Ashley Wong
Faculty Mentors: Robert Cornell
Department: Oral Health Sciences
Supported By: NIH Grant 5R01DE023575
Title: Investigating the missing heritability for Van de Woude syndrome and non-syndromic orofacial cleft
Objectives: Non-syndromic cleft lip and palate (CL/P) refers to congenital deformities of the lip and/or palate that occur without associated syndromic conditions. Genetic factors and environmental factors primarily influence these conditions. Several genes have been implicated in non- syndromic CL/P, including those involved in craniofacial development and cellular signaling pathways. To identify candidates for the genes that when mutated cause orofacial cleft, we sought to determine the members of the regulatory cascade connecting the kinase PRKCI and the transcription factor IRF6, both encoded by Van der Woude risk genes. By elucidating the specific genes regulating orofacial cleft, it allows researchers to explore targeted kinase medications, like folic acid, to reduce the incidence of such birth defects.
Methods: We employed rescue experiments in zebrafish embryos to elucidate the regulatory relationships among PRKCI, IKK1, RIPK4, and IRF6 in periderm differentiation. The embryonic enveloping layer (EVL), analogous to mammalian periderm, was used as a functional readout. Loss-of-function was induced using a PRKCI inhibitor, and rupture during epiboly was assessed. Rescue was evaluated by expressing activated forms of ikk1, ripk4, or irf6. We further compared phenotypes in ikk1 loss-of-function mutant embryos and the ability of activated IRF6 to prevent rupture.
Results: Phosphomimetic IRF6 and constitutively active RIPK4 rescued rupture in aPKC-inhibited embryos, whereas activated RIPK4 failed to rescue ikk1 mutants. Western blots showed a single band for kinase-dead RIPK4 regardless of PRKCI activity, indicating that PRKCI does not phosphorylate RIPK4 in a manner producing a detectable mobility shift.
Conclusions: Our findings support a regulatory cascade in which PRKCI signals through IKK1 and RIPK4 to activate IRF6 during periderm differentiation. Future work will refine the specific relationship between IKK1 and RIPK4 and further illuminate mechanisms underlying Van der Woude syndrome.
Tenzin Namgyal
Faculty Mentors: Susan Coldwell, Cameron Randall
Department: Oral Health Sciences
Supported By: SURF
Title: Feasibility of Taste and Smell Screening During Routine Dental Visits
Objectives: The prevalence of taste and/or smell dysfunction increases with age and may be an early indicator of neurodegenerative disease, yet these senses are rarely assessed in healthcare. Healthy People 2030 has set a national goal of increasing the proportion of adults with taste and smell dysfunction who discuss the problem with a provider. The aim of this study was to assess the feasibility of implementing taste and smell screening during routine dental visits.
Methods: Ten dentists who worked at least one day/week in private practice were recruited to participate in individual qualitative interviews. The semi-structured interview guide queried the frequency that patients bring up taste and smell concerns, how they respond to these concerns, and what they see as barriers to implementing taste and smell screening during routine dental examinations. As part of the interview, three brief screening tools (The 4-Item Pocket Smell Test®, Scentinel®, and a three-drop taste test) were demonstrated. Transcripts were produced using Rev and verified for accuracy by comparison with audio files. Two investigators independently coded the transcripts using an inductive content analysis.
Results: Dentists reported that, since the COVID-19 pandemic has ended, patients rarely if ever bring up taste and smell concerns. When concerns are brought up, the issue is most often a complaint about a bad taste or odor, rather than a reduction in ability to taste or smell. Dentists responded positively to the brief screening tests and identified ways to incorporate these tests into the appointment workflow. However, they also identified significant barriers to implementing testing that included lack of knowledge regarding how to address taste and smell problems, lack of reimbursement for testing, time constraints, and difficulty in making referrals.
Conclusions: Dentists are reluctant to implement screening for taste and smell concerns without addressing gaps in knowledge, referral systems, and reimbursement.
Jane Soper
Faculty Mentors: Dr. Donald Chi, Dr. Gulaiim Almatkyzy
Department: Oral Health Sciences
Supported By: The study was funded by the U.S. National Institute of Dental and Craniofacial Research (NIDCR) (Grant Nos. U01DE027629 and T90DE021984) and the University of Washington Dr. Douglass L. Morell Dentistry Research Fund.
Title: Differential sugar-sweetened beverage intake among Alaska Native boys and girls: a mixed-methods study
Objectives: To examine the association between children’s sex and sugar-sweetened beverage (SSB) intake among Alaska Native children and explore caregiver perceptions of differential SSB intake among boys and girls.
Methods: This mixed-methods study was conducted among participants enrolled in a prospective SSB reduction trial in three Yup’ik Alaska Native communities. Children’s SSB intake was estimated from hair samples using a carbon-nitrogen stable isotope ratio. Mixed-effects linear regression assessed associations between SSB intake and children’s sex. Qualitative interviews were conducted with caregivers of children and analyzed inductively using thematic analysis.
Results: The quantitative study included 201 children. The mean age of children was 6.1 years, 44.3% were girls, and 41% lived in households with an annual income below $10,000. Mean daily SSB intake was 3.2 servings/day for boys and 2.9 servings/day for girls. In the adjusted model, boys consumed 0.4 more SSB servings/day than girls (95% CI: 0.23, 0.65, p < 0.001). The qualitative study included 22 caregivers. Ten caregivers perceived that sons consumed more SSB, seven perceived that daughters consumed more SSB, and five perceived no sex difference. Higher SSB intake among sons was commonly attributed to greater stubbornness, higher physical activity, and increased autonomy in beverage choice. In contrast, higher intake among daughters was linked to daughters’ stronger preferences for sweet beverages, greater autonomy due to being older siblings, and household rules that limited sons’ intake more than daughters.
Conclusions: Alaska Native boys consumed more SSB than girls, supported by biomarker data. Caregiver interviews identified perceived behavioral and contextual factors that may explain this pattern. Additional research is needed to understand sex-based differences in risk factors for tooth decay among Alaska Native children.
Shirley Jwa
Faculty Mentors: Dr. Robert Cornell
Department: Oral Health Sciences
Supported By: Dr. Douglass L. Morell Dentistry Research Fund
Title: Functional Analysis of a Non-Coding OFC-Associated Variant at the TP63 Locus Using Luciferase Reporter Assays and CRISPR Editing
Objectives: Genome-wide association studies have identified non-coding variants near TP63 as risk factors for orofacial clefts (OFCs), yet the functional mechanisms underlying these associations remain unclear. This study aimed to functionally characterize the OFC-associated single-nucleotide polymorphism rs75436877 by assessing its regulatory activity and its effect on endogenous TP63 expression in epithelial cells.
Methods: Baseline TP63 expression was quantified by RT-qPCR in multiple epithelial cell lines to identify an appropriate experimental model. Genomic fragments containing either the risk or non-risk allele of rs75436877 was cloned into a luciferase reporter vector and tested for enhancer activity in telomerase-immortalized gingival keratinocytes (TIGKs). Dual-luciferase assays were performed in two independent experiments with triplicate wells per condition. To assess endogenous effects, CRISPR ribonucleoprotein complexes targeting rs75436877 were electroporated into TIGKs with a single-stranded donor template. Editing outcomes were evaluated by Sanger sequencing, and TP63 expression was measured by RT-qPCR.
Results: TIGKs exhibited the highest baseline TP63 expression among the cell lines tested and were selected for downstream experiments. Luciferase reporter assays demonstrated that the risk allele of rs75436877 consistently conferred higher enhancer activity than the non-risk allele across independent experiments, although both alleles exhibited relatively weak activity compared to the promoter control. CRISPR targeting resulted in efficient on-target cleavage with heterogeneous indel formation, but no evidence of precise homology-directed repair was detected. Bulk RT-qPCR analysis revealed no measurable change in TP63 expression following genome editing.
Conclusions: These findings indicate that rs75436877 exhibits allele-dependent regulatory activity in reporter assays but does not produce a detectable change in endogenous TP63 expression following bulk CRISPR perturbation. This work highlights the challenges inherent in functionally validating weak enhancers and emphasizes the need for precise genome editing approaches to fully elucidate the transcriptional consequences of non-coding risk variants.
Alexander Le
Faculty Mentors: Dr. Susan Coldwell, Dr. Mark Drangsholt
Department: Oral Medicine
Supported By: Dr. Douglass L. Morell Dentistry Research Fund
Title: Clinical Evaluation of Microsoft Copilot in Taste Disorder Diagnosis
Objectives: To evaluate whether a HIPAA-compliant large language model Microsoft Copilot can support differential diagnosis and clinical reasoning in taste disorders by comparison with expert clinician assessments.
Methods: Six de-identified taste disorder cases were analyzed by Microsoft Copilot and two experienced oral medicine clinicians using standardized clinical summaries. AI-generated differentials, diagnostic test recommendations, and management considerations were compared with clinician assessments. Agreement was evaluated using Top-1/Top-2 concordance, Cohen’s kappa, and nonparametric comparisons of diagnostic breadth.
Results: Copilot demonstrated diagnostic agreement in 83.3% of cases. Inter-rater agreement between Copilot and clinicians was comparable to expert–expert agreement, with highest concordance for well-defined etiologies. Copilot generated broader differential diagnoses than clinicians and showed strong agreement with clinician diagnostic testing recommendations for core evaluations.
Conclusions: AI-assisted clinical reasoning showed agreement with clinician assessments comparable to inter-clinician variability, supporting the feasibility of using large language models as decision-support tools for taste disorder evaluation.
Megha Rao
Faculty Mentors: Dr. Lindsay Yap
Department: Endodontics
Supported By: Dr. Douglass L. Morell Dentistry Research Fund
Title: Comparative Evaluation of Biomimetic, Tactile and Visual properties of Endodontic Simulation Teeth Vs Natural teeth
Objectives: This study compares the tactile and visual properties of two commercially available endodontic simulation teeth, Frasaco Premium Endo #3 and Acadental X-2 Endo #3, with natural extracted teeth during access cavity preparation.
Methods: Twenty-four participants, including dental students and endodontic specialists, performed standardized access preparations on one natural maxillary molar and two simulation teeth. Procedure times were recorded, and participants completed a structured questionnaire assessing tactile realism, anatomical accuracy, and visual similarity. Statistical analyses included Wilcoxon signed-rank, paired t-tests, and Kruskal–Wallis tests.
Results: Mean access times were similar for Frasaco (7.28 min) and X-2 Endo (7.12 min), with no significant differences (p > 0.48). Survey responses indicated moderate realism for both models, with Frasaco rated higher for ease of cutting but criticized for excessive softness and idealized anatomy. X-2 Endo was perceived as closer to natural hardness but overly resistant, causing bur wear and ergonomic challenges. Neither model fully replicated natural tactile feedback or anatomical variability.
Conclusions: Current endodontic simulation teeth provide valuable logistical and educational benefits but fall short of replicating the tactile and anatomical complexity of natural dentition. Frasaco and X-2 Endo models each offer distinct advantages such as ease of cutting and predictable anatomy versus greater hardness and durability, but neither fully meets the requirements for comprehensive skill development. To optimize training, a progressive approach that combines different simulation models with natural teeth is recommended. Future innovations should prioritize material engineering and anatomical similarities to create hybrid composition models that deliver realistic tactile feedback, accurate internal morphology, and consistent quality. Such advancements will strengthen simulation-based education and better prepare students for clinical practice.
Zhiyuan Yang
Faculty Mentors: Dr. Fritzie Arce-McShane
Department: Oral Health Sciences
Supported By: Dr. Douglass L. Morell Dentistry Research Fund, R01 AG069227, P51 OD010425, U42 OD011123
Title: Neuromechanics of Temporomandibular Joint During Mastication
Objectives: To examine how food texture (soft vs. chewy) affects temporomandibular joint (TMJ)
neuromechanics and how these kinematic patterns relate to age-associated changes in jaw morphology.
Methods: Four male rhesus macaques (ages 7, 8, 19, and 21 years) were implanted with radiopaque tantalum beads for 3D mandibular tracking. Animals chewed grapes and gummy bears while jaw motion was captured using biplanar X-ray videography and reconstructed via X-ray Reconstruction of Moving Morphology (XROMM). Gape cycles were classified as Stage 1/Stage 2 Transport (S1T/S2T), Manipulation, Chewing (Left/Right), or Swallowing (Intercalated/Terminal). Translational and rotational components were quantified from anterior mandible (AM) and posterior TMJ markers. Concurrently, neuronal activity was recorded using Utah microelectrode arrays placed in orofacial regions of the primary motor (M1) and somatosensory (SC) cortices under control and nerve-block conditions. Signals were filtered and spike-sorted to isolate single-unit activity. Subjects were grouped as Young or Old. One-way ANOVA identified group-level effects, followed by Welch’s t-tests for pairwise comparisons. Mandibular morphology was assessed from cone-beam CT (CBCT) scans registered to posterior landmarks, aligned via Generalized Procrustes Analysis (GPA), and evaluated with principal component analysis (PCA) and point-cloud mapping.
Results: During early chewing (S1T), both TMJ (rotational) and AM (translational) movements were grape-dominant, with no significant age effect emerging during rhythmic chewing. Later phases (Chew R, S2T, and Swallow Intercalated) showed a shift toward gummy-bear dominance. Preliminary M1 and SC data suggest modulation of firing rates by food texture; further analysis is needed to confirm the influence of aging. PCA revealed greater morphological variability in older animals, concentrated at the coronoid process and condylar head.
Conclusions: Food texture influences sequential food transport with kinematic jaw movements, indicating adaptive coordination for bolus adjustment. Despite texture-dependent variation, rhythmic chewing remained stable—implying compensatory tongue control. Increased structural variability in older jaw morphology suggests age-related remodeling and reduced functional stability.
Priyanka Prajapati
Faculty Mentors: Dr. Ana Lucia Seminario
Department: Derouen Center for Global Health
Supported By: Dr. Douglass L. Morell Dentistry Research Fund
Title:Bridging HIV Care’s Oral Health Gaps: Training Kisumu’s Non-Dental Providers
Objectives: With Kenya’s national dentist-to-population ratio at approximately 0.27 per 10,000 and lower provider availability in rural regions, many oral health needs among people living with HIV (PLHIV) often remain unmet. This study aimed to address this gap by strengthening oral health integration into HIV care through training non-dental healthcare providers in Kisumu County to perform oral examinations and identify HIV-related oral manifestations.
Methods: With Kenya’s national dentist-to-population ratio at approximately 0.27 per 10,000 and lower provider availability in rural regions, many oral health needs among people living with HIV (PLHIV) often remain unmet. This study aimed to address this gap by strengthening oral health integration into HIV care through training non-dental healthcare providers in Kisumu County to perform oral examinations and identify HIV-related oral manifestations.
Results: With Kenya’s national dentist-to-population ratio at approximately 0.27 per 10,000 and lower provider availability in rural regions, many oral health needs among people living with HIV (PLHIV) often remain unmet. This study aimed to address this gap by strengthening oral health integration into HIV care through training non-dental healthcare providers in Kisumu County to perform oral examinations and identify HIV-related oral manifestations.
Conclusions: Non-dental HIV providers in Kisumu, Kenya increased competence and confidence in providing basic oral health clinical assessments. These findings highlight the importance of expanding oral health training and resources, especially in regions with limited access to dental care through interdisciplinary collaboration for long-term sustainability and better health for PLHIV.
Ziying Tang (Gloria)
Faculty Mentors: Dr. Jeffrey McLean
Department: Department of Periodontics
Supported By: The Jon B. Suzuki Research Award – Omicron Kappa Upsilon (OKU), Dental Alumni Endowed Faculty Award, Dr. Douglass L. Morell Dentistry Research Fund
Title: Oral Health Behaviors and Dental Caries in Prader–Willi Syndrome
Objectives: Prader–Willi Syndrome (PWS) is a complex neurodevelopmental genetic disorder caused by the absence of paternally expressed genes on chromosome 15q11-q13. Individuals with PWS often present with cognitive impairments, hypothalamic dysfunction, and various systemic abnormalities, including reduced salivary flow and lower salivary pH compared to age-matched controls. This study examined oral health behaviors and the prevalence of dental caries in children and adolescents with PWS.
Methods: This is a cross-sectional study of participants aged 5–21 years with a confirmed diagnosis of PWS recruited from the PWS Clinic at Seattle Children’s Hospital. Each participant underwent a clinical examination assessing dental caries, oral disorders, and plaque index, completed an oral health behavior survey, and had intraoral salivary pH measured using pH strips. Medical history was retrieved. Given the small sample size, descriptive statistics were used to summarize the data.
Results: Twenty-one individuals (mean age 11.7 years, SD 4.4) participated in this study. Eight participants (38.1%) were caries-active/experienced. For the entire sample, the median DMFS was 0.0 (IQR 0.0-3.5) and dmfs was 0.0 (IQR 0.0-0.0). The overall median intraoral salivary pH was 6.2 (IQR 6.0-6.4), with 6.2 (IQR 6.0-6.4) for the caries-free and 6.2 (IQR 6.1-6.5) for the caries-active/experienced. Mean plaque index was 1.42 (SD 0.83) overall, with 1.15 (SD 0.72) for the caries-free and 1.95 (SD 0.77) for the caries-active/experienced. Eleven participants (52.4%) exhibited attrition, and two (9.5%) showed erosion. Ten participants (47.6%) had current or previous gastroesophageal reflux disease (GERD). Participants with caries reported less frequent toothbrushing and dental visits. All participants had a history of receiving topical fluoride. None of the participants reported dental fear.
Conclusions: In this sample of patients with PWS, poorer oral hygiene practices and less frequent dental visits appeared to be associated with greater caries experience. A high prevalence of GERD and tooth attrition was observed, underscoring the need for targeted preventive strategies and regular dental care in this population.
Sydney Kim
Faculty Mentors: Dr. Hannele Ruohola-Baker
Department: Biochemistry
Supported By: Dentistry SURF Fund, T90 DE021984
Title: Constructing a Mouse scRNA-Seq Atlas of Palatogenesis for Human Comparative Analysis
Objectives: Cleft lip and palate are among the most common congenital anomalies in humans, but the cellular mechanisms governing palatal fusion remain largely unknown due to the rarity of high-quality human embryological samples. To support our lab’s investigation of human embryological palate development using spatial transcriptomics, this study aimed to construct an integrated single-cell RNA-sequencing (scRNA-seq) atlas of mouse palatogenesis as a comparative framework. The goal of this work was to integrate multiple published mouse scRNA-seq datasets before and after palate fusion to create a framework to overlay onto human developmental data and to reveal cellular identities and molecular pathways that characterize and drive human palatogenesis.
Methods: I conducted a systematic search of publicly available scRNA-seq datasets of the craniofacial region of embryonic mouse. Studies were included if they contained samples between embryonic days E9.5-E15.5 and provided raw or processed count matrices. Corresponding datasets were downloaded from the Gene Expression Omnibus using accession numbers provided in the original manuscripts. Raw feature-barcode matrices were imported into Python using Scanpy, reconciled for consistent gene nomenclature and cell-barcode formatting, and filtered to remove low-quality cells. Filtered datasets were integrated using scvi-tools to train a variational autoencoder model (SCVI) that corrected batch effects and generated a unified latent representation. Leiden clustering was performed on the integrated latent space, and marker gene expression was evaluated to assign biological identities to clusters. Epithelial populations were identified using canonical markers and examined across datasets and developmental stages.
Results: Five published mouse scRNA-seq datasets spanning embryonic days E9.5-E15.5 were integrated into a combined atlas using SCVI. UMAP visualization labeled by published dataset demonstrated strong integration among studies, indicating clustering by biological identity rather than dataset origin. When colored by developmental stage, cells mapped largely by chronological stage, confirming successful dataset harmonization and preservation of developmental structure. Known craniofacial lineages, including cranial neural crest-derived mesenchymal, epithelial, endothelial, neuronal, glial, and myogenic populations, were assigned to Leiden clusters using canonical marker genes. Epithelial cells were present at all stages from E9.5 through E15.5, with abundance higher during mid-palatogenesis and lower at later stages, peaking around E13.5.
Conclusions: This study establishes an integrated single-cell RNA-sequencing atlas of mouse palatogenesis spanning the developmental window during which secondary palate formation and fusion occur. The unified representation preserved developmental structure while minimizing batch effects, allowing meaningful comparison of cell populations originating from different experiments. Epithelial cells were successfully identified and shown to be consistently represented across datasets and developmental stages, confirming sufficient epithelial coverage for downstream biological interpretation. This curated mouse epithelial reference provides the foundational dataset needed for comparative mapping to human spatial transcriptomic data and will enable future efforts to identify conserved and divergent epithelial states, reconstruct developmental trajectories, and generate hypotheses about the cellular and molecular events underlying palate fusion.
Nelson Wong
Faculty Mentors: Dr. Jonathan An
Department: Oral Health Science
Supported By: Dentistry SURF Fund, S10 OD032302, KL2 TR002317
Title: Investigating Periodontal Disease in the Dp(16)1Yey Mouse Model of Down Syndrome
Objectives: Periodontal disease is highly prevalent and severe in individuals with Down syndrome (DS), with both immunological and microbiological factors contributing to their increased susceptibility to progressive disease. While there is no single animal model that fully recapitulates the complexity of DS, several well-characterized mouse models enable a mechanistic investigation of specific biological pathways relevant to disease susceptibility and progression. This project will assess whether Dp(16) have accelerated periodontal disease by quantifying bone loss and inflammatory markers in the oral tissues.
Methods: Dp(16)1Yey mice (Dp(16); n=10) and non-carrier controls (n=10) were analyzed for periodontal bone loss and inflammatory marker expression. Alveolar bone loss was quantified using three-dimensional micro–computed tomography (microCT), and inflammatory markers in oral tissues were assessed by quantitative PCR (qPCR) using established inflammatory primers such as TNF-alpha, CXCL-2, and IL-6. Statistical analysis was conducted using two-tailed, unpaired t-tests, where p-values <0.05 were considered statistically significant. Statistical analysis was completed on GraphPad Prism 10.0.
Results: Our molecular and phenotypical data demonstrated that Dp(16) mice exhibit accelerated periodontal disease progression relative to control mice. Pro-inflammatory cytokines and chemokines including TNF-alpha, CXCL2, and IL-6 were significantly upregulated in alveolar bone of DS mice when compared with controls (p<0.05). Additionally, expression of bone turnover markers such as MMP-13, NFATc1, and RANKL was also increased in Dp(16) mice indicating enhanced bone resorption. MicroCT analysis demonstrated a significant increase in alveolar bone loss in Dp(16) mice compared to control mice.
Conclusions: Our data indicate that Dp(16)1Yey mice exhibit accelerated periodontal disease relative to age-matched controls. These findings support the utility of this model for identifying disease-driving pathways and for evaluating targeted interventions to slow or prevent periodontal disease progression.
Sneha Rao
Faculty Mentors: Dr Ivy Lin
Department: Oral surgery
Supported By: Dr. Douglass L. Morell Dentistry Research Fund
Title: Sustainability and waste reduction in academic dental clinics: A multi clinic waste audit at University of Washington School of Dentistry
Objectives: The healthcare sector contributes substantially to greenhouse gas emissions, with dentistry accounting for a notable share. There exists limited data on waste generation within academic dental settings. The purpose of this study was to conduct a comprehensive, multi-clinic waste audit at the University of Washington School of Dentistry (UWSOD) and to identify opportunities for waste reduction and sustainable practices.
Methods: A cross-sectional waste audit was performed across six predoctoral and graduate UWSOD clinics between May and July 2025. Waste generated during one full day of patient care in each clinic was collected, sorted into predefined categories, and weighed. Patient volume was recorded to calculate waste generated per patient. Descriptive statistics were used to summarize waste composition and clinic-level variation.
Results: Preliminary findings suggest that approximately ten studies will be included in the qualitative systematic review. The literature contains measures that are conceptually related to caregiver bandwidth, including caregiver burden, parental self-efficacy, caregiver stress, mental illness, household chaos, and sense of coherence, while highlighting gaps in existing measurement approaches. It is anticipated that current measures fail to capture caregiving capacity as a multidimensional, integrative construct, including the cognitive, psychological, and functional resources caregivers draw upon to support their child’s oral health.
Conclusions: This multi-clinic waste audit establishes baseline data for waste generation in an academic setting and demonstrates a substantial reliance on single-use materials. The study highlights opportunities to reduce waste through improved material selection, glove-use practices, waste segregation, and integration of sustainability principles into dental education and clinical protocols.
Alireza Vahdati
Faculty Mentors: Dr. Ana Lucia Seminario
Department: Timothy A. DeRouen Center for Global Oral Health
Title: Voice-Driven Data Collection in REDCap for Global Oral Health Screenings
Objectives: In many low-and middle-income countries (LMICs), data collection in healthcare remains paper-based. This project explored how artificial intelligence (AI) and voice recognition tools built into smart devices can support electronic data entry into REDCap-a secure data management platform during dental screenings for children under five years old with HIV/AIDS in Kisumu, Kenya. The goal was to introduce and assess a voice-driven data entry workflow to enhance accuracy and efficiency in field-based oral health research.
Methods: Dental screening forms were first created in DOCX and PDF formats, then converted into REDCap-compatible CSV dictionaries for mobile and web deployment. Voice-based data entry was implemented using native smartphone tools: Voice Control on iPhones and Voice Access paired with Gboard on Android devices. These tools enabled hands-free navigation, speech-to-text dictation, and selection of multiple-choice responses. Usability, accuracy, and offline capabilities were compared across platforms. Additionally, external AI tools such as Denti.AI, Overjet, and Bola AI were reviewed for potential integration to support automated odontogram charting.
Results: Voice Control on Apple devices allowed accurate, offline-compatible voice navigation using “Show Numbers” and “Show Grid” overlays within both the REDCap website and mobile app. The REDCap app supported basic data entry and syncing; however, it could not render external modules like the odontogram image map, which remained accessible only via the web interface. Some challenges emerged, including limited recognition of dental terminology and difficulty selecting small interface elements. These issues were partially resolved by simplifying question labels and refining voice commands for improved consistency. Android’s Voice Access, integrated with Gboard, demonstrated comparable functionality, though it requires further evaluation regarding field-level accuracy and offline performance.
Conclusions: Voice-driven REDCap data entry offers a practical, scalable, and cost-effective approach for oral health data collection in resource-limited settings. By enhancing workflow efficiency and reducing transcription errors, this implementation supports broader efforts in global oral health research.
Yung-Hsin Cheng
Faculty Mentors: Dr. Kevin C. Lee, Dr. Jasjit Dillon
Department: Department of Oral and Maxillofacial Surgery
Supported By: Oral and Maxillofacial Surgery Foundation Grant and Osteoscience Foundation Grant
Title: Is body mass index (BMI) associated with fibula free flap skin paddle thickness?
Objectives: The purpose of this study was to measure the association between BMI and fibula skin paddle thickness.
Methods: This is a cross-sectional study of all patients evaluated for fibula free flap (FFF) reconstruction at the University of Washington, Department of Oral and Maxillofacial Surgery from August 2024 to September 2025. Patients with prior lower leg surgery/trauma were excluded. For each patient, data was collected on age, sex, BMI, and primary diagnosis requiring FFF. CT angiograms of the lower extremities were obtained and measurements of skin paddle thickness and lower leg diameter were recorded at a point 60% down the length of the fibula. The primary predictor, BMI, was evaluated as both a continuous and binary categorical variable (<30 vs ≥30 kg/m²). The primary outcome was fibula skin paddle thickness was likewise evaluated as both a continuous and binary variable (<10 vs ≥10mm). Comparisons between study predictors and outcomes were performed with independent sample t-tests and Fisher’s exact tests.
Results: The final sample included 45 subjects. The mean age was 52.3±19.4 years, 62.3% were male, the mean BMI was 26.7±7.6, and 42.2% had a cancer diagnosis. The mean fibula length was 37.3±2.6 cm, the mean skin paddle thickness 6.2±3.0 mm, and the mean posterior intermuscular septum (IMS) length was 12.8±4.0 mm. There were no significant associations between skin paddle thickness and age (r=-0.04; p=0.77) or BMI (r=0.12; p=0.42). There was no significant association between posterior IMS length and skin paddle thickness (r=0.03; p=0.85); however, there was a statistically significant correlation between lower leg circumference and skin paddle thickness (r=0.49; p<0.01). Female sex was associated with greater mean skin paddle thickness (7.5 vs 5.5mm, p=0.04). BMI ≥30 had a larger mean thickness that was not statistically significant (7.9 vs 5.7mm, p=0.06). There were no significant associations between the presence of a thick skin paddle and the predictors of age, BMI, cancer diagnosis, lower leg circumference, and posterior IMS length.
Conclusions: There was no correlation between BMI and fibula skin paddle thickness in our sample. Obese individuals tended to have thicker skin paddles; however, BMI alone was not associated with skin paddle thickness. Because of its variability, the fibula skin paddle should be assessed both clinically and radiographically to obtain the most accurate thickness estimate.
Paridhi Garg
Faculty Mentors: Dr. Lindsey Yap
Department: Endodontics
Title: Clinical Outcomes of Coronal Sealing Strategies After Root Canal Treatment: A Systematic Review of In Vivo Studies
Objectives: The long-term success of root canal treatment depends not only on adequate endodontic therapy but also on the establishment of an effective coronal seal following treatment. Coronal microleakage remains a major pathway for reinfection and endodontic failure. This systematic review assessed in vivo clinical evidence on root canal coronal sealing strategies, with emphasis on intra-orifice barriers, immediate sealing, and endodontic outcomes.
Methods: This systematic review was conducted in accordance with PRISMA 2020 guidelines and prospectively registered in PROSPERO. Electronic searches were performed in PubMed/MEDLINE, Scopus, Web of Science Core Collection, CINAHL, and Cochrane CENTRAL from database inception to the final search date of July 14, 2025. Randomized controlled trials and prospective or retrospective clinical studies evaluating coronal sealing strategies following root canal treatment in permanent teeth, with a minimum follow-up of 12 months, were included. Risk of bias was assessed using established tools for randomized and non-randomized studies. Due to substantial clinical heterogeneity, a narrative synthesis was performed.
Results: A total of 531 studies were screened, of which 27 full-text articles were assessed for eligibility; 17 clinical studies met the inclusion criteria. Randomized clinical evidence did not demonstrate a consistent additional short-term benefit of intra-orifice barrier placement on endodontic healing when an effective coronal seal was achieved. Observational studies reported favorable outcomes associated with intra-orifice barrier use in selected high-risk clinical scenarios, including cracked teeth or delayed definitive restoration. Immediate coronal sealing strategies were generally associated with favorable clinical outcomes.
Conclusions: Current clinical evidence establishes that immediate coronal sealing with definitive restorations is associated with improved endodontic outcomes by preserving coronal integrity and preventing reinfection. When an effective coronal seal is achieved, available evidence does not demonstrate a consistent additional benefit from intra-orifice barrier placement. Due to the limited number and heterogeneity of clinical studies evaluating intra-orifice barriers, their potential incremental benefit remains inconclusive, highlighting the need for well-designed, long-term randomized clinical trials.
Nandini Varma
Faculty Mentors: Dr. Daniel Chan
Department: Department of Restorative Dentistry
Title: Reversal Of Doxycycline Staining – Can It Be Accelerated?
Objectives: Doxycycline is a potent tetracycline congener with ability to stain both deciduous and permanent teeth. Clinically, stained teeth can be bleached to a lighter shade with a 6-month peroxide treatment protocol.
The aim of the study is to evaluate whether UV and Infra-Red light can accelerate the bleaching action of sodium dithionite and hydrogen peroxide on doxycycline staining.
Methods: Saturated Doxycycline Hyclate power in distilled water solution has been exposed to visible light for 6 months to achieve oxidation color change. Sodium Dithionite (SD) at concentrations of 3%, 6%, and 9%. and Hydrogen peroxide (HP) at of 5%, 10%, and 15% were prepared. 24 cell culture wells were filled with the brown-grey oxidized solution accordingly and different concentration of DW and HP were added. Measurement of color changes were completed using the spectrophotometer at time intervals – T= 0, 30, 60, 90. Experiment were repeated with UV light & Infrared light (Total of 9 plates for 3 groups)
The color assessment was completed with a colorimeter (CR200, Konica, Minolta).The difference of L*, a*, b* at each period of bleaching is represented under ΔL, Δa, Δb respectively. The color difference (ΔE) was calculated by the following equation: ΔE = [(ΔL)2 + (Δa)2 + (Δb)2 ]½ . The mean ΔE were compared with multiple ANOVA.
Results: The results are summarized in Table 1. The two different bleaching systems did not show significant color improvement (ΔE decreased) at all time periods compared to pre-treatment color change. (P< 0.05).
Conclusions: Under the condition of this study, both SD and HP systems did not change the color in the short time periods even with exposure to UV and Infrared lights. Other factors such as pH& temperature may play an important role.
Kimia Imani
Faculty Mentors: Dr. Donald Chi
Department: Oral Health Sciences
Supported By: T90 DE021984
Title: Caregiver Bandwidth and Children’s Oral Health: A Proposed Qualitative Systematic Review and Research Agenda
Objectives: Children whose caregivers face psychological, social, financial, or environmental challenges may be at increased risk for dental caries due to constrained caregiver bandwidth. This proposal aims to conduct a qualitative systematic review of the international literature on caregiver bandwidth and related constructs in regard to children’s oral health, identify measurement gaps, and inform future caregiver bandwidth–focused research priorities.
Methods: This scoping review will follow the Arksey and O’Malley methodological framework to systematically identify and screen relevant studies published between 1970 and 2026. A comprehensive search strategy will target studies examining caregiver “bandwidth” in the context of child caregiving, including related constructs reflected in article titles and abstracts. Example of search terms will include cognitive and psychological bandwidth, cognitive and mental load, mental and emotional capacity, burnout, burden, strain, resilience, capability, and psychosocial influences. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines will be followed.
Results: Preliminary findings suggest that approximately ten studies will be included in the qualitative systematic review. The literature contains measures that are conceptually related to caregiver bandwidth, including caregiver burden, parental self-efficacy, caregiver stress, mental illness, household chaos, and sense of coherence, while highlighting gaps in existing measurement approaches. It is anticipated that current measures fail to capture caregiving capacity as a multidimensional, integrative construct, including the cognitive, psychological, and functional resources caregivers draw upon to support their child’s oral health.
Conclusions: The anticipated findings underscore the absence of an integrative, multidimensional framework for conceptualizing caregiver bandwidth. Additional work is needed to develop a conceptual model of this construct.
Elissa Elmorr
Faculty Mentors: Dr. Jeffrey McLean, Dr. Kristopher Kerns
Department: Department of Periodontics, Oral Health Sciences
Supported By: U01 DE027629, T90 DE021984
Title: Microbial Effects of an Added-Sugar Intervention in Alaskan Native Children
Objectives: Determine the change in supragingival plaque microbial composition from an intervention to reduce sugar-sweetened fruit drinks in Alaska Native children.
Methods: Change in the supragingival plaque composition of rural Native Alaska children from three communities participating in a longitudinal intervention trial to reduce sugar-sweetened fruit drinks was assessed. Communities A and B received the intervention while Community C served as a control group. Supragingival plaque was collected from labial incisors (N=117, aged 1 to 11 years from 66 households) using dental micro-brushes at baseline and 6 months (post-intervention). DNA was extracted, the V3-V4 hypervariable region (~460 bp) of the 16S rRNA gene was amplified and sequenced on an Illumina MiSeq (600 cycles) with positive and negative controls. Raw paired-end sequences were imported to Qiime2, denoised using the DADA2 algorithm, for exact amplicon sequence variants (ASVs) and assigned taxonomy using the eHOMD. Alpha diversity within and between communities was evaluated using the Inverse Simpson Index and assessed using Generalized Estimating Equations linear regression (α = 0.05).
Results: Within each group, Community A showed a statistically significant increase in alpha diversity between baseline and 6 months (p=0.017), and the mean diversity increased in Community B but was not statistically significant (p=0.308). Community C showed no statistical significance (p=0.602). Changes between communities were not statistically significant (p=0.378).
Conclusions: Overall, our results highlight that the intervention targeting added sugar-sweetened fruit drinks in rural Alaska Native communities may be associated with community-specific increases in alpha diversity within supragingival dental plaque, which has been shown to be an indication of a healthier microbial community composition.
Dr. Alireza Sadr
Department: B4T Lab, Department of Restorative Dentistry
Supported By: This project was partially funded by Dentsply Sirona
Title: Evaluation of Deep Class II Composite Placement Techniques Using OCT and Microtensile Bond Strength Testing
Objectives: This study evaluated post-polymerization defects and bond strength in deep Class II MOD restorations using Optical Coherence Tomography (OCT) and Microtensile Bond Strength (MTBS) testing across different composite placement techniques.
Methods: MOD cavities (5 mm deep) were prepared in extracted human molars in 4 groups: BULK: Selective enamel etching and Prime&Bond Active, single increment of TPH Spectra (Dentsply Sirona); LAYER: Selective enamel etching and Prime&Bond Active, 2-mm increments of SDR flow+ (Dentsply Sirona) followed by a final TPH Spectra layer; CIRCULAR: Selective enamel etching and Prime&Bond Active, 2-mm SDR flow+ base, circular increments of TPH Spectra for walls, and a final occlusal increment; INJECTION: Total etch and ScotchBond Universal heated Filtek Bulk Fill Flowable and Filtek One Bulk Fill Restorative (3M) using the injection molding technique. Each specimen was scanned using Dental OCT (Yoshida) and analyzed for defects, then sectioned for MTBS testing of the central beams. OCT data was analyzed using Kruskal–Wallis and MTBS data were analyzed using ANOVA followed by pairwise analyses (alpha=0.05).
Results: OCT (Figure) revealed significant differences in dentin gaps, marginal deficiencies, and stress cracks (p<0.005). BULK showed the most defects, which was significantly different from other groups. INJECTION showed significant presence of flowable composite on marginal ridge (P<0.001) and occlusal surfaces (p<0.05). MTBS ranged from 0 MPa (frequent pretest failures in BULK) to 85 MPa in CIRCULAR, which showed significantly higher bond strength than other groups (p<0.001). No significant difference was observed between LAYER and INJECTION (p>0.05).
Conclusions: The bulk technique resulted in the highest failure rates, including stress cracks and poor bonding. The circular layering method known as ASCRPT, improved bonding to deep dentin and marginal adaptation. The heated injection molding approach did not improve bond strength while presence of the weaker flowable composite was detected on occluding surfaces.
Nafiseh Najmafshar
Faculty Mentors: Dr.Alireza Sadr
Department: Restorative Dentistry
Supported By: B4T Lab
Title: Optimizing Bond Strength of UHMWPE Fibers in Composite Restorations
Objectives: Ultra-high molecular weight polyethylene (UHMWPE) fibers are used in restorative dentistry to reinforce direct restorations, bridge structural cracks, and reduce polymerization shrinkage stress. However, the optimal bonding protocol for integrating UHMWPE into composite materials remains unclear. This study aimed to identify the most effective pretreatment strategy for UHMWPE fibers in direct composite restorations using the pull-out bond strength test (POBS).
Methods: POBS of plasma-treated leano-weaved UHMWPE fiber (Ribbond Ultra 3mm, Seattle, WA) bonded onto standardized base composite patties was measured across 12 pretreatment groups: G1: unfilled resin (Ribbond Wetting Resin); G2: adhesive resin (Clearfil SE Bond2 bonding); G3: silane (Clearfil Ceramic Primer) followed by G2; G4: universal adhesive (Clearfil Universal Bond Quick2); G5: universal adhesive (Scotchbond Universal); G6: filled adhesive (Optibond FL); G7: flowable composite (Majesty Flow); G8: flowable composite with G2; G9: flowable composite with G3; G10: flowable composite with silane only; G11: hybrid composite (GrandioSO) with G2; G12: hybrid with G3. Failure modes and specimen integrity were assessed using optical coherence tomography (Yoshida Dental OCTINA).
Results: Mean POBS values ranged from 29 to 113 MPa. One-way ANOVA revealed significant differences among groups (F=175, p=.000). The lowest POBS was observed when no adhesive was applied (G7, G10, p<.001), while the highest values were achieved in groups treated with adhesive in combination with composite (G8, G9, G11, and G12). The addition of a separate silane agent to the adhesive significantly improved POBS, with the highest value observed in G12 (p<.05). The filled adhesive (G6) demonstrated higher bond strength than other adhesives (G1, G2, G4, and G5, p<.05). Pretest internal defects were observed in G7 and G10. Failure modes indicating cohesive failure of the base patty substrate were noted in G9, G11, and G12.
Conclusions: UHMWPE fiber bonding was most effective when adhesive was combined with a highly filled composite (Chyz technique), enabling precise fiber placement. Silanization provided a modest but consistent enhancement in POBS, which may improve long-term performance.
Youkyung (Julie) Kim
Faculty Mentors: Dr. Barbara Sheller
Department: Orthodontics
Supported By: Department of Orthodontics, University of Washington School of Dentistry
Title: Long-term stability of skeletal, dental, and facial esthetic changes with rigid external maxillary distraction osteogenesis
Objectives:Maxillary distraction osteogenesis using a rigid external distraction device (MDO-RED) is a treatment option to correct severe maxillary hypoplasia in patients with craniofacial anomalies. However, existing literature on long-term stability is limited by small cohorts and brief follow-up periods. This study evaluated the long-term skeletal, dental, and facial esthetic outcomes following MDO-RED.
Methods: We reviewed consecutive patients treated with Le Fort I level MDO-RED at Seattle Children’s Hospital between 2008 and 2023. Records, including lateral cephalograms, dental models, and extraoral photographs, were evaluated at four intervals: pre-operative (T1), immediate post-operative (T2), first follow-up (T3), and the furthest available follow-up (T4). Cephalometric analysis was performed using Dolphin Imaging Software. A Cartesian grid was established with the x-axis 7 degrees below the sella-nasion line and the y-axis perpendicular to the x-axis passing through sella. Changes in the position of A-point within the coordinate grid was used to assess the change in the maxillary position.
Results: Sixty-one patients (mean age at T0: 14.8 +/- 1.7 years; 44 males, 17 females) were included in the analysis. Mean A-point advancement at T1 was 12.9 +/- 5.1mm. At T2, with a mean duration of 1.9 years, horizontal relapse at A-point averaged 32.1 +/- 28.9%. At T3, with a mean duration of 4.2 years, horizontal relapse at A-point increased to 46.7 +/- 45.7%. Overjet improved from -10.8 +/- 4.2mm at T0 to 3.1 +/- 3.5 at T1, followed by reduction to -1.8 +/- 6.0mm at T2 and -3.2 +/- 5.0mm at T3. Similar improvements in overbite, molar classification, and crossbites were observed from T0 to T1, with partial relapse at T2 and T3. Distance of upper lip to E-line increased from -9.2 +/- 3.9mm at T0 to 0.3 +/- 4.8mm at T1, followed by reduction to -4.3 +/- 4.2mm at T2 and -5.7 +/- 4.0mm at T3. Other facial esthetic measures, including profile angle and nasolabial angle, showed similar trend. At T3, 22 patients underwent further orthognathic surgery to correct residual skeletal malocclusion, and 31 patients required no additional surgery or remained under long-term observation.
Conconclusions: MDO-RED can effectively advance the maxilla to correct maxillary retrusion and achieve substantial improvements in occlusal relationships and facial esthetics. Progressive relapse is observed over time, however, due to maxillary instability and continued mandibular growth. These findings highlight the need for long-term follow up to monitor treatment outcome and identify candidates for retreatment with definitive orthognathic surgery.
Hsin-Lin Lee
Faculty Mentors: Kwok-Hung Chung and Jonathan An
Department: Oral health department
Supported By: GCRLE-0120, P51 OD 011092
Title: Effect of Rapamycin Treatment on Aged Non-Human Primate Teeth
Objectives: To assess the effects of Rapamycin treatment on the fracture resistance and structural components of aged non-human primate (NHP) teeth.
Methods: NHP samples were sourced from animals used in prior approved collections, and no additional animal procedures were conducted. Eleven NHPs were used in this investigation and divided into three groups, Group Y: Four young NPHs (4-6 years old, teeth number=17), Group O: Three old NHPs (17-19 years old, teeth number=23), and Group OR: Four old NHPs (17-19 years old, teeth number=30) treated with Rapamycin via intramuscular injections (1.02 mg/kg) twice a day for 10 months. Blocked sections of maxillary and mandibular first and second premolars, along with approximately 10mm×8mm periodontium, were harvested for this study. After embedding using acrylic resin, specimens with teeth plus periodontium were subjected to fracture resistance test after preparing a standardized slot (1.0mm×1.0mm) meso-distally and using a universal testing machine at a crosshead speed of 1mm/min. A field emission-electron probe microanalyzer was used to analyze representative fracture specimens using a standardized protocol. Data were analyzed statistically by using ANOVA and Tukey HSD test with α=0.05.
Results: Fracture resistance values obtained range from 491.1 ± 200.9 N to 855.3 ±74.9 N. Group OR had a statistically significant higher fracture resistance force than Group O (P<0.05). Elemental analysis revealed that calcium levels remained unchanged among Group Y and Group O. Phosphorus levels decreased in Group O (P<0.05) and increased in Group OR (P<0.01) when compared to Group Y. The Calcium/Phosphorus ratio increased from 1.78 (Group Y) to 1.98 (Group O) while Group OR ratio decreased to 1.66 (P<0.01).
Conclusions: NHPs treated with Rapamycin enhanced fracture resistance and restored Calcium/Phosphorus ratio of aged teeth.
Celine Atkinson
Faculty Mentors: Dr. Jeffrey McLean
Department: Periodontics
Supported By: R21 DE032890, T90 DE021984
Title: Single-cell Transcriptional Profiling of Periodontal Pathogens Involved in Polymicrobial Synergy
Objectives: The study investigates how physical interactions between oral pathogens contribute to synergistic virulence and periodontitis progression. We focus on key impactful synergistic microbial interactions occurring within subpopulations of Fusobacterium nucleatum (FN) and Porphyromonas gingivalis (PG). By using microSPLiT, a high-resolution single-cell RNA sequencing technique for bacteria, we seek to resolve gene expression patterns that are obscured in traditional bulk RNA capture approaches.
Methods: Fusobacterium nucleatum (FN) ATCC 23726 and Porphyromonas gingivalis (PG) ATCC 33277 were co-cultured across defined time points (TPs); RT-qPCR quantified organism load and transcriptional changes between mono- and co-culture states. Phase contrast microscopy, OD600 measurements, and manual cell counts monitored physical associations and growth kinetics. RNA was extracted at each TP, and area-under-curve (AUC) analysis identified active windows.
Mock microSPLiT trials tested lysozyme concentration, detergent strength (Triton-X, Tween-20), and lysis duration. cDNA yield and cycle threshold (Ct) values revealed species-specific differences in nucleic acid accessibility.
Results: Preliminary microSPLiT differential gene expression data revealed virulence factors associated with FN:PG physical contact—fap2, radD (FN), and fimA, mfa1 (PG). Single-cell metrics averaged 25.07 genes and 29 reads per cell, supporting microSPLiT’s feasibility.
Permeabilization and lysis trials revealed that lower lysozyme, stronger detergents, extended lysis incubation and more potent lysis buffers were necessary to access intracellular RNA. RNA recovery ranged from 0.7–1 pg per cell, while leakage estimates ranged from 0.8–0.9 ng/cell for both species. Cell loss during permeabilization was ~38.89% for FN and PG ~17.93%. Optimal transcriptomic capture occurred at 22 hours (FN) and 9 hours (PG), with OD600 values between 0.3–0.4.
Conclusions: We identified optimal permeabilization conditions to access intracellular RNA within oral bacteria. Lower lysozyme, stronger detergents and extended lysis incubation improved RNA recovery for single-cell transcriptomics of human oral pathogens.
Derrick Tang
Faculty Mentors: Dr. Fritzie Arce-McShane
Department: Department of Oral Health Science, Department of Neuroscience
Supported By: T90 DE021984; ARCS Foundation; R01 DE027236
Title: Cortical encoding of lingual contacts in feeding
Objectives: Precise tongue movements during feeding rely on somatosensory feedback from the oral cavity. Neural processing of these sensory signals is crucial for regulation of tongue movements for each phase of food manipulation, chewing, and swallowing. However, the frequent self-touches between the tongue and upper oral structures during feeding phases have not yet been described due to the challenge of tracking tongue movements inside the mouth. We hypothesize that sensory information about contacts between the tongue and surrounding oral structures, such as the palate and the teeth, is critical for tongue control and thus robustly encoded in the orofacial sensorimotor cortex during feeding.
Methods: We used bilateral video radiography and implanted markers on the lingual mucosa to track 3D tongue movements and identify lingual contacts while rhesus macaques (n=3) engaged in natural feeding. Simultaneously, we recorded neuronal activity using chronically-implanted microelectrode arrays in four cortical regions: rostral primary motor cortex (M1), caudal M1, Area 3a/3b, and Area 1/2 of primary somatosensory cortex (S1).
Results: The tongue moved predominantly from posterior to anterior on the upper oral structures during all phases of feeding, and anterior to posterior strokes increased during food manipulation prior to chewing. The tongue exhibited phase-specific stroke patterns across all animals, including increased contralateral contact during sided chewing. Significant decreases in both the frequency and duration of tongue strokes (Wilcoxon rank sum test, p< 0.05) were observed after a series of nerve blocks eliminated tactile feedback from the oral cavity, but the changes in stroke pattern were subject-dependent. The majority of neurons in M1 and S1 modulate significantly during contact than between contacts (Wilcoxon rank sum test, p< 0.05), and a subset additionally modulates with the direction of contact (ANOVA, p<0.05). Loss of somatosensation reduces the portion of neurons that modulate firing rate with contact parameters across three subjects, suggesting reduced intraoral awareness.
Conclusions: These results suggest that feeding phase-specific tongue strokes against the upper oral structures rely on tactile feedback, and that the orofacial sensorimotor cortex represents lingual contacts at both individual neuron and population levels.
Azeez Fashina
Faculty Mentors: Dr. Robert Cornell
Department: Oral Health Sciences
Supported By: R01 DE023575, T90 DE021984
Title: A Proposed Kinase Cascade Upstream of IRF6 in Orofacial Cleft Pathogenesis
Objectives: Orofacial clefts affect approximately 1 in 700 live births worldwide, imposing lifelong burdens related to feeding, speech, and psychosocial well-being. Although both environmental and genetic risk factors contribute to its pathogenesis, known genetic variants account for only a fraction of the inherited risk, and many syndromic cleft disorders converge on regulators of the embryonic periderm, a transient epithelial layer essential for normal palatal fusion. Interferon Regulatory Factor 6 (IRF6) is a central transcription factor in periderm differentiation, and pathogenic variants in IRF6 and in kinases such as PRKCI, RIPK4, and IKK1 are implicated in orofacial cleft syndromes such as Van der Woude and popliteal pterygium syndrome. The overarching objective of this work is to define a kinase cascade involving PRKCI, RIPK4, and IKK1 that converges on IRF6 activation to control periderm differentiation, thereby providing a mechanistic link between diverse cleft syndromes and suggesting new diagnostic and therapeutic targets.
Methods: Zebrafish embryos were used as an in vivo model for periderm and craniofacial development, leveraging the conservation between zebrafish EVL/periderm and mammalian periderm, including shared regulatory genes. To interrogate kinase function, a panel of loss‑of‑function and gain-of-function tools was employed in wild‑type and kinase‑deficient zebrafish embryos, with periderm integrity and rupture phenotypes as primary readouts. Future work will incorporate biochemical assays, including in vitro kinase assays and mass spectrometry, to define direct/indirect interactions and phosphorylation patterns between these kinases and IRF6.
Results: Preliminary zebrafish data and published work demonstrate that PRKCI activity is required for periderm integrity and that pharmacologic inhibition of PRKCI leads to a rupture phenotype that can be rescued by overexpression of constitutively active (CA)‑IRF6, placing IRF6 downstream of PRKCI in this pathway. Additional experiments show that the periderm rupture phenotype induced by PRKCI inhibition is also rescued by CA‑RIPK4 and CA‑IKK1, supporting a model in which these kinases function downstream of, or in parallel with, PRKCI to promote periderm differentiation. While RIPK4‑mediated phosphorylation of IRF6 is well established, our current work is directed at defining how PRKCI interfaces with RIPK4 and testing whether IKK1 directly phosphorylates the known activating serines in IRF6. These studies are ongoing, with biochemical mapping of phosphorylation sites and genetic interaction experiments underway.
Conclusions: This work proposes that PRKCI, RIPK4, and IKK1 form a kinase network upstream of IRF6 that is required for proper periderm differentiation and, consequently, for normal craniofacial morphogenesis. By mechanistically linking multiple cleft‑associated kinases to a shared IRF6‑centered pathway, this model has the potential to explain some of the “missing heritability” in orofacial clefting, account for the broad and overlapping clinical phenotypes seen across distinct syndromes, and guide more precise molecular diagnoses. As these kinase‑IRF6 interactions are validated and mapped in detail, they may also reveal druggable nodes that could eventually support risk stratification, prevention strategies, or targeted therapies for patients with cleft lip and palate and related craniofacial anomalies.
Ana Luiza Peres Baldiotti
Faculty Mentors: Donald L. Chi
Department: Oral Health Sciences
Supported By: National Institute of Dental and Craniofacoa; Research (NIH/NIDCR): R01DE026741
Title: Caregivers’ Political Affiliation and Opposition to Topical Fluoride and Water Fluoridation
Objectives: This cross-sectional study aimed to explore the association between caregivers’ political affiliation and their opposition to topical fluoride and water fluoridation for their children.
Methods: This study was conducted at the University of Washington (UW) in collaboration with the University of California Los Angeles, Boston Children’s Hospital, University of Iowa, and through social media platforms. Caregivers who spoke English and with at least one child under 18 participated in the study by completing an online questionnaire. The survey included questions about their beliefs regarding CWF (oppose or in favor), topical fluoride (oppose or in favor), political views (conservative, moderate, or liberal), and demographic information. Descriptive, bivariate, and adjusted logistic regression analyses were conducted using RStudio (version 12.1), with a significance level set at p < 0.05.
Results: A total of 883 caregivers participated in the study, with a mean age of 41 years (SD = 8). Among them, 20% were men, 79.5% were women, and 0.5% were non-binary. Most participants (98.3%) completed high school. In terms of political affiliation, 13% identified as conservative, 39% as moderate, and 48% as liberal. Caregivers with moderate political affiliation (p = 0.049) had 37% lower odds of opposing topical fluoride compared to those with conservative political affiliation (OR = 0.63, 95% CI: 0.39 – 1.00; p = 0.049). Caregivers’ political affiliation was not significantly associated with CWF opposition (p > 0.05).
Conclusions: Findings suggest that conservative caregivers are more likely to oppose topical fluoride but not CWF. Future studies are needed to identify underlying reasons.
Gulaiim Almatkyzy
Faculty Mentors: Dr. Donald Chi
Department: Oral Health Sciences
Supported By: T90 DE021984
Title: Alaska Native Caregivers’ Practices and Perspectives on Children’s Toothpaste Use
Objectives: To qualitatively explore Alaska Native caregivers’ practices and perspectives on children’s toothpaste use, access to toothpaste, and knowledge and concerns about fluoride toothpaste.
Methods: Twenty-nine interviews were conducted with Yup’ik caregivers as part of a socio-behavioral intervention in three Alaska Native communities. Using inductive thematic analysis, 14 categories were organized into four domains: children’s toothpaste use, children’s toothpaste flavor preferences, caregiver experience obtaining toothpaste, and caregiver perceptions of fluoride toothpaste.
Results: Most caregivers (86%) reported that their children use toothpaste every time they brush, while 14% indicated that their children prefer brushing without toothpaste. However, only 19% of children brush twice daily. In some households, when children’s toothpaste was unavailable, children used adult toothpaste. In about one-quarter of households, adults and children shared the same toothpaste. More than one-half of caregivers reported that their children preferred mint-flavored toothpaste, describing it as having a more ‘grown-up’ taste. Others found mint ‘too hot,’ giving a ‘chilling effect,’ and preferred non-mint flavors. Children also liked watermelon- and bubble gum- flavored toothpastes. Caregivers obtained toothpaste primarily from local stores, although some identified high cost or limited availability as barriers. They also received free toothpaste during dental clinic visits or purchased additional supplies while traveling to larger cities. A few caregivers ordered toothpaste online because of lower prices and a wider selection. Most caregivers had no concerns about fluoride, but their understanding of its protective role was limited. While most used fluoride toothpaste, many were unsure whether their toothpaste contained fluoride. Two caregivers expressed concerns about fluoride’s potential long-term side effects.
Conclusions: Although most Alaska Native children use toothpaste, low toothbrushing frequency and limited caregiver awareness of fluoride toothpaste indicate opportunities for public health interventions to improve daily toothbrushing routines with fluoride toothpaste.
Edric Tsang
Faculty Mentors: Shreyas Punacha, Fritzie Arce-McShane
Department: Oral Health Sciences
Supported By: National Institute of Aging R01AG069227
Title: Motor Drive and Sensory Feedback Shape Orofacial Muscle Representation in the Primary Motor Cortex
Objectives: Precise control of jaw and tongue muscles is essential for efficient feeding, speech, and communication. These behaviors rely on coordinated activity within the orofacial sensorimotor cortex, yet the spatial organization of cortical zones governing individual muscles aren’t completely understood. Although jaw muscle representation in the orofacial primary motor cortex (M1o) has been previously documented, tongue muscle mapping has not been systematically explored. The objective of this study is to characterize somatotopy of tongue and jaw muscles in M1o using subthreshold intracortical micro-stimulation (ICMS), and to assess how sensory input modulates these motor maps. We hypothesize that muscles activated by subthreshold ICMS exhibit graded sensory dependence based on their specific contribution to behavioral functions.
Methods: One aged male rhesus macaque was chronically implanted with a Utah electrode array in M1o. Bipolar EMG recordings were obtained from 13 orofacial muscles via fine intramuscular wire electrodes. Post-processed EMG activity was considered significant if it exceeded mean baseline activity by a fixed threshold of 5 standard deviations. ICMS responses were visualized as activation matrices across three experimental days: control (intact sensory input), full nerve block (suppression of oral tactile inputs), and selective nerve block (preserved lingual tactile inputs). Overlap between activation matrices was quantified using Jaccard, Dice, and simple matching coefficients (SMC). Differences in cluster activation were assessed using Kruskal–Wallis ANOVA followed by Dunn’s post-hoc tests with false discovery rate correction.
Results: ICMS reliably evoked activity in tongue and jaw muscles in 40.66% of stimulated electrodes, revealing distinct and partially overlapping zones in muscle motor maps. Agglomerative clustering and dendrogram analyses identified clusters of electrodes that showed similarities in ICMS-induced muscle activation, which were projected onto the 2D cortical grid. Similarity metrics showed moderate reproducibility across ICMS sessions (coefficients: 0.23-0.77), despite varying experimental conditions based on available somatosensation. However, cluster analysis revealed stable spatial and muscle-specific patterns of co-activation and sensory dependence: the Right Styloglossus showed strong activation in the medio-posterior zone of M1o when the lingual nerve was intact (Kruskal-Wallis p<0.001, Dunn’s p<0.001), but weak activation under full nerve block, suggesting a fast-rate of reafference of muscle activity via lingual afferents. In contrast, the left Genioglossus exhibited weak activation in lateral zones across all conditions, indicating motor-driven responsiveness independent of sensory input. Cortical zones located closer to the central sulcus, corresponding to caudal M1o, exhibited stronger activation under intact sensory conditions and diminished responses under full nerve block, suggesting these regions are more dependent on afferent input.
Conclusions: ICMS mapping reveals that cortical representation of tongue muscles in M1 are both spatially organized and differentially modulated by sensory input. Spatial clustering of co-activation patterns highlight functional organization in which motor control emerges from regionally distinct zones rather than diffuse, overlapping areas. These findings suggest that muscles with sensory-dependent cortical zones may rely on afferent feedback loops for normal function. Given that sensory processing deteriorates early in neurodegenerative conditions such as Alzheimer’s, this offers insight into the neural basis underlying the decline in speech, feeding, and motor control.
Quinton Springer
Faculty Mentors: Dr. Jeffrey McLean
Department: Periodontics
Supported By: The project was funded by an unrestricted gift to the University of Washington from Elevate Oral Care, LLC.
Title: Quantifying In-Vitro Antimicrobial Effects of 38% Silver Diamine Fluoride (SDF) Gel on Porphyromonas Gingivalis 33277
Objectives: The aim of this study is to identify the inhibitory concentration of a new gel formulation of silver diamine fluoride (SDF) against Porphyromonas gingivalis 33277 and characterize its potential use as an effective application for treatment of gingivitis and periodontitis.
Methods: An in-vitro modified Kirby–Bauer lawn assay was conducted using Porphyromonas gingivalis 33277 grown on blood agar plates under anaerobic conditions. Serial dilutions (10⁻¹–10⁻⁶) of 38% gel SDF were prepared using sterile double-distilled water and applied to bacterial lawns via sterile micro-brushes with technical replicates. Plates were incubated at 37°C for 24 hours and zones of inhibition (ZOIs) were measured to determine the effect from the inhibitory concentrations.
Results: After 24 hours of anaerobic incubation, the inhibitory concentration for SDF against P. gingivalis 33277 was determined to be between 0.38% and 0.038% SDF. Clear ZOIs were observed in this concentration range, while lower concentrations failed to inhibit bacterial growth. 38% gel SDF demonstrates strong dose-dependent antimicrobial activity against P. gingivalis 33277 in vitro, with inhibition observed at concentrations as low as 0.038%.
Conclusions: SDF has been proven to have bactericidal effects on supragingival cariogenic bacteria. Limited studies to date have evaluated the bactericidal effects of SDF on subgingival periodontal disease associated pathogens. A new gel formulation of SDF has been developed, and this study was designed to quantitatively determine the inhibitory concentration of SDF gel on Porphyromonas gingivalis (Pg). Pg is a well-established keystone periodontal pathogen associated with periodontal inflammatory diseases including gingivitis and periodontitis. Disrupting Pg may beneficially impact the subgingival community and reduce disease progression and severity.
Valencia Tang
Faculty Mentors: Dr. Zi-Jun Liu, Doris H. Rosero Salazar
Department: Orthodontics
Supported By: R01 DE028864
Title: Respiratory Kinematics of the Tongue Base with reduced and enlarged volumes in minipigs
Objectives: The aim of this study was to examine the respiratory 3D deformational changes in the tongue base with reduced and enlarged volumes in a minipig model.
Methods: This study included 6 same-sex sibling pairs (3 pairs each sex) of Yucatan minipigs 8-to-9 months old. Of each pair, one minipig was a normal weight with a BMI < 35 and received surgical volumetric reduction of the tongue base (Reduction), and the other was fed a special diet to reach obesity with a BMI > 50 (Enlargement). Under sedation, eight 2mm ultrasonic piezoelectric crystals with an extended skin button attached to the back were surgically implanted at the base of the tongue in a cubic-shaped configuration. The assigned crystal pairs represented bilateral dorsoventral lengths and anteroposterior, as well as bilateral anteroposterior thicknesses of the tongue base. Thus, the 3D deformational changes of the tongue base were recorded during respiration using a Sonometric system together with synchronized electromyography (EMG) and respiratory airflow recordings to identify respiratory phases. The longitudinal recordings were repeated at the baseline before the surgery, and 1, 3, and 5 weeks after the surgery. The amplitudes and durations of each dimensional change within the crystal-defined region concerning inspiration were calculated for 5 consecutive respiratory cycles per animal.
Results: The enlargement group showed longer respiratory cycle and inspiratory durations compared to the reduction group. The reduction was associated with smaller, coordinated dorsoventral, anteroposterior, and thickness changes during inspiration. In contrast, the enlargement group exhibited greater deformational amplitudes, particularly in the dorsoventral and thickness dimensions, along with prolonged deformation duration and increased variability. These group-specific patterns were consistent across post-baseline time points.
Conclusions: Preliminary findings indicate that tongue volume influences respiratory dynamics of the tongue base. Volume-enlarged tongue base volume is associated with exaggerated and prolonged deformation during inspiration, whereas volume-reduced results in more constrained and efficient kinematic patterns. These findings enhance understanding of the impacts of volumetric alterations of the tongue base on the respiratory function, with clinical.
Jake Ferguson
Faculty Mentors: Dr. Sumita Jain, Dr. Sarah Alaei
Department: Periodontics, School of Dentistry, and Department of Science and Mathematics, UW, Tacoma
Supported By: R01 DE032027
Title: Co-culture of P. gingivalis and F. nucleatum alters outer membrane vesicle formation and increases TLR4-dependent immune stimulation relative to mono-culture
Objectives: Porphyromonas gingivalis (Pg) is a Gram-negative, coccobacillary, anaerobic bacterium commonly found in the oral cavity, particularly in the sub-gingival crevice. It is a causative agent of periodontal disease, and has been implicated in exacerbating inflammatory conditions such as cardiovascular disease, atherosclerosis, and Alzheimer’s disease. Fusobacterium nucleatum (Fn) is also an anaerobic bacterium found in the sub-gingival crevice associated with similar inflammatory comorbidities. Pg is notable for prolific outer membrane vesicle (OMV) formation, as well as its modification of lipid A, a crucial part of lipopolysaccharide (LPS), an essential macromolecule which is present in bacterial outer membranes (OMs) and, consequently, in OMVs. The modification produces lipid A which does not stimulate toll-like receptor 4 (TLR4), an innate immune receptor in host cells. OMVs are known to contribute significantly to Pg pathogenesis. We showed previously that Pg OMVs contain predominately TLR4 stimulatory lipid A, in contrast to the OMs from which they are derived which contain primarily non TLR4 stimulatory lipid A. This dichotomy allows the bacterium to evade TLR4 mediated immune responses while OMVs act as a ‘decoy’, stimulating TLR4 and promoting inflammation. Here we investigated OMV production and contribution to virulence when Pg was co-cultured with Fn.
Methods: To investigate the interaction between Pg and Fn, we grew Pg 381 and Fn 25586 in mono-culture or co-culture and evaluated relative levels of OMV production by transmission electron microscopy (TEM). Next, we isolated OMVs derived from Pg and Fn mono- and co-cultures by ultracentrifugation. We evaluated TLR4 activation by both whole bacteria and bacterial OMVs from mono- and co-cultures by HEK TLR4 luciferase assays.
Results: TEM demonstrated that Pg makes more OMVs than Fn. TEM images of co-cultures showed both Pg and Fn whole bacteria present, but notably lacked the abundant OMVs seen in Pg mono-culture. We found that Pg and Fn co-cultured whole bacteria, and their OMVs, stimulated TLR4 higher than Pg or Fn alone.
Conclusions: Our results demonstrate an inhibition of OMV biogenesis in Pg-Fn co-culture relative to either mono-culture, possibly by substances released in the supernatant. We also showed heightened stimulation of TLR4 by Pg and Fn co-culture suggesting a change in the structure of lipid A, the primary TLR4 agonist. These findings have applications for further studies examining interactions between Pg and other pathogens as well as investigating the mechanism responsible for the modulation of lipid A structure and OMV production.