Inferior Alveolar Nerve Injury Research Articles

Blockade of Piezo2 Pathway Attenuates Inflammatory and Neuropathic Pain in the Orofacial Area.

Although previous studies suggest that Piezo2 regulates chronic pain in the orofacial area, few studies have reported the direct evidence of Piezo2's involvement in inflammatory and neuropathic pain in the orofacial region. In this study, we used male Sprague Dawley rats to investigate the role of the Piezo2 pathway in the development of inflammatory and neuropathic pain. The present study used interleukin (IL)-1β-induced pronociception as an inflammatory pain model. Subcutaneous injection of IL-1β produced significant mechanical allodynia and thermal hyperalgesia. Subcutaneous injection of a Piezo2 inhibitor significantly blocked mechanical allodynia and thermal hyperalgesia induced by subcutaneously injected IL-1β. Furthermore, the present study also used a neuropathic pain model caused by the misplacement of a dental implant, leading to notable mechanical allodynia as a consequence of inferior alveolar nerve injury. Western blot analysis revealed increased levels of Piezo2 in the trigeminal ganglion and the trigeminal subnucleus caudalis after inferior alveolar nerve injury. Furthermore, subcutaneous and intracisternal injections of a Piezo2 inhibitor blocked neuropathic mechanical allodynia. These results suggest that the Piezo2 pathway plays a critical role in the development of inflammatory and neuropathic pain in the orofacial area. Therefore, blocking the Piezo2 pathway could be the foundation for developing new therapeutic strategies to treat orofacial pain conditions.

Risk determination of inferior alveolar nerve injury after mandibular third molar extraction

Introduction. Extraction of impacted molars may be accompanied by complications, including inferior alveolar nerve (IAN) injury, with an incidence of up to 8.4% [3]. Among the risk factors for IAN trauma is the relationship between the molar and the mandibular canal (MC). The aim of the study is to evaluate the difficulty of extraction of impacted M3M and the risk of NAI injury based on radiological clichés. Materials and methods. A retrospective descriptive study was performed, including 25 molars. OPGs, and CBCTs of the patients were evaluated. Age, sex of patients; degree of inclusion according to Pell & Gregory; angulation of molars; Rood & Shehab signs were studied. Results. According to the degree of difficulty of the intervention, we obtained: low difficulty — 2 cases; medium — 21 cases; high — 2 cases. 84% of cases showed an association between more than one signs proposed by Rood & Shehab. The most common were loss of white line (33%), followed by MC narrowing and root darkening (22% each). The incidence of NAI injury was 8.3%. Conclusions. Risk prediction is useful in planning and facilitates decision making regarding the extraction technique of the impacted M3M.

Coronectomy of impacted mandibular third molars: a clinical and radiological retrospective case series study with 2-9 years of follow-up.

Impacted mandibular third molars occasionally are in intimate relation to the inferior alveolar nerve (IAN). Coronectomy has been proposed as a good alternative to prevent injury of the IAN. The present study evaluates the clinical and radiological outcomes of impacted mandibular third molars presenting radiographic signs associated with a high risk of IAN injury, and which were treated with the coronectomy technique. A retrospective case series evaluated the outcomes of coronectomies of impacted mandibular third molars. The inclusion criteria were: available preoperative, immediate postoperative and two-year panoramic radiographs, preoperative cone-beam computed tomography (CBCT), and a complete case history. The clinical evaluation comprised intraoperative complications (mobilized fragments of root and damage to adjacent structures), short-term complications (sensory alterations and postoperative infection), and long-term complications (infection or oral exposure). The IAN position with respect to the roots, root shape, eruption status, third molar position, radicular-complex migration and bone above roots were radiographically evaluated as well. Approximately a total of 2000 mandibular third molars were removed from 2011 to 2022. Of these, 39 molars in 34 patients were partially extracted using the coronectomy technique. The mean age was 36 years (range 22-77), and the mean follow-up was 28 months (range 24-84). There were two short-term postoperative infections. One of them was resolved through reintervention to remove the roots after antibiotic treatment, while the other required hospital admission and removal of the roots. One case of short-term transient lingual paresthesia was also recorded. Two long-term oral exposures were detected, and the root fragments had to be extracted. There were no permanent sensory alterations. In our case series of 39 impacted mandibular molars in intimate contact with the IAN and treated with the coronectomy technique, the number of complications was low (two infections and a single case of transient lingual paresthesia), and no permanent sensory alterations were observed. Prospective studies, especially randomized clinical trials, are needed to compare this technique with conventional extraction.

Coronectomy: A Knowledge, Attitude and Practice Survey (KAP) Among Oral and Maxillofacial Surgeons.

Since mandibular third molars are frequently impacted, third molar extractions are among the most common procedures performed by oral surgeons (35.9-58.7% of all surgical procedures). Inferior alveolar nerve (IAN) injury is major postoperative complication in 0.81-22% of the cases leading to a permanent injury in 1-4% of the cases. Prior studies have proven that coronectomy, a procedure that involves the removal of the crown and coronal one-third of the roots of the third molar with intentional retention of the two-third apical roots to protect the IAN, can thus prove to be a viable alternative in such cases of close proximity to the IAN. This study was conducted in India to determine the knowledge, attitudes, and practices of oral and maxillofacial surgeons regarding coronectomy and its role in the prevention of IAN injury. The questionnaire entitled: "Coronectomy: A Knowledge, Attitude and Practice (KAP) Survey among Oral and Maxillofacial Surgeons" was sent to 120 oral and maxillofacial surgeons. Five questions in each domain, i.e., knowledge, attitude, and practice were designed to know the level of awareness, acceptance, and current status of the performance of coronectomy among oral and maxillofacial surgeons (OMFS). Teeth with acute infection and mobile teeth were excluded from the consideration of coronectomy procedures. Out of the 120 questionnaires sent, 50 responses were obtained, thus producing a response rate of 41.6%. The male-to-female ratio in the study was 34:16. 52% of the surgeons had performed up to 5 coronectomies during their entire practice, while 16 % had never even attempted the procedure. Only 42% of the respondents preferred coronectomy, but most of the surgeons were in support of practice-oriented continuing.

High- Risk Factors Associated with Inferior Alveolar Nerve Injury Following Removal of the Third Molars: A Preliminary Study

PURPOSE: This study aims to determine the incidence of inferior alveolar nerve (IAN) injury following the extraction of the lower third molars (LTMs) and to identify the demographic, radiographic, and intra-operative risk factors associated with this complication. MATERIALS & METHODS: Fifty LTMs from 47 patients were included in this prospective clinical study. Demographic data and intra-operative parameters including operation time, bone removal and duration, excessive bleeding and IAN exposure were recorded. Bone retention, anatomical position of LTMs (Pell&Gregory and Winter classification) and 5 radiographic criteria proposed by Rood and Shehab were evaluated on panoramic images, whereas the distance between roots and the inferior alveolar canal (IAC), the cortication status of IAC, and the buccolingual position of IAC were examined on CBCT images. Chi-square test was used to compare the presence of IAN injury with variables. A p-value < 0.05 was considered as statistically significant. RESULTS: The incidence of temporary IAN injury was 6% among study population. No permanent IAN injury was observed. Excessive bleeding (p=0.007), IAN exposure (p=0.007), the lingual position of IAC (p=0.035) and dumbbell-shaped IAC (p=0.002) were found to be associated with increased risk of temporary IAN injury. CONCLUSION: Identification of high-risk factors is essential for predicting the risk of IAN injury, and determining the most convenient treatment plan for each case. Further studies with larger study samples are needed both to confirm the risk factors that are proposed in the present study and to identify the other potential ones.

The effect of root orientation on inferior alveolar nerve injury after extraction of impacted mandibular third molars based on propensity score-matched analysis: a retrospective cohort study

BackgroundThe injury of the inferior alveolar nerve (IAN) is one of the most serious complications of impacted mandibular third molars (IMTMs) extraction. The influence of the root orientation of IMTMs on IAN injury is still controversial. A deeper understanding of the risk factors of IAN injury conduces to better prevention of IAN injury. This study aims to explore whether root orientation is an independent risk factor of IAN injury during IMTMs extraction using the statistical strategy of propensity score matching (PSM).MethodsThis retrospective cohort study included 379 patients with 539 cases of high-risk IMTMs screened by panoramic radiography and cone beam computed tomography. The IAN injury incidence after extraction of different groups of IMTMs was analyzed using the chi-square test or Fisher’s exact test. The correlation between third molar root orientation and impaction depth/contact degree with IAN was evaluated by the Lambda coefficient. Based on PSM for balancing confounding factors including age, sex, impaction depth, and contact degree, the effect of root orientation on the incidence of IAN injury was further analyzed using Fisher’s exact test.ResultsThere were significant group differences in IAN injury incidence in impaction depth, root orientation, and contact degree of root-IAC before PSM. Root orientation was correlated with impaction depth and contact degree of root-IAC. After PSM, there were 9 cases with IAN injury and 257 cases without IAN injury. There were significant group differences between the buccal and non-buccal groups after PSM, and the risk of IAN injury was higher when the root was located on the buccal side of IAC (OR = 8.448, RR = 8).ConclusionsRoot orientation is an independent risk factor of IAN injury, and the risk is higher when the root is located on the buccal side of IAC. These findings could help better evaluate the risk of inferior alveolar nerve injury before the extraction of IMTMs.

Relationship of the Degree of Nerve Exposure and Surgical Manipulation and Short-Term Neurosensory Disturbance Following Sagittal Split Ramus Osteotomy: A Prospective Study

BackgroundNeurosensory disturbance (NSD) is a common complication after sagittal split ramus osteotomy (SSRO) due to inferior alveolar nerve (IAN) injury. The impact of intraoperative nerve manipulation on NSD remains debated. PurposeThe purpose of this study was to evaluate the influence of IAN exposure and manipulation during SSRO on functional sensory recovery (FSR). Study designThis was a single-center, prospective cohort study of 40 patients undergoing SSRO at Mahidol University, from December 2020 to December 2021. The inclusion criteria were patients aged 20-34, ASA Class I-II. The exclusion criteria were patients with systemic bone disease, history of head and neck or neurological pathology, previous SSRO or incomplete data collection. Predictor variableDegree of intraoperative nerve manipulation was divided by the attending surgeon as follows; 1) Nerve fully encased in distal segment and not visible (NS); 2) Nerve encased in distal segment but partially visible (DS) ; 3) Nerve partially encased in proximal segment and fully dissected free (PS). Outcome variablesThe area of interest was divided into the lip and chin. The primary outcome was time to FSR. The secondary outcome was subjective patient report, using a visual analogue scale, compared to FSR. CovariatesThe covariates were sex, age, skeletal diagnosis, degree of movement, and concomitant genioplasty/subapical procedure. AnalysesKaplan-Meier survival analysis, Cox proportional hazards regression, and Mcnemar test were utilized. P-value < 0.05 was significant. ResultsIn the lip, the median times to FSR were; NS, 2 days; DS, 45 days; PS, 102 days. (Interquartile range: 77,127, 114, respectively) In the chin, the median times to FSR were; NS, 23 days; DS, 92 days; PS, 87 days. (Interquartile range: 77, 161, 101, respectively.) Nerve manipulation significantly affected FSR in the lip and chin (p= 0.001, <0.001, respectively. Cox hazard ratios for DS and PS were lower compared to NS. Patients consistently reported more NSD compared to FSR as per Mcnemar test. Conclusion and RelevanceAfter SSRO, FSR in the lip is prolonged when the IAN is partially encased in the proximal segment and released. This raises the question of the efficacy of surgically releasing a partially encased IAN.

Evaluation of Implant Placement Risk Levels in Partially Edentulous Patients Using Cone Beam Computed Tomography.

This study aimed to evaluate the implant placement risk levels in partially edentulous patients using cone beam computed tomography (CBCT) and implant planning software. A total of 101 CBCT scans of partially edentulous patients were included. Evaluations of jawbone anatomy, vital structures' proximity, and the risk of inferior alveolar nerve injury with esthetic considerations were done on CBCT images using implant surgery software (BlueSkyPlan4;BlueSkyBio, Grayslake, IL). A total of 101 patients with 106 edentulous sites were examined. The mean ridge height of the non-esthetic zone was 10 mm and 14.4 mm in the maxilla and mandible, respectively. The period of edentulousness significantly affected the risk of placing implants in the non-esthetic zone (P<.05). The relation between gender and mandibular canal identification was significant (P<.01). A higher risk of implant placement is associated with a more extended period of edentulousness. The preoperative assessment revealed that the mandibular canal could be identified more easily in females than males; thus, nerve injury could be avoided. However, age hadno associated effect. Age has no associated effect on the implant placement risk levels for partially edentulous patients during dental implant planning. A higher risk of implant placement is associated with a more extended period of edentulousness. Mandibular canal identification during virtual preoperative assessment was higher in females.

Risk assessment of inferior alveolar nerve injury after wisdom tooth removal using 3D AI-driven models: A within-patient study

ObjectiveTo compare a three-dimensional (3D) artificial intelligence (AI)- driven model with panoramic radiography (PANO) and cone-beam computed tomography (CBCT) in assessing the risk of inferior alveolar nerve (IAN) injury after mandibular wisdom tooth (M3M) removal through a within-patient controlled trial. MethodsFrom a database of 6,010 patients undergoing M3M surgery, 25 patients met the inclusion criteria of bilateral M3M removal with postoperative unilateral IAN injury. In this within-patient controlled trial, preoperative PANO and CBCT images were available, while 3D-AI models of the mandibular canal and teeth were generated from the CBCT images using the Virtual Patient Creator AI platform (Relu BV, Leuven, Belgium). Five examiners, who were blinded to surgical outcomes, assessed the imaging modalities and assigned scores indicating the risk level of IAN injury (high, medium, or low risk). Sensitivity, specificity, and area under receiver operating curve (AUC) for IAN risk assessment were calculated for each imaging modality. ResultsFor IAN injury risk assessment after M3M removal, sensitivity was 0.87 for 3D-AI, 0.89 for CBCT versus 0.73 for PANO. Furthermore, the AUC and specificity values were 0.63 and 0.39 for 3D-AI, 0.58 and 0.28 for CBCT, and 0.57 and 0.41 for PANO, respectively. There was no statistically significant difference (p>0.05) among the imaging modalities for any diagnostic parameters. ConclusionThis within-patient controlled trial study revealed that risk assessment for IAN injury after M3M removal was rather similar for 3D-AI, PANO, and CBCT, with a sensitivity for injury prediction reaching up to 0.87 for 3D-AI and 0.89 for CBCT. Clinical significanceThis within-patient trial is pioneering in exploring the application of 3D AI-driven models for assessing IAN injury risk after M3M removal. The present results indicate that AI-powered 3D models based on CBCT might facilitate IAN risk assessment of M3M removal.

The effectiveness of photobiomodulation therapy on inferior alveolar nerve injury: A systematic review and META-analysis.

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.

INCIDENCE OF COMPLICATIONS AFTER THIRD MANDIBULAR MOLAR CORONECTOMY

Coronectomy is a technique that involves the removal of the crown of the third molar, leaving the root in place. It is recommended when the risks of complete extraction outweigh the benefits, especially in cases where there is a high risk of inferior alveolar nerve (IAN) injury. The success of coronectomy depends on adherence to the operating protocol, which is controlled by the oral sur­geon. The aim of this systematic review is to assess the incidence and nature of complications associated with the coronectomy of mandibular third molars. The systematic literature search was conducted according to PRISMA guidelines in MEDLINE (PubMed), and EMBASE (Sci­enceDirect) databases. A total of 287 titles were identi­fied. 9 studies met the final inclusion criteria. The results showed that coronectomy had a low incidence of IAN sensory disturbance, with 1.6% to 4.3% of cases expe­riencing such complications, while other studies recor­ded no cases of sensitivity loss. Infection and dry socket occurred in a small percentage of cases. Coronectomy is a safe and useful technique for treating impacted mandi­bular third molars. Similar or lower incidence of com­plications compared to those from extraction were seen. Further prospective homogenous randomized controlled clinical trials are necessary to evaluate the effectiveness of coronectomy in third mandibular molars.

Frequency of Inferior Alveolar Nerve Damage After Open Reduction and Internal Fixation in Mandibular Fractures

One of the most frequent injuries to the maxillofacial region is mandibular fracture. Numerous places experience fractures. The inferior alveolar nerve is often injured as a result of mandibular fractures. Objective: To ascertain how frequently patients in the oral and maxillofacial department of the Ayub Teaching Hospital in Abbottabad experienced inferior alveolar nerve injury following open reduction and fixation of a mandibular fracture. Methods: This was a Descriptive case series carried out at Oral and Maxillofacial Department, Ayub Teaching Hospital, Abbottabad after approval from the IRB of the institution and CPSP vide number (CPSP/REU/DSG-2018-010-2532). Using the formula to evaluate proportion with absolute precision and the following premises, the sample size was determined to be 96 using the WHO software for sample size computation in health studies: The expected percentage of inferior alveolar nerve injury following fixation in mandibular fracture is 45%, the confidence level is 95%, and the absolute precision is 10%. Results: The mean age of participants was 35.81±5.63 years with range from 26 to 45 years. Most common age group was 36-40 years and 41-45 years (n=26, 27.08%) followed by 26-30 years (n=23, 23.96%). There were 70 (72.92%) males and 26 (27.08%) females in the study. Majority (n=88; 91.67%) of the patients were given general anesthesia while the remaining (n=8; 8.33%) received local anesthesia. Perioperative inferior alveolar nerve injury was observed in 56 (58.33%) patients while permanent inferior alveolar nerve injury was diagnosed in 39 (40.63%) patients. Conclusions: Damage to inferior alveolar nerve is a frequent problem of open reduction and fixation of mandibular fracture. However, utmost care should be exercised to reduce its occurrence in patients with mandibular fracture.

Incidence neurosensory deficit in mandibular fractures.

Sensory disturbances in the inferior alveolar nerve (IAN) prior to treatment can be attributed to various factors, including the site, type of fracture, and fracture displacement. Therefore, it is of interest to assess the incidence of inferior alveolar nerve injuries associated with mandibular fractures before and after surgical treatment. Group A consisted of patients with inferior alveolar nerve paresthesia before treatment, while Group B consisted of patients with inferior alveolar nerve paresthesia after treatment. A significant difference was observed between the two groups, with a p-value of 0.031 (p <0.05) with the overall incidence of IAN deficit was 57.33% before treatment and 61.33% after treatment. These findings highlight the importance of promptly identifying and managing IAN injuries to minimize long-term consequences.

Extraction of impacted mandibular third molars in close proximity to the inferior alveolar canal with coronectomy-miniscrew traction to avoid nerve injury.

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.

Does the “Root Removal First” strategy prevent postoperative complications in the surgical removal of impacted mandibular third molars in the Pell and Gregory class C and horizontal position? — a randomized clinical trial

ObjectiveTo evaluate the clinical outcomes of the “Root Removal First” strategy in the surgical removal of impacted mandibular third molar (IMTM) in the class C and horizontal position.Materials and methodsA total of 274 cases were finally included in the statistics. The positions of IMTM in the horizontal position were confirmed by cone-beam computed tomography (CBCT). Cases were randomly divided into two groups: the “Root Removal First” strategy was applied in the new method (NM) group, and the conventional “Crown Removal First” strategy was executed in the traditional method (TM) group. The clinical information and relevant data upon follow-up were recorded.ResultsThe duration of the surgical removal and the incidence rates of lower lip paresthesia in the NM group were significantly lower than those in the TM group. The degree of mobility of the adjacent mandibular second molar (M2) in the NM group was significantly lower than that in the TM group at 30 days and 3 months post-operation. The distal and buccal probing depth of the M2, as well as the exposed root length of M2 in the NM group, were significantly lower than those in the TM group 3 months post-operation.ConclusionsThe “Root Removal First” strategy can reduce the incidence rate of inferior alveolar nerve injury and periodontal complications of the M2 in the surgical removal of IMTM in class C and horizontal position with high efficiency.Trial registrationChiCTR2000040063.

FREQUENCY OF PARESTHESIA DUE TO INFERIOR ALVEOLAR NERVE DAMAGE AFTER EXTRACTION OF MANDIBULAR THIRD MOLAR AMONG PATIENTS SHOWING DARKENING OF ROOT IN ORTHOPANTOMOGRAM

Background: Paresthesia is an abnormal dermal sensation with no apparent physical cause. One of the everyday practices in any oral surgery setup is the extraction of the impacted mandibular third molars surgically. Precise measurement of the bone present for support of the implant coronal to the inferior alveolar nerve (IAN) canal is the pertinent way to prevent IAN injuries.&#x0D; Objective: To assess the frequency of paresthesia due to IAN damage after mandibular third molar’s surgical extraction in patients with darkening of root on orthopantomogram.&#x0D; Material &amp; Methods: It was a descriptive case series study which took place in the department of Oral and Maxillofacial Surgery at Sharif Medical and Dental College, Lahore in a time frame of 6 months i.e. from December 2020 till May 2021. After meeting the inclusion/exclusion criteria, 200 patients were made part of the study program. Informed consent and demographic information was recorded. Surgical procedure of all these patients was done. Assessment was done post-operatively first after one week when patient came for suture removal by inquiring about the subjective perception of abnormal feeling or sensation on lower lip and chin area. Patients were then reappointed for a follow-up visit after 1 month as well.&#x0D; Results: Patients’ mean age was 28.05±3.94 years. There were 104 (52%) males and 96 (48%) females in the study population. There were 38 (19%) patients of distoangular impaction, 39 (19.5%) had horizontal impaction, 55 (27.5%) had mesioangular impaction while 68 (34%) had vertical impaction. The IAN paresthesia after 1st month of surgery was found in 13 (6.5%) patients.&#x0D; Conclusion: According to this study, the frequency of paresthesia after 1st month of surgery was 6.5% due to IAN injury after mandibular third molar surgery in patients with darkening of root as observed on orthopantomogram.&#x0D; Keywords: Inferior Alveolar Nerve, Orthopantomogram, Paresthesia, Third Molar Surgery.

A ramus cortical bone harvesting technique without bone marrow invasion

Autogenous bone grafts from the mandibular ramus are a known source of inadequate bone volume scenarios of the residual alveolar ridge. However, the conventional block-type harvesting technique cannot prevent bone marrow invasion, which can cause postoperative complications such as pain, swelling, and inferior alveolar nerve injury. This study aims to suggest a complication-free harvesting technique and present the results of bone grafting and donor sites. One patient received two dental implants with a complication-free harvesting technique that involves creation of ditching holes with a 1 mm round bur. Sagittal, coronal, and axial osteotomies produced grid-type cortical squares using a micro-saw and a round bur to confirm the cortical thickness. The grid-type cortical bone was harvested from the occlusal aspect, and the harvesting was extended through an additional osteotomy on the exposed and remaining cortical bone to prevent bone marrow invasion. The patient did not suffer postoperative severe pain, swelling, or numbness. After 15 months, the harvested site exhibited new cortical bone lining, and the grafted area had healed to a cortico-cancellous complex with functional loading of the implants. Our technique, grid-type cortical bone harvesting without bone marrow invasion, allowed application of autogenous bone without bone marrow invasion to achieve acceptable bone healing of the dental implants and to regenerate the harvested cortical bone.

Effects of Peripheral Nerve Injury on the Induction of c-Fos and Phosphorylated ERK in the Brainstem Trigeminal Sensory Nuclear Complex.

Sequential changes in brainstem and spinal cord neurons after traumatic injury to peripheral nerves are related to neuropathic pain symptoms. This study was conducted to elucidate the influence of nerve insult on stimulus-induced c-Fos expression and ERK phosphorylation by brainstem neurons. The brainstem trigeminal sensory nuclear complex (BTSNC) was examined for neuronal profiles immunolabeled with c-Fos and phosphorylated ERK (p-ERK) antibodies elicited by stimulation of the tongue with capsaicin after lingual or inferior alveolar nerve (IAN) injury. Abundant neuronal profiles immunolabeled for c-Fos and p-ERK elicited by capsaicin were distributed in the spinal trigeminal nucleus caudalis (Vc) without nerve injury. The spinal trigeminal nucleus oralis (Vo) contained limited numbers of these neuronal profiles after stimulation of the tongue. A significant reduction of these neuronal profiles in the ipsilateral Vc was detected after lingual nerve injury. After IAN injury, an increased number of neuronal profiles immunolabeled for c-Fos elicited by capsaicin was noted, while that of p-ERK was left unchanged in the ipsilateral Vc. On the both sides of the Vo, an increased number of capsaicin-induced neuronal profiles immunolabeled for c-Fos and p-ERK was detected after lingual or IAN injury. Differential effects of lingual or IAN injury on stimulus-induced c-Fos expression and ERK phosphorylation by Vo and Vc neurons may be involved in the complex nature of symptoms of trigeminal neuralgia.

Is Surgical Repair With Nerve Allograft More Cost-Effective Than Non-Surgical Management for Persistent Trigeminal Neuropathy? Initial Assessment With Markov Model

Persistent trigeminal neuropathy (PTN) is associated with high rates of depression, loss of work, and decreased quality of life (QoL). Nerve allograft repair can achieve functional sensory recovery in a predictable manner; however, it bears significant upfront costs. In patients suffering from PTN, is surgical repair with allogeneic nerve graft, when compared to non-surgical therapy, a more cost-effective treatment option? A Markov model was constructed with TreeAge Pro Healthcare 2022 (TreeAge Software, Massachusetts) to estimate the direct and indirect costs for PTN. The model ran for 40years with 1-year-cycles on a 40-year-old model patient with persistent inferior alveolar or lingual nerve injury (S0 to S2+) at 3months without signs of improvement, and without dysesthesia or neuropathic pain (NPP). The 2 treatment arms were surgery with nerve allograft versus non-surgical management. There were 3 disease states, functional sensory recovery (S3 to S4), hypoesthesia/anesthesia (S0 to S2+), and NPP. Direct surgical costs were calculated using the 2022 Medicare Physician Fee Schedule and verified with standard institutional billing practices. Non-surgical treatment direct costs (follow-up, specialist referral, medications, imaging) and indirect costs (QoL, loss of employment) were determined from historical data and the literature. Direct surgical costs for allograft repair were $13,291. State-specific direct costs for hypoesthesia/anesthesia were $2,127.84 per year, and $3,168.24 for NPP per year. State-specific indirect costs included decreased labor force participation, absenteeism, and decreased QoL. Surgical treatment with nerve allograft was more effective and had a lower long-term cost. The incremental cost-effectiveness ratio was -10,751.94, indicating surgical treatment should be utilized based on efficiency and cost. With a willingness-to-pay threshold of $50,000, the net monetary benefits of surgical treatment are $1,158,339 compared to $830,654 for non-surgical treatment. With a standard threshold incremental cost-effectiveness ratio of 50,000, the sensitivity analysis shows that surgical treatment would remain the preferred choice based on efficiency even if surgical costs were doubled. Despite high initial costs of surgical treatment with nerve allograft for PTN, surgical intervention with nerve allograft is a more cost-effective treatment option when compared to non-surgical therapy.

Application of Cone Beam Computed Tomography in Risk Assessment of Lower Third Molar Surgery

Risks of lower third molar surgery like the inferior alveolar nerve injury may result in permanent consequences. Risk assessment is important prior to the surgery and forms part of the informed consent process. Traditionally, plain radiographs like orthopantomogram have been used routinely for this purpose. Cone beam computed tomography (CBCT) has offered more information from the 3D images in the lower third molar surgery assessment. The proximity of the tooth root to the inferior alveolar canal, which harbours the inferior alveolar nerve, can be clearly identified on CBCT. It also allows the assessment of potential root resorption of the adjacent second molar as well as the bone loss at its distal aspect as a consequence of the third molar. This review summarized the application of CBCT in the risk assessment of lower third molar surgery and discussed how it could aid in the decision-making of high-risk cases to improve safety and treatment outcomes.