Root refrained from pointing the finger at Gabriel after stumps but acknowledged the quick may regret his choice of words.
"Sometimes people say things on the field that they might regret, but they should stay on the field," Root said.
"It's Test cricket and he's an emotional guy trying to do everything he can to win a Test match. He's a good guy who plays hard cricket and is proud to be in the position he is.
"The battle was a good contest, he's had a wonderful series and he should be proud.
"I don't want anything said in the middle to ruin what's been a good Test series for him and his team."
According to The Telegraph, umpires Rod Tucker and Kumar Dharmasena warned Gabriel about using abusive language but reports suggest no further action has been taken.
Interim West Indies coach Richard Pybus said: "Nothing has been reported to me. But if a comment was made, we'll review it, and if it was untoward, we'll be addressing it."
English cricket writer Nick Hoult said match referee Jeff Crowe was satisfied with how the on-field officials dealt with the matter.
Daily Mail cricket correspondent Paul Newman said Gabriel needed to be punished if he said something to bring about that sort of response from the visiting captain.
Writing for ESPN Cricinfo, George Dobell suggested if anything inappropriate was said, it may be partly because of the different culture in the Caribbean.
"The incident may speak of a culture clash as much as anything," Dobell wrote. "Radio stations in some parts of the Caribbean regularly play music with lyrics that would be viewed as homophobic and unacceptable in the UK — or many other places — while some homosexual acts remain illegal across much of the region."
England's innings of 4/325 was comfortably its best, and longest, of the tour and although there were more disappointments for openers Rory Burns and Keaton Jennings, 69 from Denly offered cause for cautious optimism.
Root's ton was his 16th in Test cricket — to put him level with Michael Atherton, Graham Thorpe and Herbert Sutcliffe — and his fifth overseas, a reminder that despite his recent wobble he remains the bedrock of England's batting.
The tourists began the day at 0/19 and looking to build on what was already a strong position, 142 ahead.
Things remained that way for just a few seconds, Burns flicking Keemo Paul's first ball of the day to square leg to depart for 10.
Jennings scored 23 from 99 balls before he was bowled in ugly, if unfortunate, fashion after Alzarri Joseph's delivery took a detour off his thigh pad. Denly was dropped on 12 and brought up his fifty in style, lifting a four over mid-on and then crunching Kemar Roach down the ground.
His innings came to an end when he got a thin edge off Gabriel's bowling.
Jos Buttler joined Root at the crease and the pair added 107 before Roach nipped one in at Buttler and took his off stump.
Joseph helped Root to three figures, providing a full toss which the skipper gratefully punched to the ropes, while Ben Stokes was 29 not out at stumps.
Root said he will assess the match situation overnight before making a decision about when he might declare.
"If it (the pitch) starts to misbehave like it did when they took the new ball, more frequently than the old ball, that might give us a little nudge to pull out," he said.
The hosts have already won the three-match series 2-0 after dominant wins in North Sound and Bridgetown.
