Abstract: Mandible is the only mobile bone of the facial skeleton that plays a major role in mastication, speech and deglutition. Among the maxillofacial trauma, mandible is the high risk exponent. Fractures of the mandible comprise between 40 and 62% of all of facial fractures. The purpose of this study was to evaluate the epidemiology of mandibular fractures in Qazvin province (1995-2005). In this descriptive and cross sectional study the charts of 204 patients with 304 mandible fractures treated at Rajaii and Ghods hospital were retrospectively reviewed. Age, gender and job of patients, etiology of fracture, treatment methods, site of fracture, type of radiography and seasonal Variation were recorded and inserted into spss software. Two hundred and four patients with 304 sites of fractures had refered to Rajaii and Ghods hospital. Data showed that 76% of all of patients were men and 39.7% of all patients were in the 21-30 years old age group. Occupationally, most of patients were workers (20.8%). The most common site of fracture was in body (41.77%) followed by the condyle (14.8%) and symphysis (14.15%). Car accident (37.1%) and motor accident (17.5%) was responsible for the majority of the fractures. About 69.2% of the patients sustained only one fracture and 30.8% of them sustained >1 fracture site. In this study panoramic radiography had been used commonly (89/2%). About 34.3% of the patients sustained other facial fractures and 28.9% sustained other injuries. The most common signs and symptoms were pain and swelling. The majority of fractures (31.4%) had happened in the summer. The finding of this study, compared with similar studies reported in the literature, support the View that pattern of mandibular fractures Vary form one country to another and as such can provide a guide to design of programs towards prevention and treatment. It is recommended to obey the traffic rules and make the drivers to use safety devices during driving.

INTRODUCTION

The daily increasing development and growth of industry, mechanization of life style is the reason for high number of car accidents and resulted injuries are severe and associated with fractures of different parts of the body. Among these, high percentage of patients have maxillomandibular fractures (Peterson et al., 2003).

In facial traumas, mandible is more vulnerable because of its position in the face (Abbas et al., 2003). Fractures of mandible constitutes 40-62% of all facial fractures. Gratten and Hobbs reported that 39% of car accident victims had facial injuries and among these 68% had fractures of mandible. Males are be affected 3-7 times more than females (Peterson et al., 1992). Fractures of mandible is diagnosed based on clinical signs such as pain, malocclusion, trismus, hemorrhage, ecchymosis, laceration, crepitation, fractured or extruded tooth, deviation when opening and closing mouth and radiological signs. Anatomical location of factures is largely dependent on mechanism of injury, socioeconomic conditions, racial and ethnic background (Kwon and Laskin, 2001).

In this study, the epidemiology of fractures of mandible in recent decades was surveyed (1995-2005) to provide precise and comprehensive statistical information so that accidents can be prevented, the complications and expenses can be reduced and the roads traffic condition can be improved.

MATERIALS AND METHODS

This research is a cross-sectional, retrospective and descriptive study. The medical records of the patients that referred to the hospitals of Ghazvin province between the years 1995-2005 were studied. The study was carried out using census sampling of the records of 204 patients with fracture of mandible. Informations including age, gender, domicile, job of patient, cause and location of fracture, symptoms, seasonal variation treatment methods, the type of Radiography and multiple fractures sites in the mandible were recorded in a form. Data were analyzed by descriptive statistics using SPSS software.

RESULTS

From the total 204 cases afflicted with mandibular fracture, 155 (76%) were male and 49 (24%) were female. The peak of incidence occured in the ages of 21-30 and the lower in ranks were 11-20 and 31-40. Most patients resided in city and the suburban areas. Occupationally, 20.87% workers, 20.32% self-employed, 19.8% students and 1.5% were soldiers. As to the time of the fracture, most of them happened in summer (31.4%) and next in rank were spring, fall and winter (19.6%). The type of X-ray requested in most cases were panoramic radiography (Table 1). Total requested radiographies were >100% due to overlapping of multiple requested X-rays. In other words, for each patient, >1 X-ray have been requested. From the total 304 fractures in 204 patients, the most common site of fracture was in body (41.77%) and next were Condyle and Symphysis (14/8%, 14/5%) (Fig. 1).

Table 1:	Distribution of mandibular fractures according to X-ray requested

Fig. 1:	Distribution of mandibular fractures according to site of fractures

About 56.4% of the fractures were unilateral and 27% were bilateral and 14.2% in the midline (symphysis). The prevalence of fractures of one area of mandible (69.2%) was more compared with two areas (28.9%) and three areas (10.9%). Unilateral fractures in the body was 71.65% and the bilateral fractures of the same area was 25.2%, the unilateral fractures of the Condyle was 64.25% and the bilateral ones of the same area was 33.34%. As to the frequency of double-area fractures, the combination of Symphysis and body fractures was more prevalent and next in rank was the combination of Condyle and body (Table 2).

Car accident (37.1%) and motor accident (17.5%) were responsible for the majority of the fractures (Fig. 2).

The most common symptom was pain (85.3%) and after that were inflammation, laceration, hemorrhage, loose teeth, limitation of jaw movement, tenderness and etc. (Table 3).

Synchronic fractures of body, alveolus and symphysis in 50% of the cases and fractures of condyle, body and alveolus and the fracture of condyle, body and ramus each with the frequency of 25% were the next ranks. From total 204 cases, 28.9% had injuries of other parts of the body (hand, foot, pelvis, etc.) from these, 70 persons (33.4%) had fractures of other parts of the face and 134 persons (65.7%) had fractures of mandible only.

Table 2:	Distribution of double-area fractures in mandible

Table 3:	Distribution of mandibular fractures according to signs and symptoms

Fig. 2:	Distribution of mandibular fractures according to cause of fracture

Treatment of mandible fracture was carried out with open reduction in 115 cases (56.4%) and with close reduction in 89 cases (43.6%).

DISCUSSION

In this study, the main cause of mandible fracture was motor vehicle accidents (motorcycle, car). Males share was more than females. There are significant differences in the patterns of maxillofacial fractures in different parts of the world. Data are different in different parts of the world based on habbits, socioeconomic status and racial and ethnic background (Peterson et al., 1992).

Anwar and Bataineh (1998), Azevedo et al. (1998), Dugan et al. (1998), Tan and Lim (1999), Tay et al. (1999), Wong (2000), Ogundare et al. (2003), Abbas et al. (2003), Oginni et al. (2006), Ansari (2004), Subhashraj et al. (2008), Qudah et al. (2005), Sakr et al. (2006) and Simsek et al. (2007), reported that most patients with mandibular fractures are male. The result of this study was similar to the result of previous studies in their respect. This may be due to the fact that men are more present in the society. Based on this study, most patients were in the age range of 21-30. This was similar to the results of studies conducted by Anwar and Bataineh (1998), Dugan et al. (1998), Tan and Lim (1999), Tay et al. (1999), Wong (2000), Abbas et al. (2003), Oginni et al. (2006), Ansari (2004), Subhashraj et al. (2008), Sakr et al. (2006). Azevedo et al. (1998), reported the age range of 16-20 as the most common age of mandibular fracture, perhaps due to a preassumptilon that fighting was the most common cause of the mandibular fractures.

About 20.87% of the patients were workers. Most patients were residing in Ghazvin city or its suburban areas. This indicates that these people are not familiar enough with safety rules of traffic, occupation and sport in these areas.

Based on this study, the most common cause of mandibular fracture was motor vehicles, which was compatible with surveys of Anwar and Bataineh (1998), Fasola et al. (2001), Tan and Lim (1999), Wong (2000), Ferreira and Amarante (2004), Abbas et al. (2003), Adebayo et al. (2003), Ansari (2004), Subhashraj et al. (2008), Qudah et al. (2005) and Sakr et al. (2006).

While, individual fights have been mentioned as the main cause of fracture in the reports of King et al. (2004), Ogundare et al. (2003), Azevedo et al. (1998) and Simsek et al. (2007).

This was different from the results of this study. The main cause of this difference is the fact that safety rules are less complied with by car drivers and motorcycle riders of developing countries compared with the developed countries. At present study, the cause of 2.1% of fractures was epilepsy. This indicates the necessity of complying with safety rules in these patients. Also, 1.5% of the patients had mandibular fracture at the time of tooth surgery. At present study most of the patient were treated with open reduction, similar to those carried out by Subhashraj et al. (2008), Sakr et al. (2006), Tan and Lim (1999) and Fasola et al. (2001) in Nigeria in their studies. May be, the main cause of this observation was the multiple maxillofacial fractures associated with other injuries outside the maxillofacial region that needed advanced treatment (Fonseca, 1997). In this study, the most common prescribed X-ray was panoramic. Based on the study, body of mandible showed the highest rate of fracture. This was compatible with the results of the studies conducted by Qudah et al. (2005), Fonseca and Walker (1997) and Fasola et al. (2001). While, the most common area in the studies of Tay et al. (1999), Ferreira and Amarante (2004) was condylar area. Wong (2000), Abbas et al. (2003), King et al. (2004) and Subhashraj et al. (2008) reported parasymphysis as the most frequent fracture in mandible. According to this study, 69.2% of cases had fracture of one area of mandible while, according to the studies of Ogundare et al. (2003), Tay et al. (1999) and Sakr et al. (2006), most patients had bilateral fractures or more anatomical regions were involved. Ogundare (2003) and Subhashraj et al. (2008), reported more fractures in the summer in their studies. This was similar to the results of this study which could be related to a higher traffic of motor vehicles in this season.

CONCLUSION

The results of studies about mandibular fractures are different from one society to other based on geographical, economic, cultural, social and religious conditions. In the under-observe society, the main cause of mandible fracture was motor vehicle accidents. Most patients were in the age range of 21-30 and males. Most accidents occurred during summer. Most patients were treated by open reduction method. Since, the main cause of these fractures proved to be motor vehicle accidents, any efforts made to enforce traffic and safety rules in the roads and improve traffic culture can be an effective measure to promote the present situation.

ACKNOWLEDGEMENT

We thank Dr. Leila. Mahdi Hadji mahmoudlou for their contributions.