Hi,
This is not recommended, as BY default material number is set to length 18 as suggested By SAP in ECC & BI .
Material number will be set in OSML tcode.
if you are sure about first 10 chars are zero & need to be remove can be done by
1. using routine code in BI
2.check once by Removing alpha conversion property for that iobj in sap BI with maintaining length as 8 .
Regards,
Seshu.P