Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
# 41486 Bacterial Adhesion on Integrated Abutment Crowns TM. In Vitro Study (I) ABSTRACT. Objectives: The goal of the present investigation was to determine if the Diamond-crown material, used to make Bicon's Integrated Abutment Crown (IAC), is less susceptible to harbor/attract bacterial plaque than All Ceramic (AC) or Metal Ceramic (MC) crowns. A secondary goal was to compare the composition of the plaque attracted on tested surfaces. Methods: 6 IAC, 6 AC and 6 MC crowns were equally divided in 2 test groups. The AC and MC crowns were cemented on titanium abutments. Group I (3 IAC,3 AC, 3 MC)and group II were incubated for 10 min in a bacterial solution containing 10 different oral bacteria at O.D.1: Tanerella forsythensis, Prevotella intermedia, Campylobacter rectus, Fusobacterium nucleatum, Actinomyces odontololyticus, A. naeslundii, Streptococcus intermedius, S. oralis, Actinobacillus actinomycetemcomitans serotype b, Porphyromonas gingivalis. After a brief wash in PBS to eliminate the unbound plaque, the crown samples in group I were incubated in 500µl of Tris-EDTA buffer with 500µl of NaOH. The samples were then hybridized with 10 whole chromosomal probes to the above mentioned microorganisms. The microbiological analysis was completed using the checkerboard DNA-DNA hybridization method. The samples in group II were briefly washed in PBS and fixed in 4% formalin for scanning electron microscopy (SEM) Results: All experimental crowns showed bacterial adhesion. There was no statistical difference in the microbial compositions when comparing crowns. The SEM showed that the AC crowns were harboring the heaviest bacterial deposits. MC and IAC showed the least bacterial deposits especially at the abutment/crown interface. Conclusions: The IAC and MC crowns appear to be less prone to bacterial colonization, in an in vitro setting then an all ceramic crown. IAC and MC crowns harbored very few bacteria at the abutment/crown interface This study was supported by a research grant from Bicon, Inc. 1 DIBART , 2 MARINCOLA , 1 WARBINGTON , 3 SKOBE S. M. M.L. and Z. 1 Boston University, MA, USA, 2 University of Cartagena, AISI, Italian Association of Restorative 3 Implant Dentistry, Rome, Italy, Forsyth Institute, Boston, MA INTRODUCTION The trauma surrounding the partial or total loss of the natural dentition to periodontal diseases or caries has been alleviated in the last decades by the introduction of the concept of predictable osseointegration to the dental profession 1,2. Successfully osseointegrated dental implants have revolutionized the practice of late 20th century dentistry. They provided patients with the ability to have fixed restorations instead of removable devices, and help avoid the mutilation of adjacent natural teeth when a 3 unit fixed partial restoration was envisioned. As with all prosthetic restorations in the oral cavity, they are subject to factors impacting esthetics, function, and periodontal health. Periodontal health or peri-implant health is the most critical aspect of this trilogy, since compromising it could mean potentially disastrous effects on esthetics and function. The tissues supporting dental implants are susceptible to disease (peri-implantitis), which in turn could lead to bone loss and implant failure. The disease process is initiated by microorganisms that are present in the periodontal plaque. These bacteria and their byproducts (enzymes, toxins, metabolic products), in the susceptible host, will start a whole cascade of events that will lead to periodontal tissue damage. bacteria need to adhere to a solid surface (i.e. prosthetic or natural crown, soft tissue etc.) in their primary phase of colonization before causing the disease. A restoration material that would repel or cause bacteria to adhere minimally would be a plus in preventing disease. In June 2001, Bicon Inc. (Boston, MA) introduced the Integrated Abutment Crown ™ (IAC). This is a new concept where the implant abutment and the crown material are one integral unit (Fig.1). A poly-ceramic material such as Diamond Crown ™ (DRM Research Labs Inc., Branford, CT) is fused onto the coronal post of a titanium alloy abutment. The IAC is then placed directly into the well of the implant, there is no need for cementation or screw A retention. The goal of the present investigation was to determine if the Diamond Crown™ material used to make Bicon’s IAC is less susceptible to harbor/attract bacterial plaque than All Ceramic (AC) or Porcelain Fused to Metal (PFM) crowns. RESULTS METHODS Figure 3. Scanning electron micrograph of a Porcelain fused to metal crown. Top of the micrograph shows crown abutment junction, with cement closing the gap. Lower half of the micrograph shows the porcelain margin at high magnification, with very few or no bacteria present. In the in vitro phase we tested bacterial presence and composition comparing the Integrated Abutment Crown to All Ceramic (porcelain Noritake Cerabien, Noritake Co., Nagoya, Japan) and Porcelain Fused to Metal (Noritake Super Porcelain EX-3, Noritake Co., Nagoya, Japan) crowns in a laboratory setting. The All Ceramic and the Porcelain Fused to Metal crowns were cemented on the abutments using Fuji Plus cement (GC Corporation, Tokyo, Japan). A total of 18 crowns were analyzed for bacterial presence/adhesion. All the crowns were provided by the Bicon corporation for our testing. The 18 crowns were divided in 2 groups. Group 1 which underwent microbiological analysis and group 2 which underwent SEM analysis. These groups were further subdivided in 1A (3 IAC), 1B (3 All Ceramic Crowns), 1C (3 Porcelain Fused to Metal Crowns) and 2A, 2B, 2C. The 9 crowns of group 1 were incubated for 10 minutes in a 100 ml PBS solution containing 10 oral bacteria at optical density of 1: Tannerella forsythensis, Prevotella intermedia, Campylobacter rectus, Fusobacterium nucleatum, Actynomyces odontolyticus, A. naeslundii, Streptococcus intermedius, S. oralis, Actinobacillus actinomycetemcomitans serotype b, Porphyromonas gingivalis. The crowns were immersed in a beaker containing the bacterial solution, with a stir bar. The crowns were removed and rinsed in sterile PBS for 30 seconds and put in a 15 ml tube containing 0.5 ml of TE (10 mM Tris-HCl, 1 mM EDTA, pH 7, 6). The bacterial DNA was denatured by adding 0.5 ml of a 0.5M solution of NaOH. The samples were then hybridized with 10 whole chromosomal DNA probes to these microorganisms according to the protocol described by Socransky et al. The 9 crowns of group 2 were also incubated for 10 minutes in the above mentioned bacterial mixture and rinsed in sterile PBS for 30 seconds. They were then fixed in 4% formalin at room temperature overnight, metal coated and prepared for scanning electron microscopy. Figure 2. Scanning electron micrograph of an all ceramic crownabutment junction. Notice the gap and lack of cement between prosthesis (top) and implant abutment (bottom). Figure 1. Clinical photograph of a Bicon Integrated Abutment Crown. The porcelain is fused to the abutment, there is no cementation. Figure 4. Scanning electron micrograph of an Integrated Abutment Crown. Top half of the micrograph shows crown-abutment interface, with no gap. Lower half of the micrograph shows the crown margin at high magnification, with very few or no bacteria present. All experimental crowns (IAC, AC, PFM) showed bacterial adhesion. All 10 bacterial species were found to adhere to each individual crowns. There was no statistical difference in the microbial composition found on the crowns investigated. This is probably due to the small size of the sample that did not show any statistically significant changes. The SEM analysis showed a clear difference in terms of amount and location of the microorganisms on the various crowns. All ceramic (AC) crowns harbored the heaviest bacterial deposits (Fig 2) and this was true for all areas studied, from occlusal surface to crown margins. Also more than one type of microorganism could be differentiated morphologically. This was confirmed by the microbiological analysis of the samples, all of the 10 microbial species could be detected using DNA probes (data not shown). At the abutment/crown interface a lack of cement was noticed as well as porosity in the ceramic structures (Fig 4). Many bacterial colonies were noticed in that area including in the micro-gap. Bacteria were also present, albeit at a much lower number, on porcelain fused to metal (PFM) and integrated abutment crowns (IAC). Bacterial colonization was also distributed differently. A few clusters of bacteria were present on the occlusal third of the IAC and extremely few on the PFM. Of much interest was the observations carried out at the crown margins (PFM) and abutment/crown interface (IAC). There were very few microorganisms observed at the abutment/crown interface for PFM and IAC. These 2 entities appeared to show the least amount of bacterial deposits (Figs. 3 and 4). CONCLUSION The results of this in vitro study seem to show that bacterial presence is inevitable on any type of prosthetic restoration. However the IAC design seems to go toward reducing this eventuality by eliminating the gap between implant abutment and crown, and providing a smooth cervical interface.