Effect Of Surface Removal Following Bleaching On The Bond Strength Of Enamel & Prosthodontic Case Report

Purpose.This study aimed to evaluate the effect of surface removal following bleaching on the micro-shear bond strength(?SBS)of bleached enamelMaterials and methods.Forty-eight specimens were prepared from bovine incisors and were randomly divided into 2 groups(n = 24): group B(bleaching with 40% hydrogen peroxide for 2 x 45 min with a 1-week interval)and group C(control group without bleaching treatment).Immediately after receiving the treatments,0.5 mm of the enamel was removed from the specimen surface,followed by bonding of the enamel surface with composite resin.Each group was further divided into 2 subgroups of 12 specimens each: subgroup T(with 5,000 thermocycles in water baths at 5°C and 55°C),and subgroup N(without thermocycling).The ?SBS values were measured using a universal testing machine and subjected to two-way analysis of variance(? = 0.05).The fracture modes of the specimens were observed using a stereomicroscope.Results.The ?SBS values of the different groups ranged from 21.42 to 25.21 MPa.Bleaching treatment and thermocycling did not significantly affect the ?SBS values(P = 0.348 and P = 0.507,respectively).No significant interaction was found between the bleaching treatment and thermocycling(P = 0.514).All the groups exhibited a high percentage of mixed failures.Conclusion.The results suggested that the bonding procedure could be performed on the bleached enamel following a surface reduction of 0.5 mm immediately after the bleaching treatment.Part Two.Prosthodontic Case ReportPurpose.This article shows several case reports of aesthetic restoration of anterior teeth,occlusal veneer and crown restoration of posterior teeth,and the restoration of edentulous teeth.The different types of restoration mentioned above have been performed successfully.The repair method and repair effect were discussed as below.Materials and methods.Six cases of prosthodontics were collected from patients who visited the Department of Prosthodontics of Fujian Medical University Affiliated Stomatological Hospital from December 2017 to March 2019.According to the patients' oral health conditions and different personal needs,the restoration methods of occlusal veneer,single crown,fixed partial denture(FPD),implant restoration and complete denture were adopted,respectively.Digital Smile Design,gingival molding technology,Computer-aided design and computer-aided manufacturing(CAD/CAM)technology and duplicate the complete denture were applied.Zirconia ceramics or glass ceramics were selected as repair materials.All tooth restoration procedures were operated in strict accordance with the product manual.Results.There are in total five cases reported here which are about the aesthetic restoration of anterior teeth,implant and full crown restoration of posterior teeth and restoration of edentulous teeth.Due to patients' individual situation and personal demands,different repair schemes were adopted.In relation to the aesthetic restoration of anterior teeth defects,digital smile design was applied.Meanwhile,zirconia was selected for single crown restoration.The postoperative restoration effect was consistent with the preoperative design.With respect to the fixed bridge restoration tooth preparation for dentition defect,the oval shape of the gingival end of the bridge was selected so that the coordinated gingival contour could be obtained.With regards to the oral implant restoration of dentition defect,the temporary prosthesis was adopted.It has shaped gingiva as well as soft tissue gradually,enhancing the aesthetic effects dramatically.As to the restorations of posterior teeth with defects,the technology of computer-aided design and computer-aided manufacturing(CAD/CAM)was applied.Such technology ensures that the restoration can be completed on the same day.As CAD/CAM is fast and comfortable,the number of patients' return visits has been reduced and a high degree of patient preference has been achieved.Conclusion.As concerns edentulous jaw restoration,new denture that meets the design requirements retains the form of old denture and simplifies the treatment process.As a result,it takes less time for patients to get used to the new denture.All the patients were very satisfied with the repair effect.The simple technique for making duplicate dentures makes it easy and convenient for patients to obtain a satisfactory new denture.