Prevalence

It has been reported that 8 to 30% of adults are affected by hypersensitivity.17 However, a large study of more than 3,500 subjects with gingival recession revealed only a 3.8% prevalence.18 Part of the variability in findings results from data collection discrepancies. Three studies in Scotland,17 Sweden,19 and Brazil20 that used self-reporting found 28%, 22%, and 25% of subjects described discomfort to daily life stimuli, respectively. When validated clinically, the prevalence was reported at only 14 to 18%.17,21 Outcomes are dependent upon whether such data are gathered by subject report or by clinical examination or a combination of both.

Rates of tooth sensitivity among clients in periodontal practices have been reported as higher than among the general dental population.4 The prevalence has been reported at 72 to 98% in periodontal patients compared to 3.8 to 57% in other populations.22 Presumably this is due to the greater incidence of root exposure and accompanying loss of tooth structure resulting from periodontal disease and therapy.

Females have been reported to have a higher incidence of hypersensitivity than males, although the difference is not statistically significant.17,20 The reported difference may be an artifact of the sampling methods used. Also, women may experience and report pain differently than men.23

With respect to the prevalence of hypersensitivity related to age, reports vary. The greatest incidence has been documented in the 20 to 40 year-old group, peaking in the third decade of life.17,20 This parallels the age group most affected by periodontal disease, with associated gingival recession and loss of enamel and cementum.

The impact of aging on hypersensitivity prevalence is unclear. With the average human lifespan at 76.9 years, and more people keeping their teeth longer, it can be assumed that clinicians will see more people with hypersensitivity in their practices. This is based on the observation that gingival recession, and concomitant loss of enamel and cementum, is more prevalent in older people.24 However, the paradox is that the incidence of hypersensitivity decreases after the fourth and fifth decades of life.2 This may be explained by the decrease in dentin permeability and neural response that takes place with age. These changes occur from the natural desensitization process of sclerosis and secondary dentin deposition. Long-term use of a fluoride dentifrice can also add to the desensitization process as the abrasive particles can occlude the dentin tubule openings and the mineralizing capacity of fluoride can decrease the diameter of the tubules.

Variability is reported in the distribution among specific teeth or teeth types that are most affected by hypersensitivity. The research is not conclusive as to the specific teeth and types of teeth that are affected by hypersensitivity. There is agreement that the buccal or facial surfaces are more affected by both recession and sensitivity than are the lingual surfaces. Upper premolars have been identified as the teeth that are the most affected, followed by upper first molars and incisors.18 The reported variation among tooth types may be the result of the use of different eliciting stimuli. In addition, it has been shown that heavyhanded brushing leads to more sensitivity on the opposite side.27 For example, a right handed brusher would likely have more sensitive teeth on the left side of the mouth.