Complications associated with inferior alveolar nerve repositioning for dental implant placement: a systematic review

Persistent numbness of the lower lip and chin due to inferior alveolar nerve injury after implant placement: A clinical report

The number of dental implants placed and restored every year is increasing across the world. However, there has been an increase in the number of reports with implant-related surgical complications in which the inferior alveolar nerve injury is the most serious one. This surgical problem can be avoided by using cone beam computed tomography (CBCT), three-dimensional (3D) implant planning software, and computer-aided design and computer-aided manufacturing (CAD-CAM) technology such as stereolithographic surgical guides. The objective of this report is to present the clinical and radiologic findings of a female patient with the injury of inferior alveolar nerve after implant insertion where CBCT has not been used prior to implant placement.

Mandibular Fixed Prosthesis With a 3D-Printed Subperiosteal Implant: A Case Report

This case report aims to present the successful restoration of the atrophic partially edentulous posterior mandible using custom-made subperiosteal implants. The fixed prosthesis restoration was achieved using computer-aided design and computer-aided manufacturing technologies and 3D metal printing methods. The partially edentulous 58-year-old patient expressed a preference not to undergo bone augmentation procedures. The patient with teeth in the anterior mandible was treated with 2 separate custom-made subperiosteal implants. A custom-made implant was fabricated from sintered titanium using machined subperiosteal implants with a universal external connection. Subperiosteal implants offer several advantages over conventional bone grafting plus intraosseous implant placement techniques, such as the simple, 1-step procedure for atrophic jaws, streamlining the treatment process and reducing the overall time involved. Treatments using subperiosteal implants can be an alternative solution for individuals with severely atrophic jaws. Longer term studies in a larger sample are warranted to corroborate previous reports.

Implant-prosthetic rehabilitation of the atrophic posterior mandible with additively manufactured custom-made subperiosteal implants: a cohort study

The aim of this study was to retrospectively analyse a series of patients with posterior mandibular atrophy rehabilitated with custom-made subperiosteal implants. The study included patients with severe posterior mandibular atrophy who had undergone rehabilitation with subperiosteal implants between September 2018 and August 2022 in the Maxillofacial Surgery Operative Unit of the University Hospital of Sassari. Complications and the success rate were reviewed. Data from 30 implants placed in 17 patients were included and analysed. There were no major complications during the surgeries. The main postoperative sequela was oedema, which was reported as moderate by most patients and had completely regressed within 10 days of surgery. No partial or complete exposures, infections, or loss of the implants were detected during follow-up (average follow-up 22.5 months). Control computed tomography scans, performed at 6 months and then annually in all cases, did not show significant bone loss below the abutments, displacement of the implants, or loss or loosening of the osteosynthesis screws. Subperiosteal implants may represent a safe and reliable technique for the rehabilitation of severe atrophy of the posterior mandible. Prospective studies with a long follow-up will be needed to establish the long-term results of this type of implant-prosthetic rehabilitation.

Buccally or Lingually Tilted Implants in the Lateral Atrophic Mandible: A Three-Year Follow-Up Study Focused on Neurosensory Impairment, Soft-Tissue-Related Impaction and Quality of Life Improvement

Background and Objectives: In the severely resorbed posterior mandible, implant placement requires either bone regenerative procedures, subperiosteal implants or short implant placement with drawbacks including morbidity and increased treatment costs and duration. To overcome these inconveniences, some unconventional alternatives have been suggested, such as buccally or lingually tilted implants in the lateral mandible, bypassing the inferior alveolar nerve. The aim of the present retrospective study was to evaluate the three-year survival rate of implants inserted in the posterior atrophic mandible, bypassing the inferior alveolar nerve. The assessment was focused on the occurrence of postoperative complications related to neurosensory impairment and soft tissue impaction, as well as overall improvement in quality of life. Materials and Methods: Patients with severe bone atrophy in the lateral area of the mandible were included in the present study. Only the implants tilted either buccally or lingually to bypass the inferior alveolar nerve were analysed. The relation between peri-implant soft tissue and the healing abutment was assessed and a secondary revision surgery was performed when indicated. The Semmes–Weinstein pressure neurological test was used for qualitative assessment of inferior alveolar nerve function and the Geriatric Oral Health Assessment Index (GOHAI) was used for evaluating Oral-Health-Related Quality of Life (OHRQoL). Results: Fourteen implants were placed in nine patients during the evaluation period. Survival rate was 100%, temporary paraesthesia occurred in one patient and a limited definitive paraesthesia was seen in another patient. Mild or significant discomfort related to soft tissue impaction with healing abutment was observed in six out of nine patients. A statistically significant OHRQoL improvement was observed in all patients. Conclusions: Despite the limited number of patients and observation time, insertion of implants buccally or lingually bypassing the inferior alveolar nerve is a predictive treatment option for patients with severe bone atrophy in the posterior mandible.

Dynamic navigation system-guided trans-inferior alveolar nerve implant placement in the atrophic posterior mandible: A case report

BACKGROUND

In atrophic posterior mandibular areas, where the bone height superior to the inferior alveolar nerve (IAN) is less than 6 mm, short implants are not applicable. Conventional alternatives such as IAN transposition and various alveolar bone augmentation approaches are technically demanding and prone to complications.

CASE SUMMARY

Computer-guided dynamic navigation implantation improves the accuracy, predictability, and safety of implant placement. This case report presents a dynamic navigation system-guided trans-IAN implant placement technique, which can successfully treat a posterior mandibular dentition defect when the bone height is only 4.5 mm. The implant was inserted into the buccal side of the IAN and was 1.7 mm away from the IAN. The implantation deviations were controlled within a satisfying range, and the long-term restoration outcome was stable.

CONCLUSION

Dynamic navigation system-guided trans-IAN implant placement might be a recommended technique for patients with extremely insufficient residual bone height and sufficient bone width in the posterior mandibular area.

In-Block Lateralization as a New Technique for Mobilization of the Inferior Alveolar Nerve: A Technique Case Series

The edentulous atrophic posterior mandible is often a great challenge for implant rehabilitation. Although a number of treatment options have been proposed, including the use of short implants and surgical grafting techniques, in cases of severe bone atrophy, techniques for mobilization of the inferior alveolar nerve (IAN) have been shown to be efficient, with good results. Four female patients underwent IAN lateralization for prosthetic rehabilitation of the posterior mandible from 2013 to 2019, with 3 years to 5 years and 3 months of follow-up. This case series describes a new technique for mobilization of the IAN, named in-block lateralization, to facilitate access to the IAN and to reduce nerve manipulation. The implant is immediately installed (allowing nerve lateralization in unitary spaces), and the original mandibular anatomy is restored with autogenous bone from the original bed during the same surgical procedure. When well indicated and well performed, this new approach provides better and easier visualization of the IAN and safer manipulation aiming to achieve good results for implant stability and minimal risk of neurosensory disturbances, allowing rehabilitation even in unitary spaces.

Rehabilitation of extremely atrophic edentulous mandible in elderly patients with associated comorbidities: a case report and proof of concept

Background

Oral rehabilitation of the atrophic mandible is, most of the time, a challenging procedure, especially in elderly patients with associated comorbidities.

Case presentation

This clinical report describes the rehabilitation of an extremely atrophic mandible using an overdenture supported by four splinted implants, two of which are placed in the interforaminal region and the other two bypassing the inferior alveolar nerve at the level of the antegonial notch. A passive-fit bar structure splinting the four inserted implants was designed to compensate for mandibular flexure, to reduce the amount of strain on the implants, and avoid bone resorption and prosthetic failure. The 14-month postoperative cone-beam computed tomography (CBCT) and the clinical follow-up showed the bilateral integrity of the inferior alveolar nerve and the successful restoration of the atrophic edentulous mandible with a significant improvement in the patient’s quality of life.

Conclusions

The applied technique depicts several benefits such as a minimally invasive approach, reduced number of surgical interventions, reduced total treatment time, reduced treatment costs, and higher psychological acceptability.

Dental implant placement with inferior alveolar nerve repositioning in severely resorbed mandibles: a retrospective multicenter study of implant success and survival rates, and lower lip sensory disturbances

Background

The purpose of this study was to analyze medium-to-long-term implant success and survival rates, and lower lip sensory disturbance after placement of dental implants with simultaneous inferior alveolar nerve (IAN) repositioning.

Methods

Fifteen patients (3 men, 12 women) treated in two centers were included in this retrospective study. The ages of the participants ranged from 19 to 68. A total of 48 dental implants were placed in 23 posterior mandibular segments simultaneously with IAN transposition or lateralization. The residual bone above the IAN ranged from 0.5 to 7.0 mm. Crestal bone changes were measured using cone beam computed tomography (CBCT) images. Disturbance of the IAN was evaluated subjectively using a modified questionnaire.

Results

The healing process was uneventful in fourteen patients. In one patient, spontaneous fracture of the operated mandible occurred on tenth day after the surgery. The implant in the fracture line was removed at the time of open reduction and fixation. One more implant was lost after 5 years of loading. Therefore, the overall dental implant survival rate was 95.8%, whereas all implants in function were judged as successful after a follow-up period of 1 to 10 years. Transient neurosensory disturbances (ND) were observed in all patients who underwent IAN lateralization and IAN transposition. At follow-up times of 3 years, 5 years, and 10 years, weak hypoesthesia remained in two subjects treated with IAN transposition. None of the patients developed neuropathic pain after the procedure.

Conclusions

Within the limitations of this study, we conclude that reconstruction of severely resorbed mandibles with dental implants in conjunction with IAN repositioning is an effective and reliable technique. Although neurosensory disturbances are the most common complication after surgery, they tend to resolve over time. Advanced surgical skills are required to perform this technique.

Evaluation of the effect of the lateralized inferior alveolar nerve isolation and bone grafting on the nerve function and implant stability. (Randomized Clinical Trial)

BACKGROUND

The inferior alveolar nerve lateralization (IANL), although allows for an implant full-length mandibular height engagement, coincides with depleting the buccal bone support and sensory deficits.

PURPOSE

This study aims to assess whether interposing a bone graft coupled with securing a collagen membrane separation between the inferior alveolar nerve (IAN) and the underlying dental implants would preserve the nerve function, enhance the implant stability, and minimize the radiographic marginal bone loss.

MATERIAL AND METHODS

Eighteen patients with 30 atrophic mandibular edentulous ridges were subjected to IANL after being randomly assigned to two treatment modalities which consisted of 15 patients each. The (control group) utilized conventional IANL in direct contact with 20 implants. The (test group) implemented the IAN collagen-membrane wrapping and interposing bone graft to overlay 23 implants. The neural function, the radiographic marginal bone loss, and the implant stability quotient were assessed and compared 6 months postoperatively.

RESULTS

All the patients regained their full neurosensory function after 6 months, with statistically nonsignificant differences between both groups throughout the follow-up period. The mean marginal bone loss in the test group was (0.42 ± 0.09) mm versus (0.38 ± 0.14) mm for the control group, which was statistically similar (P = 0.401). The 6-month postoperative mean implant stability quotient values of the test group recorded (74.73 ± 2.68) versus (74.73 ± 1.79) for the control group, which was statistically nonsignificant with a value of P = 0.626.

CONCLUSION

The interposed bone graft, coupled with the collagen membrane isolation, neither subsided the neural disturbances nor enhanced the secondary implant stability and marginal bone loss.

The Role of Custom-made Subperiosteal Implants for Rehabilitation of Atrophic Jaws - A Case Report

Rehabilitation of atrophic jaws with conventional endosseous implant-supported overdentures and immediate loading protocols still presents a challenge nowadays. Custom-made implants with immediate loading overdenture are emerging as a solution for atrophic jaws rehabilitation. The authors describe the case of a 44-year-old male with a history of congenital dental agenesis. A previous oral rehabilitation with an all-on-6 type, implant-fixed mandibular overdenture, had failed due to peri-implantitis. The patient was successfully treated with bimaxillary custom-made subperiosteal implants with an innovative design, combining subperiosteal and endosseous support. The authors consider custom-made subperiosteal implants, in selected patients, present several advantages over classic bone-grafting plus endosseous implant-placement techniques such as (1) possibility of a single-stage procedure with immediate loading in atrophic jaws; (2) possible primary option to approach atrophic jaws as a simpler and less time-consuming technique; and (3) a valid rescue option for failed endosseous implants. More long-term studies with large samples of patients will be necessary to confirm previous assumptions.

Complications Associated with Rehabilitation of a Unilateral Partially Edentulous Mandible with Inferior Alveolar Nerve Transposition and Implant Placement: A Clinical Report

Rehabilitation of an edentulous posterior mandible to restore function and arch stability can be accomplished with a removable partial denture or an implant supported fixed partial denture. If the alveolus is severely resorbed, implant placement becomes challenging due to inadequate bone and the position of the inferior alveolar nerve. This report details a situation where a mandibular fracture occurred soon after inferior alveolar nerve (IAN) transposition and simultaneous implant placement. The prosthodontic reconstruction was completed using a fixed-dental prosthesis.

Guided bone regeneration in staged vertical and horizontal bone augmentation using platelet-rich fibrin associated with bone grafts: a retrospective clinical study

Background

The use of guided bone regeneration (GBR) for vertical and horizontal bone gain is a predictable approach to correct the bone defects before implant installation; however, the use of different protocols is associated with different clinical results. It is suggested that platelet-rich fibrin (PRF) could improve the outcomes of regenerative procedures. Thus, this study aimed to describe the bone gain associated with GBR procedures combining membranes, bone grafts, and PRF for vertical and horizontal bone augmentation.

Materials and methods

Eighteen patients who needed vertical or horizontal bone regeneration before installing dental implants were included in the study. The horizontal bone defects were treated with a GBR protocol that includes the use of a mixture of particulate autogenous and xenogenous grafts in the proportion of 1:1, injectable form of PRF (i-PRF) to agglutinate the graft, an absorbable collagen membrane covering the regenerated region, and leukocyte PRF (L-PRF) membrane covering the GBR membrane. The vertical bone defects were treated with the same grafted mixture protected by a titanium-reinforced non-resorbable high-density polytetrafluoroethylene (d-PTFE-Ti) membrane and covered by L-PRF. The bone gain was measured using a cone-beam computed tomography at baseline and after a period of 7.5 (± 1.0) months.

Results

All patients underwent surgery to install implants after this regenerative protocol. The GBR produces an increase in bone thickness (p < 0.001) and height (p < 0.005) after treatment, with a bone gain of 5.9 ± 2.4 for horizontal defects and 5.6 ± 2.6 for vertical defects. In horizontal defects, the gain was higher in the maxilla than in mandible (p = 0.014) and in anterior than the posterior region (p = 0.033). No differences related to GBR location were observed in vertical defects (p > 0.05).

Conclusion

GBR associated with a mixture of particulate autogenous and xenogenous grafts and i-PRF is effective for vertical and horizontal bone augmentation in maxillary and mandibular regions, permitting sufficient bone gain to future implant placement.

Trial registration

REBEC, RBR-3CSG3J. Date of registration—19 July 2019, retrospectively registered. http://www.ensaiosclinicos.gov.br/rg/RBR-3csg3j/

Superioralization of the Inferior Alveolar Nerve and Roofing for Extreme Atrophic Posterior Mandibular Ridges with Dental Implants

Introduction:

Posterior mandibular ridges with extreme atrophy are usually combined with superficial location of the mental nerve and inferior alveolar nerves (IAN) and with a short residual mandibular ridge. As a result, dental implants cannot be placed in conjunction with IAN transposition alone. The aim of this paper is to introduce a new treatment approach to treat those patients.

Patients and Methods:

Eleven patients with 18 extreme atrophic posterior mandibular ridges characterized by superficial location of the IAN and short residual ridge had been treated during a 4-year period. The treatment approach included superior transposition of the IAN (IAN superioralization), 18 onlay bone block grafts harvested from the calvarial bone, implants placement through the block, and repositioning of the nerve under the onlay graft (IAN roofing). Patients were examined every 2–3 weeks; they received panoramic radiograph immediately after the surgery, at 4 months, at 6 months, and then once a year. Fixed prosthesis was performed after 4–5 months.

Results:

The donor sites of the bone blocks healed very well. The increase of bone height ranged between 4 and 6 mm at the recipient sites, and 63 long implants were placed (10–13 mm). All the patients were hospitalized 1–3 days. The healing process was uneventful, and the nerve recovery lasted a maximal period of 6 months. The implant success and survival rates were 100%. All patients received fixed prosthesis. The functional outcomes were satisfactory with marked improvement in the quality of life of the patients. The follow-up period was 12–58 months.

Conclusions:

Superioralization of the IAN and roofing is a fast and predictable option to treat extremely atrophic posterior mandibular ridges with fixed prosthesis supported by dental implants.

Incidence of Neurosensory Disturbance and Success Rates of Solid-Screw Implants Placed in Conjunction with Inferior Alveolar Nerve Transposition

Background:

Implant-supported prosthetic rehabilitation of a severely atrophic posterior mandibular alveolar ridge is a real challenge. Implant placement in such situations is very difficult and implies the risk of inferior alveolar nerve (IAN) damage.

Purpose:

The purpose of this study is to evaluate the incidence of neurosensory disturbance and the cumulative survival of dental implants placed after the IAN transposition (IANT) procedures followed by dental implants placement.

Materials and Methods:

Twenty International Team for Implantology implants were placed in eight patients following unilateral IANT. In two patients, nerve transposition was performed bilaterally, and hence, a total of 10 IAN transposition surgeries were performed. Neurosensory dysfunction was objectively evaluated by using light touch test (LT), pain test (PT), and 2-point discrimination test (2-DT). In addition, patients were asked to answer a short questionnaire to investigate the individual feeling of discomfort and advantages related to this surgical technique. The mean follow-up periods were 47.1 months (range 12–78 months).

Results:

Neurosensory disturbance (i.e., disturbance registered by the LT, PT, and 2-DT tests) was experienced in 2 of 10 cases. The cumulative implant survival was 100%. However, at the time of data analysis (12–79 months after surgery), all patients indicated that they would go through the surgery again.

Conclusion:

IANT can permit the placement of implants with adequate length and good initial stabilization as used in routine sites, with the same favorable prognosis. All patients felt that they had received benefits from their new prostheses in terms of improved comfort, chewing efficiency, and esthetics.

Two-stage distalization of the mental foramen to manage posterior mandibular vertical bone deficiency-a prospective observational study

Inferior alveolar nerve (IAN) transpositioning is a modality utilized to manage posterior mandibular vertical deficiency. Several complications have been reported including improper implant positioning, mandibular body fracture, and neurosensory disturbance. The aim of this prospective observational study was to introduce a two-stage mental foramen distalization technique to minimize the complications associated with IAN transpositioning. Ten patients with severely atrophied mandibular ridges were included. Cone beam computed tomography was ordered to accurately locate the position of the IAN and its incisive terminal branch before designing the outline of two cortical osteotomies anterior and posterior to the mental foramen. The osteotomies were created using a piezoelectric device, followed by separation and identification of the nerve. The incisive branch was severed to freely transpose the IAN. A new foramen was created far distally and the cortical windows were repositioned and fixed with two screws. Healing was uneventful for all patients. Neurosensory recovery was assessed by MRC scale. All cases showed full recovery within 6 weeks, except for two patients who showed complete recovery after 16 weeks. Four months postoperative, all patients showed complete consolidation of the cortical windows without any signs of failure implants were placed at the pre-planned surgical sites. Histomorphometric analysis of core biopsies from seven surgical sites showed bone area percentages ranging from 46% to 63%. The two-stage mental foramen distalization technique is a predictable and safer technique for IAN transpositioning specifically in cases of vertical bone deficiency associated with limited inter-arch space.

Complications associated with inferior alveolar nerve reposition technique for simultaneous implant-based rehabilitation of atrophic mandibles. A systematic literature review

INTRODUCTION

Surgical inferior alveolar nerve (IAN) reposition techniques offer an alternative approach to implant-based rehabilitation in patients with severe mandibular atrophy The aim of this systematic review, was to determine the complications associated with the technique and to determine which of two variants (lateralization or transposition) is less invasive.

MATERIALS AND METHODS

An electronic search was conducted in databases complimented by a manual search to identify clinical studies investigating complications derived from these surgical techniques. Only studies of adult humans, published in English during the last seven years were included. The initial search located 78 articles, of which seven were included in analysis on the basis of the following characteristics: four investigated inferior alveolar nerve lateralization (IANL), one inferior alveolar nerve transposition (IANT), and two investigated both reposition techniques.

RESULTS

This review included data from 289 patients who were recruited for lateralization (N=319) or transposition surgery (N=33) making a total of 352 reposition procedures. Five patients (1.73%) suffered persistent damage to the IAN at the end of the follow-up periods. The overall implant survival rate was 99.26% of a total of 817 implants. The most common complications were neurosensory problems, mandibular fracture, infection, implant loss, and insufficient anatomical reconstruction of the atrophic mandible; neurosensory complications (hypoesthesia, paraesthesia, and hyperesthesia caused by traumatic damage to the nerve) were the most prevalent.

CONCLUSIONS

Lateralization of the inferior alveolar nerve would appear to be less invasive as it produces lower percentages of persistent neurosensory disorders (1.56%) than transposition (12.12%). Nevertheless, both techniques offer a viable approach to implant placement in edentulous atrophic mandibles, obtaining predictable clinical and radiological results after 5 years implant loading.

The adjuvant use of plasma rich in growth factors in the inferior alveolar nerve repositioning technique

Purpose

To describe the outcomes of the adjuvant use of plasma rich in growth factors (PRGF) in the inferior alveolar nerve repositioning surgery.

Material and methods

A retrospective report of three cases was conducted in a single private dental clinic. The variables were the residual alveolar bone height, the surgical complications, the occurrence of neurosensory complications, the marginal bone stability and the implant survival. A descriptive statistical analysis was performed.

Results

Three inferior alveolar repositioning were performed with the adjuvant use of PRGF. The residual alveolar bone height was 2.2 ± 0.14 mm. All patients underwent uneventful healing with no symptoms of neurosensory complications neither implant failure. The marginal bone loss was 0.1 ± 0.4 mm

Conclusions

The preventative and adjuvant use of PRGF in inferior alveolar nerve repositioning need to be assessed in prospective studies with a larger sample size.

Evaluation of Neurosensory Function Following Inferior Alveolar Nerve Lateralization for Implant Placement

Background

Adequate bone height and width is the most important parameter for success of implants. Prolonged edentulous area in mandibular posterior region is often associated with atrophy precluding the use of dental implants. Inferior alveolar nerve (IAN) lateralization is a challenging surgical procedure as it involves the exposure of the neurovascular bundle from its compact bony compartment and adequate retraction while immediate placement of implant.

Aim

Evaluation of neurosensory disturbances related to IAN lateralization for implant placement in the posterior atrophic edentulous mandible.

Materials and Methods

Ten patients above the age of 18 years with an edentulous span in mandibular posterior region showing distance from alveolar crest to IAN ≤ 8 mm (CBCT) were included in the study. The postoperative analysis of NDs was done using Semmes-Weinstein Monofilaments (SWM). Readings were made on the 1st and 7th postoperative day and every month thereafter until the neural sensations were restored.

Results

All patients reported neurosensory disturbance on post-op day 1. None of the patients responded to SWM lesser than 4.56 on first postoperative day, which indicated 100% incidence of neurosensory disturbances. The minimum time required for complete recovery was 2.0 months, and maximum was 4.0 months.

Conclusion

IAN lateralization is a useful method for managing the atrophic posterior mandible with dental implants. If done precisely with experienced personnel, it can provide a worthy option for surgical restoration of atrophic mandible with minimal temporary NDs.

Piezoelectric Surgery in the Inferior Alveolar Nerve Lateralization With Simultaneous Implant Placement: A Case Report

The aim of this case report was to describe the inferior alveolar nerve (IAN) lateralization technique using the piezoelectric device for the posterior rehabilitation of an atrophic mandible with implants. The patient presented the absence of elements 35 and 36 associated with a vertical defect impairing the adequate dental implant placement without IAN damage. A full-thickness mucoperiosteal flap was raised, and a bone window was made with a piezoelectric device centralized on the IAN canal position. After dissection, the IAN was moved buccally with a sterile elastic strip. Morse cone 4.0 × 1.5-mm implants were inserted while the IAN remained retracted. At the 4-month follow-up, the screw-retained prosthesis was installed guaranteeing the recovering masticatory function. In conclusion, the case report showed that the IAN lateralization performed with an adequate surgical technique can be successfully indicated for longer implant placement in edentulous atrophic posterior mandible with no permanent neural damage.

Management of Limited Vertical Bone Height in the Posterior Mandible: Short Dental Implants Versus Nerve Lateralization With Standard Length Implants

Inferior alveolar nerve lateralization (IANL) and short dental implants (SDI) are 2 viable implant-based treatment approaches in the presence of atrophied posterior mandible. Despite the risks of dysfunction, infection, and pathologic fractures in IANL, it becomes possible to place standard implants. The purpose of this study was to compare SDI and IANL approaches from clinical and radiographic aspects. Fifteen subjects having unilateral atrophic mandibles were allocated to SDI and IANL treatment groups. Following surgical procedures, early postoperative complications, implant survival, and periimplant clinical and radiographic parameters including probing pocket depth, attachment level, keratinized tissue amount, vertical tissue recession, and marginal bone loss were recorded at baseline and 1-year after prosthetic rehabilitation. In both groups, no implant was lost. Except usual postoperative complications, 2 patients had transient paraesthesia after IANL. According to time-dependent evaluation, both groups showed significant increase in probing pocket depth and attachment level at 1-year follow-up compared with baseline (P < 0.05). Except a slight but significant increase in mesial surface of SDI group (P < 0.05), no remarkable time-dependent change was identified in vertical tissue recession. Keratinized tissue amount did not exhibit any inter- or intragroup difference during whole study period. Marginal bone loss did not show any difference between IANL and SDI groups at follow-up. SDI placement or standard length implant placement with IANL can be considered promising alternatives in the treatment of atrophic mandibular posterior regions. However, SDI may be preferred in terms of lower complication risk.

Transalveolar Osteotomy of the Mandibular Canal Wall for the Treatment of Severely Atrophied Posterior Mandible

PURPOSE

Treatment of severe bone atrophy of the posterior mandible requires an advanced surgical bone augmentation technique. This report describes a minimally invasive approach for a residual alveolar height less than 5 mm.

MATERIAL AND METHODS

A retrospective case series was conducted in a single private dental clinic. Outcome variables were dental implant survival rate, intraoperative complications, occurrence of neurosensory disturbances, and marginal bone loss. Descriptive analysis was performed for patients' demographic data, postoperative healing, and implant details. Kaplan-Meier method was used to assess the implant survival rate.

RESULTS

The mean age of the 19 patients was 60 ± 13 years. Twenty-eight implants (5.5 mm long) were placed in a residual alveolar bone height of 4.5 ± 0.6 mm. The implant survival rate was 96% at 5-year follow-up.

CONCLUSIONS

Extra-short implants and transalveolar preparation of the inferior alveolar cortical bone could be a safe and effective treatment of severe mandibular atrophy.

The influence of initial alveolar ridge defect morphology on the outcome of implants in augmented atrophic posterior mandible: an exploratory retrospective study

OBJECTIVES

Clinicians commonly consider atrophic site topography as an important determinant in deciding the augmentation technique to utilize, as well as forecasting the likelihood of success. The purpose of this retrospective study was to examine the influence of initial atrophic posterior mandible morphology on the outcome of implants placed following augmentation.

MATERIALS AND METHODS

A total of 52 patients contributed 71 edentulous sites, and 185 implants were placed with mean follow-up of 37.97 months. The initial defect morphology was classified according to ABC classification (Journal of Oral Implantology, 37, 2013a and 361). Ridge augmentation was performed by "cortical autogenous tenting" (CAT) followed by either simultaneous or delayed implant placement after 4-6 months of healing. The European Academy of Osseointegration success criteria were used to evaluate implant outcomes.

RESULTS

The overall survival and success rates of dental implants were 98.91% and 80%, respectively. Cumulative success and survival rates in CAT group were 95% and 100% after 2 years of follow-up. The highest marginal bone loss (MBL) was observed (1.26 mm ± 0.99) around implants placed in augmented edentulous sites with initially narrow and flat alveolar crest (defect class CII). Conversely, least MBL (0.48 mm ± 0.78) was detected around implants placed into edentulous sites with two sloped boney walls (defect class AII). Differences between MBL observed around implants placed into initial defect class C, initial defect type and class A (I, II), as well as class BII, were statistically significant (P < 0.05). Among all implants, 148 were considered as successful, 26 exhibited satisfactory survival, nine with compromised survival, and two implants failed.

CONCLUSION

The present data confirmed the effect of initial ridge morphology on the outcome of implants placed into augmented bone. Specifically, class A and class B atrophic ridge defects, with one and two vertical boney walls, respectively, may be considered as more favorable recipient sites than class C defects with flat morphology. This conclusion is based on least MBL around implants placed into initial defect class A and class B augmented sites, and higher MBL in implants placed into class C recipient sites. A randomized controlled trial is warranted to examine these exploratory observations.

Interventions for Dental Implant Placement in Atrophic Edentulous Mandibles: Vertical Bone Augmentation and Alternative Treatments. A Meta-Analysis of Randomized Clinical Trials

BACKGROUND

The purpose of the current study is to assess which vertical bone augmentation techniques are most effective for restoring atrophic posterior areas of the mandible with dental implants and compare these procedures with alternative treatments.

METHODS

Electronic literature searches in PubMed (MEDLINE), Ovid, and the Cochrane Library were conducted to identify all relevant articles published up to July 1, 2015. Eligibility was based on inclusion criteria, and quality assessments were conducted. The primary outcome variables were implant and prosthetic failure. After data extraction, meta-analyses were performed.

RESULTS

Out of 527 potentially eligible papers, 14 randomized clinical trials were included. Out of these 14 studies, four trials assessed short implants (5 to 8 mm) as an alternative to vertical bone augmentation in sites with a residual ridge height of 5 to 8 mm. No statistically significant differences were found in implant (odds ratio [OR]: 1.02; 95% confidence interval [CI]: 0.31 to 3.31; P = 0.98; I²: 0%) or prosthetic failure (OR: 0.64; 95% CI: 0.21 to 1.96; P = 0.43; I²: 0%) after 12 months of loading. However, complications at treated sites increased with the augmentation procedures (OR: 8.33; 95% CI: 3.85 to 20.0; P <0.001; I²: 0%). There was no evidence of any vertical augmentation procedure being of greater benefit than any other for the primary outcomes (implant and prosthetic failure).

CONCLUSIONS

Short implants in the posterior area of the mandible seem to be preferable to vertical augmentation procedures, which present similar implant and prosthetic failure rates but greater morbidity. All the vertical augmentation technique comparisons showed similar intergroup results.

The effect of a platelet-rich fibrin conduit on neurosensory recovery following inferior alveolar nerve lateralization: a preliminary clinical study

This retrospective study aimed to assess the recovery of neurosensory dysfunction following modified inferior alveolar nerve (IAN) lateralization surgery compared to the conventional approach. Data from two groups of patients who underwent IAN lateralization in 2014 were included in this study. In one group, platelet-rich fibrin was placed over the IAN and this was protected with a collagen membrane conduit; the other group underwent the conventional IAN lateralization procedure. Implants were placed immediately. Neurosensory dysfunction was evaluated at 3, 6, and 12 months post-surgery. Demographic, neurosensory disturbance (NSD), subjective two-point discrimination test (TPD), and static light touch test (SLT) data were obtained. Twenty-three IAN lateralization procedures with the placement of 51 implants were performed in 14 patients. At the 6-month follow-up, the number of patients experiencing normal sensation was greater in the modified surgery group, but the 12-month follow-up results were the same in the two groups. More precise sensation was observed with the TPD in the modified group at 6 months, and the modified group demonstrated better SLT scores at 6 months. Although the two groups had comparable results at the 12-month follow-up, it was observed that the modified technique accelerated neural healing within 6 months and reduced the length of the discomfort period.

Autogenous non-vascularized bone graft in segmental mandibular reconstruction: a systematic review

The restoration of mandibular bone defects with non-vascularized bone grafts depends on the diagnosis, anatomical site, extent of the defect, and the patient's age, as well as the surgeon's experience. The aim of this study was to perform a systematic literature review on mandibular reconstruction for segmental mandibular bone defects using non-vascularized bone grafts to answer the following question: Is there scientific evidence to support the use of this technique? The initial literature search in PubMed, Scopus, and Cochrane databases identified 862 articles. Of these, 25 were included in the final review. These articles encompassed 926 procedures with non-vascularized bone grafts; 76.1% were from the iliac crest. Benign tumours were the major cause of these defects (56.8%), and 44.7% of defects were located in the lateral mandibular area. Although this technique showed a high occurrence of complications (290 in 873 patients, some with more than one complication), these did not account for treatment failure. The restoration of bone defects due to malignant tumours treated with radiation therapy had lower success rates, and these appear to be a contraindication for the technique. Although standardized randomized controlled clinical studies are needed to obtain better clinical evidence for treatment choices in general, the use of non-vascularized bone grafts for mandibular reconstruction showed an 87.6% success rate in this review.

Subjective and qualitative assessment of neural disturbance after inferior alveolar nerve transposition for dental implant placement

BACKGROUND

The purpose of this retrospective study was to accumulate data regarding the quality of postoperative neurosensory function after inferior alveolar nerve (IAN) transposition for dental implant placement.

METHODS

The study included seven consecutive patients who underwent IAN transposition surgery for the insertion of a dental implant into the atrophic posterior mandible. Of these, six patients (seven sides) were available for long-term assessment of postoperative IAN function. Neurosensory disturbance of the IAN was assessed objectively using the modified SW perception test reported by Semmes and Weinstein. In addition, the quality of nerve paralysis was assessed according to the criteria reported by Highet.

RESULTS

The median follow-up time was 49 months (range 12-105 months). No implant loss was observed during the follow-up. All patients experienced numbness immediately and the days after surgery. Complete recovery of neural function was observed on two sides; weak hypoesthesia was observed on two sides, moderate hypoesthesia on two sides, and severe hypoesthesia on one side. However, only one patient expressed concern about IAN function.

CONCLUSIONS

IAN transposition is a useful method for placing implants in the atrophic posterior mandible. However, the procedure is complicated, with the possibility of some degree of neurosensory disturbance, although in most of our cases, it resolved within a clinically acceptable period.

Systematic Review and Meta-Analysis on Incidence of Altered Sensation of Mandibular Implant Surgery

Altered sensation (including paresthesia, dysesthesia and hypoesthesia) after mandibular implant surgery may indicate transient or permanent injury of the inferior alveolar nerve and the mental branch, and considerably lower patients’ satisfaction about the therapy. Previous studies have shown a great degree of variability on the incidence of altered sensation. We here reported the incidence of altered sensation after mandibular implant surgery based on a meta-analysis of 26 articles published between 1990.1.1 and 2016.1.1. Study quality and risk of bias was assessed and the studies with a lower score were excluded in the meta-analysis. Data synthesis was performed using the logistic-normal random-effect model. The meta-analyses revealed that the short-term (10 days after implant placement) and long-term (1 year after implant placement) incidence was 13% (95% CI, 6%-25%) and 3% (95% CI, 1%-7%), respectively. (2) For the patients who initially reported altered sensation, 80% (95% CI, 52%-94%) of them would return to normal sensation within 6 months after surgery, and 91% (95% CI, 78%-96%) of them would return to normal sensation one year after surgery. We concluded that dentist-patient communication about the risk of altered sensation is critical to treatment planning, since the short-term incidence of altered sensation is substantial (13%). When a patient reports altered sensation, regular assessment for 6 months would help tracing the changes of symptoms. In terms of long-term follow-up (1 year after surgery), the incidence is much lower (3%) and most patients (91%) would return to normal sensation.

Inferior Alveolar Nerve Lateralization and Transposition for Dental Implant Placement. Part II: a Systematic Review of Neurosensory Complications

Objectives

This article, the second in a two-part series, continues the discussion of inferior alveolar nerve lateralization/transposition for dental implant placement. The aim of this article is to review the scientific literature and clinical reports in order to analyse the neurosensory complications, risks and disadvantages of lateralization/transposition of the inferior alveolar nerve followed by implant placement in an edentulous atrophic posterior mandible.

Material and Methods

A comprehensive review of the current literature was conducted according to the PRISMA guidelines by accessing the NCBI PubMed and PMC databases, as well as academic sites and books. The articles were searched from January 1997 to July 2014. Articles in English language, which included adult patients between 18 - 80 years of age who had minimal residual bone above the mandibular canal and had undergone inferior alveolar nerve (IAN) repositioning, with minimum 6 months of follow-up, were included.

Results

A total of 21 studies were included in this review. Ten were related to IAN transposition, 7 to IAN lateralization and 4 to both transposition and lateralization. The IAN neurosensory disturbance function was present in most patients (99.47% [376/378]) for 1 to 6 months. In total, 0.53% (2/378) of procedures the disturbances were permanent.

Conclusions

Inferior alveolar nerve repositioning is related to initial transient change in sensation in the majority of cases. The most popular causes of nerve damage are spatula-caused traction in the mucoperiosteal flap, pressure due to severe inflammation or retention of fluid around the nerve and subsequent development of transient ischemia, and mandibular body fracture.