ORE Part 2 · Dental Manikin (DM) guide
Composite Cusp Build-Up
A fractured cusp restored in composite — bevelling the fracture, lining, then building the wall, marginal ridge and cusp in increments until the tooth's anatomy is reproduced. The challenge is building real cuspal form that follows the adjacent teeth, keeping a tight contact, and finishing with no overhangs or probe catches.
Our video demonstrates this on the mesiobuccal cusp of an upper first molar (26). In the exam, the tooth and exercise are set on the day.
What examiners look for
- A bevel around the fracture and cavity margins to give the composite surface area
- A lining placed only where it belongs — floor and step clear of the walls, no stray material
- A rebuilt cusp whose height follows the curve of Spee: taller than the premolar cusp, lower than the molar's distal cusp
- Buccal contour and cusp planes matched to the neighbouring teeth
- A reproduced occlusal anatomy — primary fissure, buccal groove and a marginal ridge of proper height and bulk
- A tight proximal contact that snaps floss, with no overhangs and no probe catches on any surface
Common mistakes
- Skipping the bevel, leaving the composite bonded to an unprepared butt joint
- Letting lining material stray onto walls and margins where the composite must bond
- Building the cusp as a shapeless mass and relying on burs to carve anatomy afterwards — build the anatomy in the composite before curing
- Overfilling the marginal ridge and creating a proximal overhang; remove excess with the probe tip before curing
- Damaging the gingiva or the adjacent tooth during finishing — discs and strips cut more than composite
What the official DM Guidance states
- A fractured cusp and cavity in an upper premolar or molar, restored and finished in composite
- Tooth preparation: rough fractured enamel margins smoothed, a bevel on the enamel margin, and unsupported enamel removed (not over-prepared, no excessive bevel or shoulder)
- A thin lining on the pulpal floor, if appropriate — not on enamel or extending to the cavity margin
- Incremental build-up of the bulk of the tooth, properly cured
- A smooth finish, with a contour continuous with the enamel that accurately restores the tooth's shape
- A tight contact point with the adjacent tooth, and no voids, defects or excess at the margin
The guidance gives no measurements for this exercise.
Source: ORE Part 2 Dental Manikin (DM) Guidance, version 2.0, effective 1 March 2026, p. 15–16. Values marked “about” are approximate in the guidance. Check the current version before your exam. How to reach these, step by step, is in the course.
Candidate questions
How do you judge the height of the rebuilt cusp?
From the adjacent teeth: the mesiobuccal cusp should sit a little taller than the premolar behind it and a little lower than the molar's own distal cusp, following the curve of Spee. The course video shows the sight lines to check this.
How do you avoid an overhang at the marginal ridge?
Shape the ridge and run the tip of the probe along the proximal margin before curing — once cured, an overhang is much harder to remove. A matrix strip held tightly against the tooth while you build does most of the work.
How much anatomy should be built versus carved?
As much as possible should be shaped in the soft composite — fissure, grooves and cusp planes — so finishing is only smoothing and polishing, not sculpture.