Possibility to impinge on the mandibular incisive nerve: recommendations?

I have treatment planned a patient for installation of 4 implants in the mandibular anterior area to retain an overdenture.  After examining the CBCT scan I noted that one of the implants would be very close to or impinge on the incisive branch of the inferior alveolar nerve.  If I contact the nerve with the implant what possible complications could occur?  What do you recommend I do to avoid any problems?

15 thoughts on “Possibility to impinge on the mandibular incisive nerve: recommendations?

  1. Use a shorter implant based on the scan measurements or change a location of planned implant to stay away from the nerve

  2. the patient is edentulous (overdenture), that means impinging on the MIC (mandibular incisive nerve) won’t cause complications, doesn’t it?. MIC supplying the incisors, canines and premolar. so if these teeth were not there, would be there any problems!!

    • I agree with you, the mental nerve is the main concern, not sure if the poster is indentifying a nerve, marrow space or blood vessel without seeing the CT.

  3. This is a recurring question on this forum. Now that most clinicians are using CBCT scans, the true complexity of anatomy in the anterior mandible is evident. I have copied a portion of one of my responses from two years ago: “If you transect this structure when teeth are still present, you will devascularize the teeth anterior to the resected segment. If, however, the ridge is totally edentulous, there is less concern. The real considerations are: 1. What is the density of bone anteriorly? If it is D1, elimination of the blood supply raises the chance of pathologic fracture. Larger medullary spaces have other collateral blood supply. 2. If you are relatively close to the mental foramen, you run the risk of Wallerian degeneration of the proximal segment of this branch, resulting in dysesthesia, most commonly manifested as a burning sensation. However, you will generally not get a sensory deficit, or parasthesia, as few branches of this anterior nerve supply the lip or chin. The only exception is when there is a branch at the cuspid position called the superior genial nuerovascular bundle. You will get a slight deficit in the chin area but not the lip.”
    RJM

    • It is on my wish list also. But a lot of Dr miller’s comments delve into way too much detail in my opinion. Just staying within the alveolus and avoiding the lingual periosteum will keep you out if trouble, during surgery many small blood vessels and nerves are cut it is knowing which ones to avoid and which ones will regenerate. However based on his comments I did some research on this micro anatomy which was indeed helpful. I use a background in orthognathic surgery and the surgical anatomy as a guide for placing implants. Sometimes my ct scans used with difficult third molars give me more information that I want to know about! But I’m not criticizing cone beams I think they are a useful adjunct when used with scan appliances for orientation. Thanks as always for reading!

  4. Richard; I make it a habit not to use the word never or always when discussing 3 dimensional imaging. This year will be ten years that I have had a CBCT in my practice (NewTom 3G). I find that, with the convenience of having it in ofiice, I have become more dependent than ever on this technology. It has not only given me greater appreciation for the complexity and variability of maxillofacial anatomy, it has also given me a capacity to treatment plan and surgically execute my cases more predictably and more safely. As an expert reviewer for dental malpractice cases (predominately in implant dentistry), I can tell you that plaintiff’s attorneys are well versed in this modality. When they talk about the standard of care today, it is no longer what the majority of clinicians in an area would do, but rather what a prudent clinician would do under the same circumstances. In the cases I review, most, if not all, of these untoward consequences could have been mitigated or prevented if 3 dimensional information had been used. CRS, don’t know what you mean by too much information. The intraforaminal zone has been taught as the “zone of safety”. But an AAOMS survey from several years ago, presented at AO and covering complications of placement of implants in the anterior mandible, indicates that the highest morbidity and even mortality occurs from improper implant placement in this area. Isn’t it incumbent upon us, PRIOR to surgery, to have as much information as possible to prevent doing harm to the patient? In fact, I was so impressed by some of the papers being written discussing mortality of patients following hemorraghic episodes following implant placement in the mandible, we followed up with a paper in the Journal of Oral Implantology (2011) entitled “Maxillofacial Anatomy: The Mandibular Symphysis”. This anatomy should be taught to every entry level student anticipating doing surgery in the anterior mandible. If oral surgeons are going to lambaste a GP for complications of implant surgery, they should be sensitive to anatomical considerations as well.
    RJM

    • Dr Miller, Regarding the mentioned article “Maxillofacial Anatomy: The Mandibular Symphysis”, it was very Helpful, thanx

    • You know I was not lambasting you, it is simply my opinion.I standby my statements stay in the alveolus, know the anatomy and how to control hemorrhage. Don’t understand the defensiveness from an expert reviewer and I actually complemented you on providing the information which I stated was helpful. Love using CT planned cases! And actually I got a lot of this anatomy of the anterior mandible and floor of the mouth in surgical residency so thanks for recognizing that. It is really interesting however to see it on a CT ! I complement you on taking the time to review cases I would not have the patience and I am way too judge mental so thanks for educating me! Thanks for reading!

  5. We fortunately have a scanning company nearby and hence scan any patient where there may be any issues of concern , so end up doing 8 or so a weeks and the patient pay $130 per scan .
    The main benefit of this service is that all scans are assessed by a qualified Maxillo-facial radiologist to check for any pathology etc.
    THis is a very important medico legal aspect as merely buying a machine puts you in more of a compromised position unless you have the skill to analyse the case fully .
    Peter

  6. Peter; Nice to see that you are using a CBCT very often for your cases. It’s also great that you are using a Maxillofacial Radiologist to review those scans. But I have a huge conceptual problem with this paradigm. Where do you think the greatest liability resides; reviewing radiographs or performing oral implantology procedures? As clinicans, we take radiographs daily and review them, ostensibly for pathology. Does a CBCT scan offer diferent interpretations of a PA, FMX, or panorex? If we fail to diagnose using these modalities, we have our share of liability. Quite honestly, a CBCT enhances our ability to find pathology. Greater resolution and multiple planes of view make it virtually impossible for pathology to get by us. If we find an area of concern, it is then that we refer a case to OMFR, OMFS, Oral Pathologist, ENT, Plastics, etc. But to abrogate our responsibity as the gate keepers in dental medicine is a little hard to swallow. Pathology is pathology, regardless of the modality you use.
    RJM

    • Dr Miller makes a good point, it is not always easy. I have had maxillofacial radiologist second opinions which are very helpful but in surgery, the surgeon stands alone. Even with the best imaging problems can occur so the imaging is a great guide, second opinions are good but it is always a judgement call and we are learning every day. Very good discussion thanks for the information.

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