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Trismus is one of the most debilitating and treatment-resistant complications resulting from head and neck oncological treatments. The objective of this study was to assess how primary tumour variables could assist in predicting chronic trismus. From a (retrospective) oncological database (Department of Oral and Maxillofacial Surgery, University Hospitals Leuven), tumour-related, surgical, and oral functional variables were reviewed. Contributing factors for chronic trismus, defined as a mouth opening of less than 35 mm, at least one year after treatment for oral squamous cell cancer, were assessed via logistic regression. A mediational analysis was conducted on the significant predictive variables. Thirteen out of 52 patients were observed to have chronic trismus. A significantly higher prevalence of trismus was found for increasing clinical T classification (p0.01), tumours based in the maxilla or the retromolar trigone (p = 0.04), after adjuvant radiotherapy (p = 0.04), and/or with masticatory muscle tumour invasion (p ≤ 0.02). Furthermore, radiotherapy significantly impacted T classification in chronic trismus, while T classification was significantly related to masticatory muscle invasion. Although radiotherapy and clinical T classification are well-established risk factors for postoperative trismus, masticatory muscle invasion should be considered as one of the main predictive factors.

Academic impairment in individuals with attention-deficit/hyperactivity disorder (ADHD) is in part due to reduced motivation for academic tasks, which is likely to vary as a function of task characteristics. The current study employed a new questionnaire—the Child and Adolescent Motivational Profile (CHAMP)—to examine; (1) which task characteristic participants with ADHD perceive as most motivating relative to typically developing peers (TDP) and (2) whether these differences mediate academic functioning. 34 participants with ADHD and 435 TDP (8–16 years) completed the CHAMP. Academic achievement (grade point average) and self-reported positive/negative classroom experiences were recorded. No task characteristics were rated higher in terms of their motivational salience in the ADHD group than in the control sample. Marked/graded, Socially evaluated, Collaborative, Requiring focus and Cognitively challenging task characteristics were rated significantly lower by the ADHD group than controls. The lower rating of Socially evaluated was explained by comorbid ODD symptoms. Cognitively challenging was rated as particularly unmotivating by individuals with ADHD. ADHD was associated with a decreased GPA and a more negative classroom experience. The associations between ADHD and GPA/negative classroom experience were both partially mediated by scores on the Cognitively Challenging scale. For children and adolescents with ADHD tasks that are cognitively challenging were not particularly motivating. To increase task motivation, and improve academic performance of individuals with ADHD, it may be important to include rewarded task elements as they are appraised as particularly motivating by these individuals and this appraisal was similar to that of TDP.

This study used a novel 3D analysis to longitudinally evaluate orthodontic tooth movement (OTM) and bone morphometry. Twelve-week-old male Wistar rats were subjected to OTM by applying a constant orthodontic force (OF) of 25cN between one of the upper first molars and a mini-screw. In vivo micro-CTs were taken before and after 10, 17, 24 and 31 days of force application, and superimposed by a novel and rigid voxel-based registration method. Then the tooth and alveolar bone segment at different time points became comparable in the same coordinate system, which facilitated the analysis of their dynamic changes in 3D. By comparison between time points and between OF and no OF sides, this study showed that the OTM rate was not constant through time, but conformed to a ‘V’ shape changing pattern. Besides, OF induced displacement of both loaded and unloaded teeth, and the latter mirrored the former in a delayed manner. In addition, bone morphometric changes synchronized with OTM rate changes, implying that a higher OTM rate was concomitant with more alveolar bone loss. The pressure and tension areas might not be in two opposite sides, but actually adjacent and connected. These findings might provide instructive evidence for both clinical, translational and basic research in orthodontics.

Comorbidities influence treatment outcome of oral squamous cell carcinoma (OSCC). This study compared the predictive performance of six comorbidity scales for overall survival after surgery for OSCC.We retrospectively analyzed OSCC patients, surgically treated at an academic center in Belgium between January 01, 2000 and January 01, 2020. Validity of the scales was evaluated using the area under the curve (AUC) of receiver operating characteristic curves.Three hundred and twenty three patients were included. Elixhauser Comorbidity Index (AUC = 0.74, 95% CI: 0.55-0.92; AUC = 0.73, 95% CI: 0.55-0.80), modified Elixhauser Comorbidity Index (AUC = 0.72, 95% CI: 0.54-0.91; AUC = 0.69, 95% CI: 0.51-0.77), and Combined Comorbidity Index (AUC = 0.76, 95% CI: 0.58-0.84; AUC = 0.76, 95% CI: 0.59-0.84) were meaningful predictors for 2 and 5-year survival, respectively.Selected comorbidity scales were capable of predicting overall survival for OSCC patients 2 and 5 years after primary surgery.

This study aims (1) to test the reliability of split-mouth models in rats for the study of orthodontic tooth movement (OTM) and (2) to propose an improved 3D model for quantification of OTM in rats. Eleven adult male Wistar rats were randomly assigned to two groups. In Group 1 (n=5) dental anchorage was used by applying a constant orthodontic force (OF) of 25 cN through a Sentalloy closed coil spring between the upper incisors and the first maxillary molar (M1), while no OF was applied on the contralateral hemimaxilla. In Group 2 (n=6) skeletal anchorage was used by applying the same OF between M1 and a miniscrew on one hemimaxilla, while no OF was applied on the contralateral side. All rats were scanned in vivo right before (baseline, T0) and after 31 days (T1) of OF using micro-CT. OTM was compared between time points and between experimental sides in both groups using conventional 2D analysis and a novel 3D model. Using incisors as anchorage results in their distal displacement in both OF and no OF sides. In the OF side, movement of M1 is underestimated by incisor displacement. Mesial displacement of M1 was found in the no OF side of all groups at T1, which confirms that split mouth designs are not applicable for orthodontic research on OTM in rats. The new 3D model yielded higher sensitivity for measurement of tooth displacement in planes other than the sagittal, and incisor displacement was reduced by using skeletal anchorage.

BACKGROUND: A combination of short titanium plates fabricated using additive manufacturing (AM) provides multiple advantages for complete mandible reconstruction, such as the minimisation of inherent implant deformation formed during AM and the resulting clinical impact, as well as greater flexibility for surgical operation. However, the biomechanical feasibility of this strategy is still unclear, and therefore needs to be explored. METHOD: Three different combinations of short mandible reconstruction plates (MRPs) were customised considering implant deformation during the AM process. The resulting biomechanical performance was analysed by finite element analysis (FEA) and compared to a conventional single long MRP. RESULTS: The combination of a long plate and a short plate (Design 3 [LL61 mm/RL166 mm]) shows superior biomechanical properties to the conventional single long plate (Design 1 [TL246 mm]) and reveals the most reliable fixation stability among the three designs with short plates. Compared to conventional Design 1, Design 3 provides higher plate safety (maximum tensile stress on plates reduced by 6.3%), lower system fixation instability (relative total displacement reduced by 41.4%), and good bone segment stability (bone segment dislocation below 42.1 μm) under masticatory activities. CONCLUSIONS: Preclinical evidence supports the biomechanical feasibility of using short MRPs for complete mandible reconstruction. Furthermore, the results could also provide valuable information when treating other large-sized bone defects using short customised implants, expanding the potential of AM for use in implant applications. ispartof: Computers In Biology And Medicine vol:139 ispartof: location:United States status: Published online

This study aims to evaluate the use of customized surgical plates in patients with mandibular defects concerning postoperative aesthetics and functional outcomes during the 2-year follow-up. Preoperative virtual surgical plans and patient-specific three-dimensional printed plates were tailored for consecutive patients. Preoperative preparation, surgical produces, postoperative aesthetics, and functional outcomes were described in detail. The average follow-up period was over 2 years. In the presented clinical cases, aesthetic and functional outcomes were reported to be satisfactory.

ObjectiveThe treatment approach of recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) has long been similar for all patients. Any difference in treatment strategy was only based on existing comorbidities and on preferences of the patient and the treating oncologist. The recent advance obtained with immune therapy and more specifically immune checkpoint blockade (ICB) has been a true game changer. Today, patients and physicians have a choice to omit chemotherapy. In a small subset of patients, ICB induces a very durable disease control. The subgroup of patients in which ICB without chemotherapy would be the preferential approach is still ill-defined. Yet, this evolution marks a major step towards a more personalized medicine in R/M HNSCC.Materials and MethodsIn this paper, we present a retrospective cohort study of a patient population that was treated with ICB in a single center and we analyze potential factors that are associated with outcome and may help to select patients for treatment with ICB.Results137 consecutively treated patients were identified. Male gender and metastatic disease appeared to be associated with improved overall survival (OS). There was no correlation observed with age, number of previous treatment lines or immune target.ConclusionAlong with PD-L1 status defined by Combined Positive Score (CPS), clinical parameters such as site of recurrence and gender may help to define the optimal treatment strategy in R/M HNSCC.

OBJECTIVE To investigate the relationship between preoperative trabecular bone structure and implant outcome based on bone morphometric bone parameters from CBCT scans. MATERIALS AND METHODS Twenty consecutive cases with early implant failure in the posterior region of the mandible were matched with 20 control patients with a successful implant osseointegration selected. All patients had taken a preoperative CBCT image according to a standardized acquisition protocol. On these CBCT scans, the trabecular bone of each implantation site was selected and segmented, after which 3D morphometric bone parameters were calculated and used in a cluster analysis to objectively differentiate trabecular bone patterns. Fisher's exact test was used to determine whether there is a significant association between trabecular pattern and implant outcome. RESULTS A sparse, intermediate, and dense trabecular bone pattern was distinguished by cluster analysis. The relationship between the trabecular bone pattern and early implant failure was significant (z = 9.6; p

Aim The aim of the study was to evaluate whether the use of a xenograft is not inferior to the use of xenograft and autogenous bone chips in treating dehiscences at implant placement. Materials and methods After implant placement, leaving a dehiscence, control sites were treated using a composite graft (autogenous bone chips and xenograft) and at the test sites 100% xenograft was used. Both sites were covered with a resorbable collagen membrane. Dehiscences were measured clinically at implant placement and at re-entry. CBCT was taken immediately after implant placement and after 4 months. Results In total, 28 GBR procedures were performed in 14 patients. On average, the change in vertical defect height was 2.07 mm (46.7%-test group) and 2.28 mm (50.9%-control group) (p > .05). The horizontal defect width at the implant shoulder change on average 1.85 mm (40.5%-test group) and 1.75 mm (40.9%-control group) (p > .05). On average, a loss in augmentation thickness of 0.45 mm (68.9%-test group) and 0.64 mm (55.5% control group) between implant placement and augmentation and abutment surgery was obtained at the implant shoulder. Conclusion Both treatment modalities seem to work to a certain extent. At implant shoulder level, the augmentation thickness seems to be disappeared after the healing phase. (NCT03946020).

Objectives To evaluate the peri-implant trabecular bone volume and architecture changes with 6-month follow-up after local application of platelet-rich plasma (PRP) and platelet-poor plasma (PPP) using high-resolution micro-CT. Material and methods Seventy-two dental implants were placed into healed mandibular sites of 9 beagle dogs. Implants were randomly divided into 4 groups following a split-mouth design: control I; control II; PPP; and PRP. Primary and secondary stabilities were assessed using resonance frequency analyses. At 1, 3, and 6 months after implant loading, trabecular structural parameters were evaluated at 0.5, 1, and 1.5 mm away from implants using micro-CT (voxel = 20 μm). Results Primary and secondary stabilities were equivalent in all conditions. PPP and PRP groups showed higher bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) but lower trabecular separation (Tb.Sp) and total porosity percentage (Po (tot)) at all 3 time points. A significant decrease in BV/TV and Tb.Th was found for the control groups after 3 months of healing, while this was not observed in both the PPP and PRP groups. However, no distinct difference was found between the PRP and PPP groups over time. Moreover, as the investigated distance from the implant surface increased, BV/TV and Po (tot) within the same group and time point stayed the same, yet Tb.Th and Tb.Sp continued to increase. Conclusions Platelet-rich plasma and PPP with conventional implant placement lead to similar primary and secondary implant stability, but improved peri-implant bone volume and structural integration. The present research does not seem to suggest a different bone remodeling pattern when using PRP or PPP.

Recent magnetic resonance imaging (MRI) studies implicate structural alterations of amygdala, a brain region responsible for processing and experiencing negative emotions, in adolescents with attention-deficit/hyperactivity disorder (ADHD). Here we examined ADHD-related structural correlates of amygdala functional activity elicited during a functional MRI task designed to test behavioural and brain responses to the imposition of delay - an event known to both elicit amygdala hyperactivation and aversity in ADHD.Structural MRI scans from 28 right-handed male adolescents with combined type ADHD and 32 age-matched controls were analysed. Regional grey matter volumes of ADHD and control participants (ADHD was associated with significantly reduced volumes in bilateral amygdala, parahippocampal and temporal gyrus (We provide the first evidence of the functional significance of reduced amygdala volumes in adolescents with ADHD by highlighting its relation to delay-induced brain activity that is linked to delay aversion.

AIM: To evaluate dimensional changes in the alveolar ridge and bone structure after tooth extraction when L-PRF or A-PRF+ was used in comparison to unassisted socket healing. MATERIALS AND METHODS: Twenty patients in need of at least three tooth extractions in the aesthetic zone were included. L-PRF, A-PRF+ or control was randomly assigned, leaving one empty socket/edentulous site between conditions. CBCT scans were obtained immediately after tooth extraction and after 3 months of healing. Horizontal and vertical dimensional changes of the ridge and socket fill were calculated. Histological and micro-CT analysis of bone biopsies were used to evaluate post-surgical bone structural healing. RESULTS: Mean horizontal and vertical changes at 1-mm below the crest (buccal and palatal side) were similar for the three sites (p > 0.05). For the socket fill, L-PRF (85.2%) and A-PRF+ (83.8%) showed superior values than the control (67.9%). The histological and radiological analysis reported more newly formed bone for the PRF groups, without any significant differences between both. CONCLUSIONS: PRF matrices failed to reduce the dimensional changes after multiple tooth extractions in the premaxilla. After 3-month healing, both PRF matrices showed radiographically a significant superiority for the socket fill. Histologically, they seemed to accelerate new bone formation. ispartof: JOURNAL OF CLINICAL PERIODONTOLOGY vol:48 issue:7 pages:984-995 ispartof: location:United States status: published

e18027 Background: Response rates of immune checkpoint inhibitor (ICI) therapy for recurrent and/or metastatic head and neck squamous cell carcinoma (R/M HNSCC) are relatively low. This study evaluates the predictive and prognostic value of weight loss and changes in body composition prior to and during ICI therapy in R/M HNSCC. Methods: This retrospective multicenter cohort study enrolled ninety-eight patients. Patient, tumor and treatment characteristics were retrieved from health records, including neutrophil and platelet-lymphocyte-ratio (NLR and PLR). Cachexia was defined according to the international consensus (Fearon et al. 2011). Skeletal muscle (SM), subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) were evaluated on baseline and follow-up computed tomography scans at the third lumbar vertebrae level. Univariable and multivariable regression analysis were performed for six months progression free survival (PFS6m) and overall survival (OS). Results: Thirty-four patients (35%) experienced significant early weight loss (> 2%) during the first six weeks of therapy. This subgroup presented a significantly higher NLR and PLR at baseline. NLR and PLR were significantly correlated with VAT and SAT index. Independent predictors of PFS6m were lower world health organization performance status (WHO PS) (HR 0.16 [95% CI 0.04-0.54] p = 0.003), higher baseline SAT index (HR 1.045 [95% CI 1.02-1.08] p = 0.003), and early weight loss < 2% (HR 0.85 [95% CI 0.74-0.98] p = 0.03). WHO PS and baseline cachexia in combination with > 2% early weight loss were independent predictors of OS (HR 2.09 [95% CI 1.11-3.92] p = 0.02, HR 2.18 [95% CI 1.13-4.21] p = 0.02). Conclusions: The combination of cachexia at baseline and weight loss during the first six weeks of ICI therapy is associated with worse OS in HNSCC patients treated with ICI therapy. Patients with early weight loss during ICI treatment show an increase in systemic inflammation. The mechanism of how adipose tissue interferes with ICI response needs further investigation.

3D printing technique has been well developed in the past decades and it has been successfully applied in the medical field. For example, 3D printed medical models for pre-surgical evaluation, 3D printed surgical templates for hard tissue resection, and 3D printed patient specific implant in titanium or polyether ether ketone (PEEK) material. This chapter first introduces different 3D printing techniques and then it provides a general overview about 3D printed scaffold in bone regeneration. The key factures, which may influence the bone regeneration, are introduced, for example, pore size, pore structure, and surface treatment.

BackgroundThe objective of this systematic review was to identify the different surgical treatment modalities of severe trismus after head and neck squamous cell cancer treatment.MethodsAn electronic literature database search was conducted in Medline, Embase, Cochrane, Web of Science, and OpenGrey to determine articles published up to September 2021. Two observers independently assessed the identified papers for eligibility according to PRISMA guidelines. The inclusion criteria were trismus after head and neck squamous cell cancer with consecutive treatment, detailed description of the surgical procedure for trismus release, description of the initial treatment, at least 6 months between initial cancer treatment and trismus release surgery, a minimal follow-up (FU) of 6 months, and availability of full text. The quality was evaluated using the Newcastle-Ottawa scale. A subanalysis of the maximal mouth opening (MMO) was performed using a mixed-effect model.ResultsA total of 8,607 unique articles were screened for eligibility, 69 full texts were reviewed, and 3 studies, with a total of 46 cases, were selected based on the predetermined inclusion and exclusion criteria. Three treatment strategies were identified for trismus release (1) free flap reconstruction (FFR), (2) coronoidectomy (CN), and (3) myotomy (MT). There was a clear improvement for all treatment modalities. A quantitative analysis showed a beneficial effect of CN (mean 24.02 ± 15.02 mm) in comparison with FFR (mean 19.88 ± 13.97 mm) and MT (mean 18.38 ± 13.22 mm) (P < 0.01*). An increased gain in MMO after trismus release was found if no primary resection was performed (P = 0.014*). Two studies included in the analysis had an intermediate risk of bias and one had a low risk of bias.ConclusionCurrently available reports suggest a low threshold for performing a CN compared with FFR and MT. There is a need for high-quality randomized controlled trials with carefully selected and standardized outcome measures.

Fatigue fracture of titanium alloys fabricated by Selective Laser Melting (SLM) in engineering has been studied in recent years, but an underlying understanding of the in-vivo fatigue fracture of SLM-fabricated titanium patient-specific implants (PSIs) is rarely revealed due to the complex in-vivo biomechanical behaviour and biological environment combined. This paper provides a multidimensional and comprehensive analysis of the in-vivo fatigue failure mechanism of an SLM-fabricated Ti6Al4V mandible reconstruction plate, by macro-scaled Finite Element Analysis (FEA) of biomechanical behaviours, static force analysis and micro-scaled metallurgical investigation. FEA indicates maximal tensile stress of 392.6 MPa locally on the implant with high stress gradients around. Although the theoretical stress is far below the fatigue strength of SLM-fabricated Ti6Al4V material, indicating low potential of plate failure, the site with maximal stress and high stress gradients successfully determine the failure route of the plate, which coincides with the factual crack growth mode on the plate. The followed analysis of stress and force conditions theoretically confirms the failure condition on the implant. Metallurgical investigations further show β and α/α’ phases and tiny pores at implant (sub)surface, together with typical features (striations, cleavage facets and dimples) of metal fatigue failure in fractography analysis. Taken together these can conclude that the fatigue crack initiates from the implant surface subjected to surface defects and maximal stress caused by implant design, and propagates radially, showing a combined brittle/ductile fracture mode. The process is synergistically influenced by Ca/P/O deposits and hydrogen embrittlement under the biological environment. Practical measures for the improvement of in-vivo fatigue life of implants are finally provided.

Functional magnetic resonance imaging studies have reported a diminished response in the brain's reward circuits to contingent cues predicting future monetary gain in adolescents with attention-deficit/hyperactivity disorder (ADHD). The situation with regard to monetary loss is less clear, despite recognition that both positive and negative consequences impact ADHD behaviour. Here, we employ a new Escape Monetary Loss Incentive task in an MRI scanner, which allows the differentiation of contingency and valence effects during loss avoidance, to examine ADHD-related alterations in monetary loss processing. There was no evidence of atypical processing of contingent or non-contingent monetary loss cues in ADHD - either in terms of ratings of emotional and motivational significance or brain responses. This suggests that the ability to process contingencies between performance and negative outcomes is intact in ADHD and that individuals with ADHD are no more (or less) sensitive to negative outcomes than controls. This latter finding stands in stark contrast to recent evidence from a similar task of atypical emotion network recruitment (e.g. amygdala) in ADHD individuals to cues predicting another negative event, the imposition of delay, suggesting marked specificity in the way they respond to negative events. ispartof: SOCIAL COGNITIVE AND AFFECTIVE NEUROSCIENCE vol:17 issue:5 pages:482-492 ispartof: location:England status: published

Background Bone-to-implant contact ratio (BIC%) plays a critical role in secondary stability of osseointegrated dental implants. The aim of this study was to identify the correlation of 2D/3D micro-CT images with histology as a gold standard for evaluating BIC% and to investigate the influence of the platelet-rich plasma (PRP) and platelet-poor plasma (PPP) on 3D BIC% following delayed implant placement with delayed loading (DIP+DL). Methods Nine beagle dogs were recruited. Following bilateral extraction of mandibular 3rd premolar, 4th premolar, and 1st molar, 54 screw-type titanium implants were inserted and randomly divided into one control and two test groups based on a split-mouth design. The control group involved DIP+DL (n = 18) and both test groups included DIP+DL with local application of PRP (n = 18) and PPP (n = 18). A BIC analysis was performed utilizing 2D histomorphometry and 2D/3D micro-CT. Following identification of correlation between histology and 2D/3D micro-CT images, a 3D micro-CT assessment of the 3D BIC% at three follow-up time-points (1, 3, and 6 months) was carried out for observing the influence of PRP and PPP on BIC. Results The 2D micro-CT BIC% values revealed a strong positive correlation with histology (r = 0.98, p r = 0. 67, p = 0.005). BIC levels at 1 month and combined influence of PPP and PRP irrespective of time-points revealed significantly higher 3D BIC% compared to the control. However, a reduction in 3D BIC% was observed at the 3rd and 6th month. No significant difference was observed between both PRP and PPP. Conclusions Both 2D and 3D micro-CT demonstrated a potential to be utilized as a complimentary method for assessing BIC compared to the histological gold standard. Overall, both PRP and PPP significantly facilitated bone healing and osseointegration with a higher 3D BIC at follow-up. However, their influence was reduced as the observation period was increased.

Background and Objective While osseointegration following various dental implant placement protocols has been extensively investigated, the neurohistological integration has received little attention. The primary aim of this study was to compare the myelinated nerve fibers density in peri-implant bone tissue following various implant placement protocols. The secondary aim assessed the effect of follow-up on peri-implant nerve fibers density. Methods Ten beagle dogs randomly received 68 commercially pure titanium implants in the mandibular premolar or molar region bilaterally following extraction utilizing one of the six treatment protocols: (a) immediate implant placement (IIP) and immediate loading (IL); (b) IIP and delayed loading (DL); (c) IIP and left unloaded (UL); (d) delayed implant placement (DIP) and IL; (e) DIP and DL; and (f) DIP and UL. Histomorphometric analysis of the peri-implant myelinated nerve fibers was performed in a 300 mu m peri-implant zone at the cervical, middle, and apical level following implant placement. The follow-up assessment involved longitudinal observation at 3 months following each implant treatment protocol and at 6 months for IIP+IL and IIP+DL protocols. Results The influence of different treatment protocols, including the fixed effects of implant groups (IIP+IL, IIP+DL, IIP+UL, DIP+IL, DIP+DL, DIP+UL) and regions (cervical, middle, apical), was examined via a linear mixed model. The IIP+IL group showed a significantly higher myelinated nerve density compared to the IIP+UL and DIP+UL group. Peri-implant nerve re-innervation was significantly higher (P = .002) in the apical region compared to the cervical region. After immediate implant placement, the IL group showed a significantly (P = .03) higher density of myelinated nerve fibers compared to DL. No significant (P = .19) effect of follow-up on nerve density was observed. Conclusion The immediate implant placement and loading protocol showed most beneficial effect on peri-implant innervation with highest myelinated nerve density in the apical region. A longer loading time had no influence on the peri-implant nerve density. China Scholarship CouncilChina Scholarship Council [201708210187] Funding Source: Medline; Fonds Wetenschappelijk Onderzoek FWO[11.ZU.117N] Funding Source: Medline; National Natural Science [81370026] Funding Source: Medline Jacobs, R (corresponding author), Katholieke Univ Leuven, Dept Imaging & Pathol, OMFS IMPATH Res Grp, Campus Sint Rafael,Kapucijnenvoer 33, BE-3000 Leuven, Belgium. reinhilde.jacobs@kuleuven.be

Summary Introduction To date, there is a lack of evidence related to the long-term evaluation of recipient-site functional outcomes following mandibular reconstruction with vascularized bone grafts. Therefore, the aim of this systematic review and meta-analysis was to evaluate the long-term recipient-site functional outcomes in oral oncology patients who require mandibular reconstruction with either vascularized fibular flap (VFF) or vascularized iliac flap (VIF). Methods An extensive electronic search was conducted in PubMed, Web of Science, Cochrane, and Embase databases for identifying articles published until April 2020. All papers were dual screened for eligibility in accordance with the Preferred Reporting of Systematic Reviews and Meta-Analyses and Meta-analysis of Observational Studies in Epidemiology guidelines. The risk of bias was assessed using the MINORS tool. A meta-analysis of functional outcome parameters was performed to estimate single incidence rates. Results A total of 257 patients with a mean follow-up period of 38.6 ± 19.5 months were included in this meta-analysis, where 174 patients underwent VFF reconstruction and 83 patients involved reconstruction with VIF. The functional outcomes in patients reconstructed with VIF showed improved scoring for mastication, deglutition, diet, and speech. Speech showed highest score among all functional parameters, whereas, mastication was the most poorly recovered parameter in relation to reconstruction with both flaps. No significant difference in functional outcomes was observed between both flaps. Conclusion Current evidence seems to indicate that VIF offers improved long-term recipient-site functional outcomes. Yet, considering a high level of data heterogeneity in published studies, future long-term standardized comparative studies should be conducted.

PURPOSE: This study was performed to introduce an in vivo hybrid multimodality technique involving the coregistration of micro-computed tomography (micro-CT) and high-resolution magnetic resonance imaging (HR-MRI) to concomitantly visualize and quantify mineralization and vascularization at follow-up in a rat model. MATERIALS AND METHODS: Three adult female rats were randomly assigned as test subjects, with 1 rat serving as a control subject. For 20 weeks, the test rats received a weekly intravenous injection of 30 µg/kg zoledronic acid, and the control rat was administered a similar dose of normal saline. Bilateral extraction of the lower first and second molars was performed after 10 weeks. All rats were scanned once every 4 weeks with both micro-CT and HR-MRI. Micro-CT and HR-MRI images were registered and fused in the same 3-dimensional region to quantify blood flow velocity and trabecular bone thickness at T0 (baseline), T4 (4 weeks), T8 (8 weeks), T12 (12 weeks), T16 (16 weeks), and T20 (20 weeks). Histological assessment was the gold standard with which the findings were compared. RESULTS: The histomorphometric images at T20 aligned with the HR-MRI findings, with both test and control rats demonstrating reduced trabecular bone vasculature and blood vessel density. The micro-CT findings were also consistent with the histomorphometric changes, which revealed that the test rats had thicker trabecular bone and smaller marrow spaces than the control rat. CONCLUSION: The combination of micro-CT and HR-MRI may be considered a powerful non-invasive novel technique for the longitudinal quantification of localized mineralization and vascularization. ispartof: IMAGING SCIENCE IN DENTISTRY vol:50 issue:3 pages:199-208 ispartof: location:Korea (South) status: published

While several materials and techniques have been used to assess the quality of root canal fillings in micro-CT images, the lack of standardization in scanning protocols has produced conflicting results. Hence, the aim of this study was to determine a cutoff voxel size value for the assessment of root canal filling voids in micro-CT and nano-CT images. Twenty freshly extracted mandibular central incisors were used. Root canals were prepared with nickel titanium files to an ISO size 40/0.06 taper and then filled with a single cone (40/0.06 taper) and AH Plus sealer. The teeth were scanned with different voxel sizes with either micro-CT (5.2, 8.1, 11.2, and 16.73 μm) or nano-CT (1.5 and 5.0 μm) equipment. Images were reconstructed and analyzed with the NRecon and CTAn software. Void proportion and void volume were calculated for each tooth in the apical, middle, and coronal thirds of the root canal. Kruskal-Wallis and post hoc Mann–Whitney U tests were performed with a significance level of 5%. In micro-CT images, significantly different results were detected among the tested voxel sizes for void proportion and void volume, whereas no such differences were found in nano-CT images (p>0.05). Micro-CT images showed higher void numbers over the entire root length, with statistically significant differences between the voxel size of 16.73 μm and the other sizes (p<0.05). The values of the different nano-CT voxel sizes did not significantly differ from those of the micro-CT (5.2, 8.1, and 11.2 μm), except for the voxel size of 16.73 μm (p<0.05). All tested voxel sizes enabled the detection of root canal filling voids except for the voxel size of 16.73 μm. Bearing in mind the limitations of this study, it seems that a voxel size of 11.2 μm can be used as a reliable cutoff value for the assessment of root canal filling voids in micro-CT imaging.

Impulsivity is a core feature of attention-deficit hyperactivity disorder (ADHD). It has been conceptualized in a number of different ways. In the current article, we examine how the new concept of "waiting impulsivity", which refers to premature responding before a scheduled target appears, adds to our understanding of impulsivity in ADHD. Sixty children (8-12 years old; 30 ADHD; 30 typically developing controls) completed the 4-choice serial reaction time task, a measure of waiting impulsivity, alongside tasks measuring inhibitory control and temporal discounting and questionnaires measuring behavioral disorder symptoms, delay aversion, and various aspects of impulsivity. A multiple logistic regression model was used to explore the contribution of the primary task outcomes to predict group membership. Children with ADHD displayed more waiting impulsivity and less inhibitory control; they did not differ in temporal discounting. There was no correlation between waiting impulsivity and inhibitory control. Waiting impulsivity was correlated with parent-reported ratings of hyperactivity/impulsivity, inattention, oppositional defiant disorder (ODD), and conduct disorder (CD) and with self-reported delay aversion ratings. Only waiting impulsivity was a significant predictor of ADHD status. In conclusion, waiting impulsivity is distinct from inhibitory control deficits and predicts ADHD status independently of it. Future research needs to examine the relationship with delay aversion and ODD/CD more thoroughly.

Patient-specific mandibular reconstruction plate (PSMRP), as one of the patient-specific implants (PSIs), offers a host of benefits to mandibular reconstruction. Due to the limitation of fabricating screw hole threads in the PSMRP, 3D printed PSMRP is applied to the non-locking system directly in the mandibular reconstruction with bone graft regardless of the locking system. Since the conventional manual-bending reconstruction plate (CMBRP) provides better fixation in the locking system, it needs to be validated whether the locking PSMRP performs better than the non-locking PSMRP in the patient-specific mandibular reconstruction. Thereupon, the purpose of this study was to compare the biomechanical behavior between the locking and non-locking PSMRP. Finite element analysis (FEA) was used to conduct the biomechanical comparison between the locking PSMRP and non-locking PSMRP by simulating the momentary incisal clenching through static structural analysis. Mandible was reconstructed through the virtual surgical planning, and subsequently a 3D model of mandibular reconstruction assembly, including reconstructed mandible, PSMRP, and fixation screws, was generated and meshed for the following FEA simulations. In the form of equivalent von Mises stress, equivalent elastic strain, and total deformation, the locking PSMRP demonstrated its higher strengths of preferable safety, desirable flexibility, and anticipated stability compared with the non-locking PSMRP, indicated by much lower maximum stress, lower maximum strain and equivalent displacement. Locking PSMRP/screw system provides a better fixation effect to the patient-specific mandibular reconstruction than the non-locking one as a result of its productive fixation nature. FEA plays a paramount role in pre-validating the design of PSMRP through the biomechanical behavior evaluation in static structural analysis.

Background: Autologous plasma fractions, such as platelet-rich plasma (PRP) and platelet-poor plasma (PPP), contain growth factors that can enhance neural cell survival and are therefore likely to have the ability to promote nerve regeneration. The present study compared the effect of PRP and PPP application on myelinated nerve density and diameter in the peri-implant bone region. In addition, the effect of healing time on nerve regeneration was assessed. Materials and methods: Nine beagle dogs randomly received 54 dental implants in the bilateral mandible according to a split-mouth design. Each implant was randomly assigned to one of three implant protocols: delayed implant placement with delayed loading (DIP + DL) with local application of PRP, DIP + DL with local application of PPP and DIP + DL without any plasma additive. The animals were euthanized at 1, 3, and 6 months after loading (3 dogs per time point). Block biopsies were prepared for histomorphometry in the peri-implant bone within 500 mu m around the implants. Results: Myelinated nerve fibers were identified in the trabecular bone and in the osteons near the implants surface. The nerve fibers in the PRP group (median +/- IQR; 2.88 +/- 1.55 mu m) had a significantly (p < 0.05) greater diameter compared to the PPP (2.40 +/- 0.91 mu m) and control (2.11 +/- 1.16 mu m) group. The nerve diameter after 6 months healing (3.18 +/- 1.58 mu m) was significantly (p < 0.05) greater compared to 1 (2.08 +/- 0.89 mu m) and 3 (2.49 +/- 1.22 mu m) months. No significant difference was found for myelinated nerve density between groups and healing time. Conclusions: The present study showed that the healing time significantly influenced the diameter of the myelinated nerve fibers in peri-implant bone. PRP exerted a significant effect on the diameter of the myelinated nerve fibers as compared to PPP. Large-scale animal studies and longer follow-up periods are needed to confirm these findings and to verify whether platelet plasma can facilitate nerve regeneration process. This work was supported by a Sichuan Province Science and Technology Support Program (2016SZ0010). DS received fellowship support from the China Scholarship Council (201708210187). HY is a postdoctoral (11.N3.615N) and JVD is a predoctoral (11.ZU.117N) FWO-research fellow. Song, DD (reprint author), Katholieke Univ Leuven, OMFS IMPATH Res Grp, Dept Imaging & Pathol, Fac Med, Campus Sint Rafael,Kapucijnenvoer 33, BE-3000 Leuven, Belgium; Univ Hosp Leuven, Oral & Maxillofacial Surg, Campus Sint Rafael,Kapucijnenvoer 33, BE-3000 Leuven, Belgium. dandansong9015@gmail.com

e18503 Background: The prognosis for recurrent or metastatic Squamous Cell Carcinoma of Head and Neck (HNSCC) remains dismal and its treatment poses a challenge for oncologists. Agents against programmed cell death ligand 1 (PD-L1) have shown beneficial effects on overall survival (OS) for HNSCC. The aim of the present study was to compare differential effects of PD-L1 inhibitors on recurrent and metastatic HNSCC. Methods: In an indirect comparison of patients with recurrent HNSCC were matched to patients with metastatic HNSCC. All patients were treated with PD-L1 inhibitors at the general medical oncology department of UZ Leuven. Kaplan-Meier methods and Cox regression models were used to calculate the overall survival. Results: From December 2013 to July 2019, 68 patients with metastatic and 59 with recurrent HNSCC were enrolled and evaluable. A significant difference in OS was found between recurrent and metastatic groups (p < 0.02). The mean OS was 7.6 months (95% CI: 2.4-11.3 months) for the recurrent group, while in the metastatic group the mean OS was 13.7 months (95% CI: 5.7-16 months). Conclusions: As a second-line therapy, PD-L1 inhibitors were associated with longer overall survival in metastatic compared to recurrent HNSCC.

Contains fulltext : 194110.pdf (Publisher’s version ) (Open Access) Background: Experimental research supports delay aversion as a motivational feature of attention deficit/hyperactivity disorder (ADHD). To investigate the neurobiology of delay aversion in ADHD, this study examined whether adolescents with ADHD display an unusually strong activation in affective brain regions in response to cues predicting forthcoming delay and whether these effects are (a) delay‐dose dependent and (b) statistically mediate the association between ADHD and self‐reported delay aversion. Methods: Twenty‐nine right‐handed male adolescents with combined type ADHD and 32 typically developing controls (ages 10–18 years) performed a reaction time task in an MRI scanner. Pretarget cues indicated delay‐related response consequences. One indicated that delay would follow the response irrespective of response speed (CERTAIN DELAY), a second that delay would only follow if the response was too slow (CONDITIONAL DELAY), and a third that no delay would follow the response whatever its speed (NO DELAY). Delay levels were 2, 6, or 14 s. Participants also rated their own delay aversion in everyday life. Results: Individuals with ADHD rated themselves as more delay averse than controls. Significantly greater activation to CERTAIN DELAY cues relative to NO DELAY cues was found in participants with ADHD compared to controls (bilaterally) in amygdala, anterior insula, temporal pole, dorsolateral prefrontal cortex (DLPFC), and ventromedial prefrontal cortex. Amygdala and DLPFC activation strength were strongly and delay‐dose dependently correlated with delay aversion ratings, and statistically mediated the relationship between ADHD status and delay aversion. Conclusions: When presented with cues predicting impending delay, adolescents with ADHD, relative to controls, displayed a delay‐related increase in activation in amygdala and DLPFC, regions known to be implicated in the processing of aversive events. Future studies should examine the specificity of these effects to delay aversion compared to aversive events in general. 12 p.

Despite great interest in bisphosphonate-induced osteonecrosis of the jaw (ONJ), the underlying pathology remains a matter of debate. In most reports, the etiology of ONJ seems to be ascribed to bisphosphonate-related over suppression of bone remodeling. While suppression of bone remodeling is indeed the prime action mechanism of bisphosphonates, the destructive ONJ effects at the level of the jaw bone are ignored or minimalized when prescribing these drugs. The present study therefore investigated the long-term effects of oncological Zoledronic Acid (ZA) doses on the three factors which may comprise jaw bone:(1) bone quantity, (2) bone structure and (3) bone mineral density (BMD). Twentyfour, healthy, Wistar rats were randomly divided in an experimental group (n = 12) receiving 0.6 mg/kg body weight/month ZA and a control group (n = 12) receiving an equal volume of saline for 5 consecutive months. The ZA doses were equivalent to the doses given to oncologic patients. After animal sacrifice, their mandibles were ex vivo scanned using 1174 micro-CT (Bruker) and the obtained scans were spatially aligned. One mean volume of interest containing only trabecular bone below the apex of the molars was selected, in which 3D quantitative morphometry and BMD were calculated using CT-Analyser (Bruker). Structural-related parameters showed significantly (P < 0.001) increased osteoslerotic characteristics of the alveolar bone (↑ Tb.Pf; ↓ Tb.Sp; ↓Tb.N; ↓ SMI; ↓ Conn.Dn) in ZA-treated rats as compared to the controls. These findings were confirmed by a significantly (P < 0.001) increased bone quantity (↑ BV/TV; ↑ Tb.Th; ↓ BS/TV; ↓ Po[tot]). Finally, the alveolar bone displayed a significantly (P < 0.001) higher BMD after prolonged ZA therapy. These results are strongly supportive for bisphosphonateinduced oversuppression of alveolar bone remodeling. The bone becomes more sclerotic leading to less vascularization and an ONJ prone jaw

Aim The objective of this proof-of-concept study was to investigate the effects of a new guided bone regeneration technique with a tissue engineering approach. Materials and methods This single cohort observational study evaluated the outcome of the leucocyte- and platelet-rich fibrin (L-PRF) Block for horizontal bone augmentation in the maxilla. The L-PRF Block is prepared by mixing a particulated biomaterial with chopped L-PRF membranes at a 50:50 ratio and adding liquid fibrinogen to glue all together. Horizontal augmentation was assessed linearly and volumetrically immediately after surgery and 5-8 months later by matching consecutive cone beam computed tomography (CBCTs). Results Ten patients (mean age of 50.7 years [±17.2]) representing 15 sites with horizontal alveolar deficiencies were included. Superimposition of pre-operative and posthealing CBCT scans showed an average linear horizontal bone gain of 4.6 mm (±2.3), 5.3 mm (±1.2) and 4.4 mm (±2.3), measured at 2, 6 and 10 mm from the alveolar crest, respectively. The volumetric gain was 1.05 cm3 (±0.7) on average. The resorption rate after 5-8 months was 15.6% (±6.7) on average. Conclusions L-PRF Block may be a suitable technique to augment deficient alveolar ridges.

Background Little attention has been paid to the effect of implant restorations on speech. Purpose The aim of this study was threefold: (1) to find out if speech problems occur after inserting a fixed provisional restoration in the edentulous maxilla; (2) to explore speech adaptation in case articulation problems arise after rehabilitation; and (3) to describe the effect of changing the shape of the restoration on improving speech. Materials and Methods Ten patients with an edentulous maxilla were treated with fixed rehabilitation on implants. Speech evaluation was performed at four occasions: before implant surgery, immediately after restoration, and 3 weeks later before and after managing the speech problem by changing the shape of the restoration if speech problems occurred. Comparative three-dimensional-analysis of casts of the restoration before and after changing the shape of the restoration was carried out. Results The majority of patients (n = 7) experienced speech problems immediately after rehabilitation. Three weeks later, none of the seven patients with deteriorated speech returned to baseline speech. Then, volumetric reduction of the palatal aspects of the (pre)molars was performed, which allowed speech to return to baseline levels in five out of seven patients. In the two remaining patients, the intervention resulted in an improvement of speech without reaching their baseline levels. Three-dimensional-analysis showed that reducing the palatal volume of the premolars was effective in correcting speech. Conclusions Speech problems may frequently occur after fixed rehabilitation of the completely edentulous maxilla. A novel speech management concept, consisting of reducing the palatal volume of the (pre)molars, is introduced, demonstrating to solve speech problems in most cases.