title: [Application of bolt-like post crown system in restoration of molar residual root and crown with low occlusogingival distance].
abstract: OBJECTIVE
  To evaluate the clinical effects of bolt-like post crown system in restoration of molar residual root and crown with low occlusogingival distance and large root bifurcation angle.
  
  
  METHODS
  Thirty two molar residual roots and crowns from 25 patients with low occlusogingival distance (<4 mm) and large root bifurcation angle were involved in this study. First, the root canals were prepared according to their natural directions following the standard procedures. Accurate impressions were taken with silicone. The core crown and the post which would inserted the straight root canal were founded together,and the blot-like post which would inserted the root canal with bigger bifurcat were founded alone. Finally, the two parts were cemented together in patient after try-in with RelyX™ Unicem cement.
  
  
  RESULTS
  Except 3 patients who were lost during the follow up period, the remaining 22 patients (29 restorations) were followed up for 1 to 5 years. No prosthetic loosening or root fracture was observed during the follow-up period. All the fixed restorations were found with good marginal fitness, well masticatory function and favorable proximal contact relationship.
  
  
  CONCLUSIONS
  Bolt-like post crown system is an ideal method for restoration of molar residual root and crown with low occlusogingival distance and large root bifurcation angle. This approach has positive effect on the retention, function and aesthetic outcome of the fixed restorations of molar residual root and crown with low occlusogingival distance.
authors.affiliation: Department of Stomatology, Zhejiang Provincial People's Hospital, Hangzhou 310014, Zhejiang Province, China.
authors.forename: Jian-xing
authors.initials: JX
authors.lastname: Zhang
authors.forename: Zhi-qiang
authors.initials: ZQ
authors.lastname: Cao
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Si-ping
authors.initials: SP
authors.lastname: Lv
mesh_terms: D003442:Crowns; D005899:Glass Ionomer Cements; D006801:Humans; D008963:Molar; D011176:Post and Core Technique; D012390:Root Canal Therapy; D019228:Tooth Crown
chemical_list: D005899:Glass Ionomer Cements