Patients will receive an intensive (non surgical) regimen of scaling and root planing of the root surfaces under local analgesia (depending on the severity in one session or two sessions within 2 days). Any tooth that from the baseline examination is defined as hopeless or irrational to treat will be extracted at the oral hygiene visit. After the 2 months re-assessment individuals if presenting with at least one periodontal pocket of 6 mm in depth will undergo additional corrective periodontal therapy consisting of periodontal surgery and re-instrumentation under local analgesia. If surgical periodontal therapy is not indicated, appropriate re-instrumentation of the sites will be performed.

Patients will receive an intensive (non surgical) regimen of scaling and root planing of the root surfaces under local analgesia (depending on the severity in one session or two sessions within 2 days). Any tooth that from the baseline examination is defined as hopeless or irrational to treat will be extracted at the oral hygiene visit. After the 2 months re-assessment individuals if presenting with at least one periodontal pocket of 6 mm in depth will undergo additional corrective periodontal therapy consisting of periodontal surgery and re-instrumentation under local analgesia. If surgical periodontal therapy is not indicated, appropriate re-instrumentation of the sites will be performed.

CvR to hypercapnia was evaluated by means of the breath-holding index (BHI). Two dual 2-MHz transducers fitted on a headband and placed on the temporal bone windows were used to obtain a bilateral continuous measurement of mean flow velocity in the middle cerebral arteries. Depth of insonation ranged from 48 to 52 mm. The BHI is obtained by dividing the percentage increase in mean flow velocity occurring during breath holding by the length of time (seconds) subjects hold their breath af- ter a normal inspiration ([mean flow velocity at the end of breath holding minus mean flow velocity at rest divided by mean flow velocity at rest] multipled by 100 divided by seconds of breath holding).

Gosling's pulsatility index (PI) of the middle cerebral artery will be calculated according to the following formula: PI = (Vmax -Vmin)/Vmean