INSIGHTS: The dentist as an independent expert witness

August 4, 2014

When a patient sues a dentist alleging negligence it is the role of the court to weigh up the evidence and then make a determination – unless the parties resolve the dispute otherwise. This involves making findings of fact (e.g. the dentist did not perform an x-ray before proceeding with treatment) and then applying the law to those findings (e.g. the failure to perform the x-ray was a breach of the duty of care the dentist owed to the patient).

The evidence of an independent expert witness can assist the court to reach a conclusion about a technical matter or area of specialised knowledge that is relevant to an issue to be determined in the court case (e.g. the importance of an x-ray as a diagnostic tool and in what circumstances pre-treatment x-rays should be performed).

Experts therefore have an important role in the court process. This role is governed by the law in a number of ways, most notably through the application of an “Expert witness code of conduct”, which forms part of the Uniform Civil Procedure Rule 2005 (NSW). This code applies to any expert witness engaged to provide a report for use in actual or proposed court proceedings.

What is an expert witness?

An expert witness is a person who has specialised knowledge based on the person’s training, study or experience and who gives evidence of an opinion based wholly or substantially on that knowledge.

General duty to the court

An expert witness:

  • has an overriding duty to assist the court impartially on matters relevant to his or her area of expertise (this means being honest and objective);
  • owes a paramount duty to the court and not to any party to the proceedings; and
  • is not an advocate for any party.

In short, an expert witness needs to be truly independent. An expert should not allow his or her opinion to be influenced by who is paying their fee. If you are approached to be an expert it is important that you ask whether any matter compromises your ability to meet this general duty to the court.

Matters to consider include:

  • do you have (or have you had or do you propose to have) any type of relationship with the patient or dentist that would compromise your ability to be impartial? Or to use a sporting analogy, are you capable of “playing with a straight bat”?
  • are you being asked to comment on matters outside your area of expertise?
  • do you feel so strongly about the matter that you want to be an advocate for the dentist or patient as opposed to an impartial expert?

Content of an expert report

An expert report must include the following:

  • the expert’s qualifications as an expert on the issue the subject of the report;
  • the facts and assumptions of fact on which the opinions in the report are based (the letter of instruction from the solicitor retaining the expert can be attached);
  • the expert’s reasons for each opinion expressed;
  • if applicable, that a particular issue falls outside the expert’s field of expertise;
  • any literature or other materials used in support of the opinions;
  • any examinations, tests or other investigations on which the expert has relied, including details of the qualifications of the person who carried them out;
  • in the case of a report that is lengthy or complex, a brief summary of the report (to be located at the beginning of the report);
  • an acknowledgement that the expert has read the expert witness code of conduct and agrees to be bound by it.

If an expert witness who prepares a report believes that it may be incomplete or inaccurate without some qualification, the qualification must be stated in the report.

If an expert witness considers that his or her opinion is not a concluded opinion because of insufficient research or data or for any other reason, this must be stated in the report.

Importantly, if an expert witness changes his or her opinion on a material matter after providing a report, the expert witness must immediately provide a supplementary report to that effect (this should be provided to the solicitor who retained the expert).

An expert will be paid a reasonable fee for his or her report. This is a matter to discuss and agree upon with the solicitor instructing the expert.

The importance of language

As the role of the expert is to assist the court, it is important for the expert to prepare a report that adequately explains technical issues. For example, the following matters will assist the court to understand the expert’s opinion:

  • an explanation of the tooth numbering system;
  • an explanation of the relevant anatomy (e.g. maxillary sinus or inferior alveolar nerve etc.);
  • a simple explanation of terms such as edentulous, distal, mesial, buccal, lingual, periapical, osseointegration etc.

The incorporation of diagrams, images and tables to explain these matters is most helpful.

The importance of reasoning

An expert’s opinion is a reasoned conclusion drawn from specialised knowledge based on facts which the expert has observed, assumed, or been instructed to assume.

When a court is weighing up differing expert opinions, it is the well reasoned opinion that will be given more weight. For example (and with reference to the simple example of the performance of a pre-treatment x-ray), if asked whether a dentist should have performed a pre-treatment x-ray, it is not sufficient to simply answer with a “yes” or “no”. The expert must explain, in a manner that would be understood by a non-dentist, why an x-ray should have been performed to meet a reasonable standard of care or conversely, why the decision not to perform an x-ray was acceptable in the circumstances.


If you are retained as an expert you must remember to keep the material you receive confidential. Do not disclose the material to a third party unless you obtain approval from the solicitor instructing you. If you are approached to produce the material, some of it may be privileged and again, you should contact the solicitor for guidance. At the end of the case the material should be returned to the instructing solicitor or disposed of securely by agreement.

Role in court

If you take on the role of an expert witness you must be prepared to attend court when the case is heard. An expert needs to be prepared to be cross examined by a barrister about his or her opinion. An expert will be paid reasonable expenses for attending court.

Duty to work co-operatively with other expert witnesses

Sometimes a court will order expert witnesses to confer to prepare a joint report in relation to an issue. If an expert is directed by the court to confer in this way then he or she must:

  • exercise his or her independent, professional judgment in relation to the issue;
  • endeavour to reach agreement with any other expert witness on that issue; and
  • not act on any instruction or request to withhold or avoid agreement with any other expert witness.

Be an expert dentist, not a bush lawyer

It is important for the expert to understand that it is not his or her role to:

  • offer opinion on matters outside his or her specialised knowledge (e.g. do not offer opinion as to whether a patient has a psychiatric condition if you do not have the expertise to do so);
  • speak to witnesses involved in the case to gain a better understanding of the facts (an expert should always approach the retaining solicitor for further information if required);
  • offer opinion on legal matters (e.g. it is not the role of an expert to say whether a dentist has been negligent or not; that is the role of the court);
  • advance legal argument; that is the role of the solicitor.


  • An expert has an overriding duty to assist the court impartially on matters relevant to his or her area of expertise and is not an advocate for the patient or the dentist.
  • Experts should prepare well reasoned reports that comply with the expert witness code of conduct.
  • Experts should be prepared to attend court to be cross-examined about their opinion.
  • Experts are paid a reasonable fee for preparing an expert report and attending court.

Please contact Principal Marianne Nicolle for more information.

This article was published in The NSW Dentist magazine, August 2014, pp. 12-13.