Category Archives: Dental Blog

In the month of October 2011, a colleague and I visited the American Dental Association Convention in Las Vegas at Mandalay Bay. It never ceases to amaze me as to how may dentists and auxiliary staff attend these annual sessions. Every year the ADA rotates the site for this convention – and this year it happens to land in Las Vegas. The typical set up of these large annual meetings are the first floor containing exhibits on new dental technology and materials and on the floors above, classes are held for dental related continuing education. This year there must have been over forty thousand attendees … perhaps many of them here because they wanted to gamble afterwards?

In total I spent 2 days at this convention – which I felt was not enough. Visiting the many booths help me upgrade all my necessary dental materials such as my dental composite materials and prepared me with a list of many other dental upgrades to come in our new office that was currently under construction. The classes I took up on the 2^nd and 3^rd floor, as always, were helpful in broadening and improving my knowledge on my dental surgery skills and education.

Posted by Dr. Brien Hsu at 9:13 PM

A patient came in about a month or so ago, having sensitivity to cold on several upper and lower teeth.  The symptoms started roughly about one year ago. One dentist had recommended doing fillings on several teeth, while another even recommended a root canal and replacing several fillings. Looking for a third and final opinion the patient sought out my services. After x-rays and several tests, I determined that no fillings or root canals were necessary. I advised the patient to stop using any form of whitening toothpaste and prescribed a medicated paste to apply daily for a few weeks. On their follow-up appointment, the patient no longer had any more symptoms of sensitivity. They were thankful that I had saved them a lot of money by not doing any fillings. My response was, “Money you can always replace, but tooth structure cannot be replaced once they have been drilled on. While I’m happy you saved some money, I feel even better that you were able to save your tooth structure.”

So how was I able to determine that there was no need for fillings or even a root canal? The tests and x-rays did not show decay or faulty fillings and after conversing with the patient, I discovered that they had been using a new whitening toothpaste for about one and a half years. I could not be certain that this was the main cause of the patient’s problems, but from my past experience with many other patients having similar symptoms, I decided to proceed with stopping the usage of all whitening products and to prescribe the medicated paste. And just like many of my other patients the problem was solved.

I find that, with the on-going trend of desiring whiter teeth, a craze for whitening products is developing – everything from over the counter take home kits to special whitening toothpastes. Many patients have been experiencing sensitivity to cold after using these products. Most of these patients have less dense or thinner enamel and the chemicals that manufacturers use to whiten teeth are in essence damaging the tooth structure. These same chemicals have been modified by various companies and are now being used in all whitening toothpastes. Luckily if caught in time, these symptoms are reversible by following some simple protocols. It makes me wonder sometimes, what will happen in the future as more and more of these cases become more prevalent? Slowly I am seeing the number of whitening toothpastes increase in the market, while the number of regular toothpastes diminish.

On August 14^th, 2011, I spent my Sunday morning and afternoon donating my dental services at an outreach clinic for underprivileged families in San Bernardino. In total I saw 18 patients. As a dentist, I always try and salvage a patient’s teeth. So it pains me to see that the majority of my patients seen on that day, needed extractions. Some of these teeth were so badly damaged and infested with infection that there was no chance of saving them. There was one patient in particular that I remember. She had an upper left wisdom tooth that was fractured and abscessed. The tooth was diagnosed for a surgical extraction -preferable by an oral surgeon specialist. None of the other doctors at the free clinic felt they had the experience or the tools to perform the surgery. I could see that the patient was in terrible pain and was afraid she would not be seen. I did not want to see the patient go home in discomfort, so I stepped in to perform the surgery. The majority of the patients who need surgical wisdom teeth extractions in my practice are referred to our oral surgeon in order to facilitate treatment. However because of my extensive past experience in oral surgery, I was still able to extract the tooth in less than 20 minutes, even though the free clinic was not properly equipped to manage these types of surgeries.

I wonder sometimes, what would happen to these patients were I not present at these clinics. It seems that at every free clinic that I volunteer for, not only am I always the youngest doctor there, but I’m always taking on the more complicated cases and taking care of the most number of patients. However, I am still very thankful that there are other doctors who volunteer their time. Without the extra help, it would not be possible for these free clinics to exist. I regret that I have not been able to donate my services as often this past year. My baby girl, Hanna was born with a severe heart defect last year and twice she would not have made it, if it were not for the modern day advances in infant heart surgery. Needless to say, I have spent many days and nights at the hospital and at home cherishing every moment I have with her. However, I feel that my sick daughter is still not an excuse for not focusing some of my time towards charity.

In summary, the condition of the mouths that I saw that day at the San Bernardino Outreach Clinic were a lot worse than the previous times that I have volunteered. In addition it was odd that the number of adult patients far exceeded the number of children patients. And this is comparing patients seen over the 12 years that I have volunteered my dental services. I suspect, that the deteriorating economy played a large factor in this phenomenon. Regardless, it always warms my heart, when I can see the thanks in the smiles and eyes of the many patients that I helped that day. Giving back to the community always feels right especially during these times of economic instability. It is also during these times that I truly feel fortunate to have a thriving practice with patients who take pride in maintaining their oral health.

On a weekly basis, I seem to always have at least one conversation with one of my patients in regards to white fillings. Just recently in July, I had someone ask me why their old white fillings done by their prior dentist were failing. Meanwhile some of their old silver fillings that were done during their childhood were still going strong. In order to address the questions that many people may have in regards to white fillings, I have decided to compose a brief explanation:

White fillings in general have a life expectancy of 2 to 25 years, while silver fillings will usually last anywhere from 15 to 30 years. The reason there is such a wide discrepancy between white fillings is because these fillings are very technique sensitive. In addition there are also many types of white filling materials and bonding agents that may be used by the dentist. Silver fillings on the other hand, are far less technique sensitive and there is basically only one type of silver filling material.

When determining the life expectancy of white fillings, the hand skill and technique level of a dentist are typically an unknown and always a changing variable. The patient has no real control over the proficiency of the dentist at the time of service. However the type of white filling and bonding agent is a constant and more controllable variable because of the vigorous lab and in-vitro testing done in order to get these dental materials on the market.

The longevity and strength of a white filling material is determined by numerous factors. However in order to simplify, I have listed two very important attributes: Polymerization shrinkage and Compressive Strength. Please keep in mind that each white filling material will measure up differently for each category. Better numbers in shrinkage rate will not always result in better numbers in compressive strength and vice versa. It is up to the dentist to determine the best material with the attributes that will provide the best results for each individual case.

The polymerization shrinkage rate is measured by a percentage. The lower the shrinkage rate, the lower the chance of a cavity developing under the white filling. Basically a lower shrinkage rate translates into a longer lasting white filling. The shrinkage percentage can range from as low as 1.4 percent to as high as 5 percent. Again the lower the percentage the better the material.

The compressive strength measures the ability of the white filling to withstand the forces of mastication and grinding. The higher the compressive strength, the less likely the white filling will be crushed when chewing and grinding with the teeth. This attribute is measured in MPa and can range from 100 to 500 MPa. The higher the number, the better the material.

Now the type of bonding agent will determine how well the white filling bonds to a tooth. The stronger the bond, the longer the white filling will last. This bond strength is also measured in MPa. The bonding strength to enamel can range from 10 to 38 MPa. While the bonding strength to dentin (the inside portion of a tooth) can range from 5 to 44 Mpa. Again the higher the MPa, the better the bonding agent. However, just because a bonding agent has a stronger enamel bond, may not mean it will have a strong dentin bond and vice versa – it is up to the dentist to determine which agent will work best in each case.

There are over a hundred different kinds of composite material and over fifty different kinds of bonding agents. Typically the better the material, the higher the cost. In addition every few years new materials and bonding agents are introduced – so a dentist must keep up to date, if they wish to provide the best level of care.

That being said, I typically will explain to patients that we use the best bonding agents and white filling materials on the market and we will constantly change these out for better products regardless of the cost on a regular basis. We also use a variety of different bonding agents and filling materials depending on the type of cavity or tooth we are working with. We always try and choose the best material for each case. I spend hundreds of hours every year doing research on all our dental materials. Most dentists have no clue as to how their material rates up against others. There are some dentists who will only use the dental material that gets them the best bang for their buck or the material that they had used long ago in dental school – this in essence will lead to more failed white fillings.

As of today, the white filling material that we use at our dental office has a polymerization shrinkage rate of 1.48 % and a compressive strength of 500 MPa. Our bonding agent has an enamel bonding strength of 35 MPa and a dentin bonding strength of 44 MPa.

In early June, my staff and I attended a continuing education course on treating children who have extreme fears of dentistry. It was titled “Little People, Big Problems.” Because I see a lot of children in my practice, I thought this course would be excellent for learning new tips. Sitting in that course brought back some memories from the past. As part of the staff at the USC dental mobile clinic in 1999, I did charity work for under-privileged children all over California. I remember we would have to sterilize and set up treatment rooms in make-shift clinics – most of which were cafeterias or auditoriums and elementary schools. We would then  have to  treat over 500 kids in one day. At the end of those busy days, I always felt exhausted both mentally and physically, but just seeing those happy innocent smiles on so many children made it all worth it.

At the end of the course, my staff had commented that they felt as if they learned “nothing.” I explained to them that because of my extensive experience with sedation and working with children, I had trained them on many techniques for working with kids. Apparently, the course was geared towards those dentists who were having “Big Problems” with children – which did not apply to my staff and I. Even though we may not have learned anything new, I still feel that it is important for my staff and I to attend these types of courses. Without sitting through these lectures, there is no real way of knowing if new information would have helped our practice. As dental professionals, in order to provide the best level of patient care, I feel we must continuously make every attempt to learn and improve ourselves in all aspects of dentistry.