Before we begin this session we must consider some basic dental anatomy. Teeth come in 4 main types, incisors, canines, premolar and molars, and are often “coded” for convenience.

The image below shows the notation. Each tooth type is given a number starting from the front and moving backwards. So the central incisor (very front tooth) is given a number one, the lateral incisor (the next tooth along) a number 2 and so forth. The number 3 is for canines, 4,5 for premolars, and 6-8 for molar teeth. The “quadrant” or “corner” the mouth is marked by the two perpendicular lines, with the horizontal and vertical line showing the tooth’s relationship to the midline of the mouth. Sometimes teeth may be marked as being “UL2 or LR3”. This is a shorthand method of denoting the “Upper Left 2” (UL2) or “Lower right 3” (LR3).

Decidious (baby) teeth are annotated differently, using letters instead of numbers.

Dental trauma is more common in patients who have a class 2 div 1 incisor relationship. Patients with this relationship have an increased overjet, which is when the top teeth are more anterior to the bottom teeth (see below, the blue arrow shows an average overjet, the red showing an increased overjet).

Taken from

The direction and amount of force will result in differences in the number of teeth affected and the type of injury sustained. Furthermore, younger patients will generally have softer bone, and in these age groups, avulsion of associated teeth is more likely. In older patient age groups, the bone tends to be more rigid, and therefore tooth fracture and alveolar bone fracture tends to be more likely.

Reference: Shulman-JD .And PetersonJ. : The association between incisor trauma and occlusal characteristics in individual’s 8-50years of age .Dent. Traumato. 2004. 20(2):67-72

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