Longevity of immediate rehabilitation with direct metal-wire reinforced composite fixed partial dentures.

OBJECTIVES This study aimed to analyze the longevity of direct metal-wire reinforced composite fixed partial dentures (MRC-FPD) and factors influencing their survival and success. METHODS Within one private practice 513 MRC-FPD were directly applied. The preparation of a proximal cavity in abutment teeth was not limited. MRC-FPD were reinforced by one to three metal-wires. At the last follow-up MRC-FPD were considered successful, if they were still in function without any need of therapy. MRC-FPD were considered as survived, if they were repaired or replaced. Multi-level Cox proportional hazard models were used to evaluate the association between clinical factors and time. RESULTS Mean follow-up period (range) was 59(2-249) months. Seventy-three bridges did not survive (cumulative survival rate(CSR):86%) and further 129 bridges had received a restorative follow-up treatment (CSR:61%). AFR was 2.2% for survival and 8.6% for success. In multivariate analysis MRC-FPD with> 1 wire showed a up to 2.3x higher failure rate than MRC-FPD with one wire(p ≤ 0.023). Dentist's experience in designing MRC-FDP (p ≤ 0.017), patient's caries risk (p ≤ 0.040) and bruxism (p = 0.033) significantly influenced the failure rate: the more experience, the lower caries risk and bruxism, the lower the failure rate. SIGNIFICANCE For directly prepared metal-wire reinforced composite bridges high survival and moderate success rates were observed. MRC-FPD might, thus, be an immediate, short- and medium-term solution for replacing missing teeth. However, several factors on the levels of practice (dentist's experience in designing MRC-FDP), patient (bruxism, caries risk) and restoration (number of wires) were identified as significant predictors for the failure rate. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00021576)

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

Root canal morphology of the mandibular second premolar: a systematic review and meta- analysis

Background: The aim of this paper was to systematically review the root canal configuration (RCC) and morphology literature of the mandibular second premolar (Mn2P). Methods: Systematic research of five electronic databases was performed to identify published literature concerning the root canal configuration (RCC) of the Mn2P up through July 2020. Studies were selected according to predefined search terms and keywords inclusion criteria: “root canal configuration”, “root canal system”, “root canal morphology”, “mandibular second premolar”, “mandibular premolars”, “morphology” and “anatomy”. Further possible studies were identified by cross-referencing and screening the bibliographies of the selected articles. Results: From 1622 retrieved studies, 44 studies investigating the internal morphology of 17,839 Mn2Ps were included. Most examined Mn2Ps were single-rooted (89.5–100%); two-rooted (0.1–8%) and three-rooted (0.1–3.5%) Mn2Ps at lower frequency. Most frequent RCCs reported were 1–1–1/1 (55.3–99.6%) followed by 1–1–2/2 (0.5–57%) and 2–2–2/2 (0.6–18%). The meta-analysis of seven studies demonstrated that a significantly higher number of RCC type 1–2–1/1 (OR [95%CI] = 2.05 [1.27, 3.33]) and 2–2–2/2 (OR [95%CI] = 2.32 [0.65, 8.63]) were observed in male than in female patients. Conclusions: Different RCC research methods have been reported. Whereas clearing and radiographs were com- monly used in the past, CBCT has been prevalent in recent years. A globally high frequency of a 1–1–1/1 RCC in the Mn2P has been reported. Nevertheless, the probability that different, more complicated RCCs can appear in Mn2Ps should not be underestimated and, thus, should be taken into consideration when making decisions during an endo- dontic treatment

Systematic review and meta-analysis on physical barriers to prevent root dentin demineralization.

The present review systematically analyzed in vitro and in situ studies investigating physical diffusion barriers (sealants, desensitizer or adhesives) to prevent the development or the progression of root (dentin) demineralization. Three electronic databases (PubMed-Medline, CENTRAL, Ovid-EMBASE) were screened for studies from 1946 to 2022. Cross-referencing was used to identify further articles. Article selection and data abstraction were done in duplicate. Languages were not restricted. The type of outcome was not restricted, and their mean differences (MD) were calculated using fixed- or random-effects models. Risk of Bias was graded using Risk of Bias 2.0 tool. From 171 eligible studies, 34 were selected for full-text analysis evaluating 69 different materials, and 17 studies-still evaluating 36 different materials-were included (3 in situ and 14 in vitro). Ten studies evaluated desensitizers; 8 adhesives; and 1 infiltration. Meta-analyses were possible for all 17 studies. Meta-analyses revealed that lesion depth after no treatment was significantly higher than after the application of single-step adhesives (MD[95%CI] = - 49.82[- 69.34; - 30.30]) and multi-step adhesives (MD[95%CI]=-60.09 [-92.65, -27.54]). No significant differences in the lesion depth increase between single- and multi-step adhesives could be observed (MD[95%CI]=30.13 [-21.14, 81.39]). Furthermore, compared to no treatment the increase of the lesion depth was significantly hampered using desensitizers (MD[95%CI] = - 38.02[- 51.74; - 24.31]). Furthermore, the included studies presented unclear or high risk. A physical diffusion barrier can significantly hamper the increase of lesion depth under cariogenic conditions. Furthermore, multi-step adhesives seem not to be more effective than single-step adhesives. However, this conclusion is based on only few in vitro and in situ studies

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

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

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

Bond strength and marginal adaptation of resin composites and correlations with clinical results.

OBJECTIVES Due to innumerable confounding factors and a high number of types and brands of dental restorative materials, the clinical performance of restorative materials are sought predicted by various in vitro tests. However, only few such tests have been found to correlate well with clinical findings. Thus, the present study determined the in vitro dentin bond strength and marginal adaptation of Class II restorations and correlated the results to their clinical outcomes. METHODS Dentin bond strength (µTBS and µSBS) and marginal gap formation of Class II restorations (replica technique and SEM) were measured after 24 h and 6 m water storage using eight combinations of adhesive and resin composite. Clinical outcomes (mean survival time, Hazard Ratio, annual failure rate; n = 10.695) were gained from a data set of a retrospective multicenter study of direct restorations. RESULTS Significant differences were found for dentin bond strength and marginal gap formation between the restorative material groups, and negative effects of long-term storage were observed. µTBS correlated significantly with certain clinical outcomes of Class I restorations, while µSBS correlated with certain clinical outcomes of Class II, III, IV and V restorations. Marginal gap formation in enamel and number of paramarginal fractures correlated with certain clinical outcomes of Class II restorations. SIGNIFICANCE Using the same restorative materials in vitro as in vivo, gave significant, but weak correlations between in vitro bond strength or marginal adaptation and clinical outcomes, lending support to the use of in vitro tests in early stages of material selection

Risk factors for failure of class V restorations of carious cervical lesions in general dental practices.

OBJECTIVES The aim of this retrospective, non-interventional, multi-center, practice-based study was to analyze factors influencing the survival of restorative treatments of one- and two-surface active cervical (root) caries lesions (CCLs). METHODS Records from patients who visited five private practices regularly were searched for the presence of active one- and two-surface CCLs. Data from 1167 patients with 2070 CCLs being detected at least 6 months before the last recall visit were recorded. Kaplan-Meier-analyses were used to analyze time-to-failure. Cox proportional hazards models were used to evaluate the association between clinical factors and time until failure. RESULTS Within 120 months [mean (SD) follow-up period:50 (40) months] 219 failures could be observed. Median survival time was 120 months. The AFR was 1.82% for one-surface restorations (CCL1) and 3.25% for two-surface restorations (CCL2). In multivariate Cox regression two-surface cervical restorations showed 1.75 times higher failure rates than one-surface cervical restoration. Furthermore, CCL being checked up more than twice a year showed significantly higher failure rates than restorations being checked up less than twice a year (p < 0.001). CONCLUSION Low failure rates could be found for restorative treatment strategies of one- as well as for two-surface CCLs. CLINICAL SIGNIFICANCE Restorative treatment of CCLs is a viable way to manage one-surface CCLs. However, the proximal extension of the CCL significantly shortens the longevity of the restoration. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00012510)