Elin Giertsen

• Giertsen, Elin; Arthur, Rodrigo Alex & Guggenheim, Bernhard (2011). Effects of Xylitol on Survival of Mutans Streptococci in Mixed-Six-Species in vitro Biofilms Modelling Supragingival Plaque. Caries Research.  ISSN 0008-6568.  45(1), s 31- 39 . doi: 10.1159/000322646
• Quevedo, B; Giertsen, Elin; Zijnge, V; Lüthi-Schaller, H; Guggenheim, B; Thurnheer, T & Gmür, R (2011). Phylogenetic group- and species-specific oligonucleotide probes for single-cell detection of lactic acid bacteria in oral biofilms. BMC Microbiology.  ISSN 1471-2180.  11:14 . doi: 10.1186/1471-2180-11-14
• Thurnheer, T; Giertsen, Elin; Gmur, R & Guggenheim, B (2008). Cariogenicity of soluble starch in oral in vitro biofilm and experimental rat caries studies: a comparison. Journal of Applied Microbiology.  ISSN 1364-5072.  105, s 829- 836 . doi: 10.1111/j.1365-2672.2008.03810.x
• Giertsen, Elin (2007). Orale biofilmmodeller - nye muligheter for plakkstudier. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  117, s 794- 802
• Gmür, Rudolf; Giertsen, Elin; van der Veen, Monique H.; de Josselin de Jong, Elbert; ten Cate, Jacob M. & Guggenheim, Bernhard (2006). In vitro quantitative light-induced fluorescence to measure changes in enamel mineralization. Clinical Oral Investigations.  ISSN 1432-6981.  10(3), s 187- 195 . doi: 10.1007/s00784-006-0058-z
• Gmur, R; Giertsen, Elin; van der Veen, MH; de Jong, ED; ten Cate, JM & Guggenheim, B (2006). In vitro quantitative light-induced fluorescence to measure changes in enamel mineralization. Clinical Oral Investigations.  ISSN 1432-6981.  10, s 187- 195
• Thurnheer, Thomas; Van der Ploeg, Jan R.; Giertsen, Elin & Guggenheim, Bernhard (2006). Effects of Streptococcus mutans gtfC deficiency on mixed oral biofilms in vitro. Caries Research.  ISSN 0008-6568.  40(2), s 163- 171 . doi: 10.1159/000091065
• Giertsen, Elin (2005). Håndhygiene i tannlegepraksis - hånddesinfeksjon. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  115, s 675- 675
• Giertsen, Elin (2005). Mikrobiell økologi og dentale biofilmer. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  115, s 388- 389
• Giertsen, Elin (2004). Effects of Mouthrinses with Triclosan, Zinc Ions, Copolymer and Sodium Lauryl Sulphate combined with Fluoride on Acid Formation by Dental Plaque in vivo. Caries Research.  ISSN 0008-6568.  38, s 430- 435
• Guggenheim, Bernhard; Guggenheim, Merlin; Gmür, Rudolf; Giertsen, Elin & Thurnheer, Thomas (2004). Application of the Zurich biofilm model to problems of cariology. Caries Research.  ISSN 0008-6568.  38, s 212- 222
• Van der Ploeg, Jan R.; Giertsen, Elin; Lüdin, Beat; Mörgeli, Christian; Zinkernagel, Annelies & Gmür, Rudolf (2004). Quantitative detection of Porphyromonas gingivalis fimA genotypes in dental plaque. FEMS Microbiology Letters.  ISSN 0378-1097.  232, s 31- 37
• Shapiro, S; Giertsen, Elin & Guggenheim, B (2002). An in vitro oral biofilm model for comparing the efficacy of antimicrobial mouthrinses. Caries Research.  ISSN 0008-6568.  36, s 93- 100.
• Guggenheim, Bernhard; Giertsen, Elin; Schüpbach, Peter & Shapiro, Stuart (2001). Validation of an in vitro Biofilm Model of Supragingival Plaque. Journal of Dental Research.  ISSN 0022-0345.  80(1), s 363- 370. Vis sammendrag

  The study of biofilm structure and function mandates the use of model systems for which a host of environmental variables can be rigorously controlled. We describe a model of supragingival plaque containing Actinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis wherein cells are cultivated anaerobically in a saliva-based medium on hydroxyapatite discs coated with a salivary pellicle, with material and pieces of apparatus common to all microbiology laboratories. After 0.5 hr, 16.5 hrs, 40.5 hrs, and 64.5 hrs, the composition of adherent biofilms was analyzed by culture techniques, live/dead fluorescence staining, and confocal laser scanning microscopy. Repeated independent trials demonstrated the repeatability of biofilm formation after 40.5 hrs and 64.5 hrs. Brief exposures of biofilms to chlorhexidine or Triclosan produced losses in viability similar to those observed in vivo. This biofilm model should prove very useful for pre-clinical testing of prospective anti-plaque agents at clinically relevant concentrations.

• Thurnheer, Thomas; Gmür, Rudolf; Giertsen, Elin & Guggenheim, Bernhard (2001). Automated fluorescent in situ hybridization for the specific detection and quantification of oral streptococci in dental plaque. Journal of Microbiological Methods.  ISSN 0167-7012.  44(1), s 39- 47. Vis sammendrag

  Our aim was to develop a rapid fluorescent in situ hybridization (FISH) assay for the identification of different oral groups of streptococci in dental plaque and to combine it with digital image analysis for the automated enumeration of target cells. Cy3-labeled oligonucleotide probes specific for 16S rRNA gene sequences of the anginosus, mitis, mutans, and salivarius groups of streptococci were hybridized under stringent conditions with bacterial cultures or supragingival plaque samples that had been permeabilized with lysozyme. Probe specificity was determined with strains from 30 different species, mainly of oral origin. Results showed that probes ANG541, MIT447, SSP001, and SAL090 with specificity for the anginosus, mitis, mutans, and salivarius groups, respectively, the pan-reactive streptococcal probe STR405, the S. mutans specific probe MUT590, and the S. Sobrinus specific probe SOB174 were well-suited for the identification of cultured streptococci. Probes STR405, MIT447 and SSP001 were then successfully applied to enumerate automatically bacteria of the recognized taxa in 144 supragingival plaque samples. On the average, total streptococci accounted for 8.2%, streptococci of the mitis and mutans groups for 3.9 and 1.7%, respectively, of the plaques. The combined application of FISH and automated image analysis provides an objective time-saving alternative to culture or PCR for the enumeration of selected oral streptococci in dental plaque.

• Thurnheer, Thomas; Gmür, Rudolf; Giertsen, Elin & Guggenheim, Bernhard (2001). Automated fluorescent in situ hybridization for the specific detection and quantification of oral streptococci in dental plaque. Journal of Microbiological Methods.  ISSN 0167-7012.  44(1), s 39- 47. Vis sammendrag

  Our aim was to develop a rapid fluorescent in situ hybridization (FISH) assay for the identification of different oral groups of streptococci in dental plaque and to combine it with digital image analysis for the automated enumeration of target cells. Cy3-labeled oligonucleotide probes specific for 16S rRNA gene sequences of the anginosus, mitis, mutans, and salivarius groups of streptococci were hybridized under stringent conditions with bacterial cultures or supragingival plaque samples that had been permeabilized with lysozyme. Probe specificity was determined with strains from 30 different species, mainly of oral origin. Results showed that probes ANG541, MIT447, SSP001, and SAL090 with specificity for the anginosus, mitis, mutans, and salivarius groups, respectively, the pan-reactive streptococcal probe STR405, the S. mutans specific probe MUT590, and the S. sobrinus specific probe SOB174 were well-suited for the identification of cultured streptococci. Probes STR405, MIT447 and SSP001 were then successfully applied to enumerate automatically bacteria of the recognized taxa in 144 supragingival plaque samples. On the average, total streptococci accounted for 8.2%, streptococci of the mitis and mutans groups for 3.9 and 1.7%, respectively, of the plaques. The combined application of FISH and automated image analysis provides an objective time-saving alternative to culture or PCR for the enumeration of selected oral streptococci in dental plaque.

• Giertsen, Elin; Guggenheim, Bernhard; Thurnheer, Thomas & Gmür, Rudolf (2000). Microbiological aspects of an in situ model to study effects of antimicrobial agents on dental plaque ecology. European Journal of Oral Sciences.  ISSN 0909-8836.  108(5), s 403- 411. Vis sammendrag

  This study validates an in situ model for ecological studies of dental plaque exposed to various antimicrobial agents with different modes of action on plaque bacteria. Eleven subjects wore two acrylic appliances, each containing two bovine enamel discs, during two 1-wk test periods. Using a split-mouth crossover design, the appliances were dipped twice daily for 1 min into water (control; treatment A), fluoride (26.3 mM NaF;B), zinc acetate (20.0 mM;C), or fluoride plus zinc acetate (D). Four of the subjects used also chlorhexidine diacetate (2.2 mM;E) and chlorhexidine plus fluoride (F). At the end of each period, plaque was collected from the discs, after which the microbiota were analyzed by culture, automated quantitative immunofluorescence, and a viability fluorescence stain. As compared to control, treatments B, C, and D resulted in a significant reduction of individual taxa as detected by immunofluorescence, whereas similar bacterial viability and total bacterial numbers were observed. In contrast, chlorhexidine significantly reduced bacterial viability, total cell numbers, and the abundance of most of the enumerated taxa. We conclude that this in situ model is well suited to study effects of antimicrobial agents on dental plaque ecology. Combined with viability testing, immunofluorescence is obviously superior to culture in detecting taxa-specific shifts caused by antimicrobial agents.

• Gmür, Rudolf; Guggenheim, Bernhard; Giertsen, Elin & Thurnheer, Thomas (2000). Automated immunofluorescence for enumeration of selected taxa in supragingival dental plaque. European Journal of Oral Sciences.  ISSN 0909-8836.  108(5), s 393- 402. Vis sammendrag

  The present study investigated a recently developed automated image analysis technique for its applicability to the enumeration of selected bacteria in supragingival dental plaque. Following initial calibration, the system is capable to count fluorescence labeled target cells in up to 48 samples without user interference. Test samples contained a characteristic mixture of planktonic bacteria, small almost planar bacterial aggregates, and large, virtually indisruptable clumps with cells from multiple species. Due to their complex composition, these samples provided a challenging validation step for the image analysis system. Automated enumeration of target bacteria was compared with visual counting of the fluorescence-labeled bacteria. Results are shown for six taxa (Actinomyces naeslundii, Fusobacterium nucleatum, Prevotella intermedia/Prev. nigrescens, Streptococcus gordonii/Strep. oralis/Strep. sobrinus and Veillonella dispar/V. parvula) with characteristic differences in abundance, cell morphology and aggregation behavior. Results revealed good correspondence between the two enumeration techniques (correlation coefficients ranging from 0.77 to 0.92) provided that the portion of target bacteria exceeded 0.05% of the total baterial cell number. This work demonstrates the applicability and usefulness of fully automated immunofluorescence to analyze such complex ecosystems as supragingival dental plaque.

• Giertsen, Elin; Emberland, Hege & Scheie, Anne Aamdal (1999). Effects of Mouth Rinses with Xylitol and Fluoride on Dental Plaque and Saliva. Caries Research.  ISSN 0008-6568.  33(1), s 23- 31. Vis sammendrag

  The aim of this study was to test the hypothesis that xylitol, alone and in combination with fluoride, affects the salivary flow rate and micro-biota, dental plaque accumulation, gingivitis development, and the acidogenic potential of plaque. Three groups, each of 10 subjects, rinsed for 1 min 3 times daily over two 4-week periods, first with 10 ml water (control), and thereafter with either 0.05% NaF, 40% xylitol, or with 0.025% NaF plus 20% xylitol according to a double-blind controlled design. They performed habitual mechanical tooth cleaning during the first 2 weeks of each period but abstained from interdental cleaning during the final 2 weeks. While mouth rinsing was continued, all mechanical oral hygiene was discontinued the last 2 days of each period to permit plaque accumulation. The last mouth rinse was administered in the clinic before the final examination. The following parameters were assessed: (1) unstimulated and paraffin-stimulated salivary secretion rates; (2) salivary micro-biota; (3) plaque index; (4) papillar bleeding; (5) plaque pH response to sucrose, and (6) lactate formation by dental plaque. No statistically significant differences in any of the parameters were found. In conclusion, three daily mouth rinses with fluoride and xylitol, separately or in combination, did not affect the salivary flow rate or micro-biota, dental plaque accumulation, gingivitis development, or the acidogenic potential of plaque.

• Arneberg, Pål; Giertsen, Elin; Emberland, H. & Øgaard, B (1997). Intra-Oral Variations in Total Plaque Fluoride Related to Plaque pH. A Study in Orthodontic Patients. Caries Research.  ISSN 0008-6568.  31, s 451- 456. Vis sammendrag

  The aim of the present investigation was to study intra-oral variations in total plaque fluoride, and to examine whether such variations were related to plaque pH. Five orthodontic patients abstained from oral hygiene and daily fluoride rinsing for 2 days. Resting and fermenting plaque pH was measured with a touch micro-electrode at 14-21 localized sites on bonded vestibular tooth surfaces in each subject. Plaque samples from the same sites were analysed with a fluoride micro-electrode. A wide range of plaque pH values and fluoride concentrations were observed. In all subjects plaque pH and total fluoride levels were lower at upper than at lower front teeth. A direct log-linear relationship existed between total fluoride and fermenting plaque pH. In 4 of the 5 subjects this relationship was statistically significant (p<0. 05) and quite strong (adjusted R2 0.2-0.5, Beta 0.5-0.7). The study shows significant intra-oral variations in total plaque fluoride related to plaque pH.

• Giertsen, Elin (1996). Plakkhemmende stoffer - er de effektive?. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  106, s 484- 490. Vis sammendrag

  Artikkelen omhandler plakkhemmende stoffer som finnes i tannpleieprodukter her i landet. Grunnlag og mål for bruk av plakkhemmende stoffer omtales først. Deretter gjennomgås aktuelle stoffer, deres antatte virkemåte og effekt på plakk. Videre diskuteres hvor effektive stoffene er med hensyn på å hemme sykdomsutvikling og derved indikasjoner for bruk. Det konkluderes med at klorhexidin fremdeles er det eneste middelet i handelen som har plakkhemmende effekt av betydning.

• Giertsen, Elin & Scheie, Anne Aamdal (1996). Antibakteriell virkning på plakk av klorhexidin-fluorid munnskylling. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  106, s 276- 280. Vis sammendrag

  Klorhexidins enestående plakkhemmende effekt tilskrives hovedsaklig en langvarig bakteriostase av plakkbakterier. Klorhexidin absorberes til munnslimhinne, tannplakk og pellikel etter munnskylling. Stoffet avgis derette langsomt fra bindingsstedene, og det antas at bakteriostatiske konsentrasjoner opprettholdes i plakk og saliva i flere timer etter applikasjon. Denne depoteffekten antas således å redusere bakteriell metabolsk aktivitet og derved forhindre formering og vekst av bakterier i munnhulen melom munnskyllingene. Målet med denne undersøkelsen var å studere effekten av munnskyllinger med klorhexidin kombinert med fluorid på plakkviabilitet og syreproduksjon i plakk for å bestemmme betydningen av den bakteriedrepende kontra den bakteriostatiske effekten for hemningen av syreproduksjonen i plakk. Resultatene viser at den syrehemende effekten av klorhexidin på plakk kan relateres direkte til reduksjon av bakterietallet i plakk. Våre funn tyder derfor på at hemningen av syreproduksjonen i plakk av klorhexidin munnskylling i hovedsak skyldes en øyeblikkelig bakteriedrepende virkning på bakterier i plakk snarere enn en langvarig bakteriostase mellom munnskyllingene. Dette er av betydning fordi klorhexidins virkningsmekanisme i utstrakt grad brukes som modell for virkningsmekanismen for munnskyllinger med plakkhemmende stoffer generelt.

• Giertsen, Elin & Scheie, A.Aa (1995). Effects of Chlorhexidine-Fluoride Mouthrinses on Viability, Acidogenic Potential, and Glycolytic Profile of Established Dental Plaque. Caries Research.  ISSN 0008-6568.  29, s 181- 187. Vis sammendrag

  Inhibition of dental plaque acidogenicity by chlorhexidine (CHX) mouthrinses has been ascribed to a long-lasting bacteriostatic effect due to binding of CHX to oral surface structures combined with a slow release rate from the binding sites. The present aims were to study the effects of CHX-containing mouthrinses on the viability and glycolytic activity of established plaque in order to assess the bactericidal versus the bacteriostatic effects. Following 2 days of plaque accumulation, three groups of 10 students rinsed with either 12.0 mM NaF, 0.55 mM CHX plus NaF, or with 2.2 mM CHX plus NaF. Plaque samples were collected before and 90 min after mouthrinsing. The pH in pooled pre- and post-rinse plaque samples was recorded before and up to 10 min after the addition of D-[U-14C] glucose. Total colony-forming units in each sample were determined. High-performance liquid chromatography analyses showed lactate to be the major extracellular glycolytic metabolite in all samples. CHX-NaF markedly reduced the colony-forming units, the pH fall from fermentation of glucose, as well as glucose consumption and lactate formation, whereas NaF alone exhibited no such effects. The reduction of glucose consumption by the CHX-NaF mouthrinses corresponded to the reduction of colony-forming units, indicating no bacteriostatic effect. The plaque pH in vivo was monitored in each student 90 min after mouthrinsing with the test solutions prior to and up to 1 h after a sucrose mouthrinse using touch microelectrodes. The CHX-NaF mouthrinses reduced the fall in pH significantly (p<0.05) as compared with the NaF mouthrinse. The results suggested that the reduced acid formation by dental plaque following a CHX mouthrinse is due to a bactericidal effect rather than a long-lasting bacteriostatic action.

• Giertsen, Elin & Scheie, A.Aa (1995). Effects of mouthrinses with chlorhexidine and zinc ions combined with fluoride on the viability and glycolytic activity of dental plaque. European Journal of Oral Sciences.  ISSN 0909-8836.  103, s 306- 312. Vis sammendrag

  Inhibition of plaque acidogenicity by a mouthrinse with chlorhexidine (CHX) or zinc ions has been ascribed to a prolonged bacteriostasis due to substantive properties of the agents. The present aim was to study the effects of mouthrinses with CHX and Zn ions combined with fluoride on the viability and glycolytic activity of dental plaque in order to assess the bacteriostatic versus possible bactericidal effects. Following 2 d of plaque accumulation, 4 groups of 10 students rinsed with either 12 mM NaF (F), 0.55 mM CHX diacetate+F (F-CHX), 10 mM Zn acetate+F (F-Zn), or with the three agents in combination (F-CHX-Zn). Plaque samples were collected before and 90 min after mouthrinsing. Thereafter, the in vivo plaque pH response to sucrose was monitored in each student using touch microelectrodes. F-CHX and F-CHX-Zn reduced the in vivo pH fall significantly as compared with F, whereas F-Zn exerted a non-significant inhibition. Pooled pre- and post-rinse plaque samples were used to measure the pH fall during fermentation of [14C] glucose, and the glycolytic profiles were analyzed by HPLC. Bacterial viability was assessed by counting the colony-forming units (CFU). All mouthrinses except F reduced glucose consumption and acid formation and thus the pH fall. F-CHX reduced the CFU equal to the reduction of glucose consumption, indicating that inhibition of plaque acidogenicity was due to a bactericidal rather than a bacteriostatic effect. F and F-Zn did not reduce the CFU, thus F-Zn decreased glucose metabolism without affecting plaque viability. F-CHX-Zn reduced both the CFU and glucose metabolism of surviving plaque microorganisms.

• Giertsen, Elin & Scheie, A.Aa (1993). In vivo effects of fluoride, chlorhexidine, and zinc ions on acid formation by dental plaque and salivary mutans streptococcus counts in patients with irradiation-induced xerostomia. Oral Oncology.  ISSN 1368-8375.  29B(4), s 307- 312.

Se alle arbeider i Cristin

• Giertsen, Elin (2016, 22. februar). Skånsomme tannkremer. [Fagblad].  Norsk Ukeblad nr. 8/16 s. 18-22.
• Young Vik, Alix & Giertsen, Elin (2015). Sukkererstatninger og tannhelse: Har xylitol antikariogen effekt?.
• Giertsen, Elin & Jacobsen, Svein (2012). W.D. Miller: Pioneren som løste kariesgåten. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  122(6), s 446- 450.
• Giertsen, Elin (2011). Kolonisering av ikke-orale Gram-negative bakterier i munnen. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  121(10), s 658- 659.
• Guggenheim, B; Meier, A; Hofer, D; Schmidlin, P; Arthur, RA & Giertsen, Elin (2011). Adherence and Persistence of Gram- Non-Oral Bacteria in the Mouth. Journal of Dental Research.  ISSN 0022-0345.  90: Spec Iss A, Abstract 2957(IADR/AADR/CADR, San Diego, CA, USA, 16.-19.03.2011)
• Giertsen, Elin (2010). Betydning av spesifikk adhesjon for kolonisering av orale mikroorganismer. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  120(10), s 723- 724.
• Giertsen, Elin (2010). Type 2-diabetes og tannhelse.
• Giertsen, Elin; Olsen, Ingar & Guggenheim, Bernhard (2010). Importance of Specific Adherence for Colonization of Microorganisms in the Oral Cavity.
• Guggenheim, B; Arthur, R; Schmidlin, P; Hofer, D & Giertsen, E (2010). Role of Specific Adherence for Colonization Sequence of Oral Microbiota. Journal of Dental Research.  ISSN 0022-0345.  89: Spec Iss B, Abstract 125(IADR/AADR 88th General Session, Barcelona, Spania)
• Quevedo, B; Giertsen, E; Zijnge, V; Lüthi-Schaller, H; Guggenheim, B; Thurnheer, T & Gmür, R (2010). Identification and Enumeration of Lactic Acid Bacteria by FISH. Journal of Dental Research.  ISSN 0022-0345.  89: Spec Iss B, Abstract 3686(IADR/AADR 88th General Session, Barcelona, Spania)
• Arthur, Rodrigo; Meier, André; Guggenheim, Bernhard & Giertsen, Elin (2009). Development of a Local Demineralization Biofilm Model to Study the Cariogenic Potential of Oral Bacteria.
• Giertsen, Elin (2009). Alternative søtningsmidler - betydning for generell og oral helse.
• Giertsen, Elin (2009). Orale biofilmmodeller-nye muligheter for plakkstudier.
• Giertsen, Elin (2009). Tannpleiemidler - hva består de av og hvorfor.
• Giertsen, Elin (2009). Type 2-diabetes og tannhelse.
• Giertsen, Elin; Olsen, Ingar; Petersen, Fernanda Cristina & Scheie, Anne Aamdal (2009). Oral biofilm. Jubileumshefte for Det odontologiske fakultet.  s 17- 19.
• Giertsen, Elin (2008). Orale biofilmmodeller - nye muligheter for plakkstudier.
• Giertsen, Elin (2008). Type 2-diabetes og tannhelse.
• Giertsen, Elin (2007). Orale biofilmmodeller - nye muligheter for plakkstudier.
• Giertsen, Elin; Guggenheim, B & Gmür, R (2007). Antiplaque effects of ethyl lauroyl arginine in situ.
• Giertsen, Elin (2006). Orale biofilmer - nye muligheter for plakkstudier.
• Thurnheer, Thomas; Giertsen, Elin & Guggenheim, Bernhard (2006). Effect of starch on microbial composition, structure, diffusion properties and demineralization potential of oral biofilms.
• Giertsen, Elin (2005). Does xylitol work in biofilms?.
• Giertsen, Elin & Guggenheim, Bernhard (2005). Effect of xylitol on survival of mutans streptococci in biofilms. Journal of Dental Research.  ISSN 0022-0345.  84: Spec Iss A, Abstract 1506(IADR/AADR/CADR, Baltimore, Maryland, USA)
• Guggenheim, Bernhard & Giertsen, Elin (2005). Impact of biofilm research on dentistry.
• Guggenheim, Bernhard; Gmür, Rudolf & Giertsen, Elin (2005). Starch: Effect on microbial composition and demineralization potential. Journal of Dental Research.  ISSN 0022-0345.  84: Spec Iss A, Abstract 1509(IADR/AADR/CADR, Baltimore, Maryland, USA)
• Thurnheer, Thomas; van der Ploeg, Jan R.; Giertsen, Elin & Guggenheim, Bernhard (2005). Effects of Streptococcus mutans gtf-deficiency on mixed oral biofilms in vitro.
• Guggenheim, Bernhard & Giertsen, Elin (2004). Comparative Effect of Antimicrobials in Biofilm Versus an Animal Study.
• Giertsen, Elin (2003). In vitro biofilmmodell. In situ kariesmodell.
• Guggenheim, B; Giertsen, Elin & Gmür, R (2003). Demineralization and remineralization of enamel in the Zürich biofilm model. Journal of Dental Research.  ISSN 0022-0345.  82: Spec Iss B: B-244, Abstract 1861(IADR, Göteborg, Sverige, juni 2003)
• Guggenheim, B; Gmür, R; van der Ploeg, JR; Giertsen, Elin & Thurnheer, T (2003). Impact of biofilm models in preventive dentistry.
• van der Ploeg, JR; Giertsen, Elin; Lüdin, B; Mörgeli, C; Zinkernagel, AS & Gmür, R (2003). Quantitative detection of Porphyromonas gingivalis fimbrial genotypes in Europeans. Journal of Dental Research.  ISSN 0022-0345.  82: Spec Iss B: B-248, Abstract 1894(IADR, Göteborg, Sverige, juni 2003)
• Guggenheim, B. & Giertsen, Elin (2002). Comparative antimicrobial efficacy of antiplaque agents in a biofilm model.
• Lygre, Henning; Moe, Grete; Holmsen, Holm; Skålevik, Rita & Giertsen, Elin (2002). Interaction of triclosan and membrane lipids. Vis sammendrag

  The possibility that triclosan and PVM/MA (polyvinylmethyl ether/maleic acid) copolymer, additives to dentifrices, could interact with eukaryotic membrane lipids was studied by two methods: First, by determining the pressure/molecular area isotherms at 37oC of glycerophospholipids monolayers, using the Langmuir technique; second, by phase transition parameters in liposomes of the same lipids, using differential scanning calorimetry (DSC). Triclosan interacted, in a concentration-independent manner, with monolayers of saturated phosphatidylcholines (PC, i.e. markers of the outer membrane leaflet of eukaryotic cells). Triclosan and PVM/MA copolymer mixtures were shown to clearly interact in a concentration-dependent manner with PC. Triclosan was found to interact with liposomes of saturated and unsaturated phosphatidylcholines and -serines (PS, i.e. markers of the inner membrane leaflet of eukaryotic cells), and saturated ethanolamines (PE, i.e. markers of the inner membrane leaflet of eukaryotic cells), resulting in a decrease of the lipid melting temperature (Tm). PVM/MA copolymer changed the Tm of PS, PC and PE in different manners. By adding PVM/MA or triclosan-PVM/MA copolymer mixtures to SOPS no lipid transitions were detected. A biphasic change of the PC transition temperature resulted when triclosan or triclosan-PVM/MA copolymer mixtures were added, indicating domain formation and change of the lipid polymorphism.

• Shapiro, S.; Giertsen, Elin & Guggenheim, B (2002). Comparative efficacies of antimicrobial mouthrinses in a modified biofilm model.
• Giertsen, Elin (2001). Fluorinnhold i tannkremer. NORTANN (Personalavis for Den offentlige tannhelsetjenesten i Nordland).  11, s 10- 11.
• Giertsen, Elin (2001). Forskningsrapport i Fasett 2001; Volum 36: s. 30-33, I: [Mangler fornavn] [Mangler etternavn] (red.),  Fasett, Tidsskrift for tannlege- og tanpleierstudenter i Bergen.  Universitetet i Bergen.  Formidling.  s 30 - 33.
• Giertsen, Elin (2001). Hvordan kan vi få mer tverrfaglig forskning med klinisk relevans? Populærvitenskapelig innlegg. "Omorganisering av Laboratorium for odontologisk forskning".
• Giertsen, Elin (2001). Kost og karies.
• Giertsen, Elin; Jacobsen, K & Guggenheim, B (2000). Effects of Caseinoglycomacropeptide, Micellar Casein-Based Drink, and Renneted Milk on Acid Formation by Dental Plaque.
• Giertsen, Elin (1999, 23. juli). Om erosjoner. Intervju.  Bergensavisen, s. 8.
• Schuepbach, P; Lutz, F; Guggenheim, B & Giertsen, Elin (1999). Efficacy of an alkaline glass composite to prevent secondary caries. Vis sammendrag

  The aim of this study was to compare an alkaline glass composite Ariston pHC (treatment A) which releases fluoride-, hydroxyl- and Ca2+-ions with a fluoride releasing glass ionomer cement Ketac. (trt. B) for its efficacy in preventing secondary caries. This was achieved by comparing the two test materials with the non-fluoride releasing Tetric Ceram (trt C) as control. An in situ model was used to evaluate demineralization of enamel across standardized gaps between enamel and filling material. In addition, the effect of the Ariston Liner applied in the gap between Ariston pHC and enamel was assessed (trt. D). Acrylic appliances, attached to teeth 36 and 46, were worn day and night by 8 students during 7 days. Each appliance had two chambers, in each of which a piece of filling material and a piece of bovine enamel separated by a 100 um gap was mounted. The appliances were immersed eight times daily for 10 min in a sugar solution (3% glucose, 3% sucrose, 70 mM NaCl, 70 mM KCI, 2 mM MgCl2, pH 5.5). The extent of demineralization was measured by confocal microscopy. The specimens were stained during 24 h with a 0.1 mM solution of Rhodamine B and then dipped in H2O during 10 s. The specimens were examined under a confocal Axioplan-LM with an attached argon-crypton laser equipped with a water immersion 25x-objective. The digital images were further processed using image-processing software. The median volumes of demineralization of these treatments were: A 1.2x106; B 7.9x106; C 8.3x106 and D 5.8x106 um3, whereby A was significantly (p<0.01) lower than B and C, and D was significantly (p<0.05) lower than C. Ariston pHC in contrast to Ketac substantially reduced demineralization of adjacent enamel. However, its efficacy was markedly reduced by the application of Ariston Liner.

• Thurnheer, T; Giertsen, Elin; Guggenheim, B & Gmür, R (1999). Validation of an automated immunofluorescence technique for supragingival plaque analyses. Vis sammendrag

  The purpose of this study was to validate automated immunofluorescence (IF) for the enumeration of selected species in dental plaque of great complexity. To this end supragingival plaque samples were studied in parallel by Kontron's image processing system (IBAS) connected to a SIT camera-equipped IF microscope and by conventional IF microscopy. 46 plaque samples from an in situ demineralization model were coated to multi-well microscope slides. Wells were IF stained with well characterized monoclonal antibodies specific for Actinomyces naeslundii, Fusobacterium nucleatum, Prevotella intermedia/P. nigrescens, Streptococcus gordonii/S. oralis/S. sanguis, Streptococcus sobrinus, or Veillonella dispar/V. parvula using a standard three-step procedure. Video images from multiple, automatically visited, areas of wells were collected and processed by IBAS to identify and enumerate fluorescent objects of interest. Automated IF-analysis and counting of fluorescently labeled bacteria by eye were performed by different investigators not knowing each others data. Results showed satisfactory levels of correspondence with correlation coefficients of r=0.90 for the S. gordonii group, r=0.79 for A. naeslundii, r= 0.77 for V. parvula/dispar, r=0.91 for P. intermedia/nigrescens, r=0.66 for F. nucleatum, and r=0.73 for S. sobrinus. Differences between the two methods were due to strong aggregation (e.g., A. naeslundii), irregular cell wall IF (S. sobrinus), or very low target cell density (F. nucleatum). This work demonstrates the applicability of automated IF analysis for such complex test systems as supragingival plaques. As with all other microbiological assay techniques, insufficient plaque disaggregation is a concern. Supported by Unilever Research, Port Sunlight, England.

• Giertsen, Elin; Guggenheim, B.; Schüpbach, P. & Gmür, R (1998). In situ model for studies of plaque microbiota and enamel demineralization. Journal of Dental Research.  ISSN 0022-0345.  77: Spec Iss B: Abstract 1206, s. 782(IADR, Nice, Frankrike, 24.06.1998-27.06.1998) Vis sammendrag

  The validity of an in situ model to study dental plaque microbiota and enamel demineralization was tested. Acrylic appliances, attached to teeth 36 and 46 and each containing two bovine enamel discs, were worn day and night by 11 students during two 1-week test periods. The appliances were immersed 8 times daily for 10 min in a glucose/sucrose solution and kept in a phosphate buffer during meals and tooth cleaning. Twice daily each appliance was dipped for 1 min into one of the following four solutions (A-D) using a double-blind, cross-over design: A: H2O (control); B: 26.3 mM NaF; C: 20 mM zinc acetate; D: NaF + zinc. Biofilms from each disc were collected by scraping and resuspended in acetate buffer. The microbiota were analyzed using both non-selective and selective culture techniques. Viability was assessed with the live/dead stain. In addition, total cell numbers (TCN) were determined with the Sytox® stain. Total CFU, total streptococci, mutans streptococci, black pigmented bacteria, and % live cells were within the same range for each treatment. Total CFU and TCN correlated well. Eight plaque samples from treatment A were further analyzed quantitatively for 13 taxa by immunofluorescence (IF) with monoclonal antibodies. Great inter-individual variations in plaque composition were observed; the sum of the 13 taxa studied constituted between 10-97% (mean 34%) of TCN. The extent of demineralization was measured within a defined space of all posterior discs using confocal laser-scanning microscopy. The median volumes of complete demineralization per treatment were: A , 26.3x106 µm3; B, 0.0x106 µm3; C, 4.7x106 µm3; and D, 4.4x106 µm3; whereby B was significantly (p<0.05) lower than the other treatments, and D was significantly (p<0.05) lower than A. With 4 subjects, 2.2 mM chlorhexidine and NaF+CHX were also tested. A marked bactericidal effect and no demineralization resulted. We show that this model is valid to study effects of agents interfering with plaque microbiota and caries formation. Supp. by Colgates forskningsfond, Norway and Norsk Dental Depots fond, Bergen.

• Giertsen, Elin; Schüpbach, P; Lutz, F & Guggenheim, B (1998). An in situ model for dental plaque and demineralization studies. Journal of Dental Research.  ISSN 0022-0345.  77: Spec Iss A: Abstract 1209, s. 257(AADR/CADR, Minneapolis, Minnesota, USA)
• Guggenheim, Bernhard; Schüpbach, P.; Giertsen, Elin & Gmür, R (1998). Validation of a new biofilm model. Vis sammendrag

  The study of biofilm structure and function mandates the use of model systems for which a host of environmental variables can be rigorously controlled. We describe a model of supragingival plaque containing Actinomyces naeslundii, Veillonella dispar, Fusobacterium nucleatum, Streptococcus sobrinus, and Streptococcus oralis wherein cells are cultivated anaerobically in a saliva-based medium on hydroxyapatite discs coated with a salivary pellicle, with material and pieces of apparatus common to all microbiology laboratories. After 0.5 hr, 16.5 hrs, 40.5 hrs, and 64.5 hrs, the composition of adherent biofilms was analyzed by culture techniques, live/dead fluorescence staining, and confocal laser scanning microscopy. Repeated independent trials demonstrated the repeatability of biofilm formation after 40.5 hrs and 64.5 hrs. Brief exposures of biofilms to chlorhexidine or Triclosan produced losses in viability similar to those observed in vivo. This biofilm model should prove very useful for pre-clinical testing of prospective anti-plaque agents at clinically relevant concentrations.

• Giertsen, Elin (1997). A new in situ model for studies of dental plaque and demineralization of enamel.
• Giertsen, Elin (1997). Bactericidal versus bacteriostatic strategies for dental plaque control.
• Giertsen, Elin (1997). In situ biofilm models for studies of dental plaque.
• Giertsen, Elin (1997). Möglichkeiten der Plaqueprävention. Dental Forum.  ISSN 0924-9273.  7(1), s 28- 33.
• Giertsen, Elin (1997). Sukkererstatninger - betydning i kariesprofylaksen? Nyere forskning.
• Giertsen, Elin & Scheie, AAa (1996). Effects of fluoride and xylitol on plaque glycolysis. Journal of Dental Research.  ISSN 0022-0345.  75: Spec Iss: Abstract 646, s. 98(IADR, San Francisco, Calif., USA, 13.03-17.03 1996)
• Giertsen, Elin (1996). Effects of chlorhexidine, triclosan and zinc ions on dental plaque.
• Giertsen, Elin (1996). Effects of chlorhexidine, triclosan and zinc ions on dental plaque.
• Giertsen, Elin (1996). Effects of fluoride and xylitol on dental plaque and saliva.
• Giertsen, Elin (1996). Effekt av xylitol og fluorid på glykolytisk aktivitet i plakk. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  106(12), s 575- 575.
• Giertsen, Elin (1996). Håndhygiene i tannlegepraksis. Anbefalinger fra European Panel for Infection Control in Dentistry. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  106, s 174- 177.
• Giertsen, Elin (1996). Plakkhemmende stoffer – er de effektive?.
• Giertsen, Elin (1996, 01. oktober). Tannkrem mot sår i munnen.  Allers, HELSE & medisin, nr. 10, s. 85.
• Giertsen, Elin (1996). Xylitol - spesiell betydning i kariesprofylaksen?.
• Giertsen, Elin (1995). Effekter av xylitol og fluorid på plakkdannelse, gingivitt og salivær mikroflora. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  105(5), s 272- 272.
• Giertsen, Elin & Scheie, AAa (1995). Effects of fluoride, chlorhexidine and zinc ions on dental plaque. Journal of Dental Research.  ISSN 0022-0345.  74: Spec Iss: Abstract 518, s. 76(AADR/CADR, San Antonio, Texas, USA, mars 1995)
• Emberland, Hege; Giertsen, Elin & Scheie, AAa (1994). Effects of xylitol/fluoride on plaque acidogenicity and salivary flow rate.
• Giertsen, Elin; Scheie, AAa & Emberland, H (1994). Effects of xylitol and fluoride on dental plaque formation, gingivitis and salivary microflora. Caries Research.  ISSN 0008-6568.  28: Abstract 58, s. 197(ORCA, Cork, Irland, 29.06-02.07 1994)
• Arneberg, Pål; Giertsen, Elin; Emberland, H & Øgaard, B (1994). Total fluoride and pH in local plaque environments.
• Giertsen, Elin (1994). Bakteriedrepende og/eller syrehemmende effekter av klorheksidin munnskylling på tannplakk?. Den norske tannlegeforenings tidende.  ISSN 0029-2303.  104(5), s 198- 199.
• Giertsen, Elin (1994). Foredrag: Egne erfaringer med veiledere i Oslo og i Rochester. Seminaret "Dr. odont. og veilederfunksjonen i den organiserte forskerutdanningen" for stipendiater og veiledere ved Det odontologiske fakultet, UiO. Lysebu, Oslo, Norge.
• Giertsen, Elin & Scheie, AAa (1993). Bactericidal versus antiglycolytic effects of chlorhexidine mouthrinse on dental plaque.
• Giertsen, Elin & Scheie, AAa (1993). Effects of fluoride and zinc ions on acid formation by dental plaque. Caries Research.  ISSN 0008-6568.  27: Abstract 115, s. 239(ORCA, Dresden, Tyskland, juli 1993)
• Kari, S; Levomæki, R; Scheie, AAa & Giertsen, Elin (1993). Plaque pH response, acid profile, and bacterial counts at various areas.
• Giertsen, Elin & Scheie, AAa (1992). Effects of fluoride, triclosan, zinc, and Gantrez on plaque acidogenicity. Journal of Dental Research.  ISSN 0022-0345.  71: Spec Iss: Abstract 339, s. 148(AADR, Boston, Massachusetts, USA, mars 1992)
• Giertsen, Elin & Scheie, AAa (1992). Effects of fluoride, zinc, and chlorhexidine on plaque acidogenicity in vivo.
• Giertsen, Elin & Scheie, AAa (1992). Inhibitory effects of triclosan and SLS against mutans streptococci. Journal of Dental Research.  ISSN 0022-0345.  71: Spec Iss: Abstract 1278, s. 675(IADR, Glasgow, Skottland, juli 1992)
• Giertsen, Elin; Scheie, AAa & Evensen, JF (1992). In vivo effects of NaF-zinc and NaF-chlorhexidine on plaque acidogenicity in subjects with irradiation-induced hyposalivation. Caries Research.  ISSN 0008-6568.  26: Abstract 7, s. 210-211(ORCA, Helsinki, Finland, juni 1992)
• Scheie, Anne Aamdal; Giertsen, Elin & Evensen, Jens F (1992). Effekter av NaF-sink og NaF-klorheksidin på syreproduksjon i dentalt plakk og antall mutans streptokokker i saliva hos munntørre pasienter.

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