A new classification for crown fractures of teeth.

The aim of this work is to define a classification for traumatic injuries to crowns of teeth that offers a simplified interpretation, which can be communicated easily. These data will help us to evaluate the future restorations (composite resins, crowns, porcelain veneers) according to the variable design and extension of initial crown fracture lines. For this reason we conducted research on a vast sample of subjects, who presented different traumatic lesions, in order to obtain a specific selection of these typologies of injuries. We reviewed the literature for a complete, brief classification of simple use, which could serve our cause. The traditional classifications (Andreasen, Ellis, OMS) did not satisfy us for different reasons. In fact, they only consider the initial lesion situation, never focusing on the shape of the lesion and therefore never giving suggestions for the best kind of material for restoration. On the contrary, our interest is to define the kind of more valid materials according to the variable design of crown fracture lines, to foresee the duration of these materials and the best time to substitute them. To simplify and make our research a more affordable one, we created a 4 classes classification (A-B-C-D) and 3 subclasses (b1-c1-d1). Class A: all the simple enamel lesions which involve a mesial or distal crown angle, or only the incisal edge; Class B: all the enamel-dentin lesions, which involve a mesial or distal crown angle and the incisal edge. When a pulpal exposure exists we define it a Subclass b1; Class C: all the enamel-dentin lesions, which involve the incisal edge and at least a third of the crown surface. When a pulp exposure exists we define it a Subclass c1. Class D: all the enamel-dentin lesions, which involve a mesial or distal crown angle and the incisal or palatal surface, with root cement involvement (crown-root fractures). When a pulpal exposure exists we define it a Subclass d1. This classification showed how different kinds of lesions (Class B, b1, C and c1, in our new classification) fall under the same definition (enamel-dentinal fractures) in traditional classifications (Andreasen, Ellis). However, they need a wholly different clinical approach, and the material involved in the treatment shows different behavior and duration. This new classification simplified the gathering of data and the communication among practitioners, thus confirming its importance in getting optimal diagnostic and therapeutic protocols. It also allowed us to identify the most frequent crown fractures (Class B, b1 and C, c1) that in our sample of patients (age range: 8-18) are typically treated with composite resins or original fragment reattachment technique. All these studies brought us to develop this new "easy to use" classification of dental crown lesions that helped us to gather data easily, to choose the right materials to improve the communication among practitioners including by electronic means,