Effect of Different Liners on Fracture Resistance of Premolars Restored with Conventional and Short Fiber-Reinforced Composite Resins.

PURPOSE: To see whether applying four different liners under short fiber-reinforced composite (SFRC), everX Posterior, compared to conventional composite resin, Z250, affected their strengthening property in premolar MOD cavities. MATERIALS AND METHODS: Mesio-occluso-distal (MOD) cavities were prepared in 120 sound maxillary premolars divided into 10 groups (n = 12) in terms of two composite resin types and 4 liners or no liner. For each composite resin, in 5 groups no liner, resin-modified glass ionomer (RMGI), conventional flowable composite (COFL), self-adhesive flowable composite resin (SAFL), and self-adhesive resin cement (SARC) were applied prior to restoring incrementally. After water storage and thermocycling, static fracture resistance was tested. Data (in Newtons) were analyzed using two-way ANOVA (α = 0.05). RESULTS: Fracture resistance was significantly affected by composite resin type (p = 0.02), but not by the liner (p > 0.05). The interaction of the two factors was not statistically significant (p > 0.05). SFRC exhibited higher fracture strength (1470 ± 200 N) compared to conventional composite resin (1350 ± 290), irrespective of the application of liners. Application of SARC and SAFL liners led to a higher number of restorable fractures for both composite resins. CONCLUSIONS: The four liners can be used without interfering with the higher efficacy of SFRC, compared to conventional composite resins, to improve the fracture strength of premolar MOD cavities.

Compressive Strength of a Glass Ionomer Cement Under the Influence of Varnish Protection and Dietary Fluids / Resistencia a la compresión de un cemento de ionómero de vidrio bajo la influencia de la protección del barniz y diversos productos alimenticios

RESUMEN El objetivo de este estudio fue evaluar la resistencia a la compresión de un cemento de ionómero de vidrio (GIC) bajo la influencia de la protección del barniz y alimentos. Ochenta muestras cilíndricas de GIC fueron realizadas y se distribuyeron en cuatro grupos (G1, G2, G3, G4) de acuerdo con el alimento. Cada grupo se sub-dividió además en A y B, de acuerdo con la presencia o ausencia de protección de barniz. Las ocho muestras de cada subgrupo se almacenaron en agua destilada durante 30 días y recibieron los siguientes tratamientos durante 14 días: G2A: protección del barniz e inmersión en gaseosas, G2B: sin barniz e inmersión en gaseosas, G3A: protección del barniz e inmersión en jugo de naranja, G3B: sin protección de barniz e inmersión en jugo de naranja, G4A: protección de barniz e inmersión en yogurt, G4B: sin protección de barniz e inmersión en yogur. El procedimiento de inmersión se realizó tres veces al día, durante 15 minutos por 14 días. Las muestras del Subgrupo G1A (con barniz) y G1B (sin barniz) se usaron como controles y se almacenaron en agua destilada. Las muestras se sometieron a una prueba de resistencia a la compresión después del período de inmersión. Los resultados se analizaron usando ANOVA 2, prueba de Tukey (5%) y T de Student (5%). No hubo diferencias significativas entre los subgrupos, a excepción del subgrupo con protección de barniz e inmersión en jugo de naranja, que mostró una resistencia a la compresión GIC reducida.

ABSTRACT The objective of this study was to evaluate the compressive strength of a glass ionomer cement (GIC) under the influence of varnish protection and dietary fluids. Eighty cylindrical test specimens were made from GIC and distributed into four groups (G1, G2, G3, G4) according to the dietary fluid. Each group was further divided into subgroups A and B according to the presence or absence of varnish protection. The eight subgroup samples were stored in distilled water for 30 days and received the following treatments for 14 days: G2A: varnish protection and immersion in soft drink, G2B: no varnish protection and immersion in soft drink, G3A: varnish protection and immersion in orange juice, G3B: no varnish protection and immersion in orange juice, G4A: varnish protection and immersion in yogurt, G4B: no varnish protection and immersion in yogurt. The immersion procedure was performed three times a day, for 15 minutes at a time, for a total of 14 days. The samples from subgroups G1A (with varnish) and G1B (without varnish) were used as controls and stored in distilled water only for 30 days. The samples were submitted to a compressive strength test after the immersion period. The results were analyzed using the ANOVA 2, Tukey test (5%) and Student's t-test (5%). There were no significant differences between the subgroups, except for the subgroup with varnish protection and immersion in orange juice, which showed reduced GIC compressive strength.

Comparison Of Frequency Of Post Operative Sensitivity In Amalgam Restorations Using Copal Varnish And Dentin Adhesive Liner.

BACKGROUND: Micro leakage around the margins of a restoration is believed to be one of the main causes of postoperative sensitivity. Dental amalgam is a non-insulating material and has the potential to transfer heat and cold causing irritation of the pulp. Different dentin tubule sealers are used under amalgam restoration to compensate for this post-operative sensitivity. This study was conducted to compare the frequency of sensitivity in amalgam restorations using copal varnish and dentin adhesive liner (dentin bonding agent). METHODS: A total of 60 patients of either gender, aged 18-40 years having class 1 carries in posterior teeth were included. Teeth with restorations, dentinal sensitivity and patients taking analgesic drugs for chronic pain conditions were excluded. The selected patients were placed randomly into Group A (copal varnish) & Group B (dentin adhesive liner), by using computer generated table of random numbers. Restored teeth were evaluated 1-month post operatively for sensitivity. RESULTS: Mean age was 25.63±5.42 years. Out of 60 patients, 68.0% were females and 32.0% were males with a female to male ratio of 2:1. The mean post-operative pain score was 2.83±2.79 in Group A and in Group B, it was 1.43±2.14 with a p-value of 0.03. There was no pain on application of a cold stimulus in 14 (46.7%) patients in Group A (copal varnish) while in Group B (Dentin adhesive), no pain was seen in 23 (76.7%) patients with p-value of 0.02. CONCLUSIONS: This study concluded that dentin adhesive liner (dentin bonding agent) is better than copal varnish in reducing postoperative sensitivity in amalgam restorations.

Microleakage of Class II composite resin restorations with self-adhesive composite resin liners.

This study investigated the microleakage of Class II composite restorations with composite resin liners. Standardized box cavities were prepared on the mesial and distal surfaces of 84 extracted intact human molars. Proximal margins were located in enamel (occlusal) and 1.0 mm apical to the cementoenamel junction (gingival). The teeth were randomly divided into 6 groups (n = 28 cavities) and restored with Filtek Z350 nanohybrid composite resin (FZ). The test groups were lined with a conventional flowable composite resin, Premise Flowable (PF), or 1 of 2 self-adhesive composites (SACs): Vertise Flow (VF) or Clearfil SA luting cement (CSA) with or without their respective self-etching adhesives: Optibond All-in-One (OB) or Clearfil SE Bond (CSE). The adhesive/lining procedure was performed as follows: OB/FZ (control), OB/PF/FZ, VF/FZ, OB/VF/FZ, CSA/FZ, or CSE/CSA/FZ. Microleakage was evaluated at the occlusal and gingival margins using a dye penetration technique and quantitative assessment. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data at the significance level of α = 0.05. None of the restorative techniques was capable of preventing microleakage completely. The greatest amount of microleakage was detected in the VF/FZ and CSA/FZ groups at both margins (P < 0.02). Among the groups placed with a bonding agent, OB/VF/FZ showed significantly greater values of microleakage at the occlusal margins than did OB/FZ, OB/PF/FZ, and CSE/CSA/FZ (P < 0.05). At the gingival margins, the OB/PF/FZ group exhibited the least leakage compared with the OB/VF/FZ and CSE/CSA/FZ groups (P < 0.001). The results indicated that the additional application of bonding agents improved the marginal sealing of SACs in Class II composite restorations.

The Influence of Liners on the Pulp Inflammation.

INTRODUCTION: The study included application of liners and dental composites in to cavities of six experimental animals-rabbits (Oryctolagus cuniculus). OBJECTIVE The aim of the study was to investigate rabbit dental pulp response to different liners. Methods Cavity preparation for class V were made on the maxillary central incisors and one lower incisor, while the second lower incisor served as a control tooth. These teeth were restored with the use of one of the following liners--Calcimol LC, ANA Liner and Fuji II LC Improved, and Ceram-X mono dental composite. After an observation period of five days animals were sacrificed and prepared for histological analysis.The existence and degree of the pulp inflammation was determined by using a light microscope. RESULTS: Results showed that the used liners do not cause distortion of the structure and continuity of the odontoblastic layer. Inflammation was not registered in the control group, while in each group of tested materials one tooth with mild signs of hyperemia was registered. Results showed that all three tested liners demonstrated favorable effects on the pulp of the tooth and did not lead to inflammatory reactions. CONCLUSION: Histological analysis of the dental pulp of experimental animals suggests that the liners used in this study do not compromise the integrity of the odontoblastic layer, if it is applied over a thin layer of dentin. In each group of tested materials one tooth with mild signs of hyperemia and vasodilation was registered.

Polymerization shrinkage of different types of composite resins and microleakage with and without liner in class II cavities.

AIM: To determine the volumetric polymerization shrinkage of four different types of composite resin and to evaluate microleakage of these materials in class II (MOD) cavities with and without a resin-modified glass ionomer cement (RMGIC) liner, in vitro. MATERIALS AND METHODS: One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized MOD cavities were prepared. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P 60, Filtek Silorane, Filtek Z 250) with and without a RMGIC liner (Vitrebond). The restorations were finished and polished after 24 hours. Following thermocycling, the teeth were immersed in 0.5% basic fuchsin for 24 hours, then midsagitally sectioned in a mesiodistal plane and examined for microleakage using a stereomicroscope. The volumetric polymerization shrinkage of materials was measured using a video imaging device (Acuvol, Bisco, Inc). Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: All teeth showed microleakage, but placement of RMGIC liner reduced microleakage. No statistically significant differences were found in microleakage between the teeth restored without RMGIC liner (p>0.05). Filtek Silorane showed significantly less volumetric polymerization shrinkage than the methacrylate-based composite resins (p<0.05). CONCLUSION: The use of RMGIC liner with both silorane- and methacrylate-based composite resin restorations resulted in reduced microleakage. The volumetric polymerization shrinkage was least with the silorane-based composite.

Postoperative hypersensitivity and its relationship to preparation variables in Class I resin-based composite restorations: findings from the practitioners engaged in applied research and learning (PEARL) Network. Part 1.

BACKGROUND: This study investigated postoperative hypersensitivity at 1, 4, and 13 weeks following resin-based composite (RBC) restorations of occlusal caries and its relationship with prepreparation (baseline) sensitivity and preparation-related variables, including dentin caries activity, cavity dimension and volume, and lesion radiographic visibility. METHODS: Investigators in a practice-based research network enrolled patients with occlusal caries deemed to require operative treatment. The 45 dental practitioners then placed restorations using their preferred techniques. Complete baseline data on 665 restorations from 602 patients included patient-reported sensitivity (pre-preparation); dentists' ranking of dentin caries on opening the enamel; measurements of preparation depth, width, and length; and patient demographics. At 1, 4, and 13 weeks post-treatment, patients anonymously reported any sensitivity to hot and cold stimuli, sweets, clenching, and chewing, as well as quality-of-life indicators related to the restorations. RESULTS: At baseline, 30% of teeth had reported sensitivities of ≥3 on an anchored scale from 0 to 10 points and were designated as appreciable hypersensitivity (AH). Appreciable hypersensitivity at baseline was related to lesion radiographic visibility and patient age but not to dentin caries activity ranking, type of posterior tooth, gender, or race/ethnicity. Patients reported on 491 restorations at 4 weeks post-treatment--18% had AH. Of those who had AH, 39% (34 of 87) had no baseline AH. With restoration, 63% of teeth with baseline AH no longer had AH. Changes in AH were not associated with preparation depth, length, width, or volume. CONCLUSION: Patient-reported occlusal caries tooth sensitivity was high at baseline and eliminated by RBC restoration in 63% of cases; however, new sensitivity after restoration was reported in 10% of lesions that had none at pretreatment. Sensitivity was not related to preparation dimensions, volume, tooth type, or patient demographics (other than age) in these early lesions.

[Clinical and immunomodulating activity of root canal fillers].

The study revealed higher frequency and intensity of pain after root canal filling with paste Foredent or Zn-eugenol paste in patients with bronchial asthma and showed significant change in the level of sIgA in saliva fluid depending on the filling material and reflecting the effect of root pastes on the local immunity of the oral cavity.

Cytotoxicity of resin-based light-cured liners.

PURPOSE: To evaluate the cytotoxic effects of resin-based light-cured liners on culture of pulp cells. METHODS: Discs measuring 4 mm in diameter and 2 mm thick were fabricated from TheraCal (TCMTA), Vitrebond (VIT), and Ultrablend Plus (UBP). These specimens were immersed in serum-free culture medium (DMEM) for 24 hours or 7 days to produce the extracts. After incubating the pulp cells for 72 hours, the extracts were applied on the cells and the cytotoxic effects were determined based on the cell metabolism (MTT), total protein expression and cell morphology (SEM). In the control group, fresh DMEM was used. Data from MTT analysis and protein expression were submitted to Kruskal-Wallis and Mann-Whitney tests at the preset level of significance of 5%. RESULTS: When in contact with the 24-hour extract, TCMTA, VIT, and UBP decreased the cell metabolism by 31.5%, 73.5% and 71.0%, respectively. The total protein expressed by the cells in contact with VIT and UBP was lower than TCMTA and DMEM (Mann-Whitney, P < 0.05). When in contact with the 7-day extract, TCMTA, VIT, and UBP decreased the metabolic activity by 45.9%, 77.1% and 64.4%, respectively. All the liners expressed statistically lower amounts of proteins when compared to the control. A reduction in the number of cells was observed for all liners. The remaining cells from TCMTA group resembled those from the control group while for VIT and UBP the cells presented significant morphological alterations.

On the diagnosis and management of neurocutaneous syndrome, a toxicity disorder from dental sealants.

Neurocutaneous syndrome, a newly discovered toxicity disorder, is characterized by neurological sensations, pain, depleted energy, and memory loss as well as itchy cutaneous lesions that may invite various opportunistic infections. Components in the calcium hydroxide dental sealants Dycal, Life and Sealapex have been identified as sources of the observed symptoms. Sulfonamide and neurological toxicity issues are discussed, and three case histories are presented. Additional notes on zinc oxide, Fynal, IRM, and Sultan U/P sealers are also included. Diagnostic and management protocols at the Parasitology Center, Inc., are proposed.

Trans-dentinal stimulation of tertiary dentinogenesis.

Trans-dentinal stimulation of tertiary dentinogenesis has long been recognized, and has traditionally been ascribed to diffusion of irritant substances arising during injury and restorative treatment. Identification of bio-active components, especially growth factors including TGF-beta s, sequestered within dentin matrix provides a new explanation for cellular signaling during tertiary dentinogenesis. Both isolated dentin matrix components and pure growth factors (TGF-beta s) have been shown to signal cellular events leading to reactionary and reparative tertiary dentinogenesis. Release of these bio-active components from dentin matrix may arise during carious attack and other injury to the tissue, and also during subsequent surgical intervention and restoration of the tooth. Both cavity-conditioning agents and leaching from restorative materials may contribute to release of these components. Distance of diffusion, as determined by cavity residual dentin thickness, and other restorative parameters may influence the signaling process after release of these components. Careful consideration of the interplay between tissue injury and surgical and restorative material factors is required for optimum exploitation of the exquisite regenerative capacity of dentin-pulp for more biological approaches to clinical treatment of dental disease.

Fluoride varnishes. A review of their clinical use, cariostatic mechanism, efficacy and safety.

BACKGROUND: This is a review of the clinical use, cariostatic mechanism, efficacy, safety and toxicity of fluoride varnishes. TYPES OF STUDIES REVIEWED: The authors reviewed and summarized in vitro, in vivo and in situ studies; clinical trials; demonstration programs; position papers; and editorials published in English in the biomedical literature since 1966. RESULTS: Extensive laboratory research and clinical trials conducted in Europe and elsewhere show that fluoride varnishes are as efficacious as other caries-preventive agents. Fluoride varnishes are widely used in European caries-preventive programs. The U.S. Food and Drug Administration has cleared these products only as medical devices to be used as cavity liners and for the treatment of hypersensitive teeth. These products have not yet been cleared for marketing in the United States as caries-preventive agents. CLINICAL IMPLICATIONS: Three fluoride varnishes are currently available in the United States. Semiannual applications are the most proven treatment regimen. Varnishes are safe and easy to apply and set in contact with intraoral moisture.

Amalgam restorations: postoperative sensitivity as a function of liner treatment and cavity depth.

The purpose of this clinical study was to assess the sensitivity reported by patients following the insertion of class 1 or class 2 amalgam restorations in the treatment of primary carious lesions of different depths. Ninety subjects with previously untreated teeth requiring restorations due to caries lesions were selected: 32 teeth had lesions that were clinically and radiographically judged to be located in the outer one-third of dentin, 30 were located in the middle one-third of dentin, and 28 were located in the inner one-third of dentin. Four different lining regimens were employed: Group 1--no linear; Group 2--two coats of Copalite liner; Group 3--a dentin adhesive resin liner (Scotchbond Multi-Purpose); Group 4--a resin-modified glass ionomer (Fuji Bond LC). Patients were contacted on days 2 and 7 postoperatively and questioned regarding the presence or absence of sensitivity, the stimuli that created the sensitivity, if any, the duration of any sensitivity, and the intensity of any sensitivity using a rating from None to Severe. If sensitivity was experienced on day 7, patients were also contacted on days 14, 30, and 90 to assess the sensitivity at those intervals. The chi-square test of independence showed no significance at the 0.05 level between the different dentin treatments and cavity depths. By day 2, 19% of lesions located in the outer one-third, 27% of lesions located in the middle one-third, and 29% of lesions located in the inner one-third of dentin were sensitive. On day 30, four teeth were still sensitive, two located in the middle one-third and two located in the outer one-third of dentin. On day 90 all teeth were without sensitivity.

Cytotoxicity of a trial resin composite liner containing TiK2F6 on rat dental pulp cells.

The aim of this study was to assess the toxicological responses of a resin composite containing TiK2F6 and NaF in rat dental pulp cells. Trial resin composite liners were made, containing 3 wt% fluorides (TiK2F6 or NaF). These specimens were immersed in 5 ml of cell culture medium supplemented at 37 degrees C for 24 hours. The eluates were used for the experiments. We judged the cytotoxicity of the samples by the cell viability. The original elute solution was serially diluted and then the medium was exchanged for the dilute medium. The cell viability at 1, 2 or 5 days after commencement of re-culturing was calculated. The viability of cells in the eluate from the resin composite liners containing TiK2F6 and NaF decreased with time. The cytotoxicity of TiK2F6 was weaker than that of NaF at all times.

Avaliaçäo da infiltraçäo marginal em cavidades de classe II restauradas com resina composta associada a outros materiais restauradores / Evaluation of marginal leakage in different materials applied at to class II cavities restorations in association with composite resin

As resinas compostas vêm sofrendo inúmeras alteraçöes, com o objetivo de tornar o seu uso adequado para restauraçöes de dentes posteriores, entretanto, problemas clínicos associados à sua utilizaçäo säo comumente observados, dentre eles, a microinfiltraçäo marginal. Algumas alternativas clínicas têm sido sugeridas, na tentativa de reduzir as falhas decorrentes do emprego deste material, principalmente em restauraçöes estendidas à regiäo do cemento, local este onde os problemas se agravam. O objetivo deste trabalho consistiu, portanto, em estudar a efetividade do vedamento marginal de diferentes materiais aplicados no terço cervical com término em cemento para, em associaçäo à resina composta, restaurar esteticamente cavidades de classe II, através da técnica mista, avaliando-se com esta finalidade o índice de infiltraçäo marginal tanto na interface cemento/material, quanto na interface dos materiais restauradores. Cavidades MOD com margens cervicais estendidas além da junçäo amelocementária foram confeccionadas em 84 dentes pré-molares humanos livres de cáries, os quais foram distribuídos em grupos de 12 elementos cada, correspondendo a 7 condiçöes experimentais...