Decision making and management of root caries: A practice-based survey.

OBJECTIVES: With increasing life expectancy and improved preventive measures, teeth are retained longer, leading to a rise in prevalence of root caries lesions (RCL). However, little is known about how dentists manage this condition. The present survey aimed to evaluate the knowledge of Swiss dentists on decision making and management of RCL. METHOD: The survey evaluated dentists' knowledge, clinical routines, and demographics concerning RCL. Dentists were contacted via email and local newsletters, and 383 dentists from 25 (out of 26) cantons responded. Mann-Whitney U test, χ2 test, intraclass correlation coefficients, Spearman correlation and Chi Square were used. RESULTS: The dentists had a mean(SD) working experience of 22.5(12) years. Most dentists correctly classified an inactive (67%) and an active (81%)RCL. Although the inactive lesion did not call for restorative treatments, 61% of the dentist declared they would restore it. From the active lesion,83% would restore it. The invasive treatments leaned toward complete caries excavation with composite resin as preferred restorative material. There were significant correlations between material choice and expected success rates. Among the non-invasive options, oral hygiene instructions and (highly-)fluoridated toothpaste were favored. Most dentists declared having a recall system for such patients, with biannual follow-ups preferred. The dentists' place of education significantly influenced restorative decisions (p < 0.001), while participants' age (≥60years) impacted activity status (p = 0.048) and restorative decisions (p = 0.02). CONCLUSION: Material preferences for non-invasive or invasive management varied greatly and there were minimal differences in the management of inactive or an active RCL. Moreover, diagnosing active lesions appeared easier than diagnosing inactive ones. CLINICAL SIGNIFICANCE: Despite diverse material preferences for (non-)invasive treatments, a strong positive correlation existed between the chosen restorative material and its expected 2-year success rate. Moreover, diagnosing active lesions appeared easier than diagnosing inactive ones. The outcome emphasis the need to align guideline recommendations with their application in private dental practices.

Effects of Hydroxyapatite-Containing Toothpastes on Some Caries-Related Variables: A Randomised Clinical Trial.

OBJECTIVES: This randomised clinical trial was designed and carried out with the aim to evaluate the capacity of fluoride-substituted hydroxyapatite (HAF) toothpaste to modulate oral microflora composition and biofilm acidogenicity in schoolchildren. METHODS: In all, 610 children (4 to 5 and 6 to 7 years) were enrolled. Four toothpastes were randomly administered during 24 months: 2 contained fluoride-substituted hydroxyapatite (HAF1000 and HAF1450; 1000 and 1450 ppmF) and magnesium-, strontium-, and carbonate-substituted hydroxyapatite in a chitosan matrix, and 2 were monofluorophosphate fluoridated toothpastes (F1000 and F1450; 1000 and 1450 ppmF). Caries lesions were assessed by International Caries Detection and Assessment System scores, supragingival plaque was sampled from the approximal sites between primary molars using sterile Gracey curettes for microbiological analysis, and plaque pH curves after sucrose challenge were assessed at baseline and reevaluated after 1 year and after 2 years. The minimum and maximum pH decrease was calculated for caries-free patients and participants with a caries lesion(s) at baseline and at the end of the experimental period (24 months). Differences amongst measurements were analysed with 1-way analysis of variance. RESULTS: During the trial, the minimum pH value increased statistically significantly in all groups; in HAF1000 and HAF1450, the increase was greatest. At the end of trial, in the 2 HAF groups all primary cariogenic bacteria were statistically significantly lower with respect to F groups (P = .03 for Streptococcus mutans and sobrinus, for Lactobacillus casei, and for Lactobacillus fermentum). CONCLUSIONS: The trial provides robust but still inconclusive evidence on the efficacy of HAF toothpastes compared to traditional fluoridated toothpastes to reduce caries risk factors and to prevent caries lesions.

Diagnosing and recording root caries: A survey among Swiss dentists.

OBJECTIVES: Despite the increase in the root caries prevalence, little is still known about how dentists manage this condition. The present study aimed to evaluate the knowledge of dentists on diagnosing and recording root caries lesions (RCL). METHODS: The survey consisted of three domains: (1) dentists' knowledge on diagnosing, recording and managing RCL; (2) information about their current general clinical routines; and (3) their demographics. The four Swiss Universities distributed the survey via e-mail lists for alumni or professionals participating in continuing education. The data was quality checked. Construct validity, internal reliability and intraclass correlation (ICC) were assessed. RESULTS: The survey was answered by 383 dentists from 25(out of 26) cantons [mean(SD) working experience: 22.5(12) years]. The majority replied that they see less than 5 patients with RCL per week, whereas 41 have at least 5 per week, and 40 % (157 dentists) do not distinguish RCL from coronal caries in their patients' medical records. When diagnosing active RCL, tactile sensation was the most predominant criterion (n = 380), whereas color (n = 224) and visual appearance (n = 129) of the lesion were less often selected. The most often chosen risk factors for RCL were poor oral hygiene and presence of biofilm.The responses were significantly influenced by the participants' place of education, their age and working area. CONCLUSION: The present survey highlights the huge diversity in diagnosing, recording and assessing risk factors of RCL. The benefits of an appropriate diagnosis, recording and management of risk factors of RCL should be highlighted in under- and postgraduate dental education. CLINICAL SIGNIFICANCE: A great diversity in diagnosing, recording and assessing risk factors of RCL was observed, which migh strongly impact how dentists manage RCL. The study emphasizes the necessity for intensive efforts to bridge the gap between guideline recommendations and their implementation in private dental practices.

Masking-efficacy and caries arrestment after resin infiltration or fluoridation of initial caries lesions in adolescents during orthodontic treatment-A randomised controlled trial.

OBJECTIVES: The aim of this randomised, controlled, split-mouth trial was to assess the masking results in initial caries lesions (ICL) that were either resin infiltrated or fluoridated during treatment with fixed orthodontic appliances. METHODS: Adolescent patients (age range:12-18years) with fixed orthodontic appliances who had developed ICL [ICDAS 1 or 2 (International Caries Detection and Assessment System)] during orthodontic treatment were consecutively recruited and randomly assigned to either resin infiltration with up to 3 etching procedures (Group:Inf) or to 3-monthly application of a fluoride varnish (Group:FV). Both interventions were performed according to the manufacturer's recommendations. Primary and secondary outcomes (ΔE, ICDAS, DIAGNOdent) included the evaluation of the appearance of the ICL before (T0), 1 week after (T1) treatment and at the last appointment before debonding (T2). RESULTS: Fifteen patients (8females, 7males) with 57ICL were included. Mean (SD) observation time at the last appointment before debonding was 0.5 (0.3) years. At T0 FV and Inf did not differ significantly in ΔE (median ΔE0,FV(25th/75th percentiles):11.6 (8.7/20.3): ΔE0,Inf:15.1 (11.4/19.5); pT0 = 0.135), ICDAS (pT0 = 0.920) and DD (pT0 = 0.367). At T1 and T2 ΔE values (pT1<0.001, pT2<0.001), ICDAS scores (pT1<0.001, pT2<0.001) and DIAGNOdent values (pT1 = <0.001, pT2 = <0.001) for Inf were significantly reduced whereas ΔE values (pT1 = 0.382, pT2 = 0.072) and ICDAS scores (pT1 = 0.268, pT2<0.001) for FV remained unchanged. CONCLUSIONS: Resin infiltration effectively masked ICL during treatment with fixed orthodontic appliances both immediately after application and at the last appointment before debonding. Furthermore, the visual appearance of fluoridated lesions was not as satisfactory as that of the infiltrated ones at both T1 and T2. CLINICAL SIGNIFICANCE: Resin infiltration effectively masked ICL during treatment with fixed orthodontic appliances both immediately after application and at the last appointment before debonding. Furthermore, the visual appearance of fluoridated lesions was not as satisfactory as that of the infiltrated ones immediately after first application as well as half a year after application. TRIAL REGISTRATION: German Clinical Trials Register (DRKS-ID: DRKS00011797).

Aesthetic caries infiltration - Long-term masking efficacy after 6 years.

OBJECTIVES: This study aimed to evaluate the masking efficacy of caries infiltration technique of initial caries lesions (ICL) six years after debonding and single treatment. METHODS: In 10 adolescents, 74 ICL (ICDAS 2) in 74 teeth were treated by resin infiltration (Icon, DMG) at a mean (SD) of 1.2 (1.2) months after bracket removal. The etching procedure was performed up to 3 times. Standardized digital images were taken before treatment (T0), seven days (T7) and 6 years (T2190) after treatment. Outcomes included the evaluation of the color differences between carious and healthy enamel at T0, T7 and T2190 by quantitative colorimetric analysis (ΔE), ICDAS scores, quantitative light-induced fluorescence (QLF; ΔF,ΔQ,WS Area) and qualitative visual evaluation (5-point Likert-scale [deteriorated (1), unchanged (2), improved, but not satisfying (3), improved and no further treatment required (4), completely masked (5)). RESULTS: The median color difference ΔΕ0 (25th/75th percentiles) at T0 was 10.3 (8.56/13.0). At T7 a significant decrease was observed (ΔΕ7=3.7 (2.0/5.8); p<0.001; Friedmann-test; ICDAS p<0.001; Chi-square test). No significant changes based on ΔΕ (p=0.972; Friedmann-test) and ICDAS grading (p=0.511, chi-square test) were observed between T7 and T2190 (ΔΕ2190=2.9 (1.8/4.2)). Furthermore, at T2190 four experienced dentists classified 50% and 37% of the lesions as "improved and no further treatment required" and "completely masked", respectively (Fleiss kappa: T2190: 0.782 (substantial agreement)). CONCLUSION: Aesthetic caries infiltration can effectively mask post-orthodontic initial caries lesions for at least 6 years. These results for most of the teeth could not only be observed by quantitative but also by qualitative analysis. CLINICAL SIGNIFICANCE: Resin infiltration efficaciously masks post-orthodontic initial carious lesions. The optical improvement can be observed directly after treatment and remains stable for at least six years.

Design, development and validation of a questionnaire to assess dentists' knowledge and experience in diagnosing, recording, and managing root caries.

OBJECTIVES: The prevalence of root caries is increasing globally, especially in the elderly population, and even though the number of patients with root caries lesions is augmenting, there are still many discrepancies in how dentists manage this condition. The present study aimed to develop and validate a questionnaire to evaluate how dentists diagnose, record and manage root caries lesions, and to verify the validity and reliability of this questionnaire. MATERIALS AND METHODS: An expert panel developed a self-administered questionnaire survey with three domains: (1) dentists' knowledge on diagnosis, recording, and managing root caries; (2) information about their current general clinical routines; (3) their demographics. The original English [E] version was translated into three different languages (French [F], German [G], Italian [I]), and subsequently back-translated into English by independent dentists. For the validation, 82 dentists (20-22 for each of the translated versions) accepted to answer the questionnaire at two different time-points (with 1-week interval). The data was quality checked. Construct validity, internal reliability, and intra-class correlation (ICC) were assessed. RESULTS: Seventy-seven dentists completed the questionnaire twice [E: 17; F: 19; G: 19; I: 22]. The mean ICC (standard deviation) was 0.98(0.03) for E, 0.90(0.12) for F, 0.98 (0.04) for G, and 0.98 (0.01) for I. Overall, the test-retest reliability was excellent (mean ICC (SD): 0.96 (0.08)). Furthermore, the questionnaire demonstrated good internal reliability (inter-observer reliability; Fleiss kappa: overall:0.27(fair); E:0.30 (fair); F: 0.33(fair); G: 0.33(fair); I: 0.89 (almost perfect)). CONCLUSION: The questionnaire was validated and is suitable to be used in the four languages to assess the knowledge of dentists on diagnosing, recording and managing root caries. CLINICAL SIGNIFICANCE: The present questionnaire was validated and seems to be a good tool to evaluate how dentists diagnose, record, and manage root caries lesions both in its original (English) and its translated (French, German, and Italian) versions.

Short-term efficacy of caries resin infiltration during treatment with orthodontic fixed appliances. A randomized controlled trial.

OBJECTIVES: Objective of this trial was to assess the masking results in initial caries lesions (ICL) that were resin infiltrated during fixed orthodontic treatment in comparison to contralateral teeth that were fluoridated only. TRIAL DESIGN: A randomized, controlled, split-mouth trial. METHODS: Adolescent patients (age range: 12-18 years) with fixed orthodontic appliances who had developed ICL [ICDAS 1 or 2 (International Caries Detection and Assessment System)] during orthodontic treatment were consecutively recruited and randomly assigned to either resin infiltration (Icon) with up to 3 etching procedures (Inf) or to a fluoride varnish (Tiefenfluorid) (FV). Both interventions were performed according to the manufacturer's recommendations. Outcome assessors were blinded to the applied intervention. Primary and secondary outcomes included the evaluation of the appearance of the ICL before (T0) and 1 week after (T1) treatment by digital photographs (ΔE), laser fluorescence readings (DD), and ICDAS scores. BLINDING: Due to the treatment nature neither the operators nor the patients could be blinded. However, outcome assessors and the statistician were blinded. RESULTS: Fifteen patients (9 female) with 60 ICL were included (mean age: 14.6 years). At baseline FV and Inf did not differ significantly in ΔE (median ΔE0,T (25th/75th percentiles):10.7(9.1/20.9): ΔE0,I:13.4(10.3/18.5); P = 0.469), DD (P = 0.867) and ICDAS (P = 0.521). One-week after treatment (T1) ΔE values (P < 0.001), DD values (P < 0.001), and ICDAS scores (P = 0.014) for Inf were significantly reduced, whereas ΔE values (P = 0.125) and ICDAS scores (P = 0.073) for FV remained unchanged. LIMITATION: Natural remineralizing in the standard interventional control group cannot be observed yet, since up to 6 months are needed to naturally remineralize ICL. CONCLUSIONS: Based on our short-term data, resin infiltration effectively masked ICL during treatment with fixed orthodontic appliances. Fluoridation was not able to immediately improve the visual appearance of ICL. Further longer-term assessment should focus not only on the aesthetic outcome, but also on the caries inhibitory effect of resin infiltration during treatment with fixed orthodontic appliances. TRIAL REGISTRATION: German Clinical Trials Register (DRKS-ID: DRKS00011797).

Improved Surface Layer Erosion of Pit and Fissure Caries Lesions in Preparation for Resin Infiltration.

The penetration of a low-viscosity resin (infiltrant) into caries lesions depends on the erosion of the relatively impermeable surface layer (SL) that covers the lesion body. The present study aimed to evaluate the effect of different abrasive pretreatments on erosion of the SL and on penetration of an infiltrant into occlusal caries lesions, simultaneously. Sixty extracted human molars showing International Caries Detection and Assessment System (ICDAS-2) lesions were randomly allocated to 5 groups. A small area of each lesion was covered with resin before etching. Twelve lesions each were etched with either 15% HCl-gel (H120) or 37% H3PO4-gel (P120) for 120 s. Furthermore, the standard 15% HCl-gel or either one of two experimental etchants (HCl-gel or H3PO4-gel, each including abrasives) were applied for either 120 s or 30 s using a brush (surface pressure 150 g) (H30B, P120BA, H30BA). After rinsing and drying, all lesions were infiltrated for 180 s (Icon; DMG). From each tooth sections were prepared and visualized using confocal microscopy. SL of unetched areas and the lesion depth were 33 (23/51) µm and 537 (274/876) µm, respectively, both not differing significantly between groups. H120, H30B, and H30BA showed significantly higher SL reduction compared with P120 or P120BA, but only for H30BA SL was eroded almost completely (p < 0.05; Mann-Whitney test). Compared to other groups, occlusal lesions were significantly more infiltrated in H30BA (p < 0.05; Mann-Whitney test). HCl-gel including abrasives that was rubbed onto the enamel surface with a brush seems to be most effective to erode SLs of caries lesion situated in fissures and enable an almost complete subsequent resin infiltration.

Posterior ceramic versus metal restorations: A systematic review and meta-analysis.

OBJECTIVES: The goal of this systemic review and meta-analysis was to evaluate the longevity of indirect adhesively-luted ceramic compared to conventionally cemented metal single tooth restorations. DATA: Randomized controlled trials (RCT) investigating indirect adhesively-luted ceramic restorations compared to metal or metal-based cemented restorations in permanent posterior teeth. SOURCES: Three electronic databases (PubMed, CENTRAL (Cochrane) and Embase) were screened. No language or time restrictions were applied. Study selection, data extraction and quality assessment were done in duplicate. Risk of Bias and level of evidence was graded using Risk of Bias 2.0 tool and Grade Profiler 3.6. RESULTS: A total of 3056 articles were found by electronic databases. Finally, four RCTs were selected. Overall, 443 restorations of which 212 were adhesively-luted ceramic restorations and 231 conventionally cemented metal restorations have been placed in 314 patients (age: 22-72 years). The highest annual failure rates were found for ceramic restorations ranging from 2.1% to 5.6%. Lower annual failure rates were found for metal (gold) restorations ranging from 0% to 2.1%. Meta-analysis could be performed for adhesively-luted ceramic vs. conventionally cemented metal restorations. Conventionally cemented metal restoration showed a significantly lower failure rate than adhesively-luted ceramic ones (visual-tactile assessment: Risk Ratio (RR)[95%CI]=0.31[0.16,0.57], low level of evidence). Furthermore, all studies showed a high risk of bias. CONCLUSION: Conventionally cemented metal restorations revealed significantly lower failure rates compared to adhesively-luted ceramic ones, although the selected sample was small and with medium follow-up periods with high risks of bias.

Efficacy of nano-hydroxyapatite on caries prevention-a systematic review and meta-analysis.

INTRODUCTION/OBJECTIVES: The review systematically explored in vivo or in situ studies investigating the efficacy of nano-hydroxyapatite (nHA) to reduce initiation of or to remineralize initial caries lesions. DATA: Prospective controlled (non-)randomized clinical trials investigating the efficacy of a nHA compared to any other (placebo) treatment or untreated/standard control. SOURCES: Three electronic databases (Central Cochrane, PubMed-MEDLINE, Ovid EMBASE) were screened. Outcomes were, e.g., ICDAS score, laser fluorescence, enamel remineralization rate, mineral loss, and lesion depth. No language or time restrictions were applied. Risk of bias and level of evidence were graded using the Risk of Bias 2.0 tool and GRADE profiler. STUDY SELECTION/RESULTS: Five in vivo (and 5 in situ) studies with at least 633 teeth (1031 specimens) being assessed in more than 420 (95) patients were included. No meta-analysis could be performed for in vivo studies due to the high heterogeneity of the study designs and the variety of outcomes. In situ studies indicate that under demineralization conditions, NaF was able to hinder demineralization, whereas nHA did not; simultaneously, nHA did not differ from the fluoride-free control. In contrast, under remineralizing conditions, nHA and NaF show the same remineralizing potential. However, the level of evidence was very low. Furthermore, six studies showed a high risk of bias, and six studies were funded/published by the manufacturers of the tested products. CONCLUSION: The low number of clinical studies, the relatively short follow-up periods, the high risks of bias, and the limiting grade of evidence do not allow for conclusive evidence on the efficacy of nHA. CLINICAL RELEVANCE: No conclusive evidence on the efficacy of nHA could be obtained based on the low number of clinical studies, the relatively short follow-up periods, the high risks of bias, the limiting grade of evidence, and study conditions that do not reflect the everyday conditions.

Long-term Survival of Adhesively Luted Post-endodontic Restorations.

INTRODUCTION: The objective of this prospective clinical study was to investigate survival for endodontically treated teeth restored with adhesively luted prefabricated dentinlike or rigid posts. METHODS: Data were recorded for glass-fiber posts (GFPs) and compared with historical controls evaluating glass-fiber (GFP I) and titanium posts (TPs) for 128 patients. Three groups were defined based on the type of post system used: group 1, GFP I (n = 41); group 2, GFP II (n = 41); and group 3, TP (n = 46). Posts were adhesively luted with self-adhesive resin, adhesive composite core buildups were performed, and all teeth were restored with full-coverage restorations. The primary end point was restoration survival at recall. Outcome was assessed after 6, 12, 24 and up to 178 months clinically and radiographically. Data were analyzed by the Kaplan-Meier log-rank test and Cox regression analysis. RESULTS: After up to 178 months of observation, 26 restorations failed (GFP I: 10, GFP II: 9, and TP: 7) and 49 (GFP I: 18, GFP II: 12, and TP: 19) were in situ. Cumulative survival probabilities were 57.1% for the GFP I, 56.5% for the GFP II, and 71.8% for the TP groups. In bivariate Cox regression, the factors tooth type and grade of abrasion were significantly assfociated with failure. In multivariate Cox regression, none of the investigated factors were significantly associated with failure. The post system had no significant impact on tooth survival (P > .05). CONCLUSIONS: Comparing GFPs and TPs, the post system had no impact on tooth survival up to 15 years. This study indicates that the effect size of post material on survival is low.

Efficacy of HAF toothpastes in primary and permanent dentitions. A 2-years triple-blind RCT.

OBJECTIVES: The aim of this RCT was to compare the caries preventive efficacy and the slowing down of previous caries lesions of toothpastes containing fluoride biomimetic hydroxyapatite (HA) complex compared to sodium monofluorophosphate fluoridated toothpastes in Italian schoolchildren. To validate this hypothesis a triple-blind randomized clinical trial was designed. METHODS: In total 610 children (4-5 and 6-7 years) were enrolled. Four toothpastes, two containing fluoride-substituted hydroxyapatite (HAF) (1000 and 1450 ppmF) and magnesium-, strontium-, carbonate-substituted hydroxyapatite, in a chitosan matrix and two Mono fluoridated toothpastes (1000 and 1450 ppmF) were randomly administered during 24 months to two groups with younger children (Gyoung) and to two groups with older children (Gold), those containing 1450 ppmF. ICDAS was used to score lesions as initial (up to score 2), moderate (scores 3-4) and severe (scores 5-6). The children were instructed to brush for two minutes three times/day. Caries examination was repeated at 12 and 24 months. The efficacy of the treatment was assessed by calculating the reduction in Risk Ratio (RR) and the number needed to treat (NNT). Results; Overall, 518 patients (Gyoung = 268; Gold = 250) concluded the trial. The drop-rate was 11.84% for Gyoung and 17.22% for Gold. The caries increment at 24-month evaluation was statistically lower in the primary dentition in the HAF arms compared to the traditional fluoridated arms (0.18 vs 0.27 p = 0.04 in Gyoung and 0.16 vs 0.30 p = 0.01 in Gold for severe lesions). In the permanent dentition (Gold), caries increase was also statistically lower in the HAF arm, both for initial and severe lesions (0.09 vs 0.17 p = 0.02 and 0.18 vs 0.28 p = 0.01, respectively). In primary dentition, children receiving HAF Toothpaste had a RR of 39% (Gyoung) and 38% (Gold), compared to children receiving traditional Toothpastes. The RR in the permanent dentition was 29% in children treated with HAF toothpaste. Conclusions; The use of toothpastes containing biomimetic hydroxyapatite and fluoride reduces caries increment in children over a period of 2 years more than traditional fluoridated toothpastes.

Increasing dental zirconia micro-retentive aspect through ultra-short pulsed laser microstructuring: study on flexural strength and crystal phase characterization.

OBJECTIVES: Although ultra-short pulsed laser (USPL) microstructuring has previously improved zirconia bond-strength, it is yet unclear how different laser-machined surface microstructures and patterns may influence the material's mechanical properties. Therefore, the aim of this study was to assess the flexural strength of zirconia after different USPL settings creating three different geometrical patterns with structures in micrometer scale. METHODS: One hundred sixty zirconia bars (3Y-TZP, 21 × 4 × 2.1 mm) were prepared and randomly divided into five groups (n = 32): no surface treatment (negative control-NC); sandblasting with Al2O3 (SB); and three laser groups irradiated with USPL (Nd:YVO4/1064 nm/2-34 J/cm2/12 ps): crossed-lines (LC), random-hatching (LR), and parallel-waves (LW). Bars were subjected to a four-point flexural test (1 mm/min) and crystal phase content changes were identified by X-ray diffraction. Surface roughness and topography were analyzed through 3D-laser-profilometry and SEM. Data were analyzed with parametric tests for roughness and Weibull for flexural strength (α = 5%). RESULTS: LR (Mean[95%CI]: 852.0 MPa, [809.2-894.7]) was the only group that did not show a significantly different flexural strength than NC (819.8 MPa, [796.6-842.9]), (p > 0.05). All laser groups exhibited higher Weibull moduli than NC and SB, indicating higher reliability and homogeneity of the strength data. An increase of monoclinic phase peak was only observed for SB. CONCLUSION: In conclusion, USPL created predictable, homogeneous, highly reproducible, and accurate surface microstructures on zirconia ceramic. The laser-settings of random-hatching (12 ps pulses) increased 3Y-TZP average surface roughness similarly to SB, while not causing deleterious crystal phase transformation or loss of flexural strength of the material. Furthermore, it has increased the Weibull modulus and consequently material's reliability. CLINICAL SIGNIFICANCE: Picosecond laser microstructuring (LR conditions) of 3Y-TZP ceramic does not decrease its flexural strength, while increasing materials realiability and creating highly reproducible and accurate microstructures. These features may be of interest both for improving clinical survival of zirconia restorations as well as enhancing longevity of zirconia implants.

Effects of the association of high fluoride- and calcium-containing caries-preventive agents with regular or high fluoride toothpaste on enamel: an in vitro study.

OBJECTIVES: The aim of this in vitro study was to compare the caries-preventive effect of various high fluoride- and calcium-containing caries-preventive agents (> 22.000 ppm F- [ppm]) in adjunct to use of regular (1450 ppm) or high (5000 ppm) fluoride toothpaste on sound as well as demineralized enamel. MATERIALS AND METHODS: Bovine enamel specimens (n = 276; 5 mm × 3.5 mm × 3 mm) having one sound surface [ST] and one artificial caries lesion [DT] were randomly allocated to 12 groups. Interventions before pH-cycling were no intervention ([SC1/SC5]), application of varnishes/solutions containing NaF (22,600 ppm; Duraphat [NaF1/NaF5]); NaF + tricalcium phosphate (22,600 ppm; Clinpro White Varnish [TCP1/TCP5]); NaF + CPP-ACP (22,600 ppm; MI Varnish [CPP1/CPP5]); silver diammine fluoride (35,400 ppm; Cariestop 30%[SDF1/SDF5]); and NaF + calcium fluoride (45,200 ppm; Biophat[CaF1/CaF5]). During pH-cycling (28 days, 6 × 120 min demineralization/day) half of the specimens in each group were brushed (10 s; 2 × /day) with either 1,450 (NaF; named, e.g., TCP1) or 5,000 ppm (NaF; e.g., TCP5) dentifrice slurry. Differences in integrated mineral loss (∆∆Z) and lesion depth (∆LD) were calculated between values after initial demineralization and after pH-cycling using transversal microradiography. RESULTS: After pH-cycling, SC1/SC5 showed significantly increased ∆ZDT/LDDT values, indicating further demineralization (p < 0.05; paired t-test). Decreased ∆ZDT values, indicating non-significant remineralization, could only be observed in CaF1/CaF5 (p > 0.05; paired t-test). Additional use of all varnishes/solutions significantly decreased ∆∆ZDT/∆∆ZST and ∆LDDT/∆LDST compared to SC1/SC5 (p < 0.05;ANCOVA). Between 1450 and 5000 ppm dentifrices, a significant difference in ∆∆ZDT/∆∆ZST and ∆LDDT/∆LDST could only be observed for SC1/SC5 (p < 0.05; ANCOVA). CONCLUSION: Under the conditions chosen, all fluoride varnishes/solutions significantly reduced demineralization. Furthermore, a significant dose-response characteristic for fluoride varnishes could be revealed. However, no additional benefit could be observed, when varnishes were combined with high fluoride instead of regular fluoride dentifrices. CLINICAL RELEVANCE: For children and adolescents with high caries risks varnishes containing more than 22,600 ppm should be further investigated, as they offered higher caries-preventive effects in vitro. Furthermore, there seems to be no difference in the demineralization-inhibitory capacity of fluoride varnishes when used in combination with either standard or highly fluoridated dentifrices.

Internal morphology of 101 mandibular canines of a Swiss-German population by means of micro-CT: An ex vivo study.

The aim of this study was to investigate the root canal system morphology by means of a root canal configuration (RCC) classification described with a four-digit system, the physiological foramen geometry and accessory canal frequency and morphology, of 101 mandibular canines (MaCa) of a Swiss-German population by means of micro-computed tomography. Micro-CT examination of the MaCa was performed and the obtained images analyzed with a 3D imaging software. In single-rooted MaCas, the most frequently observed RCCs were 1-1-1/1 (74.5%) and 1-1-1/2 (14.3%). Seven other RCCs were less frequently observed with a frequency from 4.1 to 1.0%. One physiological foramen was observed in 80.6% of the MaCas, two in 16.3%, three in 1.0% and four in 2.0%. Accessory and connecting canals were apparent only in the middle and apical root thirds. Two-rooted MaCas occurred less frequently (n = 3). When one physiological foramen was present, the mean size of the narrow and wide diameters were 0.28 mm (± 0.07) and 0.40 mm (± 0.11), while the distance between physiological and anatomical foramen was 0.45 mm (± 0.17). MaCas are predominantly single-rooted teeth with a 1-1-1/1 or 1-1-1/2 RCC. Most MaCas had one physiological foramen with an oval shape.

Influence of embedding media on the accuracy of working length determination by means of apex locator: an ex vivo study.

The aim of this research was to determine ex vivo the influence on accuracy of five different embedding media, for investigative and educational purposes, and one electronic apex locator. 110 human extracted mature roots of permanent single-rooted human teeth were used. The roots were embedded in alginate, stick sponge, 2% agar-agar and 6% and 12% gelatin. The actual working length to the physiological foramen was determined under a stereo-microscope (16 ×) and the electronic working lengths with the Elements Diagnostic Unit and a K-file ISO 10. The accuracy ranges of the accumulated measurements, when allowing a ± 0.5 mm tolerance, went from 98.2% (6% and 12% gelatin), 93.7% (alginate), 92.8% (2% agar-agar) to 91.7% (sponge). The exact measurements at the physiological foramen ranged from 80.0% (6% gelatin), 76.5% (2% agar-agar), 71.8% (12% gelatin), 68.2% (alginate) to 64.5% (sponge). Although relatively seldom (n = 24), measurements with deviations of more than ± 0.5 mm were also observed; thus, the accuracy of the working length determination results per se can be considered as clinically acceptable. The results of this research allow a recommendation of the investigated embedding media for electronic working length determination models for educational and research purposes in endodontics.

Long-term costs of post-restorations: 7-year practice-based results from Germany.

OBJECTIVES: We evaluated the initial and follow-up treatment costs of different post-restorations in a practice-based German healthcare setting. METHODS: A total of 139 incisors, canines, or premolars received post-restorations placed by eight general dental practitioners in Germany, and were followed over a mean ± SD 7.1 ± 4.5 years. Preformed metal (MP, n = 68), glass-fiber (GF, n = 28), or cast post-and-core buildups (MC, n = 23) had been used to retain crowns or bridge anchors. Preformed metal and glass-fiber had also been used to retain directly built up post-retained composite restorations (PC, n = 20). Material and treatment costs for the initial post-restorations as well as restorative, endodontic, or surgical re-treatments were estimated from a public-payer-perspective in Germany. Associations between total and annualized total costs and covariates were assessed using generalized linear modeling. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00012938). RESULTS: MC showed highest initial treatment costs (557.23 Euro), but the least re-treatments (6/23, 26%), while PC showed lowest initial costs (203.52 Euro) but the most re-treatments (11/20, 55%). Costs for MP/GF post-crowns were initially similarly costly (496.47/496.87 Euro), and both also showed similar re-treatments (35%/36%). The overall annual failure rate was 5.2% (MC: 3.5%, MP: 4.6%, GF: 5.3%, PC: 10.3%). Including costs for the resulting re-treatments, mean total costs were 591.66 Euro (MC), 548.31 Euro (MP), 526.37 Euro (GF), and 361.81 Euro (PC). Annualized total costs were 171.36 Euro (MC), 141.75 Euro (MP), 146.12 Euro (GF), and 135.65 Euro (PC). Total and annualized total costs were highest for MC, with PC being the significantly less costly option (p < 0.001). CONCLUSIONS: Within German healthcare, both initial and follow-up costs for post-restorations were considerable. Saving costs initially may, at least partially, be offset by more complications long-term. CLINICAL RELEVANCE: Dentists need to be aware that the placement of posts is not only initially costly but also comes with significant long-term costs for treating occurring complications. This should be communicated with patients and considered during treatment planning.

Longevity and Risk Factors of Post Restorations after up to 15 Years: A Practice-based Study.

INTRODUCTION: The aims of this multicenter, practice-based cohort study were to evaluate the success and survival of endodontically treated teeth with post restorations (ETT+Ps) and to analyze factors associated with the longevity of ETT+Ps. METHODS: Eight general dental practitioners each placed up to 27 ETT+Ps without any restriction to post materials or dimensions. Only incisors, canines, and premolars were included. At the last follow-up visit, ETT+Ps were considered as successful if the post and the initially placed definitive restoration were sufficient, whereas ETT+Ps were considered as survived if the post was still in function. Multilevel Cox proportional hazards models were used to evaluate the association between a range of predictors and time until no success and no survival. RESULTS: Overall, 195 endodontic posts in 195 patients were followed up for a mean (95% confidence interval) of 91 (81-101) months; the longest follow-up was 15 years. Of these, 122 ETT+Ps were considered successful (estimated success time = 110 [101-120] months), and 152 ETT+Ps survived [estimated survival time = 133 [124-141] months). Regarding the categories of success and survival, the annual failure rates were 6.0% and 3.3%, respectively. Recementation of old (telescopic) crowns after placing new posts was the only significant predictor for decreased time until failure for both success and survival analyses. By excluding recemented restorations, annual failure rates decreased to 3.5% and 2.1%, respectively. CONCLUSIONS: For EET+Ps placed in a private practice setting, high success and survival rates were observed. If old (telescopic) crowns were recemented after new posts were placed, the high risk of subsequent failure should be considered and communicated with patients.

Do bleaching gels affect the stability of the masking and caries-arresting effects of caries infiltration-in vitro.

OBJECTIVES: The aim of this study was to evaluate the influence of different bleaching gels on the masking and caries-arresting effects of infiltrated and non-infiltrated stained artificial enamel caries lesions. MATERIALS AND METHODS: Bovine enamel specimens (n = 240) with each two sound areas (SI and SC) and each two lesions (DI and DC) were infiltrated (DI and SI), stained (1:1 red wine-coffee mixture,70 days), and randomly distributed in six groups to be bleached with the following materials: 6%HP (HP-6), 16%CP (CP-16), 35%HP (HP-35), 40%HP (HP-40), and no bleaching (NBl,NBl-NBr). Subsequently, specimens were pH-cycled (28 days, 6 × 60 min demineralization/day) and all groups except NBl-NBr were brushed with toothpaste slurry (1.100 ppm, 2×/day, 10 s). Differences in colorimetric values (ΔL, ΔE) and integrated mineral loss (ΔΔZ) between baseline, infiltration, staining, bleaching, and pH cycling were calculated using photographic and transversal microradiographic images. RESULTS: At baseline, significant visible color differences between DI and SC were observed (ΔEbaseline = 12.2; p < 0.001; ANCOVA). After infiltration, these differences decreased significantly (ΔEinfiltration = 3.8; p < 0.001). Staining decreased and bleaching increased ΔL values significantly (p ≤ 0.001). No significant difference in ΔΔE was observed between before staining and after bleaching (ΔEbleaching = 4.3; p = 0.308) and between the bleaching agents (p = 1.000; ANCOVA). pH-cycling did not affect colorimetric values (ΔEpH-cycling = 4.0; p = 1.000). For DI, no significant change in ΔZ during in vitro period was observed (p ≥ 0.063; paired t test). CONCLUSIONS: Under the conditions chosen, the tested materials could satisfactorily bleach infiltrated and non-infiltrated stained enamel. Furthermore, bleaching did not affect the caries-arresting effect of the infiltration. CLINICAL RELEVANCE: The present study indicates that bleaching is a viable way to satisfactorily recover the appearance of discolored sound enamel and infiltrated lesions.

Analysis of relative bacterial activity and lactate dehydrogenase gene expression of caries-associated bacteria in a site-specific natural biofilm: an ex vivo study.

OBJECTIVES: Detecting bacterial activity is considered a promising approach to monitor shifts from symbiosis to dysbiosis in oral microbiome. The present study aimed at investigating both the relative bacterial activity and the lactate dehydrogenase (ldh) gene expression of caries-associated bacteria in a site-specific natural biofilm. MATERIAL AND METHODS: Sixty subjects (age, mean ± SE: 30.1 ± 1.4) were allocated to two groups: caries-free subjects (CF) or caries-active subjects (CA). CF presented one sound surface (CFS, n = 30). CA presented two donor sites: a cavitated caries lesion (CAC, n = 30) and a sound reference surface (CAS, n = 30). Real-time quantitative PCR (q-PCR) on species or genus level and total bacteria was performed targeting the 16S gene, the 16S rRNA, the ldh gene, and the ldh mRNA (increasing 16S ribosomal RNA copy numbers can function as an indicator of increased energy metabolism). As the 16S rRNA abundance represents the number of ribosomes, while the 16S gene abundance represents the number of genomes, the quotient of the relative abundances functions as a measure for the relative bacterial activity (%). RESULTS: Both lactobacilli and S. mutans showed the highest relative bacterial activity in CAC ((mean ± SE) 218 ± 60% and 61 ± 16%, respectively) and the lowest values for both sound reference surfaces (69 ± 48%; 8 ± 3%). Significant differences were found between CAC and CAS as well as between CAC and CFS for both lactobacilli and S. mutans (p < 0.05). The ldh gene expression of lactobacilli and S. mutans only showed moderate values in CAC (1.90E+03 ± 2.11E+03; 2.08E+04 ± 4.44E+04 transcripts/µl) and CFS (2.04E+03 ± 2.74E+03; 8.16E+03 ± 6.64E+03 transcripts/µl); consequently no significant differences were detected. CONCLUSION AND CLINICAL RELEVANCE: Caries-associated bacteria (lactobacilli and S. mutans) showed the highest relative bacterial activity in plaque of cavitated lesions, the lowest in sound surfaces, allowing the detection of a significant activity shift in health and disease for caries-active patients. However, no significant differences in ldh gene expression could be determined.