“…Case series have noteworthy methodological weaknesses, and their inclusion in a systematic review may lead to inaccurate suppositions in relation to the review's focused question (Chambrone et al, 2010b). Even in meta-analyses in which no significant heterogeneity was identified, additional forms of bias, such as selection and publication bias, may influence outcomes, as may differences in the timing of radiotherapy (whether it occurred before or after implant placement), radiation dose, the type of implant placed, differences between patients' systemic conditions (smoking status), occlusal factors, and follow-up period.…”