RESUMO
Congenital partial hypodontia is a commonly encountered disorder, presenting a challenge for adolescents seeking treatment, as existing options often come with drawbacks. Among these options, the Maryland Bridge stands out for its accessibility and notable benefits in terms of both strength and aesthetics. This article explores the merits of this treatment modality, supported by a detailed case study demonstrating its successful application. An 18-year-old patient was referred to our hospital with a complaint of missing bilateral maxillary incisors. Upon clinical examination, it became apparent that the orthodontic treatment was done and exhibited the absence of bilateral incisors in the upper arch. Subsequent diagnosis confirmed congenital partial hypodontia. To address the missing teeth, a treatment plan centered around the use of a Maryland Bridge was devised. One of the persistent challenges faced by restorative dentists is devising solutions for congenitally missing lateral incisors. Despite the availability of numerous therapeutic alternatives, none are without their limitations. However, the outcome of the rehabilitation in this case proved to be notably aesthetically pleasing, effectively fulfilling the intended purpose. As a result, this article advocates for the Maryland Bridge as a viable option for patients facing similar dental challenges.
RESUMO
The contact mode high-speed atomic force microscope (AFM) operates orders of magnitude faster than conventional AFMs. It is capable of capturing multiple frames per second with nanometre-scale lateral resolution and subatomic height resolution. This advancement in imaging rate allows for microscale analysis across macroscale surfaces, making it suitable for applications across materials science. However, the quality of the surface analysis obtained by high-speed AFM is highly dependent upon the standard of sample preparation and the resultant final surface finish. In this study, different surface preparation techniques that are commonly implemented within metallurgical studies are compared for samples of SAF 2205 duplex stainless steel. It was found that, while acid etching and electrolytic etching were optimal for the low resolution of optical microscopy, these methods were less suited for analysis by high resolution high-speed AFM. Mechanical and colloidal silica polishing was found to be the optimal method explored, as it provided a gentle etch of the surface allowing for high quality topographic maps of the sample surface.
RESUMO
Conservation of natural tooth structure precipitated the emergence of resin-retained fixed partial dentures. The weakest link in this modality is the bond between resin cement and alloy of the retainer. Various alloy surface treatment have been recommended to improve alloy-resin bond. This in vitro study was carried out to observe changes in the Nickel-Chromium alloy (Wiron 99, Bego) surface following sandblasting or electrolytic etching treatment by scanning electron microscope (SEM) and to evaluate the shear bond strength of a resin luting cement bonded to the surface treated alloy. 80 alloy blocks were cast and divided into four groups of 20 each. In groups-A & B, the test surfaces were treated by sandblasting with 50 and 250 µm sized aluminium oxide particles respectively. In groups-C & D, the test surfaces were first treated by sandblasting with 50 and 250 µm sized aluminium oxide particles respectively followed by electrolytic etching. Test surfaces were observed under SEM at 1,000× magnification. Two alloy blocks of each group were luted together by a resin luting cement (Rely X, 3M) and their shear bond strength was tested. The mean shear bond strength in MPa of groups-A to D were 6.44 (±0.74), 8.18 (±0.51), 14.45 (±0.59) and 17.43 (±1.20) respectively. Group-D showed bond strength that is more than clinically acceptable bond strength. It is recommended that before luting resin-retained fixed partial dentures, the fitting surface of the retainer should be electrolytically etched to achieve adequate micromechanical retention.