Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia – A Retrospective Study of 3 Years

Abstract

Aim: To report the prevalence of impacted third molars according to the age, gender and type among Saudi population.

Materials and methods: This retrospective study involved 3800 panoramic radiographs of subjects aged 18 to 45 years who presented to the College of Dentistry, King Khalid University, Abha, Kingdom of Saudi Arabia for oral care during the period from February 2009 to February 2011. Data collected was entered into a spreadsheet (Excel 2000; Microsoft, US) and analyzed using Statistical Package for Social Sciences (SPSS) version 16.0. Results: A total of 713 impacted teeth were identified (18.76%) (p=0.003). The male to female ratio with impacted third molars was 604:109 (5.54:1) and the ratio of patients with impacted teeth was (5:1). Age group 1 (i.e., 20 to 25 years)had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age. Conclusion: Incidence of tooth impaction is higher in the mandible than in maxilla. Males had a higher incidence of third molar impaction as compared to the females. Highest incidence is found in the age group of 20-25 years. Mesio-angular impaction was the most predominant type.

How to cite this article: Syed KB, Kota Z, Ibrahim M, Bagi MA, Assiri MA. "Prevalence of Impacted Molar Teeth among Saudi Population in Asir Region, Saudi Arabia – A Retrospective Study of 3 Years". J Int Oral Health 2013; 5(1):43-47.

Introduction:

Tooth impaction is a frequent phenomenon1,2. An impacted tooth is one that is erupted, partially erupted, or unerupted and will not eventually assume a normal arch relationship with the other teeth and tissues3. Local factors causing third molar impaction include crowding, ectopic position of the tooth germ, supernumerary teeth, and soft tissue or bony lesions. Mandibular and maxillary third molars are the most frequently impacted teeth, with slight predilection to the impacted teeth, with slight predilection to the former3,4. The third molars being the last to erupt have a relatively high chance of becoming impacted5. Many theories have been proposed to explain the incidence of impacted mandibular third molars. The prominent among these are mendelian theory, phylogenic theory and orthodontic theory. Most of these theories stress on the discrepancy of jaw size to the tooth size which further has been related to the dietary habits which varies from one region to the other. Considerable variation has been reported in the prevalence and distribution of impacted teeth in different regions of the jaw. Factors affecting the prevalence include the age, timing of dental eruption, and the radiographic criteria for dental development and eruption1. Data regarding the Khalid University, Abha, Kingdom of Saudi Arabia, for oral care during the period from February 2009 to February 2011. All panoramic radiographs were taken with standardized equipment and specifications. The tooth was considered impacted when it was not aligned with the rest of the teeth in occlusion. Data regarding age, sex, number of impacted teeth, prevalence of impacted third molars and the role of various factors influencing the morbidity associated with these teeth among Saudi population is scarce. The purpose of this study was to report the prevalence of impacted third molars according to the age, gender and type of impactionamong Saudi population.

Materials and Methods:

This retrospective study involved 3800 panoramic radiographs of subjects aged 18 to 45 years who had presented to the College of Dentistry, King arch involved, and type of impaction were obtained from patients' records and panoramic radiographs were individually examined by a two investigators.

The angulation of impacted third molar was recorded based on WINTER' s classification with reference to the angle formed between the intersected longitudinal axes of second molar and third molars. The angulation of impaction was measured using Queket al.,(2003) method to classify vertical impaction (10° to -10°), mesioangular impaction (11° to 79°), horizontal impaction (80° to 100°), distoangular impaction (-11° to -79°).

Data collected was entered into a spreadsheet (Excel 2000; Microsoft, US) and analyzed subsequently using Statistical Package for Social Sciences (SPSS) version 16.0. The prevalence of impacted third molars in relation to age, gender and type was assessed and displayed by frequency and percentage.p value assessed through Pearson Chi-square test.

Results:

The study sample comprised of 3800 panoramic radiographs. A total of 713 impacted teeth were mandibular arches (32.3%). In 18.4%, the maxillary arch alonehad impacted third molars(Table I). The ratio of mandibular to maxillary third molar impaction was 2.68:1.

Table I: Impaction Occurrence in Relation to Age Group.

Age Group	Impaction Occurence			Total
	Maxillary	Mandibular	Arches
1 (20-25 years)	75	212	173	460
	16.3%	46.1%	37.6%	100.0%
2 (26-30 years)	34	94	39	167
	20.4%	56.3%	23.4%	100.0%
3 (31-35 years)	18	41	14	73
	24.7%	56.2%	19.2%	100.0%
4 (36-40 years)	4	5	4	13
	30.8%	38.5%	30.8%	100.0%
Total	131	352	230	713
	18.4%	49.4%	32.3%	100.0%

In both males and females, the impacted third molars were more prevalent in mandibular arch (49.5% and 48.62%) (Table III). The male to female ratio with impacted third molars was 604:109 (5.54:1) with a p value of 0.707(p=0.707) (Table IV) which is not significant statistically.

Table III: Impaction Occurrence in Relation to Gender.

Gender	Impaction Occurence			Total
	Maxillary	Mandibular	Both the Arches
Male	108	299	197	604
	17.9%	49.5%	32.6%	100.0%
Female	23	53	33	109
	21.1%	48.6%	30.3%	100.0%
Total	131	352	230	713
	18.4%	49.4%	32.3%	100.0%

Table IV: p Value for Impaction Occurrence in Relation to Gender.

	Value	df	Asymp. (2-sided) (p value)
Pearson Chi-Square	0.692(a)	2	0.707

Among the impacted mandibular third molars, 50.75% of the patients had mesio-angular impaction which constitutes the majority and only 1.4% of the patients had disto-angular impaction. identified (18.76%)(p=0.003) (Table II). The male to female ratio with impacted third molars was 604:109 (5.54:1) and the ratio of patients with impacted teeth was (5:1). Age group 1 (i.e., 20 to 25 years)(Table I) had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age.

Table II: p Value for Impaction Occurrence in Relation to Age Group.

	Value	df	Asymp. (2-sided) (p value)
Pearson Chi-Square	19.774(a)	6	0.003

Of the 713 impacted molars, majority were mandibular third molars (49.4%), followed by 52% of the impacted maxillary third molars had vertical impaction and the least prevalent among the impacted maxillary molars was horizontal impaction (1.5%).

Discussion:

An impacted tooth is "a tooth that cannot, or will not erupt into its normal functioning position, and is therefore pathologic and requires treatment"4. impacted teeth in both the maxillary and Any permanent tooth in the dental arch can be impacted, but the teeth most frequently involved in a descending order are the mandibular and maxillary third molar, the maxillary canines, the mandibular and maxillary second premolar, and maxillary central incisors6. According to Othman R et al., the mandibular third molars are the most frequently impacted teeth in the humans and surgical extraction has become one of the most common dentoalveolar surgeries7. The etiology of impaction is multifactorial8. Impacted teeth may be associated with periodontal disease, dental caries, odontogenic cyst and tumors, pain of unexplained origin, jaw fracture, and resorption of root of the adjacent tooth9.

This retrospective study to assess the prevalence of impacted third molars among Saudi population included 3800 subjects. To ensure diagnostic validity in this study, radiographic findings were verified with clinical records, which were collected on standard forms as part of routine examination process. A total of 713 (18.76%) patients had impacted third molars with a p value of 0.003(p=0.003) (Table II) which is statistically significant. Haider and Shalhoub10in 1986 conducted a similar study among Saudi population and reported 34% and 29% prevalence of impacted third molars for males and females respectively. Ioannis G et al2.,in their retrospective study among Greek population reviewed 425 patients with impacted teeth and reported a prevalence rate of 0.001(p=0.001). FCS Chu et al1., conducted a retrospective study among Hong Kong Chinese population which included 7486 patients and reported 28.3% prevalence of impacted third molars. Alexander T11et al., reported a similar prevalence rate of 27.8% among Hong Kong population.

The male to female ratio with impacted third molars was 604:109 (5.54:1) with a p value of 0.707(p=0.707) (Table IV)which is not significant statistically. The results in this study for the male to female ratio of impacted molars is quite similar to the study conducted by Ioannis G et al2., (p=0.651).Mwaniki D et al5.,in their study involving Kenya patients reported the male to female ratio as 7:5.

Age group 1 (20 – 25 years)had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age. Similar to other studies and as widely stated in the literature2,4,12, the prevalence of impacted third molars was much higher in the mandibular arch as compared to maxillary arch (49.4% to 18.4%). In both males and females, the impacted third molars were more prevalent in mandibular arch (49.5% and 48.62%). Even with regard to the age group, the maximum prevalence of impacted third molars was in the mandibular arch in any of the age group in this study. The ratio of mandibular to maxillary third molar impaction was 2.68:1.

Age group 1 (20 – 25 years)had the highest prevalence of third molar tooth impaction (64.5%) and this decreased with increasing age. Similar to other studies and as widely stated in the literature2,4,12, the prevalence of impacted third molars was much higher in the mandibular arch as compared to maxillary arch (49.4% to 18.4%). In both males and females, the impacted third molars were more prevalent in mandibular arch (49.5% and 48.62%). Even with regard to the age group, the maximum prevalence of impacted third molars was in the mandibular arch in any of the age group in this study. The ratio of mandibular to maxillary third molar impaction was 2.68:1.

Conclusion:

1. Incidence of tooth impaction is higher in the mandible than in maxilla.

2. Males had a higher incidence of third molar impaction as compared to the females.

3. Highest incidence is found in the age group of 20-25 years.

4. Mesio-angular impaction was the most predominant type.

Acknowledgement :

The authors thank Dr Abdullah A Refeidi, Honourable Dean, College of Dentistry, King Khalid University, Abha, Kingdom of Saudi Arabia for his active encouragement and support.