Sir,- In response to the letter of B. Skinner (BDJ2003; 195: 231) I have also noted the increase in calculus formation in patients on high protein diets such as the Atkins diet. I have a relatively high proportion of vegetarians in my practice and in contrast these patients produce little if any calculus.
Part of my clinical examination includes the measurement of saliva pH and as a generalisation vegetarians have an alkaline pH of 7-8.5 whilst the patients on high protein diets are around the 6-6.5 range unless they are taking supplements to compensate for the stress of a high protein diet. I suspect that the answer to this lies in the body's reaction to acideamia.
If the body becomes acidic it will bring into action the buffering systems, one of which is the phosphate system. To make phosphate available the body will break down bone and release both calcium and phosphate. If the blood has an increased concentration of free calcium and phospate then so will the saliva. A combination of free calcium, phosphate and a pH of 6-6.5 in the saliva will encourage calculus formation.
