DANB CRFDA common mistakes
DANB CRFDA · Understand the traps and how to avoid them.
Treating the rubber dam as optional during Class II and Class III direct restorative procedures, then answering questions as if isolation only matters for endodontics.
Candidates memorize rubber dam as an endodontic accessory and never connect it to moisture control, tissue retraction, and contamination prevention in operative dentistry.
What to do instead
Drill the rule that any adhesive-bonded direct restoration near the gingival margin requires field isolation; practice mapping which procedures demand rubber dam versus cotton roll isolation and why bonding to contaminated dentin fails.
Selecting a matrix system by habit (universal band on every posterior) instead of matching the matrix to the cavity class, contact location, and whether a wedge will be used.
Sectional matrices, circumferential bands, and wedge combinations are learned as isolated items rather than as decision points tied to proximal contour and embrasure form.
What to do instead
Build a decision table for Class II slot, Class II MOD, and deep subgingival margins, listing which matrix and wedge configuration restores contact and contour, then justify each choice in writing.
Describing the bonding sequence in the wrong order or skipping the etch-rinse-dry step for total-etch systems while applying self-etch steps to a total-etch product.
Manufacturers use overlapping terminology, and candidates blur total-etch, self-etch, and selective-etch protocols into one generic sequence.
What to do instead
Memorize each adhesive category as a numbered sequence (etch, rinse, dry, prime, adhesive, light) and rehearse the consequence of each omission, such as collagen collapse from over-drying etched dentin.
Placing increments of composite that are too thick and curing from a single direction, then defending the technique as adequate for any depth.
Candidates underestimate light attenuation through restorative material and do not connect increment thickness to depth of cure and polymerization shrinkage stress.
What to do instead
Learn maximum increment thickness per material shade and the inverse-square drop in irradiance with distance; state the clinical sign of undercure and the shrinkage consequence of bulk placement in a deep box.
Finishing and polishing with a single bur or coarse disc and calling the restoration complete, ignoring margin blending and proximal contour refinement.
Finishing is treated as cosmetic cleanup rather than a step that affects plaque retention, marginal integrity, and occlusion.
What to do instead
Sequence finishing from coarse to fine with named instrument categories, and explain how each stage reduces surface roughness, removes flash at the margin, and preserves contact form.
Checking occlusion only in maximum intercuspation and never in excursive movements or with articulating paper of appropriate thickness.
Candidates reduce occlusal adjustment to 'tap and check' and forget that lateral and protrusive contacts cause fracture and sensitivity in composite restorations.
What to do instead
State the full occlusal check sequence: static centric, lateral excursions both sides, protrusive, and verify marking with thin articulating film; explain why a heavy excursive contact on composite leads to chipping or fracture.
Confusing the expanded functions a chairside assistant may legally perform with those reserved for the dentist, and answering based on what happens in their own office rather than on scope-of-practice rules.
Delegation rules vary by state and by credential, and candidates generalize from a single employer's workflow instead of the statutory framework the exam tests.
What to do instead
Separate tasks into direct supervision, indirect supervision, and dentist-only categories, and note that final occlusal adjustment, diagnosis, and treatment planning stay with the dentist regardless of office custom.
Ignoring pulpal protection decisions, such as when to place a liner or base versus when to bond directly to a shallow preparation.
Candidates memorize materials without linking them to remaining dentin thickness and the risk of postoperative sensitivity or pulp insult.
What to do instead
Tie material choice to cavity depth: state the threshold for a protective liner, which materials are compatible under composite, and why eugenol-containing products are avoided beneath resin restorations.
Answering infection-control questions about restorative sessions with generic handwashing answers instead of addressing surface barriers, handpiece lines, and bur sterilization between patients.
Candidates compartmentalize infection control as a separate topic and fail to apply it to the restorative operatory's specific equipment and splash zones.
What to do instead
Walk through a restorative appointment as a sequence of barriers, flush, and disinfection steps, naming which items are single-use, which are barrier-protected, and which require sterilization.
Managing a failed or fractured restoration by describing replacement only, without assessing marginal breakdown, recurrent caries, or the reason the original restoration failed.
Candidates default to 'redo it' rather than diagnosing etiology, so they miss the preventive and material-selection reasoning the exam rewards.
What to do instead
Practice failure analysis: identify the cause (contour, occlusion, isolation, material), state what changes in the replacement plan, and explain how the chosen material and technique address that cause.