115 Salivary film thickness and MUC5B levels In addition, participants completed the Regional Oral Dryness Inventory (RODI) to measure the intra-oral perceived dryness [8, 9]. This questionnaire contains 9 schematic illustrations of different locations in the oral cavity. Four illustrations represent areas in the upper jaw: the upper lip, anterior part of the palate (including the rugae), inside part of the cheeks and posterior part of the palate (from the rugae up to the end of the soft palate). Four illustrations represent areas in the lower jaw: the lower lip, floor of the mouth, posterior part of the tongue (from vallate papilla up to end of the tongue) and anterior part of the tongue (from the tip of the tongue up to vallate papilla). Finally, one illustration represents the pharynx. At each location, the patient can indicate the severity of the perceived oral dryness using a 5-point Likert scale ranging from 1 = “no dryness” to 5 = “severe dryness” [9, 10]. Sialometry and salivary pH To limit circadian variations, the salivameasurements were performed between 8:15 and 10:15 A.M in the same room (temperature 20–24 ℃, humidity 50–70%) [28]. The participants were instructed not to eat, drink, chew gum, brush teeth, use mouthwash or smoke at least 1 h before their visit. The unstimulated (UWS) and chew-stimulated salivary flow rates (CH-SWS) were determined as described previously [29]. The pH of saliva was measured immediately after saliva collection using an electronic pH metre (PHM240, pH/ion metre, Meterlab, Copenhagen, Denmark). The samples were kept on ice until analysed. Determination of the palatal surface area In order to measure the palatal surface area, an intra-oral scan of the upper jaw including the palate (the whole hard palate and part of the soft palate) was taken using a TRIOS 3 scanner (3Shape, version 21.3.5, Copenhagen, Denmark) using the manufacturer’s protocol. Scans were digitally saved as Polygon File Format (PLY) files. Subsequently, each PLY object was analysed twice in Meshmixer (Autodesk, San Rafael, CA, USA) by one researcher (ZA). This analysis involved the manual separation of the palate by using the vibrating line including visible fovea palatine as a cut-off for the length of the palate. Besides, all palatal mucosa including the gingiva around the upper teeth were included in the palatal surface. After segmentation, the palatal surface areas (in mm2) were determined. 6
RkJQdWJsaXNoZXIy MTk4NDMw