**Author details**

surfaces than on ceramic surfaces with well-organized focal contacts and pre-hemidesmo‐

Brunete and Chehroudi [62] in their review have suggested that the micro-fabricated grooved surfaces are able to inhibit epithelial downgrowth on implants depending on the dimension of the grooves in vitro. Similarly, fibroblasts also exhibit contact guidance on grooved surfaces, although its shape in vitro differs from that found in vivo. Delgado-Ruiz and co-workers [63] noted that micro-grooved surfaces were able to induce transverse collagen fibre formation, thus supporting two studies [26, 64]. It is also important to include a study by Nevins et al. [26] who demonstrated that soft tissue in humans is attached mechanically by perpendicular

Over the years, many strategies have been explored to improve the biological seal of periimplant tissue by changing the surface chemistry of dental implants and implant abutments. The surface chemistry of the materials may be altered by biological modification, or by changing the chemical composition of the materials. As for biological modifications, methods of surface modification available include adding or coating with biomimetic/bioactive substances such as fibronection or intergrin onto the surface with the aim of promoting cellular adhesion and controlling cell behaviour. Fibronectin is a glycoprotein present on cell surfaces, found in connective tissues, basement membranes, and extracellular fluids, and is known to play a role in cell-to-cell and cell-to-substrate adhesion and enhances gingival fibroblast attachment. It is interesting to note that epithelial cells and fibroblasts have different affinities for adhesive proteins of the extracellular matrix. Dean et al [65] noted that higher number of fibroblasts bound to fibronection coated implant surface than epithelial cells, while gingival epithelial cell binding on implant surface coated with laminin was higher in number than fibroblasts [66, 67]. Collagen Type 1 was also used to modify surface chemistry as it was found

The chemistry of material surfaces can also be altered by using element such as calcium or magnesium coating. Hydrothermal treatment of titanium with CaCl2 or MgCl2 was found to enhance initial attachment of epithelial and fibroblasts cells, and may increase the quality of the soft tissue seal around dental implant [69]. In addition, surface chemistry of materials may also inadvertently altered by the presence of impurities, surface contamination and saliva. A clean surface has a high surface free energy, while a contaminated one has a lower surface

There is some controversy on the possible attachment of connective tissue fibres to implant, but current studies indicate the presence of a parallel orientation with no insertion of periimplant connective tissue fibres. This difference in connective tissue attachment may affect the peri-implant tissue's susceptibility to disease. The gold standard for evaluating the connective

somes found on metallic surfaces, but not on porcelain and aluminium oxide.

collagen fibre bundles on a micro-grooved pulsed laser surface.

to improve initial fibroblasts attachment [68].

*4.2.2. Surface composition*

52 Dental Implantology and Biomaterial

energy.

**5. Conclusion**

Wen Lin Chai1 , Masfueh Razali2\* and Wei Cheong Ngeow3

\*Address all correspondence to: masfuah\_razali@yahoo.com

1 Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia

2 Department of Periodontology, Faculty of Dentistry, Universiti Kebangsaan Malaysia (UKM), Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia

3 Department of Oro-Maxillofacial Surgical & Medical Sciences, Faculty of Dentistry, Uni‐ versity of Malaya, Kuala Lumpur, Malaysia
