Dorsum Of Tongue Research Articles

Rare Case of Squamous Cell Carcinoma of Midline Dorsum of Tongue: Diagnostic and Management Dilemma.

Squamous cell carcinoma is the most common carcinoma of the tongue. However, the majority of carcinoma originates in the lateral border of the tongue and midline dorsum only represents about 2-5% of tongue cancer patients. We present a rare case of squamous cell carcinoma in a 59 years old male patient originating in the midline dorsum of tongue and the management dilemma.

Assessment of Posterior Pharyngeal Airway Changes After Orthognathic Surgery Using Barium Sulfate.

Obstructive sleep apnea(OSA), caused by airway narrowing, is likely to occur if the mandibular plane to hyoid distance is greater than 15.4 mm and the posterior airway space (PAS) is less than 11 mm. OSA may be caused by mandibular deficit, bimaxillary retrusion, increased lower facial height, extended soft palate, a large tongue base, and a posteroinferiorly positioned hyoid bone. Snoring and drowsiness during exercise are symptoms of OSA, which is a risk factor for high blood pressure, heart disease, and stroke, and these can result in car crashes. However, orthognathic surgery can improve dental occlusion and aesthetics by adjusting facial bone position, shape, and size. When bones move, the position and tension of soft tissues change. These novel soft tissue interactions, especially when anteroposterior, change the face's appearance and PAS dimensions. This study uses barium sulfate paste to enhance lateral cephalograms before and after orthognathic surgery to assess posterior pharyngeal airway changes. Barium sulfate was mixed with water to make a paste for the tongue's dorsum. A preoperative digital lateral cephalogram was obtained, and a postoperative evaluation was conducted six weeks after the procedure. In the cephalostat, the Frankfort horizontal and median planes were aligned parallel to the floor, and a radiograph was taken after the breathing cycle to standardize the hyoid bone location. Preoperative lateral cephalogram analysis using Burstone's hard tissue landmarks confirmed skeletal class II or III deformities. First, the narrowest part of the posterior pharyngeal airway was measured. Second, the narrowest portion between the soft palate and posterior pharyngeal wall parallel to the Frankfort horizontal plane was measured preoperatively, and the procedure was repeated six weeks postop. Complexity characterizes the pharyngeal airway, which, along with the surrounding structures, facilitates the bodily functions of eating, talking, and breathing. The pharyngeal airway is located behind the nose, mouth, and larynx, and adjusting the jaws changes the size and structure of the pharyngeal airway and surrounding soft tissues, which may affect breathing.A statistically significant change is detected in the posterior palatal and posterior lingual airways after different orthognathic operations. After the mandible is moved forward, both the posterior palatal and posterior lingual airways enlarge. Furthermore, the soft palate exhibits slight decreases in length, thickness, and angle. Additionally, there is an anterosuperior displacement of the hyoid bone. Following maxillary superior impaction, mandibular autorotation is seen in a counterclockwise direction, which has the same result as that of mandibular advancement. It is essential to consider these soft tissue changes when planning orthognathic procedures, as alterations in the pharyngeal airway may impact the patient's postoperative breathing and overall health. Patients with OSA or those at risk of developing it should be closely evaluated and managed appropriately during the surgical planning process.

Molecular docking study of hyaluronic acid against interleukin-6 (7DC8 protein) in COVID-19 patients with periodontitis

Coronavirus disease 2019 (COVID-19) is a new disease caused by a coronavirus, namely SARS-CoV-2. This virus was entered inside the host by angiotensin-converting enzyme receptors (ACE2). Recent evidence suggests that sulcus fluid in the periodontal pockets of patients with periodontitis may be a source of SARS-CoV-2 and a potential reservoir for increasing oral viral load in patients with confirmed COVID-19. ACE-2 is expressed in stratified squamous epithelium mainly on the dorsal tongue and gingiva. The gingival sulcular epithelium is the entry point for SARS-CoV-2 into the periodontal pocket epithelium through the gingival crevicular fluid (GCF). Hyaluronic acid (HA) is a high molecule of heavy polysaccharide (glycosaminoglycan) which has several functions, such as anti-inflammatory and accelerated wound healing. It could decrease the levels of several cytokines. This study aims to analyze the interaction of HA against the IL-6 coronavirus receptor in periodontitis through a molecular docking study using MOE 2015.10 software with IL-6 receptor (7DC8) as the protein model to predict the binding of HA with 10 poses. The 7DC8 protein was prepared by adding charge and the validation method was performed with RMSD <2Å which indicates this method is valid. The results of this study showed that there are interaction between HA and the IL-6 receptor via amino acid residue interaction at the Leucine 98 (bond energy -0.7 kcal/mol), Serine 52 (bond energy -1.7 kcal/mol), Glycine 53 (bond energy -1.5 kcal/mol), and Glycine 299 (bond energy -1.6 kcal/mol). HA has an interaction with coronavirus at the IL-6 receptor of periodontitis based on molecular docking study and can potentially be used as a therapeutic option in COVID-19 with periodontitis. In conclusion, hyaluronic acid has the potential as an anti-inflammatory drug of choice in COVID-19 patients with periodontitis.

Schwannoma of oral tongue

Schwannomas also known as Neurilemmoma, are benign encapsulated slow growing tumors, which arise from Schwann cells of the peripheral nerve sheath. They usually occur in the head and neck region, but rarely in the oral cavity. We report a case of Schwannoma of the oral tongue in a 49-year-old male patient, who presented with a slow growing, painless lesion involving left side of the dorsum of the oral tongue. Patient underwent Magnetic Resonance Imaging with contrast followed by complete surgical excision. Histopathological and Immunohistochemical examination confirmed the diagnosis.

An Automatic Method for Sublingual Image Segmentation and Color Analysis.

Automatic segmentation of sublingual images and color quantification of sublingual vein are of great significance to disease diagnosis in traditional Chinese medicine. With the development of computer vision, automatic sublingual image processing provides a noninvasive way to observe patients' tongue and is convenient for both doctors and patients. However, current sublingual image segmentation methods are not accurate enough. Besides, the differences in subjective judgments by different doctors bring more difficulties in color analysis of sublingual veins. In this paper, we propose a method of sublingual image segmentation based on a modified UNet++ network to improve the segmentation accuracy, a color classification approach based on triplet network, and a color quantization method of sublingual vein based on linear discriminant analysis to provide intuitive one-dimensional results. Our methods achieve 88.2% mean intersection over union (mIoU) and 94.1% pixel accuracy on tongue dorsum segmentation, and achieves 69.8% mIoU and 82.7% pixel accuracy on sublingual vein segmentation. Compared with the state-of-art methods, the segmentation mIoUs are improved by 5.8% and 5.3% respectively. Our sublingual vein color classification method has the highest overall accuracy of 81.2% and the highest recall for the minority class of 77.5%, and the accuracy of color quantization is 90.5%.Clinical Relevance- The methods provide accurate and quantified information of the sublingual image, which can assist doctors in diagnosis.

Detection of Abnormal Changes on the Dorsal Tongue Surface Using Deep Learning.

Background and Objective: The tongue mucosa often changes due to various local and systemic diseases or conditions. This study aimed to investigate whether deep learning can help detect abnormal regions on the dorsal tongue surface in patients and healthy adults. Materials and Methods: The study collected 175 clinical photographic images of the dorsal tongue surface, which were divided into 7782 cropped images classified into normal, abnormal, and non-tongue regions and trained using the VGG16 deep learning model. The 80 photographic images of the entire dorsal tongue surface were used for the segmentation of abnormal regions using point mapping segmentation. Results: The F1-scores of the abnormal and normal classes were 0.960 (precision: 0.935, recall: 0.986) and 0.968 (precision: 0.987, recall: 0.950), respectively, in the prediction of the VGG16 model. As a result of evaluation using point mapping segmentation, the average F1-scores were 0.727 (precision: 0.717, recall: 0.737) and 0.645 (precision: 0.650, recall: 0.641), the average intersection of union was 0.695 and 0.590, and the average precision was 0.940 and 0.890, respectively, for abnormal and normal classes. Conclusions: The deep learning algorithm used in this study can accurately determine abnormal areas on the dorsal tongue surface, which can assist in diagnosing specific diseases or conditions of the tongue mucosa.

Early interceptive treatment of a skeletal open bite using a vertical holding appliance in combination with myofunctional therapy, and a smile-clenching-swallow exercise: a case report with a 3-year follow-up

Abstract This case report aimed to describe the effectiveness of myofunctional therapy involving a vertical holding appliance and a smile–clenching–swallow exercise for vertical control, in a growing patient who presented with a high-angle facial pattern. A 10-year-old girl sought treatment for a skeletal open bite. Early interception aimed to reduce the divergent skeletal growth pattern. The patient was asked to perform a smile–clenching–swallow exercise by pushing the tongue dorsum against a palatal resin pad on a transpalatal arch. The action exerted an upward force on the maxillary first molars, which reinforced the effects of myofunctional therapy. This interaction between the tongue and resin pad resulted in positive feedback, and a constant intrusive force delivered to the molars and balanced co-operation from the orofacial musculature. The initial vertical skeletal discrepancy was successfully resolved within 3 months. The subsequent fixed appliance treatment was straightforward. After 3 years of follow-up, the treatment outcome was stable.

Site-specialization of human oral Gemella species

ABSTRACT Gemella species are core members of the human oral microbiome in healthy subjects and are regarded as commensals, although they can cause opportunistic infections. Our objective was to evaluate the site-specialization of Gemella species among various habitats within the mouth by combining pangenomics and metagenomics. With pangenomics, we identified genome relationships and categorized genes as core and accessory to each species. With metagenomics, we identified the primary oral habitat of individual genomes. Our results establish that the genomes of three species, G. haemolysans, G. sanguinis and G. morbillorum, are abundant and prevalent in human mouths at different oral sites: G. haemolysans on buccal mucosa and keratinized gingiva; G. sanguinis on tongue dorsum, throat, and tonsils; and G. morbillorum in dental plaque. The gene-level basis of site-specificity was investigated by identifying genes that were core to Gemella genomes at a specific oral site but absent from other Gemella genomes. The riboflavin biosynthesis pathway was present in G. haemolysans genomes associated with buccal mucosa but absent from the rest of the genomes. Overall, metapangenomics show that Gemella species have clear ecological preferences in the oral cavity of healthy humans and provides an approach to identifying gene-level drivers of site specificity.

Tongue Flap for Closure of Complex Oronasal Fistula.

Complex oronasal fistula is one of the most frequent secondary complications of cleft palate correction and is considered a reconstructive challenge. Tongue flaps are one of the procedures for the treatment of complex fistulas associated or not with multiple previous procedures, offering a high success rate, few complications, and problems during its development. This study evaluates the efficacy in terms of functionality, esthetic, donor area morbidity and clarifies surgical technique steps. Descriptive cohort study was performed between August 2011 to August 2021 where an anteriorly based dorsal tongue flap was performed in 30 patients with complex palatal fistulas, evaluating outcomes in terms of technique reproducibility and flap viability, correction of oronasal regurgitation, speech, donor site morbidity, complications, and esthetics. The senior author has used this technique with consistent clinical outcomes to improve complex oronasal fistula with minimal complications, with a good success rate in terms of correction of the palatal defect with imperceptible alteration of the lingual donor area. In addition, establishes a specific definition of persistence and recurrence of oronasal fistula. The tongue flap is considered the gold standard in complex oronasal fistula reconstructions with satisfactory outcomes, and it offers an adequate amount of vascularized tissue achieving fistula closure without functional or esthetic impairment of the donor area and is a highly reproducible technique.

Lip and tongue pressure and the functionality of oro-facial structures in healthy individuals.

With the ageing process changes in the musculature of oro-facial structures take place, consequently there is a reduction in the strength and mobility of the lips, tongue and cheeks. The aim of this study was to correlate oro-facial structures and chewing and swallowing functions among a group of senior citizens and young adults and check the influence of lip and tongue pressure of these functions. This is an observational, cross-sectional and analytical study. Thirty seniors with an average age of 67.13 years and 30 young adults with an average age of 22.03 years participated in the study. The Oro-facial Myofunctional Assessment Protocol with Scores for the Elderly and the Oro-facial Myofunctional Assessment Protocol with Expanded Scores were also used. The evaluation of the force of pressure of the lips and tip and dorsum of the tongue was carried out using the Biofeedback device Pró-Fono: Lip and Tongue Pressure. Young adults had a higher evaluation score for the aspect/posture of the face, cheeks, lips, mentalis muscle, tongue, mobility of lips, tongue, jaw and cheeks, chewing and swallowing functions, total time and chewing strokes, and tip pressure and dorsum of tongue. According to the Structural Equation Modelling, a direct relationship was found between the tongue dorsum pressure force and the swallowing function. With healthy ageing changes occurring in the appearance, posture and mobility of the lips, tongue, jaw and cheeks, with the seniors and reduced performance of chewing and swallowing functions.

CHRONIC HYPERPLASTIC CANDIDIASIS AS A RARE ADVERSE EVENT OF SECUKINUMAB THERAPY

Secukinumab is an anti-IL-17A monoclonal antibody used for the treatment of psoriasis, a frequent chronic inflammatory skin disease. However, IL-17 is essential in immunity against oral opportunistic fungal pathogens; therefore, oral candidiasis can occur in patients treated with this drug, although adverse oral events are not widely described. A 72-year-old male patient with arthritis psoriasis managed with Secukinumab 300 mg once a month, for 90 days, presented a burning white plaque on the mid dorsal posterior tongue. Fungal culture was performed and a diagnosis of oral candidiasis was established. Systemic and topical antifungal medication led to regression of the lesion and burning sensation resolution. No symptoms or recurrence of the lesion were observed after six months of follow up. This case highlighted the importance of monitoring patients who are under treatment with IL-17 blockers due to the risk of opportunistic infections. Secukinumab is an anti-IL-17A monoclonal antibody used for the treatment of psoriasis, a frequent chronic inflammatory skin disease. However, IL-17 is essential in immunity against oral opportunistic fungal pathogens; therefore, oral candidiasis can occur in patients treated with this drug, although adverse oral events are not widely described. A 72-year-old male patient with arthritis psoriasis managed with Secukinumab 300 mg once a month, for 90 days, presented a burning white plaque on the mid dorsal posterior tongue. Fungal culture was performed and a diagnosis of oral candidiasis was established. Systemic and topical antifungal medication led to regression of the lesion and burning sensation resolution. No symptoms or recurrence of the lesion were observed after six months of follow up. This case highlighted the importance of monitoring patients who are under treatment with IL-17 blockers due to the risk of opportunistic infections.

Efficacy of concurrent chemoradiotherapy with retrograde super selective intra-arterial infusion combined with cetuximab for synchronous multifocal oral squamous cell carcinomas

BackgroundThe incidence of multicentric oral cancer is increasing. However, treatment encounters difficulty if each tumor needs to be treated simultaneously. The objective of this clinical case report is to highlight the effect of concurrent chemoradiotherapy with retrograde superselective intra-arterial infusion combined with systemic administration of cetuximab on synchronous multifocal oral squamous cell carcinomas.Case presentationA 70-year-old man presented to the hospital with multiple tumors and oral pain. Three independent tumors were found in the right dorsal tongue, left edge of the tongue, and left lower lip. Based on the characteristic appearance of the lesions and further evaluation, clinical diagnoses of right tongue cancer “T3”, left tongue cancer “T2” and lower left lip cancer “T1”, N2cM0 were made. Treatment was initiated with systemic administration of cetuximab, followed by intra-arterial chemoradiotherapy. Treatment results were complete response on all three local lesions, and left neck dissection was performed following the initial treatment. The patient showed no evidence of recurrence during the 4 years follow-up period.ConclusionsThis novel combination treatment seems to be a promising strategy for patients with synchronous multifocal oral squamous cell carcinoma.

Surgical Treatment of the Cranial Basis Teratoma in a Newborn and Palatal Reconstruction With Tongue Flap a 17-Years Follow-Up: A Case Report

Epignathus or Tessier fissure 0-14 is a rare teratoma composed of the three embryonic germ layers. Clinically, it appears as a mass covered with skin and mucosa, originating from pluripotential stem cells. According to the latest classification by the World Health Organization teratoma represents the main benign Germ cell tumors of the sinus region and presents similar histological aspects with its counterparts in the gonads and other extragonadal sites. The purpose of this study is to present a case of epignathus originating from the base of the skull in a Caucasian female patient with a cleft palate after the incisive foramen, not affecting the nasal floor. During physical examination, via intraoral route, in the region below the base of the skull, an extensive solid mass, covered by mucosa and with the presence of hair. Computed tomography confirmed the lesion, in the region corresponding to the base of the patient’s skull. The first surgical approach of resection occurred at the 40th day of the patient’s life, under general anesthesia and subsequent primary closure of the palatal defect. The second surgery was performed 10 months later, when tissue expanders were used on the palate to increase the mucosal surface. At the age of 5, the patient underwent surgery with a tongue flap, from the lingual dorsum, with an anterior pedicle. The patient was kept under sedation and relaxation for a period of 10 days for flap autonomy. After this period, the section of the flap and the reconstruction of the tongue dorsum were performed. The patient had a good evolution and was maintained under outpatient treatment. Pediatricians and pediatric dentists should be aware of the importance of prenatal exams and soon after birth, to identify possible deformities in neonatal patients, which favors the diagnosis. The 17-year postoperative follow-up of complete surgical removal of the teratoma and reconstruction of the cleft palate, combining the use of a tissue expander on the palate and a flap on the dorsum of the tongue, proved to be a viable resource for improving the patient’s quality of life.

COMPREHENSIVE MANAGEMENT OF ORAL FRAILTY IN MULTIPLE SYSTEMIC DISEASES GERIATRIC PATIENT

ABSTRACTBackground Oral frailty is an important geriatric syndrome characterized by decreases in oral function that coincides with declines in cognitive and physical function. Objective: The aim of this case report is to describe the comprehensive management of oral frailty in a medically compromised geriatric patient prior to cardiovascular surgery. Case: A 64-year-old male patient complained of pain in swallowing and sore mouth since two days before. He had multiple systemic diseases, including infective endocarditis, acute kidney injury, type II diabetes mellitus, thrombocytopenia, and electrolyte-fluid imbalance. Extra-oral examination showed lymphadenitis, icteric sclera, and dry-exfoliative lips. Intra-oral examination revealed tongue depapillation, frothy saliva, and dry mucosa with poor oral hygiene. The scraped-off white plaque leaving erythematous area was found on the dorsal and ventral tongue, buccal mucosa, and hard palate. Irregular multiple major ulcers, surrounded by erythema, well-demarcated with yellowish concave base, and covered by thick yellowish-green sputum at the soft palate to the uvula. The diagnosis was exfoliative cheilitis, aphthous-like ulcer, acute pseudomembranous candidiasis, and moderate xerostomia. A D-E-N-T-A-L questionnaire was used to evaluate oral frailty, and the cumulative result was seven. Case Management: The patient was treated with 100% petroleum jelly, 0.12% chlorhexidine digluconate mouthwash, and chlorine dioxide-zinc mouthwash three times a day. The oral lesions showed significant improvement after one week of treatment. Conclusion: Appropriate therapy for oral lesions and eliminating the infection could be considered to minimize the long-term effect of oral frailty. The comprehensive management of oral frailty could be beneficial for improving the quality of life. Keywords: Geriatric, Oral frailty, Oral lesion, Systemic disease

Gestural characterisation of vowel length contrasts in Australian English

Many languages contrast long and short vowels, but the phonetic implementation of vowel length contrasts is not fully understood. We examine articulation of long and short vowels in Australian English to investigate whether duration contrasts involve intrinsic differences in the underlying gestures, or differences in their timing relationships with flanking consonants. We used electromagnetic articulography to track tongue dorsum and lip movement in two long-short vowel pairs /iː-ɪ/ (bead – bid) and /ɐː-ɐ/ (bard – bud) produced in /pVp/ syllables by nine speakers of Australian English. For short vowels, lingual movement towards the vowel target (formation interval) is shorter and smaller, but not stiffer, than that of long vowels. Syllables containing the short vowel /ɐ/ also exhibited more vowel-coda overlap than those containing /ɐː/. These data suggest that both vowel-intrinsic and syllable-level mechanisms are involved in the realisation of vowel length contrasts in Australian English.

Comparative Study of Lingual Papillae, Lingual Glands and Lyssa of the Tongue of Selected Wild Felids (Carnivora, Felidae) in Biological Aspects.

Although much attention has been paid in the literature to the morphology of the tongue in various animal species, including some Felidae, it has not yet been described in detail in the vulnerable Neofelis nebulosa and Panthera leo bleyenberghi and the last concern Lynx lynx and Otocolobus manul. Therefore, the present study aimed to characterize the features of the tongue surface, lingual glands and lyssa in the above-mentioned four selected wild species of the Pantherinae and Felinae subfamilies. Macroscopic, histological, histochemical and ultrastructural analyzes were used in the present work. Comparative analyzes of the dorsal tongue surface showed the presence of mechanical lingual papillae on five subtypes of filiform papillae on the apex and body and conical papillae on the root of the tongue. Gustatory papillae in the four analyzed species were fungiform papillae and various numbers of vallate papillae. Foliate papillae were absent in P. leo bleyenberghi and L. lynx, while delicate smooth folds, which were separated by parallel grooves but without taste buds, were present in N. nebulosa. The vallate and foliate papillae were accompanied by lingual glands, which produced a serous secretion, whereas the mixed lingual glands of the lingual root were with a predominance of mucus secretions comparable to four captive Felidae species. In the median plane on the ventral surface of the apex under its epithelium and within the muscle fibers, the lyssa was also observed to a varying degree, with the least developed, and thought about the size of the entire tongue, was in P. leo bleyenberghi. The lyssa structure in the four species was dominated by adipose tissue. The obtained results contribute knowledge concerning the functional anatomy of the tongue in four selected Felidae species, especially in terms of comparative anatomy.

An Ultrasound Investigation of Tongue Dorsum Raising in Children with Cleft Palate +/- Cleft Lip.

This study aimed to determine whether increased raising of the back of the tongue is evident in children with repaired cleft palate with or without cleft lip (CP+/-CL). We hypothesized that children with CP+/-CL would show increased raising of the tongue dorsum, a compensatory pattern. Secondary data analysis of mid-sagittal ultrasound tongue imaging data from 31 children with CP+/-CL and 29 typically developing children were used. We annotated the consonants /ʃ, t, s, k/ at the point of maximum constriction in an /aCa/ environment. Children with CP+/-CL said the tokens 10 times, typically developing children said them once. We automatically fitted splines to the tongue contour and extracted the Dorsum Excursion Index (DEI) for each consonant. This metric measures the relative use of the tongue dorsum, with more posterior consonants having higher values. We compared DEI values across groups and consonants using a linear mixed effects model. DEI was predicted by the interaction of consonant (baseline: /ʃ/) and speaker type (baseline: TD), including by-speaker random slopes for consonant and random intercepts for speaker. Overall DEI was not higher in children with CP+/-CL compared to typically developing children. Between groups the only significant difference was the position of /k/ relative to /ʃ/, where the difference between these two consonants was smaller in the children with CP+/-CL. There was no support for the hypothesis that increased raising of the tongue dorsum is a common characteristic in children with repaired CP+/-CL. However, individual children may present with this pattern.

An ulcerative nodule on the dorsal tongue in an 8-year-old boy

An otherwise healthy 8-year-old boy was consulted in July 2020 presenting with a 20-day history of a painless growth on the tongue which had been associated with trauma. According to his parents, the lesion initially appeared as a “blood-filled blister” and had evolved into an ulcerated swelling. Intraoral examination revealed a reddish, sessile nodule with an ulcerated surface, located in the midline of the tongue dorsum (Figure 1A-B). Although the lesion was asymptomatic, the patient reported slight discomfort when swallowing. The patient's past medical and family histories were unremarkable and non-contributory to any systemic conditions or malignancy. Given the history of trauma, location, and clinical appearance, the main differential diagnoses were reactive lesions or benign mesenchymal tumors. An incisional biopsy was performed under local anesthesia to elucidate the diagnosis, and 3 weeks after the procedure, the lesion presented an accelerated growth, doubling its initial size, now appearing as an aggressive dome-shaped nodule. (Figure 1C-D).

Limits on gestural reorganization following vowel deletion: The case of Tokyo Japanese

The coordination of gestures in consonant clusters differs across languages and hence must be a learned aspect of linguistic knowledge. Precisely pinning down the coordination relation used in a particular language, or for a particular consonant cluster type, has been facilitated by recent research showing that coordination relations structure kinematic variation in unique ways. We apply these methods to a hitherto under-explored topic, the coordination of consonant clusters created via vowel deletion. Our case study involves fricative-fricative and fricative-stop consonant clusters resulting from the variable deletion of devoiced vowels in Tokyo Japanese. Examination of articulatory data obtained by Electromagnetic Articulography (EMA) show that some consonant clusters, i.e., fricative-stop clusters, show gestural reorganization whereas other cluster types, i.e., fricative-fricative sequences, behave as if a vowel remains in place, despite the fact that the tongue dorsum movement for the vowel is absent from the articulatory record. We discuss several theoretical possibilities to account for the differential effects of vowel deletion on gestural re-organization in these environments.

Site Specialization of Human Oral Veillonella Species.

Veillonella species are abundant members of the human oral microbiome with multiple interspecies commensal relationships. Examining the distribution patterns of Veillonella species across the oral cavity is fundamental to understanding their oral ecology. In this study, we used a combination of pangenomic analysis and oral metagenomic information to clarify Veillonella taxonomy and to test the site specialist hypothesis for the Veillonella genus, which contends that most oral bacterial species are adapted to live at specific oral sites. Using isolate genome sequences combined with shotgun metagenomic sequence data, we showed that Veillonella species have clear, differential site specificity: Veillonella parvula showed strong preference for supra- and subgingival plaque, while closely related V. dispar, as well as more distantly related V. atypica, preferred the tongue dorsum, tonsils, throat, and hard palate. In addition, the provisionally named Veillonella sp. Human Microbial Taxon 780 showed strong site specificity for keratinized gingiva. Using comparative genomic analysis, we identified genes associated with thiamine biosynthesis and the reductive pentose phosphate cycle that may enable Veillonella species to occupy their respective habitats. IMPORTANCE Understanding the microbial ecology of the mouth is fundamental for understanding human physiology. In this study, metapangenomics demonstrated that different Veillonella species have clear ecological preferences in the oral cavity of healthy humans, validating the site specialist hypothesis. Furthermore, the gene pool of different Veillonella species was found to be reflective of their ecology, illuminating the potential role of vitamins and carbohydrates in determining Veillonella distribution patterns and interspecies interactions.