Twenty-three studies were included in the review: 2 before-and-after studies, 6 cross-sectional studies, 10 cohort studies and 5 case-control studies. The number of participants was not reported.
Before-and-after studies: both studies assessed qualitative outcomes. One study scored 3 out of 6 for quality and the other scored 6.
Cross-sectional studies: 5 of the 6 studies evaluated qualitative outcomes; the remaining study evaluated quantitative outcomes. Four studies scored 5 out of 5 for quality and two scored 4. Cohort studies: 4 of the 10 studies used the same follow-up period for both treatment groups. Five studies assessed treatment outcomes using either qualitative or quantitative measures. Two studies scored 2 out of 6 for quality, four scored 3, three scored 4 and one scored 6.
Case-control studies: in most studies, the matching of cases and controls was either incomplete or absent. One study evaluated quantitative outcomes. Four studies scored 3 out of 5 for quality and one scored 4.
The review authors listed the following factors as having a significant influence on treatment outcomes: age (3 studies), marital status (1 study), smoking (1 study), site or extent of resection and oncological stage of lesion (9 studies), site of implant placement (5 studies), type of surgical reconstruction (11 studies) and type of prosthetic reconstruction (10 studies).
The review authors listed the following factors as having no significant influence on treatment outcomes: gender (1 study), economic or social background (1 study), radiotherapy (8 studies), hyperbaric oxygen therapy (5 studies) and implant system used (2 studies).