Evaluation of the Peri-Implant Bone Level around Platform-Switched Dental Implants: A Retrospective 3-Year Radiographic Study

Abstract

Objective: To describe remodeling of the mesial and distal marginal bone level around platform-switched (PS) and platform-matched (PM) dental implants that were sandblasted with large grit and etched with acid over a three-year period.

Materials and methods: Digital periapical radiographs were obtained at the following time-points: during Stage I of the surgical placement of dental implants, before loading, immediately after loading (baseline), and one, three, six, 12, and 36 months after loading for measuring the horizontal and vertical marginal bone levels.

Results: Sixty implants were successfully osseointegrated during the overall observation period. Vertical marginal bone levels for the PS and PM dental implants were 0.78 ± 0.77 and 0.98 ± 0.81 mm, respectively, whereas the horizontal marginal bone levels for the PS and PM implants were 0.84 ± 0.45 and 0.98 ± 0.68 mm, respectively. During the time leading up to the procedure until 36 months after the procedure, the average vertical marginal bone level resulted in less bone loss for the PS and PM groups-0.96 ± 1.28 and 0.30 ± 1.15 mm, respectively (p < 0.05). The mean levels of the horizontal marginal bone also showed increases of 0.48 ± 1.01 mm in the PS and 0.37 ± 0.77 mm in the PM groups from the time before loading until 36 months after the procedure. However, these increases were not statistically significant (p > 0.05).

Conclusion: PS dental implants appeared to be more effective than PM implants for minimizing the mean marginal vertical and horizontal marginal bone loss during the three-year period. Regardless of which abutment connection was used, the dental implant in the present retrospective investigation exhibited minimal marginal bone remodeling, thus indicating long-term stability.

Keywords: dental implant; peri-implant bone level; platform switching.

Figure 1

Study timeline.

Figure 2

Radiographic measurements of platform-switched implants. (a) Platform-matched (PM) dental implants, (b) platform-switched (PS) dental implants. Vertical marginal bone loss, VMBL; horizontal marginal bone loss, HMBL.

Figure 3

Radiographic follow-up images of dental implants. (a) Platform-switched dental implant in lower left area immediately after prosthetic delivery. (b) Radiographic view of the same dental implant in the lower left area at a three-year follow-up, with no apparent bone remodeling. (c) Platform-switched dental implant in the lower right area immediately after prosthetic delivery, (d) Radiographic view of the same dental implant in lower right area at three-year follow-up, with minimal bone remodeling.

Figure 4

Measurements for mean vertical and horizontal marginal bone loss over the 36-month follow-up period. Variations in the mean vertical and horizontal marginal bone loss before and up to 36 months after loading. (a) The mean vertical marginal bone loss measurements over the 36-month period for PS implants. (b) The mean horizontal marginal bone loss measurements over the 36-month period for PS implants. (c) The mean vertical marginal bone loss measurements over the 36-month period for PM implants. (d) The mean horizontal marginal bone loss measurements over the 36-month period for PM implants.

Figure 5

Mean vertical and horizontal bone gain at 6, 12, and 36 months, reported as standard error. Asterisks (*) indicate a statistically significant difference (p < 0.05).

Figure 6

Ratio of the bone supported surface along the implant fixture over the 36-month period. Percentage of bone contact along the implant for 36 months of follow-up in the PM and PS implants. Asterisks (*) indicate a statistically significant difference (p < 0.05).