title: Freeze-dried bone for maxillary sinus augmentation in sheep. Part II: biomechanical findings.
abstract: This study examines the biomechanical loading capacity of dental implants placed in the posterior maxilla in conjunction with subantral augmentation with either homogeneous demineralized freeze-dried bone from sheep (s-DFDB) or heterogeneous demineralized freeze-dried human bone (h-DFDB) as grafting material in sheep. In 36 adult female mountain sheep, the Schneiderian membrane was elevated extraorally in both maxillary sinuses, and two titanium plasma-flame-sprayed cylindrical implants were inserted in each lateral antral wall. Three groups of 18 maxillary sinuses each were augmented with s-DFDB, h-DFDB and autogenous bone from the illiac crest, respectively. In the remaining 18 sinuses, the subantral hollow space was left empty. Pull-out tests were carried out after intervals of 12, 16 and 26 weeks. The mean pull-out force needed, irrespective of time, was 259.3 N in the empty control group, 356.7 N in the group augmented with autogenous bone, 278.1 N in the test group augmented with h-DFDB and 365.2 N in the group augmented with s-DFDB, revealing no significant difference between the individual groups (P > 0.05). The implants of the group augmented with autogenous bone showed an increase in the mean pull-out force from 223.8 N after 12 weeks to 523.7 N after 26 weeks. The nonaugmented control group yielded values of 248 N after 12 weeks, which rose to 269.8 N at the last test, while the values of the h-DFDB group increased from 275.4 N to 325.4 N. The highest initial pull-out values were obtained in the s-DFDB group. They amounted to 310.5 N after 12 weeks and rose to 481.4 N after 26 weeks. Time thus proved to have a significant influence on the pull-out forces (P = 0.014) with a statistically proven linear trend (P = 0.007). The findings of this experimental study indicate that the use of homogeneous DFDB in one-stage sinus lift procedures results in a mechanical loading capacity of implants comparable to that achieved by autogenous cancellous bone from the iliac crest. In contrast, the use of heterogenous-DFDB resulted in only slightly higher pull-out forces than those observed in the nonaugmented control group after 26 weeks.
authors.affiliation: Department of Oral Surgery, School of Dentistry, Vienna, Vienna, Austria. robert.haas@univie.ac.at
authors.forename: Robert
authors.initials: R
authors.lastname: Haas
authors.forename: Daniela
authors.initials: D
authors.lastname: Haidvogl
authors.forename: Orhun
authors.initials: O
authors.lastname: Dörtbudak
authors.forename: Georg
authors.initials: G
authors.lastname: Mailath
mesh_terms: D000540:Alveolar Ridge Augmentation / Q000379:methods*; D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D018786:Bone Substitutes / Q000627:therapeutic use; D016025:Bone Transplantation / Q000379:methods*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D016001:Confidence Intervals; D015921:Dental Implants; D017267:Dental Prosthesis Design; D005260:Female; D005612:Freeze Drying; D006801:Humans; D016555:Matched-Pair Analysis; D008437:Maxilla / Q000601:surgery*; D008443:Maxillary Sinus / Q000601:surgery*; D012756:Sheep; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013997:Time Factors; D014021:Tissue Preservation; D014025:Titanium / Q000737:chemistry; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous; D016474:Weight-Bearing
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D015921:Dental Implants; D014025:Titanium