Under US regulations, medical device manufacturers are required to report malfunctions and adverse events to the FDA within 30 days. These reports feed into the MAUDE database, which regulators, clinicians, researchers, and the public rely on to identify potential safety signals that may warrant product recalls, label changes, or other corrective actions. For the system to function as intended, the reports must be complete and accurate. Yet earlier programs, most notably the Alternative Summary Reporting program, allowed manufacturers to submit millions of adverse events as bulk summaries rather than as individual case reports, a policy framed as a way to reduce the burden on industry. The FDA ended that program in 2019 amid concerns that it was masking safety signals, but similar summary reporting exemptions remain in use today, and until now their accuracy, completeness, and compliance with FDA rules were largely unknown.

To close that gap, researchers analyzed all adverse event summary reports submitted to MAUDE between July 2019 and June 2025. They looked for four specific types of failure: incomplete identification of the device or use problem involved, undercounting of the number of adverse events, failure to correctly identify the submission as a summary report, and delays in reporting serious adverse events beyond the regulatory deadline. The dataset they examined was substantial. During the six-year study period, 6,308 summary reports were submitted to the FDA, containing a total of 159,503 adverse events. The majority of these events involved high-risk devices, the very category of products where timely safety intelligence matters most.

The results paint a troubling picture of a reporting pipeline riddled with defects. Fifty-seven percent of the summary reports identified no device or use problem at all, leaving regulators without a clear indication of what went wrong. Thirty-eight percent contained insufficient information to evaluate the events described. Eleven percent were incorrectly identified as non-summary reports, meaning they would not be flagged or processed as aggregated submissions. Seven percent incorrectly listed only one event in the number of events field, even when multiple adverse events were involved. Perhaps most alarmingly, 55 percent of the reports exceeded the FDA’s 30-day reporting deadline, meaning that more than half of the aggregated safety information arrived late, in some cases long after the window in which it could have contributed to a rapid regulatory response.

The scale of the problem is growing rather than shrinking. The researchers note that the number of summary reports submitted to the FDA, and the number of adverse events contained within them, more than doubled between 2020 and 2024. That trajectory suggests manufacturers are increasingly relying on bulk summary mechanisms to discharge their reporting obligations, even as the quality of those submissions falls short of the standards the agency itself has set. In a passive reporting system that depends entirely on the diligence of the regulated industry, systematic gaps in data quality translate directly into blind spots in national device surveillance, potentially delaying the recognition of hazards affecting widely implanted or widely used products.

The authors of the study are candid about the limitations inherent in their analysis. Passive adverse event reporting has well-known weaknesses, including incomplete ascertainment of events in the real world and the absence of a denominator of device use against which event rates can be calculated. The researchers also lacked access to publicly available information on the specific requirements governing the summary reporting exemptions, which constrained their ability to assess compliance against detailed regulatory criteria. Even so, they argue that identifying and correcting the flaws documented in the study is vital, particularly given the accelerating volume of summary reporting. Immediate improvements, they write, are needed to better protect patient safety and adhere to the transparency principles outlined by the FDA, adding that making serious adverse event reports fully visible and accessible is critical to patient safety.

The study’s publication was accompanied by a linked editorial from Koji Todaka of Kyushu University Hospital in Japan, who frames the findings as a challenge to the fundamental purpose of the reporting system. The MAUDE database exists to support public scrutiny of medical device safety, and reports that are incomplete, mislabeled, or late undermine that mission, he argues. When the public cannot see an accurate and timely account of adverse events associated with the devices used in their care, trust in postmarket surveillance erodes, and the evidence base for clinical decision-making weakens accordingly.

Todaka proposes a set of reforms aimed at restoring confidence in the system. Regulators, he suggests, should require accurate and timely summary reporting, standardized device identification, and clear links between adverse event reports and device registries. Standardized identification is particularly consequential, because ambiguous device problem descriptions and inconsistent device identifiers make it difficult to aggregate reports across manufacturers and time periods, which is precisely the kind of aggregation needed to detect a safety signal. He also recommends that researchers integrate spontaneous reports, registry data, and linked healthcare records rather than treating any single data source as definitive, reflecting a broader consensus that passive reporting alone cannot carry the full weight of postmarket safety surveillance.

Change may be on the horizon within the FDA itself. The agency is currently transitioning to a new Adverse Event Monitoring System, or AEMS, designed to consolidate existing reporting systems and publish adverse event reports in real time. If the new platform enforces structured data entry, validates event counts, timestamps submissions against the 30-day requirement, and makes serious adverse event reports immediately visible to the public, it could address many of the deficiencies documented in the BMJ analysis. The transition also presents an opportunity to revisit the summary reporting exemptions themselves, tightening the conditions under which bulk submissions are permitted and requiring manufacturers to supply the device and problem information that more than half of current reports omit.

The stakes of this administrative infrastructure are far from abstract. High-risk devices, including implants, cardiac devices, and surgical equipment, are used in millions of patients, and a delayed or obscured safety signal can mean continued exposure to a malfunctioning product for months or years. The BMJ study demonstrates that the mechanisms meant to catch those signals are, in their current form, leaking information at every stage: at submission, in classification, in event counts, and in timing. As the researchers and the accompanying editorial both emphasize, transparency builds trust and evidence improves safety, and both are essential to effective postmarket surveillance and safer medical devices. Whether the FDA’s new monitoring system, combined with stricter oversight of summary reporting, can close the gaps identified in this study will be a defining test of the next chapter of medical device regulation in the United States.

Subject of Research: Accuracy, completeness, and timeliness of summary adverse event reporting to the FDA MAUDE medical device safety database

Article Title: Medical device adverse event reports are often incomplete, inaccurate, and delayed

Article References: Medical device adverse event reports are often incomplete, inaccurate, and delayed. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: medical devices, FDA, MAUDE database, adverse event reporting, postmarket surveillance, patient safety, summary reporting exemptions, BMJ, device regulation, safety signals, transparency, regulatory compliance

The MAUDE database is the FDA’s primary passive surveillance system for medical device problems. Manufacturers, importers, and user facilities are required to submit reports of device-related deaths, serious injuries, and malfunctions, while the public and health professionals may file voluntary reports. Because it aggregates real-world experience across thousands of dental sleep medicine practices, it offers a view of device safety that clinical trials, which typically follow small cohorts for limited periods, cannot match. Glick and Richardson analyzed this publicly available database to identify adverse event reports associated with oral appliances used for sleep-disordered breathing, and to examine how the categories of reported harm have trended across the reporting period.

Oral appliance therapy, in its most common form, uses a mandibular advancement device: a two-arch dental appliance that holds the lower jaw forward during sleep, tightening the upper airway and reducing collapse that drives apneic events. The approach is endorsed in clinical practice guidelines from the American Academy of Sleep Medicine and the American Academy of Dental Sleep Medicine as a legitimate therapy for patients with obstructive sleep apnea, particularly those who are intolerant of CPAP or prefer an alternative. Recent studies cited in the letter underscore why the therapy has gained ground. One 2025 analysis found that oral appliance therapy is highly efficacious at reducing sleep apnea-specific hypoxic burden, a metric predictive of cardiovascular morbidity and mortality. Another 2026 study comparing long-term outcomes of mandibular advancement devices with CPAP found meaningful therapeutic efficacy in patients with obstructive sleep apnea, reinforcing the devices’ clinical standing.

Yet the same mechanism that makes these appliances effective, mechanically protruding the mandible night after night for years, is also the source of their characteristic side effects. The dental sleep medicine literature has long catalogued a spectrum of harms: temporomandibular joint discomfort, myofascial pain, dental pain, occlusal changes in which the bite shifts as teeth move under sustained force, dry mouth, hypersalivation, and gum irritation. A 2025 systematic review and meta-analysis comparing side effects across different mandibular advancement devices found that these effects are common and vary by device design, a point that matters because the market now includes a wide range of custom, semi-custom, and over-the-counter products. The American Academy of Dental Sleep Medicine has published recommendations for managing these side effects, emphasizing monitoring and follow-up as integral parts of therapy rather than optional extras.

Against that backdrop, the rising volume of adverse event reports in MAUDE is a signal that cannot be dismissed as statistical noise, even though passive reporting systems carry well-known caveats. Report counts in such databases are influenced by many factors beyond true incidence: the size of the exposed population, growing awareness among clinicians and patients that reporting is possible, expanded marketing of oral appliances, and the rise of teledentistry pathways that deliver dental sleep medicine with fewer in-person touchpoints. The letter’s authors note the growth of teledentistry in dental sleep medicine as an innovation that requires safeguards, a nod to the possibility that remote care models, while expanding access, may change how side effects are detected, managed, and reported.

The second half of the finding, the shifting categorical trends, is arguably the more consequential one. When the composition of adverse event reports changes over time, it can indicate that the nature of device use is changing, that new device designs are introducing new failure modes, or that the patient population receiving appliances is evolving. Prior work on the MAUDE database has already explored this terrain: a 2025 analysis in Respiratory Medicine examined adverse events associated with mandibular repositioning appliances specifically, establishing that the database contains enough signal to support categorical analysis. By updating and extending that picture, Glick and Richardson provide dental sleep medicine clinicians with a current map of where reported harms are concentrating, information that can guide the follow-up questions dentists ask and the monitoring protocols they adopt.

For patients, the practical message is that oral appliance therapy is not a set-and-forget intervention. Dental sleep medicine standards published in 2025 for screening, treatment, and management of sleep-related breathing disorders in adults using oral appliance therapy stress that therapy begins with proper screening and diagnosis, continues with device fitting and titration, and depends on ongoing surveillance of both efficacy and side effects. The side effects documented in the literature, particularly the dental and skeletal changes that can accrue silently over years of use, are precisely the kind of harm that a patient sleeping alone with a remote provider may not notice until the bite has shifted. Regular in-person evaluation of the bite, the temporomandibular joints, and the airway response remains a cornerstone of safe therapy.

The study also arrives at a moment when the dental sleep medicine field is professionalizing rapidly. More dentists are seeking certification, more primary care physicians are referring patients who cannot tolerate CPAP, and more consumers are encountering oral appliances through advertising and direct-to-consumer channels. Each of these trends enlarges the population of device users, and each carries implications for the adverse event reporting stream. A database like MAUDE cannot by itself separate increased use from increased risk, which is why the authors’ framing of increasing reports alongside shifting categorical trends is careful: it documents what is being reported and how the pattern changes, rather than claiming a precise incidence rate that passive surveillance cannot deliver.

That limitation is worth stating plainly, because it defines what the study can and cannot tell the public. MAUDE reports are voluntary in part, unverified in most cases, and subject to duplicate, incomplete, and delayed submissions. The FDA itself cautions that the database cannot be used to calculate incidence. What it can do, and what this research letter does, is reveal the shape of the harm landscape: which categories of adverse events are appearing, whether reports of temporomandibular disorders, dental changes, or other complications are growing relative to one another, and whether the overall reporting trajectory is climbing. For a therapy whose user base is expanding and whose delivery models are changing, that shape is exactly the information clinicians, device designers, and regulators need to prioritize.

The authors, who analyzed the data jointly and drafted the manuscript together, report no funding for the work; Richardson discloses no conflicts of interest, while Glick discloses an ownership stake in Ember Sleep and consultancy work for the American Academy of Dental Sleep Medicine, disclosures that are relevant context for readers weighing the letter’s conclusions. The study was received in April 2026, revised in June, accepted on 1 July, and published on 22 July 2026 in the journal’s volume 22 as article number 121. Its brevity, a research letter rather than a full study, reflects the nature of the evidence base: a public database, a categorical analysis, and a clear signal that warrants prospective research. For the millions of patients who wear a mandibular advancement device every night, and for the dentists who fit them, the takeaway is not alarm but vigilance. Oral appliance therapy remains a guideline-endorsed, increasingly evidence-supported treatment for obstructive sleep apnea. The rising and shifting adverse event reports in the FDA’s own surveillance data are a reminder that its safety depends on the follow-up that happens after the appliance leaves the dental chair.

Subject of Research: Adverse event reporting trends for oral appliances used in obstructive sleep apnea therapy

Article Title: Increasing reports and shifting categorical trends in adverse events for oral appliances

Article References: Glick, A., & Richardson, S. E. (2026). Increasing reports and shifting categorical trends in adverse events for oral appliances. Journal of Clinical Sleep Medicine, 22(1), Article 121. https://doi.org/10.1007/s44470-026-00139-y

Image Credits: AI Generated

DOI: 10.1007/s44470-026-00139-y

Keywords: oral appliance therapy, obstructive sleep apnea, MAUDE database, adverse events, mandibular advancement devices, dental sleep medicine, temporomandibular disorders, FDA surveillance, teledentistry, CPAP alternatives, side effects, sleep disorders