Kerr Sealer Research Articles

Cytotoxicity evaluation of Activ GP and Resilon sealers in vitro

This study is to evaluate the cytotoxicity of Activ GP and RealSeal sealers in a cell culture system in vitro, and to compare them with traditional AH 26 and Kerr sealers. Samples of 0.5 mg freshly mixed or set RealSeal, Activ GP, AH 26, and Kerr sealers were eluted with 200, 400, 800, and 1,200 microL cell culture medium for 24 and 72 hours. L929 cells were seeded into 96-well plates at 3 x 10(4) cells/well and cultured with 100 microL eluate from each eluate group. Cells cultured with culture medium only served as a control. After 24 hours' incubation the cytotoxicity was evaluated by MTT assay. Cell viability was calculated as the percentage of the control group, and the results were analyzed with 1-way analysis of variance. For the freshly mixed sealer, cell viability in the AH 26 group was less than in all of the other 3 sealer groups. The Kerr sealer group had greater cell viability than RealSeal and Activ GP groups. For the set sealer, cell viability in the AH 26 group was greater than in all of the other 3 groups. Cell viability in the RealSeal group was less than in the Kerr and Activ GP groups. Freshly mixed RealSeal and Activ GP sealers have lower cytotoxicity than AH 26 sealer and more cytotoxicity than Kerr sealer. When sealers are set, RealSeal sealer has more cytotoxicity than AH 26 and Kerr sealer. Activ GP sealer has more cytotoxicity than AH 26 and is similar to Kerr sealer.

Apical Leakage of Different Gutta-Percha Techniques: Thermafil, Js Quick-Fill, Soft Core, Microseal, System B and Lateral Condensation with a Computerized Fluid Filtration Meter

To investigate apical leakage of roots filled with 6 different gutta-percha techniques; Thermafil, JS Quick-Fill, Soft Core, Microseal, System B and lateral condensation using a new computerized filtration meter. 60 extracted single rooted teeth were used. Coronal part of each tooth was removed and the root canals were prepared with step-back technique. The roots were randomly divided into six groups of 10 teeth, filled by one of the obturation technique and Kerr sealer. The teeth were kept in 100% humidity for 2 years. After this period, apical parts of roots (10 +/- 0.05 mm) were attached to computerized fluid filtration meter. Apical leakage quantity was determined as mul.cmH(2)O(-1).min(-1). Statistical analysis indicated that Thermafil, Soft Core, Quick-Fill and System B techniques showed lower leakage than Microseal and lateral condensation (P < .05). However, statistically no difference was found among the core techniques and no difference was found between microseal and lateral condensation techniques (P > .05). Thermafil, Soft Core, Quick-Fill and System B techniques showed lower leakage than Microseal and lateral condensation. In addition, this new computerized fluid filtration meter allowed quantitative measurement of leakage easily.

In Vitro Evaluation of the Antimicrobial Effects of a Root Canal Sealer-Antibiotic Combination Against Enterococcus faecalis

The purpose of this in vitro study was to evaluate the antimicrobial effects of five antibiotics when added to Kerr Pulp Canal Sealer EWT against Enterococcus faecalis. Five antibiotics: amoxicillin, penicillin, clindamycin, metronidazole, and doxycycline, were added separately to Kerr sealer. Thirty brain heart infusion agar plates were inoculated with E. faecalis and sterile paper discs containing a sealer-antibiotic combination were randomly assigned to the inoculated plates. Kerr sealer on a sterile paper disc and a blank sterile paper disc served as the controls. Fifteen plates were incubated aerobically and the remaining 15 plates were incubated anaerobically at 37°C. The zones of inhibition were measured at 48 hours. No significant differences (p > 0.05) were found between aerobic and anaerobic groups. The groups were combined and data analysis using a one-way ANOVA and Tukey’s post hoc test was performed. Results revealed that sealer-antibiotic combinations containing amoxicillin, penicillin, clindamycin, and doxycycline had a significant difference (p < 0.001) in the mean zones of inhibition when compared to Kerr EWT sealer alone. No significant differences (p > 0.05) were found between the metronidazole-sealer combinations and Kerr EWT sealer alone.

Resistance of experimental glass ionomer cement sealers to bacterial penetration in vitro

This study evaluated penetration of Enterococcus faecalis in canals filled with glass ionomer cement sealers. Canals of 40 extracted teeth in four equal experimental groups were prepared and filled with KT-308 (experimental sealer) and a single gutta-percha cone (SC), ZUT (KT-308 with an antibacterial agent) and SC, Kerr sealer and vertically compacted gutta-percha (VC), or Kerr sealer with the antibacterial agent and VC. Eight additional teeth served as positive controls and four as negative controls. Pulp chambers were inoculated with E. faecalis, and bacterial penetration through the filled canals was assessed over a period of 90 days. Incidence of bacterial penetration was significantly higher for ZUT/SC than for Kerr sealer/VC (p < 0.05). KT-308/SC did not differ significantly from any other material. The positive controls showed significantly faster penetration than all the other groups (p < 0.05). It was concluded that KT-308 effectively prevented penetration of E. faecalis, whereas ZUT required further development.

Microleakage comparison of thermafil versus vertical condensation using two different sealers

The effect of two different sealers on the quality of the apical seal in roots obturated with Thermafil obturators (Tulsa Dental Products, Tulsa, Okla.) and vertical condensation was tested. Fifty extracted human maxillary anterior teeth were treated with the use of a step-back technique. Teeth were placed into five groups of 10 teeth each. One group served as the positive control. The root canals were obturated using either Thermaseal (Tulsa Dental Products) or Kerr (Kerr Manufacturing Co., Romulus, Mich.) sealer, and Thermafil or vertical condensation. All roots were placed in 1% methylene blue dye for 2 weeks. The roots were cleared, and the degree of linear dye penetration was measured using a Unitron light microscope with a Microcode II digital readout (Boeckeler Instruments, Tucson, Ariz.). The study showed that under in vitro conditions, the Thermafil technique was equivalent in linear leakage to vertical condensation. There were no statistical differences in the mean apical dye penetration between the two sealers or the two obturation techniques.

Comparative tissue tolerance of a new endodontic sealer

An experimental radiopaque resin root canal sealer was tested for tissue biocompatibility in rat connective tissue. The controls were four widely used sealers: Sealapex, Kerr's sealer, AH-26, and Roth's sealer. Polyethylene tubes were filled with the sealers and allowed to set for 24 hours in 100% humidity. Each sealer was implanted in the connective tissue of Sprague-Dawley rats and removed after 3, 10, 20, 30, and 60 days, fixed, and histologically prepared for light microscope evaluation. At each time period there was practically no difference in the reaction of all the sealers. By 60 days, the total picture was one of well-tolerated biocompatibility.

Allotransplantation and autotransplantation of mature teeth in monkeys: the influence of endodontic treatment.

This study investigated the effect of endodontic treatment on root resorption of autotransplanted and allotransplanted mature teeth in unmatched monkeys. The material comprised 40 mature maxillary central incisors in 20 green Vervet monkeys (Cercopithecus aethiops). Teeth were either allotransplanted or autotransplanted in pairs of monkeys matched only for the size of the root. Endodontic treatment was performed at random peroperatively with gutta percha and Kerr sealer in 10 of each of the 20 autografts and 20 allografts. The extra-alveolar period was 18 minutes in all groups. Histometric analysis, which included registration of surface and inflammatory and replacement resorption (ankylosis), was done on serial sections of the grafts 8 weeks after transplantation. Endodontic treatment almost completely reduced inflammatory resorption in both allotransplanted and autotransplanted mature teeth (p less than 0.01). Peroperative endodontics elicited a small increase in ankylosis in autografts. In allografts, it unmasked a high amount of ankylosis, presumably primarily due to alloimmune reactions against the donor periodontal ligament, leaving only a small portion of normal ligament almost exclusively located along the cervical region of the root surface. Downgrowth of periodontal pocket epithelium was limited in all groups.

Microleakage of four root canal sealer cements as determined by an electrochemical technique

Eighty-eight teeth were used to determine the sealing quality of four root canal sealer cements—Kerr, Diaket, AH-26, and ProcoSol—via the vertical condensation of warm gutta-percha technique. In addition, limited studies were carried out to determine the sealing quality of injected Hydron and thermoplasticized gutta-percha. A comparison was also made between the lateral condensation of gutta-percha and vertical condensation of warm gutta-percha when Kerr sealer was used. Teeth filled with vertical condensation of warm gutta-percha and AH-26 sealer cement showed lower leakage in one experiment but higher leakage in another. Hydron showed the highest leakage of any material. Teeth filled via vertical condensation of warm gutta-percha and Diaket showed less leakage than the other groups. A statistically significant difference was also found between lateral condensation of gutta-percha and vertical condensation of warm gutta-percha using Kerr sealer cement.

Antibody formation to dog pulp tissue altered by Kerr (Rickert's) sealer via the root canal.

Pulp tissue from three experimental dogs was tested for its antigenicity before and after incubation with Kerr (Rickert's) sealer (KS). Reactions to Arthus skin tests showed an increased response to pulp that had been incubated in KS, washed, and then injected, as compared with the material alone. Hemagglutinating antibody titers (1/360--1/600) were obtained from pulp tissue altered by KS. Inhibition tests showed the specificity of the antibody to be at a dilution of titer of 1:300. Therefore, a mixture of Kerr (Rickert's) sealer altered dog pulp tissue and rendered it antigenically active, and a specific humoral response was produced.

A study of long-term toxicity of endodontic materials with use of an in vitro model

The major purpose of this study was to determine the duration of the toxic effects of various root canal materials on bovine pulp cells grown in tissue culture. The test materials were mixed according to manufacturer's instructions, allowed to set, and ground to particle size of 50 to 100 μm. These particles were stored in sterile, normal saline solution at 37 C for one week, and 1, 3, or 5 months. Confluent bovine pulp cell mono layers in Falcon 30-ml T-flakes were seeded with low densities of material (<2 to 3 particles/mm2) from each storage-time interval. Areas of cellular death were measured at one through five days. Kerr antiseptic pulp canal sealer caused death of cells at early storage time intervals but ceased to do so by five months. N2, although initially more toxic, ceased to be more toxic by three months. RC-2B was equally as toxic as N2 and remained so at five months. Gutta-percha remained highly toxic throughout the test period. It is concluded that toxicity caused by water-soluble components is responsible for the N2 and RC-2B results, that the toxicity of Kerr's sealer probably decreases because of the final setting, and that gutta percha retains its toxicity because of minimally soluble components in the point. The major purpose of this study was to determine the duration of the toxic effects of various root canal materials on bovine pulp cells grown in tissue culture. The test materials were mixed according to manufacturer's instructions, allowed to set, and ground to particle size of 50 to 100 μm. These particles were stored in sterile, normal saline solution at 37 C for one week, and 1, 3, or 5 months. Confluent bovine pulp cell mono layers in Falcon 30-ml T-flakes were seeded with low densities of material (<2 to 3 particles/mm2) from each storage-time interval. Areas of cellular death were measured at one through five days. Kerr antiseptic pulp canal sealer caused death of cells at early storage time intervals but ceased to do so by five months. N2, although initially more toxic, ceased to be more toxic by three months. RC-2B was equally as toxic as N2 and remained so at five months. Gutta-percha remained highly toxic throughout the test period. It is concluded that toxicity caused by water-soluble components is responsible for the N2 and RC-2B results, that the toxicity of Kerr's sealer probably decreases because of the final setting, and that gutta percha retains its toxicity because of minimally soluble components in the point.

Cell-mediated immune response to dog pulp tissue altered by Kerr (Rickert's) sealer via the root canal

Pulp tissue from three experimental dogs was tested for its antigenicity before and after incubation with Kerr (Rickert's) sealer (KS). Cell-mediated skin test reactions showed an increased response to pulp that had been altered by KS and injected as compared with pulp or KS alone. In vitro analysis of cell-mediated immune response (lymphocyte proliferation) showed a distinct increase when pulp tissue was incubated in KS and washed as compared with pulp treated with saline solution. By comparing the saline-incubated with the KS-altered pulp, the increase in radioactivity was statistically significant at P < .0001. Therefore, KS altered dog pulp tissue and rendered it antigenically active, and produced a specific cell-mediated lymphocyte response.

Physical properties of root canal cements

AH26, Diaket, Kerr sealer, Mynol, N2, N2 no-lead, Procosol, Roth 801, Roth 811, RC2B, Tubliseal, and zinc oxide-eugenol cement were examined for particle size, flow, setting time, adhesion, and peripheral leakage. The results varied in a wide range. An examination of the data should help the generalist or the endodontist toward a better understanding of the material he is using, and should suggest to manufacturers opportunities for improving their products.

Sealing properties of endodontic filling materials using radioactive polar and nonpolar isotopes

A preliminary study was conducted on the sealing properties of root canal cements, using radioactive isotopes of different particle sizes and chemical polarity. A newly modified autoradiographic technique was used to interpret leakage patterns. Under the conditions used in this study, gross leakage patterns resulted when tooth specimens were filled only with central cores of either gutta-percha or silver cones without cement. A gradient of leakage patterns was observed when eight root canal cements were tested in conjunction with central cores of silver or gutta-percha. Of the eight root canal cements tested with radio-sulfur (S 35) and tritiated glucose, only Proco-Sol and AH-26 showed no leakage. Varied results were obtained when the root canal cements were tested with tritiated proline at pH 4.8 and pH 8.2 Kloroperka N-O, Diaket, Pulpdent's PCA, and Kerr sealer exhibited leakage by the method used in this study.

Toxicity of endodontic filling materials

Ten materials used as root canal sealers were evaluated experimentally. These materials were (1) zinc oxide and eugenol, (2) AH-26, (3) Diaket, (4) Proco-Sol radiopaque silver cement, (5) Proco-Sol nonstaining root canal cement, (6) Kerr sealer, (7) Kloroperka, (8) N 2, (9) N 2 Medical, and (10) Mynol root canal sealer. Four methods of testing were utilized, as follows: 1. A. Animal study, in which the subcutaneous connective tissue of the rat was observed for inflammatory response to implants of the materials tested. 2. B. Tissue-culture toxicity study in which varying dilutions of the test materials were placed on tissue cultures of HeLa cells and the degree of toxicity noted. 3. C. A bacteriologic study wherein the degree of growth inhibition of the test materials to known organisms was measured. 4. D. A selected-material animal study in which four of the test materials were placed in the conjunctival sac of the eye of the rabbit. This structure was then observed for degree of inflammation. The materials were found to be fairly consistent from study to study. Some variables were noted, but for the most part the materials exhibited a fairly uniform response within each test group when all methods were compared.

A comparative study of three root canal sealing agents

Three available root canal sealers were investigated and compared for tissue tolerance, antimicrobial activity, tensile strength, permeability, and clinical use. The Kerr sealer, the new Grossman sealer, and Diaket were tolerated equally well by the soft tissues of the rabbit. All three compounds possessed antimicrobial activity against the ten micro-organisms studied. The new Grossman sealer and Diaket were somewhat more active in this respect than the Kerr sealer. The Diaket was superior to the other sealers for its tensile strength and resistance to permeability. The Kerr sealer has stood the test of time, as far as clinical use is concerned. The other two compounds are equally well accepted by the human periapical tissues, however, and have other more desirable properties.