Assessment of the relationship between body mass index (BMI) and dental age

doi:10.4236/health.2011.35045

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Vol.3, No.5, 253-257 (2011)

doi:10.4236/health.2011.35045

Health

Assessment of the relationship between body mass

index (BMI) and dental age

Maryam Zangouei-Booshehri1, Fatemeh Ezoddini-Ardakani1*, Hosein Agha Aghili2,

Akbar Sharifi3

1Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran;

*Corresponding Aut hor: ezoddini@gmail.com

2Department of Ort h o d o ntics, Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran;

3Faculty of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.

Received 29 March 2011; revised 21 April 2011; accepted 27 April 2011.

ABSTRACT

The aim of the study was to determine the rela-

tionship between Body Mass Index (BMI) and

accelerated dental development. The dental

developmental ages of 100 children aged be-

tween 8 and 12 years were determin e d us ing th e

Demirjian method and panoramic radiographs.

BMI status was determined for each subject on

the basis of the system developed by the Inter-

national Obesity Task Force. There was a sig-

nificant direct relationship between dental de-

velopment and BMI (P < 0.01). Obese children

have a higher rate of dental development com-

pared to normal children. CLINICAL RELE-

VANCE: This is an important variable to be con-

sidered when planning for dental and orthodon-

tic treatment s in obese children. Brief objectiv es

st atement: Over weight or obesity can accelerate

dental development. Accelerated dental devel-

opment in overweight children is important to

be considered in pediatric dentistry and ortho-

dontics.

Keywords: Dental Age; Body Mass Index (BMI);

Bone Age; Overweight

1. INTRODUCTION

Knowledge of the potential growth of a patient is one

of the important tools for successful orthodontic and

orthopedic treatments and such variables as chronologi-

cal age, sexual maturity, skeletal growth stages, dental

developmental stages, height and weight have been used

to study the various stages of growth [1], although the

relationship between height, weight and sexual maturity

has not been confirmed yet [2].

If there is a strong correlation between skeletal matur-

ity and dental calcification stages, these stages can be

used as a diagnostic tool for estimating the starting point

of growth. Determination of the patient’s age is also very

important in forensic medicine in criminals or those

without recorded birth certificates both above and below

18 years old [3].

Considering the increased prevalence of obesity, there

is a need for information about its possible effect on

dental development as a part of epidemiological studies

[4].

Body Mass Index (BMI) is a reliable index of over-

weight and obesity in most children and adolescents.

Obesity in children can lead to skeletal problems in the

head and neck region. BMI is dependent on age and

gender in children and adolescents and is generally re-

ferred to as specific for a certain age [5]. Percentage

range of less than 5% is considered as underweight, 5% -

85% normal, 85% - 95% overweight and more than 95%

is overweight. Alteration in the order of teeth eruption

denotes a disorder in normal development of the teeth,

rather than delayed or accelerated growth. The more

time deviation of teeth eruption from normal, the more

possible the presence of a problem in development of

teeth [6].

Panoramic radiographs of developing teeth are used in

various scientific fields for exact assessment of dental

age in order to evaluate maturity and age. In clinical

dentistry, dental age information is used for diagnosis

and planning for treatment. In situations where there is

insufficient information about the identity of the indi-

vidual or correct birth date, dental age can be used to

determine the age of the individual.

Radiological evaluation of the dental age in children is

important for the dentist in order to have a better under-

standing of the dental development. Sometimes when the

exact birth date of the individual is not known, his (her)

M. Zangouei-Booshehri et al. / Health 3 (2011) 253-257

254

somatic maturity rate is used to evaluate th e chronologi-

cal age, but as there is little difference between the den-

tal and chronological age, the evaluation of the rate of

teeth development and formation is more accurate for

determining the historical age than the somatic maturity

[7].

Prabhakaran N. reported that teeth are the most stable

structures in the human body and their developmental

pattern can be used as a reliable technique for estimating

the age of unidentifiable corpses. In this study, dental

age was estimated using various stages of dental devel-

opment based on literature. Radiographic images de-

picting various stages of dental growth could be used for

estimating the chronological age [8].

In studies performed in the fifth and sixth decades of

the last century, there was a weak relationship between

age of erupted teeth and skeletal age. Therefore re-

searches concentrated on the calcification stages of the

teeth [9].

Hilgers and coworkers studied the relationship be-

tween obesity and dental development in children. In

this study 104 children were evaluated by the Demirjian

method. The body mass index was normal in 63 cases,

and 23 and 18 subjects were overweight and obese, re-

spectively. They showed that dental development sig-

nificantly accelerates with increase in body mass index

[10].

Sadeghianrizi studied the relationship between cra-

niofacial development and obesity. In this study, 50 lat-

eral cephalometries were compared and it was reported

that the rate of growth, development and length of cra-

niofacial structures was more in obese individuals. They

also stated that orthodontic treatment in these cases

needs special considerations as their development and

growth speed is more than normal individuals [11].

In the present study, the authors decided to study

whether the increase in BMI is related to acceleration in

teeth eruption or not.

2. MATERIALS AND METHODS

This was a descriptive-analytical study performed by

a cross-sectional method. Children referred to the dental

college of Yazd who needed panoramic radiography for

dentistry treatment entered the study and the develop-

mental state of their teeth (dental age) were evaluated.

Dental age was determined using radiographic images

and developmental stage of the roots. BMI was meas-

ured by dividing the height by the square of the weight.

The difference between the chronological age and dental

age was determined for each sex and in relation to BMI.

A total of 100 children aged between 8 - 12 years were

selected by simple sampling method. After obtaining the

radiographic images, their height and weight was meas-

ured according to the metric standards. Then BMI was

calculated and compared with the respective age and

gender charts .

According to the international BMI standards, chil-

dren with BMI below 5% of standard were considered as

thin or underweight, between 5% - 85% as normal and

above 85% as obese. As the number of samples below

5% of standard was few (only 2 cases), they were in-

cluded in the normal group.

The panoramic radiographic images were taken by a

SE 00810 Planmeca 2002 EC praline machine (Helsinki,

finland). On the basis of Demirjian standard [6], dental

development is related to root development and teeth

eruption according to a known process (Table 1). Dental

age was determined for each case as a single digit num-

ber. Data was segregated on the basis of gender with

dental age of each specimen, chronological age and BMI

of each individual. SPSS was used for analysis and sta-

tistical tests included t test and regression analysis. Level

of significance was set at 0.05.

3. RESULTS

One hundred children entered the study (30 boys and

70 girls). After obtaining panoramic radiographic images

and evaluating the root ends and rate of calcification, the

mean (± standard deviation) eruption age in boys and

girls was 9.796 ± 1.88 and 9.514 ± 1.55, respectively

(Table 1).

In the next stage, Body Mass Index (BMI) of the chil-

dren was calculated and they were divided into two

groups: normal and above normal. 85% of children were

in the normal group and 15% were in the above normal

group (Ta b le 2 ). The mean eruption age was evaluated

separately in each group (Table 3). The minimum and

maximum dental age on the basis of BMI is depicted in

Table 4.

At the end, in order to evaluate the effect of BMI on

eruption age, the difference in mean BMI of various

groups was studied. There was a statistically significant

difference between the mean BMI of two groups (P

value = 0.41).

3.1. Coefficient Ratio between Variables

In order to study the effect of various variables on

growth, coefficient ratio between various variables was

evaluated (Table 5).

4. DISCUSSION

The present study was performed to study the rela-

tionship between dental age and BMI in 8 - 12 year-old

children. Panoramic radiographic images were used to

determine the dental age.

M. Zangouei-Booshehri et al. / Health 3 (2011) 253-257

255255

Table 1. Distribution of children on the basis of gender and

mean eruption age in each group.

Gender Number Mean

Chronological

Age

Mean Eruption

Age Standard

deviation

Boys 30 10.6 9.8 1.88

Girls 70 9.5 9.6 1.55

T = 1.039; P value = 0.488.

Table 2. Distribution of the percentage of children on the basis

of BMI.

Number Percentage

Normal 85 85%

Above Normal 15 15%

Total 100 100%

Table 3. Mean eruption age on the basis of normal and above

normal BMI.

BMI Distribution

Mean Eruption

Age Standard

Deviation

Normal 85 9.5 1.7

Above Nor-

mal 15 10.0 1.8

T = 1.309; P value = 0.301.

Table 4. Minimum and maximum dental age on the basis of

BMI.

BMI Minimum Dental Age Maximum Dental Age

Normal 6 13

Above Normal 12 13

Table 5. Coe fficient ra ti o between various variables.

Dental age Height Weight

Body Mass

Index (BMI)

Coefficient

Ratio 1 0.509 0.436 0.047

Nathile and coworkers stated that awareness about the

growth potential of a patient is on e of the imp ortant too ls

for successful orthodontic and orthopedic treatment and

such parameters as chronological age, gender, stages of

skeletal growth, stages of dental development height and

weight are used to measure stages of growth [1]. In an-

other study by Solhem and coworkers, it was stated that

significant and relatively major differences are present

among children with same chronological age and there-

fore the physiological and biological ages need to be

studied. Physiological age is the speed of progress to-

ward the maturity and can be determined by dental,

skeletal and sexual maturity. Annul increase in height

and weight is the index of physical body maturity.

Nathalie Bosmans and coworkers reported that the use

of panoramic radiographic images is useful for evaluat-

ing dental age and there isn’t any significant difference

between this method and peri-apical and other radio-

graphic techniques [12]. Suhalze and coworkers evalu-

ated the accuracy of panoramic radiographic images and

concluded that horizontal measurements are more reli-

able than vertical ones [13]. Solheim and coworkers

showed that radiographic techniques which estimate the

dental age based on dental morphology are the best

techniques [14]. In the present study, panoramic radio-

graphic images were used to estimate the dental age and

BMI of the children under study was also determined.

Evelyn P stated that the obesity in children and adults is

associated with some complications and the rate of obe-

sity has doubled in the last 25 years [13]. Similarly,

studies have shown that obesity can affect various sys-

tems and bones of the body [15,16]. Considering the

increase in rate of obesity in children with its associated

skeletal and dental complications, the effect of BMI on

dental age was studied in the present study.

Gbstein and coworkers studied the effects of gender

on obesity in children. Obese children usually have less

physical activity which is more prominent in girls and

becomes more apparent with increasing age [17]. As a

result, obesity and increased BMI result in more com-

plications, one of which can be alterations in skeletal and

developmental growth. In the present study, there was a

stronger coefficient ratio between increased BMI in boys

and increased eruption of teeth. The difference can be

related to genetic factors and difference in diet between

Iranian and European children. The present study in-

cluded 100 children (30 boys and 70 girls) with a mean

eruption age of 9.766 in boys and 9.514 in girls, from

which, 85% had normal Body Mass Indices and 15%

had above normal BMI. In Evelyn P study, there was a

double rate of obesity and increased incidence of high

BMI was reported [18].

In the normal BMI group, the mean eruptive age was

9.5176 ± 1.63745, wh ile in the above nor mal BMI group,

it was 10.00 which shows that increased BMI results in

increased eruptive age. In the study by Sudeghrianrizr

and coworkers, it was shown that genetic control is re-

sponsible for 1/3 of the changes in BMI. In obese indi-

viduals, there is a significant reduction in secretion of

growth hormone and as a result, changes in growth hor-

mone secretion can affect the growth of the facial skele-

ton. The radiographic images of obese individuals were

compared with that of normal individuals and results

showed that there were significant differences between

M. Zangouei-Booshehri et al. / Health 3 (2011) 253-257

256

sexes. They also concluded that these growth changes

due to obesity require that alterations be made in den-

tistry treatment plans, especially orthodontic treatments

[11].

Hilgers K. K. studied the effect of children obesity on

dental development and concluded that children with

increase in weight and/or increase in BMI have in-

creased dental development even if they are evaluated in

relation to the age and sex of the child. This increased

dental development is considered as an important vari-

able in pediatric dentistry and orthodontic treatment

[16].

The present study showed that there is a high level of

relationship between chronological and dental age (r =

0.784). Similarly, there was inverse relationship between

height and BMI (r = 1.21). Akinbami and coworkers

studied the role of BMI, mandibular bone and dental

mandibular angle in impaction of the third mandibular

molar teeth. Two factors determining the impaction were

length of the mandible and difference between length of

the alveolar angle and the total measurement of the teeth.

The BMI of each case was measured and it was reported

that prediction of the third mandibular molar teeth im-

paction depends upon two factors: length of the mandi-

ble and difference between the length of the arch and

total dental measurement [19].

Tureli and coworkers studied the relationship between

state of mastication and dental changes and BMI in 97

children aged 8 - 12 years old. The dental state, BMI and

socio-economical status of the population under study

were evaluated and they concluded that children with

normal weight have better mastication compared to chil-

dren with above normal BMI. State of weak mastication

had a significant relationship with decrease in weight

and position of the permanent teeth in children with

normal weight [20].

Sanchez-Perez L. et al. studied the possible associa-

tion between dental caries, and body mass index (BMI)

and the effect of BMI on tooth eruption in a cohort of

elementary school children. They concluded that the

obese childr en had more erupted teeth an d a lower caries

index. The relationship of body composition and oral

health should be considered in pediatric patients [21].

5. ACKNOWLEDGEMENTS

Overweight or obese can accelerate dental development. Accelerated

dental development in overweight children is important to be consid-

ered in pediatric dentistry and orthodontics.

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