Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e4
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Journal of Cranio-Maxillo-Facial Surgery journal homepage: www.jcmfs.com
Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study Rajasekhar Gaddipati*, Sudhir Ramisetty 1, Nandagopal Vura 2, Rajeev Reddy Kanduri 2, Vinay Kumar Gunda 3 Department of Oral and Maxillofacial Surgery (Head: Prof. Rajasekhar Gaddipati), Mamata Dental College & Hospital, Giriprasad Nagar, Khammam, Andhra Pradesh 507002, India
a r t i c l e i n f o
a b s t r a c t
Article history: Paper received 19 September 2013 Accepted 6 January 2014
Background: Previous retrospective analyses prove that impacted mandibular third molars (M3s) increase the risk of angle fractures and decrease the risk of concomitant fractures to the condyle. Study design: A retrospective cohort was designed for patients reported to the Department of Oral and Maxillofacial Surgery from January 2011 till June 2013. The study variables are presence or absence of third molar, if it is present, their position, classified using the Pell and Gregory system; angulation, classified using Shiller’s method. The outcome variables were angle and condyle fractures. Materials and methods: Hospital records and panoramic radiographs were used to determine and classify these variables. The study sample comprised of 118 mandibular angle and condyle fractures in 110 patients. Database was constructed and analysed using SPSS version 10.0. Conclusion: This present retrospective study concluded that the presence of impacted third molar predisposes the angle to fracture and reduces the risk of a concomitant condylar fracture. However absence of impacted third molar increases the risk of condylar fracture. The highest incidence of angle fracture was observed in position A impacted mandibular third molars. And there is no significant relationship, concerning ramus position and angulation of impacted mandibular third molars with the angle fracture. Ó 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Keywords: Angle Condyle Impacted third molar Mandible
1. Introduction The most common isolated fracture site among the facial bones is the nasal bone, followed by mandible, orbital bone, zygoma, maxilla and frontal bone. This high incidence of mandibular fractures could be related to its prominent position and exposed situation (Rudderman and Mullen, 1992; Banks and Brown, 2005; Hwang and You, 2010; Thangavelu and Yoganandha, 2010). The fractures of the mandible are usually influenced by factors such as direction, severity and impact of force, presence of soft tissue bulk, occlusal loading pattern and biomechanical characteristics such as
* Corresponding author. Tel.: þ91 9000018128. E-mail addresses: [email protected] (R. Gaddipati), drsudhir_007@ hotmail.com (S. Ramisetty), [email protected], [email protected] (N. Vura), [email protected] (R.R. Kanduri), vinay_gunda777@yahoo. co.in (V.K. Gunda). 1 Tel.: þ91 9963117979. 2 Tel.: þ91 9908296688. 3 Tel.: þ91 9963054606.
bone density, mass and anatomic structures creating weak areas (Lee and Dodson, 2000; Meisami et al., 2002). Mandibular condylar fractures are more frequent accounting for 29e52% of all mandibular fractures (Zhou et al., 2013). Reitzik hypothesized that, as sharp angulation concentrates stress, the angle of the mandible becomes a weak area and certain injuries deform the mandible beyond its yield point (Reitzik, 1995). The weakest area of the dentate mandible is the condyle and forces inflicted remain well absorbed at the angle, the mandible fractures at the angle sparing the condyle. Third molars are the last to erupt in the permanent teeth series. These teeth are the most likely to be impacted (Peterson, 2003). They occupy different positions and angulations in relation to the anterior border of ramus and occlusal level of the second molar. Studies have shown that fractures occurred at significantly lower forces when the mandibular third molar teeth were buried within the bone (Huelke et al., 1962). Tevepaugh and Dodson showed that patients with mandibular third molars were 2.8 times more likely to have an angle fracture than those without third molars, irrespective of eruption status (Tevepaugh and Dodson, 1995). Safdar
1010-5182/$ e see front matter Ó 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jcms.2014.01.038
Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
2
R. Gaddipati et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e4
and Meechan also asserted the association between the position of third molars and the risk of mandibular angle fractures (Safdar and Meechan, 1995). Recent clinical studies showed that the risk of angle fracture is greater for superficially placed third molars, and decreased for deeper impactions (Reitzik et al., 1978; Safdar and Meechan, 1995). Based on the current biomechanical model, it has been hypothesized that the third molar weakens the angle by decreasing the bone mass in the region making the mandibular angle more susceptible to fracture (Lee and Dodson, 2000). The objective of this study was to systematically analyse the relationship between the status and position of third molars, angle and condyle fractures in a group of patients treated for mandibular fractures.
2. Materials and methods 2.1. Study design and sample Retrospective study based on patients records and radiographs (Orthopantomograms). 110 individuals of age group 18 yearse55 years, with mandibular fracture at angle and condyle who reported to the Department of Oral and Maxillofacial Surgery, Mamata Dental College & Hospital (Khammam, A.P., India), between January 2011 and June 2013 were included in the study.
2.2. Study variables Hospital records and panoramic radiographs were used to assess the presence, position and angulation of impacted third molars (predictor variables) and the incidence of mandibular angle and condyle fractures (outcome variables). Winter’s classification was used to classify third molars into mesioangular, distoangular, vertical and horizontal (Winter, 1926). The classification of Sciller (Sciller, 1975) was used to classify angulations of third molars as vertical, 10 , mesioangular and distoangular, 11 e70 and horizontal, more than 71. The relationship of third molar to the ramus of the mandible was grouped according to the classification of Pell and Gregory (Sciller, 1975). At level 1, sufficient space is present between the ramus of the mandible and the second molar to accommodate the crown of the third molar. At level 2, space is insufficient. At level 3, the third molar is located all or mostly within the vertical ramus. The relative depth of third molar was grouped according to the classification of Archer (Archer, 1975). At position A, the highest point of the third molar is on the same level as, or below the occlusal plane of the adjacent second molar. At position B, the highest point of third molar is below the occlusal plane but above the cervical line of the second molar. At position C, the highest point of third molar is below the cervical line of the second molar.
2.3. Variable outcomes Mandibular angle fracture was determined using the definition given by Kelly and Harrigan: A fracture located posterior to the second molar extending from any point on the curve formed by the junction of the body and ramus in the retromolar area to any point on the curve formed by the inferior border of the body and posterior border of the ramus of the mandible (Kelly and Harrigan, 1975). The condyle fracture was defined as a fracture with the fracture line superior to the sigmoid notch.
2.4. Data management and analysis The database was constructed and analysis performed using SPSS version 10.0. Data were analysed by calculating the means and standard deviation, and cohort comparisons were made using the x2 test. p values less than 0.005 were considered statistically significant. 3. Results Cohort group consists of 110 patients with 125 mandibular angle and condyle fractures caused by road traffic accident (98; 89%), assault (7; 6.3%), fall (5; 4.5%) as mentioned in Table 1. The only method for assessing severity of trauma force was on the basis of the number of fracture sites. A bilateral fracture pattern was seen in 84 patients (76.3%), a unilateral fracture pattern was seen in 26 patients (23.6%). Mandibular angle fractures were 72, isolated fractures were 21 (26.1%) and associated fractures were 51 (73.9%). Mandibular condyle fractures were 53, isolated fractures were 3 (5.6%) and associated fractures were 50 (94.4%). The cohort of 110 patients with 125 fractures of the mandible had third molar absent in 7, with the remaining 118 fractures of the mandible having a third molar. As shown in Table 2, out of 118 fractures of the mandible associated with a third molar, an impacted third molar was found in 66 fractures and an erupted third molar was found in 52 fractures. In this study, the incidence of mandibular fracture was high when associated with third molars, the unerupted third molar present group had a higher proportion of angle fracture (58 fractures, 87.8%) than those in unerupted third molar absent group (8 fractures, 12.2%). Condyle fractures were more common in third molar absent group (43 fractures, 82.6%) than those in third molar present group (9 fractures, 17.4%). Table 3 shows, details of ramus position, occlusal position, angulation of third molars were determined. Tables 4 and 6 shows that there was no significant relationship with the angle fractures taking into consideration the ramus position and angulation of impacted third molars (see Table 4). Table 7 shows that condyle fractures are more commonly associated with other mandibular fractures. Table 5 shows that the highest incidence of angle fracture was observed in position A followed by position B (see Table 8). 4. Discussion The most common cause of mandibular fracture is traffic related followed by the violence (Chrcanovik et al., 2012). Accordingly in the present study road traffic accident is the main cause for mandibular fractures followed by an assault/violence. The external oblique ridge provides strength for the mandible in that region of the jaw, when a tooth is completely in occlusion, the widest portion of the tooth is in the mouth and the external oblique ridge remains unaltered there by strengthening the mandible in that area. When the tooth is completely impacted, the widest portion of the tooth is generally found below the external oblique ridge. When the tooth is
Table 1 Etiology of angle and condyle fracture. Cause of injury
Angle and condyle fractures n ¼ 110
Road traffic accident Assault Fall
98 (89%) 7 (6.3%) 5 (4.5%)
Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
R. Gaddipati et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e4 Table 2 Relationship between impacted third molars and the risk of angle and condyle fractures. Number of fractures associated with impacted third molar n ¼ 118
Condyle fracturea
Angle fractureb
Absent
Present
Absent
Present
Absent (52) Present (66)
11 (21.2%) 60 (90.9%)
41 (78.8%) 6 (9.1%)
41 (78.8%) 6 (9.1%)
11 (21.2%) 60 (90.9%)
a b
Odds ratio: 0.027; 95% CI: 0.009e0.078; p < 0.001. Odds ratio: 37.273; 95% CI: 12.771e108.78; p < 0.001.
Table 3 Variables further quantified n ¼ 66. Relationship with ramus
Occlusal position
Angulation
Class I e 10 (15.1%) Class II e 35 (53%) Class III e 21 (31%)
Position A e 25 (37.8%) Position B e 22 (33.3%) Position C e 19 (28.7%)
Mesioangular e 39 (59%) Distoangular e 12 (18.1%) Vertical e 8 (12.1%) Horizontal e 7 (10.6%)
Table 4 Relationship between the third molar position and risk of angle fracture. Ramus position
Angle fractures n ¼ 58 Present (n ¼ 58)
Absent (n ¼ 8)
Class I Class II Class III Total
10 30 18 58
e 5 (14.3%) 3 (14.3%) 8 (12.1%)
(100%) (85.7%) (85.7%) (87.9%)
x2 ¼ 1.626; df ¼ 2; p ¼ 0.444; not significant.
Table 5 Relationship between the third molar position and risk of angle fracture. Occlusal position
Angle fractures n ¼ 58 Present (n ¼ 58)
Absent (n ¼ 8)
Position A Position B Position C Total
25 22 11 58
e e 8 (42.1%) 8 (12.1%)
(100%) (100%) (57.9%) (87.9%)
x2 ¼ 22.519; df ¼ 2; p < 0.001; highly significant.
Table 6 Relationship between the third molar angulation and risk of angle fracture. Angulation
Mesioangular Distoangular Vertical Horizontal Total
Angle fractures n ¼ 58 Present (n ¼ 58)
Absent (n ¼ 8)
34 12 6 6 58
5 (12.8%) e 2 (25%) 1 (14.3%) 8 (12.1%)
(87.2%) (100%) (75%) (85.7%) (87.9%)
x2 ¼ 2.950; df ¼ 3; p ¼ 0.399; not significant.
Table 7 Sex predilection for angle and condyle fractures n ¼ 110.
Table 8 Incidence of isolated and associated angle and condyle fractures. Fracture
Isolated
Associated
Angle fracture Condyle fracture
25 (43.1%) 4 (10%)
33 (56.9%) 36 (90%)
x2 ¼ 12.451; df ¼ 1; p < 0.001; highly significant.
partially impacted, it can be imagined that the tension line will be disrupted, weakening the mandibular angle and making it more susceptible to fracture (Meisami et al., 2002). Consistent with other studies, the result of this study confirmed an increased risk of angle fractures when impacted third molars were present (Safdar and Meechan, 1995; Tevepaugh and Dodson, 1995; Lee and Dodson, 2000). In addition the present study showed that increased incidence of angle fracture is present when associated with impacted third molars in position A. Thangavelu and Yoganandha conducted a retrospective study and hypothesized that higher proportion of angle fracture was present in those with unerupted mandibular third molars. Condyle fracture was more common in those with erupted third molars. The highest incidence of angle fracture was observed in Class II ramus position, position B and mesioangular impacted third molars (Thangavelu and Yoganandha, 2010). Consistent with the above study, we observed increased risk of angle fractures when impacted third molars were present and increased risk of condyle fractures when impacted third molars were absent. In contrary, we found no significant relationship between ramus position and angulation of the impacted mandibular third molar to the incidence of angle fracture, but their incidence was high when specifically associated with impacted third molars in position A followed by position B. Some authors have postulated that the presence of impacted third molars (either partial or complete) reduces the incidence of condyle fractures (Zhu et al., 2005; Duan and Zhang, 2008). This study revealed that the highest incidence of condyle fracture was noticed typically in the absence of impacted third molars (either partial or complete). The present study demonstrated that in patients who had multiple fractures, when the unerupted third molars were present (either third molars were partially erupted or completely unerupted), the patient’s injuries were often associated with both parasymphysis and angle fractures. When the unerupted third molars were absent (either third molars were absent or completely erupted), the patient’s injuries were more associated with both symphysis and condyle fractures. This suggests that when the unerupted third molars were absent (either third molars were absent or completely erupted) much of the force may be transmitted to the condylar region; hence, the increased incidence of associated fractures of the condylar process. Kober et al. (Kober et al., 2001) proposed a biomechanical model that is in agreement with the findings of this study. They suggested that if the angle was weakened by incompletely erupted third molars, the possibility of condylar fractures would be decreased, as impact forces would be dissipated by the angle fractures. If the angle was intact, with no impacted third molars, it would be resistant to fracture and more impact forces would transmit to the condyle and result in fracture. 5. Conclusion
Fracture
Male
Female
Angle fracture Condyle fracture
62 (88.6%) 33 (82.5%)
8 (11.4%) 7 (17.5%)
x2 ¼ 0.797; df ¼ 1; p ¼ 0.372; not significant.
3
Various studies state that it might not be appropriate to strengthen the mandibular angle region and make the mandible vulnerable to condylar fractures by removing the unerupted third molars.
Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
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R. Gaddipati et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e4
From this retrospective cohort, it can be concluded that the presence of an impacted third molar predisposes the angle to fracture and reduces the risk of concomitant condylar fracture. The highest incidence of angle fracture was observed in position A impacted mandibular third molars. There is no significant relationship concerning ramus position and angulation of impacted mandibular third molars with angle fractures. Sources of support None. Conflicts of interest None declared. References Archer W: Oral and maxillofacial surgery. Philadelphia: Saunders 1(5): 259e260, 311, 1975 Banks P, Brown A: Fractures of facial skeleton. St. Louis, MO: Butterworth-Heinemann, 2005 Chrcanovik BR, Abreu MHNG, Freire-Maia B, Souza LN: 1,454 mandibular fractures: a 3 year study in a hospital in Belo Horizonte, Brazil. J Craniomaxillofac Surg 40: 116e123, 2012 Duan DH, Zhang Y: Does the presence of mandibular third molars increase the risk of angle fracture and simultaneously decrease the risk of condylar fracture? Int J Oral Maxillofac Surg 37: 25e28, 2008 Huelke DF, Burdi AR, Eyman CE: Association between mandibular fractures and site of trauma, dentition and age. J Oral Surg 20: 478e481, 1962 Hwang K, You SH: Analysis of facial bone fractures: an 11 year study of 2,094 patients. Indian J Plast Surg 43: 42e48, 2010
Kelly D, Harrigan W: A survey of facial fractures related to teeth and edentulous regions. J Oral Surg 33: 146e149, 1975 Kober C, Sader R, Thiele H, Bauer HJ, Zeilhofer HF, Hoffmann KH, et al: Stress analysis of the human mandible in standard trauma situations with numerical simulation. Mund Kiefer Gesichtschir 5: 114e119, 2001 Lee JT, Dodson TB: The effect of mandibular third molar presence and position on the risk of an angle fracture. J Oral Maxillofac Surg 58: 394e398, 2000 Meisami T, Sojat A, Sandor GKB, Lawrence HP, Clokie CML: Impacted third molars and risk of angle fracture. Int J Oral Maxillofac Surg 31: 140e144, 2002 Peterson LJ: Principles of management of impacted teeth. In: Contemporary of oral and maxillofacial surgery, 4th edn. Mosby Inc., 184e212, 2003 Rudderman RH, Mullen RL: Biomechanics of the facial skeleton. Clin Plast Surg 19: 11e29, 1992 Reitzik M, Lownie F, Cleaton-jones P, Austin J: Experimental fractures of monkey mandibles. Int J Oral Surg 7: 100e103, 1978 Reitzik M: Are mandibular third molars are a risk factors for angle fractures? A retrospective cohort study. J Oral Maxillofac Surg 53: 649e650, 1995 Sciller WR: Positional changes in mesioangular impacted third molars during a year. J Am Dent Assoc 99: 460e464, 1975 Safdar N, Meechan JG: Relationship between fractures of mandibular angle and the presence and state of eruption of lower third molar. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 79: 680e684, 1995 Thangavelu R, Yoganandha: Impact of impacted mandibular third molars in mandibular angle and condyle fractures. Int J Oral Maxillofac Surg 39: 136e139, 2010 Tevepaugh DB, Dodson TB: Are mandibular third molars a factor for angle fractures? A retrospective cohort study. J Oral Maxillofac Surg 53: 646e649, 1995 Winter GB: Impacted third molars. St. Louis: American Medical Book Co.241e279, 1926 Zhu SJ, Choi BH, Kim HJ, Park WS, Huh JY, Jung JH, et al: Relationship between the presence of unerupted mandibular third molars and fractures of the mandibular condyle. Int J Oral Maxillofac Surg 34: 382e385, 2005 Zhou H, Liu Q, Cheng G, Li ZB: Aetiology, pattern and treatment of mandibular condyle fractures in 549 patients: a 22 yr retrospective study. J Craniomaxillofac Surg 41: e34ee41, 2013
Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
Contents lists available at ScienceDirect
Journal of Cranio-Maxillo-Facial Surgery journal homepage: www.jcmfs.com
Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study Rajasekhar Gaddipati*, Sudhir Ramisetty 1, Nandagopal Vura 2, Rajeev Reddy Kanduri 2, Vinay Kumar Gunda 3 Department of Oral and Maxillofacial Surgery (Head: Prof. Rajasekhar Gaddipati), Mamata Dental College & Hospital, Giriprasad Nagar, Khammam, Andhra Pradesh 507002, India
a r t i c l e i n f o
a b s t r a c t
Article history: Paper received 19 September 2013 Accepted 6 January 2014
Background: Previous retrospective analyses prove that impacted mandibular third molars (M3s) increase the risk of angle fractures and decrease the risk of concomitant fractures to the condyle. Study design: A retrospective cohort was designed for patients reported to the Department of Oral and Maxillofacial Surgery from January 2011 till June 2013. The study variables are presence or absence of third molar, if it is present, their position, classified using the Pell and Gregory system; angulation, classified using Shiller’s method. The outcome variables were angle and condyle fractures. Materials and methods: Hospital records and panoramic radiographs were used to determine and classify these variables. The study sample comprised of 118 mandibular angle and condyle fractures in 110 patients. Database was constructed and analysed using SPSS version 10.0. Conclusion: This present retrospective study concluded that the presence of impacted third molar predisposes the angle to fracture and reduces the risk of a concomitant condylar fracture. However absence of impacted third molar increases the risk of condylar fracture. The highest incidence of angle fracture was observed in position A impacted mandibular third molars. And there is no significant relationship, concerning ramus position and angulation of impacted mandibular third molars with the angle fracture. Ó 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Keywords: Angle Condyle Impacted third molar Mandible
1. Introduction The most common isolated fracture site among the facial bones is the nasal bone, followed by mandible, orbital bone, zygoma, maxilla and frontal bone. This high incidence of mandibular fractures could be related to its prominent position and exposed situation (Rudderman and Mullen, 1992; Banks and Brown, 2005; Hwang and You, 2010; Thangavelu and Yoganandha, 2010). The fractures of the mandible are usually influenced by factors such as direction, severity and impact of force, presence of soft tissue bulk, occlusal loading pattern and biomechanical characteristics such as
* Corresponding author. Tel.: þ91 9000018128. E-mail addresses: [email protected] (R. Gaddipati), drsudhir_007@ hotmail.com (S. Ramisetty), [email protected], [email protected] (N. Vura), [email protected] (R.R. Kanduri), vinay_gunda777@yahoo. co.in (V.K. Gunda). 1 Tel.: þ91 9963117979. 2 Tel.: þ91 9908296688. 3 Tel.: þ91 9963054606.
bone density, mass and anatomic structures creating weak areas (Lee and Dodson, 2000; Meisami et al., 2002). Mandibular condylar fractures are more frequent accounting for 29e52% of all mandibular fractures (Zhou et al., 2013). Reitzik hypothesized that, as sharp angulation concentrates stress, the angle of the mandible becomes a weak area and certain injuries deform the mandible beyond its yield point (Reitzik, 1995). The weakest area of the dentate mandible is the condyle and forces inflicted remain well absorbed at the angle, the mandible fractures at the angle sparing the condyle. Third molars are the last to erupt in the permanent teeth series. These teeth are the most likely to be impacted (Peterson, 2003). They occupy different positions and angulations in relation to the anterior border of ramus and occlusal level of the second molar. Studies have shown that fractures occurred at significantly lower forces when the mandibular third molar teeth were buried within the bone (Huelke et al., 1962). Tevepaugh and Dodson showed that patients with mandibular third molars were 2.8 times more likely to have an angle fracture than those without third molars, irrespective of eruption status (Tevepaugh and Dodson, 1995). Safdar
1010-5182/$ e see front matter Ó 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jcms.2014.01.038
Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
2
R. Gaddipati et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e4
and Meechan also asserted the association between the position of third molars and the risk of mandibular angle fractures (Safdar and Meechan, 1995). Recent clinical studies showed that the risk of angle fracture is greater for superficially placed third molars, and decreased for deeper impactions (Reitzik et al., 1978; Safdar and Meechan, 1995). Based on the current biomechanical model, it has been hypothesized that the third molar weakens the angle by decreasing the bone mass in the region making the mandibular angle more susceptible to fracture (Lee and Dodson, 2000). The objective of this study was to systematically analyse the relationship between the status and position of third molars, angle and condyle fractures in a group of patients treated for mandibular fractures.
2. Materials and methods 2.1. Study design and sample Retrospective study based on patients records and radiographs (Orthopantomograms). 110 individuals of age group 18 yearse55 years, with mandibular fracture at angle and condyle who reported to the Department of Oral and Maxillofacial Surgery, Mamata Dental College & Hospital (Khammam, A.P., India), between January 2011 and June 2013 were included in the study.
2.2. Study variables Hospital records and panoramic radiographs were used to assess the presence, position and angulation of impacted third molars (predictor variables) and the incidence of mandibular angle and condyle fractures (outcome variables). Winter’s classification was used to classify third molars into mesioangular, distoangular, vertical and horizontal (Winter, 1926). The classification of Sciller (Sciller, 1975) was used to classify angulations of third molars as vertical, 10 , mesioangular and distoangular, 11 e70 and horizontal, more than 71. The relationship of third molar to the ramus of the mandible was grouped according to the classification of Pell and Gregory (Sciller, 1975). At level 1, sufficient space is present between the ramus of the mandible and the second molar to accommodate the crown of the third molar. At level 2, space is insufficient. At level 3, the third molar is located all or mostly within the vertical ramus. The relative depth of third molar was grouped according to the classification of Archer (Archer, 1975). At position A, the highest point of the third molar is on the same level as, or below the occlusal plane of the adjacent second molar. At position B, the highest point of third molar is below the occlusal plane but above the cervical line of the second molar. At position C, the highest point of third molar is below the cervical line of the second molar.
2.3. Variable outcomes Mandibular angle fracture was determined using the definition given by Kelly and Harrigan: A fracture located posterior to the second molar extending from any point on the curve formed by the junction of the body and ramus in the retromolar area to any point on the curve formed by the inferior border of the body and posterior border of the ramus of the mandible (Kelly and Harrigan, 1975). The condyle fracture was defined as a fracture with the fracture line superior to the sigmoid notch.
2.4. Data management and analysis The database was constructed and analysis performed using SPSS version 10.0. Data were analysed by calculating the means and standard deviation, and cohort comparisons were made using the x2 test. p values less than 0.005 were considered statistically significant. 3. Results Cohort group consists of 110 patients with 125 mandibular angle and condyle fractures caused by road traffic accident (98; 89%), assault (7; 6.3%), fall (5; 4.5%) as mentioned in Table 1. The only method for assessing severity of trauma force was on the basis of the number of fracture sites. A bilateral fracture pattern was seen in 84 patients (76.3%), a unilateral fracture pattern was seen in 26 patients (23.6%). Mandibular angle fractures were 72, isolated fractures were 21 (26.1%) and associated fractures were 51 (73.9%). Mandibular condyle fractures were 53, isolated fractures were 3 (5.6%) and associated fractures were 50 (94.4%). The cohort of 110 patients with 125 fractures of the mandible had third molar absent in 7, with the remaining 118 fractures of the mandible having a third molar. As shown in Table 2, out of 118 fractures of the mandible associated with a third molar, an impacted third molar was found in 66 fractures and an erupted third molar was found in 52 fractures. In this study, the incidence of mandibular fracture was high when associated with third molars, the unerupted third molar present group had a higher proportion of angle fracture (58 fractures, 87.8%) than those in unerupted third molar absent group (8 fractures, 12.2%). Condyle fractures were more common in third molar absent group (43 fractures, 82.6%) than those in third molar present group (9 fractures, 17.4%). Table 3 shows, details of ramus position, occlusal position, angulation of third molars were determined. Tables 4 and 6 shows that there was no significant relationship with the angle fractures taking into consideration the ramus position and angulation of impacted third molars (see Table 4). Table 7 shows that condyle fractures are more commonly associated with other mandibular fractures. Table 5 shows that the highest incidence of angle fracture was observed in position A followed by position B (see Table 8). 4. Discussion The most common cause of mandibular fracture is traffic related followed by the violence (Chrcanovik et al., 2012). Accordingly in the present study road traffic accident is the main cause for mandibular fractures followed by an assault/violence. The external oblique ridge provides strength for the mandible in that region of the jaw, when a tooth is completely in occlusion, the widest portion of the tooth is in the mouth and the external oblique ridge remains unaltered there by strengthening the mandible in that area. When the tooth is completely impacted, the widest portion of the tooth is generally found below the external oblique ridge. When the tooth is
Table 1 Etiology of angle and condyle fracture. Cause of injury
Angle and condyle fractures n ¼ 110
Road traffic accident Assault Fall
98 (89%) 7 (6.3%) 5 (4.5%)
Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
R. Gaddipati et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e4 Table 2 Relationship between impacted third molars and the risk of angle and condyle fractures. Number of fractures associated with impacted third molar n ¼ 118
Condyle fracturea
Angle fractureb
Absent
Present
Absent
Present
Absent (52) Present (66)
11 (21.2%) 60 (90.9%)
41 (78.8%) 6 (9.1%)
41 (78.8%) 6 (9.1%)
11 (21.2%) 60 (90.9%)
a b
Odds ratio: 0.027; 95% CI: 0.009e0.078; p < 0.001. Odds ratio: 37.273; 95% CI: 12.771e108.78; p < 0.001.
Table 3 Variables further quantified n ¼ 66. Relationship with ramus
Occlusal position
Angulation
Class I e 10 (15.1%) Class II e 35 (53%) Class III e 21 (31%)
Position A e 25 (37.8%) Position B e 22 (33.3%) Position C e 19 (28.7%)
Mesioangular e 39 (59%) Distoangular e 12 (18.1%) Vertical e 8 (12.1%) Horizontal e 7 (10.6%)
Table 4 Relationship between the third molar position and risk of angle fracture. Ramus position
Angle fractures n ¼ 58 Present (n ¼ 58)
Absent (n ¼ 8)
Class I Class II Class III Total
10 30 18 58
e 5 (14.3%) 3 (14.3%) 8 (12.1%)
(100%) (85.7%) (85.7%) (87.9%)
x2 ¼ 1.626; df ¼ 2; p ¼ 0.444; not significant.
Table 5 Relationship between the third molar position and risk of angle fracture. Occlusal position
Angle fractures n ¼ 58 Present (n ¼ 58)
Absent (n ¼ 8)
Position A Position B Position C Total
25 22 11 58
e e 8 (42.1%) 8 (12.1%)
(100%) (100%) (57.9%) (87.9%)
x2 ¼ 22.519; df ¼ 2; p < 0.001; highly significant.
Table 6 Relationship between the third molar angulation and risk of angle fracture. Angulation
Mesioangular Distoangular Vertical Horizontal Total
Angle fractures n ¼ 58 Present (n ¼ 58)
Absent (n ¼ 8)
34 12 6 6 58
5 (12.8%) e 2 (25%) 1 (14.3%) 8 (12.1%)
(87.2%) (100%) (75%) (85.7%) (87.9%)
x2 ¼ 2.950; df ¼ 3; p ¼ 0.399; not significant.
Table 7 Sex predilection for angle and condyle fractures n ¼ 110.
Table 8 Incidence of isolated and associated angle and condyle fractures. Fracture
Isolated
Associated
Angle fracture Condyle fracture
25 (43.1%) 4 (10%)
33 (56.9%) 36 (90%)
x2 ¼ 12.451; df ¼ 1; p < 0.001; highly significant.
partially impacted, it can be imagined that the tension line will be disrupted, weakening the mandibular angle and making it more susceptible to fracture (Meisami et al., 2002). Consistent with other studies, the result of this study confirmed an increased risk of angle fractures when impacted third molars were present (Safdar and Meechan, 1995; Tevepaugh and Dodson, 1995; Lee and Dodson, 2000). In addition the present study showed that increased incidence of angle fracture is present when associated with impacted third molars in position A. Thangavelu and Yoganandha conducted a retrospective study and hypothesized that higher proportion of angle fracture was present in those with unerupted mandibular third molars. Condyle fracture was more common in those with erupted third molars. The highest incidence of angle fracture was observed in Class II ramus position, position B and mesioangular impacted third molars (Thangavelu and Yoganandha, 2010). Consistent with the above study, we observed increased risk of angle fractures when impacted third molars were present and increased risk of condyle fractures when impacted third molars were absent. In contrary, we found no significant relationship between ramus position and angulation of the impacted mandibular third molar to the incidence of angle fracture, but their incidence was high when specifically associated with impacted third molars in position A followed by position B. Some authors have postulated that the presence of impacted third molars (either partial or complete) reduces the incidence of condyle fractures (Zhu et al., 2005; Duan and Zhang, 2008). This study revealed that the highest incidence of condyle fracture was noticed typically in the absence of impacted third molars (either partial or complete). The present study demonstrated that in patients who had multiple fractures, when the unerupted third molars were present (either third molars were partially erupted or completely unerupted), the patient’s injuries were often associated with both parasymphysis and angle fractures. When the unerupted third molars were absent (either third molars were absent or completely erupted), the patient’s injuries were more associated with both symphysis and condyle fractures. This suggests that when the unerupted third molars were absent (either third molars were absent or completely erupted) much of the force may be transmitted to the condylar region; hence, the increased incidence of associated fractures of the condylar process. Kober et al. (Kober et al., 2001) proposed a biomechanical model that is in agreement with the findings of this study. They suggested that if the angle was weakened by incompletely erupted third molars, the possibility of condylar fractures would be decreased, as impact forces would be dissipated by the angle fractures. If the angle was intact, with no impacted third molars, it would be resistant to fracture and more impact forces would transmit to the condyle and result in fracture. 5. Conclusion
Fracture
Male
Female
Angle fracture Condyle fracture
62 (88.6%) 33 (82.5%)
8 (11.4%) 7 (17.5%)
x2 ¼ 0.797; df ¼ 1; p ¼ 0.372; not significant.
3
Various studies state that it might not be appropriate to strengthen the mandibular angle region and make the mandible vulnerable to condylar fractures by removing the unerupted third molars.
Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
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R. Gaddipati et al. / Journal of Cranio-Maxillo-Facial Surgery xxx (2014) 1e4
From this retrospective cohort, it can be concluded that the presence of an impacted third molar predisposes the angle to fracture and reduces the risk of concomitant condylar fracture. The highest incidence of angle fracture was observed in position A impacted mandibular third molars. There is no significant relationship concerning ramus position and angulation of impacted mandibular third molars with angle fractures. Sources of support None. Conflicts of interest None declared. References Archer W: Oral and maxillofacial surgery. Philadelphia: Saunders 1(5): 259e260, 311, 1975 Banks P, Brown A: Fractures of facial skeleton. St. Louis, MO: Butterworth-Heinemann, 2005 Chrcanovik BR, Abreu MHNG, Freire-Maia B, Souza LN: 1,454 mandibular fractures: a 3 year study in a hospital in Belo Horizonte, Brazil. J Craniomaxillofac Surg 40: 116e123, 2012 Duan DH, Zhang Y: Does the presence of mandibular third molars increase the risk of angle fracture and simultaneously decrease the risk of condylar fracture? Int J Oral Maxillofac Surg 37: 25e28, 2008 Huelke DF, Burdi AR, Eyman CE: Association between mandibular fractures and site of trauma, dentition and age. J Oral Surg 20: 478e481, 1962 Hwang K, You SH: Analysis of facial bone fractures: an 11 year study of 2,094 patients. Indian J Plast Surg 43: 42e48, 2010
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Please cite this article in press as: Gaddipati R, et al., Impacted mandibular third molars and their influence on mandibular angle and condyle fractures e A retrospective study, Journal of Cranio-Maxillo-Facial Surgery (2014), http://dx.doi.org/10.1016/j.jcms.2014.01.038
