The science of a radiant smile: toward a systematic review
Authors
Paola Bassi, Gregorio Menozzi, Guido Galbiati, Chiara Dini, Paolo Cressoni, Alessandra Laforgia, Sabina Saccomanno, Maral Di Giulio Cesare, Claudia Ciocia, Andrea De Giacomo, Franceska Vinjolli, Edit Xhajanka
Abstract
Background: A pleasing smile is shaped by tooth color, alignment, the relationship between teeth and gingiva, and patient-centered factors such as self‑esteem. Narrative reviews about smile aesthetics frequently summarise the literature without clearly describing search strategies, inclusion criteria, or risk‑of‑bias assessment. This lack of reproducibility weakens the scientific validity of the conclusions.
Objective: To transform the previous narrative review on The Science of a Radiant Smile into a systematic review with reproducible methods. We aimed to synthesize evidence on interventions and factors influencing smile aesthetics, including tooth whitening, veneers, digital smile design, management of excessive gingival display, principles of smile design, and psychosocial determinants. We also limited the reference list to ≤65 sources.
Methods: The review followed the PRISMA 2020 guideline [8]. Searches were conducted in PubMed, Scopus, Web of Science, and Cochrane Library up to May 2026. Inclusion criteria were (1) clinical trials, observational studies, or systematic reviews examining interventions or factors affecting smile aesthetics; (2) adult or adolescent human participants; (3) full‑text articles in English. Exclusion criteria were case reports, letters, and non‑human studies. Two reviewers independently screened titles and abstracts, assessed full texts, and extracted data. Risk‑of‑bias was assessed using the NIH quality assessment tool for observational and interventional studies. Because of heterogeneity in study designs, results are presented narratively and, where available, pooled estimates from existing meta‑analyses are reported.
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