10 February 1949 Tolkien writes to Douglas Veale, the Oxford University Registrar. He asks how he should present a request for a period of leave (including Trinity Term), and points out that in all his years as a professor he has had no leave except for an emergency' fortnight a year earlier on medical grounds. 'Apart from the minor medical object of having all my teeth, which are said to be poisoning me, removed, my main object would be to complete a number of writings I have on hand' (Oxford University Archives FA 9/2/875).
20 March 1948 Tolkien writes a letter to Mabel Day of the Early English Text Society, who apparently has written to ask what progress he has made on the Ancrene Wisse. He tells her he has 'been unwell for some time, espec[ially] since October, and though X-ray exams revealed nothing immediately serious beyond 19 poisonous teeth, I was obliged, for the first time, to take part of last term off and go away. I still feel far from well, though possibly if I can find time and money for the removal of all my teeth, I may improve. They are said at any rate to account for perhaps 10% of my debility!'
9 March 1950 Tolkien begins to have his diseased teeth removed.
10 March 1950 Tolkien replies to Stanley Unwin's suggestion of 6 March. [....]'I have not at the moment anything else completed to submit; but I am quite prepared to make something simpler and shorter soon. I feel, at the end of my leave of absence, a return of energy, and when the present time of trial is over (the process of removing all my teeth began yesterday, and that of removing my household goods begins shortly) I hope to feel still more'(Letters, p. 138).
4 April 1950 In the morning, Tolkien rings Warnie Lewis and asks him to meet at the 'Bird and Baby' after Tolkien has visited his dentist to be fitted with a set of false teeth.
14 April 1950 Tolkien drafts a reply to Stanley Unwin's letter of 3 April. [....] He then writes a less confrontational letter, [...]. He apologizes for his delay in replying: 'I have been troubled by dentist and doctors since you wrote. I do not yet know the full report of the specialist and X-ray; but I gather that my throat is in a bad way. Still when all my teeth are at last out (four more went today) it may improve a little, and I may hope to escape any immediate operation. That is at any rate a more cheerful prospect than I had begun to envisage' (Tolkien-George Allen & Unwin archive, HarperCollins; partly printed in Letters, p. 141).