Mandibular Arch Research Articles

Internal Carotid Artery:Development and Anomalies

This chapter outlines the cerebrovascular developmental anatomy with emphasis on the internal carotid artery(ICA), which is important for optimal endovascular treatment of cerebrovascular system disorders. Gene expression, neural crest cells, and pharyngeal arches play key roles in the embryonic development of the carotid arteries. Evolutionary inheritance in vertebrates contributes to the formation, regression, and segmental structure of these arteries. We present examples of current mutations with regard to their segmental nature; ICA mutations are discussed primarily with regard to their developmental origin from the first to third pharyngeal arches and the role of the ductus caroticus. This comprehensive review highlights the importance of understanding the developmental and anatomical nuances of the ICA to aid with accurate diagnosis and management of vascular anomalies in the clinical setting. We have focused on the complexity associated with ICA mutations, particularly those associated with the third pharyngeal arch and the need for a solid foundation of developmental and anatomical knowledge to accurately identify and interpret their significance in the adult phenotype.

Optimizing pier abutment management using digital approach with nonrigid connector for superior treatment outcomes

Abstract In clinical dental practice, missing the first premolar and first molar are a common finding in the maxillary or mandibular arch. The result is a long bridge span in which the canine and the second molar act as terminal abutments and the second premolar act as a pier abutment. Teetering movements are usually observed due to the inclination of terminal abutments intruding during function, with the pier abutment serving as a pivot point. Due to these dislodging forces, the rigid fixed dental prosthesis (FDP) with pier abutment has a higher debonding rate than short-span prosthesis, resulting in marginal leakage and caries. This situation can be avoided using nonrigid connectors that act as stress breakers between the retainer and the pontic. This report describes incorporating a digitally fabricated nonrigid connector to rehabilitate a pier abutment case.

Piezo1 and Piezo2 collectively regulate jawbone development.

Piezo1 and Piezo2 are recently reported mechanosensory ion channels that transduce mechanical stimuli from the environment into intracellular biochemical signals in various tissues and organ systems. Here, we show that Piezo1 and Piezo2 display a robust expression during jawbone development. Deletion of Piezo1 in neural crest cells causes jawbone malformations in a small but significant number of mice. We further demonstrate that disruption of Piezo1 and Piezo2 in neural crest cells causes more striking defects in jawbone development than any single knockout, suggesting essential but partially redundant roles of Piezo1 and Piezo2. In addition, we observe defects in other neural crest derivatives such as malformation of the vascular smooth muscle in double knockout mice. Moreover, TUNEL examinations reveal excessive cell death in osteogenic cells of the maxillary and mandibular arches of the double knockout mice, suggesting that Piezo1 and Piezo2 together regulate cell survival during jawbone development. We further demonstrate that Yoda1, a Piezo1 agonist, promotes mineralization in the mandibular arches. Altogether, these data firmly establish that Piezo channels play important roles in regulating jawbone formation and maintenance.

Metallic vs Ceramic Bracket Failures After 12 Months of Treatment: A Prospective Clinical Trial

IntroductionOrthodontic treatment with fixed vestibular appliances is still widely used worldwide. When choosing the aesthetic alternative of ceramic brackets, the possibility of failure and cracking of braces should be considered. Therefore, the aim of the present study was to compare the failure rates of ceramic and metal brackets in a 12-month clinical study. MethodsEighty patients undergoing fixed orthodontic treatment with vestibular appliances were enrolled and divided into 2 equal groups: MET for metal brackets and CER for ceramic brackets. After bonding, bracket failures were recorded for 12 months, along with the archwire placed at the time of failure. Angle's dental class, skeletal class, Wits appraisal, Little's irregularity index, overjet, overbite, age, and gender of the patients were recorded from pretreatment cephalometric tracings and study casts. The data were statistically analysed (P < .05). ResultsSignificantly higher failure rates were found for ceramic brackets in the overall analysis, in the mandibular arch, and in the posterior region. Regression analysis revealed a significant influence of round nickel-titanium archwires on higher failure rates, whilst a significant influence of rectangular archwires was found on lower failure rates. ConclusionsCeramic brackets showed higher failure rates. Patients should be aware that orthodontic treatment with ceramic brackets may involve delays and inconvenience due to the higher failure rate compared to metal brackets.

Aortic Arch:Embryology and Remodeling

A right aortic arch and aberrant subclavian artery result from an interruption in the remodeling of the pharyngeal arch arteries. We occasionally encounter this anatomical variation during angiography. Patients with disorders such as Down syndrome and congenital heart disease show a high incidence of an aberrant right subclavian artery, and this anomaly can cause symptomatic esophageal or tracheal compression. The root of the aberrant artery may show dilatation(referred to as a Kommerell diverticulum), dissection, intramural hematoma, or rupture necessitating cardiac intervention using a surgical or endovascular approach. Neurointerventionalists should have working knowledge of the anatomy to rapidly understand the anatomy and ensure a safe procedure. A left transradial approach should be considered if prior knowledge of the aberrant subclavian anatomy is available.

The role of the soft palate dose regarding normal tissue toxicities in older adults with head and neck cancer undergoing definitive radiotherapy.

The number of older adults with head and neck squamous cell carcinoma (HNSCC) is continuously increasing. Older HNSCC patients may be more vulnerable to radiotherapy-related toxicities, so that extrapolation of available normal tissue complication probability (NTCP) models to this population may not be appropriate. Hence, we aimed to investigate the correlation between organ at risk (OAR) doses and chronic toxicities in older patients with HNSCC undergoing definitive radiotherapy. Patients treated with definitive radiotherapy, either alone or with concomitant systemic treatment, between 2009 and 2019 in a large tertiary cancer center were eligible for this analysis. OARs were contoured based on international consensus guidelines, and EQD2 doses using α/ß values of 3Gy for late effects were calculated based on the radiation treatment plans. Treatment-related toxicities were graded according to Common Terminology Criteria for Adverse Events version 5.0. Logistic regression analyses were carried out, and NTCP models were developed and internally validated using the bootstrapping method. A total of 180 patients with a median age of 73 years fulfilled the inclusion criteria and were analyzed. Seventy-three patients developed chronic moderate xerostomia (grade 2), 34 moderate dysgeusia (grade 2), and 59 moderate-to-severe (grade 2-3) dysphagia after definitive radiotherapy. The soft palate dose was significantly associated with all analyzed toxicities (xerostomia: OR = 1.028, dysgeusia: OR = 1.022, dysphagia: OR = 1.027) in the multivariable regression. The superior pharyngeal constrictor muscle was also significantly related to chronic dysphagia (OR = 1.030). Consecutively developed and internally validated NTCP models were predictive for the analyzed toxicities (optimism-corrected AUCs after bootstrapping: AUCxerostomia=0.64, AUCdysgeusia=0.60, AUCdysphagia=0.64). Our data suggest that the dose to the soft palate is associated with chronic moderate xerostomia, moderate dysgeusia and moderate-to-severe dysphagia in older HNSCC patients undergoing definitive radiotherapy. If validated in external studies, efforts should be undertaken to reduce the soft palate dose in these patients.

Functional and Genetic Analyses Unveil the Implication of CDC27 in Hemifacial Microsomia.

Hemifacial microsomia (HFM) is a rare congenital genetic syndrome primarily affecting the first and second pharyngeal arches, leading to defects in the mandible, external ear, and middle ear. The pathogenic genes remain largely unidentified. Whole-exome sequencing (WES) was conducted on 12 HFM probands and their unaffected biological parents. Predictive structural analysis of the target gene was conducted using PSIPRED (v3.3) and SWISS-MODEL, while STRING facilitated protein-to-protein interaction predictions. CRISPR/Cas9 was applied for gene knockout in zebrafish. In situ hybridization (ISH) was employed to examine the spatiotemporal expression of the target gene and neural crest cell (NCC) markers. Immunofluorescence with PH3 and TUNEL assays were used to assess cell proliferation and apoptosis. RNA sequencing was performed on mutant and control embryos, with rescue experiments involving target mRNA injections and specific gene knockouts. CDC27 was identified as a novel candidate gene for HFM, with four nonsynonymous de novo variants detected in three unrelated probands. Structural predictions indicated significant alterations in the secondary and tertiary structures of CDC27. cdc27 knockout in zebrafish resulted in craniofacial malformation, spine deformity, and cardiac edema, mirroring typical HFM phenotypes. Abnormalities in somatic cell apoptosis, reduced NCC proliferation in pharyngeal arches, and chondrocyte differentiation issues were observed in cdc27-/- mutants. cdc27 mRNA injections and cdkn1a or tp53 knockout significantly rescued pharyngeal arch cartilage dysplasia, while sox9a mRNA administration partially restored the defective phenotypes. Our findings suggest a functional link between CDC27 and HFM, primarily through the inhibition of CNCC proliferation and disruption of pharyngeal chondrocyte differentiation.

Manufacturing of PEEK orthodontic baseplate and 3D-printed alloy components from an intraoral scan.

This paper demonstrates a digital manufacturing technique of a removable orthodontic appliance from an intraoral scan. An intraoral scan was made for the maxillary and mandibular arches. 3Shape Orthodontics Appliance Designer produced the virtual Hawley retainer, consisting of alloy components (Adam Clasps and Fitted Labial bow) and a base plate. The base plate design was modified to adapt to inserting the alloy components, which were combined using cold-cured acrylic. The finished Hawley retainer was assessed intraorally. The described technique emphasizes the design specifications of digitally designed and manufactured removable orthodontic appliances. A combination of additive and subtractive techniques was successfully employed to manufacture the alloy components and base plate. This novel method provides an alternative approach to manufacturing removable appliances with computer-aided design (CAD)/computer-aided manufacturing (CAM) technologies. The described process offers a precursor to digital manufacturing of other developed designs of dental appliances.

The chondrocranium of the tadpole of Hymenochirus boettgeri (Anura: Pipidae) and the sequence and timing of its development

The evolutionary development of the vertebrate head has played a critical role in shaping the diversity of body plans and ecological roles within vertebrate species. This evolutionary journey is characterised by the emergence of the head compartment during the Cambrian radiation, the evolution of jaws during the Silurian, and the subsequent diversification of vertebrate groups. The cranium, consisting of the neurocranium, dermatocranium, and viscerocranium, plays a central role in craniofacial support. Research on the development of the cranium has been carried out in several vertebrate species, providing valuable insights into their unique patterns of cartilage development. While most vertebrates show typical sequences of chondrocranial development, anurans divert from these patterns. Our study focused on the chondrocranial development of Congo dwarf frog Hymenochirus boettgeri (Anura: Pipidae) tadpoles, providing a detailed sequential analysis from mesenchymal elements to the premetamorphic chondrocranium. The chondrocranium of these tadpoles showed several reductions as a consequence of their miniaturization and their unique suction feeding lifestyle. We found a mosaic-like development of anuran mandibular and hyoid arches, and we also discussed the intricate patterns of suprarostral cartilage development and deviations in branchial basket development compared to other anuran species. Our study also contrasts anuran neurocranial development with that of other osteichthyan species, highlighting unique features such as the similar direction of development of anterior and posterior neurocranial components. Overall, our research contributes to our understanding of chondrocranial development in anurans, highlighting both conserved and unique features in H. boettgeri tadpoles. Our findings enrich our knowledge of vertebrate cranial development and provide insights into the evolutionary history of anuran chondrocranial features.

In vitro study examines posterior torque impact on 3D mechanics of anterior teeth in clear aligner treatment

IntroductionThis study utilizes investigate the impact of posterior torques on the three-dimensional force exerted on the lower anterior teeth during the retraction in orthodontic clear aligners treatment.MethodsFour groups of mandibular dental arch light-cured resin models will be created, including: mandibular posterior teeth with standard torque, mandibular posterior teeth with labial torque, and mandibular posterior teeth with lingual torque. Each group will consist of 12 sets of clear aligners. The aligners will be worn, and measurements will be taken using the six-axis measurement platform to evaluate the three-dimensional force exerted on the lower anterior teeth under various initial torques applied to the mandibular posterior teeth. SPSS 26.0 used for ANOVA analysis, α = 0.05 significance level.ResultsComparing mandibular posterior teeth with standard torque to those with labial torque, no statistically significant changes were observed in buccolingual force. In the mesiodistal direction, mandibular incisors exhibited a significant decrease in distal force, while canines showed a significant increase. Both findings had a significance level of P < 0.05; Lingual torque on mandibular posterior teeth, compared to standard torque, led to a significant increase in lingual force for incisors and a significant increase in labial force for canines in the buccolingual direction (P < 0.05). Additionally, mandibular incisors exhibited a significant decrease in distal force in the mesiodistal direction (P < 0.05).ConclusionVarying initial torques on mandibular posterior teeth significantly impact force on lower anterior teeth. Labial torque reduces lingual force on incisors and increases distal force on canines. Lingual torque increases lingual force on incisors and labial force on canines.

To Evaluate the Relationship between Maxillary and Mandibular Base Lengths with Dental Crowding in Different Skeletal Malocclusions

Introduction Exploring the relationship between arch dimensions and crowding has long been a topic of interest. Many studies have found significant relationship between the two, while others have suggested that crowding is a multifactorial condition and is not dependent on arch dimensions only. Objective To evaluate the relationship as well as sexual dimorphism between maxillary and mandibular skeletal base lengths with dental crowding in different skeletal malocclusions. Materials and Methods The sample comprised 100 orthodontic patients (49 males, 51 females), which were divided into three groups based on the anteroposterior relationship of maxilla with the mandible. Each group was subdivided based on the severity of mandibular and maxillary arch crowding into two subgroups, and each subgroup was further divided into male and female subjects. Measurements of maxillary and mandibular base lengths (Co-A and Co-Gn) and tooth size arch length discrepancies were obtained through lateral cephalograms and dental casts, respectively, and measurements obtained were analyzed statistically. Results Patients with class IB, IIB, and IIIB had significantly smaller maxillary and mandibular base lengths than subjects with class IA, IIA, and IIIA. A weak negative correlation was found between maxillary base length and maxillary crowding with r = –0.451 and p = .000, while a strong positive correlation was observed between maxillary and mandibular crowding with r = 0.742 and p = .000. Conclusion An inverse correlation exists between dental crowding and the lengths of maxillary and mandibular bases, regardless of skeletal malocclusion.

Spontaneous Mandibular Dentoalveolar Changes after Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander-A Systematic Review.

This systematic review aims to analyze the spontaneous dentoalveolar changes in the mandibular arch after maxillary expansion in growing patients obtained with different expansion protocols: Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander. The study adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Eligibility criteria were established in the PICO format, involving patients who underwent slow, rapid, or leaf maxillary expansion during the mixed or early permanent dentitions. A comprehensive search of electronic databases and manual searches was conducted up to December 2023. The outcome measures included inter-mandibular first permanent molar width, inter-deciduous molar and canine width, arch perimeter, and arch length; both short- and long-term results were considered. The articles that met the inclusion criteria were included in this systematic review and were qualitatively evaluated using a methodological quality scoring system with a 13-point scale. To assess the inter-examiner agreement concerning the article selection and the qualitative assessment of the included studies, Kappa statistics were computed. A total of 1184 articles were identified through electronic and manual searches. After the removal of duplicates and the initial examination of the titles and abstracts, 57 articles were considered for the full text analysis, and according to the eligibility and exclusion criteria, 22 studies were finally selected, composed of 8 randomized controlled trials (RCTs) and 14 retrospective/case-control studies. The qualitative assessment of the included studies showed the following scores: 6 papers have high research quality, 5 have moderate quality, and 11 have low quality. SME demonstrated negligible mandibular changes, with less than 1 mm variation on average (range 0.46-2.00 mm) in the selected parameters and relapses observed in the long term. RME induced more significant increases, particularly in intermolar width greater than 1 mm, which ranged between 0.93 and 3.3 mm, and good stability over the long term. Leaf Expander exhibited promising short-term lower intermolar width increases greater than 1 mm and ranged from 0.5 to 1.69 mm, but long-term stability was not thoroughly evaluated. SME results in negligible short- and long-term effects, while RME, especially with Haas-type appliances, exhibits significant intermolar width increases that remain stable over the years. Leaf Expander shows short-term lower intermolar width increases, requiring further investigation into long-term stability.

Acto3D: an open-source user-friendly volume rendering software for high-resolution 3D fluorescence imaging in biology.

Advances in fluorescence microscopy and tissue-clearing have revolutionised 3D imaging of fluorescently labelled tissues, organs and embryos. However, the complexity and high cost of existing software and computing solutions limit their widespread adoption, especially by researchers with limited resources. Here, we present Acto3D, an open-source software, designed to streamline the generation and analysis of high-resolution 3D images of targets labelled with multiple fluorescent probes. Acto3D provides an intuitive interface for easy 3D data import and visualisation. Although Acto3D offers straightforward 3D viewing, it performs all computations explicitly, giving users detailed control over the displayed images. Leveraging an integrated graphics processing unit, Acto3D deploys all pixel data to system memory, reducing visualisation latency. This approach facilitates accurate image reconstruction and efficient data processing in 3D, eliminating the need for expensive high-performance computers and dedicated graphics processing units. We have also introduced a method for efficiently extracting lumen structures in 3D. We have validated Acto3D by imaging mouse embryonic structures and by performing 3D reconstruction of pharyngeal arch arteries while preserving fluorescence information. Acto3D is a cost-effective and efficient platform for biological research.

Buffering Mechanism in Aortic Arch Artery Formation and Congenital Heart Disease.

The resiliency of embryonic development to genetic and environmental perturbations has been long appreciated; however, little is known about the mechanisms underlying the robustness of developmental processes. Aberrations resulting in neonatal lethality are exemplified by congenital heart disease arising from defective morphogenesis of pharyngeal arch arteries (PAAs) and their derivatives. Mouse genetics, lineage tracing, confocal microscopy, and quantitative image analyses were used to investigate mechanisms of PAA formation and repair. The second heart field (SHF) gives rise to the PAA endothelium. Here, we show that the number of SHF-derived endothelial cells (ECs) is regulated by VEGFR2 (vascular endothelial growth factor receptor 2) and Tbx1. Remarkably, when the SHF-derived EC number is decreased, PAA development can be rescued by the compensatory endothelium. Blocking such compensatory response leads to embryonic demise. To determine the source of compensating ECs and mechanisms regulating their recruitment, we investigated 3-dimensional EC connectivity, EC fate, and gene expression. Our studies demonstrate that the expression of VEGFR2 by the SHF is required for the differentiation of SHF-derived cells into PAA ECs. The deletion of 1 VEGFR2 allele (VEGFR2SHF-HET) reduces SHF contribution to the PAA endothelium, while the deletion of both alleles (VEGFR2SHF-KO) abolishes it. The decrease in SHF-derived ECs in VEGFR2SHF-HET and VEGFR2SHF-KO embryos is complemented by the recruitment of ECs from the nearby veins. Compensatory ECs contribute to PAA derivatives, giving rise to the endothelium of the aortic arch and the ductus in VEGFR2SHF-KO mutants. Blocking the compensatory response in VEGFR2SHF-KO mutants results in embryonic lethality shortly after mid-gestation. The compensatory ECs are absent in Tbx1+/- embryos, a model for 22q11 deletion syndrome, leading to unpredictable arch artery morphogenesis and congenital heart disease. Tbx1 regulates the recruitment of the compensatory endothelium in an SHF-non-cell-autonomous manner. Our studies uncover a novel buffering mechanism underlying the resiliency of PAA development and remodeling.

Digital setup accuracy for moderate crowding correction with fixed orthodontic appliances: a prospective study

ObjectivesTo evaluate the accuracy of a semi-automatic 3D digital setup process in predicting the orthodontic treatment outcome achieved by labial fixed appliances.Subjects and MethodsTwenty-five adult patients (18 to 24 years old) with class I malocclusion and moderate crowding were prospectively enrolled and received treatment on both jaws through the straight-wire technique. Prior to treatment commencement, a semi-automatic digital setup simulating the predicted treatment outcome was performed for each patient through Orthoanalyzer software (3Shape®, Copenhagen, Denmark) to obtain the prediction model. This was compared to the final outcome model through 3D superimposition methods. Metric variables and inspection of color-coded distance maps were used to detect how accurately the digital setup predicts the actual treatment outcome.ResultsThe mean absolute distances (MAD) between the superimposed dental arches of the predicted and the final models were: 0.77 ± 0.13 mm following superimposition on the palate, 0.52 ± 0.06 mm following superimposition on the maxillary dental arch, and 0.55 ± 0.15 mm following superimposition on the mandibular dental arch. The MAD at the palatal reference area was 0.09 ± 0.04 mm. Visualization of color-coded distance maps indicated that the digital setup accurately predicted the final teeth position in a few cases. Almost half of the cases had posteriorly wider upper and lower dental arches and palatally/lingually positioned or inclined anterior teeth, whereas the rest still showed errors within 2–3 mm, distributed over the entire dental arches with no distinct pattern.ConclusionsThe accuracy of semi-automatic prediction of the labial fixed appliance treatment outcome in Class I cases with moderate crowding is not yet sufficient. While average measures showed deviations less than 1 mm, examination of individual color-coded distance maps revealed significant disparities between the simulated and the actual results.

Prospective cohort study on facial profile changes in infants with Robin sequence and healthy controls

BackgroundVarious conservative and surgical approaches exist to treat Robin sequence (RS), but their effects on facial profile and mandibular catch-up growth are unclear. A functional treatment concept, used in our centre for 25 years, includes an individualized palatal plate with a velo-pharyngeal extension and intensive feeding training.MethodsWe performed a prospective study to objectively describe facial profiles in infants with RS treated with the above concept. Infants with isolated RS were admitted to our tertiary perinatal and national referral centre for craniofacial malformations between May 2018 and Nov 2019. Infants with RS received 3D-photographs during clinically indicated visits. Healthy controls were recruited from Dec 2018 to Sep 2019 and received 3D-photographs every 3 months. The digitally measured jaw index (JI), defined as alveolar overjet (O) x maxillary arch (U)/mandibular arch (L), and the soft tissue reference points A’-point, Nasion’, B’-point angle (ANB’), describing the relative position of maxilla to mandible, were evaluated. Linear mixed models were used to examine time trajectories in JI and ANB’.ResultsA total of 207 3D images, obtained in 19 infants with RS and 32 controls, were analysed. JI and ANB’ decreased over time in both groups [for JI − 0.18 (95% CI − 0.25 to − 0.10); for ANB’: − 0.40° per month [(95% CI − 0.48 to − 0.32)]] but remained lower in controls [for JI − 2.5 (95% CI − 3.2 to − 1.8); for ANB’-1.7° (95% CI − 2.4 to − 1.0)]. Also, the ANB’ model showed a significant effect of the interaction term diagnosis x age.ConclusionsBased on longitudinal 3D images, we describe changes in objective parameters of facial profile in infants with and without RS during the first year of life. Our findings indicate catch-up growth in infants treated for RS.4YQYEi2Zb5vMP7WQ-MbtxwVideo

Comparison of traditional and mobile photogrammetric method for the Tanaka Johnston mixed dentition analysis: an analytical cross-sectional study

Aim Comparison of Tanaka Johnston mixed dentition analysis using the mobile photogrammetric method and traditional method. Patients and methods Thirty-five healthy children between the ages of 6 and 10 were signed up for the study. Casts were considered using the conventional Tanaka Johnston analysis method. A digital caliper was utilized to measure the mesiodistal dimension of every tooth from the incisor to the first permanent molar on both sides. Occlusal photos were taken intraorally using a smartphone and an intraoral occlusal mirror. The principal investigator took the intraoral pictures. An assistant retracted the lips and placed the intraoral mirror inside the mouth. The acquired images were exported to the digimizer software, where they were processed and analyzed. To enable digital software to measure dental arch images, an occlusal ruler was kept at the occlusal level. A total of 20 tooth measurements in the maxillary and mandibular arches were taken for the Tanaka Johnston mixed dentition analysis. Results Thirty-five children were assessed. Intergroup comparison of different parameters between two groups was performed. This comparison revealed no statistically significant differences (P value &gt; 0.05) between the traditional and photogrammetric methods for all parameters, indicating that both methods produce similar outcomes. Conclusion The photogrammetric method is a reliable and valid method to measure individual tooth width. The photogrammetric method is alternative to traditional method for Tanaka Johnston mixed dentition analysis.

Sparing Swallowing-Related Structures Reduces Post-Radiotherapy Dysphagia in Oropharyngeal Cancer.

To identify swallowing-related structures (SRSs) predicting post-radiotherapy dysphagia in oropharyngeal carcinoma patients. Between September 2020 and October 2022, oropharyngeal cancer patients who had completed radiotherapy at least one year before without recurrence or residuals were selected. They underwent flexible endoscopic evaluation of swallowing (FEES) assessments and dysphagia grading. The mean radiation doses delivered to their SRSs were recalculated. The correlation between radiation doses to each SRS and FEES scores was analysed. Twenty-nine participants, aged 51-73 years, were enrolled. Six patients had received two-dimensional radiotherapy, eight had undergone three-dimensional conformal radiotherapy, and fifteen had received intensity-modulated radiation therapy. Radiation doses to the inferior pharyngeal constrictor, cricopharyngeus and glottic larynx significantly predicted dysphagia for both semisolids (p = 0.023, 0.030 and 0.001) and liquid diets (p = 0.021, 0.013 and 0.002). The esophageal inlet significantly predicted swallowing outcomes for only the liquid diet (p = 0.007). This study supports that SRS-sparing during radiotherapy for oropharyngeal cancers improves swallowing outcomes.

Mandibular Interincisor and Intercanine Width at Three Different Stages of Dentition: A Cross-sectional Study.

Malocclusion is a manifestation of normal biological variability, defined as a misalignment of the teeth or an incorrect occlusion between the upper and lower dental arches. This study aimed to evaluate the mandibular intercanine primary, mixed, and permanent dentition in school children of Shimla, Himachal Pradesh. This cross-sectional study was conducted on 1,392 children between the ages of 4 and 18 years from schools that fulfilled the inclusion criteria. The dental casts were poured and further divided based on the dentition stage, i.e., primary, mixed, and permanent dentition stages. Mandibular arch widths-interincisor and intercanine were measured on the casts by a digital vernier caliper. The statistically significant difference was found as the interincisor width increased from primary to mixed dentition and between males and females for permanent dentition. Intercanine width significantly increases from primary to mixed dentition and gradually from mixed to permanent dentition stages. The present study found that there is a significant increase in interincisor and intercanine width in the lower dental arch from primary dentition to permanent dentition. Singhal P, Jaswal O, Thakur S. Mandibular Interincisor and Intercanine Width at Three Different Stages of Dentition: A Cross-sectional Study. Int J Clin Pediatr Dent 2024;17(4):417-424.

Radiographic Assessment Regarding the Pattern of Third Molar Impaction and its Association with Gender in the Population of Islamabad

Abstract &#x0D; Objective: To analyze and document the gender-specific incidence of impacted third molars and elucidate the specific patterns associated with impacted third molars.&#x0D; Methodology: This retrospective cross-sectional study analyzed orthopantomograms (OPG) data from 278 patients, covering a total of 445 impacted third molars. A convenient sampling technique was used and the study was completed in three months from September 2023 and December 2023, Inclusion criteria: OPGs of individuals aged 25 years or older with fully formed third molar roots, Exclusion criteria: OPGs of individuals younger than 25, with craniofacial anomalies, prior orthodontic treatment, erupted third molars, or incomplete root formation in third molars.&#x0D; Results: Both males and females were almost equal in number. The majority 73.2% of OPG showed mandibular third molar impaction while 26.8% showed maxillary third molar impaction. In the maxillary arch, the distoangular type of impaction was observed in the majority, accounting for 48.7%. In the mandibular arch, mesioangular impaction prevailed, comprising 41.7%. In the maxillary arch, a statistically significant correlation (p=0.006) was found between gender and impaction type, with females exhibiting a distinct and more prevalent impaction pattern than males. In the mandibular arch, there was no statistically significant association between gender and impaction type (p=0.23).&#x0D; Conclusion: In conclusion, our study reveals noteworthy gender variations in the prevalence and types of third molar impactions. Mandibular third molars exhibit a higher prevalence than maxillary counterparts, with mesioangular impaction prevailing in the mandibular arch and distoangular impaction in the maxillary arch.