diff --git a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Bounded_normal_change_placement.h b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Bounded_normal_change_placement.h
index 71193952207..3699038ebda 100644
--- a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Bounded_normal_change_placement.h
+++ b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Bounded_normal_change_placement.h
@@ -43,7 +43,7 @@ Returns the placement computed by `place`, if no
 triangle in the profile changes the normal by more than 90 degree.
 */ 
 template <typename Profile>
-optional<typename Profile::Point> 
+boost::optional<typename Profile::Point>
 operator()(const Profile& profile) const; 
 
 /// @}
diff --git a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h
index 20b0ef685eb..4e8db2bb8e3 100644
--- a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h
+++ b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h
@@ -38,8 +38,8 @@ The `placement` argument is ignored.
 
 */
 template <typename Profile, typename T>
-optional<typename Profile::FT> operator()(const Profile& profile,
-                                          const T& placement) const;
+boost::optional<typename Profile::FT> operator()(const Profile& profile,
+                                                 const T& placement) const;
 
 /// @}
 
diff --git a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h
index 72f724a93f7..e8209b32039 100644
--- a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h
+++ b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h
@@ -37,7 +37,7 @@ Returns the cost of collapsing the edge (represented by its profile) considering
 the new `placement` computed for it.
 */
 template <typename Profile>
-optional<typename Profile::FT>
+boost::optional<typename Profile::FT>
 operator()(const Profile& profile,
            const boost::optional<typename Profile::Point>& placement) const
 
diff --git a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h
index a714378f826..ac0c9466756 100644
--- a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h
+++ b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h
@@ -39,7 +39,7 @@ Returns the new position for the remaining vertex after collapsing the edge
 (represented by its profile).
 */
 template <typename Profile>
-optional<typename Profile::Point>
+boost::optional<typename Profile::Point>
 operator()(const Profile& profile) const;
 
 /// @}
diff --git a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h
index be4baa1fd3f..faaafe5d221 100644
--- a/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h
+++ b/Surface_mesh_simplification/doc/Surface_mesh_simplification/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h
@@ -36,7 +36,7 @@ the points of the source and target vertices
 (`profile.p0()` and `profile.p1()`) 
 */ 
 template <typename Profile>
-optional<typename Profile::Point> 
+boost::optional<typename Profile::Point>
 operator()(const Profile& profile) const; 
 
 /// @}
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Edge_collapse_visitor_base.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Edge_collapse_visitor_base.h
index ad6a367b29d..66df504c40d 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Edge_collapse_visitor_base.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Edge_collapse_visitor_base.h
@@ -22,7 +22,7 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
 
 namespace CGAL {
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Constrained_placement.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Constrained_placement.h
index e09835e3677..4685d7565e8 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Constrained_placement.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Constrained_placement.h
@@ -22,7 +22,7 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
 
 namespace CGAL {
@@ -42,7 +42,7 @@ public:
   {}
 
   template <typename Profile> 
-  optional<typename Profile::Point> operator()(const Profile& aProfile) const
+  boost::optional<typename Profile::Point> operator()(const Profile& aProfile) const
   {
     typedef typename Profile::TM                                    TM;
     typedef typename boost::graph_traits<TM>::halfedge_descriptor   halfedge_descriptor;
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_ratio_stop_predicate.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_ratio_stop_predicate.h
index 6188583ed32..e5c174d15af 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_ratio_stop_predicate.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_ratio_stop_predicate.h
@@ -22,7 +22,7 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
 
 namespace CGAL {
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_stop_predicate.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_stop_predicate.h
index 4100d9a6c76..525126d242a 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_stop_predicate.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Count_stop_predicate.h
@@ -22,7 +22,7 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
 
 namespace CGAL {
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h
index 2f8772d176c..e50dab45e7f 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_length_cost.h
@@ -22,7 +22,7 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
 
 namespace CGAL {
@@ -36,9 +36,9 @@ public:
   Edge_length_cost() {}
 
   template <typename Profile, typename T>
-  optional<typename Profile::FT> operator()(const Profile& aProfile, const T& /*aPlacement*/) const
+  boost::optional<typename Profile::FT> operator()(const Profile& aProfile, const T& /*aPlacement*/) const
   {
-    typedef optional<typename Profile::FT> result_type;
+    typedef boost::optional<typename Profile::FT>                     result_type;
     return result_type(squared_distance(aProfile.p0(), aProfile.p1()));
   }
 };
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h
index e26606ca668..c06ef1e1f86 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h
@@ -22,7 +22,7 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 
 #include <vector>
 #include <set>
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h
index 3e70fb5e9e4..9d39e7d55b6 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_cost.h
@@ -22,8 +22,8 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
-#include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Detail/Lindstrom_Turk_core.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
+#include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/internal/Lindstrom_Turk_core.h>
 
 namespace CGAL {
 namespace Surface_mesh_simplification {
@@ -39,11 +39,11 @@ public:
   {}
 
   template <typename Profile>
-  optional<typename Profile::FT>
+  boost::optional<typename Profile::FT>
   operator()(const Profile& aProfile,
-             const optional<typename Profile::Point>& aPlacement) const
+             const boost::optional<typename Profile::Point>& aPlacement) const
   {
-    return LindstromTurkCore<TM,Profile>(mParams,aProfile).compute_cost(aPlacement);
+    return internal::LindstromTurkCore<TM,Profile>(mParams,aProfile).compute_cost(aPlacement);
   }
 
 private:
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h
index 5d1dcf9de58..a285c793830 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_placement.h
@@ -22,8 +22,8 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
-#include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Detail/Lindstrom_Turk_core.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
+#include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/internal/Lindstrom_Turk_core.h>
 
 namespace CGAL {
 namespace Surface_mesh_simplification {
@@ -39,9 +39,9 @@ public:
   {}
 
   template <typename Profile>
-  optional<typename Profile::Point> operator()(const Profile& aProfile) const
+  boost::optional<typename Profile::Point> operator()(const Profile& aProfile) const
   {
-    return LindstromTurkCore<TM,Profile>(mParams,aProfile).compute_placement();
+    return internal::LindstromTurkCore<TM,Profile>(mParams, aProfile).compute_placement();
   }
 
 private:
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h
index e998c99fa64..81b59cf1edd 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Midpoint_placement.h
@@ -23,7 +23,7 @@
 #include <CGAL/license/Surface_mesh_simplification.h>
 
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
 
 namespace CGAL {
@@ -38,9 +38,9 @@ public:
   Midpoint_placement() {}
 
   template <typename Profile>
-  optional<typename Profile::Point> operator()(const Profile& aProfile) const
+  boost::optional<typename Profile::Point> operator()(const Profile& aProfile) const
   {
-    return optional<typename Profile::Point>(midpoint(aProfile.p0(), aProfile.p1()));
+    return boost::optional<typename Profile::Point>(midpoint(aProfile.p0(), aProfile.p1()));
   }
 };
 
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Detail/Lindstrom_Turk_core.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/internal/Lindstrom_Turk_core.h
similarity index 97%
rename from Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Detail/Lindstrom_Turk_core.h
rename to Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/internal/Lindstrom_Turk_core.h
index 70bdee2cbad..35eaae9d62b 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Detail/Lindstrom_Turk_core.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Policies/Edge_collapse/internal/Lindstrom_Turk_core.h
@@ -22,12 +22,13 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Cartesian_converter.h>
-
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk_params.h>
 
+#include <CGAL/Cartesian_converter.h>
+#include <CGAL/Cartesian/MatrixC33.h>
+
 #include <limits>
 #include <vector>
 
@@ -40,6 +41,7 @@
 
 namespace CGAL {
 namespace Surface_mesh_simplification {
+namespace internal {
 
 template<class TM_, class Profile_>
 class LindstromTurkCore
@@ -65,9 +67,9 @@ public:
   typedef typename Kernel::Vector_3                                      Vector;
   typedef typename Kernel::FT                                            FT;
 
-  typedef optional<FT>                                                   Optional_FT;
-  typedef optional<Point>                                                Optional_point;
-  typedef optional<Vector>                                               Optional_vector;
+  typedef boost::optional<FT>                                            Optional_FT;
+  typedef boost::optional<Point>                                         Optional_point;
+  typedef boost::optional<Vector>                                        Optional_vector;
 
   typedef MatrixC33<Kernel>                                              Matrix;
 
@@ -158,7 +160,7 @@ private :
   static bool is_finite(const Matrix& m) { return is_finite(m.r0()) && is_finite(m.r1()) && is_finite(m.r2()); }
 
   template<class T>
-  static optional<T> filter_infinity(const T& n) { return is_finite(n) ? optional<T>(n) : optional<T>(); }
+  static boost::optional<T> filter_infinity(const T& n) { return is_finite(n) ? boost::optional<T>(n) : boost::optional<T>(); }
 
   TM& surface() const { return mProfile.surface(); }
 
@@ -307,7 +309,7 @@ compute_placement()
   if(mConstraints_n == 3)
   {
     // If the matrix is singular it's inverse cannot be computed so an 'absent' value is returned.
-    optional<Matrix> lOptional_Ai = inverse_matrix(mConstraints_A);
+    boost::optional<Matrix> lOptional_Ai = inverse_matrix(mConstraints_A);
     if(lOptional_Ai)
     {
       const Matrix& lAi = *lOptional_Ai;
@@ -748,6 +750,7 @@ add_constraint_from_gradient(const Matrix& H,
   }
 }
 
+} // namespace internal
 } // namespace Surface_mesh_simplification
 } // namespace CGAL
 
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/edge_collapse.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/edge_collapse.h
index 95d72bde349..dfa9980175c 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/edge_collapse.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/edge_collapse.h
@@ -25,8 +25,8 @@
 #include <CGAL/boost/graph/properties.h>
 #include <CGAL/boost/graph/named_function_params.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Edge_collapse.h>
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Edge_collapse.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/LindstromTurk.h>
 
 namespace CGAL {
@@ -97,10 +97,10 @@ int edge_collapse(TM& aSurface,
   internal_np::graph_visitor_t vis = internal_np::graph_visitor_t();
 
   return edge_collapse(aSurface, aShould_stop,
-                       choose_const_pmap(get_param(aParams,internal_np::vertex_index),aSurface,boost::vertex_index),
-                       choose_pmap(get_param(aParams,internal_np::vertex_point),aSurface,boost::vertex_point),
-                       choose_const_pmap(get_param(aParams,internal_np::halfedge_index),aSurface,boost::halfedge_index),
-                       choose_param(get_param(aParams,internal_np::edge_is_constrained),No_constrained_edge_map<TM>()),
+                       choose_const_pmap(get_param(aParams,internal_np::vertex_index), aSurface, boost::vertex_index),
+                       choose_pmap(get_param(aParams,internal_np::vertex_point), aSurface, boost::vertex_point),
+                       choose_const_pmap(get_param(aParams,internal_np::halfedge_index), aSurface, boost::halfedge_index),
+                       choose_param(get_param(aParams,internal_np::edge_is_constrained), No_constrained_edge_map<TM>()),
                        choose_param(get_param(aParams,internal_np::get_cost_policy), LindstromTurk_cost<TM>()),
                        choose_param(get_param(aParams,internal_np::get_placement_policy), LindstromTurk_placement<TM>()),
                        choose_param(get_param(aParams,vis), Dummy_visitor()));
@@ -131,7 +131,7 @@ int edge_collapse(TM& aSurface,
 template<class TM, class ShouldStop>
 int edge_collapse(TM& aSurface, const ShouldStop& aShould_stop)
 {
-  return edge_collapse(aSurface,aShould_stop, CGAL::parameters::halfedge_index_map(get(boost::halfedge_index,aSurface)));
+  return edge_collapse(aSurface, aShould_stop, CGAL::parameters::halfedge_index_map(get(boost::halfedge_index, aSurface)));
 }
 
 template<class TM, class ShouldStop, class GT>
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Detail/Common.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/internal/Common.h
similarity index 88%
rename from Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Detail/Common.h
rename to Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/internal/Common.h
index b80589a8dcf..8814f921a4f 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Detail/Common.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/internal/Common.h
@@ -23,20 +23,14 @@
 #include <CGAL/license/Surface_mesh_simplification.h>
 
 #include <CGAL/algorithm.h>
-#include <CGAL/Cartesian/MatrixC33.h>
-#include <CGAL/Modifiable_priority_queue.h>
 #include <CGAL/boost/graph/properties.h>
 #include <CGAL/boost/graph/iterator.h>
 
 #include <boost/config.hpp>
-#include <boost/shared_ptr.hpp>
-#include <boost/scoped_ptr.hpp>
 #include <boost/iterator_adaptors.hpp>
 #include <boost/optional/optional.hpp>
-#include <boost/none.hpp>
 #include <boost/tuple/tuple.hpp>
 #include <boost/format.hpp>
-#include <boost/scoped_array.hpp>
 #include <boost/graph/graph_traits.hpp>
 #include <boost/graph/properties.hpp>
 #include <boost/graph/adjacency_list.hpp>
@@ -50,24 +44,6 @@
 namespace CGAL {
 namespace Surface_mesh_simplification {
 
-using boost::num_edges;
-using boost::num_vertices;
-using boost::edges;
-using boost::out_edges;
-using boost::in_edges;
-using boost::source;
-using boost::target;
-
-using boost::shared_ptr;
-using boost::optional;
-using boost::none;
-using boost::put_get_helper;
-using boost::get;
-using boost::put;
-using boost::addressof;
-
-using namespace boost::tuples;
-
 template<class Handle>
 inline bool handle_assigned(Handle h) { Handle null; return h != null; }
 
@@ -167,4 +143,4 @@ inline std::string optional_to_string(const boost::optional<T>& o) {
   #define CGAL_SURF_SIMPL_TEST_assertion_code(CODE)
 #endif
 
-#endif // CGAL_SURFACE_MESH_SIMPLIFICATION_DETAIL_COMMON_H //
+#endif // CGAL_SURFACE_MESH_SIMPLIFICATION_DETAIL_COMMON_H
diff --git a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Detail/Edge_collapse.h b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/internal/Edge_collapse.h
similarity index 98%
rename from Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Detail/Edge_collapse.h
rename to Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/internal/Edge_collapse.h
index 0f20f23c1c5..c638f262539 100644
--- a/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/Detail/Edge_collapse.h
+++ b/Surface_mesh_simplification/include/CGAL/Surface_mesh_simplification/internal/Edge_collapse.h
@@ -22,10 +22,14 @@
 
 #include <CGAL/license/Surface_mesh_simplification.h>
 
-#include <CGAL/Surface_mesh_simplification/Detail/Common.h>
+#include <CGAL/Surface_mesh_simplification/internal/Common.h>
 #include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_profile.h>
+
 #include <CGAL/boost/graph/Euler_operations.h>
 #include <CGAL/boost/graph/helpers.h>
+#include <CGAL/Modifiable_priority_queue.h>
+
+#include <boost/scoped_array.hpp>
 
 namespace CGAL {
 namespace Surface_mesh_simplification {
@@ -79,8 +83,8 @@ public:
   typedef typename Traits::Vector_3                                       Vector;
   typedef typename Traits::FT                                             FT;
 
-  typedef optional<FT>                                                    Cost_type;
-  typedef optional<Point>                                                 Placement_type;
+  typedef boost::optional<FT>                                             Cost_type;
+  typedef boost::optional<Point>                                          Placement_type;
 
   struct Compare_id
   {
@@ -101,7 +105,7 @@ public:
 
     bool operator()(const halfedge_descriptor& a, const halfedge_descriptor& b) const
     {
-      // NOTE: A cost is an optional<> value.
+      // NOTE: A cost is a boost::optional<> value.
       // Absent optionals are ordered first; that is, "none < T" and "T > none" for any defined T != none.
       // In consequence, edges with undefined costs will be promoted to the top of the priority queue and poped out first.
       return mAlgorithm->get_data(a).cost() < mAlgorithm->get_data(b).cost();
@@ -293,9 +297,9 @@ private:
     CGAL_SURF_SIMPL_TEST_assertion(!mPQ->contains(aEdge));
   }
 
-  optional<halfedge_descriptor> pop_from_PQ()
+  boost::optional<halfedge_descriptor> pop_from_PQ()
   {
-    optional<halfedge_descriptor> rEdge = mPQ->extract_top();
+    boost::optional<halfedge_descriptor> rEdge = mPQ->extract_top();
     if(rEdge)
     {
       CGAL_SURF_SIMPL_TEST_assertion(is_primary_edge(*rEdge));
@@ -564,7 +568,7 @@ loop()
 
   // Pops and processes each edge from the PQ
 
-  optional<halfedge_descriptor> lEdge;
+  boost::optional<halfedge_descriptor> lEdge;
 #ifdef CGAL_SURF_SIMPL_INTERMEDIATE_STEPS_PRINTING
   int i_rm=0;
 #endif
diff --git a/Surface_mesh_simplification/test/Surface_mesh_simplification/test_edge_collapse_Polyhedron_3.cpp b/Surface_mesh_simplification/test/Surface_mesh_simplification/test_edge_collapse_Polyhedron_3.cpp
index 7bf9d392d3f..5d207ae9201 100644
--- a/Surface_mesh_simplification/test/Surface_mesh_simplification/test_edge_collapse_Polyhedron_3.cpp
+++ b/Surface_mesh_simplification/test/Surface_mesh_simplification/test_edge_collapse_Polyhedron_3.cpp
@@ -26,6 +26,8 @@
 #include "basics.h"
 #include "test_self_intersection.h"
 
+#include <boost/shared_ptr.hpp>
+
 //#define TEST_TEST_TRACE_ENABLED
 
 template<std::size_t N> struct eat_sizeof {};