Crestal Bone Level Changes Around Immediately Placed Implants: A Systematic Review and Meta-Analyses With at Least 12 Months’ Follow-Up After Functional Loading
- Autores: Bassam M. Kinaia, Maanas Shah, Anthony L. Neely, Harold E. Goodis
- Localización: Journal of periodontology, ISSN 0022-3492, Vol. 85, Nº. 11, 2014, págs. 1537-1548
- Idioma: inglés
- Enlaces
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Resumen
Background: Immediate implant placement (IIP) is a successful treatment and has the advantages of reducing time and increasing patient satisfaction. However, achieving predictable esthetic results with IIP presents a challenge because of naturally occurring bone loss postextraction. Therefore, the focused question of this systematic review is: What is the effect of IIP on crestal bone level (CBL) changes after at least 12 months of functional loading? Methods: Extensive literature review of the Cochrane and MEDLINE electronic databases and a manual search up to November 2012 identified eligible studies. Two reviewers independently assessed the study data and methodologic quality using data extraction and assessment forms.
Results: Electronic and manual searches identified 648 relevant publications. A total of 57 articles satisfied the inclusion criteria. Sixteen studies had test and control groups; therefore, meta-analyses could be performed. The results demonstrated better CBL preservation around IIP compared with implant placement in healed/native bone at 12 months [CBL difference of −0.242 (95% confidence interval [CI], −0.403 to −0.080; P = 0.003)]. Similarly, platform switching around IIP showed better results compared with non–platform switching (CBL difference of −0.770 [95% CI, −1.153 to −0.387; P <0.001]). There was no difference in mean CBL changes with regard to one-stage or two-stage IIP protocol (−0.017 [95% CI, −0.249 to 0.216; P = 0.85]) or the use of immediate or delayed immediate implant loading (0.002 [95% CI, −0.269 to 0.272; P = 0.99]).
Conclusions: Meta-analyses showed less CBL loss around IIP compared with implant placement in healed bone. Platform-switched implants showed greater crestal bone preservation than non–platform-switched implants. There was no significant difference in CBL with one- versus two-stage placement or use of immediate versus delayed IIP loading. Although there were statistically significant differences favoring IIP, the small differences may not be clinically relevant. Although IIP showed favorable outcomes for CBL changes, these results should be interpreted with caution because of high heterogeneity among studies.
Traditionally, timing of dental implant placement after tooth extraction has varied over time.1 In the 1980s, implant loading was typically delayed up to 12 months for implant osseointegration.2-4 Advancements in implant surface technology with increased patient expectations helped reduce the total time from extraction to final restoration. This trend gave rise to the idea of immediate implant placement (IIP) for shorter time intervals. Meaningful discussions of IIP are difficult due to lack of appropriate language defining time of placement. Although many early implant placement protocols exist, the proposed classifications by Hammerle et al.5 and Esposito et al.1 (see supplementary Table 1 in online Journal of Periodontology) are widely accepted today.
The first report of IIP was published in 1976 using a step thread tapered implant design placed immediately into fresh extraction sockets.6 In a 1989 study, Lazzara concluded that immediate implants helped preserve the integrity of the extraction socket in humans.7 Although a few studies8,9 appear to support Lazarra’s conclusion, the majority10-13 show that IIP alone cannot prevent bone loss after tooth extraction. This problem is exacerbated by faster bone resorption of buccal bone compared with the lingual plate postextraction.10-13 Marginal and facial bone loss can negatively impact the final esthetics of IIP. Crestal bone loss increases the risk of midfacial recession, papillary loss, and display of a gray hue of underlying implants.13-15 Ideal three-dimensional placement of the IIP can be complicated by socket anatomy that makes the outcome less desirable. Although primary implant stability is a major determining factor in IIP success, several other factors are important in determining crestal bone level (CBL) changes around IIP. These factors may include platform switching (PS),16 time of loading,17-20 one- or two-stage placement,21,22 number of remaining bony walls postextraction,23,24 the gap between implant and buccal bone, and the need for bone augmentation.25,26 Marginal CBL changes around delayed implants are reported to be greatest during the first year of function (1.0 to 1.5 mm) followed by an annual rate of 0.1 to 0.2 mm.2-4 Earlier studies showed greater CBL loss with machined-surface implants compared with recent investigations of roughened surfaces (CBL loss = 0.22 ± 0.42 mm at 12 months and 0.18 ± 0.88 mm at 5-year follow-up).27 Despite attempts, no studies have successfully used a meta-analysis format to evaluate CBL changes in IIP to date.26,28 The most recent systematic review examined survival rates of IIP but did not report CBL changes. Those analyses found higher survival rates for implants placed in healed bone (99.4%) compared with IIP (95.6%).29 The primary reason for inability to perform a meta-analysis was high heterogeneity among the studies where the main objective was to evaluate the survival and success of IIP.26,28,29 Hence, the specific objectives of the current systematic review and meta-analyses is to analyze CBL changes around IIP (Type I and immediate) based on different surgical and implant-related factors.
