Determination of the Combined Mesio-distal Widths of the Permanent Mandibular Incisors and that of the

Maxillary and Mandibular Canines and Premolars in a Group of Egyptian Children in Suez Governorate:

A Cross-sectional study

Thesis Submitted to

Faculty of Dentistry - Cairo University

In partial fulfillment of the requirements for Master

degree in

Pediatric Dentistry

By

Hagar Mohamed Ahmed Hassan AbozeidB.D.S. Ain Shams University (2010)

Dentist at Badr CityMinistry of Health and Population

Faculty of DentistryCairo University

2018

SUPERVISORS

Ass. Prof. Dr. Manal Ahmed El-SayedAssociate Professor of Pediatric Dentistry and Dental

Public Health, Faculty of Dentistry

Cairo University

Ass. Prof. Dr. Manal Ahmed El-SheikhAssociate Professor of Pediatric Dentistry and Dental

Public Health, Faculty of Dentistry

Cairo University

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The Judgment Committee

Ass. Prof. Dr. Adel Abd El-Azim El-Bardisy

Associate Professor of Pediatric Dentistry and Dental

Public Health, Faculty of Dentistry

Cairo University

Prof. Dr. Nagwa Mohamed AliProfessor of Pediatric Dentistry and Dental Public

Health, Faculty of Dentistry

Menia University

Ass. Prof. Dr. Manal Ahmed El-SayedAssociate Professor of Pediatric Dentistry and Dental

Public Health, Faculty of Dentistry

Cairo University

Ass. Prof. Dr. Manal Ahmed El-SheikhAssociate Professor of Pediatric Dentistry and Dental

Public Health, Faculty of Dentistry

Cairo University

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ABSTRACTDetermination of the Combined Mesiodistal Widths of the

Permanent Mandibular Incisors and that of the Maxillary and Mandibular Canines and Premolars in a Group of Egyptian Children in Suez Governorate:A Cross-sectional study

Hagar Mohamed Abozeid*, Manal Ahmed El-Sayed** and Manal Ahmed El-Sheikh***

Abstract:Background: Tooth size specifically the mesiodistal dimension has an important role in normal occlusion and in arch space analysis as it affects treatment planning and the final results in orthodontic treatment. Tooth size differs among and within populations. It is affected by both genetic and environmental factors.

Objectives: The aim of the current study was to measure the mesiodistal widths of the mandibular incisors, maxillary and mandibular canines and premolars in a group of Egyptian children in Suez Governorate and to correlate between the widths of these teeth to formulate normative data for the Egyptian children.

Materials and Methods: 12-15 year old children (150 boys and 150 girls) from Suez Governorate were included in the present study. The measurements of the mesiodistal widths of the teeth were conducted on dental casts by a digital caliper

Results: The means of the mesiodistal widths of the boys’ teeth were significantly larger than those of the girls. Also, there was no statistically significant difference between the right and left sides in girls. However, in males the right mandibular second premolar was significantly bigger than the left side.

Conclusion: Sexual dimorphism is present between boys and girls where boys had larger teeth than girls. There were no statistically significant differences between the right and left sides in girls. But in boys only the mandibular second premolar showed slight statistically significant difference. The mandibular permanent incisors can be used in the prediction of the mesiodistal widths of the maxillary and mandibular permanent canines and premolars due to positive correlation between them.

* B.D.S Ain Shams University (2010)** Associate Professor of Pediatric Dentistry and Public Health Department, Faculty of Dentistry, Cairo University.** Professor of Pediatric Dentistry and Public Health, Faculty of Dentistry, Cairo University.

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INTRODUCTION

The mesiodistal width of a tooth is defined as the distance between

the two parallel lines, which are perpendicular to the mesiodistal axis of

the tooth tangential to the most mesial and the most distal points of the

crown along a parallel line to the occlusal plane. (Hasegawa, 2014)

Tooth size specifically the mesiodistal dimension has an important

role in normal occlusion and in arch space analysis as it affects treatment

planning and the final results in orthodontic treatment (Memon and

Fida, 2012).

Tooth size differs among and within populations. It is affected by

both genetic and environmental factors. Contributing factors include race,

sex, hereditary, environment, secular changes and bilateral asymmetry.

Environmental factors as nutrition, health conditions and climate affect

the dentition prenatally (Esnaashari et al, 2014).

Malocclusion is a common esthetic and functional problem in the

world. It's a developmental condition caused by alteration in normal

development (Jahan & Hossain, 2011).

The majority of malocclusion, which starts during the mixed

dentition period, can be treated and eliminated in its severity if it was

managed early (Felicio et al, 2010).

Early diagnosis and treatment of malocclusion is important in

orthodontics. For this reason, accurate arch space analysis is needed to

determine the appropriate treatment that may include space maintenance,

space regaining, and guidance of eruption, serial extractions or periodic

check-ups of the patient (Kundi et al, 2012 and Abdelbagi et al, 2016)

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Arch length analysis is the prediction of the meisodistal widths of

the un-erupted permanent canines and premolars to detect the discrepancy

between the available and required spaces. It is of great importance in

determining and handling the developing occlusion of growing children.

Since it will aid in figuring out if the posteriorly available space is

adequate for the good alignment of the permanent teeth or not (Memon et

al, 2012 and Abdelbagi et al, 2016).

Arch space analysis can be done either through:

Radiographs

Prediction tables

Or both (Burhan and Nawaya, 2014).

To this date, few studies on the mesiodistal dimensions of teeth of the Egyptian population were found in the literature. For that reason, this study was carried out as part of a project adopted to gather data from

different Governorates in Egypt on the mesiodistal widths of the permanent mandibular incisors, maxillary and mandibular canines and

premolars. This will help in ra

AIM OF THE STUDY

The aim of the study was to:

I. Determine the combined mesiodistal widths of the permanent

mandibular incisors and that of the maxillary and mandibular right

and left canines and premolars in a group of Egyptian children in

Suez Governorate.

II. Correlate the mesiodistal widths of the permanent mandibular

incisors to that of the maxillary and mandibular right and left

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canines and premolars to formulate normative data for the Egyptian

children.

MATERIALS AND METHODS

As a cross-sectional study was planned, in which multiple regression analyses were performed with 20 independent variables, the expected multiple regression coefficient was estimated to be R=0.50. In this study, 300 subjects needed to be recruited with Probability of Type I Error (α)= 0.05 and power= 90.0% (VanVoorhis et al., 2001). 150 females and 150 males were selected from Nabwia Moussa Preparatory Mixed School in Suez Governorate. The ethical committee in Faculty of Dentistry, Cairo University approved this study. A permission letter that explains the aim of the study was presented to the head of the educational region for his approval to enter the governmental schools. A written consent was given to the school’s principal in charge of the subjects, who were included in the study to sign before the beginning of the procedure.

Inclusion Criteria:

Age: 12-15 years. Full set of permanent dentition from left first permanent molar to right first permanent molar in the upper and lower arch. No apparent orthodontic problem. No previous history of orthodontic treatment. No clinically apparent proximal caries, crown fractures, malformed teeth, interproximal restorations or any dental anomalies. No apparent systemic conditions or genetic syndromes (medically free) that may affect the mesiodistal dimensions of the included teeth.

Exclusion Criteria:

Missing permanent teeth or retained primary ones. Dentition exhibiting morphological anomalies. Crowding, rotation, increased overjet or any other orthodontic condition.Patients were divided into two groups according to gender (150 boys and 150 girls).

Materials:

The materials used were:

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1. Disposable diagnostic sets.2. 150 pairs of perforated stock metal trays size 1*3. Multiple rubber bowls and spatulas.4. Irreversible hydrocolloid impression material**. 5. Hard dental stone***.6. Digital Caliper with a calibrated digital micrometer****, read to the nearest 0.01mm used to measure the tooth size.

*Misr Dental-Egypt**Tropicalgin impression material-Zhermack-Italy***HTM Dent-Turkey****ELORA, Germany

Method:

1. Clinical examination:

A diagnostic chart was made for each student including medical and dental history. Dental examination was made on a student’s bench in the classroom using a disposable diagnostic set that includes a mouth mirror and a probe.

Examination procedures:

A. Impression taking:

Impressions of both the upper and lower arches were taken by fast setting irreversible hydrocolloid impression material (Tropicalgin impression material-Zhermack-Italy) using suitable size perforated study trays. The material was used according to the manufacturer’s instructions regarding mixing and setting time. The impressions were rinsed under running water, wrapped with moist gauze and placed in a polyethylene bag with the student’s name written on the bag until it was poured.

B. Study casts and model trimming:

Each impression was poured within one hour using dental stone to avoid any dimensional changes. The stone was mixed according to the manufacturer’s instructions. The casts were trimmed at Digital Dental Academy laboratory.

C. Measurements taken from the study casts:

Measurements were taken perpendicular to the long axis of the tooth, with a digital caliper entering the interproximal area from the anatomic

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mesial contact point to the anatomic distal contact point of each tooth parallel to the occlusal plane (Priest & Hunter, 1960). All the dimensions were measured directly from the study models using a digital caliper especially designed for dental use.The measurements were recorded in excel sheets to the nearest 0.01mm.The following measurements were recorded from each cast for each student: Mesio-distal width of the four mandibular incisors. Mesio-distal width of the mandibular right canine, first and second premolars. Mesio-distal widths of the mandibular left canine, first and second premolars. Mesio-distal width of the maxillary right canine, first and second premolars. Mesio-distal widths of the maxillary left canine, first and second premolars.

Measuring Device:

According to the manufacturer’s instructions, the digital caliper simplified the reading of the value from the display. The display could be switched from ‘millimeter’ to ‘inches’ and had the function of zeroing the

display at the beginning or anywhere along the slide. The slide of the digital caliper may also be controlled through thumb roller or locked

using a thumbscrew. The readings were displayed to the nearest 0.01mm

REVIEW OF LITERATURE

Teeth development starts in the intrauterine life. Their size is

controlled by hereditary factors and is usually unaffected by external

factors but if subjected to infection, trauma or pathological condition,

hypoplasia or hyperplasia may be expected (Hussein et al, 2009).

Mesiodistal crown diameter, which is also known as tooth size,

tooth crown size or tooth width in human populations is an important

focus in many studies as it can be used in forensic investigations, human

evolution, biological issues and clinical dentistry. In clinical dentistry, the

relationship between the mesiodistal crown diameter and arch alignment

is important to determine malocclusion and crowding as a correct

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mesiodistal crown diameter relationship between the upper and lower

teeth is essential for proper inter-digitation, over-jet and overbite in final

orthodontic treatment (Hattab, 2013).

Tooth size implies to the mesio-distal widths of the upper and

lower teeth. Certain relationships should be present between the

dimensions of the upper and lower teeth to provide adequate inter-

digitation, overbite and over-jet (Batool et al, 2008).

Tooth size discrepancy is the disproportion in the sizes of the teeth.

It’s usually limited to a single tooth such as peg lateral incisor (Batool et

al, 2008).

Moorres and Reed (1954) proposed the most commonly used

method for tooth size determination. Mesiodistal tooth size is defined as

‘the greatest distance between the contact points of the proximal surfaces

of the dental crown, with the calipers parallel to both the occlusal and

vestibular surfaces.

The mesiodistal dimension of the permanent teeth is essential in

orthodontic diagnosis and treatment planning, and its also considered as an

important aspect in space analysis, treatment planning and orthodontic

treatment to reach normal occlusion (Hashim et al, 2005 and Al-Janabi,

2005).

The mesiodistal dimensions of both the upper and lower teeth

should be in appropriate balance as they greatly affect posterior inter-

digitation, overbite and over-jet in centric occlusion. The mesiodistal

dimension should also be in balance with the arch size for appropriate

alignment (Hashim and Al-Ghamdi, 2005).

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Comprehensive orthodontic treatment’s essential purpose is to

achieve ideal occlusion, overbite and over-jet where tooth size

discrepancies of the maxillary and mandibular arches play a crucial role.

It’s hardly possible to reach ideal occlusion if there is tooth size

discrepancy (Lopatiene et al, 2009).

For the orthodontist to determine functional and esthetic results of

cases, the determination of tooth size discrepancies is an essential

diagnostic tool (Hashim and Al-Ghamdi, 2005).

The size of the permanent teeth can’t be estimated on the basis of

the size of the primary teeth as their sizes are inherited separately

(Janosevic et al, 2006).

Tooth size and shape varies from one person to another, from

males and females and from one ethnic group to the other depending on

genetic factors (Moon et al, 2006).

Sexual dimorphism:

Sexual dimorphism is the differences in the size or shape of teeth

between males and females of the same species (Bunger et al, 2014).

Environment and genetics both affect tooth size and it’s strongly

linked to sex and ethnicity. Males’ teeth are larger in size than those of the

females and Africans have larger teeth than Europeans (Altherr et al, 2007).

Sexual dimorphism in different races:

China:

In a study of four hundred and fifty nine subjects (295 males and

164 females), the mesiodistal crown dimensions of all erupted permanent

incisors, canines and premolars were measured using a digital caliper. It

was concluded that sexual dimorphism existed between Southern

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Chinese males and females in incisors, canines and premolars and new

linear regression equations were formulated (Ling and Wong, 2006).

Turkey:

In a study of four hundred and fifty dental casts with mean age

15.25-+ 1.25 that were chosen from the records of the patients at the

Department of Orthodontics of Selcuk University, Faculty of Dentistry,

Konya, Turkey to formulate new regression equations for the mixed

dentition analysis. It was found out that males had larger teeth than

females. There was no significant difference between the right and left

sides. Both Moyers and Tanaka and Johnstons’ analyses can’t be applied

on the Turkish population and new equations were formulated (Uysal et

al, 2009).

Yemen:

A sample of one hundred and seventy six subjects (82 males and 94 females) with an age range (13-25) was used to study the mean mesiodistal widths and possible sex differences among Yemeni

population. The sample selected had different types of malocclusions (94 Angle Class I, 37 Class II division 1, 36 Class II division 2 and 9 Class

III). The mesiodistal widths were measured using digital caliper on

dental casts. The results showed that males had significantly larger teeth

than females and also there were no significant differences in the

mesiodistal teeth widths between the right and left sides (Al-Gunaid et

al, 2012).

Malocclusion:

It is a considerable deviation from the ideal occlusion caused by

differences in the size and location of the teeth and their arches and also

the facial bones and soft tissues. Malocclusion isn’t a healthy or a disease

condition (Hassan and Rahimah, 2007).

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Malocclusion may be represented as either:

Mal-alignment in the same arch: of a tooth or more in the same

arch. The tooth may show rotation, tipping, displacement, infra-

occlusion, supra-occlusion or transposition.

Mal-relationship of the dental arches: in relation to normal

occlusion. Its may happen in any of the three planes: antero-

posterior, vertical or transverse (Hassan and Rahimah, 2007).

Malocclusion, a developmental condition, is one of the common

esthetic and functional problems present. Malocclusion results from

distortion of normal development (Jahan and Hossain, 2011).

It mostly occurs due to imbalance between the size of erupting

permanent teeth and the available space in the arch (Adnani et al, 2011).

It is also defined as any variation from normal occlusion, which is

mainly due to the difference between the size of teeth and the size of their

arches (Butt et al, 2012).

Tooth size differences in different races:

A study was carried out to compare the mesiodistal crown

dimensions in three populations from Egypt, Mexico and United States.

The sample consisted of 54 Egyptian subjects (30 males and 24 females),

57 subjects (35 males and 22 females) from Iowa, United States and 60

subjects (26 males and 34 females) from

Mexico. All subjects had normal class I occlusion with no history

of orthodontic treatment. The results showed that there was a

difference in the mesiodistal dimensions between the three

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populations. Also, there was sexual dimorphism where males had

larger teeth than females among each population especially in the

canines and premolars and finally there was no statistical

significance between the right and left sides for all populations

(Bishara et al., 1989).

Fifty four Dominican American orthodontic patients (36 men and

18 women) were chosen to conduct a study to form normative data

of the mesiodistal dimensions of the permanent dentition in the

Dominican Republic and to compare the results obtained with those

of previous studies and also compare it with similar studies

obtained on African American and North American white

populations. It was concluded that sexual dimorphism exist. In

addition, the data were similar to those of previous study and that

the data for the Dominican American are close to those of the

African Americans and smaller than that of the North Americans

(Santoro et al, 2000).

In another study that was carried out by measuring the mesiodistal

widths of the teeth of Caucasian, African, Japanese individuals with

Brazilian ancestry on dental casts using a digital caliper and

compared with each other. The sample consisted of 30 Caucasian

individuals, 40 Africans, and 30 Japanese with mean age 15-16

years old. All subjects showed normal occlusion and not previous

orthodontic treatment. It was concluded that Africans had larger

mesiodistal widths followed by the Japanese and then the

Caucasians (Fernandes et al, 2013).

Arch length analysis in different countries:

Saudi Arabia:

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Al-Khadra study was used to study the prediction of the

mesiodistal width of the un-erupted canines and premolars in Saudi

population. He concluded that 35% confidence level in Moyers analysis

was more precise than the 75% confidence level and that Tanaka and

Johnston equations over-estimated the size of the buccal part in Saudi

people. So further studies were needed to formulate new equations and

compare results with other studies.

Another study was carried out where dental casts of sixty-five

subjects (37 males and 28 females) were collected to predict the size of

the un-erupted canines and premolars in Saudi population. Using an

electronic digital caliber to measure the mesiodistal widths of teeth of

both arches from the left first permanent molar to the right first

permanent molar. It was concluded that, when both sexes combined the

50% confidence level of the canines and premolars is more precise. This

differs from Al-Khadra conclusion because he didn't take into

Jordan:

The reliability of both Moyers and Tanaka and Johnston’s analyses

were investigated in Jordanian population. A sample of one hundred and

thirty males and sixty-five females between the ages of 14 – 16 years was

collected. The mesiodistal widths of the lower permanent incisors and the

maxillary and mandibular canines and premolars were measured using a

digital vernier caliper. It was found out that there is a difference between

the sum of the mesiodistal widths of the canines and premolars between

males and females. It was also found out that Moyers analysis could be

used at probability levels 65% and 75% for Jordanian population. Tanaka

and Johnston’s equations aren’t precise and can’t be used for the

Jordanian population. New regression equations were formulated. (Abu

AlHaija and Qudeimat, 2006)

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Syria:

A study of six hundred and seventy sets of dental casts (342

females and 328 males) was performed to determine the applicability of

both Moyer’s and Tanaka and Johnston analyses in Syrian population.

The measurements were made using an electronic digital caliper. It was

found out that Moyer’s analysis was more accurate for Syrian

population but the correct percentile should be used according to gender

because at the 50% percentile levels, it underestimated the actual values

in males but were comparable with that of the females. While in the 75%

percentile levels it overestimated the actual values in the females but was

comparable with the males. In Tanaka and Johnston’s equations, new

equations were formulated. (Burhan and Nawaya, 2014)

SUMMARY

This study was conducted to measure the mesio-distal widths of the

mandibular incisors, maxillary and mandibular canines and premolars in a

group of Egyptian children in Suez Governorate and to correlate between

the widths of these teeth to formulate normative data for the Egyptian

population.

The sample included 300 students (150 males and 150 females) in

the age range of 12 to 15 years from Nabwia Moussa mixed preparatory

school in Suez Governorate.

The measurements of the mesio-distal widths of the teeth were

done on dental casts by a digital caliper, which was held perpendicular to

the long axis of the tooth, after taking alginate impressions of the upper

and lower arches and pouring dental casts using dental stone.

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The results of this study showed that; the means of the mesio-distal

widths of the boys’ teeth were significantly larger than those of the girls.

Also, there was no statistically significant difference between the right

and left sides in girls. However, in males the mandibular second premolar

showed statistically significant difference between the right and left sides.

There was positive significant correlation between the mesiodistal

widths of upper right canine and premolars & the mesiodistal widths of

the lower incisors in both boys and girls. Futhermore, there was positive

significant correlation between the mesiodistal widths of upper left canine

and premolars & the mesiodistal widths of the lower incisors in both boys

and girls.

It was also concluded that there was positive significant correlation

between the mesiodistal widths of upper right canine and premolars & the

mesiodistal widths of the upper left canine and premolars in both boys

and girls. There was also a positive significant correlation between the

mesiodistal widths of lower right canine and premolars & the mesiodistal

widths of the lower left canine and premolars in both boys and girls.

And finally, the results showed that there was positive significant

correlation between the mesiodistal widths of lower left canine and

premolars & the mesiodistal widths of the lower incisors in both boys and

girls. Besides, there was positive significant correlation the mesiodistal

widths of lower right canine and premolars & the mesiodistal widths of

the lower incisors in both boys and girls.

CONCLUSIONS

Based on the results of this study the following was concluded:

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1. The presence of sexual dimorphism between boys and girls where

boys had larger teeth than girls.

2. No statistically significant differences between the right and left

sides in girls so clinicians can rely on the mesiodistal teeth widths

of one side if the other side is missing.

3. No statistically significant differences between the right and left

sides in boys except for the mandibular second premolar.

4. Positive significant correlation is present between the mesiodistal

widths of the mandibular permanent incisors and the mesiodistal

widths of the maxillary and mandibular permanent canines and

premolars, which allows the mandibular permanent incisors to be

used in their prediction.

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