**2.3. Prevalence according to gender**

In the anterosuperior region, this stability is especially desired and verified by patients. Most of the publications on anterosuperior diastemas consist of clinical cases and reviews of the literature on the etiology of the problem and its possible treatments. But, there is a shortage in the literature of studies on the stability of the treatment of the upper interincisal subjects. The present chapter seeks to evaluate the recurrence of the upper interincisal diastemas, the factors associated to the relapse and stability, some treatment proposals, and considerations

At the beginning of the last century, Angle [1] described median diastema as a common form of malocclusion where there is a space between the upper central incisors and, very rarely, between the lower central incisors. According to the author, the width of this space usually varies from 1 to 4 mm and always presents an unpleasant appearance, and may interfere with speech, depending on the width. Later, according to Bishara [2], diastemas were described as

In publishing the Six Keys for normal occlusion, Andrews [3] stated in Key V that there must be fair points of contact throughout the dental arch, in the absence of dental size discrepancy. According to this information, diastemas are also considered a malocclusion

The prevalence of diastemas varies greatly according to age and ethnic group [4, 5]. In perma-

The literature demonstrates that the prevalence of diastemas decreases with age, mainly due to the development of occlusion. Richardson et al. [6] observed 5307 children between 6 and 14 years of age and, as a result, obtained a prevalence of 38% of children with median diaste-

In a longitudinal study, Bergström et al. [7] aimed to observe the behavior of median diastemas in relation to the presence of the labial frenulum, in children of age 9 years on average, followed up after 2, 5, and 10 years. In the first two follow-ups, the group submitted to the removal of the labial frenulum presented a larger number of cases with closed diastemas than the control group. However, 10 years after the first consultation, there was no difference between groups. The authors found that the number of children with diastema declined with age and that there were a considerable number of individuals where diastemas closed from

Steigman and Weissberg [8] found a prevalence of 50% in 1279 adolescents with spaced permanent dentures, ranging in age from 12 to 18 years. On the other hand, Steigman et al. [9]

for retention.

96 Current Approaches in Orthodontics

by Andrews.

14 to 19 years.

**2.1. General prevalence**

**2.2. Prevalence according to age**

**2. Definition and epidemiology of diastemas**

just clinically visible spaces between two or more adjacent teeth.

nent dentures, the prevalence of diastemas varies from 1.7 to 38% [4].

mas above 6 years of age, 56% at 8 years, and 18% at 14 years.

Richardson et al. [6] observed a higher percentage of 6-year-old girls with median diastemas; however, at age 14, the opposite occurred. The authors believe that this is due to an earlier maturation of the girls in relation to the boys.

The findings of Steigman and Weissberg [8] corroborate those of the other authors, since they found dimorphism only in the subgroup between 14 and 16 years. There was no difference between genders in the 12- to 14-year-old and 16- to 18-year-old groups. Another study published by Steigman et al. [9] supported this finding, demonstrating that there was no difference between genders regarding the number of spaces in the arches in a sample of patients aged 16–22 years. It was also found that the number of diastemas decreased with age in both genders, but this occurred earlier in females than in males.

#### **2.4. Prevalence according to race**

In an epidemiological study on the prevalence of diastemas in white and black ethnic groups, Richardson et al. [6] observed, in a sample of children between 6 and 14 years of age, a higher frequency of diastemas in blacks at almost all ages. A prevalence of 23% of blacks at 14 years of age with diastema was found, differing from 14% of whites of this age with central interincisive spaces.

Similarly, Lavelle [4] found a higher incidence of central interincisive diastemas in melanodermas (5.5%) than in leucodermas (3.4%) and a lower incidence in xanthomas (1.7%). Likewise, McVay and Latta [5] found a very significant difference between the prevalence of blacks (29%) compared to the percentage of 20% of adults presenting this space in both the white and yellow race.
