Neurosensory Deficits of the Mandibular Nerve Following Extraction of Impacted Lower Third Molars-A Retrospective Study

BACKGROUND

Neurosensory deficits are one of the major complications after impacted lower third molar extraction leading to an impaired patient's quality of life. This study aimed to evaluate the incidence of neurosensory deficits after lower third molar extraction and compare it radiologically to the corresponding position of the inferior alveolar nerve.

METHODS

In a retrospective study, all patients who underwent impacted lower third molar extraction between January and December 2019 were compiled. Therefore, clinical data as well as preoperative radiological imaging were assessed.

RESULTS

In total, 418 patients who underwent lower third molar extractions (n = 555) were included in this study. Of these, 33 (5.9%) had short-term (i.e., within the initial 7 postoperative days) and 12 (1.3%) long-term (i.e., persisting after 12 months) neurosensory deficits documented. The inferior alveolar nerve position in relation to the tooth roots showed apical position in 27%, buccal position in 30.8%, lingual position in 35.4%, and interradicular position in 6.9%.

CONCLUSIONS

A statistically significant increased incidence of neurosensory deficits occurs when the inferior alveolar nerve is directly positioned lingually to the tooth roots (p = 0.01).

Development of an oral health-related quality of life questionnaire on neurosensory disturbances after orthognathic surgery - a pilot study

OBJECTIVE

Development of a new questionnaire, Oral Health-Related Quality of Life - Neurosensory Disturbances after Orthognathic Surgery (OHRQL-NDO), designed to measure the effects of neurosensory disturbance (NSD) on patients' oral health-related quality of life (OHRQL) and to evaluate reliability and validity of this questionnaire.

MATERIALS AND METHODS

A questionnaire including 11 items was constructed. Thirty patients with NSD affecting the lower lip and/or chin following orthognathic surgery were included. Convergent validity was assessed by comparing OHRQL-NDO with OHIP-14 and two global questions. Test-retest reliability was assessed by asking the patients to complete OHRQL-NDO at two different occasions with an interval of two to three weeks.

RESULTS

The internal consistency, measured with Cronbach's alpha, was 0.84. The test-retest reliability, measured with ICC, was 0.89 (95% CI 0.77-0.95). The correlation between the mean sum score for the OHRQL-NDO and the mean sum score for the OHIP-14 was r = 0.75, using Pearson correlation coefficient. The correlations between the mean total score for the OHRQL-NDO and the global questions 1 and 2 were r = 0.74 and r = 0.72, respectively.

CONCLUSIONS

The current instrument OHRQL-NDO is a promising test, but needs further development to better capture the different aspects of OHRQL. Further tests of the questionnaire must follow in other samples to finalize the instrument.

Immediate postoperative complications after lateral ridge augmentation - a clinical comparison between bone shell technique and sticky bone

Nowadays, implant dentistry is strongly interconnected to bone augmentation procedures. Lateral ridge augmentation is often an imperative treatment stage for successful, prosthetic-driven implant placement. This study aimed to comparatively analyze the immediate postoperative complications of two horizontal bone grafting procedures: sticky bone and bone shell technique. Records of patients with lateral ridge augmentation were analyzed to identify immediate postoperative complications. The study group included 80 patients divided into 40 control (bone-shell technique - BS) and 40 tests (sticky bone -SB). More patients reported moderate and severe pain in the BS - group (11 patients - 27.5%) than in the SB group (6 patients - 15%). In the BS group, the incidence of severe and moderate trismus, neurosensory disturbances, and important hematoma was higher. There was an increased inflammatory response following the bone shell technique, while the sticky bone technique proved reduced surgical morbidity. There was no difference between the two groups in the risk of dehiscence or infection.

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.

Incidence of neurosensory disturbance in mandibular implant surgery - A meta-analysis

Aim

Implantology has been widely accepted as the mainstay treatment for rehabilitating complete and partial edentulism. However, it is associated with some failures and complications, the most concerning being neurosensory disturbance. Although neurosensory disturbance has been extensively studied, the incidence and cause remains largely variable. Thus, the aim of this systematic review and meta-analysis was to evaluate the incidence, distribution, and recovery rate of neurosensory disturbance.

Settings and Design

This systematic review was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. A structured literature review was conducted using the following databases: PubMed, Science Direct, Cochrane, Ovid, and Google Scholar for reports related to neurosensory disturbance experienced after implant placement in the mandible.

Statistical Analysis Used

Incidence and recovery rate for 100 person-years was calculated using the Poisson regression model. The risk difference of incidence between anterior and posterior implants was calculated with a random effects model.

Results

Electronic database search yielded 1589 articles; a total of nine articles were selected for the meta-analysis. The risk of neurosensory disturbance was estimated at 13.50/100 person-years (95% confidence interval (CI): 10.98-16.03), with a greater risk with anteriorly placed implants: -0.02 (95% CI: -0.21-0.16) (P = 0.05). The overall recovery rate was estimated at 51.30/100 person-years (95% CI: 31.2-71.4).

Conclusions

Within the limitations of the study, it can be concluded that mandibular implant placement is associated with a considerable risk of neurosensory disturbance. A large proportion of these patients present with spontaneous recovery; however, clinicians must take necessary precautions to avoid such complications. More randomized controlled trials are required to quantify the effect of factors leading to altered sensation during implant placement.

Inferior alveolar nerve canal position in relation to mandibular molars: A cone-beam computed tomography study

Objective

This study was carried out to prevent the risk of iatrogenic injuries to the inferior alveolar nerve (IAN) canal associated with various surgical interventions in the area of mandibular molars, by using cone-beam computed tomography (CBCT).

Materials and Methods

The present retrospective study was carried out by using CBCT of 100 patients between 18 and 40 years of age group. The linear measurements were made in relation to the 1^st and 2^nd mandibular molars on both the sides. Linear distances between buccal and lingual aspects to the mandibular, buccal, and lingual cortical bone thickness; IAN canal diameter; and the superior corticated border of the IAN canal from the periapex of the 1^st and 2^nd mandibular molars. The statistical evaluation was done using SPSS V.20 (SPSS: an IBM company), and P < 0.05 was considered statistically significant.

Results

Both genders of all age groups showed statistically significant result (P < 0.00). All the linear measurements were statistically significant in relation to both the 1^st and 2^nd mandibular molars (P < 0.005), and also the bilateral comparison of the linear measurements showed statistically significant difference in relation to the mandibular 2^nd molar (P < 0.03) and 1^st molar (P < 0.04) among both the sexes.

Conclusion

Clinicians should be aware of the proximity of root apices and cortical plates to the mandibular canal when performing surgical and root canal procedures in the posterior mandible to avoid serious nerve injuries.

Laser Biophotomodulation in Patients with Neurosensory Disturbance of the Inferior Alveolar Nerve After Sagittal Split Ramus Osteotomy: A 2-Year Follow-Up Study

OBJECTIVE

To evaluate the effect of the application of photobiomodulation in a 2-year follow-up period in patients who have been intervened with a sagittal ramus split osteotomy and present neurosensory disturbance of the inferior alveolar nerve.

BACKGROUND

Photobiomodulation is a common clinical tool in dentistry, for its beneficial effects have been shown in surgical and periodontal wound healing, reducing of swelling and pain, neurosensory recovery, and treatment of temporomandibular joint disorders.

METHODS

This is a 2-year follow-up study with an experimental (Laser) group (n = 33) that received photobiomodulation, and a control (Sham) group (n = 9), placebo. All patients from the Laser group received laser applications (continuous wave of 0.353 W/cm², 27 J in 270 sec per session) on days 1, 2, 3, 5, 10, 14, 21, and 28 after surgery. Neurosensory disturbance was evaluated with five tests: Visual Analog Scale (VAS) for pain and sensitivity, sensitivity threshold test, two-point discrimination, and thermal discrimination. All tests were performed before (24 h before surgery) and after surgery (24 h, 28 days, 60 days, 6 months, 1 year, 2 years, more than 2 years). Participants and evaluator were blinded to intervention. Variables were described with absolute frequencies, percentages, and medians. Ordinal and dichotomous variables were compared with Mann-Whitney's and Fisher's tests, respectively.

RESULTS

Clinical improvement was observed during the follow-up period for the Laser group; general VAS for sensitivity was normal in 11 participants from the Laser group at 2 years postsurgery (40.74%), while no participants from the Sham group achieved this (p = 0.0341). Twenty-three participants recovered initial values for two-point discrimination (69.7%) after 2 years of follow-up (p = 0.0025) as well as sensitivity threshold test. General VAS for pain was normal in 31 patients from the Laser group after 2 years of follow-up (93.94%, p = 0.0254).

CONCLUSIONS

Photobiomodulation was effective for neurosensory recovery on sample studied.

Retrospective study of changes in the sensitivity of the oral mucosa: sagittal split ramus osteotomy (SSRO) versus intraoral vertical ramus osteotomy (IVRO)

We investigated changes in the sensitivity of cutaneous points and the oral mucosa after sagittal split ramus osteotomy (SSRO) and assessed the differences between SSRO and intraoral vertical ramus osteotomy (IVRO). The subjects included in this study were 46 patients with mandibular prognathism who underwent IVRO (88 rami) and 30 patients who underwent SSRO (59 rami). An objective evaluation of the neurosensory status of each patient was completed preoperatively and at 1, 4, 8, 12, and 24 weeks postoperatively. Other variables studied for each patient included sex, age, magnitude of mandibular setback, and amount of blood loss during surgery. We found that a neurosensory recovery occurred earlier in the oral mucosa than at cutaneous points. The number of oral mucosa points showing reduced neurosensory function and neurosensory disturbance after SSRO was significantly higher than after IVRO at 1, 4, and 8 weeks (P<0.05). The nerve recovery observed after SSRO was delayed for a longer period than that noted in our previous study of IVRO. In conclusion, we found changes in sensitivity at cutaneous points and the oral mucosa after SSRO and assessed the differences between SSRO and IVRO.

Systematic review of preoperative mandibular canal position as it relates to postoperative neurosensory disturbance following the sagittal split ramus osteotomy

The purpose of this study was to review the current literature for the relationship between the preoperative position of the mandibular canal on three-dimensional (3D) radiographic imaging and postoperative neurosensory disturbance (NSD) following a sagittal split ramus osteotomy (SSRO). A literature search was conducted using PubMed, EMBASE, and the Cochrane Database for articles published from 1 January 2000 through 31 December 2013. Studies that included preoperative 3D imaging and assessment of NSD after surgery were reviewed. Study sample characteristics and results were extracted. Of the 69 articles identified, seven met the inclusion and exclusion criteria. There was no standardization for measuring the canal position or for evaluating NSD. General consensus was that the less space between the mandibular canal and the outer border of the buccal cortex the more frequent the occurrence of NSD. Increased bone density also appeared to contribute to a higher incidence of NSD. Utilization of 3D images to locate and measure the position of the mandibular canal is not standardized. Advances in 3D imaging and evaluation tools allow for new methodologies to be developed. Early attempts are informative, but additional studies are needed to verify the relationship between the location of the nerve and NSD following surgery.