Prospective randomized controlled clinical study comparing two dental implant systems: demographic and radiographic results at one year of loading

Abstract

Objective: To compare the clinical and radiographic outcomes of implants and implant-supported reconstructions using a 1-piece (STM) and a 2-piece (BRA) dental implant system.

Material and methods: Sixty patients were randomly assigned to receive STM or BRA implants. The implants restored with fixed or removable prostheses. Baseline measurements (day of loading) and 1-year measurements included demographic and radiological parameters with details of the surgical procedures, type of prosthesis, survival of implants, and marginal bone-level changes. The Mann-Whitney U-test and the paired t-test were used to analyze the data between the two groups and within the groups within 1 year on an implant- and patient-based level.

Results: In all 60 patients, implants were placed and supported 65 final reconstructions (33 BRA, 32 STM). One implant was lost in the STM group at 9 months (98.5% survival rate), none were lost in the BRA group (100%). On the implant level, the median marginal bone levels were -1.02 mm (interquartile range (IQR) 0.41 mm) at baseline and -1.08 mm (0.59 mm) 1 year later (BRA) and -0.51 mm (0.93 mm) and -0.75 mm (1.14 mm) (STM). The patient level values were -0.98 mm (0.47 mm) at baseline and -1.10 mm (0.71 mm) 1 year later (BRA) and -0.43 mm (0.59 mm) and -0.71 mm (0.97 mm) (STM). The differences between the two groups at both time-points were statistically significant in the patient-level analysis with higher bone levels for the STM group (P < 0.05). The changes in mean marginal bone levels on the implant level amounted to -0.05 mm (SD±0.32 mm) (BRA) and to -0.27 mm (±0.52 mm) (STM). Patient-level values were -0.06 mm (± 0.37 mm) (BRA) and -0.25 mm (±0.35 mm) (STM). These differences between the groups reached statistical significance on the patient level with less bone loss in the BRA group (P < 0.05).

Conclusions: Within the first year of functional loading, high survival rates and minimal changes of marginal bone levels were found for both implant systems used.

Keywords: crown; dental implants; fixed, partial, denture; humans; radiographic; survival.