This 30 year old patient drinks lemon water all day long. She also grinds her teeth. The grinding causes her teeth to crack and the acid from the lemon juice erodes the tooth causing demineralization of enamel allowing tooth decay.
Next, his 23 year old patient had a crack in his back upper molar. The tooth had a 10 year old amalgam restoration in it. The crack allowed decay to spread deep under the old amalgam filling. The tooth was not sensitive and the patient was unaware that he had a cavity. I removed the old filling and cleaned up the decay, placed a fluoride base to protect the pulp and restored the tooth with a beautiful ceramic composite.