Reattachment of anterior fractured teeth: effect of materials and techniques on impact strength.
OBJECTIVE
The reattachment of dental fragments, as a conservative treatment, should be the first choice to restore fractured teeth. Therefore, the aim of this study was to evaluate the effect of different materials and reattachment techniques on impact strength of bovine incisors.


METHODS
Standardized fragments were obtained when 80 crowns were sectioned 12 mm from the incisal edge. Teeth were mounted in PVC rings, embedded in acrylic resin and polyether to simulate bone support and periodontal ligament. Specimens were distributed in nine groups (n = 10), according to the reattachment technique (Direct bonding or Circumferential chamfer); the adhesive system (Single Bond or Clearfil SE Bond); and the intermediated material (Filtek Z350 Flow or Rely X CRA). Sound teeth composed the control group. Circumferential chamfer was prepared after the bonding of the fragment by means of a spherical point and filled with the composite Filtek Z250. The impact strength was evaluated in a universal testing machine Instron. A compressive load was applied at a crosshead speed of 500 mm min(-1) on the buccal surface, 2 mm from the incisal edge. Data were submitted to anova and Ryan-Einot-Gabriel-Welsch Multiple Range test (5%).


RESULTS
Mean value of impact strength for control group was 64.8 Kgf. The fragment reattachment using Circumferential chamfer was significantly superior to Direct Bonding. The use of Single Bond significantly increased the impact strength when compared to the use of Clearfil SE. There was no significant difference among Rely X and Filtek X350 Flow.


CONCLUSIONS
No technique or material, when individually considered, was capable of achieving the mechanical strength of the sound teeth; however, the association of reattachment technique Circumferential chamfer with bonding system Single Bond could approximate the immediate impact strength of the restored teeth to that observed in the sound teeth.
Bruschi-Alonso
Renata Camila
RC
Department of Restorative Dentistry, Piracicaba Dental School - UNICAMP, Piracicaba-SP, São Paulo, Brazil.
Alonso
Roberta Caroline Bruschi
RC
Correr
Gisele Maria
GM
Alves
Marcelo Corrêa
MC
Lewgoy
Hugo Roberto
HR
Sinhoreti
Mário Alexandre Coelho
MA
Puppin-Rontani
Regina Maria
RM
Correr-Sobrinho
Lourenço
L
D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D001696:Biomechanical Phenomena; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006813:Humidity; D008422:Materials Testing; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D019228:Tooth Crown / Q000293:injuries / Q000503:physiopathology; D014082:Tooth Fractures / Q000503:physiopathology / Q000628:therapy*; D019246:Tooth Preparation / Q000379:methods
C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C467913:Filtek Flow; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; C533204:filtek Z350; C115612:single bond; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate