The Effects of Plasma and Salivary Constituents on Dentin Permeability

Abstract

The experiments described in this report were designed to determine the possible influence of plasma and salivary constituents on dentin permeability, in vitro. The results indicate that plasma, serum, and whole (mixed) saliva are all capable of causing immediate reductions in dentin permeability. Individual plasma protein fractions and several different types of bacteria were also effective in reducing the ease with which fluid can move across dentin. These observations may provide a mechanism for the "spontaneous" reductions in dentin sensitivity seen by clinicians following periodontal therapy. J Dent Res 61 (8): 978-981, August 1982 Introduction.Several clinical studies of the efficacy of various treatments for hypersensitive dentin have reported that about 20-30% of the control groups which received either no treatment or sham treatment showed distinct decreases in the magnitude of dentin sensitivity.'4 Similar clinical impressions have been reported by numerous periodontists. They report that dentin sensitivity is a frequent complication of periodontal therapy, but that it rapidly improves in most patients over a period of days to weeks without any treatment.Based on the hydrodynamic theory of dentin sensitivity,5 these observations suggest that the resistance to fluid flow across dentin has increased in those patients who experienced "spontaneous" recovery. According to the hydrodynamic theory of dentin sensitivity, the common denominator of all painful stimuli is fluid movement within dentinal tubules. Removal of cementum from dentin obviously exposes the tubules to stimuli from the oral environment. Conversely, decreases in dentin sensitivity must be due to decreases in the ability of fluid to move within dentinal tubules.6 The most important variable influencing fluid movement through dentin tubules is the functional radius of the tubules,7 since fluid flow varies with the fourth power of the radius. There are several possible mechanisms which may be responsible for decreasing the fluid permeability of hypersensitive dentin. Brannstrdm and Garberoglio8 recently demonstrated that saliva is capable of forming mineralized deposits within exposed dentinal tubules in crown segments worn in removable dentures for three yr. Saliva has the same access to tubules in exposed hypersensitive dentin. The presence of large numbers of bacteria in plaque or saliva offers another mechanism of blocking fluid flow through tubules. Michelich et al. 9 reported that filtration of bacterial suspensions across dentin resulted in an almost total removal of the bacteria from the solution. The bacteria lodged within the tubules decreased the ability of fluid to move across dentin. If this occurred in hypersensitive dentin, the occlusion of tubules would tend to make it less sensitive. Whether this dentin would ever develop active carious lesions is a moot point. A third mechanism that may be responsible for spontaneous recovery of hypersensitive dentin is the adsorption of salivary and/or plasma proteins gaining access to tubu...

Bond Strength of Self-etch Adhesives After Saliva Contamination at Different Application Steps

“…Some studies have reported that proteins in saliva are the main factors responsible for the improper formation of the dentin-adhesive interface when high-molecular-weight macromolecules in saliva may diffuse into dentin tubules 7,12,16 and compete with hydrophilic monomers during the hybridization process, reducing the bond strength. 17 Moreover, the salivary pellicle protects dental hard tissues against demineralization caused by acid attacks.…”

Innate Immune Responses of the Dental Pulp to Caries

“…For example, natural antibodies against Streptococcus mutans in serum (18,19) may diffuse extravascularly into dentinal tubules via the dentinal fluid to react with bacterial antigens in carious lesions (20 -22). IgG along with serum-derived proteins such as albumin or fibrinogen can adhere to dentinal tubules and nonspecifically decrease the inward diffusion of antigens (17,23,24). On the other hand, products of the degradation of Igs in dentinal tubules might serve as a nutrient source for the caries pathogens (25).…”

Invasion of Dentinal Tubules by Oral Bacteria

“…The pulp responds initially by mounting an inflammatory response that increases the outward flow of dentinal fluid (Maita et al , 1991;Vongsavan and Matthews, 1994), thereby reducing diffusion of noxious stimuli through the dentinal tubules. Molecules present within dentinal tubules such as albumin, fibrinogen, and IgG have been shown to decrease fluid flow through dentin in vitro (Pashley et al, 1982;Hahn and Overton, 1997). It is therefore likely that dentinal fluid components are involved in host defense, by both interacting directly with bacteria and products, and by reducing the permeability of dentin.…”