CDTs

Contents of Five Practical Examinations

The National Board for Certification requires that all Certified Dental Technician candidates pass on-site practical examinations to demonstrate their competence over a range of procedures normally associated with their respective specialties. What follows here is a preview of the contents of each of the specialty tests.

In all specialties, four weeks prior to the test date the NBC mails candidates full detailed instructions together with molds which are used to prepare examination casts. Included in the candidates' instruction booklets are the complete standards by which their tests will be scored.

In addition to preparing casts for use at the on-site test, in all specialties except Orthodontics, there are several preliminary assignments—items which must be either partly or completely fabricated by the candidate in his or her laboratory and must be brought to the test site for further use.

All steps in the examination must be performed by the candidate, alone and without advice or assistance.

Removable Prosthodontics-Complete Dentures

In advance of the examination day, candidates must pour and mount casts on semi-adjustable articulators according to NBC instructions, and must setup and process a complete set of maxillary and mandibular dentures. At the test site, they will:

• Make and finish a maxillary custom tray;
• Arrange 1 x 28 anatomical teeth in full balance, using the previously mounted casts;
• Contour the 1 x 28 setup;
• Make two denture repairs (one tooth replacement and one fracture repair);
• Make a maxillary wax occlusal rim on a stabilized baseplate.

Candidates' grades are grouped into three sub-tests. One sub-test consists of the grades on the setup accomplished at the test site; another covers all of the preliminary procedures; and the third includes all other procedures on the examination. As in all of the certified specialties, candidates must achieve passing scores on all three sub-tests to qualify for certification.

Removable Prosthodontics-Partial Dentures

The preliminary portion of the Partial Denture examination requires candidates to pour several sets of casts, survey and design maxillary and mandibular frameworks, make refractory casts and make one chrome partial framework casting. At the test site, Partial Denture candidates are instructed to:

• Survey and design, according to given specifications, one maxillary and one mandibular framework and prepare the casts for duplication;
• Weld or solder a wrought wire clasp to a framework that is brought to the test;
• Make wax patterns on two refractory casts fabricated in the preliminary portion of the examination; and
• Finish and polish a casting that is brought to the test for this purpose.
• The grade on the partial denture examination consists of four parts, all of which must be passed to qualify for certification: (1) the preliminary work; (2) design; (3) waxing; and (4) metal work.

Fixed Prosthodontics-Crown & Bridge

In the preliminary part of this test, candidates must pour casts, fabricate individual removable dies and mount their casts on semi-adjustable articulators according to the written instructions. Candidates must also wax and cast a framework for a three-unit bridge, remove the sprues and seat the casting. They must also wax and cast an MOD inlay that will be finished at the test site.

On the day of the examination, candidates must wax a central incisor and a three-unit bridge. The three-unit bridge cast during the preliminaries will be segmented, and candidates must solder, finish and polish the bridge at the test site. They must also wax an MOD restoration and finish and polish the MOD cast previously.

Grades for this specialty are reported in three parts: (1) the preliminary assignments (including adherence to instructions); (2) the waxing assignments; and (3) all of the metal work.

Fixed Prosthodontics-Ceramics

Ceramics candidates pour casts, fabricate removable dies and identify marginal finish lines in advance of the examination. They are instructed to mount their casts on two semi-adjustable articulators. They also make a metal coping which is to be finished at the test site. Candidates must wax and cast the framework for a three-unit bridge; this framework is to be opaqued and ready to receive porcelain at the test site. Another metal coping is to be made and metal-finished.

At the test site, this latter coping is used to construct and finish a porcelain shoulder margin crown. The other coping is to be metal-finished. Candidates must complete a porcelain-fused-to-metal bridge on the framework they have brought to the test, and they wax one additional coping.

In the Ceramics test, candidates' grades are reported in three sub-tests: (1) the model and die work, metal finishing and waxing steps; (2) the three-unit PFM bridge; and (3) the porcelain shoulder margin crown.

Orthodontics

Prior to the examination, candidates in the Orthodontic specialty need only prepare their casts using the NBC test molds. All other assignments (the fabrication of three appliances) are done at the test site: one Hawley-type appliance, a modified mandibular unilateral sagittal appliance, and a mandibular lingual arch. Each appliance represents one sub-test score.

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