Why Is Surface Modification Needed?
The recent advances in implant dentistry have prompted dentists to consider multiple non-surgical strategies and preventive modalities post-implant insertion to maintain successful and long-term outcomes. It is not only the dental implant anchorage that affects the long-term success rates, but it is also the quality and surface of the dental implant that plays a crucial role in determining peri-implant (around the implanted area) health.
Not only the esthetic outcome but the prevention of connective tissue adhesion by promoting osseointegration (bone formation), anchorage (also called BIC - bone-implant contact), and preventing soft tissue inflammation; these biological and localized factors are responsible for both the success and failure of implants. However, technological advances in implant dentistry, like modifying titanium implant surfaces, are significant determinants of anchorage and stability.
What Is the Importance of Titanium Implant’s Surface Modification?
In the prosthetic implant system, the abutment that connects a fixture and the gingival component of the oral cavity creates the soft tissue seal. This seal protects the implanted area from bacterial contamination and, once formed, restores continuity in the anatomy and function of the tooth implanted that would have been disrupted while drilling the bone.
Research indicates that the titanium abutment geometry and surface significantly influence fibroblasts' marginal bone resorption and adhesion. It involves modifying the titanium abutment by specific methods that increase the surface roughness and the wettability of the implant. As per traditional implant research, a roughened implant surface promotes more epithelial adhesion and facilitates the creation of the soft tissue seal discussed above. The findings are credible in recent advances in surface modification of dental implants through the contact guidance concept.
What Is the Contact Guidance Concept?
The contact guidance concept states that compared to the two-dimensional nature of smooth implant surfaces, the roughened surfaces are bioactivated, remain three-dimensional, and can induce potent cell differentiation. In animal studies conducted by inserting implants according to the surface modification, four different kinds of methods have been compared as follows:
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Machined.
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Acid-etched.
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Surfaces that have been mildly oxidized.
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Machined with groove implants.
After six months of histologic study in detail in these animal studies, the machined implant surface possesses the smallest area of peri-implant tissue inflammation compared to the non-surface-modified areas or the grooved implants associated with larger inflammatory infiltrates in the peri-implant soft tissues.
What Are the Modification Methods?
Titanium material used for dental implants is known to have a stable form and good biological response without any capacity to trigger foreign body response in the host. However, research indicates that surface biocompatibility can be enhanced through micro roughened modifications. The different methods of surface modifications are listed below-
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Sand Blasted, Large Grit, Acid-Etched Surfaces (SLA) or Surface Roughened Implants: This method involves sandblasting the turned titanium surface of the implant with large grit particles ranging from 250 to 500 micrometers. Later, the surface is acid-etched with hydrochloric, sulfuric, or nitric acids. This method has been clinically shown to induce good osteogenesis and is the most frequently used surface modification in current-day implant dentistry.
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Anodic Oxidation: In the titanium layers of the dental implant, titanium oxide or TiO2 spontaneously forms when the implant surface is exposed to the atmosphere making it biocompatible in the oral cavity. This titanium oxide layer is not only thickened but also stabilized, and histomorphometric analysis has shown that there are lower rates of implant failure when the titanium surface is anodized.
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Hydroxyapatite-Coated Implants: The main component of the bone is the hydroxyapatite; research deems such an HA-coated particle layer to be biocompatible with the alveolar bone so that there is direct contact between osteoblast and coated surface. However, the major issue with such implant surfaces is that these HA particles may wear off; instead of promoting bone healing, they can provoke an Inflammatory host response, leading to the failure phenomenon of the implant in the load-bearing or the stress-bearing areas.
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Nano-Level Modification Methods: Other methods have been recently implemented in implant dentistry. The osteogenic cells can be programmed at a nanoscale level to be biocompatible with the implant's titanium surface. These methods include titanium dioxide nanotube arrangements, fluoride treatments, ultraviolet photofunctionalization, and coatings with functional peptides. These research methods are a developing area in the field of implant dentistry.
What Are the Types of Surface Treatments?
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Plasma Spray Coating: This technique involves depositing a thick layer of hydroxyapatite and titanium. Spraying is done with thermally melted materials on the implant, which helps increase its surface area.
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Grit Blasting Is a Technique for Roughening: The surface of the implant through pressurized particle projection using ceramic material or silica. This technique is used to embed surface contaminants on the implants.
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Acid Etching: In this technique, acids clean metal surfaces and alter their roughness. Acid-etched surfaces increase cell adhesion, bone formation, and, thereby, osseointegration.
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Sandblast, Large Grit, and Acid Etching (SLA): This technique induces surface erosion by applying strong acids to the blasted surfaces. It involves blasting with large grit particles and acid etching to obtain macro roughness and micro pits. It successively involves combinations of three procedures. This technique helps increase surface roughness and osseointegration. It was found that SLA-treated surfaces may be useful for improving tissue integration and cell proliferation.
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Other Methods: These include ion implantation, laser treatment, sputtering, and other combinations.
Conclusion:
To conclude, surface modification of dental implants is considered a significant advance in reducing any form of host inflammation or enhancing connective tissue formation so that the dental implants are osseointegrated and biocompatible. However, as it is a developing arena of implant dentistry, the ongoing research in surface modification of implant surfaces holds promising future results.