Search results for "Crown"
showing 10 items of 324 documents
Convergence angles of all-ceramic full crown preparations performed in Dubai private practice
2018
Background This study aimed to determine the degree of taper and total occlusal convergence angles (TOC) for all-ceramic bonded crown preparations carried out by private practitioners in Dubai, UAE. Material and Methods A convenience sample of all-ceramic crown preparations carried out by private dental practitioners were scanned (Carestream CS 3500) from casts and the digital images assessed. The degree of taper was measured on the axial walls of each crown preparation and the bucco-lingual and mesio-distal convergence angles subsequently calculated. Results A total of 154 dentists prepared a total of 206 crown preparations (72 anterior, 134 posterior). The mean convergence angles mesio-di…
The effect of dental chair light exposure duration on shear bond strength of orthodontic brackets : an in vitro study
2018
Background The purpose of this study is to determine if the duration of exposure to the halogen overhead dental chair light has an effect on shear bond strength (SBS) of metal orthodontic brackets. Material and Methods One hundred twenty extracted human lower incisor teeth were divided into six groups (n=20/group). Each group was assigned a predetermined duration of exposure to the halogen dental chair light, set at a fixed distance, before being cured. Light exposure times of 0 minutes (Group 1-Control), 1 minute (Group 2), 2.5 minutes (Group 3), 5 minutes (Group 4), 10 minutes (Group 5), and 15 minutes (Group 6) were tested. Each tooth was subjected to an exclusion criteria examination, s…
Full mouth functional and aesthetic rehabilitation of a patient affected with hypoplastic type of amelogenesis imperfecta
2020
The management of Amelogenesis imperfecta often poses a challenge for the dentists. It not only includes aesthetic and functional rehabilitation of the patient, but also requires a positive rapport building with the patient due to psychosocial issues. The treatment plan is driven by patient demands, age, cost-affordability, severity of the disease and the presenting condition. The present case report elucidates step by step management of a 20 year-old female who presented with generalized hypersensitivity, intermittent pain associated with multiple decayed posterior teeth, poor dental aesthetics and anterior deep bite. The management consisted of endodontic treatments in all teeth, crown le…
Altered passive eruption (APE) : a little-known clinical situation
2010
Gummy smile constitutes a relatively frequent aesthetic alteration characterized by excessive exhibition of the gums during smiling movements of the upper lip. It is the result of an inadequate relation between the lower edge of the upper lip, the positioning of the anterosuperior teeth, the location of the upper jaw, and the gingival margin position with respect to the dental crown. Altered Passive Eruption (APE) is a clinical situation produced by excessive gum overlapping over the enamel limits, resulting in a short clinical crown appearance, that gives the sensation of hidden teeth. The term itself suggests the causal mechanism, i.e., failure in the passive phase of dental eruption, tho…
Management of a crown-root fracture : a novel technique with interdisciplinary approach
2018
Anterior teeth with subgingival fractures require a complex treatment plan that addresses biologic, functional and aesthetic factors. This case report describes the management of a crown-root fractured maxillary left central incisor. An interdisciplinary approach was used to restore the tooth due to the complex nature of the treatment. Orthodontic extrusion was performed to move the fracture line above the alveolar bone and periodontal surgery to recontour the altered gingival margin. Finally, the incisor was restored performing a root canal retreatment with a fiber post and a full ceramic crown. The treatment resulted in secured periodontal health and good aesthetics. Key words:Crown-root …
Analyzing the enforcement of a high-spin ground state for a metallacrown single-molecule magnet
2016
We have studied element-selective magnetic properties of the hetero- and homometallic metallacrowns $\mathrm{Cu}{(\mathrm{II})}_{2}[12\ensuremath{-}{\mathrm{MC}}_{YN(Shi)}\ensuremath{-}4]$ ($Y=\text{Cu}$, Fe, in short ${\mathrm{CuCu}}_{4}$ and ${\mathrm{CuFe}}_{4}$). These metallacrowns comprise four Fe or Cu ions surrounding a central Cu ion. Using x-ray magnetic circular dichroism we have probed local symmetries, electronic configuration, orbital and spin magnetic moments of the magnetic ions. The ratio between the Cu and Fe moment of $\ensuremath{-}0.11$ is independent of temperature in the range of 15 K to 90 K. The Cu moment shows antiparallel to the Fe moment. For ${\mathrm{CuCu}}_{4}…
Influence of core color on final shade reproduction of zirconia crown in single central incisor situation ? An in vivo study
2020
Background A lot of shaded zirconia blocks are being introduced into the market. Their effect on the final shade of the restoration is yet uncertain. Material and methods Twenty-four zirconia crowns were fabricated for 8 patients who needed to restore a single maxillary central incisor, and divided into 3 groups according to the color and type of the zirconia (Zr) used (white Zr core, colored Zr core, and monolithic high translucency (ht) Zr crowns). Using Easyshade spectrophotometer, delta E color difference was calculated between fabricated crown and adjacent tooth. The ΔEs obtained were assessed based on 1.6 ΔE which represented the color difference that could not be detected by the huma…
Influence of substrate design for in vitro mechanical testing
2019
Background: The goal of this study was to evaluate the influence of dental substrate simulator material, and the presence of root and periodontal ligament on the stress distribution in an adhesively-cemented monolithic crown.Material and methods: Five (5) 3D models according to the substrate simulator material and shape were modeled with CAD software for conducting non-linear finite element analysis (FEA): Tooth with and without periodontal ligament - subgroup "pl" (groups Tooth+pl and Tooth-pl), machined tooth in epoxy-resin with and without pulp chamber - subgroup "pc" (ER+pc and ER-pc) and simplified epoxy-resin substrate without pulp chamber and roots (SiER). Next, adhesively-cemented m…
Marginal bone loss around cement and screw-retained fixed implant prosthesis
2018
Background Implant-supported fixed restorations are considered as the standard treatment for replacement of missing teeth. These can be either screw or cement retained. The success or failure of implant restorations depend upon amount of marginal bone loss (MBL). The present study is to determine the MBL around cement and screw-retained implant prosthesis and to determine various predictors of the MBL. Material and Methods A retrospective charts review was conducted at the dental clinics, Aga Khan University Hospital, Karachi from February 2017 to June 2017 in which 104 implants restorations were assessed using periapical radiographs. MBL was calculated at baseline and at 12 months and the …
Immediate placement of single implant simultaneously with immediate loading in a fresh socket associated to periapical infection: a clinical case rep…
2015
Early restoration of the masticatory function, phonatory and aesthetics is some of the current goals of the therapy based on endosseous implants. Facing the classic protocols of implant insertion, which recommend a period of several months between extraction and implant placement, alternatives have been developed that demonstrate that immediate implant placement after tooth extraction permits adequate osseointegration, even in those cases where there is a periapical disease. The immediate restoration of implants after placement is a possibility where aesthetic requirements are high. This article presents a case with immediate implant placement and immediate loading of a first upper premolar…