A clear deficiency of many of the studies was the imprecise and inconsistent definitions of implant survival or implant success, as detailed in Table 1. In addition, in a number of studies, the terminology ‘implant success’ and ‘implant survival’ were used interchangeably within the narrative making comparison of the studies challenging and rendering statistical analysis of the survival data inappropriate.

The reporting of implant survival data varied between studies and was presented in a variety of ways which included cumulative survival and implant survival incidence. In some cases, no attempt to estimate survival was made but adequate data was documented to enable its calculation (Table 2). Best practice would be the reporting of cumulative survival to give context to survival (time) and account for patient drop-out which may be high in this particular patient group. Due to the variability in the methods of data reporting and their comprehensiveness, there was insufficient confidence in extracted data to report statistical findings. Notably, as all studies presented different deficiencies in data reporting or study definitions, there was no clear way to further exclude studies using these criteria.

As such, there is a clear need for a consensus on what minimum data set is required for published articles reporting on implant survival in this patient cohort to allow further investigation via systematic reviews (e.g., effect of benign vs malignant H&N cancer and implant survival). The inclusion and exclusion criteria were highly variable, and in some studies, the criteria were such that there was a pre-disposition to selection bias and reporting higher implant survival rates. Patient follow-up was variable and also variably reported but in general was insufficient. Where possible, follow-up of at least 5 years is required to begin to evaluate the outcome of dental implant treatment. Unfortunately, information on long-term dental survival in this cohort is still scarce and the results of the present review should not be extrapolated beyond early implant survival.