Gokhan Akgungor

Simultaneous Replacement of Maxillary Central Incisors with CEREC Biogeneric Reference Technique: A Case Report.

Biogeneric Reference Technique (BRT) of the CEREC 3D v.3.8 software is an effective technique for single anterior ceramic crowns because it provides computer-controlled match of the tooth form to the contralateral tooth. BRT also enables the fabrication of two or more anterior all-ceramic crowns simultaneously. This clinical report demonstrates the clinical application of BRT for designing and milling two central incisors in one appointment using a single optical impression. After completing the virtual design of the first central incisor, it was copied and a mirror image was created. The second central incisor was designed using this replicated image and therefore a computer-controlled symmetry was obtained. The crowns were milled from monolithic feldspathic ceramic blocks and adhesively luted with dual-cured resin cement following dentin conditioning. At the two-year follow-up appointment, the restorations were intact, no adverse effects were noted, and the resultant appearance was highly satisfactory for the patient. A step-by-step protocol is described from design to cementation of these restorations.Background and aims. An ideal root canal filling material should completely seal the entire root canal space and block communication between the root canal system and its surrounding tissues; it should also be nontoxic, noncarcinogenic, non-genotoxic, biocompatible, insoluble in tissue fluids and dimensionally stable. Bonding to dentin is a promising property, which can prevent leakage and improve the sealing ability of root canal filling materials. Resilon was developed and rec-ommended initially because the existing rootcanal filling materials did not bond to root canal dentin. Since its introduction in 2004, numerous reports have been published regarding various aspects of this material. The aim of this literature review is to present investigations regarding Resilons physical and chemical properties and leakage studies. Materials and methods. A review of the literature was performed by using electronic and hand searching methods for Resilon from May 2004 to April 2012. Results. There are many published reports regarding Resilon. The searchshowed that Resilon is composed of a parent polymer, polycaprolactone or Tone, which is a biodegradable aliphatic polyester, with filler particles consisting of bioactive glass, bismuth oxychloride and barium sulfate. It possesses some antibacterial and antifungal properties. It is a promising material for root canal filling. Despite the presence of numerous case reports and case series regarding these applications, there are few designed research studies on clinical applications of this material. Resilon has some drawbacks such as high cost. Conclusion. Resilon seals well and is a biocompatible material. However, more clinical studies are needed to confirm its efficacy compared with other materials.

Does the Translucency of Novel Monolithic CAD/CAM Materials Affect Resin Cement Polymerization with Different Curing Modes?: Effect of Ceramic Translucency on Resin Cement Curing

PURPOSE The translucency of CAD/CAM blocks influences the polymerization efficiency of resin cement used underneath. The aim of this study is to evaluate the influence of the translucency parameters (TPs) of current monolithic CAD/CAM blocks on the microhardness of light-cured or dual-cured resin cement. MATERIALS AND METHODS 100 specimens were prepared from five types of CAD/CAM blocks (Mark II, Suprinity, Enamic, e.max, Ultimate), and their TP values were measured by spectrophotometry; 100 resin cement specimens (Duolink) were cured underneath five ceramic specimen groups by indirect LED light for 40 seconds with dual-cure (with catalyst) and light-cure (without catalyst) polymerization modes. Control group resin cement specimens (n = 20) were cured with both polymerization modes by direct LED light without any ceramic disc, making 120 resin cement specimens in total. The specimens were then stored in a dry environment for 24 hours before measurement of the polymerization depth with a digital micrometer. Vickers hardness measurements were performed at different resin cement sections. The results were statistically analyzed with 1-, 2-, and 3-way ANOVA, Students t-test and Tukeys HSD test (α = 0.05). RESULTS The highest TP values occurred for Suprinity and Ultimate, whereas the lowest TP value occurred for Enamic (p < 0.01). The depth of cure and Vickers hardness values changed proportionally with TP value. In all specimens, dual polymerization provided higher depth of cure and Vickers hardness values than those obtained using light polymerization (p < 0.01). In all specimens except Enamic, the hardness value differences between the sections were statistically insignificant (p > 0.05). In Enamic, the hardness values for both polymerization types decreased significantly in the deeper sections (p < 0.01). CONCLUSIONS Lower depth of cure was observed as the amount of transmitted light decreased in the investigated materials. In clinical practice, light-cured resin cements may result in inadequate polymerization for ceramic materials with lower TP values. Zirconia-reinforced lithium silicate and nanoceramic resins may be reliable restorative materials for a restoration with both optimal esthetics and sufficient mechanical strength resulting from proper polymerization.

Influence of MDP Content in Different Resin Cements and Zirconia Primers on Ceramic-Resin Cement Bond Strength

ABS TRACT Objective: Evaluating the influence of MDP in different primers and resin cements on microtensile bond strength to zirconia ceramic after thermal cycling. Material and Methods: 6 zirconia blocks (23x20x10 mm) were prepared and divided into 3 groups (n=2) according to the following surface treatments: (1) air-particle abrasion with 50 μm Al2O3 particles, (2) air-particle abrasion and zirconia primer application, (3) air-particle abrasion and MDP-containing primer mixture application. Composite resin blocks were bonded to the pretreated zirconia surfaces using 2 different resin cements. Zirconia-composite blocks were cut to microbars with a cross-section of 1.0 ± 0.2 mm. The samples were thermocycled and microtensile bond strength tests were performed. Samples were evaluated under optical microscope. Data were analyzed with 1and 2-way ANOVA and Tukey multiple comparison tests (α=.05). Results: MDP based resin cements provided similar bond strengths (p>0.05) to air-particle particle abraded and primer pretreated zirconia surfaces. BisGMA based resin cements provided statistically higher bond strengths (p<0.05) to primer pretreated zirconia surfaces than air-particle particle abrasion alone. No statistically significant differences (p>0.05) were detected between the zirconia primers used. Conclusion: MDP containing resin cements or primers increase the bonding strength of zirconia. When using fixed partial dentures with zirconia substructures, clinicians are advised to use either primers or resin cements with MDP, if not both.

Occlusal Surface Reconstruction with Chairside Ceramic Onlay Using CEREC Biogeneric Design Mode: Case Report

The occlusal design of dental restorations should stay in harmonic relation to the remaining dentition. In CAD/CAM dentistry, the occlusion is generated by the CAD software based on standard morphologies from the dental database. An automated adaptation process of this standard morphology to an individual clinical situation is difficult and leading to manual adaptation of the proposal with design tools. The new biogeneric software of the chairside CAD/CAD system (CEREC) automatically collects optic measurement of the preparation side including mesial and distal neighbor teeth and antagonist teeth to design a restoration with a patient specific occlusal morphology. This clinical report demonstrated a case, which was treated with ceramic onlay designed and milled with CEREC system used in biogeneric design mode. Digital impression of the preparation was taken with the intraoral camera. Buccal scan,technique was used for taking the occlusal record. Preparation and antagonist images were automatically correlated by software and a virtual articulator was created. After trimming the virtual model, preparation margins were outlined with the automatic margin finder option of the software and then the insertion axis of the restoration was determined. The biogeneric restoration proposal was then automatically seated to the virtual model and desired changes were performed with the design tools of the software. The restoration was milled from feldspathic ceramic block.