Research Corner - Changes in Osseous Morphology Following Non-SurgicalPeriodontal Therapy: A Possible Paradigm Shift for theTreatment of Intrabony Defects?
Mr Alex Pollard, Honorary Editor, has kindly written a precis of a recently published article.
Changes in Osseous Morphology Following Non-SurgicalPeriodontal Therapy: A Possible Paradigm Shift for theTreatment of Intrabony Defects?
Re-thinking intrabony defects: how far can non-surgical therapy take us?
This thought-provoking paper by Nibali and Cortellini (2025) challenges one of the long-held assumptions in periodontology, that non-surgical periodontal therapy is merely a preparatory step before surgery when intrabony defects are present. Instead, the authors invite us to consider whether careful, minimally invasive non-surgical treatment might itself drive meaningful changes in alveolar bone morphology, with important implications for how and when we intervene surgically.
The article is presented as a clinical innovation report, drawing together evidence from longitudinal cohort studies, retrospective analyses and illustrative clinical cases. The focus is on minimally invasive non-surgical periodontal therapy (MINST), particularly approaches that emphasise gentle subgingival instrumentation, biofilm disruption and minimal trauma to the soft tissues. These concepts align with contemporary European Federation of Periodontology guidance and reflect the gradual shift away from aggressive root planing towards biologically driven healing.
The authors summarise consistent clinical outcomes following non-surgical therapy, including probing pocket depth reduction, clinical attachment level gain and reductions in bleeding on probing. Importantly, they go further by highlighting accumulating radiographic evidence suggesting that intrabony defects may undergo measurable morphological change following non-surgical treatment alone. Across multiple studies cited, reductions in radiographic defect depth of approximately 1 to 3 millimetres have been reported over periods of up to twelve months, particularly when minimally invasive techniques are used.
A key strength of this paper is the integration of biological plausibility with clinical observation. The authors discuss how resolution of inflammation, stabilisation of the blood clot and changes in local growth factor expression may allow intrabony defects to heal through bone apposition or re-mineralisation, even in the absence of surgical access. Clinical cases with long-term follow-up are used to illustrate situations where deep pockets associated with intrabony defects resolve to stable, shallow probing depths, with corresponding radiographic improvement.
From a clinical perspective, the most important message may be the proposed shift in treatment sequencing. Rather than reassessing at three months and moving rapidly to regenerative surgery, the authors suggest a phased re-evaluation approach extending to six and even twelve months after non-surgical therapy. This allows time for hard tissue remodelling to occur and may reduce the need for surgery, or at least alter defect morphology in a way that makes subsequent surgical intervention more predictable and less invasive.
That said, this is not a call to abandon surgery altogether. The authors are careful to acknowledge that some sites will continue to require regenerative or reconstructive procedures, particularly where residual deep pockets persist. The value of non-surgical therapy in this context may be in improving tissue quality and defect architecture before surgery, rather than replacing it entirely.
There are, however, important limitations to bear in mind. Much of the evidence discussed is observational, and there are currently no randomised controlled trials directly comparing minimally invasive non-surgical approaches with conventional non-surgical therapy for intrabony defects. Histological evidence in humans is also lacking and whilst radiographic improvements are encouraging, they do not allow us to distinguish definitively between repair and regeneration.
For clinicians in practice, this paper reinforces the importance of delivering high-quality non-surgical periodontal therapy and allowing adequate time for healing before making irreversible decisions. It also encourages us to look more critically at the outcomes of step two therapy, particularly in complex defects, and to resist the temptation to move too quickly to surgery when clinical inflammation has resolved but remodelling may still be ongoing.
Overall, this is a stimulating and clinically relevant paper that reminds us how much healing potential exists within the periodontium when inflammation is controlled and biology is respected. It is likely to prompt reflection and debate, which can only be a good thing for patient-centred periodontal care.