H.—3l.

In addition to these new centres, the following existing centres were reinforced by the appointment of additional staff: Alexandra, Birkenhead, Ellerslie, Henderson, Invercai'gill, Sandringham, Wliangarci Country. Forty-two new clinics have been authorized at centres which were not served before, and eight existing centres are to be reorganized in the immediate future, and their scope extended by the appointment of additional staff. Details of these are given in another section of this report. To facilitate the control of the ever-increasing number of clinics, the dental districts have been further reorganized by including the Taranaki Health District in the Wellington Dental District, instead of in the South Auckland Dental District as it was originally. The Principal Dental Officer, in addition to his duties at Head Office, retains control in the meantime of a small district comprising the Manawatu, Hutt Valley, and Marlborough areas. This has been designated, for the present, the " Inner Wellington District." Statistics. Operations performed in the field and in the training-school from Ist January to 31st December, 1939 :— Fillings— In permanent teeth .. .. .. .. .. 281,104 In deciduous teeth .. .. .. .. .. 334, 410 ——- 615,514 Extractions — In permanent teeth .. . . . . . . . . 2,954 In deciduous teeth .. .. .. .. .. 73,039 — 75,993 The following figures illustrate the progress made during the last 10 years : —

Total number of operations since the inception of the service, 8,463,189. Ratio of Extractions to Filling,s. The number of teeth extracted as unsaveable as compared with the number of fillings performed shows a small increase on this occasion, to the extent of 0-4 extractions per 100 fillings. This is accountable for by the number of new clinics opened, and the corresponding increase in the number of new entrants, as the latter invariably require a certain number of extractions. The figure for the year under review is 12-3 extractions per 100 fillings. The following table shows the ratio of extractions to fillings since the inception of the service

The above figures include both permanent and deciduous teeth. For permanent teeth alone the ratio is 1-05 extractions per 100 fillings.

45

Number of Schools ' Number of Children 1 ,,, , , „ , ( Year. ' under Systematic ! receiving Systematic ! °,? u ,"' er ° Treatment.. ! Treatment. Operations. _ __ j jy— 1930 .. .. .. .. 930 67,652 ! 463,204 1931 .. .. .. .. 1,180 68,995 562,759 1932 .. .. .. 1,297 72,584 i 619,390 1933 .. .. .. .. 1,430 78,391 623,625 1934 .. .. .. .. 1,551 83,433 626,878 1935 .. .. .. 1,590 84,738 674,374 1936 .. .. .. .. 1,629 89,803 725,609 1937 .. .. .. .. 1,568 89,483 759,873 1938 .. .. .. .. 1,620 94,261 826,598 1939 .. .. .. .. 1,749 101,701 912,370

Fillings. Extractions. Rat *° : ?"j. ons 6 per Hundred Killings, 1921-22 .. .. .. 13,047 14,939 114-5 1922-23 .. .. .. 24,603 25,436 103-3 1923-24 .. .. .. .. 47,610 37,978 79-7 1924-25 .. .. .. .. 59,322 43,181 72-6 1925-26 .. .. .. 61,506 41,339 67-2 1926-27 .. .. .. .. 84,723 53,232 62-8 1927-28 .. .. .. 116,916 66,523 56-8 1928-29 .. .. .. .. 146,354 76,555 52-3 1929-30 .. .. .. .. 190,934 71,128 37-2 1930-31 .. .. .. .. 258,546 75,973 25-5 1931-32 .. .. .. .. 334,827 80,389 24-0 1932-33 .. .. .. .. 382,389 74,633 19-5 1933-34 .. .. .. .. 397,437 69,208 17-4 1934-35 .. .. .. .. 399,560 70,207 17-5 1935-36 .. .. .. .. 450,727 72,782 16-1 1936-37 .. .. .. .. 498,121 72,088 14-6 1937-38 .. .. .. .. 535,441 68,832 12-9 1938-39 .. .. .. .. 571,199 67,972 11-9 1939-40 .. .. .. .. 615,514 75,993 12-3