Zachary Kouri considers himself lucky.

Unlike some dentists, he could reopen his practice in Des Moines after the novel coronavirus forced him to limit his work to emergency cases for two months. But reopening meant a week or so of 15-hour days, unplanned construction on his office, time spent hunting for affordable personal protective equipment and the painstaking work of rewriting office safety protocols.

As states begin allowing dentists to resume treating patients, they navigate a complicated logistical reality: In conducting their duties in and around patients’ mouths, they land especially close to the respiratory system.

But unlike doctors treating covid-19 patients, dentists were not considered front-line workers and had largely been left out of the nationwide triaging of PPE until late May, according to interviews with leaders of several state dental associations.

They are retooling their offices to meet new and stricter health and safety guidelines. And because many of their tools can cause wide sprays of respiratory particles, many dentists are trying to determine the services they will be able to provide when patients return for more routine care.

Kouri, president-elect of the Iowa Dental Association, was able to shoulder the cost of retrofitting his office. The building that houses his practice is paid off. He doesn’t have fresh student loans to worry about. So far, he has been able to afford the investment required to outfit his practice with the extensive PPE he never needed before the arrival of covid-19, the disease caused by the novel coronavirus. He knows other dentists, particularly younger dentists still paying off loans or renting out space, are facing far steeper climbs to recovery.

“I’m really worried for some of the really small practices, practices in rural Iowa and younger dentists’ practices everywhere,” Kouri said.

Kouri had to add a locker room and changing room to ensure his staff can remain safely clothed. He also added a laundry room and bought reusable fabric gowns after he found that building the infrastructure to wash gowns would prove cheaper than buying paper gowns that were no longer safe to recycle, especially as competition to buy PPE heats up.

He purchased air purifiers to help remove contaminants from the air so they don’t linger or recirculate through the heating and air-conditioning system. Like many dentists, Kouri is going to start spacing out appointments to give his staff time to decontaminate themselves and their facilities.

The Centers for Disease Control and Prevention and World Health Organization suggest respiratory droplets expelled when an infected person coughs, sneezes, talks or breathes are the primary way the virus spreads.

Many tools involved in teeth cleaning — the spinning polishing brush, for example — create that kind of spray. Key tools in other routine procedures — such as the drill used to fix a cavity — also rotate and create spray.

In a webinar conducted for American Dental Association members in May, Donald Milton of the University of Maryland School of Public Health and Purnima Kumar of Ohio State University School of Dentistry warned colleagues that current research suggests the coronavirus might also linger as aerosols, smaller respiratory droplets not heavy enough to fall from the air. If it does, spray from one procedure could mean leaving infected particles in the air for the next, threatening the safety of multiple patients.

Recommended protective measures vary widely in cost. Air purifiers, ultraviolet lamps and well-directed heating and cooling systems are among the measures that can help ensure clean air from client to client. The CDC, American Dental Association and most state dental associations are strongly suggesting that all dentists wear N95 masks and that head-to-toe coverings be replaced after each patient.

Multiple dentists who were interviewed said that while they regularly wore more basic surgical masks when treating patients, they did not normally rely on the more protective N95 masks. Most dentists, many almost entirely out of work for the last two months, did not budget for those upgrades, fueling fears some dentists will lose their practices.

“We’re not going to be seeing patients like we used to in terms of quantity, which is another issue for a dental office,” said Richard Nagy, president of the California Dental Association. “So we’re going to have to increase PPE costs and decrease patient volume, which affects how businesses can run for sure.”

Nagy and other leaders of the confederation of dentists were relieved when California health authorities told them a million N95 masks could be theirs if they would pick them up in Fresno. Early in the pandemic, dentists emptied their stockpiles of masks, heeding an urgent call for PPE. They had been waiting to restock their supplies. A trip to Fresno was a small price to pay.

So the dental association dispatched four trucks to Fresno, then made the five-hour-plus trip to a dental supply company in Reno, Nev., from which they distribute goods. The dental group planned to distribute the masks to California dentists. A few days later, leaders of the group received a call telling them they had to return the masks, with little explanation.

Those million masks wouldn’t have solved the widespread problems California dentists — like those around the country — are having getting the equipment they need. Even health-care workers treating covid-19 patients directly have found themselves facing a profound, and sometimes deadly, shortage.

But for dentists, the trouble is compounded by the fact that most jurisdictions did not consider them front-line personnel. Not until May 21 did the Federal Emergency Management Agency elevate dentists to fourth on their PPE priority list, according to a statement released by the American Dental Association.

To reopen safely in accordance with CDC or American Dental Association guidelines, dentists are supposed to use “the highest level of PPE available.” But dentists have been confronting skyrocketing prices for equipment.

A survey of dentists conducted by the Massachusetts Dental Association found dentists there estimated it would cost $150,000 to $300,000 to restart their practices after being closed or open to only emergency patients for so long.

“It’s hard on a lot of dentists,” said Douglas Robertson, president-elect of the West Virginia Dental Association. “They’ve been able to see emergency patients, but it doesn’t really even cover the cost of keeping your staff and other office overhead expenses.”

Dental associations across the country have begun lobbying insurers for assistance, with varying success. Nagy said a few California insurance companies have added a new code to their list of reimbursements — D1999, which signals a small reimbursement for PPE used in treating a patient.

In Massachusetts, Delta Dental, a major provider of dental insurance, recently began offering dentists an advance on a percentage of future claims.

“That’s short-term relief to a long-term problem,” said Janis Moriarty, president of the Massachusetts Dental Society. “But it just kicks the can down the road because they’ll help you up front, but later in the game it’s coming off the reimbursements we would expect. It’s not ideal by any means.”

The American Dental Association’s Health Policy Department recently studied the potential impact of the coronavirus crisis on dentists and found that if the situation doesn’t change dramatically soon, the results could be catastrophic: Association projections suggest nearly 25 percent of dentists could go out of business.

“Then, you’re going to have an access-to-care issue. Who’s going to see all these patients?” Nagy said. “It’s going to affect the Medicaid and low-income patient. It’s going to be a domino effect, which is why we’re working to try to prevent these offices from closing.”

In some parts of the industry, the dominoes have already started falling. Many dental hygienists have been furloughed or gone on partial unemployment for weeks now, and unlike the dentists who normally employ them, they might not be returning to work any time soon.

On June 3, the CDC released guidance for dental offices that included more detailed recommendations and offered suggestions of ways dental offices could provide routine care safely.

“Dental settings should balance the need to provide necessary services while minimizing risk to patients and dental healthcare personnel,” the guidance said.

Many dental practices say they are not going to conduct routine teeth cleanings handled by hygienists, with the exception of some offices in states that have allowed the full-fledged reopening of practices.

Teeth cleanings rely on tools that can create spray, and spinning brush-heads and polishers are among the tools most dentists are trying to avoid.

“Think of if you are an asymptomatic covid-positive patient that doesn’t know you have it and you sit down and I provide care to you and generate all these aerosols. In most dental offices, prior to covid, there might be a five-minute gap between the time you leave and the time another patient sits down,” said Matt Crespin, president of the American Dental Hygienists’ Association. “So those aerosols are then hanging in the air and potentially infected the next person who sits in my chair.”

As states weighed reopening, Crespin argued for dentists to postpone opening their offices until it was safe for hygienists to conduct their normal duties.

In mid-March, the hygienists association created an email inbox for members who might have concerns about their work. He said that email box is still being flooded with “hundreds of emails.” Some of those stories are from hygienists concerned about going back to work because they were not sure their office would be properly outfitted by the time they did so.

Some dentists have resisted the pressure to reopen, including the office where Crespin says he goes for dental care. In the meantime, he and others are trying to brainstorm ways to make going to the dentist under newly required conditions more tolerable for those who already find it traumatic.

One crucial step, he believes, will be to let patients get to know the people taking care of them — even if they might be dressed head-to-toe in protective gear that he says “makes us look like aliens.” He wonders if patients should be shown a picture of their hygienists at the start of each visit, just to remind them that the people taking care of them are human, too.