Razaghi N, Gill T, Patankar A, et al. Significance of primary stability in non-immediate loaded dental implants: a systematic review & meta-analysis. Int J Prosthodont 2025; 38(4): 457–482.

This systematic review and meta-analysis considers the importance of primary stability in implant dentistry. The study questions the thought that, without primary stability at implant placement, micromotion of the implant may result in higher failure rates. Following implant placement, osteoclastic activity gradually reduces the primary stability of the implant, while new bone production and osseointegration of the implant results in increasing secondary stability given time. Stability is measured based on the resonance frequency analysis (quantified as the implant stability quotient (ISQ)) and insertion torque of the implant. The paper dichotomously considers ISQs below 60 or insertion torques below 35Ncm to be low stability for the purpose of the analysis. 

The PICO question considered in this review was: ‘In patients requiring an implant-supported restoration treated with non-immediate loading protocol, are there differences in survival of implants placed with primary stability (IT ≥35 Ncm or ISQ ≥60) and those not achieving primary stability (IT <35 Ncm or ISQ <60)?’ Of the 1,237 abstracts screened, 79 articles were included in the study, requiring relevant inclusion criteria such as a minimum of 10 human participants, non-immediate loading of implants and measurement of ISQ or insertion torque at the time of placement.

Seven studies were included for meta-analysis (utilising a random effects model), which concluded that there was no evidence an ISQ below 60 resulted in an increased implant failure rate, or that an insertion torque below 35Ncm resulted in an increased implant failure rate. The paper suggests that in certain cases lower ISQ/insertion torque at placement may in fact be advantageous as a result of lower osteoclast activity with reduced necrotizing bone and faster secondary stability development. 

The paper concludes that many studies have demonstrated high and equivalent implant survival rates irrespective of the primary stability at implant placement. Based on this systematic review and meta-analysis, there was no clear association between primary stability and implant failure, and there was no stability threshold for increased failure rates of implants. It is important to note that this is for non-immediately loaded implants only, whereas immediate loading has a clear need for primary stability.

Lombardi T, Rapani A, Ezeddine F, et al. Clinical outcomes of bone-level and tissue-level short implants placed in posterior maxilla: a case–control study. Clin Implant Dent Relat Res 2025; 27(1): e13428.

The maxillary antrum can provide a challenge when placing implants in the posterior maxilla; the solutions include sinus elevation, angled implant placement and the use of short implants. This paper was a case–control study looking at 59 consecutive patients rehabilitated with 74 implants. These were subdivided into bone level (7mm) or tissue level (5–6.5mm). The paper’s primary outcome was looking at physiological bone remodelling (PBR) at placement, restoration (T1) and 12 months post loading (T2).

The paper suggests that a stable peri-implant marginal bone level is an important indicator of implant success. The loss of bone in this area can be more catastrophic in short implants because of a proportionally higher reduction in support. The factors influencing bone remodelling include abutment height, emergence profile, number of prosthetic disconnections and the micro-gap. The micro-gap has been managed with two strategies: a horizontal platform switch in bone-level implants (through the movement of the zone of inflammation away from the bone crest) and a vertical platform switch in tissue-level implants. 

The implants for this study were placed in three separate centres and followed up for one year post-loading. The tissue-level implants were the test group, and bone-level implants the control group. The null hypothesis being that there was no difference in peri-implant marginal bone loss after one year of function between the groups. The measurements for bone levels were taken radiographically by two calibrated examiners; the study was sufficiently powered as per the sample size calculation for the primary outcome. The mean PBR around tissue-level implants was lower (0.11mm vs 0.34mm) at T1, with p = 0.004 – suggesting statistical significance. Similarly, at T2 PBR was lower for tissue-level implants (0.30mm vs 0.55mm) and was statistically significant (p = 0.003). A secondary outcome showed a positive correlation for PBR with the use of a short prosthetic abutment (<2mm) and thin mucosal thickness (<2mm) for both groups. Additionally there was positive correlation with PBR and an emergence profile angle of the crown >30° for the bone-level group.

Despite the results for PBR, it is important to note that both implant groups had high survival rates and good marginal bone stability after a year of loading and are viable options for rehabilitation in the posterior mandible. 

Cuozzo A, Arora M, Marini L, et al. Differential response to non-surgical periodontal therapy between intrabony and suprabony defects: a retrospective analysis. J Clin Periodontol 2025; 52(8): 1158–1166.

As per the latest S3 periodontal guidelines, Step 1 and Step 2 of periodontal therapy involves education and patient motivation followed by PMPR. This is a non-surgical periodontal therapy (NSPT) approach. Pocketing can be divided into suprabony (horizontal) defects (where the base of the pocket is at the level of the bone crest) and intrabony (vertical) defects (where the base of the pocket is apical to the alveolar bone crest). The paper retrospectively assessed 200 consecutive patients treated within a single centre for periodontal outcomes following NSPT. The study compared the outcomes of NSPT in intra/suprabony defects. The outcome measures were pocket depth reduction and pocket closure, which was defined as a residual pocket <5mm with no bleeding
on probing. 

Both types of bony defect responded to NSPT, with a pocket reduction (mean) of 0.72mm for the suprabony group and 0.91mm for the intrabony group. While this appears to show a greater reduction in the intrabony group, this is down to the deeper baseline pocketing in these defects. It is expected from the literature that sites with a deeper initial pocket should see greater levels of reduction and clinical attachment gain. Looking at pocket closure, a suprabony defect was 2.60× more likely to close in comparison with an intrabony defect, where multilevel analysis was utilised to adjust for site, tooth and patient-related effects. Additionally, when modelling was utilised, there was 0.6mm greater pocket reduction in surabony defects compared with vertical defects. 

It should be noted that the study considered the short-term follow-up only (three months post-treatment) and that there were varying levels of operator skill, from undergraduates to specialists.