Dental crowns, what makes it stay on?

Dental Porcelain Crowns

Dental crowns (ie. gold, porcelain fused to metal, and all porcelain) are used to reinforce a tooth's structural integrity and to allow normal functional occlusion.

But what makes the crown stay on the tooth?  A crown's retention is dependent on the following factors:

1) Taper.  The prepared tooth should ideally have 3 to 5 degrees of taper to allow for the restoration to be properly placed on the tooth. There should be no undercuts, as the restoration will not be able to be removed from the die and from the prepared tooth.  Conversely excess taper will limit the grip that the crown has on the prep, thus contributing to debonding of the restoration. Generally 6° of taper around the entire circumference of the prepared tooth, giving a combined taper of 12° at any given axial section through the prep is appropriate to both allow the crown for a proper fit and to allow enough retention.

2) Prep length.  The prepared tooth should also ideally have a minimum occlusal-gingival height of 4mm for molars and 3mm for anterior and premolars.  When such prep height is not possible, sometimes a core buildup is necessary to allow sufficient height and crown retention.


3) Adhesion.  There are two fundamental types of dental cements available, resin-based and acid-base cements.  Such cements allow the crown to adhere to the tooth by forming a chemical bond with the dentin and enamel.  The cement also forms an insulating and protective layer around the pulp.

If you have additional questions on the process of making sure a crown has sufficient retention, be sure to ask your family dentist.

From your family dentist in Bellevue,
Dr. Peter Chien
info@bellevuefamilydentistry.com
www.bellevuefamilydentistry.com

Floss, floss, floss :)

Dental Floss

It's mid November and patients are coming to the dental office to utilize their insurance benefits (a good thing!).  One trend I've been noticing is the hygienist talk to patients about flossing.  So I thought we can go through some benefits and pointers on why the dentist, hygienist, and American Dental Assocation favor the floss so much:

1) Dental floss is a composed of thin filaments; it can be made of plastic or silk, and is sometimes flavored.  Flossing removes food, bacteria, and plaque between the teeth.  It really is the best method to clean between the teeth, and around and underneath the gums.  Left alone, the bacteria can cause interproximal cavities (tooth decay).

The bacteria trapped between the teeth can then seep down into the gums, causing periodontal disease (gum and bone disease), gingival bleeding, and bone loss.

2) Flossing also helps clear out bad breath (halitosis).  The bacteria and food trapped between the teeth and left on the gums/gingiva can cause bacteria to grow within the warm and moist oral cavity, a favorable environment for bacteria.

3) Dental floss supplements tooth brushing.  Though tooth brushing is sufficient at removing bacteria and food debris/plaque, the toothbrush's bristles unfortunately cannot get between the teeth.  Some floss are waxed to facilitate movement between teeth.

4) Kids and adults of all ages should floss.  Ideally one should strive for daily flossing for optimal oral hygiene.  If not, a few times per week is better than no floss at all :)

If you have any questions regarding flossing, be sure to ask you family dentist and/or dental hygienist.  Remember to floss (and brush) lots!

From your family Bellevue dentist,
Dr. Peter Chien
(425) 614-1600
www.bellevuefamilydentistry.com

Busy lifestyle dental tips...

School is in full force and working parents are busy, constantly on the go.  It can be easy to forget about one's oral health.

Below are some ways to keep one's teeth healthy and in tip-top shape:

1) Brush twice a day with fluoridated toothpaste to strengthen your teeth's enamel.
2) Floss at least once a day to help remove bacteria and food trapped between the teeth (ie. the interproximal surfaces).  This will also help reduce your gums from bleeding, and help control gingivitis.
3) Eat healthy foods (ie. fresh meats, vegetables, milk) to promote good oral and systemic health.
4) Mouth wash to help rinse off excessive plaque and loosen food debris from the teeth
5) Drink milk fortified with Vitamin D, preferably 2-3 servings a day.  The calcium and vitamin D will not only strengthen your body's bones, but also the bones holding your teeth as calcium also plays a role in teeth retention.  For those lactose intolerant, look for milk products that are lactose free.
6) See your dentist regularly twice a year for checkups and cleanings.
7) Limit sugar frequency; it's okay to eat sugar, just make sure the sugar intake is in controlled quantities and that one brushes his/her teeth after sugar consumption to decrease caries/teeth cavities risk.
8) For those who travel, considering having a travel sized pouch with toothbrush, toothpaste, and floss.

From your family Bellevue dentist,
Dr. Peter Chien
(425) 614-1600
www.bellevuefamilydentistry.com

Happy October 31st! Healthy benefits of sweets, and teeth!

October 31st is finally here!  Many kids and families celebrate harvest on this day, and it usually involves lots of sweets and sugars!  Believe it or not, your family dentist may actually be in favor of kids and adults eating sweets.  Below are some guidelines to follow from a dental perspective:

• If possible, avoid hard whole sugar candies.  People usually like to leave these candies long term in the mouth, as the sugars from these candies can promote caries and cavities.  The bacteria in the oral cavity metabolize the sugars, resulting in a release of lactic acid that can cause dental decay.  A good alternative is to look for sugar free hard candies if possible.
• Chocolate is good for you! JAMA and ADA studies have shown that cocoa has excellent health benefits for the cardiovascular system, and for your teeth and oral health.  Chocolate, which is derived from cocoa beans, contain antioxidants polyphenols, flavonoids, and tannins.  Polyphenols actually inhibit bacteria effects, which can decrease bad breath and lower risk of tooth decay.  Flavonoids have been shown to decrease rate of tooth decay.  And tannins have been shown to prevent bacteria from adhering onto teeth.  Dark chocolate is best, and try to choose chocolate that is at least 70% cocoa for optimal health and dental benefits.  
• Chewing gum can help lower risk of cavities by promoting salivary flow.  With a healthy and excess flow of saliva, it helps "wash" teeth of plaque and sugars.   Watch out for gums that contain large amounts of sugars.  Sugarless gum is a good alternative to consider.

October 31st is a great time for adults and kids alike. Be safe everyone, and feel free to ask your family dentist if you have any questions on sugars and oral health.

From your local family Bellevue dentist,
Dr. Peter Chien
www.bellevuefamilydentistry.com
(425) 614-1600

Natural Looking Porcelain Crowns

Have you ever thought what makes porcelain dental crowns so natural looking and strong?

One type of porcelain crown is made from lithium disilicate, a ceramic restorative material that garners excellent esthetics.  With a flexural strength of 360-400 MPa, it has excellent strength and is suitable for anterior crowns where esthetics is desired, as the outside layer is veneered (or layered) to achieve optimal shade, value, chroma, and brightness.  One example is IPS e.max, where the crowns can be pressed or milled from an intra-oral digital scanning device, and then milled (fabricated) from an in-house lab milling machine.

For posterior teeth, a single layer monolithic lithium disilicate may be optimal as this uniform layer gives porcelain crowns outstanding strength.  Its flexural strength is near 1,000 MPa, and its compressive strength makes it as strong as gold and natural teeth.  This makes allows these crowns to be highly resistant to chipping and fracture, and its strength makes it a solid choice for even those who have bruxism (night time grinding) and severe Temporomandibular Disorders (TMD) and TMJ issues.

If you have any questions regarding porcelain crowns, consult with your family dentist to see if they are suitable.

From your family Bellevue dentist,
Dr. Peter Chien
(425) 614-1600
www.bellevuefamilydentistry.com

Dental Sealants for Kids!

Now that school is up and running again, parents may have heard their children's school nurse mention dental sealants.  So what are they?  Sealants are a protective plastic coating dentists place on posterior teeth (back teeth).  Posterior dentition, especially molars and premolars, have deep occlusal grooves, pits, and fissures.  These deep grooves are usually very fine and thin, they can be difficult to maintain proper oral hygiene.  The toothbrush's thickness is usually greater than that of the teeth's grooves, so bacteria and plaque have a high tendency to remain trapped inside the tooth.  The result is an increased likelihood of developing tooth decay.

Your dentist will first make sure the tooth's grooves are clean with a high powered flush and cleansing material.  After the tooth is properly cleaned of debris, the tooth properly dried and isolated, the sealant is flowed onto the tooth.  The sealant is then light cured and hardened, thereby protecting the grooves from potential decay (cavities).

Sealants can be a viable preventive treatment for kids and adults alike.  Dental sealants are not permanent and can wear away (ie. fall off) over time, but it's a great cost effective and simple method to help ward of cavities.

Your family dentist should be able to help you decide if dental sealants are suitable for you and your children's needs.

From your family Bellevue dentist,

Dr. Peter Chien
(425) 614-1600
info@bellevuefamilydentistry.com

Single Tooth Whitening

 

TOOTH WHITENING

Do you have a single "dark colored" tooth?  Have you ever thought about getting it whiter so it blends in with the adjacent teeth?

Sometimes a single tooth can be discolored if it previously had root canal treatment.  If so, one option is to have that single tooth internally bleached.  How does it work?  Also called "walking bleach technique" your dentist may place either a high concentration of 35% hydrogen peroxide, carbamide perioxide, or sodium perborate.  The solution is left internally within the tooth for a few days, and the tooth is then re-evaluated for shade.  This internal bleaching is then repeated again if necessary.

This single tooth non-vital tooth whitening method is fairly noninvasive, and can be a conservative option compared to a veneer or crown.  Talk to your dentist to see if this "walking bleach technique" is right for you.

From your family Bellevue dentist,
Dr. Peter Chien
www.bellevuefamilydentistry.com
(425) 614-1600