diff --git a/src/lib/bind/accessors.html b/src/lib/bind/accessors.html
index 6c286d57bc..594902a409 100644
--- a/src/lib/bind/accessors.html
+++ b/src/lib/bind/accessors.html
@@ -86,7 +86,7 @@
 
       _clearPath: function(path) {
         for (var prop in this.__data__) {
-          if (prop.indexOf(path + '.') === 0) {
+          if (Polymer.Path.isDescendant(path, prop)) {
             this.__data__[prop] = undefined;
           }
         }
diff --git a/src/standard/notify-path.html b/src/standard/notify-path.html
index d2b1f8d87a..3b9ac87e71 100644
--- a/src/standard/notify-path.html
+++ b/src/standard/notify-path.html
@@ -360,9 +360,9 @@
       _notifyBoundPaths: function(path, value) {
         for (var a in this._boundPaths) {
           var b = this._boundPaths[a];
-          if (path.indexOf(a + '.') == 0) {
+          if (Path.isDescendant(a, path)) {
             this._notifyPath(Path.translate(a, b, path), value);
-          } else if (path.indexOf(b + '.') == 0) {
+          } else if (Path.isDescendant(b, path)) {
             this._notifyPath(Path.translate(b, a, path), value);
           }
         }