3.3. Subgroup Study
Cohen’s Kappa index was calculated to determine the index of agreement between the two examiners on the analysis of the somatic development level and the salivary aspects for a sample of 30 children.
Regarding the level of somatic development, the two examiners agreed on 19 children with normal development, 6 children with a lower level of somatic development and 2 children with a higher level of somatic development. However, examiner 1 rated 2 children as having a normal level, while examiner 2 rated them as having a lower level, respectively a higher level of somatic development. Also, examiner 1 rated 1 child as having a lower level, while examiner 2 rated the child as having a normal level of development. Overall, there was a good level of agreement between the analysis of the two medical examiners, κ = 0.788, p < 0.0005.
Regarding the salivary aspects, the two examiners agreed on 19 children with a normal level of secretion, 7 children with hyposecretion and 2 children with hypersecretion of saliva. Thus, examiner 1 rated 1 child as having a normal level of saliva secretion, while examiner 2 rated the child as having a hyposecretion. Also, examiner 1 rated 1 child as having a hypersecretion, while examiner 2 rated the child as having a normal level. Overall, there was a very good level of agreement between the two examiners’ analysis, κ = 0.863, p < 0.0005.
The study lot comprised 68 girls (representing 48.57% of the entire lot) and 72 boys (51.43%), divided by age as follows: 81 children (57.86%) with ages between 6 and 10 years old, and 59 children (42.14%) with ages between 11 and 14 years old. More than half of the children had urban residence, 40 girls (58.8% of all girls) and 47 boys (65.3% of all boys), while 28 girls 41.2%) and 25 boys (34.7%) had rural residence.
Figure 9 emphasizes the distribution of the study group according to gender, age group and place of origin.
A chi-square test for association was conducted between the presence of malocclusions and demographic data (gender, age group, and place of origin). All expected cell frequencies were greater than five. There were no statistically significant associations between the presence of malocclusions and the demographic data, χ2(1) = 1.029, p = 0.310 (for gender), χ2(1) = 1.435, p = 0.231 (for age groups) and χ2(1) = 0.759, p = 0.384 (for the place of origin).
Approximately half of the children included in the study lot brushed their teeth once a day, divided as follow: 55.6% of children from the age group 6-10 years old, and 47.5% of children with ages above 11 years old. Almost a third of smaller children never brush their teeth, compared to only 13.6% older ones. Children above 11 years old are more aware of the need to brush several times a day, as 28.8% brush their teeth twice a day, and 10.2% even three times a day. Thus, the differences between the age groups relative to the frequency of brushing teeth are statistically significant, χ2(3) = 14.655, p = 0.002.
Oral Parameters’ Analysis
Oral respiration has been identified in 10 children with rural residence (representing 18.9% from all children from the countryside), compared to only 6 children with urban residence (representing 6.9% from all children from urban areas), and these differences are statistically significant (χ2(1) = 4.663, p = 0.031). Also, this type of respiration is associated with a low level of somatic development (χ2(2) = 59.756, p < 0.0005), with 87.5% of children within this level being characterized by oral respiration, compared to 8.9 children with normal respiration. The rest of the 12.5% children have a normal level of development, and no child has a high level of development. Similar results have been identified for salivary aspect, as 81.3% of children with oral respiration have a low level of saliva secretion (χ2(2) = 62.246, p < 0.0005). More than half of all children with oral respiration have a defective phonation (62.5%), thus there is a positive association which is statistically significant between these parameters (χ2(1) = 27.928, p < 0.0005). Other two parameters are associated with the oral respiration: thumb sucking (specific for 68.8% children with oral respiration) and placing objects between maxillaries (specific for 62.5% children with oral respiration), with χ2(1) = 58.637, p < 0.0005, respectively χ2(2) = 19.205, p < 0.0005.
All children with infantile deglutition have a defective phonation, therefore there is a significant association between these variables, χ2(1) = 31.888, p < 0.0005. Half of these children have a low level of secretion, while the other half is characterized by a normal level, and none with hyper-secretion, the differences being statistically significant, χ2(2) = 6.174, p = 0.046. Infantile deglutition is also associated with placing objects between maxillaries (specific for 83.3% children with infantile deglutition), with χ2(1) = 14.967, p < 0.0005.
More than half of all children identified with thumb sucking (62.5%) have a low level of somatic development and a low level of saliva secretion, thus leading to a significant association between these variables, χ2(2) = 24.775, p < 0.0005, respectively χ2(2) = 32.212, p < 0.0005. Defective phonation is also associated with thumb sucking, with 56.3% of children with thumb sucking having phonation issues, χ2(1) = 20.864, p < 0.0005, and with placing objects between the maxillaries, with 81.3% children with thumb sucking having this behavior, χ2(1) = 40.307, p < 0.0005.
He majority of children identified with slow mastication (69.2%) have a low level of somatic development and a normal level of saliva (61.5%), and no high levels for any of these two parameters, thus there are statistically significant differences between these varia bles, χ2(2) = 25.908, p < 0.0005, respectively χ2(2) = 6.709, p = 0.035.
Children with bruxism have mostly a normal level of saliva secretion (82.4%), but 17.6% have a hyper-secretion, thus the differences between these parameters are statistically significant, χ2(1) = 6.726, p = 0.035.
Two thirds of children (66.7%) with a hypo-secretion of saliva are also characterized by a low level of somatic development, and 33.3% of children with saliva hyper-secretion have a high level of somatic development, thus there are statistically significant differences between salivary aspects and somatic development, χ2(4) = 53.292, p < 0.0005. Also, a quarter of children with saliva hypo-secretion have ages between 11 and 14 years old, compared with only 7.4% children aged between 6 and 10 years old. Normal secretion was identified for 85.2% of children aged below 10, and only 69.5% children with ages above 10. The differences between age groups regarding the salivary aspects are statistically significant, χ2(2) = 8.743, p = 0.013.
Onychophagia was identified in 20.7% of all children, 34.5% of them had saliva hypo-secretion, 6.9% had hyper-secretion, and the rest had normal levels. Most children without onychophagia had normal levels of saliva, therefore the differences between these variables are statistically significant, χ2(2) = 11.121, p = 0.004.
The habit of placing objects between the maxillaries was encountered in 29 children (representing 20.7% of the entire study lot). Around half of them (55.2%) had a normal level of saliva secretion, compared to 84.7% children without this habit, and 41.4% had hypo-secretion, compared to 8.1% from the opposite group, thus statistically significant differences were identified between these groups, χ2(2) = 20.022, p < 0.0005. Similar percentages were identified regarding the level of somatic development, χ2(2) = 10.100, p = 0.006.
M and control groups comparison
Oral respiration (observed in 16 children, 11.43% of the entire study lot), infantile deglutition (6 children, 4.3%), thumb sucking (16 children, 11.43%) and placing objects between the maxillaries (29 children, 20.7%) were diagnosed only in children from the M group. For all these parameters, the differences between the two study groups are statistically significant (p < 0.0005) (
Table 4).
The analysis of children’s somatic development identified a low level for almost 18% of the study lot (25 children), with two thirds of them being included in the M group and one third in the control group. A normal level was identified for 107 children, with a similar distribution between the two study groups, while a high level was identified for 8 children, equally distributed between the M and control group. The differences between the two groups were not statistically significant, p = 0.136 (
Table 4). Similar results were also obtained for slow mastication, as only 13 children presented this sign, with 61.5% of them in the M group and 38.5% in control group, p = 0.382 (
Table 4).
The presence of bruxism is another sign that is not directly related with the presence of malocclusions; 17 children have this disease, almost two thirds being included in the M group and the rest in the control group, but no statistically significant differences were identified between the two groups (
Table 4).
Smoking status and dietary factors (consumption of acid drinks and consumption of seeds) are habits that have been identified in both groups, in rather small percentages, with similar distributions and no statistically significant differences between groups (
Table 4).
For the 70 children within the M group, the distribution by class was the following: 34 children (48.6%) had class I, 30 children (42.9%) and only 6 children (8.6%) had an Angle class III malocclusion. There were no statistically significant differences between these three classes relative to the demographic data (gender, age groups and place of origin), p > 0.05. The distribution of oral parameters by the malocclusion class is presented in
Table 5.
All children with oral respiration had Angle class II malocclusions, as well as all children with thumb sucking habit, while all children with infantile deglutition had only Angle class I malocclusions, therefore the differences between classes regarding these variables were statistically significant, p < 0.05 (
Table 5). The majority of children with a low level of somatic development have Angle class II malocclusions, while those with a high level have Angle class III malocclusions; the normal level is mostly defined by Angle class I malocclusions, therefore the differences between classes are statistically significant, p < 0.0005 (
Table 5). Similar associations were identified for the level of saliva secretion, p = 0.006 (
Table 5).
Almost all children with bruxism have Angle class I malocclusions, while those without bruxism have Angle class II malocclusions, differences being statistically significant, p = 0.009. A similar distribution was identified for the consumption of acid drinks, as children who consume this kind of drinks mostly have Angle class I malocclusions, while those who don’t have Angle class II malocclusions, p < 0.0005 (
Table 5).
For the following parameters: defective phonation, slow mastication, smoking status, onychophagia, the habit of placing objects between the maxillaries, consumption of seeds, frequency of teeth brushing, there were no significant differences between classes, p > 0.05 (
Table 5).
Logistic regression
A binomial logistic regression was performed to ascertain the effects of gender, place of origin, defective phonation, bruxism, frequency of teeth brushing, onychophagia, oral respiration, infantile deglutition, placing objects between the maxillaries, thumb sucking and salivary aspects on the likelihood that children present malocclusions. These parameters were chosen based on their statistical significance associated with the presence of malocclusions. There was one standardized residual with a value of 3.194 standard deviations, which was kept in the analysis. The logistic regression model was statistically significant, χ2(14) = 91.584, p < .0005. The model explained 64.0% (Nagelkerke R2) of the variance in heart disease and correctly classified 84.3% of cases. Sensitivity was 77.1%, specificity was 91.4%, positive predictive value was 90.0% and negative predictive value was 80.0%. Only gender, place of origin and no teeth brushing were statistically significant. Thus, girls have higher odds of developing malocclusions compared to boys, and children living in urban areas compared to rural areas, as well as children who never brush their teeth.