LAUSR

PURPOSE To establish a digital assessment method for changes in gingiva morphology following initial periodontal therapy. METHODS Ten periodontal-healthy participants were selected, and digital models obtained by intraoral scanning and digitizing conventional impressions. Using dentition as a reference, best fit alignment between digital models was carried out. Root mean square (RMS) was calculated to evaluate differences in models, and gingival volume discrepancy (GVD) was calculated after combining separated models. Trueness of intraoral scanning used on the gingiva was evaluated using RMS and GVD between intraoral and conventional models with conventional models as references; precision was evaluated among different intraoral models of one participant. Twenty-three periodontitis-affected participants underwent intraoral scanning immediately after supragingival scaling and two weeks after initial periodontal therapy. The GVD of gingiva between two digital models was calculated to assess gingival changes and related factors after therapy. RESULTS Trueness of intraoral scanning used on the entire gingiva was 83.65 ± 14.43 μm; precision was 70.71 ± 25.58 μm; GVD error measured by digital models was 15.28 ± 10.00 mm³. Gingival volume in periodontitis-affected participants decreased 104.04-1155.09 mm³ after therapy. Probing depth, bleeding index, and keratinized gingival width positively correlated with changes in gingival volume. CONCLUSION Intraoral scanning can be recommended as a method of evaluating morphological changes in gingiva.