**2.5.3 Results**

66 Macro to Nano Spectroscopy

**2.5 Estimation of the veloci1ty of the salivary film at different locations in the mouth** 

Although a great deal of information is available about the overall flow rate of whole saliva in man, there is no quantitative information on the velocity of flow of the salivary film in different regions of the mouth. Once secreted into the oral cavity, saliva forms a thin film, approximately 0.1 mm thick, which moves around inside the mouth until it is eventually swallowed. The higher the saliva secretion rate, the more frequently swallowing occurs, and the cleaner the mouth will be remain, However, this salivary film does not distribute evenly

The aim of this study was to estimate of the velocity of the salivary film at different locations

An extraoral device was used to adjust the flow rate of a 0.1-mm-thick film of artificial saliva over an agarose disk to determine the clearance half-time in the same manner as that performed intraorally (Dawes et al, 1989). Then, from the relationship between the intraoral and extraoral half-times, the salivary film velocities of the UAB and UPB sites were estimated. The half-time at UAB and UPB were evaluated by the method of study 2.1.

Fig. 14 shows the equipment used. The diameter of the well in the lower part of the device was 6 mm, the same as the width of the 0.1-mm-deep slot in the upper part. Thus, the fluid was directed over the surface of the gel. The well was 4 mm from the end of the device.

The well in the lower part of the device was filled with 1 mol/L KCl in 1 % agarose, as described for study 2.1 (Fig.3) and the upper and lower parts of the device were held

**2.5.1 Aim** 

in the mouth.

or reach all parts of the mouth.

**2.5.2 Materials and methods** 

together with three spring clamps.


Fig. 14. An extraoral device for salivary flow rate study.

There was a significant difference in the mean clearance half-time for the UAB between unstimulated (51.2 ± 19.3 min) and stimulated (40.1 ± 15.1 min) (P < 0.05) salivary flow rates. A significant difference was also found in the mean half-time for the UPB between unstimulated (19.2 ± 6.9 min) and stimulated (12.1 ± 5.2 min) (P < 0.01) salivary flow rates.

The results on the effect of velocity on the clearance half-time are shown in Table 4. With the flow rates set, the film velocity varied from 0.67 to 100 mm/min. The clearance half-times were inversely related to the velocity of fluid flow, and varied from 2.2 min to 58.3 min.


Table 4. Effect of velocity of fluid flow on the mean half-time ± S.D. for clearance of KCL from an agarose gel, 1.5 mm in depth

Table 5 shows the in vivo clearance half-times for the UAB and the UPB as well as the estimated velocities of flow of the salivary film, as determined from the data in Table 1.

When salivary flow was unstimulated, the velocity of the salivary film of the UAB was estimated as 0.8 mm/min, whereas for the UPB it was estimated as 40.1 mm/min. When

Estimation of the Velocity of the Salivary Film at the Different Regions in the Mouth

of each site in the oral cavity is slso different (Watanabe 2008),

*Research,* Vol.66, No.8, pp. 1300 -1302, ISSN

*Research,* Vol.68, No.11, pp.1479-1482, ISSN

pp 23-34, IRL Press, Oxford, UK

USA

*Research,* Vol.66, No.11, pp.1614-1618, ISSN

*Caries Research,* Vol*.*17, No.4, pp. 321-334, ISSN 0008-6568

**4. Acknowledgment** 

**5. References** 

suggestions and comments.

– Measurement of Potassium Chloride in the Agar Using Atomic Absorption Spectrophotometry 69

The author has also concluded that the velocity of salivary film is different by each site in the oral cavity and the slow velocity of the salivary film over the different surfaces of the teeth will retard clearance from diffusants of plaque such as acid. This suggests that the pH

The author thanks to emeritus proffesor C. Dawes (University of Manitoba) for helpful

Collins, L.M.C., & Dawes, C. (1987). The surface area of the adult human mouth and

Dawes, C. ( 1983). A mathematical model of salivary clearance of sugar from the oral cavity.

Dawes, C. & Watanabe, S., Biglow-Lecomte, P., & Dibdin, GH. (1989). Estimation of the

Duckworth, RM., & Morgan, SN. (1991). Oral fluoride retention after use of fluoride dentifrices. *Caries Research,* Vol.25, No.2 , pp. 123-129, ISSN 0008-6568 Ekstrand, J. Lagerlӧf, F. & Oliveby, A.(1986). Some aspects of the kinetics of fluoride in

thickness of the salivary film covering the teeth and oral mucosa. *Journal of Dental* 

velocity of the salivary film at some different locations in the mouth. *Joural of Dental* 

saliva; In: *Factors relating to demineralization and remineralisation of the teeth.* Leach, SA., & Edgar, WM. (Ed), ISBN 0-947946-73-X , pp 91-98, IRL Press, Oxford, UK Foster, TD., & Hamilton, NC. (1969). Occlusion in the primary dentition. Study of children at 2.5 to 3 years of age. *British Dent Journal, Vol.*126, No.2, pp. 76-79, ISSN Featherstone, JDB., Oreilly, MM., Shariati, M., & Brubler, S.(1986). Enhancement of

remineralisation in vitro and in vivo, In *Factors relating to demineralization and remineralisation of the teeth.* Leach, SA., & Edgar, WM. (Ed), ISBN 0-947946-73-X ,

intraorally or ingested following routine clinical applications of topical fluoride

chloride from artificial plaque at different sites in the mouth. *Journal of Dental* 

*through adolescence.* Pediatric Dentistry, ISBN 0-7216-2106-6, Philadelphia, Saunders,

fluoride from a sodium fluoride tablet following various intraoral dissolution methods. *Journal of Dental Research,* Vol.65, No.7, pp. 1001-1005, ISSN 0022-0345

Heath, K., Singh, V., Logan, R., & McIntyre. J.(2001). Analysis of fluoride levels retained

products. *Australian Dental Journal*, Vol.46, No. 1, pp.24-31, ISSN 00450421 Lagerlӧf, F., & Dawes, C.(1984). The volume of saliva in the mouth before and after swallowing, *Journal of Dental Research.,* Vol.63, No.5 , pp. 618-621, ISSN 0022-0345 Lecomte, P., & Dawes, C.(1987).The influence of salivary flow rate on diffusion of potassium

Pinkham, JR., Casamassimo, PS., Fields, HW., McTigur., DJ., & Nowak, AJ.(1988) *Infancy* 

Primosh, RE., Weatherell, JA., & Strong, M.(1986). Distribution and retention of salivary


salivary flow was stimulated, the velocity of flow for the UAB was estimated as 2.3 mm/min, whereas for the UPB it was estimated as 12.1 mm/min.

Table 5. Estimated velocity of the salivary film at UAB and UPB sites in the mouth
