Saliva substitutes in combination with highly concentrated fluorides and brushing: in vitro effects on enamel subsurface lesions.

Hyposalivation is often associated with high caries activity, in particular in patients undergoing irradiation in the head/neck area. Besides the use of saliva substitutes to relieve the oral symptoms, daily application of fluoride gels or toothpaste (5,000 µg F⁻/g) is recommended for caries prevention. The aim of this study was to evaluate potentially remineralising effects of these fluoride agents in combination with saliva substitutes on enamel subsurface lesions. Demineralised bovine specimens were either stored in mineral water [control; saturation with respect to octacalcium phosphate (S(OCP)): 0.8], a demineralising saliva substitute (Glandosane; S(OCP): 0.3) or in a modified (with respect to S(OCP)) saliva substitute [Saliva natura (SN); S(OCP): 1.9] for 5 weeks (37°C). The following treatments were applied twice daily (11-13/group): no treatment (0), ProSchmelz fluoride gel (PS; 10 min application), Duraphat toothpaste (DP; 10 s; brushing with toothpaste/storage solution slurry), combination of DP+PS. Mineral parameters before/after storage were evaluated from microradiographs. Storage in Glandosane led to significant demineralisation (p < 0.05; paired t test), whereas additional use of fluoride agents neutralised the demineralising effect (p > 0.05). Storage in water alone resulted in no changes in mineral parameters (p > 0.05), whereas in combination with fluorides remineralisation could be shown (p < 0.05). For SN alone, remineralisation was observed (p < 0.05), but no additional beneficial effects of fluorides were detected. Under the conditions chosen, the fluoride agents reduce the demineralising effects of Glandosane and promote the remineralisation of specimens stored in water. Remineralising effects of SN could not be enhanced by the fluorides.

Effects of carboxymethyl cellulose-based saliva substitutes with varying degrees of saturation with respect to calcium phosphates on artificial enamel lesions.

The aim of the present study was to evaluate the effects of experimental saliva substitutes based on carboxymethyl cellulose (CMC) differing in degrees of saturation with respect to calcium phosphates on the mineral loss of enamel in vitro. Demineralized bovine specimens (subsurface lesions) were exposed to one of six experimental CMC-based solutions with theoretical degrees of saturation with respect to octacalcium phosphate (S(OCP)) of S0, S0.5, S1, S2, S4, and S8 for 10 weeks. A previously studied saliva substitute (Glandosane) and two aqueous solutions (C0 and C1) served as controls. Mineral losses and lesion depths before and after storage were evaluated from microradiographs. Free and bound calcium as well as phosphate and fluoride concentrations were determined. According to these measurements, S(OCP) of S2, S4, and S8 was 0.3, 1.1, and 3.4, respectively. Storage in Glandosane and both negative controls resulted in significant demineralization (p < 0.05). Only S2 significantly remineralized the specimens (p < 0.05). All other solutions showed neutral effects. No significant differences in mineralization between S0 and C0 as well as between S1 and C1 could be observed (p > 0.05). It can be concluded that a CMC-based solution actually unsaturated with respect to octacalcium phosphate (S2) shows most pronounced remineralization capability under the conditions chosen. This might be explained by a more favorable balance between calcium bound to CMC in an adsorbed layer at the enamel-liquid interface and heterogeneous nucleation of calcium phosphates within a solution compared to solutions either supersaturated or having lower levels of saturation.

Evaluation of the remineralizing capacities of modified saliva substitutes in vitro.

OBJECTIVE: In this in vitro study the effects of various calcium and phosphate additions to a commercially available saliva substitute on remineralization of demineralised dentin were investigated. DESIGN: Bovine dentin specimens (n=70) were prepared. Before and after demineralisation (37 degrees C, pH 5.0, 5 days), one-quarter of each specimens surface was covered with nail varnish (control sound/demineralised tissue). Specimens were exposed either to original Saliva natura (SN 0) or to three modified versions (SN 1, SN 2 and SN 3) formulated with different degrees of saturation with respect to octacalciumphosphate (OCP) and dicalcium phosphate dihydrate (DCPD) for 2 and 5 weeks (37 degrees C). An aqueous solution (Buskes remineralizing solution) served as positive control (PC). Differences in mineral loss (deltadeltaZ) and lesion depth (deltaLD) before and after storage were evaluated from microradiographs. RESULTS: After both storage periods dentin specimens immersed in SN 0 revealed significantly higher mineral losses (indicated by deltadeltaZ) and higher lesion depths (indicated by deltaLD) compared to all other solutions (p<0.05; ANOVA). Specimens stored in SN 1 and 3 showed significantly higher mineral losses compared with PC (p<0.05). No differences could be observed between SN 2 and PC (p>0.05). Only SN 2 significantly remineralized from 2 to 5 weeks storage (p<0.05; t-test). CONCLUSIONS: An experimental Saliva natura solution (SN 2) with S(OCP)=2 and S(DCPD)=1.4 showed highest remineralizing capacity. Similar or better remineralization could not be achieved with slightly higher or lower saturated solutions.

[Modification of the mineralizing capacity of a saliva substitute (saliva natura) on enamel in vitro]. / Studie zu den Modifikationen der mineralisierenden Eigenschaften eines Speichelersatzmittels.

PURPOSE: This in vitro study investigated the effects of exposure to modified (with respect to calcium phosphate saturation) solutions of a commercial available saliva substitute (Saliva natura) on mineralization of enamel in vitro. METHODS: Bovine enamel specimens were prepared. Before and after demineralization (pH 4.95, 14 d, 37 degrees C), one-quarter of each specimen's surface was covered with nail varnish (control of sound/demineralized tissue). Specimens were exposed either to original Saliva natura [saturation with respect to octacalciumphosphate (S (OCP)): 0.03, pH 5.8] or to three lab-produced Saliva natura modifications (S (OCP): 1, 2, 3, pH 6.0) for two and five weeks (37 degrees C). An aqueous solution (S (OCP): 2.7, pH 7.0; Buskes remineralizing solution) served as positive control. Differences in mineral losses (DeltaDeltaZ) and lesion depths (DeltaLD) before and after storage were evaluated from microradiographs. RESULTS: After two weeks storage no differences among the solutions with regard to DeltaDeltaZ and DeltaDeltaLD could be observed (p>0.05; ANOVA). Five weeks storage in original Saliva natura resulted in significantly lower DeltaDeltaZ values compared to all other solutions (p<0.05). No differences with respect to DeltaDeltaZ among the modified solutions (S (OCP) 1, 2, 3; p>0.05) could be observed, whereas storage in the remineralizing solution resulted in higher DeltaDeltaZ values compared to all other solutions (p<0.05). For DeltaLD similar results could be revealed. However, no differences between the remineralizing solution and Saliva natura S (OCP) 2 could be shown (p>0.05). CONCLUSION: Saliva natura with an S (OCP) of 2 showed the highest remineralizing capacities. More pronounced remineralization could not be achieved with a higher S (OCP) of 3 under the conditions chosen.

Effect of carboxymethylcellulose-based saliva substitutes on predemineralised dentin evaluated by microradiography.

OBJECTIVE: This study investigated the effect of six lab-produced saliva substitutes based on carboxymethylcellulose (CMC) differing in octacalciumphosphate saturations (OCP-s) on mineralisation of bovine dentin in vitro. DESIGN: Dentin specimens were prepared (n=234); prior to and after demineralisation (37 degrees C; pH 5.0; 7 d), one-third of each specimen surface was covered with nail varnish (control of sound dentin). Subsequently, specimens (n=13) were exposed to either one of the six CMC-based solutions (OCP-s: 0, 0.5, 1, 2, 4, and 8) at pH 6.5 or to Glandosane for 5 and 10 weeks (37 degrees C). Two aqueous solutions (OCP-s: 0 and 1) served as controls. After storage, thin sections were prepared and mineral loss was calculated by transversal microradiography. RESULTS: After both storage periods specimens immersed in Glandosane revealed a significantly increased mineral loss compared to all other solutions (p<0.05; Bonferroni post hoc test). Control solution with OCP-s=1 induced a significant remineralisation (p<0.05; adjusted paired t-test). Only after 5 weeks exposure to the CMC-based solution with an OCP-s=2 a significant remineralisation compared to baseline (p<0.05) as well as a significantly increased mineral gain of the surface area compared to higher saturated solutions (p<0.05; Bonferroni post hoc test) could be observed. CONCLUSIONS: CMC seems to hamper dentin remineralisation, although after 5 weeks a mineral gain could be induced with slightly supersaturated CMC-solutions with respect to OCP.

[In vitro analysis of an new saliva substitute (Saliva natura) on enamel and dentin]. / In-vitro-Studie zur Untersuchung eines neuen Speichelersatzmittels (Saliva natura) auf Schmelz und Dentin.

BACKGROUND: Hyposalivation is an important chronic side effect of radiotherapy in the head and neck area, and patients often alleviate their symptoms using saliva substitutes. The aim of this study was to evaluate the effects of two commercially available saliva substitutes (Saliva natura and Glandosane) on the mineral loss of bovine enamel and dentin in vitro. An aqueous remineralization solution served as control. METHODS: Each 45 bovine enamel and dentin specimens were prepared. Prior to (control of sound dentin) and after (control of demineralized dentin) demineralization (37 degrees C; enamel: pH 4.95; 14 d; dentin: pH 5.0; 7 d) one third of each specimens surface was covered with nail varnish. Subsequently, the specimens (n = 15) were exposed to Glandosane and Saliva natura as well as a remineralization solution for 14 days (37 degrees C). Specimens were examined using transversal microradiography. RESULTS: Compared to Saliva natura and the reminerlization solution, Glandosane induced both significantly increased mineral losses as well as lesion depths of the enamel specimens (p < 0.05; ANOVA, Bonferroni). After exposure of the dentin specimens to Saliva natura a significantly increased mineral loss could be observed (p < 0.001), whereas no differences in mineral loss could be observed for the enamel specimens (p = 0.078; t-test). CONCLUSIONS: Within the limitations of an in vitro study it can be concluded that Glandosane revealed a demineralizing potential on bovine enamel as well as on dentin and should not be recommended for dentate patients. Since Saliva natura has a demineralizing effect on dentin, a further improvement regarding the remineralizing capacity would be desirable.

Effect of various Ca2+/PO4(3-) concentrations of linseed-based saliva substitutes on enamel in vitro.

Remineralization might be hampered by various polymers used in saliva substitutes. Thus, the present study evaluated the effects of various calcium and phosphate concentrations of linseed-based solutions on the mineral loss of pre-demineralized bovine enamel in vitro. A commercially available saliva substitute (Salinum) based on linseed was tested as well. Enamel specimens were prepared from bovine incisors and embedded in epoxy resin. One-third of each sample was covered with nail varnish (control of sound enamel). After demineralization (37 degrees Celsius; pH 5.0; 14 days) another third of the samples was nail-varnished again. Subsequently, the specimens (n = 10) were exposed to 12 linseed-based solutions (Ca(2+) addition 0-2 mM; PO4(3-) addition 0-3.2 mM) at pH 5.5 and 6.5 as well as to Salinum) for 14 days (37 degrees Celsius). The differences in mineral loss between the values prior to and after the storage in the various solutions were evaluated from microradiographs of thin sections (100 mum). The general linear model revealed a significant dependency for the mineral loss on 'calcium' (P = 0.003), but not on 'pH' (P = 0.397) and 'phosphate' (P = 0.094). Salinum) induced a significant greater mineral loss compared with equivalently saturated solutions (P < 0.05; anova, Bonferroni). The solution with the highest calcium and phosphate concentration showed the greatest mineral gain (P = 0.033; paired t-test). The addition of calcium and phosphate seems to have a positive effect on the remineralizing qualities of linseed-based saliva substitutes.