736 2024


The Prevalence of Par.al Edentulism and Associated Factors: A Cross-Sec.onal Study   
 

Vol 13 No 2 (2024)    DOI 10.5195/d3000.2024.736 

 h#p://den*stry3000.pi#.edu 

The Prevalence of Partial Edentulism and Associated Factors: 
A Cross-Sectional Study 
 
Ruaa Hameed Karadi, Ghufran Dhari Awad, Zainab Mahmood Mansi, Ahmed Abed Marzook 

 Dijlah University College, Baghdad, Iraq 

 

Abstract 

Objec&ve: The current study aimed to determine the prevalence of par5al edentulism according to 
Kennedy’s classifica5on and its associa5on to arch, age and gender. 

Methods: Data were collected from 358 pa5ents aged 18 to 80 years. Selected pa5ents were grouped 
according to gender and age (<45, =>45). Intra oral examina5on for each pa5ent was done. The paLern 
of par5al edentulism according to Kennedy’s classifica5on was determined. Sta5s5cal analysis was done 
using the SPSS V26 sta5s5cal program. Chi-square test was used to test for differences in frequency at 
p-value<0.05. 

Results and Conclusion: The rate of class III paLern in maxillary arch was significantly higher than that 
of mandibular arch. Class I paLern in mandibular arch was significantly higher than that of maxillary arch 
(25.1% vs 14%, P=0.001). No differences in frequency were found between class II and IV paLern and 
affected arch. Class IV was the least frequent in both dental arches. Frequency of class I and class II par5al 
edentulism increased with age, while class III was more frequent at young age. Class IV paLern was more 
frequent among males than females. 

Keywords: Par5al edentulism, Kennedy 
classifica5on, Gender differences, Sex 
differences, Dental arches.  

 
Cita;on: Karadi RH, et al. (2024) The Prevalence of 
Par;al Edentulism and Associated Factors: A Cross-
Sec;onal Study  
Received: September 21, 2024 
Accepted: September 30, 2024 
Published: October 8, 2024 
Copyright: ©2024 Karadi RH, et al. This is an open access 
ar;cle licensed under a Crea;ve Commons AXribu;on 
Work 4.0 United States License. 
Email: drzainabmansi2009@gmail.com

Introduction 

The physiological, social, and 
psychological aspects of the 
quality of life associated to oral 
health are greatly affected by 
tooth loss. It causes a variety of 
anatomical, aesthetic, and 
biomechanical problems that 
compromise a person's general 
health and quality of life [1]. In 
several countries during the past 
few decades, the prevalence of 
tooth loss has significantly 
decreased [2-4]. The decrease in 
the number of edentulous people 
is an indicator that oral health in 

the population is improving [5,6], 
and it also indicates that the 
health care system's preventive 
measures were effective [2,7]. 

When some natural teeth are lost, 
but not all of them, then partial 
edentulism or a gap or space in 
the dental arch that can be 
replaced by one or more teeth is 
established. Caries, periodontal 
disease, trauma, impactions, 
supernumerary teeth, neoplastic 
and cystic lesions are the most 
common causes [8,9]. 

There are numerous classifications 
for partial edentulism, but the 
most popular ones are Cummer, 
Neurohr, Kennedy, Applegates, 
Skinner, and Bailyn [10,11]. 
Kennedy's classification for 
partially edentulous arches is 
currently regarded as the most 
frequently accepted classification. 
Kennedy's classification provides 
quick visualization, prosthesis 
support identification, and 
evaluation of removable partial 
denture design elements [12-14]. 
Kennedy classified all partially 
edentulous arches into four major 
types. They are: Class I, posterior 



The Prevalence of Par.al Edentulism and Associated Factors: A Cross-Sec.onal Study   
 

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to the remaining natural teeth, 
bilateral edentulous regions; Class 
II, a single edentulous region that 
is posterior to the natural teeth 
that are still present; Class III, an 
area that is unilaterally edentulous 
but still has natural teeth on each 
side of it and, Class IV, a single, 
bilateral (across the midline) 
edentulous area that is anterior to 
the remaining natural teeth [15]. 
Class III has been reported as the 
most common pattern in maxillary 
arch, while class IV the least 
common [16]. Also, Kennedy type 
III was the most common kind of 
classification in both the maxilla 
and the mandible, whereas 
Kennedy type IV was found to be 
the least common in the maxilla 
and in the mandible [17]. Class I 
and class II tend to increase with 
age while class III and class IV tend 
to decrease [16,18]. Most authors 
have concluded that there are no 
significant differences in partial 
edentulism by gender [19]. 

This study's objective was to 
establish the frequency of partially 
edentulous patients within Iraqi 
population by age, gender, and 
arches. 

 Material and Methods 

This cross-sectional study was 
conducted at Dijlah University 
Dental Hospital, Iraq, Baghdad, 

where patients treated at the 
Prosthodontics Department to 
restore missing teeth with 
removable partial denture were 
selected. 

This study extended from October 
2021 to May 2022. Each adult 
patient having partially edentulous 
spaces was interviewed and data 
on age, gender, number of teeth, 
site of missing teeth, and pattern 
of partial edentulism according to 
Kennedy’s classification were 
collected. The study excluded 
patients who had only missing 
third molars, unerupted or 
congenitally missing teeth, 
retained roots, and mobile teeth 
that needed to be extracted. In 
cases of patients having complete 
edentulism were also not 
included. 

Ethical consideration 

The Dijlah University Dentistry 
Department's ethics and research 
committee thoroughly evaluated 
and approved the project. Each 
patient was given a written 
consent after being fully informed 
of the study's objectives and 
receiving assurances regarding the 
confidentiality of the data that 
would be collected, which would 
be anonymous and utilized only 
for the current study. 

Statistical analysis  

The statistical program SPSS V26 
was used to analyze data. Chi-
square was used for all 
comparisons and a P-value < 0.05 
was regarded as the 
discrimination point for 
significance. 

Results 

According to the exclusion criteria, 
a total of 400 patients were 
examined and only 358 included in 
the study. Among them, 38.5% 
were young adults (aged less than 
45 years), 45% were males, 77.9% 
had maxillary involvement, 65.4% 
had mandibular involvement, and 
43.3% had both arches were 
involved. 

Totally dentate maxillary arches 
were found in 22.1% of cases, 
while 14%, 22.6%, 38%, and 3.4% 
of cases were class I, class II, class 
III and class IV partially 
edentulous, respectively. 
Regarding the mandibular arch, 
34.6% of  cases were totally 
dentate, while 25.1%, 22.6%, 
15.1%, and 2.5 % of cases were 
class I, class II, class III and class IV 
partially edentulous, respectively. 

 

 

 



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 N   % 

Age <45 year 138 38.5% 

≥45 year 220 61.5% 

Sex  Male 161 45% 

Female 197 55% 

Maxilla Dentate 79 22.1% 

Class I 50 14% 

Class II 81 22.6% 

Class III 136 38% 

Class IV 12 3.4% 

Mandible Dentate 124 34.6% 

Class I 90 25.1% 

Class II 81 22.6% 

Class III 54 15.1% 

Class IV 9 2.5% 

Jaw Maxilla 279 77.9% 

Mandible 234 65.4% 

Both 155 43.3% 

At least class Class I 50 14% 

Class II 112 31.3% 

Class III 175 48.9% 

Class IV 21 5.9% 

Table 2 displays the frequency of 
Kennedy's classes in the maxillary 
and mandibular arches. Frequency 
of class I pattern in the mandible 
was significantly higher than that 
on the maxillary arch (25.1% vs 

14%, P=0.001), while the rate of 
class III pattern in the maxillary 
arch was significantly higher than 
that of the mandibular arch (38% 
vs 15.1%, P=0.001). No differences 
were found between class II and IV 

patterns and affected arches 
(p>0.05). 

 

Table 1. Distribution of studied cases according to the studied characteristics. 



The Prevalence of Par.al Edentulism and Associated Factors: A Cross-Sec.onal Study   
 

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 Mandible  Maxilla  P-value 

 N  % N  %  

Class I 90 25.1% 50 14% 0.001 

Class II 81 22.6% 81 22.6% 1 

Class III 54 15.1% 136 38% 0.001 

Class IV 9 2.5% 12 3.4% 0.506 

 

Class III was more prevalent 
among younger people (51.4%), 
which is significantly higher than 
the frequency found at the old age 
group (48.6%) (Table 3). Classes I 
and II had the highest incidence 
among older people (78% and 

77.7%, respectively), and both 
were significantly higher than the 
frequency found in younger 
people (22% and 22.3%, 
respectively). It was found that 
bounded saddles changed into 
free end saddles as people aged. 

Class IV was the least frequent 
pattern, but more cases were 
found among younger people 
(57.1%) in comparison to the old 
age group (42.9%). 

 

 <45 year =>45 year P-value 

N % N % 

Class Class I 11 22% 39 78% 0.01 

Class II 25 22.3% 87 77.7% 0.001 

Class III 90 51.4% 85 48.6% 0.001 

Class IV 12 57.1% 9 42.9% 0.071 

 

Frequency of various Kennedy 
classes according to gender is 
shown in Table 4. No significant 

differences were noticed between 
class I, II or III by gender (P>0.05), 
but the rate of class IV among 

males (76.2%) was significantly 
higher than that of females 
(23.8%) (P=0.033). 

 

 

 

 

Table 2. Frequency of various Kennedy's classes in the maxillary and mandibular arches. 

Table 3. Frequency of Kennedy’s classes according to age. 



The Prevalence of Par.al Edentulism and Associated Factors: A Cross-Sec.onal Study   
 

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 Male Female P-value  

N   % N  % 

 class Class I 23 46% 27 54% 0.875 

Class II 43 38.4% 69 61.6% 0.091 

Class III 79 45.1% 96 54.9% 0.949 

Class IV 16 76.2% 5 23.8% 0.033 

Discussion  

Removable partial dentures (RPDs) 
should be classified in order to 
facilitate identification and 
enhance training. Kennedy's 
classification was employed in this 
study because it provides a simple 
method to visualize the partially 
edentulous arch, enables a logical 
approach to design problems, and 
is therefore a logical method of 
classification [18,20]. 

In the present study, the high 
percentage of class III partial 
edentulism was in accordance 
with various studies that found 
Kennedy class III is the most 
prevalent pattern of partial 
edentulism [15,21-25]. The result 
can be explained by the higher 
involvement of the maxillary arch, 
which recorded higher frequency 
of class III partial edentulism 
compared with the mandibular 
arch, due to the relative early loss 
of premolars and molars [26-28]. 

The low prevalence of Kennedy 
class IV can be attributed to the 
lower chance of tooth loss in the 
anterior region compared to the 
molar region. Fixed restorations 
are preferred for the treatment of 
such edentulism. Patients 
probably give more care and 
attention to anterior teeth 
[15,29,30]. 

In this study, class III partial 
edentulism and maxillary arch 
were significantly correlated. 
Previous work [18,22,31] found 
that Kennedy's class III was 
common in the maxillary arch. This 
study showed no association 
between class II and maxillary 
arch, and this is in disagreement 
with previous reported data [32], 
which showed a higher incidence 
of class II in the maxillary arch, and 
this may reflect differences in 
personal habits of oral hygiene. In 
this study, there was a significant 
correlation between Kennedy's 

class I and mandibular arch. This 
result is in line with previous 
studies [29,33], in which the 
mandible was the arch with the 
highest prevalence of Kennedy's 
class I occurrence.  Kennedy class I 
seems to be more commonly 
treated by RPDs [22,24]. The early 
eruption of mandibular teeth in 
the oral cavity, which predisposes 
them to greater caries rates and 
increased chances of tooth 
extraction, may be the cause of 
the higher incidence of class I in 
the mandibular arch [18]. 

The study found that young group 
had more class III partial 
edentulism. Older age groups had 
more distal extension (class I, 
followed by class II). Higher rates 
of class III in younger age groups 
may be attributed to early first 
molar loss caused by caries. Age-
related tooth loss causes the 
preexisting saddle to be extended, 
which results in classes I and II 

Table 4. Frequency of Kennedy classes according to gender. 



The Prevalence of Par.al Edentulism and Associated Factors: A Cross-Sec.onal Study   
 

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[16]. These results were in 
accordance with previous data 
from Saudi Arabia [23,24], which 
showed higher occurrence of free 
extended spaces among older 
people. These studies reported a 
higher frequency of class III and 
class I partial edentulism among 
younger and older people, 
respectively.  

Several studies showed a high 
tendency for class I and class II 
increases with age 
[15,16,18,25,34]. 

 The data showed no evidence of a 
significant relationship between 
Kennedy classes and gender. 
Regarding class IV, it was more 
common among males and this 
may be due to maxillary central 
incisors trauma caused by physical 
injuries, such as car and bike 
accidents, or due to male violent 
behavior compared with females. 

Conclusion 

Kennedy's class III is the most 
common pattern in the maxillary 
arch, whereas Kennedy's class I is 
more common in the mandibular 
arch. Age had a significant 
influence on different frequencies 
of Kennedy classes, while gender 
had a significant effect on the 
prevalence of Kennedy class IV 
only. It was clear that as people 
aged, their saddles would change 
from being bounded to being free. 

Conflicts of interest 

The authors declare that they 
have no conflicts of interest. 

Funding  

This research received no specific 
grant from any funding agency in 
the public, commercial, or not-for-
profit sectors. 

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