Is whitening right for me? - A guide to case selection
Teeth whitening is one of the most popular cosmetic dental treatments — and when done on the right candidate, the results can be truly transformative. But whitening is not a one-size-fits-all solution, and understanding whether you are a suitable candidate is an important first step. Here's an honest guide to help you understand what to expect.
Why does tooth colour vary in the first place?
Before we talk about whitening, it helps to understand why teeth become discoloured. There are two main types of tooth discolouration:
Extrinsic staining — staining on the outer surface of the tooth caused by external factors such as food, drink, and lifestyle habits. This type of staining responds well to whitening.
Intrinsic discolouration — colour changes that originate from within the tooth structure itself. This type is more complex and may not respond to whitening alone — or may require a different treatment approach altogether.
As we get older, the outer enamel layer thins and the inner dentine — which is naturally more yellow — becomes more visible
Who is a good candidate for whitening?
You are likely a good candidate for whitening if you have:
Healthy teeth and gums — whitening should only be carried out on a healthy mouth. Any cavities, gum disease, or outstanding dental issues should be addressed first
Realistic expectations about the outcome — whitening enhances your natural tooth colour, it does not produce an unnaturally bright result
Who may not be suitable for whitening — or requires special consideration?
Discoloured restorations Whitening gel works on natural tooth structure only — it has no effect on crowns, veneers, composite fillings, or any other dental restorations. If you have visible restorations on your front teeth, whitening your natural teeth may result in a colour mismatch between your whitened teeth and your existing restorations. These restorations would need to be replaced after whitening to match your new shade — and this should be factored into your treatment plan and budget from the outset.
Root canal treated teeth Teeth that have undergone root canal treatment can sometimes darken from the inside out — a type of intrinsic discolouration that external whitening gel cannot fully address. These teeth may benefit from a special technique called internal bleaching, where the whitening agent is placed inside the tooth itself. This is a separate procedure to standard whitening and requires assessment by your dentist.
Tetracycline staining Tetracycline is an antibiotic that, when taken during childhood while teeth are still developing, can cause a characteristic grey or brown banding discolouration within the tooth structure. This type of intrinsic staining is notoriously difficult to whiten and may not respond adequately to bleaching. More extensive cosmetic treatment such as veneers may be required to achieve a satisfactory result.
Fluorosis Fluorosis is a condition caused by excessive fluoride intake during tooth development, resulting in white spots, streaks, or in more severe cases, brown discolouration on the enamel. Whitening can sometimes help to blend mild fluorosis but may not fully resolve it — and in some cases can make white spots more noticeable initially before they blend. Careful assessment is important.
Sensitivity If you already experience sensitivity to hot, cold, or sweet foods, please inform your dentist before starting whitening. Whitening can temporarily increase tooth sensitivity — and patients who are already sensitive may find this more pronounced. This does not mean whitening is off the table — but your dentist may recommend a gentler protocol, a lower concentration gel, or a course of sensitivity treatment beforehand to make the process more comfortable.
Lifestyle habits Your habits have a significant impact on both the suitability and longevity of your whitening results:
Smokers — smoking is one of the most significant causes of tooth staining and will actively work against your whitening results. Whitening is still possible, but results will be less dramatic and will fade more quickly without addressing the habit
Heavy coffee, tea, and red wine drinkers — these are the most common dietary causes of staining. Whitening can still achieve good results, but ongoing consumption will cause the results to fade faster. Maintenance whitening will be needed more frequently
Diet high in acidic or staining foods — similarly, a diet high in pigmented or acidic foods will affect how long your results last
Important things to understand before whitening
Whitening results are not permanent This is one of the most important things to understand going into treatment. Whitening is not a one-time permanent solution — the effects will gradually fade over time, influenced by your diet, habits, and oral hygiene. Most patients find results last anywhere from 6 months to 2 years, after which top-up treatments may be needed to maintain the shade. This is completely normal and expected.
Wait before replacing restorations If you have restorations that need to be replaced to match your new whitened shade, it is important to wait at least 2 weeks after completing whitening before having them done. There are two reasons for this — firstly, the tooth shade continues to evolve and settle in the days after whitening and has not fully stabilised immediately after treatment. Secondly, the bonding of composite to freshly whitened teeth can be affected by residual whitening agents, potentially compromising the strength and colour match of the restoration. Waiting 2 weeks ensures a more accurate and durable result.
We always take a photograph and record your tooth shade before whitening — this gives us an objective baseline to compare against and helps document the change achieved. It also helps manage expectations going into treatment.
Understanding what whitening can realistically achieve.
We use the Vita Bleach (BL) shade guide to assess and document tooth colour. The BL scale runs from BL1 to BL4 — with BL4 being the most achievable shade through whitening alone, and BL1 representing the very whitest end of the scale.
It is important to understand that BL4 is realistically the whitest result that whitening can achieve for most patients — and even reaching BL4 depends on your starting shade and how well your teeth respond to the bleaching process. Results vary from person to person.
If you are hoping to achieve shades BL1, BL2, or BL3 — the very brightest, most Hollywood-white result — whitening alone is unlikely to get you there. Porcelain veneers are the more appropriate treatment to achieve those ultra-bright shades, as they allow your dentist to select the exact colour of the restoration. This is not a limitation of the whitening process — it is simply the nature of working with natural tooth structure, which has its own inherent properties and limits.
Being upfront about this from the start means you can make an informed decision about whether whitening or veneers — or a combination of both — is the right path for your smile goals.
💡Bottom line: Managing expectations is the most important part of any whitening consultation. Whitening is wonderful — but only if it works with your natural tooth structure, not against it. Understanding what it can and cannot achieve before you start means you will be far happier with the outcome. When in doubt, always ask!
