Diastema and trismus

The space that arises as a result of the spacing of teeth is called a diastema, if it is located between the central incisors, or an impaction, if it is found between any other teeth in the oral cavity.

With multiple aetiologias and varying sizes, diastema and tremens can interfere with the normal function of the arches or can be aesthetically disturbing.

In terms of incidence, diastema is more common than trismus and in terms of mode of occurrence both may be congenital or acquired.

It is important to know that diastema and trismus are physiological spaces in the temporary or mixed dentition, the latter of which contains both deciduous and permanent teeth.

Under normal conditions, the spaces may shrink or even close completely from the age of 12-13 years, when the eruption of the canines ends.

Before considering correction of diastemas and trismus, the causes that can cause them must be identified and the factors that could maintain them removed.

If the presence of these spaces does not interfere with the functioning of the dento-maxillary appliance, the option to close becomes a personal one and is based on aesthetic reasons.


  • Abnormal relationship of the tongue to the dental arches: too much or medium but constant pressure applied by the tongue on the oral dental surfaces leads to vestibularization of the teeth, with the appearance of spaces.

  • Low-insertion labial frenum: Frenulum are structures that connect, at the upper and lower midline, the inner surface of the lips to the gums. Too low an insertion leads to a thickened appearance of fixed gingiva, with diastema appearing in the central incisors.

  • Malocclusion: a malocclusion that is not uniform in the contact surfaces leads to overstraining of certain dental units with diastema and trismus.

  • Changes in the composition and structure of the bone component: teeth are supported in the oral cavity by bony structures called alveoli, which are held together by hard, resistant tissue. Any change at this level, such as bone loss due to infection or periodontitis, leads to changes in tooth alignment, manifested by rotations and spacing.

  • Anodontia: congenital absence of one or more teeth leads to diastemas and trismus if the other teeth cannot close the space during the natural process of growth and alignment.

Although there are patients who are not bothered by diastema and trismus when they do not hinder the normal functioning of the dento-maxillary apparatus, there are also those who feel that their aesthetics are affected and therefore turn to the dentist for correction.

The indication for treatment to close diastemas and trismus is orthodontics. The duration of treatment cannot be specified at the outset because there are a number of factors that can alter this parameter:


  • Space size: there is a direct proportional relationship between the size of the interdental space and the duration of orthodontic treatment.

  • Location of spaces: teeth located mandibular have a denser bone cortex and are more resistant to changes.

  • Teeth targeted: a tooth with a single root can be aligned more easily than one with 3 roots.

As this is a longer process of correction, the patient must be open and cooperative to ensure the desired results. However, diastema and trismus teeth can also be considered as features that add beauty to the patient.

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