The Negligent Dentist and the Platiff's Burden of Proof
Proving that dental malpractice occurred in the extraction of a third molar can be difficult. In a dental malpractice case, the burden of proof is upon the plaintiff/injured party to prove the dentist was negligent during the extraction of the third molar and that this is the cause of plaintiff's lingual nerve injury. The dentist may also have been negligent in the post-operative care of the patient which has resulted in nerve injury or failure to resolve or minimize same. It is generally easier to prove negligence when it is a general dentist who injures the lingual nerve during a third molar extraction due to the disparity in their training when compared to an oral surgeon. The issues of proof for both the general dentist and the oral surgeon will be influenced by the nature of the injury i.e. anesthesia, paresthesia/dysesthesia. Here are some of the considerations to determine if there is a basis for a claim against a dentist for the negligent extraction of a third molar:
a. Is there a signed written consent form listing the risks of nerve damage;
b. Are there adequate x-ray studies of the third molar before extraction. The radiograph should show complete visualization of the third molar and surrounding anatomical landmarks(see Image below; see also, the page on Cone Beam CT or CBCT below);
Image #6a: Panoramic x-ray of the third molar in relation to the inferior alveolar nerve.
c. Was this a high risk extraction that should have been referred by the general dentist to an oral surgeon. Is the third molar fully erupted, partially erupted or fully impacted. What is the position of the tooth and where is in located in relationship to anatomical landmarks, namely the relationship of the roots to the inferior alveolar nerve canal, or overlapping that canal on radiographs. If there is doubt as to the position of the third molar in relationship to the inferior alveolar canal on standard screening with periapical and panoramic x-rays, then a Cone Beam CT (CBCT) radiographic examination should be requested by the dentist before extraction of the third molar (See Image 6a above and Image 6b below);
Image 6b: Five radiographic signs indicating juxtaposition of the mandibular
canal to the third molar roots, as described by Rood and Shelab 1990. Signs
significantly related to nerve injury are: A. Radiolucency across the roots of the third molar; B. Deviation of the mandibular canal; C. Interruption of the white lines of the canal. Signs considered to be clinically important: D. Deflection of the third molar roots by the canal; E. Narrowing of the third molar root. Please see the excellent article on Inferior Dental (Alveolar) & Lingual Nerve Injuries at the Exodontia.Info website at http://www.exodontia.info/DentalNerveInjuries.html
d. Was improper technique or too much force used, resulting in a fracture of the lingual plate or over retraction of the soft tissue overlapping the lingual plate and instrumentation of the lingual nerve;
e. A written report or notes on the extraction surgery should exist in the patient's dental record, but it is not uncommon that this written record does not reflect all of the difficulties that the dentist encountered during the extraction. The actual length of time that the extraction actually took may be an indicator that the dentist had more difficulty with the extraction than his records reflect. Most oral surgeons can extract a third molar in fifteen (15) minutes
f. Did the dentist properly treat the acute nerve inflammation post-operatively andfollow the healing of the nerve injury or lack thereof with nerve mapping to determine if there is any improvement in the nature and/or distribution of the patient's symptoms (See Image 6c below). Sometimes the territory of numbness or neuropathic pain becomes smaller over time and if it does not; the dentist may be required to make appropriate referrals;
Image 6c: Nerve mapping of an injury to the inferior alveolar nerve
g. Did the general dentist/oral surgeon timely refer the patient to an oral-facial pain specialist to treat the patient's neuropathic pain before the problem became worse? Did the dentist refer the patient to an oral surgeon trained in micro-surgery to timely present the patient with the options of nerve decompression microsurgery (removing a hematoma, scar tissue or anything that impinges on the nerve). See Retrospective Review of Microsurgical Repair of 222 Lingual Nerve Injuries, from the Journal of Oral Maxillofacial Surgery 2010;
h. Does a subsequent Cone Beam CT (CBCT)indirectly confirm the location and nature of the lingual nerve injury. If the CBCT demonstrates that the lingual plate has been violated or if exploratory surgery by a micro-surgeon directly visualizes complete transection of the lingual nerve, many of the defenses for the treating dentist are eliminated; and
i. Is there evidence that the papillae on the tongue surface have atrophied. If so, this isevidence that the papillae are not being innervated (injury to the lingual nerve or the chorda tympani).