canal is affected, with vertical nystagmus ( up-down eye movement ) the superior ( also called anterior ) canal is affected, and with diagonal nystagmus ( diagonal or rotational eye movement ) the posterior canal is affected. Diagonal eye movement is easily confused with horizontal movement. This is important since it might result in selecting a wrong and thus ineffective cure maneuver. In rare cases, the crystals themselves can adhere to a semicircular canal cupula, rendering it heavier than the surrounding endolymph. Upon reorientation of the head relative to gravity, the cupula is weighted down by the dense particles, thereby inducing an immediate and sustained excitation of semicircular canal afferent nerves. This condition is termed cupulolithiasis. There is evidence in the dental literature that malleting of an osteotome during closed sinus floor elevation, otherwise known as osteotome sinus elevation or lift, transmits percussive and vibratory forces capable of detaching otoliths from their normal location and thereby leading to the symptoms of BPPV. BPPV can be triggered by any action that stimulates the posterior semi-circular canal including: Looking up or down Following head injury Sudden head movement Rolling over in bed Tilting the head BPPV may be made worse by any number of modifiers which may vary among individuals: Changes in barometric pressure – people may feel increased symptoms up to two days before rain or snow Lack of sleep (required amounts of sleep may vary widely) Stress An episode of BPPV may be triggered by dehydration, such as that caused by diarrhea. For this reason, it commonly occurs in people with post-operative diarrhea induced by post-operative antibiotics. BPPV is one of the most common vestibular disorders in people presenting with dizziness; a migraine is implicated in idiopathic cases. Proposed mechanisms linking the two are genetic factors and vascular damage to the labyrinth. Although BPPV can occur at any age, it is most often seen in people older than the age of 60. Besides aging, there are no major risk factors known for BPPV, although previous episodes of head trauma, or the inner ear infection labyrinthitis, may predispose to the future development of BPPV. Mechanism The inside of the ear is composed of an organ called the vestibular labyrinth. The vestibular labyrinth includes three semicircular canals, which contain fluids and fine hairlike sensors that act as a monitor to the rotations of the head. Other important structures in the inner ear