| At present, the caries rate and untreated rate of children in primary dentition in China are in a high level. Large area caries of deciduous teeth not only affect oral function, thus affecting the normal growth and development of children, but also affect the appearance, adversely influencing physical and mental development of childrenIn the daily clinical work, the most commonly used restoration methods are composite resin and glass ionomer filling. But filling resin is easy to shrink after curing, glass ionomer filling is stringent requirements on the wet environment. All of these are easy to produce secondary caries, thus affecting the final restoring effect. With the development of material science, preformed crown is gradually applied to the primary dentition. Although its application has been reported, the advantages and disadvantages of details are not fully understood.This study through clinical therapeutic effect and in vitro experiments to evaluate all-round aspect of the composite resin filling, preveneered and stainless steel crown, preformed metal crown and zirconia crown, providing reference for clinical selecting appropriate restoring methods.1. Evaluation of clinical prognosis of composite resin filling and preformed crown restoration for severe early childhood caries.2. Survey of cognition and acceptance of pediatric dentists and parents on restoration methods in primary teeth3. The compressive strength and fatigue strength tests of composite resin filling and preformed crown restoration of primary teeth4. Experimental study on microleakage of composite resin filling and preformed crown restoration of primary teethMethod:1. A retrospective study was carried out in the Department of Pediatric Dentistry from 2011 to 2014. Severe early childhood caries patients were all at 3-6 years old. We transfer the file cases in general anesthesia, telephone reservation and notify the child and the guardian of the return visit time. The children are unified by 2 pediatric dentists in the Department of Stomatology.2. Stomatological hospitals of Shaanxi Province, Shandong Province and Heilongjiang Province were chosen and questionnaires were given to pediatric dentists in conference breaks. All the questionnaires were collected at the end of conferences. The questionnaire was conducted on selection of restoration methods of primary teeth caries after routine treatment, mainly involving composite resin filling, strip crown of primary anteriors, preformed metal crown of primary molars and zirconia crown. At the same time, releasing questionnaire randomly to the parents whose children were returning in the first part from 2014 to 2015. On the basis of their understanding of the advantages and disadvantages of different repair methods, all the patients investigated were told to choose the best restoration method.3. This study collected extracted primary molars and incisors due to apical periodontitis and retained deciduous teeth. All the collected teeth had root absorption not more than 2/3.The teeth were divided into the incisor group and molar group. All the samples were randomly divided into control group and experimental group. The experimental incisor groups were divided into composite resin group, preveneered and stainless steel crown The main contents are as follows: group and zirconia crown group, also the experimental molar groups were divided into composite resin group, preformed metal crown group and zirconia crown group. Experiment respectively in each group has 10 teeth, the control group were 5 teeth.4. This study collected extracted primary molars and incisors like previous study. The teeth were divided into the incisor group and molar group. All the samples were randomly divided into control group and experimental group. The experimental incisor groups were divided into composite resin filling self-etching bonding group, preveneered and stainless steel crown bounding with glass ionomer cement group, zirconia crown bounding with BioCem group and zirconia crown bounding with glass ionomer cement group, also the experimental molar groups were divided into composite resin filling self-etching bonding group, preformed metal crown bounding with glass ionomer cement group, zirconia crown bounding with BioCem group and zirconia crown bounding with glass ionomer cement group. Experiment respectively in each group has 5teeth.Results:1. Under general anesthesia, 3669 teeth of 318 patients in total were treated. In short term both for indirect pulp therapy and root canal therapy(RCT), the success rate of direct composite resin filling and crown restoration had no statistical significance. However, in a long term observation, the success rate of crown restoration was significantly higher than that of resin filling. The main failure reason for crown restoration was that they were not suitably selected while the main failure reason for composite resin filling was secondary caries.2. Results of pediatric dentists' survey showed that they preferred preformed crowns more than composite resin filling with statistical significance. Zirconia crown slightly better than strip crown and preformed metal crown, the difference was not statistically significant. Pediatric dentists who choose zirconia crown are large than those who choose strip crown and preformed metal crown exclusion technique sensitive and simple comparing the therapeutic effect. The results of parents' questionnaire show that: the best choice to restore primary teeth after routine treatment is zirconia crown, followed by strip crown and preformed metal crown. The main factor influencing the restoration of anteriors is aesthetic, followed by gingival stimulation and shedding rate. The main factors influencing the restoration of molars are gingival stimulation and secondary caries, followed by the recovery of masticatory function and aesthetic.3. Compared with the control group, the compressive strength and fatigue strength of the composite resin group were significantly decreased, and the difference was with statistical significance. The fatigue strength and compressive strength of preveneered and stainless steel crown group, preformed metal crown group and zirconia crown group were increased, and the fatigue strength of zirconia crown group was better than that of preformed metal crown.4. Compared with composite resin filling self-etching bonding, preformed crown had a less microleakage with statistical significance. The microleakage of zirconia crown bounding with BioCem is significantly less than that of zirconia crown bounding with glass ionomer cement, and the difference is statistically significant. The microleakage of zirconia crown bounding with glass ionomer cement is slightly less than that of preformed metal crown bounding with glass ionomer cement, but the difference was not statistically significant.Conclusion:1. For large area caries of primary teeth, the restoration of preformed crown is better than composite resin filling in clinical.2. At present, pediatric dentists believe that the restoration of zirconia crown is a new aesthetic restoration method which is significantly better than that of preformed metal crown, strip crown and composite resin filling in clinical curative effect, also should deserve to apply in the clinic. The parents of the children also believe that the restoration of zirconia crown is beautiful and comfortable which is a kind of popular restoration of primary teeth.3. The fatigue strength and compressive strength of zirconia crown was better than that of preveneered and stainless steel crown and composite resin, which can protect the remaining teeth after preparation, was worth applying in the clinic.4. The microleakage of zirconia crown bounding with BioCem is the least, the second is zirconia crown bounding with glass ionomer cement and preformed metal crown bounding with glass ionomer cement, the microleakage of composite resin filling self-etching bonding is the highest. |
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