Application prospect of polyetheretherketone in postcore crown restorations / 口腔疾病防治

@#Polyetheretherketone (PEEK) is known as a high-grade engineering plastic with good mechanical properties, chemical stability and biocompatibility. Currently, PEEK materials have been widely used in prosthodontics, such as complete dentures and removable partial dentures. The relevant research shows that PEEK posts are superior to glass fiber posts, which have high tensile bond strength and bending strength. At present, few case reports of PEEK postcores have been published, and clinical case reports suggest that PEEK postcores have good oral prosthetic aesthetics and are ideal and reliable postcore crown materials. However, the preparation and surface treatment methods of PEEK require further refinement. A review of the related properties of PEEK and the prospects of its application in the field of postcore crown restoration will be presented in this paper.

Finite element stress analysis of weakened root of maxillary central incisors restored with titanium post-core and fiber post-core systems / 西安交通大学学报(医学版)

Objective To analyze the stress distribution of the weakened root dentine restored with titanium post-core crown and fiber post-core crown by finite element method.Methods The sample was scanned by Inveon Micro-CT technology from incised margin to root apex at 21 μm interval to obtain transverse data of DICOM format.The three-dimensional finite element model was created by rebuilding the morphology of maxillary central incisor with Inveon Research Workplace as well as Mimics,Geomagic and Catia software.The model was meshed and loaded to analyze the stress distribution on the weakened dentine of root by finite element method.Results The maximum stress,shearing stress and equivalent stress of the root restored with fiber post-core crown were 60%less than the stresses of the root restored with titanium post-core crown in the experiment.The stress on various parts of the root restored with titanium post-core crown was higher than that of the root restored with fiber post-core crown.Furthermore,the stress concentration occurred mainly on the labial interface of the upper 1/3 of root. Especially when the root was restored with titanium post-core crown,the stress value reached 37 .73 MPa,which was 1.9 times that of fiber post-core crown.Conclusion The finite element analysis indicates that the fiber post-core crown is better than titanium post-core crown in avoiding stress concentration and root fracture in the restoration of weakened root of maxillary central incisors.

Evaluation on clinical effect of cast pure titanium split post crown restoration of molars with low occlusogingival distance and large root furcation / 吉林大学学报(医学版)

Objective:To observe the clinical effects of split post crown and split post-core crown in restoring the molars with low occlusogingival distance and large root furcation,and to clarify its advantages and analyze its improvement methods.Methods:Forty-nine molars of twenty-nine patients,which had been completely treated with root canal therapy,were restored by split post crown or split post-core crown according to their wills.Split post crown was used in twenty-three cases,and split post core crown was applied in the other twenty-six cases.The clinical effects of the patients in two groups were observed after 12 and 24 months follow-up.The levels of MMP-8 in gingival crevicular fluid were checked and compared 12 months after restoration.Results:The restoration success rates of split post crown were 95.7％ after 12-month treatment and 82.6 ％ after 24-month treatment,respectively;there was no significant difference between them (P＞ 0.05).The success rates of split post-core crown were 84.6％ after 12-month treatment and 52.2％ after 24-month treatment,respectively;there was significant difference between them (P＜0.05).The success rate of split post crown was significantly higher than that of split post-core crown after 24-month treatment (P＜0.05).The levels of MMP-8 in gingival crevicular fluid of the patients were close to each other,there was no statistical significance (P＞0.05).Conclusion;The split post crown shows better clinical effect in restoring the molars with low occlusogingival distance in 24 months than split postcore crown.Targeted improvement will help to improve the clinical success rate.

Evaluation on clinical effect of cast pure titanium split post crown restoration of molars with low occlusogingival distance and large root furcation / 吉林大学学报(医学版)

Objective:To observe the clinical effects of split post crown and split post-core crown in restoring the molars with low occlusogingival distance and large root furcation,and to clarify its advantages and analyze its improvement methods.Methods:Forty-nine molars of twenty-nine patients,which had been completely treated with root canal therapy,were restored by split post crown or split post-core crown according to their wills.Split post crown was used in twenty-three cases,and split post core crown was applied in the other twenty-six cases.The clinical effects of the patients in two groups were observed after 12 and 24 months follow-up.The levels of MMP-8 in gingival crevicular fluid were checked and compared 12 months after restoration.Results:The restoration success rates of split post crown were 95.7％ after 12-month treatment and 82.6 ％ after 24-month treatment,respectively;there was no significant difference between them (P＞ 0.05).The success rates of split post-core crown were 84.6％ after 12-month treatment and 52.2％ after 24-month treatment,respectively;there was significant difference between them (P＜0.05).The success rate of split post crown was significantly higher than that of split post-core crown after 24-month treatment (P＜0.05).The levels of MMP-8 in gingival crevicular fluid of the patients were close to each other,there was no statistical significance (P＞0.05).Conclusion;The split post crown shows better clinical effect in restoring the molars with low occlusogingival distance in 24 months than split postcore crown.Targeted improvement will help to improve the clinical success rate.

Comparison of influence of resin core on overall bending strength of fiber post-core restoration / 中国基层医药

Objective To compare the influence of resin core on overall bending strength of fiber post-core restoration.Methods 60 mandibular first premolar extracted because of orthodontic treatment was selected.3M light -cured composite resin P60,medental dual-cured resin,pulpdent dual-cured resin combined with viva carbon fiber reinforced glass fiber post were applied.The changes of teeth in vitro were observed when strength was given on.Results The flexural strength of 3M light-cured composite resin was (80.182 ±9.512)N,Medental dual-cured resin was (87.805 ± 11.649) N,Pulpdent dual-cured resin was (85.458 ± 10.845) N.The flexural strength of 3 M light-cured composite resin was lower than that of medental dual-cured resin and pulpdent dual-cured resin (t =5.758,3.084,both P ＜ 0.05).There was no statistical differences of flexural strength between medental dual-cured resin and pulpdent dual-cured resin(t =0.718,P ＞ 0.05).There was large area of resin broken off after 3M light-cured composite resin core fracture.There was only fracture of medental dual-cured resin core and pulpdent dual-cured resin core.Conclusion The bending strength of dual-cured resin is better than that of highly filled light curing composite resin in large tooth hard tissue defect restoration with fiber post-core,and core broken off is rare.Dual-cured resin is better post-core materials.

Three dimensional finite element stress analysis of the post-core crown restored posterior stump of teeth with different adhesives / 重庆医科大学学报

Objective:To compare the effects on the size and distribution of stress of different adhesives on post-core crown restored posterior stump of teeth dentin, to discover reasonable post-crown adhesive material of posterior stump of teeth post-core crown,by three dimensional finite element analyses. Methods:Establish three dimensional finite element models of maxillary first molar post-core crown by CT scanning, Mimics and Abaqus software,which include post core,crown,tooth root, pericementum,alveolar bone and adhesive material. Divide above models into experimental and control group according to the relative adhesive material. Choose three load spots on the occlusal surface of this model, and exert 80N loading strength on each. Then calculate the peak value and distribution mode of Von mises stress,max-principle stress and shear stress. Results:In the different adhesive material experimental groups,the peak value of the stress on the dentin of the composite resin group was lower than those in zinc phosphate groups. Conclusion:On the condition of this experiment,different adhesives have different effects on the peak value and distribution of the stress on the post-core crown restored posterior stump of teeth dentin.

The three-dimension finite element analysis on stress of different length post of posterior tooth on post-core crown / 重庆医科大学学报

Objective: To compare influence of residual dentin stress on condition of different post length of posterior teeth post-core,to discover reasonable post length of posterior teeth post-core,in order to instruct clinic rational design.Methods:Models were created by abrasive method and way which pictures were acqiured with digital camera.To generate three-dimensional models of maxillary firster molar which is short in medial palatal cusp restored with post-core crown.Then analyse magnitude and distribution of model residual dentin stress by the three-dimension finite element analysis.Result:When maxillary firster molar which is short in medial palatal cusp restored with middle fusion metal post-core and porcelain fused mental crown,on condition of 1/2 post length and2/3 post lengths,it has the same magnitude of Von mises stress? most main stress ? least main stress and the same stress distribution on residual dentin.Conclusion:When maxillary firster molar which is short in medial palatal cusp restored with middle fusion metal post-core and porcelain fused mental crown,on condition of 1/2 post length and2/3 post lengths,it has no infulence in magnitude and distribution of stress of residual dentin.