Papers by Göran Sundqvist
It has recently been proposed that three asaccharolytic species forming pigmented colonies on blo... more It has recently been proposed that three asaccharolytic species forming pigmented colonies on blood agar should be transferred from the genus Bacteruides to the new genus Purphyrumunas. In the taxonomy of the genus Bacteruides cellular fatty acid profiles obtained by gas chromatography and mass spectrometry after methylation and derivatization of whole cells have proved to be useful. In this study
Oral surgery, oral medicine, and oral pathology, 1980
Five different methods of transport and cultivation of bacteria from dental root canal specimens ... more Five different methods of transport and cultivation of bacteria from dental root canal specimens were evaluated. Bacteria were recovered from 29 percent of the specimens when they were transported in VMG IV and subcultured in PRAS medium or on the surface of blood agar in an anaerobic box. When a PRAS-peptone-yeast extract broth was used for transport and the specimens were initially subcultured in the broth, bacteria were recovered from 49 percent of the specimens. When fluid thioglycollate medium USP (BBL) and Clausen medium (Oxoid) were used for transport as well as for initial subculture, bacteria were recovered from 58 percent and 47 percent of the specimens, respectively. The high recovery of bacteria by these media could to a significant degree be ascribed to the use of the media for initial subculture of the specimens. Recovery of bacteria by fluid thioglycollate medium USP was as good or even better as with the more elaborate PRAS medium. Fluid thioglycollate medium USP in ...
Oral Microbiology and Immunology, 1992
The existence of commensal or antagonistic relationships between microorganisms in the root canal... more The existence of commensal or antagonistic relationships between microorganisms in the root canals of teeth with apical periodontitis was investigated. Samples were taken from 65 infected human root canals and were analysed according to species, frequency of occurrence and proportion of the total isolated flora. The most frequent species were Fusobacterium nucleatum, Prevotella intermedia, Peptostreptococcus micros, Peptostreptococcus anaerobius, Eubacterium alactolyticum, Eubacterium lentum and Wolinella recta. An odds ratio system was used to calculate positive or negative associations between the isolated bacteria. Strong positive associations were found between F. nucleatum and P. micros, Porphyromonas endodontalis, Selenomonas sputigena and W. recta. There was also a positive association between P. intermedia and P. micros, P. anaerobius and the eubacteria. In general, species of streptococci, Propionibacterium propionica, Capnocytophaga ochracea and Veillonella parvula showed no or negative associations with the other bacteria. The results are consistent with the concept of a special and selective environment occurring in the root canal that is due, in part, to the cooperative as well as antagonistic nature of the relationships between bacteria in the root canal.
Journal of Medical Microbiology, 1984
Strains of six black-pigmented Bacteroides species and one un-named strain were examined for thei... more Strains of six black-pigmented Bacteroides species and one un-named strain were examined for their ability to degrade the plasma proteins albumin, haemopexin, haptoglobin and transferrin. Strains of B. gingivalis were most effective, degrading all four plasma proteins at different rates. Strains of B. intermedius and B. asaccharolyticus showed intermediate activities, degrading different individual plasma proteins; strains of B. melaninogenicus, B. loeschei and B. denticola were least active, degrading only haemopexin. These findings are discussed in relation to the availability in tissue fluids of iron for bacterial growth.
FEMS Immunology & Medical Microbiology, 1993
Journal of Endodontics, 1990
Light and electron microscopy were used to analyze nine therapy-resistant and asymptomatic human ... more Light and electron microscopy were used to analyze nine therapy-resistant and asymptomatic human periapical lesions, which were removed as block biopsies during surgical treatment of the affected teeth. The cases that required surgery represented about 10% of all of the cases which received endodontic treatment and root fillings during the period 1977 to 1984. These cases revealed periapical lesions when they were examined 4 to 10 yr after treatment. The biopsies were processed for correlated light and electron microscopy. Six of the nine biopsies revealed the presence of microorganisms in the apical root canal. Four contained one or more species of bacteria and two revealed yeasts. Of the four cases in which bacteria were found, only in one biopsy could they be found by light microscope. In the other three specimens, the bacterial presence could be confirmed only after repeated electron microscopic examination of the apical root canal by serial step-cutting technique. Among the three cases in which no microorganisms could be encountered, one showed histopathological features of a foreign body giant cell granuloma. These findings suggest that in the majority of root-filled human teeth with therapy-resistant periapical lesions, microorganisms may persist and may play a significant role in endodontic treatment failures. In certain instances such lesions may also be sustained by foreign body giant cell type of tissue responses at the periapex of root-filled teeth.
Journal of Endodontics, 1990
Although the primary etiological factor of periapical lesions is microbial, there are other indep... more Although the primary etiological factor of periapical lesions is microbial, there are other independent factors that can adversely affect the outcome of endodontic treatment. In this communication, we present morphological evidence in support of the role of a foreign body reaction of periapical tissue to root-filling materials. The specimen consisted of a surgical biopsy of an asymptomatic periapical lesion which persisted after a decade of postendodontic follow-up. The biopsy was processed for correlated light and electron microscopy and was analyzed by various microtechniques. The unique feature of the lesion was the presence of vast numbers of large multinucleated cells and their cytoplasmic inclusion bodies. Morphologically, these multinucleated cells resembled foreign body giant cells. They contained characteristic birefringent cytoplasmic inclusions which on electron-probe X-ray microanalysis consistently revealed the presence of magnesium and silicon. The magnesium and silicon are presumably the remnants of a root-filling excess which protruded into the periapex and had been resorbed during the follow-up period. These observations strongly suggest that in the absence of microbial factors, root-filling materials which contain irritating substances can evoke a foreign body reaction at the periapex, leading to the development of asymptomatic periapical lesions that may remain refractory to endodontic therapy for long periods of time.
Oral Surgery, Oral Medicine, Oral Pathology, 1987
The antibacterial effect of ultrasonic instrumentation in the treatment of infected root canals w... more The antibacterial effect of ultrasonic instrumentation in the treatment of infected root canals was clinically evaluated. Sodium hypochlorite solution (0.5%) was used as an irrigant, but no antibacterial intracanal dressing was used between the appointments. The ultrasonic technique eliminated the bacteria from the canals more efficiently than hand instrumentation alone. Even though ultrasonication definitely improves the procedure of root canal disinfection, the use of an antibacterial dressing between appointments is necessary to achieve as complete a reduction in bacterial levels as possible.
Journal of Endodontics, 1990
The influence of various factors that may affect the outcome of root canal therapy was evaluated ... more The influence of various factors that may affect the outcome of root canal therapy was evaluated in 356 patients 8 to 10 yr after the treatment. The results of treatment were directly dependent on the preoperative status of the pulp and periapical tissues. The rate of success for cases with vital or nonvital pulps but having no periapical radiolucency exceeded 96%, whereas only 86% of the cases with pulp necrosis and periapical radiolucency showed apical healing. The possibility of instrumenting the root canal to its full length and the level of root filling significantly affected the outcome of treatment. Of all of the periapical lesions present on previously root-filled teeth, only 62% healed after retreatment. The predictability from clinical and radiographic signs of the treatment-outcome in individual cases with preoperative periapical lesions cases was found to be low. Thus, factors which were not measured or identified may be critical to the outcome of endodontic treatment. Vol. 16, No. 10, October 1990 204 revealed apical radiolucency. In roots with pulp necrosis but no apical periodontitis, the necrosis was usually restricted to the coronal part of the canal. Of the 267 roots which had been filled earlier, 94 were retreated for the presence of
Journal of Endodontics, 2007
The fate of DNA from bacteria that infect the root canal but cannot survive is currently unknown,... more The fate of DNA from bacteria that infect the root canal but cannot survive is currently unknown, yet such information is essential in establishing the validity of polymerase chain reaction (PCR)-based identification methods for root canal samples. This in vitro study tested the hypothesis that PCR-detectable DNA from dead bacteria might persist after cell death and investigated the efficiency of sodium hypochlorite (NaOCl) as a field decontamination agent. Using heat-killed Enterococcus faecalis, the persistence of DNA encoding the 16S rRNA gene was monitored by PCR. While most probable number analysis showed an approximate 1000-fold decay in amplifiable template, E. faecalis DNA was still PCR-detectable 1 year after cell death. NaOCl (1%) eliminated amplifiable DNA within 60 seconds of exposure. Our findings also disclosed a previously overlooked problem of concentration-dependent inhibition of the PCR reaction by thiosulfate-inactivated NaOCl. These results highlight the challenges of reliably identifying the authentic living root canal flora with PCR techniques.
Research in Microbiology, 1999
Genomic fingerprints from the DNA of 27 strains of Porphyromonas endodontalis from diverse clinic... more Genomic fingerprints from the DNA of 27 strains of Porphyromonas endodontalis from diverse clinical and geographic origins were generated as random amplified polymorphic DNA (RAPD) using the technique of PCR amplification with a single primer of arbitrary sequence. Cluster analysis of the combined RAPD data obtained with three selected 9- or 10-mer-long primers identified 25 distinct RAPD types which clustered as three main groups identifying three genogroups. Genogroups I and II included exclusively P. endodontalis isolates of oral origin, while 7/9 human intestinal strains of genogroup III which linked at a similarity level of 52% constituted the most homogeneous group in our study. Genotypic diversity within P. endodontalis, as shown by RAPD analysis, suggests that the taxon is composed of two oral genogroups and one intestinal genogroup. This hypothesis remains to be confirmed.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2001
Objective. This report describes 2 endodontic patients who had persistent signs and symptoms afte... more Objective. This report describes 2 endodontic patients who had persistent signs and symptoms after conventional root canal treatment. The aim of this study was to determine what microorganisms were present in the root canals of the teeth with failed endodontic therapy.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 1999
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2008
To investigate the ability of Actinomyces radicidentis to survive and establish in soft connectiv... more To investigate the ability of Actinomyces radicidentis to survive and establish in soft connective tissue that grew into subcutaneously implanted tissue cages in Sprague-Dawley rats. Known concentrations of A. radicidentis suspension, grown on blood agar and broth cultures, were inoculated into tissue cages in rats. The cage contents were retrieved after 7, 14, and 28 days for culturing and correlative light and transmission electron microscopy. Cell suspensions harvested from both types of cultures showed substantial decline in numbers in tissue cages during the observation period. However, correlative light and transmission electron microscopy revealed numerous aggregates of coccoid bacteria already by 7 days of observation compared with the formation of well established colonies with characteristic actinomycotic features by 14 days after inoculation. These results suggest that the pathogenicity of A. radicidentis is due to its ability to form large aggregates of cells held together by embedding themselves in an extracellular matrix in vital host tissues. Thus, A. radicidentis, like other pathogenic Actinomyces, existing in the protected biofilm-environment can collectively evade destruction and elimination by host defenses, including phagocytosis.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2008
Objective. The objective of this study was to experimentally induce inflammatory cysts in an anim... more Objective. The objective of this study was to experimentally induce inflammatory cysts in an animal model so as to test the hypothesis that radicular cysts develop via the "abscess pathway." Methodology. Twenty-eight perforated custom-made Teflon cages were surgically implanted into defined locations in the back of 7 Sprague Dawley rats. A week after the implantation of the cages, a known quantity of freshly grown, close allogeneic oral keratinocytes in phosphate buffer solution (PBS) was injected into each cage. One cage per animal was treated as the control that received only epithelial cells. The remaining 3 cages of each animal were trials. Seven days post epithelial cell inoculation; a suspension of 0.2 mL of Fusobacterium nucleatum (10 8 bacteria per mL) was injected into each of the 3 trial cages. Two, 12, and 24 weeks after the inoculation of the bacteria, the cages were taken out, and the tissue contents were fixed and processed by correlative light and transmission electron microscopy. Sixteen of the 21 trial cages could be processed and yielded results. Results. Inoculations of epithelial cells followed 1 week later by F. nucleatum into tissue cages resulted in the development inflammatory cysts in 2 of the 16 cages. The 2 cages contained a total of 4 cystic sites. None of the control cages showed the presence of any cyst-like pathology. Conclusions. Inflammatory cysts were induced by initiating acute inflammatory foci (abscess/necrotic area) by bacterial injection that got enclosed by a proliferating epithelium. This finding provides strong experimental evidence in support of the "abscess theory" of development of radicular cysts.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2009
The microbiota inhabiting the untreated root canal differ markedly from those found in post-treat... more The microbiota inhabiting the untreated root canal differ markedly from those found in post-treatment disease, yet there is limited information on the microbial characteristics distinguishing the different infections. We hypothesized that starvation survival is a key microbial property in species selection. This study analyzed starvationsurvival behavior over 60 days of species representative of the untreated root canal infection: Fusobacterium nucleatum, Peptostreptococcus anaerobius, Prevotella intermedia and Pseudoramibacter alactolyticus. All species did not survive 1 day in water. In 1% serum, the 4 species could not survive beyond 2-3 weeks. They required a high initial cell density and Ն10% serum to survive the observation period. The results highlight a poor starvation-survival capacity of these 4 species compared with species prevalent in post-treatment infection, which are well equipped to endure starvation and survive in low numbers on minimal serum. These findings point to starvation-survival capacity as a selection factor for microbial participation in post-treatment disease.
Oral Microbiology and Immunology, 1992
Strains of Actitiomyces israelii and Arachnia propionica, isolated from clinical cases of failed ... more Strains of Actitiomyces israelii and Arachnia propionica, isolated from clinical cases of failed endodontic therapy, were examined for: (i) their ability to survive and establish themselves in the soft connective tissue that grew into subcutaneously implanted tissue cages in guinea pigs; (ii) cell-surface hydrophobicity; and (iii) phagocytosis and killing by human polymorphonuclear leukocytes (PMNs) under aerobic and anaerobic conditions. Bacteria were inoculated into the tissue cages in guinea pigs and the cage contents were retrieved after 1, 7, 14 and 21 d for culturing and light and electron microscopy. Both bacterial species showed substantial decline in the number of bacteria by day 7 after the inoculation. Thereafter, the A. israelii strain recovered and, by day 21, had started to increase in number. Light and electron microscopy revealed the formation of typical actinomycotic colonies. A. propionica, on the other hand, continued to decline in number during the entire period of experimental infection and did not form colonies. Both strains were hydrophobic, readily phagocytosed and were efficiently killed by hutnan PMNs under aerobic and anaerobic conditions in vitro. These results suggest that the pathogenicity of A. israelii is due to its ability to establish characteristic cohesive colonies consisting of branching filamentous organisms that are entneshed in an extracellular matrix. It seems that the organisms existing in such colonies can collectively evade destruction and elimination by host phagocytic cells, whereas in vitro suspensions of the bacteria are easily phagocytosed and efficiently killed by PMNs. With respect to A. propionica, further investigations are necessary to understand its pathogenicity.
Oral Microbiology and Immunology, 1998
Oral Microbiology and Immunology, 1988
The ability of Bacteroides gingivalis to generate chemotactic activity and the complement fragmen... more The ability of Bacteroides gingivalis to generate chemotactic activity and the complement fragment C5a in human serum was assayed. When fresh serum was incubated with B. gingivalis there was a rapid increase of chemotactic activity of the serum during the first 15 ...
Journal of Periodontal Research, 1987
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Papers by Göran Sundqvist