However, in two studies (Teoh et al., Burgess et al.), no statistical significance was found despite higher implant failure.

Primary and secondary implant placement and implant survival

Six studies clearly reported the use of both primary and secondary implant placement within their study (Fenlon et al., Ch’ng et al., Zou et al., Burgess et al., Watzinger et al., Wu et al.); however, only one study (Fenlon et al.) reported on implant survival in primary and secondary implant placement within autogenous bone grafts. Felon et al. reported on implant survival in immediate vs delayed placement of the implant fixtures into free vascularised grafts and found that implant survival of immediately placed implants was significantly worse than that of implants placed after a delay of 3 months in free vascularized grafts.

Cancer diagnosis and implant survival

With regards to cancer type (malignant vs benign), three studies (Schultes et al., Watzinger et al., Klein et al.) reported exclusively on implant survival in patients with malignant H&N cancers with varying implant survival rates being reported, whilst one study reported exclusively on benign H&N cancer patients (Wang et al. ) with a 100% implant survival rate being reported (Table 2). Two studies (Fenlon et al., Burgess et al.) provided non-descriptive terms (cancer, head and neck neoplasia) for the type of H&N cancer of the patients within their studies and therefore differentiation between benign and malignant disease could not be made. The other 14 studies reported on both malignant and benign H&N cancers; however, the implant survival data was not reported or presented in a way in which comparison of implant survival in patients with malignant or benign H&N cancers could be made.