Can Childhood Stress Make Molars Come In Earlier?
Research shows that children from lower-income backgrounds and those who go through greater adverse childhood experiences get their first permanent molars sooner. The findings align with a broader pattern of accelerated development often seen under conditions of early-life stress.
A 2021 study suggests it may be linked. Researchers at the University of Pennsylvania found that children from lower-income families and children who had more adverse childhood experiences tended to get their first permanent molars earlier. It's an association, not proof of cause, and the researchers stress that the timing of a child's molars says nothing useful about that individual child. For parents, nothing about routine dental care changes.
What did the study look at?
The researchers wanted an inexpensive, early sign of whether stress speeds up a child's development. Earlier puberty is a known marker, but it comes too late to be much help. In other primates, the timing of molar eruption tracks the length of childhood, so the team looked at teeth.
They started with 117 children aged 4 to 7 who were already in brain-imaging studies at Penn. The MRI scans happened to show the developing molars clearly. Working with Penn Dental Medicine, the team rated how far each first permanent molar had come in, then compared those ratings with family income and the number of adverse childhood experiences each child had, after accounting for age and sex.
To check the result, they repeated the income analysis with 1,973 children in the National Health and Nutrition Examination Survey, a national U.S. dataset.
What did they find?
In the Penn group, both lower family income and more adverse childhood experiences were linked with earlier eruption of the first permanent molars.
In the national dataset, the link between lower income and earlier molars held up.
The team also saw differences by race, which they said need further study.
What are the study's limits?
The first group was small and came from one city. The national dataset measured teeth differently and could only test income. Most importantly, the study shows that two things tend to occur together across groups of children. It doesn't show that stress causes earlier molars, and it can't predict anything for a single child. The researchers were clear that parents shouldn't worry, or feel reassured, based on when their child's molars arrived.
What does this mean for your child's teeth?
First permanent molars usually come in around age six, behind the last baby teeth, and children often don't notice them. Whenever they arrive, they need the same care:
Brush them twice a day with fluoride toothpaste. They sit far back and are easy to miss.
Ask your child's dentist whether sealants make sense once the molars are in. The deep grooves on these teeth are where many childhood cavities start.
Keep up regular dental visits.
If you'd like more on what teeth can record about early life, read about growth marks in baby teeth. For young children's care in general, see our parent's guide to early childhood dental problems.
Sources
McDermott CL, Hilton K, Park AT, et al. Early life stress is associated with earlier emergence of permanent molars. Proc Natl Acad Sci U S A. 2021;118(24):e2105304118. doi:10.1073/pnas.2105304118. Retrieved via PubMed (PMID 34103399).
Penn Today. A link between childhood stress and early molars. June 7, 2021. Retrieved 2026-10-06.
About the author. CJ Henley, DMD, is a general dentist in Jacksonville whose practice focuses on cosmetic and restorative dentistry, dental implants and dental care around head and neck cancer. Meet Dr. Henley.
CJ Henley, DMD, PA · 3675 Hendricks Avenue, Jacksonville, FL 32207 · 904-398-1549
Updated October 2026.
Did Dental Aerosols Spread COVID-19? What a 2021 Study Found
A new study's findings dispel the misconception that patients and providers are at high risk of catching COVID-19 at the dentist's office.
During the COVID-19 pandemic, one worry was that the fine spray from dental drills and cleaning instruments would carry the virus from a patient's saliva across the room. A study published in May 2021 by researchers at Ohio State University found that most of the microbes in that spray came from the water used during treatment, not from saliva, and the virus was not detected in any of the spray samples. The study was small and done with infection-control measures in place, so it supports those measures rather than showing that dental care carries no risk.
What question did the study ask?
Dental instruments such as high-speed drills and ultrasonic scalers produce a fine mist. Earlier studies had shown that bacteria land on clinicians' faces, the patient's chest and surfaces several feet away. Those studies mostly grew bacteria on plates. They could not say where the microbes came from, and saliva was assumed to be the source. At the start of the pandemic, that assumption led to wide closures of dental offices.
The Ohio State team asked a narrower question: when aerosols land around the dental chair, how much of what they carry actually comes from the patient's saliva?
How was it done?
Patients: 28 adults treated at Ohio State's College of Dentistry between May and July 2020, during ultrasonic cleaning, implant surgery or fillings with a high-speed drill.
Samples: saliva and the irrigation water were collected before each procedure. Afterward, droplets that had condensed on the clinician's face shield, the patient's bib and a spot about six feet away were collected.
Testing: genetic sequencing identified the bacteria in each sample and traced them to their likely source. A separate test looked for the COVID-19 virus.
Precautions in place: patients used a mouth rinse before treatment, and high-volume suction was used in the mouth.
What did it find?
About 78 percent of the microbes in the aerosol samples could be traced to the irrigation water.
Saliva contributed very little. The median contribution was zero.
Low levels of the virus were found in the saliva of several patients who had no symptoms, but none was found in the aerosols from their procedures.
The authors concluded that, with standard infection-control measures such as a mouth rinse before treatment and high-volume suction, dental treatment did not appear to increase the risk of passing the virus from patients without symptoms.
What are the limits?
It was one center and 28 patients.
It measured where microbes landed, not whether anyone became infected.
It did not address the spread of a virus through talking, coughing or sneezing in a waiting room or treatment room, which the lead author noted still carries risk.
The results apply to treatment done with the precautions the study used.
What does it mean now?
This study is part of the record of how dentistry responded during the pandemic. Its main lesson still holds: routine infection control, including clean water lines, suction and barrier protection, is what limits the spread of germs in a dental office.
If you have a health condition that affects your immune system and have questions about dental visits, tell us when you schedule. You can read more about dental care for people with complex medical needs. Patients in Jacksonville can contact our office with any questions before a visit.
Sources
Meethil AP, Saraswat S, Chaudhary PP, Dabdoub SM, Kumar PS. Sources of SARS-CoV-2 and other microorganisms in dental aerosols. J Dent Res. 2021;100(8):817-823. doi:10.1177/00220345211015948. Retrieved via PubMed.
Ohio State University. Press release on dental aerosols and COVID-19, May 2021.
About the author. CJ Henley, DMD, is a general dentist in Jacksonville whose practice focuses on cosmetic and restorative dentistry, dental implants and dental care around head and neck cancer. Meet Dr. Henley.
CJ Henley, DMD, PA · 3675 Hendricks Avenue, Jacksonville, FL 32207 · 904-398-1549
Updated October 2026.