PubMed ID (PMID): 22324221Pages 297-307, Language: English, GermanLehmann, Karl Martin / Kasaj, Adrian / Ross, Armin / Willershausen, Ines / Schmidtmann, Irene / Scheller, Herbert / Staedt, HenningPurpose: To evaluate whether a three-dimensional (3D) optical method currently used for the production of dental restorations could be applied to the simultaneous evaluation of the height and width of periodontal recessions, and determine the reproducibility and accuracy of the method for evaluating periodontal recession.
Materials and Methods: The height and width of periodontal recessions scratched onto stone replicas were recorded using a 3D optical method, a periodontal probe, and a caliper.
Results: No difference was found between measurements obtained using the methods tested (p > 0.05). However, measurements using the 3D optical method showed the highest reproducibility.
Conclusion: The 3D optical method allowed the accurate and reproducible evaluation of the height and width of periodontal recessions. The next step should be the development of fully automated soft-tissue monitoring software to increase time savings.
Keywords: recession, diagnosis, evaluation, computerbased, reproducibility, accuracy
PubMed ID (PMID): 22324222Pages 309-319, Language: English, GermanSimon, James F. / de Rijk, Waldemar G. / Hill, Jennifer / Hill, NathanielPurpose: This study measured the bond strength of the self-adhesive resin cements and a bonded resin cement for crowns bonded to extracted teeth with preparations having a total taper greater than 30 degrees. A crown pull-off test was used with direction of pull along the path of insertion. The CAD/CAM system Cerec was used to create crowns with the pull-off loop as an integral part of the crown structure.
Materials and Methods: One hundred extracted human molars were prepared for all-ceramic crowns with a 1.5-mm shoulder, greater than 30-degree axial wall convergence, a flat occlusal surface and 3 to 5 mm occlusal/ gingival height. All-ceramic crowns were cemented with five different self-adhesive cements (Rely X Unicem, Maxcem Elite, BisCem, SmartCem 2, and G-Cem) and one bonded resin cement (Multilink). For four cements (excluding GCem and Multilink) there were 2 groups, one with HF etching and one without ceramic surface treatment. The crowns were then subject to tensile stress until either the crown fractured or the crown was lifted off from the tooth.
Results: For several cements, the bond strength exceeded the tensile strength of the all-ceramic crown; thus, the crown fractured, leaving the cemented part of the crown on the tooth. The effect of ceramic surface etching was not statistically significant at p = 0.05; however, for each cement, the treated crowns showed a lower coefficient of variance (COV). For this study, the COV ranged from 24.9 % to 97.9 %. Loads ranged from 41.3 to 190.3 N.
Conclusion: Some of the new self-etching resin cements can create bonds to non-retentive crown preparations that are stronger than the strength of a ceramic crown; however, these high bond strengths may not be able to be achieved consistently.
Keywords: retention, resin cements, all-ceramic crowns, Cerec
PubMed ID (PMID): 22324223Pages 321-334, Language: English, GermanSiotia, Jaya / Gupta, Sunil Kumar / Acharya, Shashi Rashmi / Saraswathi, VidyaRadiographic examination is essential in diagnosis and treatment planning in endodontics. Conventional radiographs depict structures in two dimensions only. The ability to assess the area of interest in three dimensions is advantageous. Computed tomography is an imaging technique which produces three-dimensional images of an object by taking a series of two-dimensional sectional X-ray images. DentaScan is a computed tomography software program that allows the mandible and maxilla to be imaged in three planes: axial, panoramic, and cross-sectional. As computed tomography is used in endodontics, DentaScan can play a wider role in endodontic diagnosis. It provides valuable information in the assessment of the morphology of the root canal, diagnosis of root fractures, internal and external resorptions, pre-operative assessment of anatomic structures etc. The aim of this article is to explore the clinical usefulness of computed tomography and DentaScan in endodontic diagnosis, through a series of four cases of different endodontic problems.
Keywords: computed tomography, DentaScan, endodontic diagnosis, radiography
PubMed ID (PMID): 22324224Pages 335-342, Language: English, GermanFrank, ElmarModern dental implantology is characterized by prosthetically oriented implant planning and the use of appropriate planning and navigation tools. Most of these systems utilize 3D imaging technology, allowing the clinician to perform three-dimensional planning and placement of the desired restoration.
PubMed ID (PMID): 22324225Pages 343-352, Language: English, GermanKurbad, AndreasThe optimization of technical procedures in dental practices and laboratories is a matter of time. Today, professionals are under high cost pressure, particularly in the health care industry. Process automation not only offers us the potential to save time and money, but also contributes to quality assurance. Digital veneering of CAD/CAM zirconia bridge framework structures from zirconium dioxide (ZrO2) materials affords such an opportunity.
