title: Evaluation of occlusal fracture resistance of three different core materials using the Nayyar core technique.
abstract: OBJECTIVE
  The aim and purpose of this study was to determine the occlusal fracture resistance of three core buildup materials using the Nayyar technique.
  
  
  METHODS
  Thirty human extracted maxillary premolars were used for the study. The test samples were decoronated till the cementoenamel junction (CEJ) and proper cleaning and shaping was done with protaper niti files till the F3. Corresponding f3 protaper(Dentysply)gutta pecha cones were selected and obturated. The gutta-percha was removed till the depth of 4 mm from the coronal orifice with Gates Glidden (GG) drills for all the samples; then the samples were randomly divided into three different groups. Group I was restored with universal composite Z350XT, group II was restored with light curable glass ionomer cement (GIC), and group III was restored with miracle mix. The coronal buildup was done using compound supported matrix. The fracture resistance strength of all the specimen groups was tested under a universal testing machine.
  
  
  RESULTS
  The data of the study were statistically analyzed by one-way analysis of variance (ANOVA) and Bonferroni's comparison test. Results of the study showed that group I that was restored with the universal composite Z350XT showed much higher fracture resistance strength compared to the other two groups. Statistically significant difference was noted between group I and group II and also between group I and group III.
  
  
  CONCLUSIONS
  It can be concluded that the core buildup done with composite offered better occlusal fracture resistance strength compared to light curable GIC and miracle mix.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Lenora Dental College and Hospital, Rajahmundary, Andra Pradesh, India.
authors.forename: Satti Narayana
authors.initials: SN
authors.lastname: Reddy
authors.affiliation: Department of Prosthodontics, Dr. Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinaoutpally, India.
authors.forename: Kolli
authors.initials: K
authors.lastname: Harika
authors.affiliation: Department of Pedodontics, SVS Institute of Dental Sciences, Mahabubnagar, Telangana, India.
authors.forename: Shobha
authors.initials: S
authors.lastname: Manjula
authors.affiliation: Department of Pedodontics, Lenora Dental College and Hospital, Rajahmundary, Andra Pradesh, India.
authors.forename: Pavani
authors.initials: P
authors.lastname: Chandra
authors.affiliation: Department of Communitynand Preventive Dentistry, CKS Teja Institute of Dental Sciences, Tirupati, Kerala, India.
authors.forename: Lokesh
authors.initials: L
authors.lastname: Vengi
authors.affiliation: Department of Conservative Dentistry and Endodontics, Sree Sai Dental College and Research Institute, Srikakulam, Andhra Pradesh, India.
authors.forename: Krishna Mohan
authors.initials: KM
authors.lastname: Koka
keywords: Core buildup materials; Nayyar cores; corono-radicular build-up; fracture; fracture resistance; materials; resistance