A new study shows the glow from tooth whitening often fades within a year, but whether you still love your smile may depend more on your personality than the shade of your teeth.
Study: Effect of personality characteristics on perception of tooth whitening outcome in young adults in long-term: a randomised, double-blind, placebo controlled trial. Image credit: PeopleImages.com - Yuri A/Shutterstock.com
Tooth whitening is a common practice, but its effectiveness over the long term remains unclear. Similarly, its impact on psychological and social health is poorly understood. A study published in Head & Face Medicine examined these aspects of tooth whitening over one year to assess how specific personality traits affected the outcomes.
Introduction
People often feel dissatisfied with tooth color, which inhibits their willingness to smile. Such attitudes are influenced heavily by culture, demographic profile, age- and sex-related factors, and even education.
Dentists often use standardized shade guides to assess tooth color, but this may not always provide satisfactory results. Spectrophotometry is a more objective and more reproducible instrument-based method of tooth color perception. The CIE Lab color space quantifies color by implementing lightness, red-green, and yellow-blue color axes. This system has been validated and aligns with the human eye's perception.
There is no demonstrated direct relationship between a more cosmetically appealing smile and quality of life. However, personality factors such as neuroticism, conscientiousness, and perfectionism may be more important in determining one's satisfaction with one's smile. In this context, the current study also considered how personality traits might alter the perceived effects of whitening, independent of the actual degree of color change achieved.
About the study
The study included 50 participants between 19 and 28 years old, randomized to either an intervention or a control group. The former received a light-activated whitening gel, while the latter received an inactive gel.
The participants were evaluated for tooth color, personality traits, and the intervention's psychosocial impacts at three time points: baseline, one week after treatment, and one year after treatment.
Study findings
Both intervention and control groups were similar in age distribution, sex ratio, quality of life, spectrum of personality traits, lightness, and translucency. However, the control group had significantly lower chroma (color saturation) at baseline (p=0.001). Notably, high lightness and low chroma predict satisfaction with how one’s smile looks.
The group exposed to the whitening gel showed improved tooth color one week after treatment compared to controls. The degree of whitening decreased over time, but even at one year, it was above the baseline.
Chroma decreased in the intervention group over the first week but increased one year after the intervention. The final chroma value remained lower than at baseline. Translucency went down over both the short- and long-term.
The control group showed no difference in either lightness or chroma after one week, but it decreased over one year. Translucency increased over the first week after intervention but declined over the first year thereafter. Thus, the short-term change in color was greater in the intervention group vs the control group. However, the difference between them tapered over the long term.
One week after the intervention, the whitening group significantly reduced psychological and social concerns but did not statistically significantly improve aesthetic concerns or dental self-confidence. This could reflect unrealistic expectations, the initial discomfort, or the need to get used to the change in tooth color. The intervention group did not feel that their teeth looked much better, nor did they feel more self-confident about their teeth. This might be because the difference in tooth color did not match the patient's high expectations. In comparison, controls reported a significant psychological improvement, which persisted over the long term.
At one year, the intervention group was more distressed as they perceived a relapse of their tooth discoloration, especially in participants with a detectable relapse (ΔE ≥ 3). The perceived relapse could have increased psychological stress in this group over time. In contrast, psychological improvement continued in the control group after this time.
“Preserving tooth color and addressing expectations and adaptation issues are crucial for optimizing psychological outcomes of dental aesthetic procedures.”
When stratified by personality traits, the investigators found that people who were more perfectionistic and less neurotic experienced more benefits one week after whitening. Less neurotic individuals were more satisfied with the effects of the whitening gel, in both groups.
Highly perfectionistic people were more likely to feel more socially comfortable after teeth whitening, as they are more conscious of improving their self-perceived formerly undesirable condition. Conversely, more conscientious individuals continued to experience more improvements over the long term. These effects were equally strong in both the whitening and placebo groups, indicating that personality influenced psychosocial outcomes regardless of the actual whitening achieved.
Personality traits affect psychosocial health more than the actual amount of tooth whitening achieved. People who show less responsible attitudes are more likely to act impulsively and may feel less burdened by the appearance of their smiles, thus improvements due to tooth whitening are less likely to benefit them psychosocially.
Conclusions
In this study, participants could not accurately assess the improvements in their tooth color after a tooth-whitening intervention. They often perceived a relapse to the discolored state over time. A strong placebo effect was seen, with participants in the control group showing satisfaction with the color change.
Personality traits played a powerful role in the procedure's impact on patients' psychosocial outcomes. Inter-group differences in psychosocial scores were not statistically significant overall, likely due to the high variability in individual responses. This indicates the need to adopt a personalized approach to cosmetic dental treatments, including individualized counseling, to ensure patient expectations are realistic and that patients are satisfied with the treatment provided.
The authors also noted study limitations, including the small sample size, focus on a single tooth, potential dehydration effects on enamel leading to temporary lightness changes, and technical challenges in repeat color measurements.
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