In preschool children, head and facial injuries make up 40% of all injuries and oral injuries are covering as much as 18% (1). Andreasen et al. (2) report that one third of 5 year-old children have history of dental trauma, and a large proportion of minor traumatic injuries to deciduous teeth are not reported and not taken into account in the statistics (3). Predominantly deciduous maxillary central incisor teeth are involved, lateral incisors to a less degree and canines (4). The peak prevalence of injures to milk teeth occurs at 2-3 years of age, when motor coordination is still during development, but increased physical activity in children is observed (5). Most frequent trauma to primary dentitions are injures to the supporting tissue i.e. luxations, which account for between 21 and 81% of all dental trauma (3). Multiple luxation injuries and trauma to surrounding soft tissues are mainly reported in children 1-3 years of age and are typically as a result of falls (1). Whereas, isolated root fractures are rare entity among trauma to primary teeth. According to Andreasen and Andreasen (6), in primary dentition 2-4% of dental traumatic injuries were reported as root fractures. Similarly, Walczak et al. study (4) report that root fractures were observed in 2. 46% of dental trauma in children under the age of 6 years. The difference in the trauma pattern favoring luxation rather than fracture has been found to be typical for the primary dentition, since the surrounding bone is less dense and less mineralized and elasticity of the alveolar bone surrounding the primary teeth is high, also primary tooth held in alveolar socket is less strong. This is also due to teeth anatomy as deciduous teeth have shorter crowns than counterpart permanent teeth and roots have smaller sizes (3).

Incidence of foot fractures increases at the age of 3-4 years where physiologic root resorption has begun, thereby weakening the root (7). Root fractures are defined as fractures involving dentin, cementum, and pulp, without or with displacement of coronal fragment of the root. In a clinical examination, the coronal fragment is usually mobile and dislocated, transient pink or gray discoloration of the crown may appear (2, 8). Root fractures in the primary dentition are usually located at mid-root or in the apical third, with radiolucent lines separating the root into two or more fragments (8, 9).

A 3-year-old boy was brought by his mother to the Department of Paediatric Dentistry Medical University of Łódź on 20^th November, 2014, complaining of pain and increased mobility of the central incisors in the maxilla following dental injury on the day of reporting. Written consent from subject’s parents/subject’s legal guardians was obtained. The mother of the child reported that the injury was caused by falling to the floor while playing at home. A first aid in the form of stopping of bleeding from the injured upper lip was given immediately after the trauma. Intraoral examination revealed upper lip edema and the presence of a wound of the upper lip, but no suturing was required. In the intraoral examination, hematoma of the alveolar mucosa in the region of primary tooth 51, extrusion and palatally displacement of the tooth were found. The right central maxillary incisor exhibited vertical and horizontal mobility > 2 mm (class III mobility). Also, fracture of the crown, involving enamel, and increased mobility of the left maxillary incisor, 61 were found. Radiographic examination revealed a horizontal fracture on the left central incisor at the apical third of the root, increased periodontal ligament space apically due to severe extrusion of tooth 51 and shortening of the tooth on X-ray due to its palatal displacement (fig. 1). Since severe displacement in the fully formed primary tooth 51, extraction was the treatment of choice, what was in accordance with IADT (The International Association of Dental Traumatology) guidelines for management of traumatic injuries to primary teeth (1).

The patient was referred to the Surgical Department, where the tooth 51 was extracted. Due to the extensive mobility and extrusion, the procedure was performed under topical anesthesia.

A follow-up appointment was set, the patient was instructed to remain on a soft diet for 2 weeks and a gentle brushing with a soft brush was recommended. During the control visit on 24^th November, 2014 the tooth mobility was reduced, crown color was normal and there were no changes on alveolar mucosa in the region of tooth 61. The patient’s mother was informed about the need of clinical and radiological follow up. Also, at 8 weeks, the tooth 61 was asymptomatic, physiological mobility and no crown discoloration and normal oral mucosa were noted. Radiographic examination showed resorption on distal surface of apical fragment, rounded margins of coronal fragment of the root, and no evidence of any inflammatory process in the affected tooth (fig. 2). Presence of root fracture healing with calcified tissue was found at the 8 month follow-up (fig. 3).