Richard J. Wierichs

Re- and Demineralization Characteristics of Enamel Depending on Baseline Mineral Loss and Lesion Depth in situ

Objectives: The aim of this double-blinded, randomized, cross-over in situ study was to evaluate the re- and demineralization characteristics of sound enamel as well as lowly and highly demineralized caries-like enamel lesions after the application of different fluoride compounds. Methods: In each of three experimental legs of 4 weeks, 21 participants wore intraoral mandibular appliances containing 4 bovine enamel specimens (2 lowly and 2 highly demineralized). Each specimen included one sound enamel and either one lowly demineralized (7 days, pH 4.95) or one highly demineralized (21 days, pH 4.95) lesion, and was positioned 1 mm below the acrylic under a plastic mesh. The three randomly allocated treatments (application only) included the following dentifrices: (1) 1,100 ppm F as NaF, (2) 1,100 ppm F as SnF2 and (3) 0 ppm F (fluoride-free) as negative control. Differences in integrated mineral loss (ΔΔZ) and lesion depth (ΔLD) were calculated between values before and after the in situ period using transversal microradiography. Results: Of the 21 participants, 6 did not complete the study and 2 were excluded due to protocol violation. Irrespectively of the treatment, higher baseline mineral loss and lesion depth led to a less pronounced change in mineral loss and lesion depth. Except for ΔΔZ of the dentifrice with 0 ppm F, sound surfaces showed significantly higher ΔΔZ and ΔLD values compared with lowly and highly demineralized lesions (p < 0.05, t test). Conclusion: Re- and demineralization characteristics of enamel depended directly on baseline mineral loss and lesion depth. Treatment groups should therefore be well balanced with respect to baseline mineral loss and lesion depth.

Caries-Preventive Effect of NaF, NaF plus TCP, NaF plus CPP-ACP, and SDF Varnishes on Sound Dentin and Artificial Dentin Caries in vitro

The aim of this study was to compare the caries-preventive effect of different fluoride varnishes on sound dentin as well as on artificial dentin caries-like lesions. Bovine dentin specimens (n = 220) with one sound surface (ST) and one artificial caries lesion (DT) were prepared and randomly allocated to 11 groups. The interventions before pH cycling were as follows: application of a varnish containing NaF (22,600 ppm F^-; Duraphat [NaF₀/NaF₁]), NaF plus tricalcium phosphate (22,600 ppm F^-; Clinpro White Varnish Mint [TCP₀/TCP₁]), NaF plus casein phosphopeptide-stabilized amorphous calcium phosphate complexes (CPP-ACP; 22,600 ppm F^-; MI Varnish [CPP₀/CPP₁]), or silver diamine fluoride (SDF; 35,400 ppm F^-; Cariestop 30% [SDF₀/SDF₁]) and no intervention (N_NB/N₀/N₁). During pH cycling (14 days, 6 × 120 min demineralization/day) half of the specimens in each group were brushed (10 s; 2 times/day) with either fluoride-free (“0”; e.g., TCP₀) or 1,100 ppm F^- (“1”; e.g., TCP₁) dentifrice slurry. In another subgroup, the specimens were pH cycled but not brushed (N_NB). Differences in integrated mineral loss (ΔΔZ), lesion depth (ΔLD), and colorimetric values (ΔΔE) were calculated between the values after initial demineralization and those after pH cycling, using transversal microradiography and photographic images. After pH cycling, no discoloration could be observed. Furthermore, N_NB, N₀, and N₁ showed significantly increased ΔZ_DT/LD_DT and ΔZ_ST/LD_ST values, indicating further demineralization. In contrast, CPP₀, CPP₁, SDF₀, and SDF₁ showed significantly decreased ΔZ_DT/LD_DT values, indicating remineralization (p ≤ 0.004; paired t test). CPP₀, CPP₁, SDF₀, and SDF₁ showed significantly higher changes in ΔΔZ_DT/ΔLD_DT and ΔΔZ_ST/ΔLD_ST than N_NB, N₀, and N₁ (p < 0.001; Bonferroni post hoc test). In conclusion, under the conditions chosen, all fluoride varnishes prevented further demineralization. However, only NaF plus CPP-ACP and SDF could remineralize artificial dentin caries-like lesions under net-demineralizing conditions, thereby indicating that NaF plus CPP-ACP and SDF may be helpful to high-caries-risk patients.

Effects of Self-Assembling Peptide P11-4, Fluorides, and Caries Infiltration on Artificial Enamel Caries Lesions in vitro

The application of a self-assembling peptide on noncavitated caries lesions is supposed to be a feasible approach to facilitate remineralization and mask their unfavorable appearance. However, demineralizing conditions are common in the oral environment, so the aim of this pH-cycling study was to compare recommended and novel treatment methods regarding their ability to hamper demineralization and as a consequence mask artificial enamel caries lesions. Artificial caries lesions were prepared in bovine enamel and randomly allocated to 11 groups (n = 22). Treatments before pH-cycling were as follows: the application of a self-assembling peptide (Curodont™ Repair [C]), a low-viscosity resin (Icon® [I]), 2 fluoride solutions (10,000 ppm F^-: Elmex fluid [E] and 43,350 ppm F^-: Tiefenfluorid® [T]), and no intervention (N). During pH-cycling (28 days, 6 × 60 min demineralization/day) half of the specimens in each group were brushed (10 s; 2 ×/day) with either fluoride-free (named e.g., C₀) or NaF (1,100 ppm F^-; e.g., C₁) dentifrice slurry. In another subgroup specimens were pH-cycled but not brushed (N_NB). Differences in integrated mineral loss (ΔΔZ), lesion depth (ΔLD), and colorimetric values (ΔΔE) were calculated between values after pre-demineralization, surface treatment, and pH-cycling. Specimens of C₀, C₁, N_NB, N₀, N₁, T₀, and E₀ showed significantly increased ΔZ and LD values after pH-cycling (p ≤ 0.003; paired t test). C₀, C₁, N_NB, and N₀ showed significantly higher changes in ΔΔZ than E₁, I₀, I₁, and T₁ (p < 0.001; ANOVA). Significantly reduced colorimetric values could only be observed for I₁, I₀, E₁, and E₀ after treatment and after pH-cycling (p ≤ 0.027; paired t test). In conclusion, under the conditions chosen only the application of a low-viscosity resin could mask caries lesions significantly, whereas self-assembling peptides could neither inhibit lesion progression nor mask the lesions considerably.

Risk factors for failure of class V restorations of carious cervical lesions in general dental practices

OBJECTIVES The aim of this retrospective, non-interventional, multi-center, practice-based study was to analyze factors influencing the survival of restorative treatments of one- and two-surface active cervical (root) caries lesions (CCLs). METHODS Records from patients who visited five private practices regularly were searched for the presence of active one- and two-surface CCLs. Data from 1167 patients with 2070 CCLs being detected at least 6 months before the last recall visit were recorded. Kaplan-Meier-analyses were used to analyze time-to-failure. Cox proportional hazards models were used to evaluate the association between clinical factors and time until failure. RESULTS Within 120 months [mean (SD) follow-up period:50 (40) months] 219 failures could be observed. Median survival time was 120 months. The AFR was 1.82% for one-surface restorations (CCL1) and 3.25% for two-surface restorations (CCL2). In multivariate Cox regression two-surface cervical restorations showed 1.75 times higher failure rates than one-surface cervical restoration. Furthermore, CCL being checked up more than twice a year showed significantly higher failure rates than restorations being checked up less than twice a year (p < 0.001). CONCLUSION Low failure rates could be found for restorative treatment strategies of one- as well as for two-surface CCLs. CLINICAL SIGNIFICANCE Restorative treatment of CCLs is a viable way to manage one-surface CCLs. However, the proximal extension of the CCL significantly shortens the longevity of the restoration. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00012510).

Acknowledgement to Reviewers 2014

Adair, P. Adams, G. Aleksejuniene, J. Alves, L. Amaechi, B. Anderson, P. Armfield, J. Arnold, W. Arthur, R. Ashley, P. Bader, J. Baelum, V. Baumann, T. Bertacci, A. Bhawal, U. Bjorndal, L. Bottenberg, P. Boushell, L. Bowen, W. Bradshaw, D. Braga, M. Breschi, L. Brighenti, F. Broadbent, J. Bronkhorst, E. Buchalla, W. Burnside, G. Burrow, M. Campus, G. Carey, C. Carpenter, G. Carvalho, J. Caufield, P. Charone, S. Chow, L.C. Clarkson, B. Creeth, J. Darvell, B. Dashper, S. Davies, J.