TY - JOUR
T1 - Change in crown-to-implant ratio of implants placed in grafted and nongrafted posterior maxillary sites
T2 - A 5-year prospective randomized study
AU - Nedir, Rabah
AU - Nurdin, Nathalie
AU - Huynh-Ba, Guy
AU - Bischof, Mark
N1 - Funding Information:
The authors gratefully acknowledge the International Team for Implantology (ITI) Foundation for its financial support (grant no 428/2005). They have no conflicts of interest to declare.
Publisher Copyright:
© 2019 by Quintessence Publishing Co Inc.
PY - 2019
Y1 - 2019
N2 - Purpose: The aim of this study was to evaluate the performance of implants placed for 5 years in grafted vs nongrafted sinuses in relation to crown-to-implant ratio. The measurements of crown and implant lengths took into account changes in both endo-sinus and crestal bone levels over 5 years. Materials and Methods: Enrolled patients required one or two implants in at least one sinus and presented a residual bone height of posterior maxilla ≤ 4 mm. Individual sinuses were randomly allocated either to be grafted or not before surgery. Implants of 8 mm in length were placed using osteotome sinus floor elevation (OSFE). After 10 weeks of healing, they were loaded functionally using definitive single crowns. Radiographic measurements were made on periapical radiographs taken at surgery, prosthetic steps, and 5 years. The implant length was measured between the most apical and coronal contact of bone and implant, and the crown length was measured between the most occlusal point of the crown and the crestal bone. Data were analyzed using mixed linear models. Results: Twenty implants were placed in grafted sinuses and 17 in native bone (12 patients). One of the 35 restored implants failed. Immediately after surgery, the mean lengths of the implants placed in grafted and nongrafted sites were 2.4 ± 0.8 and 2.7 ± 0.9 mm, respectively (P = .351). At loading, the mean crown-to-implant ratios were 3.8 ± 0.8 and 4.6 ± 2.0 (P = .033), respectively, whereas at 5 years, they were 2.0 ± 0.8 and 2.1 ± 0.4, respectively (P = .341). Conclusion: The use of grafting material is not necessary to restore posterior maxilla ≤ 4 mm with OSFE and simultaneous implant placement. Over 5 years, all restored implants but one were functional. Despite unfavorable conditions in terms of initial bone anchorage and height of single crown restoration, a high initial crown-to-implant ratio did not compromise the long-term survival of implants placed in grafted or nongrafted sinuses.
AB - Purpose: The aim of this study was to evaluate the performance of implants placed for 5 years in grafted vs nongrafted sinuses in relation to crown-to-implant ratio. The measurements of crown and implant lengths took into account changes in both endo-sinus and crestal bone levels over 5 years. Materials and Methods: Enrolled patients required one or two implants in at least one sinus and presented a residual bone height of posterior maxilla ≤ 4 mm. Individual sinuses were randomly allocated either to be grafted or not before surgery. Implants of 8 mm in length were placed using osteotome sinus floor elevation (OSFE). After 10 weeks of healing, they were loaded functionally using definitive single crowns. Radiographic measurements were made on periapical radiographs taken at surgery, prosthetic steps, and 5 years. The implant length was measured between the most apical and coronal contact of bone and implant, and the crown length was measured between the most occlusal point of the crown and the crestal bone. Data were analyzed using mixed linear models. Results: Twenty implants were placed in grafted sinuses and 17 in native bone (12 patients). One of the 35 restored implants failed. Immediately after surgery, the mean lengths of the implants placed in grafted and nongrafted sites were 2.4 ± 0.8 and 2.7 ± 0.9 mm, respectively (P = .351). At loading, the mean crown-to-implant ratios were 3.8 ± 0.8 and 4.6 ± 2.0 (P = .033), respectively, whereas at 5 years, they were 2.0 ± 0.8 and 2.1 ± 0.4, respectively (P = .341). Conclusion: The use of grafting material is not necessary to restore posterior maxilla ≤ 4 mm with OSFE and simultaneous implant placement. Over 5 years, all restored implants but one were functional. Despite unfavorable conditions in terms of initial bone anchorage and height of single crown restoration, a high initial crown-to-implant ratio did not compromise the long-term survival of implants placed in grafted or nongrafted sinuses.
KW - Atrophic posterior maxilla
KW - Crown-to-implant ratio
KW - Dental implants
KW - Grafting material
KW - Osteotome sinus floor elevation
KW - Proximal bone-to-implant contact
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U2 - 10.11607/jomi.6766
DO - 10.11607/jomi.6766
M3 - Article
C2 - 31528866
AN - SCOPUS:85072293376
SN - 0882-2786
VL - 34
SP - 1231
EP - 1236
JO - The International journal of oral & maxillofacial implants
JF - The International journal of oral & maxillofacial implants
IS - 5
ER -