Distribution of initial caries lesions in relation to fixed orthodontic therapy. A systematic review and meta-analysis.

BACKGROUND: Initial caries lesion (ICLs) adjacent to orthodontic brackets are the most common side effect of orthodontic treatment with fixed appliances. The reported prevalence is uncertain and varies considerably across studies, from 27% to 97%. OBJECTIVES: This paper was designed to evaluate and synthesize the available evidence on the prevalence and incidence rates of ICLs in relation to orthodontic treatment. Selection criteria: The review (Prospero protocol CRD42023412952) included randomized and non-randomized clinical trials of interventions, cohort studies, and cross-sectional studies, published after 1990 on the prevalence or incidence of ICLs during or after orthodontic treatment with fixed appliances. Search methods: Pubmed, Scopus, and Embase databases were searched from 1990 until 01 May 2023. The risk of bias assessment was performed with RoB 2 and ROBINS-I tool and the Joanna Briggs Institute Critical Appraisal Checklist. Data collection and analysis: The proportion of individuals with ICLs, reported as the number/percentage of individuals/teeth with ICLs or mean number of ICLs per subject, were used to synthesize results. RESULTS: The search yielded a total of 468 papers; 21 studies were included in the systematic review, 2 of which were not included in the meta-analysis. The prevalence rate [95%CI] of ICLs was 0.57% [0.48; 0.65] in 1448 patients, 0.22% [0.14; 0.33] in 11583 teeth, with a mean number of lesions equal to 2.24 [1.79; 2.70] in 484 patients evaluated. The incidence rate of new carious lesions developed during orthodontic treatment was 0.48% [0.33; 0.63] in 533 patients, 0.15% [0.08; 0.26] in 1890 teeth with a mean number of ICLs equal to 2.29 [1.12; 3.46] in 208 patients evaluated. LIMITATIONS: Although the high number of included studies and the overall good quality, there was a significant heterogeneity in the collected data. CONCLUSION: The prevalence and incidence rates of ICLs in subjects undergoing orthodontic treatment are quite high and raise some concerns in terms of risk assessment of orthodontic treatment. ICLs represent an alarming challenge for both patients and professionals. Effective caries prevention strategies during treatment need to be considered and implemented where appropriate.

Correlation of quantitative light-induced fluorescence and qualitative visual rating in infiltrated post-orthodontic white spot lesions.

OBJECTIVES: The aim of this prospective, clinical single-centre study was to evaluate the masking efficacy of post-orthodontic resin infiltration after 12-month follow-up and correlate quantitative and qualitative outcome measures. METHODS: Patients with completed fixed orthodontic treatment and the presence of one or more vestibular active non-cavitated white spot lesion/s (WSL) [ICDAS 1 or 2 (International Caries Detection and Assessment System)] were provided with resin infiltration 3-12 months after bracket removal. All patients (n = 31) participating before (t0) intervention were invited again and examined after 12 months (t2). Enamel demineralization was scored using quantitative light-induced fluorescence [QLF (DeltaF[flourescence], DeltaQ[lesion volume], White Spot Area)] and qualitative visual rating [11-point Likert-scale from 0 (no lesions visible on any tooth) to 10 (all teeth affected on the entire vestibular surface)]. RESULTS: In 17 patients (7 female and 10 male) 112 WSL (ICDAS 1: n = 1; ICDAS 2: n = 111) in 112 teeth were (re)examined. Before treatment (t0) a significant, weak (DeltaF), and moderate (DeltaQ, White Spot Area) correlation was observed between the quantitative and the qualitative rating (P < 0.002) [median DeltaF: -7.31 (-10.4/-6.58)%; DeltaQ:-2.25 (-10.8/-0.41)% mm2; White Spot Area: 0.34 (0.05/1.16) mm2; visual rating:3.7 ± 1.2]. Resin infiltration led to significantly increased fluorescence and decreased visual scores (P < 0.001) 7 days (t1) and 12 months (t2) after treatment. No significant changes based on DeltaF [-6.55 (-7.29/-6.08)%] and on visual ratings [1.0 ± 1.0] were observed between t1 and t2 (P = 1.000). After 7 days (t1) the correlation between the quantitative and the qualitative ratings remained significant, weak to moderate (P < 0.002). After 12 months (t2) the correlation was (non-)significant and weak for DeltaF, DeltaQ, and White Spot Area (P ≤ 0.097). LIMITATIONS: Since the overall masking efficacy of resin infiltration has been shown previously, an untreated control group was omitted. CONCLUSIONS: When assessing the masking efficacy of infiltrated post-orthodontic WSL only a weak to moderate correlation was found between QLF values and visual ratings. Furthermore, over time this correlation decreased. Thus, it remains unclear if QLF is a viable method to assess and quantify infiltrated post-orthodontic WSL over time. TRIAL REGISTRATION: German Clinical Trials Register (DRKS-ID:DRKS00005067).

Randomized in situ evaluation of surface polishing protocols on the caries-protective effect of resin Infiltrant.

The aim of this placebo-controlled randomized in situ study was to evaluate the effect of different surface polishing protocols on enamel roughness, bacterial adhesion and caries-protective effect of a resin infiltrant. Seventy-five bovine enamel samples having artificial caries lesions were treated with a resinous infiltrant and afterwards randomly dividided into five polishing protocols: aluminum oxide flexible disks (Al2O3-Disks), silicon carbide tips (SIC-Tips), silicon carbide brush (SIC-Brush), silicon carbide polyester strips (SIC-Strips) or no polishing [negative control (NC)]. Average surface roughness (Ra) was assessed by profilometry. Samples were mounted in palatal appliances under a mesh for biofilm accumulation. Fifteen volunteers wore the intraoral appliances (14-days) and cariogenic challenge was triggered by sucrose solutions. Biofilm formed was collected for microbiological analysis of caries-related bacteria (Streptococcus mutans, Lactobacillus acidophilus) and demineralization was assessed by cross-sectional microhardness. Mean Knoop hardness numbers (Kg/mm2) were plotted over lesion depth (µm) and area under the lesion curve was subtracted from sound enamel to determine demineralization (ΔS, Kg/mm2xµm). Data were analyzed by ANOVA and post-hoc comparisons (α = 0.05). NC resulted in significantly higher Ra means than Al2O3-Disks and SIC-Strips. Bacterial counts were not significantly different between the groups (p > 0.05). Regards ΔS means, however none of the groups were significantly different to NC (6983.3 kg/mm2xµm /CI 4246.1-9720.5, p > 0.05). Conclusions: Polishing protocols (Al2O3-Disks, SIC-Strips) significantly decreseased roughness of infiltrated-enamel, however none of the polishing protocols could signicantly decrease bacterial counts nor resulted in significant less demineralization.

Restoration of teeth affected by molar-incisor hypomineralisation: a systematic review.

The objective was to systematically analyse clinical studies on restorative procedures for teeth affected by molar-incisor hypomineralisation (MIH). The databases PubMed, Embase, and Cochrane Library were searched. Only retrospective and prospective clinical studies dealing with sealing or restoration of MIH-affected teeth were included. The language was restricted to English or German. Thirteen of 36 potentially eligible studies were included focusing on the following subjects: extension of enamel preparation, adhesive procedures prior to restoration, application of fissure sealants as well as restoration with conventional glass ionomer cements (GIC), resin modified glass ionomer cements (RMGIC), resin composites, and indirect restorations. Seven clinical studies were controlled trials. However, only two included MIH-unaffected teeth as control. No meta-analysis was performed due to the heterogeneity of study designs (e.g. severity of MIH or the restorative materials investigated). Based on the present analysis, the annual failure rates were in average 21% for fissure sealants, 22% for GIC, 1-6% for RMGIC, 13-32% for resin composites, and 0-7% for indirect restorations. In summary, only few tendencies can be deduced from this review at a low level of evidence (number of studies): 1) preparation margins in sound enamel seem to be superior to preparations in hypomineralised enamel (1 study), 2) RMGIC seems to be superior to GIC (3 studies), 3) resin composites may be used for restoring all severities of MIH (7 studies) with self-etch and etch-and-rinse adhesive systems generally not performing differently (3 studies), and 4) in cases of severe MIH, indirect restorations showed a good clinical success (4 studies).

Mechanical Properties of Teeth Restored After Selective Caries Excavation. Systematic Review and Meta-Analysis

ABSTRACT: The aim of this study was to systematically review the literature of in vitro studies comparing the mechanical properties of teeth restored after selective caries excavation (SCE) and complete caries excavation (CCE). The PubMed/MEDLINE and EMBASE electronic databases were searched systematically. In vitro studies investigating the mechanical properties of teeth restored after SCE, were independently checked by two authors. Inclusion criteria were: (1) performing SCE (2) mentioning the teeth were later restored, and (3) evaluating mechanical properties of the restored teeth. Meta-analysis was performed with and without discriminating between shallow and deep lesions. From 1,859 potentially eligible studies, 14 were selected for full text analysis and 5 were included in the meta- analysis. Fracture resistance was significantly lower after SCE than after CCE in overall analysis (SMD[95%CI]=-1.62[-3.04,-0.20]) and for deep lesion (SMD[95%CI]=-1.62[-2.62,-0.61]), whereas cuspal deflection at 200 and 400N was significantly higher after SCE than after CCE for discriminated and non- discriminated analyses. Furthermore, for shallow lesions the risk of catastrophic fracture was significantly lower after SCE than CCE (RR[95%CI]=0.58[0.43,0.78]). The included studies presented low and medium risk of bias. The mechanical behavior of restored teeth seems to be affected by the excavation strategy. Although there is a tendency for lower fracture resistance and higher cuspal deflection after SCE, there is a lower risk of catastrophic failure when compared to CCE. However, this conclusion is based on very few in vitro studies.

RESUMEN: El objetivo de este estudio fue revisar sistemáticamente la literatura de estudios in vitro que comparan las propiedades mecánicas de los dientes restaurados después de la excavación selectiva de caries (ESC) y la excavación de caries completa (ECC). Se realizaron búsquedas sistemáticas en las bases de datos electrónicas PubMed / MEDLINE y EMBASE. Los estudios in vitro que investigan las propiedades mecánicas de los dientes restaurados después de la ESC fueron verificados de forma independiente por dos autores. Los criterios de inclusión fueron: (1) realizar ESC (2) mencionar que los dientes fueron posteriormente restaurados y (3) evaluar las propiedades mecánicas de los dientes restaurados. El metanálisis se realizó con y sin discriminación entre lesiones superficiales y profundas. De 1.859 estudios potencialmente elegibles, se seleccionaron 14 para el análisis de texto completo y 5 se incluyeron en el metanálisis. La resistencia a la fractura fue significativamente menor después de ESC que después de CCE en el análisis general (DME [IC del 95 %] = - 1,62 [-3,04, -0,20]) y para la lesión profunda (DME [IC del 95 %] = - 1,62 [-2,62, - 0,61]), mientras que la deflexión de las cúspides a 200 y 400 N fue significativamente mayor después de ESC que después de CCE para análisis discriminados y no discriminados. Además, para las lesiones superficiales, el riesgo de fractura catastrófica fue significativamente menor después de ESC que de CCE (RR [IC 95 %] = 0,58 [0,43,0,78]). Los estudios incluidos presentaron riesgo de sesgo bajo y medio. El comportamiento mecánico de los dientes restaurados parece verse afectado por la estrategia de excavación. Aunque existe una tendencia a una menor resistencia a la fractura y una mayor deflexión de la cúspide después de la ESC, existe un menor riesgo de falla catastrófica en comparación con la CCE. Sin embargo, esta conclusión se basa en muy pocos estudios in vitro.

Improving the Efficiency of Photodynamic Chemotherapy in Root Canals against Enterococcus faecalis In Vitro.

The aim of this study was to evaluate the effect of photoactivated chemotherapy (PACT) on Enterococcus faecalis (E. faecalis) biofilms in root canals using an 90% isopropanol (IPA)-based photosensitizer and removing excess photosensitizer before light incubation. Three hundred and seven extracted human teeth with one root canal were infected with E. faecalis for 72 h and treated in groups: IPA irrigation; PACT; PACT and final rinse with IPA; PACT with photosensitizer removal using either 0.9% NaCl solution or sterile paper points or both; PACT using IPA-based photosensitizer with and without a final rinse of IPA. Root canals were sampled using sterile paper points and dentin chips collected from the root canal walls. Additionally, SEM (Scanning Electron Microscopy) images of the specimens were taken to evaluate the root canal walls for residue bacterial contamination. In all antimicrobial treatment groups treatments E. faecalis counts were significantly reduced in the root canals. Using IPA-based photosensitizer the antimicrobial effect of PACT was significantly enhanced. Irrigation with IPA alone or after PACT significantly increased the antimicrobial effect compared to PACT alone. The collected dentin chips revealed the highest amount of culture negative root canals (10%) after PACT using IPA-based photosensitizer. In the other groups, the culture negative samples ranged from only 0-2 specimens of 30 specimens. REM images show remaining E. faecalis cells on the root canal wall and inside dentin tubules. Using IPA-based photosensitizer significantly enhanced the antimicrobial effect of PACT against E. faecalis in the root canals.

3-dimensional Analysis and Literature Review of the Root Canal Morphology and Physiological Foramen Geometry of 125 Mandibular Incisors by Means of Micro-Computed Tomography in a German Population.

INTRODUCTION: The aim of this study was to examine the root canal system morphology of mandibular incisors by means of micro-computed tomographic imaging. METHODS: The root canal configuration, physiological foramina, frequency of accessory and connecting canals, and the size and shape of the physiological foramina of 125 mandibular incisors were investigated by means of micro-CT and 3-dimensional imaging software. Root canal configuration of the coronal, middle, and apical thirds and the physiological foramina number are described by a 4-digit system code. RESULTS: The most frequent root canal configurations were 1-1-1/1 (56%), 1-2-1/1 (17.6%), and 1-1-1/2 (10.4%); 9 additional different root canal configurations were observed. Single-rooted incisors showed in 80% 1, in 16% 2, and in 4% 3 physiological foramina, respectively. Accessory canals were found in only 13.6% of the investigated teeth. Connecting canals were observed in 36% of the sample, most often in root canal configurations 1-2-1/1 (12.8%) and 2-2-1/1 (7.2%). The morphologic dimensions of a total of 146 physiological foramina were measured. Their mean wide and narrow diameters were 0.24 mm (standard deviation = 0.1 mm) and 0.23 mm (standard deviation = 0.08 mm) when only 1 physiological foramen was present. The physiological foramen shapes observed were oval (56%), round (28.8%), and irregular (15.2%). CONCLUSIONS: The study provides detailed information about the root canal morphology of anterior teeth in a German population. Within the limitations of the study, the authors recommend according to results obtained in this investigation a final physiological foramen preparation size of ISO 30-35; yet, such a decision should be carefully considered on an individual basis.

Effects of Dentifrices Differing in Fluoride Content on Remineralization Characteristics of Dentin in vitro.

OBJECTIVES: The aim of this study was to compare the caries preventive effect of highly fluoridated dentifrices and gels on sound dentin as well as on artificial dentin caries-like lesions. METHODS: Bovine dentin specimens (n = 240), with 2 different surfaces each (1 sound surface [sound treatment (ST)] and one caries lesion [demineralized treatment (DT)]), were prepared and randomly allocated to one highly (6 × 120 min demineralization/day [H]) and one lowly cariogenic (6 × 60 min demineralization/day [L]) pH-cycling model. Treatments during pH-cycling (28 days) were: brushing 2×/day with: 0 ppm F [H0/L0], 1,450 ppm F [H1,450/L1,450], 2,800 ppm F [H2,800/L2,800], 5,000 ppm F [H5,000/L5,000], 5,000 ppm F plus TCP [H5,000+TCP/L5,000+TCP], and 12,500 ppm F [H12,500/L12,500] containing dentifrices/gels. Dentifrice/gel slurries were prepared with deionized water (1:2 wt/wt). Differences in integrated mineral loss (∆∆Z) and ∆ lesion depth were calculated between values before and after pH-cycling using transversal microradiography. RESULTS: The correlation between ΔΔZDT and F- was strong for the highly (rH = 0.691; p < 0.001) and moderate (rL = 0.500; p < 0.001) for the lowly cariogenic model, indicating a fluoride dose-response for both. Significant differences for ΔΔZDT and ΔΔZST could be found between H0, H1,450, H5,000, and H12,500 as well as L0, L5,000, and L125,000 (p ≤ 0.046; analysis of covariance [ANCOVA]). Except for 0 ppm F-, no significant difference in ΔΔZST and ΔΔZDT could be found between the highly and lowly cariogenic model (p ≥ 0.056; ANCOVA). CONCLUSION: For both pH-cycling conditions a dose-response for fluoride could be revealed. For elderly people with exposed root surfaces, the use of gels containing 12,500 ppm F instead of regularly (1,450 ppm F) or highly (5,000 ppm F) fluoridated dentifrices should be further investigated, as it offered higher caries-preventive effects in vitro.

Dentareport - Automated longevity and risk factor analysis in dental patient care.

BACKGROUND AND OBJECTIVE: During routine patient care practitioners have to document several aspects. However, currently it is difficult to methodically analyze the longevity of therapeutic concepts in dental private practice. Thus, the aim of the present paper was to introduce a software (Dentareport) to compare the success of different treatment options and to identify risk factors for failures in dental patient care. METHODS: Dentareport has a digital interface to automatically collect data of electronic patient files of practice management programs. By using computer-aided routines descriptive analyses of the treatments can be visualized. Dentareport also visually displays a bivariate risk factor analysis of treatment options. For this, crude associations between baseline characteristics (e.g. age) and time until failure (e.g. tooth loss) are calculated for the chosen treatment option by fitting separate models for each baseline characteristic as the independent variable. Furthermore, annual failure rates and survival graphs can be displayed. RESULTS: The software has already been used to self-analyze treatment decisions. It highlighted the most long-lasting treatments for specific indications. Risk factors on practice-, patient- and tooth-level were easily identified. Furthermore, the software has been used to collect data for analysis of retrospective practice-based, mono-as well as multi-center observational studies. CONCLUSIONS: By using Dentareport practitioners can easily and objectively self-analyze treatment successes and risk factors. Furthermore, for researchers the software easily generates huge data sets in different fields in dentistry and enables the analysis on a multi-center level. Most relevant factors can, thus, be taken into account for treatment decisions.

Interradicular Root Canals in Mandibular First Molars: A Literature Review and Ex Vivo Study.

INTRODUCTION: Successful endodontic treatment vastly depends to a high degree on an accurate knowledge of root canal system morphology. It is a prerequisite to be aware of all possible reservoirs where bacteria and/or toxins can persist, compromising the surrounding tissues; such knowledge results in endodontic success. METHODS: The presence of interradicular canals and diverticula between the pulp chamber floor and the bifurcation area surface of 117 mandibular first molars was investigated. Access cavities were prepared, the teeth were embedded in plastic, and the pulp chambers were flooded with methylene blue and then centrifuged. An average of 4.2 (0.145 ± 0.03 mm thickness) slices per tooth were obtained by means of a diamond band saw. The presence of interradicular canals and diverticula was investigated using a light microscope (125×). RESULTS: Interradicular canals were observed in 9 teeth. Seven teeth had 1 interradicular canal, and 2 teeth had 2 interradicular canals. Diverticula (blind interradicular canals) were observed in 11 teeth originating either on the pulp chamber floor or the bifurcation side. The number of diverticula per tooth varied between 1 and 5 and originated in 3 teeth in the pulp chamber floor and 8 teeth in the bifurcation area. Two teeth had both 1 interradicular canal and 3 diverticula. Of the 117 mandibular molars investigated, 18 had either 1 or 2 interradicular canals, 1 to 5 diverticula, or an interradicular canal and 3 diverticula. CONCLUSIONS: Based on the results obtained with this ex vivo study and because of the difficulties involved in the clinical performance of mechanical cleaning of possibly existing interradicular canals, it is highly recommended to perform thorough chemical cleaning and disinfection of the pulp chamber floor area in order to enhance the sealing possibility of such structures and minimize treatment failure.

Evaluation of novel nanoscaled metal fluorides on their ability to remineralize enamel caries lesions.

The aim of this in vitro study was to evaluate the ability of two nanoscaled metal fluorides (NMF) to remineralize shallow (SL) and deep (DL) artificial enamel caries lesions. NMF are synthesized via a non-aqueous fluorolytic sol-gel-synthesis and dissolve low fluoride concentration in aqueous solutions (n-CaF2: 7 ppm, n-MgF2: 70 ppm), whilst containing a nominal fluoride concentration of 3,400 ppm. For comparison, an aqueous sodium fluoride solution (NaF: 3,400 ppm), a sodium fluoride containing varnish (Duraphat: 22,600 ppm) and a fluoride-free negative control were investigated. Bovine enamel specimens with SL (n = 86, 4649-4795 vol%xµm) or DL (n = 145, 9091-9304 vol%xµm) were prepared and allocated to five groups each. In each group the respective agent was applied and pH-cycling was performed for 14 days (SL) and 90 days (DL), respectively. Mineral loss and lesion depth were assessed by transversal microradiography. For SL, all fluoride agents significantly remineralized the specimens compared to baseline (p > 0.05; Mann-Whitney test) to a similar extent. For DL, both NMF showed significantly higher mineral gain compared to the other fluoride agents (p < 0.05). In conclusion, the novel NMF- showing relatively low free fluoride concentrations- bear at least the similar potential for remineralization of early caries lesions as highly fluoridated agents being commonly used.

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 (NNB/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 (NNB). 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, NNB, N0, and N1 showed significantly increased ΔZDT/LDDT and ΔZST/LDST values, indicating further demineralization. In contrast, CPP0, CPP1, SDF0, and SDF1 showed significantly decreased ΔZDT/LDDT values, indicating remineralization (p ≤ 0.004; paired t test). CPP0, CPP1, SDF0, and SDF1 showed significantly higher changes in ΔΔZDT/ΔLDDT and ΔΔZST/ΔLDST than NNB, 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 (NNB). 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, NNB, N0, N1, T0, and E0 showed significantly increased ΔZ and LD values after pH-cycling (p ≤ 0.003; paired t test). C0, C1, NNB, 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.

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 (x0394;x0394;Z) and lesion depth (x0394;LD) 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 x0394;x0394;Z of the dentifrice with 0 ppm F, sound surfaces showed significantly higher x0394;x0394;Z and x0394;LD 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.

Remineralizing efficacy of a CPP-ACP cream on enamel caries lesions in situ.

The aim of this double-blind, randomized, cross-over in situ study was to compare the remineralizing effects induced by the application of casein phosphopeptide-stabilized amorphous calcium phosphate complexes (CPP-ACP)-containing cream (without fluoride) after the use of fluoride toothpaste with the prolonged use of fluoride toothpaste on enamel caries lesions in situ. During each of three experimental legs of 4 weeks, 13 participants wore intra-oral mandibular appliances with 8 pre-demineralized bovine enamel specimens in the vestibular flanges mimicking either 'easily cleanable' or 'proximal' surfaces (n = 312). The three randomly allocated treatments were as follows: (1) application of CPP-ACP-containing cream (GC Tooth Mouse, non-fluoride) after the use of fluoride toothpaste (1,400 ppm NaF; TM), (2) prolonged application of fluoride toothpaste (1,400 ppm NaF; positive control, PC) and (3) prolonged application of fluoride-free toothpaste (negative control, NC). Additionally, one of each of the two flanges was brushed twice daily with the respective toothpaste. The differences in integrated mineral loss as assessed by transversal microradiography were calculated between values before and after the in situ period. Changes in mineral loss were analysed for those pairs of subgroups differing in only one of the three factors (intervention, brushing and position). The PC treatment induced a significantly higher mineral gain compared with the TM and NC treatments. No significant differences between TM and NC for both positions were observed. In conclusion, the additional use of a CPP-ACP-containing cream seems to be less efficacious in remineralizing caries lesions than the prolonged application of fluoride toothpaste.