Influence of Sinus Floor Configuration on Grafted Bone Remodeling After Osteotome Sinus Floor Elevation

• Autores: Hsuan Hung Chen, Yi-Chun Lin, Shyh-Yuan Lee, Lien-Yu Chang, Bor Jian Chen, Yu Lin Lai
• Localización: Journal of periodontology, ISSN 0022-3492, Vol. 88, Nº. 1, 2017, págs. 10-16
• Idioma: inglés
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• Resumen

  • Background: This study investigates influence of the sinus floor configuration on dimensional stability of grafted bone height after the osteotome sinus grafting procedure.

    Methods: Forty single-tooth dental implants inserted after placement of bioglass and/or allograft into the sinus area using an osteotome technique in 37 patients were evaluated in this retrospective study. Periapical radiographs were taken using the long-cone technique before and after implant placement. Specifically, radiographic measurements of grafted bone height at the mesial and distal side of each implant were taken, and the sinus floor configuration was classified into concave, angle, and flat according to the sinus floor profile at the implant site. Furthermore, the intruding angle, defined as the angle between the implant axis and sinus floor, was measured.

    Results: All implants were clinically stable during a mean follow-up period of 39.2 months. Mean initial gain of sinus grafted bone height was 7.0 ± 1.9 mm, and later it was reduced to 4.6 ± 1.9 mm at follow-up (P <0.001). A greater reduction in grafted bone height was revealed in the flat sinus group compared with the concave group (P <0.001). Results from the linear regression showed larger intruding angles were statistically significantly associated with a greater reduction in grafted bone height (r2 = 0.55, P <0.001).

    Conclusion: All bioglass and/or allograft placed in the maxillary sinus after the osteotome technique underwent remodeling and shrinkage; however, the outcome of the procedure was more predictable in sinuses with a concave floor and small implant-intruding angles.

    Resorption of the alveolar ridge after loss of posterior teeth and pneumatization of the maxillary sinus often leads to an insufficient residual bone height for implant placement over the posterior maxillary region.1 Sinus augmentations have been developed to elevate the maxillary sinus membrane and augment bone volume.2,3 The lateral window technique and the transalveolar technique using the osteotome are the two main approaches for sinus grafting procedures.4 The transalveolar technique, which creates a “green-stick fracture” of the sinus floor prior to implant placement, was first suggested by Tatum.5 Later, Summers6,7 proposed a sinus floor elevation technique using a set of tapered osteotomes to elevate the sinus floor and prepare the implant site. The osteotome technique was considered less invasive compared with the lateral window approach.2 However, it still showed highly predictable results, with a survival rate between 93.5% and 97.4%, comparable with implants placed in native bone.4,8-12 It has been reported that the grafted area apical to the implant undergoes remodeling and shrinkage after the osteotome sinus grafting procedure.12,13 Brägger et al.12 assessed the bone tissue remodeling pattern after placement of a mixture of deproteinized bovine bone mineral and autologous bone chips in the sinus area. Their results showed apical graft height in the mesial and distal surfaces of the implants was 1.52 and 1.43 mm, respectively, at surgery but was reduced significantly to 0.29 mm at both surfaces after 12 months. Another investigation from the same study group using implants inserted with deproteinized bovine bone mineral showed the reduction of apical graft height from 2.7 mm to 2.1 mm at 1 year post-surgery, which further decreased to 1.9 mm at the 3-year follow-up.13 French et al.14 divided the sinus floor “contour” into four groups: flat, concave, angle, and septa. Effect of the implant failure was not found to be statistically significant between groups; however, it is still of interest to note that more implant failure was observed in flat sinus floors, with a rate of 1.9%, about twice that compared with all the other contours that were between 0% and 1% (concave, angle, and septa). Although no study has assessed influence of sinus floor configuration on the patterns of grafted bone remodeling to date, the aim of this retrospective study was to compare dimensional stability of grafted bone after the osteotome sinus grafting procedure in the maxillary sinus with different sinus floor configurations.