A professional dental cleaning can dramatically improve the appearance of your smile, but it does not technically whiten teeth in the way a chemical bleaching treatment does. The procedure is highly effective at restoring a tooth’s appearance to its natural color by removing built-up debris and discoloration. This mechanical removal often results in a brighter look. The distinction lies in the method: cleaning is mechanical, while true whitening requires a chemical reaction to change the tooth’s underlying shade.
The Cleaning Process and Its Effect on Brightness
A dental cleaning, or prophylaxis, focuses on mechanically removing foreign substances that have adhered to the tooth’s enamel over time. The process begins with the removal of plaque and tartar, also known as calculus, which is a hardened form of plaque that cannot be removed with a toothbrush. Tartar frequently has a yellowish or brownish hue, and its removal immediately reveals the natural tooth surface underneath.
The final step involves polishing the teeth using a high-powered rotary brush and a slightly abrasive paste. This action buffs away residual extrinsic stains caused by elements like coffee, tea, red wine, and tobacco. A smooth enamel surface reflects light more uniformly than a dull, stained surface, which creates the impression of a brighter smile. The improvement is a result of restoring the original surface rather than chemically altering the tooth structure.
Distinguishing Surface Stains from Intrinsic Tooth Color
A professional cleaning can only address extrinsic stains, which are discolorations on the outer surface of the enamel. These external stains are absorbed into the thin protein film and porous plaque or calculus. However, a tooth’s ultimate shade is determined by its intrinsic color, which lies deep within the tooth structure.
The outermost layer, enamel, is the hardest substance in the human body, but it is also semi-translucent. The color that shines through is primarily the shade of the dentin, the tissue layer beneath it. Dentin is naturally yellowish and makes up the bulk of the tooth structure. Intrinsic discoloration occurs when pigments become embedded within the dentin itself, often due to aging, medications like tetracycline, or trauma. As enamel naturally thins over decades of wear, more of the yellow dentin becomes visible, a change that no amount of mechanical cleaning can reverse.
Achieving True Chemical Whitening
To change a tooth’s intrinsic color, a chemical process is required to break down the colored molecules embedded in the dentin. This process is known as bleaching or whitening, and it uses active agents such as hydrogen peroxide or carbamide peroxide. These peroxide-based compounds penetrate the porous enamel layer to reach the underlying dentin.
Once inside, the peroxide breaks down into oxygen radicals, which initiate a chemical reaction called oxidation. This reaction targets the color-producing molecules, known as chromogens, converting them into smaller, lighter, or colorless compounds. This chemical alteration is the only method that can make a tooth genuinely lighter than its original shade. Many patients choose to have a cleaning before whitening, as removing surface debris allows the chemical agents to work more uniformly and effectively.