Efficacy of repeated immersion of maxillary acrylic dental prostheses in sodium hypochlorite solution before trimming in controlling microbial load - a randomized controlled trial

Materials and Methods:

Completely and partially edentulous patients wearing maxillary prosthesis requiring denture adjustments, who satisfy the inclusion and exclusion criteria will be selected for the study. The acrylic denture prostheses will be randomly assigned to two groups - Group 1 and Group 2. Group 1 will be subjected to Conventional disinfection protocol and Group 2 to modified disinfection protocol. Care is taken to keep the number of each type of prostheses ( RPD and CD) equal in both the groups for comparability.

Conventional Disinfection Protocol

The dental personnel after donning appropriate personal protective gears, including gloves, masks, goggles, apron and face shield, will remove the acrylic prosthesis from the patients mouth and swab the palatal intaglio surface to estimate the contamination level of the prosthesis. Patient is then instructed to clean the denture with a soft toothbrush. Following which the prostheses will be disinfected by immersion in 0.5% sodium hypochlorite solution for 20 min. Patients will be instructed to rinse the mouth for 30 seconds with 10ml of 1% povidone iodine mouthwash followed by insertion of the prosthesis in the mouth for 1 min to address patient complaint.  The dental personnel will perform the trimming on dental lathe using tungsten carbide cross cut acrylic trimmer for 1 min at 6500rpm followed by washing in sterile distilled water  for 30 sec to remove acrylic debris. This cycle of insertion and trimming  will be repeated twice more. At the end of third cycle  swab will be collected again.

Modified Disinfection Protocol

Preparation of the patient and the prosthesis is done as in the Conventional disinfection protocol.  Unlike the conventional protocol, the acrylic denture prosthesis will be immersed in 1.0 % sodium hypochlorite solution for one minute and thereafter washed in sterile distilled water  for 30 seconds before it is trimmed. This cycle of insertion, disinfection, washing and trimming is repeated twice more. At the end of third cycle  swab will be collected again.

Collection of Samples for Microbiology

Samples will be  collected with sterile cotton-tipped swabs from the acrylic prosthesis along a 1.5inch x 1.5inch flat  surface of the intaglio in a rolling fashion for 60 seconds and then plated onto the culture media. The co-investigator will use a stop watch for monitoring the time.

Microbiological Analysis

Microbiological analysis will be performed to isolate and identify common oral gram positive and gram negstive  bacteria and Candida species. Swabs will cultured onto blood agar (BA) for microbial count and MacConkey agar for aerobic Gram-negative bacteria (AGNB).