Dental Agenesis

Introduction

Various definitions are used to describe the phenomenon

of congenitally missing teeth: hypodontia,

oligodontia, anodontia, congenitally missing

teeth and dental agenesis. Anodontia stands for

patients with complete absence of teeth, oligodontia

for patients with the absence of six or more

teeth, apart from the third molars (1). The authors

prefer the term dental agenesis as it describes more

accurately the developmental disorder involved.

Large differences in the prevalence of dental

agenesis have been reported, varying from 0.3

(2) to 36.5% (3). The relationship between the

prevalence of missing teeth and dental consumption

seems obvious. The actual number of dental

agenesis in a community is therefore not only

interesting for dentists but also for public health

departments and health insurance companies. In

most studies the sample size is too small to reach

valid conclusions regarding the distribution of

agenetic teeth for gender and site. The data

presented in the literature have not been analyzed

by an integrated approach. The aim of this study is

to increase the insight in the prevalence of dental

agenesis and its implication for dental consumption

in communities by the method of metaanalysis

(4, 5). In addition, meta-analysis enables

Community Dent Oral Epidemiol 2004; 32: 217–26

All rights reserved

Copyright
Blackwell Munksgaard 2004

A meta-analysis of the

prevalence of dental agenesis

of permanent teeth

Polder BJ, Van’t Hof MA, Van der Linden FPGM, Kuijpers-Jagtman AM.

A meta-analysis of the prevalence of dental agenesis of permanent teeth.

Community Dent Oral Epidemiol 2004; 32: 217–26.
Blackwell Munksgaard,

2004

Abstract – Objective: To gain more insight into the prevalence of dental

agenesis. Methods: Data from Caucasian populations in North America,

Australia and Europe were included in a meta-analysis. For the prevalence of

African American, Chinese and Arab groups only indications could be reported

because of a limited number of studies. Results: Agenesis differs by continent

and gender: the prevalence for both sexes was higher in Europe (males 4.6%;

females 6.3%) and Australia (males 5.5%; females 7.6%) than for North

American Caucasians (males 3.2%; females 4.6%). In addition, the prevalence of

dental agenesis in females was 1.37 times higher than in males. The mandibular

second premolar was the most affected tooth, followed by the maxillary lateral

incisor and the maxillary second premolar. The occurrence of dental agenesis

was divided into three main groups: common (P2i > I2s > P2s), less common

(I1i > I2i & P1s > Cs & M2i) and rare (M2s & M1s > Ci > M1i & I1s). Unilateral

occurrence of dental agenesis is more common than bilateral occurrence.

However, bilateral agenesis of maxillary lateral incisors is more common than

unilateral agenesis. The overall prevalence of agenesis in the maxilla is

comparable with that in the mandible, but a marked difference was found

between both jaws regarding tooth type. Absence of one or two permanent

teeth is found in 83% of the subjects with dental agenesis. A practical

application of the results of the meta-analysis is the estimation of dental

treatment need.

Bart J. Polder1, Martin A. Van’t Hof2,

Frans P. G. M. Van der Linden1 and

Anne M. Kuijpers-Jagtman1

Departments of 1Orthodontics and Oral

Biology, and 2Cariology and Preventive

Dentistry, University Medical Centre,

Nijmegen, The Netherlands

Key words: dental agenesis; meta-analysis;

prevalence

Bart J. Polder DDS, Department of

Orthodontics and Oral Biology, University

Medical Centre Sint Radboud, PO Box 9101,

6500 HB Nijmegen, The Netherlands

Tel: +31 243 614 005

Fax: +31 243 540 631

e-mail: orthodontics@dent.umcn.nl

Submitted 13 May 2002;

accepted 5 November 2003

217

the study of determinants such as gender, site and

race for the prevalence and more reliable predictions

of dental consumption because of the number

of teeth to be replaced.

Materials and methods

Source of material, inclusion and

exclusion criteria

In November 2002 a literature search of prevalence

reports on dental agenesis, catalogued in Medline,

Silverplatter and EMBase, was conducted with the

key words ‘hypodontia’, ‘oligodontia’, ’anodontia’,

‘agenesis’ and ‘prevalence or incidence’. Papers

dealing with patients with craniofacial syndromes

or developmental disorders were excluded. After

this search 125 papers remained. Two independent

observers (BP and AK) rated these papers according

to the following criteria.

The inclusion criteria were:

• Presence of an English abstract

• Sample is representative for the underlying

general population

• Diagnosis ‘dental agenesis’ based on a radiographic

examination

• Report presents information on the ethnic background

• Report presents prevalence of agenesis except

third molars

The exclusion criteria were:

• Study limited to an orthodontic patient group, or

patient groups with craniofacial syndromes or

developmental disorders

• Isolated populations were regarded as non-representative

• Incomplete radiographic examination

• Report with no proper data analysis

• A second report on the same population

An excellent interobserver agreement was

obtained (inter-observer kappa ¼ 0.96) and 35 publications

were included. Furthermore, literature

references in the 125 papers reporting on prevalence

of hypodontia were checked. The result of this

manual search was 16 papers.

The concerning 51 publications are presented in

the reference list (6–56). The next step was a

thorough evaluation of the whole text of these

papers by the same two observers.

From the 35 computer searched papers 19 were

excluded, from the 16 manual searched papers one

was excluded, resulting in a total of 31 papers

(inter-observer kappa ¼ 1.00).

Populations in the meta-analysis

...