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The establishment and subsequent worsening of a malocclusion is the result of a combination of factors dominated by the interaction between inheritance and environment and follows a dynamic process of temporal evolution. This transversal study, based on a sample of 579 children from the Caserta area in Southern Italy, investigates the potential worsening of malocclusions with age by measuring the relationship between the severity level of orthodontic abnormalities, evaluated through the IONT-DHC classification, and the age of the subjects. Our results show that a statistically significant association exists (p &lt; 0.0001) between the overall severity of the malocclusion and the age of the subjects, underlining the importance of an early orthodontic prevention and highlighting that large sections of the population still need to be sensitized to orthodontic problems.
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Annali di stomatologia
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Association between age and severity of malocclusion in the pediatric age: a cross-sectional study
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Association between age and severity of malocclusion in the pediatric age: a cross-sectional study
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                                                                                                   Original article



    Association between age and severity of
    malocclusion in the pediatric age:
    a cross-sectional study




                                                                                                        li
                                                                                                     na
    Valeria Luzzi1 DDS, PhD                                  combination of factors dominated by the interaction
    Mario Di Traglia2 MD                                     between inheritance and environment, when favor-
    Annarita Vestri2 MD                                      able or unfavorable growth vectors are conditioned by




                                                                                            io
    Gaetano Ierardo1 DDS, PhD                                postnatal risk factors, represented by spoiled habits
    Francesco Covello1 DDS                                   (1-10). Primary and secondary orthodontic prevention
    Denise Corridore1 DDS                                    works by guiding the growth vectors, thus preventing




                                                                       az
    Maurizio Bossù1 DDS, PhD                                 the establishment or aggravation of a malocclusion
    Antonella Polimeni1 MD, DDS                              during the growth stages. Consequently the early tim-
                                                             ing of orthodontic intervention aims to restore the nor-
                                                             malization of craniofacial growth vectors (11-13).




                                                                     rn
    1 Department of Oral and Maxillofacial Sciences,         In a previous study (14) carried out on a sample of
    “Sapienza” University of Rome, Rome, Italy               579 children from the Caserta area in Southern
    2 Department of Public Health and Infectious Diseases,
                                                             Italy, we observed an overall prevalence of maloc-
    “Sapienza” University of Rome, Rome, Italy               clusions of 49% with a need for orthodontic treat-




                                                          e
                                                             ment equal to 19%. These values were significantly
                                                             lower than those of similar studies in the literature
    Corresponding author:
    Valeria Luzzi
    Department of Oral and Maxillofacial Sciences
                                                 I     nt    (15,16) where, however, the average age of the
                                                             samples was sensibly higher than ours, reaching the
                                                             age of adolescence and pre-adolescence.
    “Sapienza” University of Rome                            From this comparison it was clear that the establish-
    Via Caserta 6                                            ment and subsequent worsening of a malocclusion,
    00161 Rome, Italy                                        starting from the completion phase of the deciduous
                                              ni
    E-mail: valeria.luzzi@uniroma1.it                        dentition, follows a dynamic process of temporal
                                                             evolution. The aim of this transversal study, based
                                                             on the same previously described sample, was to in-
                                    io


    Summary                                                  vestigate the potential worsening of malocclusions
                                                             with age, independently of early orthodontic inter-
    The establishment and subsequent worsening of a          ventions, by measuring the relationship between the
             iz



    malocclusion is the result of a combination of fac-      severity level of orthodontic abnormalities and the
    tors dominated by the interaction between inheri-        age of the subjects.
    tance and environment and follows a dynamic
           Ed




    process of temporal evolution. This transversal
    study, based on a sample of 579 children from the        Materials and methods
    Caserta area in Southern Italy, investigates the po-
    tential worsening of malocclusions with age by           Our sample included 579 children aged between 2
    measuring the relationship between the severity          and 9 years. The selection of the sample, which
    level of orthodontic abnormalities, evaluated            availed itself of the collaboration of 45 pediatricians
IC




    through the IONT-DHC classification, and the age         from the province of Caserta, and the procedures
    of the subjects. Our results show that a statistical-    used in collecting the data are described in full details
    ly significant association exists (p < 0.0001) be-       in our previous article (14). The research was con-
    tween the overall severity of the malocclusion and       ducted in full accordance with the World Medical As-
C




    the age of the subjects, underlining the impor-          sociation Declaration of Helsinki and approved by the
    tance of an early orthodontic prevention and high-       Medical Ethical Committee of Sapienza University of
    lighting that large sections of the population still     Rome. The parents signed an informed consent be-
    need to be sensitized to orthodontic problems.           fore the dental visit.
©




                                                             For each child we measured orthodontic parameters
    Key words: malocclusion, pediatric age, prevention.      related to the malocclusions of overjet, reverse over-
                                                             jet, overbite, anterior openbite, and crossbite. The
                                                             need for treatment was then evaluated using the
    Introduction                                             IONT-DHC (Index of Orthodontic Treatment Need -
                                                             Dental Health Component) classification (17-19) to
    The occurrence of a malocclusion is the result of a      which we applied some minor modifications to take

    Annali di Stomatologia 2018;IX(1):35-42                                                                        35
    V. Luzzi et al.


    into account our operating methods. Each child was                   Results
    then assigned an overall IONT-DHC index, defined
    as that corresponding to the most severe occlusal                    The sample consisted of 579 children, 306 males
    anomaly. The only criterion for exclusion from the                   (52.8%) and 273 females (47.2%), aged between 2
    study was the presence of orthodontic treatments,                    and 9 years (mean=5.73, SD=1.65, median=6), of




                                                                                                                         li
    completed or in progress ones.                                       predominantly Italian nationality (99.3%), and in early
                                                                         deciduous and mixed dentition.




                                                                                                                      na
    Statistical analysis                                                 As reported in our previous study (14), the sample
    To evaluate the association between age and aggra-                   presented an overall prevalence of malocclusions of
    vation of the malocclusions, a transversal approach                  49.0%, with 95% CI=(44.9-53.1%), and a need for or-
    was used, thus assuming the ergodicity of the sam-                   thodontic treatment of 19.3%, with 95% CI=(16.2-
    ple.




                                                                                                          io
                                                                         22.8%), with no statistically significant differences be-
    The age of the children was discretized into 8 age                   tween males and females.
    groups ranging from 2 to 9 years.                                    Table 2 summarizes the result of multinomial logistic
    Starting from the IONT-DHC index, the severity of the                regression analysis for the association between age




                                                                                   az
    malocclusion was divided into 3 classes (Tab. 1) cor-                and overall severity of the malocclusion. This model
    responding to absence of pathology (class 0), pres-                  shows statistically significant changes with age
    ence of a mild pathology with no need for treatment                  (p < 0.0001) with a negative trend for class 0 and with
    (class 1) and presence of a pathology with need for                  a positive trend for class 1, while the trend with age




                                                                                 rn
    treatment (class 2).
                                                                         for class 2 is substantially constant (Fig. 1). This re-
    The association of age with the severity of the exam-
                                                                         sult indicates that as the age increases the number of
    ined malocclusions (overjet, inverse overjet, overbite,
                                                                         subjects with all occlusal parameters in the norm
    anterior openbite, and crossbite), taken both individu-




                                                                  e
                                                                         (class 0) decreases from 62% to 41% while that of
    ally and in combination through the overall IONT-
                                                                         subjects with at least one slightly altered occlusal pa-
    DHC index, was evaluated using the multinomial lo-
    gistic regression model.
    For regression analysis, the Statistica software pack-
    age from TIBCO Software Inc. (formerly from StatSoft
                                                  I            nt        rameter (class 1) increases from 19% to 40%. The
                                                                         exclusion from the study of children with an orthodon-
                                                                         tic treatment in progress or concluded explains the
                                                                         trend with age approximately constant and equal to
    Inc.) was used.
                                                                         19% of the percentage of subjects with at least one
                                               ni

    Table 1. Correspondence between value of the IONT-DHC index, status of the occlusal parameters, need for treatment,
    pathology level, and statistical class.
                                      io


    IONT-DHC index          Occlusal parameters               Need for treatment                     Class                  Pathology
    1                       Normal                            Absent                                 0                      Absent
               iz



    2                       Mildly altered                    Absent or not recommended              1                      Mild
    3,4,5                   Altered                           Present                                2                      Severe
             Ed




    Table 2. Results of regression analysis for the overall malocclusion gravity.

    Total IONT         Classification of cases - Odds ratio: 16.381                         Log odds ratio: 2.796
    Observed               Predicted 0                 Predicted 1              Predicted 2                         Correct (%)
IC




    0                      285                         0                        0                                   100.0
    1                      10                          114                      42                                  68.7
    2                      0                           21                       87                                  80.6
C




                                Parameter estimates distribution: ORDINAL MULTINOMIAL Link function: LOGIT
    Effect             Level of       Column       Estimate          Standard    Wald Stat.      Lower        Upper           p
                       effect                                                                    CL 95%       CL 95%
©




    Intercept 1                       1            -4.232            0.726          34.01        -5.655       -2.810          <0.0001
    Intercept 2                       2            2.663             0.601          19.66        1.486        3.841           <0.0001
    Age                0              3            -0.911            0.279       197.13          3.365        4.457           <0.0001
    Age                1              4            0.478             0.102       22.00           0.278        0.678           <0.0001
    Scale                                          1                 0                           1            1


    36                                                                                          Annali di Stomatologia 2018;IX(1):35-42
    Association between age and severity of malocclusion in the pediatric age: a transversal study




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    Figure 1. Association between age and total IONT-DHC index. (a) level 0: no malocclusion; (b) level 1: mild malocclusion;
    (c) level 2: malocclusion with treatment need.
©




    severely impaired occlusal parameter (class 2), as              For inverse overjet and anterior openbite, the number
    this group only includes children whose malocclusion            of cases present in the sample was not sufficient to
    had not yet been treated.                                       complete the analysis. In the case of overbite (Fig. 2)
    Turning now to individual malocclusions, Tables 3, 4,           and overjet (Fig. 3), the association of the severity of
    and 5 report the results of the analysis for overjet,           malocclusion with age, despite following trends simi-
    overbite, and crossbite malocclusions, respectively.            lar to those seen for the severity of the overall maloc-

    Annali di Stomatologia 2018;IX(1):35-42                                                                               37
    V. Luzzi et al.


     Table 3. Results of regression analysis for overbite.
     OVERBITE                                      Classification of cases - Odds ratio: 0.992                 Log odds ratio: -0.008
     Observed                    Predicted 0                        Predicted 1                 Predicted 2                    Correct (%)
     0                           369                                51                          2                              87.4




                                                                                                                                         li
     1                           61                                 47                          5                              41.6




                                                                                                                                      na
     2                           0                                  20                          4                              16.7


                      Parameter estimates distribution: ORDINAL MULTINOMIAL Link function: LOGIT
    Effect            Level of            Column        Estimate              Standard       Wald Stat.       Lower CL     Upper CL      p




                                                                                                                          io
                      effect                                                  Error                           95%          95%
    Intercept 1                                1             0.93                 0.45           4.32            0.05         1.81            0.04
    Intercept 2                                2             3.79                 0.50           56.47            2.80           4.78        <0.0001




                                                                                                az
    Age                                        4             0.13                 0.07           2.94             -0.02          0.28         0.09
    Scale                                                       1                     0                            1              1




                                                                                              rn
    Table 4. Results of regression analysis for overjet.
    OVERJET                   Classification of cases - Odds ratio: 2,821                                Log odds ratio: 1,037




                                                                                 e
    Observed                             Predicted 0                     Predicted 1            Predicted 2                    Correct (%)
    0                                    392                             52                     0                              88.3
    1
    2
                                         71
                                         0
                                                         I               31
                                                                         7
                                                                              nt                0
                                                                                                6
                                                                                                                               30.4
                                                                                                                               46.2


                      Parameter estimates distribution: ORDINAL MULTINOMIAL Link function: LOGIT
                                                      ni
     Effect           Level of            Column        Estimate              Standard      Wald Stat.        Lower CL     Upper CL     p
                      effect                                                  Error                           95%          95%
     Intercept 1                          1             2.320                 0.519          20.023           1.304        3.337         <0.0001
                                             io


     Intercept 2                          2             5.846                 0.645          82.255           4.583        7.110         <0.0001
     Age                                  4             -0.024                0.083          0.085            -0.187       0.138         0.770
                iz



     Scale                                              1                     0                               1            1
              Ed




     Table 5. Results of regression analysis for crossbite.
     CROSSBITE            Classification of cases - Odds ratio: 2,821                                   Log odds ratio: 1,037
     Observed                        Predicted 0                     Predicted 1                    Predicted 2                Correct (%)
     0                               392                             52                             0                          88.3
IC




     1                               71                              31                             0                          30.4
     2                               0                               7                              6                          46.2


                      Parameter estimates distribution: ORDINAL MULTINOMIAL Link function: LOGIT
C




     Effect           Level of            Column        Estimate              Standard      Wald Stat.        Lower CL     Upper CL      p
                      effect                                                  Error                           95%          95%
     Intercept                            1             2.619                 0.722          13.144           1.203        4.034         0.0003
©




     Age                                  2             0.209                 0.121          2.986            -0.028       0.447         0.084



    clusion, does not show statistically significant varia-                           empty. For class 2 there is an increasing trend with
    tions. As for crossbite (Fig. 4), the presence of an al-                          age, but even in this case it does not reach statistical
    teration of any entity automatically induces a need for                           significance (p=0.08).
    orthodontic treatment and consequently class 1 is

    38                                                                                                        Annali di Stomatologia 2018;IX(1):35-42
    Association between age and severity of malocclusion in the pediatric age: a transversal study




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    Figure 2. Association between age and overbite. (a) level 0: absent; (b) level 1: mild; (c) level 2: severe.




    Annali di Stomatologia 2018;IX(1):35-42                                                                         39
    V. Luzzi et al.




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    Figure 3. Association between age and overjet. (a) level 0: absent; (b) level 1: mild; (c) level 2: severe.




    40                                                                                         Annali di Stomatologia 2018;IX(1):35-42
    Association between age and severity of malocclusion in the pediatric age: a transversal study




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    Figure 4. Association between age and crossbite. (a) level 0: absent; (b) level 2: present.
           Ed




                                                                      years a statistically significant association exists be-
    Discussion                                                        tween the severity of the overall malocclusion, de-
                                                                      fined as the combination of all considered malocclu-
    Several Authors (20-21) agree with the implementa-                sions, and the age of the subject. The percentage of
    tion of preventive programs for children, as they state           children with class 0 (normal orthodontic parameters)
    that oral health education to caregivers have led to              range from 62% at 2 years of age to 41% at 9 years
IC




    great benefits. Information on oral health care should            of age while those with at least one slightly impaired
    be provided to mothers during pregnancy, to increase              parameter (class 1) increase from 19% at 2 years of
    their knowledge about gestational care of oral health,            age to 40% at 9 years, indicating a clear trend of
    and to prevent problems that may occur both in the                worsening of the occlusal state with the increasing
C




    mothers themselves and in their children such as pre-             age.
    term low birth weight (22). Pregnant women who re-                The percentage of children with at least one occlusal
    ceive this information become health promoters in the             parameter altered in such a way as to require treat-
    family, as well as multiplying agents of oral health ed-          ment (class 2) is equal to 19% and this is explained
©




    ucation. Alves et al. (23) in their study found that chil-        by the study criteria exclusion. In fact the study ex-
    dren who started participating in the program, and                cluded all the children who were undergoing or had
    women who have received pertinent information                     completed an orthodontic treatment; that 19% there-
    since pregnancy, presented fewer oral diseases than               fore indicates only the percentage of children who
    those who never participated in the oral health pro-              had not yet started orthodontic treatment despite this
    gram.                                                             being necessary. Such a large number of untreated
    Our study shows that in the age ranged from 2 to 9                orthodontic cases indicate that in some sections of


    Annali di Stomatologia 2018;IX(1):35-42                                                                                41
    V. Luzzi et al.


    the population there is still a lack of sensitivity to or-                    Stomatol (Roma). 2011;2(1-2):13-18.
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                                                                                  factor for malocclusion: a case-control study in children. Int
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                                                                                  J Paediatr Dent. 2013;23(4):274-278.
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                                                                                                                                 li
    the numerical entity of the sample was not sufficient                         ti in tema di carie della prima infanzia. Dental Cadmos.
    to highlight in a statistically significant way an associ-                    2009;4:61-79.




                                                                                                                              na
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                                                                                  in dentatura decidua mediante l'utilizzo del dispositivo Nite
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    The present study identified a statistically significant




                                                                                        az
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                                                                                      rn
                                                                                  with primary snoring. Eur Rev Med Pharmacol Sci. 2016
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                                                                         e
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    42                                                                                                Annali di Stomatologia 2018;IX(1):35-42
