NGHIÊN CỨU ĐẶC ĐIỂM HÌNH THÁI VÀ KẾT QUẢ PHẪU THUẬT LÀM DÀI THÂN RĂNG LÂM SÀNG KẾT HỢP TIÊM BOTULINUM TOXIN Ở BỆNH NHÂN ĐIỀU TRỊ CƯỜI HỞ NƯỚU TẠI BỆNH VIỆN TRƯỜNG ĐẠI HỌC Y DƯỢC CẦN THƠ

Abstract

Background: A gummy smile is a common aesthetic concern that can negatively affect self-confidence and quality of life. Monotherapy approaches often have limited efficacy. Combining clinical crown lengthening surgery with botulinum toxin injection warrants investigation to evaluate comprehensive outcomes and inform clinical decision-making. Objectives: To describe morphological characteristics and evaluate the treatment outcomes of gummy smiles using clinical crown lengthening surgery combined with botulinum toxin injection at Can Tho University of Medicine and Pharmacy Hospital during 2024–2025. Subjects and methods: A cross-sectional descriptive study with clinical intervention was conducted on 32 patients with gummy smiles indicated for combined treatment. The study took place from April 2024 to April 2025. Clinical data were collected through examinations, facial photographs, and standardized measurements. Data were analyzed using SPSS 20.0; statistical significance was determined at p<0.05. Results: Moderate gummy smile (4.1–6 mm) accounted for 56.3%, and severe cases (>6 mm) for 25%. Upper lip shortening at the philtrum was present in 37.5%, and elongated lip at the oral commissure in 50%. A–B line deviation was minimal to moderate at 81.3%. The mean maxillary incisor protrusion was 2.73 ± 1.63 mm. Gingival coverage of the maxillary anterior clinical crowns averaged 21.02%. After one month of surgery, 78.1% of patients achieved favorable crown height gain, and 90.6% maintained healthy keratinized gingiva. At two weeks post-injection, 93.8% of patients had complete resolution of gummy smile, and 56.3% maintained the result at two months. Upper lip mobility decreased from 32.45% to 14.03%. Satisfaction rates were high: 87.5% were very satisfied with their smile, 68.8% with gingival display, and 62.5% with smiling confidence. Conclusion: Clinical crown lengthening combined with botulinum toxin injection significantly improves gummy smile, reduces upper lip mobility, and results in high patient satisfaction.