The aim of this retrospective study was to clarify the occurrence and types of dental injuries in 389 patients who had been diagnosed with facial fractures, and to analyze whether the occurrence of dental injury correlates to gender, age, trauma mechanism and type of facial fracture. Dental injuries were observed in 62 patients (16%). The most common type of injury was a crown fracture (48%). Dental injuries were multiple in most patients (63%). Almost half (48%) of all injured teeth were severely injured. Most injured teeth (61%) were in the maxilla. The incisor region was the most prevalent site in both the mandible (45%) and the maxilla (56%). The occurrence of dental injury correlated significantly with trauma mechanism and fracture type: motor vehicle accidents and mandibular fracture were significant predictors for dental trauma. The notable rate of dental injury observed in the present study emphasizes the importance of a thorough examination of the oral cavity in all patients who have sustained facial fracture. Referral to a dental practice for further treatment and follow up as soon as possible after discharge from hospital is fundamental.
In addition to bruises, haematomas and wounds, dental injuries are the most common injuries occurring in the facial region. About 50% of patients who seek treatment for different types of facial injuries have sustained dental trauma .
Several studies have focused on the epidemiology and types of isolated dentoalveolar injury, and based on these investigations the following conclusions can be made: dental injuries usually occur in children and adolescents ; boys sustain these injuries more often than girls ; the accidents take place most often at home or in school ; and causes of trauma are mainly falls . Anterior maxillary teeth are usually involved. Subluxation is the most common type of injury in the primary dentition, and uncomplicated crown fracture is most frequent in permanent dentition .
The pattern and severity of dental injuries in patients who have isolated injury of the dentoalveolar complex are presumably different from those in patients who have a combination of dental injury and major facial injury (i.e. fracture of facial bones). Patients with facial fractures are on average far more severely injured, fairly frequently presenting with concomitant brain injuries or other major injuries outside the facial region . The reason for this is that patients with facial fractures have sustained their injuries through high-speed impacts far more often than patients who have dental trauma . It can be assumed that a significant proportion of patients presenting with facial fracture also have dental trauma.
The main aim of the present study was to investigate the occurrence and types of dental injuries in patients who have sustained fractures of the facial bones. An additional aim was to clarify whether the occurrence of dental injury correlates with gender, age, trauma mechanism and type of facial fracture.
Materials and methods
Patients who had been diagnosed with maxillofacial injuries between 1 January 2003 and 31 December 2004 at the Department of Oral and Maxillofacial Surgery, Helsinki University Central Hospital, Finland were identified from the hospital database. Files of patients who had sustained fractures of the facial bones were included in the study, those of patients who had sustained isolated injuries of the dentoalveolar complex were excluded. Three hundred and eighty-nine patients fulfilled the inclusion criteria.
The outcome variable was any kind of dental injury (DI). The predictor variables were gender, age, mechanism of trauma, and fracture type. DI was classified according to type, severity and location based on the entries in the patient files. Type of DI was classified as: 1, crown fracture; 2, root fracture (with or without associated crown fracture); 3, concussion (sensitivity to touch or percussion but without mobility); 4, subluxation or luxation (mobility without displacement or with displacement labially, lingually or laterally); 5, extrusion (partial displacement of tooth out of its socket); 6, intrusion (displacement of tooth into its socket); and 7, avulsion (complete displacement of tooth from the socket). Root fracture, subluxation/luxation, extrusion, intrusion, and avulsion were considered severe DI. Site of DI was classified as mandibular or maxillary and further classified as incisor, canine, premolar, or molar.
According to age at the time of the injury, patients were classified as being children (12 years or less), teenagers (13–19 years) and adults (20 years or more). Adult patients were further classified into age groups 20–29 years, 30–39 years, 40–49 years, 50–59 years, 60–69 years, 70–79 years, and 80 years or more.
Mechanism of trauma was classified as fall on the ground, fall from height, bicycle accident, motor vehicle accident (MVA), assault, sport, and being hit by an object.
For each patient one of the following seven groups of fracture types was assigned: exclusively mandibular fracture (one or more); exclusively zygomatico-orbital fracture (i.e., tripoid zygomatic fracture or isolated zygomatic arch fracture); exclusively orbital fracture (i.e. isolated orbital floor, medial wall or roof fracture); exclusively nasal fracture; severe midfacial fracture (i.e., Le Fort I-III, naso-orbito-ethmoidal or multiple midfacial fracture); exclusively upper third fracture (i.e. fractures of the frontal sinus or skull base); or combined fractures (i.e. mandibular plus midfacial fracture, midfacial plus upper third fracture, mandibular plus upper third fracture, and panfacial fracture extending to all facial thirds).
Descriptive statistics were registered for all predictor variables. In the data analysis the correlation between DI and predictor variables was analyzed. Predictor variables were grouped as categorical variables and analyzed using the χ 2 -test. For patients’ age (years), analysis of variance was used to assess the statistical significance between groups. P values less than 0.05 were considered to indicate statistical significance.
The descriptive statistics of the 389 patients are shown in Table 1 . Most (79%) were male. The age range of the patients was 10.7–84.4 years (average 39.1 years). The largest age group was patients aged 20–29 years (23%) and only 0.5% of the sample was children. Assault was the most common mechanism of injury (44%). The commonest fracture types were exclusively mandibular fracture (34%) and exclusively zygomatico-orbital fracture (33%).
|Mechanism of trauma|
|Fall on the ground||76|
|Fall from height||23|
|Hit by object||13|
|Type of fracture|
|Exclusively upper third||7|
DI was observed in 62 (16%) patients. 158 injured teeth were observed, giving an average of 2.5 injured teeth per patient in 62 patients. In 23 patients only one tooth was injured, whereas 15 patients had 2 injured teeth, 10 patients had 3 injured teeth, 6 had 4 injured teeth, and 8 patients had 5 or more injured teeth.
Table 2 summarizes the types and sites of DI. Of 158 injured teeth, the most common type of injury was a crown fracture, observed in 75 teeth (48%), followed by subluxation or luxation in 39 teeth (25%), and root fracture in 23 teeth (15%). 76 teeth (48%) were severely injured. Most injured teeth (96 teeth, 61%) were situated in the maxilla. Most crown fractures (63%), root fractures (61%), avulsions (67%), intrusions (100%), and concussions (100%) were observed in the maxilla, whereas most subluxations/luxations (51%) and extrusions (67%) occurred in the mandible. Most DIs (52%) occurred in the incisor region, with this region being the most prevalent site in both the mandible (45%) and in the maxilla (56%). In the mandible, the molar region was also frequently involved (36%).
|Site of DI||Type of DI|
|Crown fracture||Subluxation or luxation||Root fracture||Avulsion||Extrusion||Intrusion||Concussion||Total|
|Mandible||( n = 28)||( n = 20)||( n = 9)||( n = 3)||( n = 2)||( n = 0)||( n = 0)||( n = 62)|
|Maxilla||( n = 47)||( n = 19)||( n = 14)||( n = 6)||( n = 1)||( n = 2)||( n = 7)||( n = 96)|
|Total||( n = 75)||( n = 39)||( n = 23)||( n = 9)||( n = 3)||( n = 2)||( n = 7)||( n = 158)|
Figure 1 shows the respective proportions of injured mandibular and maxillary teeth for each fracture type. In association with most fracture types, DI occurred predominantly in the maxilla. In association with exclusively mandibular and exclusively orbital fractures, most injured teeth were found in the mandible, but the predominance was not strong (54% and 54%, respectively).
Table 3 summarizes the relationship between DI and gender, age, trauma mechanism and fracture type. No statistically significant difference in the occurrence of DI was observed between males (16%) and females (15%). The average age for patients with DI was lower (34.5 years) than that of patients who did not have DI (39.8 years), but the difference was not statistically significant. Nor were any statistically significant differences in the occurrence of DI observed when the age groups were compared with each other.