Evaluation of Screw-Retained Versus Screw-Cement-Retained Implant-Supported Fixed Prostheses for Marginal Bone Loss and Peri-Implant Soft Tissue Changes: An In Vivo Study

Aim: The influence of prosthetic retention design on early marginal bone loss and peri-implant soft tissue response remains clinically relevant.Screw-retained restorations provide retrievability and eliminate subgingival cement, whereas screw-cement-retained prostheses are designed to combine retrievability with the passive-fit and esthetic advantages of cementation.Purpose: The purpose of this in vivo study was to compare screw-retained and screw-cement-retained implant-supported fixed prostheses in terms of marginal bone loss, plaque accumulation, and bleeding on probing over a six-month follow-up period.Material and methods: Twenty partially edentulous participants restored with implant-supported fixed prostheses were included in this two-group analysis.Ten participants received screw-retained prostheses and 10 received screw-cement-retained prostheses.Marginal bone loss was assessed with cone beam computed tomography at the buccal, lingual, mesial, and distal aspects of each implant at three and six months after loading.Plaque index and bleeding on probing were recorded immediately after loading and at three and six months.Intragroup and intergroup comparisons were performed, and significance was set at P<0.05.Results: Both groups showed a statistically significant increase in marginal bone loss from three to six months at all evaluated surfaces (P=0.001).At three months, screw-cement-retained prostheses showed significantly greater buccal bone loss than screw-retained prostheses (0.480 ± 0.181 mm versus 0.250 ± 0.190 mm; P=0.008).At six months, buccal bone loss remained significantly greater in the screw-cement-retained group (0.650 ± 0.205 mm) than in the screw-retained group (0.380 ± 0.169 mm; P=0.015).No significant differences were observed at the lingual, mesial, or distal surfaces.Plaque index scores were numerically higher in the screw-cement-retained group at three and six months, but the differences were not statistically significant.Bleeding on probing was comparable between groups.Conclusions: Within the six-month follow-up period, screw-retained implant-supported fixed prostheses showed a more favorable buccal marginal bone response than screw-cement-retained prostheses.The screwcement-retained design demonstrated acceptable peri-implant soft tissue outcomes, but it did not show a marginal bone loss advantage over the screw-retained design in this short-term evaluation.