Effects of polymethyl methacrylate-based bone cement graft for treating excessive gingival display and its dimensional facial changes: 12-month clinical study

Abstract

Objectiveto present a 12-month follow-up with photographic and tomographic analyses of the effect of polymethyl methacrylate-based bone cement graft (PMMA) in gingival exposure (GE) in patients with excessive gingival display (EGD). MethodsTwelve patients with EGD were included. The PMMA was surgically placed. A frontal and lateral photograph protocol was performed at baseline (T0), 3 (T3), 6 (T6), and 12 months (T12) post-operatively. Soft tissue cone-beam computed tomography (ST-CBCT) was performed at T0 and T12. Measures included GE, length of the lip vermilion (LLV), lip shape (LS), nose width (NW), filter width (FW), nasolabial angle (NAS) while smiling, and nasolabial angle at rest (NAR). The height, thickness, and volume of the cement graft were also measured in the ST-CBCT. The comparisons were performed by Kruskal-Wallis test at 5% of significance (p<0.05). ResultsThe height, thickness, and volume of the PMMA were respectively 12.84±1.59mm, 3.83±0.53, and 1,532.02±532.52mm3. PMMA significantly decreased GE from 8.33±1.25mm (T0) to 6.60±0.93mm (T12) (p<0.01). NAR was 98.34±9.28º at T0 and increased to 105.13±7.33º at T12; however, the angle value was not statistically different (p=0.08). LLV, LS, NW, FW, and NAS did not exhibit statistical differences between the baseline and follow-up periods. ConclusionsPMMA significantly decreased GE in a 12-month follow-up without influencing adjacent soft tissue anatomical structures.