Journal of South Asian Association of Pediatric Dentistry
Volume 6 | Issue 3 | Year 2023

Prevalence and Distribution Pattern of Congenitally Missing Maxillary Lateral Incisors among School Children in the Colombo District

Mariesha Perera1https://orcid.org/0000-0002-4082-8510, Priyake D Palipana2https://orcid.org/0000-0002-5077-312X

1Postgraduate Institute of Medicine, University of Colombo, Sri Lanka

2Department of Restorative Dentistry, University of Sri Jayewardenepura, Sri Lanka

Corresponding Author: Mariesha Perera, Postgraduate Institute of Medicine, University of Colombo, Sri Lanka, Phone: +94 755722849, e-mail: pererawmms@gmail.com

Received: 04 August 2023; Accepted: 26 September 2023; Published on: 30 December 2023


Aim and background: Being in the most esthetic region of the mouth, congenitally missing maxillary lateral incisors (CMMLI) tag along with them a unique set of problems. The few global studies done report great racial variation. There is no Sri Lankan study, and even regional data are sparse.

Materials and methods: A cross-sectional study was conducted on 2044 schoolchildren aged 10 years from 20 schools selected randomly in Colombo, Sri Lanka. The screening was done at these schools by a single dentist. Necessary referrals were made to the institute of oral health (IOH) in Maharagama, Sri Lanka. The results were analyzed using Statistical Package for the Social Sciences (SPSS) 21 and presented using descriptive statistical measures.

Results: The overall prevalence of CMMLI was 1.177%, of which 62.5% were in females and 37.5% in males. About 70.8% had a bilateral distribution, whereas 29.2% were unilateral, mostly on the right side. In unilateral cases, the existing one was mainly diminutive. Though it is too early for planning, most cases would tentatively require space closure.

Conclusion: The prevalence of this study was following globally quoted figures of 12%. Further research with larger samples is needed for conclusions.

How to cite this article: Perera M, Palipana PD. Prevalence and Distribution Pattern of Congenitally Missing Maxillary Lateral Incisors among School Children in the Colombo District. J South Asian Assoc Pediatr Dent 2023;6(3):109–113.

Source of support: Nil

Conflict of interest: None

Keywords: Missing lateral incisors, Prevalence, School children


Whatever is said to the contrary, first impressions do count and a pleasing smile is invaluable to the overall presentability of a person. It is well-known and proven that dental appearance is the second most important aspect of facial attractiveness, after the eyes. Missing teeth, in the anterior region, is a challenge to the dentist and cause distress to the patient. Many reasons contribute to missing teeth, such as loss due to caries, periodontal disease, trauma, and congenital absence. Hypodontia, defined as the developmental absence of one or more teeth excluding third molars is one.1 Maxillary lateral incisor is reported to be the commonest missing tooth excluding the third molar. Common problems with congenitally missing maxillary lateral incisors (CMMLI) are spacing, drifting, or rotations of permanent central incisors and canines, a median diastema, the shift of midline in unilateral agenesis, and a peg-shaped counterpart.2 A higher incidence of ectopic maxillary canines has also been observed.3 Common treatment options are space closure, space opening with prosthodontic replacement or autotransplantation of a mandibular premolar. There is no consensus on the best method of treatment. Each option has merits and demerits and must be decided on a case-by-case basis. Early diagnosis and multidisciplinary involvement are of paramount importance, helping to improve the quality of life and plan treatment accordingly to minimize anticipated complications. Data from prevalence studies enable the dentist or the primary dental care personnel to have a reasonable degree of suspicion and make timely referrals.4 Further, prevalence studies may help identify the magnitude of the problem, plan and prioritize treatment, and perhaps even influence the allocation of resources.

The prevalence of CMMLI in previous studies is shown in Table 1. No such research was conducted in Sri Lanka. The minimal number of studies done elsewhere were mainly performed in orthodontic, rather than general populations.

Table 1: Prevalence of CMMLI in previously performed studies
No Year Location Age No of subjects CMMLI
1 2017 Syria 12–15 800 1.1521
2 2016 Dental center at Rumaila Hospital in Qatar 1,045 2.622
3 2016 Dental Hospital in Islamabad, Pakistan 364 patients 1.623
4 2014 Dental Clinic of University in Sains Malaysia 12–16 834 1.724
5 2014 Turkey 2,772 2.2725
6 2013 Center for Aviation Medicine of the Armed Forces of Greece 18.6 ± 0.52 1,745 1.326
7 2012 Faculty of Dentistry of the University of Oporto Portugal 6–15 1,438 2.9227


Ethics Approval and Consent to Participate

The principal investigator discussed with each school principal the study and the benefits to the children [health education, screening for dental disease and appropriate referral to institute of oral health (IOH) Maharagama]. The purpose of the study was explained, and the necessary permission was obtained from the relevant principal. The information sheet was communicated to parents through the school 1 week prior to the research. An opportunity was given to address their queries and concerns by discussing them with the investigators. Written consent was obtained from the parents before the examination of the children, and assent was obtained from the child separately.

Ethical approval was obtained from the Ethics Review Committee of the Faculty of Medicine, University of Colombo.

Study Design

A cross-sectional study.

Study Setting

A 20 randomly selected schools in the Colombo district of Sri Lanka.

Study Participants

Schoolchildren aged 10 years in the above study setting.

Inclusion Criterion

Children aged 10 years from selected schools. The aim was to allow for normal eruption time of lateral incisors, which is 8–9 years.

Exclusion Criteria

Children having missing lateral incisors due to reasons other than congenital absence like extraction/loss due to caries, trauma, or orthodontic treatment.

Sampling Technique

Computerized random number tables were used to select 20 schools from the Colombo district.

Sampling Size

Around 2,044 students from selected schools.

Study Instruments

Data collection sheet filled by the examining dentist.

All students, with parental consent, were examined by a single dentist, the data collection sheet was filled simultaneously and necessary referrals were done. Those with CMMLI were referred to restorative unit B, IOH, Maharagama. A dental panoramic tomogram was taken. Those children who had other dental disease too were referred to the same institute for necessary treatment.

The peg or diminutive upper lateral incisor was defined according to Proffits’ criterion—having lesser mesiodistal width compared to the lower lateral incisor.5

Data Analysis

Statistical analysis was done using Statistical Package for the Social Sciences (SPSS) 21. All the collected data were stored as soft copies and will be destroyed after 5 years. The results were presented using descriptive statistical measures.


Around 2,044 children participated in the study. The prevalence of CMMLI was 1.17% of the affected children, majority (62.5%) were females (Fig. 1).

Fig. 1: Gender distribution of CMMLI. There is a significant female predominance (62.5%)

When missing, the distribution was mainly bilateral (70.8%) (Fig. 2).

Fig. 2: When missing, the distribution was mainly bilateral (70.8%)

Most children had their right lateral incisor missing (71.4%) as opposed to the left (28.6%) (Fig. 3).

Fig. 3: The right lateral incisor was found to be most frequently missing (71.4%)

In unilateral agenesis cases, the remaining lateral incisor was diminutive in size (52.1%) (Fig. 4).

Fig. 4: In unilateral agenesis cases, the remaining lateral incisor was diminutive in size

Tentatively most CMMLI cases would require space closure followed by space opening and other (accept the primary lateral incisor) treatment options (Fig. 5).

Fig. 5: Tentatively most CMMLI cases would require space closure followed by space opening and other (accept the primary lateral incisor) treatment options


Similar to the development of any organ, tooth formation is a precise and delicately controlled process with complex input and interplay between multiple genes, growth factors, and signaling molecules. Thus any disturbance of genetic and/or environmental factors could cause anomalous development or total omission in the formation of teeth. Hypodontia, defined as the developmental absence of one or more primary or secondary teeth excluding third molars, is reported to have a prevalence of 2.6–11.3% worldwide.6

Hypodontia can be isolated and nonsyndromic or part of a syndrome involving ectodermal tissues. CMMLI may occur in the form of an isolated familial or sporadic anomaly or with gene mutation. Other genetic diseases like cleft lip and palate, Downs’ syndrome, hypohidrotic dysplasia, ectodermal dysplasia, Witkop syndrome, holoprosencephaly, incontinentia pigmenti, Van der Woude syndrome, and Rieger syndrome would also lead to hypodontia.7

Numerous studies have assessed the prevalence of congenitally missing teeth among different study populations, as follows. According to a systematic review and meta-analysis done by Khalaf et al., the highest prevalence of hypodontia was found in Africa (13.5%) followed by Europe (7%), Asia, and Australia (6.3%).8 The same systematic review reveals a higher prevalence in females than in males and the most commonly affected teeth are the mandibular premolars followed by CMMLI. However, the results in Asian studies differ, for example, Chinese research reported 5.89% hypodontia prevalence for the general population, while for an orthodontic population, it was 7.48% and the mandibular incisors were the most affected.9

The prevalence and the most common tooth missing are different between races. The upper lateral incisor agenesis affects approximately 2% of the population.10 One study states that excluding third molars, two of every three congenitally missing teeth in oligodontia patients are mandibular second premolars or maxillary lateral incisors.11 A study done for an Arabic orthodontic population in Israel reported the prevalence of CMMLI to be 1.1%.12 An Indian study done for a Bengali pediatric population showed it to be 4.7% of which the most commonly absent was the upper lateral incisor accounting for 28.2% of all missing teeth.13

Since no Sri Lankan study was done in this respect, it was useful to identify the prevalence as a significant variation is described in India and the region. CMMLI represents 14–44% of the total missing teeth, as shown in Table 2. The therapeutic management of CMMLI is a complex and challenging process.14

Table 2: Distribution of CMMLI as a percentage of all missing teeth among various populations
No Year Country No. of subjects Affected people Total missing teeth CMMLI % of the total missing teeth
1 2014 Sudan 2,401 64 100 19 1928
2 2013 Romania 947 136 60 44.129
4 2012 Turkey 1,291 80 135 21 15.530
5 2011 Germany 1,353 171 693 103 14.931
6 2010 Iran 600 54 94 25 26.632
7 2009 Denmark 8,138 601 1,070 212 19.833
8 2009 Jordan 1,726 123 197 88 44.534

Selecting a descriptive study design was most appropriate here. Using a single operator is a strength since inter-operator bias is not present. However human error caused by exhaustion of the sole operator is an inevitable limitation.

The study reveals a relatively low prevalence of CMMLI (1.17%) compared to the ones conducted worldwide. Nevertheless, it is in par with the lower prevalence in Asian populations.13 The overall prevalence of hypodontia in a recent Indian study was observed to be 1.4% (as opposed to other Indian studies indicating 4–16%) and the most frequently missing tooth was the maxillary lateral incisor (44.54%).15

A significantly higher prevalence in females (62.5%) was noted, as advocated in some previous systematic reviews. Many studies suggest that there is a strong genetic influence and a higher prevalence in females.16,17 Our study reveals bilateral incidence to be 70.8%. When a single side is affected it is commonly on the right side (71.4%). All these findings are important to diagnose CMMLI early and do a timely intervention to prevent possible complications. Prompt diagnosis and careful evaluation of treatment determinants through a multidisciplinary approach are essential for the proper management of clinical problems.18 CMMLI may have other associated dental anomalies such as other missing teeth, peg lateral incisors, or potential impactions, and especially maxillary canines.19

When there is a unilateral CMMLI the contralateral existing tooth is diminutive in 52.1% of cases in this study. This was evident in previous studies including the one by Pinho et al., where they found peg laterals were more significantly frequent in their first group (subjects with agenesis of one or both permanent maxillary lateral incisors), supporting the theory that microdontia is a variable expression of the same developmental disturbance that causes tooth agenesis.3 A diminutive sized tooth challenges treatment as simultaneous creation of more space for it and matching esthetics to the opposite side are needed. It is necessary to assess the possibility of building up the diminutive tooth, if not to accept it as it is, or extraction and subsequent management. Thus it is all-important in identifying the incidence and associated presentations in a population in planning treatment and identifying the possible challenges in treatment. One paper proposes a diagnostic protocol (including facial aspects, dental and functional aspects, and periodontal considerations) providing a meticulous and consistent evaluation for patients with absent maxillary lateral incisors facilitating treatment planning and the communication between professionals, patients, and families.19

Even though the prevalence rates take a relatively low value ranging from 1 to 2%, it translates to one in 50 children or several hundreds of thousands of children. Replacing developmentally missing teeth would not be the same as doing so for loss of existing teeth due to caries, periodontal disease, or trauma. Having at least a partial genetic component, many other associated abnormalities may coexist with hypodontia, both dental as well as in other systems. As the human genome gradually unravels, many new associations between genetic anomalies are discovered. It has been proposed that tooth agenesis and cancer development could share common molecular pathways.20 Here again, is an example that oral health is not discrete from general health, and the dental surgeon has an important role to play more than ever before. All these highlight the importance of early detection of hypodontia, including CMMLI.

Clinical Significance

Being the first study in Sri Lanka, it is recommended to consider these findings as the baseline and carry out similar studies more comprehensively on other geographically varied populations, representing the whole Island.

Limitations of the Study

Considering only one district and a limited sample are limitations of this study. More research is needed with a larger sample size representing all districts of the country.


Competing Interests

The authors declare that they have no competing interests.


WMMSP (guarantor) and PDP were responsible for the study’s concept, design and preparation, questionnaires, and information sheets. The fieldwork, and analysis were done by WMMSP and PDP revised it critically for important intellectual content as well as read and approved the final manuscript.


With much gratitude:


Mariesha Perera https://orcid.org/0000-0002-4082-8510

Priyake D Palipana https://orcid.org/0000-0002-5077-312X


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