| Purpose: We are aiming to study the morphological changes of molar and premolar teeth with due to root canal treatment as well as its effect on periodontal tissues.Methods:Thirty cases of with healthy periodontal tissues and thirty cases of chronic periodontitis were selected,all of them required root canal treatment.Sixty teeth from 58 patients were observed and divided into 4 groups with 15 cases in each group: group A(healthy periodontal tissues and inlay restoration);group B(healthy periodontal tissues and crown restoration);group C(periodontitis and inlay restoration);and group D(periodontitis and crown restoration).Before the treatment,plaster models for the teeth were made using silicone rubber,various clinical periodontal indices were recorded,includes probing depth,gingival index,plaque index,sulcus bleeding index and gingival crevicular fluids were collected.After root canal treatment,the teeth restored in accordance with the principle of inlay preparation or the principle of crown preparation.Furthermore,after the patients were seated the restorations,the plaster models of the teeth were made using silicone rubber.Gingival crevicular fluids were collected again at the next visit one year later and various clinical periodontal indices were recorded simultaneously.We also used an extra oral scanner from Sirona Dental Systems Gmb H to scan the plaster models and we employed Geomagic Qualify 12.0 to perform the best fitting alignment and 3D comparison of the data before and after the restoration.Each pair of models is divided into 6 observational surfaces,includes 1/2 of the functional tip of the occlusal surface,1/2 of the nonfunctional tip of the occlusal surface;the proximal-occlusal surface? and the proximal-gingival end ? in the buccal sides;the proximal-occlusal surface? and the proximal-gingival end ? in the lingual sides.Moreover,the averaged errors(AE)and color maps for difference distribution between the paired data were output respectively.Record all inspection data,and statistical analysis was performed using SPSS17.0 software by category.Result:1.The morphological changes of the teeth with crown restoration in the proximal-occlusal surface?,the proximal-gingival end ? in the buccal sides well as the proximal-gingival end 1/2 in the lingual side are greater than that of inlay restoration,and what's more,there are statistically significant differences between the two quantitates(p<0.05).2.The patients in group C and group D who received initial periodontal treatment,the levels of prostaglandin E2(PGE2)and elastase(EA)in the gingival crevicular fluids,as well as the probing depth,the gingival index,the plaque index,and the sulcus bleeding index are all significantly reduced and they are statistically significant after one year's restoration(p<0.05).On the other hand,in terms of the patients with healthy periodontal tissues,there is no obvious change in the indexes mentioned above(p>0.05).Conclusion: 1.The quantities in morphological changes for the original shape of the teeth in the buccal-lingual side due to crown restoration are greater than that of inlay restoration.This indicates that the whole crown restoration has lost the shape of the original tooth in the process of preparing teeth.2.During the process of denture manufacture,the technicians could not restore the original shape of the tooth because of no reference,making the shape of the crown restored with the original tooth,but there is no significant effect on the periodontal tissues.Inlay repair mostly retained one side of tooth and prepared less for buccal and lingual tooth tissue during tooth preparation.Inlay making also restored the shape of tooth under the guidance of original tooth shape,and had little change on the original anatomy of tooth.Inlay repair should be given priority to the teeth after root canal therapy.3.The periodontal statuses of the diseased teeth with chronic periodontal diseases are significantly improved after receiving the initial periodontal treatment. |
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