Biomedical subjects

A Molander

Publications and source records attributed to A Molander.

16 recordsLinked to original sources

PubMed2006

Diagnostic value of computed tomography in re-treatment of root fillings in maxillary molars.

AIM: To compare the diagnostic information and radiation dose between intraoral radiography and computed tomography (CT) in re-treatment decision making concerning root fillings in maxillary molars. METHODOLOGY: Thirty-nine root-filled maxillary molars with suspected apical periodontitis were examined with two intraoral periapical radiographs and CT. Presence of periapical lesion/s per tooth and root were analysed for both techniques. In addition, in the CT images, the number of root canals, erosion, or perforation of cortical bone plates, and the distance between palatal root and cortical bone plates were evaluated. Radiation dose for CT was registered and calculated; and that of periapical radiographs used as reported previously (Ekestubbe et al. 2004). RESULTS: Periapical radiographs revealed periapical lesions in 33 teeth compared with 38 on CT images. A lesion of any root was detected more often with CT. The mesiobuccal root had two root canals in 30 teeth of which 27 of the MB2 canals were not filled, and 22 roots with an unfilled canal were associated a periapical lesion. Distances to palatal root, from the buccal and palatal cortex were measured in CT and varied between 5.0-12.0 mm and 0-4.0 mm, respectively. Based on the radiographic information, a variety of treatment alternatives were suggested. Mean effective dose of periapical radiographs was 0.02 mSv and that of CT 0.055 mSv. CONCLUSIONS: Computed tomography may give important information in re-treatment decision when considering root fillings in maxillary molars. The radiation dose should be considered individually.

Adult↗

PubMed2005

Virulence, phenotype and genotype characteristics of endodontic Enterococcus spp.

BACKGROUND/AIMS: Enterococci have been implicated in persistent root canal infections but their role in the infection process remains unclear. This study investigated the virulence, phenotype and genotype of 33 endodontic enterococcal isolates. METHODS: Phenotypic tests were conducted for antibiotic resistance, clumping response to pheromone, and production of gelatinase, hemolysin and bacteriocin. Genotype analysis involved polymerase chain reaction amplification of virulence determinants encoding aggregation substances asa and asa373, cytolysin activator cylA, gelatinase gelE, gelatinase-negative phenotype ef1841/fsrC, adherence factors esp and ace, and endocarditis antigen efaA. Physical DNA characterization involved pulsed-field gel electrophoresis of genomic DNA, and plasmid analysis. RESULTS: Potential virulence traits expressed included production of gelatinase by Enterococcus faecalis (n=23), and response to pheromones in E. faecalis culture filtrate (n=16). Fourteen strains produced bacteriocin. Five strains were resistant to tetracycline and one to gentamicin, whereas all were susceptible to ampicillin, benzylpenicillin, chloramphenicol, erythromycin, fusidic acid, kanamycin, rifampin, streptomycin and vancomycin. Polymerase chain reaction products encoding efaA, ace, and asa were detected in all isolates; esp was detected in 20 isolates, cylA in six isolates, but asa373 was never detected. The gelatinase gene (gelE) was detected in all isolates of E. faecalis (n=31) but not in Enterococcus faecium (n=2); a 23.9 kb deletion sequence corresponding to the gelatinase-negative phenotype was detected in six of the eight E. faecalis isolates that did not produce gelatinase. Pulsed-field gel electrophoresis and plasmid analyses revealed genetic polymorphism with clonal types evident. Plasmid DNA was detected in 25 strains, with up to four plasmids per strain and a similar (5.1 kb) plasmid occurring in 16 isolates. CONCLUSIONS: Phenotypic and genotypic evidence of potential virulence factors were identified in endodontic Enterococcus spp., specifically production of gelatinase and response to pheromones.

Adult↗

PubMed2004

Quantitative real-time PCR detection of oral Enterococcus faecalis in humans.

OBJECTIVE: Enterococcus faecalis is consistently associated with recurrent root canal infections. Only low concentrations of E. faecalis in the human mouth have been demonstrated by culture techniques. Quantitative detection strategies more sensitive than culturing, such as quantitative PCR (qPCR), could provide more illuminating data. DESIGN: Thirty outpatients attending the University of Michigan Graduate Endodontic Clinic for endodontic treatment provided oral rinse samples that were analysed for E. faecalis using qPCR and microbiological culturing. A SYBR Green I qPCR protocol was developed for the quantifiable detection of E. faecalis and total bacteria in oral rinse samples using primers designed to target the 16S rRNA gene. Annealing temperature and primer, magnesium ion, and dimethyl sulfoxide concentrations were investigated for optimisation of the protocol; a minimum sensitivity limit of 23 rRNA copies (an estimated six E. faecalis cells) was established for E. faecalis in pure culture, and 104 rRNA copies (an estimated 26 E. faecalis cells) in mixed culture. RESULTS: In qPCR assays, based on extrapolation from estimated rRNA gene copy numbers, E. faecalis comprised 0.0006-0.0047% of a total bacteria load that ranged from 5.92 x 10(5) to 5.69 x 10(7) cells/ml of oral rinse. E. faecalis was detected in five (17%) samples in concentrations from 114 to 490 cells/ml. In parallel culture assays E. faecalis were detected in only two samples (7%) of the five identified by qPCR and in concentrations 30 and 240 CFU/ml. CONCLUSIONS: qPCR reported a higher incidence of E. faecalis in oral rinse samples than culture techniques and afforded greater sensitivity.

Colony-Forming Units Assay↗

PubMed2004

Microbiological evaluation of one- and two-visit endodontic treatment of teeth with apical periodontitis: a randomized, clinical trial.

The antimicrobial efficacy of endodontic procedures performed in one-visit (including a 10-min intraappointment dressing with 5% iodine-potassium-iodide) was compared with a two-visit procedure (including an interappointment dressing with calcium-hydroxide paste). Teeth with apical periodontitis (n = 96) were randomly assigned to either group. Root canal sampling and culturing were performed before and immediately after instrumentation, and after medication. Initial sampling demonstrated the presence of microorganisms in 98% of the teeth. Postinstrumentation sampling showed reduction of cultivable microbiota. Antibacterial dressing further reduced the number of teeth with surviving microbes. In the postmedication samples, residual microorganisms were recovered in 29% of the one-visit teeth and in 36% of the two-visit treated teeth. No statistically significant differences between the groups were discerned. It was concluded that from a microbiological point of view, treatment of teeth with apical periodontitis performed in two appointments was not more effective than the investigated one-visit procedure.

Bacteria, Anaerobic↗

PubMed2004

Gram-positive rods prevailing in teeth with apical periodontitis undergoing root canal treatment.

AIMS: To identify Gram-positive rods from root canals of teeth with apical periodontitis and to examine their associations with other species. METHODOLOGY: Consecutive root canal samples (RCSs) from 139 teeth undergoing root canal treatment were analyzed prospectively for cultivable microbes. Gram-positive rods in the first RCS submitted after chemo-mechanical preparation were categorised to genus level by selective media and gas-liquid chromatography (GLC), and identified to species level by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Associations between organisms were measured by odds ratios (OR). RESULTS: In the first samples submitted a total of 158 Gram-positive rods, 115 Gram-positive cocci, 26 Gram-negative rods and 9 Gram-negative cocci, were identified. At genus levels Gram-positive rods were classified into: Lactobacillus spp. (38%), Olsenella spp. (18%), Propionibacterium spp. (13%), Actinomyces spp. (12%), Bifidobacterium spp. (13%) and Eubacterium spp. (6%). The most frequent species were Olsenella uli, Lactobacillus paracasei and Propionibacterium propionicum. In subsequent samples taken during treatment, Gram-positive rods were also identified, although the number of strains was considerably reduced. Positive associations were observed between members of the genus lactobacilli and Gram-positive cocci (OR>2). CONCLUSIONS: Olsenella uli and Lactobacillus spp. predominated over other Gram-positive rods. A possible association exists between Lactobacillus spp. and Gram-positive cocci in root canals of teeth with apical periodontitis receiving treatment.

Adolescent↗

PubMed2003

Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment.

UNLABELLED: Chávez de Paz LE, Dahlén G, Molander A, Möller A, Bergenholtz G. Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment. International Endodontic Journal, 36, 500-508, 2003. AIM: To determine whether there is a pattern for certain bacteria to remain after chemo-mechanical treatment of root canals in teeth with apical periodontitis. METHODOLOGY: Consecutive root-canal samples of 200 teeth receiving root-canal treatment, referred from general practitioners and endodontic specialists for analyses of cultivable microbes, were studied prospectively. To be included, samples had to be taken at a treatment session subsequent to the one at which endodontic therapy was initiated. All samples were from teeth that either presented with clinical or radiographic evidence of apical periodontitis or both. Bacteriological findings were linked to clinical and radiographic parameters including status of the root canal prior to treatment, namely, vital pulp, necrotic pulp or root filled. RESULTS: A total of 248 strains were isolated from 107 teeth giving bacterial growth. Gram-positives predominated (85%). Lactobacillus spp. (22%), nonmutans streptococci (18%), and Enterococcus spp. (12%) were the most common isolates. Gram-negative anaerobes were relatively sporadic. Large radiographic bone lesions, persistent pain and use of intracanal calcium hydroxide dressing correlated with bacterial presence (P < 0.05). CONCLUSIONS: Once established, nonmutans streptococci, enterococci and lactobacilli appear to survive commonly following root-canal treatment of teeth with clinical and radiographical signs of apical periodontitis.

Adolescent↗

PubMed2002

A protocol for polymerase chain reaction detection of Enterococcus faecalis and Enterococcus faecium from the root canal.

AIM: The present study was set up to develop a protocol for detection of Enterococcus faecalis and Enterococcus faecium from the root canal. METHODOLOGY: A collection of type strains and clinical isolates ol E. faecalis and faecium was used. Specific polymerase chain reaction (PCR) primers targeted against the 16S/23S rDNA intergenic region were used and PCR reactions were set up. PCR products were run on TBE-agarose gel and analysed. The sensitivity of the PCR systems was studied using serial dilutions of (i) bacterial DNA and (ii) bacterial cells from E. faecalis. The specificity of the identification was tested against closely related species. RESULTS: All strains of E. faecalis and E. faecium produced identical amplicon profiles composed of two major bands corresponding to sizes of 320 and 420 bp. When amplifying DNA of higher purity, a third band of 600 bp became evident as well. Closely related species demonstrated single bands of various sizes and were easily distinguished from enterococci. The detection level of DNA from serial dilutions of DNA was 10(-13) g. The DNA extraction protocol from bacterial cell suspensions resulted in a detection level of 10 bacterial cells per sample. CONCLUSIONS The present study demonstrated a good potential for using PCR technology in the detection of F. faecalis and E. faecium from root canal samples. With a high specificity the methodology was able to detect 10 cells of E. faecalis.

Base Pairing↗

PubMed2000

Identification and antimicrobial susceptibility of enterococci isolated from the root canal.

Enterococci are occurring in opportunistic infections involving the oral cavity. This study has identified enterococcal species in 29 endodontic infections undergoing treatment with Ca (OH)2 dressings. The in vitro antimicrobial susceptibility of 29 isolated enterococcal strains was determined. Enterococcus faecalis was speciated for 26 isolates and Enterococcus faecium for three isolates. In vitro antimicrobial susceptibility testing revealed enterococcal isolates resistant to benzylpenicillin, ampicillin, clindamycin, metronidazole and tetracycline but sensitive to erythromycin and vancomycin. Due to low sensitivity to antimicrobial agents, enterococci may be selected in root canals undergoing standard endodontic treatment and significantly contribute to endodontic treatment failures.

Ampicillin↗

PubMed1999

The antimicrobial effect of calcium hydroxide in root canals pretreated with 5% iodine potassium iodide.

Calcium hydroxide (CH) is often used as a routine interappointment dressing during the endodontic treatment of teeth with apical periodontitis. However, it fails to consistently produce sterile root canals. The present study was set up to find out whether an antimicrobial strategy including the use of CH could be made more effective if: 1) canals were pretreated with 5% iodine potassium iodide (IPI), and 2) the dressing period was extended up to 2 months. Fifty human teeth, with radiographically verified apical periodontitis, were microbiologically sampled. After chemomechanical preparation the canals were pretreated with IPI for 3-7 days. Teeth where microorganisms persisted were then treated with CH for 2 months. Following instrumentation and dressing with IPI, 43 bacterial strains were recovered in 22 of the teeth. Samples obtained after the CH dressing period disclosed growth of 13 facultative and two strict anaerobic strains in 10 teeth. Enterococcus faecalis was identified in two specimens. In conclusion, the present study gave no evidence for an increased antimicrobial effect of CH if it was left for longer periods in the root canal. Although pretreatment with IPI from a quantitative point of view did not seem to add antimicrobial power, it might reduce the frequency of persisting strains of E. faecalis.

Adult↗

PubMed1999

The diagnostic accuracy of microbiologic root canal sampling and the influence of antimicrobial dressings.

The routine approach to endodontic treatment of teeth with apical periodontitis often involves an interappointment dressing with calcium hydroxide. However, investigations have demonstrated a negative influence of calcium hydroxide on the accuracy of microbiological root canal sampling (MRS). The aim of the present study was to investigate whether the use of a fluid dressing like 5% iodine potassium iodide (IPI) would increase the accuracy of MRS. Following instrumentation of 50 teeth with radiographically verified apical periodontitis the root canals received IPI as an intracanal dressing. One week after closure canals were sampled, "test sample" (TS), and then left filled with sampling fluid and temporarily scaled. Seven days later a "gold standard" (GS) sample was obtained. Bacteria were recovered in 22 teeth (44%) in TS as well as in GS. Fifteen teeth (30%) were positive for growth in both samples. Using the detection level "very sparse growth" of microbes the sensitivity and specificity of MRS reached 68% and 75%, respectively. In an earlier study, following the same experimental protocol, but with calcium hydroxide as intracanal dressing, the corresponding values were 33% and 81%. In 25% of these cases bacteria persisted in the canals. As compared to calcium hydroxide, the use of IPI resulted in improved test accuracy, but loss of antibacterial capacity. Conclusively, intracanal dressings seem to vary in their influence on the microbiologic test performance as well as in their antibacterial efficacy. In a clinical situation the choice of interappointment dressing should include consideration of these potentially conflicting properties.

Adult↗

PubMed1998

Man-made superantigens: Tumor-selective agents for T-cell-based therapy.

Superantigens (SAgs) are a collection of bacterial and viral proteins with potent immunostimulatory properties. SAgs bind to Major Histocompatibility Complex Class II (MHC II) molecules of antigen presenting cells (APCs) and activate a high frequency of T lymphocytes. To target a T-cell attack against tumor cells we genetically linked tumor-specific antibody Fab fragments to the SAg Staphylococcal enterotoxin A (SEA). Fab-SEA fusion protein efficiently targeted to solid tumors and induced a T-cell-mediated eradication of established metastases in animal models. Successful therapy was T-cell-dependent and required tumor specificity of the Fab moiety of the Fab-SEA fusion protein. Due to the high affinity of SAg for MHC II, a limitation of this approach was retention of Fab-SEA proteins in normal tissues expressing MHC II, which caused systemic immune activation and dose limiting toxicity. We recently solved the structure of SEA and applied structure-based drug design to develop a novel generation of 'man-made' SAg with improved pharmacological and pharmacokinetic properties. Mutation of the major MHC II binding site of SEA substantially reduced retention in MHC II(+) tissues and systemic toxicity, while local immune activation at targeted tumor sites was retained. The Fab-SEA mutants display a 10000-fold higher affinity for tumor tissue compared to normal tissue and the therapeutic window was improved >100-fold compared to native Fab-SEA protein. Thus protein engineering can be applied to convert harmful bacterial toxins into tolerable tumor-specific agents.

Journal Article↗

PubMed1998

Microbiological status of root-filled teeth with apical periodontitis.

The present study examined the microbiological status of 100 root-filled teeth with radiographically verified apical periodontitis--the pathology (P) group--and of 20 teeth without signs of periapical pathosis--the technical (T) group. In the P group 117 strains of bacteria were recovered in 68 teeth. In most of the cases examined one or two strains were found. Facultative anaerobic species predominated among these isolates (69% of identified strains). Growth was classified as 'sparse' or 'very sparse' in 53%, and as 'heavy' or 'very heavy' in 42%. Enterococci were the most frequently isolated genera, showing 'heavy' or 'very heavy' growth in 25 out of 32 cases (78%). In 11 teeth of the T group no bacteria were recovered, whilst the remaining nine yielded 13 microbial strains. Eight of these grew 'very sparsely'. It is concluded that the microflora of the obturated canal differs from that found normally in the untreated necrotic dental pulp, quantitatively as well as qualitatively. Nonsurgical retreatment strategies should be reconsidered.

Bacteria, Anaerobic↗

PubMed1996

Microbiological root canal sampling: diffusion of a technology.

Diffusion is the process whereby a technology enters and becomes part of the health-care system. In the present study, diffusion of microbiological root canal sampling (MRS) among general dental practitioners within the city of Gothenburg was observed for 25 years, from the establishment of the Laboratory of Oral Microbiology in 1966. Laboratory records at 5-year intervals were analysed and adopters were categorized as 'occasional' (1-2 samples/year), 'selective' (3-10) or 'regular' (> 10) samples. The diagnostic accuracy was assessed by analysing the results of culturing 574 samples referred in 1986. The acceptance rate varied between 2.9 and 5.1% except in 1986 when 10.1% of the practitioners in the area referred root-canal samples. While a minority of the adopters used MRS as a standard procedure, the strategy appeared to be directed towards selection of special cases. The results of culturing revealed a predominance of facultatives. Although evidence of contamination was found, the practitioners frequently appeared to produce valid microbiological samples.

Bacteriological Techniques↗

PubMed1996

Reasons for dentists' acceptance or rejection of microbiological root canal sampling.

Microbiological root canal sampling (MRS) has been found to be used by only a few Swedish general dentists. The present study addresses the reasons for their acceptance or rejection of the technology. A questionnaire was mailed to 240 general dentists practising within the city of Göteborg. The questionnaire concerned certain practice characteristics and attitudes to MRS. The data showed that MRS is mainly performed by dentists working with adult patients in private practice. The technology is rarely used routinely, but is applied in selected cases. The main reason for non-adoption seems to be a perceived lack of relative advantage over conventional treatment strategies. Furthermore, opinions regarding the complexity and observability of the technology appear to influence acceptance significantly.

Attitude of Health Personnel↗

PubMed1990

Microbiological evaluation of clindamycin as a root canal dressing in teeth with apical periodontitis.

The present investigation was designed to study the effect of clindamycin on root canal infection when placed as an intracanal dressing. Twenty-five teeth with necrotic pulps and periapical radiolucencies were included. Following initial bacteriological sampling and routine instrumentation, clindamycin powder mixed to a paste with saline was applied for 14 days. The presence or absence of bacteria was determined in samples taken immediately after removal of the dressing, and after a period of 7 days during which the canals were filled with sampling fluid. Bacteria were recovered from four and six teeth respectively. The results indicated that clindamycin offered no advantage over conventional root canal dressings, such as calcium hydroxide, and it is therefore not recommended for use in routine endodontic therapy.

Clindamycin↗

PubMed1990

Observations on biochemical and haematological parameters in healthy people above 80 years of age.

Ninety-five apparently healthy people, aged 80 years or above, living in the Stockholm County Council of Sweden, participated in a pilot study in 1984. Reference values were obtained for routine haematological and biochemical analyses. Deviations from expected levels were confined to thyroid-stimulating hormone (TSH), vitamin B12 and calcium. It is noteworthy that a low-risk cholesterol level characterized this elderly population. It is suggested that in order to evaluate the influence of age, a dynamic aspect should be added using functional tests of various organs.

Aged↗