Does Maxillomandibular Fixation Technique Affect Occlusion Quality in Segmental LeFort I Osteotomy?

BACKGROUND: Segmental maxillary osteotomies require precise occlusal control due to variability in individual segment positioning. The role of maxillomandibular fixation (MMF) technique on occlusal control has not been validated. PURPOSE: The purpose is to measure and compare the accuracy of occlusal positioning among MMF techniques. STUDY DESIGN, SETTING, SAMPLE: This was a double-blinded in vitro study on experiment models to simulate a 3-piece LeFort I osteotomy. The models were constricted posteriorly and expanded using 3 different MMF techniques and compared to the unaltered baseline occlusion. Based on sample size calculation, 32 separate attempts were made for each MMF technique. PREDICTOR VARIABLE: The predictor variable was MMF technique (brackets, MMF screws, and embrasure wires). MAIN OUTCOME VARIABLES: The primary outcome variable was the visual occlusal analysis score, a 1.00 to 4.00 continuous scale measuring the similarity of the achieved occlusion to the planned (control) occlusion assessed by an oral and maxillofacial surgeon and an orthodontist. High visual occlusal analysis score indicated greater occlusal accuracy, with 3.50 defined as the threshold for accuracy. The secondary outcome variable was the linear error of the achieved occlusion at the canine and first molar teeth, with lower error indicating greater accuracy. An a priori accuracy threshold of 0.5 mm was set for this variable. COVARIATES: None. ANALYSES: Kruskal-Wallis test with post hoc testing was used to analyze the difference in the outcome variables of interest. P value < .05 was considered statistically significant. RESULTS: Thirty-two attempts for each technique showed that brackets had higher VAOS than MMF screws and embrasure wires (median differences 1.49 and 0.48, P < .001), and had lower linear occlusal error (median differences 0.35 to 0.99 mm, P < .001). CONCLUSION AND RELEVANCE: MMF technique influences the quality of occlusal control, with greater visual rating scores and lower linear errors seen with brackets than with embrasure wires or MMF screws.

Does the Use of Botulinum Toxin in Treatment of Myofascial Pain Disorder of the Masseters and Temporalis Muscles Reduce Pain, Improve Function, or Enhance Quality of Life?

BACKGROUND: The efficacy of botulinum toxin for management of myofascial pain disorder (MPD) remains controversial. PURPOSE: The purpose was to determine if the use of onabotulinumtoxinA (onabotA) in patients with MPD reduces pain, improves function, or enhances quality of life (QoL). STUDY DESIGN, SETTING, AND SAMPLE: This is a multicenter, prospective, randomized, double-blinded, placebo-controlled clinical trial. Subjects with orofacial pain were screened for MPD as defined by the Diagnostic Criteria for Temporomandibular Disorders. PREDICTOR VARIABLE: The primary predictor variable was MPD treatment with random assignment to onabotA or placebo (saline). MAIN OUTCOME VARIABLE: The primary outcome variable was pain before treatment (T0) and at 1 month (T1) using a visual analog scale. Secondary outcome variables included pain at 2 months (T2) and 3 months (T3), maximal incisal opening (MIO), jaw function (jaw functional limitation scale), and QoL (Short Form 36) measured at T0, T1, T2, and T3. COVARIATES: Covariates included subject demographics, prior treatments, and temporomandibular joint signs/symptoms. ANALYSES: Descriptive and bivariate statistics included χ2 test, Fisher's exact test, or t-test. RESULTS: Seventy five subjects with a mean age of 37 (±11) and 35 (±12) years in the onabotA and placebo groups, respectively (P = .6). Females represented 32 (86%) and 29 (76%), respectively (P = .3). Mean visual analog scale pain score in the onabotA group was 58 (±15), 39 (±24), 38 (±23), and 38 (±20) at T0, T1, T2, and T3, respectively; and the placebo group was 54 (±14), 40 (±23), 34 (±20), and 36 (±22) at T0, T1, T2, and T3, respectively. There was no statistically significant difference in pain between groups at any time point (P = .36). There was no statistically significant difference between groups in MIO (P = .124), jaw function (P = .236), or QoL domains (P > .05) at any time point. Within-group improvement in pain was seen in both groups (P < .005). Within-group improvement in jaw function was seen in the onabotA (P = .007) and placebo (P = .005) groups. There was no within-group improvement in MIO or QoL with either group (P > .05). CONCLUSIONS: OnabotA and saline (placebo) injections both decrease pain and improve jaw function in subjects with MPD.

Immediate Inferior Alveolar Nerve Reconstruction With Ablative Mandibular Resection Results in Functional Sensory Recovery.

BACKGROUND: Ablative mandibular resection with sacrifice of the inferior alveolar nerve (IAN) results in loss of sensation and decreased quality of life. PURPOSE: The purpose of this study is to evaluate functional sensory recovery (FSR) of immediate IAN allograft reconstruction performed during ablative mandibular resection at 1 year following surgery. STUDY DESIGN, SETTING, SAMPLE: This is a single-center retrospective cohort study that included consecutive subjects who underwent mandibular resection with IAN discontinuity and used a nerve allograft of ≥40 mm. PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE: The primary predictor variable is the use of an immediate nerve allograft in mandibular reconstruction. MAIN OUTCOME VARIABLE(S): The main outcome variable is FSR at 1 year using the Medical Research Council Scale. COVARIATES: Covariates include subject age, sex, specific pathology, nerve gap length, and development of neuropathic pain. ANALYSES: Statistical analysis of comparison of neurosensory outcomes was measured by bivariate statistics, weighted values, repeated measures, analysis of variance, and McNemar test. RESULTS: The study sample was composed of 164 subjects, of whom 55 (33.5%) underwent nerve allograft reconstruction and 30 (18.3%) did not have nerve reconstruction. Seventy-nine subjects (48.2%) did not meet the inclusion criteria. In the entire nerve allograft group of 55 subjects, FSR was achieved in 80% at 1 year; however, in benign disease alone, 31 of 33 (94%) achieved FSR at 1 year. In the nonallograft group (all benign disease), only 2 of 30 (7%) achieved FSR at 1 year. The significant covariates were age and pathology. Benign pathologic resections were 5.2 times more likely to achieve FSR than malignancies, and all subjects ≤ 18 years of age achieved FSR. After adjusting for age, sex, pathology, nerve gap length, nerve allograft was significantly associated with achieving FSR at 1 year (adjusted odds ratio = 5.52, 95% confidence interval = (1.03, 29.51), P value = .045 < .05). CONCLUSION AND RELEVANCE: Immediate long-span IAN allograft reconstruction is effective in restoration of sensation with an overall 80% of subjects achieving FSR at 1 year, while benign disease resulted in 94% FSR at 1 year. Immediate IAN reconstruction should be considered with mandibular resection involving the IAN, especially for children and benign disease.

Exploring the relationship between the number of systematic reviews and quality of evidence: an orthognathic surgery-based study.

OBJECTIVE: We analyzed the quality and quantity of systematic reviews (SRs) of orthognathic surgery, the most frequently published topic in maxillofacial surgery. STUDY DESIGN: We searched the PubMed database for SRs of orthognathic surgery with no restriction on the language of publication date. We assessed the certainty of evidence presented according to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol and the Leiden Manifesto using the Grading of Recommendations Assessment, Development, and Evaluation approach. We analyzed the data using descriptive statistics, Pearson´s correlation test, and linear regression. RESULTS: Of the 171 SRs evaluated, approximately one fifth presented evidence with a high level of certainty. The number of orthognathic surgery SRs has been increasing, and many SRs were published after very similar topics had already been published. There is no relationship between the impact factor and the certainty of evidence. CONCLUSIONS: An excessive number of SRs of orthognathic surgery are published, and many SRs are superfluous, simply reporting previous findings. Clinicians should not base treatment decisions solely on the evidence presented in SRs, and journal editors and reviewers should evaluate these SRs more critically, particularly when they address topics that have already been covered in the literature.

Predictability of single versus double-barrel vascularized fibula flaps and dental implants in mandibular reconstructions: A systematic review and meta-analysis of prospective studies.

STATEMENT OF PROBLEM: Patients with vascularized bone flaps from the fibula have reduced bone height, in which case a higher prosthetic abutment is needed for their implant-supported prosthesis. Although the double-flap technique seems promising, systematic reviews and meta-analyses of prospective studies are lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the grafted areas of single barrel fibular flaps (SBFF) and double-barrel fibular flaps (DBFF) by considering failure rates, dental implant complications, and bone union at the osteotomy sites. MATERIAL AND METHODS: A systematic review and meta-analysis was performed in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement, population, intervention, control, and outcomes (PICO) question, and the National Health and Medical Research Council scales. The event rate of complications and failures was calculated with a confidence interval (CI) of 95%. RESULTS: A total of 13 prospective studies with 441 participants and 330 graft sites were identified. A total of 235 participants had SBFF with 445 implants, and 95 had DBFF with 164 implants. The overall combined graft failure rates were 4.2% for SBFF and 3.2% for DBFF. The complication rate was 10% for SBFF and 1.9% for DBFF. Implant failure was at 4.7% in the SBFF group and 3.4% in the DBFF group. CONCLUSIONS: Complication rates and implant failures were similar for SBFF and DBFF. Therefore, for long-term oral rehabilitation, both SBFF and DBFF are suitable procedures for mandibular reconstruction.

Does Immediate Long-Span Nerve Allograft Reconstruction Affect the Incidence of Chronic Postsurgical and Neuropathic Pain in the Reconstructed Mandible Following Resection for Benign and Malignant Disease.

BACKGROUND: Peripheral nerve injury can lead to chronic postsurgical pain (CPSP) and neuropathic pain following major surgery. PURPOSE: Determine in patients undergoing ablative mandibular operations with transection of the trigeminal nerve: do those who undergo immediate repair, when compared to those whose nerves are not repaired, have a decreased or increased risk for CPSP or post-traumatic trigeminal neuropathic pain (PTTNp)? STUDY DESIGN, SETTING, SAMPLE: A multisite, retrospective cohort of patients who underwent resection of the mandible for benign or malignant disease with either no repair or immediate repair of the intentionally transected trigeminal nerve with a long-span nerve allograft were analyzed for the presence or absence of CPSP and PTTNp at 6 months. PREDICTOR VARIABLE: The primary predictor was the immediate repair or no repair of the trigeminal nerve. MAIN OUTCOME VARIABLE: The primary outcome was the presence or absence of CPSP and PTTNp at 6 months postsurgery. COVARIATES: There were 13 covariate variables, including age, sex, ethnicity, nerve injury, type of PTTNp, malignant or benign pathology and subtypes of each, use of radiation or chemotherapy, treatment of transected nerve end, longest follow-up time, pain scale, and onset of pain. ANALYSES: Two-tailed Student's t test and Welch's t test were performed on mean scores and post hoc logistics and linear regression modeling were performed when indicated. The confidence level for statistical significance was P value <.05. RESULTS: There were 103 and 94 subjects in the immediate and no-repair groups, respectively. The incidence of CPSP in the no-repair group was 22.3% and PTTNp was 2.12%, while there was 3.8% CPSP and 0% PTTNp in the repair group, which was statistically significant (P = <.001). Logistic regression modeling showed a statistically significant inverse relationship between the immediate repair and the incidence of CPSP/PTTNp with an odds ratio of 0.43, 95% confidence interval 0.18 to 1.01, P = .05. Greater age, malignant pathology, and chemo/radiation treatments were covariates found more frequently in the no repair group. CONCLUSION AND RELEVANCE: Immediate repair of an intentionally transected trigeminal nerve with a long-span nerve allograft during resection of the mandible for both benign and malignant disease appears to reduce CPSP and possibly eliminate the development of PTTNp.

Which Factors Affect the Reduction Quality of Open Reduction Internal Fixation of Mandibular Subcondylar Fractures?

BACKGROUND: Open reduction internal fixation (ORIF) of mandibular subcondylar fractures (MSF) involves several variables that could affect decision making. There is insufficient data regarding factors influencing the outcomes of MSF ORIF. PURPOSE: The purpose of this study was to investigate factors associated with quality of bony reduction of MSF and occlusion, after ORIF. STUDY DESIGN, SETTING, AND SAMPLE: We designed a retrospective cohort study of consecutively treated subjects for MSF ORIF, ages 18 to 64 years, by University of Illinois' Department of Oral and Maxillofacial Surgery, between January 1, 2013, and January 26, 2021. PREDICTOR VARIABLE: The primary predictor variable was the vertical level of MSF from the gonial angle. Secondary predictor variables included surgeon, fixation scheme (number and configuration of miniplate), surgical approach, time to surgery, mechanism of injury, vertical fragment overlap, overlying soft tissue thickness, presence of other mandibular fractures, and severity and direction of displacement. MAIN OUTCOME VARIABLES: The primary outcome variable was the mean radiographic reduction score (RRS), rated by 2 blinded observers on a 1 to 5 scale. The secondary outcome variable was presence of postoperative malocclusion as documented in the medical records. COVARIATES: Covariates were age and sex. ANALYSES: Descriptive statistics were computed. To investigate the influence of the predictor variables on reduction quality, multifactorial analysis of variance with post hoc Tukey test was performed. For malocclusion, χ2 test was performed. The level of significance was set at P < .05. RESULTS: Thirty-eight MSF in 37 subjects were included. Mean age was 32.7 years (range 18 to 64), and 83.8% were male. Mean RRS was 4.38 (standard deviation 0.77). Fixation scheme was the only variable that showed significant impact on RRS: single-straight miniplate had lower scores than double-straight (-1.50, P = .011), rhomboid (-1.29, P = .036), and ladder miniplates (-1.38, P = .048). There was 1 incidence of malocclusion (2.7%) which resolved without intervention. CONCLUSIONS AND RELEVANCE: Favorable reduction (anatomic reduction to mild discrepancies) can be achieved without malocclusion using double-straight, or rhomboid-shaped or ladder-shaped miniplates, without influences from patient or injury-related factors. In contrast, single-straight miniplate fixation resulted in moderate discrepancies in reduction, although it did not lead to malocclusion.

Novel Machine Learning Algorithms for Prediction of Treatment Decisions in Adult Patients With Class III Malocclusion.

BACKGROUND: Management of Class III (Cl III) dentoskeletal phenotype is often expert-driven. PURPOSE: The aim is to identify critical morphological features in postcircumpubertal Cl III treatment and appraise the predictive ability of innovative machine learning (ML) algorithms for adult Cl III malocclusion treatment planning. STUDY DESIGN: The Orthodontics Department at the University of Illinois Chicago undertook a retrospective cross-sectional study analyzing Cl III malocclusion cases (2003-2020) through dental records and pretreatment lateral cephalograms. PREDICTOR: Forty features were identified through a literature review and gathered from pretreatment records, serving as ML model inputs. Eight ML models were trained to predict the best treatment for adult Cl III malocclusion. OUTCOME VARIABLE: Predictive accuracy, sensitivity, and specificity of the models, along with the highest-contributing features, were evaluated for performance assessment. COVARIATES: Demographic covariates, including age, gender, race, and ethnicity, were assessed. Inclusion criteria targeted patients with cervical vertebral maturation stage 4 or above. Operative covariates such as tooth extraction and types of orthognathic surgical maneuvers were also analyzed. ANALYSES: Demographic characteristics of the camouflage and surgical study groups were described statistically. Shapiro-Wilk Normality test was employed to check data distribution. Differences in means between groups were evaluated using parametric and nonparametric independent sample tests, with statistical significance set at <0.05. RESULTS: The study involved 182 participants; 65 underwent camouflage mechanotherapy, and 117 received orthognathic surgery. No statistical differences were found in demographic characteristics between the two groups (P > .05). Extreme values of pretreatment parameters suggested a surgical approach. Artificial neural network algorithms predicted treatment approach with 91% accuracy, while the Extreme Gradient Boosting model achieved 93% accuracy after recursive feature elimination optimization. The Extreme Gradient Boosting model highlighted Wit's appraisal, anterior overjet, and Mx/Md ratio as key predictors. CONCLUSIONS: The research identified significant cephalometric differences between Cl III adults requiring orthodontic camouflage or surgery. A 93% accurate artificial intelligence model was formulated based on these insights, highlighting the potential role of artificial intelligence and ML as adjunct tools in orthodontic diagnosis and treatment planning. This may assist in minimizing clinician subjectivity in borderline cases.

What Do I Do if There is No Distal Nerve Stump for Inferior Alveolar Nerve Reconstruction?

This technical note describes an innovation that addresses a clinical problem in inferior alveolar nerve (IAN) reconstruction. In some cases of mandibular resection, there is a need to resect a significant amount of the IAN along with the pathologic lesion and this may result in a lack of a distal nerve stump for completion of the neural anastomosis. This technical note offers the option to perform the distal neurorrhaphy into the residual soft tissues with the expectation that axonal sprouting will occur and result in lower lip and chin sensory reinnervation. There are no inherent risks or additional costs. The significance of this technique is that it permits IAN reconstruction in cases where the actual nerve stump is not available and improves patient care. There should be no challenges or delays to implementing this innovation for surgeons who reconstruct the IAN during ablative mandibular resection.

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

PURPOSE: 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? MATERIALS AND METHODS: 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 40 years with 1-year-cycles on a 40-year-old model patient with persistent inferior alveolar or lingual nerve injury (S0 to S2+) at 3 months 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. RESULTS: 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. CONCLUSION: 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.

What Is the Linear Accuracy of Regional Voxel-Based Registration for Orthognathic Surgery Landmarks?

PURPOSE: While regional voxel-based registration (R-VBR) has been shown to have excellent reproducibility and angular accuracy, there are limited data on the linear accuracy of R-VBR for common orthognathic surgery landmarks, or on whether angular accuracy correlates with linear accuracy. The purpose of this study was to estimate the linear accuracy of R-VBR for several skeletal landmarks commonly used in orthognathic surgical planning, and to measure the correlation between angular and linear discrepancies. MATERIALS AND METHODS: This is a retrospective cross-sectional study of consecutive patients treated at a single center with nonsegmental LeFort I and bilateral sagittal split osteotomy surgery from January 2019 to November 2020. Cone beam computed tomography at the preoperative (T0) and immediate postoperative (T1) stages were analyzed to measure the postoperative positional changes of 11 orthognathic landmarks in 4 regions of interest (ROI) using R-VBR performed twice by two examiners. Pairwise correlation analysis and canonical correlation analysis were performed for the angular discrepancies (primary predictor variable) and the linear discrepancies (primary outcome variable) to measure the correlation between the two. RESULTS: In cone beam computed tomography analysis of 28 eligible subjects (16 males, 12 females; mean age 18.9 years, range 15 to 25), the mean absolute (MA) angular discrepancies ranged from 0.15° to 0.55°, while the corresponding MA linear discrepancies ranged from 0.05 to 0.41 mm. There was a strong correlation between angular and linear discrepancies that was statistically significant (P = .001 to .04, Spearman's rank correlation coefficient 0.38 to 0.87). CONCLUSIONS: For nonsegmental LeFort I osteotomies and bilateral sagittal split osteotomy, R-VBR has excellent linear accuracy within a single voxel size (0.3 mm) for commonly used orthognathic landmarks in the maxillary and distal mandibular ROI. The MA linear discrepancy for the proximal mandibular segment ROI was greater than a single voxel size, with a maximum of 0.41 mm.

Should orthognathic surgery be performed in growing patients? A scoping review.

The aim of this study was to determine whether the benefits of orthognathic surgery in a growing individual outweigh its risks. A scoping review was performed according to the PRISMA-ScR guideline. A bibliographic search from MEDLINE, Cochrane Library and LILACS was conducted until February 1, 2022. Scientific publications which reported orthognathic surgery in individuals under 18 years of age were considered. Inclusion criteria were performed according to PICOS model: do individuals with dentofacial deformity submitted to orthognathic surgery with an immature skeleton other than waiting growth cessation have overall benefits over any possible pos-operative consequences? Predictor of interest was growth status and outcome variables were positive benefits or negative consequences related to orthognathic surgery. Two reviewers screened records independently, and any disagreement between them was resolved by a third reviewer. Eligible studies were compiled into an extraction data form and were verified for validity and reliability. Risk of bias between studies was carried out using Review Manager. A total of 15 articles were included in this scoping review, comprising retrospective studies (9), case reports (3), and surveys (3). The topics covered varied from assessment of the functional needs, role, quality of life after orthognathic surgery, impact on growth, relation with temporomandibular joint surgical treatments, minimal referral age for surgery by orthodontists and complex cranio-maxillofacial deformities. Due to the heterogeneity of the articles, it was not possible to perform a meta-analysis. Within the limitations of the study it seems that the existing evidence seems favorable towards the intervention, improving quality of life in growing individuals, even at the risk of a second surgery.

Do We Need Safety Nets for Outsourced Computer-Aided Orthognathic Planning? A Two-Center Analysis.

PURPOSE: While the accuracy, cost-effectiveness, and time-efficiency of computer-aided orthognathic surgical planning (CAOP) have been studied, little is known about the influence of logistical factors of outsourced CAOP (OS-CAOP) on patient care. The purpose of this study was to investigate the limitations of OS-CAOP and their effect on treatment planning workflow and surgical outcomes. METHODS: A retrospective cross-sectional study was designed involving subjects who had undergone orthognathic surgery using CAOP from 2 academic oral and maxillofacial surgery centers in South Korea (Kyungpook National University, KNU) and the United States (University of Illinois Chicago, UIC) over an 8-year period. The primary predictor variable was use of modifications or alternatives to OS-CAOP. The primary outcome variable was the frequency of planning changes due to reasons that may have affected outcomes. Covariates included age and sex. Descriptive statistics was used, in addition to a chi-square test to analyze differences among categorical variables. RESULTS: Of a total of 642 eligible subjects in both centers, 5.8% used alternatives to OS-CAOP. 78.4% of these were due to reasons that may have affected outcomes (P < .001), representing 4.5% of all cases. The frequency of the need for OS-CAOP alternatives was identical in both centers (5.8%), but the specific reasons varied, with KNU having mostly plan-related changes (38.1% of alternatives), and UIC with more access and education-related reasons (68.8% of alternatives). At KNU, 71.4% of all alternatives were by repeat OS-CAOP, whereas at UIC, all were by in-house CAOP (IH-CAOP). CONCLUSIONS: In 2 major academic oral and maxillofacial surgery centers in South Korea and the United States, a substantial portion of OS-CAOP required pre-surgical modification, or use of alternatives. Most of the changes were for reasons that could potentially impact outcomes, prompting the need to consider establishing a "safety net" plan compatible with individual clinician's practice setting and healthcare system.

Reproducibility of a three-dimensional skeletal-based craniofacial orientation method for virtual surgical planning.

Inadequate craniofacial orientation of computed tomography (CT) scans can have significant implications in all three planes of space. The purpose of this study was to present the reproducibility of a 3-dimensional skeletal-based method of craniofacial orientation for virtual surgical planning. The protocol was defined by landmarks commonly used for cephalometry, and required identification of basion, nasion, right porion, and right orbitale, and navigation in all CT views (coronal, sagittal, and axial) for correction of yaw, roll, and pitch. Reproducibility of the method was assessed using eight CT scans that were randomly selected and anonymised. The observer group consisted of six oral and maxillofacial surgeons with varying levels of experience (resident or faculty) who performed craniofacial orientation according to the proposed method. Results were expected to be below 2° of variation, when overall accuracy as well as the influence of the academic level of the observers and symmetry of the evaluated anatomy, were considered as independent variables. Overall accuracy for all cases and for yaw, roll, and pitch were always below 2° of variation, without influence of level of experience and symmetry. Interobserver assessment was categorised as excellent in all instances, and intraobserver evaluation demonstrated consistency in the orientation of all axes. The proposed craniofacial orientation protocol presented in this study is easy to learn, applicable to computer-aided surgical planning, and can be performed by the non-technical clinician, resulting in excellent reproducibility and consistency.

The Opioid Analgesic Reduction Study (OARS)-a comparison of opioid vs. non-opioid combination analgesics for management of post-surgical pain: a double-blind randomized clinical trial.

BACKGROUND: Everyday people die unnecessarily from opioid overdose-related addiction. Dentists are among the leading prescribers of opioid analgesics. Opioid-seeking behaviors have been linked to receipt of initial opioid prescriptions following the common dental procedure of third molar extraction. With each opioid prescription, a patient's risk for opioid misuse or abuse increases. With an estimated 56 million tablets of 5 mg hydrocodone annually prescribed after third molar extractions in the USA, 3.5 million young adults may be unnecessarily exposed to opioids by dentists who are inadvertently increasing their patient's risk for addiction. METHODS: A double-blind, stratified randomized, multi-center clinical trial has been designed to evaluate whether a combination of over-the-counter non-opioid-containing analgesics is not inferior to the most prescribed opioid analgesic. The impacted 3rd molar extraction model is being used due to the predictable severity of the post-operative pain and generalizability of results. Within each site/clinic and gender type (male/female), patients are randomized to receive either OPIOID (hydrocodone/acetaminophen 5/300 mg) or NON-OPIOID (ibuprofen/acetaminophen 400/500 mg). Outcome data include pain levels, adverse events, overall patient satisfaction, ability to sleep, and ability to perform daily functions. To develop clinical guidelines and a clinical decision-making tool, pain management, extraction difficulty, and the number of tablets taken are being collected, enabling an experimental decision-making tool to be developed. DISCUSSION: The proposed methods address the shortcomings of other analgesic studies. Although prior studies have tested short-term effects of single doses of pain medications, patients and their dentists are interested in managing pain for the entire post-operative period, not just the first 12 h. After surgery, patients expect to be able to perform normal daily functions without feeling nauseous or dizzy and they desire a restful sleep at night. Parents of young people are concerned with the risks of opioid use and misuse, related either to treatments received or to subsequent use of leftover pills. Upon successful completion of this clinical trial, dentists, patients, and their families will be better able to make informed decisions regarding post-operative pain management. TRIAL REGISTRATION: ClinicalTrials.gov NCT04452344 . Registered on June 20, 2020.

NG2/CSPG4 regulates cartilage degeneration during TMJ osteoarthritis.

Changes in the mechanical homeostasis of the temporomandibular joint (TMJ) can lead to the initiation and progression of degenerative arthropathies such as osteoarthritis (OA). Cells sense and engage with their mechanical microenvironment through interactions with the extracellular matrix. In the mandibular condylar cartilage, the pericellular microenvironment is composed of type VI collagen. NG2/CSPG4 is a transmembrane proteoglycan that binds with type VI collagen, and has been implicated in the cell stress response through mechanical loading-sensitive signaling networks including ERK 1/2. The objective of this study is to define the role of NG2/CSPG4 in the initiation and progression of TMJ OA and to determine if NG2/CSPG4 engages ERK 1/2 in a mechanical loading dependent manner. In vivo, we induced TMJ OA in control and NG2/CSPG4 knockout mice using a surgical destabilization approach. In control mice, NG2/CSPG4 is depleted during the early stages of TMJ OA and NG2/CSPG4 knockout mice have more severe cartilage degeneration, elevated expression of key OA proteases, and suppression of OA matrix synthesis genes. In vitro, we characterized the transcriptome and protein from control and NG2/CSPG4 knockout cells and found significant dysregulation of the ERK 1/2 signaling axis. To characterize the mechanobiological response of NG2/CSPG4, we applied mechanical loads on cell-agarose-collagen scaffolds using a compression bioreactor and illustrate that NG2/CSPG4 knockout cells fail to mechanically activate ERK 1/2 and are associated with changes in the expression of the same key OA biomarkers measured in vivo. Together, these findings implicate NG2/CSPG4 in the mechanical homeostasis of TMJ cartilage and in the progression of degenerative arthropathies including OA.

What Do We Know Beyond Reliability in Voxel-Based Registration? Validation of the Accuracy of Regional Voxel-Based Registration (R-VBR) Techniques for Orthognathic Surgery Analysis.

PURPOSE: Despite having excellent reproducibility, the accuracy of regional voxel-based registration (R-VBR) techniques used for postoperative orthognathic surgical analysis has not been validated. The purpose of this study was to validate the accuracy of R-VBR. METHODS: Preoperative (T0) and postoperative (T1) cone beam computed tomography (CBCT) of consecutive patients treated at a single center with nonsegmental LeFort I and bilateral sagittal split osteotomy were included. T1 CBCTs were oriented to match that of the standardized T0, and thus were assigned a known rotational transformation matrix in pitch/roll/yaw (P/R/Y), to create T1-prime (T1'). A copy of T1 (cT1) was made and was superimposed to T1' using R-VBR for 4 regions of interest (ROI): maxilla, distal mandible, right proximal mandible, and left proximal mandible, to create cT1'. The transformation matrix for each of the ROI was compared to those of T1' using paired t test and Bland-Altman analysis. RESULTS: Twenty-eight eligible subjects' CBCTs were analyzed. Mean difference between T1' and cT1' ranged from -0.08 to 0.14° (maximum 0.73°), with no statistically significant differences (P = 0.216 to 1). Mean absolute difference ranged from 0.13 to 0.31° (maximum 0.73°). Bland-Altman analysis showed good agreement between T1' and cT1', indicating excellent accuracy. CONCLUSIONS: R-VBR using the maxilla, distal mandible, and the bilateral proximal mandibular segments as ROI has excellent accuracy in terms of rotational measurements.