Tilted Implants in the Immediate Loading Rehabilitation of the Maxilla : A Systematic Review

Tilted implants have been proposed as an alternative to traditional protocols in the rehabilitation of edentulous maxillae. The aim of this meta-analysis was to evaluate the outcomes of upright and tilted implants supporting full-arch fixed dentures for the immediate rehabilitation of edentulous maxillae, after at least 1 year of function. An electronic search of databases and a hand search of relevant journals in oral implantology were performed according to PRISMA guidelines through August, 2011. The literature search yielded 1,069 articles. Eleven articles were available for analysis. A total of 1,623 implants (778 tilted, 845 upright) were inserted into the maxillae of 324 patients. Seventeen tilted (2.19%) and 16 upright implants (1.89%) failed during the first year. No significant difference in failure rate was found between tilted and upright implants (p value = 0.52). Marginal bone level results were obtained from 6 studies. A non-significant mean difference between tilted and upright implants was found with regard to bone loss. Tilted implants demonstrated a favorable short-term prognosis in full-arch immediate loading rehabilitations of the maxillae. Randomized long-term trials are needed to better elucidate long-term success of tilted vs. upright-positioned implants. KEY WOrDs: dental implants, immediate dental implant loading, implant-supported dental prosthesis, dental implantation, endosseous, meta-analysis. IntrODuctIOn In recent years, numerous articles have focused on the treatment of edentulous maxillae with immediately loaded implant-supported prostheses (Degidi et al., 2005; Ibañez et al., 2005; Collaert et al., 2008; Bergkvist et al., 2009). However, the presence of the maxillary sinus usually precludes the insertion of long implants into the distal areas of resorbed maxillae. Short implants (< 10 mm) have been proposed (Degidi et al., 2007; Telleman et al., 2011; Annibali et al., 2012), but it is the authors’ opinion that these may inhibit high levels of initial primary stability, considered one of the most important factors for successful osseointegration of dental implants in immediate loading protocols (Nedir et al., 2004). Bone-grafting procedures to increase bone volume may be a viable treatment option, but they often imply demanding surgical procedures and can be associated with complications, morbidity, and high costs. Moreover, they usually preclude the attainment of sufficient primary stability, and delayed loading protocols are needed. To overcome such limitations, implants could be placed in specific anatomical areas, such as the pterygoid region, the tuber, or the zygoma (Bahat, 1992; Balshi et al., 1999; Brånemark et al., 2004). Any of these procedures has considerable surgical risks and possible sinus complications. Moreover, implant emergence is usually unfavorable from the prosthetic point of view, since it is too palatal. Tilting of the implants parallel to the anterior maxillary sinus wall may represent a feasible treatment option (Krekmanov, 2000; Krekmanov et al., 2000; Aparicio et al., 2001; Fortin et al., 2002; Malò et al., 2005; Koutouzis and Wennström, 2007). Long tilted implants (≥ 13 mm) placed in residual bone have been advocated to obtain high levels of initial primary stability, avoiding bone-grafting procedures. Improved implant anchorage can be achieved by benefiting from the cortical bone of the anterior wall of the sinus and the nasal fossa. Additionally, tilting implants can optimize the anteriorposterior spread of the implants to provide satisfactory molar support for a full fixed prosthesis (FFP) of 12 masticatory units (Krekmanov et al., 2000; Bevilacqua et al., 2011). This FFP design also eliminates or reduces the number of cantilever extensions generally seen with vertical implants to obtain the same number of masticatory units. The purpose of the present systematic review was to evaluate the prognosis of immediately loaded full-arch prostheses supported by both upright and tilted Implants in the Immediate Loading rehabilitation of the Maxilla: A systematic review at UNIV OF CALIFORNIA SANTA CRUZ on November 29, 2014 For personal use only. No other uses without permission. jdr.sagepub. com Downloaded from © 2012 International & American Associations for Dental Research 822 Menini et al. J Dent Res 91(9) 2012 tilted implants in the maxillae, after at least 1 yr of function. Implant cumulative survival rate (CSR) and peri-implant bone resorption were investigated.