Inferior Alveolar Nerve Injury Research Articles

Histological assessment of potential inferior alveolar nerve injury following osteotomy of the mandibular buccal cortex using a piezoelectric saw.

The present study aimed to evaluate the effect of Piezosurgery on histopathologic features of the inferior alveolar nerve (IAN) damage after osteotomy of the buccal cortex of the mandible using piezoelectric devices in Hamdani sheep.A total of ten healthy mature female sheep were included. Each side of the mandible underwent two different experiments: the first experiment operated directly on the mental nerve by touching and activating the piezo tip on the nerve for ten seconds for the left side and thirty seconds for the right side. In the second experiment, the inferior alveolar nerve was touched by an activated piezo tip inside the mandibular canal for ten seconds on the left side and thirty seconds on the right side. All the nerve samples underwent histopathological evaluation, and the scoring system was performed to assess the nerve structures. Mental nerves exposed to piezo tip for 10 seconds showed mild abnormality including disruption of the perineurium with the endoneurium remaining intact. Mental nerves exposed for 30 seconds showed moderate injury with destruction of the perineurium and moderate degeneration of nerve fibers, nevertheless, the endoneurium remained continuous with normal node of Ranvier. Severe damage of the inferior alveolar nerve was seen after exposure to piezo tip for 10 seconds, which showed sloughing of the perineurium and severe vacuolar degeneration of nerve fibers, partial disruption of the endoneurium; however, the axons were still intact. Inferior alveolar nerves exposed for 30 seconds revealed destruction of the perineurium, marked vacuolar degeneration of nerve fibers, focal damage of axon and loss of endoneurium (axonotmesis).Piezosurgery devices have the potential to cause severe nerve damage during surgery and should be used very carefully.

Radiographic Predictors of Postoperative Inferior Alveolar Nerve Injury in Mandibular Third Molar Surgery

BackgroundCone-beam computed tomography (CBCT) provides additional three-dimensional information on the relationship between the mandibular third molar (M3M) and the inferior alveolar nerve (IAN). As such, CBCT is being increasingly utilized in pre-operative M3M assessment. PurposeThe purpose of the study was to compare the radiographic findings on panoramic and CBCT and their association with post-operative IAN paresthesia. Study design, setting and sampleWe conducted a retrospective cohort study in a sample of patients referred to the Department of Oral and Maxillofacial Surgery at the Royal Dental Hospital of Melbourne, for management of impacted M3Ms. Patients were included in this study if they had one or more high risk findings on OPG, had both OPG and CBCT imaging taken and if at least one M3M had been extracted. Subjects were excluded from this study if their M3Ms were not extracted or if a CBCT was not indicated. Independent variablesThe independent variable was radiographic features identified on OPG (Rood and Shehab’s radiographic signs, root morphology, impaction type, Pell and Gregory classification) and CBCT (number and location of roots, severity of IAN compression and the presence of ankylosis). Outcome variableThe outcome variable was post-operative neurosensory function defined as any reported paresthesia at 2-week post-procedural review. CovariatesThe covariates were patient demographic information (age, sex). AnalysesVariables were initially assessed with univariate logistic regression analysis to determine factors related to developing post-operative paresthesia. Multivariate logistic regression analysis was then used to assess the association between positive univariate study variables and post-operative paresthesia, while adjusting for potential confounders. Covariates were assessed using an omnibus likelihood ratio test and included if they were statistically significant at the p<0.05 level. ResultsThe study sample consisted of 257 subjects who underwent surgical removal of n=386 M3Ms. The mean age was 25.9 (SD = 7.05). The panoramic features of narrowing of canal, diversion of canal and dark/bifid roots were identified as statistically significant associations of post-operative paresthesia. No CBCT features were significantly associated of post-operative paresthesia. Conclusions and RelevanceCertain panoramic features, along with patient age, are significant predictors of IAN paresthesia. CBCT findings were not significant predictors upon multivariate analysis, thus additional CBCT imaging did not significantly improve ability to predict paresthesia.

Management and treatment modalities of inferior alveolar nerve injuries: Review of literature

Management and treatment modalities of inferior alveolar nerve injuries: Review of literature

The Comparison of 940nm and 810nm Diode Laser Effects on the Repair of Inferior Alveolar Sensory Nerve Injury: A Clinical Trial.

Healing of the inferior alveolar nerve injury during dental procedures is one of the biggest concerns of dentists. There are still debates on different treatment modalities. This study aimed to compare the effect of 940nm and 810nm diode lasers on the repair of the inferior alveolar sensory nerve. In this single-blinded randomized clinical trial, 39 patients with inferior alveolar nerve injury were divided into three groups: 1. 810nm laser irradiated, 2. 940nm laser irradiated, and 3. No laser irradiation (control group). All patients were treated in 12 sessions (3 days per week) and evaluated using a complete clinical neurosensory test (CNT), including brushstroke, 2-point discrimination, pinprick nociception, and thermal discrimination before and after treatment. The mean dysesthesia of the patient treated with 810nm diode laser was significantly lower than the control group in all sessions (the 1st (p= 0.003), 3rd (p= 0.008), 7th (p= 0.006), and 12th sessions (p= 0.005)). The 810nm laser resulted in more satisfaction in patients than the control group in almost all sessions (1st (p< 0.001), 7th (p= 0.028), and 12th (p= 0.006)). More patient satisfaction was seen in the 1st and 3rd sessions in the 810nm laser than in the 980nm laser (p< 0.001 and p= 0.003, respectively). 810nm diode laser can be better than 940nm in repairing inferior alveolar sensory nerve damage.

Do we consent to change? An evaluation of oral and maxillofacial outpatient department dentoalveolar consent forms

Obtaining informed consent before performing any dentoalveolar procedure is a professional, ethical, and legal obligation. Prior to this work, in this oral and maxillofacial department, no standardised consent process existed for dentoalveolar procedures. A targeted literature review established localised gold standards for dentoalveolar procedures, and retrospective data from 56 dentoalveolar consent forms over a four-week period assessed baseline compliance with these standards. Data analysis identified that risks of dry socket and trismus were documented in only 7% of cases, and maxillary tuberosity fracture was never documented. Thirty-three per cent of lower third molar cases did not include consent for inferior alveolar nerve injury. Findings were discussed in a departmental audit meeting, and a root cause analysis identified memory failure, repetition fatigue, and varying clinician knowledge and experience, as key drivers. The evidence base and localised gold standards were discussed. A standardised, bilingual, triple-copy dentoalveolar consent form was developed, including predefined indications, additional procedures, and risks, in a tick-box format. This form was presented to the Department of Patient Safety and Quality and gained local approval. Cases completed with the new form will now be evaluated against the localised gold standards, with a mixed-methods feedback survey investigating staff and patient opinions. Local processes for obtaining and documenting valid consent for dentoalveolar treatment were found to be inconsistent and frequently inadequate. Fifteen localised gold standards were set, and a new standardised consent form developed, which will be evaluated for effectiveness and acceptability.

Protocol for Diagnostic Test Accuracy Study: Evaluation of Cone Beam Computed Tomography (CBCT) in Prediction of Inferior Alveolar Nerve Injury as Compared to Orthopantomography (OPG) Secondary to Surgical Removal of Impacted Mandibular Third Molars.

Introduction Impairment of the inferior alveolar/dental nerve (IAN) is a relatively uncommon complication after lower wisdom tooth removal. Studies report varying incidences of IAN injury, with dysesthesia being noted as particularly distressing and 0-0.9% cases extending for a long duration. Neurosensory disruptions can severely impact speech, chewing, swallowing, and social interactions, leading to chronic pain and a lower quality of life. It also poses a risk of inadvertent injuries during meals. Although orthopantomogram (OPG) is primarily used for diagnosis, but when the lower wisdom tooth and nerve are in close approximation, cone beam computed tomography (CBCT) is recommended, despite its higher cost and radiation exposure. A white paper on third molar management necessitates further research on CBCT's role, citing conflicting evidence. Further in a multicentric trial, the difference between the OPG versus CBCT group was not statistically significant due to the low incidence of IAN injuries. They have emphasized the need for more well-designed studies to reach a statistically significant conclusion by meta-analyses. Hence, this study aims to provide additional evidence. Methods It is a two-arm, parallel, diagnostic study design involving individuals between the ages of 18 and 50 years, requiring lower wisdom tooth removal that is closely approximated with the nerve. Eligible adults, based on the specified inclusion/exclusion criteria, will be recruited into the study; informed consent will be obtained; then assigned randomly to the OPG or CBCT group using a random computer-generated sequence. Extractions will be done under local anesthesia using a standard surgical protocol with odontectomy. Surgical variables will include the experience of the surgeon, amongst others. The outcome variables will be recorded using patient interviews (subjective) and objective examinations from day one up to six months after surgery. The primaryoutcome will comprise the number of patients reporting abnormal sensations post-surgery. Secondary outcomes will include objectively confirmed IAN injuries and permanent IAN injuries (>6 months). Results will be analyzed statistically to look for significance and possible risk factors associated with it. Results If a statistically significant result is obtained, then we can deliberately reduce CBCT referrals and reserve them only for high-risk cases, wherein the risk of IAN injury cannot be predicted by OPG alone. If the experience of the surgeon proves to be an important risk factor, then it can also help refer high-risk patients to surgeons with more experience. Conclusion If CBCT proves to be statistically superior to OPG in the prediction of nerve injury, then we will be able to avoid significant morbidity and improve the quality of life of such patients by either modifying the surgical steps or by choosing other conservative treatment modalities. Further, this may reduce unnecessary CBCT referrals, thus reducing radiation exposure, the cost to patients, and, in turn, national healthcare expenditure. Besides, CBCT is not available at all centers, so a lot of low-risk patients can be managed safely at primary health centers, thus reducing the urban patient load.

Examination of the duration of vitamin B12 administration for hypoesthesia caused by inferior alveolar nerve injury after horizontally impacted mandibular third molar: A retrospective study

ObjectiveThis study aimed to assess the time to cure of hypoesthesia caused by inferior alveolar nerve (IAN) injury after horizontally impacted mandibular third molar (M3) extraction under continuous administration of mecobalamin, a vitamin B12 preparation, and factors that influence the time to cure. MethodsThis was a single-center retrospective study including 33 patients who experienced hypoesthesia after horizontally impacted M3 extraction and were treated with continuous oral administration of mecobalamin alone. The patients were divided into cured (n = 28) and uncured groups (n = 5). Demographic and clinical data were collected and analyzed. ResultsOf the 33 patients, 5 (15 %) reported uncured hypoesthesia. The median time to cure of hypoesthesia with mecobalamin administration was 33 (range, 6–202) days, and no cure beyond 7 months was reported. Age (≥30 years), Pell and Gregory classification (Position), and presence of Rood and Shehab signs ("interruption of white line of canal" and "diversion of canal") were significantly associated with prolonged time to cure. ConclusionsIt may be necessary to evaluate the efficacy of mecobalamin for IAN injury after horizontally impacted M3 extraction approximately 30 days after the initiation of administration and consider treatment modification or additional treatment within approximately 7 months.

A comparative study of a two-stage surgical approach combining coronectomy with microimplant anchorage traction for extraction of impacted mandibular third molars with different traction angles

Objective: To establish a two-stage surgical procedure of impacted mandibular third molars (IMTMs) extractions assisted by coronectomy and microimplant anchorage traction and to investigate the influencing factors of root movement and the effects of different traction angles on the clinical outcomes. Methods: Fifty-three IMTM in contact with inferior alveolar nerve (IAN) that underwent tooth extraction in the Peking University School of Stomatology from January 2022 to June 2023 were included, with coronectomy and microimplant anchorage implantation in the first stage of the surgery, root traction was achieved with orthodontic elastic and microimplant anchorages by about 600 g of force, when the IMTM root was detached from IAN, a second surgery was performed to extract the residual root. The basic information of patients and M3M, data on the microimplant anchorage implantation and traction, imaging measurements, and complications were recorded and analyzed. Results: The movement distance of the residual roots was (1.80±0.92) mm, and the duration of traction was (32.9±7.9) d. Multiple linear regression analysis showed that the residual root movement distance was significantly correlated with age, gender, number of roots, traction angle, and depth of the distal bone defect of the second molar (P<0.05). The smaller the traction angle, the more significant the movement of the residual roots (P=0.044). In one case (1.9%, 1/53), the patient experienced abnormal sensation in the lower lip 16 days after traction. Conclusions: The two-stage surgical method of combined coronectomy with rapid traction technique to extract the IMTM allows for rapid movement of the residual root and reduces the risk of IAN injury. The efficiency of root movement can be accelerated by appropriately reducing the traction angle during surgery. The traction effect can be predicted based on indicators such as age, gender, number of roots and depth of distal bone defects of second molar.

The unilateral sagittal split osteotomy: A useful tool in the armamentarium for deeply impacted mandibular third molars

The unilateral sagittal split osteotomy may not be a particularly popularized method to access and remove impacted mandibular third molars (M3Ms). However, in unusual cases of deep impaction, it can provide a surgical option that minimizes bone removal and may reduce the risk of iatrogenic mandibular fracture and inferior alveolar nerve (IAN) injury, depending on the position of the third molar relative to the neurovascular bundle. CPD/Clinical Relevance: The unilateral sagittal split osteotomy may present an alternative method for removing impacted mandibular third molar teeth in certain situations.

Mandibular Nerve and Lingual Nerve Injuries and Their Management Based on Aetiology, Time of Repair and Method of Intervention: A Systematic Review

Introduction: The purpose of this study was to scientifically review to determine the incidence, prevention protocols and recovery rate and reach a desirable protocol for the management of inferior alveolar nerve (IAN) injury and lingual nerve (LN) injury using the comprehensive overview of literature during various maxillofacial surgical procedures. Materials and Methods: Literature was selected through a search of PubMed, Cochrane Library and Google Scholar electronic databases. Articles from January 2010 to March 2023 were searched. All language articles with a minimum of 6-month patient follow-up and injury analysis by a patient’s reporting, radiographic and neurosensory testing were selected. Results: In total, 52 literature sources were reviewed, and 21 of the most relevant articles that are suitable to the criteria were selected. The impact of lower third molar removal (especially impacted) on the LN injury and IAN injury was clearly seen. Conclusions: Based on the study, it was clear that most injuries were occurring during removal of mandibular third molar. Thus, cone-beam computed tomography-based pre-operative analysis is a must in such cases. The results were significantly better in the early treatment group compared to the late group. Direct nerve repair without tension gives the best surgical outcome than other methods. Autogenous nerve graft was superior amongst other grafts which were used. Further studies were required to open a new paradigm for nerve repairs.

Frequency of Inferior Alveolar Nerve Injury During Third Molar Extraction.

To determine the frequency of inferior alveolar nerve injury during third molar extraction and the associated factors. Descriptive study. Place and Duration of the Study: Department of Oral and Maxillofacial Surgery, Ayub Teaching Hospital, Abbottabad, Pakistan, from July to December 2021. A total of 163 patients with third molar surgery were included. Patients were followed up after one week, one month, and three months of duration. The frequency of inferior alveolar nerve injury was determined as well as its relationship with other surgical variables like age, gender, type of impaction, buccal flap retraction, bone cutting, tooth splitting, and duration of surgery via Chi-square test. The frequency of inferior alveolar nerve injury was found to be 1.2% (n = 02). None of the surgical variables had a statistically significant association with it (p >0.05). The frequency of nerve injury of the inferior alveolar nerve during extraction of the third molar was 1.2%. Proper treatment planning, using advanced radiography, experienced surgeon, and proper technique can help in lowering nerve injury risk. Inferior alveolar nerve injuries, Molar, Tooth extraction, Paraesthesia.

Inferior alveolar nerve injury resulting from different implant rotary instruments: An ex vivo comparative study in human cadaveric mandibles

The present study aimed to evaluate the degree of nerve injury on inferior alveolar nerve (IAN) by different implant drills resulting from direct canal intrusion into inferior alveolar canal (IAC). A cadaveric study involving 7 human mandibles was performed to evaluate mechanical injury of canal enclosed IAN resulting from different drills. In group 1, osteotomies were created using different drills with 1 mm of intracanal intrusion, simulating accidental drill intrusion into canal. In group 2, drilling was stopped when the tip has breached into IAC, limited by tactile feedback of operator. The depth and width of nerve defects were assessed using optical coherence tomography. A significant difference in defect depth was found (p < 0.001) in group 1. A sinus lift reamer inflicted the least damage (0.068 ± 0.022 mm). It was also found that the mean defect depth was significantly different when a twist drill was used (p = 0.016). Sinus lift reamer can be used safely for osteotomy preparation in mandible when bone height is limited or when radiographic visualization of canal is poor. Bone corticalization around IAC does not provide adequate protection for IAN in the event of accidental intracanal intrusion.

Risk Factors Associated With Inferior Alveolar Nerve Injury After Extraction of Impacted Lower Mandibular Third Molars: A Prospective Cohort Study

BackgroundInferior alveolar nerve (IAN) injury is one of the complications of impacted lower mandibular third molar (LM3) extraction. Given the unknown prognosis of IAN injuries and limited treatment options, it is critical to understand the risk factors of IAN injury before LM3 extraction. PurposeThe study purpose was to identify risk factors associated with IAN injury after LM3 extraction. Study design, setting, sampleThis was a prospective cohort study including patients who underwent LM3 extraction from May to December in 2021 at authors’ institution. Patients with systemic diseases, previous maxillofacial surgeries or sensory abnormalities were excluded. Predictor variable(s)The predictor variable is composed of several risk factors. The variables were grouped into four categories: demographic, radiographic, procedure-related, and surgeon experience. Main outcome variable(s)The outcome variable was postoperative neurosensory disturbance coded as present or absent and was measured as one-month (transient) and one-year (permanent). CovariatesNot applicable. AnalysesThe measurement data were represented by mean and standard deviation (SD). The association of each variable with the presence of IAN injury was tested by the chi-square test. Statistical significance was accepted at p < 0.05. ResultsThe study sample was consisted of 705 patients (37.0% male) with an average age of 28.51 ± 6.51 years. A total of 17/705 (2.4%) and 4/705 (0.57%) patients developed transient and permanent IAN injury. The results demonstrated that the following factors were associated with higher rates of transient injury: use of chisels during surgeries (6.4%; 95% CI: 2.7-12.3; p=0.02; RR=11.4), LM3s located below the IAN canal (8.7%; 95% CI: 4.3-15.7; p<0.01; RR=7.3), compressed contact between LM3s and the IAN canal (36.4%; 95% CI: 12.3-78.2; p<0.001; RR=25.4), and not using corticosteroids after surgeries (3.8%; 95% CI: 1.9-6.5; p=0.03; RR=3.1). The only factor associated with permanent injury was compressed contact between LM3s and the IAN canal (18.2%; 95% CI: 2.2-62.3; p<0.001; RR=48.2). Conclusions and RelevanceClose proximity between LM3s and IAN canal, and the use of chisels, increase the risk of transient IAN injury. Corticosteroid treatment may promote nerve recovery. Compressed contact between LM3s and IAN canal is the only risk factor for permanent injury.

Endoscopically-assisted extraction of broken roots or fragments within the mandibular canal: a retrospective case series study

PurposeTo assess the impact of endoscope-assisted fractured roots or fragments extraction within the mandibular canal, along with quantitative sensory testing (QST) alterations in the inferior alveolar nerve (IAN).MethodsSix patients with lower lip numbness following mandibular third molar extraction were selected. All patients had broken roots or fragments within the mandibular canal that were extracted under real-time endoscopic assistance. Follow-up assessments were conducted on postoperative days 1, 7, and 35, including a standardized QST of the lower lip skin.ResultsThe average surgical duration was 32.5 min, with the IAN exposed in all cases. Two of the patient exhibited complete recovery of lower lip numbness, three experienced symptom improvement, and one patient remained unaffected 35 days after the surgery. Preoperative QST results showed that the mechanical detection and pain thresholds on the affected side were significantly higher than those on the healthy side, but improved significantly by postoperative day 7 in five patients, and returned to baseline in two patients on day 35. There were no significant differences in the remaining QST parameters.ConclusionsAll endoscopic surgical procedures were successfully completed without any additional postoperative complications. There were no cases of deterioration of IAN injury, and lower lip numbness recovered in the majority of cases. Endoscopy allowed direct visualization and examination of the affected nerve, facilitating a comprehensive analysis of the IAN.

Two-stage extraction by partial grinding of impacted mandibular third molar in close proximity to the inferior alveolar nerve.

Extraction of impacted third molars often leads to severe complications caused by damage to the inferior alveolar nerve (IAN). To proposes a method for the partial grinding of an impacted mandibular third molar (IMM3) near the IAN to prevent IAN injury during IMM3 extraction. Between January 1996 and March 2022, 25 patients with IMM3 roots near the IAN were enrolled. The first stage of the operation consisted of grinding a major part of the IMM3 crown with a high-speed turbine dental drill to achieve sufficient space between the mandibular second molar and IMM3. After 6 months, when the root tips were observed to be away from the IAN on X-ray examination, the remaining part of the IMM3 was completely removed. All IMM3s were extracted easily without symptoms of IAN injury after extraction. Partial IMM3 grinding may be a good alternative treatment option to avoid IAN injury in high-risk cases.

TREATMENT OF YATROGENIC POST-TRAUMATIC NEUROPATHY ASSOCIATED WITH ENDODONTIC THERAPY USING 3D TECHNOLOGIES

Post-traumatic neuropathy is one of the complications of endodontic treatment, represents a serious problem, manifested by sensory disturbances and has a significant negative impact on the quality of life of patients. Mechanical pressure on the filler causes swelling and hematoma and, due to the chemical action of the substance, neurotoxicity. The decision to treat a patient with trigeminal neuropathy requires complex treatment. Early surgical removal of excess endodontic material resulting from endodontic treatment provides the best prognosis for recovery. With the development of modern digital technologies, advances have been made in the endodontic treatment process. The presented clinical case describes original method for the treatment of endodontic inferior alveolar nerve injuries associated with endodontic therapy using surgical template obtained by three-dimensional software modeling. Using computed tomography software, a template was developed for drilling the bone in the projection of the localization of the material. The surgical template is printed with a 3D printer, after installation in the oral cavity, osteotomies are made under X-ray and excess material is removed, after which the patient is prescribed complex treatment. Results: After 2 weeks, the patient&amp;#39;s complaints disappeared. Sensory impairments were restored and had a positive impact on the patient’s quality of life. A control X-ray examination revealed regeneration of young bone tissue at the osteotomy site. Conclusion: The introduction of digital planning software and the use of 3D printed surgical guides in endodontic microsurgery have significantly improved treatment planning as well as operative and psychological comfort for patients.

Repair of Inferior Alveolar Nerve in Orthognathic Surgery Simulator (RIANOS): A Novel, Open-Source, Combined 3D Printed, and Ex-Vivo Chicken Sciatic Nerve Training Model

Study Design Face and content validation of a surgical simulation model. Objective Accidental transection of the inferior alveolar nerve (IAN) during bilateral sagittal split osteotomies (BSSO) has a reported incidence of up to 7%, determining important sensory disturbances in patients. Proper repair demands the need of microsurgical anastomosis skills. No previous training models have been described to simulate this. Therefore, we present a validated simulation model for intraoral repair of transected IAN. Methods A CT scan of an orthognathic surgery patient was modified and a 3D model of a mandible with BSSO was printed. Chicken thigh anatomy was reviewed, and 2.5 mm sciatic nerves were dissected and mounted in the model. In order to simulate intraoral work depth, it was put inside a dental phantom or medical glove box. The model was tested by a group of experts (n = 12), simulating a transected IAN repair inside the mouth with both loupes and a double visor surgical training microscope. A survey was conducted to assess Face and Content validity. Results The model was named RIANOS after Repair of Inferior Alveolar Nerve in Orthognathic Surgery Simulator. The printing cost of each model was approximately US$3 and the design file is open-source and available for download. All experts “Strongly Agreed” that the model was useful for training inferior alveolar nerve microsurgical repair and would consider implementing it with their residents. Conclusions We developed a low cost, reproducible, open-source simulator for IAN injury repair training during BSSO. Face and Content validity was achieved through evaluation by a group of experts.

Immediate implant placement in the posterior mandibular region was assisted by dynamic real-time navigation: a retrospective study

BackgroundEfficient utilization of residual bone volume and the prevention of inferior alveolar nerve injury are critical considerations in immediate implant placement (IIP) within the posterior mandibular region. Addressing these challenges, this study focuses on the clinical efficacy and implant accuracy of dynamic real-time navigation, an emerging technology designed to enhance precision in implantation procedures.MethodsThis study included 84 patients with 130 implants undergoing immediate placement in the posterior mandibular region. Stratified into dynamic navigation, static guide plate, and freehand implant groups, clinical indicators, including initial stability, distance to the inferior alveolar nerve canal, depth of implant placement, and various deviations, were systematically recorded. Statistical analysis, employing 1- or 2-way ANOVA and Student’s t-test, allowed for a comprehensive evaluation of the efficacy of each technique.ResultsAll 130 implants were successfully placed with an average torque of 22.53 ± 5.93 N.cm. In the navigation group, the distance to the inferior alveolar nerve and the depth of implant placement were significantly greater compared to the guide plate and freehand groups (P < 0.05). Implant deviation was significantly smaller in both the navigation and guide plate groups compared to the freehand group(P < 0.05). Additionally, the navigation group exhibited significantly reduced root and angle deviations compared to the guide plate group(P < 0.05), highlighting the superior precision of navigation-assisted immediate implant placement.ConclusionsIt is more advantageous to use dynamic navigation rather than a static guide plate and free-hand implant insertion for immediate posterior mandibular implant implantation.

System for automatically assessing the likelihood of inferior alveolar nerve injury

Inferior alveolar nerve (IAN) injury is a severe complication associated with mandibular third molar (MM3) extraction. Consequently, the likelihood of IAN injury must be assessed before performing such an extraction. However, existing deep learning methods for classifying the likelihood of IAN injury that rely on mask images often suffer from limited accuracy and lack of interpretability. In this paper, we propose an automated system based on panoramic radiographs, featuring a novel segmentation model SS-TransUnet and classification algorithm CD-IAN injury class. Our objective was to enhance the precision of segmentation of MM3 and mandibular canal (MC) and classification accuracy of the likelihood of IAN injury, ultimately reducing the occurrence of IAN injuries and providing a certain degree of interpretable foundation for diagnosis. The proposed segmentation model demonstrated a 0.9 % and 2.6 % enhancement in dice coefficient for MM3 and MC, accompanied by a reduction in 95 % Hausdorff distance, reaching 1.619 and 1.886, respectively. Additionally, our classification algorithm achieved an accuracy of 0.846, surpassing deep learning-based models by 3.8 %, confirming the effectiveness of our system.

Factors influencing inferior alveolar nerve injury after extraction of mandibular third molar.

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.