A Lesson from Toothbrushes

I think everyone ponders their toothbrush design from time to time.  Maybe not every time we brush our teeth but every once in awhile I’m confident the seconds or minutes brushing are filled with thoughts about the physical tool we are using and the very process we are performing.

For me, these thoughts reached a pinnacle in the 1990s. I watched more TV back then and thus saw many more advertisements than I do today. (This has been replaced with watching a little 5-second icon count down in the corner of my screen.) I remember that the commercials were replete with advertisements for the newest toothbrush design that would perform better, save time, or never need replacing, among many other claims.

For example, as a teenager, one advancement that struck me as obvious was the angled toothbrush head. It was touted as a way to brush the hard-to-reach back teeth. This seemed like a no-brainer and I was surprised at the time that not every toothbrush had that feature.

In my mind, this concept was improved upon by a flexible head that would still brush the hard-to-reach back teeth but become more straight for the front teeth where we might not want some obtuse angle in our toothbrush.

Source: Wikimedia

Another company chose to focus on the angle of the bristles to perform similar functions. I remember a toothbrush with elongated bristles at the top cutting down at a sharp triangular angle to the flat section of the brush. I still remember the now-archaic computer 3D models of this toothbrush moving and showing the viewer how this angled bristled brush would better contact the back of the front lower teeth with ease. Invariably, large dark pieces of plaque or other debris would be shown jettisoning off the teeth with even more ease – almost like magic.

The variation in bristle geometry seemed to explode after that. There were side bristles extending along the head that were a little taller than the other bristles claimed to brush the sides of a tooth better while brushing the top. There were angled bristle cuts to help the bristles get between the teeth like kind of like floss. There was a round circular section of bristles at the top that offered better cleaning when the user applied circular motion. Zig-zags, oval shapes, crenels and merlons, and many other variations were advertised. Even the coloring of some bristles were designed to fade over time telling the user to replace their toothbrush (with the same kind of brush as hoped by that company).

Source: DentalCare.ca

Next came the thickness of the bristles, with combinations of both stiff and flexible bristles which were claimed to be able to remove different types of debris stuck on your teeth.

The handle itself was not untouched. Longer handles, thicker handles, shaped handles, and cartoon character handles were all presented for bigger mouths, bigger hands, comfort, and for kids, respectively. I also remember a handle with a tooth picker at the opposite end. I had one of those. It was always poking my hand and cheek.

Source: Henry Schein Dental

As a teenager, I wanted all of these features and was amazed that there wasn’t a toothbrush that had, for example, a wide brush, with optimal bristle angles elongated in the corrected place, with bristles colored to fade over time, with an angled and flexible handle that was sized to my hand and had a pick and floss dispenser on the back, etc. Why couldn’t all the best features be combined into my toothbrush? This would be the optimal toothbrush, everyone would want one, and there would be no other design necessary.

It took more years of education to realize that my teenage toothbrush dream wasn’t really feasible.

First of all, the complexity for such a design would be through the roof. There would be many more elements to test and evaluate and of course more failure modes for the design. The combination of some of these features would likewise be non-compatible and cause some interactions that would invariably be detrimental, less effective, or impossible. Constraints on size, dimensions, and weight would limit what could be included on a single toothbrush. It might look ugly -- functional, yes-- but still ugly. We might not want to put it in our mouth if we’re older than 3-years old…

Second, the manufacturing would be painful and long. The number of steps in the manufacturing process would be doubled, tripled, or more. With the higher complexity, the manufacturing process might produce more failures for an overall lower yield and require a wider set of materials stored in inventory, in different hoppers, and in rolls throughout the factory floor taking up precious square footage. Precision manufacturing steps and specific training might also be necessary requiring advanced skills among the laborers.  

Third, based on the above two points, the cost would be way too high. How many of us are willing to spend more than 5 dollars or more on a single toothbrush that isn’t electric? Ultimately, the customer will be paying for the increased development efforts, the larger factory floor, and the increased rate and training for the technicians during the manufacturing processes. The profit margin would likely be set higher with a more complex product.

Source: Malidds.com

Fourth, we generally replace (or should replace) our toothbrushes regularly. Although there are some purchases we make once in our lives and keep for a long time, toothbrushes are not one of them. For those once-in-a-lifetime products, we spend time comparing and thinking and saving and exploring and…. A once-in-a-lifetime toothbrush, like the one I was envisioning as a teenager, is unlikely to exist. As a result, toothbrushes haven’t really changed much in 25 years and I’m using one that looks very similar to the one I used in 1995. I’ve experimented with an electric toothbrush that sits in my drawer unused, and I’m aware of more recent UV or sonic cleaning with full-mouth brushes, but it’s hard to beat the classic “stick with a simple brush on the one end.” Regardless, I project, at least right now, that I’ll be using the same type of toothbrush until the day I die.

I’m confident that companies have performed their due diligence with respect to novel toothbrush concepts and with focus groups, surveys, and other techniques have acquired the needs of the customer with respect to functions, features, cost, and use. The historical evidence suggests that for many years we have wanted something that is simple, inexpensive, and functional. Nothing more.

In our own design activities, if we want our own products to last for decades, we should look to the toothbrush for guidance. Keep it simple, inexpensive, and functional. Nothing more.