Influence of two natural cross-linkers on microtensile bond strength durability ­ An in vitro study / Influência de dois reticuladores naturais na durabilidade da resistência de união à microtração ­ Um estudo in vitro

Objective: to investigate the effect of two natural cross-linkers on microtensile bond strength (µTBS) and evaluate their influence on the durability of the resin dentin bonds. Material and Methods: the Moringa oleifera and Centella asiatica plant extracts were qualitatively tested with high-performance thin layer chromatography (HPTLC) for the presence of phenols. The phenolic content ranged from 27 to 30 gallic acid equivalents (GAE), µg/mg of dry weight. After etching, two concentrations (5% and 1%) of these two extracts were prepared and used as pretreatment liners on dentin. They were applied for a min. After restoration with resin composite, dentin resin beams were prepared. The study groups were 5% Moringa, 1% Moringa 5% Centella 1% Centella, and control (without cross-linker application). For each group, half of the samples underwent µTBS testing after 24 hours, while the remaining half were immersed in artificial saliva to assess the bond's longevity after 6 months of ageing. Statistical analysis was performed using one-way ANOVA followed by Tukey's post hoc test. Results: both 5% and 1% Moringa showed a significant difference (p<0.05) compared to the other groups at both intervals. However, after ageing, the specimens in the control and 1% Centella groups resulted in a significant decrease in µTBS. Conclusion: overall, both concentrations of Moringa (5% and 1%) were effective in stabilising the bond during both intervals.(AU)

Objetivo: investigar o efeito de dois reticuladores naturais na resistência de união (µTBS) à microtração e avaliar sua influência na durabilidade da adesão da resina à dentina. Material e Métodos: extratos das plantas Moringa oleifera e Centella asiatica foram qualitativamente testados através de cromatografia em camada fina de alta performance (HPTLC) para a presença de fenóis. O conteúdo fenólico alcançou entre 27 a 30 equivalentes de ácido gálico (GAE), µg/mg de peso seco. Após o condicionamento, duas concentrações (5% e 1%) dos extratos foram preparadas e utilizadas como forros de pré-tratamento em dentina. Eles foram aplicados por um minuto. Após a restauração com resina composta, palitos de dentina e resina foram preparados. Os grupos foram 5% Moringa, 1% Moringa, 5% Centella, 1% Centella e controle (sem aplicação de reticulador). Para cada grupo, metade das amostras foram submetidas ao teste µTBS após 24 horas, enquanto a outra metade foi imersa em saliva artificial para avaliar a longevidade adesiva após 6 meses de envelhecimento. Foi realizada análise estatística através de ANOVA 1-fator, seguido do teste post hoc de Tukey. Resultados: ambas as concentrações de 5% e 1% de Moringa demonstraram diferença significativa (p<0.05) comparadas aos outros grupos em ambos os intervalos. No entanto, após o envelhecimento, os espécimes dos geupos controle e 1% de Centella resultaram em uma redução significativa de µTBS. Conclusão: no geral, ambas as concentrações de Moringa (5% e 1%) foram efetivas em estabelecer a adesão em ambos os intervalos (AU)

The 100 most cited articles in prosthodontic journals: A bibliometric analysis of articles published between 1951 and 2019.

STATEMENT OF PROBLEM: Bibliometric studies to determine the characteristics of the most cited articles in prosthodontic journals are lacking. PURPOSE: The purpose of this study was to analyze the characteristics of the 100 most cited articles in prosthodontic journals between 1951 and 2019. MATERIAL AND METHODS: The Google Scholar database was used to retrieve the list of journals with titles containing the term "Prosthodontic" or "Prosthetic." Twelve journals were filtered, and of these, only 8 were related to dentistry and hence were included in the study. A search was then performed for each of the selected journals under "Publication Name," and articles were arranged by the category "Times Cited." The 100 most cited articles from the 8 journals were selected and analyzed with regard to journal name, year of publication, authors and their country, type of study, and area of research. RESULTS: The 100 most cited articles were published between 1958 and 2013, with the numbers of citations ranging between 2368 and 343. The journal with the largest number of the articles cited was the "Journal of Prosthetic Dentistry" with 72 articles, followed by the "International Journal of Prosthodontics" with 25 articles. The decade with most articles published was the 1990s with 33 articles. Many of the authors of most cited articles were from the United States or Sweden. Most articles reported reviews (35 articles), followed by experimental studies (34); the most commonly cited area of research was related to dental implants. CONCLUSIONS: This bibliometric analysis of the 100 most cited articles revealed interesting facts about scientific progress in the field of prosthodontics.

Antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.

STATEMENT OF PROBLEM: Conventional spray and the immersion disinfection of irreversible hydrocolloid impression materials may lead to dimensional changes. PURPOSE: The purpose of this in vitro study was to investigate the antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles. MATERIALS AND METHODS: The antimicrobial activity and properties of 2 commercially available irreversible hydrocolloid impression materials were evaluated after incorporating varying concentrations of silver nanoparticles. Antimicrobial activity was determined using the disk diffusion method. The gel strength, permanent deformation, flow, and gelation time were measured according to American Dental Association specification #18. Analysis of variance was used to identify the significant differences within and across the groups (α=.05). RESULTS: Adding silver nanoparticles to irreversible hydrocolloid impression materials resulted in superior antimicrobial activity without adversely affecting their properties. Adding silver nanoparticles to Zelgan significantly increased the gel strength compared with the control group, except at 5 wt%. However, the gel strength of Tropicalgin was unaffected except at 5 wt%. An increase in the permanent deformation was found with the incorporation of silver nanoparticles in both Zelgan and Tropicalgin. The flow of Zelgan increased with the incorporation of silver nanoparticles, whereas a decrease in the flow of Tropicalgin was observed at 1 wt% and 2 wt%. An increase in the gelation time of both Zelgan and Tropicalgin was observed with the incorporation of silver nanoparticles. CONCLUSIONS: Based on this in vitro study, silver nanoparticles can be incorporated into irreversible hydrocolloid impression materials as antimicrobial agents without adversely affecting their properties.

Assessment of thickness of palatal masticatory mucosa and maximum graft dimensions at palatal vault associated with age and gender - a clinical study.

BACKGROUND: Periodontitis is a multifactorial inflammatory disease which leads to alveolar bone loss, followed by exposure of root surfaces, which results in an unaesthetic appearance. Palatal masticatory mucosa is widely used as a donor tissue for root coverage procedures, to achieve an aesthetic appearance and to meet patient's needs. Obtaining sufficient volume of tissue without injuring the vessels is necessary. AIM: Purpose of this study was to determine thickness of palatal masticatory mucosa in association with age and gender in healthy subjects who were aged 14-59 years. MATERIALS AND METHODS: Thirtysix healthy subjects were included under two groups (aged 14-29 years and 30-59 years). Each group consisted of 9 males and nine females. Transgingival probing was done by using a UNC-15 (University of North Carolina) periodontal probe under LA (local anaesthesia) and measurements were taken from 15 different sites on palatal masticatory mucosa. Maximum available length and height of the palatal vault were also measured. All measurements were made by using a Boley gauge to the nearest millimetre. RESULTS: Students t-test was used to determine the difference in mucosal thickness between two groups. Two-way ANOVA test was used to measure the height of palatal vault between the groups. The results showed that younger age group had thinner palatal masticatory mucosa of thickness which was between 2.3 mm to 2.65 mm and that younger females had thinner mucosa than males. The mean height which was measured from second premolar area to the second molar area was significantly greater in men (14.03 mm) than in women (13.25 mm). CONCLUSION: Palatal masticatory mucosa was thicker in older age group than in younger age group and it was thin in females as compared to that in males. The most appropriate donor site for carrying out grafting procedures is distal canine to mid palatal aspect of 1st molar area, with minimum height of 5 mm to 8 mm in the premolar area in all cases.

Immunolocalization of CD34 Positive Progenitor Cells in Diabetic and Non Diabetic Periodontitis Patients - A Comparative Study.

BACKGROUND: Little research has been documented to determine the CD34 positive cells in healthy periodontium, chronic periodontitis and in chronic periodontitis with diabetes mellitus individuals. AIM: The aim of the present study was to evaluate and compare the CD34 positive progenitor cells of the gingiva in patients with healthy periodontium, chronic periodontitis and chronic periodontitis with Diabetes Mellitus. MATERIALS AND METHODS: A total number of 75 patients were divided into 3 groups which included Group I (healthy periodontium), Group II (chronic periodontitis) and Group III (chronic periodontitis with diabetes mellitus). Periodontal examination included Plaque index, Gingival index, Gingival bleeding index, Probing pocket depth and Clinical attachment levels. Gingival biopsies were collected from each participant and they were fixed in formalin embedded in paraffin which was later subjected to immunohistochemical procedure with anti-CD34 (a stemness marker). T-Test and Regression analysis (R-square) was used to analyse the data. RESULTS: The mean number of CD34 positive cells were higher in group III (5.71±1.97) compared to Group chronic periodontitis group I (4.98± 2.08) and II (4.48± 1.24). CONCLUSION: Although CD34 is a non specific stemness marker, results suggest that there is a significant difference in the number of CD34 positive progenitor cells between Group II and Group III but no significant difference was observed between Group I, II and Group I, III.

Local and systemic effects of unpolymerised monomers.

Methyl methacrylate (MMA), a widely used monomer in dentistry and medicine has been reported to cause abnormalities or lesions in several organs. Experimental and clinical studies have documented that monomers may cause a wide range of adverse health effects such as irritation to skin, eyes, and mucous membranes, allergic dermatitis, stomatitis, asthma, neuropathy, disturbances of the central nervous system, liver toxicity, and fertility disturbances.