Journal of Periodontology, 2026 (SCI-Expanded, Scopus)
Background: We hypothesized that acne vulgaris (AV) and gingivitis were associated through systemic inflammatory mechanisms, sharing common etiological factors. This study aimed to identify the association between AV and gingivitis and to assess changes in acne severity in relation to changes in the plaque index (PI). Methods: This prospective, observational study included 150 patients aged 13 to 19 years, divided into three equal groups based on acne severity. The PI and the gingival index (GI) of all participants were recorded, followed by oral hygiene instruction and scaling. The severe acne group was re-evaluated after 1.5 months, constituting the follow-up stage of the study. These patients were then divided into two subgroups based on the degree of change in their acne scores. Changes in PI and GI were calculated from repeated measurements. Results: At baseline, although no significant difference was observed between the groups in terms of PI scores (p > 0.05), the GI scores were significantly higher in the severe acne group compared with the mild acne group (p < 0.001). At the re-evaluation, the subgroup with more pronounced improvement in acne scores showed significantly greater changes in both GI and PI values (p < 0.001), and the magnitude of these changes demonstrated good discriminative performance for acne improvement (AUCs = 0.896–0.903; p < 0.001). Conclusions: The findings suggested that gingival inflammation was associated with the severity of AV lesions, independent of plaque accumulation. Thus, improvements in gingival inflammation and plaque accumulation were associated with AV-associated symptom improvement. Trial registration: This study was registered in ClinicalTrials.gov under the number NCT06237387 on May 24, 2024. Plain language summary: Acne vulgaris and gingivitis are common inflammatory diseases. Etiological factors such as nutrition, hormonal changes associated with puberty, and hygiene habits are effective in both diseases. This study aimed to examine the relationships among plaque accumulation, gingivitis, and acne vulgaris. A total of 150 adolescents were included in the study, and participants were divided into three groups based on acne severity: mild, moderate, and severe. All participants were assessed for plaque and gingival inflammation, and all received oral hygiene instruction and dental scaling. Greater reductions in plaque levels and gingival inflammation were observed in patients who showed more pronounced regression of acne lesions.