data source: American Dental Association, Health Policy Institute

In 2020-21, 57% of the nearly 11,000 applicants to dental school enrolled in the 66 dental schools in the United States and Puerto Rico. Decreasing applications and increasing 1^st year positions made for a relatively favorable environment for applicants.  Before exploring the present day, let’s take a brief look at the last 70 years in dental education.

1950 to 1975: EXPANSION

Following World War II, dental education saw an unparalleled expansion for 30 straight years.  A rapidly growing population led to the perception that there was a shortage of health care providers including dentists. ^{1 2}

This led the federal government to give hundreds of millions of dollars to dental schools.³  They passed 2 different acts (Health Professions Educational Assistance Act, 1963 and The Comprehensive Health Manpower Act, 1971) that gave $786 million in federal aid to dental education between 1965 and 1981. ^{3 4} Construction grants contributed to the building of 13 new dental schools and the renovation of 34 existing schools.  Additional grant money was provided to schools that expanded their class size.⁴  In the mid to late 1970’s, applications rose to a level that has not been seen since and enrollment rose to a level that was only surpassed a few years ago.

1975 to 1990: OVERSUPPLY of DENTISTS…CONTRACTION

The population leveled off in the 1970’s and there was a recession in the early 1980’s.⁴  Equally important was a widespread belief that fluoridation had caused a decrease for the demand of dentistry.³ When the Federal subsidies ended in 1981, dental schools were forced to compensate with increased tuition.³  A perceived shortage of dentists had now turned into an oversupply of dentists.

Over the next decade and a half, dental school applications dropped by more than 2/3. Applications plummeted from more than 15,000 people to less than 5000.  There was a corresponding drop in enrollment from over 6300 to less than 4000.  Many schools contracted in size in response to an increasingly poor applicant pool.³  Six private dental schools closed in the late 1980's and early 1990's.

1990-2021

The last 30 years have seen new schools open and enrollment increase.  13 new dental schools have opened with only 1 closure.  While applications generally rose in the 1990s and early 2000’s, they have been declining almost every year since 2007.

What does this mean for aspiring dentists?  The number of available 1^st year positions is currently at an all-time high.  Enrollment should continue to rise and new schools are poised to open (Texas Tech matriculated its first class in 2021-22). Applications, although relatively high in a historical context, have been declining for almost 15 years.  This is no doubt in response to an increased concern of high tuition and the corresponding student loan debt that dental students graduate with.

57% of applicants were accepted in the 2020-21 cycle.  This number has been on the rise every single year since 2007, when less than 35% of applicants were accepted. We have every reason to believe that it will continue to get easier to be accepted to dental school in the coming years.  Dental schools continue to open and 1^st year enrollment continues to rise.  As greater attention is placed on the financial burden of attending dental school, potential applicants may seek other professional paths.  For those seeking admission to dental school, it makes for a very friendly environment.

We are revisiting the American Dental Association Health Policy Institute’s Covid-19 Economic Impact poll.  This tracking poll began in March 2020 to access the impact Covid-19 has had on practicing dentists.  In each wave (biweekly in 2020, monthly in 2021), 4 core questions were consistently asked to participating dentists.  We are now 1 year and 23 waves into the tracking poll.  In this post, we will take an updated look to see how each state is performing.  We will also explore the rural-urban divide that the data has consistently shown to exist.

For a more detailed breakdown of the poll, please see our initial post.

The dental industry is recovering

In the first plot (Fig. 1), we look at the question, ‘What is the current status of your dental practice?’.  The percent of dentists who responded, ‘Open and business as usual’ is used as our metric.  An Exponential Moving Average (EMA) was calculated for each state to smooth the data and mitigate small sample size.  In the most recent wave (March 2021), 18 states currently have their highest EMA, with another 7 states having their 2^nd highest EMA.  March 2021 is the highest performing wave since September 2020.

In the next plot (Fig. 2), we look at the question of 'Patient Volume' and 'Total Collections'. Dentists were asked to select from 6 numerical categories to quantify how they were doing that wave compared to a typical week in their practice.  The results for ‘Patient Volume’ and ‘Total Collections’ tracked each other extremely closely, so they were averaged together.  Again, an EMA was calculated for each state.  In the most recent wave (March 2021), 36 states currently have their highest EMA.  In regard to 'Patient Volume'/'Total Collections', states are clearly performing the best they have at anytime during Covid-19.

Rural-Urban divide

In the last plot (Fig. 3), we explore how geography affected the results.  Each dentist respondent was placed into 1 of 4 geographical categories: Rural, Suburban, Urban, and Top 20 City.  The breakdown of each state in regard to the geography variable can be seen in the left panel.  As with the previous plots, we explored the questions, ‘What is the current status of your dental practice’ and ‘% of normal Patient Volume/Total Collections’. The top panel looks at results from all 50 states and D.C..  The middle panel looks at only the 13 states that have a ‘Top 20 City’.  A clear trend can be seen where rural dentists performed the best, with suburban dentists following.  Urban and Top 20 City dentists consistently performed the worst in the tracking poll.

The bottom panel looks at each state’s results individually.  The states are sorted from most Urban to most Rural according to FiveThirtyEight’s Urbanization Index (UI).  The UI calculates the average number of people living within a 5-mile radius of each census tract within a state in an effort to quantify how rural or urban a state is.  The best performing states are overwhelmingly rural.  The most urban states almost uniformly performed poorly.  Rural dentists consistently outperformed their colleagues.

Group the 50 states + D.C. into tiers based on their recovery during the fall and winter

Data: A.D.A. Health Policy Institute Covid-19 tracking poll

Dates: September 21^st to December 14th.  This encompasses the most recent 7 waves (14-20) of the bi-weekly tracking poll.  The wording of certain questions was changed in-between waves 13 and 14 so this is a convenient starting date.

Method: average each state’s performance in the 4 main questions of the tracking poll over the last 7 waves.  K-means clustering was used to find the appropriate number of clusters/tiers with-in the data.  This is a form of unsupervised machine learning.  For further analysis on Clustering method, please see Elbow Method and Silhouette Method plots in footnote.

Results: 4 tiers were found within the 50 states + D.C.

*a primer on the A.D.A.’s tracking poll can be read here

Tier 1 (14 states)- all about the Southeast and Midwest

This tier is dominated by the Southeast and Midwest.  In our earlier exploration of the H.P.I.’s tracking poll, these 2 regions were found to be the best performing, so this is no surprise.  10 of the 14 states in this top tier reside in the Southeast (6) and Midwest (4).  Three Western states (Utah, Idaho, Montana) made the top tier despite this region not performing well overall.

The results of the smaller states (less responses in the tracking poll…smaller sample sizes) always need to be viewed with caution. The geographic proximity of these 3 West states lends itself to the belief that this truly is a well performing pocket within the West.  The lone Northeast state to make this top tier is Maine.  Maine’s small sample size and significantly better results than all other states within the Northeast create skepticism to the true strength of it’s results.

Tier 2 (12 states)- more Southeast and Midwest

This second tier is also dominated by the Southeast and Midwest.  8 of the 12 states in this 2^ndtier reside in the Southeast (3) and Midwest (5). The lone West state (Washington) and Southwest state (Arizona) to crack this 2^nd tier share borders with the highly performing West states from the top tier.  The Northeast states of Rhode Island and Delaware made this top tier.  Rhode Island and Delaware (along with Maine in the 1^st tier) are certainly outliers within their regions.  Their small sample sizes are prone to statistical noise.

Tier 3 (19 states)- all about the Northeast and West

The largest tier is comprised of states that have faired poorly but have done distinctly better than the bottom tier.  This tier is dominated by the Northeast and West. 8 of the 12 Northeast states reside in this below average tier.  Of note, the 3 of the 4 largest states are in this tier (New York, Texas, Florida).

Tier 4 (6 states)- the West

This bottom tier had a significant drop off from tier 3.  These 6 states have faired very poorly in their recovery over the fall and winter.  Half of this tier is comprised of West states: the most populous California along with the non-contiguous states of Alaska and Hawaii.

Footnote:  Elbow Method plot and Silhouette Method plot

On March 16, 2020, the American Dental Association took an unprecedented step and recommended that all dentists immediately postpone all elective and non-emergent services for a minimum of 3 weeks. On April 1^st, the A.D.A. extended that recommendation until April 30^th.  These were recommendations, not mandates, and were made on the national level.  The decisions to allow dentists to re-open for elective procedures were made on the state level, with Alaska becoming the first to do so on April 20^th.  Over the next 6 weeks, states would continue to allow their dentists to re-open for elective procedures, with Massachusetts being the last on June 8^th.

The A.D.A. began to survey dentists the week of March 23^rd to understand the impact Covid-19 was having on the profession.  This survey, conducted by the A.D.A.’s Health Policy Institute (H.P.I.), was sent out as a biweekly poll to its nearly 70,000 members.  The same four questions were repeatedly asked every 2 weeks, serving as a tracking poll that could be analyzed on a national, regional, or state basis. Nine months later, we now have 20 waves of data that we can dissect. We will analyze these 4 questions to see what can be learned from this unique tracking poll. Particular attention will be given to the 1^st question as it proved to be the most informative.  I contacted the H.P.I. multiple times requesting more specific data or a clarification on their methods and they were transparent and forthcoming in every exchange.

The 1^st question, “What is the current status of your dental practice?”, provides us the most insight as to how the dental profession has been faring over the last eight months.  Two months into the pandemic (May 18^th), just 10.8% of dentists reported being ‘Open and business as usual’ (Fig. 1). One month later, 33.8% responded favorably.  By the middle of the summer (July 13^th), that number rose to 41.6%, and continued to rise as the summer progressed, peaking at north of 48% by the end of August and early September.  The fall has brought a slow and steady decline, dropping to just 32.4% of dentists reporting being ‘Open and business as usual’ in the penultimate wave.  The most recent wave showed a moderate uptick (38.5%) that would prove notable if enduring. Only 21 states ever reached 60% in a single wave.  Less than half the states (24) reached 55% in two separate waves. Montana served as the high-water mark recording 85% in late August.  The states are colored according to their geographical region.

The 2nd question, "Is your dental practice paying staff this week?", proved to be much less informative.  Since mid-June, when all states had officially re-opened for elective procedures, only 10 states have averaged below 90% regarding fully paying their staff (Fig. 2).  16 states have averaged 95% or more.  During this same period, only 14 states have fallen below 80% in a single wave.  This should be viewed as a positive that despite a downturn in other metrics, dental offices overwhelmingly still have the financial solvency to continue to pay their staff. However, this metric is too inelastic to serve as a barometer for how the dental profession is currently faring.  With nearly all states north of 90 percent, couples with the small sample size, insights could not be made from this question.

The 3rd and 4th questions asked dentists to categorize their current patient volume and volume of collections into one of six numerical categories ranging from 0 to 100%. For both questions, the H.P.I. changed the answer choices between the 13th and 14th wave (mid-Sept) from being negatively skewed to being positively skewed.  The survey went from having three of size answer choices parse different levels of below 25% of patients/collections (<5%, 5-10%, 11-24%) to having three of the six answer choices parse different levels of above 75% (76-85%, 86-95%, >95%).  When asked for comment on why they changed the answer selections, the H.P.I. responded that it was in response to economic conditions in practices improving.  While conditions had been improving each subsequent wave from April through September, those improvements were decreasing in size.  A more honest evaluation of the data would have more likely shown a plateau at this time.  Armed with the knowledge of rising Covid-19 cases as the fall transitioned to the winter, a decline could have been reasonably expected.  I do not think this change in answers was justified.  Both questions received an artificial boost from the more positive framing.  This is highlighted visually by a discontinuity between waves 13 and 14 (Fig. 3, Fig. 4).  49 of the 50 states and D.C. showed an increase in the percentage of dentists reporting at least 75% of patient volume from wave 13 to wave 14.  The average state had an increase of over 14% in dentists reporting to be above 75%.  A similar phenomenon can be seen with the collection data: 49 of 50 states and D.C. increased from wave 13 to wave 14, with an average increase of over 15%.  When all four questions are plotted together (Fig. 5), it is clear that the last 2 questions received an artificial boost from the more positive framing.  This increase is discordant with the data from the first 2 questions.

Let’s re-examine the 1^st question using the visual of a heat map as an aid.  The 50 states and D.C. are sorted alphabetically. This heat map shows the percentage of dentists reporting being ‘Open and business as usual’ for each of the 19 waves in the H.P.I.’s tracking poll (Fig. 6). The range of values go from 0 to 85%. You can see the stark darkness of April and May. Other than this, not much can be gleamed from this heat map.  Because of the near complete shutdown in April and May, the range of values is too large for a more discerning analysis of the more recent results.  As you can see in the dot plot (Fig. 7), after the initial shutdown, the majority of results have fallen in the range between 30 and 70%.  This is the range we are going to focus on moving forward.  Visually, this means that 15% will appear the same as 30%, as will 85% appear the same as 70%.  More importantly, the difference between 30%, 50% and 70% will be more vivid.  This is our intention.

The next heat map adapts that adjusted scale (30-70%) and orders the states by their population (Fig. 8).  When looking at this plot, there are 3 main takeaways.

· the largest states have done relatively poorly. Five (California, Texas, New York, Florida, Pennsylvania) of the six largest states are in the bottom 18 in recovery.  This was calculated by taking the mean for each state from wave 7 (mid-June, when all states were re-opened) to the most recent wave. The only exception was Illinois, which showed a slightly above average recovery (22^nd best).

· some of the smallest states have shown the best recovery. Of the 9 states that have shown the best recovery, 4 are particularly small states (Montana, South Dakota, Idaho, North Dakota).

· Beginning with wave 7 (when all states were officially re-open), we calculated the 8-week rolling average for each state.  13 states currently have their worst 8 week rolling average since the initial shutdown. 27 other states currently have their 2^nd worst 8 week rolling average.  Despite poor conditions for the last 6 months, the most recent 8-week stretch has been at a worst or near-worst level for the overwhelming majority of states. Although the most recent wave showed some optimism, it is unlikely this upward trend will continue as the winter progresses.

In this next heat map (Fig. 9), the states are faceted into 5 geographical regions (Northeast, Midwest, Southeast, Southwest and West). This allows us to explore for any regional trends that have occurred across our country.  In this regional exploration, each state’s ‘Dental Footprint’ was calculated to ascertain how much weight each state should be given relative to every other state (Fig. 10). The ‘Dental Footprint’ gave equal weight to three variables on the state level: population, number of dentists, and number of survey respondents. This best captures each state’s contribution from a public health (population) and industry (number of dentists) perspective while also giving weight to states that had more survey participants. For example, in comparing California to Wyoming, California has 67x the population, 97x the number of dentists and 40x the number of survey respondents.  Correspondingly, California has a Dental Footprint that is 63x as large as Wyoming.  In moving from Figure 9 to Figure 11, we scaled each state’s height to correspond to their ‘Dental Footprint’. Figure 11 highlights the vast discrepancy between state's dental footprints. The oversized weight that states such as California, Texas, New York and Florida have compared to some of the smaller states is very apparent.

Of the nearly 70,000 A.D.A members invited to participate in this tracking poll, over 19,000 responded to the first survey.  That number would quickly drop to roughly 6000 by the second survey and just over 2700 in the most recent wave. In this most recent wave, 25 states had less than 30 dentists respond to the survey. This diminished sample size created too much noise and made the bi-weekly results of the smaller states too unreliable.  To correct for this noise, we aggregated together states within each region that had an insufficiently large ‘Dental Footprint’. The cutoff was made at 2%.  States that had greater than a 2% ‘Dental Footprint’ were able to be analyzed on their own.  States that fell below that threshold were aggregated together with their fellow smaller states within their region.  An effort was made to aggregate states together that were geographically closest to each other.  Upon aggregation, each state’s dental footprint was used to give them proper weight in their aggregation. Figure 12 shows this aggregation, now dividing the country into 30 sub-regions.  Each sub-region comprised at least 2% and was large enough to be analyzed accurately. In analyzing Figure 12, we see

· the Northeast, West and Southwest have been hit the hardest.  Since the initial shutdown, the Northeast (35.7%) and West (36.3%) have been hit the hardest, with the Southwest fairing slightly better (39.6%). The Northeast faired uniformly poorly, with no sub-region topping 41%. The West was more of a mixed bag.  The sub-region of Utah-Idaho-Montana-Wyoming did remarkably well (56.8%) but was weighed down by the outsized effect of poorly performing California (31.3%).  The Southwest was also uniformly poor, with no sub-region topping 43%.

· the Southeast and Midwest have shown the strongest recovery. The Southeast (46.2%) and Midwest (47.5%) have demonstrated the strongest recoveries since the initial shutdown. The Southeast’s largest state, Florida, faired poorly (37.6%). The other 5 sub-regions within this region all did significantly better, all averaging above 44%.  The Midwest, with the exception of Ohio and Minnesota, has also shown a strong recovery. The Midwest’s other 6 sub-regions all averaged above 46%.

The H.P.I. recently announced that as the calendar year turns to 2021, they will be moving their tracking poll from bi-weekly to monthly.  We will continue to report on the results to better understand how Covid-19 is affecting the dental industry.