Do you need to graft a jumping gap >2 mm? Practical takeaways from a randomized trial of injectable β‑TCP

In a 16‑patient randomized trial, filling jumping gaps larger than 2 mm with injectable β‑tricalcium phosphate did not change implant stability at 6 months, though CBCT radiodensity was higher in grafted sites — interpret cautiously and choose grafting selectively at the chair.

Immediate implant placement leaves a “jumping gap” between the implant surface and socket wall; whether to graft gaps larger than 2 mm remains a frequent practical dilemma. A new randomized controlled trial enrolled 16 patients who received 39 immediate maxillary anterior/premolar implants in sites with jumping gaps >2 mm and randomized patients 1:1 to no grafting or to an injectable β‑tricalcium phosphate (β‑TCP) putty placed around the implant. All patients completed 6‑month follow‑up. ([link.springer.com](

The trial’s primary outcome was implant stability (ISQ) at 6 months. There was no statistically significant difference in ISQ between grafted and non‑grafted groups at any time point and the group×time interaction for ISQ was non‑significant (p=0.49). ISQ rose over time in both groups, meaning implants continued to gain stability during healing regardless of graft use. The study included 39 implants (control 20, test 19) in 16 patients. These key numbers and outcomes come from the trial report. ([link.springer.com](

Secondary radiographic measures gave a mixed picture. Periapical grayscale on standardized radiographs rose faster in the grafted group on unadjusted analysis but lost significance after baseline adjustment. On 6‑month CBCT the grafted sites showed significantly higher radiodensity (mean 1224.0 ± 237.0 arbitrary units versus 931.9 ± 100.4 in controls; mean difference 292.1; 95% CI 87.7–496.5; p=0.010). The authors caution this CBCT finding was a secondary outcome, not included in the original sample‑size calculation, and may partly reflect residual graft material rather than more mature bone. ([link.springer.com](

How does this fit with prior evidence? Systematic reviews and meta‑analyses of immediate implants show that socket/gap grafting tends to reduce horizontal buccal bone loss (about 0.5–0.6 mm on pooled estimates) and modestly preserves mid‑facial soft tissue levels, but effects on implant survival or ISQ are small or inconsistent. Those pooled data support considering grafting to protect ridge contour, especially in the esthetic zone, while recognizing the magnitude of benefit is modest. ([pubmed.ncbi.nlm.nih.gov](

Practical chair‑side translation for a modest clinic. First, measure the gap: preop CBCT planning is ideal but a calibrated periodontal probe intraoperatively will tell you whether the horizontal gap exceeds 2 mm. Achieve good primary stability by engaging apical/palatal bone (longer or slightly palatally positioned osteotomy) — the trial used this approach and still left controlled buccal gaps. If the buccal plate is intact and you have a thick phenotype, it is reasonable to accept a 2–3 mm gap without grafting in non‑esthetic posterior sites provided primary stability is excellent and you can monitor closely. If the buccal plate is thin, you are in the esthetic zone, or you must preserve ridge contour for future prosthetics, grafting the gap is reasonable — an injectable β‑TCP putty adapts well to irregular defects and is usable without specialist membrane techniques. The trial used simple measures familiar to most clinics (injectable β‑TCP putty, gelatin sponge over the platform, interrupted sutures, and a single preoperative antibiotic dose). ([link.springer.com](

Technique pointers and cautions. Do not overpack the gap (avoid excessive pressure against the buccal plate), use a hemostatic sponge where needed, and avoid assuming CBCT radiodensity equals mature bone — residual graft can raise radiodensity early on. Explain to patients that grafting mainly aims to preserve contour and soft tissue support rather than to increase early mechanical stability. Finally, remember this RCT is small (16 patients) and powered for ISQ only with 6‑month follow‑up; its radiographic secondary outcomes need confirmation in larger trials before changing standard practice. ([link.springer.com](