Treatment modalities of neurosensory deficit after lower third molar surgery: a systematic review

The Effect of Delayed Photobiomodulation Therapy on Inferior Alveolar Nerve Recovery After Third Molar Removal: A Triple-Blinded Randomized Clinical Trial

Background: Third molar removal is the primary reason for inferior alveolar nerve (IAN) damage, with 2% causing persistent neurosensory deficits. This study aimed to investigate how delayed photobiomodulation therapy affects long-lasting neurosensory disturbances. Methods: This study was conducted on patients with neurosensory disturbances lasting longer than 6 months. Patients were randomly allocated to the study and control groups, with the study group receiving a low-power diode laser (continuous wavelength of 810 nm, power of 200 mW) on 16 points (30 sec at each) for 12 sessions (2 sessions/week), while the control group received a placebo treatment by switched-off laser probe. Visual analog scale (VAS; ranging from 1 to 5), static light touch, two-point discrimination, direction discrimination, pinprick, and thermal discrimination tests were performed on each visit up to 9 months post-therapy to evaluate the recovery status. Results: Each group comprised 18 participants. The mean time since injury was 8.26 ± 2.05 and 8.38 ± 1.98 months for the control and intervention groups, respectively (p = 0.81). There was a significant improvement in the intervention group on the static light touch (p = 0.041), two-point discrimination (p = 0.028), VAS (p = 0.031), and pinprick (p = 0.014) tests on the 11th session and subsequent visits and also on direction discrimination test on the 12th session (p = 0.044) and after that. There was no significant difference in the thermal discrimination tests between the two groups (p > 0.05). Conclusion: Photobiomodulation demonstrated potential benefits in resolving persistent neurosensory deficits of the IAN, with noticeable improvements typically observed after around 35 days of treatment initiation (10 sessions).

Technical Strategies for Custom-Made Surgical Guide in Removal of Impacted Supernumerary Mandibular Premolars

ABSTRACT

The aim of this study is to evaluate the technique of surgical guide in the extraction of impacted supernumerary mandibular premolars. This case series included 5 patients. Impacted supernumerary mandibular premolars were removed through a lateral window approach using the surgical guides. The mental nerve and adjacent teeth were properly protected by our custom-made surgical guides. All cases successfully underwent the operation. An average of 5.01 ± 1.10 min was required to locate the supernumerary mandibular premolar. There were no complications involving injury to the mental nerve injury or adjacent teeth in any case. The application of custom-made surgical guides in the extraction of impacted supernumerary mandibular premolars showed an acceptable clinical outcome in this case series.

Effectiveness of low-level laser therapy on recovery from neurosensory disturbance after sagittal split ramus osteotomy: a systematic review and meta-analysis

Background

Orthognathic surgery such as bilateral sagittal split ramus osteotomy (BSSRO) for the treatment of mandibular deformities is one of the most common procedures in maxillofacial operations that may lead to neurosensory disturbance. In this study, we aimed to evaluate the effectiveness of low-level laser therapy (LLLT) on augmenting recovery of neurosensory disturbance of inferior alveolar nerve (IAN) in patients who underwent BSSRO surgery.

Methods

A comprehensive literature search was conducted by two independent authors in PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, Embase, and Google Scholar electronic databases. Besides, a manual search of all textbooks and relevant articles were conducted. Searches took place in August 2020 and were limited to published and peer-reviewed articles from 2000 to 2020. All analysis was performed using the comprehensive meta-analysis (CMA) and the STATA MP (version:16) software. The weighted mean difference (WMD) using the inverse variance method and the standard mean difference (SMD) was considered for continuous variables.

Results

Seventy-four papers were retrieved after removing duplicate studies and finally, eight studies were assessed for qualitative synthesis and five for meta-analysis. Totally, 94 patients were included in the meta-analysis. Based on the meta-analysis, it was shown that LLLT was not effective in a short interval (0 to 48 h) after surgery, but in a period of more than 1 month after surgery, the positive results of treatment can be observed strikingly. Also, LLLT side/group showed no significant difference in some aspects of neurosensory recovery such as thermal sensation compared to the placebo side/group.

Conclusions

The meta-analysis of randomized controlled trials revealed that LLLT generally improves IAN sensory disturbance caused by BSSRO. Further high-quality clinical trials with longer follow-up periods and larger sample sizes are recommended.

UC-USP collaborative exercise on photobiomodulation therapy in neurological orofacial disturbances

Background

Neurosensory peripheral disorders are one of the most common risks associated with iatrogenic and/or post-traumatic injuries. It is often related to disability. Photobiomodulation therapy (PBMT) is a nonsurgical and safe procedure which can accelerate and improve the regeneration of injured biological tissue. This study aims to analyze the impact of PBMT, in the quality of life and impairment of individuals with orofacial neurological peripheral disturbance.

Material and Methods

A retrospective analysis in the database of the dental traumatology clinic of the Hospital Centre of the University of Coimbra/Faculty of Medicine of the University of Coimbra was performed.5 out of 50 individuals were selected, according to the selection criteria. The neurosensory activity was assessed by a pinprick nociceptive test and the EQ-5D-5L self-report questionnaire was used to analyse the quality of life. The study was performed in two phases:1) inactive laser or placebo phase, for one month and 2) active laser or treatment phase. A diode low-level laser device (SIROLaserBlue;Sirona,Germany) was used, according to our protocol. A collaborative protocol in the PBMT influence in individuals with neurosensory peripheral disturbances was studied.

Results

There was no improvement in the neurosensory activity nor in the quality of life, in the placebo phase. After the treatment phase, the EQ-5D-5L final results reported no problems in all of the five dimensions, except for anxiety/depression in individuals with long-standing neurosensory peripheral disturbances. The EQ-VAS scores increased in all the individuals.

Conclusions

Our results supported the improvement of quality of life and impairment reduction in the individuals submitted to PBMT.

Key words:Low-level light therapy, peripheral nerve injuries, sensation disorders, quality of life, forensic medicine.

Clinical outcomes of lingual nerve repair

Lingual nerve injury, a well-described complication of third molar removal, may result in permanent lingual sensory deficit leading to symptoms including lost or altered sensation, inadvertent tongue biting, and the development of unpleasant neuropathic pain, with consequent impaired quality of life. We analysed outcomes of a prospective case series to determine whether direct anastomosis of the lingual nerve results in improved sensory recovery and reduced neuropathic pain, and whether delayed surgery is worthwhile. In 114 patients who underwent nerve repair at our nerve injury clinic following damage sustained during mandibular third molar removal, sensory deficit was assessed before and after surgery using a questionnaire and visual analogue scales (VAS) to assess pain, tingling, and discomfort. Neurosensory tests were utilised to evaluate light touch, pin-prick, and two-point discrimination thresholds. Subjectively, 94% patients felt their sensation had improved following nerve repair, with significant reductions in the incidence of tongue biting (p<0.0001), impaired speech (p<0.0001), and neuropathic pain (p=0.0017). Quantitative neurosensory data showed highly significant improvements in light touch, pin-prick, and two-point discrimination (all p<0.0001), and VAS scores for pain (p=0.0145), tingling (p<0.0025), and discomfort (p<0.0001) were significantly reduced. Patients with high levels of pain preoperatively (VAS>40) showed highly significant reductions in pain (p<0.0001). No correlation was found between surgical outcome and patient's age or delay until surgery. Lingual nerve repair results in good sensory outcomes and significant improvements in the incidence and degree of neuropathic pain, even when delayed.

Management and prevention of third molar surgery-related trigeminal nerve injury: time for a rethink

Trigeminal nerve injury as a consequence of lower third molar surgery is a notorious complication and may affect the patient in long term. Inferior alveolar nerve (IAN) and lingual nerve (LN) injury result in different degree of neurosensory deficit and also other neurological symptoms. The long term effects may include persistent sensory loss, chronic pain and depression. It is crucial to understand the pathophysiology of the nerve injury from lower third molar surgery. Surgery remains the most promising treatment in moderate-to-severe nerve injuries. There are limitations in the current treatment methods and full recovery is not commonly achievable. It is better to prevent nerve injury than to treat with unpredictable results. Coronectomy has been proved to be effective in reducing IAN injury and carries minimal long-term morbidity. New technologies, like the roles of erythropoietin and stem cell therapy, are being investigated for neuroprotection and neural regeneration. Breakthroughs in basic and translational research are required to improve the clinical outcomes of the current treatment modalities of third molar surgery-related nerve injury.

Photobiomodulation Therapy in Oral Medicine: A Guide for the Practitioner with Focus on New Possible Protocols

Photobiomodulation (PBM) is the term to define the wide range of laser applications using low-energy densities and based on photochemical mechanisms where the energy is transferred to the intracellular mitochondrial chromophores and respiratory chain components. In literature, a great number of works are reported showing the advantages of PBM use in many oral diseases such as recurrent aphthous stomatitis, herpes infections, mucositis, and burning mouth syndrome. Different factors may explain the increasing reported use of PBM in oral medicine: the absence of side effects, the possibility of safely treating compromised patients such as oncologic patients, the possibility of a noninvasive approach not associated with pain or discomfort, and the possibility of performing short sessions. The review's aim is to describe the possible applications of PBM in oral medicine, giving practitioners simple guide for practice together with the information of a new treatment possibility "at home" performed by the patient himself under supervision.

Comparative effects of photobiomodulation therapy at wavelengths of 660 and 808 nm on regeneration of inferior alveolar nerve in rats following crush injury

The aim of the present study was to investigate the therapeutic effects of 660-nm and 880-nm photobiomodulation therapy (PBMT) following inferior alveolar nerve (IAN) crush injury. Following the nerve crush injuries of IAN, 36 Wistar rats were randomly divided into three groups as follows: (1) control, (2) 660-nm PBMT, and (3) 808-nm PBMT (GaAlAs laser, 100 J/cm², 70 mW, 0.028-cm² beam). PBMT was started immediately after surgery and performed once every 3 days during the postoperative period. At the end of the 30-day treatment period, histopathological and histomorphometric evaluations of tissue sections were made under a light and electron microscope. The ratio of the inner axonal diameter to the total outer axonal diameter (g-ratio) and the number of axons per square micrometer were evaluated. In the 808-nm PBMT group, the number of nerve fibers with suboptimal g-ratio ranges of 0-0.49 (p < 0.001) is significantly lower than expected, which indicates better rate of myelinization in the 808-nm PBMT group. The number of axons per square micrometer was significantly higher in the 808-nm PBMT group when compared with the control (p < 0.001) and 660-nm PBMT group (p = 0.010). The data and the histopathological investigations suggest that the PBMT with the 808-nm wavelength along with its settings was able to enhance IAN regeneration after nerve crush injury.

A Novel Orthodontic Extraction Method for Removal of Impacted Mandibular Third Molars in Close Proximity to Inferior Alveolar Nerve

PURPOSE

The present study has proposed a novel orthodontic extraction method with a removable appliance to avoid inferior alveolar nerve (IAN) injury during impacted mandibular third molar removal.

PATIENTS AND METHODS

In the present study, 16 patients were enrolled and divided into 2 groups per patient choice. In the orthodontic extraction group (n = 8), a removable appliance was first applied to move the root tips away from the IAN, and the tooth was subsequently removed. In the traditional extraction group (n = 8), each patient had the tooth removed immediately by the same surgeon.

RESULTS

All teeth were extracted successfully. All 8 patients in the orthodontic extraction group had had their impacted mandibular third molar removed without IAN injury after surgery. In contrast, 4 patients in the traditional extraction group had experienced transient IAN injury, and the symptoms persisted for 2 to 8 weeks. None of the patients experienced permanent IAN damage.

CONCLUSIONS

Orthodontic extraction with a removable appliance to separate the IAN and impacted mandibular third molar could be a good alternative treatment option to avoid IAN injury in high-risk cases.

Treatment modalities and risk factors associated with refractory neurosensory disturbances of the inferior alveolar nerve following oral surgery: a multicentre retrospective study

Little research has been conducted into hypoesthesia, and no studies have elucidated the risk factors for refractory hypoesthesia and compared treatment modalities. The purpose of this multicentre retrospective cohort study was to investigate the relationships between various risk factors, treatment modalities, and refractory hypoesthesia. Risk factors for refractory hypoesthesia after oral surgery were evaluated using univariate and multivariate analysis. To minimize the selection bias associated with a retrospective data analysis, a propensity score analysis was performed between the medication and non-medication groups (65 sites in each group). Moderate or severe hypoesthesia (odds ratio 13.42) and no or late administration of ATP/vitamin B12 (odds ratio 2.28) were significantly associated with refractory hypoesthesia. In the propensity score analysis, the incidence rate of refractory hypoesthesia in the medication group was lower than that in the non-medication group (P<0.001). This study demonstrated the multivariate relationships between various risk factors, treatment modalities, and refractory hypoesthesia. Moderate or severe hypoesthesia and no or late administration of ATP/vitamin B12 were significantly associated with refractory hypoesthesia. Therefore, clinicians should consider these risk factors and initiate early oral administration of ATP/vitamin B12 in cases of hypoesthesia.

Iatrogenic displacement of high-speed bur during third molar removal

Surgical removal of impacted mandibular third molar is a routine procedure in oral surgery. Various iatrogenic complications related to the procedure has been discussed well in the literatures before. Some of these complications are related to the wrong usage of instruments and techniques. Here we discuss a rare complication on a 42-year-old male, related to the use of high-speed handpiece drill in mandibular third molar removal in a general dental office setting. He was referred when a high speed tungsten carbide bur was accidentally broken and displaced into the mandibular bone during surgical procedure. It is not common to use a high-speed handpiece in impacted third molar removal. This iatrogenic complication could have been totally avoided with the use of proper equipment and technique; therefore raising awareness regarding wrong usage of instrument is vital to avoid similar incidents in the future.

Is Low-Level Laser Therapy Effective for Treatment of Neurosensory Deficits Arising From Sagittal Split Ramus Osteotomy?

PURPOSE

This study investigated the effectiveness of low-level laser therapy (LLLT) for treating neurosensory impairment after bilateral sagittal split osteotomy (BSSO).

MATERIALS AND METHODS

This randomized, double-blinded, split-mouth trial included patients requiring BSSO. After surgery, 1 side of each patient was randomly assigned to laser therapy and the other side served as the control. At 24, 48, and 72 hours after surgery, LLLT was accomplished by intraoral application of a 660-nm laser around the surgical site (200 mW, 10 seconds, 2 J, 1.5 J/cm²) followed by extraoral irradiation by an 810-nm laser (200 mW, 10 seconds, 2 J, 7 J/cm²) along the distribution of the inferior alveolar nerve. Subsequently, extraoral irradiation was repeated 2 times per week for 3 weeks along the path of the inferior alveolar nerve, lower lip, and chin. On the control side, the treatment was similar to the laser side but with laser simulation. The main outcome was assessing nerve damage by a "2-point discrimination test" before and up to 60 days after surgery.

RESULTS

The sample consisted of 16 patients. No significant difference was found between the laser and control sides before and after surgery and on postoperative days 15 and 30 (P > .05). The 2-point discrimination distance was significantly shorter on the laser side than on the control side on postoperative days 45 and 60 (P < .05).

CONCLUSION

LLLT was effective in the treatment of neurosensory disturbances arising from BSSO. Therefore, LLLT can be recommended to accelerate the recovery of sensory aberrations in patients undergoing BSSO.

Temporal Evaluation of Neurosensory Complications After Mandibular Third Molar Extraction: Current Problems for Diagnosis and Treatment

Objective:

This retrospective study aimed to report the incidence of neurosensory complications after third molar extraction and also to identify current problems and discuss appropriate management of these complications.

Method:

Patients who underwent extraction of deeply impacted mandibular third molars under general anesthesia were included. The following epidemiological data were retrospectively gathered from medical charts: type of neurosensory complication, treatment for complication, and outcome.

Results:

A total 369 mandibular third molars were extracted in 210 patients under general anesthesia during this study period. Thirty-one of the 369 teeth (8.4%) in 31 patients had neurosensory complications during the first postoperative week resulting from inferior alveolar nerve damage. Neurosensory complications lasting from 1 to 3 months postoperatively included 17 cases of hypoesthesia and 8 of dysesthesia in 19 patients. Five cases of hypoesthesia and 4 of dysesthesia in 5 patients persisted over 1 year postoperatively. Sixteen of 369 teeth (4.3%) in 16 patients had persistent neurosensory complications after third molar extraction under general anesthesia. Stellate ganglion block was performed in 4 patients. Early initiation of stellate ganglion block (within 2 weeks postoperatively) produced better outcomes than late stellate ganglion block (over 6 months postoperatively).

Conclusion:

Refractory neurosensory complications after third molar extraction often combine both hypoesthesia and dysesthesia. Current problems in diagnosis and treatment included delayed detection of dysesthesia and the lack of uniform timing of stellate ganglion block. In the future, routinely inquiring about dysesthesia and promptly providing affected patients with information about stellate ganglion block might produce better outcomes.

How Far Have We Come in the Field of Nerve Regeneration After Trigeminal Nerve Injury?

Patients suffering from nerve injury with sensory disturbances or orofacial pain have greatly reduced quality of life, and it is a big cost for the society. Abnormal sensations caused by trigeminal nerve injury often become chronic, severely debilitating, and extremely difficult to treat. In general, non-invasive treatment such as drug treatment has been insufficient, and there are currently few available effective treatments. Surgical interventions such as end-to-end connection or nerve grafting have disadvantages such as donor site morbidity or formation of neuroma. There is need for optimizing the technique for nerve repair, especially for the trigeminal nerve system, which has so far not yet been well explored. Recently, tissue engineering using biodegradable synthetic material and cell-based therapies represents a promising approach to nerve repair and it has been reported that mesenchymal stem cell (MSC) has an anti-inflammatory effect and seems to play an important role in nerve healing and regeneration.

Longitudinal Treatment Outcomes of Microsurgical Treatment of Neurosensory Deficit after Lower Third Molar Surgery: A Prospective Case Series

Objective

To prospectively evaluate the longitudinal subjective and objective outcomes of the microsurgical treatment of lingual nerve (LN) and inferior alveolar nerve (IAN) injury after third molar surgery.

Materials and Methods

A 1-year longitudinal observational study was conducted on patients who received LN or IAN repair after third molar surgery-induced nerve injury. Subjective assessments (“numbness”, “hyperaesthesia”, “pain”, “taste disturbance”, “speech” and “social life impact”) and objective assessments (light touch threshold, two-point discrimination, pain threshold, and taste discrimination) were recorded.

Results

12 patients (10 females) with 10 LN and 2 IAN repairs were recruited. The subjective outcomes at post-operative 12 months for LN and IAN repair were improved. “Pain” and “hyperaesthesia” were most drastically improved. Light touch threshold improved from 44.7g to 1.2g for LN repair and 2g to 0.5g for IAN repair.

Conclusion

Microsurgical treatment of moderate to severe LN injury after lower third molar surgery offered significant subjective and objective sensory improvements. 100% FSR was achieved at post-operative 6 months.

Efficacy of a single dose of low-level laser therapy in reducing pain, swelling, and trismus following third molar extraction surgery

The clinical efficacy of low-level laser therapy (LLLT) for the reduction of pain, swelling, and trismus following the surgical extraction of third molars was evaluated. Mandibular third molars, with similar radiographic positions on two distinct sections, were extracted from 22 patients. Immediately after extraction from the randomly selected right or left side, LLLT was applied (study group). The same extraction procedure was performed 21 days later on the other third molar, without the application of LLLT (control group). LLLT was applied at 10 points: four intraoral in close proximity to the socket and six extraoral along the masseter muscle. Pain intensity was assessed using a visual analogue scale, swelling was measured as the distance from the tragus to the median base of the mentum, and trismus was assessed by the extent of mouth opening. Data were collected at four time points: before surgery, immediately after surgery, 48h postoperatively, and 7 days postoperatively. Compared with the control group, the study group showed significant reductions in pain, swelling, and trismus at 48h and 7 days postoperatively. In conclusion, a single dose of LLLT was effective at reducing the postoperative discomforts (pain, swelling, and trismus) associated with third molar extraction surgery.

Wound Dehiscence after Wisdom Tooth Removal in Mandibular Mesioangular Class IB Impactions: Triangular Transposition Flap versus Envelope Flap

Background and aims. Wound dehiscence after lower third molar surgery extends the postoperative treatment period and may cause long-standing pain. The aim of this study was to compare wound dehiscence after removal of wisdom teeth in the most prevalent mandibular impaction (mesioangular class IB) by two different soft tissue flap designs.

Materials and methods. Partially-erupted mandibular third molars with mesioangular class IB impaction (Pell and Gregory classification) were selected. Split mouth technique was used to compare the two flap designs (envelope vs. triangular transposition flap—TTF). The patients were recalled one week and a month later and rechecked for dehiscence, infection, and dry socket formation.

Results. There were no cases of infection in either group. However, three cases of dry socket in the envelope group and four in the TTF group were recorded. In the envelope group, dehiscence occurred in 43% of cases during the first week, with 67% of cases being a large dehiscence (diameters of more than 5 mm). Extra appointments (those requested by the patient exclusively related to the problem of the hole distal to the second molar) were scheduled in 10% of cases in the envelope group. In the TTF group, dehiscence occurred during the first week for the same impaction in 19% of cases with large dehiscence cases occurring in 65% of cases and extra appointment rate at 4.1%.

Conclusion. According to theresults in the evaluated operation, TTF may prevent postoperative wound dehiscence more probably than the envelope flap.

Unusual Occurrence of Tongue Sensorial Disorder after Conservative Surgical Treatment of Lymphoepithelial Cyst

Lymphoepithelial cyst is a rare lesion of the oral cavity, with the mouth floor being the most common site of occurrence. The therapeutic approach of choice is the surgical treatment, which has rare cases of postoperative complications. The aim of this study is to report the case of a 53-year-old patient who came to Dental Service in the Federal University of Ceará complaining of a small nodular lesion (0.5 cm) located in the ventral tongue. Excisional biopsy was performed and the surgical specimen was submitted for anatomopathological analysis, which found that there was an oral lymphoepithelial cyst. The patient returned after seven days for suture removal and reported loss of sensitivity around the ventral tongue. We prescribed Citoneurin for ten days; however, there was not any significant improvement of the sensitivity. Low frequency laser therapy sessions were applied. The only postoperative symptom was dysesthesia, where there is only a sensitivity decrease. Currently, the patient has a postoperative period of 1 year without recurrence of the lesion. Although previous reports have no described tongue sensorineural disorders associated with this lesion, the occurrence of this event may be related to an unexpected anatomical variation of the lingual nerve.

Implant-related nerve injuries

Injuries to branches of the trigeminal nerves are a known complication during dental implant placement. These injuries tend to be more severe than those experienced during other dentoalveolar procedures. This article reviews the types of nerve injuries and areas and situations of which clinicians should be cognizant when placing dental implants. Strategies to avoid injuries, and a management algorithm for suspected nerve injuries, are also discussed.

Lingual Nerve Repair: To Graft or Not to Graft?

PURPOSE

Since no studies have compared direct and graft repair of the lingual nerve, we examined the subjective and objective outcomes of lingual nerve repair by direct epineurial repair and indirect graft repair, assessed the effect of other confounding variables, and compared the outcomes of autograft and allograft repairs.

PATIENTS AND METHODS

All patients who had undergone microneurosurgical repair of the lingual nerve from 2000 to 2012 by 1 surgeon (M.M.) were asked to complete an online questionnaire regarding their current neurosensory status at least 2 years after nerve repair. A direct comparison was made between patients who had undergone direct epineurial repair and those who had undergone interpositional nerve graft repair. Student's t test and χ(2) test were used to determine whether a significant difference existed in the success between the 2 techniques and whether age, gender, race, delay from injury to repair, or degree of initial nerve deficit influenced the success of nerve repair.

RESULTS

Of the 72 patients identified, 43, who had undergone 47 nerve repairs (18 direct, 29 indirect graft repairs [4 bilateral]; 28 female and 19 male patients; mean age 28.3 years), were interviewed. The objective results of functional sensory recovery, defined by a Medical Research Council Scale grade of S3, S3+, or S4, was 89% for the graft repairs and 85% for the direct repairs (P = .01). The subjective patient satisfaction score (0 to 10 scale) was 8.9 for the graft repairs and 8.1 for the direct repairs (P = .02). The autograft and allograft repairs performed comparably, and the other variables (ie, age, gender, race, delay from injury to nerve repair, gap length, and initial Sunderland grade injury) were not found to be significant (P > .05).

CONCLUSION

Graft repair of the lingual nerve provides superior long-term (>2 years) objective and subjective outcomes compared with direct repair. This might be because of the lack of tension at the repair site, more freedom with nerve stump preparation, and the addition of neurotropic and neurotrophic factors from the donor nerve graft at the site of injury to augment neurosensory recovery.

Assessment of the shape of the inferior alveolar canal as a marker for increased risk of injury to the inferior alveolar nerve at third molar surgery: a prospective study

PURPOSE

Morphologic evaluation of computed tomographic images is an important assessment tool before surgical removal of the lower third molar (LM3). The aim of this study was to ascertain whether the shape of the inferior alveolar canal (IAC) is a reliable predictor for inferior alveolar nerve (IAN) injury during M3 surgery.

MATERIALS AND METHODS

This prospective study assessed samples with a high risk of IAN injury during M3 surgery based on orthopantomographic examination. The predictor variables were demographic factors (patient's age and gender), anatomic factors (angulation of the tooth), and radiographic factors (cortication status, buccolingual position, shape of the IAC, number of roots, and root shape). The outcome variable was IAN injury. The relation between predictor and outcome variables was analyzed using the Fisher exact test and a logistic regression model.

RESULTS

One hundred sixty-nine LM3s (115 patients) were analyzed. IAN injury was observed in 12 of 115 patients and 13 of 169 LM3s (7.7%). All 13 cases with IAN injury exhibited absence of cortication. A dumb-bell-shaped IAC was considered a useful predictor for IAN injury (sensitivity, 69.2%; specificity, 84.6%). In cases with absence of cortication, logistic regression analysis indicated that a dumb-bell-shaped IAC was closely related to IAN injury (P = .005).

CONCLUSION

The cortication status and shape of the IAC are reliable predictors for IAN injury at M3 surgery. Cases exhibiting absence of cortication and a dumb-bell-shaped IAC should be recognized as presenting a high risk of IAN injury at M3 surgery.

Lower-level laser therapy improves neurosensory disorders resulting from bilateral mandibular sagittal split osteotomy: a randomized crossover clinical trial

Bilateral sagittal split osteotomy (BSSO) is a technique commonly used to correct mandibular disproportion but many patients experience hypoaesthesia of the inferior alveolar nerve (IAN). The purpose of this study was to verify the effectiveness of using a low-level laser therapy protocol after BSSO. The 10 patients in our study, who underwent BSSO with Le Fort I osteotomy and had low-level laser therapy on one side of the jaw, were evaluated over a period of 60 days. The data for the treated and non-treated sides were compared post-operatively. At 15, 30 and 60 days after surgery, when sensitivity was recovered on both sides. On the treated side, recovery was faster and was almost complete at the time of the last evaluation. We suggest that this lower-level laser therapy protocol can improve tissue response and accelerate the recovery of neurosensory disorders following BSSO. (NCT01530100).

Modified and grafted coronectomy: a new technique and a case report with two-year followup

Purpose. A standard coronectomy (intentional partial odontectomy) is recommended for mandibular third molar (MTM) extraction cases with a high risk of inferior alveolar nerve injury (IANI). However, complications such as inadvertent intraoperative root removal, post-op root migration, second molar (MSM) periodontal defects and others do exist. This report presents a new technique, the Modified and Grafted Coronectomy (MGC), describes the measures to prevent or minimize the known drawbacks of the standard coronectomy, and reviews the literature for comparison with three other IANI-prevention techniques. Materials and Methods. MGC was performed on two MTMs with nerve involvement and severe periodontal pockets on the distal of MSM. Modifications were: stabilizing the root stump to prevent intraoperative movement, creation of a large intrabony space for bone graft material, and grafting for periodontal healing while minimizing the possibility of post-op root migration. Results. Excellent overall periodontal improvement, with probing depths reduced to 3-4 mm. Panoramic radiograph displayed remarkable bone regeneration. No residual root migration was evident at the two year follow up. Conclusion. MGC may be a good alternative, especially in cases with periodontal defects on the distal of MSM. It may also help to minimize inadvertent intraoperative root removal and postoperative root migration.