White Fillings versus Dental Amalgam Fillings

I have been staring at old dental amalgams for nearly 30 years wondering why the teeth containing them fracture or break up & why there is almost always dental decay beneath them when I go to fix them.

Silver Fillings vs White Fillings
At Milford Dentists, North Shore, I haven’t placed a Dental amalgam (silver/metal) filling since 1999. I have placed white fillings aka composite resin fillings successfully instead – this is because white filling bio-mimics tooth structure i.e. it behaves very similarly to the tooth that has decayed or snapped off that it is replacing 

But what is going on here? Why have I opted for Milford Dentists to be Mercury Amalgam Free since 1999?

Over the last couple of years clever researchers, some of whom are dentists have worked out why dental amalgam fillings end up making teeth snap, fracture & decay; eventually making the tooth fail. This has reinforced my own theories that Mercury Dental amalgam fillings are a disaster for teeth & conversely white composite resin fillings are a much better more biomimetic (life like) alternative.

There are a few physical processes going on when you have a dental amalgam filling sitting in your tooth.

1. Temperature changes making the filling expand & contract
2. The tooth cusps & dental amalgam filling all moving in different directions during chewing 
3. The actual dental amalgam cavity preparation destroying parts of the tooth that actually hold the tooth together

Temperature Change in Mercury

Around 50% of dental amalgam is made up of mercury. Mercury has been used in thermometers for years because it expands and contracts a great deal with temperature change. So when you, say, have a hot drink, the mercury in your dental filling heats up & expands making the filling bigger. This puts a whole lot of pressure on your tooth & eventually your tooth can’t take the strain & cracks/fractures/snaps.

Conversely when you have something cold to eat or drink – say ice cream, your filling contracts leaving a gap around it. Conversely, white bonded composite resin fillings have a similar co-efficiency of expansion as the tooth with temperature change i.e. composite resin expands & contracts just like your tooth with temperature variations. White fillings are also bonded or “glued” into the tooth cavity which means there are no gaps around the edges.

Everything is moving when you chew

When you chew you are putting a lot of pressure on your teeth (approximately 150-newton centimeters of torque). Surprisingly, for something so solid, a tooth will twist and bend a little under this pressure. In tests on teeth (in vitro), a tooth with a medium sized amalgam filling will flex 26 times more than a tooth with a similar sized bonded white filling.

In fact, the tooth with a bonded white filling will flex almost the same amount as a healthy tooth. This is because the white filling not only fills the cavity, it also bonds the tooth back together again biomimetically, so the tooth & white filling are swaying & twisting as one.

Essentially the teeth tested with the amalgam fillings are twisting & bending in all different directions i.e. the cusps are moving away from each other & the amalgam filling is jiggling around in the cavity, as the mercury amalgam is just a hole filler & does not “glue” anything to anything.

The actual dental amalgam cavity preparation

Because mercury dental amalgam is a hole filler it needs to be “keyed” or locked into the tooth by undercuts so that it doesn’t fall out. At dental school, this type of dental cavity preparation is called a “G V Blacks” cavity. The cavity shape destroys “girders” of enamel that hold the tooth together.

In the last 10 years, dentists have discovered that the tooth is a lot more complicated structurally than we had thought. There is a complex framework of stronger enamel spokes that connect together within a strong enamel rim running around the tooth on the biting surface. If the spokes and or the rim is cut during a dental amalgam cavity preparation the tooth is weakened, eventually leading to the tooth snapping.

Imagine trying to ride a bike with some of the spokes broken or part of the wheel rim missing.

As already mentioned a bonded composite resin filling glues the tooth back together & because white fillings are bonded they do not need to be “keyed” into the tooth. This means cavities for white fillings are smaller than corresponding cavity shapes for an amalgam filling. 

Read about safe dental amalgam filling removal here

A lot of the time teeth can be repaired using white composite resin filling material. As well as strengthening the tooth with the bond or "glue" holding each part of the tooth to the rest of the tooth these restorations look very natural -

If the tooth is weakened by tooth cracks or decay sometimes the optimal option to strengthen & hold the tooth together for the longer term & at the same time improving its appearance is a dental porcelain crown or overlay. This acts like a crash helmet for the tooth holding everything together.

Posted by Andrea Clarke BDS

Milford Dentists is proud to help the good people of the North Shore with all their dental requirements - From Devonport and Belmont up through Takapuna, Castor Bay, Mairangi Bay & Browns Bay as well as Albany, Northcote, Hillcrest & the Whangaporoa Peninsula.

The Tooth Decay Process: How To Reverse It And Avoid Cavities

No-one likes it, but we’re all used to it. Tooth decay and cavities can be avoided, yet most of us have experienced many painful trips to the dentist. Root fillings, tooth crowns, composite veneers – they’re no fun for anyone! If you want to keep your smile looking great for years to come, take care of your teeth before any problems arise. Here are five ways to reverse the tooth decay process.

Brush Twice Daily

Some of us are better at it than others, but we should all be brushing our teeth at least twice a day with good technique for 2 minutes. You know when you’ve crashed somewhere after a party, and your mouth is yuck and you scrape fuzzy stuff off your teeth? That’s plaque.

Plaque is the soft, sticky, bacteria-laden film that builds up on your exposed enamel. When left alone for too long, plaque can harden into tartar, which in turn can lead to gingivitis, an early stage of gum disease. Plaque can also cause tooth decay and – just as terrifying – bad breath.

Brushing your teeth regularly will remove plaque, leaving your mouth healthy and smelling fresh. Use a soft bristled toothbrush and brush in a gentle, circular motion. 

Floss Daily

Floss is an interdental cleaner, designed to clean the tight, hard to reach spaces in between your teeth. It may seem pedantic, but it’s really not. Brushing removes plaque from most of the surfaces of your teeth, but flossing removes plaque and food particles that are lodged in the parts the tooth brush doesn't reach.

Floss at least once a day.

 

Eat a Balanced Diet

A no brainer, right? What you eat affects your oral health. We all know that sugar causes tooth decay, but which foods are good for our teeth? Whole grains, fruits at main meal times, vegetables, lean sources of protein such as lean beef and legumes, and low fat and fat-free dairy foods are your friends.

But it’s not just what you eat – it’s how you eat it. Foods that are eaten as part of a meal do less harm to your teeth, as more saliva is produced during longer eating sessions. Saliva helps wash down food and lessens the effect of acids in food. If it’s not realistic for you to quit snacking, reach for something crunchy and fresh, like a stalk of celery!

Drink Plenty of Water

Did you know that saliva is 99% water? Having low levels of saliva causes a dry mouth, which leads to bad breath and all sorts of dental issues. As mentioned above, saliva washes down food and protects your teeth during meals. In fact, saliva is your mouth’s first defense against mouth decay.

Visit Your Dentist Twice a Year (Or More)

We recommend you visit a dentist twice a year for a regular check-up. If you are a smoker, pregnant or currently have a gum disease or are prone to mouth infections, you should make an appointment with your local dentist every 3-4 months. It’s cheaper to prevent tooth decay and cavities than it is to fix them, so be proactive and look out for your oral health!

Why Have I Got Toothache?

Toothache can range from a tooth being sensitive to cold, to pain on biting or even be a constant pain that mean people can't sleep properly! There are many causes of toothache and we will discuss some of these and different options available for how they can be treated. 

Dentine Hypersensitivity

This tends to occur in patients who's gums have shrunk back due to gum recession, leaving the roots of their teeth exposed. The roots of a tooth can become incredibly sensitive to cold, touch or even tooth brushing because they aren't protected by enamel which is the hard outer layer we have on the tops of the teeth. In these early stages we can take a non invasive approach, where a fluoride gel is placed on the exposed root surfaces and starting to use a sensitive toothpaste that you place on the exposed root surfaces before going to sleep and leaving on overnight to soak into the tooth.

Over time these root surfaces can become worn incredibly quickly as they are softer than enamel. As the wear progresses deeper the nerves in the tooth can become very inflamed and painful, to the point where toothache becomes more constant and worsened by heat in which case teeth may require root canal treatments or even extracting! So one option available would be to cover exposed root surfaces with a composite filling, which helps to protect the nerves in the tooth and treat the sensitivity to cold.

Reversible Pulpitis

This most typically occurs as a result of decay deep in a tooth, in close proximity to the nerves. This causes the nerves in the tooth to become painful in short bursts usually when something cold comes into contact with the tooth. At this stage treatment is based around removing the cause which is the decay deep in the tooth and placing a filling. However in the future the nerves in the tooth may die off as a result of the previous damage they have received in which case root canal treatment or extraction may be considered.

If left untreated reversible pulpitis will progress to irreversible pulpitis or to the point where the tooth becomes infected.

Irreversible Pulpitis

This again is most commonly caused by decay deep in the tooth but at this stage the nerves in the tooth have become so badly damaged that they are going through the process of dying. The nerves in the tooth can be constantly painful throughout the day even without any trigger which can worsen when heat is applied. At this stage treating the cause of the problem means removing the nerves in the tooth either by way of a root canal treatment or removing the tooth itself.

If left untreated the tooth will eventually become infected leading to further pain and possibly a facial swelling in the future.

Infected Tooth

At this point the tooth will usually be constantly painful through day and night, causing sleepless nights, which can be worsened when pressure is applied to the tooth when biting and chewing. Tooth infections can be present without experiencing any pain however if left patients risk bacteria entering their blood stream or facial swellings that interfere with breathing. The treatment options here involve removing the cause of the infection which is bacteria within the root canal system of the tooth through root canal treatment or removing the tooth.

Now it would be great if we can avoid these problems before they occur which is why we advise people to regular dental check ups and consider having fillings on decayed teeth before they get to this point.

Common Signs You Need Fillings

Taking care of your dental hygiene is a big part of your overall health. Besides a regular brushing and flossing routine, it is important to watch out for signs and symptoms that may suggest the need for dental fillings. Undiagnosed dental problems can become a huge problem later in your life, and can keep adding to dental decay for years. In this post, we discuss some of the common signs and symptoms that indicate you may need a filling for your tooth. 

What is a Dental Filling?

Tooth fillings are materials that bond to your teeth, are made from non toxic substances that are put onto your teeth to restore a hole in your tooth, or to repair a chipped tooth and return it to its original shape. there are usually three types of fillings that dentists work with; they are composite and GIC (Glass ionomer cement) and are white in colour, and a third type is called amalgam which is a silver coloured filling material. Fillings can last a long time, if the need for them is detected early and they are taken care of after the procedure. Smaller fillings tend to generally last more time, while bigger fillings may need more precision to place. 

When do You Need a Filling?

There can be several reasons why you may need a tooth filling. Some of the common signs are experiencing sensitivity while drinking or eating very hot or cold liquids and foods, such as iced drinks or icecream. You may also have a toothache that gets worse with time, and makes it difficult to bite or chew. The pain sometimes extends to your gums, and swelling may accompany it. The dentist will often ask you about the intensity of the pain, and the frequency as well. Sometimes, painkillers help to temporarily relieve the pain. Tooth decay can affect your teeth severely, if it is not addressed in time. Tooth decay affects the layers of your teeth and is caused by acids in the plaque biofilm sitting on your teeth. Dental decay if in small amounts is in most cases always treated with a filling to avoid further progression of the cavity. Serious decay however requires more complex treatments - if the nerve is involved a root canal treatment or extraction is required.  Bigger carious lesions can be restored with either a bigger filling, overlay or crown. 

Other Reasons Why You May Need a Filling

Apart from the most common reasons such as toothache from tooth decay, or sensitivity while biting or chewing that require you to consult a dentist and perhaps having a filling, there may be other factors such as a hole or a gap in your teeth that seems to increase with time, dark spots that you may notice, food impaction (food getting stuck between your teeth), rough or fractured teeth and floss that keeps tearing everytime you use it in a particular spot. You may also need to redo a lost or broken filling so consult your dentist for the same.

Make sure you are aware of these signs and symptoms that may require a filling and work your way to a beautiful smile! 

What Would Happen if You Never Treated a Cavity?

Dental cavities can be a hassle for busy people who are short of time. Although ignoring the pain and discomfort of tooth cavities isn’t advisable. The outcome for ignoring a decaying tooth or cavity can only be further deterioration. Here is a guide to learning what happens when you leave a cavity untreated.

Further deterioration and decay

Ignoring a cavity means that it will inevitably grow in size. Additionally, dental decay will make tooth structure brittle and prone to cracking and the bacterial infection (tooth decay) is likely to compromise surrounding teeth as well.  At an early stage dental decay would would most likely result in a tooth filling, which is generally successful and straightforward.  

Severe nerve pain

A consequence of dental decay can be pain which can’t be conveniently ignored as a cavity progresses. The decay eventually reaches the nerve. At this stage, routine dental fillings won’t be enough to solve the problem. A solution would be either a root canal treatment or tooth extraction.

Bacterial infection

A bacterial infection may arise in the  jaw bone when bacteria destroy the pulp/nerve in the middle of the tooth.  This could lead to a change in the pain symptoms and sometimes swelling of the gum around the area. Also bacterial infection in the gum and bone can lead to systemic infections (ie infections and inflammatory damage elsewhere in the body like cardiovascular disease)

Serious illness and death

In the days before modern technology in western countries, serious illness and death as a result of a tooth cavity were more commonplace. Nowadays it’s rarer, but it’s still technically possible. Although this article isn’t an attempt to scare-monger it does aim to help people to consider real risks. The rule of thumb is that tooth cavities evolve and worsen quickly. The results to your health, well being and wallet can be disastrous.

Staying on top of your dental hygiene

The good news is that to mitigate against the damage caused by cavities, you can make some regular routinized changes to your life. When practiced daily, these changes will keep cavities at bay.

• Brush twice daily with a fluoride toothpaste.
• Clean in between your teeth daily with dental floss
• Eat nutritious, balanced meals and avoid sugary snacks between meals.
• Visit your dentist regularly for a general check-up. A regular oral examination will rule out the vast majority of problems. 

Having regular check-ups for cavities ensures that these horrible outcomes remain worst-case scenarios that only happen to other people. Speak with Milford Dentists about a broad variety of services we offer, including cosmetic dentistry, tooth whitening services, fillings, dental implants, orthodontics and braces. Our dental services cover the full spectrum of life-long care and our patients and their families are happy with our services.