Clinical Success of Fiber-reinforced Composite Resin as a Space Maintainer.

INTRODUCTION: The early loss of deciduous molars is a frequently encountered problem in dentistry. Various space maintainer designs were developed to prevent the loss of the space. The aim of this study was to evaluate long-term clinical performance and survival rates of fiber-reinforced composite resin (FRCR) as a space maintainer clinically. MATERIALS AND METHODS: This study was designed on 44 children who had early missed deciduous molars. Space maintainers were prepared on plaster models of patients and fixed directly to the adjacent teeth. Survival rate and whether it causes any damage to adjacent teeth were examined clinically and radio-graphically for 24 months or until failure. Kaplan-Meier survival analysis was used for the statistical analyses. RESULTS: Overall, 16.2% of space maintainers were dislodged and accepted to be failed at the end of 12 months. At the 24-month control, 52.2% success was stated with the FRCR space maintainer and because of permanent tooth eruption, 31.8% of space maintainer were taken out. The mean duration of space maintainers was measured to be 14.8 ± 3.48 months. There was no statistical significance between survival time and gender, tooth number, localization, and measured space (p > 0.05). CONCLUSION: After all 24 months follow-up, as well as esthetic properties of FRCR space maintainer, their applicability in a single seance and strength against the forces are determined as the advantages of the technique. CLINICAL SIGNIFICANCE: The FRCR space maintainers can be thought of as alternatives to metal space maintainers.

Survival rates of anterior composites in managing tooth wear: systematic review.

The use of composite restorations for patients with tooth wear is considered as a more conservative treatment option. The aim of this study was to systematically review the literature investigating the survival rates of anterior composite restorations when used in managing tooth wear in patients. PubMed and MEDLINE (Ovid) databases were screened for studies from 1995 to 2015. Cross-referencing was used to further identify articles. Article selection and data extraction were performed in duplication. Languages were restricted to English. A quality appraisal of included studies was carried out using the Strength of Recommendation Taxonomy system. Six hundred and sixty-six articles were initially identified from which eight articles were full-text reviewed. Six articles involving five studies were selected for inclusion. Three studies were prospective and two retrospective. Included studies involved placement of 772 direct and indirect anterior composite restorations in 100 patients with follow-up periods between 5 months and 10 years. The survival rates of anterior composites were >90% and 50% at 2.5 and 5 years, respectively. Posterior occlusion was re-established in 91% of patients within 18 months. Meta-analysis could not be performed due to the heterogeneity of included studies. The systematic review's overall strength of recommendation was graded B. There is evidence to support the use of anterior composite restorations at an increased vertical dimension of occlusion in the short/medium-term management of tooth wear. Long-term reporting of outcomes remains limited. Further research is needed with standardised study design, detailed reporting of outcomes and long-term review.

12 Years of Repair of Amalgam and Composite Resins: A Clinical Study.

OBJECTIVE: The objective of this study was to clinically evaluate repaired posterior amalgam and composite restorations over a 12 year period, investigate the influence of repair in the survival of restorations, and compare their behavior with respect to controls. METHODS: Thirty-four patients, 18 to 80 years of age with 167 restorations, 67 composite resin (RC), and 100 amalgam (AM) restorations, participated. Restorations with localized, marginal, anatomical deficiencies and/or secondary caries, and "clinically judged" suitable for repair or replacement according to US Public Health Service (USPHS) criteria, were randomly assigned to four groups: repair (n=35, 20 AM, 15 RC), replacement (n=43, 21 AM, 22 RC), positive control (n=71, 49 AM, 22 RC), or negative control (n=18, 10 AM, 8 RC). The quality of the restorations was blind scored according to the modified USPHS criteria. Two examiners scored them at initial status (κ=0.74) and after one to five, 10, and 12 years (κ=0.88). Wilcoxon and Mann-Whitney tests provided for comparisons within the same group and between years, respectively. RESULTS: After 12 years, all groups behaved similarly in marginal adaptation, marginal stain, teeth sensitivity, anatomic form, and luster ( p≥0.05). Better behavior in roughness was observed in replaced RC ( p=0.049). CONCLUSIONS: Given that most clinical parameters investigated were similar between all groups during the follow-up, the repair of RC and AM restorations is a good clinical option because it is minimally invasive and can consistently increase the longevity of restorations.

Biomechanical Effects of Bonding Pericervical Dentin in Maxillary Premolars.

INTRODUCTION: Pericervical dentin (PCD) loss may increase root fracture propensity in root-filled teeth. This study evaluated the impacts of bonding PCD with composite resin (CR) on radicular microstrain distribution and load at failure of root-filled maxillary premolars. METHODS: Ten single-canal maxillary premolars decoronated 2 mm coronal to the cementoenamel junction (CEJ) had canals enlarged with ProTaper Universal instruments (Dentsply Tulsa Dental Specialties, Tulsa, OK) to F3. They were root filled with gutta-percha (GP) to the CEJ and restored with Cavit (3M Deutschland GmbH, Neuss, Germany) (GP group, n = 5) or 6 mm apical to the CEJ and restored with bonded CR to simulate bonding of PCD (bonded PCD group, n = 5). Digital moiré interferometry was used to evaluate pre- and postoperative whole-field microstrain distribution in the root dentin under physiologically relevant loads (10-50 N). Another 30 premolars, similarly treated as groups 1 and 2 or left untreated as controls (n = 10/group), were subjected to cyclic loads (1.2 million cycles, 45 N, 4 Hz) followed by uniaxial compressive load to failure. Mechanical data were analyzed with 1-way analysis of variance and the post hoc Tukey test at a 5% level of significance. RESULTS: Microstrain distribution showed bending and compressive patterns at the coronal and apical root dentin, respectively. In the GP group, microstrain distribution was unaltered. In the bonded-PCD group, different microstrain distribution suggested stiffening at the PCD. The load at failure did not differ significantly for the GP, bonded PCD, and control groups (P > .05). CONCLUSIONS: CR bonding of PCD might impact the biomechanical responses in maxillary premolar roots at low-level continuous loads. The effect of this impact on root fracture loads when subjected to cyclic load warrants further investigation.

FDI report on adverse reactions to resin-based materials.

Resin-based restorative materials are considered safe for the vast majority of dental patients. Although constituent chemicals such as monomers, accelerators and initiators can potentially leach out of cured resin-based materials after placement, adverse reactions to these chemicals are rare and reaction symptoms commonly subside after removal of the materials. Dentists should be aware of the rare possibility that patients could have adverse reactions to constituents of resin-based materials and be vigilant in observing any adverse reactions after restoration placement. Dentists should also be cognisant of patient complaints about adverse reactions that may result from components of resin-based materials. To minimise monomer leaching and any potential risk of dermatological reactions, resin-based materials should be adequately cured. Dental health care workers should avoid direct skin contact with uncured resin-based materials. Latex and vinyl gloves do not provide adequate barrier protection to the monomers in resin-based materials.

Preventing postoperative tooth sensitivity in class I, II and V restorations.

Postoperative tooth sensitivity in Class I, II and V resin-based composite restorations continues to be an unpredictable problem in dentistry. In spite of meticulous use of dentin bonding agents, dentists and patients are faced with the sensitivity problem and the frustrating need to remove restorations and occasionally accomplish endodontic therapy on teeth that were not sensitive before the restorations were placed. Practitioners have developed numerous preventive methods to overcome the sensitivity challenge, which I have described in this article.

Clinical evaluation of a resin composite and bonding agent in Class I and II restorations: 2-year results.

OBJECTIVE: The purpose of this study was to evaluate the clinical performance and longevity of Tetric Ceram and Syntac Sprint restorations in stress-bearing areas performed in general practice. METHOD AND MATERIALS: The light-curing resin composite Tetric Ceram in combination with the bonding material Syntac Sprint were used as restorative materials in three public dental health clinics. All the restorations were done by general practitioners in an ordinary patient pool attending a public health clinic. Before starting, the general practitioners were instructed and trained in performing the restorations according to a standardized clinical procedure, and the evaluations were done according to United States Public Health Service criteria. One hundred forty-eight restorations (27 Class I, 121 Class II) were done in 123 patients. After 2 years, 140 restorations (95%) could be assessed. Color slides and bitewings were taken to supplement the clinical evaluations of color match, marginal discoloration, secondary caries, and marginal adaptation. Wear of the restorations was evaluated according to the Leinfelder method. RESULTS: After 2 years, 7 out of 148 restorations had failed, giving a failure rate of 5% of the tested materials. Five restorations failed due to hypersensitivity, one to secondary caries, and one to fracture. The wear rate was low (mean 37 microm) and did not result in any replacement. CONCLUSION: This 2-year study showed that clinically satisfactory results could be obtained using resin composite Class I and II restorations in stress-bearing areas done in general practice on an ordinary clientele when the clinical procedure is standardized.

[New direct restorative materials]. / Nieuwe directe restauratiematerialen.

People worldwide have become increasingly aware of the potential adverse effects on the environment, of pollution control and of toxic effects of food, drugs and biomaterials. Amalgam and its potential toxic side effects (still scientifically unproven) continue to be discussed with increasing controversy by the media in some countries. Consequently, new direct restorative materials are now being explored by dentists, materials scientists and patients who are searching for the so-called 'amalgam substitute' or 'amalgam alternative'. From a critical point of view some of the new direct restorative materials are good with respect in aesthetics, but all material characteristics must be considered, such as mechanical properties, biological effects, and longterm clinical behaviour.

[Long-term results of front teeth restoration using light-curing composite materials]. / Otdalennye rezul'taty vosstanovleniia frontal'nykh zubov kompozitnymi materialami otverzhdeniia.

200 patients (500 restorations of front teeth) were examined. All the restorations were made of light-curing composite materials (microfills, hybrids, compomers, and combination of microfills and hybrids) from 5 do 9 years ago. Clinical and esthetical parameters were evaluated. We had to replace 96 restorations of 500 (19.2%), only 50 (10%) restorations were marked as "excellent". Direct veneers made of microfilled composite materials showed the best results (30%--"excellent" restorations). The restorations of devital teeth and V-class restorations of compomer material show the worse result (20% restorations replaced).

Summary of: dental composite materials and renal function in children.

OBJECTIVE: To examine whether greater exposure to resin-based composite materials, which may intra-orally release bisphenol A (BPA), is associated with worse renal function outcomes in children. DESIGN: Prospective multi-centre study. SETTING: Community health dental clinics in Boston and Maine from 1997-2005. SUBJECTS AND METHODS: Five hundred and thirty-four New England Children's Amalgam Trial participants aged six to ten years were randomised to treatment with amalgam or resin-based composite restorations over five years of follow-up. INTERVENTIONS: Restorations were placed according to treatment arm, and sealants placed per standard of care. Cumulative composite exposure was calculated using surface-years (each treated surface weighted by number years present). MAIN OUTCOME MEASURES: Urinary excretion of albumin, gamma-glutamyl transpeptidase (gamma-GT), and N-acetyl-ß-D-glucosaminidase (NAG) were available for 417 children. RESULTS: Analysis of covariance showed no association between exposure to dental composites, polyacid-modified compomer, or flowable composite dental sealants and preventative resin restorations with levels of renal function. There was no association between composite materials and thresholds indicating renal damage in logistic regression models. CONCLUSIONS: This study found no harmful associations between dental composite materials and renal function in children. Therefore, concerns about renal function need not be a consideration in the choice of dental restoration material or placement of preventative dental sealants.

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.

Microleakage of nanofilled resin-modified glass-ionomer/silorane- or methacrylate-based composite sandwich Class II restoration: effect of simultaneous bonding.

OBJECTIVES: Microleakage of composite restorations at the cervical margin placed apically to the cementoenamel junction (CEJ) is still a concern. This study evaluated the effect of simultaneous bonding application on cervical sealing of nano-ionomer/silorane- or methacrylate-based composite open sandwich Class II restorations in the modified technique compared with that of conventional bonding. METHODS AND MATERIALS: In 60 sound maxillary premolars, two standardized Class II cavities were prepared with cervical margins 1 mm below the CEJ. The teeth were randomly divided into six groups of 10 teeth each. In the first three groups (groups 1-3), Clearfil SE Bond and Clearfil APX (Kuraray) were used for restoration in the total bonding technique (group 1), conventional open sandwich technique associated with a nano-ionomer (Ketac N100, 3M ESPE) (group 2), and modified open sandwich technique with simultaneous bonding application for both nano-ionomer and composite (group 3). In the second three groups (groups 4-6), Silorane Adhesive and Filtek Silorane composite (3M ESPE) were used in the same manner as in the first three groups, respectively. RESULTS: The simultaneous bonding application in the modified sandwich restorations (with SE Bond or Silorane Adhesive) resulted in a significant reduction of the cervical microleakage compared with that of the conventional bonding (p<0.05). However, microleakage of the modified technique was similar to that of the total bonding (with SE Bond or Silorane Adhesive) (p>0.05), both showing good marginal seal.

Contração de polimerização das resinas compostas convencionais X resinas Bulk Fill ­ revisão de literatura / Polymerization shrinkage of conventional composite X Bulk Fill resins ­ literature review

Desde o surgimento das resinas compostas na década de 50, vários aperfeiçoamentos nas propriedades físicas e mecânicas ocorreram visando suprir as necessidades qualitativas. O trabalho proposto visa apresentar uma revisão de literatura acerca do comportamento das resinas compostas frente à contração de polimerização e o surgimento das resinas do tipoBulk Fill, que propõem características inovadoras utilizando incrementos de até 4 mm. As resinas compostas passaram por diversas fases de diferenciação dos seus componentes a fim de controlar reações indesejáveis, como a contração de polimerização, sorção de água, rugosidades superficiais, adaptação marginal, até chegar aos componentes nanoparticulados, com melhores propriedades químicas, físicas e mecânicas. Atualmente, surge um novo modelo de resina: as resinas Bulk Fill, as quais permitem o preenchimento da cavidade com incremento único de até 4 mm. As resinas ganharam novas formas. As alterações mecânicas e físicas melhoradas beneficiam a qualidade operacional e a técnica restauradora. A nova proposta dessas indica a redução do estresse de contração, diminui os riscos dos efeitos indesejáveis pós-operatórios e possui o tempo operacional reduzido (AU).

Since the emergence of the composite resins in the 50´s several improvements have occurred in their physical and mechanical properties, in order to improve their quality requirements. The proposed work aims to present a literature review about the composite resins behavior front of the polymerization shrinkage and the emergence of Bulk Fill or single filling resin type, which offers innovative features using increments of up to 4 mm. The composite resins have gone through various stages of differentiation of its components, in order to control undesirable reactions such as polymerization shrinkage, water sorption, surface roughness, marginal adaptation, until the nanoparticle components with better chemical, physical and mechanical properties. Nowadays, it emerges a new model of resin: Bulk Fill type, which allows the cavity filling with single increment of 4 mm. The resins have gained new types. The mechanical and physical changes benefit the operational quality of restorative technique. The new proposal of these resins indicates the contraction stress reduction, decreases the risks of undesirable postoperative effects, and reduces the operational time (AU).

Influência do modo de foto ativação no grau de conversão, e adaptação marginal e interna de restaurações classe II com resinas compostas bulk fill / Influence of light curing mode on degree of conversion, and marginal and internal adaptation of class II bulk fill resin restoration

O objetivo deste estudo foi avaliar a efetividade de diferentes modos de foto ativação das resinas compostas bulk fill comparando com as resinas convencionais, analisando sua influência na irradiância, no grau de conversão, assim como na formação de fendas internas e marginais em restaurações classe II tipo slot vertical, após envelhecimento artificial. Cento e sessenta incisivos bovinos foram cortados e desgastados para simular dentes posteriores, nos quais foram realizados preparos classe II. Os espécimes foram divididos em quatro grupos de acordo com o material restaurador utilizado: Tetric N-Ceram Bulk Fill (TB), Admira Fusion X-tra Bulk fill (AB), Tetric N-Ceram (TC) e GrandioSO (GO). As resinas bulk fill foram inseridas em incremento único de 4 mm e nos demais grupos foi utilizada a técnica incremental oblíqua (2 mm). A foto ativação foi realizada com os aparelhos do tipo Monowave (MW) ou Polywave (PW) nos dois modos (alta intensidade continua e rampa). A medição da irradiância foi feita utilizando espectroradiômetro Patient Simulator (MARC-PS). O grau de conversão foi avaliado através da reflectância total atenuada (ATR) do espectrômetro (FTIR). As superfícies superiores das amostras foram irradiadas in loco durante 20 s. O espectro da superfície inferior foi registrado em tempo real e após 15 min da irradiação. As fendas foram avaliadas em estereomicroscópio (50x). As fendas marginais externas foram avaliadas antes e após a ciclagem termomecânica. Para fenda interna, os espécimes foram seccionados e então avaliados. Os dados foram submetidos à ANOVA umo e dois fatores e teste Tukey. Em relação á irradiância o aparelho LED Monowave apresentou maior valor de irradiância (1822,2 mW/cm2 - AIC; 1748,1 mW/cm2 - R); na análise do GC, o teste ANOVA dois fatores mostrou diferença significativa (p<0,05) para o fator tipo de resina. A resina TB apresentou o menor grau de conversão, e AB o maior GC. Para fenda marginal foi encontrada diferença significativa para o fator fotopolimerização e interação resina x fotopolimerização (p<0,05). Resina TC fotopolimerizada PW/AIC apresentou maior média de fenda marginal (13,94 µm) e TC fotopolimerizada MW/AIC a menor (9,59 µm). Após o envelhecimento termomecânico a resina GO fotopolimerizada PW/R apresentou maior porcentagem de aumento de fenda marginal (48,54%) e maior fenda interna quando fotopolimerizada MW/AIC (85,05 µm). Concluiu-se que o tipo fotopolimerização não influenciou no grau de conversão. As restaurações polimerizadas com o fotopolimerizador Polywave apresentaram os maiores valores de fenda marginal externa. As resinas bulk fill apresentaram menores valores de fenda marginal e interna após o envelhecimento termomecânico quando comparadas com restaurações de resinas convencionais(AU)

The objective of this study was to evaluate the influence of different photo activation modes on irradiance, the degree of conversion and formation of internal and external gaps in class II restorations using bulk fill resins. One hundred and sixty bovine incisors were cut and worn to simulate posterior teeth, in which class II preparations were performed. The specimens were divided into four groups according to the restorative material used: Tetric N-Ceram Bulk Fill (TB), Admira fusion X-tra Bulk fill (AB), Tetric N-Ceram (TC), GrandioSO (GO). The bulk fill resins were inserted in a single increment of 4 mm, and in the other groups, the incremental oblique technique was used. The photo activation was performed with a Monowave (MW) or Polywave (PW) light curing devices selecting two modes (high continuous intensity (HCI) and soft start (SS)). The irradiance measurement was performed using Patient Simulator (MARC-PS) in HCI and SS modes, for 20 s. For the degree of conversion, 2 mm and 4 mm high and 5 mm diameter molds were prepared for resin insertion directly on the attenuated total reflectance (ATR) spectrometer (FTIR). The upper surfaces of the samples were irradiated in situ for 20 s with the light curing apparatus in the modes (HCI) and (SS), the lower surface spectra was recorded continuously in real time and then at 15 min after irradiation. For the evaluation of the external gap each specimen was evaluated twice, one before and one after the thermomechanical cycling. For internal gap, the specimens were sectioned and evaluated using the stereomicroscope using a 50x magnification. About the irradiance, the Monowave LED showed the highest irradiance values (1822,2 mW/cm2 - HCI; 1748,1 mW/cm2 - SS), in the DC analysis, the two way ANOVA test showed significant difference (p <0.05) for the resin type. TB showed the lowest DC, with a statistical difference for AB. For the marginal gap, a significant difference was found for the photopolymerization factor and resin x photopolymerization interaction (p <0.05). TC light cured by PW/HCI showed the highest average marginal gap (13.94 µm) and TC light cured by MW / HCI revealed the lowest (9.59 µm) marginal gap. After thermomechanical aging, GO light cured by PW / SS had a higher percentage of increasing marginal gap (48.54%) and the highest internal gap when light cured by MW / HCI (85.05 µm). It was concluded that the type of photopolymerization did not influence the degree of DC. The restorations light cured by PW device showed the highest external marginal gaps. Bulk fill resins exhibited lower marginal and internal gap values after thermomechanical aging when compared with conventional resin(AU)