Preinterventional Third-Molar Assessment Using Robust Machine Learning.

Machine learning (ML) models, especially deep neural networks, are increasingly being used for the analysis of medical images and as a supporting tool for clinical decision-making. In this study, we propose an artificial intelligence system to facilitate dental decision-making for the removal of mandibular third molars (M3M) based on 2-dimensional orthopantograms and the risk assessment of such a procedure. A total of 4,516 panoramic radiographic images collected at the Center of Dental Medicine at the University of Zurich, Switzerland, were used for training the ML model. After image preparation and preprocessing, a spatially dependent U-Net was employed to detect and retrieve the region of the M3M and inferior alveolar nerve (IAN). Image patches identified to contain a M3M were automatically processed by a deep neural network for the classification of M3M superimposition over the IAN (task 1) and M3M root development (task 2). A control evaluation set of 120 images, collected from a different data source than the training data and labeled by 5 dental practitioners, was leveraged to reliably evaluate model performance. By 10-fold cross-validation, we achieved accuracy values of 0.94 and 0.93 for the M3M-IAN superimposition task and the M3M root development task, respectively, and accuracies of 0.9 and 0.87 when evaluated on the control data set, using a ResNet-101 trained in a semisupervised fashion. Matthew's correlation coefficient values of 0.82 and 0.75 for task 1 and task 2, evaluated on the control data set, indicate robust generalization of our model. Depending on the different label combinations of task 1 and task 2, we propose a diagnostic table that suggests whether additional imaging via 3-dimensional cone beam tomography is advisable. Ultimately, computer-aided decision-making tools benefit clinical practice by enabling efficient and risk-reduced decision-making and by supporting less experienced practitioners before the surgical removal of the M3M.

Positional assessment of lower third molar and mandibular canal using explainable artificial intelligence.

OBJECTIVE: The aim of this study is to automatically assess the positional relationship between lower third molars (M3i) and the mandibular canal (MC) based on the panoramic radiograph(s) (PR(s)). MATERIAL AND METHODS: A total of 1444 M3s were manually annotated and labeled on 863 PRs as a reference. A deep-learning approach, based on MobileNet-V2 combination with a skeletonization algorithm and a signed distance method, was trained and validated on 733 PRs with 1227 M3s to classify the positional relationship between M3i and MC into three categories. Subsequently, the trained algorithm was applied to a test set consisting of 130 PRs (217 M3s). Accuracy, precision, sensitivity, specificity, negative predictive value, and F1-score were calculated. RESULTS: The proposed method achieved a weighted accuracy of 0.951, precision of 0.943, sensitivity of 0.941, specificity of 0.800, negative predictive value of 0.865 and an F1-score of 0.938. CONCLUSION: AI-enhanced assessment of PRs can objectively, accurately, and reproducibly determine the positional relationship between M3i and MC. CLINICAL SIGNIFICANCE: The use of such an explainable AI system can assist clinicians in the intuitive positional assessment of lower third molars and mandibular canals. Further research is required to automatically assess the risk of alveolar nerve injury on panoramic radiographs.

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

OBJECTIVE: To 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. METHODS: From 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. RESULTS: For 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. CONCLUSION: This 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 SIGNIFICANCE: This 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.

Assessment of the prevalence and length of the anterior and caudal loops of the mental nerve as anatomical variants of exiting the mandible at the mental foramen using cone-beam computed tomography: a systematic review and meta-analysis.

OBJECTIVES: This systematic review aimed to identify the studies that performed cone-beam computed tomography analysis of the prevalence and length of the anterior loop (AL) and caudal loop (CL) of the mental nerve. MATERIALS AND METHODS: An electronic database search was performed across PubMed, EMBASE, Web of Science, Scopus, the Cochrane library, and Google Scholar. Original studies reporting the frequency and length of the AL and CL were selected. Qualitative synthesis and meta-analysis were then conducted to assess the prevalence and length of the AL and CL and their associations with age, gender, sides, and dentition status. RESULTS: A total of 21 studies were included in this review. The pooled prevalence of the AL (95% confidence interval) of the mental nerve at the patient and side level was 51% (31-71%) and 53% (37-69%) while the mean anterior loop length was 2.08 (1.46-2.70) mm. The pooled prevalence of the CL and mean caudal loop length were 100% and 4.73 (3.44-6.01) mm. No significant associations were found between the prevalence and length of the AL and CL and age, gender, sides, and dentition status. CONCLUSIONS: Overall, the pooled prevalence and mean length of AL of the mental nerve varied among different populations while CL seems to be a constant anatomical landmark with a longer CL than AL. CLINICAL RELEVANCE: Surgeons performing inter-foraminal oral surgeries like dental implant placement and genioplasty should be aware of the possible distance of the AL and CL to avoid iatrogenic mental nerve injury.

Assessment of Inferior Alveolar Nerve Position at the Region of First and Second Mandibular Molars in Dentate and Edentulous Sites Using Cone Beam Computed Tomography: A Cross-Sectional Study.

Determining the position of the Inferior alveolar nerve (IAN) is an important factor prior to any surgical procedure in the mandible such as dental implant insertion and surgical tooth extraction. The aim of this study was to compare the position of IAN in partially edentulous patients in the lower first and second molars in both missing and dentate sides. A total of 200 CBCT scans were chosen randomly and examined. On cross-sectional views, the distance between lower border of IAN canal and upper border of inferior cortex of mandible (IC) were measured at the site of dentate and edentulous mandibular first and second molar. Paired-sample t-test was used to analyze and compare measurements on right and left sides. A total of 100 males and 100 females with mean age of 46.05 ± 12.33 years were included. The IC distance measured in four pairs were as follows: Pair one: 80 cases with right missing 6 (mean ± SD = 3.73 ± 1.29 mm) and left present 6 (mean ± SD = 3.42 ± 1.20 mm), Pair two: 20 cases with right present 6 (mean = 3.20 ± 1.48 mm) and left missing 6 (mean ± SD = 3.96 ± 1.62 mm), Pair three: 54 cases of right missing 7 (mean ± SD = 3.83 ± 1.74 mm) and left present 7 (mean ± SD = 3.62 ± 1.74 mm), and Pair four: 46 case of right present 7 (mean ± SD = 3.49 ± 1.56 mm) and left missing 7 (mean ± SD = 3.84 ± 1.42). The IAN was statistically more distant from inferior cortex of mandible in the edentulous parts compared with the non-edentulous part (P < 0.05). The IAN was positioned farther from the inferior cortex of mandible in edentulous sites compared with dentate parts. Cautious consideration is essential in any surgical procedure and dental implant operations to prevent IAN injury.

The Effect of Mandibular Angulation on Preoperative Assessment of Dental Implant Insertion at Premolar Region: CBCT Study.

Backgrounds: This study investigated the effect of mandibular angulation on the perioperative evaluation of the implant placement at the premolar region on panoramic reconstructed images using cone beam computed tomography (CBCT). Methods: A total of six dried anonymous human mandibles was included. Two implants were inserted in the left and right first premolar region. CBCT scans were obtained from each mandible at the standard position, +20° extension, and -20° flexion. The distance of the implant from the anterior loop of the inferior alveolar nerve and mental foramen was measured. Mean absolute error (MAE) of the distance of the implant from both anatomical landmarks was measured. The Wilcoxon matched-pair signed-rank test was used for the comparison of the measurements. All data were analyzed with the Stata program (version 15.1). Results: No statistically significant differences were found between the distance of the implant from the mental foramen and the anterior loop of the inferior alveolar nerve up to 20° extension and flexion at both sides of the mandible. (All p > 0.1) However, a variable range of MAE (SD) in the distance of the implant from different anatomical landmarks was found (0.9 ± 0.7 to 3.3 ± 2.1). Conclusions: We found no statistical difference in measurements of the distance of the implant from two anatomical landmarks at different head positions up to 20° extension and flexion. However, clinically, variable range in the distance of the implant from anatomical landmarks should be considered. Our findings could alert dentists of the possibility of error up to 20° extension and flexion on the perioperative evaluation of dental implant placement.

Novel strategy to predict high risk of inferior alveolar nerve injury during extraction of lower third molars based on assessment of computed tomographic images of multiple anatomical features.

Preoperative assessment is essential to prevent inferior alveolar nerve (IAN) injury during surgical extraction of the lower third molar (LM3). Here, we aimed to establish an assessment system to predict IAN injury during surgical extraction of the LM3. We conducted a retrospective cohort study on 115 patients diagnosed as 'high-risk' based on our previous risk assessment method involving three anatomical features of the inferior alveolar canal using computed tomographic (CT) images. We evaluated the occurrence of neurosensory impairment in these high-risk patients, and its association with novel anatomic features based on CT images. Neurosensory impairments were observed in 19 patients (16.5%). The inferior alveolar canal major diameter (p < 0.0001) and lingual bone thickness (p = 0.0039) were significantly associated with the occurrence of neurosensory impairment during LM3 extraction. Receiver operating characteristic curves were used to determine cut-off values of these quantitative factors to specifically predict IAN injury. Preoperative risk assessment with quantitative factors based on anatomical features observed on CT images may facilitate more appropriate surgical planning for patients at a high risk of IAN injury.

The Assessment of Prolonged Inferior Alveolar Nerve Blockade for Postoperative Analgesia in Mandibular Third Molar Surgery by a Perineural Addition of Dexamethasone to 0.5% Ropivacaine: A Randomized Comparison Study.

Background: Perineurally adding dexamethasone to local anesthetics could enable postoperative analgesia. Our aim was to investigate the efficacy of 4 mg dexamethasone and 0.5% ropivacaine on the prolonged duration of mandibular anesthesia for postoperative analgesia during third molar surgery. Materials and method: The patients of both sexes, and in the age range of 17 to 50 yrs of age, received the Gow-Gates anesthesia. Group I received 4 mL of plain 0.5% ropivacaine, with perineurally added 1 mL/4 mg of dexamethasone; group II received 4 mL of plain 0.5% ropivacaine with perineurally added 1 mL of 0.9% saline; group III received 4 mL of plain 0.5 bupivacaine with perineurally added 1 mL of 0.9% saline. The prime anesthesia outcome was the duration of conduction anesthesia (DCA); the secondary outcome was the duration of analgesia (DAN) and analgesia before analgesic intake. Results: In 45 randomly selected subjects (mean age 27.06 ± 8.20), DCA was statistically longest in group I (n = 15) (592.50 ± 161.75 min, p = 0.001), collated with groups II (n = 15) and III (n = 15) (307.40 ± 84.71 and 367.07 ± 170.52 min, respectively). DAN was significantly the longest in group I (mean: 654.9 ± 198.4 min, p = 0.001), compared with group II (345.4 ± 88.0 min) and group III (413.7 ± 152.3 min), with insignificant adverse reactions. One-third of the operated patients absented from the use of analgesics. Conclusion: A amount 0.5% ropivacaine with dexamethasone usefully served as an analgesic with a success rate of 93.4% of the given anesthesia.

The Assessment of Neurosensory Disturbance Following Bilateral Sagittal Split Osteotomy With Subjective and Three-Dimensional Evaluation.

PURPOSE: Inferior alveolar neurosensory disturbance (IAND) is the most common complication of bilateral sagittal split osteotomy (BSSO). The aim of the present study was to evaluate IAND with subjective tests postoperatively and assess the relationship between three-dimensional measurements of the mandibular canal (MC) and IAND. METHODS: Eighteen patients (Mean age: 24.05 ±â€Š5.85 years) treated with BSSO were retrieved from the archive. Subjective tests (light touch, tactile sensitivity, 2-point discrimination, brush-stroke directional discrimination, sharp/blunt discrimination, dental vitality, questionnaire) and three-dimensional measurements related to MC and fixation screws were done postoperatively (on average 20.43 ±â€Š8.76 months after surgery). Statistical significance was set at P  < 0.05. RESULTS: Subjective test results were found compatible with each other except brush-stroke directional discrimination test. According to the questionnaire, IAND was apparent in all patients immediately after surgery, and recovery after 1 to 2 years was statistically significant ( P  < 0.05). Preoperative ramus width, medial and lateral cancellous bone lengths, the decrease in MC length, and the presence of screw in MC were not related to IAND ( P  < 0.05). CONCLUSIONS: There is a high incidence of IAND following BSSO, and the subjective tests are efficient to evaluate the disturbance. Spontaneous recovery of the nerve occurs during the follow-up periods. Instead of preoperative measurements of bone thickness, MC length, and the position of fixation screws, the surgical procedure seems to be more important in IAND occurrence.

Three-dimensional assessment of the anterior and inferior loop of the inferior alveolar nerve using computed tomography images in patients with and without mandibular asymmetry.

BACKGROUND: The purpose of this study was to investigate the differences in configuration and dimensions of the anterior loop of the inferior alveolar nerve (ALIAN) in patients with and without mandibular asymmetry. METHOD: Preoperative computed tomography images of patients who had undergone orthognathic surgery from January 2016 to December 2018 at a single institution were analyzed. Subjects were classified into two groups as "Asymmetry group" and "Symmetry group". The distance from the most anterior and most inferior points of the ALIAN (IANant and IANinf) to the vertical and horizontal reference planes were measured (dAnt and dInf). The distance from IANant and IANinf to the mental foramen were also calculated (dAnt_MF and dInf_MF). The length of the mandibular body and symphysis area were measured. All measurements were analyzed using 3D analysis software. RESULTS: There were 57 total eligible subjects. In the Asymmetry group, dAnt and dAnt_MF on the non-deviated side were significantly longer than the deviated side (p < 0.001). dInf_MF on the non-deviated side was also significantly longer than the deviated side (p = 0.001). Mandibular body length was significantly longer on the non-deviated side (p < 0.001). There was no significant difference in length in the symphysis area (p = 0.623). In the Symmetry group, there was no difference between the left and right sides for all variables. CONCLUSION: In asymmetric patients, there is a difference tendency in the ALIAN between the deviated and non-deviated sides. In patients with mandibular asymmetry, this should be considered during surgery in the anterior mandible.

A systematic review of the complications of high-risk third molar removal and coronectomy: development of a decision tree model and preliminary health economic analysis to assist in treatment planning.

Coronectomy is an alternative surgical technique for the management of high-risk third molars. It involves the removal of the crown of a tooth and the deliberate retention of the roots, thereby avoiding injury to the inferior alveolar nerve (IAN). Previous studies have suggested that it reduces the risk of nerve injury when compared with surgical extraction. The purpose of this study was to systematically review the incidence of complications following coronectomy such as IAN injury, pain, dry socket, infection, root migration, and need for re-operation. A comparative cost analysis of coronectomy and surgical extraction was done based on the results of the review. This provides an insight into the economic implications of the two procedures. A search through the MEDLINE database via Ovid, PubMed, Scopus, EMBASE via Ovid, and Web of Science, was carried out to extract randomised and non-randomised controlled trials. Four studies fulfilled the inclusion criteria. A meta-analysis was conducted to measure the overall effect of each outcome. The pooled odds ratio (OR) for IAN injury was 0.16 (95% CI 0.01 to 0.39). Coronectomy reduced this risk by 84%. Dry socket may occur less frequently following coronectomy whereas infection did not show a higher incidence with either intervention. Root migration was found to occur in 13%-85% of cases and the average incidence of re-operation was 2.2%. The ratio of the average costs was 1.12 favouring coronectomy if cone-beam computed tomography (CBCT) was not done prior to the procedure. If a scan was taken routinely for coronectomy, the cost ratio marginally favoured extraction. Coronectomy reduced the risk of nerve injury in high-risk third molars. Definitive conclusions, however, cannot be made for outcomes such as the need for re-operation, which may alter the cost ratio of coronectomy:extraction, as higher quality studies with longer follow-up are needed.

High resolution MRI for quantitative assessment of inferior alveolar nerve impairment in course of mandible fractures: an imaging feasibility study.

The purpose of this study was to evaluate a magnetic resonance imaging (MRI) protocol for direct visualization of the inferior alveolar nerve in the setting of mandibular fractures. Fifteen patients suffering from unilateral mandible fractures involving the inferior alveolar nerve (15 affected IAN and 15 unaffected IAN from contralateral side) were examined on a 3 T scanner (Elition, Philips Healthcare, Best, the Netherlands) and compared with 15 healthy volunteers (30 IAN in total). The sequence protocol consisted of a 3D STIR, 3D DESS and 3D T1 FFE sequence. Apparent nerve-muscle contrast-to-noise ratio (aNMCNR), apparent signal-to-noise ratio (aSNR), nerve diameter and fracture dislocation were evaluated by two radiologists and correlated with nerve impairment. Furthermore, dislocation as depicted by MRI was compared to computed tomography (CT) images. Patients with clinically evident nerve impairment showed a significant increase of aNMCNR, aSNR and nerve diameter compared to healthy controls and to the contralateral side (p < 0.05). Furthermore, the T1 FFE sequence allowed dislocation depiction comparable to CT. This prospective study provides a rapid imaging protocol using the 3D STIR and 3D T1 FFE sequence that can directly assess both mandible fractures and IAN damage. In patients with hypoesthesia following mandibular fractures, increased aNMCNR, aSNR and nerve diameter on MRI imaging may help identify patients with a risk of prolonged or permanent hypoesthesia at an early time.

Assessment of conduction anesthesia effectiveness using the angulated needle approach for the inferior alveolar nerve block.

BACKGROUND: Ambulatory painless surgery is dependent on local anesthesia effectiveness. AIM: Evaluating the anesthetic efficacy of the angulated needle approach (ANA) for the inferior alveolar nerve block (IANB). MATERIAL AND METHOD: Group I received direct IANB; group II received indirect IANB; group III received the IANB with ANA. The quality of anesthesia score (QAS), numerical pain intensity score (NRS), onset time of full anesthesia (OT), and perianesthetic complications were measured. RESULTS: Ninety patients (mean age: 37.47 ± 18.90, p = 0.027) of both sexes were split into three equal groups. Group III had the lowest QAS value with the success rate of 93.3%, compared to the statistically significantly worse QAS values of group II, with the success rate of 80% (p = 0.016). Group II had the statistically significant highest NRS values relative to group I (p = 0.002) and group III (p = 0.000001). The shortest OT occurred in group I, when compared to group II (p = 0.000484) and group III (p = 0.000498). The transient syncope and positive aspiration occurred in single cases. CONCLUSION: The ANA for the IANB could successfully serve as a "first choice", or as an "addendum technique" in the cases of multiple failed attempts for direct and indirect IANB techniques.

Pain assessment during mandibular nerve block injection with the aid of dental vibe tool in pediatric dental patients: a randomized clinical trial.

OBJECTIVE: This study aimed to evaluate the effectiveness of DentalVibe in pain reduction during local anesthetic injection compared to traditional injection in pediatric patients. METHOD AND MATERIALS: This cross-over randomized controlled clinical trial included a sample of 60 children, aged 5 to 7 years, who were selected based on the need for local anesthesia for bilateral mandibular pulpotomy treatment. They were randomly allocated into two groups. Each group received two mandibular nerve block injections, with a 2-week interval as the washing out period. At first appointment, mandibular nerve block injection was performed either with vibration using DentalVibe at the injection site or benzocaine gel 20% applied before local anesthetic injection; the alternative technique was used at the second appointment. In each visit subjective pain was evaluated using the Wong-Baker FACES Pain Rating Scale and objective pain was evaluated using the FLACC (Face, Legs, Activity, Cry, Consolability) scale. RESULTS: Assessment using the Wong-Baker FACES Pain Rating Scale showed that the mean pain levels in DentalVibe and traditional injection groups were 0.80 ± 1.34 and 2.60 ± 3.22, respectively. The mean pain levels according to the FLACC scale were 2.20 ± 2.04 and 3.13 ± 2.30 in the DentalVibe and traditional injection groups, respectively. Both scales showed statistically significant differences between the two groups in favor of DentalVibe (P < .001). A positive significant correlation between the two scales in the two interventions was recorded, where the Spearman rho was 0.41 for the DentalVibe group, and 0.52 for traditional injection group (P < .001). CONCLUSION: Compared to the traditional approach, DentalVibe reduced pain sensation during mandibular nerve block injection in pediatric patients.

Assessment of Mandibular Movement Monitoring With Machine Learning Analysis for the Diagnosis of Obstructive Sleep Apnea.

Importance: Given the high prevalence of obstructive sleep apnea (OSA), there is a need for simpler and automated diagnostic approaches. Objective: To evaluate whether mandibular movement (MM) monitoring during sleep coupled with an automated analysis by machine learning is appropriate for OSA diagnosis. Design, Setting, and Participants: Diagnostic study of adults undergoing overnight in-laboratory polysomnography (PSG) as the reference method compared with simultaneous MM monitoring at a sleep clinic in an academic institution (Sleep Laboratory, Centre Hospitalier Universitaire Université Catholique de Louvain Namur Site Sainte-Elisabeth, Namur, Belgium). Patients with suspected OSA were enrolled from July 5, 2017, to October 31, 2018. Main Outcomes and Measures: Obstructive sleep apnea diagnosis required either evoking signs or symptoms or related medical or psychiatric comorbidities coupled with a PSG-derived respiratory disturbance index (PSG-RDI) of at least 5 events/h. A PSG-RDI of at least 15 events/h satisfied the diagnosis criteria even in the absence of associated symptoms or comorbidities. Patients who did not meet these criteria were classified as not having OSA. Agreement analysis and diagnostic performance were assessed by Bland-Altman plot comparing PSG-RDI and the Sunrise system RDI (Sr-RDI) with diagnosis threshold optimization via receiver operating characteristic curves, allowing for evaluation of the device sensitivity and specificity in detecting OSA at 5 events/h and 15 events/h. Results: Among 376 consecutive adults with suspected OSA, the mean (SD) age was 49.7 (13.2) years, the mean (SD) body mass index was 31.0 (7.1), and 207 (55.1%) were men. Reliable agreement was found between PSG-RDI and Sr-RDI in patients without OSA (n = 46; mean difference, 1.31; 95% CI, -1.05 to 3.66 events/h) and in patients with OSA with a PSG-RDI of at least 5 events/h with symptoms (n = 107; mean difference, -0.69; 95% CI, -3.77 to 2.38 events/h). An Sr-RDI underestimation of -11.74 (95% CI, -20.83 to -2.67) events/h in patients with OSA with a PSG-RDI of at least 15 events/h was detected and corrected by optimization of the Sunrise system diagnostic threshold. The Sr-RDI showed diagnostic capability, with areas under the receiver operating characteristic curve of 0.95 (95% CI, 0.92-0.96) and 0.93 (95% CI, 0.90-0.93) for corresponding PSG-RDIs of 5 events/h and 15 events/h, respectively. At the 2 optimal cutoffs of 7.63 events/h and 12.65 events/h, Sr-RDI had accuracy of 0.92 (95% CI, 0.90-0.94) and 0.88 (95% CI, 0.86-0.90) as well as posttest probabilities of 0.99 (95% CI, 0.99-0.99) and 0.89 (95% CI, 0.88-0.91) at PSG-RDIs of at least 5 events/h and at least 15 events/h, respectively, corresponding to positive likelihood ratios of 14.86 (95% CI, 9.86-30.12) and 5.63 (95% CI, 4.92-7.27), respectively. Conclusions and Relevance: Automatic analysis of MM patterns provided reliable performance in RDI calculation. The use of this index in OSA diagnosis appears to be promising.

Assessment of the reliability of radiographic signs on panoramic radiographs to determine the relationship between mandibular third molars and the inferior alveolar canal.

OBJECTIVE: To assess the reliability of radiographic signs of the relationship between impacted mandibular third molars (IMTMs) and the inferior alveolar canal (IAC), and the vertical relationship between IMTM and IAC on panoramic radiographs (PRs) as risk indicators for IAC exposure during extraction. STUDY DESIGN: Seven radiographic signs regarding the appearance of roots and the IAC were assessed as present or absent on PRs. The vertical relationship between IMTM and the IAC was divided into 3 levels. The correlation between radiographic data and IAC exposure during extraction was analyzed by using χ2 statistics and logistic regression analysis. RESULTS: In total, 198 IMTMs were examined. In 46 cases (23.2%), the IAC was exposed during extraction. Four radiographic signs-darkening of the root, narrowing of the root, narrowing of the IAC, and diversion of the IAC-were associated with IAC exposure (P < .05). Concurrence of 2 or more of 7 radiographic signs increased the risk of IAC exposure (P < .001). The vertical relationship between IMTM and the IAC was found to be a risk indicator for IAC exposure (P < .001). No significant correlation was found between IAC exposure and inferior alveolar nerve damage (P = .148). CONCLUSIONS: Panoramic radiography is useful for assessing the risk of IAC exposure during IMTM extraction.

Plain radiographs for the assessment of coronectomy: not always a case of black or white.

In recent years, coronectomy of impacted lower third molar teeth has become an increasingly popular alternative to removal. Traditionally, orthopantomograms of mandibular third molars have been used to indicate features that show that the tooth is in close proximity to, or in an intimate relation with, the inferior dental nerve. Some authors advocate coronectomy as opposed to surgical removal to reduce the risk of damage to the nerve. In our Trust during the last two years, there has been a noticeable increase in the prescription of coronectomy for the management of pericoronitis associated with mandibular third molars. The purpose of this study therefore was to examine the differences among clinicians in their assessment of the need for coronectomy using plain-view radiographs. An online survey was completed by 25 clinicians with different levels of experience from six units across the UK and Republic of Ireland. We found a wide variation in the number of coronectomies prescribed (intraclass correlation 2.67), and when prescribed, a lack of agreement about the radiographic feature that had influenced the decision. These judgments are not straightforward. They are, to some extent, subjective, and in certain cases may benefit from a team-led approach.

Ultrasound-Guided Inferior Alveolar Nerve Block in the Horse: Assessment of the Extraoral Approach in Cadavers.

Blinded techniques to desensitize the inferior alveolar nerve (IAN) include intraoral, angled, and vertical extraoral approaches with reported success rates of 100%, 73%, and 59%, respectively. It has not been determined whether an ultrasound-guided extraoral approach is feasible. Further, the fascicular nature of the inferior alveolar and lingual nerves of the horse has not been described. The objectives of this study were to describe a low-volume ultrasound-guided vertical extraoral inferior alveolar nerve block technique and to describe the fascicular nature of these nerves. An ultrasound-guided approach to the IAN was conducted with a microconvex transducer and an 18-G, 15-cm spinal needle using a solution containing iodinated-contrast and methylene blue dye. Accuracy was assessed by contrast visualized at the mandibular foramen on computed tomography (CT) and methylene blue dye staining of the nerves on gross dissection. Sections of inferior alveolar and lingual nerves were submitted for histological analysis. Assessment by CT and dissection determined success rates of 81.3% and 68.8%, respectively; 68.8% of injections had inadvertent methylene blue dye staining of the lingual nerve. Nerve histology revealed both the inferior alveolar and lingual nerves to be multifascicular in nature. Mean fascicle counts for the inferior alveolar and lingual nerves were 29 and 30.8, respectively. The technique is challenging and no more accurate than previously published blinded techniques. Any extraoral approach to the IAN is likely to also desensitize the lingual nerve.

[A PhD completed. Pre-surgical assessment of the mandibular body and canal using CBCT imaging.] / Serie: Hora est. Prechirurgisch onderzoek van mandibula en canalis mandibularis met CBCT-scans.

The aim of this study was to determine the accuracy of the pre-surgical assessment of the mandible using cone beam computed tomography (CBCT) images. For surgical procedures in the mandible, it is important to determine the position of the mandibular canal in order to avoid damage to the inferior alveolar nerve (IAN). The best method to investigate this nerve is with the help of panoramic reconstructed images combined with cross-sectional reconstructed images. To protect the IAN during treatment, this research indicates that a minimal safety zone of 1.13 mm is advisable. When distances were being measured, a larger exaggeration of reality was observed with small distances. It appears that (semi)automatic tracing methods of the mandibular canal still cannot be used in clinical practice. When a CBCT scan reveals a lingual position of the mandibular canal in combination with a narrowing of the mandibular canal at the contact point with the root of a third molar the risk of damaging the IAN increases. CBCT imaging should only be applied in specific cases.