FUNDAMENTALS OF IMPLANT IMAGING

Oral cancer is the sixth most common malignancy with almost 500000 new cases reported worldwide annually. The diagnosis of oral cancer at an early stage has a good prognosis as the survival rate is high (around 80%). However, the majority of oral cancer cases are diagnosed at a later stage with a considerably poor 5-year survival rate of 50% according to World Health Organization statistics. Thus, an effective management strategy for oral cancer will depend on its early identification and intervention which would pave the way for superior prognosi

A better device is the triac, bidirectional thyristor, which allows the full a.c. power to be controlled. It comprises two thyristors connected in parallel and working in opposition but controlled by the same gate. The trigger pulses to a triac are provided by a special device called diac, bidirectional breakdown diode. It is, in effect, two Zener diodes connected back to back. The diac conducts in either direction if the applied voltage reaches the breakdown voltage of about 30 V. This