The study, conducted by Rongjing Fu, Jingjing He, and Di Liu of Guangxi University of Chinese Medicine and Guangxi International Zhuang Medicine Hospital, took advantage of a statistical technique known as frequentist network meta-analysis. Unlike a traditional meta-analysis, which can only compare two interventions head to head, a network meta-analysis simultaneously compares multiple treatments by combining direct comparisons within trials with indirect comparisons across the wider network of studies. This approach is particularly valuable when, as in the case of herbal periodontal adjuncts, most trials compare a single extract against control rather than against each other. The researchers searched major electronic databases and trial registries from their inception through December 30, 2025, and registered their protocol in advance with PROSPERO under the identifier CRD420261336531.

The analysis ultimately included thirty-eight randomized controlled trials, all of which contributed to at least one quantitative synthesis. The team focused on four clinically meaningful endpoints. The primary outcomes were probing pocket depth, the distance between the gum margin and the base of the periodontal pocket, and clinical attachment level, which measures how much of the tooth’s supporting apparatus has been regained. Secondary outcomes were the gingival index, a measure of gum inflammation, and the plaque index, which quantifies bacterial deposits on tooth surfaces. Using Stata 18.0, the authors fitted a random-effects model and expressed results as mean differences with 95 percent confidence intervals, with positive values indicating that the plant extract produced an additional improvement beyond scaling and root planing alone. They also calculated SUCRA values, the surface under the cumulative ranking curve, to rank treatments probabilistically.

The headline finding concerns two botanical agents that stood out for reducing probing pocket depth. Curcumin longa extract, derived from turmeric, was associated with an additional pocket depth reduction of 1.13 millimeters, with a 95 percent confidence interval of 0.44 to 1.82 millimeters, based on a single trial and rated as moderate certainty evidence. Garcinia mangostana, the mangosteen fruit whose pericarp is rich in xanthone compounds with documented antimicrobial activity, showed an estimated additional reduction of 1.00 millimeters, with a confidence interval of 0.43 to 1.56, supported by two trials and also graded moderate certainty. Lycopene, the carotenoid pigment found in tomatoes, along with tea extract and curcumin, also produced statistically detectable reductions in pocket depth, although the effects for tea extract and curcumin fell below half a millimeter and rested on low-certainty evidence.

That half-millimeter threshold matters clinically. Periodontal researchers generally regard changes in probing depth of less than about half a millimeter as difficult to distinguish from measurement variability and unlikely to alter treatment decisions. Effects approaching or exceeding one millimeter, by contrast, could translate into meaningful reductions in pocket depth and improved access for oral hygiene. The findings for Garcinia mangostana and curcumin longa extract therefore represent the most intriguing signals in the dataset, though the authors were careful to note that the curcumin longa estimate rests on a single randomized trial, a fragile foundation for any firm clinical recommendation.

Perhaps the most sobering result concerned clinical attachment level, the outcome that best reflects true regeneration of periodontal support. No plant extract adjunct demonstrated a statistically detectable benefit for this endpoint across the network. In other words, while some botanicals appeared to shrink inflamed pockets, the analysis found no convincing evidence that any of them restored lost attachment of gum tissue to the tooth root. This distinction between reduced inflammation and genuine tissue repair is central to periodontal therapeutics, and it tempers enthusiasm for the pocket depth findings, which could partly reflect reduced gingival swelling rather than structural healing.

The secondary outcomes painted a somewhat more encouraging picture for gum health. Emblica officinalis, also known as Indian gooseberry or amla, along with curcumin and tea extract, showed reductions in the gingival index, indicating less gum inflammation. Curcumin and tea extract additionally reduced the plaque index, suggesting better control of bacterial deposits. These results align with the known pharmacology of these agents: curcumin inhibits inflammatory signaling pathways, tea polyphenols such as epigallocatechin gallate suppress periodontal pathogens, and amla is rich in vitamin C and antioxidant tannins. The SUCRA rankings, however, were treated by the authors as descriptive rather than definitive, and were interpreted alongside effect sizes, certainty of evidence, and the number of studies contributing to each estimate.

Safety data emerged as a conspicuous weakness of the evidence base. Trial-level safety information was available in only twenty-one of the thirty-eight included studies, and the reporting was too heterogeneous and incomplete to support any quantitative comparison of adverse events across interventions. No intervention-related serious adverse event was explicitly reported anywhere in the corpus, which is reassuring at face value, but the authors emphasized that adverse-event and withdrawal reporting was generally incomplete. For therapies that would be applied into open periodontal pockets, often as gels, irrigants, or local delivery systems, systematic safety surveillance is not optional, and the current literature falls short of that standard.

The certainty assessments underpin the study’s cautious conclusions. The authors applied formal evidence grading and found that even the most promising results, those for curcumin longa extract and Garcinia mangostana on pocket depth, reached only moderate certainty, while several other statistically significant findings were supported by low-certainty evidence. Sparse networks, reliance on indirect comparisons, small sample sizes, and heterogeneous formulations all conspired to weaken the inferential foundation. Because of this, the researchers concluded that no intervention can currently be considered optimal, and that the apparent hierarchy of plant extracts should be read as a map of where evidence is strongest rather than a prescription for clinical practice.

What the review does provide is a roadmap for the next generation of trials. The authors call for larger head-to-head randomized controlled trials that directly compare the most promising extracts against one another, rather than against placebo or control alone. They also urge the use of standardized formulations with verified phytochemical content, clinically meaningful endpoints such as attachment level and tooth survival, comprehensive adverse-event reporting, and longer follow-up periods to capture whether short-term gains persist. Until such studies are completed, plant extracts remain an intriguing but unproven layer on top of the proven foundation of scaling and root planing, and patients with periodontitis should continue to regard mechanical debridement and meticulous oral hygiene as the core of therapy, with any botanical adjunct viewed as experimental pending stronger evidence.

Subject of Research: Comparative efficacy of plant extracts as adjuncts to scaling and root planing for periodontitis

Article Title: Comparative efficacy of plant extracts as adjuncts to scaling and root planing for periodontitis: a systematic review and network meta-analysis of randomized controlled trials

Article References: Fu, R., He, J., & Liu, D. (2026). Comparative efficacy of plant extracts as adjuncts to scaling and root planing for periodontitis: a systematic review and network meta-analysis of randomized controlled trials. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05595-w

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05595-w

Keywords: periodontitis, plant extracts, scaling and root planing, network meta-analysis, randomized controlled trials, curcumin, Garcinia mangostana, probing pocket depth, clinical attachment level, gingival index, complementary medicine, oral health