# Periodontal Health Parameters in Adults: The Role of the Vestibular Fornix Depth
## 2 Materials and Methods  
The present study is an anatomical and clinical study with a descriptive purpose on the association between vestibular fornix depth, width of keratinized gingiva, and periodontal health. The present research adopted the same investigation approach as previous studies [3; 4]. From October 2020 to May 2021, we enrolled a convenient sample of 100 volunteers from among the undergraduates and postgraduates attending courses in dental hygiene, dentistry, and dental prosthetics at the School of Dentistry of the University of Padua (Italy). Since there was no a priori formal hypothesis that could be the basis for a sample size calculation, the sample size could not be calculated with mathematical methods and a convenient sample of 100 subjects was considered adequate to obtain reliable results and allow for a sound statistical analysis. The study was conducted in accordance with the principles of the Declaration of Helsinki and all participants gave their consent. The study was approved by the local Ethical Committee (No. 84/2022). The inclusion criteria were:  
* aged over 18 years;
* complete upper and lower anterior dentition (teeth from 1.5 to 2.5, and from 3.5 to 4.5);
* no incongruuous anterior restorative crowns coming into contact with the gum margin;
* an absence of macroscopically evident skeletal malocclusions;
* no diabetes or pregnancy; no use of anticonvulsants, calcium antagonists, or immune-modulating drugs;
* periodontal tissues in good health with a plaque index (PI) \(\leq\)15%; bleeding on probing (BOP) \(\leq\)10%; and a pocket probing depth (PPD) \(\leq\)3 mm. We also recorded participants' smoking habits and smoking frequency, whether they had previously undergone any orthodontic treatments, and whether female participants used oral contraceptives. Each participant was fitted with a bilateral mouth-opener and the following measurements were taken:  
Pocket probing depth (PPD)--recorded with the millimetric PCP UNC 15 periodontal probe (Hu-Friedy, Chicago, IL, USA) on the vestibular surface of each front tooth (from 1.3 to 2.3, and from 3.3 to 4.3), coinciding with the medial point of the gum margin. The measurements were rounded up or down to the nearest millimeter (Figure 1);  
The O'Larey plaque index (PI) and bleeding on probing (BOP)--recorded at a total of 6 sites (3 vestibular and 3 palatal/lingual) for each anterior tooth in the upper and lower jaws, using a graduated periodontal probe (bleeding was assessed within 10 s of removing the probe);  
Gum phenotype--recorded in accordance with previously published reports [9]; the measurement was taken by inserting the probe in the vestibular sulcus in a direction parallel to the long axis of the tooth. If the probe was clearly visible through the gingival tissues, participants were assigned to the group with a thin gum phenotype; if not, their gum phenotype was classified as thick (Figure 2);  
Gum recession--calculated at the point of greatest concavity along the gum margin or at the medial vestibular point, measuring the distance between the cemento-enamel junction and the gum margin with the PCP UNC 15 periodontal probe (Hu-Friedy, Chicago, IL, USA);  
Width of keratinized gingiva--as described elsewhere in the literature, a PCP UNC 15 probe was first placed horizontally on the alveolar mucosa, perpendicular to the long axis of the tooth, then moved coronally, dragging the soft tissue towards the keratinized gingiva to locate the muco-gingival junction precisely [10]. The distance from the medial point of the vestibular gum margin to the muco-gingival junction was recorded (Figures 3 and 4);  
Fornia depth--we measured the distance from the medial point, or point of maximum concavity, of the gum margin to the mucobuccal fold. A digital caliper was used to obtain an accurate measurement, which was rounded up or down to the nearest millimeter. The dental arches were kept in gentle occlusion, and the mouth-opener in the frontal position to maximize the depth of the fornix (Figure 5).