Dataset - Effect of Glycerin Application on the Surface Hardness of Composite Resins

This dataset was developed to test the hypothesis that the application of glycerin prior to light-curing improves the surface hardness of composite resins by minimizing the oxygen-inhibited layer and enhancing the polymerization process. The dataset includes both in vitro and clinical studies that compared surface hardness values of composite resins with and without prior glycerin application.

The data comprises key variables extracted from eligible studies, including author and year of publication, country of origin, study design (in vitro or clinical), type of composite resin, glycerin application details (concentration, timing, and method), light-curing protocol, surface hardness testing method (e.g., Vickers or Knoop), pre-test storage or clinical conditions, and quantitative results for surface hardness (mean and standard deviation). Risk of bias was assessed using appropriate tools based on the study type (RoBDEMAT for in vitro and ROBINS-I for non-randomized clinical studies).

The findings reveal a consistent trend across most included studies, showing higher surface hardness values in the glycerin-treated groups. This supports the hypothesis that glycerin application can improve polymerization outcomes. However, variability in testing protocols, resin types, and glycerin formulations suggests the need for further standardization.

The data were systematically extracted by calibrated reviewers using a standardized Excel spreadsheet and subsequently exported to RStudio (latest version) for quantitative analysis. All procedures followed PRISMA guidelines. This dataset can be reused for meta-analyses, subgroup analyses by resin type or test conditions, and methodological comparisons across studies. Clear variable labels and consistent formatting enable straightforward interpretation and integration into related research.

All included data are available in English and were obtained from full-text articles retrieved from indexed scientific databases. No synthetic or simulated data were used.