Therefore a proper topographical description should also include lateral and hybrid parameters. However, these provide only a description of vertical measurements, height and depth of the peaks and valleys, but lack information about their distribution. The arithmetical mean roughness, Sa (Ra in profile), and the root mean square roughness, Sq (Rq in profile), are the most used amplitude parameters. Topography can be characterized by a set of parameters that give information about height and distribution of the features on the surface. On the other hand, eukaryotic cells, like gingival fibroblasts possess a very elastic and flexible external membrane prone to accommodate to complex surface topographies and allow up to 100 μm cytoplasm spreading. Bacterial membrane rigidity may hinder their interaction with complex topographies, especially on nano-sized topographies on which the bacterial size exceeds the size of the accessible adhesion cavities. In both cases, and specifically for colonizers on both hard and soft tissues in the oral cavity, the total diameter is around 1 μm. More especifically, bacteria membranes are rigid and can be formed either by a thick external peptidoglycan layer, which defines a Gram-positive bacteria type or by a thin peptidoglycan layer covered by polysaccharides, which defines a Gram-negative type. Differences in topography are sensitive to the different sizes and external membrane compositions of these cells. Implant surface topography has historically been in the spotlight since it is known to modulate a differential response to bacterial and mammalian or eukaryotic cells. Therefore, the challenge persists in the design of implants with not only sufficient mechanical and integrative capacities, but also resistant to bacterial infections. To cause infection, bacteria must first colonise and then be retained at the implant site. Very often, the failures are linked to the development of infections of bacterial origin at the implant surfaces that run out of the control of clinicians. Statistics on dental implants show that success rate declines over time, especially in the presence of specific systemic conditions. Besides recovering aesthetics and masticatory functions, oral reconstructions are often associated with general health improvements, but unfortunately not all reconstructions succeed. Introductionĭental implantology allows immediate replacement of failing teeth. The results confirm that even though not all the measured surface is available for bacteria to adhere, the overall race for the surface between cells and bacteria is more favourable to the smoother surfaces (nitrided, as machined or lightly acid etched) than to the rougher ones (strong acid etched or sandblasted/acid etched).
Primary human oral gingival fibroblast (gum cells) and the bacterial strains: Streptococcus mutans, Streptococcus sanguinis and Aggregatibacter actinomycetemcomitans, implicated in infectious processes in the oral/implant environment were employed in the presence or absence of human saliva. In this work we have extended the topographical measurements also to lateral and hybrid parameters of the five most representative implant and prosthetic component surfaces and correlated the results with bacterial and mammalian cell adhesion and proliferation outcomes. Surface topography is known to modulate a differential response to bacterial and mammalian cells but topographical measurements are often limited to vertical parameters. Unfortunately not all reconstructions succeed, as a consequence of the development of infections of bacterial origin on the implant surface.
Dental implantology allows replacement of failing teeth providing the patient with a general improvement of health.