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How did ornithischian beaks and teeth help them eat plants?

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Illustration showing various dinosaur species drawn to scale and grouped by geologic era: Late Cretaceous, Early Cretaceous, Jurassic, and Triassic. Dinosaurs range from large species like Brachiosaurus and Tyrannosaurus to smaller ones like Velociraptor and Compsognathus, with a human silhouette included for size comparison. Measurement bars at the bottom indicate 1 meter and 3 feet for scale reference. — dinosaur A selection of dinosaurs grouped by the geologic interval in which they lived.

Ornithischian dinosaurs were highly specialized herbivores that utilized a combination of horny beaks and complex dental structures to process tough, fibrous plant material.12

Horny Beaks: Most ornithischians possessed a toothless, horny beak—often supported by a unique bone called the predentary—which was ideal for cropping, nipping, or stripping leaves and needles from vegetation.342
Cheek Teeth and Grinding: Behind the beak, these dinosaurs featured specialized cheek teeth. In many species, these teeth were set inward from the outer cheek surface, suggesting the presence of cheeks that held food in the mouth for further processing.4
Advanced Dental Batteries: Advanced groups, such as hadrosaurs and ceratopsians, evolved "dental batteries"—rows of tightly packed teeth that formed efficient grinding or shearing surfaces. These teeth often featured self-sharpening mechanisms where enamel wore down unevenly, maintaining a sharp edge for crushing tough plant matter.3142
Jaw Mechanics: The jaw joint was positioned below the plane where the teeth met, allowing for more effective occlusion and grinding of cellulose-heavy diets.42