The Effect Of Oral Irrigator On The Microorganism Constitution Adhered On The Gingival Side Of PFM Pontic

Objectives:Brushing can remove all dental plaque. So people need to use toothpicks, dental floss and oral irrigator also. Oral irrigator is commonly known as "water floss", and is used to prevent periodontitis and keep the oral hygiene of orthodontic patients. The study of oral irrigator used on the fixed bridge and dental implants were rare. The primary task is to develop a dental plaque collector on the gingival side of PFM fixed bridge pontic which could avoid the traditional defect in plaque collection. Then, the microorganism constitution on the collector were analyzed by SEM and Illumina high-throughput sequencing technology with or without the treatment of oral irrigator.Methods:In this study,6 healthy adult volunteers were chosen for their third molar was extracted more than 3 months and alveolar crests were smooth. They were randomly divided volunteers into experimental groups and control groups were tough the uniform brushing methods. All the volunteers lived in Kunming during the experiment After the oral cast were made, the dental plaque collecting device with detachable ceramic collector were fabricated and fitted in mouth. The dental plaque were removed from the collector by the ultrasonic from a sonicator, under conditions of 30W/30S,30W/1min,30W/1.5min and 50W/1min, then the samples were observed with SEM. When the dental plaque collector detached from the pontics, the specimens were observed by SEM, then the dental plaque on the collector were removed from the surface by sonicator under the condition optimized before, and the dental plaque suspension were analyzed by high throughput sequencing to reveal the microorganism constitution.Results:(1) Dental plaque was observed formed on the substitution of PFM fixed bridge and the substitution could imitate the mobility of fixed bridge in the patient’s mouth and touch forms with the alveolar crest and so on.(2) After the preliminary experiment, the suitable mode of the sonicator to elute plaque on the surface of gingival side of pontic of PFM fixed bridge was 30W/1 min.(3) Obvious accumulation of food debris were not seen at the experimental group.(4) Within the experiment period, plaque became denser and thicker on the surface of substitution of the control group than experimental group, but the bacterial adhesion is later and looser than experimental group.(5) The analysis of microbial diversity indicated that total species of bacteria on experimental group was less than the control group. The abundance of bacteria species between the experimental and control groups was studied. The common streptococcus, prevotella, fusobacterium et al were not significantly difference (P> 0.05) except Ralstonia (P< 0.05).Conclusions:(1) Dental plaque formed on collector of plaque that made the next step possible.(2) Sonicator successfully eluted plaque on the surface of denture. The DNA successfully extracted from miscible liquids of dental plaque.(3) Oral irrigator inhibited the maturation of plaque on the gingival side of pontic and microbial diversity has been reduced. But the changes had no significant difference.(4) Whether the oral irrigator was used or not, the ingredients of plaque on the gingival side of pontic of PFM fixed bridge was no significant difference in the experimental period.