The fissure system in the first molar was sufficiently complex to require attention. Following the original opening there proved to be an extensive lesion under the lingual fissure so the cavity outline was modified and extended in the region of the lesion only. The remaining fissures were explored conservatively to make sure there was no other large extension. The fissures on the second molar were similarly explored but that proved to be a #1.1 lesion only.