Candidates frequently ask what they can expect on the CDT examinations. While more information can be found in the CDT Handbook and Application or the RG Handbook and Application, including a breakdown of the content, we have attempted to provide you with an overview.
CDTs & RGs Written Exam Content
The Comprehensive and Recognized Graduate examinations measure for basic knowledge in history, ethics and the six specialties. These examinations consist of 160 multiple-choice questions, covering basic dental laboratory knowledge: oral anatomy, tooth morphology, materials science, health & safety, fundamental theory and terminology across the six specialties tested by the NBC. Each test item will consist of a question and four possible answers, or an incomplete statement and four possible ways to complete the statement. Of the four possible responses, the candidate must select the best answer. Candidates have up to 2 hours and 45 minutes to complete the examination; they may use as much or as little of this time as they require.
The CDT Written Specialty Examinations
The Written Specialty examination is a requirement for all CDT candidates. This exam tests a candidates' knowledge in his or her chosen specialty area. The different specialty areas offered are Ceramics, Complete Dentures, Crown & Bridge, Orthodontics, Partial Dentures and Implants. The Written Specialty examination consists of 80 multiple-choice questions. Each test item will consist of a question and four possible answers, or an incomplete statement and four possible ways to complete the statement. Of the four possible responses, the candidate must select the best answer. Candidates have up to 1 hour and 30 minutes to complete the examination; they may use as much or as little of this time as they require.
As part of NBC's ongoing efforts to ensure that the questions included in its written examinations are contributing to the reliability of the examinations, NBC includes an additional ten field test questions embedded on each examination form. These ten questions are not graded, but instead are used to gather statistical data to allow NBC to determine if the field test questions may be used on future examinations. Using field test questions is a common practice in the certification and licensure testing industry.
CDTs Practical Examination Content
The NBC requires that all CDT candidates pass a Hands-On Practical examination 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. We are pleased to announce changes to the Crown & Bridge, Ceramics and Implants practical examinations beginning January 1, 2017.
For examination specific changes to the Crown & Bridge Ceramics and Implants examination, please see below under the descriptions of each examination. For a general overview of all the changes regarding the NBC examinations (e.g. updated references, revalidated job task outlines, practical examination changes), please visit www.nbccert.org/news.
With all examinations, NBC ships the candidate detailed instructions together with molds which are used to prepare examination casts. This package will include an instruction booklet with the complete standards by which their tests will be scored. These are sent approximately four weeks prior to the exam date.
In addition to preparing casts for use at the on-site test, there are several preliminary assignments; items which must be either partly or completely fabricated by the candidate in his or her laboratory and then 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.
Candidates must achieve passing scores in all sub-tests of a specialty to qualify for certification.
In advance of the examination day, candidates must pour and mount casts on semi-adjustable articulators according to NBC instructions. They must then 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;
• Wax and Contour the 1 x 28 setup;
• Make two denture repairs (one tooth replacement and one fracture repair);
• Make a maxillary stabilized baseplate and wax an occlusal rim on it.
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.
The preliminary portion of the Partial Dentures 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, unfinished. At the test site, 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;
• Finish and polish the casting that is brought to the test site.
In the Partial Dentures test, candidates' grades consist of four parts: (1) the preliminary work; (2) design; (3) waxing; and (4) metal work.
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 fabricate a full contour three-unit metal bridge, which may be fabricated using traditional or digital methods, leaving it unfinished as specified in the written instructions.
At the test site, candidates will:
- wax a substructure.
- wax a full contour three-unit bridge.
- solder/laser weld, finish and polish the segmented 3-unit bridge.
In the Crown & Bridge test, candidates' grades are reported in three parts: (1) the preliminary assignments; (2) the waxing assignments; and (3) the metal work.
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 fabricate a metal coping and a three unit-substructure using the material of their choice. Coping and substructure may be fabricated using traditional or digital methods and should be finished as specified in the written instructions.
At the test site, candidates are instructed to complete:
- a wax pattern for a veneer.
- a PFM crown with porcelain butt margin.
- a three unit posterior bridge.
In the Ceramics test, candidates' grades are reported in in three parts: (1) the model and die work, metal finishing and waxing steps; (2) the veneer and the PFM crown; and (3) the three unit bridge.
Prior to the examination, candidates in the Orthodontics 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
• One removable modified mandibular unilateral sagittal appliance
• One fixed mandibular lingual arch.
In the Orthodontics test, candidates' grades are reported in four parts: Each appliance represents one sub-test score and candidates are graded on preliminary work.
In the preliminary part of this test, candidates must pour casts, with appropriate soft tissue material, for both fixed and removable tasks according to the written instructions. They will be required to construct a custom abutment which may be fabricated using traditional or digital methods. Candidates are also required to construct a baseplate over attachments and a verification jig to fit a multi-implant situation according to the written instructions.
At the test site, candidates are instructed to complete:
- a full contour wax up over a custom abutment.
- a matrix and a full contour wax up for a screw retained bridge.
- a stable wrap-around bar substructure to fit the provided stent.
- a 1 x 14 set up and wax up over attachments.
In the Implant test, candidates' grades are reported in three parts: (1) the preliminary assignments; (2) the screw retained and cement retained assignments; and (3) the bar design and the 1x14 set up and wax up assignments.
Written Exam Appeal Policy
If a person taking the written exam believes that they were in an unsatisfactory testing environment or experienced unfair treatment, they can either submit a verbal complaint to the Proctor at the test site or send a written complaint to the NBC Headquarters. The Proctor is to write up the complaint and submit it to the NBC along with their comments.
You must also notify NBC headquarters in writing of your request for a procedural appeal within 48 hours (or two business days) after the test date.
Your written request for appeal should include a detailed description of the event, circumstance, or procedure that affected your performance on the examination.
If a candidate feels there has been an error in reporting the reading of the answer sheets, the candidate should submit a written request for a score review to verify accuracy in the calculation. If accurate, grades will not be altered.
All grade appeals must be received in writing by the NBC headquarters within four weeks of the test date.
For all CDT written examinations, a candidate is allowed to make comments pertaining to the examination items. A special form is provided to all written examination candidates at the test site for them to document this feedback.
Comments will only be accepted by candidates if they turn in this documentation at the examination site. All comments are reviewed by subject matter experts, designated by the appropriate examination committee, throughout the year. While responses to comments are not provided back to the candidate, the comments will be used to help ensure the maintenance of the examinations.
Updated August 2012
Practical Exam Appeal Policy
If you believe, and can provide, valid evidence that any circumstance, event, or procedure at the test site had an adverse effect on your ability to successfully complete the practical examination or that you experienced unfair treatment or grading, please let the Lead Examiner know immediately before you leave the test site. The Lead Examiner will log your initial comments and return them to NBC headquarters. If you are uncomfortable speaking with the Lead Examiner, you should speak to one of the other Examiners. Either way, a written complaint must be created at the test site. Any comments regarding circumstances, events, or procedures at the test site that are not logged with an Examiner at the test site will not be considered for appeal.
You must notify NBC headquarters in writing of your request for appeal within two weeks of the test date. Your written request for appeal should include a detailed description of the event, circumstance, or procedure that affected your performance on the examination.
The complaint and supporting information shall be reviewed to determine if unsatisfactory examination conditions did exist. Upon determination that a candidate did not have a "fair" opportunity to take the practical exam under acceptable conditions, a solution will be developed with the candidate based on the particular situation. If it is determined that the conditions were acceptable, the candidate has the option to appeal to the Board of Trustees.
Candidates who take the practical examination receive a detailed written report of the percentage grades assigned to each evaluated aspect of their test materials. If a candidate feels there has been an error in reporting the percentage grade for one or more specific line items in the report, the candidate should submit a written request for a score review to verify accuracy in the calculation and reporting of the specific line item(s). If accurate, grades will not be altered but the candidate may appeal for a retake.
Consideration of grade appeals will NOT include requests for additional points, exceptions or revisions to the standards, or re-submission or re-evaluation of examination assignments that have been removed from the security of the test site.
All appeals must be received in writing by the NBC headquarters within two weeks of the test date.Updated August 2012
If you need to retake an examination, please use the following, easier applications: