In this study, the point at which gingival thickness (GT) should be measured was investigated. Measurements were made from three different points. It was classified as thin and thick in two ways, according to the average of these three different points and the point corresponding to the base of the gingival groove, which is frequently used in the literature. And these two classifications were compared.

The morphology of the soft tissue around the teeth (buccolingual GT and keratinized gingival width) is defined as the "gingival phenotype". One of the most important considerations when assessing gingival phenotype is the objective quantification of GT, and various methods have been used to measure GT. However, there is no clear consensus in the literature regarding the anatomical point where GT is measured in the buccal region. For this reason, it is thought that measurements made from different points also affect the classification of gingival phenotype. The aim of this study was to investigate the cut-off values in clinical parameters according to the average GT value of different measurement points and the GT value at a single point.

The study was designed as cross-sectional study. Participants were divided into two groups based on thin and thick gingival phenotypes in two different classifications. The first classification was based on the GT measurement taken from the base of the gingival sulcus, while the second classification was based on the average of GT measurements taken from three points (base of the gingival sulcus, 1 mm apical to the base of the gingival sulcus, and 2 mm apical to the base of the gingival sulcus. Other clinical and morphological parameters of the participants, who were divided into two groups (thin and thick) according to these classifications, were also measured with a digital caliper and periodontal probe. These parameters are keratinized gingival width (KGW), gingival groove depth (SD), crown width (CW), crown length (CL), crown width/crown length (CW/CL), papilla height (PH), gingival angle (GA). is. Among these parameters, the unit of measurement for GA is angle. CW/CL is the ratio. Other measurements were measured in mm. For all parameters, cut-off values were obtained through statistical measurements made according to two classifications. And these measurements were compared. In addition, the compatibility of the GT measurements of the three points with each other was also examined.

Participants Ondokuz Mayis University's Clinical Research Ethics Board approved the consent form and study protocol (210/2021). Participants with 1195 teeth sites, were enrolled in the study from September 2022 to August 2023. Participants were recruited from University Ondokuz Mayis included patients, dental/ hygiene students. A single calibrated examiner (SY) performed all clinical and morphological measurements.

Inclusion Criteria:

• Non-smokers
• Healthy and normal periodontia
• Participants with no evidence of dental caries, crown shape alterations, or restorations affecting the occlusal edge in the teeth
• Presence of at least one tooth representing the anterior, molar and premolar regions in the maxillary and mandibular segments

Exclusion Criteria:

• Presence of gingival recession
• Presence of restorations affecting the crown shape and the occlusal edge of the tooth
• Using any medication that may affect the thickness of periodontal soft tissues (cyclosporine A, phenytoin or calcium channel blockers)
• History of orthodontic treatment
• Craniofacial asymmetry
• History of periodontal surgery
• Presence of abrasion or attrition in the incisal area of the teeth