Legal Cases: Mandibular implant placement with resulting paresthesia

2014 03 14 15 01 02 730 Law Books 200 is pleased to present the next column from two lawyers who spend every day defending dentists in litigation and before the licensing board. The purpose of this column is to offer our readers a fresh perspective on common practice and risk management issues from attorneys who litigate these issues in the real world.

The client is this case was a general dentist who focused a good portion of his practice on implant placement and restoration. A 49-year-old patient had no complaints other than that she was missing her lower right first molar, #30, and wished to restore the area. After an examination and full-mouth series of x-rays, a treatment plan was established that called for the placement of a single implant at the edentulous site, followed by a crown.

On the best periapical x-ray of the intended surgical site, our client measured 10 mm of available bone superior to the radiographic location of the inferior alveolar canal, so the dentist planned to place an 8-mm implant.

William S. Spiegel

The patient signed a surgical consent form that listed the usual risks, including that of "altered sensation, which could be temporary or, rarely, permanent"; the patient's signature was witnessed by a dental assistant.

On the day of surgery, the dentist gave an uneventful mandibular block and local infiltration. Once the patient was numb, a soft-tissue flap was elevated and the sequential drilling began. As the dentist reached the target depth, he felt a slight decrease in resistance at the final 1mm or so, but the patient did not react unusually. The dentist attributed the oozing he saw in the osteotomy site to be expected bone bleeding.

The site was irrigated thoroughly, and most of the bleeding stopped. A titanium implant was ratcheted into position with appropriate external irrigation. The site was sutured, the patient was given postoperative instructions with an appointment to return in a week -- or sooner if there was a need -- and prescriptions for antibiotics and pain medications were provided.

The following morning, the patient called the office, complaining that she was still numb on her right lip and chin. The receptionist, without checking with the dentist, told the patient that this was to be expected and that the dentist would check it next week when the patient returned for suture removal.

“The receptionist, without checking with the dentist, told the patient that this was to be expected and that the dentist would check it next week.”

At that suture removal visit, the dentist first learned of the altered sensation over the course of the right inferior alveolar nerve (IAN). He kept the implant in place, and he made no referrals, but told the patient that he would continue to monitor the condition over time.

The patient came back virtually monthly for a year; at each visit, the dentist documented the paresthesia, noted its location, which remained essentially unchanged, but never sent her to any specialist. The dentist decided to wait to restore the implant until feeling returned, which began to upset the patient, so she went to another dentist who immediately referred her to an oral surgeon.

By then, it was 15 months since the surgery. The oral surgeon, who took 3D imaging studies, told the patient that the tip of the implant was sitting within the nerve canal, fully integrated, so it could not be removed without bony surgery. The oral surgeon also told the patient that the time window for nerve repair had closed.

Legal stance

The patient filed suit, claiming departures from the standard of care:

  • In failing to obtain adequate presurgical x-ray and/or other imaging studies
  • In placing an implant of excessive length
  • In failing to remove the implant upon the patient's complaint of paresthesia
  • In failing to timely refer the patient to a proper specialist

The patient also claimed a lack of informed consent. She claimed that she will be numb forever, which negatively impacts her ability to eat, affects her personal life with her husband, and causes her to drool in public whenever she drinks liquid.

Issues raised

  • X-rays: The plaintiff argued that periapical x-rays are subject to elongation and foreshortening, thereby providing a potentially inaccurate basis for measuring the amount of bone superior to the canal, which the plaintiff's attorney called the "safe zone." She claimed that the standard of care in posterior mandibular implant cases calls for 3D imaging studies so as to eliminate the inaccuracies inherent with periapical x-rays and provide the dentist with a more exact assessment of bone available without nerve impingement. The postplacement studies taken by the oral surgeon demonstrated a full 3 mm difference from the pre-op periapicals.

  • Postplacement follow-up with possible referral: When the patient complained of paresthesia on her suture removal visit, the dentist was put on notice of some sort of injury to the IAN, whether temporary or more long-standing. Consideration should have been given, at least in potential concept, to removal of the implant, at that visit or shortly after, if the alteration in sensation did not resolve. By telling the patient to continually follow-up with him, as compared with early referral to a specialist such as an oral surgeon, meant that a compliant patient -- as this one was -- would be left untreated for her nerve injury until the implant had fully integrated and the window of opportunity for nerve repair had passed.

  • Communication within the office: The dentist's receptionist inappropriately took it on herself to instruct the patient that her complaint need not have been taken seriously and compounded that by failing to advise the dentist of what the patient had called about.


Before trial, we moved to dismiss the claim of lack of informed consent. We argued that the patient, who was an educated adult, should be held to having signed the consent form, especially when it contained language, just over her signature, that stated that she had fully read and understood the contents; that she had had the opportunity to discuss with the dentist all of the issues in the form; that she had all of her questions answered; and that she agreed to have the procedure done, with knowledge of the potential risks associated with it. The court agreed and dismissed only this portion of the claim.

This case was settled during jury selection for a confidential but very reasonable amount. The decision to settle in light of the presence of a strong signed consent form was influenced by many factors, including the venue, client versus patient jury appeal -- not to mention some of the issues noted above.

Practice tips

  • X-rays: While we do not comment upon or suggest the specific types of diagnostic studies that should be performed, we do advocate that, before undertaking implant placement, the dentist must have full awareness of anatomic structures (nerves, blood vessels, sinus cavities, etc.) that may be in the area, so as to be able to avoid them. Decisions as to how to work with or around anatomy is left to the dentist, but taking or ordering x-rays and/or other diagnostics to locate what is present is critical.

  • Informed consent: As we have previously commented, a written consent form is only part of the informed consent process. It is certainly valuable for patient education and liability protection, but a signed consent form is not a replacement for a solid back-and-forth discussion between dentist and patient. Jurors prefer to see a written consent signed by the patient, but we must not lose sight of the goal, which is clear communication of some form between the doctor and patient.

  • Office staff: The dentist must not permit receptionists or dental assistants to give out dental or medical advice. Staff members need to be told that they should listen to what patients have to say regarding dental issues, problems, or complaints, tell the patient that the information will be given to the dentist and that the office will get back to them shortly, but not give out advice. It is arguably illegal, but practically speaking, it is an area of danger for the patient's health and the dentist's liability.

  • Referrals: Regardless of what area of dentistry is involved, there are likely other practitioners with more specific knowledge or experience when problems arise. If you choose to stay with a patient problem, make sure that you are fully familiar with the area at issue and that you understand all the foreseeable effects. If not, referral -- with documentation -- is the best way to protect the patient and the dentist.

Next case: Antibiotic-associated colitis leading to death

William S. Spiegel, Esq., is a partner at the law firm Spiegel Leffler in New York City. He is a former assistant corporation counsel to the City of New York -- Medical Malpractice Division.

Marc R. Leffler, DDS, Esq., is also a partner at Spiegel Leffler. He received his dental degree from Columbia University, completed a residency in oral and maxillofacial surgery at New York University, and is a diplomate of the American Board of Oral and Maxillofacial Surgery.

Disclaimer: Nothing contained in this column is intended as legal advice. Our practice is focused in the state of New York, and there are variations in rules of practice, evidence, and procedure among the states. This column scratches the surface on many legal issues that could call for a chapter unto themselves.

The comments and observations expressed herein do not necessarily reflect the opinions of, nor should they be construed as an endorsement or admonishment of any particular idea, vendor, or organization.

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