Patterns of Mandibular Third Molar Impaction in an Iranian Subpopulation

This retrospective descriptive study evaluated 1000 panoramic radiographs retrieved from the archives of a private radiology clinic in Kermanshah city, Iran. Depth of impaction, position of impacted mandibular third molar relative to the mandibular ramus according to Pell and Gregory’s classification and angle of impacted tooth according to Winter’s classification were determined. Data were analyzed using the Chi-square and Wilcoxon tests.

Results:

Of 1000 radiographs, 230 (23%) showed an impaction of at least one mandibular third molar. Mandibular third molar impaction was more common in females (60%). Mesioangular (35.9%) and vertical (34.8%) impactions were the most common angles of impaction in the right and left sides, respectively. Level C (40.3%) and Class I (63.7%) were the most common types of impaction in terms of depth of impaction and position relative to ramus, respectively. No significant difference was observed between the right and left sides of the mandible in terms of patterns of mandibular third molar impaction (p>0.05).

Conclusion:

Mandibular third molar impaction was relatively common in the studied population. The mesioangular, level C and Class I impaction patterns were the most frequent.

Keywords:
Surgery, Oral; Dentition, Permanent; Molar, Third; Tooth, Impacted

	Side
Variables	Right	Left	Bilateral	p-value
	N (%)	N (%)	N (%)
Gender
Male	27 (29.3)	16 (17.4)	49 (53.3)	0.864
Female	45 (32.6)	22 (15.9)	71 (51.4)
Age Group
18-30 Years	29 (28.2)	15 (14.6)	59 (57.3)	0.044
31-40 Years	27 (31.0)	14 (16.1)	46 (52.9)
41-50 Years	13 (43.3)	4 (13.3)	13 (43.3)
50-58 Years	3 (30.0)	5 (50.0)	2 (20.0)

	Impaction Deep
Side	Level A	Level B	Level C	Total	p-value
	N (%)	N (%)	N (%)	N (%)
Right	55 (28.6)	60 (31.3)	77 (40.1)	192 (100.0)	0.651
Left	36 (22.8)	58 (36.7)	64 (40.5)	158 (100.0)

	Position
Side	Class I	Class II	Class III	Total	p-value
	N (%)	N (%)	N (%)	N (%)
Right	116 (60.4)	56 (29.2)	20 (10.4)	192 (100.0)	0.683
Left	107 (67.7)	36 (22.8)	15 (9.5)	158 (100.0)

	Angle of Impaction
Side	Vertical	Mesioangular	Horizontal	Distoangular	Buccolingual	Other	Total	p-value
	N (%)	N (%)	N (%)	N (%)	N (%)	N (%)	N (%)
Right	63 (32.8)	69 (35.9)	46 (24)	3 (1.6)	10 (5.2)	1 (0.5)	192 (100.0)	0.581
Left	55 (34.8)	52 (32.9)	41 (25.9)	3 (1.9)	7 (4.4)	0 (0.0)	158 (100.0)

		Impaction Deep
Side	Gender	Level A	Level B	Level C	Total	p-value
		N (%)	N (%)	N (%)	N (%)
Right	Male	16 (21.1)	28 (36.8)	32 (42.1)	76 (100.0)	0.141
	Female	39 (33.6)	32 (27.6)	45 (38.8)	116 (100.0)
Left	Male	12 (18.5)	23 (35.4)	30 (46.2)	65 (100.0)	0.401
	Female	24 (25.8)	35 (37.6)	34 (36.6)	93 (100.0)

		Position
Side	Gender	Class I	Class II	Class III	Total	p-value
		N (%)	N (%)	N (%)	N (%)
Right	Male	51 (67.1)	18 (23.7)	7 (9.2)	76 (100.0)	0.301
	Female	65 (56.0)	38 (32.8)	13 (11.2)	116 (100.0)
Left	Male	54 (83.1)	7 (10.8)	4 (6.2)	65 (100.0)	0.002
	Female	53 (57.0)	29 (31.2)	11 (11.8)	93 (100.0)

		Angle of Impaction
Side	Gender	Vertical	Mesioangular	Horizontal	Distoangular	Buccolingual	Others	p-value
		N (%)	N (%)	N (%)	N (%)	N (%)	N (%)
Right	Males	23(30.3)	30 (39.5)	19 (25.0)	0 (0.0)	4 (5.3)	0 (0.0)	0.644
	Females	40 (34.5)	39 (33.6)	27 (23.3)	3 (2.6)	6 (5.2)	1 (0.9)
Left	Males	19 (29.2)	23 (35.4)	21 (32.3)	1 (1.5)	1 (1.5)	0 (0.0)	0.280
	Females	36 (38.7)	29 (31.2)	20 (21.5)	2 (2.2)	6 (6.5)	0 (0.0)

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[1] Author to whom correspondence should be addressed: Atefeh Khavid, Assistant Professor, Department of Oral and Maxillofacial Radiology, Kermanshah University of Medical Sciences, Kermanshah, Iran. Phone: +9891 88362065. E-mail: atefehkhavid@gmail.com.