Bond strength and feasibility, Ni–Cr alloys, Recycled alloys
DOI: 10.5005/jp-journals-10019-1240 |
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Jhansi R, Reddy AV, Prasad KS, Kiran YS, Sundeep D. A Comparative Assessment of Flexural Bond Strength of Ni–Cr Metal–Ceramic Alloy on Repeated Castings. Int J Prosthodont Restor Dent 2019; 9 (3):70-76.
Aim: The present work is aimed to evaluate and compare the metal–ceramic bond strength and clinical feasibility of three commercially available Ni–Cr alloys with different compositions before and after recasting. The hypothesis of this experiment is to evaluate the effect of the recasting of base metal alloys in the physical and chemical properties of alloys, which in turn affect the metal–ceramic bond strength. Materials and methods: In the present experiment, we considered 60 Ni–Cr metal samples, which were divided into group I and group II with every 30 samples. Group I consists of 30 samples fabricated with 100% new alloy, and group II consists of 30 samples fabricated with 100% recycled alloy. Groups I and II are further divided into three subgroups IA, IB, IC and IIA, IIB and IIC on the basis of three brands of Ni–Cr alloy as NDN as (A), soft alloy as (B) and superbond as (C) with each of 10 samples. Metal sprues and buttons obtained after casting of group I samples were used as a recast alloy for the fabrication of group II samples. Results: The flexural bond strength of the fabricated metal–ceramic samples was subjected to three points bending test in a universal testing machine. The obtained values were statistically analyzed using one-way analysis of variance and post hoc Tukey analysis. The morphological studies are the stereomicroscopic examination of all the samples revealed alloy–metal oxide disjunction failure. Conclusion: The mean flexural bond strength for all the groups was above the minimum requirement by American Dental Association (ADA) specification no. 38 and ISO specification 9693. The mean bond strength of group I samples is found to be greater than the group II samples. The soft alloy and superbond have the highest mean bonds when compared among the samples fabricated with 100% new alloy and 100% recycled alloy. Superbond and soft alloy are followed by former and later, and NDN is found to be least for both types. The soft alloy has more reduction in metal–ceramic bond strength in group II (samples fabricated with 100% recycled alloy) when compared to group I.
Aim: To evaluate the relationship of tooth color with skin color and eye color based on gender in young Indian adults. Materials and methods: Two hundred subjects (100 males and 100 females) in the age range of 20–35 years. Skin color was categorized using skin shade tab (aviance beauty palette); eye color was visually assessed; and L*, C* and h* values of tooth were measured using Vita EasyShade Intraoral Dental Spectrophotometer (Advance 4.0)™. Statistically significant differences between the groups were compared using one-way analysis of variance (ANOVA) and Tukey's test. Pearson correlation was used to see the linear relation between the variables. Results: Significant correlation was observed between skin color and value, eye color and chroma, age, and value in males and females (p < 0.05). Conclusion: It was concluded that hue, value, and chroma of tooth are partially dependent on skin color, eye color, age, and gender. This study points out that no single parameter should be used while considering the selection of fixed anterior restoration in full-mouth rehabilitation cases as well as for a new set of complete dentures to an edentulous patient, instead various factors need to be kept in mind.
DOI: 10.5005/jp-journals-10019-1239 |
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Giovanni-Battista M, Ugo C, Paolo T, Giovanni C, Luigi R, Roberto C. Customized vs Conventional Abutments in Healing Fresh Extraction Dental Sockets on Maxillary Anterior Teeth. Int J Prosthodont Restor Dent 2019; 9 (3):82-87.
Aim: The aim of the present retrospective study on fresh socket implants in esthetic region was to compare customized vs standard healing abutments, evaluating alveolar bone assessment. Materials and methods: Postextractive sockets underwent immediate dental implant placement without filling the voids between the implant surface and socket wall. Width of the alveolar ridge following implant placement with or without customized abutment mimicking the look of the extracted tooth was measured on three-dimensional radiographs before and 3 years after surgery. The statistic is performed with a level of significance of 0.05. Results: In a split-mouth analysis, 22 patients were enrolled with a total of 44 selected maxillary dental implants: 14 incisives, 14 canines, and 16 premolars. An implant survival rate of 100% was reported for all implants after 36 months. 3 years after the implant placement, loss in bone width was registered both for the standard group (−2.18 ± 0.59 mm) and for the custom group (−0.08 ± 0.22 mm), even if dimensional change of the alveolar ridge following the healing procedure appeared in the custom group to be not significant with respect to the standard group. Significant differences were found between groups irrespective of tooth type (p ≤ 0.0001), and among subgroups related to the tooth type (incisor vs both canine and premolar, with p ≤ 0.0124). Conclusion: Custom procedure might help provide a seal over the surgical site to protect the coagulum and to support natural emergence profile for optimal final restorative contours, and in doing so promoting socket volume maintenance.
Advances in technology and material development in dentistry and increased use of social media in recent years have raised the esthetic and cosmetic expectations of patients. Today's dentist should, therefore, be able to blend the concepts of ethics and esthetics. Examination of esthetic analysis by dividing into sections, such as facial analysis, dentolabial analysis, dental analysis, and phonetic analysis; and knowing these criteria well will provide a great advantage to the clinician in terms of planning and meeting the patient expectations.
Smile is a person's greatest beauty asset, but various dental diseases like spacing, diastema, discoloration and staining of teeth can adversely affect smile. Literature suggests several approaches for correction of such defects, such as orthodontic intervention, direct and indirect restorative treatments, or their combination. Indirect restorations have been used as a successful option for beautifying smile. But the success of these procedures is based on the correct diagnosis, treatment planning, technique and restorative material used. This article describes three cases with generalized spacing between teeth, diastema and generalized fluorosis which were rehabilitated using lithium disilicate indirect restorations. Digital smile design software was used for diagnosis and treatment planning. These results were used as a guide for designing and fabrication of laminate veneers using CAD/CAM.
Bonding to enamel has been shown to provide reliable results, and thus conservative tooth reduction is key to the success of the ceramic bonded veneers. The diagnostic wax is the first available to evaluate disparities between current and ideal tooth measurements. The mock-up provides the patient with a physical perception of the size and shape of the proposed veneers. The use of reduction guides assists the clinician in evaluating the specific amount of tooth structured to be removed during the preparation. This article demonstrates a conservative approach to tooth preparation combining different tooth reduction guides. Long-term success of the restoration requires following well-defined protocols for restorative material selection, conservative tooth preparation, and bonding ceramic protocols.