Three koalas (Phascolarctos cinereus) presented with moderate to severe interproximal space accumulation with Eucalyptus spp. at the San Diego Zoo. Premise™ trimodal composite was used to create dental onlay bridge-like prostheses to eliminate open, enlarged interproximal spaces. The prostheses prevented further leaf material accumulation within the interproximal spaces and consequently reduced periodontal disease. Aesthetically, the prosthesis replicates normal tooth coloration and appearance and wears at a similar rate to surrounding teeth. Prosthetic repair or replacement may be required, so periodic examination every 3–6 mo is recommended.