Free-scoring Hearts maintained their nine-point advantage at the top of the Championship with yet another comprehensive home win.
Goals from Osman Sow, Prince Buaben, substitute Jason Holt, Callum Paterson and Billy King did the damage as the rampant Jambos made it 28 points from a possible 30 this season.
Robbie Neilson’s side have now netted 19 times in their last four games at Tynecastle.
Hearts dominated the opening exchanges but were kept frustrated by a well-organised Dumbarton side.
The breakthrough came in the 26th minute when Sow powered home a header from a superb Paterson delivery from the right.
Dumbarton’s Andy Graham almost levelled when he diverted a Scott Linton delivery towards goal in 31 minutes but Neil Alexander dived to his right to claw the ball out for a corner.
Hearts extended their lead in 38 minutes when Buaben’s tamely-struck penalty kept squirmed beyond Dumbarton goalkeeper Danny Rogers after Billy King was fouled by Linton as he ran on to a Paterson through ball.
The hosts almost scored a third right on half-time but Rogers made a magnificent point-blank save to keep out Soufian El Hassnaoui’s close-range effort from another Paterson delivery.
Hearts winger Sam Nicholson went desperately close in 54 minutes when he received a short corner from King, jinked in from the left and smacked a powerful angled strike off the underside of the bar.
But a minute later, the Jambos stretched their lead when Holt, who had replaced Sow at half-time, drilled home a low angled effort from the edge of the box.
Dumbarton pulled one back in 72 minutes when Garry Fleming volleyed in from 10 yards out after Colin Nish had nodded a Jordan Kirkpatrick corner back into the danger area.
But Paterson made things comfortable again when he rose to head home a King corner in 83 minutes.
And King completed the scoring with two minutes left when burst into the danger area and rifled home a low shot from the edge of the box, ensuring an uncomfortable afternoon for Dumbarton manager and former Hibs captain Ian Murray.
Hearts (4-4-2): Alexander; Paterson, Ozturk, McGhee, Eckersley; King, Gomis, Buaben (Pallardo 68), Nicholson (Walker 75); Sow (Holt 46), El Hassnaoui. Subs: Hamilton, McHattie, McKay, Buchanan.
Dumbarton (4-4-1-1): Rogers; Van Zanten, Graham, Taggart, Linton; Gilhaney, Agnew (MacDonald 64), Kirkpatrick (McDougall 78), Megginson; Fleming; Nish (Campbell 73). Subs: Ewings, Mair, McLaughlin.
Ref: John McKendrick