Daniel
See if this helps you

SELECT TOP 25
obj.[name],
i.[name],
i.[type_desc],
count(*)AS Buffered_Page_Count ,
count(*) * 8192 / (1024 * 1024) as Buffer_MB
   -- ,obj.name ,obj.index_id, i.[name]
FROM sys.dm_os_buffer_descriptors AS bd
   INNER JOIN
   (
       SELECT object_name(object_id) AS name
           ,index_id ,allocation_unit_id, object_id
       FROM sys.allocation_units AS au
           INNER JOIN sys.partitions AS p
               ON au.container_id = p.hobt_id
                   AND (au.type = 1 OR au.type = 3)
       UNION ALL
       SELECT object_name(object_id) AS name
           ,index_id, allocation_unit_id, object_id
       FROM sys.allocation_units AS au
           INNER JOIN sys.partitions AS p
               ON au.container_id = p.hobt_id
                   AND au.type = 2
   ) AS obj
       ON bd.allocation_unit_id = obj.allocation_unit_id
LEFT JOIN sys.indexes i on i.object_id = obj.object_id AND i.index_id =
obj.index_id
WHERE database_id = db_id()
GROUP BY obj.name, obj.index_id , i.[name],i.[type_desc]
ORDER BY Buffered_Page_Count DESC