Caries Research

Pereira, A.C.; Verdonschot, E.H.; Huysmans, M.C.D.N.J.M.

doi: 10.1159/000047437pmid: 11275666

The decision to place sealants is a difficult one, and it has been suggested that in a low risk population it may be efficient to wait until caries is detected in the fissure. An invasive sealant technique with fissure preparation may then be indicated. The diagnostic method used in the indication of such a procedure should accurately detect both dentine caries and sound fissures: high sensitivity for dentine caries (at D3 threshold) with high specificity for enamel caries (at D1 threshold). The aims of this study were to assess the diagnostic performance of selected diagnostic methods at normal cut–offs for traditional dentine caries detection and at reduced cut–offs in relation to the desired performance mentioned above, and to assess whether fissure opening allows for accurate visual detection of dentinal caries. Data were obtained from 230 occlusal sites of 101 extracted human molar teeth. Diagnostic methods used on the entire sample were: visual inspection, electrical conductance measurements and laser fluorescence measurements. The sample was then divided into two groups. Group 1 was subjected to visual inspection after application of a dye. Group 2 was subjected to visual inspection after fissure opening only, and after subsequent dye application. Validation was performed by histological investigation. The results with cut–offs normally used in dentine caries detection were roughly in accordance with the literature, except for laser fluorescence. The sensitivity of visual inspection for dentinal caries (D3) was 17% before and 70% after fissure opening. Using reduced cut–offs, a 100% sensitivity (D3) was achieved with 2 methods, but this also resulted in 63 or 87% false positive diagnoses of sound surfaces. Visual inspection and electrical methods both showed a moderate to high sensitivity (D3) with a higher than 50% specificity (D1). It was concluded that visual inspection and electrical methods at reduced cut–offs may aid the indication of invasive sealant treatment. The visual detection of dentinal caries is substantially increased, but not perfect after fissure opening.

Mandari, G.J.; Truin, G.J.; van’t Hof, M.A.; Frencken, J.E.

doi: 10.1159/000047438pmid: 11275667

The present study was aimed at comparing the effectiveness of three minimally invasive restorative treatment approaches for dentinal lesions in occlusal surfaces. The approaches tested comprised a conventional and a modified–conventional treatment and a modified Atraumatic Restorative Treatment (ART). The conventional approach was performed in a university dental clinic whilst the modified–conventional, employing portable equipment, and the modified ART, using hand instruments and a caries removal solution (Caridex^®), were carried out in the field. Using the split–mouth design, 430 matched contralateral pairs of occlusal cavities were restored with amalgam or glass–ionomers in permanent molars of 152 school children by one dental therapist. The restorations were assessed using a modified USPHS–Ryge criteria. After 2 years, the cumulative survival percentages for occlusal amalgam and glass–ionomer restorations were 92 and 96%, respectively. The survival of all restorations in the conventional, modified–conventional and the modified ART group was 96, 96 and 91%, respectively. The survival of occlusal amalgam and glass–ionomer restorations per treatment group was as follows: 94 and 99%, respectively (conventional group); 95 and 97%, respectively (modified–conventional group), and 89 and 93%, respectively (modified ART group). The differences in survival percentage between restorations with amalgam and glass–ionomer, and between the three restorative treatment approaches were not statistically significant. In countries facing scarcity in resources for dental care, ART seems a promising restorative approach to occlusal caries in posterior teeth. However, a longer clinical observation period is required to substantiate this initial conclusion.

Maupomé, Gerardo; Shulman, Jay D.; Clark, D. Christopher; Levy, Steven M.; Berkowitz, Jonathan

doi: 10.1159/000047439pmid: 11275668

Objective: To compare permanent tooth surface–specific progression/reversal changes between fluoridation–ended (F–E) and still–fluoridated (S–F) communities in British Columbia, Canada, over a 3–year period. Methods: D1D2MFS examinations were contrasted for 2,964 schoolchildren in 1993/94 (grades 2, 3, 8 and 9) and 1996/97 (grades 5, 6, 11 and 12). Generalized Estimating Equation (GEE) models explored the relation between progression/reversal changes and fluoridation status, age, gender, socioeconomic status, and dietary/fluoride histories. Results: Within a scenario of low levels of caries overall, few children had multiple surfaces progressing. At least one smooth surface progressed in 31.4% of subjects; at least one pit–and–fissure (PF) surface progressed in 43.1% of subjects. At least one smooth surface reverted in 89% of subjects who had reversible stages; at least one PF surface reverted in 23.8% of subjects who had reversible stages. GEE (smooth) indicated that odds ratios of progression were twice as large in the F–E site compared to the S–F site, and slightly increased in older participants and in participants exposed to more fluoride technologies. GEE (PF) also indicated that progression was slightly more common in the F–E site; more frequent snacking and lower parental educational attainment had modest associations with increased progression in PF surfaces. For the two types of surfaces, GEE models demonstrated that unerupted surfaces were less likely to progress than sound surfaces. No associations were found between reversals and independent variables. Conclusion: Progressions were found to be weakly linked to socio–demographic factors; baseline surface statuses were better predictors of progression. Using the current definitions for disease transitions, F–E communities had more frequent progressions than a S–F community.

Cury, J.A.; Hashizume, L.N.; Del Bel Cury, A.A.; Tabchoury, C.P.M.

doi: 10.1159/000047440pmid: 11275669

The additive effect of baking soda on the anticariogenic effect of fluoride dentifrice is not well established. To evaluate it, a crossover in situ study was done in three phases of 28 days. Volunteers, using acrylic palatal appliances containing four human enamel blocks, two sound (to evaluate demineralization) and two with artificial caries lesions (to evaluate remineralization), took part in this study. During each phase, 10% sucrose solution was dripped (3 times a day) only onto the sound blocks. After 10 min, a slurry of placebo, fluoride (F) or fluoride and baking soda (F+NaHCO₃) dentifrice was dripped onto all enamel blocks. The results showed a higher F concentration in dental plaque formed during treatment with F+NaHCO₃ than placebo (p<0.05), but the difference related to F dentifrice was not significant. The enamel demineralization was lower, and remineralization was greater, after treatment with F+NaHCO₃ than placebo (p<0.05), but the difference related to F dentifrice was not significant. The data suggest that baking soda neither improves nor impairs the effect of F dentifrice on reduction of demineralization and enhancement of remineralization of enamel.

Yamamoto, H.; Iwami, Y.; Unezaki, T.; Tomii, Y.; Ebisu, S.

doi: 10.1159/000047441pmid: 11275670

Class V cavities were prepared in the upper and lower left second premolars from an individual under infiltration anesthesia. The cavities were filled with fluoride– releasing resin (TF). One month later, the teeth were extracted. As a control (in vitro), the upper and lower right second premolars were extracted at the time of the cavity preparation in vivo. Immediately after extraction, class V cavities were prepared and filled with TF, and immersed in normal saline solution for 1 month at 37°C. All four premolars were bisected longitudinally and the fluoride uptake around the cavity wall on the cut surface was measured using an electron probe microanalyzer–wavelength dispersive X–ray method. The fluoride uptake was given in the form of a two–dimensional map. Comparison of the observed values of each corresponding part of the tooth in vivo and in vitro revealed no characteristic differences. The maps were quite analogous as a whole.

Vogel, G.L.; Zhang, Z.; Chow, L.C.; Schumacher, G.E.

doi: 10.1159/000047442pmid: 11275671

Labile reservoirs are important in maintaining ion concentrations in oral fluids, especially after a fluoride dentifrice application, where a persistent increase in fluid fluoride can mitigate or reverse caries progression. In this study, the effect of experimental and conventional fluoride rinses on the in vitro and in vivo water–induced release of fluoride, calcium, phosphate, acetate and hydrogen ions from oral reservoirs was examined. At the start of each experiment, 13 subjects rinsed either with a conventional 228–ppm fluoride NaF rinse, a 228–ppm fluoride controlled–release rinse (CR rinse) or received no rinse. Sixty minutes later upper and lower molar plaque samples and 1–min saliva samples were collected. The subjects then rinsed with deionized water for 1 min, and 7 min later, a second set of samples was collected (in vivo study). Plaque fluid and clarified saliva were then recovered from samples by centrifugation, and the remaining plaque mass was sequentially extracted with water and acid to measure the water–extracted and total whole–plaque fluoride (in vitro study). All the samples were analyzed using microtechniques for pH, free calcium, phosphate, organic acids (plaque fluid) and fluoride (plaque fluid, centrifuged saliva and plaque extracts). Results showed that in vivo water rinsing decreased acetate and phosphate in plaque fluid, and fluoride in plaque fluid and saliva, but had no effect on plaque fluid pH. In vivo water rinsing, however, increased plaque fluid free calcium, apparently due to water–induced loss of calcium–binding ions. Water– or fluoride–rinse–induced changes in plaque fluid concentration were greater at the lower molar site, suggesting that rinse pooling may influence ion distribution. Before the water rinse, plaque fluid, saliva and whole–plaque total fluoride values were 1.7, 2 and 4 times higher after the CR rinse compared to the NaF rinse. Furthermore, the CR rinse deposited approximately 11 times more water–extracted fluoride compared to the NaF rinse, suggesting a ‘more efficient’ precipitation of ‘labile’ or ‘loosely bound fluoride’. The results presented here, and in previous studies, suggest the possibility of formulating effective fluoride dentifrices with a lower fluoride content than is currently in use.

Luke, J.

doi: 10.1159/000047443pmid: 11275672

The purpose was to discover whether fluoride (F) accumulates in the aged human pineal gland. The aims were to determine (a) F–concentrations of the pineal gland (wet), corresponding muscle (wet) and bone (ash); (b) calcium–concentration of the pineal. Pineal, muscle and bone were dissected from 11 aged cadavers and assayed for F using the HMDS–facilitated diffusion, F–ion–specific electrode method. Pineal calcium was determined using atomic absorption spectroscopy. Pineal and muscle contained 297±257 and 0.5±0.4 mg F/kg wet weight, respectively; bone contained 2,037±1,095 mg F/kg ash weight. The pineal contained 16,000±11,070 mg Ca/kg wet weight. There was a positive correlation between pineal F and pineal Ca (r = 0.73, p<0.02) but no correlation between pineal F and bone F. By old age, the pineal gland has readily accumulated F and its F/Ca ratio is higher than bone.

Mäkinen, K.K.; Isotupa, K.P.; Kivilompolo, T.; Mäkinen, P.L.; Toivanen, J.; Söderling, E.

doi: 10.1159/000047444pmid: 11275673

The effect of 2–month usage of saliva–stimulating pastils containing either erythritol or xylitol was studied in a cohort of 30 subjects assigned to the respective polyol groups (n = 15). The daily consumption level of both polyols was 5.2 g, used in 5 daily chewing episodes. The mean weight of total plaque mass (collectable during a standard period of 3 min from all available tooth surfaces) was reduced significantly in the xylitol–group, while no such effect was observed in the erythritol–group. This reduction in plaque mass was accompanied by a significant reduction in the turbidity readings (A₆₆₀) of aqueous plaque suspensions; no such effect was observed in the erythritol–group. However, plaque protein levels did not differ between baseline and endpoint in either polyol group. The plaque and salivary levels of Streptococcus mutans and plaque levels of total streptococci were reduced significantly in the xylitol–group, while no such effect was detected in the erythritol–group. However, either polyol regimen had no effect on plaque levels of S. sobrinus. The results suggest that systematic use of xylitol–containing saliva stimulants may be more effective in controlling some oral–hygiene–related and caries–associated parameters than similar use of erythritol–containing products. The results also speak for a special relationship between xylitol and S. mutans. However, owing to the great potential of erythritol as a caries–reducing agent – based on the tetritol nature of erythritol – the present laboratory results should be considered preliminary and subject to verifying clinical studies.

Robinson, C.; Brookes, S.J.; Kirkham, J.; Wood, S.R.; Shore, R.C.

doi: 10.1159/000047445pmid: 11275674

Instead of removing the porous carious tissue at a relatively late stage in the disease process, attempts have been made to ‘fill’ the microporosities of lesions at a much earlier stage of lesion development. This would not only reduce the porosity and therefore access of acid and egress of dissolved material, but also afford some mechanical support to the tissue and perhaps inhibit further attack. Successful infiltration of materials into lesions has been demonstrated previously using resorcinol–formaldehyde which, however, was clinically unacceptable. The advent of dental adhesives with potentially suitable properties has prompted a re–examination of this concept. Artificial lesions of enamel were generated in extracted human teeth using acidified gels. A range of currently available adhesive materials was then used to infiltrate the porosities. The extent of occlusion of the lesion porosities was determined both qualitatively using light microscopy and quantitatively using a chloronaphthalene imbibition technique. The effect of such treatment upon subsequent exposure to acid gels was also investigated. Results showed that up to 60% of the lesion pore volume had been occluded following infiltration with some of the materials and that this treatment was capable of reducing further acid demineralization. The development of such treatment strategies could offer potential noninvasive means of treating early enamel lesions.

Hannig, M.; Balz, M.

doi: 10.1159/000047446pmid: 11275675

The purpose of this study was to investigate the protective effect and ultrastructure of salivary pellicles formed in vivo near the orifices of the ducts of parotid and submandibular/sublingual salivary glands. Pellicles were formed by exposing bovine enamel slabs to the oral environment at the buccal aspect of the upper first molars and at the lingual aspect of the lower incisors in 3 subjects over periods of 24 h. Enamel specimens with and without 24–hour pellicles were immersed in citric acid (0.1 and 1%) for periods ranging from 30 s to 5 min, and processed for measurement of surface microhardness (SMH) and transmission electron microscopy (TEM). In comparison to uncovered enamel specimen significantly less decrease in SMH due to acid exposure was observed in pellicle–coated enamel specimens. Pellicles formed at the buccal aspect of the upper molars were less effective in protecting the enamel against acid–induced softening as compared to pellicles formed at the lingual aspect of the lower incisors only after 5 min exposure in 1% citric acid. TEM analysis showed that pellicle layers were dissolved continously due to acid exposure. However, even after 5 min exposure to 1% citric acid, a residual pellicle layer could be detected on the enamel surface. In conclusion, site–dependent differences of buccally and lingually in vivo formed 24–hour pellicles have minor importance concerning the pellicle–induced protection of the enamel surface against erosive changes.