Difference in Buccal Gingival Thickness between the Mandible and Maxilla in the Aesthetic Zone: A Systematic Review and Meta-Analysis

Abstract

Background: Fragile gingival tissue is a risk factor for the development of gingival recessions. Despite the fact that gingival recessions are more commonly seen around anterior mandibular teeth, previous research has predominantly concentrated on the gingival dimensions in the anterior maxilla. The objective was to systematically compare buccal gingival thicknesses between the upper and lower jaws in individuals with healthy gingival conditions in the aesthetic zone. Methods: A comprehensive search of three databases was carried out until October 2023. Gingival thickness differences between the maxilla and mandible were evaluated by calculating the mean differences along with the corresponding 95% confidence interval (CI). Subgroup analysis was conducted based on the measurement area, measurement method, and tooth category. Results: A total of seventeen studies were included in this systematic review. Eleven studies were included in the quantitative analysis. Quantitative analysis comparing gingival thickness around 2100 teeth in the anterior mandible to 2056 teeth in the anterior maxilla revealed a statistically significant thinner buccal gingiva in the mandible (mean difference: 0.16 mm; 95% CI [-0.24, -0.07]; p = 0.0003). Conclusions: The present systematic review revealed a more delicate buccal gingiva in the anterior mandible. However, further scientific validation is required due to the considerable heterogeneity in study design and the potential presence of confounding variables.

Keywords: aesthetic zone; gingival thickness; periodontal diagnostic; systematic review; transgingival probing; ultrasound measurement.

Figure 1

PRISMA flow diagram for the identification of relevant studies.

Figure 2

Meta-analysis of studies comparing gingival thickness around the anterior teeth between the mandible and maxilla. * Asterix indicates the values of measurements in the subcrestal region. The mean difference of gingiva thickness between the upper and lower jaw is represented as a green dot along a horizontal line, denoting the confidence interval of each study. The collective result from all studies is illustrated by a black diamond, indicating the aggregated effect size. References: Anand et al. 2022 [31], Eger et al. 1996 [4], Han et al. [32], Kydd et al. [30], La Rocca et al. 2012 [40], Lee et al. 2017 [42], Müller et al. 2000 [37], Park et al. 2018 [35], Ranga et al. 2015 [36], Shao et al. 2018 [26], Vandana et al. 2005 [21].