Factors Influencing The Effect Of Vital Pulp Therapy On Pulpitis Caused By Caries

Objective:At present,textbooks believe that the reversible pulpitis of mature permanent teeth can be treated by vital pulp therapy（VPT）,and the irreversible pulpitis is the contraindication of VPT.However,there are also failure cases after the reversible pulpitis is treated by VPT,and there are also successful cases of irreversible pulpitis.The purpose of this study is to study the influencing factors of the effect of VPT in the treatment of pulpitis caused by deep caries,to predict the effect of VPT,and to assist clinicians to make a reasonable treatment plan before operation.Methods:Cases of pulpitis caused by deep caries of mature permanent teeth were collected from the Department of Endodontics,School of Stomatology,Tianjin Medical University between 2015 and 2019.According to the inclusion criteria and exclusion criteria,117 cases with complete clinical data and one-year follow-up were selected.All cases were examined by consultation,clinical examination and imaging examination,and the clinical diagnosis was made according to the diagnostic criteria of American Association of Endodontics（AAE）.With the informed consents of all patients,the VPT was carried out.During the operation,whether the pulp was exposed,the hemostasis,the type of pulp capping agent（MTA,i Root BP,Biodentine）,and the way of the VPT（direct pulp capping,indirect pulp capping,and pulpotomy）were recorded.Three,six and twelve months after the VPT,the pulp status of the affected teeth was observed.The possible influence factors are X,a total of 13,named X₁,X₂,X₃ to X_13;the effect of vital pulp therapy after 12 months follow-up was determined as Y.First of all,show the missing data and use multiple imputation to supplement the missing data.Single factor Logistic regression was used to analyze the factors that influenced the curative effect of one year after the vital pulp therapy,including the clinical information recorded before and during the operation.Optimal subset regression（OSR）was used to select the best combination of variables and establish the regression model（mod1）.According to clinical experience,the regression model（mod2）was established by using"non stimulating pain（X₆）",cold pulp test（X₇）and hot pulp test（X₈）.Correlation analysis and multiple collinearity analysis were conducted among variables to ensure that there was no collinearity among variables in the regression model.Secondly,receiver operating characteristic curve（ROC）was used to evaluate the discrimination of the model,calibration and goodness of fit were used to evaluate the consistency between the predicted value and the observed value,bootstrap method was used to evaluate the repeatability of the regression model.Finally,regression equation and nomogram were used to show the final selected model,and decision curve was used to analyze whether the model had clinical value.Results:A total of 117 cases were collected,including 4 normal pulps,71 reversible pulpitis and 42 irreversible pulpitis.Single factor Logistic regression analysis showed that the regression coefficientsβof cold pulp test（X₇）and clinical diagnosis(X₁₁)were statistically different（P＜0.05）.The P value of regression coefficientβof the following 11 variables were＞0.05,they were age,sex,type of teeth,whether there was fillings,location of caries,no stimulation pain,hot pulp test,electric pulp test,percussion,type of pulp capping agent and vital pulp therapy.The best combination variables selected by OSR were cold pulp test（X₇）and hot pulp test（X₈）.The multivariate logistic regression analysis showed that the two variables had statistical differences（P＜0.05）.For mod1 and mod2,the area under the ROC curve（AUC）were 0.690 and 0.702,respectively,the U value in the calibration were-0.017,the X² in the goodness of fit test were 1.675 and 6.939,respectively,the root mean squared error（RMSE）of bootstrap method were 0.379 and 0.378,respectively.Besides,there were no statistical difference for the above indexes（P>0.05）.The regression equation established（mod1）was:P=1/（1+e^（-y））,y=-2.281+1.077 X₇-0.884 X₈.The nomogram showed the final regression model（mod1）,and the decision curve analysis showed that the curve of the regression model was overall above the two extreme cases（All,None）.Conclusions:1.Cold pulp test reaction and hot pulp test reaction may be the influencing factors of one-year curative effect of vital pulp therapy of mature permanent teeth,serious cold pulp test reaction may be the risk factors,and serious hot pulp test reaction may be the protective factors.2.Age,sex,type of teeth,presence or absence of fillings,location of caries,"non irritating pain",difference of pulp electrical activity test,percussion,clinical diagnosis,type of pulp capping agent and method of vital pulp therapy did not affect the effect of vital pulp therapy one year later.3.Spontaneous pain and nocturnal pain are not absolute contraindications to vital pulp therapy.4.According to the regression model（mod1）established by cold pulp test and hot pulp test,it has a certain reference value for the prognosis judgment of vital pulp therapy.