(Reuters Health) - Divers should talk to their dentists about the effects of underwater pressure and whether dental restorations could become painful, say French researchers.
In a laboratory experiment, the study team showed that under high pressure, some dental restorations are more prone to leak than at sea level. That could cause pain during or after a dive, as well as other consequences like making the restored tooth vulnerable to infection, the researchers write in the British Dental Journal.
“Sinus or ear barotrauma are more well known, but dentists are increasingly seeing patients with dental pain after an underwater dive,” said lead author Dr. Caroline Mocquot of Paris University Diderot in France.
“All patients must know about this phenomenon and notify their dentist if they are divers,” she told Reuters Health by email.
Mocquot and colleagues created simulated teeth made from real third molars bonded to composite material and shaped into uniform discs. Ten of the discs incorporated polyester to simulate porosity and 10 did not. These samples were then exposed to a special dye inside bariatric chambers to see how much microscopic leakage occurred between the composite and tooth material.
The discs were submerged six times for 30 minutes each to a pressure of six bars, or the equivalent of about 150 feet underwater.
Researchers found that the porous samples showed 45 percent dye penetration under pressure while the non-porous discs showed 38 percent. That compares to about 30 percent dye penetration, with or without porosity, when samples are exposed in everyday settings without added pressure.
“The next steps would be to test different composite resins and bonding agents in simulated hyperbaric environments,” said Dr. Sangeeta Gajendra of the University of Rochester Medical Center in New York, who wasn’t involved in the study.
In her own recent study of recreational divers, Gajendra found that 41 percent experience dental pain during a dive. “More than half of the teeth affected were molars and had damaged restorations,” she told Reuters Health by email. “Ultimately, we need to have techniques that prevent microleakage and reduce porosities.”
A limitation of the French study is that it uses only 20 samples, and it simulates diving at depths greater than 150 feet, which recreational divers can’t reach, said Vinisha Ranna of the University of Buffalo in New York.
Certified divers, particularly military divers and speleologists, are able to dive at that depth, noted Ranna, who wasn’t involved with the study. “It would be misleading to base clinical recommendations on a study that has been conducted in a simulated environment on a small sample,” she told Reuters Health by email.
Mocquot’s team recommends specific techniques and materials that dentists can use to minimize the likelihood of leakage in restorations - and suggests that divers discuss the options with their dentists when getting work done.
More studies need to be done, however, to understand what’s really happening during a dive and how to prevent the pain, Ranna noted. “There are no established criteria that optimize dental treatment in divers,” she said. “To make recommendations and guidelines, more rigorous studies are needed.”
Dentists and patients should discuss hobbies such as diving when considering procedures with dental extractions, anesthesia and endodontic treatment in particular, the study authors write.
“It is really important for divers to have good oral health, as they will be less likely to have dental pain during a dive,” Gajendra said. “It is imperative for divers to visit their dentists regularly and talk about their diving activities.”
SOURCE: go.nature.com/2yxtsGk British Dental Journal, online September 8, 2017.