A new species of Liparis (Orchidaceae, Epidendroideae, Malaxidinae) from the Bosque de Protección Alto Mayo, San Martín, Peru.

Liparisaltomayoënsissp. nov. is described, illustrated, and tentatively assigned to the Neotropical section Decumbentes on the basis of its branching, prostrate rhizomes and upright stems bearing several leaves. Vegetatively, the new species is distinguished by its short, upward stems bearing 3-6 leaves, these with undulate, translucent margins and reticulate, prominent veining on the upper surface. Florally, it is distinctive in the labellum with fleshy basal one-half provided with a central, rounded cavity limited on each side by a prominent, bilobulate ridge and apically by a lunate ridge, and membranaceous, trilobulate apical one-half deflexed ca. 90°. In contrast with other species of section Decumbentes, in which fruit formation is infrequent, in L.altomayoënsis a high proportion (⁓50-100%) of flowers develop into a fruit; in some flowers the pollinaria rotate and contact the stigma, apparently resulting in at least facultative self-pollination. The main differences among the six species of L.sectionDecumbentes hitherto known are contrasted in a dichotomous key. The new species is known only from three populations located in the Bosque de Protección Alto Mayo, on the Amazonian slope of the Andes in northeastern Peru but appears to be under no foreseeable threats.

ResumenLiparisaltomayoënsissp. nov. es descrita, ilustrada y asignada tentativamente a la sección neotropical Decumbentes con base en sus rizomas postrados, ramificados y tallos ascendentes portando varias hojas. Vegetativamente, la nueva especie se distingue por sus tallos ascendentes cortos con 3­6 hojas, éstas con márgenes undulados, translúcidos y venación reticulada prominente en la superficie superior. Floralmente, es distintivo su labelo con la mitad basal carnosa, provista de una cavidad central redondeada que está limitada a cada lado por una cresta bilobulada prominente y apicalmente por una cresta lunada, y la mitad apical del labelo membranácea, trilobulada y deflexa ca. 90°. En contraste con otras especies de la sección Decumbentes, en las que la producción de frutos es infrecuente, en L.altomayoënsis una alta proporción (⁓50­100%) de las flores produce fruto; en algunas flores los polinarios rotan y contactan el estigma, aparentemente resultando en autopolinización al menos facultativa. Las diferencias principales entre las seis especies de L. sección Decumbentes conocidas hasta ahora se contrastan en una clave dicotómica. La nueva especie se conoce solamente de tres poblaciones localizadas en el Bosque de Protección Alto Mayo, en la vertiente amazónica de los Andes en el noreste de Perú, pero no parece estar sujeta a amenazas previsibles.

Evaluation of Microbial Leakage at Implant Abutment Interfact for Different Implant Systems: An In Vitro Study.

Two-stage implant systems result in gaps and cavities between implant and abutment that can act as a trap for bacteria and thus possibly cause inflammatory reactions in the peri-implant soft tissues. These gaps between the components are inevitable, and their clinical significance has so far been mostly neglected by both manufacturers and clinicians. This study is thus intended to evaluate microbial leakage at implant abutment interface in different implant systems. Four different systems, the Nobel tri-channel, the Nobel conical, the Equinox, and the Straumann, were used for this study. One microliter of a fresh broth suspension of Streptococcus mutans was added to the implant fixture (implant body). The implant was immersed in fresh heart brain infusion and was incubated at 37° for 48 hours. After incubation, 10 µL of the broth was made as lawn culture on sterile agar and the colonies were counted and recorded as colony-forming units per milliliter. Statistical tests were carried out on SPSS software and tests included analysis of variance (ANOVA) and P value was derived using Tukey's honestly significant difference post hoc test. After incubation, results were analyzed by evaluating the microbial leakage from each sample and it was observed that Nobel tri-channel had the least amount of microbial leakage and Equinox had maximum microbial leakage. The difference among all implant systems was statistically significant P < 0.05. The study concluded that least micro-leakage was found in the Nobel tri-channel whereas maximum microbial leakage was present in Equinox and Straumann.

Antimicrobial study of cast post and its surface modification with nanoparticle.

A cast post is a one-piece unit that is custom fabricated for the tooth at the dental laboratory. Traditional extracts such as neem and green tea have good antimicrobial and antioxidant activity against pathogens. The empty canal space may provide a suitable environment for promoting bacterial growth. The main aim of the study is to find the antimicrobial activity of the cast post coated with the nanoparticle. Prepared cast post was coated with prepared green tea and neem-mediated zinc oxide (ZnO) nanoparticles. Culture is done in agar media where control is noncoated post and another is nanoparticle coated post was implanted in the agar media. The zone of inhibition was noted and statistical analysis was done. The maximum zone of inhibition found on Candida albicans (19.333 2.081) followed by Enterococcus faecalis (14.000 3.605), and Streptococcus mutans (12.666 2.516). Green tea and neem-mediated ZnO nanoparticle showed good antimicrobial activity against the tester microorganism. Cast post coated with nanoparticles has been proved to be important as it is helpful in the prevention of origin and spread of infection around the canal and through the apical foramen.

Polyether ether ketone - As an alternative biomaterial for Metal Richmond crown-3-dimensional finite element analysis.

Aim: This study was aimed to analyze the stress generation and distribution for "polyether ether ketone (PEEK)" and metal cobalt-chromium (Co-Cr) at different locations of the tooth using finite element analysis (FEA), when they are casted-off as "Richmond crowns." Materials and Methods: The model of the tooth was designed using "computer-aided design/computer-aided manufacturing" followed by generating the "Mesh" of the tooth to analyze the stress caused by applying vertical and oblique loads of 100N and 40N, respectively, in cubical nodes for both PEEK and metal endodontic post-based Richmond crown. The "3-dimensional von Mises criteria" was used to compare stresses of both elements using FEA. The material properties for each component were designated by respective modulus of elasticity and Poisson's ratio. The statistical test of the stress generation in various locations of PEEK and Metal (Co-Cr) Richmond crown was done by independent t-test. Results: From the FEA analysis of Richmond crown, it is evident that maximum stress was generated by "Metal" of about 66.418 MPa when compared to "PEEK" (15.826 MPa). "PEEK Richmond crown" produced minimal stress on the tooth and the other surrounding regions than "Metal Richmond crown" with a statistically significant difference (P < 0.05). Conclusion: The results proved that the "Metal Richmond crown" postsystem had a tendency to produce more stress on the tooth and the other surrounding regions than the PEEK. The FEA proved the pros of using "PEEK post Richmond crown," which is a big boon for the modern era dentistry.

Three-dimensional-Printed Malo Bridge: Digital Fixed Prosthesis for the Partially Edentulous Maxilla.

Screw-retained implant restorations have an advantage of predictable retention, retrievability, and lack of potentially retained subgingival cement. However, a few disadvantages exist such as need for precise placement of the implant for optimal and esthetic location of the screw access hole and obtaining passive fit. Malo bridge with customization of abutment can establish a precise patient's gingival architecture. It is the most esthetically advanced form of fixed prosthodontic rehabilitation for complete and partially edentulous patients. This prosthesis is combined with three-dimensional (3D)-printed computer-aided design and computer-aided manufacturing technology to gain the precise fit and added esthetics. It also has advantages such as elimination of screw access openings, makes it possible to remove and repair the fractured porcelain of the individual crown without removing the whole structure, excellent precision, avoids casting errors, light weight, reduced complexity of laboratory procedures, high definition of morphology, and time-consuming. This case report presents replacement of partially edentulous maxilla using 3D-printed Malo bridge.

Attitudes of students and teachers on cheating behaviors: descriptive cross-sectional study at six dental colleges in India.

Cheating behavior has been a serious problem in dental institutions across the globe. Attitudes of dental students have an impact on the quality of health care provided to their patients. This descriptive cross-sectional study had the following objectives: to assess and compare the attitudes of dental students and teachers about cheating behaviors, to assess students' opinions of various justifications for their cheating, and to assess teachers' attitudes towards various punishment options for cheating behaviors. The study sample consisted of 1,261 undergraduate students and 131 teachers from six randomly chosen dental colleges in Tamil Nadu State, India. A closed-ended questionnaire was used for respondents to rate the seriousness of cheating behaviors. The students were asked to justify their cheating behavior, and the teachers were asked to assign punishments for the cheating behaviors. The attitudes of students and teachers on the cheating behaviors were analyzed and compared using a Pearson chisquare test, with a confidence interval of 95 percent and significance level of p≤0.05. The attitudes of the teachers and students were statistically different in two cheating behaviors: copying during exams and helping other students copy in exams. The two main justifying reasons students gave for cheating behavior were to pass the exam (59.3 percent) and to obtain a better grade (31.3 percent). Warning and counseling to help the students reassess their moral values were preferred to penalizing punishments by the teachers.