For years the working assumption in dentistry was simple: sign an approved associate agreement, work to its terms, and you were self-employed for tax. That assumption no longer holds. A signed agreement, however well drafted, is now only the starting point. Whether an associate is genuinely self-employed, caught by the employment-status tests, or working inside the off-payroll rules through a limited company depends on the substance of the arrangement, not the document alone.
This guide focuses on the agreement and the status question that sits on top of it. It explains what changed in April 2023, the clauses that genuinely carry weight, when the off-payroll (IR35) rules apply to a limited-company associate, and what is at stake if HMRC decides the relationship is really employment.
The April 2023 change: the agreement no longer guarantees self-employment
HMRC used to operate a special arrangement, set out in its Employment Status Manual at ESM4030, under which an associate dentist working to a standard British Dental Association or Dental Practitioners Association agreement was accepted as self-employed, with earnings taxed as trading income, provided both parties stuck to the contract terms.
That concession was withdrawn with effect from 6 April 2023. ESM4030 now simply directs readers to the general employment-status guidance and to HMRC's Check Employment Status for Tax (CEST) tool. In plain terms, there is no longer any automatic self-employed status for associates. Status is determined on ordinary first principles, the same case-law tests applied to any other worker, by reference to the agreement and to how the associate actually works day to day.
This is the single most important point for any associate or principal to absorb. Older guidance and many practice handbooks still imply that the agreement itself secures the position. It does not. HMRC has indicated it does not intend to backdate any change of view to before 6 April 2023 where the practice and associate were correctly following the old ESM4030 approach, but from that date forward everyone is on the general rules.
The good news is that the dental model still naturally supports self-employment for most associates. Clinical autonomy, your own indemnity cover, your own loupes and handpieces, and fee-split or per-UDA payment all point towards genuine self-employment. The point is that this now has to be demonstrated through the facts, not assumed from the paperwork.
The status factors HMRC weighs
There is no single statutory definition of self-employment. Status rests on a body of case law, applied by HMRC through CEST and the Employment Status Manual. No one factor is decisive; HMRC stands back and looks at the overall picture. The table below sets out the main factors and how each tends to present in a dental setting.
| Factor | Points towards self-employment | Points towards employment |
|---|---|---|
| Personal service and substitution | A genuine, exercisable right to send a suitably qualified locum to cover the work | The associate must personally do the work; cover is just holiday arrangement by the practice |
| Control | The associate decides clinical approach, treatment planning and how patients are managed | The practice dictates hours, sessions, methods and protocols beyond regulatory necessity |
| Mutuality of obligation | No obligation on the practice to provide work or on the associate to accept it | Guaranteed sessions, set rotas and an expectation that offered work is taken |
| Financial risk | Income varies with work done; bad debts, lab bills and remakes can fall on the associate | Fixed or guaranteed income with no real exposure to loss |
| Provision of equipment | The associate funds their own indemnity, loupes, instruments and CPD | The associate simply uses practice-supplied facilities and materials |
| Integration | The associate operates as a distinct business, not part of the practice's staffing structure | The associate attends staff meetings, follows internal systems and looks like an employee |
A right of substitution that exists only on paper carries little weight. Equally, some practice control is unavoidable in dentistry because of regulatory, indemnity and patient-safety requirements. The question HMRC asks is whether the control goes beyond what professional compliance genuinely requires. Mutuality of obligation, the give-and-take of guaranteed work for guaranteed attendance, is one of the strongest pointers towards employment and is worth examining closely in any associate arrangement.
Which clauses in the agreement actually matter
Because status now turns on substance, the agreement earns its keep only where its clauses describe, and the parties then deliver, a genuinely self-employed relationship. A few clauses do real work:
- Substitution. A clause permitting the associate to provide a suitably qualified substitute at their own cost is valuable, but only if it is genuine and capable of being used in practice. A clause hedged so heavily that substitution could never actually happen adds nothing.
- Control and clinical autonomy. Wording that leaves clinical judgement and treatment planning to the associate, and limits practice direction to regulatory and quality matters, supports self-employment, provided the practice does not in fact micromanage the work.
- No mutuality of obligation. The absence of any guarantee of work, and of any obligation to accept it, is a strong self-employment pointer. Guaranteed minimum sessions pull the other way.
- Financial risk. Fee-split or per-UDA payment, with the associate bearing lab fees, remakes and bad debt on private work, evidences genuine risk. A fixed retainer or fully guaranteed income undermines it.
- Own costs and indemnity. Confirming that the associate funds their own indemnity, equipment and CPD reinforces that they run a business rather than fill a staff role.
None of this works if the day-to-day reality contradicts the document. HMRC and the tribunals look through the wording to what the parties actually do. A polished agreement sitting on top of an employee-like working pattern is a liability, not a shield, because it shows the parties understood the right test and then failed it.
When the off-payroll (IR35) rules bite
The status discussion above applies where an associate contracts directly as an individual. A separate layer of rules, the off-payroll working rules, applies where the associate works through their own limited company, often called a personal service company or PSC.
Whether IR35 produces an extra obligation, and on whom, depends on the size of the engaging practice:
- Medium or large engager: the off-payroll rules in Chapter 10 of Part 2 ITEPA 2003 apply. The end client, the practice, must decide the associate's status, issue a Status Determination Statement setting out the decision and the reasons, and take reasonable care in reaching it. If the role is inside IR35, the fee-payer operates PAYE and National Insurance before paying the company, so the company receives net amounts and the usual salary-plus-dividend extraction is not available on that income.
- Small engager: the off-payroll rules do not apply. Instead the older intermediaries legislation (Chapter 8 ITEPA 2003) leaves the PSC itself responsible for assessing its status and accounting for any liability.
Whether a practice is small turns on the Companies Act size tests, broadly two of three thresholds for turnover, balance-sheet total and employee numbers. Most single-site practices are small, so their associates' companies remain responsible for their own status. Many dental groups, however, exceed the thresholds and become medium or large, which shifts the decision and the PAYE obligation onto the group. It is worth verifying the engager's size rather than assuming, because the answer changes who carries the risk.
A locum or associate operating across several practices can hold a mixture of determinations: outside IR35 with a small single practice, inside IR35 with a large group, all in the same tax year. There is nothing inconsistent in that; each engagement is assessed on its own facts.
What is at stake if HMRC reclassifies
The cost of getting status wrong is real and usually lands on the engager. If HMRC decides a supposedly self-employed associate was in substance an employee, or that an inside-IR35 PSC engagement was wrongly treated as outside, the practice can face:
- back PAYE income tax on past payments;
- employer and employee National Insurance contributions for the periods in question;
- interest on the underpaid amounts; and
- penalties, the level of which depends on whether HMRC regards the error as careless or deliberate, and on whether reasonable care was taken.
Because this exposure sits primarily with the practice rather than the individual, principals have a strong incentive to make sure associate arrangements are genuinely self-employed in substance and properly documented. Associates have their own reasons to care: a reclassification can disrupt years of tax planning and, for a limited-company associate, can strip the expected efficiency out of past income.
Practical protection for both sides
The sensible response to the post-2023 landscape is to align the agreement with reality and keep evidence that the relationship is what it claims to be. That means reviewing how the associate actually works, not just rereading the contract; using CEST as a sense-check while remembering it is only as good as the answers fed into it; and keeping records that show genuine autonomy, real financial risk and the absence of an employee-style obligation.
For a limited-company associate, confirm the engager's size each year, obtain and retain any Status Determination Statement, and understand the 45-day client-led process for challenging a determination you think is wrong. For a practice, take reasonable care over every determination and document the reasoning behind it.
Status sits alongside the wider picture for associates, so it is worth reading this in tandem with our overview of associate dentist tax, our explainer on whether a BDA model agreement guarantees self-employed status, the broader comparison of associate versus self-employed status, and our note on when HMRC may challenge associate self-employment.
The headline has not really changed for the well-run, genuinely independent associate: most still qualify as self-employed because the dental model supports it. What has changed is that you now have to be able to show it. The agreement is your evidence, not your guarantee, and it only protects you if the way you work matches the way it reads.
If you are negotiating a new associate agreement, reviewing an existing one, or weighing up working through a limited company, take advice on your specific facts before HMRC, or a buyer's due-diligence team, raises the question for you.