Changes in Peri-implant Marginal Bone Level by Jaw Location: A Systematic Review and Meta-Analysis of 4970 Implants

The purpose of this study was to evaluate the current evidence on marginal bone-level changes (ΔMBL) around internal connection implants with fixed prostheses by jaw location over time. An electronic literature search for ΔMBL (change in marginal bone level) was conducted in 6 databases. The data from the included manuscripts were categorized by jaw sextant of the implants and duration of follow-up (<2 years, 2–5 years, and >5 years). Meta-analyses were performed on groups with at least 5 studies. A total of 1270 records were screened. Full-text review of 413 papers resulted in a total of 46 studies (representing 2259 patients with 4970 implants) included for quantitative synthesis and analysis. The ΔMBL was summarized at 2 time intervals with the following results: <2 years (anterior maxilla = 0.393 mm [95% confidence interval {CI}, 0.172, 0.613], posterior maxilla = 0.468 mm [95% CI, 0.288, 0.648], and posterior mandible 0.559 mm [95% CI, 0.397, 0.72]), 2 to 5 years (anterior maxilla = 0.683 mm [95% CI, 0.224, 1.142], posterior maxilla = 0.645 mm [95% CI, 0.42, 0.87], and posterior mandible 0.563 mm [95% CI, 0.278, 0.849]). There were insufficient studies in the anterior mandible and with follow-up data over 5 years for quantitative synthesis. Within the limitations of this study, location within the maxillary and mandibular jaws does not seem to influence ΔMBL around internal connection bone level implants with fixed restorations. Although there may be a tendency for greater initial remodeling in the posterior mandible followed by long-term stability, additional studies are needed to evaluate this further.