Does a black light lens aid in composite removal?

OBJECTIVE: To evaluate the effectiveness of a black light lens as visual aid in composite restoration removal. Lost tooth structure, residual composite, and removal time were compared for operators with different levels of experience. METHODS: Occlusal preparations in 24 matched-pair extracted molars were etched, bonded, restored with composite, and thermocycled. The restored teeth were radiographed and two faculty and two student doctors removed the restorations with or without a black light lens while time was recorded. Digital scans of the cavity before and after restoration removal were used to calculate lost tooth structure and residual composite. RESULTS: Removal of restorations resulted in tooth structure loss and left residual composite. The use of the black light lens had no significant effect (two-way ANOVA; p value >0.05). However, operator experience significantly affected operating times and average depth of tooth structure loss (two-way ANOVA; p value <0.05). Student doctors assisted by the black light lost less tooth structure than experienced operators and improved their operating times (multiple comparisons; p value <0.05). CONCLUSIONS: The black light lens did not conserve tooth structure or avoid composite remnants compared to routine operation, nor affected the operating time. However, less-experienced operators did benefit from the black light in conserving tooth structure and time. CLINICAL SIGNIFICANCE: Replacement of defective composite restorations is a regular practice in restorative dentistry. When existing composite restorations are removed, loss of tooth structure is unavoidable. A black light lens might improve the ability of operators with less experience to conserve tooth structure even though it did not provide benefits for the experienced operators.

Do composite resin polishing systems damage enamel?

Finishing and polishing of composite resin restorations may cause damage to the bordering enamel. Although many studies have investigated the effect of polish on restorative materials, few have quantified the effect on bordering enamel. The objective of this study was to compare enamel loss surrounding composite restorations after finishing and polishing sequences. The null hypothesis was that there would be no difference in enamel loss between different finishing and polishing sequences. Class V preparations on the buccal and lingual surfaces of 15 extracted human molars were restored with a composite resin and assigned to 1 of 2 finishing and polishing sequences, so that each tooth underwent both sequences (n = 15 per sequence). In sequence 1, a tungsten carbide finishing bur and aluminum oxide polishing discs were used; in sequence 2, a diamond finishing bur, aluminum oxide-impregnated finishing cup, and diamond-impregnated polishing cup were used. Tooth surfaces were scanned with an optical scanner after preparation, finishing, initial polishing, and final polishing. The finishing and polishing scans were aligned to the preparation scan using Cumulus software. The depth of enamel surface loss was calculated and statistically analyzed (α = 0.05; paired t test). Most enamel loss (mean [SD]) resulted from the finishing step with the tungsten carbide bur (51.8 [21.3] µm) or diamond bur (43.3 [12.6] µm). Each polishing step increased mean enamel loss by only a few microns. There was no statistically significant difference between the 2 finishing and polishing sequences. The majority of enamel damage during finishing and polishing of composite resin restorations resulted from the finishing burs. Little enamel was removed by either of the tested composite resin polishing systems.

In vivo Microbial Diversity Analysis on Different Surfaces of Dental Restorative Materials via 16S rDNA Sequencing.

BACKGROUND This study aimed to provide precise material selection guidance for proper clinical restoration and treatment of plaque-related oral diseases, such as dental caries and periodontal diseases. MATERIAL AND METHODS Four groups (n=24) of restorative material sheets (n=24) were prepared using 3M Z350 composite resin (ZR), zinc phosphate cement (ZPC), glass-ionomer (GI), and ICON permeable resin (IPR). Six volunteers wore a plaque-collection device equipped with the 4 restorative material sheets for 48 hours. Plaque samples were collected, and Miseq sequencing was applied to obtain template DNA fragments for microbial diversity analysis. The data were analyzed with nonparametric tests. RESULTS The microbial diversity on the ZPC surface was significantly lower than that on GI and IPR surfaces. The abundance of Firmicutes and Streptococcus on the ZPC surface was significantly higher than on the surfaces of GI and IPR. In contrast, the abundance of Porphyromonas on the surface of ZPC was significantly lower than that on GI and IPR surfaces. (P<0.05). CONCLUSIONS The results of the present study might serve as a basis for material selection under different oral microbial conditions to provide more accurate treatments and restorative procedures in the oral cavity.

The influence of a selected desensitizer on marginal microleakage of a class V composite restoration subjected to thermocycles: an in vitro study.

INTRODUCTION: Dentin hypersensitivity is a painful clinical condition. The frequency of its occurrence varies from 8 to 57%, depending on tested group and different methods of investigations. Recommended desensitizing agents have different mechanism of action and effectiveness. We are still looking for solutions that will improve their effectiveness and simultaneously allow for wider use of e.g. as a base material, counteracting postoperative hypersensitivity, reducing marginal microleakage. The aim of the study was to assess the effect of a selected desensitizing agent occluding dentin tubules with calcium hydroxyapatite on marginal microleakage formation of a class V composite restorations subjected to thermocycles. MATERIALS AND METHODS: In study it was used 40 molars and premolars, which were alternately assigned into two groups. In both groups standardized cavities were prepared. In the study group (study group - SG) before application of bonding agent Teethmate Desensitizer (f. Kuraray, Noritake Dental Inc., Okayama, Japan) was used. In the control group (control group - CG) OptiBond All-in-one (f. Kerr, Bioggio, Switzerland) bonding agent was used and cavities were filled using composite material Gradia Direct (f. GC Europe N.V., Leuven, Belgium). After storage in saline, teeth were subjected to 600 thermocycles, passive dye penetration test was done, teeth were cut in the area of filling, according to its long axis. Under light microscope magnification value of microleakage was measured and marginal microleakage rate (M) was counted. The results of the tests were statistically analyzed using the package STATISTICA 12.0 (StatSoft, USA). RESULTS: The average value of M for the SG group was 0.46 (min 0.05, max 0.76, SD 0.226) and for CG was 0.22 (min 0, max 0.74, SD 0.235). The differences between M values were statistically significant (p = 0.0094). CONCLUSION: A reduction in the number of retention sites for the bonding system, facilitates the formation of microleakage in the experimental conditions and reduces the degree of adhesion of the composite material to the hard tissues of the tooth.

Tooth crown discoloration induced by endodontic sealers: a 3-year ex vivo evaluation.

OBJECTIVES: The aim of this study was to evaluate the tooth crown discoloration induced by commonly used and new-generation endodontic sealers after 1 month and 1 and 3 years. MATERIALS AND METHODS: The crowns of 60 extracted incisors were cut and the pulp chambers were cleaned. The specimens were divided randomly into four groups (n = 15 each). Pulp chambers were filled with Pulpispad in group 1, AH26 in group 2, MTA Fillapex in group 3, and EndoREZ in group 4. Specimen color was measured with a spectrophotometer before and after sealer placement. Commission International de L'Eclairage's (CIE's) lighteness (L*), red-green (a*), yellow-blue (b*) color system values and color difference (ΔE) were recorded at 1 month and 1 and 3 years. Data were analyzed using repeated-measures analysis of variance and Tukey's honestly significant difference test (α = 0.05). RESULTS: All sealers caused discoloration. At 1 month, ΔE values were significantly higher in groups 1 and 2 than in groups 3 and 4 (p < 0.05). At 1 year, ΔE values were significantly lower in group 3 than in the other groups (p < 0.05). At 3 years, ΔE values were significantly higher in group 1 than in the other groups (p < 0.05). CONCLUSIONS: All tested sealers induced varying chromatic alterations. After root canal obturation, thorough debridement of sealers from the pulp chamber is essential for the prevention of sealer-induced discoloration. CLINICAL RELEVANCE: Tooth discoloration induced by endodontic materials is a problem for clinicians and patients and may impair the esthetic of endodontically treated teeth. Therefore, evaluation of long-term discoloration effects commonly used, and new-generation endodontic sealers were purposed in this study.

Resin-modified glass ionomer cement vs composite for orthodontic bonding: A multicenter, single-blind, randomized controlled trial.

INTRODUCTION: In this study, we aimed to compare the incidence of new demineralized lesions and bond failures between 2 groups of participants wearing fixed orthodontic appliances bonded with either light-cured resin-modified glass ionomer cement or light-cured composite. METHODS: This trial was a multicenter (6 centers: 2 teaching hospitals, 4 specialist orthodontic practices), single-blinded, randomized controlled trial with 2 parallel groups. Patients aged 11 years or older, in the permanent dentition, and about to start fixed orthodontic treatment in these 6 centers were randomly allocated to have either resin-modified glass ionomer cement or light-cured composite for bonding brackets, forward of the first molars. Pretreatment and day-of-debond digital photographic images were taken of the teeth and assessed by up to 5 clinical and 3 lay assessors for the presence or absence of new demineralized lesions and the esthetic impact. The assessors were masked as to group allocation. RESULTS: We randomized 210 participants, and 197 completed the trial. There were 173 with complete before-and after-digital images of the teeth. The incidence of new demineralized lesions was 24%; but when the esthetic impact was taken into account, this was considerably lower (9%). There was no statistically significant difference between the bracket adhesives in the numbers with at least 1 new demineralized lesion (risk ratio,1.25; 95% confidence interval, 0.74-2.13; P = 0.403) or first-time bracket failure (risk ratio,0.88; 95% confidence interval, 0.67-1.16; P = 0.35). There were no adverse effects. CONCLUSIONS: There is no evidence that the use of resin modified glass ionomer cement over light-cured composite for bonding brackets reduces the incidence of new demineralized lesions or bond failures. There might be other reasons for using resin modified glass ionomer cement. REGISTRATION: This trial was registered at ClinicalTrials.govNCT01925924. PROTOCOL: The protocol is available from the corresponding author on request.

In vivo assessment of genotoxicity in buccal cells of children undergoing tooth restoration.

OBJECTIVES: Whereas dental materials came in direct or close contact with oral tissue, it is a great concern about the biocompatibility of those materials. This study was performed to evaluate possible DNA damage to buccal cells exposed to dental materials. METHODS: This prospective, longitudinal clinical study was conducted over a three months period. Class II restorations were placed in 60 young patients with no previous filling using one of three tested dental materials (two glass ionomers; Ketac Molar and Ionofil Molar and one compomer material; Twinky Star). DNA damage was analysed by micronucleus assays, in buccal exfoliated epithelial cells. RESULTS: In patients treated with Ketac Molar, a significant frequency of micronuclei (p = 0.027) and binucleated cells in samples taken 30 days following restoration (p = 0.029) was confirmed. In patients treated with Twinky Star, a statistically significant increase in the number of binucleated cells in samples taken after 7 and 30 days following restoration (p = 0.001 and p < 0.001, respectively) was observed. In all samples collected 90 days after treatment, there was no statistical difference in the number of any cell changes. CONCLUSION: In this study long-term biocompatibility of tested materials was confirmed. Glass ionomers and compomers are widely used materials in paediatric dentistry, and this study has proved their safety for usage in children.

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.

Effects of New Generation All-Ceramic and Provisional Materials on Fibroblast Cells.

PURPOSE: The purpose of this in vitro study was to evaluate the cytotoxic and apoptotic effects of seven new-generation all-ceramic materials for CAD/CAM (Lava Ultimate [LU], VITA Mark II [VM], InCoris TZI [IC], IPS e.max CAD [EM], VITA Suprinity [VS], Cerasmart [CS], IPS Empress CAD [EC]) and six provisional materials (Protemp 4 [PT], Telio CAD [TC], CAD-Temp [CT], Telio Lab [TL], Temdent Classic [TD], Telio CS C&B [TS]) on L929 mouse fibroblast cells. MATERIALS AND METHODS: 24 disc-shaped specimens (∅ = 5 mm, h = 2 mm) were prepared from each test material. Medium extracts were collected at the 1st, 3rd, and 7th days for each group and tested using the L929 cell line. Cytotoxicity was evaluated using XTT assay, and apoptosis was determined by Annexin-V/PI staining. Data were analyzed using one-way ANOVA, Tukey's multiple comparison tests at a significance level of p < 0.05. RESULTS: The cell viability results among all-ceramic material groups after the 1st and 7th days of incubation periods showed statistically significant differences (p < 0.05). There were significant differences within the ceramic groups in different incubation periods regarding apoptosis rate (p < 0.05). Throughout the entire test period, LU and VM from the CAD/CAM all-ceramic materials and PT and TC from the provisional restoration materials showed cell viability higher than 90%. EC and TD showed the lowest cell viability and highest apoptosis rates in their own groups. For the provisional materials, there were significant differences in cell viability and apoptosis rate in all the incubation periods for each material (p < 0.05). CONCLUSIONS: Although some new-generation CAD/CAM and provisional restoration materials display slight cytotoxicity values, the results are still within the reliable range, and they can safely be used in clinical conditions.

Cytotoxic effects of new-generation bulk-fill composites on human dental pulp stem cells.

This study was performed to evaluate possible DNA damage in cells of human origin exposed to dental composites in vitro using a cytotoxic assay. Five bulk-fill composites were filled in molds and irradiated for 20 s. DPSCs were inoculated into 24-well plates. After the insert membrane was inserted and composites were added and the experiment was continued for 24/72 hours. In order to investigate the effects of the materials on DPSCs; its effect on apoptosis-regulating Bcl-2 gene, Human Beta-Defensins (HBDs 1-2) gene, Interleukin 6, 8, 10 expression level was examined. Also in order to check the cellular viability and stress factors; MTT assay, Total Antioxidant and Oxidant Status kits were used. At both irradiation times, all composites significantly affected analyses parameters used in primary DNA damage assessment or induced significant formation of cellular death. Cytotoxicity was detected in TE<SS<FBF<XB<VBF groups at 24 hour, and after 72 hour this sequence has changed.

Optimizing quality and safety of dental materials.

This paper discusses aspects of quality and safety improvement of the most commonly used dental restorative materials, the resin-based composites. From a patient's perspective, long-lasting resin-based restorations without complications are important. Recurrent caries and fracture are the most common causes for restoration failures. Proper handling and curing of the composites improve the mechanical properties of the restorations and increase safety by reducing exposure to residual methacrylate monomers. A number of compounds have been introduced in restorative materials to reduce the risk of recurrent caries, even though a real breakthrough has not yet been achieved. It is concluded that simple measures may improve the quality and safety of resin-based composite restorations.

Gingival tissue reaction to direct adhesive restoration: A preliminary study.

INTRODUCTION: It is debated whether composite resin marginal/submarginal direct restoration can be usefully performed without inflammatory consequences. This histological study is the first human analysis aimed to compare, in the same tooth, the gingival tissue close to composite resin restorations with gingival tissue close to hard tissue. METHODS: Eight healthy patients with almost a residual strategic tooth needing endodontic therapy, and post-and-core restoration, then indirect prosthetic restoration, were selected. Direct margin relocation with composite resin was necessary to perform endodontic treatment. The crown lengthening with a secondary flap harvested was necessary to perform prosthetic rehabilitation. Three months after marginal relocation, the secondary flap was harvested, embedded in PMMA, 4-µm sectioned, and stained to analyze the inflammation degree. RESULTS: All patients completed post-and-core reconstruction and the planned prosthetic therapy, maintaining the stringent hygienic protocol plan. The inflammation level comparison, slightly lower in gingiva close to the teeth (3.62 ± 0.38) than in gingiva close to the composite (3.75 ± 0.26), results in a p-value of 0.11 after Wilcoxon test. CONCLUSIONS: Results highlight a minimal, statistically not significant difference in the inflammation degree after margin relocation, conceivably due to patients, teeth and cases selection, together with adopted stringent methodological and supportive measures.

Evaluation of Radiopacity of Luting Cements Submitted to Different Aging Procedures.

PURPOSE: To evaluate the radiopacity of luting cements submitted to different aging procedures. MATERIALS AND METHODS: Twenty discs (1 × 4 mm) of each of the following cements were prepared: zinc phosphate, RelyX Luting 2, Variolink 2, AllCem, RelyX U200, Multilink, Panavia F2.0, and RelyX ARC. Then, they were randomly divided into two groups (n = 10/group), according to the aging procedure: thermal cycling group and water storage group. Before and after aging procedures, specimens were x-rayed with an aluminum step-wedge (11 steps, 1 mm thick each) and three dental slices (1 mm thick). The radiopacity was evaluated by means of optical density, which was measured using ImageJ software. The values were converted into millimeters of aluminum with a logistic regression calibration curve. The data were analyzed by one-way ANOVA and Tukey post-hoc test (α = 0.05). RESULTS: In the thermal cycling group, RelyX Luting 2, RelyX U200, and Panavia F2.0 showed a statistically significant reduction in radiopacity (p < 0.05). In the water storage group, all cements showed a significant reduction in radiopacity (p < 0.05), and RelyX Luting 2 and Panavia F2.0 performed below the desired ISO 4049 standard. CONCLUSIONS: The radiopacity of luting cements can decrease after aging, especially after 1-year water storage.

Evaluation of marginal leakage after mechanical fatigue cycling of composite inlays luted with different cements.

This in vitro study evaluated the marginal microleakage of composite inlays luted with 3 different cement systems. The null hypothesis was that the luting materials would not influence dye penetration, showing the same degree of microleakage. Thirty-six sound molars were selected, mesio-occlusodistal cavities were prepared, and the teeth were randomly divided into 3 groups (n = 12). Composite resin inlay restorations were made and cemented using a dual-curing resin cement (Calibra), a light-curing flowable composite (Charisma Flow), or a self-adhesive resin cement (RelyX Unicem). The restored teeth were subjected to fatigue cycles and immersed in 0.5% basic fuchsin dye for 24 hours. Two orthogonal cuts were made to enable evaluation of dye penetration at the cervical and occlusal margins. The sections were evaluated with a 4-point scale ranging from 0 (no penetration) to 3 (penetration up to the cavity floor [occlusal margins] or axial wall [cervical margins]). The Calibra and Charisma Flow groups showed greater microleakage, notably at the cervical margins, whereas RelyX Unicem specimens showed the least dye penetration. Significant differences were found between the Calibra and Charisma Flow groups and between the Charisma Flow and RelyX Unicem groups (P < 0.05). No statistically significant differences were detected between the Calibra and RelyX Unicem groups. The microleakage associated with the flowable composite was significantly greater than that associated with both resin cements, results that discourage its use for luting of Class II composite inlays.

[Paradigm shift in conservative dentistry: the end of the amalgam era]. / Paradigmaváltás a fogmegtartó kezelésben: az amalgámkorszak vége.

Dental amalgam has been used for more than 150 years due to its beneficial mechanical properties and durability in dentistry. In the past and to date, many questions about amalgam restorations have arisen, especially regarding the mercury content, which has been the subject of global disputes. By presenting the past and present of the 'amalgam issue', the aim of our paper is to display the current position of international literature. This summary is based on the publications in the PubMed database, the guidelines of the Council of European Dentists. Although the use of dental amalgam is widespread, concerns have been raised about the adverse effect on human health and the environment, focusing on its heavy metal pollution during waste treatment. In 2017, the European Union (EU) adopted the so-called Mercury Regulation, based on the United Nations Minamata Convention on Mercury, the recommendations of which are presented in the present review. This Regulation includes the requirement for EU Member States to develop a national action plan for the phase-down of amalgam. The feasibility plan for complete phase-out may be guaranteed by 2030. The authors discuss the advantages and disadvantages of possible amalgam alternatives by presenting glass-ionomers and resin-based composites. In the future, more material research programmes and long-term follow-up studies are necessary. In addition to several global health organizations, the Council of European Dentists also draws attention to prevent dental caries, expecting to reduce the number of restorations. Orv Hetil. 2018; 159(42): 1700-1709.

Enamel wear by antagonistic restorative materials under erosive conditions.

OBJECTIVES: This study aimed to analyse loss of enamel worn against composite, leucite glass ceramic or enamel antagonists under non-erosive and alternating or simultanuous erosive-attritive conditions. MATERIALS AND METHODS: Flat human enamel specimens were loaded (1 Hz, 300 g loading weight, each subgroup n = 12) with antagonists made from a hybrid-composite (Z250, 3 M Espe), a nano-composite (Filtek Supreme XTE, 3 M Espe), leucite glass ceramic (IPS Empress CAD LT, Ivoclar Vivadent) or enamel. Specimens were either submitted to mechanical loading in mineral solution (60 s) or to loading under alternating or simultaneous erosive conditions. For alternating erosion-attrition, specimens were eroded by citric acid (pH 2.6, 60 s) and then loaded with the respective antagonist for 60s. For simultaneous erosion-attrition, specimens were loaded with the respective antagonist while being immersed in citric acid (pH 2.6, 60 s). After each cycle, specimens were stored in water for 1 h. After 18 cycles, enamel loss was calculated profilometrically and statistically analysed by two-way ANOVA and Tukey's post-hoc tests (p < 0.05). RESULTS: Enamel loss (µm, mean ± standard deviation) was significantly highest for simultaneous erosion-attrition (ceramic 9.4 ± 1.1, hybrid-composite 8.3 ± 0.7, nano-composite 7.8 ± 1.2, enamel 7.4 ± 0.8) followed by alternating erosion-attrition (ceramic 3.5 ± 0.5, hybrid-composite 2.1 ± 0.8, nano-composite 1.0 ± 0.2, enamel 2.5 ± 0.7) and attrition in mineral solution (ceramic 0.5 ± 0.3, hybrid composite 0.3 ± 0.1, nano composite 0.1 ± 0.2, enamel 0.1 ± 0.1). Ceramic antagonists resulted in significantly higher loss than the remaining antagonistic materials when alternating or simultaneous erosion-attrition was performed. CONCLUSION: Erosive conditions had a massive impact on enamel worn against different antagonistic materials, with simultaneous erosive-attritive conditions being more detrimental than alternating erosive-attritive conditions. CLINICAL RELEVANCE: Enamel wear by antagonistic restorative materials is significantly influenced by erosive conditions.

Failure rate of single-unit restorations on posterior vital teeth: A systematic review.

STATEMENT OF PROBLEM: No knowledge synthesis exists concerning when to use a direct restoration versus a complete-coverage indirect restoration in posterior vital teeth. PURPOSE: The purpose of this systematic review was to identify the failure rate of conventional single-unit tooth-supported restorations in posterior permanent vital teeth as a function of remaining tooth structure. MATERIAL AND METHODS: Four databases were searched electronically, and 8 selected journals were searched manually up to February 2015. Clinical studies of tooth-supported single-unit restorative treatments with a mean follow-up period of at least 3 years were selected. The outcome measured was the restorations' clinical or radiological failure. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, the Cochrane Collaboration procedures for randomized control trials, the Strengthening the Reporting of Observational Studies in Epidemiology criteria for observational studies, 2 reviewers independently applied eligibility criteria, extracted data, and assessed the quality of the evidence of the included studies using the American Association of Critical Care Nurses' system. The weighted-mean group 5-year failure rates of the restorations were reported according to the type of treatment and remaining tooth structure. A metaregression model was used to assess the correlation between the number of remaining tooth walls and the weighted-mean 5-year failure rates. RESULTS: Five randomized controlled trials and 9 observational studies were included and their quality ranged from low to moderate. These studies included a total of 358 crowns, 4804 composite resins, and 303582 amalgams. Data obtained from the randomized controlled trials showed that, regardless of the amount of remaining tooth structure, amalgams presented better outcomes than composite resins. Furthermore, in teeth with fewer than 2 remaining walls, high-quality observational studies demonstrated that crowns were better than amalgams. A clear inverse correlation was found between the amount of remaining tooth structure and restoration failure. CONCLUSIONS: Insufficient high-quality data are available to support one restorative treatment or material over another for the restoration of vital posterior teeth. However, the current evidence suggests that the failure rates of treatments may depend on the amount of remaining tooth structure and types of treatment.

Noninvasive approach to esthetic rehabilitation of conoid anterior teeth.

Several factors, including anomalies of shape, color, or size, or positioning of the teeth, may interfere with smile esthetics. A 26-year-old woman was dissatisfied with the esthetics of her maxillary lateral incisors, which had defective composite resin restorations with alterations of color and shape. The aim of this article is to present a step-by-step description of the technique used to fabricate esthetic restorations for the conoid maxillary lateral incisors with a minimum of dental preparation. The successful outcome demonstrates the importance of correct planning for successful 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.

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.