One-year Clinical Effect Observation Of IRoot BP Plus Repairing The Molar With Perforation Of Pulp Chamber Floor

Background:The molar with perforation of pulp chamber floor can be defined as an abnormal passage between root canal system and periodontal tissues^[1],etiology can be divided into the iatrogenic（improper access cavity preparation,post preparation,root canal preparation,etc.）and pathological（caries,internal and external resorption）,the channel will be the pulp cavity connected with periodontal support tissues,it will influence the prognosis of the tooth,and it was the second most common cause of root canal treatment failure after root filling^[2].Perforation during root canal treatment is a major factor in failure of up to 9.6%of root canal treatment^[3].Perforation of pulp chamber floor causes the gingival epithelium to grow down into the perforated area,leading to the inflammatory response and loss of attachment associated with periodontal tissue and alveolar bone destruction,which impinges on the health of the periapical tissue and ultimately affects the prognosis of the tooth.If left untreated,the perforation will lead to loss of root integrity and further damage to adjacent periodontal tissues^[4],which will eventually lead to loosening and extraction of the affected tooth and affect the stability of bite^[5].Successful treatment depends on accurate diagnosis and visualization of perforations and the use of biocompatible materials that are effective in sealing perforations and preventing bacterial penetration^[4].The ideal repair materials should have the following properties:（1）adequate sealing ability;（2）good biocompatibility;（3）good antibacterial and bacteriostatic properties;（4）no carcinogenicity;（5）insolubility and X-ray resistance;（6）convenient operation;（7）no irritation and toxicity to periodontal tissues;（8）induce bone tissue or cementum formation;（9）promote the repair and regeneration ability of periodontal tissue^[6-7].iRoot BP Plus not only has good X-ray resistance,sealing ability,adhesive ability curing performance and compressive strength,but also has no or low toxicity to pulp and periodontal tissue^[8],and can promote biomineralization and the restoration and regeneration of pulp and periodontal tissue^[9-10].As a bioceramics material with good application prospects,it has been widely used in pulp treatment in recent years.There have also been in animal experiments,vitro experimental studies and clinical cases reported abroad about its superior efficacy,but there are not many related reports in China.In this study,iRoot BP Plus was used to repair the perforation of pulp chamber floor,and its clinical effect was observed and studiedObjective:The aim is to observe the clinical effect of iRoot BP Plus in repairing the iatrogenic and caries induced perforation of pulp chamber floor after one year and analyze the factors influencing perforation effect.Methods:72 patients’molars with perforation of pulp chamber floor were collected,isolated by rubber barrier,and the coronal sealing material was removed by high-speed drilling.The perforation site was found under the microscope,and the perforation site was rinsed and stopped bleeding with 3%sodium hypochlorite solution.The perforation size was measured and recorded.After routine root canal preparation,root canal was irrigated with 3%sodium hypochlorite solution and physiological saline,then the ultrasonic washing was used,then the root canal was dried and blocked with the paper point.Finally iRoot BP Plus was covered on the perforation,pressured it force gently,sterile damp cotton ball covered on the material,calcium hydroxide paste was sealed into the root canals,then Caviton was used to fill the cavity temporarily.The patient returned to the hospital after one week.The molar was isolated by rubber barrier and the Caviton and wet cotton ball was removed,then the hardness of iRoot BP Plus was investigated.The canal was rinsed and disinfected with 3%sodium hypochlorite solution and normal saline.Then,17%EDTA was used for irrigating to reduce the debris in the defect area,and normal saline was used for final irrigating,paper tip was sucked dry,AH-Plus paste and continuous wave hot gum was used with vertical compression to seal the root canal,then the cavity was cleaned,the root canal orifice and the pulp cavity were sealed with bulk flow resin,and the crown was filled with 3M Z350 composite resin.Postoperative apical films and intraoral photos were taken and the patients were recalled one year after surgery to evaluate the postoperative clinical effect and the factors affecting the effect of perforationResult:（1）Compared with caries induced perforation,the treatment effect of perforation was significantly worse than iatrogenic perforation（P<0.05）.（2）Compared with short time perforation,the treatment effect of perforation was worse in patients with infection for more than half a year（P<0.05）.（3）The success rate of perforation diameter>3mm was 62.50%,the success rate of diameter 2-3mm was 92.31%,and the success rate of diameter<2mm was 95.45%,the success rate of diameter>3mm was significantly lower than that of the other two groups,P<0.05.Conclusion:Factors such as the cause,infection time and size of perforation should be considered when repairing the perforation of pulp chamber floor with iRoot BP Plus,so as to preserve the affected tooth to a greater extent.