**2.3.2.1 Location of the parotid duct orifice**


These were 35 consenting adults (20 men, 15 women) with a mean age of 27.1 years (range, 23-35 years). They had a complete dentition up to the second molar and no malocclusion. In each subject, plaster models were made after taking impressions of the upper and lower dentitions.


Before taking an impression of the parotid duct orifice, a 2-mm hole was made at the centre of an adhesive therapeutic agent for aphthous stomatitis (Aftach; Teijin, Tokyo) and the agent was placed on the mucosa so that the hole matched the parotid duct orifice. Next, using a vinyl siloxane impression material (Stat BR; Car Japan, Tokyo), an impression of the buccal tooth surfaces and mucosa around the Aftach was taken with the teeth in centric occlusion to localize the duct opening in relation to the teeth.


To take standard photos, a horizontal reference plane was set for each maxillary plaster model. This was a triangular plane defined by the occlusal plane at the maxillary midline and the distobuccal cusp of the left and right maxillary first molars.


The standard plane was set horizontally and the plaster model was matched with the impression of the parotid duct orifice. In order to take standard photos from the same angle, the line connecting the disto- and mesio-buccal interdental papillae of the maxillary first molar was set orthogonal to the imaging direction.


After defining the reference plane on standard photos as the X axis and the line perpendicular to the X axis passing through the distal plane of the first molar as the Y axis, the location of the parotid duct orifice was measured in relation to the reference point.

In one subject the location of one parotid duct was determined six times in order to assess the reliability of the method.

### **2.3.2.2 Oral clearance on the buccal surface of the upper molar region**


Subjects comprised 12 (8 men, 4 women mean age 28.3 years) of the original 35 subjects whose parotid duct orifice fell within 1 SD of the mean values for the X and Y coordinates obtained in Study 2-3-2-1.


The subjects had not eaten for at least one hour prior to the study and the studies were done in either the mid-morning or mid-afternoon. In the 12 subjects for whom oral clearance was measured, Lashley cups were attached over the left and right parotid duct orifices and with the agar holders in position, parotid saliva was collected on 5 separate occasions for a 5-min period without stimulant.


Oral clearance was assessed using the same methods of the study 2-1. 1% agar containing 1 mol/l potassium chloride was placed into cylinders (diameter, 4 mm; depth, 1 mm) held by an acrylic holder (width, 30 mm; height, 10 mm; thickness, 2 mm). The open surfaces of the cylinders were initially covered with microscope slides to allow the agar to set. In each agar holder, 3 cylinders were placed horizontally at 6-mm intervals (Fig. 9).

Fig. 9. Agar holder

60 Macro to Nano Spectroscopy

These were 35 consenting adults (20 men, 15 women) with a mean age of 27.1 years (range, 23-35 years). They had a complete dentition up to the second molar and no malocclusion. In each subject, plaster models were made after taking impressions of the upper and lower

Before taking an impression of the parotid duct orifice, a 2-mm hole was made at the centre of an adhesive therapeutic agent for aphthous stomatitis (Aftach; Teijin, Tokyo) and the agent was placed on the mucosa so that the hole matched the parotid duct orifice. Next, using a vinyl siloxane impression material (Stat BR; Car Japan, Tokyo), an impression of the buccal tooth surfaces and mucosa around the Aftach was taken with the teeth in centric

To take standard photos, a horizontal reference plane was set for each maxillary plaster model. This was a triangular plane defined by the occlusal plane at the maxillary midline

The standard plane was set horizontally and the plaster model was matched with the impression of the parotid duct orifice. In order to take standard photos from the same angle, the line connecting the disto- and mesio-buccal interdental papillae of the maxillary first

After defining the reference plane on standard photos as the X axis and the line perpendicular to the X axis passing through the distal plane of the first molar as the Y axis, the location of the parotid duct orifice was measured in relation to the reference point.

In one subject the location of one parotid duct was determined six times in order to assess

Subjects comprised 12 (8 men, 4 women mean age 28.3 years) of the original 35 subjects whose parotid duct orifice fell within 1 SD of the mean values for the X and Y coordinates

The subjects had not eaten for at least one hour prior to the study and the studies were done in either the mid-morning or mid-afternoon. In the 12 subjects for whom oral clearance was measured, Lashley cups were attached over the left and right parotid duct orifices and with

**2.3.2 Materials and methods** 



the reliability of the method.

obtained in Study 2-3-2-1.




dentitions.

**2.3.2.1 Location of the parotid duct orifice** 


occlusion to localize the duct opening in relation to the teeth.

molar was set orthogonal to the imaging direction.


and the distobuccal cusp of the left and right maxillary first molars.

**2.3.2.2 Oral clearance on the buccal surface of the upper molar region** 

The cylinders were attached to the teeth using Hydroplastic (TAK, Tokyo) so that the central cylinder would be on the buccal surface of the first molar, at the coordinates of the mean X and Y values obtained in Study 2-4-2-1. After salivary secretion stabilized, which took about 1 minute when parotid flow was measured with a Lashley cannula, the Parafilm was removed to initiate the experiment. On separate occasions, the holder was retained for 5, 10, 20 or 40 min without stimulant. At each time point, the concentration of residual potassium in the agar was measured for calculation of the half- time (the time for half of the potassium chloride to diffuse from the gel), as described by the study 1. Concentrations of potassium were measured by removing the agar cylinders from the holder, soaking each in 300 ml of 100 ppm sodium chloride solution for 90 min, and measuring the levels of eluted potassium by atomic absorption spectroscopy using an ANA-182 spectroscope (Tokyo Koden, Tokyo). The experiment was performed 3 times on both sides of each subject, and mean values were calculated. During the experiment, subjects were asked to refrain from touching the agar holder with their tongue or talking.
