Hard and soft tissue changes around implants activated using plasma of argon: A histomorphometric study in dog

Objective: To histologically assess the hard and soft tissue changes after insertion of cleaned and activated titanium implants using plasma of argon. Materials and methods: Eight dogs were included in this study. The mandibular premolars and first molars were extracted. For each hemi-mandible, four implants, 7 mm long and 3.3 mm of diameter, with a ZirTi surface were used. The surface of two implants was randomly treated with argon plasma (test), while the other two implants were left untreated (control). After 1 month, the same procedure was performed in the contralateral hemi-mandible. The amount of old bone, new bone, overall value of old bone plus new bone, and soft tissue was histologically evaluated. Results: After 1 month of healing, high percentages of new bone in close contact with the implant surface were found at both the treated (60.1% ± 15.6%; 95% CI 56.5%–78.0%) and untreated (57.2% ± 13.1%; 95% CI 49.3%–67.5%) implants. Low percentages of old bone were found at this stage of healing, at both the treated (4.4% ± 3.0%; 95% CI 1.2%–5.4%) and untreated (3.4% ± 3.1%; 95% CI 0.6%–4.9%) implants. Not statistically significant differences were found between groups (p >.05). After 2 months of healing, treated implants presented a significantly higher (p =.012) new bone formation (72.5% ± 12.4%; 95% CI 69.6%–86.8%) compared to untreated sites (64.7% ± 17.3%; 95% CI 59.4%–83.3%). Controversially, no difference (p =.270) in terms of old bone was present between treated (3.1% ± 1.7%, 95% CI 1.8%–4.2%) and untreated implants (3.8% ± 1.9%, 95% CI 3.2%–5.8%). Significant differences (p =.018) in terms of total mineralized bone were found between treated (75.6% ± 13.0%, 95% CI 73.3%–91.3%) and untreated implants (68.4% ± 16.8%; 95% CI 64.2%–87.6%). Conclusions: Implants treated using plasma of argon was demonstrated to reach a higher bone-to-implant contact when compared to untreated implants.