“Help! I placed a dental implant too close to the IA nerve!”
This is not an uncommon thought for a dentist placing dental implants in the posterior mandible. Sometimes, it is not clear on the panoramic image exactly where the Inferior Alveolar nerve is. Other times the patient may jump up in the chair when you are only a couple of millimeters deep.
It is a commonly accepted best practice to maintain a distance of at least 2mm away from the IA nerve when placing implants. But what if:
- You re-evaluate the radiographs later and begin to wonder if you are too close to the nerve
- Your patient calls you and says they’re feeling pain in that area
- Your patient says their lip is numb even though you have only provided local anesthetic infiltrations
It makes you think twice and maybe loose some sleep over it. Here’s a protocol by Jacobs (2000) you can follow to give you a systematic approach to solving these issues.
If you suspect nerve damage [or pretty much for all cases] call the patient after 6 hours to see how they are doing. Check if they’re experiencing any symptoms of nerve damage. Soreness and some pain is obviously normal, but if they felt burning or persistent numbness — consider taking a post operative CBCT.
Evaluate the CBCT and determine if it is indeed encroaching on the nerve (closer than 2mm). If so, within 36 hours, back the implant away from the nerve to re-establish your safety distance of 2mm.
This 36 hour hour window appears to be important because backing an implant out after this timeframe does not appear to help and may even complicate matters.
If the implant has been encroaching the IA nerve space for over 36 hours, it is possible that some permanent nerve damage has occurred. To manage symptoms of pain in this situation, Jacobs recommends topical anesthetic mouthwash (15% benzocaine/1.7% amethocaine) followed by topical capsaicin treatment twice daily for a 4 week period.
In the posterior mandible, whenever there is any doubt at all I am using a CBCT to get some exact measurements. If you are having a difficult time monitoring the depth of your drills, you may want to invest in some drill stoppers (Salvin offers a Universal Drill Stop).
Hope this helps.