health, prevalence of malocclusions and orofacial
dysfunctions in a sample of 4-5-year-old Bulgarian
kindergarden children.
2. Methodology
The subjects were randomly selected from
different kindergardens in the city of Plovdiv.
Inclusion criteria were the existence of fully
developed primary dentition, no orthodontic
treatment, Caucasian origin and a parental
consent for participation in the study. A total of 471
boys and girls participated in this cross-sectional
epidemiological study. The study was approved by
the Ethics Committee of the Medical University –
Plovdiv (Р-7781).
A postgraduate student in Orthodontics carried out
the entire diagnos tic assessment of all the children.
A specific form was designed for the purpose of
this study which contains information about dental
health, individual occlusion findings and functional
status. All the findings were made under good
lighting conditions. The metric parameters were
recorded by using a metal ruler marked in 0.5
mm. In this paper, all the orthodontic findings will
be described and the following parameters have
been selected and analyzed:
The type of primary dentition was assessed as
follows: with generalized spaces between the
teeth and localized spaces (Type 1), no spaces
(Type 2) or a crowded dentition (Type 3).
The overjet was measured in mm as a distance
between the labial surface of the lower and upper
incisors. A distance of (0-3 mm) was defined as a
normal distance. An increased overjet was divided
into two groups (3-6mm) and (>6mm), and a
negative overjet (<0mm), all measured in mm.
An anterior cross-bite was registered when one
or more maxillary incisors or canines occluded
lingually to the mandibular incisors or canines.
The criteria described by Foster & Hamilton 8 were
used for the primary canine and molar relationship
assessment.
• Class I - the tip of the maxillary primary canine
tooth is in the same vertical plane as the distal of
the mandibular primary canine
• Class II - the tip of the maxillary primary canine
tooth is anterior to the distal surface of the
mandibular primary canine.
• Class III - the tip of the maxillary canine is
posterior to the distal surface of the mandibular
primary canine.
Terminal plane relationships of the second primary
molar:
• Flush terminal - The distal surfaces of the upper
and lower second primary molars are in the same
anteroposterior level.
• Mesial step - the maxillary terminal plane is
posterior to the mandibular terminal plane
• Distal step - the maxillary terminal plane is
anterior to the mandibular terminal plane.
Molar and canine occlusions for each child were
recorded separately for the left and the right sides
of the dentition.
Stomatology Edu Journal
We have distinguished correct lateral occlusal
relationships, a unilateral and a bilateral cross bite,
a posterior edge-to-edge bite and a scissor bite.
An occlusion of the incisal edges was assessed
as an anterior edge-to-edge bite. An overbite
was graded according to the coverage of the
mandibular incisor by the most protruded
maxillary incisor. A normal one, when up to half of
the mandibular incisor is covered by the maxillary
incisor. An increased overbite, when more than
half of the mandibular incisor is covered by the
maxillary incisor. An overbite with gingival contact
was recorded when the mandibular incisor was
fully covered by the maxillary incisor and there was
a contact of the incisal edge with the gingiva. An
absence of a vertical overlap of the lower incisors
was described as an anterior open bite and
divided into two groups: moderate (<3mm) and
severe (>3mm).
Collection, evaluation and a statistical analysis of
the data were conducted using Microsoft® Excel
and SPSS Version 17.0 for Windows® (SPSS Inc.,
Chicago, IL., USA). Means and standard deviations
were determined as descriptive statistical values
in order to characterize univariate frequency
distributions of various variables. A comparison of
absolute frequencies of specific characteristics was
tested with Pearson’s chi-square test. The statistical
significance was assessed at the 5% level.
Prevalence of malocclusions in a sample of 4-5-year-old Bulgarian children
3. Results
A total of 241 males and 230 females were
examined. Normal occlusion relationships were
found in 35.6% of the sample. 126 or 26.8% of the
children have one malocclusion, followed by 129
children or 27.4% with two malocclusions, 27 or
5.7% with three malocclusions and then 21 or 4.5%
with four malocclusions. The total distribution of
malocclusions is 64.4%.
The most prevalent type of primary dentition is Type
1 with 78.2 % (with spacing), followed by 16.1%
Type 2 (no spacing) and 5.7% Type 3 (crowding).
The gender comparison is shown in Table 1. There
is a statistically significant difference between girls
and boys in the distribution of spacing, no spacing
and crowding which is more prevalent in girls
(with spacing χ 2=13,308, no spacing χ 2= 10,429,
crowding χ 2= 5,318).
The prevalence of overjet is shown in Table 2. A
total of 85.6% of all the children have a normal
overjet, 8.7% an increased overjet, 0.8% an
excessive overjet and 4.9% a decreased overjet.
Gender and age comparison of the normal,
increased and decreased overjet among 4 and
5-year-old boys and girls revealed no statistically
significant differences. An anterior cross-bite
was registered in 6.4% of all the children without
significant differences in age and sex.
The distribution of different sagittal relationships
of primary canine and second primary molars is
shown in Table 3 and respectively in Table 4. A
neutral occlusion of the primary canines was found
in 60 % of all children, a distal occlusion in 30%
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