**3. Diastemas and occlusion development**

It is a consensus in the literature that, during the development of occlusion, in the deciduous and mixed dentition stages, the presence of diastemas is a characteristic of normality [2, 10–14]. Nevertheless, Richardson et al. [6] suggested that median diastemas are more than a phase of development eliminated over time, due to the high prevalence found in 18% of adolescents with medium diastemas. Edwards [15] stated that if the median space is greater than 2 mm, it is unlikely to close spontaneously. It was observed in a longitudinal study in adolescents that there was stability in most of the existing diastema, although some were eliminated even after the eruption of permanent canines [9].

#### **3.1. Primary dentition**

Authors have suggested that these spaces in the primary dentition are normal and would have the function of assisting in the eruption of permanent teeth [10, 16]. In describing the biogenetic course of the deciduous dentition, Baume [11] classified the dental arches according to the spaces designated by him as type I, with anterior spaces, and type II, without such spaces. In this work, the author cites that one type cannot progress to the other.

eruption; genetic factors such as large jaws and small teeth; tooth size, interarch discrepancy, agenesis, and micro-diseases; characteristics relating to ethnic groups; low insertion of the upper labial frenulum, preventing the mesial migration of the maxillary central incisors during canine eruption; dental rotations; supernumerary teeth, among which a classic example is the mesiodens; pathological conditions, such as proximal caries, periodontitis, cysts, and tumors; and, finally, the deleterious habits, exemplified by the lingual interposition and sucking lip. In the second category, the author refers to dental extractions and occasional dental size discrepancies, caused by extractions as diastematic agents during orthodontic treatment. Steigman et al. [9] evaluated the stability of permanent denture spaces during adolescence in untreated patients, and also investigated the association of tooth spacing with tooth size and dental arch dimensions. They observed that women with spaced dentition had smaller dental widths and similar arch dimensions than those without dental spacing. In them, the spaces were equally distributed in both arches. On the other hand, in men, there was an equivalence of the dental dimensions, but the intercanine distances and superior interpremolars were greater in those with a spaced dentition. This is the reason why, in males, a greater number of

Stability of Diastemas Closure after Orthodontic Treatment

http://dx.doi.org/10.5772/intechopen.82480

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Oesterle and Shellhart [27] mentioned that the presence of generalized spaces in the dental arches may be the result of discrepancies between the size of the teeth and their respective apical bases, muscular imbalances, deleterious habits, and loss or absence of teeth. The large jaw and/or jaw combination with normal or slightly reduced teeth size is related to inherited characteristics, but may also be a sign of endocrine imbalances, which result in excess growth

Gass et al. [18], when evaluating the correlation between the heredity and the presence of the medium diastemas in leucodermas and melanodermas, found that the genetic expression was more significant for the whites than for the black ones, where the existence of an interincisive diastema is more related to environmental factors, such as excessive protrusion of the incisors, a predisposing periodontal tissue, habits, and absence of teeth. However, in relation to the stability of the treatment, an association between heredity and median diastema recur-

In the same year, Mondelli et al. [24], in a comprehensive review work describing the etiology and the various diastema treatments, add that there are diastemas of iatrogenic etiology. As examples, the authors cited the rapid expansion of the maxilla and a type of mechanics inadequate for diastema closure, where an elastic band is positioned on the central incisors, but slides in the cervical direction, causing periodontal damage and root approximation, with

In the deciduous and mixed dentition phases, interincisive diastemas are considered normal [11–13, 16]. However, in the permanent dentures, diastema is frequently associated with several occlusal problems, which include missing teeth, dental anomalies, abnormal bone

consequent divergence of the crowns, making the diastema even wider.

**4. Treatment of anterosuperior diastemas**

spaces were found in the maxilla than in the mandible.

hormone, such as acromegaly.

rence has been reported [28].

Moyers [14] reported that there is a generalized spacing in the anterior region of the upper and lower arches in the deciduous dentition, which increases significantly after this dentition has been completed.
