A rough surface implant neck with microthreads reduces the amount of marginal bone loss: a prospective clinical study

Objectives: An intra‐individual controlled clinical trial was conducted to evaluate and compare the amount of marginal bone loss (MBL) found around implants of a comparable design, with or without retention grooves (microthreads) or polished necks, during the early stages of healing. Materials and methods: Forty‐eight (48) patients with missing mandibular posterior teeth were treated with two commercially available implants of the same brand (MIS): one with microthreads (S‐model) and the other with a polished neck (L‐model). MBL around each implant was measured on follow‐up radiograms taken 4 months after placement (exposure and crown cementation), and 6 and 12 months after loading. Results: Forty‐six (46) patients completed the study, making 46 implant pairs available for statistical analysis. None of the implants failed to integrate. All the implants displayed some extent of bone loss throughout the follow‐up period. At each time point (exposure, 6 and 12 months after loading), the S‐model implants displayed statistically significant lower amounts of bone loss (0.22 vs. 0.76, 0.57 vs. 1.22 and 0.9 vs. 1.5 mm, respectively). Other than the type of the implant, no correlation was found between MBL and the implant stability values (PerioTest), dimensions, site of insertion or any of the other collected variables. Conclusions: Implants with a roughened neck surface and microthreads are more resistant to MBL during the first phases of healing, as compared with implants with a polished neck.