Effects of silver diamine fluoride on demineralization protection after a secondary acid challenge

Abstract Objective This investigation describes the effects of 5% sodium fluoride varnish and 38% silver diamine fluoride on demineralization protection of human enamel lesions of three different severities after a secondary acid challenge. Study design Specimens underwent color and enamel surface microhardness change measurements after demineralization and treatment events. Transverse microradiography was conducted following the secondary demineralization. Results After treatments, enamel surface microhardness change showed that 24-hour lesions treated with fluoride varnish had less rehardening than 24-hour lesions treated with silver diamine fluoride (p<0.05), whereas 144-hour lesions from both treatment groups showed a beneficial decrease in surface microhardness change that was markedly better in samples treated with silver diamine fluoride (p<0.05). After the secondary demineralization, 24- and 144-hour lesions treated with silver diamine fluoride showed a sustained beneficial decrease in enamel surface microhardness change when compared to fluoride varnish-treated samples of the corresponding lesion severity (p<0.05). Transverse microradiography showed no difference between fluoride varnish- and silver diamine fluoride-treated samples of any corresponding lesion severity, indicating that remineralization in both fluoride varnish- and silver diamine fluoride-treated samples was proportional to each other after a secondary acid challenge. Conclusions Using silver diamine fluoride may have comparable benefits to fluoride varnish in mineral loss prevention.

Susceptibility of fluorotic enamel to dental erosion-abrasion

Abstract Dental hard tissue conditions can be of pre- or post-eruptive nature, such as enamel fluorosis and erosive tooth wear (ETW), respectively. Dental enamel fluorosis is caused by the chronic and excessive intake of fluoride during enamel development, leading to increased fluoride concentration and increased porosity. ETW has become a common clinical condition and often impairs dental function and aesthetics. This in vitro study tested the hypothesis that fluorotic enamel presents different susceptibility to dental erosion-abrasion. It consisted of a 3×3×2 factorial design, considering a) fluorosis severity: sound (TF0), mild (TF1-2), moderate (TF3-4); b) abrasive challenge: low, medium, and high; and c) erosive challenge: yes or no. A total of 144 human teeth were selected according to the three fluorosis severity levels (n=48), and subdivided into six groups (n = 8) generated by the association of the different erosive and abrasive challenges. Enamel blocks (4×4 mm) were prepared from each tooth and their natural enamel surfaces subjected to an erosion-abrasion cycling model. After cycling, the depth of the lesions in enamel was assessed by profilometry. ANOVA showed that the three-way and two-way interactions among the factors were not significant (p > 0.20). Enamel fluorosis level (p=0.638) and abrasion level (p = 0.390) had no significant effect on lesion depth. Acid exposure caused significantly more enamel surface loss than water (p < 0.001). Considering the limitations of this in vitro study, fluorosis did not affect the susceptibility of enamel to dental erosion-abrasion.

Longitudinal assessment of dental erosion-abrasion by cross-polarization optical coherence tomography in vitro

Abstract: This study tested a novel in vitro dental erosion-abrasion model and the performance of cross-polarization optical coherence tomography (CP-OCT) in longitudinally monitoring the simulated lesions. Thirty human enamel specimens were prepared and randomized to receive three dental erosion-abrasion (EA) protocols: severe (s-EA, lemon juice/pH:2.5/4.25%w/v citric acid), moderate (m-EA, grapefruit juice/pH:3.5/1.03%w/v citric acid) and no-EA (water, control). EA challenge was performed by exposing the specimens to acidic solutions 4x/day and to brushing 2x/day with 1:3 fluoridated toothpaste slurry, for 14 days. Enamel thickness measurements were obtained using CP-OCT at baseline (D0), 7 (D7) and 14 days (D14) and micro-computed tomography (micro-CT) at D14. Enamel surface loss was measured with both CP-OCT and optical profilometry at D0, D7 and D14. Data was analyzed with repeated-measures ANOVA and Pearson's correlation (r) (α = 0.05). CP-OCT enamel thickness decreased over time in the s-EA group (D0 >D7 > D14, p < 0.001) and m-EA group (D0 > D14, p = 0.019) but did not change in the no-EA group (p = 0.30). Overall, CP-OCT and micro-CT results at D14 correlated moderately (r = 0.73). CP-OCT surface loss was highest for s-EA (p <0.001) but did not differ between moderate and no-EA (p = 0.25). Enamel surface loss with profilometry increased with severity (no-EA>m-EA>s-EA, p < 0.001). D14 surface loss was higher than D7 for both methods except for the no-EA group with profilometry. CP-OCT and profilometry had moderate overall correlation (r = 0.70). Our results revealed that the currently proposed in vitro dental erosion-abrasion model is valid and could simulate lesions of different severities over time. CP-OCT was a suitable method for monitoring the EA lesions.

Caries lesion remineralization with fluoride toothpastes and chlorhexidine - effects of application timing and toothpaste surfactant

Abstract Habitual toothbrushing with fluoridated toothpaste followed by rinsing with antibacterial mouthwashes is a method to maintain good oral hygiene and to diminish the occurrence and severity of dental caries and periodontal disease. However, our understanding of how antimicrobial agents in mouthwashes affect fluoride-mediated caries lesion remineralization is still poor. Objective: The objectives of this in vitro study were a) to determine the effects of the waiting period of chlorhexidine (CHX) rinsing after fluoride toothpaste use and b) to further determine the effect of the type of toothpaste surfactant [sodium dodecyl sulfate (SDS) or cocamidopropyl betaine (CAPB)] on caries lesion remineralization associated with CHX rinsing. Material and Methods: Caries lesions were formed in bovine enamel specimens and assigned to 10 treatment groups (n=18) based on Vickers surface microhardness (VHN). Lesions were then pH-cycled for 10 days with daily regimen comprised of twice daily toothpaste slurry treatments (1150 ppm fluoride, with SDS or CAPB), followed by CHX solution treatments [0, 15, 30 or 60 minutes following slurry treatment or no CHX treatment (negative control)]. VHN was measured again and the extent of lesion remineralization calculated (∆VHN). Results: ∆VHN with SDS-toothpaste was significantly lower than with CAPB-toothpaste, indicating more remineralization for the CAPB-toothpaste. ∆VHN with 0-minute waiting time was significantly lower than with 30-minute waiting time and with negative control. Conclusions: The absence of CHX as an adjunct to fluoride toothpastes led to greater remineralization of enamel lesions compared with the immediate use of CHX treatment for both SDS- and CAPB-toothpastes. CAPB-toothpastes indicated significantly greater remineralization than SDS-toothpastes, and can be suggested for patients at high risk of caries. A 30-minute waiting time for CHX treatment is recommended after brushing.

Quantitative light-induced fluorescence (QLF) in relation to other technologies and conventional methods for detecting occlusal caries in permanent teeth

Aim: The aim of this in vitro study was to compare the reproducibility and accuracy of quantitative light-induced fluorescence (QLF) in relation to other technologies and conventional methods fordetecting occlusal carious lesions. Methods: Ninety-six extracted permanent molar teeth wereselected. Three examiners carried out examinations using Visual examination (VI), bitewing radiographs (RX), QLF, electrical conductance measurement (ECM), and DIAGNOdent. Twenty five percent of the teeth were re-examined for repeatability. Stereomicroscopic examination was used as the gold standard. Results: Intra- and inter-examiner agreement ranged from 0.43 to 0.89. Areas under ROC curves were 0.82, 0.54, 0.84, 0.79 and 0.88, respectively, for VI, RX,QLF, ECM and DIAGNOdent examinations, with RX significantly lower than the other methods. No significant statistical difference was found when comparing the areas under ROC curve of visual inspection and QLF. Conclusions: Although QLF and other technologies for early caries detection may offer some advantages, this study did not find significant improvement in occlusal caries detection when compared to visual examination.

Evaluation of three radiographic methods for detecting occlusal caries lesions

Aim: To compare, in vitro, the performance of three radiographic methods for the detection of occlusal caries in permanent teeth. Methods: A total of 96 extracted molars with no apparent occlusal cavitation were selected, they were photographed and radiographed under standardized conditions using conventional E-plus films and two digital systems, CDR and Sidexis. Two examiners analyzed all films and images, recording the presence and lesion depth. One quarter of the teeth were re-examined for intra- and interexaminer agreements. The teeth were subsequently bisected and examined under a stereomicroscope. The intra and interexaminer agreements and the diagnostic performance (sensitivity, specificity, accuracy and the area under receiver operating characteristic, ROC curve) of each method were evaluated. Results: Out of 96 occlusal surfaces, 41 were sound, 31 had lesions in enamel, and 24 had dentin lesions. Weighted Kappa values for intraexaminer agreement varied widely, depending on both the observer and method. The interexaminer agreement was higher for the digital images than for the conventional films. The area under the ROC curve for enamel and dentin caries (at D1 diagnostic threshold) was 0.55 for films, 0.60 for Schick and 0.54 for Sirona, which were not significantly different from each other. Conclusions: Digital images presented better results of interexaminer agreement; however, no additional effect in the diagnostic performance could be observed in comparison to conventional films.

Detecção de cáries oclusais in vitro / In vitro detection occlusal cavities

O objetivo deste estudo foi determinar a confiabilidade e a validade de dois métodos de fluorescência DIAGNOdent (KaVo) e QLF/clin (QLF-Inspektor Research Systems) e exame visual(V) 1 para detectar cáries oclusais incipientes em pré-molares. Noventa e nove pré- molares foram selecionados e examinados através dos três métodos. Dois examinadores realizaram V e a interpretação do DIAGNodent, enquanto apenas o primeiro autor examinou os dentes com QLF. O segundo autor treinou o primeiro autor a usar o critério visual, enquanto o primeiro autor treinou o segundo a usar o DIAGNOdent. O primeiro autor era bem treinado em usar o QLF. Como padrão (gold standard), usou-se um critério histológico com cinco categorias representando a profundidade das lesões em cortes histológicos(H). A intraconfibilalidade de V e do DIAGNOde), enquanto a interconfibialidade foi substancial. A intraconfibialidade do QLF foi menor (ICC=0,51). A validade para os três métodos foi moderada quando o método H foi usado. As lesões avaliadas por V e DIAGNOdent eram histologicamente mais profundas do que o esperado, enquanto as lesões avaliadas por QLF eram menos profundas do que o esperado. Tanto o DIAGNOdent quanto o QLF foram métodos muito pobres para expressar o tamanho da área da lesão na seção correspondente. Conclui-se que a confiabiblidade do critério visual (V) e DIAGNOdent foi quase perfeita, mas a precisão foi pobre. Isto indica que novos sistemas histológicos devem ser desenvolvidos.