histomorphometry. In two separate experiments, P/E-/- mice had significantly greater bone resorption than P/E+/+ controls. The increased bone destruction correlated with a twofold decrease in polymorphonuclear (PMN) infiltration into periapical inflammatory tissues of P/E-/- mice. P/E-/- mice had higher tissue levels of the bone resorptive cytokine, interleukin (IL)-1alpha. Tissue levels of IL-2, IL-4, IL-10, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were all higher in P/E-/- mice, but the increases were not statistically significant. Only IL-12 was higher in P/E+/+ mice, possibly reflecting a greater number of infiltrating monocytes in wild-type mice. These findings demonstrate that phagocytic leucocytes are protective in this model, and suggest that elevated expression of inflammatory cytokines is responsible for the observed bone destruction.

Animals↗

PubMed1997

Histologic assessment of mineral trioxide aggregate as a root-end filling in monkeys.

Mineral Trioxide Aggregate (MTA) has been shown in a number of experiments to be a potential root-end filling material. The purpose of this study was to examine the periradicular tissue response of monkeys to MTA and amalgam as root-end fillings. The pulps were removed from all the maxillary incisors of three monkeys. The root canals were prepared and filled with laterally condensed guttapercha and sealer, and the access cavities were restored with amalgam. Buccal mucoperiosteal flaps were raised, and root-end resections were performed before root-end cavity preparation with burs. The root-end cavities in half of the teeth were filled with MTA, while amalgam was placed in the other cavities. After 5 months the periradicular tissue response was evaluated histologically. The results showed no periradicular inflammation adjacent to five of six root ends filled with MTA; also five of six root ends filled with MTA had a complete layer of cementum over the filling. In contrast, all root ends filled with amalgam showed periradicular inflammation, and cementum had not formed over the root-end filling material, although it was present over the cut root end. Based on these results and previous investigations, MTA is recommended as a root-end filling material in man.

Aluminum Compounds↗

PubMed1982

Endotoxic activity in periapical lesions.

Thirty tissue samples were examined histologically and classified as being inflamed (apical granulomas) or noninflamed (scars or noninflamed cysts). The samples were then homogenized in pyrogen-free water and treated to remove interfering substances. The presence of endotoxin was then determined by means of the limulus assay; 75 percent of the inflamed tissues were positive for endotoxin, while only 20 percent of the noninflamed tissues contained endotoxin. The presence of endotoxin was thus highly correlated (p = 0.015) with the presence of inflammation in these tissues.

Endotoxins↗

PubMed1993

Wound healing following demineralization of resected root ends in periradicular surgery.

The objective of this study was to determine the effect of demineralization of resected root ends on the temporal and qualitative healing of the dentoalveolar (apical attachment apparatus) and alveolar (osseous) tissues in the excisional wound site created during periradicular surgery. Root end resections to orthograde gutta-percha obturations were performed on the mandibular premolars of six mongrel dogs. Twenty-four experimental root ends were demineralized by citric acid burnishing of the resected surfaces. The remaining 24 standard treatment root ends were not demineralized. Microscopic evaluations at postsurgical intervals from 4 to 45 days revealed that the demineralized root ends were associated with more rapid and complete healing than the nondemineralized root ends. It is proposed that demineralization enhances cementogenesis, the key to dentoalveolar healing, by removing the smear layer barrier and exposing the organic component (collagen fibrils) of resected cementum and dentin.

Acid Etching, Dental↗

PubMed2000

IL-10, but not IL-4, suppresses infection-stimulated bone resorption in vivo.

Periapical bone resorption occurs following infection of the dental pulp and is mediated mainly by IL-1alpha in the murine model. The production and activity of IL-1alpha is modulated by a network of regulatory cytokines, including those produced by Th1 (pro-inflammatory) and Th2 (anti-inflammatory) subset T cells. This study was designed to assess the functional role of the Th2-type cytokines IL-4 and IL-10 in infection-stimulated bone resorption in vivo. The dental pulps of the first molars were exposed and infected with a mixture of four common endodontic pathogens, and bone destruction was determined by micro-computed tomography at sacrifice on day 21. The results demonstrate that IL-10(-/-) mice had significantly greater infection-stimulated bone resorption in vivo compared with wild-type mice (p < 0.001), whereas IL-4(-/-) exhibited no increased resorption. IL-10(-/-) had markedly elevated IL-1alpha production within periapical inflammatory tissues (>10-fold) compared with wild type (p < 0.01), whereas IL-4(-/-) exhibited decreased IL-1alpha production (p < 0.05). IL-10 also suppressed IL-1alpha production by macrophages in a dose-dependent fashion in vitro, whereas IL-4 had weak and variable effects. We conclude that IL-10, but not IL-4, is an important endogenous suppressor of infection-stimulated bone resorption in vivo, likely acting via inhibition of IL-1alpha expression.

Animals↗

PubMed1998

Histological evaluation of the response of apical tissues to glass ionomer and zinc oxide-eugenol based sealers in dog teeth after root canal treatment.

The object of the study was to compare two commercial root canal sealers: Ketac-Endo (a glass ionomer cement) and Fill Canal (a zinc oxide-eugenol cement). A total of 34 root canals from dog premolars with vital pulps were used. After instrumentation, the root canals were sealed with Ketac-Endo and Fill Canal cements using gutta-percha and a lateral condensation technique. After 270 days the animals were sacrificed with an anesthetic overdose and the maxillae and mandibles were removed and fixed in formalin for 48 h. After routine histological processing the sections were stained with hematoxylin-eosin and Mallory trichrome stains. Microscopic analysis revealed that Ketac-Endo cement presented better results than Fill Canal cement.

Animals↗

PubMed1997

A histological and quantitative histomorphometric study of apexification of nonvital permanent incisors of vervet monkeys after repeated root filling with a calcium hydroxide paste.

The purpose of this study was to compare the effect of a monthly refilling of the root canals with calcium hydroxide paste with a single packing or replacement of the paste at 3 months on the apexification of nonvital maxillary incisors of vervet monkeys. Forty-eight maxillary incisors from 12 monkeys were used following radiographic determination that root development was incomplete. The pulps were extirpated under general anesthesia and the root canals filed and cleaned. The root canals were filled with a commercial calcium hydroxide paste, Calxyl, and a temporary cavity filling placed. Twelve teeth were left without further treatment. The calcium hydroxide paste was replaced in 12 teeth after a 3-month interval, and in the remaining 24 teeth the calcium hydroxide root filling was replaced five times at monthly intervals. The monkeys were killed after 6 months, and blocks of the teeth and surrounding tissues were embedded, decalcified and 6 microns serial sections prepared and stained. The sections were studied histologically to evaluate 11 parameters. Significant differences were found in the amount of calcium hydroxide at the apices, the presence of new cementum on the roots and the degree of inflammation, all of which were better in the monthly refill group. Histomorphometric measurements to evaluate the obturation of the open apices and the volume of new primary osteocementum showed no significant difference between the three groups. It was suggested that after the initial root filling with calcium hydroxide there was nothing to be gained by repeated root filling either monthly or after 3 months, for at least 6 months.

Analysis of Variance↗

PubMed1987

Observer strategy and the radiographic classification of healing after endodontic surgery.

An observer strategy involving trained and experienced examiners was used in a large series of endodontic surgery cases, evaluated radiographically 1 year after the operation. The cases were grouped in 1 of the following 4 healing groups; complete healing, incomplete healing (scar tissue), uncertain healing and unsatisfactory healing (failures). The radiographs were first examined separately by an oral surgeon and an endodontist. Deviating cases were subjected to joint evaluation. The overall agreement before joint interpretation was satisfactory: 63% when corrected for chance agreement. Agreement after joint evaluation reached 94% of the total material. Disagreement and difficult borderline cases were judged by an oral radiologist. He was more pessimistic than the 2 main examiners. The identification of healed cases with apical bone which had not yet obtained normal radiopacity and structure was difficult. Altogether, the observer consistency was satisfactory; the selection of experts increased the chances of "true" diagnoses; the important screening function of the one-year control was confirmed. The applied strategy and the classification are recommended for follow-up studies.

Classification↗