Time-dependent reflection and surface temperatures during CO 2 laser irradiation of dental hard tissues with 100-μs pulses

Author(s):  
Wolf D. Seka ◽  
Daniel Fried ◽  
John D. B. Featherstone ◽  
Richard E. Glena
1999 ◽  
Vol 17 (5) ◽  
pp. 223-226 ◽  
Author(s):  
MOZAMMAL HOSSAIN ◽  
YUKIO NAKAMURA ◽  
YUICHI KIMURA ◽  
MITSUHIRO ITO ◽  
YOSHISHIGE YAMADA ◽  
...  

2011 ◽  
Vol 53 (4) ◽  
pp. 348-355
Author(s):  
Thakare Eesha ◽  
Chaudhary Minal ◽  
Gawande Madhuri ◽  
Wadhwan Vijay ◽  
Gadbail Amol

2016 ◽  
Vol 40 (2) ◽  
pp. 152-155 ◽  
Author(s):  
TE Shishniashvili ◽  
NN Suladze ◽  
VV Margvelashvili

Objectives: To study the influence of environmental pollution on the mineralization of dental hard tissues by using biosubstrates: teeth and hair. :Study design: At the first stage epidemiological survey was conducted in polluted and less polluted areas of Tbilisi (Georgia). We studied 525 children aged 3 and 4 years. Caries prevalence and intensity was defined by the methodology of World Health Organization. At the second stage the chemical elements content was studied in hair and teeth hard tissues of 24 children by X - ray fluorescent spectroscopy method. Results: The prevalence of dental caries in the polluted region was 46%, caries intensity − 1.92 (± 2.842). In the less polluted region prevalence was 37%, caries intensity − 1.47 (± 2.571). These data are statistically reliable (p < 0.05). The study of hair and tooth tissues showed that the toxic elements (Pb, Hg, Sn, Ti) content in these tissues was higher in environmentally unfavorable than in favorable conditions. Conclusion: Hair and dental tissues can be used as indicators of environmental pollution. Our survey showed that toxic elements content in dental hard tissues was higher and the level of essential elements was less in polluted than in less polluted areas of Tbilisi.


2019 ◽  
Vol 23 (3) ◽  
pp. 132-140
Author(s):  
Enea Bitri ◽  
Lucian Petcu ◽  
Gabriela Mocanu ◽  
Doina Paula Balaban

Summary Background/Aim: The chemical nature of soft drinks is acidic, so they possess the capacity to cause hard tissue erosion. The aim of this study is to assess the potentially erosive effect linked to pH and titratable acidity of some common soft drinks on dental hard tissues in prolonged time exposure. Material and Methods: Seven types of soft drinks in Romanian market were selected for this study. The pH and Titratable acidity were determined. Twenty one human dental hard tissue specimens were immersed in 5 ml solution each for 336h. Every 48h weight loss was determined for each specimen and after 336h volume changes were calculated. Enamel microhardness was determined using a Microhardness Tester model HV-1000 and compared to normal enamel microhardness. Results: The pH values of beverages ranged from 2.37 to 3.1, showing no significant differences. All specimens presented color and surface texture modifications, weight loss and volume reduction. There were found significant differences between the mean values of weight loss and enamel microhardness of each type of specimens and type of beverages tested. The most representative findings were achieved by indentations done in specific zones on Sprite® immersed specimen. This result suggest that microhardness near the eroded surface was significant lower than in other zones. Conclusions: Data obtained have shown that all the soft drinks tested had an erosive effect, causing dental hard tissue dissolution. For prolonged time exposure titratable acidity may be a major predictor for erosive potential. Dental erosion may affect different levels of enamel causing decreased enamel microhardness.


2020 ◽  
Vol 15 (4) ◽  
pp. 5-10
Author(s):  
Bahlul Hamzaeb ◽  
Ayat Jafarova ◽  
Rena Huseynova ◽  
Rumia Abbasova ◽  
Shahla Yusubova ◽  
...  

Subject. This article analyzes existing theories about the prevalence and causes of dental caries, which is considered as a civilization disease. The crucial role of endogenous factors in the risk of caries, including a pulp and dental fluid, is noted. Data are given that acids do not actively participate in the process of demineralization, which is confirmed by numerous theoretical and hypothetical points. The role of some materials produced by dental industry based on this “pseudo-acidogenic” theory and used in the treatment of caries, as well as the false and negative consequences created by them in general, is analyzed, and adequate parallels are carried out. The purpose of the study was the theoretical justification of the key role of acetylcholine (the cholinomimetic mediator located on the Toms fibers) in the occurrence of dental caries. Methodology. Russian and foreign research works due to the etiology, prevalence and pathogenesis of dental caries were studied, and a comparative theoretical analysis of the available data on this issue was carried out. Results. Based on the results of numerous studies cited in the available literature and our studies, we performed an analysis of theoretical principles and substantiated the data that the process of demineralization occurring in dental caries cannot be caused by acids. Therefore, the only and decisive factor in the origin of the demineralization process is the occurrence of the process because of alkaline substances. Conclusions. Based on the studied references, we present the data that the most current theories of the etiopathogenesis of caries are imperfect in terms of solving the problem, which, in our opinion, requires further study of the process both of acetylcholine and the enzyme acetylcholinesterase inhibition in the local form and inside dental hard tissues.


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