In the present meta-analysis, the location of wide-diameter implants did not impact survival. This was in agreement with Degidi et al. whose study did not find a statistically significant difference in the survival of wide-diameter implants in varying bone densities in the maxilla and mandible. However, this was contrary to some studies that reported a lower wide-diameter implant survival in the posterior mandible compared to the maxilla. This was postulated to be due to the low marginal bone vascularity of the mandible. And, this was also contrary to some other studies, which reported a better outcome for immediately placed implants placed in the mandible because of better bone density and quality.

The various lengths of wide implants used in the six selected study ranged from 6 to 16 mm, and the following implant lengths assessed in the meta-regression were 6, 7, 8, 8.5, 10, 11.5, 13, and 16 mm. Unlike our meta-analysis which focused solely on the wide-diameter implant, very few studies looked at the effects of different lengths on the survival rate specific to the wide-diameter implant. Most studies reported survival rates of the shorter implant lengths (≤10 mm) with varying diameter implants (3.75, 4, 5, and 6 mm). Studies by Deporter et al. included different diameter implants and were not limited to only wide-diameter implants; these studies also found no significant effect of implant length on implant performance. Conversely, Olate et al, who also included different diameter implants, observed the largest failure in their short implants compared to long or medium implants. However, Olate et al. evaluated 1649 implants retrospectively, 295 were wide-diameter implants (17.9 %), 1217 were regular-diameter (73.8 %), and 137 were narrow-diameter implants (8.3 %). Thus, their conclusion would pertain more to the regular-diameter implants which makes up the majority of implant evaluated in their study. This would seem to indicate that length may have an effect on regular-diameter implant survival, but this would require further investigation. Our meta-regression, which evaluated the prospective data of a total of 306 wide-diameter implants with lengths ranging from 6 to 16 mm, concluded that wide-diameter implants ranging in length from 6 to 16 mm would not have any significant effect on the implant survival. It should be stressed that stringent inclusion criteria were applied for study selection, and hence, these results cannot be generalized to patients with medical or oral compromise.