Long-term calcium hydroxide as a root canal dressing may increase risk of root fracture.
It has been proposed (Cvek 1992) that immature teeth are weakened by filling of the root canals with calcium hydroxide dressing and gutta-percha. The aim of the present study was to test the hypothesis that dentin in contact with calcium hydroxide would show a reduction in fracture strength after a certain period of time. Immature mandibular incisors from sheep were extracted and divided into two experimental groups. Group 1: the pulps were extirpated via the apical foramen. The root canals were then filled with calcium hydroxide (Calasept) and sealed with IRM(R) cement, and the teeth were then stored in saline at room temperature for 0.5, 1, 2, 3, 6, 9, or 12 months. Group 2: the pulps were extirpated and the root canals were filled with saline and sealed with IRM(R) cement. The teeth were then stored in saline for 2 months. Intact teeth served as controls and were tested immediately after extraction. All teeth were tested for fracture strength in an Instron testing machine at the indicated observation periods. The results showed a markedly decrease in fracture strength with increasing storage time for group 1 (calcium hydroxide dressing). The results indicate that the fracture strength of calcium hydroxide-filled immature teeth will be halved in about a year due to the root filling. The finding may explain the frequent reported fractures of immature teeth filled with calcium hydroxide for extended periods.
Department of Oral and Maxillofacial Surgery, University Hospital, Rigshospitalet, Copenhagen, Denmark.
Jens Ove
JO
Andreasen
Ban
B
Farik
Erik Christian
EC
Munksgaard
D000704:Analysis of Variance; D000818:Animals; D002126:Calcium Hydroxide / Q000009:adverse effects*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000187:drug effects; D007180:Incisor; D008768:Methylmethacrylates / Q000627:therapeutic use; D011670:Pulpectomy; D012307:Risk Factors; D012387:Root Canal Filling Materials / Q000009:adverse effects* / Q000627:therapeutic use; D012756:Sheep; D012965:Sodium Chloride; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013997:Time Factors; D014082:Tooth Fractures / Q000209:etiology* / Q000503:physiopathology; D014092:Tooth Root / Q000187:drug effects*; D015035:Zinc Oxide-Eugenol Cement / Q000627:therapeutic use
D008768:Methylmethacrylates; D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; D012965:Sodium Chloride; C031667:IRM cement; D002126:Calcium Hydroxide