齿合度（denticity）是一个配位化学的名词，是指在错合物中，单一配体和中心原子产生键结的原子个数。

通常配体只有一个原子和中心原子键结，因此齿合度为1，这种的配体也称为单齿配体。双齿配体（如草酸根、乙二胺）有二个原子和中心原子键结，齿合度为2。EDTA由六个不同的原子和中心原子键结，因此EDTA为六齿配体，齿合度为6。

齿合度的英文名称denticity和dentist（牙医）有相同表示牙齿的字根。齿合度可以想成是配体以一个点或多个点「咬住」中心原子。

齿合度和哈普托数（hapticity）不同，后者是在配体不是单一原子和中心原子键结的情形下，配体参与和中心原子键结的电子数。

Denticity refers to the number of donor groups in a single ligand that bind to a central atom in a coordination complex. In many cases, only one atom in the ligand binds to the metal, so the denticity equals one, and the ligand is said to be monodentate (sometimes called unidentate). Ligands with more than one bonded atom are called polydentate or multidentate. The word denticity is derived from dentis, the Latin word for tooth. The ligand is thought of as biting the metal at one or more linkage points. The denticity of a ligand is described with the Greek letter κ ('kappa'). For example, κ-EDTA describes an EDTA ligand that coordinates through 6 non-contiguous atoms.