The west Wales outfit have been successful in all three seasonal derbies after victories over Ospreys and Cardiff Blues, keeping them at the top of Conference B.

Scarlets' tries came from James Davies, Tom Prydie, Dylan Jones, Aled Davies, Aaron Shingler, Will Boyde and Rhys Jones, with Dylan Jones and Rhys Patchell supplying a total of 12 points with the boot.

Dragons' points came from a Sarel Pretorius try late in the second half, converted by Angus O'Brien, and two first-half penalties from Arwel Robson and Carl Meyer.

Tighthead prop Samson Lee returned to action having been out since the European Rugby Champions Cup clash against Bath in October. Lee was one of 11 personnel changes from the side that secured victory over Cardiff Blues and was part of an all-international front row that also included Rob Evans and Ken Owens.

It was one-way traffic in the opening 40 minutes as Scarlets moved into a 19-6 lead.

Dragons took the lead after 14 minutes with Robson's penalty but after that Scarlets were dominant in the scrum and line-out and scored the first of their tries when James Davies crashed over from a driving maul.

Dragons were not helped that Robson limped off and then they were so under pressure in the front row that coach Bernard Jackman changed both his props Luke Garrett and Nicky Thomas.

That did not make much difference as Scarlets scored two tries in the space of three minutes. The first one came from Prydie, who latched on to Steffan Hughes' kick over the line.

The second came when Dan Jones went over under the posts after good link-up work from Owens and James Davies.

There was some respite for Dragons, with Meyer putting over a penalty two minutes before the break.

At the start of the second half Meyer was short with a long-range penalty before Scarlets went over for four tries in the space of 14 minutes.

Aled Davies started the spree after 52 minutes and confirmed the bonus point after good work by Patchell and Steve Cummins.

That gave Scarlets the confidence to run the ball and there were further tries from Shingler, Boyd and replacement Rhys Jones.

There was a late consolation for Dragons when Pretorius went over and O'Brien converted.