Mandibular Arch Research Articles

Cxcl12a plays an essential role in pharyngeal cartilage development.

Background: Neural crest cells constitute a distinct set of multipotent cells that undergo migration along predefined pathways, culmination in the differentiation into a plethora of cell types, including components of the pharyngeal cartilage. The neurocranium is composite structure derived from both cranial neural crest and mesoderm cells, whereas the pharyngeal skeletal elements-including the mandibular and branchial arches-are exclusively formed by craniofacial neural crest cells. Previous studies have elucidated the critical involvement of the chemokine signaling axis Cxcl12b/Cxcr4a in craniofacial development in zebrafish (Danio rerio). Nonetheless, the function contribution of Cxcl12a and Cxcr4b-the homologous counterparts of Cxcl12b and Cxcr4a-remain largely unexplored. Methods: In the present study, mutant lines for cxcl12a and cxcr4b were generated employing CRISPR/Cas9 system. Temporal and spatial expression patterns of specific genes were assessed using in situ hybridization and dual-color fluorescence in situ hybridization techniques. High-resolution confocal microscopy was utilized for in vivo imaging to detect the pharyngeal arch or pouch patterning. Additionally, cartilage formation within the craniofacial region was analyzed via Alcian blue staining, and the proliferation and apoptosis rates of craniofacial neural crest cells were quantified through BrdU incorporation and TUNEL staining. Results: Our data reveals that the deletion of the chemokine gene cxcl12a results in a marked diminution of pharyngeal cartilage elements, attributable to compromised proliferation of post-migratory craniofacial neural crest cells. Subsequent experiments confirmed that Cxcl12a and Cxcl12b exhibit a synergistic influence on pharyngeal arch and pouch formation. Conclusion: Collectively, the present investigation furnishes compelling empirical evidence supporting the indispensable role of Cxcl2a in craniofacial cartilage morphogenesis, albeit cxcr4b mutants exert a minimal impact on this biological process. We delineate that Cxcl12a is essential for chondrogenesis in zebrafish, primarily by promoting the proliferation of craniofacial neural crest cells. Furthermore, we proposed a conceptual framework wherein Cxcl12a and Cxcl12b function synergistically in orchestrating both the pharyngeal arch and pouch morphogenesis.

Systematic Management of Severe Anterior Tooth Surface Loss using Provisional Onlay and Permanent Overlay Removable Prostheses: A Case Report

Background: Management of severe tooth surface loss presents a growing difficulty that is encountered increasingly in everyday practice. Loss of posterior support has been identified as the causative factor in severe anterior tooth surface loss, leading to a reduction in the occlusal vertical dimension and complex tooth wear, which can affect the quality of life. Objective: The purpose of this report is to show the systematic approach utilized in the management of severe anterior tooth surface loss in a partially edentulous old patient. Case Report: This report describes the management of a 59-year-old gentleman with a complaint of short anterior teeth as well as inefficient function. Clinical examination revealed short anterior teeth and multiple missing teeth posteriorly, which resulted in the loss of posterior tooth support. The management of this case involved reorganizing the occlusion to create the restorative space, which was achieved by a combination of fixed and removable restorations. The short- and medium-term management consisted of an occlusal splint, endodontic treatment, composite build-ups, provisional onlay acrylic dentures, and metal copings. Single crowns and removable cobalt chrome partial dentures were the definitive treatment for the maxillary arch, while a modified overlay cobalt chrome partial denture with cast facings and custom-made porcelain teeth was fabricated for the mandibular arch. Results: The patient was able to function well with the provisional onlay denture, and at the same time, the increased vertical dimension and the patient’s tolerance and compliance to partial denture treatment were evaluated. The permeant overlay partial denture restored the patient’s aesthetics and function, with minor adjustments needed. At the 2-year review appointment, the patient denied experiencing any muscular or temporomandibular joint soreness or dental complaints except for minor sensitivity. The patient was compliant and satisfied with the overall performance of the dentures. Conclusion: A systematic approach to the management of a patient with a complex presentation can lead to a predictable and favourable prognosis. Onlay and overlay removable partial dentures are regarded as treatment alternatives that are non-invasive, reversible, and conservative.

Novel reconstruction method of angle-limited backprojection (ALBP) for low-dose dental panoramic X-ray imaging

Panoramic radiography is a popular two-dimensional X-ray imaging modality in dentistry. It produces a single image of the overall facial view, including the maxillary and mandibular arches and supporting structures. Panoramic images are typically reconstructed using the shift-and-add (SAA) algorithm, in which only structures within a certain image layer are in focus, and others are out of focus on the panoramic image. As the clinical use of panoramic radiography has grown rapidly, radiologists are continuously seeking ways to reduce the radiation dose to patients. This study proposes a novel panoramic reconstruction method called the angle-limited backprojection (ALBP) algorithm for low-dose panoramic X-ray imaging. In ALBP, X-rays that meet the angular criterion established in this study are selected from the measured panoramic projection data and then backprojected onto the spherical voxels placed along the dental arch, as in a typical computed tomography reconstruction. The angular criterion selects X-rays that pass through a given spherical voxel and simultaneously have directional vectors within a prespecified angular range concerning the directional vector at the corresponding source position. To validate the efficacy of the proposed reconstruction method, we conducted a numerical simulation and experiment and investigated the image characteristics. Panoramic images were reconstructed using the SAA and ALBP algorithms with full and half (i.e., half radiation dose) panoramic projections, and their image quality was quantitatively evaluated using the intensity profile and universal quality index (UQI). The image quality of the ALBP with half projections was similar to that of the SAA with full projections, indicating the efficacy of the proposed method. Accordingly, our results demonstrated the potential for radiation dose reduction in panoramic X-ray imaging.

A Case History of Gross and Radiological Observations of Agnathia: Otocephaly in a Mehraban Ewe-lamb

Agnathia is one of the first pharyngeal arch deformities referred to as mandibular abnormality. This case report aimed to describe an unusual form of agnathia-otocephaly in a Mehraban ewe-lamb accompanied by other malformations. The scrutiny of the lamb’s face indicated a chain of abnormalities in the head region. Lack of mandible, lips, rima oris, oral cavity, tongue, and teeth were recognized. Eyes and ear lobes were normal, but the base of the pinnae met each other ventral to the atlantooccipital joint and formed a single external acoustic meatus there. The nostrils were normally formed, but the philtrum was not formed due to the lack of lips, especially the upper lip. The hyoid apparatus was normally developed. The laryngopharynx had no connection with the nasopharynx and dead end. Also, the nasal cavities ended blindly because of rinopharyngeal aplasia and no choanal foramen. So, the abnormal pharyngeal region caused a non-functional respiratory system followed by death.

Erosive Tooth Wear in Subjects with Normal Occlusion: A Pioneering Longitudinal Study up to the Age of 60.

The aim of this study was to assess the erosive tooth wear (ETW) at early and mature adulthood in subjects with natural normal occlusion. The sample consisted of 23 untreated subjects with normal occlusion. Dental models were taken longitudinally from the same subjects at 13 (T0), 17 (T1) and 60.9 years of age (T2) at a university. Evaluation of ETW was performed using a modified Basic Erosive Wear Examination (BEWE) index. Interphase changes were evaluated using Friedman and Dunn's test. Ordinal logistic regression was used to assess the influence of sex, dental arch, tooth and dental surfaces on the erosive tooth wear. Linear regression was used to evaluate whether the ETW degree at T1 could discriminate the degree of ETW at T2. The significance level adopted was 5%. ETW showed a significant increase with aging. The median ETW index at T0, T1 and T2 was 2, 4 and 7, respectively. ETW was greater in males in the incisors and canines and on the incisal/occlusal and lingual tooth surfaces. No significant differences were found between the maxillary and mandibular arches. Subjects with severe ETW at mature adulthood had greater tooth wear at age 17. In conclusion, ETW significantly increased during aging in subjects with normal occlusion. The greater the degree of tooth wear at early adulthood, the greater the tooth wear at mature adulthood. Preventive care should be recommended during early adulthood in patients demonstrating erosive tooth wear in order to avoid worsening with aging.

Correlation of Dose Volume Parameters with Dysphagia and Pharyngeal Constrictor Muscle Thickness in Dysphagia Optimized IMRT

Reduced radiation dose to the pharyngeal constrictor muscles (PCM) using dysphagia optimized intensity-modulated RT (DO-IMRT) is associated with improved swallowing outcomes in oropharyngeal cancers (OPCs). Purpose was to evaluate the relationship between dose of radiation delivered and acute dysphagia in patients with OPC treated with IMRT, after delineation of PCM. Twenty-five patients with newly diagnosed OPC who underwent definitive IMRT with concurrent cisplatin were included in the study. PCM mean dose < 50 Gy was used as the dose constraint. Target volume was divided into high, intermediate and low risk areas receiving doses in the range of 60-66 Gy, 54-58 Gy, 51-56 Gy in 30-33 fractions over 6-6.5 weeks, respectively. PCM dose-volume parameters were collected and logistic regression was used to analyze these data relative to percent weight loss during RT and duration of feeding tube use. Thickness of constrictor muscle in pre-treatment and 3 months post-therapy CT scan were assessed. Weekly assessment of dysphagia was based on RTOG toxicity gradings. Aim of the study was to evaluate the correlation between dysphagia grades with dose-volume parameters and PCM thickness. Median age was 55.0 years (mean 54.3) with 24 males and stage II:III-16:9 patients. Dmean to PCM was 49.86 Gy (range 48.22 -57.63) with median Dmax of 70.24 Gy. For patients with dysphagia (grade ≥1), V50 ranged from 48.2-57.23%, while in those with no dysphagia, it ranged from 47.92-52.18 % (Mean 51.36%). Nine patients needed feeding tube after RT end. Median feeding tube duration was 64 days. The correlation between Dmean ≥ 50 Gy and dysphagia at 1st, 2nd, 3rd and 6th month was found statistically significant (p < 0.01). Table 1 shows the Pearson correlation and P-value of the dosimetric parameters with dysphagia. The correlation of V50 was found statistically significant with grade of dysphagia at 3rd and 6th month post-treatment (p<0.001). The mean thickness range and median thickness of constrictors before and 3 months after treatment were 1.8-3.2 mm, 2.4 mm, and 2.8-6.2 mm,4.1 mm, respectively. The increase in thickness of constrictor muscle correlated significantly (p<0.05) with dysphagia grades and also with V50, V60 and Dmean (p<0.001) but no statistical significance was seen with Dmax (p = 0.232). With a median follow-up of 18 months (range 7-24), 1-year actuarial local control was 92%. DO-IMRT may prove beneficial in the OPC by preventing dysphagia and aspiration post therapy and hence improving the quality of life of patients. Dmean ≥ 50Gy, V50 > 51.4% and V60 > 35.5% are the parameters correlating significantly with dysphagia (p<0.001) and change in mean thickness of PCM (p<0.001).

Dosimetric Parameters Correlate with Taste Alterations in Head and Neck Radiotherapy

Dysgeusia is an acute and chronic side effect of head and neck chemoradiation, with persistent taste dysfunction 1-2 years post radiotherapy occurring in 23-50% of patients. Several head and neck clinical trials set oral cavity mean doses between 30 to 40 Gy, however, there are no set guidelines accurately defining the composite structure and anatomic boundaries for the oral cavity or separating the tongue into specific quadrants. In this single institution cross sectional study, we sought to determine the effects of radiation doses to specific regions of the oral cavity and tongue on patient-reported long term dysgeusia. We hypothesize that radiation Dose to specific structures in the oral cavity will correlate with long-term dysgeusia in patients who have received head and neck radiotherapy. Patients with primary head and neck cancer receiving definitive intensity modulated radiation therapy (RT) completed quality of life assessments that included patient-reported gustatory function, 1 year post RT. Dosimetric data from RT plans were collected for specific regions and organs at risk within the oral cavity. These structures included the anterior, posterior, superior and inferior tongue (OT), pharyngeal constrictors (as a surrogate for the corda-tympani) and the oral cavity. A forward binary logistic regression model was performed using these data points with scoring from the QLQ-H&N43 questionnaire subsection on taste (Q45) to determine the most predictive values for dysgeusia and the OR for moderate/severe alterations in taste. A total of 78 patients were included in this study, of these patients, 63 had dosimetric data for the pharyngeal constrictors. The Oral Cavity Volume percentage receiving 50Gy (OC V50) and Pharyngeal Constrictors Volume percentage receiving 55Gy (PC V55) were the most predictive constraints for dysgeusia. (0.042, p = 0.011 and 0.041, p = 0.033). Holding all other variables constant in a forward binary logistic regression including 78 patients, the odds of having moderate to severe taste alterations increased by 56% (OR 1.045, 95% CI 1.012-1.079) for a 1% increase in OCV50. When analyzing the 68 patients with available pharyngeal constrictors data, taste alteration increased 20% for every 1% increase in PCV55 (OR 1.042, 95% CI 1.003-1.082). There was no correlation with taste alterations in any of the dose parameters tested (Dmax, mean and V50 up to V70) for superior, inferior, anterior or posterior regions of the tongue. Dosimetric parameters for the oral cavity (OC V50) and pharyngeal constrictors (PC V55) were positively correlated with taste alterations, however, no other specific regions within the oral tongue predicted taste disfunction. Normal tissue complication probability modeling curves to identify OC V50 and PC V55 constraints for dysgeusia are needed.

EVALUATION OF TRAUMATIC ULCERATIONS FREQUENCY AND SITE IN POST-INSERTION ADJUSTMENT RECALL VISITS IN COMPLETE DENTURE PATIENTS VISITING A DENTAL COLLEGE IN CHITWAN

Background: During the initial days after complete denture insertion, patients can face various difficulties like traumatic ulcerations, loss of retention, unstable denture, difficulty in mastication and speech etc. The aim of the study was to assess the site and number of traumatic ulcerations in maxillary and mandibular denture bearing area in post-insertion adjustment recall visits and also to find out the total number of adjustments recall visits required until the patients become comfortable with the denture. Methods: A cross-sectional study was conducted among 75 complete denture patients to look for the number and site of traumatic ulcerations and the number of post-insertion recall visits required until they became symptom free. Descriptive (frequency and percentage) statistical analysis was done using SPSS Statistical Software Package (version 21.0). Results: In the mandibular arch 49.33% (N=34) and in the maxillary arch 12.5% (N=9) patients required adjustment visits for traumatic ulcerations. In the first recall visit after 24 hrs, 34 patients showed traumatic ulcerations on mandibular arch while only 6 patients experienced traumatic ulcerations on the maxillary arch. Conclusions: The patients required more post insertion adjustments for traumatic ulcerations in the mandibular arch in comparison to maxillary arch. Traumatic ulcerations was most frequently found in distobuccal sulcus area in the maxillary arch and labial sulcus in the mandibular arch.

Partial Tongue Sparing without Marginal Failures: The Dosimetric Advantages for Oral Tongue Squamous Cell Carcinoma

Due to a lack of internal barriers, many radiation oncologists believe whole tongue (WT) irradiation is warranted in the adjuvant setting for oral tongue cancer. Our institutional practice is to include the resection bed and flap with a 5-10 mm margin, attempting to spare unaffected oral tongue. We hypothesize that partial tongue (PT) irradiation, when feasible, results in decreased dose to surrounding normal structures without an increased risk of local recurrence (LR). Patients with a new diagnosis of squamous cell carcinoma of the oral tongue treated with adjuvant IMRT between 2010 and 2021 were collected from an IRB approved database. PT was defined as <80% of residual tongue in the clinical target volume (CTV). Recurrence was deemed local if in the tongue or floor of mouth, and in field if within the CTV or marginal if outside of CTV. Mean dose to mandible, pharyngeal constrictors, and oral cavity were evaluated. Comparisons between groups were made using parametric one-way ANOVA. Multivariable linear regression was used to predict mean radiation dose. Local control and overall survival were estimated using Kaplan-Meier. A total of 130 patients are included with median follow up 34.1 months (IQR 13.5-64.6). Radiation dose was 48-72 Gy in 24-36 fractions, most commonly 60-66 Gy in 30-33 fractions (84.6%). All were treated to oral cavity, and neck irradiation included bilateral 96 (72%), unilateral 31 (24%), and none 3 (4%). PT sparing was feasible in 91 (70%) and 39 (30%) required WT. Primary tumor stage in PT included 20 pT1, 50 pT2, 17 pT3, and 4 pT4, and WT included 3 pT1, 8 pT2, 15 pT3, and 13 pT4. 3-year local control for PT and WT was 96% and 87%, respectively. LR occurred in 14 patients overall (10.8%), 6.6% (6) of patients treated with PT and 20.5% (8) treated with WT (p = 0.072). Of the LR for PT, stage was 2 pT1, 3 pT2, and 1 pT3, and all occurred within the radiation field. Of the LR for WT, stage was 1 each of pT1 and pT2, 2 pT3, and 4 pT4. Overall survival was 57%, regional and distant recurrence was each 17.7%. Dosimetric analysis for PT vs WT is described in Table 1, demonstrating lower mean dose when the primary tumor CTV is limited to PT. Unilateral neck irradiation also resulted in a lower mandible [-8.5 Gy (-11.2 - -5.8)], pharyngeal constrictor [-14.3 Gy (-18.1 - -10.5)], and oral cavity [-9.0 Gy (-13.0 - -5.0)] dose (all p<0.001). Limiting the primary tumor CTV to PT for adjuvant radiotherapy resulted in significant sparing of the mandible and pharyngeal constrictors, and a routinely lower oral cavity mean dose of ≥3.5 Gy. There was a low risk of LR when implementing PT, and all LR occurred in field. Given the increased sparing of normal structures, and low risk of LR outside of PT radiation field, sparing a portion of unaffected oral tongue should be considered.

Comparison of tissue displacement in edentulous arches among three-dimensional files obtained through different impression-making methods: A retrospective study.

To retrospectively compare and analyze differences in tissue displacement of edentulous arches among three-dimensional (3D) files obtained using various impression-making techniques. Fourteen patients who underwent prosthodontic treatment for edentulous arches at Yonsei University Dental Hospital between June 2020 and April 2023 were included in the study. Three types of 3D files were used for the evaluation of each arch: a 3D scan file of a definitive cast (Group DEF), a preliminary cast (Group PRE), and an intraoral scan file (Group IOS). The files were superimposed on a reference 3D scan file of the definitive cast group through best-fit matching using metrology software. Seventeen measurement points (MP1-4, RC1-6, TB1-2, and PPS1-5 for the maxilla and RP1-2, RC1-7, BS1-4, and LS1-4 for the mandible) were selected for both the maxillary (n = 13) and mandibular arches (n = 6). The deviation considering the direction (DD) between the three groups and the absolute deviation (AD) between the three groups were recorded. Kruskal-Wallis and post-hoc Mann-Whitney tests were used for statistical analyses (α = 0.05 and α = 0.0167, respectively). Concerning the DD values, at the RC4 point of the maxillary arch, Group PRE exhibited significantly higher values than Groups IOS (p = 0.006) and DEF (p < 0.001), and at the RC5 point of the maxillary arch, Group IOS exhibited significantly lower values than Groups PRE (p = 0.016) and DEF (p < 0.001). Group IOS showed significantly lower DD values in the mandibular arch than Group DEF at the RP2 and RC3 points (p < 0.167). The AD values in Groups PRE and IOS significantly differed from those in Group DEF (all p < 0.001) at all measurement points but did not exhibit significant differences between each other (p > 0.05). Different impression-making methods yielded different amounts of tissue displacement. The tendency of 3D files regarding tissue displacement varied at certain residual ridge crest areas and retromolar pad areas. The absolute amount of tissue displacement observed in the intraoral scan data was comparable to that observed in the preliminary casts.

Predicting Acute Radio-Induced Toxicity for Head and Neck Cancer Patients: Combining Dosimetry with Biomarker Data, Disclosing a Synergistic Effect

We aimed to establish the added value of combining dosimetry with a binary blood assay for radiosensitivity based on quantification of pATM protein (RADIODTECT©) to predict acute radiotherapy (RT) induced mucositis (MUC) and dysphagia (DYS) in head & neck cancer patients (pts). We enrolled 101 pts prospectively scored for acute toxicity with CTCAE. We considered four endpoints: grade≥2 (G2+) and grade≥3 (G3+) MUC, G2+, and G3+ DYS. We dichotomized the pATM concentration to define radiosensitive (RS) vs. radioresistant (RR) pts using previously described cutoffs for G2+ (57.8 ng/mL) and G3+ toxicity (46 ng/mL). We did RADIODTECT© and toxicity scoring blindly. We considered two already published NTCP models, including (i) the Equivalent Uniform Dose to the oral cavity (n = 0.05, EUD_OC, Odds Ratio [OR] = 1.02) and the mean dose to the parotid glands (Dmean_PG, OR = 1.06) for MUC and (ii) EUD_OC (OR = 1.04), the glottic larynx EUD (n = 0.35, EUD_GL, OR = 1.02) and the volume of pharyngeal constrictor muscles receiving>50Gy (V50Gy_CM, OR = 1.02) for DYS. To account for the association of toxicity with the dose distribution in multiple organs at risk (OARs), we derived a "Weighted Dose Score" (WDS) as a linear combination of the dose factors, using their β-coefficients (= lnOR) as weights. WDS for MUC (WDS_OM) = 0.06*Dmean_PG + 0.02*EUD_OC WDS for DYS (WDS_DYS) = 0.02*V50Gy_CM + 0.02*EUD_GL + 0.04*EUD_OC We used WDS as a comprehensive dose feature to fit a dose response and allowed WDS50 (i.e., the WDS associated with 50% toxicity probability) to be different for RR (WDS50_RR) and RS pts (WDS50_RS). The dose-modifying factor (DMF) is the ratio of WDS50_RS/WDS50_RR. It measures the horizontal shift of the dose-response curve when comparing RS vs. RR pts. We scored G2+ and G3+ MUC in 80 and 41 pts; G2+ and G3+ DYS in 73 and 35 pts. The average concentration of pATM was 57.4ng/mL (sd 22.3ng/mL): 53/101 pts were classified as RS for G2+ toxicity and 35/101 as RS for G3+. On the whole cohort, the RADIODTECT© did not significantly associate with the risk of toxicity. However, we found two different dose-response curves at low WDS. There, the intrinsic biological sensitivity significantly affects the toxicity probability: ORs for RADIODTECT© are 2.6/2.4 for G2+/G3+ DYS, 6.4/2.9 for G2+/G3+ MUC. Furthermore, the difference in the incidence of side effects in RR vs. RS pts decreases as the WDS increases, reaching a region where the doses of OARs play a significant role. When combined with WDS, the RADIODTECT© effectively predicted RS pts, with DMF ranging from 0.77 for G3+ DYS to 0.40 for G2+ MUC. These findings support the hypothesis that dose and biomarkers act synergistically; biologically based radiosensitivity plays a significant role when OARs are exposed at lower doses, while high doses of OARs determine toxicity irrespective of the underlying single pt biological characterization.

The rehabilitation nurse's intervention in elderly people with dysphagia: systematic literature review

Context: Dysphagia in aging is associated with malnutrition and cognitive changes resulting from the natural decline of the body's homeostasis at the end of life. It is a permanent challenge for the rehabilitation nurse (RN) to ensure a safe nutrition of the elderly person by re-educating swallowing. Objective: To identify the current scientific evidence on the effectiveness of swallowing rehabilitation interventions in older people with dysphagia. Methodology: Systematic Literature Review (SLR) conducted according to the methodology proposed by the Joanna Briggs Institute, based on studies published between 2017 and 2022, in the databases: CINAHL Complete, MEDLINE Complete, Nursing &amp; Allied Health Collection: Comprehensive Edition and Cochrane Central Register of Controlled Trials and PubMed. Critical appraisal, data extraction and synthesis were performed by two independent reviewers. Results: Initially 647 articles were identified, however only 7 were included in this Review as they met the defined criteria. We found very disparate oropharyngeal rehabilitation plans, particularly regarding the type of exercises/techniques and the use of devices. As for the devices, we tested the Gentle Stim® for transcutaneous electrical neurostimulation (TENS); the IQoro® to stimulate sensory input and strengthen facial, oral, and pharyngeal muscles; the Tongue Pressure Strengthening (TPS) for tongue muscle exercise with resistance training. Conclusion: The elderly person can improve swallowing ability if subjected to a personalized oropharyngeal rehabilitation plan, minimizing the risk of complications. Further research by RN is recommended.

What is missing from the sturgeon jaw: Developmental morphology of the upper jaw in Acipenser.

Sturgeons belong to the family Acipenseridae, the most species-rich extant family of Acipenseriformes, a basal actinopterygian group of key importance in assessing the early radiations of the actinopterygians. At the same time, acipenseriforms display unique specializations in the morphology of the snout and jaws which make them a valuable model for studying evolutionary novelties. However, despite a long history of research, the homologies of the snout and the mandibular arch of acipenseriforms remain uncertain preventing further studies on the evolutionary origin of their unique snout and jaw structure, and in particular, of the upper jaw symphysis, the key apomorphy of the group and the preoral snout. In the present study, a detailed description of the upper jaw morphology and development in sturgeons is provided in order to address its composition in terms of the common actinopterygian archetype. Based on the obtained results, the upper jaw of acipenseriforms is assumed to have lost the autopalatine portion, which most likely is represented by the separate cartilages supporting the tentacles. Also, the conventional interpretation of the sturgeon's maxilla as dermopalatine is rejected on the grounds of this bone structure and development. Paedomorphosis is proposed to be the most likely mechanism explaining the evolutionary origin of the upper jaw symphysis and supposed modifications of the snout in sturgeons.

Is wear time of Hawley retainers measured with microsensors related to mandibular arch stability?

The aim of this study was to show apossible correlation between the mean wear time of Hawley retainers and long-term mandibular arch stability as assessed via wear time analysis with microsensors. This longitudinal retrospective study comprised 47subjects (mean age 16.30 ± 1.06years) having been treated with anonextraction protocol and presenting moderate crowding at pretreatment. For retention, all patients were instructed to use amandibular Hawley retainer for 12months, and wear time was documented every 3months during aposttreatment period of 6months using TheraMon software. These individuals were divided into two groups. Those who adhered to awear time equal to or more than 12 h/day (group1A; N = 17) and those who complied for less than 12 h/day (group2A; N = 30) were compared with respect to changes of the mandibular arch during the first 6months of retention. Furthermore, asubgroup of 28patients who completed a12-month follow-up period were again divided into two groups: the individuals in group1B (N = 12) adhered to awear time equal to or more than 8 h/day, while those in group2B (N = 16) complied for less than 8 h/day. Little's Irregularity Index, intercanine and intermolar widths, arch length, overjet, and overbite were measured on mandibular models taken at pretreatment (T0) and posttreatment (T1), as well as 6months (T2) and 12months (T3) after debonding. Pearson correlation test, independent samples t‑test, and Mann-WhitneyU test were used for statistical evaluation. From T1to T2, group1A and group2A showed asignificant relapse in intermolar width with adifference in the median value of 0.38 mm (p = 0.019). At the complete 12-month follow-up, the increase in Little's irregularity score was significantly greater in group2B (2.54 ± 1.29 mm) than in group1B (1.32 ± 1.03 mm; p = 0.012). The established wear time measurements showed significant negative correlations with the Little's irregularity score and overjet changes between T1 and T3 (p < 0.05). The results emphasized that the use of aretainer should not fall below alevel of at least 8 h/day.

In-vitro comparison of two different toothbrush bristles about peri-implant sulcus penetration.

The aim of this preclinical study was to compare the ability of tapered and cylindrical bristles to penetrate the peri-implant sulcus. A full mandibular dental arch was reproduced in plaster cast. In site #3.6 a hollow glass cylinder was positioned simulating a 4 mm diameter implant and the gingival component was recreated by using dedicated silicone. A Bass brushing technique was performed from the vestibular side in humid environment. During it, the penetration of the bristles between the gum and the implant was recorded by mean of an optic fibre fixed inside the cylinder. The protocol included 5 toothbrushes per group and 10 tests per toothbrush, for a total of 50 assessments for each of the two groups. A scale of 5 grades for bristle penetration was defined: grade 0 (× < 2 mm), grade 1 (2 ≤ × < 3 mm), grade 2 (3 ≤ × < 4 mm), grade 3 (4 ≤ × < 5 mm) and grade 4 (5 ≤ × < 8 mm). From the video recordings the highest value of penetration was identified for each test. The tapered bristles showed an 8 times greater penetration capacity (p = 0.001) in respect to the cylindrical bristles (multilevel analysis). The percentage of tests reaching depths ≥3 mm was 86% for tapered group and 28% for the cylindrical group. This preclinical study shows a clear and superior penetration capacity of the tapered bristles in respect to traditional cylindrical ones. For tapered bristles, a potentially greater hygienic efficacy around dental implants is suggested.

Three-dimensional Anatomy of the Velopharyngeal Muscles in the Cleft Palate.

We have used micro-computed tomography (CT) to elucidate the relationship between the muscle fibers in specimens with cleft palate. These findings could be useful for muscle reconstruction in cleft palate repair and to better understand cleft palate speech. Cadaveric anatomical study. This study included three specimens with cleft palate. The specimens were stained with phosphomolybdic acid and scanned by Micro-CT. The anatomy of the muscles. Using 2D projection images and 3D reconstruction models, subtle anatomical structures could be observed in the muscles. The attachment of the levator veli palatini (LVP) was not at the posterior edge of the hard palate or palatine aponeurosis (PA), but at the anterior 21.71-44.2% of the cleft edge. The palatopharyngeal (PP) was composed of two bundles: inferior and superior heads, which clasped the LVP. The uvularis was unevenly distributed, and located on both sides of the cleft edge, originating at the edge. The palatoglossus, superior constrictor of pharynx and anatomical structure around the pterygoid hamulus, were normal. The PA, PP and LVP were attached to the cleft edge from front to back, in that order. The position of the uvularis was not fixed. With the help of Micro-CT technology, detailed anatomical features and the relationship between muscles could be visualized. In the specimen with cleft palate, muscles in the soft palate were associated with the pharyngeal muscles, which formed the 3D "velopharyngeal muscles complex." These findings provide anatomical evidence for muscle reconstruction in cleft palate repair.

Machine learning based orthodontic treatment planning for mixed dentition borderline cases suffering from moderate to severe crowding: An experimental research study.

Pedodontists and general practitioners may need support in planning the early orthodontic treatment of patients with mixed dentition, especially in borderline cases. The use of machine learning algorithms is required to be able to consistently make treatment decisions for such cases. This study aimed to use machine learning algorithms to facilitate the process of deciding whether to choose serial extraction or expansion of maxillary and mandibular dental arches for early treatment of borderline patients suffering from moderate to severe crowding. The dataset of 116 patients who were previously treated by senior orthodontists and divided into two groups according to their treatment modalities were examined. Machine Learning algorithms including Multilayer Perceptron, Linear Logistic Regression, k-nearest Neighbors, Naïve Bayes, and Random Forest were trained on this dataset. Several metrics were used for the evaluation of accuracy, precision, recall, and kappa statistic. The most important 12 features were determined with the feature selection algorithm. While all algorithms achieved over 90% accuracy, Random Forest yielded 95% accuracy, with high reliability values (kappa = 0.90). The employment of machine learning methods for the treatment decision with or without extraction in the early treatment of patients in the mixed dentition can be particularly useful for pedodontists and general practitioners.

A Comparative Evaluation of Mandibular Intercanine Arch Width Changes in Class I and Class II Division 1 Malocclusions Treated with Extraction— An Occlusogram Study

A Comparative Evaluation of Mandibular Intercanine Arch Width Changes in Class I and Class II Division 1 Malocclusions Treated with Extraction— An Occlusogram Study

Abstract PO-049: The neural landscape is associated with functional outcomes for patients with oropharyngeal squamous cell carcinoma

Abstract Despite the excellent prognosis of patients with oropharyngeal squamous cell carcinoma (OPSCC), long-term functional impairment (e.g., dysphagia) is a major burden for many patients. Recent studies have explored the role of pharyngeal constrictors and muscle fibrosis in dysphagia. However, to date, no study has examined the association between the OPSCC neural microenvironment and posttreatment functional impairment. We hypothesized that cancer-related neuronal changes in the OPSCC tumor microenvironment (TME) would affect patients’ prognoses. Therefore, in the present study, we investigated whether cancer-related changes in the tumor neuronal microenvironment influence functional outcomes in patients with OPSCC. Prospectively collected, patient-reported outcomes (i.e., from the MD Anderson Symptom Inventory [MDASI] and the MD Anderson Dysphagia Inventory [MDADI]) and functional outcomes from the Dynamic Imaging Grade of Swallowing Toxicity [DIGEST] for patients with OPSCC were collected (n=29). OPSCC tissue samples were obtained from surgically treated patients, and multiplex/high-plex immunofluorescence and machine learning techniques were used to correlate neuronal changes with prospectively collected patient data. Electromyography was performed to assess the neuronal populations involved in neuropathies after treatment. A murine animal model of dysphagia was also used to correlate the neuronal changes. The results showed that sensory nerves with adrenergic features (CGRP+TH+) were associated with perineural and lymphovascular invasion. In addition, we found that human papillomavirus associated OPSCC was associated with an enrichment of parasympathetic progenitors (VIP+DCX+). Poor MDASI scores were associated with CGRP+, adrenergic (TH+), or CGRP+TH+ innervation, and growing progenitor neurons (GAP43+DCX+) were associated with improved oral symptoms. Swallowing, measured by MDADI scale revealed that patients with tumors enriched with growing (GAP43+), parasympathetic (VIP+), and neuronal progenitor (DCX+) neurons reported poor swallowing perception; subgroup electromyography analysis confirmed our findings. Quantitative swallowing assessment with DIGEST by speech language pathologists revealed that TMEs innervated by CGRP+, TH+, and MBP+ neurons were associated with poor swallowing functions. Finally, using a murine model of dysphagia we confirmed that sensory (CGRP+), myelinated (MBP+), and cholinergic parasympathetic (CHAT+) or progenitor (CHAT+DCX+) enrichment was associated with denervation and downstream dysphagia. In conclusion, our results show that neuronal changes are correlated with clinical features in OPSCC patients. Patients’ functional outcomes after therapy completion are influenced by distinct nerve populations in the TME. These benchmark data should be further evaluated as a potential target for cancer survivors with dysphagia and as a biomarker for patients who might need escalated swallowing rehabilitation during and after treatment for OPSCC. Citation Format: Shajedul Islam, Frederico O. Gleber-Netto, Collin F. Mulcahy, Mica D. E. Glaun, Patrick J. Hunt, Michelle D. Williams, Carly E. Barbon, Weilu Zhao, Adewale Adebayo, Shamima Akhter, Tongxin Xie, Ismail Yaman, Jared K. Burks, Javier Gomez, Karin Woodman, Teresa E. Lever, Katherine A. Hutcheson, Moran Amit. The neural landscape is associated with functional outcomes for patients with oropharyngeal squamous cell carcinoma [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr PO-049.

Reversible cardiac function and left ventricular hypertrophy in a Chinese man with mitochondrial myopathy: a case report

BackgroundMitochondrial myopathies (MMs) are a group of multi-system diseases caused by abnormalities in mitochondrial DNA (mtDNA) or mutations of nuclear DNA (nDNA). The diagnosis of mitochondrial myopathy (MM) is reliant on the combination of history and physical examination, muscle biopsy, histochemical studies, and next-generation sequencing. Patients with MMs have diverse clinical manifestations. In the contemporary literature, there is a paucity of reports on cardiac structure and function in this rare disease. We report a Chinese man with MM accompanied with both acute right heart failure and left ventricular hypertrophy.Case presentationA 49-year-old man presented with clinical features suggestive of MM, i.e., ophthalmoparesis, weakness of the pharyngeal and extremity muscles, and respiratory muscles which gradually progressed to respiratory insufficiency. He had a family history of mitochondrial myopathy. He had increased levels of serum creatine kinase and lactate. Muscle biopsy of left lateral thigh revealed 8% ragged red fibers (RRF) and 42% COX-negative fibers. Gene sequencing revealed a novel heterozygote TK2 variant (NM_001172644: c.584T>C, p.Leu195Pro) and another heterozygous variant (NM_004614.4:c.156+958G>A; rs1965661603) in the intron of TK2 gene. Based on these findings, we diagnosed the patient as a case of MM. Echocardiography revealed right heart enlargement, pulmonary hypertension, left ventricular hypertrophy, and thickening of the main pulmonary artery and its branches. The patient received non-invasive ventilation and coenzyme Q10 (CoQ10). The cardiac structure and function were restored at 1-month follow-up.ConclusionsThis is the first report of reversible cardiac function impairment and left ventricular hypertrophy in a case of adult-onset MM, nocturnal hypoxia is a potential mechanism for left ventricular hypertrophy in patients with MM.