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Aim: The present study aimed to evaluate on a comparative basis the vertical marginal fit between conventionally casted, direct metal laser sintered (DMLS), and milled computer-aided design/computer-aided manufacturing (CAD-CAM) one-piece metal framework supported by five implants using one-screw test and screw resistance test. Settings and Design: This is an in vitro study. Materials and Methods: Five implants were placed parallel to one other in a Styrofoam master model. A total of 30 implant-supported screw-retained superstructures were manufactured using three techniques, i.e., conventionally casted, milled, and sintered. To evaluate the vertical marginal discrepancy, screw resistance test, and one-screw test were used, and measurements were made using a stereomicroscope. Statistical Analysis Used: The data was analysed using two statistical tests, i.e., ANOVA and the post hoc Bonferroni test. Results: On evaluating the frameworks using one-screw test, the mean vertical misfit value at the terminal implant for the control group was 292.58 ± 15.46µm, for conventionally casted framework 398.41 ± 21.13 µm, for DMLS 343.44 ± 24.73 µm, and for CAD-CAM was 304.03 ± 14.23 µm, whereas the average misfit values at four implants on applying screw resistance test were 1268.65 ± 84.24 (control), 1774.88 ± 67.70 (casted), 1508.02 ± 62.19 (DMLS), and 1367.29 ± 81.87 (CAD-CAM). The average misfit values on two implants using screw resistance test were 635.02 ± 57.33 for the control group; for conventionally casted, it was 879.75 ± 35.93; for (DMLS) framework, it was 761.51 ± 32.85; and for milled CAD-CAM framework, it was 687.07 ± 42.17 µm. Conclusion: The mean vertical marginal discrepancy, when compared with control, was least in milled CAD-CAM frameworks, followed by sintered DMLS and conventionally casted frameworks. Hence, according to the present study, CAD/CAM technique is recommended to achieve maximum marginal fit in full mouth screw-retained implant-supported FDPs.

Asunto(s)

Implantes Dentales , Adaptación Marginal Dental , Prótesis Dental de Soporte Implantado , Diseño Asistido por Computadora , Tornillos Óseos

RESUMEN

Summary. Prosthetic rehabilitation of a completely edentulous patient is no more confined to replacement of missing teeth. Long span of edentulism and ageing leads to loss of support of the facial musculature, which is of great concern in treating completely edentulous patients. Flaccid facial musculature eventually leads to sunken cheeks and unesthetic appearance, causing a negative impact on psychological well-being of the patient. The use of conventional complete dentures can restore the loss to some extent, but in some cases, additional support is required. The present clinical report exemplifies the use of magnet-retained detachable maxillary cheek plumper prosthesis in a completely edentulous patient with sunken cheeks.

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AIM: The aim of this work was to evaluate stress distribution on implants in All-on-Four situation with varying distal implant angulations (30°,40°,45°) and varying cantilever lengths (4 mm, 8 mm, 12 mm, 16 mm) in atrophic maxilla using finite element analysis. SETTING AND DESIGN: A in vitro study, finite element analysis. MATERIALS AND METHODOLOGY: Three-dimensional finite element model of an edentulous maxilla restored with a prosthesis supported by four implants was reconstructed to carry out the analysis. Three different configurations, corresponding to 3 tilt degrees of the distal implants (30°, 40°, and 45°) were subjected to 4 loading simulations. STATISTICAL ANALYSIS USED: The results of the simulations obtained were evaluated in terms of Von Mises equivalent stress levels at the bone-implant interface. RESULT: From a stress-level viewpoint, the 45° model was revealed to be the most critical for peri-implant bone. In all the loading simulations, the maximum stress values were always found at the neck of the distal implants. With increasing distal implant tilt, cantilever length reduces depending on the quality of bone. At 30° angulation of distal implant a maximum cantilever length of 16 mm may be given if the quality of bone is D3 but only 8 mm cantilever may be recommended if bone quality is D4. At 40° angulation, 16 mm in D3 bone and 0 mm in D4 bone whereas at 45° angulation, it reduces to 12 mm in D3 bone and no cantilever is recommended with D4 bone. CONCLUSION: The 45° tilt induced higher stress values at the bone-implant interface, especially in the distal aspect, than the other 2 tilts analyzed. Stress values increased with increased cantilever length which was further influenced by the distal implant tilt and the quality of the bone.

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AIM: This study aims to evaluate the effect of lithium disilicate glass-ceramic liner, silicon dioxide based liner, and glass-ceramic interlayer on the shear bond strength (SBS) of a commercially available veneered zirconia block and to study fractographic behavior of the samples using universal testing machine, scanning electron microscope (SEM). SETTING AND DESIGN: In vivo - comparative study. MATERIALS AND METHODS: 60 samples were fabricated from VITA (vita zahnfabrik. Bad sackingen, Germany) zirconia discs. Samples were divided into 4 groups with 15 samples each. First is the control group, second is lithium disilicate glass-ceramic liner group, third is silicon dioxide based liner, and fourth is glass-ceramic interlayer group. SBS of samples was recorded using universal testing machine. Samples were further analyzed for fractographic behavior using SEM. STATISTICAL ANALYSIS USED: One Way ANOVA test, and Chi-Square test. RESULTS: The intergroup comparison of mean SBS (Mpa) was done using the post hoc Bonferroni test. The mean SBS (Mpa) was significantly more among lithium disilicate and glass-ceramic interlayer groups in comparison to silicon dioxide-based liner group. Fractographic analysis was done using the Chi-square test. CONCLUSION: It was concluded that maximum SBS was obtained for lithium disilicate liner. Maximum adhesive failures were found with lithium disilicate liner, and silicon dioxide-based liner group showed cohesive failures.

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BACKGROUND: A pediatrician is supposed to be one of the first clinician who sees a child from infancy through adolescence. This study was carried for pediatricians serving in medical colleges and tertiary hospitals in Bhubaneswar City, Odisha, India. MATERIALS AND METHODS: A questionnaire was distributed among 30 pediatricians serving in various medical colleges and tertiary hospitals in Bhubaneswar City area. It consisted of questions regarding knowledge of pediatricians on the awareness of detrimental effects of long-term liquid medicaments use on oral cavity, including delivery of oral hygiene instructions and regular dental checkup. The data as obtained were subjected to statistical analysis using Statistical Package for the Social Sciences (SPSS) software, version 17.0, for Microsoft Windows (Chicago, Illinois). RESULTS: The results showed that there is a good amount of awareness among the pediatricians working in medical colleges in Bhubaneswar regarding pediatric liquid medication and their ill effects on teeth. Most pediatricians considered age and body weight of the child (87%). Sixty five percent of pediatricians were aware that pediatric liquid medication (PLM) can cause dental caries. Ninety five percent of them were aware of PLMs with sugar substitutes are available in market. CONCLUSION: The overall awareness among the pediatricians regarding the ill effects of pediatric liquid medications on teeth is satisfactory.

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BACKGROUND: Denture hygiene is of utmost importance to maintain the dentures as well as the underlying tissues in appropriate health. Various denture cleansers as well as denture-based materials have evolved in the market; however, the effect of denture cleansers on different types of denture-based materials has not been very well documented. AIM: The purpose of this in vitro study was to evaluate and compare the surface roughness in heat-cured denture-based resin and injection-molded resin system as affected by two commercially available denture cleansers for a period of 15, 30, and 45 days. METHODOLOGY: A standardized metal die was fabricated to make 120 denture-based resin discs of uniform dimensions. The samples of heat-cured denture-based resin and injection-molded thermoplastic denture-based resin were immersed in the two denture cleansing solutions for a period of 15, 30, and 45 days, respectively. The surface roughness was evaluated by surface profilometer TR200. The data were subjected to statistical analysis and the comparison of quantitative data was done using unpaired t-test and repeated-measures ANOVA test. RESULTS: The surface roughness values (Ra) of heat cured denture base resin samples when immersed in two denture cleansers were 0.22 µm at 0 days, 0.27 and 0.29 µm at 15 days, 0.29 and 0.31 µm at 30 days, 0.30 and 0.31 µm at 45 days whereas for injection moulded samples surface roughness values were 1.31 & 1.27 µm at 0 days, 1.46 & 1.66 µm at 15 days, 1.50 & 1.69 µm at 30 days, and 1.50 & 1.69 µm at 45 days. CONCLUSION: The surface roughness (Ra) increased significantly in injection-molded polyamide denture-based resin samples when immersed in both the denture cleansers. Whereas, heat-cured denture-based resin samples did not reveal any significant surface changes at the various time intervals. Hence, the use of denture cleansers is questionable in thermoplastic resins.

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The aim of this article is to present the clinical application of immediate implant placement with L-PRF and immediate prosthetic loading in anterior esthetic region. A 24-year-old healthy female patient reported with a chief complaint of poor esthetics in the upper front tooth region with retained deciduous teeth. On oral examination, there were retained deciduous teeth (52, 53, and 63) with congenitally missing permanent successors. The retained deciduous teeth were extracted, and immediate implant placement was done in the extraction sockets along with L-PRF membranes in one surgical session under local anesthesia. Immediate temporization was performed with composite crowns on immediately placed dental implants. After 3 months of the healing period, the final implant-level impressions were made and the temporary composite crowns were replaced with the final zirconia porcelain crowns. A 12-month follow-up was made, and satisfactory esthetic and functional results were obtained.

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AIM AND OBJECTIVES: Acrylic teeth are used for fabrication of dentures. Debonding of tooth - denture base bond is routine problem in dental practice. The aim of this study was to comparatively evaluate failure load of acrylic resin denture teeth bonded to three different heat resin. MATERIALS AND METHODS: Four groups were created out of test samples central incisors (11). Group I: Control, whereas Group II, Group III and Group IV were experimental groups modified with diatoric hole, cingulum ledge lock and Teeth modified with both diatoric hole and cingulum ledge lock, respectively. These test specimens with 3 teeth (2 central [11, 21] and 1, lateral [12] incisors) positioned imitating arrangement of teeth in the conventional denture, prepared by three different heat cure materials (DPI, Trevalon, Acralyn-H). A shear load was applied at cingulum of central incisor (11) at 130° to its long axis using universal tester at a cross head speed of 5 mm/min until failure occurred. Failure load test was conducted and statistical analysis was performed using SPSS 16 software package (IBM Company, New York, U.S). RESULTS: Highest failure load was seen in Group IV specimens, prepared by Trevalon but did not significantly differ from that of DPI. CONCLUSION: The failure load of bonding denture teeth to three different heat cure materials was notably affected by modifications of ridge lap before processing. The specimens with a combination of diatoric hole and cingulum ledge lock, prepared by Trevalon showed highest failure load but did not significantly vary from that of DPI. The control group prepared by Acralyn-H showed lowest failure load but did not significantly differ from that of DPI.

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AIM AND OBJECTIVE: Acrylic teeth separates from the denture base and remains a major worry in day-to-day routine dental procedure. The present study was conducted to comparatively evaluate different mechanical modifications of acrylic teeth on bond strength between Lucitone 199 heat cure resin and cross-linked teeth. MATERIALS AND METHODS: The test specimens, central incisors (21) were demarcated into four groups. Group 1 was the control group, whereas Group 2, Group 3, and Group 4 were experimental groups modified with round groove, vertical groove, and T-shaped groove, respectively. The preparation of masterpiece was done by aligning the long axis of the central incisor teeth at 45° to the base of a wax block (8 mm × 10 mm × 30 mm), with ridge lap surface contacting the base. These test specimen (21) was prepared by Lucitone 199 heat cure resin. Evaluation of bond strength of all the specimens was done using universal tester (materials testing machine). Shapiro-Wilk Test, one-way analysis of variance (ANOVA), and Bonferroni test were done to do statistical investigation. RESULTS: Group 1 specimens prepared by Lucitone 199 heat cure resin showed the lowest bond strength and Group 4 specimens prepared with T-shaped groove packed with Lucitone 199 exhibited the highest bond strength. CONCLUSION: The bond strength between Lucitone 199 heat cure resin and cross-linked teeth was increased when mechanical modifications was done on denture teeth. The specimens prepared with T-shaped groove packed with Lucitone 199 heat cure resin showed the highest bond strength followed by Group 3, Group 2, and lastly Group 1 prepared by Lucitone 199 heat cure resin.

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Wearing complete dentures can be an extremely uncomfortable experience for the people with Xerostomia. Various treatment modalities have been suggested in the literature to overcome the problem of xerostomia in complete denture patients. Incorporating reservoirs containing salivary substitutes, into dentures, is one of these treatment modalities. This paper presents case report of a patient suffering from xerostomia who was successfully treated with a new form of reservoir dentures. This new split denture technique resulted in a reservoir denture that provided good lubrication of the oral tissues, was easily cleaned by the wearer and was produced from routine denture materials. Details of its design, construction and other potential applications are also presented.

RESUMEN

Denture Adhesives are commonly used by denture wearers to enhance the retentive ability of their dentures however, little is known about the efficacy of these materials. To compare the retentive ability of three different commercially available denture adhesives. To find out the best available denture adhesive material. An in vitro investigation to evaluate the retentive ability of three commercially available denture adhesive powders and two adhesive pastes was conducted. The adhesion and cohesion that developed between the glass surface and acrylic resin samples when the various materials were interposed between them was evaluated by means of a testing apparatus. Denture adhesives increase the adhesion of resin samples to the glass surface. Fixon powder showed the highest resistance to dislodgement. The paste forms were found to be more retentive. Denture adhesives when used in combination with synthetic saliva showed the maximum value.