An electrical malfunction is suspected as the cause of a fire in a dental laboratory in the Pan Am building on Kapiolani Boulevard overnight.

Four floors of the 17-story office building suffered extensive water damage from the sprinkler system as a result of the blaze, a fire department spokesman said today.

Firefighters responded to an alarm at the building at 11:27 p.m., said Capt. Terry Seelig.

The alarm was activated on the 11th floor, however the fire actually started on the 13th floor in the offices of DenTek International Inc. dental laboratory and was extinguished by building’s sprinkler system, Seelig said.

Water from the sprinkler system flooded offices in the 13th to the l0th floors.

No one was injured and there was no immediate estimate of damage.

Firefighters worked until 3 a.m. helping to clear the building of water, Seelig said.