Labial Repositioning Using Print Manufactured Polymethylmethacrylate- (PMMA-) Based Cement for Gummy Smile

A Smile Reimagined: Gummy Smile Resolution with Cutting Edge Method Using Chu's Gauge and Polymethylmethacrylate (PMMA) Bone Cement

Excessive gingival display (EGD) is one of the most common aesthetic concerns, and its correction often presents a challenge to periodontists. It has a multifactorial etiology, and this article describes a case involving hypermobile upper lip (HUL), altered passive eruption (APE), and vertical maxillary excess (VME). Upon investigation, a positive collum angle and marked subnasal skeletal depression were observed. In this context, it is noted that during a spontaneous smile, the upper lip retracts and gets lodged in this depression. The rehabilitation plan includes included aesthetic crown lengthening via gingivectomy using Chu's proportional gauge for altered passive eruption and filling the subnasal depression by PMMA (polymethylmethacrylate) bone cement. The entire treatment plan was digitalised using cutting edge methods such as computed tomography (CT), cone beam computed tomography (CBCT), and 3D printers for virtual planning of the defect's position, size, and shape. No postoperative complications were reported. After six months, the patient exhibited a harmonious smile with reduced exposed gingiva.

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

Objective

to 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).

Methods

Twelve 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).

Results

The height, thickness, and volume of the PMMA were respectively 12.84 ± 1.59 mm, 3.83 ± 0.53, and 1532.02 ± 532.52 mm3. PMMA significantly decreased GE from 8.33 ± 1.25 mm (T0) to 6.60 ± 0.93 mm (T12) (p < 0.01). NAR was 98.34 ± 9.28° at T0 and increased to 105.13 ± 7.33° 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.

Conclusions

PMMA significantly decreased GE in a 12-month follow-up without influencing adjacent soft tissue anatomical structures.