Journal of Dental Research

Objective. A deep learning (DL) model was used to convert smartphone videos of a complete arch implant cast into 3D scans. The aim of current study was to determine if a custom scan body (SB) with geometric features and coating would outperform regular PEEK stock SB in this DL scenario. The DL-derived scan outcomes were compared with those obtained from a conventional splinted open-tray impression and from photogrammetry. Materials and Methods. A maxillary edentulous model with six implants and multi-unit abutment analogs was scanned using four protocols: conventional splinted open-tray impression (CO), photogrammetry (PG; Icam4D), DL using stock SBs (DLS) and DL using custom SBs (DLC). Each protocol was repeated for 10 times. The DL scans were produced from smartphone videos with a high-fidelity, multi-view 3D construction AI model (Neuralangelo). The custom designed SB incorporated geometric features and was fabricated via 3D printing followed by a spray coating. Accuracy (trueness and precision) was assessed using three measurements: Root Mean Square (RMS), linear deviation, and angular deviation. Results. DLC outperformed DLS in both trueness and precision regarding RMS and linear measurements (p<0.001). CO and PG demonstrated the highest RMS and linear trueness, with no significant difference between them (RMS: p=0.93; linear: p=0.663). PG achieved the best precision across RMS, linear and angular measurements. Conclusion. The optimised SB significantly improves the accuracy of DL-based approach for full-arch implant scan comparing to regular PEEK stock scan bodies. While early stage, neural surface reconstruction has potential as a viable option for full-arch implant rehabilitation.

Abstract Aim: To test whether neighbouring-tooth restorations affect a focal tooths periodontal status (within-mouth spillover), and whether accounting for them alters the established association at the restored surface. Materials and methods: Prospective tooth-surface data from the Study of Health in Pomerania (SHIP): SHIP-START (N=2,715/1,982/1,397, follow-ups 1-3) and SHIP-TREND (N=2,123). Own and neighbouring-tooth restoration were defined at baseline; probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP) and deep pockets (PD >=4 mm) at follow-up. A neighbourhood-exposure mixed model with generalized propensity-score adjustment estimated both effects, with two corroborating estimators. Results: Own restoration was associated with worse periodontal status at that surface (crown PD exp(beta) up to 1.10). Neighbouring-tooth restorations raised focal-tooth PD (spillover exp(beta) 1.03-1.05) and deep-pocket risk (risk ratio up to 1.25); CAL and BOP showed none consistently. It attenuated with tooth-lag, nearing the null by two to three teeth in most estimators. Ignoring interference modestly inflated the direct effect; an opposing-tooth negative control showed none; untreated caries reproduced it. Conclusions: Dental restorations exert a within-mouth spillover on neighbouring-tooth PD: their periodontal footprint extends beyond the restored tooth. The direct association persists, modestly attenuated, after accounting for the neighbourhood.

Background: Subepithelial connective tissue grafting remains a reference treatment for predictable root coverage. Although short- and medium-term outcomes of tunnel-based procedures are well documented, evidence regarding stability beyond 10 years remains limited. This study evaluated the long-term clinical performance of a minimally invasive tunnel technique combined with subepithelial connective tissue grafting (SCTG) under routine clinical conditions. Methods: This retrospective longitudinal cohort study included 74 patients (57 women and 17 men) contributing 710 gingival recession sites treated between 2009 and 2025. All sites were treated with a tunnel approach and SCTG, with enamel matrix derivative (EMD) used in selected cases. The mean follow-up was 6.0 for 4.0 years, with a maximum observation period of 16 years. The primary outcome was recession depth reduction. Secondary outcomes included complete root coverage (CRC), mean root coverage, and long-term marginal stability. Clinically relevant relapse was defined as a 1 mm increase in recession after initial healing. Results: Mean recession reduction was 2.72 mm. Complete root coverage was achieved at 83.4% of treated sites. At the final available follow-up, no treated site showed a clinically relevant relapse of 1 mm after initial healing, and no site deteriorated beyond its baseline recession level. Treatment effects were observed across anterior and posterior regions. Conclusions: Within the limitations of a retrospective cohort design, tunnel surgery combined with SCTG was associated with high root-coverage predictability and durable marginal soft-tissue stability for observation periods extending to 16 years. These real-world data support phenotype-enhancing, minimally invasive soft-tissue augmentation as a durable therapeutic strategy for localized and multiple gingival recessions. Keywords: gingival recession; tunnel technique; subepithelial connective tissue graft; root coverage; periodontal plastic surgery; long-term stability

Objectives: Dentists prescribe approximately one in ten antibiotics worldwide, yet antimicrobial stewardship (AMS) remains underemphasized in dental education. Large language models (LLMs) may support AMS training, but their proficiency and clinical reasoning in this context remain unclear. We evaluated GPT-4o's accuracy and clinical reasoning on dental antibiotic prescribing questions, stratified by question difficulty. Methods: We assembled 125 multiple-choice questions on dental antibiotic prescribing from eight peer-reviewed studies (2017-2023). GPT-4o answered each question and generated a clinical justification. Accuracy was assessed against source-study answer keys and examined across difficulty quartiles. Justifications were evaluated using an adapted 12-axis human-evaluation framework assessing scientific consensus, extent and likelihood of harm, inappropriate and missing content, bias, and both correct and incorrect comprehension, retrieval, and reasoning. Prophylaxis-specific questions were analysed separately. Results: GPT-4o correctly answered 72% of questions. Accuracy remained relatively stable across difficulty quartiles (78%, 78%, 65%, 70%). Experts rated 95.4% of justifications positively across the 12 axes. Comprehension, retrieval, and reasoning each exceeded 96.2% positive ratings. Missing content was the main weakness (7.8%), and 7.1% of justifications showed a moderate-to-severe potential for harm. Performance on prophylaxis-specific questions (98.1%) exceeded non-prophylaxis questions (93.0%). Conclusions: GPT-4o demonstrated moderate-to-high proficiency and clinically defensible reasoning in dental antibiotic prescribing questions. However, residual risks indicate that it is not suitable for unsupervised clinical use but shows potential as a supervised AMS educational tool.

Since model dose-response is critical when assessing caries lesion development over time, this study evaluated the influence of fluoride dose and treatment duration on caries progression in a rat caries model. Streptococcus mutans-infected Sprague-Dawley rats were treated with deionized water, 226 ppm F-, or 2,260 ppm F- twice daily for 3, 4, or 5 weeks. Caries lesions were assessed using Larson's modification of the Keyes scoring system and complemented by micro-computed tomography (microCT). Intraoral fluoride availability, serum and bone fluoride concentrations and microbial counts were also determined. Fluoride reduced caries severity in a dose- and time-dependent manner. While early enamel lesions were detected in all groups, extensive dentine lesions increased over time, in a dose-dependent manner, in the control and 226 ppm F- groups, and were not observed in the 2,260 ppm F- group after 5 weeks. Intraoral and bone fluoride availability increased significantly with fluoride concentration and treatment duration, whereas serum fluoride levels reflected fluoride dose instead of treatment duration. MicroCT-derived enamel volume correlated negatively with both total and extensive caries scores, supporting its utility as an objective measure of lesion severity. In conclusion, extending model length from 3 to 5 weeks increased the severity of caries lesions in a dose-dependent manner. Fluoride intraoral availability and bone fluoride also demonstrated a dose and time-dependent response.

Background: Cone-beam computed tomography (CBCT) frequently captures the maxillary sinuses incidentally, and reliable automated detection of sinus abnormality is clinically relevant. Unlike most vision-language benchmarks in medical imaging, which pair images with pre-existing, human-authored clinical reports, findings text can also be generated directly by a large language model from the image itself--raising the question of how much diagnostic value such AI-derived text carries, and whether that value depends on independent verification. Multimodal artificial intelligence (AI) benchmarks risk overstating performance if the provenance of each input--image, raw AI-generated text, or radiologist-verified text--is not clearly separated and reported. Methods: We used 300 mid-sagittal CBCT slices from the MMDental dataset. ChatGPT generated findings text and a provisional normal/abnormal label for every slice (majority vote, three independent readings from the image alone); primary classification performance was assessed on this full, unfiltered set (n=300). A radiologist then independently reviewed each case's image together with ChatGPT's description, producing their own diagnosis; three cases were excluded as insufficient, yielding 297 confirmed cases. On this subset, every model was retrained and re-evaluated under identical 10-fold cross-validation on both the provisional ChatGPT-only labels ("pre") and the radiologist-confirmed labels ("post"), isolating the effect of label provenance from image or architecture. Eight vision architectures, seven language classifiers, and five VLMs were evaluated throughout; three generative models performed exploratory note-drafting. Findings: Raw ChatGPT-generated text produced the highest performance of any modality or condition: language models reached near-ceiling AUC (0.992 to 1.000, n=300), exceeding every vision model (AUC 0.799 to 0.880) and every VLM image-only probe (AUC 0.63 to 0.69). On the 297-case pre/post analysis, this advantage depended heavily on label source: language and text-derived VLM performance fell substantially from ChatGPT-only to radiologist-confirmed labels (e.g. BERT-base AUC 0.999 to 0.837), while vision-model performance was stable or modestly improved (e.g. DenseNet-121 0.867 to 0.891). The radiologist reclassified 62 of 297 cases (21%) relative to ChatGPT's provisional read, and a meaningful proportion of raw ChatGPT text was clinically uninterpretable or unsupported by the imaging. Interpretation: As shown here for the first time, raw, image-derived AI-generated text yields the highest apparent classification performance in this benchmark, but this reflects the text's alignment with its own self-generated labels rather than verified diagnostic content, and a substantial share of that text is not clinically explainable. Radiologist-confirmed text and labels give a lower but trustworthy estimate of true performance, on which convolutional neural network (CNN) vision models remain a stable, comparatively inexpensive baseline. Multimodal dental AI should report performance separately by modality and label provenance rather than pooling headline metrics.

Multimodal large language models (MLLMs) are increasingly applied to image-based clinical reasoning, yet their diagnostic reliability in periodontal image interpretation, and the underlying source of their errors, remain poorly characterized. This study evaluated six architecturally distinct MLLMs (Claude Sonnet 4.5, GPT-5.0, Gemini 2.5, GLM-4.6, Sonar, and Grok 4.1) using 50 image-based multiple-choice questions drawn from the American Academy of Periodontology In-Service Examination, spanning clinical photographs, histopathology, radiographs, cardiac rhythm strips, and anatomical illustrations. A sequential two-phase experimental design was used: in Phase 1, each model independently described each image, selected an answer, and provided a supporting citation; in Phase 2, applied only to questions answered incorrectly, models were given an expert-validated visual description and asked to re-answer, allowing diagnostic improvement through visual correction to be measured directly. Expert ground truth for image content was established by a board-certified periodontist and independently validated by a second board-certified periodontist. Model outputs were classified using a dual-process error taxonomy adapted from Norman's model of diagnostic reasoning, distinguishing perceptual errors, arising from inaccurate visual feature extraction, from cognitive errors, arising from flawed reasoning despite accurate perception, with cognitive errors further subdivided into correctable and persistent subtypes, and additional categories capturing compound perceptual-cognitive failures and compensatory reasoning that overcame inaccurate perception. Diagnostic accuracy and error type distribution varied significantly across models and image modality. Correcting inaccurate visual descriptions in Phase 2 improved diagnostic accuracy for a subset of previously incorrect responses, indicating that a meaningful share of errors originated at the level of visual perception rather than clinical reasoning; conversely, a distinct subset of errors persisted despite accurate corrected visual input, indicating reasoning-level failures independent of perceptual accuracy. Some models also reached correct answers despite generating inaccurate image descriptions, reflecting compensatory reasoning resilient to perceptual error. These findings show that aggregate accuracy scores conflate mechanistically distinct failure modes, and that perceptual and cognitive errors carry different implications for how MLLMs might be safely deployed or improved for diagnostic image interpretation. The expert-guided visual correction framework introduced here provides a generalizable, mechanism-based approach to benchmarking multimodal AI diagnostic performance that extends beyond periodontics to other visually driven diagnostic domains in medicine. As MLLMs become increasingly accessible to clinicians, residents, and dental educators, distinguishing perceptual from cognitive failure is essential for guiding responsible clinical use, targeting model refinement, and informing AI-augmented dental education and competency assessment.

Objectives: Collaboration among health care professionals and the services they provide can be strengthen by interprofessional education (IPE). IPE can be implemented at the undergraduate level. Accordingly, the objective of the present study was to evaluate senior students' understanding of the terms interdisciplinarity and multidisciplinarity within the context of IPE. Methods: A retrospective cross-sectional study design was used. Students understanding of interdisciplinarity and multidisciplinarity was assessed through an assessment question completed by three consecutive cohorts of senior undergraduate dental students at the UBC Faculty of Dentistry between 2021/22 and 2023/24 (N = 177). Responses had a maximum of 100 words and were categorized into one of four predetermined themes: concordant knowledge (when both definitions were correct), discordant rhetoric (when both definitions were incorrect), switched ideas (when the definitions were reversed), and altered discourse (when the concepts of discipline and specialty were conflated). Descriptive and inferential statistical analyses were performed using SPSS Version 31. Results: Of the 177 students enrolled, 164 provided responses to the question on multidisciplinarity and interdisciplinarity: 60 students in 2021/22, 51 students in 2022/23, and 53 students in 2023/24; the mean age was 25 years and 88 were female. Of the four predetermined themes, 45.7% of responses reflected concordant knowledge, 15.9% discordant rhetoric, 18.3% switched ideas, and 20.1% altered discourse. The logistic regression analysis showed age associated with a higher probability of providing the correct definitions (adjusted OR = 1.39; 95% CI: 1.06 - 1.83; p = 0.017). Conclusions: Knowledge of interdisciplinary and multidisciplinary appeared to be retained by the majority of students. However, dental education programs, alongside other health professional training programs, should continue to incorporate interprofessional education through both didactic and experiential learning opportunities to equip students with the skills necessary to provide collaborative care in future practice.

A dental AI system and a dentist reading the same radiographs form a paired comparison. Published comparative studies often report the two arms separately against a reference standard, leaving the joint pattern of correctness between them unavailable for secondary paired inference. We show what that omission costs. The accuracy difference remains exactly identified; its sampling variance does not, so the report contains the estimate and not its uncertainty. On a study of 282 units, two published accuracies are consistent with 38 distinct joint tables whose confidence intervals differ in width by a factor of 2.5. The consequence is a three-zone decision map rather than a single threshold: differences at or below 1.06 points are non-significant under every compatible table, differences at or above 6.03 points are significant under every compatible table, and in between the published numbers cannot decide. We then show the omission is repairable at negligible cost. One additional integer, the number of units both arms classify correctly, identifies the joint table exactly and restores standard paired inference. For a panel of readers the pairwise dependences must arise from one joint distribution, a constraint that binds once three readers are present; publishing each reader's joint-correct count against a single reference reader cannot widen and may tighten every pairwise bound, and in a 7-arm experiment reduced them by a median of 37% even for pairs excluding that reference. Where the integer was never published we give DentalPair-Cert, an interval with finite-sample coverage uniformly over every admissible within-unit AI-dentist dependence under the independent-sampling-unit model, certified in both the nuisance maximization and the inversion. Across 4,200,000 simulated comparisons an independence analysis falls to 74.5% coverage with 12.2% type-I error; in a purposive sample of 9 recent comparative studies, 1 reported a paired test on discordant units.

Background/Objectives. Autism spectrum disorder (ASD) has been associated with microbiome alterations, but the relative contribution of environmental and individual factors remains unclear. This study explored oral and gut microbiome profiles in environmentally matched dizygotic triplets discordant for ASD. Materials and Methods. Triplets in the 5-9 year age range, including one child with ASD and two neurotypical siblings, underwent standardized oral examination. Oral tongue-dorsum and rectal swab samples were analyzed by 16S rRNA sequencing. Taxonomic composition and beta diversity were evaluated descriptively. Results. Dominant bacterial phyla were broadly similar across siblings, but oral microbial profiles showed greater interindividual variation. The participant with ASD had the highest dental biofilm accumulation, predominance of Streptococcus, and reduced representation of several secondary genera. One neurotypical sibling with mild gingival inflammation showed greater representation of Fusobacterium, Prevotella, and Leptotrichia. Beta diversity demonstrated clearer interindividual separation among oral than gut samples. Conclusions. Individual-specific factors may influence microbiome patterns even under highly similar environmental and dietary conditions. These findings support further investigation of the oral microbiome as a complementary component of ASD microbiome research.

Implant-associated bone infection involves a complex interplay between pathogenic stimuli and host cell responses, yet analysis in preclinical models has typically relied on qualitative or semi-quantitative measures. We aimed to establish a quantified evaluation framework to define host-pathogen relationships in a preclinical implant infection model. Staphylococcus aureus-coated stainless-steel implants were inserted trans-cortically in mouse tibiae and bone changes recorded longitudinally by in vivo micro-CT. An automated segmentation task list was developed to independently isolate and quantify cortical, periosteal-reactive, and trabecular bone compartments. RGB trichrome histomorphometry was used to quantify bone matrix integrity, osteocyte lacunar geometry, and osteoclastic activity. Droplet digital PCR was used to determine absolute bacterial and host genome copy number. Infected implants produced marked reductions in trabecular bone volume fraction, number, and bone mineral density (BMD), together with decreased cortical bone volume fraction and increased cortical porosity, accompanied by significant elevations in periosteal bone volume fraction. Histologically, infected bone exhibited increased eroded surface indicative of osteoclastic resorption, extensive degraded bone matrix and pathological remodelling of osteocyte lacunae towards circularity, consistent with an osteocytic osteolysis response. Infection-induced changes to cortical bone structure correlated mostly with host cell rather than bacterial load; however, cortical BMD negatively correlated with the bacterial:host genome ratio. This multifaceted, quantified framework reveals distinct pathobiological effects of implant-associated infection on trabecular, cortical, and periosteal bone compartments, bone matrix and osteocyte and osteoclast populations, consistent with reports in human patients, suggesting that major pathological changes are driven by the host bone cell response to infection.

Seeking a simple vaccine to protect against all cancer-associated human papillomaviruses (HPV), L2 residues 17-36 of both HPV16 and HPV31 displayed on the surface of an Adeno-Associated Virus-Like Particle (AAVLP-HPV) was developed. Here, a phase 1 randomized, placebo-controlled, double-blind clinical study has been conducted in 20 male and female subjects at a single dose level (20 ug) without an adjuvant. AAVLP-HPV vaccine administration was safe and well tolerated. Repeat vaccination with AAVLP-HPV elicited L2-specific neutralizing antibodies of modest titer in serum. Antibodies cross-reactive with L2 of diverse HPV types were detected, but responses were weak in most vaccinees. We conclude that while AAVLP-HPV vaccination is well tolerated, an adjuvant is likely needed to consistently elicit durable and broadly neutralizing responses.

Rinsing-dependent dental hygiene presents a significant public health challenge in water-scarce environments. This study investigated combinations of xylitol (Xyl), chitosan (Chi), glycyrrhizin (Gly), epigallocatechin gallate (EGCG), dicalcium phosphate (DCP), and nano-hydroxyapatite (nHA) on the primary bacteria behind dental caries, S. mutans. These combinations were assessed for markers of dental caries by biofilm reduction, bacterial killing, and acid buffering against S. mutans when applied to an in vitro simulated enamel model using glass bead surfaces for biofilm formation, and gene expression was subsequently examined via RT-qPCR. Separately, mineral retention was also quantified. The EGCG-DCP-Xyl film demonstrated the highest overall efficacy, achieving a significant reduction in biofilm concentration compared to the untreated control and performing similarly in magnitude to the positive toothpaste control. Dead fluorescence staining confirmed that the EGCG-DCP-Xyl film induced the highest rate of non-viable cells, followed by the Chi-Gly film and the Gly-Xyl film. During 10-day pH cycling, the EGCG-DCP-Xyl and DCP-Xyl formulations buffered pH the most, consistently maintaining mean pH levels safely above the demineralization threshold of pH 5.5. The EGCG-DCP-Xyl also optimized mineral stability with the highest retained calcium concentration, significantly outperforming the Chi-Xyl film. At the transcript level, the EGCG-DCP-Xyl film induced substantial downregulation of key virulence genes, yielding decreases in expression for glucosyltransferase B (gtfB), associated with biofilm synthesis, collagen-binding protein (cnm), associated with tissue invasion, and lactate dehydrogenase (ldh), associated with lactic acid production, compared to the untreated control, with effects comparable in magnitude to the positive toothpaste control. This research suggests that targeting bacterial pathways and mineral loss through a portable film may have potential for preventing dental caries, especially in environments where water is limited. However, additional studies are necessary to evaluate real-world effectiveness.

Background: Early childhood caries remains one of the most prevalent and among the most neglected chronic diseases of childhood in low- and middle-income countries, and cariogenic feeding practices introduced in infancy are a principal, modifiable driver. National, spatially explicit estimates of such practices are lacking for Ghana, constraining geographically targeted interventions. Methods: We analyzed 3,007 children aged 6-23 months from the 2022 Ghana Demographic and Health Survey, linked to 600 georeferenced clusters. A composite cariogenic feeding index was built from bottle feeding, sugar-sweetened beverage consumption, and other cariogenic foods; a child was classified as exposed if any one component was present. Complex survey design was handled by Taylor series linearization. Determinants were examined using survey-weighted and two-level random-intercept logistic regression, and spatial clustering was assessed using global and local Morans I and Getis-Ord Gi* from a five-nearest-neighbour weights matrix. Results: Weighted national prevalence was 52.97% (95% confidence interval 50.19-55.75), ranging from 27.95% in the Savannah Region to 73.55% in the Western Region and patterned by residence (63.07% urban versus 43.90% rural) and wealth (32.87% in the poorest versus 74.45% in the richest quintile). Wealth and maternal education were the strongest multilevel correlates: the richest households showed roughly four times the odds of exposure relative to the poorest (adjusted odds ratio 4.00), and higher maternal education showed roughly two and a half times the odds relative to no education (adjusted odds ratio 2.51). The intraclass correlation coefficient was 0.219. Global Morans I was 0.231 (z = 9.73, p < 0.001), confirming significant positive spatial autocorrelation, with high-high clusters along the southern coastal belt (Western, Central, Greater Accra, Volta) and low-low clusters in the middle and northern belts (Bono, Ahafo, Upper West, Northern, North East). Conclusions: Cariogenic feeding among Ghanaian infants is common, socioeconomically patterned, and spatially clustered rather than random. Oral health promotion through routine growth monitoring and immunization platforms should be prioritized in the high-high clusters, while closing socioeconomic gradients would yield collateral benefit nationally. Trial registration: Not applicable. Keywords: cariogenic feeding, early childhood caries, infant and young child feeding, spatial analysis, Morans I, Getis-Ord Gi*, multilevel modeling, Ghana. Demographic and Health Survey; oral health epidemiology

Under homeostatic conditions, the cornea is avascular and contains few immune cells, but this changes rapidly following injury. Although the long-term consequences of corneal damage are well characterized, the earliest vascular and immune responses remain poorly understood. Here, we used a murine corneal alkali-burn model to examine limbal vascular activation and leukocyte recruitment immediately and at 2, 6, and 24 hours after injury. Limbal blood vessels underwent immediate dilation; however, vascular leakage into the corneal stroma occurred only in males. Lymphatic capillaries rapidly formed directed extensions toward the injury without significantly increasing their total vascular area, with males exhibiting longer extensions than females. Fluorescent dextran uptake provided evidence that these lymphatic vessels were functionally engaged in early tracer drainage. Despite pronounced vascular activation, early recruitment of neutrophils, monocytes, dendritic cells, macrophages, T cells, B cells, and natural killer cells remained limited. Thus, limbal blood and lymphatic vessels initiate the earliest response to corneal alkali injury before substantial leukocyte infiltration. These findings reveal sex-dependent differences in vascular permeability and lymphatic remodeling and identify the limbal vasculature as an early regulator of corneal inflammation and tissue repair.

Emerging evidence indicates that oral and systemic health are interconnected, yet the basis of this relationship remains incompletely understood. In a genome-wide association study of objectively measured dental caries in permanent dentition among Danish children and adolescents (DCCA) (N = 151,521), we identified 14 independent loci. Genes at DCCA-associated loci were enriched for expression in immune, secretory and epithelial cell populations. We found genetic correlations and evidence for shared causal variants with several cardiometabolic traits. Leveraging data from UK Biobank (Nmax = 501,936) and independent pediatric cohorts (Nmax = 3,412), we showed that genetic liability to DCCA associated with dentures, risk of coronary artery disease and type 2 diabetes in adults, and with HbA1C, lipid, liver enzyme levels, and plasma proteins implicated in oral, metabolic and hepatic biology in both populations. Our results provide new insights into the genetic architecture underlying the relationship between DCCA and cardiometabolic disease.

Streptococcus mutans is a key contributor to dental caries, with its capacity to form structured biofilm microcolonies being a principal component of its cariogenic potential. Yet, most mechanistic studies rely on a limited number of laboratory strains and may not capture the functional diversity present across the species. Here, we characterized a panel of phenotypically and genomically diverse S. mutans isolates to determine how strain background influences biofilm architecture, extracellular matrix accumulation, acid-associated physiology, environmental responsiveness, and antimicrobial susceptibility. Quantitative high-resolution imaging revealed extensive heterogeneity in produced biofilm microcolony size, structure, and matrix composition, demonstrating that biofilm architecture is not a uniform species-level trait. Interestingly, the commonly used reference strain UA159 displayed an intermediate phenotype related to microcolony size and biofilm organization. Human saliva further altered biofilm structure and matrix accumulation in a strain-dependent manner rather than producing a standard species-wide response. Isolates also differed in growth and retained biofilm biomass under acidic conditions, while acid accumulation within mature biofilms varied independently of average microcolony volume, demonstrating that strains that produce larger microcolonies on average were not necessarily associated with greater acid accumulation. Susceptibility to the antiseptics chlorhexidine and cetylpyridinium chloride likewise differed among isolates and could not be predicted from formed biofilm architecture alone. Together, these findings demonstrate that disease-relevant traits commonly attributed to S. mutans are distributed unevenly and only partially coupled across strain backgrounds, with biofilm spatial organization failing to serve as a dominant phenotype linking acid accumulation, acid tolerance, and antimicrobial susceptibility.

Background: Chronic inflammation is the most common histological feature in Benign Prostatic Hyperplasia (BPH), and T cells are a key component of immune infiltrate. Advanced BPH is commonly associated with the formation of nodules, but it remains unclear whether a link exists among T cell infiltration, nodular development, and BPH progression. Using a Toxoplasma gondii (T. gondii) model and human specimens, we characterize the subtypes of T cells present during prostatic hyperplasia and their association with nodular development of the prostate. Methods: Male CBA/j mice were intraperitoneally infected with T. gondii parasites, and flow cytometry was performed on the prostate to quantify the number of CD4+ and CD8+ T cells. Histology was used to score microglandular hyperplasia (MGH), and immunofluorescence was used to quantify and examine the locality of CD4+ and CD8+ T cells and compared that to human BPH tissue. Results: We found that infecting male mice with T. gondii resulted in an increase of both CD4+ and CD8+ T cells in the prostate acutely and that CD8+ cells remained sustained at chronically. We also established the presence of glandular nodule formation at this timepoint through hematoxylin and eosin (H&E) staining. Immunofluorescence revealed that CD8+ cells were found proximal to forming glandular nodules relative to non-nodular glands. We also found more CD8+ cells localized to non-nodular glands in nodular BPH tissue versus non-nodular BPH tissue. Finally, we discovered a higher prevalence of CD8+ cells in T. gondii IgG+ patients than in IgG- patients. All T. gondii IgG+ patients exhibited nodular BPH, whereas all but one IgG- patient exhibited non-nodular BPH. Conclusions: This study is the first to investigate the presence and location of CD4+ and CD8+ T cells within nodular and non-nodular BPH glands. We found an association of the presence of CD8+ T cells with nodular progression. This association held true in human prostate tissue. Translationally, CD8+ T cells may enhance nodular BPH progression, and T. gondii infection may promote this CD8+ T cell-mediated response.

Current approaches for imaging fibrotic remodeling have sensitivity, specificity and cost drawbacks that limit both preclinical research and clinical diagnosis. Here, we show that fast green FCF, a small molecule that binds to fibrillar collagen, enables highly sensitive and specific imaging of fibrosis in lung samples from mice and humans using fluorescence microscopy. We report strategies for using fast green FCF staining to assess fibrotic remodeling using precision-cut lung slice and whole-biopsy preparations. Our findings demonstrate that fluorescence imaging of fast green FCF-stained collagen will be useful for fibrosis research and may help to improve detection of fibrosis in clinical pathology.

S. mutans and V. parvula cooperate in dental plaque to assemble a healthy biofilm and are associated with increased caries risk. S. mutans produces lactic acid from carbohydrates resulting in a final biofilm pH[~]4, while V. parvula metabolizes lactate to acetic and propionic acids resulting in pH[~]5. This process results in healthier biofilms that still generate a pH capable of demineralizing tooth surfaces (pH<5.5). The purpose of this study was to identify V. parvula genes required for deacidification of S. mutans biofilms and determine whether the ability of V. parvula to deacidify S. mutans biofilms correlates with enhanced biofilm health. Using transposon mutagenesis in V. parvula we identified several genes required for deacidification of S. mutans biofilms. These included numerous V. parvula transposon mutations in the previously unstudied lutABC lactate utilization operon. To assess biofilm health, S. mutans in the presence of various V. parvula mutants were stained with a LIVE/DEAD stain and imaged by fluorescence microscopy. An intact lutABC operon was required to enhance biofilm health, as demonstrated by plasmid-based complementation of a lutB transposon mutant. Transposon insertions in other loci unrelated to deacidification had no impact on biofilm health. Addition of HEPES buffer at the time of S. mutans biofilm assembly prevented full acidification of the biofilm and resulted in improved biofilm health, even without the addition of V. parvula. Finally, we found V. parvula can use either nitrate or fumarate as a final ETC electron acceptor during lactate utilization. In all, we found the lutABC lactate utilization operon of V. parvula is critical for the ability of V. parvula to deacidify S. mutans biofilms and promote biofilm health. Interfering with this pathway would interrupt the mutually beneficial relationship between S. mutans and V. parvula that leads to their co-association in caries, root caries, and early childhood caries.