Methods: In this randomized clinical trial, 17 patients (9 male, 8 female) and 30 implants, with collar thread exposure, were entered. Patients with systemic disease (even controlled disease) and poor oral hygiene were excluded. Selection of grafted material for each patient was done randomly using flash cards. After implantation and putting the grafted material on the exposed threads, a collagen membrane was put on it and the surgical site was sutured tightly. In 14 implants bone debris was used and in 16 implants allografts (DBA+MBA, TBI) to cover the exposed threads. The second stage was done at least 2 months later. To save the keratinized gingiva, the tissue punch was not used. Three and 12 months after cementing the crown, three clinical complications were assessed: Collar exposure, Thread exposure, Metal shadow.
Results: Data were analyzed using SPSS software, Pearson Chi-square test, and Fisher's Exact test. In the first follow-up there was no complication. In the second follow-up, there was thread exposure in three implants (18.8%) of allograft group which was not seen in the bone debris group. However, these differences were not statistically significant (P=0.228). There was metal shadow in two implants (14.3%) of bone debris group after 12 months while it was seen only in one implant (6.3%) of allograft group. This difference was not statistically significant (P=0.586). Collar exposure was seen in seven implants (50%) of bone debris group and (43.8%) of allograft group. This difference was not significant either.
Conclusions: Although results of using bone debris and allograft had no statistical difference, in 14 (46.6%) implants one of the mentioned complications arose.