Health chiefs say they are not concerned about a surprise drop in the amount of work carried out by NHS dentists in London.
The number of Units of Dental Activity (UDA) has gone into decline in the capital after rising consistently for many years, a dentistry analysis shows.
In the second quarter of the last financial year between July and September 2013 there were 2,988,000 UDAs, according to the Health and Social Care information Centre (HSCIC).
This was a 2.7% fall on the total recorded in the same quarter of the previous year, 2012-13, when the figure was 3,070,000.
London experienced a much sharper decline than anywhere else in England, where the number of UDAs was either flat, or fell by no more than 0.5%.
And the drop followed a decline between July and September 2011 and July and September 2012, from 3,114,000 UDAs, or 1.4%.
Furthermore, the twin falls came after many years of rising activity since at least 2008-09 (2,765,000) and through 2009-10 (2,998,000), 2010-11 (3,091,000) and into 2011-12 (3,114,000).
Each statistic is for the second quarter (Q2) of each financial year, in regular bulletins issued by the HSCIC.
Asked about the pattern, NHS England, which commissions dental services, disputed that it meant the capital was on a 'downward trend'.
And it argued the number of UDAs was not a guide to the amount of treatment carried out, despite it being the measure used to pay dentists and set contracts.
An NHS England spokesman said: 'Whilst we cannot dispute that the data would suggest a reduction in activity in recent years being delivered at a comparable point (Q2), it is important to note that the delivery of the dental contract in primary care is across a 12 month period.
'Looking at a point in isolation is not necessarily a reflection of a downward trend.
'The number of UDAs delivered does not represent a direct correlation with the number of treatments, given that treatments vary in complexity and number of UDAs claimed.
'The performance of primary care providers of NHS Dentistry is monitored closely by NHS England.'
Across England, the total number of UDAs fell slightly in the second quarter of 2013-14, from 21,692,000 to 21,559,000 a decline of 0.6%.
But the number of band one UDAs actually rose by 145,905, or 2.7%, the figures showed.