In a dental clinic in the port city of Guayaquil, Ecuador, a boy named Javier lowered himself into a chair with a wide grin on his face. Inside his mouth, in contrast, was a grim picture, recalled Dr. Robert Hacker of Branford Dental Care. There were pockets of decay. His gums raged with infection. Overall, it was a portrait of neglect.

Not that Javier was to blame: the 8-year-old lived in Guasmo Sur, an impoverished barrio of Guayaquil with open sewage canals and unpaved roads. He’d never been to a dentist, much less owned a toothbrush. Dr. Hacker pulled out the teeth that were unsalvageable and restored the others.

That was last summer. A year later, Dr. Hacker, along with a local team that included an oral surgeon, two dentists, and three hygienists, flew back to Guiyaquil with some degree of trepidation. “My greatest fear was seeing that nothing we did worked or lasted,” he said. There was no way to predict if any of the toothbrushes they’d given to Javier and the roughly 100 other children had been viewed as mere souvenirs and never used. Or whether the brushing techniques that his daughter Maria and other Branford High School students had painstakingly taught them had gone unheeded. Perhaps the extractions had become infected or the restorations hadn’t held.

Not that the 2009 mission hadn’t already inspired Dr. Hacker to action. A few months after his return from Ecuador, a banner appeared in front of Branford Dental Care’s Montowese Avenue building, announcing the practice had taken on a pediatric dentist and was accepting children whose parents were members of the Husky Plan, a subsidized program that helps Connecticut families afford dental care, among other services. That Branford Dental Care is one of the few Husky providers in the area is of no matter. Nor, it seems, are the attendant costs that might result. “I have no concern that we get too many kids,” said Dr. Hacker. “We can handle it.”

That sense of assurance derives from the realization that the protocol he and the rest of the team developed for treating children in the less-than-ideal conditions of an inner-city clinic could be replicated here, said Dr. Hacker. Parents in Guasmo Sur, like those who are facing economic hardship in Connecticut, are less able to afford nutritious food, explained Kathy Moran, a dental hygienist on the mission. “With cheaper, more sugar-laden processed food, comes more decay. The sooner you can arrest the decay, the greater chance you can save the tooth and structure for the rest of a person’s life.”

Dr. Joseph Gargano, a Branford resident with a dental practice in North Haven who joined the mission to Ecuador for the second year, agreed. “The more kids we can reach, the better,” he said. Still, given the sheer volume of patients they treated there, the procedures they performed couldn’t be as extensive as what they might ordinarily be able to do. “It forced us to be a little creative, to figure out how to provide good quality dentistry with fewer resources.”

Oral surgeon Roger Lowlicht, who has a practice in Branford, went a step further. The first year, the patient population was confined to kids, said Lowlicht, also a Yale professor of oral and maxillofacial surgery. While there was no understating the importance of stopping decay and starting good habits early on, that might no longer be achievable for adults. Why not bring his own equipment and expand their services to anyone who walked in, adult or child? There might be glitches, but it was worth a try.

The risk paid off. Even with twice the number of people coming through the clinic, Dr. Lowlicht extracted 210 teeth during the 8-hour-a-day week the team worked there, 10 times the amount he pulled out the year before. The reason: everything was less of an unknown and, as a result, far more streamlined. And everyone knew their role: doctors, hygienists and, not least, the patients. Not only were they less fearful, said dental assistant Sarah Wolfley. They were, if possible, more appreciative.

A prime example of which, Dr. Lowlicht recalled, was a woman who appeared in obvious discomfort, a woman who would not have been seen the year before. It turned out she had an impacted tooth on the inside of her palate. He cut it up. He picked at it. The root would not budge. All throughout, the woman showed a saintly patience. The tooth, which he finally got out, resembled the head of a hammerhead shark. The next day, the woman came back with gifts of food and cakes. “It was probably a month’s worth of pay for her,” said Dr. Lowlicht, noting that the average annual income in Guasmo Sur is $300 a year.

Dr. Gargano had a similar experience. A young father of two children came in with four of his front teeth partially sheared off in an accident. When it had happened was unclear. After he restored the teeth, the young man, visibly moved, could not thank him enough. “It would have taken him three, three-and-a-half months’ salary to pay for that work,” Dr. Gargano said. For the first time in who knew how long, he could smile without feeling shame about his mouth.

“Considering the conditions they live in, they’re such a warm and giving people,” said Dr. Gargano, whose experience in Ecuador has strengthened his commitment to the Connecticut Mission of Mercy dental clinic, which once a year provides free cleanings, fillings, extractions and root canals to thousands of Connecticut residents in need. “And this year, because we were so much more organized, we all had the time to sense their gratitude for what we’ve been able to accomplish.”

Which was perhaps no more evident than when young Javier opened his mouth one year later. His heart hammering in his rib cage, Dr. Hacker looked in. There was no infection. His teeth looked pristine. His gums were a healthy pink. “It was so nice to see he’d actually brushed his teeth,” said Dr. Hacker. “It was like, wow, this is working.”

The success story was not limited to Javier. Recalled dental assistant Sarah Wolfley: “We’d be walking through the neighborhood and some of the kids we treated last summer would come out and open their mouths. They were so happy to see us and so proud to show us they’d been taking care of their teeth. It was almost as if they’d been waiting for that one moment.”

It may seem perverse that a visit to the dentist would represent a highlight of anyone’s year. But that was one of the takeaways from this summer’s mission, everyone agreed. What it means, said Dr. Hacker, is there’s really no way they can’t go back.