To view the SLA procedures, Al2
is widely used as sandblasting particles for surface cleaning or developing roughness. These particles, which were entrapped in the Ti surface, were difficult to remove through a popular used single acid-etching process. Moreover, this has been proved that can cause poor osseointegration, and a high density of Al ions on the Ti alloy may be related to Alzheimer's disease [20
]. Fortunately these particles can be replaced by a secondary sandblasting technique, which has a smaller particle size distribution than Al2
After placement of the dental implant, the complications of infection and fibrous encapsulation may occur during the healing process. The success of dental implants cannot merely be defined by the efficacy of osseointegration between the bone and the implant. Rather, a proper biological interaction to obtain healthy gingiva is essential as shown in . Among both of these contact parts between the tissues and the implant, epithelium linking would lead to the absence of inflammation [14
]. The integration of soft tissue provides a beneficial strategy where the epithelium linking is enhanced while the contact part of the gingival connective tissues is suppressed.
Unlike the case with their early stage adhesive and proliferative behavior, the XB-2 and 3T3 cells acted differently than each other in respect to their reaction to surface roughness. Based on the analysis in Figures and , 3T3 cells cultured on the smooth surface of the control group after 1
h were not significantly different from the largest roughness SLA 60/30 testing group (). However, in the control group, after 24
h cultured, the 3T3 cells went largely beyond testing groups with rough surfaces and were a 2.7-fold increase in cell numbers at 1
h culturing. Contrary to the results obtained with the 3T3 cells, the XB-2 cells had a statistical significance in roughness after 1
h of culturing; the control group displayed the best cell adhesive ability. However, after the XB-2 cells were allowed to proliferate at early stage for 24
h, there were no significant differences between the control and test groups (P
> 0.05). This early stage result indicates that epithelial cells cultured on roughened surfaces have better proliferative abilities than those cultured on smooth surfaces. The proliferative rate of XB-2 cells increased 2.6-fold from 1
h to 24
h of culturing for the SLA 60/30 testing, though the control group showed no specific statistical change. XB-2 cell's qualities in the control group after 1
h culturing were better than those of the roughened surfaces, the proliferative properties after 24
h culturing were reversed.
Early stage cell abilities such as adhesion and proliferation to the substrates can vary according to surface topography, which in turn influences cytoskeletal components [19
]. Sandblasting was thought to induce stress on the surface, whereas acid etching was thought to release the resulting residual stresses. Several related experiments [16
] reported that surface conditions can affect different types of cell morphology, and this is referred to as cell-specific discrepancies [27
]. Surface characteristics have been shown to regulate how the different cells reach clinically appropriate proportions with respect to the implant. For example, one of the main challenges in implant treatment lies in achieving an esthetic appearance, involving a physiological outcome [28
]. For soft-tissue integration involving epithelium cells adhesion and proliferation, roughened topographies should be recommended, as they can increase linking and inhibit the risk of fibrous capsulation by connective tissues.
The ion effects are demonstrated in . The early stage cell proliferative ability in the extracted cultured medium was significantly increased (P
< 0.05) in E1 cells but decreased in 3T3 cells. However, when the ionic effect was combined with the effect of topography in the comparative SLA 10/30/TTCP group, the proliferative ability of E1 cells was shown to be significant lower (P
< 0.05) than in the SLA 10/30 group. The calcium and phosphate ions became incorporated into the apatite that formed in an intimate association with the organic component, leading to bone formation [31
]. showed the promoted E1 bone cell growth was largely due to the topography rather than the ions. The ion effect played a less important role than the roughness with respect to E1 cell proliferation. The existence of calcium phosphates in a thin film coating can play a mediatory role between implants and natural bone tissues, but such properties did not lead to clinical success [33
]. Rough surfaces enhanced the ability to act as essential factors for bone cell adhesion and proliferation. The contacting surfaces between implants and the soft tissues should be roughened and ions releasing from TTCP hydrolysis should also be commented. This study clearly confirms the hypothesis that roughness and ion effects would impact the initial implant stability by the early stage cell interactions. The results had demonstrated that TTCP as the ions releasing medium could be a potential application in bone regeneration and prevention of the fibrous encapsulation of implants.