. Sterile polished slabs of bovine enamel, mounted in small acrylic cylinders, were held in the m... more . Sterile polished slabs of bovine enamel, mounted in small acrylic cylinders, were held in the mouth for 2 hours. The acquired pellicles deposited on the enamel surfaces were examined in situ on the slabs or after transfer to microscope slides. Indirect immunofluorescent staining in situ afforded positive identification of IgA and lysozyme in pellicles. The preferred technique required acid separation of the pellicle from the enamel, transfer to a microscope slide, and fixation in cold ethanol. Histochemically, this pellicle appeared to he predominantly basic. Results of indirect immunofluorescent tracing indicated that IgA and lysozyme were regular constituents of the pellicle, amylase and IgG were less consistently detected, and albumin and fibrinogen were rarely encountered.
Effects of therapeutic and pulp protecting dental materials on nervous tissue were studied in an ... more Effects of therapeutic and pulp protecting dental materials on nervous tissue were studied in an in vitro model utilizing the isolated left rat phrenic nerve. The nerve was placed in a buffer bath between two suction electrodes, one for electrical stimulation and one for recording. Evoked compound action potentials (cAP) were monitored in an oscilloscope. Fresh mixes of six commonly used pulp-dentin materials were placed in contact with the nerve, and the cAP registered. Formocresol, zinc oxide-eugenol (ZOE), Calasept and Dycal caused a complete depression of the nerve activity within 0.5 to 5 min of contact. The depression appeared irreversible with Formocresol and Calasept, reversible with Dycal, and reversible with ZOE when applied to nerves surrounded by adherent fatty tissue. De Trey Zinc and Durelon caused only a minor depression of the cAP within 30 min of contact.
The clinical performance of three endodontic sealers, AH 26®, Kloroperka N-0® and ProcoSol®, was ... more The clinical performance of three endodontic sealers, AH 26®, Kloroperka N-0® and ProcoSol®, was assessed in a prospective study of endodontic treatment in 810 roots. The roots were treated by undergraduate students according to a standardized procedure, and were filled with laterally condensed gutta-percha and sealer. The sealer was randomly selected just prior to filling. The patients were recalled yearly for 4 years for a clinical and radiographic control examination, and the radiographs were scored using the periapical index (PAI) scoring system. Ridit analysis provided optimal discrimination between subgroups of roots with regard to the radiographic status of the periapical tissues as a measure of the clinical performance of the materials. The periapical status of roots filled with AH 26® or ProcoSol® was better than that of roots filled with Kloroperka®. The difference was significant after 1 year and persisted through the 4-year observation period. The difference was also evident after stratification of the material with regard to preoperative pulpal and periapical diagnoses. It is concluded that the choice of sealer may infiuence the outcome of endodontic treatment, and that the perapical index is a useful discriminatory tool for assessment of treatment results in endodontics.
There are few studies on the prevalence of chronic apical periodontitis and endodontic treatment ... more There are few studies on the prevalence of chronic apical periodontitis and endodontic treatment in society. In this study, the periapical status of a representative sample of 35-yearolds in Oslo, Norway was studied by analyses of orthopantomograms and intraoral radiographs. The study also included quality assessment of root fillings and a correlation between quality and periapical status. Of the 3917 teeth evaluated, 133 (3.4%) were endodontically treated and 54 (1.4%) presented a periapical pathosis. More than half of these were associated with root-filled teeth. Endodontic treatment was considered successful with normal periapical structures in 64% of the cases. However, only 41% of the root fillings were of optimal quality, terminating 1-2 mm from the radiographic apex. Based on a survey of orthopantomograms, it was estimated that 30% of the subjects investigated presented an endodontic treatment need. The prevalence of endodontic treatment among 35-year-olds was unchanged from 1973 to 1984.
Test specimens of amalgam, gold, porcelain, heat-cured acrylic resin, and human enamel were made ... more Test specimens of amalgam, gold, porcelain, heat-cured acrylic resin, and human enamel were made to fit into cavities prepared in acrylic pontics of maxillary bridges. One side of the specimen was in close contact with the mucosa. Plaque was allowed to accumulate on the specimens for 27 to 48 days, and adherent bacteria were then quantified by cultivation on selective and non-selective media. The inflammatory status of the mucosa overlying the specimens were monitored by exudation measurements. Lower total numbers of bacteria were recovered from acrylic specimens than from the other materials used, including enamel. There were also significant subject differences in bacterial recovery. Test specimens in contact with inflamed mucosa yielded less total numbers of bacteria, but higher numbers of Streptococcus mutans, than did specimens exposed to mucosa with no or negligible exudation.
Four brands of endodontic paper points were subjected to tests for sterility, antibacterial activ... more Four brands of endodontic paper points were subjected to tests for sterility, antibacterial activity, and suitability as vehicles for bacteriological sampling procedures. No brand showed growth in the sterility assay. One brand showed weak but reproducible antibacterial activity. Recovery of viable bacteria after absorption into the points varied and appeared to depend both on the brand of point and on the bacterial strain used. One brand appeared ineffectual for clinical bacteriological sampling procedures.
NIOM-SCANDINAVIAN INSTITUTE OF DENTAL MATERIALS Root canals with vital pulps in four Macaca fasci... more NIOM-SCANDINAVIAN INSTITUTE OF DENTAL MATERIALS Root canals with vital pulps in four Macaca fascicularis monkeys were subjected to pulp extirpation and root filling with1 gutta-percha and sealer, either AH26, Endomethasone, Kloroperka N-G, or ProcoSol. Observation pleriods were 1 and 6 months. The results of treatment were evaluated by radiographic analysis (periapical index scores) and by histopathologic assessment of the remaining pulp and periapical tissues. Sixty roots with acceptable termination (between 0.5 and 3 mm from apex) of the root fillings and adequate histopathologic specimens were available for analysis. These roots were equally distributed in
One-hundred and twenty-three polyethylene tube implants of 12 endodontic sealers were placed subc... more One-hundred and twenty-three polyethylene tube implants of 12 endodontic sealers were placed subcutaneously into rats. The implants were left in situ for periods of 14 and 90 days. The tissue response was analyzed histologically and by scanning X-ray microanalysis. The tissue responses differed markedly in the intensity, extent, and cellular characterislics. A slight long-term tissue response was noted for polymeric resin-based materials; zinc oxide-eugenol-based sealers gave a stronger reaction; and a chloroform-based and two paste-type materials caused the least favorable reactions. X-ray microanalysis of tissue sections revealed material components in the reactive capsule and in the peripheral connective tissue of most specimens investigated. Implants of the resin-based sealers, AH26 and Hydron, were surrounded by macrophages, phagocytosing heavy metal components (Bi, Ba) of the materials. Zinc oxide-eugenol-and chloroform-based materials appeared more frequently to fragment into particles of sizes too large for monocellular phagocytosis.
In this study computerized image analysis procedures were applied to endodontic radiographs. Kont... more In this study computerized image analysis procedures were applied to endodontic radiographs. Kontron IBAS 2000 is a commercially available image analysis system with processing routines applicable to radiograph digitizing and transformations. The system was evaluated for: its ability to harmonize blackening and contrast in endodontie radiographs; its ability to compensate for angulation distortion of sequential exposures of individual teeth; its potential for applieation of digital subtraction methods; and its use in automated gray-level analyses of diseased and healthy bone areas in endodontic radiographs. The Kontron IBAS 2000 system proved suitable for all applieations. However, the speciflcity of the subtraction procedure was limited by some inherent problems in the harmonization of blackening and in the subtraction process itself. On the other hand, automated gray level measurements proved to be a robust method for unbiased and quantitative assessment of healing of apical periodontitis.
An in vitro model was developed for investigation of Candida albicans penetration into human dent... more An in vitro model was developed for investigation of Candida albicans penetration into human dentinal tubules. The model consisted of a dentin disc mounted between two cuvettes that each had a circular opening facing the disc. The cuvettes were filled with Tryptic-Soy-Broth, and the pulpal side cuvette was inoculated with C. albicans and incubated at 37 degrees C in air until growth occurred in the uninoculated cuvette or up to 30 days. The system was also used with Enterococcus faecalis. Completely glue-covered dentin specimens served as negative controls. Brown & Brenn-stained histological preparations of the specimens were examined with light microscopy. The time needed before growth occurred in the uninoculated cuvette showed great variation with C. albicans, whereas E. faecalis penetrated within 1 to 5 days of incubation. Slight penetration both by hyphae and yeast cells was observed in specimens inoculated with C. albicans, whereas specimens inoculated with E. faecalis showed ...
Acta pathologica et microbiologica Scandinavica. Section B, Microbiology, 1977
Macromolecular solutes (albumin, concanavalin A, whole saliva, serum) caused impaired sorption of... more Macromolecular solutes (albumin, concanavalin A, whole saliva, serum) caused impaired sorption of Streptococcus faecium and Streptococcus sanguis to glass. The inhibitory effect resided chiefly with interactions of the solutes with the glass surface. In the case of sorption of S. sanguis to glass in the presence of parotid fluid, the inhibitory effect was counteracted by a specific attachment of S. sanguis cells mediated by some component(s) of the parotid fluid. Agglutination of the test organisms was in general accompanied by inhibition of sorption. However, when small or unstable aggregates were formed, the number of cells adhering on the glass surface was increased. The findings are discussed with reference to the colonization of teeth by oral bacteria.
The antibacterial activity of dental restorative materials (12 resin based and one silicate) was ... more The antibacterial activity of dental restorative materials (12 resin based and one silicate) was tested in vitro against 5 species of bacteria. When fresh, all materials inhibited growth in pour plates of at least one bacterial strain. After storage in saline for 24 hours, the antibacterial activity was markedly reduced. There was a wide variation among the materials in the extent of their antibacterial activity. The bacterial strains apparently differed in their susceptibility to the antibacterial activity of the materials.
. Sterile polished slabs of bovine enamel, mounted in small acrylic cylinders, were held in the m... more . Sterile polished slabs of bovine enamel, mounted in small acrylic cylinders, were held in the mouth for 2 hours. The acquired pellicles deposited on the enamel surfaces were examined in situ on the slabs or after transfer to microscope slides. Indirect immunofluorescent staining in situ afforded positive identification of IgA and lysozyme in pellicles. The preferred technique required acid separation of the pellicle from the enamel, transfer to a microscope slide, and fixation in cold ethanol. Histochemically, this pellicle appeared to he predominantly basic. Results of indirect immunofluorescent tracing indicated that IgA and lysozyme were regular constituents of the pellicle, amylase and IgG were less consistently detected, and albumin and fibrinogen were rarely encountered.
Effects of therapeutic and pulp protecting dental materials on nervous tissue were studied in an ... more Effects of therapeutic and pulp protecting dental materials on nervous tissue were studied in an in vitro model utilizing the isolated left rat phrenic nerve. The nerve was placed in a buffer bath between two suction electrodes, one for electrical stimulation and one for recording. Evoked compound action potentials (cAP) were monitored in an oscilloscope. Fresh mixes of six commonly used pulp-dentin materials were placed in contact with the nerve, and the cAP registered. Formocresol, zinc oxide-eugenol (ZOE), Calasept and Dycal caused a complete depression of the nerve activity within 0.5 to 5 min of contact. The depression appeared irreversible with Formocresol and Calasept, reversible with Dycal, and reversible with ZOE when applied to nerves surrounded by adherent fatty tissue. De Trey Zinc and Durelon caused only a minor depression of the cAP within 30 min of contact.
The clinical performance of three endodontic sealers, AH 26®, Kloroperka N-0® and ProcoSol®, was ... more The clinical performance of three endodontic sealers, AH 26®, Kloroperka N-0® and ProcoSol®, was assessed in a prospective study of endodontic treatment in 810 roots. The roots were treated by undergraduate students according to a standardized procedure, and were filled with laterally condensed gutta-percha and sealer. The sealer was randomly selected just prior to filling. The patients were recalled yearly for 4 years for a clinical and radiographic control examination, and the radiographs were scored using the periapical index (PAI) scoring system. Ridit analysis provided optimal discrimination between subgroups of roots with regard to the radiographic status of the periapical tissues as a measure of the clinical performance of the materials. The periapical status of roots filled with AH 26® or ProcoSol® was better than that of roots filled with Kloroperka®. The difference was significant after 1 year and persisted through the 4-year observation period. The difference was also evident after stratification of the material with regard to preoperative pulpal and periapical diagnoses. It is concluded that the choice of sealer may infiuence the outcome of endodontic treatment, and that the perapical index is a useful discriminatory tool for assessment of treatment results in endodontics.
There are few studies on the prevalence of chronic apical periodontitis and endodontic treatment ... more There are few studies on the prevalence of chronic apical periodontitis and endodontic treatment in society. In this study, the periapical status of a representative sample of 35-yearolds in Oslo, Norway was studied by analyses of orthopantomograms and intraoral radiographs. The study also included quality assessment of root fillings and a correlation between quality and periapical status. Of the 3917 teeth evaluated, 133 (3.4%) were endodontically treated and 54 (1.4%) presented a periapical pathosis. More than half of these were associated with root-filled teeth. Endodontic treatment was considered successful with normal periapical structures in 64% of the cases. However, only 41% of the root fillings were of optimal quality, terminating 1-2 mm from the radiographic apex. Based on a survey of orthopantomograms, it was estimated that 30% of the subjects investigated presented an endodontic treatment need. The prevalence of endodontic treatment among 35-year-olds was unchanged from 1973 to 1984.
Test specimens of amalgam, gold, porcelain, heat-cured acrylic resin, and human enamel were made ... more Test specimens of amalgam, gold, porcelain, heat-cured acrylic resin, and human enamel were made to fit into cavities prepared in acrylic pontics of maxillary bridges. One side of the specimen was in close contact with the mucosa. Plaque was allowed to accumulate on the specimens for 27 to 48 days, and adherent bacteria were then quantified by cultivation on selective and non-selective media. The inflammatory status of the mucosa overlying the specimens were monitored by exudation measurements. Lower total numbers of bacteria were recovered from acrylic specimens than from the other materials used, including enamel. There were also significant subject differences in bacterial recovery. Test specimens in contact with inflamed mucosa yielded less total numbers of bacteria, but higher numbers of Streptococcus mutans, than did specimens exposed to mucosa with no or negligible exudation.
Four brands of endodontic paper points were subjected to tests for sterility, antibacterial activ... more Four brands of endodontic paper points were subjected to tests for sterility, antibacterial activity, and suitability as vehicles for bacteriological sampling procedures. No brand showed growth in the sterility assay. One brand showed weak but reproducible antibacterial activity. Recovery of viable bacteria after absorption into the points varied and appeared to depend both on the brand of point and on the bacterial strain used. One brand appeared ineffectual for clinical bacteriological sampling procedures.
NIOM-SCANDINAVIAN INSTITUTE OF DENTAL MATERIALS Root canals with vital pulps in four Macaca fasci... more NIOM-SCANDINAVIAN INSTITUTE OF DENTAL MATERIALS Root canals with vital pulps in four Macaca fascicularis monkeys were subjected to pulp extirpation and root filling with1 gutta-percha and sealer, either AH26, Endomethasone, Kloroperka N-G, or ProcoSol. Observation pleriods were 1 and 6 months. The results of treatment were evaluated by radiographic analysis (periapical index scores) and by histopathologic assessment of the remaining pulp and periapical tissues. Sixty roots with acceptable termination (between 0.5 and 3 mm from apex) of the root fillings and adequate histopathologic specimens were available for analysis. These roots were equally distributed in
One-hundred and twenty-three polyethylene tube implants of 12 endodontic sealers were placed subc... more One-hundred and twenty-three polyethylene tube implants of 12 endodontic sealers were placed subcutaneously into rats. The implants were left in situ for periods of 14 and 90 days. The tissue response was analyzed histologically and by scanning X-ray microanalysis. The tissue responses differed markedly in the intensity, extent, and cellular characterislics. A slight long-term tissue response was noted for polymeric resin-based materials; zinc oxide-eugenol-based sealers gave a stronger reaction; and a chloroform-based and two paste-type materials caused the least favorable reactions. X-ray microanalysis of tissue sections revealed material components in the reactive capsule and in the peripheral connective tissue of most specimens investigated. Implants of the resin-based sealers, AH26 and Hydron, were surrounded by macrophages, phagocytosing heavy metal components (Bi, Ba) of the materials. Zinc oxide-eugenol-and chloroform-based materials appeared more frequently to fragment into particles of sizes too large for monocellular phagocytosis.
In this study computerized image analysis procedures were applied to endodontic radiographs. Kont... more In this study computerized image analysis procedures were applied to endodontic radiographs. Kontron IBAS 2000 is a commercially available image analysis system with processing routines applicable to radiograph digitizing and transformations. The system was evaluated for: its ability to harmonize blackening and contrast in endodontie radiographs; its ability to compensate for angulation distortion of sequential exposures of individual teeth; its potential for applieation of digital subtraction methods; and its use in automated gray-level analyses of diseased and healthy bone areas in endodontic radiographs. The Kontron IBAS 2000 system proved suitable for all applieations. However, the speciflcity of the subtraction procedure was limited by some inherent problems in the harmonization of blackening and in the subtraction process itself. On the other hand, automated gray level measurements proved to be a robust method for unbiased and quantitative assessment of healing of apical periodontitis.
An in vitro model was developed for investigation of Candida albicans penetration into human dent... more An in vitro model was developed for investigation of Candida albicans penetration into human dentinal tubules. The model consisted of a dentin disc mounted between two cuvettes that each had a circular opening facing the disc. The cuvettes were filled with Tryptic-Soy-Broth, and the pulpal side cuvette was inoculated with C. albicans and incubated at 37 degrees C in air until growth occurred in the uninoculated cuvette or up to 30 days. The system was also used with Enterococcus faecalis. Completely glue-covered dentin specimens served as negative controls. Brown & Brenn-stained histological preparations of the specimens were examined with light microscopy. The time needed before growth occurred in the uninoculated cuvette showed great variation with C. albicans, whereas E. faecalis penetrated within 1 to 5 days of incubation. Slight penetration both by hyphae and yeast cells was observed in specimens inoculated with C. albicans, whereas specimens inoculated with E. faecalis showed ...
Acta pathologica et microbiologica Scandinavica. Section B, Microbiology, 1977
Macromolecular solutes (albumin, concanavalin A, whole saliva, serum) caused impaired sorption of... more Macromolecular solutes (albumin, concanavalin A, whole saliva, serum) caused impaired sorption of Streptococcus faecium and Streptococcus sanguis to glass. The inhibitory effect resided chiefly with interactions of the solutes with the glass surface. In the case of sorption of S. sanguis to glass in the presence of parotid fluid, the inhibitory effect was counteracted by a specific attachment of S. sanguis cells mediated by some component(s) of the parotid fluid. Agglutination of the test organisms was in general accompanied by inhibition of sorption. However, when small or unstable aggregates were formed, the number of cells adhering on the glass surface was increased. The findings are discussed with reference to the colonization of teeth by oral bacteria.
The antibacterial activity of dental restorative materials (12 resin based and one silicate) was ... more The antibacterial activity of dental restorative materials (12 resin based and one silicate) was tested in vitro against 5 species of bacteria. When fresh, all materials inhibited growth in pour plates of at least one bacterial strain. After storage in saline for 24 hours, the antibacterial activity was markedly reduced. There was a wide variation among the materials in the extent of their antibacterial activity. The bacterial strains apparently differed in their susceptibility to the antibacterial activity of the materials.
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