The NBDE Test Guide

The NBDE Test Summary
What: Examinations that prepare a dentist for licensure.
Who: Prospective dental professionals.
Where: Tests are administered at Thomson Prometric Testing Centers.
When: Year round.
How: Computerized.
Type: On computer.
Why: To practice dentistry.
Time: NDBE I takes an entire day; NDBE II lasts one-and-one-half days.
Language: English.
Preparation: NDBE is typically taken by graduating dental students with extensive knowledge of natural sciences.
Cost: NDBE I - $265, NDBE II - $345.

The National Board of Dental Examinations (NBDE) are assessments that a prospective dental professional must pass in order to become a licensed dentist.


The NBDE I includes 400 multiple choice questions covering four general subject areas: anatomic sciences, biochemistry/physiology, microbiology/pathology, and dental anatomy and occlusion. Each area is represented equally with approximately 100 questions on each subject.

The NBDE I is administered year round via computer at Thomson Prometric Testing Centers, although a written form of the examination is available, generally given twice a year. The cost for a computerized test is $265. Dental students are eligible to take the exam once they have completed all NBDE I prerequisites as determined by their dental school, usually during the second year of study.

Test takers can expect to devote an entire day to the examination. Sign-in and instruction lasts 30 minutes, after which the anatomic sciences and biochemistry/physiology sections are administered. This first exam period lasts 210 minutes, and students may devote as much time to either section as they choose. After this exam period finishes, a lunch break will be given that lasts no more than 60 minutes. Individual proctors may assign shorter lunch breaks.

The final period of the NBDE I is made up of the microbiology/pathology and dental anatomy and occlusion sections. Once again, a 210 minute block of time is assigned for students to use as they see fit.

Anatomic sciences consists of several subsections which the test taker should be familiar with: gross anatomy (with special concentration on the head and oral cavity), histology, oral histology and developmental biology.

The biochemistry/physiology section includes questions on the following subsections: biological compounds, metabolism, molecular and cellular biology, connective tissues, membranes, nervous system, muscle, circulation, renal, oral physiology, digestion and endocrines. It is administered simultaneously with the anatomic sciences section, and both are to be finished within 210 minutes.

Microbiology/pathology is composed of questions regarding: general microbiology, reactions of tissue to injury, immunology, pathology of specific diseases, systemic pathology and growth disturbances.

Finally, dental anatomy and occlusion consists of: tooth morphology, pulp cavity morphology, calcification and eruption, principles of occlusion and function, and clinical considerations. This section is given alongside microbiology/pathology, with 210 minutes to complete both sections.


The NBDE II is an even more comprehensive evaluation than the first test. It is made of 500 test items: 400 discipline-based questions plus 100 case-based items. All questions are multiple choice format, and the testing schedule is set up very similar to the NBDE I. The first day consists of two discipline-based sections, each composed of 200 items, and each lasting for 210 minutes. A one-hour lunch break is scheduled to break up each session. The following day, the 100 case-based questions will be given during another 210 minute session. The fee for taking the NBDE II is a non-refundable $345. Dental students typically take this exam during their final year of dental school.

The discipline-based sections are composed of nine separate subject areas, scattered randomly throughout the 400 items. These subject areas include: endodontics, operative dentistry, oral and maxillofacial surgery/pain control, oral diagnosis, orthodontics/pediatric dentistry, patient management, periodontics, pharmacology and prosthodontics. All 400 multiple choice questions are administered over seven hours on the first day.

On the second day, 100 case-based items are given. The section is divided into two main segments: one is a Booklet of Cases, in which hypothetical patient information, dental charts and x-rays are provided for the test taker; the second segment requires the application of this raw information to answer various questions about the patients. Ten to fifteen questions will be given for each patient from the Booklet of Cases, requiring the test taker to interpret findings, make diagnoses, evaluate progress and treatment and establish procedures for prevention and maintenance. Approximately 70 percent of the patient cases will involve adults and the remaining 30 percent child patients. As per the other two sections, 210 minutes are given to complete the case-based items.

As with any exam, be aware of the test center’s policies and rules, and do not bring any banned materials into the exam site such as notes, calculators, pens, or phones.

If you are planning on taking the NBDE I or NBDE II, take a look at our NBDE Test Directory of test prep information and resources.

Source: American Dental Association; ada.org