This website uses cookies to ensure you have the best experience. Learn more

The Causes And Effects Of Microleakage In Posterior Composite Restorations; How Can Dentists Minimize These Phenomena

1584 words - 7 pages

Composite resins have been a significant aesthetic alternative to amalgam restorations for more than sixty years.1 A hindrance to this method of restoration is the phenomenon of microleakage. Microleakage results from an imperfect bond, leaving a microscopic gap, allowing molecules and ions to flow between the tooth and restoration interface.2 Lack of margin integrity has been implicated in patient sensitivity complaints, secondary caries formation, corrosion of dental materials, and aesthetically displeasing staining at the margin.2 This paper will discuss the basis and discovery of microleakage, causes and effects of the phenomenon including polymerization shrinkage, teeth whitening agents and certain etching techniques, as well as prevention methods the operator can employ to minimize microleakage in posterior composite restorations.
The study of microleakage dates back to 1912 when Dr. WE Harper first researched the phenomenon.3 Natural teeth were simulated in the study by using steel dies with class II preparations built into them. A tube was then attached through the pulpal floor of the dies and air pressure ranging from 3 to 30 psi was applied. The emergence of air bubbles from the margins indicated microleakage had taken place.
Polymerization shrinkage

A comparison of various composite resins
A research study comparing 17 different flowable and non-flowable composite resins was performed.4 The measured parameters include: shrinkage (vol%), contraction stress (Mpa), and tensile modulus (GPa). Figure 1 describes the materials tested. Shrinkage was measured by mercury dilatometry. Contraction stress measurements were obtained using a tensilometer apparatus as shown in Figure 2. Each composite resin was placed between the glass plate and the flat bolt head and pressure was applied. The composites were light-cured through the glass plate and the tensile modules was calculated 30 minutes after the curing process using the formula E = σ/ε, where σ is the stress (F/A) and ε, the strain (Δl/lο).
Light curing
Two composite resins, Z100 and Tetric Ceram were used to study how different light curing intensities affect margin adaptation.5 A small amount of each composite material was placed between two translucent strips and pressure was applied to give a thin strip of the composite materials. Four different methods of light curing were then applied to the composite resins: I. Standard mode, full intensity 750 mW/cm2 for 40 s; II. Two-step mode, 10 s at low intensity 200 mW/cm2 plus 30 s at full intensity 750 mW/cm2; III. Low intensity 200 mW/cm2 for 40 s; IV. Low intensity 200 mW/cm2 for 10 s. To measure polymerization shrinkage, the bonded-disk method developed by Watts and Cash was used.
Teeth whitening

Carbamide peroxide and resin coatings
To study the effectiveness of resin coatings as preventive treatment against microleakage caused by teeth whitening agents, forty caries-free extracted molars were used for...

Find Another Essay On The Causes and Effects of Microleakage in Posterior Composite Restorations; How Can Dentists Minimize these Phenomena

Research task into religion in Australia post 1945 - part one: Trends, Part two: Causes and Effects, Part Three: Ramifications, Part Four: What can churches do?

2140 words - 9 pages (e.g. marriage) through civil celebrants.Part Three: Ramifications for the future of Australian ChurchesThe impact of these trends causes and effects in Australia's current religious landscape include:Christian Denominations1. Increase in Orthodox religions: The increase in immigration from European orthodox countries (particularly Greece) will likely continue as immigration into Australia continues to grow .2. Continued decrease in Christian

Effects of Global Warming: What is global Warming? What causes it? What are the consequences? What can be done to prevent it?

1033 words - 4 pages matter release more than 10 times the CO2 released by human activities; but these releases have generally been in balance during the centuries leading up to the industrial revolution with carbon dioxide absorbed by terrestrial vegetation and the oceans.What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power

The Causes of Terrorism and How it can be Stopped

3107 words - 12 pages when we know how the mind of a terrorist works. Terrorists are like pests that one can not get rid of. Like a virus being exposed to anti-bodies, they just get stronger and "immune" to our defenses. "Terrorists are nothing if not adaptable. International terrorists have shifted tactics and targets many times over the years in response to changing circumstances. Shifting political fortunes and new antiterrorism measures will continue to force

Bulimia;topics;symptoms, causes, effects, treatments, what you can do to help get bulimia under control, risk factors, stress, and peer pressure, and who is most likely to develop bulimia

953 words - 4 pages individual wats a very large amount of food than most people would in a similar situation. Binge eating is not a response to intense hunger. It is usually a response to depression, stress, or self esteem issues.During the binge episode, the individual experiences a loss of control. The main topics dicussed are the symptoms, causes, effects, treatments, what you can do to help get bulimia under control, risk factors, stress, and peer pressure, and who

How can the ready availability of information via information technology change education and should and can these changes take place?

2196 words - 9 pages technologies, such as that of the ability to store, manipulate and retrieve data and information is an excellent example of the revolutionary effects administered by the information society.Technological determinism, an economic and social theory also in agreement with revolutionary change, suggests that technology is accountable for changing social and cultural practices (Snyder, 1997, p.132). The rapid decline in the industrial and manufacturing areas of

Contrast the symptoms of Alzheimer's disease with those of Parkinson's disease. What causes these different symptoms and how does this affect the treatment of these disorders?

3174 words - 13 pages (these are the most commonly used treatments). They are combinations of levodopa (a drug which breaks down in the body to form dopamine) plus a chemical which ensures the optimum dopamine concentration in the brain. They are effective at treating symptoms, although there are some side-effects. These include nausea, dizziness and constipation. Also, they can cause long term problems such as unwanted movements of the face and limbs (dyskinesia) and

Outline three different ways Christians can practice personal devotion in their tradition and analyze how these practices relate to the principal teachings and beliefs of Christianity

1252 words - 5 pages Catholics, it also states the teaching of the importance of Mary through the constant repetition of the "Hail Mary".Devotion can also be attributed to the use of icons, which are commonly used in the Greek-Orthodox Church. These icons are used to illustrate the life of Jesus and his mother, Mary, as well as stories from the scriptures which can physically and spiritually aid the worship of adherents.These icons are usually located in the Eastern

Causes and Effects of The Great Depression in America

3738 words - 15 pages apartments, even thoughthey failed to pay the rent or mortgage interest, others were evicted. To keep somesemblance of a home, families built shelters from discarded crates and boxes on vacantland or in the larger parks. Municipal authorities, unable to provide adequate help, wereforced to adopt a tolerant attitude against these squatters. As time passed the structuresbecame more elaborate and habitable, but older children were inclined to

Causes and Effects of Slavery in the U.S

1448 words - 6 pages slaves. The state of Massachusetts was shortly followed by Connecticut in 1650 and Virginia in 1661. However, these laws were not intended to protect the black slaves. They were intended to protect the rights of slave owners. By the time of the war of independence, the Africans had become slaves in the fullest sense according to law and custom. The law protected the plantation owner's rights over slaves, and thus the slaves were left with no rights

How Can We Remove The Causes Of Hunger In The World Today?

604 words - 2 pages How Can We Remove The Causes Of Hunger In The World Today?The world's population constantly increases, but the world's potential food production is more than capable of coping in the foreseeable future. The unhappy fact is that while western and westernized countries have plenty of food available and in great variety, many other communities, not all in the southern hemisphere, are perpetually at the near-starvation level.The causes are partly

How Can We Remove The Causes Of Hunger In The World Today?

593 words - 2 pages agro-chemicals are the best solutions; however, they need so much money. But, getting money to recover these solutions also depends on increasing the percentage of GNP that rich people donate to the poorer ones. Referring to the major political cause of hunger, supplying money or food medical supplies, air-dropping then to refuges, and sending money to the poorest countries from charitable appeals and affluent individuals are the most effective solutions to remove the causes of hunger in the world today. At present, all of the above solutions are really the best ones which are being applied from all over the world.***Thanh Nguyen's own knowledge***

Similar Essays

The Causes And Effects Of Micro Leakage In Posterior Composite Restorations; How Can Dentists Minimize These Phenomena

1242 words - 5 pages polishing can be completed in the same appointment as the restoration was placed, without negative effects on microleakage. Loading A study published in Dental Materials Journal, investigated the effect of loading on micro-leakage and microtensile bond strength of MOD composite restorations bonded with either self-etching or etch-and-rinse adhesive. The authors found that after loading, restorations bonded with a one-step self etching adhesive (G

The Causes And Effects Of Micro Leakage In Posterior Composite Restorations

1501 words - 7 pages BACKGROUND Composite restoration usage in dentistry is increasing. Because of this interest in the longevity and reliability of composite fillings also is increasing1. One problem that can occur with composite restorations is micro-leakage. This is when microgaps at the tooth-restoration interface allow fluids and bacteria into the restoration2. These gaps are formed when the material is polymerized and shrinks, which causes the material to

Why Is Monopoly 'harmful? How Can Regulation Ameliorate These Harmful Effects? What Problems Confront The Regulators?

828 words - 3 pages government weighs up the cost and benefits of ' monopoly' and concludes that they are in fact 'harmful', the government can adopt policies of intervention or regulation.The diagram below shows how a government can keep the price at a maximum Pm below market equilibrium.The government may feel that a price of op1 is excessive so a price of opm is implemented. At this price however, the monopolist is only willing to supply oq1 units while quantity

What Causes Parents To Physically Punish Their Children And What Effects Can It Have On The Child's Development?

1041 words - 4 pages The topic of family life has been an interesting topic for many researchers. They have been trying to figure out the details of family life and the effects it may have. The question is how corporal and physical punishments link to the internal and external influences that a child may be exposed to. Corporal and physical punishment can be defined as the striking of somebody's body as a form of punishment or discipline. Internal influences may be