Efficacy of Photobiomodulation on Neurosensory Recovery in Patients with Inferior Alveolar Nerve Injury Due to Third Molar Extraction and Implant Surgery: a Systematic Review

The present systematic review aimed to assess the efficacy of photobiomodulation (PBM) therapy on neurosensory recovery of patients with inferior alveolar nerve injury following third molar surgery or dental implant placement. An electronic search was carried out in Scopus, Embase, Medline, PubMed, Web of Science, Cochrane Library, and Google Scholar databases. Among 1,122 identified papers, seven articles (three RCTs, one observational study, and three case series) met the inclusion criteria. <br />Results: Time lapse from nerve injury to the onset of PBM therapy varied widely from 2days to 4years. The number of patients in each study ranged between 4 and 74. In the majority of the studies, PBM was done using a diode laser at wavelengths ?in the range of 808 to 830nm with power of 5 to 500mW and radiation dose of 3 to 244 J/cm2. Two out of three RCTs found significant neurosensory recovery in the patients who received PBM therapy compared to the controls. The observational study and all case series reported significant improvement in the neurosensory status following PBM therapy. The degree of neurosensory recovery was found to be greater in younger patients and those who received the treatment within 6months following the injury. <br />Conclusions: Due to the limited number of well-designed RCTs and small number of patients in each study, it is not possible to make a clear conclusion about the efficacy of PBM therapy on neurosensory recovery in patients with inferior alveolar nerve injury following third molar or implant procedures. Considering the possibility of spontaneous inferior alveolar nerve recovery during this period, the conclusion based on the studies with no control group should be interpreted with caution. (Quintessence Int 2021;52:140-153; doi:10.3290/j.qi.a45430).

The aim of this META-analysis was to evaluate the efficacy of photobiomodulation (PBM) therapy in the treatment of inferior alveolar nerve (IAN) injury due to orthognathic surgeries, extraction of impacted third molars and mandibular fractures. A electric search was conducted by a combination of manual search and four electric databases including Pubmed, Embase, Cochrane library and Web of Science, with no limitation on language and publication date. Gray literature was searched in ClinicalTrials.gov and googlescholar. All retrieved articles were imported into ENDNOTE software (version X9) and screened by two independent reviewers. All analysis was performed using the REVMAN software (version 5.3). Finally, 15 randomized controlled trials met the inclusion criteria for qualitative analysis and 14 for META-analysis from 219 articles. The results showed that PBM therapy had no effect on nerve injury in a short period of time (0-48h, 14 days), but had significant effect over 30 days. However, the effect of photobiomodulation therapy on thermal discrimination was still controversial, most authors supported no significant improvement. By calculating the effective rate of PBM, it was found that there was no significant difference in the onset time of treatment, whether within or over 6 months. The results of this META-analysis show that PBM therapy is effective in the treatment of IAN injures no matter it begins early or later. However, due to the limited number of well-designed RCTs and small number of patients in each study, it would be necessary to conduct randomized controlled trials with large sample size, long follow-up time and more standardized treatment and evaluation methods in the future to provide more accurate and clinically meaningful results.

Introduction: Inferior alveolar nerve (IAN) injury is among the most common complications associated with orthognathic surgery. Managing these injuries poses significant challenges due to the lack of a standardized treatment protocol. This study aimed to systematically review the literature on the efficacy of blood products and photobiomodulation (PBM) therapy for neurosensory recovery in patients with IAN injuries after orthognathic surgery. Methods: This systematic review involved a comprehensive search of Scopus, Embase, and PubMed databases, as well as the initial 100 search results from Google Scholar, to identify relevant articles published between 2015 and 2024. The articles were selected using defined eligibility criteria. Results: The research paper reviewed 170 articles, ultimately including 14 studies that focused on IAN injury related to surgical procedures such as genioplasty, sagittal split mandibular ramus osteotomy (SSRO), and bilateral sagittal split osteotomy (BSSO). Among these studies, five assessed the effectiveness of various blood products-specifically platelet-rich fibrin (PRF), leukocyte-rich PRF (L-PRF), advanced PRF (A-PRF), and concentrated growth factor (CGF)-all of which were found to alleviate hypoesthesia. Nine studies evaluated the efficacy of PBM, primarily utilizing wavelengths of 810 and 808 nm over 5 to 10 sessions. PBM also successfully enhanced the recovery of IAN. Moreover, one article highlighted the synergistic effect of using L-PRF in conjunction with PBM. Conclusion: It appears that neurosensory recovery following IAN injury due to orthognathic surgery may be enhanced by blood-derived products such as PRF, CGF, A-PRF, and L-PRF, which release growth factors that facilitate tissue repair. Additionally, PBM further supports recovery by reducing inflammation in the initial weeks and stimulating cellular metabolism to promote regeneration in the subsequent weeks.

Extraction of impacted mandibular third molars (IMTMs) is the most common surgery performed in the Department of Oral and Maxillofacial Surgery. Inferior alveolar nerve (IAN) injury is a rare but severe complication, and the risk is significantly higher in cases of IMTM near the inferior alveolar canal (IAC). The existing surgical method to extract such IMTMs is either not safe enough or is time-consuming. A better surgical design is needed. From August 2019 to June 2022, 23 patients underwent IMTM extraction by Dr. Zhao at Nanjing Stomatological Hospital, Affiliated Hospital of Medical School, Nanjing University, and were found to have IMTMs in close proximity to the IAC. Due to high IAN injury risk, these patients underwent coronectomy-miniscrew traction to extract their IMTMs. The time between coronectomy-miniscrew insertion and complete removal of the IMTM was 32.65 ± 2.110days, which was significantly shorter than that of traditional orthodontic traction. Two-point discrimination testing revealed no IAN injury, and no injury was reported by patients during follow-up. Other complications, such as severe swelling, severe bleeding, dry socket, and limited mouth opening, were not observed. Postoperative pain levels were not significantly higher in the coronectomy-miniscrew traction group than in the traditional IMTM extraction group. For IMTMs that are in close proximity to the IAC and must be extracted, coronectomy-miniscrew traction is a novel approach to minimize the risk of IAN injury in a less time-consuming way with a lower possibility of complications.

Inferior alveolar nerve (IAN) injury is one of the most serious complications after extraction of impacted lower third molars. Photobiomodulation (PBM) therapy has been noted to reduce pain and inflammation while promoting tissue healing. This study examined the efficacy of PBM therapy tested in a case series of patients with postoperative IAN injury. 20 patients with post-extraction IAN injury were involved in this study and divided into two groups. In the study group, PBM therapy (808-nm laser, 16 mW, 3 J/cm2) was used every other day for 2 weeks solely on post-extraction sockets in 10 patients diagnosed with IAN injury. In the control group, mecobalamine was prescribed to 10 patients with IAN injury. Objective and subjective recovery of IAN paresthesia was evaluated using clinical neurosensory testing and visual analog score. All patients showed improvement in both objective and subjective examination. Notably, the visual analog score was significantly improved after PBM treatment compared to the mecobalamine treatment (p < 0.05). PBM therapy with 808-nm laser appears to be an effective approach to manage paresthesia post-IAN injury following impacted third molar surgery. Given the limited sample size in this study, large-scale, placebo-controlled, multi-center randomized controlled trials are needed for further validation of this innovative treatment.

Retrospective evaluation of sensory neuropathies after extraction of mandibular third molars with confirmed “high-risk” features on cone beam computed topography scans

Assessment of the Relationship Between Impacted Mandibular Third Molars and Inferior Alveolar Nerve With Dental 3-Dimensional Computed Tomography

Introduction: Surgical removal of mandibular third molars is one of the most frequent clinical tasks conducted by dental surgeons. This surgery is associated with the possibility of delayed and complicated soft-tissue and hard-tissue healing. Local incorporation of bioactive materials (such as growth factors and blood products) has been attempted to promote faster and better healing. Platelet-rich Fibrin (PRF) is the latest development among blood-derived products and is widely used to enhance hard and soft-tissue healing. Aim: To estimate the effect of PRF on soft-tissue and hardtissue healing following the surgical extraction of mandibular third molars. Materials and Methods: This prospective interventional study was carried out in the Department of Oral and Maxillofacial Surgery at Guru Nanak Institute of Dental Science and Research, Kolkata, West Bengal, India. The study was conducted between May 2022 and January 2024. Patients who required extraction of impacted mandibular third molars were divided into two groups (group I and group II) by alternate selection methods. PRF was placed in the empty sockets of group I patients following the surgical extraction of the third molar, while the sockets of group II patients were allowed to heal without PRF. Soft-tissue healing evaluation was performed using the parameters of the healing index on the 3rd, 7th, 14th, and 28th post-extraction days by two blind observers. Hard-tissue healing was evaluated using the Cone Beam Computed Tomography (CBCT) findings on the 1st month and 3rd month postoperatively. Changes in empty socket volume, Bone Density Units (BDU) of the new bone, and the type of new bone were analysed. Statistical analysis was carried out using IBM Statistical Package for Social Sciences (SPSS) Statistics for Windows, version 26.0 (Armonk, NY: IBM Corp). A p-value of &lt;0.05 was considered significant. Results: Twenty-six patients were included in the final analysis. They were equally divided into the interventional group (group I, with PRF) and the control group (group II, without PRF). The demographic data and difficulty index of group I were similar to those of group II. The corrected Chi-square test of independence was performed to compare soft-tissue healing. A highly significant association was found on the 3rd postoperative day (p-value=0.03), 14th postoperative day (p-value=0.013), and 28th postoperative day (p-value=0.002), indicating that group I consistently demonstrated improved healing compared to group II. The volume of the empty socket of the extracted third molar was measured using CBCT on the 1st and 3rd postoperative months. In both groups, the volume reduced significantly, but the reduction was more pronounced in group I than in group II (p-value &lt;0.0001). The quality of bone formation (measured by BDUs) was significantly better in group I than in group II (p-value=0.043). However, the type of bone formation was similar for both groups. Conclusion: PRF appears to be beneficial and effective in promoting postoperative soft-tissue and hard-tissue healing following the surgical extraction of mandibular third molars.

Delayed Paresthesia of Inferior Alveolar Nerve After Extraction of Mandibular Third Molar: Case Report and Possible Etiology

Introduction: Inferior alveolar nerve (IAN) injury is a serious complication during intraoral surgeries. We aimed to evaluate the outcome of photobiomodulation (PBM) therapy in patients with IAN injury associated with third molar or implant procedures. Methods: Eight patients with an alteration of sensory function of the IAN after third molar or implant surgeries were enrolled in this case series study. The patients received 10 sessions of PBM therapy (810 nm diode laser, 200 mW, 10 J/cm2 per point, three times a week). Pinprick (PP) and visual analogue scale (VAS) neurosensory tests were recorded at each treatment session and 14 days after the last treatment. The association between explanatory variables and the outcome of interest was analyzed using generalized estimating equations. Results: The median percentage change of outcomes from the first to the last visit was as follows: VAS score: +125.00% (range: 50.00 to 166.67); PP score: +350% (range: 150 to 800). The duration of paresthesia was inversely correlated with changes in VAS and PP scores. No significant association was found between patients' gender or age and changes in VAS and PP scores. Conclusion: Considering the limitations of this study, PBM with the parameters used in this study presented positive effects on neurosensory recovery in patients suffering from IAN injury associated with routine intraoral procedures. Patients with shorter duration of paresthesia tended to respond more favorably to PBM therapy.

This study sought toexplore the manifestations of clinical symptoms and identify the risk factors linked to inferior alveolar nerve injury (IANI) in the context of mandibular third molar extraction. In this study, 172 patients admitted to our hospital for mandibular third molar extraction from June 2021 to December 2022 were selected for the study, and the clinical data of the participants were retrospectively analyzed, and the risk factors of IANI associated with mandibular third molar extraction were analyzed by uni/multi-factor logisitic regression. Noticeable distinctions were noted between the groups with and without injuries in relation to age, time of surgery, number of broken roots, angle of blockage, CEJ (cementoenamel junction) distance, curved roots of the molar, clarity of the upper and lower walls of the nerve canal, and Pell & Gregory classification. Logistic regression analysis showed that age, time of surgery, number of broken roots, angle of blockage (40°-70°), CEJ distance (10-12 mm, >12 mm), and curved roots of the molar were independent risk factors for IANI. Multi-factor logistic regression analysis further confirmed that age, number of broken roots, angle of blockage (40°-70°), CEJ distance (10-12 mm, >12 mm), and curved roots of the molar were associated with IANI. Alveolar nerve injury manifests as hyperalgesia or absence of sensation, numbness and abnormal pain in the lower lip. Factors influencing IANI associated with mandibular third molar extraction were age, number of broken roots, angle of blockage (40°-70°), CEJ distance (10-12 mm, >12 mm), and curved roots of the molar.

Oral paresthesia occurs when one of the nerves in the region is injured, usually the inferior alveolar and/or lingual nerve, after dental procedures such as the extraction of lower third molars. The objective of this study was to describe the case of a patient who received photobiomodulation (PBM) therapy for paresthesia of the inferior alveolar nerve (IAN) caused by the extraction of mandibular third molars. The protocol used involved a super-pulsed diode laser with dual wavelengths of 810 nm and 980 nm, 1 W, 60 seconds, 12.15 J/cm², with a spot size of 25 mm in the extraoral area. In the intraoral region, 0.3 W, 60 seconds, 46.77 J/cm², with a 7 mm tip, was applied. Before starting each PBM session, mapping of the area was performed to delineate the regions with paresthesia, and the degree of sensitivity was evaluated using a visual analog scale (VAS). On the first day, before the first laser therapy session, the VAS assessment was 7, indicating partial loss of sensitivity. After 48 hours and before the second PBM session, the patient reported a slight tingling sensation and substantial improvement in chin sensitivity, with a VAS score of 4.5. After nine sessions, the patient reported recovery of sensitivity in all affected regions (VAS = 0), with positive and normal responses to touch with a dental explorer. Within the parameters established for this clinical case, our results suggest that PBM therapy may improve the loss of sensation observed in IAN paresthesia following injury or surgical trauma.

The aim of this study was to evaluate the predictive value of panoramic radiography on inferior alveolar nerve (IAN) injury after extraction of the mandibular third molar. Relevant studies up to 1 June 2014 that discussed the association of panoramic radiography signs and post-mandibular third molar extraction IAN injury were systematically retrieved from the databases of PubMed, Embase, Springerlink, Web of Science and Cochrane library. The effect size of pooled sensitivity, specificity, positive likelihood ratios (PLR), negative likelihood ratios (NLR) and diagnostic odds ratio (DOR) with their 95% confidence intervals (CI) were statistically analysed with Meta-disc 1.4 software. Nine articles were included in this meta-analysis. The pooled estimates of sensitivity and specificity were 0.56 (95% CI: 0.50-0.61) and 0.86 (95% CI: 0.84-0.87), respectively. The overall PLR was 3.46 (95% CI: 2.02-5.92) and overall NLR was 0.58 (95% CI: 0.45-0.73). The pooled estimate of DOR was 6.49 (95% CI: 2.92-14.44). The area under the summary receiver operating characteristic curve was 0.7143±0.0604. The meta-analysis indicated that interpretation of panoramic radiography based on darkening of the root had a high specificity in predicting IAN injury after mandibular third molar extraction. However, the ability of this panoramic radiography marker to detect true positive IAN injury was not satisfactory.

Effect of tube drainage compared with conventional suturing on postoperative discomfort after extraction of impacted mandibular third molars

Dental anxiety for unerupted mandibular third molars extraction in children under local anesthesia is a tricky problem. The purpose of this study was to compare psychological and physiologic findings of extractions of unerupted mandibular third molars in children by piezosurgery and conventional osteotomy. This prospective, single-center, double-blind study included children who required extraction of mandibular third molars under local anesthesia. All subjects were randomly divided into two groups: piezosurgery and conventional osteotomy (control). The primary outcome variables were dental anxiety assessed by the Modified Child Fear Survey Schedule Dental Subscale (CFSS-DS) and postoperative pain qualified by the visual analog scale (VAS). Secondary outcome variables included blood pressure, heart rate, saturation, and operation duration. The data were analyzed by t-test and chi-square test (P ≤ 0.05). All 40 study patients (37.5% males and 62.5% females with an average age of 14.43 ± 1.32years) completed the entire trial. There were no statistically significant differences observed between the two groups in terms of gender allocation, age, side of extraction, and Winter's Classification (P > 0.05). The operation duration of the piezosurgery group was significantly longer than the conventional osteotomy group (P < 0.01). The VAS scores showed that pain levels of children in the piezosurgery group were significantly less than the conventional osteotomy group on the first and third days postoperatively (P < 0.05 and P < 0.01, respectively). The CFSS-DS score in the piezosurgery group significantly decreased compared to the conventional osteotomy group (P < 0.05). Compared with the conventional osteotomy group, a significant decrease in heart rate, and lower systolic and diastolic blood pressures were observed after extraction in the piezosurgery group (P < 0.05 and P < 0.01, respectively). Compared with conventional osteotomy, piezosurgery can effectively reduce postoperative pain and have some effect in relieving dental anxiety for the extraction of unerupted mandibular third molars in children. Piezosurgery may be a viable technique for the extraction of unerupted mandibular third molars in children under local anesthesia.