Transpositioning inferior alveolar nerve for dental implant placement

Date: 31/05/2018 / Author: Mr Hiếu

Lower abdominal nerve root surgery and dental implant transplant: Clinical report

(Journal of Medical Research, Vol. 1, pp.89-99.) 
Vo Van Nhan DDS.PhD

 The report on congenital implantation is published in international journals

 TS - Dr. Vo Van Nhan participated in the report at the Conference on Science and Training teeth jaw 5th


Inferior alveolar nerve transposition for implant placement was first performed by Jenson and Nock in 1987. It has been a recommended treatment for edentulous patients with atrophic mandible when other methods for bone augmentation cannot be indicated. During inferior alveolar nerve transposition which was based on Jenson’s technique, we also performed vertical ridge augmentation with iliac crest autogenous bone graft and placed 4 implants for a complete overdenture in a 59-year-old patient with atrophic mandible. In addition, we carried out free soft tissue graft and vestibuloplasty to improve soft tissue around the implants and loose connective tissue on alveolar crest. Results: the 4 implants present successful osseointegration, stable prosthesis and good function. No complications were recorded. The paresthesia disappeared after 4 months. The patient could walk normally 4 weeks after harvesting iliac crest bone surgery.

Key word: inferior alveolar nerve transposition, dental implant.

I. Set the problem

One of the most common problems in patients with severe bone loss is bone implantation, particularly in the anatomy of the lower neural tube. In these cases, it is necessary to prepare the implanted bone region with the height from the vertebral topsilateral epithelium to sufficiently secure the implant length (2mm neural tube). The method is to improve the height from the tops of the jaw to the neural tube, such as vertical bone grafting, stretching the bone, regenerating the guide bone, using a short implant and removing the lower jaw nerve. Nerve implantation methods were first performed by Jenson and Nock in 1987 [1]. Then, in 1992, Rosenquist [2] performed on 10 patients (26 implants), with a successful implant rate of 96%. However, the process of neurosurgeon surgery is complex, always accompanied by long-lasting complications such as: lip aneurysm, infection, broken bones (in which lip analysia is a symptom always occurs, is usually temporary, but may not be reversible in some cases.) [3,4] .Muscular and mental health status of the patient, sensitivity, acceptability and co-operation Surgical and therapeutic treatment of patients are also important factors to consider when selecting patients. Characteristics of a high-tech surgery that requires experienced and well-defined surgical technicians, undergoing neuromuscular surgery is not a commonly performed surgery. However, this technique also has some advantages: Implants can be placed at appropriate lengths to ensure the mechanical biopsy of the implant's chewing force thanks to the ratio of crowns and crowns (compared to short implant use to avoid nerve damage); shorten treatment time due to neural displacement, implant placement and bone grafting at the same time; Limit the number of surgeries. This article describes a clinical case of lower alveolar nerve biopsy, combined with bone grafts to increase bone height to place the implant of appropriate length and perform restorative implantation on the implant. Corneal gingival grafting technique, combined with deep coronary angiography, is used to improve tissue around the implant and connective tissues loosely. At the same time, the report also determined the safety of the technique, the degree of complication in neural function and complications in the iliac region for grafted bone.

II. Objects and methods

1. Patient:

- General history: 59-year-old man, good health, no systemic diseases such as diabetes, heart disease ... no drinking habits, smoking.

- Dental history:

Upper teeth: patients with tooth loss from teeth 17 to teeth 21, with removable prosthesis removable plastic parts.

Lower jaw: The left parastatary branch was shot, had a pelvic mass grafted 40 years ago, now the junction is deflected out of the jaw (Figure 2). Loss of teeth from teeth 38 to teeth 47, teeth shaking 48, restoration of less stable and painful to eat chewing. Craniofacial bone grafts are severe, the maxillary jaw is at the level of the mouth and lower than the chin. The upper jaw is very loose, completely free of horny gums.

- X-ray film survey:

Panoramic view: the lower right nerve near the jawline and the lower jaw on the lower jaw outside the jaw.

CT film Cone beam:

The film was taken with a surgical guide trough positioned with contrast material to determine the position of the lower alveolar nerve. The images of the cross sections corresponding to the teeth 47, 46, 45, 44, 43, 42, 41 show the nerve at the jaw-like jaw (Figure 3), at the position corresponding to the 31 teeth At the top of the jaw and just below the mucosa (Figure 4.5). The average distance from the apex to the lower jaw is 10.5 mm and only 7 mm at the position of teeth 33, 34 (Figure 6). Place the implant in the right direction.

Challenge and solution

Challenge: Division of bone graft in jaw 3 is outward, weak and brittle, so implant can not be placed. The entire lower mandibular bone was severely deformed, the median distance from the vertebral topside margin was 10.5 mm, the lowest position was 7 mm, and the distance from the lower mandibular nerve The jaw is only 1-2mm, at the position of teeth 31 junction on the jaw and located just below the mucosa, the mouth floor level horizontal jaw. In addition, loose lining of the gums, no gingival hyperglycemia are the conditions that are not favorable, easily lead to inflammation around the implant later.

With the anatomical, physiological and functional characteristics described, the recommended alternative in this case is the application of the lower abdominal nerve resection technique, bones, implants of appropriate length and prosthetic restoration on the implant, combination of gingival hyperglycemia, increased depth of the coronary corridor to improve loose connective tissue on the jaw and tissue around the implant, Ensure the stability of the soft tissue around the implant, prophylaxis of receding gums and inflammation around the implant. Patients are explained and assessed psychological before proceeding, especially note some risks such as neuropathy, broken jaw bone, bleeding.

2. Methodology:

2.1. Equipment: Use ultrasonic bone machine (Piezotome Satelec, France) to open the neurological window. This is a device that is safe for soft tissue, does not break soft tissue and is quick healing. [4]

2.2. Surgical procedure

Mucosal Route: Patients were given antibiotics and prophylactic corticosteroids (1g cephalexin antibiotic, flagyl 1g). The procedure was performed in patients undergoing anesthesia and local anesthesia with 2% carbocaine containing 1: 100,000 adrenaline.

Surgical procedure: Perform two incision lines on the mucosal lining: one from the position of the tooth 48 to the position of the tooth 41, a line from the position of the tooth 32 to the position of the tooth 35 and 2 longitudinal and perpendicular incisions with two incisors on the jaw (Figure 7). Note that the incisors are not located on the jawbone at the position corresponding to the tooth 31 because the upper jaw is jawed at this position. Perform complete flip-flops including the bone membrane, from the corresponding 48 tooth region towards the proximal to reveal the jaw in the jaw and outer shell, manipulated in the corresponding region of the small molar region carefully performed. To locate the chin hole and reveal the chin nerve. Then, the forward peel to the jaw bone corresponds to the teeth 31, Observe and detach the nerve atrophy from the mucosal lining before cutting the mucosa at the position corresponding to R31 (so as not to damage the nerve). Then continue to dig toward function 3 to the corresponding tooth 35.

Removal of the lower jaw nerve: After exposing the jawbone, drawing the nerve pathway of the lower jaw, using an ultrasound to cut a rectangular bone window 3 mm distant from the nerve, From function 4 to function 3, note that leaving 3mm of bone at the end of the jaw at the jaw 3 to position the grip and pull to avoid direct contact on the nerves will hurt it. After removal of the outer bones, the ivory scraper carefully removes the bone marrow, exposes the nerve bundle and separates it gently from the lower canal from the end of the jaw to the jaw. 4. 

Get pelvic bone, transplant bone vertically and place the implant.

Skin incision 5 cm above the front spine to avoid damage to the outer thigh, the incision on the iliac crest, through the subcutaneous tissue to the bone membrane, revealed the area of ​​the pelvis. Using ultrasound, cut four lines: the first line on the top of the serpent; the second line in front and the third line in the back and perpendicular to the line on the top of the iliac crest, the fourth line perpendicular to the second and third lines, four lines cut to form a rectangle. Use chisel to remove the bones of the block including the skeleton and osteophytes. Place spongel to stop bleeding. Two layers of stitching: stitched bone, then sewed under the skin.

Adjust the size of bone in accordance with the receptor graft, fix the bone block with screw diameter of 1.2mm. 

Bone implant placed 4 implant Tekka (France) at 4 teeth positions 46, 44, 31 and 33. The implant size is 4.0 x 11.5mm, 4.0 x 10mm, 4.5 x 10mm and 3.5 x 11.5 mm. bones in the remaining gaps between the bone mass and the graft site. Cover the bone with a collard membrane (Salvin oralmem®absorbable collagen membrane), so that the posterior nerve is in the mucosa.

Postoperative care:

Patients were hospitalized 1 day after surgery, taking antibiotics for 7 days (augmentin 2g / day, flagyl 1.5g / day), painkiller for 5 days and oral hygiene with chlorhexidine 0.2% in 2 weeks.

Gingival and bottoming of the corridor:

After 2 months of complete healing soft tissue surgery, grafting gingival and gingival corneal. Surgical removal of the gingival recess in the size of 40mm x 20mm, 1.5mm thickness. Then cut to pieces, each 40mm x 10mm. Recipes on the jaw and oral corridor should remove the epithelial layer of bleeding, rhinoplasty on this area and sewing with the fiber alone 6.0. 

Evaluation of neuroleptic results:

Neuronal lower abscess is removed from the lower canal and displaced from the corresponding R32 region to the distal R47 region in a gentle and safe manner. As a result, numbness recovers rapidly: patients numb more often during the first 5 days after surgery and recover 90% a week after surgery, 2 months after the patient has a reduction of numbness of 97% and then, due to transplantation gingival alveoli and coronary corridors, patients with numbness back but recovered completely after 2.5 months.

Evaluation of bone grafting and implants:

- Implants are placed in place according to plan and achieve good initial stability (> 35N / cm).

- 4.5 months after neurosurgery and implants implantation, panorrhea and CT Cone beam imaging showed good bone integrity with no visible light around the implant. Surgical implants and healing screws indicate that the implant is immobile, painless, and grows around the implant shoulder.

Bone grafts are well integrated with the grafted bone in the lower jaw, and do not distinguish between the grafted bone and the grafted area.

- At the location for the pelvis, the patient was very painful in the first week after surgery but still walking, 3 weeks after the pain was 50% slightly painful, 2 months after complete pain, walking normally Wounds in the mouth and pelvic area are good, not open, no infection or fluid drainage.

Evaluation of the results of grafting and bottoming of the corridor:

- 2 months after gum transplantation has created the coronary corridor and live the jaw with toned and non-mobile gums.

III. Evaluation of prosthetic restoration on implant

Four months after implantation and implantation, we performed implant surgery and healed implants. Two weeks later, the implant was implanted, implanted, and invented. Result of denture is very stable and gingival horns around the implant is very firm (no pocket and no bleeding gums when examination), patients eat well, no pain. (Fig. 14, 15, 16)

IV. Discuss

Liposuction is a complication usually occurs after surgery to remove the lower back nerve but with different rates and recovery time. The use of a high-quality dialysis instrument, such as the study of Rosequist 1992, had 23% of lipologic patients after 6 months and 6% of patients remained numb after 18 months. In Hashemi 2010, 13.6% of patients undergoing liposuction after 2 months and 2.8% of liposuction patients remained after 1 year.

However, the use of ultrasonal bone scanners for lower incidence of complications and faster recovery time, such as Fernandez's 2013 study, found that 5 out of 15 patients, 9 out of 19 (47, 4%) restoration of the nerve in the first week, 2 months later, 14/15 patients, 18/19 position (94.7%) complete nerve restoration.

Our clinical cassette also uses ultrasonic bone cutting machines, which are thought to be less neurological than rotary instruments [4]. Also in this case, we moved the entire nerve from the end of tooth 31 to tooth 47, thus creating a free head that helps to tighten the nerve fibers than to stretch the nerve fibers to side as in the study of a nerve passage behind the chin hole [2, 5, 7]. In addition, while removing the outer shell, we left approximately 3mm of bone with the end of the nerve end, which was used as the forearm to clip and move the nerve from front to back, so it did not touch directly the god. When moving to reduce injury. Thus, the neuropathy in this patient recovered completely and rapidly: the numbness level decreased by 90% a week after surgery, two months after the reduction of 97%. However, two months later we had a gum transplant so the patient returned numbness but recovered completely after 2.5 months of grafting. Thus, the total time from neurologic restoration to complete recovery was 4.5 months, faster than the studies of the above authors [2,5,7,8]. Thought, if there is no gum transplant surgery perhaps the recovery of the neuropathy is even faster.

In this case, the neurologist has a special surgical pathway: it crosses the middle line. Meanwhile, according to Mraiwa 2013 [9], neurology was detected at 86% of cases, usually ending at the tip of the lateral incisors and only to the median at 18% Our present case in this case, the median nerve passing through the midline may explain that it needs to grow longer to accomodate the sensation of function 3 since this function has been previously damaged and replaced. With grafted bone, there is no nerve inside.

A potential problem in the posterior area of ​​the lower jaw is the poor initial implantation of the implant, the incidence of crowns and crowns is not appropriate if the implant is short to ensure no nerve contact. In this clinical case, by implantation of the nerve at the same time combined with pelvic implants, implants of appropriate length and diameter (4.0 x 11.5mm, 4.0x10mm, 4.5x 10mm and 3.5 x 11.5mm). The implant placed near the lower jaw bone should be anchored to block the bone in all three parts: the tip, the body and the implant collar, so the implant has a good initial stability.

In longitudinal ventricular septal graft surgery, we use bone masses including bone marrow and skeletal bone, bone marrow to the surface of the lower jaw to take advantage of the bone healing properties of the bone marrow because of its high bone formation and growth factors, while the bony shell with rigid mechanical characteristics is turned outward, limiting bone loss. Thus, after 4.5 months of bone healing and good implant integration, no bone around the implant, but the problem of bone around the implant will continue to track longer in the future. Implants perform a good prosthetic function and implants are linked together to increase the ability to withstand force overload on implant compared to the case of individual implant.

Gingival hyperplasia (whole lower jaw) is a complicated technique because it requires large grafts on the gawker, which can cause bleeding. To control this disease, we performed a plastic gut covering the teeth and the entire prosthesis, in combination with a topical stain. In addition, adhere to the technique of grafted gingivitis to avoid the movement of grafted tissue in the function of the lower jaw should have achieved success. The transplantation of the hornbill improves the soft tissue around the implant, which plays an extremely important role in the long-term success of the implant, as it avoids inflammation, gum loss, and loss of bone around the implant.

V. Conclusion

Lower abdominal implantation for implantation of appropriate lengths, transplantation of the iliac crest, transplantation of horned gingival reconstruction and implant restoration on implants is a feasible and effective method, particularly in Situations of patients with severe bone loss that other methods can not be applied. 
Patients are satisfied with the restoration of the teeth on the implant because of its retention and stability as well as good chewing function. 
This technique can be practiced in Vietnam and is highly applicable because it is suitable for patients with severe bone loss due to loss of teeth and implanted dentures. 
Doctors need to have good experience and skills. At the same time, it is necessary to explain in advance to the patient about possible complications such as neuropathy, broken jaw.


Jensen O., Nock D. (1987). Inferior alveolar nerve repositioning in conjunction with placement of osseointegrated implants: a case report.Oral Surg Oral Pathol, 63 (3): 263-8. 
2. Rosenquist B. (1994). Implant placement in combination with nerve transpositioning: experiences with the first 100 cases.Int J Oral Maxillofac Implants, 9: 522-31. 
3. Nocini PF, De Santis D., Fracasso E. (1999). Clinical and electrophysiological assessment of inferior alveolar nerve function after lateral nerve transposition. Clin Oral Implants Res, 10 (2): 120-30. 
4. Metzger MC, Bormann KH, Schoen R., et al (2006). Inferior alveolar nerve transposition - an in vitro comparison between piezosurgery and conventional bur use. J Oral Implantol, 32 (1): 19-25.
5. Hashemi HM (2010). Neurosensory function following mandibular nerve lateralization for placement of implants.Int J Oral Maxillofac Surg, 39: 452-6. 
6. Fernández Díaz J., Naval Gías L. (2013). Rehabilitation of edentulous atrophic posterior: inferior alveolar nerve lateralization by piezotome and immediate implant placement.Int. J. Oral Maxillofac. Surg., 42: 521-6. 
7. Del Castillo P. de Vera JL, Chamorro Pons M., Cebrián Carretero JL (2008). Repositioning of the inferior alveolar nerve in cases of severe mandibular atrophy. A clinical case. Med Oral Patol Oral Cir Bucal, 13 (12): 778-82. 
Ferrigno N., Laureti M., Fanali S. (2005). Inferior alveolar nerve transposition in conjunction with implant placement. Int J Oral Maxillofac Implants, 20, 610-20.
9. Mraiwa N., Jacobs R., Moerman P., et al. (2003). Presence and course of the incisive canal in the human mandibular interforaminal region: Two-dimensional imaging versus anatomical observations. Surg Radiol Anat, 25: 416-23.


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