Ion release, biocompatibility, and bioactivity of resin-modified calcium hydroxide cavity liners.

BACKGROUND: The placement of liners near the pulp area is essential for therapeutic effects and maintaining pulp health while stimulating the formation of tertiary dentin. This in vitro study aimed to evaluate the calcium release, pH, biocompatibility, solubility, and bioactivity of three resin-modified calcium hydroxide cavity liners. METHODS: The disc specimens of each cavity liner were prepared using polyethylene molds of 7 mm in diameter and 2 mm in height (n = 10). Three light-cure liners evaluated include Ultra-Blend Plus (UB), Base-it (BI), and Master Dent (MD). The samples were then immersed in flasks containing 10 mL of distilled water. Calcium ion release, pH, and solubility were evaluated in two weeks of incubation. The cytotoxicity of extracts adjacent to the specimens was evaluated by MTT assay using NIH/3T3 cells after 1, 3, and 7 days of incubation. The ability to induce the nucleation of calcium phosphates (CaPs) after 28-day immersion in a simulated body fluid was investigated by SEM-EDX analysis. Statistical analysis was performed using ANOVA, Kruskal-Wallis, and repeated measures tests at the significant level of 0.05. RESULTS: There was a significant difference in the release of calcium ions among the three liners investigated on days 1, 7, and 14 (p < 0.05). UB liners exhibited a significantly higher amount of calcium release than the other two liners, followed by BI, and MD. On day 1, there was no significant difference in the average pH among the three liners. However, after day 7, the MD liner showed a significant decrease in pH compared to the other two liners. BI liner demonstrated the highest level of biocompatibility, followed by the MD and UB liners. UB showed a high calcium release, solubility with no alkalizing activity, and the formation of more mature Ca-rich apatite deposits than the other two liners. CONCLUSION: Based on the results of this study, the cavity liner material's performance is material dependent. It can impact ion release, biocompatibility, and bioactivity which are important factors to consider in clinical practice. Further studies are needed to investigate the long-term effects of different liner materials on oral tissues.

Does the liner material influence pulpal vitality in deep carious cavities submitted to selective caries removal? A network meta-analysis review.

OBJECTIVES: To evaluate whether the restorative material in direct contact with the dentin influences pulp vitality in primary and permanent teeth with deep carious lesions restored after selective caries removal (SCR). MATERIAL AND METHODS: Systematic searches of databases MEDLINE via PubMed, Scopus and ISI Web of Science were performed for primary and permanent teeth. Inclusion criteria were applied for title and abstract reading of databases search results. After full texts review of included studies, those that did not meet exclusion criteria were excluded from meta-analysis. RESULTS: For meta-analysis, 2 studies were included for permanent teeth and 6 for primary teeth. The failure events reported were meta-analyzed using two statistical methods: standard pairwise meta-analysis (SPMA) and network meta-analysis (NMA). The SPMA identified similar failure occurrence of restorations performed with calcium hydroxide (CH) and other liner materials (RR 0.84, 95% CI 0.41, 1.74; p = 0.64), no significant difference between the use of alternative liners or CH regardless deciduous or permanent teeth (RR 0.79, 95% CI 0.36, 1.71; p = 0.55) and similar risk of failing at different follow-ups for all liner materials tested (RR 0.77, 95% CI 0.35, 1.70; p = 0.52). Probabilistic analysis indicated GIC as liner material with the highest probability of clinical success (SUCRA = 72.76%), and CH ranked as the worst liner material (SUCRA = 21.81%). CONCLUSION: Pulpal vitality was not affected by material used as liner after selective caries removal in deep carious cavities. CLINICAL RELEVANCE: Current clinical evidence supports the weak recommendation to not use calcium hydroxide as liner after SCR.

Chapter 9.3: Current Concepts of Caries Removal in Daily Practice.

Although the discussion about the amount of carious dentin to be removed during cavity preparation is quite old, concepts for caries removal have evolved and changed considerably over the last decades. The antiquate understanding that it was necessary to eliminate the microbial contamination of a cavity before placing the restoration was replaced by the current knowledge that maintaining contaminated dentin beneath restorations is inevitable and is not associated with treatment failure. This chapter brings together the body of evidence behind carious dentin removal to indicate a conservative treatment, aiming to preserve both tooth vitality and structure. Studies that evaluated the effects of sealing contaminated dentin are described, which are focused on different outcomes, such as microbiological counts, clinical characteristics, laboratory analysis, and radiographic findings. Long-term studies and randomized clinical trials also support the current recommendations. After addressing the available literature on this topic, this chapter concludes that (1) the amount of carious dentin to be removed should be defined by lesion depth; (2) sealing and/or selective caries removal to firm dentin is recommended for the management of shallow and moderate lesions; (3) the selective caries removal to soft dentin in a single session is indicated for deep caries lesions aiming to preserve tooth vitality; and (4) the use of a cavity liner after selective caries removal seems to be an unnecessary clinical step.

Marginal and Internal Adaptation of Cervical Restorations Using Direct, Direct-indirect, and Indirect Techniques.

OBJECTIVE: This study aimed to evaluate the external and internal adaptations of cervical restorations using different restorative techniques. METHODS: Forty extracted and intact human premolars received standardized cervical preparations to simulate non-carious cervical lesions. The teeth were randomly divided into four groups (n=10) according to the restorative technique: D, direct composite restoration without a base (Palfique LX5, Tokuyama Dental Corp Inc, Tokyo, Japan); DB, direct composite restoration with a flowable composite liner (Estelite Flow Quick -High Flow, Tokuyama Dental Corp Inc); DI, direct-indirect composite restoration bonded with flowable composite; and I, indirect restoration bonded with flowable composite. Marginal adaptation of the restorations was observed in different segments of the margins using a scanning electron microscope. Analyses of internal adaptation were performed using micro-computed tomography. The Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis of the data (α=5%). RESULTS: No significant differences were found in the marginal adaptation of the groups (p>0.05), although a significantly higher percentage of continuous margin was found in the proximal segment than in the cervical segment (p<0.05). No significant differences were detected between the groups in terms of internal adaptation (p>0.05). CONCLUSION: All the restorative techniques evaluated for the restoration of cervical lesions performed similarly in terms of marginal and internal adaptation.

Five-year clinical performance of two fluoride-releasing giomer resin materials in occlusal restorations.

OBJECTIVE: To evaluate and compare the clinical performance of two nano-hybrid giomer restorative composite materials after 5 years. MATERIALS AND METHODS: Forty-four pairs of restorations (total n = 88) of a flowable giomer (Beautifil Flow Plus F00; Shofu Inc., Kyoto, Japan) and a conventional nano-hybrid giomer restorative material (Beautifil II; Shofu Inc.) were placed in Class I cavities after the application of a dentin adhesive (FL-Bond II; Shofu Inc.) and a flowable liner (Beautifil Flow Plus F03; Shofu Inc). After 5 years, 32 pairs of restorations were assessed using the modified United States Public Health Service criteria. Both tested materials were compared using Fisher's exact test and each tested clinical criterion for each material was analyzed separately with respect to different follow-up periods using Friedman's test (a = 0.05). RESULTS: None of the restorations showed complete retention loss, post-operative sensitivity, secondary caries or color change. There were no significant changes to any of the clinical criteria for each material during the 5-year evaluation period (p > 0.05) and no significant differences between the two materials in all clinical parameters after 5 years (p > 0.05). CONCLUSIONS: Five-year clinical performance of both two nano-hybrid giomer restorative materials was comparably acceptable and not significantly different for any of the parameters evaluated. CLINICAL SIGNIFICANCE: Nano-hybrid giomer-based materials are clinically acceptable for the restoration of occlusal cavities as they demonstrate excellent performance after 5 years.

White-opaque flowable composite liner as a depth marker in composite restorations prevents tooth substance loss in filling removal: a randomized double-blinded in vitro study.

OBJECTIVES: Removal of esthetic restorations leads to loss of tooth structure and the extent of the loss is difficult to estimate due to exact-shade matching. This randomized double-blinded in vitro study aimed examining the influence of a white-opaque flowable composite depth marker as an optical removal aid for tooth substance preservation and shortened restoration removal time. MATERIALS AND METHODS: Class II cavities (n = 100) in extracted healthy mandibular molars (n = 50, two runs) were prepared, filled, and the restoration removed. Tooth weight and volume (before and after) and removal time were measured and remnants visually documented. An optimal tooth shade-matched flowable composite liner was used as control. RESULTS: Tooth structure loss was significantly lower using a white-opaque liner. Mean values for volume/weight loss were 0.037 ± 0.030 g and 0.016 ± 0.005 cm3 (p < 0.01) for white-opaque liner; 0.067 ± 0.000 g and 0.028 ± 0.003 cm3 (p < 0.01) for tooth-colored composite. Removal time and number of pulp chamber perforations showed no significant differences (p = 0.80). CONCLUSIONS: Within the limitations of this randomized double-blinded in vitro study, the use of a white-opaque flowable liner as a depth marker may provide the practitioner a visual aid in the replacement of a composite restoration and may protect against tooth structure loss. CLINICAL RELEVANCE: When restoration replacement is indicated, removal of esthetic restorations often causes tooth structure loss due to difficult optical color matching. Using a white-opaque flowable liner as a depth marker clinically aids in restoration removal and protects against tooth structure loss.

Is fluoride varnish safe?: Validating the safety of fluoride varnish.

BACKGROUND: Fluoride varnish is widely used in dentistry as a caries preventive measure with recommendations for its use even in infants. In addition, nondental providers are also applying varnish on children's teeth in various settings. However, there are questions from these nondental providers as to the safety of fluoride varnish. METHODS: To evaluate and describe the adverse events (AEs) related to fluoride varnish, the US Food and Drug Administration's Manufacturer and User Facility Device Experience database was used. AEs reported for the dental product code for "varnish, cavity," "varnish," and "fluoride" were evaluated. The identified AEs were then reviewed and categorized using appropriate key words for the various signs and symptoms, outcomes, and treatment. RESULTS: Over the 10-year period, only 65 AEs were reported for fluoride varnish products. Swelling (33.8%); burning, itching, or soreness (23.1%); and rash (16.9%) were the most common signs and symptoms reported. The most common site reported was the lips (27.7%). The most common outcome was that the patient was taken to the hospital (18.5%) or emergency department (15.4%). No deaths were reported. The patients were treated primarily using diphenhydramine (Benadryl, Johnson & Johnson Consumer) (26.1%), followed by an epinephrine autoinjector (EpiPen, Mylan) and other forms of epinephrine (15.4%), and prednisolone (9.2%). In 16.9% of the cases with AEs there was a history of allergies. The rate of AEs is estimated to be between 0.099 and 0.105 per million for fluoride varnish. A concern is the likelihood of underreporting AEs in the Manufacturer and User Facility Device Experience database. CONCLUSIONS: Given the widespread use of fluoride varnish in the United States, the number of AEs reported to the US Food and Drug Administration were few. Thus fluoride varnish can be considered a safe dental product. PRACTICAL IMPLICATIONS: Provides data on the safety of fluoride varnish that can be used by the dental profession to allay concerns by nondental providers and patients on this important caries preventive measure.

Probing the hierarchy of evidence to identify the best strategy for placing class II dental composite restorations using current materials.

OBJECTIVE: The objective of this review is to present a synopsis of the existing clinical and in vitro evidence regarding placement of direct class II restorations with dental composites of varying viscosities, focusing on the marginal integrity achievable. OVERVIEW: The literature on class II composites placed with various techniques was searched through PubMed, Scopus, and the citations of identified articles, focusing on aspects related to adaptation and clinical performance. Studies comparing layering of conventional composite to layering with a flowable liner, including the "snow plow technique," use of warmed composite, flowable bulk-fill liners with a conventional composite capping layer, and bulk-fill restorative in a single or incremental fill (including placement with sonic energy and dual-curing) CONCLUSIONS: In vitro and clinical evidence does not support any one specific method or material type for achieving optimal performance when restoring class II cavity preparations with current dental composites. CLINICAL SIGNIFICANCE: Although there are many available placement methods and types of composite materials on the market for use in class II restorations, the reasonable success presented in the clinical and laboratory literature for the various approaches suggests that the most important factor for achieving success is likely careful and proper placement and light-curing technique, independent of the approach.

Class II resin composite restorations-tunnel vs. box-only in vitro and in vivo.

PURPOSE: In a combined in vitro/in vivo approach, tunnel vs. box-only resin composite restorations should be evaluated using thermomechanical loading (TML) in vitro and a restrospective clinical trial in vivo. MATERIALS AND METHODS: For the in vitro part, box-only and tunnel cavities were prepared in 32 extracted human third molars under simulated intraoral conditions in a phantom head. Specimens were randomly assigned to four groups (n = 8; 16 box-only/16 tunnel) and received bonded resin composite restorations with Amelogen Plus (box A/tunnel A) or lining with Ultraseal and Amelogen plus (box B/tunnel B) both bonded using PQ1 (all Ultradent). Specimens were subjected to a standardized aging protocol, 1-year water storage (WS) followed by TML (100,000 × 50 N; 2500 × + 5/+ 55 °C). Initially and after aging, marginal qualities were evaluated using replicas at × 200 magnification (SEM). For the corresponding in vivo observational study, 229 patients received 673 proximal resin composite restorations. From 371 tunnel restorations, 205 cavities were filled without flowable lining (tunnel A), and 166 tunnels were restored using UltraSeal as lining (tunnel B). A total of 302 teeth received conventional box-only fillings. Restorations were examined according to modified USPHS criteria during routine recalls up to 5 years of clinical service. RESULTS: In vitro, all initial results showed 100% gap-free margins when a flowable lining was used. Tunnels without lining exhibited some proximal shortcomings already before TML and even more pronounced after TML (p < 0.05). After TML, percentages of gap-free margins dropped to 87-90% in enamel with lining and 70-79% without lining (p < 0.05). In vivo, annual failure rates for box-only were 2.2%, for tunnel A 6.1%, and for tunnel B 1.8%, respectively (p < 0.05). Tunnels had significantly more sufficient proximal contact points than box-only restorations (p < 0.05). Flowable lining was highly beneficial for clinical outcome of tunnel-restorations (p < 0.05). CONCLUSIONS: With a flowable lining, tunnel restorations proved to be a good alternative to box-only resin composite restorations. CLINICAL RELEVANCE: Class II tunnel restorations showed to be a viable alternative for box-only restorations, however, only when flowable resin composite was used as adaptation promotor for areas being difficult to access.

The influence of a liner on deep bulk-fill restorations: Randomized clinical trial.

OBJECTIVE: The aim of this study was to evaluate the influence of a liner on the clinical performance of deep posterior restorations performed with bulk-fill composite. METHODS: 30 subjects received two restorations on deep preparations in posterior teeth, without pulpal exposure, after selective carious-tissue removal in one-stage. The internal walls reached the inner quarter of dentin, but with a radiographically detectable zone of firm dentin remaining. The pulpal protection using a layer of glass ionomer composite liner (Ionoseal, Voco) was applied in just one preparation. The adhesive system Futurabond U (Voco) was applied in all preparations, which were restored with the bulk-fill pure Ormocer nanohybrid composite (Admira Fusion Xtra - Voco), in up to 4 mm thick increments. All restorations were evaluated using the FDI criteria after 7 days, 6, 12 and 24 months postoperatively. RESULTS: After 24-months, 25 patients attended the recall and 50 restorations were evaluated. The Fisher's statistical analysis (5%) showed no difference between the techniques for the esthetic, functional and biological properties. No postoperative sensitivity was reported for both groups. CONCLUSION: The application of a liner did not influence the clinical performance of deep restorations with bulk-fill Ormocer composite. CLINICAL RELEVANCE: The application of a liner with a GIC-based material did not have a significant effect on the clinical performance of bulk-fill restorations and seems to be unnecessary for the material tested.

Mineral exchange within restorative materials following incomplete carious lesion removal using 3D non-destructive XMT subtraction methodology.

OBJECTIVES: The objective of this study was to quantify the changes in mineral and selected element concentrations within residual carious dentine and restorative materials following incomplete carious lesion removal (ICLR) using different cavity liners, with non-destructive subtraction 3D-X-ray Microtomography (XMT, QMUL, London, UK). MATERIALS AND METHODS: A total of 126 extracted teeth with deep dental caries were assessed using International Caries Risk and Assessment (ICDAS). Eight teeth were subsequently selected after radiographic evaluation. Each lesion was removed, leaving a thin layer of leathery dentine at the deepest part of cavity. Different cavity lining materials were placed; Mineral Trioxide Aggregate (MTA), calcium hydroxide, (Ca(OH)2), resin-based material (RBM). For each, the restorative material was an encapsulated glass ionomer (GIC) and the control group had a GIC restoration alone. Each tooth was immediately placed in Simulated Body Fluid (SBF). All samples were then imaged using XMT at baseline, and three weeks after treament. The XMT images were then subtracted to show the mineral concentration changes three weeks after treatment. RESULTS: There were significant increases in mineral concentrations within the residual demineralised dentine in individual teeth treated with Ca(OH)2, MTA, RBM, and GIC following immersion in SBF for three weeks. GIC group without any liners showed the greatest increase in mineral concentration, followed by MTA and Ca(OH)2. CONCLUSION: Mineral changes in demineralised dentine and within restorative materials are quantifiable using non-destructive 3D-XMT subtraction methodology. This laboratory study suggested that calcium, phosphate and strontium ion-exchange occurs with GIC, MTA and Ca(OH)2 in deep dentinal lesions following ICLR. CLINICAL RELEVANCE: In clinical practice, incomplete carious lesion removal could be performed to avoid the dental pulp exposure. 3D non-destructive XMT subtraction methodology in a laboratory setting is advantageous to provide evidence for different restorative materials on deep carious lesions prior to clinical investigations.

A Quality Improvement Project to Optimize Fluoride Varnish Use in a Pediatric Outpatient Clinic with Multiple Resident Providers.

The pediatric clinic at Kapi'olani Medical Center provides dental varnish to prevent decay. A chart review (conducted August 1-31, 2017) revealed that only 49.6% of eligible children received varnish. Among those who did not receive varnish, no explanation was provided in 83.9% of the charts. This quality improvement project was designed to increase delivery and documentation of dental varnish. The participants were 14-15 pediatric and psychiatry residents (11 present for all cycles). Cycle 1 interventions were a 5-minute resident educational session on the importance and process of fluoride varnish, and visual reminders on all order entry computers in the clinic. Cycle 2 intervention consisted of a prompt added to the clinic's default well child visit templates requiring notation of whether varnish was given and a reason if not. Data for cycle 2 was collected over 6 weeks as some residents chose to use their own templates, serving as an unplanned comparison group. Application of varnish increased to 77.7% (P < .001) after cycle 1, and was statistically unchanged for cycle 2 (74% (P = .24)). Documentation of reason for lack of varnish was missing in 80% (P = .59) after cycle 1 and 17 % (P < .001) after cycle 2 (with prompt). In the cycle 2 comparison group using their own templates, the varnish application rate was 71% (P < .001) with no explanation for lack of varnish 84% of the time (P = .95). Brief educational interventions may result in increased use of fluoride varnish in resident-based clinics. Task based prompts or stop measures in electronic medical record templates can improve documentation, which can inform efforts to improve varnish application.

Improving oral health through dental fluoride varnish application in a primary care paediatric practice.

Dental caries affect 97% of people during their lifetime. A total of 59% of children aged 12-19 will have at least one documented cavity. The American Academy of Pediatrics recommends fluoridated toothpaste to all children starting at tooth eruption, regardless of caries risk. Besides, fluoride varnish is recommended for all children every 3-6 months from tooth emergence until they have a permanent dental home. This project aimed to increase oral fluoride varnish application for children starting at 6 months or the time of tooth eruption up to 3 years of age by at least 50% over 18 months. The stakeholders identified were physicians, nurses, medical assistants and the health information team. We obtained baseline data about oral health screening and fluoride varnish from both the clinic sites. The quality improvement (QI) project was based on Plan-Do-Study-Act (PDSA) cycles with a 6-month gap in-between the three cycles. For the first cycle, all medical staff members participated in 2-hour knowledge and skills training on dental caries and current recommendations on fluoride varnish. PDSA cycle 2 involved having automatic reminders for providers in electronic medical records. PDSA cycle 3 planned to have automatic fluoride orders for the recommended age groups. The QI team analysed the results after every 6 months, and improvements were made based on the input from data and medical staff. The number of patients who had fluoride varnish applied increased from 14% (n=50) to 55% at the end of PDSA cycle 3. Administration of the varnish did not affect the flow of the patients in busy primary care practice. The rate of improvement was across all the age groups, providers and in both clinical sites. It is possible to adhere to the oral fluoride varnish guidelines in a busy primary care practice, which may help benefit young children who are at risk for caries.

A randomized clinical trial of cavity liners after selective caries removal: one-year follow-up.

INTRODUCTION: Alternatives for the treatment of caries disease, such as minimally invasive approaches, have been developed in recent years. OBJECTIVE: To carry out clinical and radiographic evaluations of three cavity liners after selective caries removal. METHODOLOGY: Thirty-six primary molars with deep occlusal caries lesions without pulp involvement (from children of both genders, aged between 5 and 8 years) were randomly divided into the following groups: calcium hydroxide cement (CHC) group; mineral trioxide aggregate (MTA) group and Portland cement with added zirconium oxide (PCZ) group. The following-up period was 6- and 12-month. The clinical and radiographic success rates were evaluated through chi-square test. The radiographic measurements were compared by ANOVA followed by Tukey's test (p<0.05). RESULTS: Thirty-six patients were included, but thirty-four returned for 12-month follow-up. The overall success rate of the therapy for the three groups was 94.11% and no statistically significant differences occurred in the comparison among groups (p>0.05). Nineteen radiographs were selected to measure the dentin barrier thickness. The intragroup comparison presented a statistically significant increase of the dentin barrier for all groups, at 12-month follow-up. However, the MTA group showed increase of the dentin barrier, over time, 6- to 12-month follow-up. The intergroup comparison revealed no statistically significant differences (p>0.05). CONCLUSION: The clinical and radiographic data showed that all cavity liners provided effective treatment of primary teeth after selective caries removal.

Effect of Different Liners on Pulpal Outcome after Partial Caries Removal: A Preliminary 12 Months Randomised Controlled Trial.

AIM: The aim of this double-blinded parallel randomised controlled trial was to compare the effect of different liners on 12-month pulp health outcomes after partial caries removal (PCR) with composite restorations in permanent molars. METHODS: The study was registered at clinicaltrials.gov with registration No. NCT0328695 and conducted in the Department of Conservative dentistry and Endodontics, Post Graduate Institute of Dental Sciences Rohtak with no external financial support. One hundred and ninety-eight participants (116 males, 82 females and age 14-54 years) with vital permanent mature mandibular molars having deep caries involving two-thirds or more of dentin were randomised to calcium hydroxide (CH), resin-modified GIC (RMGIC) and no liner (DC) groups after PCR. After a follow-up time of 12 months, success was defined as positive response to pulp sensibility and absence of periapical alterations. RESULTS: Categorical variables were compared using chi-square test. Two analytical approaches were used, such as intention-to-treat and per-protocol approach. Success rates in per-protocol approach were 96.8, 96.5, and 94.6% for CH, RMGIC and DC groups, respectively with no significant difference between 3 groups (p = 0.811). None of the baseline variables had any significant influence on the treatment success. CONCLUSION: Partial caries excavation has a high success rate to treat deep carious lesions in permanent teeth after 12 months of follow-up, indicating that the retention of carious dentin does not interfere with pulp vitality or restoration survival. Also, the success of the treatment is independent of the lining material used over the demineralized dentin.

Dental cavity liners for Class I and Class II resin-based composite restorations.

BACKGROUND: Resin-based composite (RBC) is currently accepted as a viable material for the restoration of caries for posterior permanent teeth requiring surgical treatment. Despite the fact that the thermal conductivity of the RBC restorative material closely approximates that of natural tooth structure, postoperative hypersensitivity is sometimes still an issue. Dental cavity liners have historically been used to protect the pulp from the toxic effects of some dental restorative materials and to prevent the pain of thermal conductivity by placing an insulating layer between restorative material and the remaining tooth structure. This is an update of the Cochrane Review first published in 2016. OBJECTIVES: The objective of this review was to assess the effects of using dental cavity liners in the placement of Class I and Class II resin-based composite posterior restorations in permanent teeth in children and adults. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 12 November 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 10) in the Cochrane Library (searched 12 November 2018), MEDLINE Ovid (1946 to 12 November 2018), Embase Ovid (1980 to 12 November 2018) and LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; 1982 to 12 November 2018). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. SELECTION CRITERIA: We included randomized controlled trials assessing the effects of the use of liners under Class I and Class II posterior resin-based composite restorations in permanent teeth (in both adults and children). We included both parallel and split-mouth designs. DATA COLLECTION AND ANALYSIS: We utilized standard methodological procedures prescribed by Cochrane for data collection and analysis. Two review authors screened the search results and assessed the eligibility of studies for inclusion against the review inclusion criteria. We conducted risk of bias assessments and data extraction independently and in duplicate. Where information was unclear we contacted study authors for clarification. MAIN RESULTS: Eight studies, recruiting over 700 participants, compared the use of dental cavity liners to no liners for Class I and Class II resin-based composite restorations.Seven studies evaluated postoperative hypersensitivity measured by various methods. All studies were at unclear or high risk of bias. There was inconsistent evidence regarding postoperative hypersensitivity (either measured using cold response or patient-reported), with a benefit shown at some, but not all, time points (low-quality evidence).Four trials measured restoration longevity. Two of the studies were judged to be at high risk and two at unclear risk of bias. No difference in restoration failure rates were shown at 1 year follow-up, with no failures reported in either group for three of the four studies; the fourth study had a risk ratio (RR) 1.00 (95% confidence interval (CI) 0.07 to 15.00) (low-quality evidence). Three studies evaluated restoration longevity at 2 years follow-up and, again, no failures were shown in either group.No adverse events were reported in any of the included studies. AUTHORS' CONCLUSIONS: There is inconsistent, low-quality evidence regarding the difference in postoperative hypersensitivity subsequent to placing a dental cavity liner under Class I and Class II posterior resin-based composite restorations in permanent posterior teeth in adults or children 15 years or older. Furthermore, no evidence was found to demonstrate a difference in the longevity of restorations placed with or without dental cavity liners.

In vitro evaluation of apical microleakage in retrofillings with different resection angles.

The aim of this study was to evaluate the effect of flowable composite or glass ionomer liners on the shrinkage stress of a restorative composite resin. Fifteen previously sandblasted metal boxes were attached to a universal mechanical testing machine (INSTRON 1011, Instron Corporation). Five of these boxes were filled with Filtek Z350 XT (FXT) Universal Restorative A2 (3M ESPE) (Group 1 or Control). Two further groups of 5 boxes were prepared by interposing a layer of Vitrebond Light Cure Glass Ionomer 3M ESPE (VGI) (Group 2 or G.I.) or Filtek Z350 XT Flowable Restorative A2 3M ESPE (FFR) (Group 3 or Flowable) between the box and the composite resin, completing with the same volume of composite as in Group 1. Upon activating lightcuring, the filled boxes mounted on the testing machine were videoed for 60 seconds (40 s photoactivation and 20 s postcuring), timed with a digital chronometer. Force values were recorded in newtons and converted into stress according to contact surface. Stress values were recorded every 10 s. Results were analyzed using repeated measures ANOVA. Mean and standard deviation in kPa (stress) recorded for each group were: Control group: 126.2 (30.8); G.I.: 48.4 (18); Flowable: 27.9 (19.5). Statistical analysis showed significant differences between the control group and the rest (p<0.01), with no significant difference between groups with glass ionomer liners and flowable resin liners (G.I. and Flowable). Under the experimental conditions of this study, it can be concluded that polymerization shrinkage stress can be reduced by the presence of a liner between the preparation and the restorative material.

El objetivo de este trabajo fue evaluar el efecto de la colocación de una capa de Composite flow o Ionómero vítreo sobre la tensión de contracción de un composite para restauración. Se utilizaron 15 cajas metálicas previamente arenadas y conectadas a la máquina universal para ensayos mecánicos (INSTRON 1011, Instron Corporation). Cinco de estas cajas (G1) se rellenaron con Filtek Z350 XT (FXT) Universal Restorative A2 3M ESPE. Al iniciar la activación de la unidad de curado se comenzaba a registrar con una cámara de video y un cronómetro digital desde el comienzo de la activación de la lámpara hasta 60 s después, registrando los valores post curado durante 20 s. Los valores de fuerza generados por la polimerización fueron registrados en newton de cada 10 s para los 15 ensayos. Los valores fueron convertidos en tensión de contracción según la superficie de contacto. Se realizaron además dos grupos de cajas (5 en cada una) en los cuales se colocaron una capa inicial de Vitrebond Light Cure Glass Ionomer 3M ESPE (VGI) (G2 o IV) y Filtek Z350 XT Flowable Restorative A2 3M ESPE (FFR) (G3 o Flow) y se completó con el mismo volumen de composite de las del GI. Los resultados obtenidos fueron analizados por medio de ANOVA para mediciones repetidas. La media y la desviación estándar en kPa (tensión o estrés de contracción) registrado para cada grupo fueron: Grupo control: 126.2 (30.8); IV: 48.4(18); Flow: 27.9(19.5). El análisis estadístico mostró diferencias estadística mente significativas entre el grupo control y el resto (p=0.00), pero no hubo diferencias significativas entre la presencia de Ionómero vítreo o Composite Flow (IV y Flow). En las condiciones experimentales de este trabajo puede concluirse que la tensión de contracción generada durante la polimerización puede ser disminuida por la presencia de algún material interpuesto entre la preparación y el composite restaurador.

Positive influence of simvastatin used as adjuvant agent for cavity lining.

OBJECTIVES: To assess the biological, antimicrobial, and mechanical effects of the treatment of deep dentin with simvastatin (SV) before application of a glass-ionomer cement (GIC). MATERIALS AND METHODS: Dentin discs were adapted to artificial pulp chambers and SV (2.5 or 1.0 mg/mL) was applied to the occlusal surface, either previously conditioned or not with EDTA (±EDTA). The extracts (culture medium + SV that diffused through dentin) was obtained and then applied to cultured odontoblast-like MDPC-23 cells. Cell viability, alkaline phosphatase (ALP) activity, and mineralization nodule (MN) deposition were evaluated. Untreated discs were used as control. The antibacterial activity of SV (2.5 or 1.0 mg/mL) against Streptococcus mutans and Lactobacillus acidophilus, as well as the bond strength of GIC to dentin in the presence of SV 2.5 mg/mL (±EDTA) were also assessed. The data were analyzed by ANOVA/Tukey tests (α = 5%). RESULTS: EDTA + SV 2.5 mg/mL significantly enhanced the ALP activity and MN deposition in comparison with the control, without changing in the cell viability (p < 0.05). The association EDTA + SV 2.5 mg/mL + GIC determined the highest ALP and MN values (p < 0.05). SV presented intense antimicrobial activity, and the EDTA dentin conditioning followed by SV application increased bond strength values compared with SV treatment alone (p < 0.05). CONCLUSION: SV presents antimicrobial activity and diffuses across conditioned dentin to biostimulate odontoblast-like pulp cells. CLINICAL SIGNIFICANCE: The use of SV as adjuvant agent for indirect pulp capping may biostimulate pulp cells thus preserving vitality and function of the pulp-dentin complex.