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26 Orthodontics KCE Reports 77
PERIODONTAL PROBLEMS
Some malocclusion features such as crowding with displacement of the contact-points
of the teeth and large overjet and some habits such as mouth breathing have been
related to gingivitis. However the strength of these associations is only weak to
moderate 4 . It should be noted that search description nor appraisal criteria of this
review were given. Probably there is a significant association between these features and
gingivitis, when the oral hygiene is fairly average to poor, as was revealed in a study of
Ainamo (1972) 4 , n
The systematic review of the Swedish Council on Technology Assessment in Health
Care 2 found insufficient evidence to conclude on the relationship of untreated
malocclusions and periodontal problems.
Because the lack of good evidence, the need for further randomized controlled trials is
urgent in this field.
MALOCCLUSION AND CARIES
Sometimes it is claimed that persons with certain types of malocclusion, e.g. crowding,
are more prone to caries because of more difficulties with brushing and oral hygiene as
a whole. In these cases, it is assumed that orthodontics can help to prevent caries.
However, the systematic review of the Swedish Council on Technology Assessment in
Health Care 2 found evidence, but only of low quality, for the statement that
malocclusion is not associated with a higher frequency of caries.
MALOCCLUSION AND SPEECH PROBLEMS
The relation between major speech disturbances and malocclusion can rarely be
observed. Consequently a speech disturbance is seldom an indication for the onset of
an orthodontic treatment. Children with a speech deviation should preferably be
referred to a phonetician or speech therapist 4
In a review Johnson et al (1999) stated that although it is accepted that teeth play an
important role in speech production, the relationship between tooth position and
speech remains controversial. There was found no definitive proof that alteration of
tooth position can improve articulation disorders and this while certain dental
irregularities show a relationship with speech disorders, this does not appear to
correlate with the severity of the malocclusion. The most consistently reported traits
are Class III arch relationship, anterior open bite, increased overjet, and spacing.
However, there is no clear evidence of a direct relationship between severity of
malocclusion and severity of misarticulation (Johnson et al, 1999).
The systematic review of the Swedish Council on Technology Assessment in Health
Care 2 found insufficient evidence to conclude on the relationship of untreated
malocclusions and speech problems (only one good quality study).
MALOCCLUSION AND RISK ON TRAUMA OF THE FRONT TEETH
Some limited scientific evidence was found that in patients with a large overjet and an
upper lip that does not protect the front teeth, the incidence of trauma to the anterior
teeth of the maxilla is higher 2 , 9 .
More specifically Nguyen et al (1999) 10 found that children with an overjet larger than 3
mm were approximately twice as much at risk of injury to their anterior teeth as were
children who had an overjet of less than 3 mm. Furthermore with increasing overjet the
risk of injury increased. There was also a difference between girls and boys, namely that
the effect of injury to anterior teeth is less for boys than for girls in the same overjet
group. This meta-analysis is of good quality. However the conclusions should be
considered with some caution because of the heterogenity in outcome of some of the
selected studies, the sizes of the control groups which were even lacking in some of the
n This is confirmed in the review of van Gastel J et al. (2007), which was published in 2007, Nov., after the
database search of this report had been closed.