Background: Few comparative studies, with at least 5 years of follow-up, describing the use of implants in prosthetic rehabilitation of partially edentulous patients, are available. There are a few randomized, controlled clinical studies that evaluated the effect of different surface designs of screw-shaped implants on the outcome of the treatment.
Objective: a prospective, randomized, clinically-controlled trial aimed at assessing the outcome of restorative therapy in periodontitis-susceptible patients who, following basic periodontal therapy, had restorations with implants with either machined- or rough surface topography.
Materials and Method: Fifty-one subjects (average age: 59.5 years), 20 males and 31 females who, following treatment of moderate-to-advanced chronic periodontitis, required implant therapy for prosthetic rehabilitation, were chosen. Seventeen of the patients were current smokers. Following the active treatment, all subjects were included
in an individually-designed maintenance program. A total of 56 fixed partial dentures (FPDs) and a total of 149 screw-shaped and self-tapping implants (Astra Techs implants)
83 in the maxilla and 66 in the mandible were performed in a two-stage procedure. Each patient received a minimum of two implants and, by randomization, every second implant inserted was designed with a machined surface, and the remaining one – with a roughened Tioblasts surface. Abutment connection was performed 3-6 months after implant insertion. Clinical and radiographical examinations were performed following FPD connection, once a year, during the 5-year follow-up period. Analysis of the peri-implant bone-level alterations was performed for each subject, at FPD and at the level of the implant .
Results: Four patients and four FPDs were lost during the 5-year surveillance. One implant (machined surface) did not properly integrate (early failure), and was removed at the time of the abutment connection. Three implants were lost during function and further eight implants could not be accounted for at the 5-year follow-up examination. The overall failure rate after 5 years was 5.9% (subject level), 5.3% (FPD level) and 2.7% ( at implant level). Radiographic signs of osseo-integration loss were not found at any of the implants during the 5-year follow-up. During the first year in use, there was recorded an average 0.33 (SD, 0.61) mm loss of marginal peri-implant bone at patient and FPD levels, and 0.31 (0.81) mm, at the level of the implant. During the following 4 years, the peri-implant bone-level alterations were not numerous.
Conclusion: The present randomized, clinically-controlled trial, performed on partially edentulous periodontitis-susceptible subjects, demonstrated that: bone loss (i) during the first year of functioning, as well as annually thereafter, was small, and (ii) there were not significant differences between implants with machined-surfaces and those with rough surface.Keywords:
- bone loss
- clinical trial
- dental implants