At the implant level, BOP reduction was noted to be 74.96% (minimum 0%; maximum 100%) at grafted implant sites and 54.88% (minimum 0%; maximum 100%) at non-grafted implant sites. According to the results of the chi-square test, the mean BOP reduction did not differ significantly between the groups at either the patient (p = 0.778, df = 1, χ2 = 0.079) or the implant (p = 0.515, df = 1, χ2 = 0.422) level (Fig. 4).

The reduction in the maximum PD (mm) values between the 2 groups is presented in Table 4. At the patient level, reduction in the maximum PD values amounted to 1.57 mm (minimum − 1.0 mm; maximum 4 mm) and 2.20 mm (minimum: − 4.0 mm; maximum 6.0 mm) at grafted and non-grafted sites, respectively. At the implant level, the corresponding reduction in the maximum PD values were calculated to be 1.31 mm (minimum − 4.0 mm; maximum 4.0 mm) at grafted implant sites and 2.10 mm (minimum − 4.0 mm; maximum 6.0 mm) at non-grafted implant sites. For the between-group comparison, no significant difference could be detected between the groups at both the patient (p = 0.968, df = 1, χ2 = 0.002, chi-square test) and implant (p = 1, df = 1, χ2 = 0.00026, chi-square test) level (Fig. 5).