Complex sentence: Most of these methods result in an increase in the amount of vermilion visible, but so far, quantitative data exists only for the V-Y lip augmentation, for which statistically significant increases in upper vermilion height and surface area have been measured.
Split into simpler sentences: Most of these methods result in an increase in the amount of vermilion visible. Quantitative data exists for the V-Y lip augmentation, for which statistically significant increases in upper vermilion height and surface area have been measured.