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