diff --git a/Kernel_23/include/CGAL/Kernel/function_objects.h b/Kernel_23/include/CGAL/Kernel/function_objects.h
index d7a649bb832..ceddc423b2a 100644
--- a/Kernel_23/include/CGAL/Kernel/function_objects.h
+++ b/Kernel_23/include/CGAL/Kernel/function_objects.h
@@ -1837,7 +1837,7 @@ namespace CommonKernelFunctors {
   };
 
   template <typename K>
-  class Construct_vertex_3
+  class Construct_vertex_3 : Has_qrt
   {
     typedef typename K::Point_3          Point_3;
     typedef typename K::Segment_3        Segment_3;
@@ -2712,6 +2712,11 @@ namespace CommonKernelFunctors {
 
 } // namespace CommonKernelFunctors
 
+  template <class K>
+  struct Qualified_result_of<CommonKernelFunctors::Construct_vertex_3<K>,Iso_cuboid_3<K> > :
+    qrt_or_not<typename CommonKernelFunctors::Construct_vertex_3<K>,false>
+  {};
+
 } //namespace CGAL
 
 #endif // CGAL_KERNEL_FUNCTION_OBJECTS_H
diff --git a/Kernel_23/include/CGAL/Triangle_3.h b/Kernel_23/include/CGAL/Triangle_3.h
index 5d994b53fbf..7ab023c0264 100644
--- a/Kernel_23/include/CGAL/Triangle_3.h
+++ b/Kernel_23/include/CGAL/Triangle_3.h
@@ -88,12 +88,15 @@ public:
     return R().has_on_3_object()(*this, p);
   }
 
-  Point_3 vertex(int i) const // TODO : use Qrt
+
+  typename Qualified_result_of<typename R::Construct_vertex_3, Triangle_3 >::type
+  vertex(int i) const
   {
     return R().construct_vertex_3_object()(*this, i);
   }
 
-  Point_3 operator[](int i) const // TODO : use Qrt
+  typename Qualified_result_of<typename R::Construct_vertex_3, Triangle_3 >::type
+  operator[](int i) const
   {
     return vertex(i);
   }