diff --git a/system/database/drivers/mssql/mssql_forge.php b/system/database/drivers/mssql/mssql_forge.php
index 4d98221..3a3528f 100644
--- a/system/database/drivers/mssql/mssql_forge.php
+++ b/system/database/drivers/mssql/mssql_forge.php
@@ -103,7 +103,7 @@
 
 		if (count($primary_keys) > 0)
 		{
-			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->protect_identifiers($primary_keys)).')';
+			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $this->db->escape_identifiers($primary_keys)).')';
 		}
 
 		if (is_array($keys) && count($keys) > 0)
@@ -111,7 +111,7 @@
 			foreach ($keys as $key)
 			{
 				$key = is_array($key)
-					? $this->db->protect_identifiers($key)
+					? $this->db->escape_identifiers($key)
 					: array($this->db->escape_identifiers($key));
 
 				$sql .= ",\n\tFOREIGN KEY (".implode(', ', $key).')';