Molly Thynne's Death in the Dentist's Chair (1932) anticipated Agatha Christie's One, Two, Buckle My Shoe (1940), which memorably has Hercule Poirot walk into a baffling murder problem at the dentist's office, by eight years. Aside from these two "dentist mysteries" I know of one other, of much more recent vintage: M. C. Beaton's Death of a Dentist (1997), which I have yet to read.
I think the idea of murder at the dentist's office is a natural notion for a mystery writer, because for a lot of us this is a fearful locale to start with, right? Christie's American publishers evidently found the Crime Queen's nursery rhyme title unenticing, at various times retitling the novel The Patriotic Murders and An Overdose of Death, though neither title really takes advantage of the inspired initial setting of the dentist's office.
"All the upper incisors," he assented cheerfully, "eight altogether. They came out beautifully. Like to see them?"
As poorly as poor Mr. Cattistock feels after Davenport's deed, the dentist's next patient, one Mrs. Miller, comes out much worse: she is found dead in the dentist's chair, her throat viciously cut. The dentist claims that after briefly leaving his (living) patent he found the door locked upon his return (locked room enthusiasts don't get excited; the room has an unfastened window), but is he telling the truth?
Or, on the other hand, could any of the patients in the office at the time--little Mr. Cattistock, lovely Mrs. Vallon or Sir Richard Pomfrey--have had a hand in the affair? Or was the murder an outside job?
Death in the Dentist's Chair offers vintage mystery fans a pleasingly intricate murder problem that keeps those little grey cells clicking and I enjoyed it immensely.
Contemporary crime fiction reviewer Charles Williams was a fan of the Dr. Constantine mysteries too, declaring that the amateur sleuth "deserves to be known with the Frenches and the Fortunes" (referencing Freeman Wills Crofts' Inspector French and H. C. Bailey's Reggie Fortune).
It's just too bad that only three of his cases ever were recorded (the final Dr. Constantine mystery is He Dies and Makes No Sign, 1933), but happily all three soon will be back in print.