diff --git a/src/assets/model-instance-rendering.ts b/src/assets/model-instance-rendering.ts
index b8efe110..1b003cc3 100644
--- a/src/assets/model-instance-rendering.ts
+++ b/src/assets/model-instance-rendering.ts
@@ -88,11 +88,17 @@ function applyWireframeMaterialPresentation(group: Group) {
     }
 
     if (Array.isArray(maybeMesh.material)) {
-      maybeMesh.material = maybeMesh.material.map((material) => createWireframeMaterial(material));
+      const originalMaterials = maybeMesh.material;
+      maybeMesh.material = originalMaterials.map((material) => createWireframeMaterial(material));
+      for (const material of originalMaterials) {
+        material.dispose();
+      }
       return;
     }
 
-    maybeMesh.material = createWireframeMaterial(maybeMesh.material);
+    const originalMaterial = maybeMesh.material;
+    maybeMesh.material = createWireframeMaterial(originalMaterial);
+    originalMaterial.dispose();
   });
 }
 
diff --git a/src/viewport-three/viewport-host.ts b/src/viewport-three/viewport-host.ts
index 2de1d3bf..8bc4a090 100644
--- a/src/viewport-three/viewport-host.ts
+++ b/src/viewport-three/viewport-host.ts
@@ -719,11 +719,17 @@ export class ViewportHost {
       }
 
       if (Array.isArray(maybeMesh.material)) {
-        maybeMesh.material = maybeMesh.material.map((material) => this.createWireframeDisplayMaterial(material));
+        const originalMaterials = maybeMesh.material;
+        maybeMesh.material = originalMaterials.map((material) => this.createWireframeDisplayMaterial(material));
+        for (const material of originalMaterials) {
+          material.dispose();
+        }
         return;
       }
 
-      maybeMesh.material = this.createWireframeDisplayMaterial(maybeMesh.material);
+      const originalMaterial = maybeMesh.material;
+      maybeMesh.material = this.createWireframeDisplayMaterial(originalMaterial);
+      originalMaterial.dispose();
     });
   }