TORI SPELLING’s sunken treasure chest becomes booby full bikini bounty.

WHY is Tori so happy NOW to flaunt her bikini body? Because she had her “dented” boobs repaired!

Sources say the former “Beverly Hills, 90210” star decided to treat herself for her birthday and fix her flawed bustline for summer.

“If your car gets a dent, you take it to the body shop and fix it – and that’s what Tori did in a way,” a source close to the mother of four told The ENQUIRER.

“She turned 40 in May and decided to give herself – and her husband – a present that would make them both happy.”

Spelling and her hubby, Canadian actor Dean McDermott,46, are the parents of Liam, 6, Stella, 5, Hattie, 1 1/2, and Finn, 11 months.

She’s wanted to have her breasts redone for a while, the source said, but motherhood kept her too busy.

“Tori finally sat down, did the research and booked an appointment,” revealed the source. “Now she couldn’t be happier, and she’s kicking herself for not doing it earlier.”

As these exclusive photos show, Tori enjoys flaunting her new assets – and a top plastic surgeon says her procedure produced fabulous results.

“Tori looks great!” Dr. Anthony Youn, who hasn’t treated Spelling, told The ENQUIRER.

“It appears that she may have had a pectus excavatum, which is a chest that looks ‘caved in.’ I suspect that she may have had it repaired with fat injections, which work nicely to fill in areas like chest depressions.

“The surgeon did a nice job and may have even upsized her breast implants.”

Tori’s pal added: “She loves her new boobs and so does Dean. He’s actually gone out and bought a bunch of new bikinis for her. Tori liked her body before, but now she LOVES it!”