Influence of intermediate abutment height and timing of placement on marginal bone loss in single implant-supported crowns: a 12-month follow-up randomized clinical trial.

OBJECTIVES

To determine the most effective combination of abutment height and timing of placement in reducing marginal bone loss (MBL).

MATERIALS AND

METHODS

54 patients received at least one single screw-retained crown on an implant replacing a posterior tooth (60 implants). Implants were divided into six groups based on intermediate abutment height (1.5 mm, 2 mm, 3 mm) and timing of placement (immediate: surgery 1; delayed: surgery 2): Group A3I (height 3, surgery 1), Group A2I (height 2, surgery 1), Group A15I (height 1.5, surgery 1), Group A3D (height 3, surgery 2), Group A2D (height 2, surgery 2), Group A15D (height 1.5, surgery 2). Mesial and distal linear radiographic measurements were taken at five follow-up points: implant surgery, crown placement (T1), and 3 (T2), 6 (T3), and 12 months after loading (T4). Partial and total MBL were compared between groups.

RESULTS

After 12 months, the lowest MBL was found in groups A3I (0.13 ± 0.11 mm) and A2I (0.24 ± 0.11 mm), with no statistical difference between them. Groups A15I (0.70 ± 0.12 mm), A3D (0.66 ± 0.11 mm), A2D (0.62 ± 0.12 mm), and A15D (0.78 ± 0.11 mm) showed significantly higher MBL than groups 1 and 2, with no statistical difference among them.

CONCLUSIONS

Immediate abutments of 2-3 mm resulted in lower MBL compared to 1.5 mm immediate abutments or any delayed abutments.

CLINICAL RELEVANCE: This study provides data on the optimal combination of intermediate abutment height and placement timing in preventing MBL.

CLINICAL TRIAL REGISTRATION: Clinical trial registration number: NCT06667531. link: https://clinicaltrials.gov/study/NCT06667531 .