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1. Dental Fluctuating Asymmetry: Environmental Factors Influencing Cayo Santiago Rhesus Macaque ( Macaca mulatta ) Dental Development

   https://doi.org/10.1002/ajp.70085  

   Kohn, Luci; Schulz, Kurt; Kensler, Terry B; Maldonado, Elizabeth; Guatelli‐Steinberg, Debbie; Zhao, Martin Q; Francis, George; Wang, Qian (November 2025, American Journal of Primatology)

   ABSTRACT Increased fluctuating asymmetry, or random differences between right and left sides, has been associated with developmental stress or developmental instability. This study examines fluctuating asymmetry (FA) of mesio‐distal and bucco‐lingual dimensions of deciduous maxillary molars (m¹, m²), and permanent maxillary premolars and molars (P³, P⁴, M¹, M²) of 466 rhesus macaques (Macaca mulatta) born between 1950 and 2018 from Cayo Santiago (CS), Puerto Rico. All included individuals were of known age, sex, birth year, and matriline. We assess whether a secular trend occurs in FA over a 68‐year period, sex differences in FA, and whether environmental or management factors in the colony history resulted in decreased FA. Regression of FA on birth year tested for a secular trend in FA. A mixed‐model two‐way analysis of variance was used to test for the influence of food supplementation, tetanus vaccination and hurricane experience during dental development on FA. Differences across matrilines in response to the management or environmental factors were tested by ANOVA. There was no significant secular trend in FA. There was limited reduction of FA with implementation of the high protein diet, and limited support for the decreased FA associated with the implementation of tetanus vaccination. There is also limited difference in dental FA associated with exposure to a hurricane during dental development. Matrilineal differences in FA were observed for several teeth. The free‐ranging environment of Cayo Santiago is a complex environment, with many factors influencing the development of young rhesus macaques. While the introduction of a high protein diet or the implementation of a tetanus vaccination program may have improved individual health overall, there are likely other factors that may cause developmental stress and result in dental FA. 

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2. Optical imaging of dental plaque pH

   Chuqin Huang, Manuja Sharma (April 2020, SPIE Medical Imaging 2020: Image-Guided Procedures, Robotic Interventions, and Modeling)

   Tooth decay is one of the most common chronic infectious diseases worldwide. Bacteria from the oral biofilm create a local acidic environment that demineralizes the enamel in the caries disease process. By optically imaging plaque pH in pits and fissures and contacting surfaces of teeth, then medicinal therapies can be accurately applied to prevent or monitor the reversal of caries. To achieve this goal, the fluorescence emission from an aqueous solution of sodium fluorescein was measured using a multimodal scanning fiber endoscope (mmSFE). The 1.6-millimeter diameter mmSFE scans 424nm laser light and collects wide-field reflectance for navigational purposes in grayscale at 30 Hz. Two fluorescence channels centered at 520 and 549 nm are acquired and ratiometric analysis produces a pseudo-color overlay of pH. In vitro measurements calibrate the pH heat maps in the range 4.7 to 7.2 pH (0.2 standard deviation). In vivo measurements of a single case study provides informative images of interproximal biofilm before and after a sugar rinse. Post processing a time series of images provides a method that calculates the average pH changes of oral biofilm, replicating the Stephan Curve. These spatio-temporal records of oral biofilm pH can provide a new method of assessing the risk of tooth decay, guide the application of preventative therapies, and provide a quantitative monitor of overall oral health. The non-contact in vivo optical imaging of pH may be extended to measurements of wound healing, tumor environment, and other food processing surfaces since it relies on low power laser light and a US FDA approved dye. 

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3. Evolutionary implications of dental anomalies in bats

   https://doi.org/10.1111/evo.14211  

   Esquivel, Diego A.; Maestri, Renan; Santana, Sharlene E. (May 2021, Evolution)

   null (Ed.)
4. Beyond Description: The Many Facets of Dental Biomechanics

   https://doi.org/10.1093/icb/icaa103  

   Crofts, S B; Smith, S M; Anderson, P S (July 2020, Integrative and Comparative Biology)

   Synopsis Teeth lie at the interface between an animal and its environment and, with some exceptions, act as a major component of resource procurement through food acquisition and processing. Therefore, the shape of a tooth is closely tied to the type of food being eaten. This tight relationship is of use to biologists describing the natural history of species and given the high instance of tooth preservation in the fossil record, is especially useful for paleontologists. However, correlating gross tooth morphology to diet is only part of the story, and much more can be learned through the study of dental biomechanics. We can explore the mechanics of how teeth work, how different shapes evolved, and the underlying forces that constrain tooth shape. This review aims to provide an overview of the research on dental biomechanics, in both mammalian and non-mammalian teeth, and to synthesize two main approaches to dental biomechanics to develop an integrative framework for classifying and evaluating dental functional morphology. This framework relates food material properties to the dynamics of food processing, in particular how teeth transfer energy to food items, and how these mechanical considerations may have shaped the evolution of tooth morphology. We also review advances in technology and new techniques that have allowed more in-depth studies of tooth form and function. 

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5. Bioinspired antibacterial surface for orthopedic and dental implants

   https://doi.org/10.1002/jbm.b.34762  

   Elliott, Drew T.; Wiggins, Russell J.; Dua, Rupak (November 2020, Journal of Biomedical Materials Research Part B: Applied Biomaterials)

   Abstract Bacterial infections still present a significant concern in orthopedic and dental implant failure. Previous investigations have focused on modifying the surface texture, roughness, or coating implants with antibiotics to provide enhanced anti‐bacterial properties. However, they have demonstrated limited success. In this study, we attempted to engineer the titanium (Ti) alloy surface biomimetically at the nano level using alkaline hydrothermal treatment (AHT) inspired by cicada's wing structure. Two modified surfaces of Ti plates were developed using 4 and 8‐hr AHT at 230°C. We found that the control plates showed a relatively smooth surface, with little artifacts on the surface. In contrast, 4‐hr AHT and 8‐hr AHT plates showed nano‐spikes of heights around 250–350 and 100–1,250 nm, respectively, that were distributed randomly all over the surface. We found a statistically significant (p < 0.05) number of non‐viable cells for bothS. aureusandP. aeruginosabacterial strains when incubated for 1 hr in a dynamic environment when compared with the control group. The 8‐hr AHT groups killed 38.97% moreS. aureusin static culture and 11.27% in a dynamic environment than the 4‐hr AHT. Overall, the findings indicate that the nanostructures generated on titanium by the AHT showed significant bactericidal properties. We, therefore, recommend conducting alkaline hydrothermal treatment on the surfaces for future orthopedic and dental metallic implants. 

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