A Wennerberg

Publications of A Wennerberg

• In situ analysis of multispecies biofilm formation on customized titanium surfaces.

  Authors: V Fröjd, L Chávez de Paz, M Andersson, A Wennerberg, J R Davies, G Svensäter

  Molecular oral microbiology. 08/2011; 26(4):241-52.

  Many studies to identify surfaces that enhance the incorporation of dental implants into bone and soft-tissue have been undertaken previously. However, to succeed in the clinical situation, anMany studies to identify surfaces that enhance the incorporation of dental implants into bone and soft-tissue have been undertaken previously. However, to succeed in the clinical situation, an implant surface must not support development of microbial biofilms with a pathogenic potential. As a first step in investigating this, we used two-species and three-species biofilm models with 16S ribosomal RNA fluorescence in situ hybridization and confocal laser scanning microscopy to examine the effect of surface characteristics on biofilm formation by species that can colonize titanium implants in vivo: Streptococcus sanguinis, Actinomyces naeslundii and Lactobacillus salivarius. Surfaces blasted with Al(2) O(3) (S(a) = 1.0-2.0 μm) showed a seven-fold higher bacterial adhesion after 2 h than turned surfaces (S(a) = 0.18 μm) whereas porous surfaces, generated by anodic oxidation (S(a) = 0.4 μm), showed four-fold greater adhesion than turned surfaces. Hence, increased roughness promoted adhesion, most likely through protection of bacteria from shear forces. Chemical modification of the blasted and oxidized surfaces by incorporation of Ca(2+) ions reduced adhesion compared with the corresponding non-modified surfaces. After 14 h, biofilm growth occurred in the three-species model but not in the two-species consortium (containing S. sanguinis and A. naeslundii only). The biofilm biovolume on all surfaces was similar, suggesting that the influence of surface characteristics on adhesion was compensated for by biofilm development.

• The effect of hydroxyapatite nanocrystals on early bone formation surrounding dental implants.

  Authors: L M Svanborg, M Hoffman, M Andersson, F Currie, P Kjellin, A Wennerberg

  International journal of oral and maxillofacial surgery. 11/2010; 40(3):308-15.

  The knowledge of how nanostructures might affect early bone healing and osseointegration is limited. The aim of this study was to investigate if nanometer thick coatings of hydroxyapatiteThe knowledge of how nanostructures might affect early bone healing and osseointegration is limited. The aim of this study was to investigate if nanometer thick coatings of hydroxyapatite nanocrystals applied on a moderately rough surface might enhance early bone healing on screw-shaped dental implants and to evaluate if the thickness of the coat influences healing. Sandblasted and acid etched titanium implants coated with two different thicknesses of hydroxyapatite (test implants) and sandblasted and acid etched titanium implants (control implants), were inserted in rabbit tibia. After a healing time of 2, 4 and 9 weeks, a removal torque analysis and a histological evaluation were performed. The results from the removal torque analysis showed a tendency for higher values for the double coated hydroxyapatite after 4 weeks and for both the coated surfaces after 9 weeks of healing. The histological evaluations indicated slightly more new bone formation with the coated implants compared with the control; the differences did not reach statistical significance. The present study could not support the importance of nanometer thick coatings of hydroxyapatite nanocrystals in early bone healing, at least not when applied on a blasted and etched surface and placed in a cortical bone.

• Current challenges in successful rehabilitation with oral implants.

  Authors: A Wennerberg, T Albrektsson

  Journal of oral rehabilitation. 10/2010; 38(4):286-94.

  Very high survival/success rates have been reported for implant treatment, irrespective of the prosthetic type of reconstruction, be those full arcs, partial dentures, combined tooth implants orVery high survival/success rates have been reported for implant treatment, irrespective of the prosthetic type of reconstruction, be those full arcs, partial dentures, combined tooth implants or single crowns. However, survival/success is commonly reported in simple Cumulative Survival/Success Rate (CSR) tables only that may overestimate the true clinical outcome; furthermore, future challenges to clinical success may originate from too rapid launching of untested novelties or recommendations to apply too bold clinical procedures, potential problems that are summarised in the present paper.

• Precipitation of calcium phosphate in the presence of albumin on titanium implants with four different possibly bioactive surface preparations. An in vitro study.

  Authors: V Stenport, P Kjellin, M Andersson, F Currie, Y T Sul, A Wennerberg, A Arvidsson

  Journal of materials science. Materials in medicine. 08/2008;

  The aim of the present study was to compare the nucleating behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model with the presence albumin. Titanium discs wereThe aim of the present study was to compare the nucleating behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model with the presence albumin. Titanium discs were blasted (B) and then prepared by alkali and heat treatment (AH), anodic oxidation (AO), fluoridation (F), or hydroxyapatite coating (HA). The discs were immersed in SBF with 4.5 mg/ml albumin for 3 days, 1, 2, 3 and 4 weeks and analysed with scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and X-ray photoelectron spectroscopy (XPS). Topographic surface characterisation was performed with a contact stylus profilometer. The results demonstrated that the bioactive surfaces initiated an enhanced calcium phosphate (CaP) formation and a more rapid increase of protein content was present on the bioactive surfaces compared to the blasted control surface. The observation was present on all bioactive surfaces. The fact that there was a difference between the bioactive surfaces and the blasted control surface with respect to precipitation of CaP and protein content on the surfaces support the fact that there may be biochemical advantages in vivo by using a bioactive surface.

• Increased bone contact to a calcium-incorporated oxidized commercially pure titanium implant: an in-vivo study in rabbits.

  Authors: V Fröjd, V Franke-Stenport, L Meirelles, A Wennerberg

  International journal of oral and maxillofacial surgery. 06/2008; 37(6):561-6.

  The aim of this study was to evaluate the bone response to an oxidized titanium implant (Ox) and a calcium-incorporated oxidized titanium implant (Ca). A blasted titanium implant (Bl) was used asThe aim of this study was to evaluate the bone response to an oxidized titanium implant (Ox) and a calcium-incorporated oxidized titanium implant (Ca). A blasted titanium implant (Bl) was used as control. The implants were topographically characterized using an optical interferometer and placed: one in each distal femoral metaphysis and two in each proximal tibial metaphysis in rabbits. The rabbits were killed 12 weeks after implant insertion, and the implants and their surrounding tissues were removed en bloc for histomorphometrical evaluations. Topographical evaluation revealed three different surfaces: average height deviation (S(a), microm) values for Ca:Ox:Bl implants were 0.3:0.6:0.9, developed surface area ratios (%) 17:44:31, number of summits per microm(2) 208:136:118, and core fluid retention index values 1.33:1.33:1.38. The mean percentages of bone contact to the implants placed in the tibia (Ca:Ox:Bl) were 47:30:34 and to the implants placed in the femur (Ca:Ox) 32:20. The mean percentages of surrounding bone area for the implants placed in the tibia were 40:47:37 and for the implants placed in the femur 43:46. A significant increase in bone contact was found for smooth (S(a) <0.5 microm) but more densely peaked calcium-incorporated oxidized implants when compared to slightly rougher (S(a)=0.5-1.0 microm) oxidized or blasted implants.

• An in vitro comparison of possibly bioactive titanium implant surfaces.

  Authors: A Göransson, A Arvidsson, F Currie, V Franke-Stenport, P Kjellin, K Mustafa, Y T Sul, A Wennerberg

  Journal of biomedical materials research. Part A. 05/2008;

  The aim of the study was to compare Ca and P formation (CaP) and subsequent bone cell response of a blasted and four different possibly bioactive commercially pure (cp) titanium surfaces; 1. FluorideThe aim of the study was to compare Ca and P formation (CaP) and subsequent bone cell response of a blasted and four different possibly bioactive commercially pure (cp) titanium surfaces; 1. Fluoride etched (Fluoride), 2. Alkali-heat treated (AH), 3. Magnesium ion incorporated anodized (TiMgO), and 4. Nano HA coated and heat treated (nano HA) in vitro. Furthermore, to evaluate the significance of the SBF formed CaP coat on bone cell response. The surfaces were characterized by Optical Interferometry, Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). CaP formation was evaluated after 12, 24 and 72 h in simulated body fluid (SBF). Primary human mandibular osteoblast-like cells were cultured on the various surfaces subjected to SBF for 72 h. Cellular attachment, differentiation (osteocalcin) and protein production (TGF-beta(1)) was evaluated after 3 h and 10 days respectively. Despite different morphological appearances, the roughness of the differently modified surfaces was similar. The possibly bioactive surfaces gave rise to an earlier CaP formation than the blasted surface, however, after 72 h the blasted surface demonstrated increased CaP formation compared to the possibly bioactive surfaces. Subsequent bone cell attachment was correlated to neither surface roughness nor the amount of formed CaP after SBF treatment. In contrast, osteocalcin and TGF-beta(1) production were largely correlated to the amount of CaP formed on the surfaces. However, bone response (cell attachment, osteocalcin and TGF-F production) on the blasted controls were similar or increased compared to the SBF treated fluoridated, AH and TiMgO surface. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.

• Implants and/or teeth: consensus statements and recommendations.

  Authors: K Gotfredsen, G E Carlsson, A Jokstad, K Arvidson Fyrberg, M Berge, B Bergendal, T Bergendal, J E Ellingsen, J Gunne, M Hofgren [......] T. Närhi, K Nilner, B Owall, B Pjetursson, E Saxegaard, S Schou, R Stokholm, B Thilander, C Tomasi, A Wennerberg

  Journal of oral rehabilitation. 02/2008; 35 Suppl 1:2-8.

  In August 23-25, 2007, the Scandinavian Society for Prosthetic Dentistry in collaboration with the Danish Society of Oral Implantology arranged a consensus conference on the topic 'Implants and/orIn August 23-25, 2007, the Scandinavian Society for Prosthetic Dentistry in collaboration with the Danish Society of Oral Implantology arranged a consensus conference on the topic 'Implants and/or teeth'. It was preceded by a workshop in which eight focused questions were raised and answered in eight review articles using a systematic approach. Twenty-eight academicians and clinicians discussed the eight review papers with the purpose to reach consensus on questions relevant for the topic. At the conference the consensus statements were presented as well as lectures based on the review articles. In this article the methods used at the consensus workshop are briefly described followed by the statements with comments.

• Improved bone ingrowth and fixation with a thin calcium phosphate coating intended for complete resorption.

  Authors: O Reigstad, V Franke-Stenport, C B Johansson, A Wennerberg, M Røkkum, A Reigstad

  Journal of biomedical materials research. Part B, Applied biomaterials. 11/2007; 83(1):9-15.

  Bonit is claimed to be a resorbable electrochemically deposited calcium phosphate coating consisting mainly of brushite, which is a hydroxyapatite precursor. This study involved a comparison ofBonit is claimed to be a resorbable electrochemically deposited calcium phosphate coating consisting mainly of brushite, which is a hydroxyapatite precursor. This study involved a comparison of Ti6Al4V screw-shaped implants with and without a 15 +/- 5 microm Bonit coating in rabbit tibia and femur, after 6 and 12 weeks of insertion. The biomechanical removal torque test showed significantly increased values for the coated implants after 12 weeks (p < 0.05) but not after 6 weeks of integration. Higher bone-implant contact was found for the coated implants in the tibia after 6 weeks and for both tibial and femoral screws after 12 weeks (p < 0.05). There was no difference in the inflammatory reaction around the implants, and possible grains of the coating could be detected after 6 weeks, but not after 12 weeks of follow-up. This unloaded short-term study has shown promising results for the easily applicable and resorbable coat (Bonit) compared to uncoated titanium-alloy implants.

• Inflammatory response to titanium surfaces with fibrinogen and catalase coatings: an in vitro study.

  Authors: A Göransson, C Gretzer, P Tengvall, A Wennerberg

  Journal of biomedical materials research. Part A. 04/2007; 80(3):693-9.

  The aim of the present study was to evaluate the possibility to modulate the early inflammatory response in vitro by coating titanium surfaces with candidate proinflammatory (fibrinogen coated turnedThe aim of the present study was to evaluate the possibility to modulate the early inflammatory response in vitro by coating titanium surfaces with candidate proinflammatory (fibrinogen coated turned titanium "Fib") and antiinflammatory proteins (catalase on top of fibrinogen coated turned titanium "Cat"). Additionally, turned titanium surfaces (Ti) were used as controls. The discs were incubated with human mononuclear cells. Adhered cells were investigated with respect to number, viability, differentiation (acute marker 27E10 vs. chronic marker RM3/1), and cytokine production (TNF-alpha and IL-10), after 24 and 72 h. The results indicated that it is possible to modulate the inflammatory response with protein coatings. However, the strongest inflammatory response, indicated by increased number of adhered cells and release of pro and antiinflammatory mediators, was induced by Cat. Furthermore, the cytokine production on this surface was not sensitive to LPS stimulation. Differentiation measured as the expression of the chronic cell surface marker, dominated after 72 h for all surface modifications and Cat displayed an increased number compared to the others. A decrease in the total number of adhered cells and amounts of TNF-alpha were observed on all surfaces over time. The cell viability was, in general, high for all tested surfaces. In conclusion, the study proved it possible to influence the early inflammatory response in vitro by immobilizing protein coatings to titanium surfaces. However, the catalase surface demonstrated the strongest inflammatory response, and the possibility to selectively use the potent antiinflammatory capacity of catalase needs to be further evaluated.

• Characterisation of structures in salivary secretion film formation. An experimental study with atomic force microscopy.

  Authors: A Arvidsson, C Diogo Löfgren, C E Christersson, P O Glantz, A Wennerberg

  Biofouling. 07/2004; 20(3):181-8.

  The purpose of the present study was to characterise the structure dynamics of pure salivary secretions retained on controlled surfaces with different surface energies in the early stage of salivaryThe purpose of the present study was to characterise the structure dynamics of pure salivary secretions retained on controlled surfaces with different surface energies in the early stage of salivary film formation. Germanium prisms prepared to have either low surface energy or medium surface energy were incubated in fresh secretions of either human parotid saliva (HPS) or human submandibular/sublingual saliva (HSMSLS) for 15, 90, and 180 min. After controlled rinsing with distilled water, the surfaces were air dried and thereafter imaged with atomic force microscopy (AFM). The amount of adsorbed material and the size of the structures detected increased with increased saliva exposure time. The film thicknesses varied from 10 to 150 nm, and both HPS and HSMSLS films contained structures with diameters varying from 40 nm to 2 microm. Some of these were clustered into special formations. The HPS films exhibited a more granular morphology than the HSMSLS films. Furthermore, branched lines were detected on the low surface energy germanium prisms incubated in saliva. The results indicate that exposure time, surface energy, and type of salivary secretion all are factors affecting the adsorption characteristics of salivary films.

• Biological behavior of sol-gel coated dental implants.

  Authors: P A Ramires, A Wennerberg, C B Johansson, F Cosentino, S Tundo, E Milella

  Journal of materials science. Materials in medicine. 07/2003; 14(6):539-45.

  The biocompatibility of dental implants coated with titania/hydroxyapatite (HA) and titania/bioactive glass (BG) composites obtained via sol-gel process was investigated using an in vitro and in vivoThe biocompatibility of dental implants coated with titania/hydroxyapatite (HA) and titania/bioactive glass (BG) composites obtained via sol-gel process was investigated using an in vitro and in vivo model. A device for the in vitro testing of screw-shaped dental implants was developed, in order to well compare the two experimental models studying the behavior of human MG63 osteoblast-like cells seeded onto a particular geometry. The expression of some biochemical parameters of osteoblastic phenotype (alkaline phosphatase specific activity, collagen and osteocalcin production) and some indications on cells morphology obtained by scanning electron microscopy were evaluated. The in vitro and in vivo models were compared after implants insertion in rabbit tibia and femur. The removal torque and histomorphometric parameters (percentage of bone in contact with implant surface and the amount of bone inside the threaded area) were examined. A good agreement was found between the in vitro and in vivo models. These experiments showed better performances of HA and BG sol-gel coated dental implants with respect to uncoated titanium; in particular, it was found that in vitro the HA coating stimulates osteoblastic cells in producing higher level of ALP and collagen, whereas in vivo this surface modification resulted in a higher removal torque and a larger bone-implant contact area. This behavior could be ascribed to the morphology and the chemical composition of the implants with rough and bioactive surfaces.

• Bone formation after 4 weeks around blood-plasma-modified titanium implants with varying surface topographies: an in vivo study.

  Authors: A Göransson, E Jansson, P Tengvall, A Wennerberg

  Biomaterials. 02/2003; 24(2):197-205.

  The aim of the present study was to investigate and compare the stability and bone ingrowth capacity to screw-shaped titanium implants with five different surface treatments. The implants were: (1)The aim of the present study was to investigate and compare the stability and bone ingrowth capacity to screw-shaped titanium implants with five different surface treatments. The implants were: (1) standard turned with a thin blood plasma coat (TP), (2) NaOH-etched dito with pore size 0.2-0.3 microm (E), (3) NaOH-etched with pore size 0.2-0.3 microm and a thin blood plasma coat (EP), (4) electrochemically oxidised with pore size 1-2 microm (O), (5) electrochemically oxidised with pore size 1-2 microm and a thin blood plasma coat (OP). A total of 66 implants were divided into the above-described five groups and inserted for 4 weeks into tibia and femur of 11 rabbits. The implants were evaluated by resonance frequency (RF) measurements at the time of insertion and removal, and analysed histomorphometrically at removal. The RF measurements showed that the implant stability was lower in soft bone compared to dense and increased with time. No significant differences were observed between the different surface modifications. The histomorphometric analysis revealed no statistically significant differences between the implants regarding bone-to-metal contact (BMC) and bone area inside the threads (BA). The above results indicate that thin blood plasma-coated and non-coated screw-shaped titanium implants with turned, NaOH-etched and electrochemically etched surface profiles integrate similarly to bone at 1 month of implantation.

• The mucosal attachment to titanium implants with different surface characteristics: an experimental study in dogs.

  Authors: I Abrahamsson, N U Zitzmann, T Berglundh, E Linder, A Wennerberg, J Lindhe

  Journal of clinical periodontology. 06/2002; 29(5):448-55.

  BACKGROUND: Findings from in vitro studies have indicated that the orientation and proliferation of cells on titanium surfaces may be influenced by the topography of the surface on which they areBACKGROUND: Findings from in vitro studies have indicated that the orientation and proliferation of cells on titanium surfaces may be influenced by the topography of the surface on which they are grown. It may be argued, therefore, that differences may occur in the mucosal attachment to titanium implants with different surface roughness. AIM: The present experiment was performed to study the composition of the soft tissue barrier that formed to implants prepared with well-defined smooth or rough surfaces. MATERIAL AND METHODS: Five beagle dogs were used. Four implants made of c.p. titanium were placed in the right edentulous mandibular premolar region. After 3 months, two different types of abutments were connected: one experimental (OA) with a dual, thermal acid-etched surface ('Osseotite'), and one regular (RA) abutment with a 'turned' surface. At the end of a 6-month period during which proper plaque control had been maintained, biopsies including the implant and the surrounding soft and hard tissues were obtained, decalcified and processed for light and electron microscopy. A confocal He-Ne laser profilometer was used to study the surface topography of the abutments. RESULTS: The attachment between the peri-implant mucosa and titanium abutments with either a turned (RA; 'smooth') or acid-etched (OA; 'rough') surface was similar from both a quantitative and a qualitative aspect. The attachment comprised a barrier epithelium and a zone of connective tissue attachment of similar dimension at RA and OA. It was further observed that the 'inner' zone of the connective tissue attachment at both types of abutment was composed of about 30-33% fibroblasts and 63-66% collagen. CONCLUSION: It was demonstrated that the soft tissue attachment that formed to implants made of c.p. titanium was not influenced by the roughness of the titanium surface.

• The importance of surface texture for bone integration of screw shaped implants: an in vivo study of implants patterned by photolithography.

  Authors: C Hallgren, H Reimers, J Gold, A Wennerberg

  Journal of biomedical materials research. 01/2002; 57(4):485-96.

  The aim of the present study was to investigate the influence of different properties inherent in surface topography on the integration of an implant in bone. Using a photolithography technique, aThe aim of the present study was to investigate the influence of different properties inherent in surface topography on the integration of an implant in bone. Using a photolithography technique, a specific surface pattern was produced on the screw flanks of threaded titanium oral implants. Surface topography was qualitatively assessed by scanning electron microscopy (SEM) and a confocal laser scanning profilometer. Quantitative analysis with the confocal laser profilometer derived parameters for surface roughness and surface roughness together with waviness. The chemical composition of the implant surfaces was analyzed by Auger electron spectroscopy. The patterned and control (turned) implants were inserted in New Zealand White rabbits with a healing period of 3 months. Bone fixation was evaluated with resonance frequency analysis (RFA), peak removal torque analysis (RTQ), and by histomorphometry. No statistically significant differences were seen in the fixation, with respect to bone-to-implant contact, between the patterned and control implants.

• Interventions for replacing missing teeth: different types of dental implants.

  Authors: M Esposito, P Coulthard, H V Worthington, A Jokstad, A Wennerberg

  Cochrane database of systematic reviews (Online). 01/2002;

  BACKGROUND: Dental implants are available in different materials, shapes and with different surface characteristics. In particular, numerous implant surface modifications have been developed forBACKGROUND: Dental implants are available in different materials, shapes and with different surface characteristics. In particular, numerous implant surface modifications have been developed for enhancing clinical performances. OBJECTIVES: To test the null hypothesis of no difference in clinical performance between various root-formed osseointegrated implant types. SEARCH STRATEGY: The Cochrane Oral Health Group Specialised Trials Register, The Cochrane Controlled Trials Register, MEDLINE and EMBASE were searched. Hand searching included several dental journals. Bibliographies of relevant clinical trials and review articles were checked for studies outside the handsearched journals. In addition, authors of all identified trials and fifty-five oral implant manufacturers were contacted to find unpublished or ongoing RCTs. Two extensive personal libraries (ME and AJ) were consulted. The last electronic search was conducted 8th May 2002. SELECTION CRITERIA: All randomised controlled trials of oral implants comparing implants with different materials, shapes and surface properties having a follow-up of at least one year. DATA COLLECTION AND ANALYSIS: Data were independently extracted, in duplicate, by two reviewers (ME & HW). Authors were contacted for details of randomisation and withdrawals and a quality assessment was carried out. The Cochrane Oral Health Group's statistical guidelines were followed. MAIN RESULTS: Thirty publications, representing 13 different RCTs, were identified. Five of these RCTs (seven publications), which reported results from a total of 326 patients, were suitable for inclusion in the review. Six implant systems were compared: Astra, Branemark, IMZ, ITI, Steri-Oss and Southern with a follow-up ranging from one to three years. All implants were made in commercially pure titanium and had different shapes and surface preparations. On a patient rather than per implant basis there were no statistically significant differences for failures and marginal bone level changes on intra-oral radiographs between various implant systems. REVIEWER'S CONCLUSIONS: There was no evidence that any of the implant systems evaluated was superior to the other. However, these findings are based on a few RCTs all having short follow-up periods and few participants. More RCTs should be conducted, with follow-up of at least five years and including a sufficient number of patients, to detect a true difference if any exists. Such trials should be reported according to the CONSORT guidelines (http://www.consort-statement.org/).

• Reactions in the oral mucous membrane after exposure to Carisolv--combined results from a clinical screening test in humans and an experimental study in rats.

  Authors: A Arvidsson, C Stirling, L Sennerby, A Wennerberg

  Gerodontology. 01/2002; 18(2):109-13.

  OBJECTIVE: To evaluate reactions in the oral mucosa after direct contact with Carisolv. SETTING: The Faculty of Odontology in Göteborg, Sweden. SUBJECTS: 34 healthy persons for a clinical screeningOBJECTIVE: To evaluate reactions in the oral mucosa after direct contact with Carisolv. SETTING: The Faculty of Odontology in Göteborg, Sweden. SUBJECTS: 34 healthy persons for a clinical screening test and 35 Sprague Dawley rats for a histological study. DESIGN: Mixed Carisolv or 0.5 % NaOCl were soaked in paper and applied to either side of the medial frenula of the lower lip of 34 persons. The solutions were left on the oral mucosa for three minutes. Inspection was made and photographs were taken immediately after exposure and also after 1 hour, 24 hours, and 72 hours. Mixed Carisolv was applied in a similar manner as described above to 35 adult Sprague Dawley rats. The animals were killed and biopsies were taken immediately after Carisolv exposure and also after 1 hour, 24 hours, and 48 hours. The biopsies were sectioned and prepared for histomorphometrical evaluation in light microscopy where cells were counted on regions from the epithelium layer deeper into the mucous membrane. RESULTS: Some adverse reactions were detected on the oral mucosa of humans up to 24 hours after Carisolv exposure for 3 minutes. The detected inflammatory reactions were slight and no patient felt any discomfort. The results of the histological study on rat did not show any statistically significant increase of the number of cells at any time after Carisolv exposure. CONCLUSIONS: If the oral mucosa gets in direct contact with Carisolv for 3 minutes no or only a weak inflammatory response may be expected.

• Protein characterisation of salivary and plasma biofilms formed in vitro on non-corroded and corroded dental ceramic materials.

  Authors: P Milleding, A Carlén, A Wennerberg, S Karlsson

  Biomaterials. 10/2001; 22(18):2545-55.

  Dental ceramics are generally regarded as low-adhesive materials. Different ceramics may, however, differ in composition and physico-chemical surface properties, which may be changed after corrosion.Dental ceramics are generally regarded as low-adhesive materials. Different ceramics may, however, differ in composition and physico-chemical surface properties, which may be changed after corrosion. The aim of this study was to examine the adsorption of proteins onto specimens of different ceramic materials after the incubation in saliva and plasma before and after in vitro corrosion. In addition, the topography of the biofilm was examined by AFM. Surface-bound proteins were desorbed and analysed by polyacrylamide gel electrophoresis (PAGE) and immunoblotting using antibodies to saliva and plasma proteins. Silver-stained gels indicated differences in the adsorption of proteins. Differences in surface roughness at the nanometer level did not, however, seem to be correlated to the protein adsorption. After corrosion, unchanged or increased protein staining was generally seen in the gels and Western blots. The reactions for salivary amylase and proline-rich proteins varied between the different materials. Albumin and fibrinogen were identified in samples from all materials tested. Fibronectin and in specific IgA were more sparsely seen. No saliva but all plasma proteins were identified in the alumina and yttria-stabilised zirconia samples and reduced protein reactions were obtained after corrosion.

• Determining optimal surface roughness of TiO(2) blasted titanium implant material for attachment, proliferation and differentiation of cells derived from human mandibular alveolar bone.

  Authors: K Mustafa, A Wennerberg, J Wroblewski, K Hultenby, B S Lopez, K Arvidson

  Clinical oral implants research. 10/2001; 12(5):515-25.

  In the complex process of bone formation at the implant-tissue interface, implant surface roughness is an important factor modulating osteoblastic function. In this study, primary cultures ofIn the complex process of bone formation at the implant-tissue interface, implant surface roughness is an important factor modulating osteoblastic function. In this study, primary cultures of osteoblast-like cells, derived from human mandibular bone, were used. The aim was to examine the effect of varying surface roughness of titanium implant material on cellular attachment, proliferation and differentiation. A recognized method of increasing surface roughness and enlarging the surface area of titanium implants is by blasting with titanium dioxide particles: the four specimen types in the study comprised surfaces which were machine-turned only, or blasted after turning, with 63-90 microm, 106-180 microm, or 180-300 microm TiO(2) particles, respectively. The specimens were analyzed by scanning electron microscopy and confocal laser scanning. The turned samples had the smoothest surfaces: average height deviation (S(a)) of 0.20 microm. The roughest were those blasted with 180-300 microm particles, S(a) value 1.38 microm. Blasting with intermediate particle sizes yielded S(a) values of 0.72 microm and 1.30 microm, respectively. Cell profile areas were measured using a semiautomatic interactive image analyzer. Figures were expressed as percentage of attachment. DNA synthesis was estimated by measuring the amount of [(3)H]-thymidine incorporation into trichloroacetic acid (TCA) insoluble cell precipitates. The specific activity of alkaline phosphatase was assayed using p-nitrophenylphosphate as a substrate. The ability of the cells to synthesize osteocalcin was investigated in serum-free culture medium using the ELSA-OST-NAT immunoradiometric kit. After 3 h of culture, the percentage of cellular attachment did not differ significantly between specimens blasted with 180-300 micromparticles and the turned specimens. All blasted surfaces showed significantly higher [(3)H]-thymidine incorporation than the turned surfaces (P<0.05), with the highest on the surfaces blasted with 180-300 microm particles. Osteocalcin synthesis by the cells in response to stimulation by 1,25(OH)2D3, was also significantly greater (P<0.05) on the surfaces blasted with TiO(2) particles. However, analysis of alkaline phosphatase activity disclosed no significant differences among the four surface modifications. It is concluded that in this cellular model, the proliferation and differentiation of cells derived from human mandibular bone is enhanced by surface roughness of the titanium implant. However, increasing the size of the blasting particles to 300 microm does not further increase the initial attachment of the cells compared to turned surfaces and those blasted with 63-90 microm particles.

• Cellular reactions and bone apposition to titanium surfaces with different surface roughness and oxide thickness cleaned by oxidation.

  Authors: S Kanagaraja, A Wennerberg, C Eriksson, H Nygren

  Biomaterials. 08/2001; 22(13):1809-18.

  Titanium surfaces with three different surface characteristics were exposed to an intraperitoneal milieu in mouse or rat, or inserted into rabbit bone. The cleaning regimen of the TiO2 surfaces inTitanium surfaces with three different surface characteristics were exposed to an intraperitoneal milieu in mouse or rat, or inserted into rabbit bone. The cleaning regimen of the TiO2 surfaces in this study included oxidation by heat or acid and a final rinsing and storage in water. Intraperitoneal exposure ranged from 1 to 64 min and the healing period in bone was 6 weeks. Cell recruitment to the surfaces was quantified by acridine orange staining and specific antibodies directed against cell membrane antigens. Removal torque, bone-to-metal contact, total bone area and histological evaluations were used to evaluate fixture stability and the healing-in of the implants. After the healing period of 6 weeks only a transient significant difference was seen in the total number of cells adherent on the surfaces. No significant differences were observed between any of the surfaces for removal torque, bone-to-metal contact, or bone area. The areas lacking bone-to-metal contact were filled with normal vascularised connective tissue with no signs of fibrous capsule formation or giant cells. These findings differ from findings published earlier of Ti implants that underwent a cleaning regimen with alcohol as the final rinsing step. The tissues around the implants were richly vascularised and there was continued bone growth toward the surfaces. The bone-to-metal contact in this study was lower than that seen with alcohol-cleaned TiO2.

• Histologic evaluation of the bone integration of TiO(2) blasted and turned titanium microimplants in humans.

  Authors: C J Ivanoff, C Hallgren, G Widmark, L Sennerby, A Wennerberg

  Clinical oral implants research. 05/2001; 12(2):128-34.

  Twenty-seven patients received 2 microimplants each during implant surgery. One microimplant was blasted with 25 microm sized particles of TiO(2); the other was left as machined i.e. a turnedTwenty-seven patients received 2 microimplants each during implant surgery. One microimplant was blasted with 25 microm sized particles of TiO(2); the other was left as machined i.e. a turned surface. Before insertion the surface topography was characterized with an optical confocal laser profilometer. The surface roughness was greater than standard implants, and was similar for both surface modifications averaging over all parts of the implant i.e. tops, valley and flanks. The mean surface roughness from flank measurements only replicated previously reported findings: i.e. significantly rougher surfaces on blasted implants. After a mean healing period of 6.3 months in the maxillae and 3.9 months in the mandible, the microimplants and surrounding tissue were removed with a trephine burr. The histomorphometrical evaluation demonstrated significantly higher bone-to-implant contact for the blasted implants, inserted in the maxilla or in the mandible. Significantly more bone was found inside the threaded area for the blasted implants in the mandible, but there was no difference for implants positioned in maxillae.