Bacteraemia Secondary to Tooth Extraction: a Randomized Clinical Trial on Efficacy of Three Different Chlorhexidine Prophylaxis Protocols

The study group will be formed of patients undergoing tooth extraction under local anaesthesia in the Department of Stomatology and Maxillofacial Surgery of the Santo Antonio General Hospital (Oporto, Portugal).The following exclusion criteria will be applied: patients under 18 years of age; antibiotic treatment in the previous three months; routine use of oral antiseptics; and any type of congenital or acquired immunodeficiency or other disease that can favour the onset of infection or haemorrhagic complications. Applying these criteria and after a statistic power test, the sample will be 208 patients. The select patients will be attributed randomly a number of participation and they will be distributed into four groups:

• Control Group: 52 patients who will use no prophylactic chlorhexidine (CHX) regimen.
• CHX mouthwash group (CHX-MW group): 52 patients who will perform a mouthwash with 0.2% CHX (10 ml for 1 minute, BSAC recommendations) (Oraldine Perio®, Johnson and Johnson, Barcelona, Spain) before the tooth extraction.
• CHX mouthwash/subgingival irrigation group (CHX-MW/SUB_IR group): 52 patients who will perform a mouthwash with 0.2% CHX (10 ml for 1 minute) (Oraldine Perio®) and who then will undergo subgingival irrigation with 1% CHX on the tooth to be extracted; the irrigation will be done with the Heraeus Citojet Intraligamental Syringe (CIS) (Kulzer Heraeus S.A., Madrid, Spain) at six points on each tooth (3 points on the vestibular surface and 3 on the palatine surface).
• CHX mouthwash/supragingival irrigation group (CHX-MW/SUPRA_IR group): 52 patients who will perform a mouthwash with 0.2% CHX (10 ml for 1 minute) (Oraldine Perio®) and who then will undergo supragingival irrigation with 1% CHX on the tooth to be extracted; the irrigation will be done continuously around the tooth to be extracted by a conventional syringe.

The mouthwash and subgingival or supragingival irrigation will be performed before injection of the local anaesthetic.

After recording the sex and age of each patient, a single dentist will perform an intraoral examination 2 days before the intervention, collecting the following information: plaque deposits (simplified Greene and Vermillion oral hygiene index) , calculus deposits (Ramfjord calculus index), presence of gingival bleeding (Löe and Silness gingival index), depth of periodontal pockets (Ramfjord index), degree of tooth mobility (Ramfjord tooth mobility index), number of caries (including root remnants), and presence of submucosal abscesses, fistulae and periapical foci detected clinically and/or radiologically. Each patient will be assigned an overall oral health status using a scale designed by the authors and published previously; the scale incorporates dental and periodontal health criteria.

Local anaesthesia will be administered to all patients using conventional techniques (regional block and/or infiltration). The anaesthetic will be lidocaine plus adrenaline (1:100,000) and not more than 2 cartridges in any patient.