Dr. Marc Hendler has a good life in New York. He has a successful dental practice on Manhattan’s East Side, a home in Scarsdale, a wife and four kids. On May 16, he’ll leave it all for Iraq, embarking on his second tour of duty as a colonel in the National Guard.

What kind of person leaves behind his comfortable life to spend four-and-a-half months in a war-torn, brutally hot, extremely inhospitable place? His family and friends don’t get it. “They think I’m a meshuggeneh dentist,” he said.

Hendler, 56, has a healthy sense of humor, his blue eyes sparkling as he tosses out rapid-fire quips. He jokes about sweating bullets in Iraq, about the geckos and scorpions that would attack him when he would go outside to use the bathroom at night. “I was more afraid of them than the Iraqi soldiers,” he said with a smile.

But behind the cheerful demeanor is a man who has experienced some dark days. Until 1998, Hendler was a father of five. His son, Jason, was driving with some other kids on the Bronx River Parkway when he got into a car accident. The others survived, but Jason — who was wearing a seatbelt—suffered a ruptured aorta. He was 16 and a half when he died. “I think about it every day and cry,” Hendler said. “The heart is broken but it still beats.”

Three years later came 9-11.

The National Guard asked Hendler, who joined up in 1970, to help with forensics at the World Trade Center. He came in every Thursday for nine months. “It was very rewarding, fulfilling,” he said. “I felt good about finding closure.”

Two months later, Flight 587 crashed into Belle Harbor, Queens. Again, Hendler assisted with forensics. But while there were no young children in the Twin Towers, there were some very young victims of the plane crash. It was almost too much for Hendler. “I cried during that,” he said. “That, to me, was worse.”

Fast-forward to 2005, when the war in Iraq was entering its third year. They need a dentist in Iraq, Hendler was told. As the most senior of the three dentists in the New York State National Guard, Hendler went first. He was there for three months.

“It was like a brotherhood,” he said. “I got to see soldiers from all over. “There’s no safe zone. They shot at the helicopter once. At nights, they’d lob rockets and mortars but usually missed. And then they blew up a pipeline. I thought it was five feet away, but it was five miles away.”

Already balding, Hendler shaved his remaining hair off to cope with the scorching heat. He worked six days a week, 12 hours a day. He lived for e-mails from loved ones. “That was the best, the e-mail,” he said. “It’s hard to get to the phone.”

Sometimes Hendler would get a care package in the mail. “I would look at it, see how nice it was, and immediately give it away to the soldiers because they had less than me,” he said.

For Rosh HaShanah, Hendler’s synagogue, Temple Israel Center in White Plains, sent him nuts and honey. He brought it to services at the base. “The rabbi was always hoping we’d have nine soldiers at his service,” he said. “He was going to count the Torah as the tenth.

He never had more than five or six, except on Rosh HaShanah, there were 15 men and women. He was so happy. “It was very nice to be together in this mess.”

Now, Hendler’s going back to Iraq. He’ll have to say goodbye all over again to his wife, his children and his 80-year-old mother. He’ll take a break from the dental office — the hiatus is “a financial disaster,” he said — and from his volunteer work as a firefighter in Scarsdale. Fortunately, Hendler was able to schedule this four-and-ahalf month stint after his son Jonathan’s bar mitzvah.

By working with the troops, Hendler continues a family tradition: his grandfather served in World War I and his father was stationed in the South during World War II. “The first time I went to Iraq, I was 50 percent against the war,” Hendler said. “Now I’m 100 percent against the war. Democracy’s a good thing, it may not be for everyone. I don’t have an answer to any of this.”

But he doesn’t let that affect his mission. “I’m proud and privileged to be able to offer services to the brave men and women,” he said. “I feel very good about myself for doing it.”

Hendler couldn’t disclose exactly where he’s going, but said he’ll be near Ur, “where the Jews are from, the beginning of Jewish civilization,” he noted proudly. His spiritual beliefs, he said, have helped him stay strong.

“My greatest wish is that Jason didn’t die,” he said. “My second wish is that I would replace him, but that’s not gonna happen. My third wish is that maybe our souls can be together sometime.” WJC