Table 1.

Inclusion and exclusion criteria

Category	Included	Excluded
Population	Participants with facial defects who required or had received prosthetic rehabilitation. Facial defects of any underlying etiology, extent, or recency. No age restrictions.	Participants with facial defects not requiring prosthetic rehabilitation. Studies of participants with ocular prostheses only.
Intervention	Studies of facial prostheses with any retention method, manufacturing technique, or materials.	—
Comparator	For comparative studies, any treatment for facial defects, no treatment, or unaffected comparator group.	—
Outcomes	Any evaluation of facial prosthesis provision. Any adverse effects.	Prevalence or etiology of facial defects.
Study type	Systematic reviews with meta-analysis. Experimental studies. Observational studies. Health economics studies. Mixed methods studies.	Nonsystematic literature reviews and systematic reviews without meta-analysis. Case reports, case studies, and case series with fewer than 5 participants. Conference abstracts with inadequate information regarding methodology or outcome measures. Laboratory based in vitro studies. Letters.
Characteristics	Studies originating from any country.	Studies published before 1980. Studies not available in full-text English after reasonable attempts to obtain.