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Concept: CAD/CAM Dentistry

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SUMMARY Fracture resistance of inlays and onlays may be influenced by the quantity of the dental structure removed and the restorative materials used. The purpose of this in vitro study was to evaluate the effects of two different cavity preparation designs and all-ceramic restorative materials on the fracture resistance of the tooth-restoration complex. Fifty mandibular third molar teeth were randomly divided into the following five groups: group 1: intact teeth (control); group 2: inlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent AG, Schaan, Liechtenstein); group 3: inlay preparations, zirconia ceramic (ICE Zirkon, Zirkonzahn SRL, Gais, Italy); group 4: onlay preparations, lithium-disilicate glass-ceramic (IPS e.max Press); and group 5: onlay preparations, zirconia ceramic (ICE Zirkon). The inlay and onlay restorations were adhesively cemented with dual polymerizing resin cement (Variolink II, Ivoclar Vivadent AG). After thermal cycling (5° to 55°C × 5000 cycles), specimens were subjected to a compressive load until fracture at a crosshead speed of 0.5 mm/min. Statistical analyses were performed using one-way analysis of variance and Tukey HSD tests. The fracture strength values were significantly higher in the inlay group (2646.7 ± 360.4) restored with lithium-disilicate glass-ceramic than those of the onlay group (1673.6 ± 677) restored with lithium-disilicate glass-ceramic. The fracture strength values of teeth restored with inlays using zirconia ceramic (2849 ± 328) and onlays with zirconia ceramic (2796.3 ± 337.3) were similar to those of the intact teeth (2905.3 ± 398.8). In the IPS e.max Press groups, as the preparation amount was increased (from inlay to onlay preparation), the fracture resistance was decreased. In the ICE Zirkon ceramic groups, the preparation type did not affect the fracture resistance results.

Concepts: Touring car racing, FIA, Teeth, Analysis of variance, Crown, Dental restoration, CAD/CAM Dentistry, Inlays and onlays

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Alveolar distraction osteogenesis (ADO), a novel bone augmentation technique, is gaining acceptance in restoring the vertical bone discrepancy between the transplanted graft and the residual alveolar bone after mandibular reconstruction. This case series presents the outcomes of ADO in fibula-reconstructed mandibles rehabilitated with dental implants, with an emphasis on clinical indications, surgical protocol, clinical outcomes, histologic evidence, and complications.

Concepts: Implants, Dental implant, Dentistry, Oral and maxillofacial surgery, Osseointegration, CAD/CAM Dentistry

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Background The authors describe our current practice of computer-aided virtual planned and pre-executed surgeries using microvascular free tissue transfer with immediate placement of implants and dental prosthetics.Methods All patients with ameloblastomas treated at New York University (NYU) Medical Center during a 10-year period from September 2001 to December 2011 were identified. Of the 38 (36 mandible/2 maxilla) patients that were treated in this time period, 20 were identified with advanced disease (giant ameloblastoma) requiring aggressive resection. Reconstruction of the resultant defects utilized microvascular free tissue transfer with an osseocutaneous fibular flap in all 20 of these patients.Results Of the patients reconstructed with free vascularized tissue transfer, 35% (7/20) developed complications. There were two complete flap failures with consequent contralateral fibula flap placement. Sixteen patients to date have undergone placement of endosteal implants for complete dental rehabilitation, nine of which received immediate placement of the implants at the time of the free flap reconstruction. The three most recent patients received immediate placement of dental implants at the time of microvascular free tissue transfer as well as concurrent placement of dental prosthesis.Conclusions To our knowledge, this patient cohort represents the largest series of comprehensive computer aided free-flap reconstruction with dental restoration for giant type ameloblastoma.

Concepts: Implants, Computer-aided design, Dental implant, Dentistry, Oral and maxillofacial surgery, Periodization, Free flap, CAD/CAM Dentistry

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Routine reconstruction of subtotal defects of the mandible and orthopedic rehabilitation supported by dental implants is achieved by means of detailed planning and lasts over a year. This article shows the outcomes of single-stage surgical treatment and immediate orthopedic rehabilitation performed with the help of preoperative virtual computer simulation. 3D investigation of pathological and donor sites, virtual simulation of tumor resection, positioning of the dental implants into fibula, virtual flap bending and transfer, virtual bending of fixing reconstruction plates, and fabrication of navigation templates and bridge prosthesis supported by dental implants were done preoperatively. The surgery included tumor resection, insertion of dental implants into fibula, elevation of fibula osteocutaneous free flap, rigid fixation within recipient site, and immediate loading by bridge orthopedic device. On 10-month follow-up, functional and esthetic results were asses as reasonable. Radiography showed dental implants to be integrated and positioned appropriately. We found that successful rehabilitation of the patients with extensive defects of the jaws could be achieved by ablative tumor resection, dental implants insertion prior to flap elevation guided by navigation templates, further osteotomy, modeling of the flap based on navigation template, flap transfer, and rigid fixation within recipient site by prebended plates, with application of prefabricated prosthesis.

Concepts: Implants, Prosthetics, Computer simulation, Dental implant, Dentistry, Oral and maxillofacial surgery, CAD/CAM Dentistry, Nobel Biocare

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Preclinical dental students must demonstrate aptitude in the preparation of teeth for treatment with several types of fixed dental prostheses. The optimal sequence of instruction and examination of these crown preparations in preclinical fixed prosthodontics is unknown. The aim of this study was to determine if grading scores by faculty and students were affected by changing the sequence of crown type preparations. Practical exams of two successive student cohorts (n=89 in 2014; n=92 in 2015) at one U.S. dental school using three crown preparations (full cast, porcelain fused to metal, and all-ceramic) in different order were analyzed by faculty grades and student self-assessment. All of the models indicated that the sequence in which the crown type preparations were taught did have an effect on the grades. The 2014 cohort had overall higher grades and particularly higher grades for the all-ceramic crown preparations. Evaluation scores were affected by the sequence in which the different crown type preparations were taught and tested. Although the overall results suggested that students may perform better if the all-ceramic crown preparation is taught last, this tendency may differ between years.

Concepts: Crown, Dental restoration, Restorative dentistry, CAD/CAM Dentistry, Bridge, Prosthodontology, Inlays and onlays, Fixed prosthodontics

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Presenting patients with the opportunity to restore their smiles using dental implants, which is a reliable and widely accepted technique, is highly recommended. Therefore, a correct clinical judgment and a, consequently, dental implant treatment planning is a central component of a good practice of implant dentistry. Moreover, to the oral clinician be able to make better decisions and reach a more accurate clinical judgment, it is necessary continuing professional development being, this development, an essential professional activity for dentists that intend planning implant treatments. Thus, considering that a correct “clinical judgment is a central component of the practice of implant dentistry”, this paper intends to discuss some issues related to the impact that professional formation might have on patient-centered outcomes. By describing three examples of inaccurate treatment decisions through the analysis of radiographic images (two panoramic radiographies and 1 periapical X-ray) illustrating complete failure in dental implant rehabilitations, the discussion will address the importance of a good professional formation that enables clinicians to reach accurate decisions and make clinical judgments supported by evidence-based knowledge.

Concepts: Implants, Dental implant, Dentistry, Oral and maxillofacial surgery, Osseointegration, CAD/CAM Dentistry

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Adhesive cementation is a useful procedure not only for cementing restorations onto teeth but also for attaching new ceramic restorations to existing restorations to improve their esthetics and/or function. This clinical report presents a technique for modifying an existing nonsatisfactory implant-supported fixed dental prosthesis by means of adhesively cemented veneers and onlays bonded to the pre-existing metal-ceramic surface with resin cement. This modification may avoid the replacement of the fixed dental prosthesis, reducing both treatment costs and time while fulfilling the patient’s demands.

Concepts: Prosthetics, Crown, Dental restoration, Restorative dentistry, CAD/CAM Dentistry, Imperative programming, Inlays and onlays, Self-modifying code

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The aim of this retrospective study was to compare the performance of implants placed after alveolar distraction osteogenesis (ADO) or autogenous onlay bone grafting (AOBG) based on implant survival, peri-implant bone resorption, and clinical parameters.

Concepts: Cohort study, Bone fracture, Surgery, Implants, Orthopedic surgery, Dental implant, Oral and maxillofacial surgery, CAD/CAM Dentistry

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By increasing the number of replaced tooth with dental implants, the number of poorly positioned implants is also increased. In this article we present our experience about a 48-year-old female who was referred to our department for resolving prosthetic problem regarding two malpositioned implants inserted in the upper jaw. The interocclusal space was insufficient and the two adjacent implants had excessive buccal angulation. To overcome these problems, segmental osteotomy of the alveolar bone containing two implants has been done. After palatal and apical repositioning of the bone block, rigid fixation was performed using a 4-hole miniplate and four 5mm monocortical screws. Two weeks after the procedure, a conventional fixed prosthesis was constructed with regard to the esthetic and functional aspects. During the two-year follow-up, the patient was satisfied with the result, and there were no complications, such as alveolar bone necrosis, marginal bone loss, implant failure or infection.

Concepts: Mouth, Implants, Prosthetics, Dental implant, Dentistry, Oral and maxillofacial surgery, Osseointegration, CAD/CAM Dentistry

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Indirect restorations are an important treatment in dental practice, but long-term survival studies are lacking.

Concepts: Dental implant, Dentistry, Dental restoration, Restorative dentistry, CAD/CAM Dentistry, Bridge, Dental porcelain