Dental supplies maker Dentsply Sirona shares dropped on Tuesday after the company cut its earnings and revenue estimates for 2018, citing destocking from partner dealers.

Shares tanked 18.7 percent at $39.41 per share, the stock's worst day in over five years, after the company announced that it expects earnings of $2.00 to $2.15 per share for 2018, down from its previous forecast of $2.55 to $2.65. The company said it expects revenue for the year to decline 2 percent as a result of inventory destocking by partners who sell Dentsply Sirona products.

The dental supplies manufacturer also reported second-quarter earnings of 60 cents per share, slightly better than an expected 58 cents by a consensus of analysts, according to Thomson Reuters, but five cents per share below earnings from the same quarter last year. Revenue for the quarter was $1.04 billion, also just above consensus estimates.

"We are clearly not satisfied with our performance," said CEO Don Casey in the release. "Our global management team is in the middle of an extensive review of the business and is putting together a comprehensive restructuring program."

Casey said the restructuring program will include aggressive cost containment and simplification of the organization.

The stock was already down about 20 percent through Monday's close.