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Avoiding & Managing Dental Implant Complications: Paresthesia

Etiology and Avoidance

Nerve injuries occurring during implant surgery can be from multiple causes. Mandibular block anesthesia and infiltration, especially in the area surrounding the mental foramen, can cause an altered sensation involving the lip, chin, and the tongue. Retraction injuries can also present with similar symptoms. In the majority of these cases the resultant paresthesia will eventually resolve.

Nerve injury may also inadvertently occur during osteotomy preparation, especially when the surgeon does not realize that the system drills are longer than the planned implant. As a general rule, a safe zone of 3mm should be respected, in terms of distance from the inferior alveolar nerve and the apical extent of the osteotomy preparation. Increased distances may be indicated when the cancellous marrow is sparse and poor bone density is encountered.

A cone beam CT scan enables the surgeon to avoid or reduce nerve injuries by precisely locating the nerve position at the implant site. It also enables the surgeon to estimate the density of the cancellous marrow.


Initial management of nerve injuries during dental implant surgery is largely dependant on identifying the etiology of the injury and the resultant patient symptomotology.

  • A neurosensory examination should always be performed to document the initial extent and distribution of the resultant anesthesia, paresthesia, or dysesthesia. A cone beam CT scan will aid in the diagnosis and provide accurate information that will allow improved decision making.
  • If the nerve is known to be severed during surgery, then microsurgical exploration and repair is usually indicated.
  • If the injury is caused by impingement of the nerve by a deeply placed implant, backing out or removing the implant may be indicated.

If the patient regains normal sensation postoperatively and then experiences a delayed onset of altered nerve sensation, the surgeon must first rule out a fracture of the mandible. Having done so, an assumption can be made that marrow space edema or hematoma, or infection has caused nerve compression. The treatment in these cases is to prescribe a course of antibiotics and anti-inflammatory medications such as prednisolone. The patient should then be closely monitored with repeated neurosensory examinations at regular intervals.

NOTE: In addition to devoting a full day to the topic of Avoiding and Managing Complications at ISTM 2013 (the Sclar Center’s annual comprehensive dental implant surgery training conference on Miami Beach — February 1-5, 2013), we will offer a 1-day seminar on Avoiding and Managing Dental Implant Complications in Charlotte, NC (November 2, 2012), Orlando, FL (May 10, 2013), and the New York City area (August 23, 2013). See our news release about this seminar.


  1. July 17, 2012

    Dr Sclar, excellent information! Do you believe most of these complications can be avoided with proper and thorough planning of each and every case? I hear all the time from younger or inexperience clinicians that they only tackle the ‘slam dunks’ and leave the difficult cases to us the specialists. I believe that cases that may seem simple are sometimes some of the more difficult and can have a bad outcome such as parethesia. Thanks for the info. Paul J. Denemark, DDS, MSD, Board Certified Periodontist, Burr Ridge, Illinois.

  2. July 17, 2012

    Dr. Sclar,

    Do your recommend cone bean CT scans to be routine for most if not all implant therapy procedures?

    Charles L. Ross, Jr., DDS, MS, MBA
    Miami, FL

    • July 23, 2012

      Charles, you are correct that we recommend a diagnostic Cone Beam CT dental scan for the majority, but not all, of the patients that we see for implant consultation in our practice as the majority of these patients present with advanced and complex case scenarios. I would estimate that 65% of the patients require a 3D anatomical evaluation for implant planning due to complex anatomy related to vital structures or for pre-surgical evaluation when alveolar ridge or sinus lift bone grafting is indicated. Of the remaining 35%, standard dental radiographs are all that are required as they may have presented to our office with a very straight forward case with little risk for damage to vital structures or they may have already had a scan performed by their dentist or another dental specialist. Many of these cases are previous patients who present for implant consultation for a new site due to impending loss of another tooth. When these patients already have a scan on file, we are able to use this scan to evaluate the anatomy at the site in question, thereby avoiding the need for a follow up scan. All of the scans taken in our practice are sent to a maxillofacial radiologist for a comprehensive evaluation and report. I will be writing more on my blog about Cone Beam CT technology soon.

  3. July 18, 2012

    Hello Anthony,

    Great information and good to have someone like you writing about this important topic! Keep delvering such important information.

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