Sebastian Paris

Resin Infiltration of Natural Caries Lesions

Infiltration of non-cavitated caries lesions with light-curing resins could lead to an arrest of lesion progression. The aim of this study was to evaluate the penetration of a conventional adhesive into natural enamel caries after pre-treatment with two different etching gels in vitro. Extracted human molars and premolars showing proximal white-spot lesions were cut across the lesions perpendicular to the surface. Corresponding lesion halves were etched for 120 sec with either 37% phosphoric acid gel (H3PO4) or 15% hydrochloric acid gel (HCl), and subsequently infiltrated with an adhesive. Specimens were observed by confocal microscopy. Mean penetration depths (SD) in the HCl group [58 (37) μm] were significantly increased compared with those of the H3PO4 group [18 (11) μm] (p < 0.001; Wilcoxon). It can be concluded that etching with 15% hydrochloric acid gel is more suitable than 37% phosphoric acid gel as a pre-treatment for caries lesions intended to be infiltrated.

Socioeconomic Inequality and Caries A Systematic Review and Meta-Analysis

Dental caries is the most prevalent disease worldwide, with the majority of caries lesions being concentrated in few, often disadvantaged social groups. We aimed to systematically assess current evidence for the association between socioeconomic position (SEP) and caries. We included studies investigating the association between social position (determined by own or parental educational or occupational background, or income) and caries prevalence, experience, or incidence. Risk of bias was assessed using the Newcastle-Ottawa Scale for observational studies. Reported differences between the lowest and highest SEP were assessed and data not missing at random imputed. Random-effects inverse-generic meta-analyses were performed, and subgroup and meta-regression analyses were used to control for possible confounding. Publication bias was assessed via funnel plot analysis and the Egger test. From 5539 screened records, 155 studies with mostly low or moderate quality evaluating a total of 329,798 individuals were included. Studies used various designs, SEP measures, and outcome parameters. Eighty-three studies found at least one measure of caries to be significantly higher in low-SEP compared with high-SEP individuals, while only 3 studies found the opposite. The odds of having any caries lesions or caries experience (decayed missing filled teeth [DMFT]/dmft > 0) were significantly greater in those with low own or parental educational or occupational background or income (between odds ratio [95% confidence interval] = 1.21 [1.03–1.41] and 1.48 [1.34–1.63]. The association between low educational background and having DMFT/dmft > 0 was significantly increased in highly developed countries (R2 = 1.32 [0.53–2.13]. Publication bias was present but did not significantly affect our estimates. Due to risk of bias in included studies, the available evidence was graded as low or very low. Low SEP is associated with a higher risk of having caries lesions or experience. This association might be stronger in developed countries. Established diagnostic and treatment concepts might not account for the unequal distribution of caries (registered with PROSPERO [CRD42013005947]).

Resin Infiltration of Caries Lesions an Efficacy Randomized Trial

Resin infiltration is an innovative approach to arrest progression of caries lesions. The aim of this randomized split-mouth placebo-controlled clinical trial was to assess whether resin infiltration of proximal lesions is more effective than non-operative measures alone with respect to the inhibition of caries progression. In 22 young adults, 29 pairs of interproximal lesions with radiological extension into the inner half of enamel or the outer third of dentin were randomly allocated to two treatment groups. In the test group, lesions were infiltrated (Icon, pre-product; DMG). A placebo treatment was performed in the control group. All participants received instructions for diet, flossing, and fluoridation. The primary outcome after 18 months was radiographic lesion progression (assessed by digital subtraction radiography). No unwanted effects could be observed. In the effect group, 2/27 lesions (7%) and in the control group 10/27 lesions (37%) showed progression (p = 0.021; McNemar). Infiltration of interproximal caries lesions is efficacious in reducing lesion progression.

Morphological and bond strength evaluation of different resin cements to root dentin

This study correlated the morphological characteristics with the bond strengths of various resin cements used for bonding fiber posts to root canal dentin. Fifty glass-fiber posts (FRC Postec Plus) were luted into the root canals of extracted human anterior teeth using five resin cements (n = 10): Panavia F 2.0, PermaFlo DC, Variolink II, RelyX Unicem, and Clearfil Core. Before insertion of the post, the adhesive systems were labeled with fluorescein and the resin cement was labeled with rhodamine isothiocyanate. The roots were sectioned into three slices (of 2 mm thickness), and each slice was analyzed using confocal laser scanning microscopy in dual fluorescence mode to determine hybrid layer thickness, the number of resin tags, and the number of broken tags. Bond strengths were measured using a micro push-out test. Bond strengths to root canal dentin, as well as the morphological characteristics, were significantly affected by the materials. However, these factors did not correlate. The self-adhesive resin cement, which showed the formation of a hybrid layer and resin tags only sporadically, had the highest bond strengths. These results indicate that chemical interactions between the adhesive cement and hydroxyapatite may be more crucial for root dentin bonding than the ability of the same material to hybridize dentin.

Improved Resin Infiltration of Natural Caries Lesions

In artificial lesions, improved penetration and the caries-inhibiting properties of infiltrating resins could be observed with increasing penetration coefficients (PCs). The aim of the present study was to compare the penetration abilities of an experimental ‘infiltrant’ into natural lesions with those of an adhesive in vitro. Extracted human molars and premolars showing proximal white spots were cut across the lesions perpendicular to the surface. Corresponding lesion halves were etched for 120 sec with 15% hydrochloric acid gel and were subsequently treated with either an adhesive (PC: 31 cm/sec) or an infiltrant (PC: 273 cm/sec). Specimens were observed by confocal microscopy and transverse microradiography. Penetration depths of the adhesive were significantly lower compared with those of the infiltrant (p < 0.001; Wilcoxon). It can be concluded that resins with higher PCs (infiltrants) show superior ability to penetrate natural lesions compared with resins with lower PCs.

Surface Layer Erosion of Natural Caries Lesions with Phosphoric and Hydrochloric Acid Gels in Preparation for Resin Infiltration

The infiltration of proximal enamel lesions with low-viscosity light curing resins could be a viable approach to stop lesion progression. However, penetration of sealant might be hampered by the comparatively highly mineralized surface layers of natural lesions. Therefore, the aim of this study was to compare the efficacy of three different etching gels in removing the surface layer in various etching times. Extracted human molars and premolars showing proximal white spot lesions were cut across the demineralized areas. Ninety-six lesions expected from visual examination to be confined to the outer enamel (C1) were selected. The cut surface and half of each lesion were varnished, thus serving as control. Subsequently, the lesions were etched with either phosphoric (37%) or hydrochloric (5 or 15%) acid gel for 30–120 s (n = 8/group). Specimens were examined using confocal microscopy and transversal microradiography. Surface layer reduction was significantly increased in lesions etched with 15% HCl gel for 90 and 120 s compared to those etched with H3PO4 gel for 30–120 s (p < 0.05). No significant differences regarding the depths of erosion in the lesions compared to sound enamel could be observed (p > 0.05). An effective reduction in the surface layer of natural enamel caries can be achieved by etching with 15% hydrochloric acid gel for 90–120 s.

Incomplete Caries Removal A Systematic Review and Meta-analysis

Increasing numbers of clinical trials have demonstrated the benefits of incomplete caries removal, in particular in the treatment of deep caries. This study systematically reviewed randomized controlled trials investigating one- or two-step incomplete compared with complete caries removal. Studies treating primary and permanent teeth with primary caries lesions requiring a restoration were analyzed. The following primary and secondary outcomes were investigated: risk of pulpal exposure, post-operative pulpal symptoms, overall failure, and caries progression. Electronic databases were screened for studies from 1967 to 2012. Cross-referencing was used to identify further articles. Odds ratios (OR) as effect estimates were calculated in a random-effects model. From 364 screened articles, 10 studies representing 1,257 patients were included. Meta-analysis showed risk reduction for both pulpal exposure (OR [95% CI] 0.31 [0.19-0.49]) and pulpal symptoms (OR 0.58 [0.31-1.10]) for teeth treated with one- or two-step incomplete excavation. Risk of failure seemed to be similar for both complete and incomplete excavation, but data for this outcome were of limited quality and inconclusive (OR 0.97 [0.64-1.46]). Based on reviewed studies, incomplete caries removal seems advantageous compared with complete excavation, especially in proximity to the pulp. However, evidence levels are currently insufficient for definitive conclusions because of high risk of bias within studies.

Progression of Artificial Enamel Caries Lesions after Infiltration with Experimental Light Curing Resins

The arrest of enamel caries lesions by infiltration with low-viscosity light curing resins might be a promising approach of microinvasive dentistry. However, no materials optimized for rapid lesion infiltration (‘infiltrants’) are commercially available today. The penetration coefficient (PC) of experimental resins has been shown to correlate with penetration speed and, therefore, might be an important feature of infiltrants. The aim of the present study was to evaluate the influence of PC and composition of experimental infiltrants on the progression of enamel lesions in a demineralizing environment. Artificial enamel lesions were prepared in a demineralization solution for 50 days and infiltrated with either one of twelve experimental infiltrants or a commercially available adhesive for 10, 22, and 40 s, respectively. Specimens were cut perpendicularly to the surface and one half of each specimen was exposed to a demineralizing solution for another 50 days, whereas the other half was used as baseline control. Lesion progression was analyzed using confocal microscopy (CLSM) and transversal microradiography (TMR). The square root of the product of PC and application time was negatively correlated with progression of lesion depth (CLSM: r = –0.741; TMR: r = –0.450). Therefore, infiltrants should preferably have high PCs to facilitate inhibition of lesion progression efficiently.

Inhibition of caries progression by resin infiltration in situ.

The infiltration of caries lesions with low-viscosity light-curing resins (infiltrants) has been shown to inhibit further demineralization in vitro. The aim of the present study was to assess the efficacy of resin infiltration in preventing lesion progression in situ. In each of 104 bovine enamel specimens, 2 artificial enamel caries lesions were created. The specimens were randomly allocated to 2 groups: in the test group, 1 of the lesions was etched for 5 s (37% H3PO4) and subsequently infiltrated twice with a preproduct infiltrant, each time for 60 s. As a positive control, 1 lesion was superficially sealed with a fissure sealant. The second lesion in each specimen served as an untreated control. The specimens were inserted into intraoral appliances and worn by 11 volunteers in the mandibular buccal sulcus for 100 days. Plaque accumulation was promoted by a mesh, and the appliances were stored in 10% sucrose solution (2 × 30 min/day). The specimens were analyzed using transversal microradiography and wavelength-independent microradiography. The specimens of 2 participants were excluded from analysis. The baseline integrated mineral losses (transversal microradiography values; mean ± SD: 2474 ± 549 vol% × µm) and lesion depths (98 ± 20 µm) did not differ significantly between the various groups (p > 0.05; paired t test). After the in situ phase, the infiltrated and positive control lesions showed significantly less progression compared to the untreated controls (p < 0.05). It can be concluded that resin infiltration is efficacious in preventing further demineralization of artificial enamel caries lesions under cariogenic conditions in situ.

Randomized controlled clinical trial on proximal caries infiltration: three-year follow-up

We report the 3-year efficacy of resin infiltration (Icon, pre-product; DMG, Hamburg) to arrest progression of proximal non-cavitated caries lesions as compared with placebo treatment. In 22 young adults, 29 lesion pairs with radiographic extensions into the inner half of enamel up to the outer third of dentin were included (split-mouth design). All subjects received risk-related instructions for diet, flossing and fluoridation. No unwanted effects could be observed. Radiographically 1/26 test lesions (4%) and 11/26 control lesions (42%) had progressed (p = 0.002, McNemar). After 3-year follow-up, infiltration of proximal caries lesions can be said to be efficacious to reduce lesion progression.