Form ever follows function: the occlusal compass and direct resin composite restorations

It is the pervading law of all things organic and inorganic, of all things physical and metaphysical, of all things human and all things super-human, of all true manifestations of the head, of the heart, of the soul, that life is recognizable in its expression That form ever follows function. That is the law¹

The posterior direct resin restoration is the most common restoration carried out in general dental practice² and therefore consumes a large amount of a dentist's energy and time. A significant portion of the appointment time for direct resin restorations in the posterior dentition is spent on layering and contouring resin masses and final finishing with rotary instrumentation.

The majority of operators choose to layer their composite resin in its pre-polymerized state as a fairly amorphous mass with basic cuspal inclines, followed by contouring and polishing with burs, discs and points after polymerization. In recent years, more anatomical layering techniques have been proposed^3,4 which offer a more elegant solution to layering, however, they are based on layering the enamel masses to a preconceived aesthetic ideal. This means that the operator has an idea in his or her mind of the ideal occlusal anatomy (usually from textbooks of anatomy or, in Today's World, online learning) and then imparts this ‘one size fits all’ solution to each tooth. Whilst these approaches are simple to teach and easy to learn, they confer the following disadvantages: