Systematic review and network meta-analysis of restorative therapy and adhesive strategies in root caries lesions

AIM

This systematic review and network meta-analysis (NMA) aimed to establish a clinically relevant hierarchy of the different adhesive and/or restorative approaches to restore cavitated root caries lesions through the synthesis of available evidence.

MATERIALS AND METHODS

A systematic search was conducted in Medline/Web of Science/Embase/ Cochrane Library/Scopus/grey literature. RCTs investigating ≥2 restorative strategies (restorative /adhesive materials) for root caries lesions in adult patients were included. Risk of bias within studies was assessed (Cochrane_RoB-2) and the primary outcome was survival rate of restorations at different follow-up times (6-/12-/24-months). Network meta-analyses were conducted using a random effects model stratified by follow-up times. I2-statistics assessed the ratio of true to total variance in the observed effects. All available combinations of adhesives (1-SE: one-step self-etch; 2-3ER: two-/three-step etch-and-rinse) and restorative materials (conventional composite (CC) as well as conventional and resin-modified glass ionomer cements (GIC, RMGIC)) were included. Risk of bias across studies and confidence in NMA (CINeMA) were assessed.

RESULTS

547 studies were identified and nine were eligible for the NMA. In total, 1263 root caries lesions have been restored in 473 patients in the included clinical trials. Patients involved were either healthy (n = 6 trials), living in nursing homes (n = 1 trial) or received head-and-neck radiotherapy (n = 2 trials). There was statistically weak evidence to favour either of material/material combination regarding the survival rate. A tendency for higher survival rate (24-months) was observed for 2-3ER/CC (OR24mths 2.65; 95%CI=1.45/4.84) as well as RMGIC (OR24mths 2.05; 95%CI=1.17/3.61) compared to GIC. These findings were though not statistically significant and confidence of the NMA was low.

CONCLUSION

An evidence-based choice of restorative strategy for managing cavitated root caries lesions is currently impossible. There is a clear need for more standardised, well-designed RCTs evaluating the retention rate of root caries restoration approaches.

Success and complication rates of non-precious alloy telescopic crowns in a general dental practice

OBJECTIVES

This retrospective, single-center, practice-based cohort study aimed to analyze factors associated with the success of removable partial dentures retained by telescopic crowns (TRPD).

MATERIALS AND METHODS

TRPD which were placed in a single practice of a practice-based research network were analyzed. Data from 139 patients (age (SD): 66 (11) years; 66 female) with 174 TRPD including 488 non-precious alloy telescopic crowns (TC) between 2004 and 2016 were included. TC without any technical complication were considered as successful, and as survived, if they were still in function at the last check-up. Multilevel Cox proportional hazard models were used to evaluate the association between clinical factors and time until failure.

RESULTS

Within a mean follow-up period (SD) of 4.2 (3.3) years (min-max: 1 day-12 years), 372 (76%) TC (AFR5years,TC-level: 5.0%) as well as 136 (87%) TRPD (AFR5years,TRPD-level: 5.1%) ("worst-case scenario") and 150 (86%) TRPD (AFR5years,TRPD-level: 3.4%) ("best-case scenario") were considered as successful. The main failure types were recementation (n = 39), endodontic treatment (n = 36), and extraction (n = 35). TC in male patients showed 1.6 times higher risk for failure than in female patients (95%CI: 1.1-2.4; p = 0.023). TC on premolars showed 2.2 times higher risk for failure than on incisors (95%CI: 1.1-5.0; p = 0.023) and TC in dentures with ≤ 3TC showed 2.1 times higher risk for failure than TC in dentures with > 3TC (1.3-3.4; p = 0.042). Furthermore, TC on the most distal tooth in an arch showed 2.4 times higher risk for failure than TC on a more mesial tooth (1.5-3.8; p < 0.001).

CONCLUSION

For removable partial dentures retained by telescopic crowns, high success rates could be found after up to 12 years. Patient-level and tooth-level factors were significantly associated with failure.

CLINICAL RELEVANCE

For removable partial dentures retained by telescopic crowns, high success rates could be found after up to 12 years. Patient-level and tooth-level factors were significantly associated with failure.

Multi-modal deep learning for automated assembly of periapical radiographs

OBJECTIVES

Periapical radiographs are oftentimes taken in series to display all teeth present in the oral cavity. Our aim was to automatically assemble such a series of periapical radiographs into an anatomically correct status using a multi-modal deep learning model.

METHODS

4,707 periapical images from 387 patients (on average, 12 images per patient) were used. Radiographs were labeled according to their field of view and the dataset split into a training, validation, and test set, stratified by patient. In addition to the radiograph the timestamp of image generation was extracted and abstracted as follows: A matrix, containing the normalized timestamps of all images of a patient was constructed, representing the order in which images were taken, providing temporal context information to the deep learning model. Using the image data together with the time sequence data a multi-modal deep learning model consisting of two residual convolutional neural networks (ResNet-152 for image data, ResNet-50 for time data) was trained. Additionally, two uni-modal models were trained on image data and time data, respectively. A custom scoring technique was used to measure model performance.

RESULTS

Multi-modal deep learning outperformed both uni-modal image-based learning (p<0.001) and time-based learning (p<0.05). The multi-modal deep learning model predicted tooth labels with an F1-score, sensitivity and precision of 0.79, respectively, and an accuracy of 0.99. 37 out of 77 patient datasets were fully correctly assembled by multi-modal learning; in the remaining ones, usually only one image was incorrectly labeled.

CONCLUSIONS

Multi-modal modeling allowed automated assembly of periapical radiographs and outperformed both uni-modal models. Dental machine learning models can benefit from additional data modalities.

CLINICAL SIGNIFICANCE

Like humans, deep learning models may profit from multiple data sources for decision-making. We demonstrate how multi-modal learning can assist assembling periapical radiographs into an anatomically correct status. Multi-modal learning should be considered for more complex tasks, as clinically a wealth of data is usually available and could be leveraged.

Evaluation of the masking efficacy of caries infiltration in post-orthodontic initial caries lesions: 1-year follow-up

OBJECTIVES

This study aimed to qualitatively and quantitatively assess the masking efficacy and color stability of resin infiltration on post-orthodontic ICL after 1 year.

MATERIALS AND METHODS

In 17 adolescents, 112 ICL (ICDAS-1: n = 1; ICDAS-2: n = 111) in 112 teeth were treated by resin infiltration (Icon, DMG) 3 to 12 months after bracket removal. The etching procedure was performed up to 3 times. Standardized digital images were taken before treatment (T0), 7 days (T7) and 12 months (T365) after treatment. Outcomes included the evaluation of the color differences between infiltrated and healthy enamel at T0, T7, and T365 by quantitative (colorimetric analysis (ΔE), ICDAS scores) and qualitative methods (5-point Likert scale (deteriorated (1), unchanged (2), improved, but not satisfying (3), improved and no further treatment required (4), completely masked (5)).) Differences between time points were analyzed by using Friedman test (ΔΕ) and chi-square tests (ICDAS).

RESULTS

The median color difference (25th/75th percentiles) between carious and healthy enamel at baseline (ΔΕ0) was 10.2(7.7/13.6). A significant decrease was observed 7 days after treatment (ΔΕ7 = 3.1(1.8/5.0); p < 0.001; ICDAS; p < 0.001). No significant changes based on ΔΕ (p = 1.000), and ICDAS grade (p = 0.305) were observed between T7 and T365 (ΔΕ12 = 3.4 (1.8/4.9)). Furthermore, at T365 four experienced dentists classified 55% and 39% of the lesions as "improved and no further treatment required" and "completely masked," respectively (Fleiss kappa: T365 = 0.851 (almost perfect)).

CONCLUSION

Resin infiltration efficaciously masked post-orthodontic ICL 7 days and 12 months after treatment. These results for most of the teeth could not only be observed by quantitative but also by qualitative analysis.

CLINICAL RELEVANCE

Resin infiltration efficaciously masks post-orthodontic initial carious lesions. The optical improvement can be observed directly after treatment and remains stable for at least 12 months.

Artificial Intelligence for Caries Detection: Value of Data and Information

If increasing practitioners’ diagnostic accuracy, medical artificial intelligence (AI) may lead to better treatment decisions at lower costs, while uncertainty remains around the resulting cost-effectiveness. In the present study, we assessed how enlarging the data set used for training an AI for caries detection on bitewings affects cost-effectiveness and also determined the value of information by reducing the uncertainty around other input parameters (namely, the costs of AI and the population’s caries risk profile). We employed a convolutional neural network and trained it on 10%, 25%, 50%, or 100% of a labeled data set containing 29,011 teeth without and 19,760 teeth with caries lesions stemming from bitewing radiographs. We employed an established health economic modeling and analytical framework to quantify cost-effectiveness and value of information. We adopted a mixed public–private payer perspective in German health care; the health outcome was tooth retention years. A Markov model, allowing to follow posterior teeth over the lifetime of an initially 12-y-old individual, and Monte Carlo microsimulations were employed. With an increasing amount of data used to train the AI sensitivity and specificity increased nonlinearly, increasing the data set from 10% to 25% had the largest impact on accuracy and, consequently, cost-effectiveness. In the base-case scenario, AI was more effective (tooth retention for a mean [2.5%–97.5%] 62.8 [59.2–65.5] y) and less costly (378 [284–499] euros) than dentists without AI (60.4 [55.8–64.4] y; 419 [270–593] euros), with considerable uncertainty. The economic value of reducing the uncertainty around AI’s accuracy or costs was limited, while information on the population’s risk profile was more relevant. When developing dental AI, informed choices about the data set size may be recommended, and research toward individualized application of AI for caries detection seems warranted to optimize cost-effectiveness.

Benchmarking Deep Learning Models for Tooth Structure Segmentation

A wide range of deep learning (DL) architectures with varying depths are available, with developers usually choosing one or a few of them for their specific task in a nonsystematic way. Benchmarking (i.e., the systematic comparison of state-of-the art architectures on a specific task) may provide guidance in the model development process and may allow developers to make better decisions. However, comprehensive benchmarking has not been performed in dentistry yet. We aimed to benchmark a range of architecture designs for 1 specific, exemplary case: tooth structure segmentation on dental bitewing radiographs. We built 72 models for tooth structure (enamel, dentin, pulp, fillings, crowns) segmentation by combining 6 different DL network architectures (U-Net, U-Net++, Feature Pyramid Networks, LinkNet, Pyramid Scene Parsing Network, Mask Attention Network) with 12 encoders from 3 different encoder families (ResNet, VGG, DenseNet) of varying depth (e.g., VGG13, VGG16, VGG19). On each model design, 3 initialization strategies (ImageNet, CheXpert, random initialization) were applied, resulting overall into 216 trained models, which were trained up to 200 epochs with the Adam optimizer (learning rate = 0.0001) and a batch size of 32. Our data set consisted of 1,625 human-annotated dental bitewing radiographs. We used a 5-fold cross-validation scheme and quantified model performances primarily by the F1-score. Initialization with ImageNet or CheXpert weights significantly outperformed random initialization (P < 0.05). Deeper and more complex models did not necessarily perform better than less complex alternatives. VGG-based models were more robust across model configurations, while more complex models (e.g., from the ResNet family) achieved peak performances. In conclusion, initializing models with pretrained weights may be recommended when training models for dental radiographic analysis. Less complex model architectures may be competitive alternatives if computational resources and training time are restricting factors. Models developed and found superior on nondental data sets may not show this behavior for dental domain-specific tasks.

A prospective, multi-center, practice-based cohort study on all-ceramic crowns

OBJECTIVES

The aim of this prospective, multi-center, practice-based cohort study was to analyze factors associated with the success of all-ceramic crowns.

METHODS

All-ceramic crowns placed in a practice-based research network ([Ceramic Success Analysis, AG Keramik) were analyzed. Data from 1254 patients with (mostly in-office CAD/CAM) all-ceramic crowns placed by 101 dentists being followed up for more than 5 years were evaluated. At the last follow-up visit crowns were considered as successful (not failed) if they were sufficient, whereas crowns were considered as survived (not lost) if they were still in function. Multi-level Cox proportional hazards models were used to evaluate the association between a range of predictors and time of success or survival.

RESULTS

Within a mean follow-up period (SD) of 7.2(2)years [maximum:15years] 776 crowns were considered successful (annual failure rate[AFR]:8.4%) and 1041 crowns survived (AFR:4.9%). The presence of a post in endodontically treated teeth resulted in a risk for failure 2.7 times lower than that of restorations without a post (95%CI:1.4-5.0;p = 0.002). Regarding the restorative material and adhesive technique, hybrid composite ceramics and single-step adhesives showed a 3.4 and 2.2 times higher failure rate than feldspathic porcelain and multi-step adhesives, respectively (p < 0.001). Use of an oxygen-blocking gel as well as an EVA instrument resulted in a 1.5-1.8 times higher failure rate than their non-use (p ≤ 0.001).

SIGNIFICANCE

After up to 15years AFR were rather high for all-ceramic crowns. Operative factors, but no patient- or tooth-level factors were significantly associated with failure. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00020271).

Risk Factors for Failure of Direct Restorations in General Dental Practices

The aim of this retrospective noninterventional multicenter practice-based study was to analyze factors influencing the survival of direct restorations. Records from patients who visited 5 private practices regularly were searched for the presence of direct restorations. Data were recorded from 7,858 patients with 27,407 direct restorations being detected at least 6 mo before the last recall visit. Multilevel Cox proportional hazard models were used to evaluate the association between clinical factors and time until failure. Within 228 mo, 5,493 failures could be observed. Median survival time was 207 mo. The annual failure rates were 3.8%, 4.0%, 4.6%, 4.9%, and 3.9% for class I, II, III, IV, and V restorations, respectively. Class II and IV restorations showed a 1.1-times (95% CI, 1.0 to 1.2) and 1.2-times (95% CI, 1.1 to 1.2) higher failure rate than class I restorations ( P ≤ 0.029). Patients aged <20 y and >60 y showed up to a 1.4-times higher failure rate than patients aged 20 to 60 y ( P ≤ 0.015). Restorations that underwent check-up twice a year or more showed a significantly higher failure rate than those that did so less than twice a year ( P < 0.001). Furthermore, the dentists significantly influenced time until failure ( P < 0.001). Regarding the restorative material, composites showed up to a 2.1-times longer time until failure than GIC ( P ≤ 0.020). Moderate failure rates were observed for direct restorations in the private practice setting after up to 18.5 y. Within the limitations of the present study, several factors on the levels of practice (i.e., dentist), patient (i.e., age), and tooth (i.e., restorative material, restored surfaces according to the classification of Black) were significant predictors for the failure rate. Therefore, treatment decision should take into account most relevant factors (German Clinical Trials Register DRKS00015228).

Evaluation of the value of re-wetting prior to resin infiltration of post-orthodontic caries lesions

OBJECTIVES

Assessment of the influence of colour changes during the re-wetting process as a possible predictor for the final result after resin infiltration to mask post-orthodontic white spot lesions.

MATERIALS AND METHODS

Resin infiltration (ICON; DMG, Hamburg, Germany) was performed according to the manufacturer's recommendation with the exception of repeated, at maximum three etching procedures based on the subjective decision of the dentist during a so called re-wetting process using ethanol. The masking effect by ethanol as well as after resin infiltration was evaluated by digital images taken before, for nine seconds during re-wetting and one week after treatment using CIE L*a*b* colour space.

RESULTS

Twenty-nine patients (16 female) with a total of 221 lesions (ICDAS 2) were included (mean age 16 years). Mean time after debonding the orthodontic appliances was ten weeks. Colour changes during re-wetting, evaluated in the first ten patients (71 lesions) showed a significant correlation between the minimum ΔE observed during re-wetting and the final ΔE after resin infiltration (r = 0.65, p < 0.001; Spearman correlation). The main drop in ΔE becomes visible after three seconds when performing the re-wetting process. Regarding the 221 lesions, resin infiltration significantly reduced the colour difference between sound and lesion areas from a baseline ΔE (25^th/75^th percentiles) of 10.9 (8.2/13.2) to a ΔE of 4 (2.1/5.8) after one week (p < 0.001). The number of etching procedures correlated significantly with baseline ΔE (p < 0.05).

CONCLUSIONS

The minimum ΔE observed during the re-wetting process seems to be a useful predictor for the final result of resin infiltration of post-orthodontic caries lesions. More prominent lesions with higher ΔE at baseline seem to require more erosion of the surface layer. In general, a significant and considerable clinical reduction of ΔE could be observed.

CLINICAL SIGNIFICANCE

We corroborate that resin infiltration technique is a very useful method to mask caries lesions having developed during treatment with fixed orthodontic appliances. Colour changes while re-wetting the lesions with ethanol seem to be a valuable indicator for the number of required etching procedures.

Success and survival of post-restorations: six-year results of a prospective observational practice-based clinical study

AIM

This prospective, noninterventional, multi-centre, practice-based study aimed to evaluate the longevity of endodontically treated teeth (ETT) restored with posts and to analyse factors influencing the success and survival of endodontic posts.

METHODOLOGY

Eight general dental practitioners each placed up to 27 endodontic posts without any restriction to size and material. Teeth were restricted to incisors, canines and premolars. Multi-level Cox proportional hazards models were used to evaluate the association between clinical factors and time until failure.

RESULTS

A total of 195 endodontic posts were followed-up for up to 6.5 years in 195 patients. Of these, 140 posts were judged as successful [mean success time: 59 (55-63) months]; the mean annual failure rate was 8.6%. This decreased to 4.4% when excluding recementations. 152 posts survived [mean survival time: 64 (60-67) months]. Recemented restorations had an eight times higher failure rate compared with new restorations. Furthermore, restorations with glass fibre post had a significantly lower success rate compared with titanium posts.

CONCLUSION

Relatively low success and survival rates occurred for restorations with posts after root canal treatment in a private practice setting after a follow-up of up to 6.5 years. Recemented crowns had a high risk of failure.

Modified resin infiltration of non-, micro- and cavitated proximal caries lesions in vitro

OBJECTIVE

Infiltrant resin (IR) is currently indicated for non-cavitated caries lesions. However, modifying the technique might expand its indication spectrum to micro-cavitated lesions. The present study aimed to evaluate the penetration/filling ability of a newly developed micro-filled infiltrant resin (MFIR) in non-, micro- and cavitated natural caries lesions.

MATERIALS AND METHODS

Proximal lesions in 120 extracted human teeth with ICDAS-2 (n = 30), 3 (n = 45) and 5 (n = 45) lesions were etched with 15% hydrochloric acid gel for 2 min and allocated to one of the following treatments; IR: lesions (ICDAS-2, 3 and 5; each n = 15) were treated with commercial infiltrant resin for 3 min. MFIR: experimental MFIR [55 wt% IR plus 45 wt% organic fillers] was applied to lesions (ICDAS-2, 3 and 5; each n = 15) for 3 min. IR + FC: IR was applied for 3 min, light-cured, and cavities (ICDAS-3 and 5; each n = 15) filled with flowable composite (FC). Percentage infiltration of the demineralized enamel (Inf.%) and percentage filling of the cavity (Fill.%) were analyzed using dual-fluorescence staining and confocal microscopy.

RESULTS

No significant differences in Inf.% (range of medians: 57%-100%) were observed between different treatments (p > 0.05; Kruskal-Wallis) within each ICDAS-code. Fill.% of cavities was significantly higher in groups MFIR (median in ICDAS-3/-5: 100%/100%) and IR + FC (100%/100%) than IR (25%/38%) (p < 0.05).

CONCLUSION

MFIR showed similar penetration into natural lesions as the commercial infiltrant, but better ability to fill cavitated areas.

CLINICAL RELEVANCE

MFIR and IR + FC might provide a new micro-invasive treatment for small cavitated proximal lesions.

A New Laser-Processing Strategy for Improving Enamel Erosion Resistance

In the present study, a new automatic laser-processing strategy allowing standardized irradiation of natural tooth areas was investigated. The objective was to find a combination of laser parameters that could cause over a 600°C temperature increase at the enamel surface while not damaging enamel, avoiding temperature change above 5.5°C in the pulp and increasing enamel erosion resistance. Seventy-seven bovine enamel samples were randomly divided into 6 laser groups and 1 negative control (C/no treatment/ n = 11). A scanning strategy (7 × 3 mm) was used for the CO₂ laser treatment (λ = 10.6 µm, 0.1-18 J/cm²) with different pulse durations-namely, 20 µs (G20), 30 µs (G30), 55 µs (G55), and 490 µs (G490), as well as 2 modified pulse distances (G33d, G40d). Measurements of temperature change were performed at the surface (thermal camera/50 Hz), at the underside (thermocouples), and at the pulp chamber using a thermobath and human molars ( n = 10). In addition, histology and X-ray diffraction (XRD/ n = 10) were performed. Erosion was tested using an erosive cycling over 6 d, including immersion in citric acid (2 min/0.05 M/pH = 2.3) 6 times daily. Surface loss was measured using a profilometer and statistical analysis with a 2-way repeated-measures analysis of variance (α = 0.05). Only G20 fulfilled the temperature requirements at the surface (619 ± 21.8°C), at the underside (5.3 ± 1.4°C), and at the pulp (2.0 ± 1.0°C), and it caused no mineral phase change and significant reduction of enamel surface loss (-13.2 ± 4.0 µm) compared to C (-37.0 ± 10.1 µm, P < 0.05). A laser-scanning strategy (20 µs/2 kHz/1.25 J/cm², 3.4 mm/s) has been established that fulfilled the criteria for biological safety and significantly increased enamel erosion resistance (64%) in vitro.

When and How to Intervene in the Caries Process

The decrease in caries prevalence in many industrialized countries and the improved knowledge about the etiology and pathogenesis of caries have shifted the focus of caries therapy over the past decades toward less invasive approaches. Studies on caries progression indicate that it is generally quite slow in most patients today which should lead to a reconsideration of the practice of early invasive intervention. Today noninvasive (eg, fluorides) and microinvasive (occlusal sealing, proximal infiltration) therapeutic options that address etiological factors are gaining importance. The goal of these therapies is to heal or at least to slow down the progress of the disease. Noninvasive treatments are mainly related to controlling pathogenic factors (ie, sugar consumption) and enhancing protective factors (mainly oral hygiene and fluorides). Microinvasive treatments do not rely on the compliance of the patient as much, since these treatments include a resinous material that is applied to serve as a diffusion barrier for acids formed by cariogenic bacteria in the overlying plaque. To establish a minimum intervention treatment strategy for caries, the disease must be diagnosed at an early stage. In addition to assessing caries lesions in single teeth, individual risk factors need to be identified so that the underlying causes related to patients' behavioral patterns that led to the disease can be addressed as well. The patient should be informed about the scientific evidence related to the treatment choices in a participative atmosphere. Decision trees may help to make the range of findings comprehensible and the therapeutic shared decision-making process understandable to the patients.

Criteria for the Replacement of Restorations: Academy of Operative Dentistry European Section

The replacement of a restoration is one of the most common procedures in dentistry. However, the criteria for such intervention, excluding catastrophic failure and persistent discomfort and pain, continue to be the subject of considerable debate. The decision-making process remains subjective on the part of the treating clinician, while the evidence base for refurbishment and repair rather than replacement for the management of defective and failing restorations continues to grow and strengthen. This article, prepared as an Academy of Operative Dentistry European Section consensus publication, reviews existing criteria for the replacement of restorations and encourages practitioners to shift, if not already doing so, to considering the replacement of a restoration as a last resort rather than as a prudent action to be taken if in any doubt about clinical acceptability. Further research in the area, spanning the risk assessment of defective and failing restorations and new diagnostic tools and processes, together with work to enhance the evidence base of restoration repair vs replacement, would be of immense value.

Effects of dentifrices differing in fluoride compounds on artificial enamel caries lesions in vitro

The aim of this study was to compare the caries-preventive effect of a stabilized stannous fluoride/sodium fluoride dentifrice containing sodium hexametaphosphate with those of a regular, solely sodium fluoride-containing and amine fluoride-containing dentifrice on pre-demineralized bovine enamel specimens using a pH-cycling model. Bovine enamel specimens with two artificial lesions each were prepared. Baseline mineral loss of both lesions was analyzed using transversal microradiography (TMR). Eighty-five specimens with a mean (SD) baseline mineral loss of 3393 (683) vol% × µm were selected and randomly allocated to five groups (n = 13/15). Treatments during pH-cycling (28 days and 2 × 20 min demineralization/day) were: brushing twice daily with slurries of AmF (1400 ppm F^-), NaF (1450 ppm F^-), SnF₂/NaF (1100 ppm F^-/350 ppm F^-), and fluoride-free (FF) dentifrices or they were immersed in distilled water and remained unbrushed (NB). Subsequently, from each specimen one lesion was covered with acid-resistant varnish, while the remaining lesion was demineralized for another 14 days. Differences in integrated mineral loss (∆∆Z) were calculated between values before and after pH-cycling (∆∆Z _E1) as well as before pH-cycling and after second demineralization (∆∆Z _E2) using TMR. Treatments AmF and NaF induced a significantly higher mineral gain (∆∆Z _E1/∆∆Z _E2) compared to treatments FF and NB (p < 0.05; ANOVA test). Except for treatments AmF and NaF no significant differences in mineral loss between before and after pH-cycling could be observed (p < 0.05; t test) [∆∆Z _E1: AmF:1563 (767); NaF:1222 (1246); SnF₂/NaF:258 (1259); FF:-52 (1223); NB:-151 (834)]. Both dentifrices with either AmF or NaF promoted remineralization, whereas SnF₂/NaF dentifrice did not promote remineralization in a biofilm-free pH-cycling model.

Pragmatic RCT on the Efficacy of Proximal Caries Infiltration

Proximal caries infiltration has been shown to be efficacious in hampering caries lesion progression when performed by dentists working in a university setting. The aim of this randomized split-mouth, placebo-controlled clinical trial was to assess the efficacy of resin infiltration of proximal caries lesions being performed by several dentists in private practices, in combination with individualized oral hygiene plus noninvasive measures compared with these alone. In this study, 87 children and young adults (with 238 pairs of proximal caries lesions radiographically extending into the inner half of the enamel [E2] or the outer third of the dentin [D1]) were randomly allocated to either 1 of 2 treatments. Test lesions were infiltrated, and a mock treatment was performed in control lesions by 5 German private practitioners. All patients received instructions for a noncariogenic diet, flossing and fluoridation, and individualized noninvasive interventions. The primary outcome was radiographic lesion progression (pairwise comparison) evaluated independently by 2 evaluators who were blinded to treatment allocation. After approximately 10 mo (mean ± SD 307 ± 43 d), 92 of 148 lesion pairs in 24 of 38 treated patients who were at high caries risk could be re-evaluated clinically as well as radiographically using individualized bitewing holders, as at baseline; 186 of 204 lesion pairs in 70 of 77 patients (35 of 38 high-risk patients) could be evaluated after 18 mo (mean 542 ± 110 d). No unwanted effects were observed. After 10 mo, progression was recorded in 2 of 92 test lesions (2%) and in 22 of 92 control lesions (24%) ( P = 0.001, McNemar/Obuchowski test; relative risk reduction, 91; 95% confidence interval, 62%–98%). After 18 mo, lesion progression was recorded in all included patients in 10 of 186 test lesions (5%) and in 58 of 186 control lesions (31%) ( P < 0.001; relative risk reduction, 83; 95% confidence interval, 67%–91%). Thus, resin infiltration seems to be more efficacious in reducing lesion progression compared with individualized noninvasive measures alone over a period of 18 mo when performed in a private practice setting by various practitioners (German Clinical Trials Register / Deutsches Register Klinischer Studien DRKS00009963).

Detecting and treating occlusal caries lesions: a cost-effectiveness analysis

The health gains and costs resulting from using different caries detection strategies might not only depend on the accuracy of the used method but also the treatment emanating from its use in different populations. We compared combinations of visual-tactile, radiographic, or laser-fluorescence-based detection methods with 1 of 3 treatments (non-, micro-, and invasive treatment) initiated at different cutoffs (treating all or only dentinal lesions) in populations with low or high caries prevalence. A Markov model was constructed to follow an occlusal surface in a permanent molar in an initially 12-y-old male German patient over his lifetime. Prevalence data and transition probabilities were extracted from the literature, while validity parameters of different methods were synthesized or obtained from systematic reviews. Microsimulations were performed to analyze the model, assuming a German health care setting and a mixed public-private payer perspective. Radiographic and fluorescence-based methods led to more overtreatments, especially in populations with low prevalence. For the latter, combining visual-tactile or radiographic detection with microinvasive treatment retained teeth longest (mean 66 y) at lowest costs (329 and 332 Euro, respectively), while combining radiographic or fluorescence-based detections with invasive treatment was the least cost-effective (<60 y, >700 Euro). In populations with high prevalence, combining radiographic detection with microinvasive treatment was most cost-effective (63 y, 528 Euro), while sensitive detection methods combined with invasive treatments were again the least cost-effective (<59 y, >690 Euro). The suitability of detection methods differed significantly between populations, and the cost-effectiveness was greatly influenced by the treatment initiated after lesion detection. The accuracy of a detection method relative to a "gold standard" did not automatically convey into better health or reduced costs. Detection methods should be evaluated not only against their criterion validity but also the long-term effects resulting from their use in different populations.

Systematic review on noninvasive treatment of root caries lesions

The present systematic review critically summarizes results of clinical studies investigating chemical agents to reduce initiation or inactivation of root caries lesions (RCLs). Outcomes were DMFRS/DFRS (decayed, missing, filled root surfaces), surface texture (hard/soft), and/or RCI (root caries index). Three electronic databases were screened for studies from 1947 to 2014. Cross-referencing was used to further identify articles. Article selection and data abstraction were done in duplicate. Languages were restricted to English and German. Mean differences (MD) were calculated for changes in DMFRS/DFRS. Risk ratios (RR) were calculated for changes in surface texture and RCI in a random effects model. Thirty-four articles with 1 or more agents were included; they reported 30 studies with 10,136 patients who were 20 to 101 y old; and they analyzed 28 chemical agents (alone or in combination). Eleven studies investigated dentifrices, 10 rinses, 8 varnishes, 3 solutions, 3 gels, and 2 ozone applications. Meta-analyses revealed that dentifrices containing 5,000 ppm F(-) (RR = 0.49; 95% confidence interval [95% CI] = 0.42, 0.57; high level of evidence) or 1.5% arginine plus 1,450 ppm F(-) (RR = 0.79; 95% CI = 0.64, 0.98; very low level) are more effective in inactivating RCLs than dentifrices containing 1,100 to 1,450 ppm F(-). Self-applied AmF/SnF2-containing dentifrice and rinse decreased the initiation of RCLs when compared with NaF products (standardized MD = 0.15; 95% CI = -0.22, 0.52; low level). Patients rinsing with a mouth rinse containing 225 to 900 ppm F(-) revealed a significantly reduced DMFRS/DFRS (MD = -0.18; 95% CI = -0.35, -0.01; low level) when compared with a placebo rinse. Significantly reduced RCI was found for CHX (MD = -0.67; 95% CI = -1.01, -0.32; very low level) as well as SDF (MD = -0.33; 95% CI = -0.39, -0.28; very low level) when compared with placebo varnish. Regular use of dentifrices containing 5,000 ppm F(-) and quarterly professionally applied CHX or SDF varnishes seem to be efficacious to decrease progression and initiation of root caries, respectively. However, this conclusion is based on only very few well-conducted randomized controlled trials.

Radiopaque Tagging Masks Caries Lesions following Incomplete Excavation in vitro

One-step incomplete excavation seals caries-affected dentin under a restoration and appears to be advantageous in the treatment of deep lesions. However, it is impossible to discriminate radiographically between intentionally left, arrested lesions and overlooked or active lesions. This diagnostic uncertainty decreases the acceptance of minimally invasive excavation and might lead to unnecessary re-treatment of incompletely excavated teeth. Radiopaque tagging of sealed lesions might mask arrested lesions and assist in discrimination from progressing lesions. Therefore, we microradiographically screened 4 substances (SnCl2, AgNO3, CsF, CsCH3COO) for their effect on artificial lesions. Since water-dissolved tin chloride (SnCl2×Aq) was found to stably mask artificial lesions, we then investigated its radiographic effects on progressing lesions. Natural lesions were incompletely excavated and radiopaque tagging performed. Grey-value differences (△GV) between sound and carious dentin were determined and radiographs assessed by 20 dentists. While radiographic effects of SnCl2×Aq were stable for non-progressing lesions, they significantly decreased during a second demineralization ( p < .001, t test). For natural lesions, tagging with SnCl2×Aq significantly reduced △GV ( p < .001, Wilcoxon). Tagged lesions were detected significantly less often than untagged lesions ( p < .001). SnCl2×Aq was suitable to mask caries-affected dentin and discriminate between arrested and progressing lesions in vitro. Radiopaque tagging could resolve diagnostic uncertainties associated with incomplete excavation.

Cost-effectiveness of One- and Two-step Incomplete and Complete Excavations

The treatment of deep caries lesions carries significant risks for the integrity of the pulp and often initiates a cascade of re-interventions. Incomplete caries removal may reduce these risks and avoid or delay re-treatment. The present study analyzed the cost-effectiveness of one- and two-step incomplete as well as complete excavations. We used Markov models to simulate treatment of a molar tooth with a deep caries lesion in a 15-year-old patient. Retention of the tooth and its vitality as effectiveness measures as well as accruing costs were analyzed over the patient’s lifetime. The model adopted a public-private-payer perspective within German health care. Transition probabilities were calculated based on literature reviews. Monte-Carlo microsimulations were performed with 6-month cycles. One-step incomplete excavation resulted in lower long-term costs and in longer-retained teeth and their vitality (means: 53.5 and 41.0 yrs) compared with two-step incomplete (52.5 and 37.5 yrs) and complete excavations (49.5 and 31.0 yrs), and dominated the other strategies in 70% to 100% of simulations. Regardless of the assumed willingness-to-pay ceiling value, one-step incomplete excavation had the highest probability of being cost-effective. Despite limited evidence levels of input data, we expect one-step incomplete excavation to reduce costs while retaining deeply carious teeth and their vitality for longer.

Attitudes and behaviour regarding deep dentin caries removal: a survey among German dentists

Incomplete removal of deep caries has been shown to reduce the risks of pulp exposure and postoperative pulpal complications. It is therefore of interest whether dentists perform one- or two-step incomplete excavation, and which criteria and methods they use to assess and provide removal of deep caries. This study investigated the attitudes and behaviour of dentists in northern Germany using a new, validated questionnaire. The survey included 2,346 practitioners, 821 (35%) of whom responded. Demographic and sensitivity analysis did not indicate selection bias. 50% of dentists considered only complete excavation, even if pulp exposure was likely. If caries was to be removed incompletely, 77% considered two-step excavation. Hardness was the most important criterion to assess excavation. To treat an exposed pulp, 75% of dentists considered direct capping, 70% refused incomplete excavation fearing caries progression or pulp damage, and 59% reported to prefer more invasive treatment to facilitate restoration longevity. Over 50% recognised an influence of professional regulations on their treatment decisions. There was a moderate correlation between attitudes and behaviour of dentists, with dentists who suspected residual caries to be harmful rejecting incomplete excavation and vice versa. Cluster analysis identified two groups of dentists with opposite attitudes and behaviour, independently from dentist's age or gender. In conclusion, the majority of surveyed dentists was sceptical about leaving caries during excavation and does not practice incomplete caries removal. Therefore, benefits of partial excavation should be highlighted in under- and postgraduate education and regulatory incentives modified to promote minimally invasive techniques.

Micro-hardness and mineral loss of enamel lesions after infiltration with various resins: influence of infiltrant composition and application frequency in vitro

OBJECTIVES

The aim of this in vitro study was to evaluate the influence of infiltrant composition and application frequency on micro-hardness and lesion progression after resin infiltration of artificial enamel lesions.

METHODS

In each of 100 bovine enamel samples, three artificial caries lesions were created (pH=4.95, 50 days). After etching two of the lesions (37% phosphoric acid) specimens were randomly allocated to five infiltrants (four experimental infiltrants with different monomer and solvent compositions and penetration coefficients, and one commercial infiltrant [Icon, DMG]). Lesions were then infiltrated and light-cured, and infiltration repeated afterwards for one of the lesions. Infiltrated samples were cut into halves, with one half being demineralised for further 50 days. Micro-hardness (VHN) and integrated mineral loss (ΔZ) were evaluated at baseline and after second demineralisation. Repeated measures ANOVA and paired t-tests were used to analyse influence of material composition and application frequency on micro-hardness and lesion progression (integrated mineral loss difference ΔΔZ).

RESULTS

Resin infiltration significantly increased micro-hardness and reduced lesion progression compared to untreated artificial lesions (p<0.05, t-test). Neither micro-hardness nor lesion progression were significantly influenced by material composition (p>0.05, ANOVA). In contrast, twice application resulted in significantly increased micro-hardness and demineralisation resistance of infiltrated lesions (p<0.05, ANOVA).

CONCLUSION

Resin infiltration significantly improves micro-hardness and demineralisation resistance of enamel lesions; these effects are significantly enhanced if resins are applied twice. Experimental resins did not outperform the commercial infiltrant.

CLINICAL SIGNIFICANCE

This in vitro study demonstrated that resin infiltration significantly increases both micro-hardness and demineralisation resistance of enamel caries lesions. Twice application of the infiltrant seems to increase these effects. In contrast, the composition of the infiltrant had no significant influence on investigated parameters.

Ex vivo evaluation of caries infiltration after different application times in primary molars

Low viscosity resins (infiltrants) have been shown to penetrate the lesion body of natural caries lesions almost completely in vitro. However, penetration depths (PD) have not been evaluated in vivo. Therefore, the aim of the present study was to evaluate the penetration of an infiltrant into proximal caries lesions in primary molars after different application times using an ex vivo model. 59 proximal lesions from 34 children were randomly allocated to one of the application times and were infiltrated under clinical conditions for 1, 3, or 5 min. After extraction or exfoliation (n = 48), teeth were sectioned perpendicular to their surfaces and lesion depths (LD) as well as lesion areas (LA) were evaluated using polarized light microscopy. PD and penetration areas (PA) were measured on scanning electron microscopic images. Percentage penetration depth (PPD) and percentage penetration area (PPA) were calculated. The mean (±SD) LD and LA were 596 ± 203 µm and 4.03 ± 2.75 × 10(5) µm(2), respectively. PPD ranged from 70 to 80% and PPA from 54 to 60%. Longer application times did not result in significantly deeper or more complete penetration (p > 0.05; ANOVA). In conclusion, proximal caries lesions in primary molars can be infiltrated in vivo to a similar extent as observed previously in vitro. Moreover, 1-min application of the infiltrant led to PD and homogeneity similar to those observed with longer application times up to 5 min.

Relationship of caries and fluorosis in adolescents from high- and low-fluoride areas in Iran

OBJECTIVE

The main aim of the study was to investigate the association between water fluoride concentration and caries as well as fluorosis occurrence in adolescents in Iran. As a secondary aim we studied the relationship between caries and fluorosis occurrence.

BASIC RESEARCH DESIGN

We examined 12-16 year-olds (n = 373) in Orumiyeh [0.3 mgF-/l, low-fluoride (LF)] and Pol Dasht [3.2 mgF-/l, high-fluoride (HF)] for caries-status [D3-Level, Pitts & Fyffe (DMFS)] and fluorosis prevalence [Thylstrup & Fejerskov index (TF)]. Children completed questionnaires about several sociodemographic and oral health related factors of the previous years. To adjust for confounding, we used log risk regression and estimated relative risks (RR) and 95% confidence intervals (CI).

RESULTS

For 12-13 year-olds mean DMFS were 1.9 (sd 2.5) and 1.1 (2.2) in the LF and the HF-areas, respectively. Prevalence of aesthetically relevant fluorosis (TF > 2) was 1% (LF) and 87% (HF). Water fluoride concentration (adjusted for age and SES) was inversely associated with caries-status [RR: 0.7, (CI 0.6-0.8)]. RR for fluorosis was 17 (CI 8-33). In HF-area, caries scores were significantly higher for children with TF > or = 5 on upper central incisors compared with TF < or = 4 (p < 0.05 Mann-Whitney test).

CONCLUSIONS

Caries prevalence in the examined areas in Iran is quite low. Above-optimal water fluoride concentration seems to be effective in reducing caries experience, but increases the occurrence of fluorosis. Severe fluorosis seems to be associated with higher caries occurrence in a high-fluoride area.

Infiltrants inhibit progression of natural caries lesions in vitro

To define the optimized material properties of caries-infiltrating resins (infiltrants), we evaluated the effects of infiltrant composition and penetration coefficient (PC) on the inhibition of the progression of natural approximal caries lesions in vitro. Non-cavitated natural enamel lesions were etched (15% HCl gel) and infiltrated for 5 min with experimental resins varying in PC (cm/sec): PC63, PC185, PC204, and PC391. As a positive control (PosC), lesions were covered with flowable composite resin, whereas untreated lesions served as negative controls (NegC). Specimens were exposed to a demineralizing solution (pH 4.95) for 400 days. Progression of mineral loss was analyzed by transverse wavelength-independent microradiography. Percentage progressions of NegC [median (25th/75th percentile), 24 (10/56)], PC63 [9 (3/39)], and PC185 [12 (9/24)] were significantly higher compared with those of PosC [1 (-8/8)], PC204 [-2 (-4/2)], and PC391 [0 (-5/9)] (p < 0.05). Thus, infiltrants with PC > 200 cm/sec are capable of inhibiting lesion progression.

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.

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% H(3)PO(4)) 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 x 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% x mum) and lesion depths (98 +/- 20 mum) 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.

Sealants in dentistry: outcomes of the ORCA Saturday Afternoon Symposium 2007

Sealants are a successful tool in caries prevention, but their role in preventive strategies after the caries decline has to be discussed. A survey of paediatric departments across Europe revealed that indications for pit and fissure sealants vary considerably, both nationally and internationally. Evidence for effectiveness of sealants in controlling caries in posterior teeth implies that sealants should be an integrated part of management of pit and fissure caries. Still, the indication for occlusal sealants seems to be shifting from primary prevention to a therapeutic decision for caries management of lesions in enamel and the outer part of the dentine. Sealants are also an interesting concept for caries management in approximal surfaces. Clinical trials suggest that novel techniques of sealing or infiltrating approximal lesions show promise. However, approximal sealing techniques are as complex to apply and time-consuming as approximal fillings. The article proposes guidelines for teaching on the use of sealants.

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.