How Many Biology Credits Do You Need for Dental Hygiene School-most CODA-accredited dental hygiene programs require 12–16 biology credits before you can apply, broken across three or four specific courses: General Biology (4 credits), Anatomy and Physiology I (4 credits), Anatomy and Physiology II (4 credits), and Microbiology (4 credits). Some programs require all four; many require A&P I/II and Microbiology and treat General Biology as a recommended preparation course; a few high-demand programs require additional upper-division biology coursework, pushing the total to 20+ credits
This guide walks through exactly what each program requires, how the biology credit count breaks down across required courses, why programs structure their requirements the way they do, and how to choose accredited prerequisite coursework that every dental hygiene admissions committee in the country will accept.
| Quick answer: dental hygiene biology credit requirements• Typical CODA program total: 12–16 biology credits across 3–4 courses• Always required: Anatomy & Physiology I + II (8 credits) and Microbiology with lab (4 credits) = 12 credits minimum• Frequently required: General Biology I with lab (4 credits), bringing the total to 16 credits• Lab requirement: Virtually every program requires biology courses to include lab components on the transcript• Recency rule: Most programs require biology coursework completed within 5–7 years of application; some allow up to 10 years• Minimum grade: Most programs require a C or higher in every biology course; competitive applicants earn B+ or better |
The biology credit total isn’t a single course — it’s a stack of three or four specific courses that every dental hygiene program expects you to complete before you apply. Here’s the full breakdown:
| Course | Credits | Required by | What it covers |
|---|---|---|---|
| General Biology I (with lab) | 4 credits | ~60% of programs | Cell biology, genetics, evolution, foundational concepts |
| Anatomy & Physiology I (with lab) | 4 credits | Virtually all programs | Skeletal, muscular, integumentary, nervous systems |
| Anatomy & Physiology II (with lab) | 4 credits | Virtually all programs | Cardiovascular, respiratory, digestive, endocrine, urinary, reproductive systems |
| Microbiology (with lab) | 4 credits | Virtually all programs | Bacteria, viruses, fungi, oral pathogens, infection control |
| TOTAL (typical) | 12–16 credits | — | Complete biology foundation for CODA Standard 2-8b biomedical content |
The three courses highlighted above — A&P I, A&P II, and Microbiology — are the non-negotiable core. Almost every CODA-accredited dental hygiene program requires all three, and the lab component is required for each. General Biology I is required by the majority of programs but treated as a recommended preparation course at others, especially those that allow direct entry into A&P I.
Dental hygiene programs don’t pick prerequisites at random. Every required biology course connects directly to the curriculum content that the Commission on Dental Accreditation (CODA) requires every accredited program to deliver. Specifically, CODA Standard 2-8b requires every dental hygiene program to teach “anatomy, physiology, chemistry, biochemistry, microbiology, immunology, general and maxillofacial pathology and/or pathophysiology, nutrition and pharmacology.”
Programs build their prerequisite biology requirements backward from this standard. They expect students to enter the program already understanding the foundational anatomy, physiology, and microbiology — so the program itself can layer on the dental-specific content (oral anatomy, oral microbiology, periodontology, oral pathology) without having to re-teach the basics.
General Biology I — the foundation
General Biology I covers the cellular, molecular, and genetic foundations that everything else builds on. Cell membrane transport explains how local anesthetics work. DNA structure explains why some patients are genetically predisposed to periodontal disease. Mitosis explains how oral tissues regenerate after scaling and root planing. Without this foundation, A&P concepts feel like memorization instead of reasoning.
Some programs allow students to skip General Biology if they took it in high school and scored well on the AP Biology exam, or if they’ve completed an upper-level biology course. Most programs, however, require a college-level General Biology course on the transcript with a lab component — even for students with strong high school backgrounds.
If you haven’t taken college-level biology yet, BIO 135 Principles of Biology I at PrereqCourses.com is a 4-credit, fully online course with embedded lab activities, accredited through Upper Iowa University. It satisfies the general biology prerequisite at every dental hygiene program that accepts coursework from regionally accredited institutions.
Anatomy & Physiology I and II — the largest single requirement
A&P I and A&P II together account for 8 of the 12–16 biology credits required, making this sequence the single largest piece of your prerequisite biology stack. Every CODA-accredited dental hygiene program requires both semesters with labs.
The reason A&P is non-negotiable: dental hygienists treat the oral cavity in the context of whole-body health. A patient with uncontrolled diabetes presents differently than a patient with controlled diabetes. A patient on anticoagulants requires different scaling protocols. A patient with a history of bisphosphonate therapy carries risk of medication-related osteonecrosis of the jaw. None of this makes sense without a working knowledge of cardiovascular physiology, endocrine function, blood coagulation, and bone remodeling — the core content of A&P I and II.
A&P is also the course where most applicants either secure their admission or lose it. Programs use A&P grades as a primary indicator of academic readiness for the rigor of the dental hygiene curriculum, and many use A&P I grade explicitly as a tiebreaker when applicants have similar overall GPAs.
The PrereqCourses A&P sequence — BIO 270 Human Anatomy and Physiology I and BIO 275 Human Anatomy and Physiology II — is a 4-credit-each, fully online sequence with virtual lab components, accredited through Upper Iowa University. The complete sequence runs $1,390 and is accepted at every dental hygiene program that accepts regionally accredited prerequisite coursework.
Microbiology — the most dental-specific biology course
Microbiology is arguably the most directly relevant prerequisite biology course for dental hygiene. The oral cavity hosts more than 700 species of microorganisms, and biofilm formation on teeth is the central pathological process that dental hygienists are trained to interrupt. Periodontal disease, dental caries, oral candidiasis, herpetic infections, and the spread of bloodborne pathogens through aerosol-generating procedures are all microbiological problems.
CODA Standard 2-8b explicitly names microbiology as required curriculum content, and the standalone microbiology prerequisite ensures every entering student already understands the foundational concepts — bacterial structure, growth requirements, antibiotic mechanisms, sterilization techniques — before tackling the program’s oral microbiology and infection control content.
The lab requirement for microbiology is universal across CODA programs. Programs need to see that you’ve performed bacterial cultures, gram stains, and antibiotic sensitivity tests before they admit you. BIO 210 Microbiology with Lab at PrereqCourses.com is a 4-credit, fully online course with virtual lab activities that satisfies this requirement at every CODA-accredited program that accepts regionally accredited prerequisite coursework.
The 12–16 credit range is a useful generalization, but specific programs vary in interesting ways. Here’s how five different CODA-accredited programs structure their biology prerequisites:
University of Maryland — 16 credits minimum, 20 recommended
The University of Maryland Dental Hygiene Bachelor of Science program requires a minimum of 16 science credits, with 20 credits highly recommended. Their biology prerequisites include General Biology with lab (4 credits), Anatomy & Physiology I with lab (4 credits), Anatomy & Physiology II with lab (4 credits), and Microbiology with lab (4 credits). All science courses must be completed within 7 years of application, and all must earn a grade of C or higher — no lower grades accepted, no exceptions.
Maryland’s policy is representative of the more rigorous bachelor’s-level CODA programs: they want all four biology courses, they want them all with labs, they want them recent, and they want them taken at a regionally accredited institution.
CUNY City Tech — A&P I/II as the gateway, 5-year recency
The CUNY City Tech Dental Hygiene program structures its biology requirements around A&P I and A&P II as the entry gateway into the clinical phase of the program. Students who don’t have a strong high school biology background are required to take BIO 1101 (introductory biology) before they’re allowed to enroll in A&P I — adding a fifth biology course to the sequence for those students.
City Tech enforces a strict 5-year recency rule on all preclinical science courses (A&P I, A&P II, and Chemistry). Career changers who took A&P more than five years ago need to retake it before applying, regardless of how well they did the first time.
Northern Virginia Community College — 10-year recency, B+ grade requirement
The Northern Virginia Community College Dental Hygiene program requires General Biology I (BIO 101) as a prerequisite for A&P, plus Microbiology for Health Sciences (BIO 150) with a grade of B or higher. Their recency rule is more generous than most — 10 years rather than the typical 5–7 — but their grade requirement is stricter, requiring a B in microbiology rather than the C floor that most programs accept.
The pattern across all five programs
Despite the variation in specific course numbers and credit counts, every CODA-accredited program structures its biology prerequisites around the same four-course core: General Biology, A&P I, A&P II, and Microbiology. The differences come down to:
If you took your biology coursework more than 5 years ago, you have a problem. The majority of CODA-accredited dental hygiene programs require science prerequisites — including all biology courses — to have been completed within 5 years of application. Some programs allow 7 years; a few allow 10. But the science recency rule is one of the most consistent and least-flexible policies across the dental hygiene admissions landscape.
The reasoning is straightforward: biology, anatomy, and microbiology evolve fast. The microbiome content taught in a 2014 microbiology course bears little resemblance to current understanding. The CRISPR and epigenetics content in current biology curricula didn’t exist in older courses. Programs want to ensure entering students have current knowledge, not 15-year-old fundamentals.
| Career changer reality checkIf you earned a bachelor’s degree more than 5 years ago and took your biology courses then, you almost certainly need to retake them. This affects a huge number of dental hygiene applicants — career changers from business, education, communications, and other non-science fields whose original biology and chemistry courses are 8, 10, or 15 years old.The good news: retaking biology prerequisites at PrereqCourses.com costs a fraction of what re-enrolling at a community college costs, you can complete them at your own pace alongside work, and they’ll satisfy the recency requirement at every CODA program. The full four-course biology stack (BIO 135 + BIO 270 + BIO 275 + BIO 210) runs roughly $2,800–$3,000 — versus $4,500–$6,000 in tuition at most in-state community colleges, and significantly more at out-of-state institutions. |
Every CODA-accredited dental hygiene program requires lab components for its biology prerequisites. This isn’t optional, and it’s not a checkbox — admissions committees specifically look for the word “with lab” or a separate lab credit on your transcript before they’ll count a biology course toward your prerequisites.
The lab requirement exists because dental hygiene is fundamentally a clinical, hands-on profession. Programs need to know that you can follow protocols, work safely in a lab environment, and translate textbook concepts into physical procedures. A biology course without a lab — even a high-quality, rigorous lecture course — doesn’t demonstrate any of those skills.
The good news for online learners: the lab requirement does not mean you have to physically attend an in-person lab. Virtual lab platforms like Labster, McGraw-Hill Connect Virtual Labs, and HHMI BioInteractive simulations have become widely accepted by CODA programs over the past decade, especially since the pandemic-era policies of 2020–2022 that explicitly approved online lab coursework. The PrereqCourses biology sequence uses these accepted virtual lab platforms, and the lab credit appears explicitly on the transcript issued by Upper Iowa University.
If you’re considering a biology course from any provider, the single most important question to ask is: “Does the lab credit appear separately on the transcript?” If the answer is no — if the course is listed as a 3-credit lecture without lab — most CODA programs will not accept it as fulfilling the biology prerequisite.
The institution where you take your biology prerequisites matters as much as the courses themselves. Almost every CODA-accredited dental hygiene program requires prerequisite coursework to come from a regionally accredited U.S. college or university. Nationally accredited institutions, vocational programs, and unaccredited online providers will not satisfy the requirement, even if the course content is identical.
The seven regional accreditors recognized by the U.S. Department of Education are:
Coursework from any institution accredited by one of these seven bodies will be accepted at virtually every CODA-accredited dental hygiene program in the country. PrereqCourses.com courses are issued through Upper Iowa University, which is accredited by the Higher Learning Commission — meaning the credits transfer cleanly to dental hygiene programs nationwide.
Dental hygiene admissions are competitive — at most CODA-accredited programs, only 25–40% of qualified applicants are admitted. Biology grades are the single most important factor in determining who makes the cut among qualified applicants.
The reason: every program calculates a separate prerequisite GPA — typically a science-only GPA or a prerequisite-courses-only GPA — and uses that number, not the cumulative GPA, as the primary admissions metric. A 3.8 cumulative GPA with a 2.9 prerequisite GPA looks worse to admissions than a 3.4 cumulative with a 3.7 prerequisite. The biology stack accounts for the majority of the prerequisite GPA, so biology grades disproportionately affect admissions outcomes.
Target grades by competitiveness tier
| Program tier | Biology GPA target | What this looks like |
|---|---|---|
| Highly competitive (UMD, Pacific, USC) | 3.7+ | Mostly A’s, possibly one B in the toughest course |
| Competitive (most public-university programs) | 3.3–3.7 | Mix of A’s and B’s, no C’s in core courses |
| Standard (most community college programs) | 3.0–3.3 | Mostly B’s with possibly a C in one course |
| Minimum to apply (most programs) | 2.5–2.75 | Floor for application; rarely admitted at this level |
The implication: if you earned a C in A&P I five years ago, retaking it for a higher grade (when allowed by your target programs) can do more to improve your admissions chances than almost any other application improvement. Many dental hygiene programs allow grade replacement for retaken prerequisites; others average the original and retake grades. Check each target program’s policy before assuming retaking will help.
Pathway 1: Community college (in-person)
Cost: $4,500–$6,000 in-state, $9,000–$15,000 out-of-state. Timeline: 18–24 months for the full sequence (one course per semester, sequential prerequisites). Pros: in-person labs, established academic infrastructure, often subsidized by state residency. Cons: rigid scheduling makes it nearly impossible to work full-time; out-of-state students pay 2–3x the in-state rate; campus-based labs require physical attendance.
Pathway 2: Four-year university extension (online or hybrid)
Cost: $6,000–$12,000 for the full biology sequence. Timeline: 12–18 months. Pros: regional accreditation, recognized brand names, often hybrid online/in-person options. Cons: significantly more expensive than community colleges; many require formal admission to the institution before allowing prerequisite enrollment; pacing is fixed by the academic calendar.
Pathway 3: Dedicated online prerequisite providers
Cost: $2,800–$3,200 for the full four-course biology sequence. Timeline: 3–12 months depending on pacing. Pros: lowest cost option, fully self-paced, designed specifically for prerequisite completion, regional accreditation through partner universities. Cons: requires self-discipline; not all providers are regionally accredited (verify before enrolling); fewer in-person community supports.
PrereqCourses.com falls into the third category. The complete biology stack — General Biology, A&P I, A&P II, and Microbiology with labs — is delivered fully online, self-paced, with regional accreditation through Upper Iowa University. Total cost runs roughly $2,800–$3,000, which is less than half of what community college tuition runs in most states, and is accepted at every CODA-accredited dental hygiene program that accepts regionally accredited prerequisite coursework.
Use this checklist to verify that your biology prerequisites are on track before submitting your dental hygiene application:
| Pre-application biology checklist☐ All four biology courses completed: General Biology, A&P I, A&P II, Microbiology☐ Each course includes a lab component (visible on the transcript)☐ All courses completed at a regionally accredited U.S. institution☐ All courses completed within the recency window of every program you’re applying to☐ Minimum grade earned in every biology course (typically C or higher; B+ for competitive programs)☐ Total biology credit count on transcript: 12–16 credits (or whatever each target program requires)☐ Official transcripts requested and sent through the appropriate application service (ADEA DHCAS for most programs)☐ Prerequisite GPA calculated and confirmed at or above each target program’s minimum |
Can I substitute one biology course for another?
Sometimes. A handful of programs accept genetics, cell biology, or upper-division biology coursework as a substitute for General Biology. Almost no programs accept substitutions for A&P I, A&P II, or Microbiology — those three courses are universally required by name. Always verify substitution policies with each target program before relying on them.
Do I need to take biology at the same institution as my other prerequisites?
No. Most CODA-accredited dental hygiene programs accept prerequisite coursework from any combination of regionally accredited institutions. You can take General Biology at one community college, A&P I at another, A&P II online, and Microbiology through a four-year university extension — and all four will count as long as each individual institution is regionally accredited.
How long does it take to complete the full biology prerequisite stack?
With sequential coursework at a community college, the full four-course biology stack typically takes 4 semesters (18–24 months) because A&P I is a prerequisite for A&P II, and General Biology is sometimes a prerequisite for A&P I. With a self-paced online provider like PrereqCourses, motivated students complete the full stack in 6–9 months by working through courses sequentially without waiting for semester boundaries.
Can AP Biology credit count toward my biology prerequisite?
It depends entirely on the program. Some CODA programs accept AP Biology credit if it appears on a college transcript and meets the credit-hour requirement. Many programs explicitly require college-level biology coursework regardless of AP scores. Almost no programs accept AP Biology credit as a substitute for A&P or Microbiology — only for General Biology, and even then only at programs that accept AP credit.
What happens if my biology course is older than the recency window?
You retake it. There’s no appeal process for the recency rule at most CODA programs. The good news: retaking biology prerequisites through an online provider is fast (3 months per course at full pace) and cheap (under $700 per course at PrereqCourses), and the new transcript completely resets the clock. A career changer with 15-year-old biology coursework can rebuild the entire 16-credit biology stack in under a year for less than $3,000.
Are online biology courses with virtual labs accepted by CODA programs?
Yes, at virtually every program — provided the institution issuing the credit is regionally accredited and the lab credit appears on the transcript. Online biology with virtual labs has been widely accepted since the 2020–2022 pandemic-era policy changes that explicitly approved online lab coursework. Verify each target program’s current policy, but the answer is overwhelmingly yes.
If you’re starting from zero — career changer, returning student, or first-time college applicant — you need 12–16 biology credits across four specific courses, all with labs, all from a regionally accredited institution, all within the recency window required by your target dental hygiene programs. That’s a non-trivial logistical and financial challenge.
PrereqCourses.com solves the entire problem with one provider:
All four courses are issued through Upper Iowa University, a regionally accredited institution accredited by the Higher Learning Commission. The complete 16-credit biology stack costs roughly $2,800–$3,000 — less than half of community college tuition in most states and a small fraction of out-of-state or four-year university extension pricing. The courses are fully online, fully self-paced, and accepted by CODA-accredited dental hygiene programs across the country that accept regionally accredited prerequisite coursework.
The biology prerequisite stack is the largest single requirement for dental hygiene admission — and the one most likely to determine whether your application succeeds or stalls. Building it cleanly, with the right courses, the right labs, the right grades, and the right institution, is the most important early-stage decision you can make as a future dental hygienist.
Visit PrereqCourses.com to enroll in the dental hygiene biology prerequisite sequence today.
