The golden rule is an ancient principle used in mathematics, art and architecture to provide a guide for esthetic pleasing proportion. A line is divided into two parts such that one part is the mean and the other part is the extreme. The ratio of proportion is 1 to 1.61'8, mean to extreme. Interestingly, the same progression of numbers can be achieved by multiplying by 1.618 or dividing by 0.618. The principle of golden proportion to evaluate facial and smile esthetics was described in the following article. Levin El. Dental Esthetics and the Golden Proportion J Prosthetic Dentistry 40:244-252 1978 Several books and articles describe the following proportions as golden proportion mean to extreme. It should be noted that these measurements are taken face on only as if done on a photograph and not three dimensionally as would be done on the face. PROPORTIONS MEAN TO EXTREME

A crown is a special method used to restore weak teeth. The crown surrounds and supports tooth structure which is not strong enough to support itself. The tooth is reduced and shaped around the outside and across the top so a crown can fit tightly over it. Crowns are sometimes referred to as "caps" and the terms are interchangeable.

Porcelain veneers are thin chips of porcelain constructed to fit over your teeth. They can change tooth color, position or shape. Modern bonding procedures and new porcelains create exceptional strength and appearance. Most often teeth need to be reduced so the final appearance is not thick and novocaine may be required. I personally have cases over twenty years old and can tell you the results are beautiful and last a long time ..... if they are done properly. http://www.wellesleydentist.com/porcelain%20veneers.htm

All-porcelain (ceramic) materials include porcelain, ceramic or glasslike fillings and crowns. They are used in inlays, onlays, crowns and cosmetic veneers. Porcelain fused to metal is another application for this material and has similar properties as described below with the notable exceptions of increased durability due to the metal substructure, the necessity for more tooth removal for that substructure and, in rare cases, a localized allergic reaction may occur. New porcelains fired to very high temperatures are as strong as metal. Procedure: Porcelain restorations and crowns are made to order in a laboratory and then cemented into place. Porcelain is well tolerated by gum tissues, and last longer than composite. A dentist will remove old filling materials and diseased tooth structure. A substructure often referred to as a base or core build up is placed for thermal insulation and improved retention. The tooth is shaped so the porcelain can be slid into place. A temporary filling is made of a plastic or acrylic material. It is placed with weak cement so it can be removed later. You should not chew on a temporary filling as it might be dislodged. Porcelain can be bonded to tooth structure so less tooth structure is removed when all porcelain crowns are done. Cost: Porcelain restorations require two appointments which combined with the cost of the gold and laboratory fees makes these restorations much more expensive. They are much more expensive than amalgam or composite but similar in cost to gold restorations. Durability: Porcelain restorations are very durable. Porcelain can fracture but it takes high intensity force to fracture. Appearance: Porcelain restorations replicate the appearance of tooth structure almost exactly. All porcelain restorations produce high translucency similar to tooth structure. There is never a black line around the margins as happens with porcelain crowns with metal substructure. Metal can show or light is not transmitted through a tooth to produce an unsightly black line. Safety concerns: There are very few safety concerns with porcelain restorations. Advantages: • Tooth-colored with excellent translucency. The color looks similar to natural tooth enamel • Very little tooth is removed when used as a veneer, more tooth is removed for a crown • Good resistance to further decay if it fits well • Is resistant to surface wear but can cause some wear on opposing teeth • Resists leakage because of precise shaping and fitting • Does not cause allergic reaction Disadvantages: • Material is brittle and prone to cracking under biting force • May not be recommended for molars • Generally, requires a minimum of two appointments to complete • High cost, similar to gold

Amalgam Amalgam is an alloy (mixture) of silver, copper, tin, zinc and mercury. Mixing these elements results in a soft material which is easily worked. Initial hardness occurs within minutes but full hardness requires hours. For that reason, a patient cannot chew on an amalgam filling right away. Strong compressive strength makes it an ideal restorative material but low shear and tensile strength mean it must be surrounded by strong tooth structure. This material is easy to use and relatively inexpensive. There is controversy surrounding health consequences of filling materials that contain mercury. It is considered a safe restoration in the United States but has been virtually banned in many foreign countries. The material should not be used in areas where the remaining tooth structure is weak. It cannot be used on teeth where aesthetics is a concern due to the color. The material will deteriorate with age which may require replacement. Amalgam may lead to cusp fracture which results from wedging effects from mechanic forces and expansion with heat. Procedure: Amalgam restorations are completed in one appointment, however, a final finish is often completed at a later time. Teeth require preparation to remove diseased tooth structure and provide support for amalgam. In dentistry, this is referred to as retention and resistance form. More healthy tooth structure is removed during amalgam tooth preparation than composite tooth preparation. A matrix is placed to contain the amalgam in the tooth during placement. Components are mixed with a tritrator, amalgam condensed and the restoration hand carved to replicate original tooth shape. Cost: Dental amalgam is the most cost effective dental filling material. It requires less time to place than composite and other materials. Amalgam requires less skill than composite and other materials and is placed in one appointment. Durability: Dental amalgam has a long term track record of success. It requires sufficient remaining tooth structure to support it; however, it is successful in larger restorations if forces are of average strength. Remaining tooth structure is not supported by amalgam and is more prone toward fracture resulting from more extensive tooth preparation and amalgam contraction expansion. Appearance: Amalgam is silver in color and deteriorates with time to look rusted on the surface. Leakage eventually makes teeth look gray. Safety concerns: Dental amalgams contain about 50% mercury, which may have neurotoxic effects on the nervous systems especially of developing children and fetuses. When amalgam fillings are placed in teeth or removed from teeth, they release mercury vapor. Mercury vapor is also released during chewing. The amounts released are considered to be safe by the FDA and the American Dental Association. Advantages: -Good to excellent durability: Stands up to biting forces -Strength proven over a long history of use -Can be placed in one visit -Self sealing to resist leakage: Resists further decay -They last longer than other direct types of fillings -Below average relative cost: Least expensive material -Well tolerated by the patient -Excellent when placed in difficult wet conditions Disadvantages: -Silver color gives it a poor appearance -Corrosion darkens the tooth with time -Amalgam corrosion results in leakage and failure with time -Possible allergic reactions to metals -Possible short-term sensitivity to hot or cold after the filling is placed -To prepare the tooth, the dentist may need to remove more tooth structure to accommodate an amalgam filling than for other types of fillings -Placement requires removal of healthy tooth structure -Amalgam scrap contains mercury and requires special handling to protect the environment -Hard to identify cavities early _In large restorations, the remaining tooth structure weakens and fractures

Gold has modifiers added to it which increase hardness. Harder gold may be required in a filling designed to support weak tooth structure. Softer gold can be used in small restorations where the tooth can support itself. Most gold restorations are cast in a laboratory which increases the work, time and cost. Strong compressive, shear and tensile strength make it the ideal restoration for any operative treatment. Gold can be used in any situation because of its strength, wear, non reaction to surrounding tissue and longevity. It is not commonly used because of the color, time for construction and cost. Gold requires two appointments, laboratory time and the cost of constructing a temporary restoration for use while the laboratory makes the gold restoration. Gold covers tooth structure to prevent fracture, however, esthetics often limits its use. Gold alloys contain gold, copper and other metals that result in a strong, effective filling, crown or bridge. They are primarily used for inlays, onlays, crowns and fixed bridges. There are two categories of gold fillings, cast gold fillings made with 14 or 18 karat gold, and gold foil made with pure 24 karat gold that is burnished layer by layer. Procedure: Gold fillings are made to order in a laboratory and then cemented into place. Gold inlays are well tolerated by gum tissues, and may last more than 20 years. A dentist will remove old filling materials and diseased tooth structure. A substructure often referred to as a base or core build up is placed for thermal insulation and improved retention. The tooth is shaped so the gold filling can be slid into place. A temporary filling is made of a plastic or acrylic material. It is placed with weak cement so it can be removed later. You should not chew on a temporary filling as it might be dislodged. Cost: Gold restorations require two appointments, the cost of the gold and laboratory work and fees. They are much more expensive than amalgam or composite. Durability: Gold fillings have excellent durability, wear well, and do not cause excessive wear to the opposing teeth. Unfortunately, they do conduct heat and cold, which can be irritating. Gold fillings are usually quite expensive, although they do last a very long time. It is not uncommon for a gold crown to last 30 years in a patient's mouth. Appearance: Gold is used to create strength and durability. It not considered an esthetic restoration because of its color. Safety concerns: There are very few concerns about the safety of gold. Certain modifiers such as nickel, platinum and palladium have been questioned. Most dentists try to avoid use of nickel as many women are allergic to it having been sensitized as children by wearing costume jewelry. Advantages: -Longest lasting restoration -Gold doesn't corrode -Gold fillings are durable enough to withstand chewing forces - Gold alloys exhibit high strength and toughness that resists fracture and wear - The dentist removes the least amount of healthy tooth structure for cusp support when preparing the tooth for the restoration -Gold alloys are also gentle to opposing teeth -Resists leakage as it can be burnished or shaped on the tooth for a very tight fit. -Well tolerated by patients Disadvantages: -High Cost because of the high cost of gold and the work involved -Its metal color does not look like natural teeth -severral office visits to complete. -A temporary restoration must be worn until a laboratory constructs the gold restoration -If gold and amalgam fillings are right next to each other in your mouth, an electric current can result from interactions between the metals and your saliva, resulting in discomfort. This is called "galvanic shock."

What is a Composite resin (white filling)? A composite resin is a tooth-colored plastic mixture filled with glass (silicon dioxide). Introduced in the 1960s, dental composites were confined to the front teeth because they were not strong enough to withstand the pressure and wear generated by the back teeth. Since then, composites have been significantly improved and can be successfully placed in the back teeth as well. Composites -are not only used for restoring decay, but are also used for cosmetic improvements of the smile by changing the color of the teeth or reshaping disfigured teeth. How is a composite placed? Following preparation, the dentist places the composite in layers, using a light specialized to harden each layer. When the process is finished, the dentist will shape the composite to fit the tooth. The dentist then polishes the composite to prevent staining and early wear. How long does It take to place a composite? Because a composite is more difficult to place than silver fillings, it takes the dentist about 10-20 minutes longer to place. Placement time depends on the size and location of the cavity. Prices vary, but composites average about one-and-a-half to two times the price of a silver filling. Most dental insurance plans cover the cost of the composite up to the price of a silver filling, with the patient paying the difference. As composites continue to Improve, insurance companies are more likely to cover the cost of composites. What is the cost? Prices vary, but composites average about one-and-a-half to two times the price of a silver filling. Most dental insurance plans comer the cost of the composite up to the price of a silver filling, with the patient paying the difference. As composites continue to improve, insurance companies are more the cost of composites What are the advantages of composite? Esthetics are the main advantage, since dentists can blend shades to create a color nearly identical to that of the actual tooth. Composites bond to the tooth to support the remaining tooth structure, which helps to prevent breakage and insulate the tooth from excessive temperature changes. Disadvantages? Along with the higher cost and the extra placement time, the patient can experience post-operative sensitivity. Also, the shade of the composite can change slightly if the patient drinks tea, coffee or other staining foods. The dentist can put a clear plastic coating over the composite to prevent the color from changing if a patient is particularly concerned about tooth color. Another drawback: composites tend to wear out sooner than silver fillings in larger cavities, al-though they hold up as well in small cavities. How long will a composite last? Studies have shown that composites last 7-10 years, which is comparable to silver fillings except in very large restorations, where silver fillings last much longer than composites. Sources: AGD Vice President E. "Mac" Edington, DDS "Aesthetic Guidelines for Posterior composite Restorations," by Paul R Chalifoux, DDS The Aesthetic Chronicle 1996; "Posterior Restorations Change, Challenge and controversy," Shane N White, BdentSc, MS, MA, California Dental Journal, September, 1996.

The Hollywood smile is a dream up concept based on cartoons in the early 1900′s. Cartoonists did not want to draw in teeth so they simply penciled in a smile with a line separating the upper teeth from the lower. In reality, the two front teeth are longest and the next teeth are about a millimeter shorter. The third teeth over commonly referred to as the eye teeth or cuspids are longer. The Hollywood smile is also very white and for most people too white. The two front teeth look the largest and the adjacent teeth look one sixteenth smaller, the next look one sixteenth small than the adjacent tooth all the way to the back of the mouth. I find there are three limitations which prevent a dentist from creating a Hollywood smile including psychological, physical and financial limitations. A patients goals needs to be realistic improvement of their smile and not always the artifical smiles created by media.

WHAT IS A CAVITY AND HOW DO WE GET THEM?

A cavity is a hole in your tooth caused by acids that dissolve tooth structure until the tooth becomes so weak it cavitates, hence the word cavity. Acids occur in many foods we eat and liquids we drink such as lemons and orange juice. However, the most damaging acid comes from sugars in food, which are later converted, to acids by bacteria occurring in the mouth known as streptococcus mutans. This is especially effective at dissolving tooth structure when in the form of dental plaque. WHAT ARE DENTAL PLAQUE AND BIOFILMS? Plaque is a biofilm or a sticky layer that forms on the surface of teeth as bacteria, salivary polymers and bacteria by products or an extra-cellular matrix. For those of you who are scientifically oriented, the extra-cellular matrix contains proteins, long chain polysaccharides and lipids. If you would like to see plaque forming you could watch a great YouTube video at:

 http://www.youtube.com/watch?v=q26YhisTg7U

The bacteria that causes cavities does not occur naturally in the mouth. They are bacteria, in the form of an infectious disease usually passed from parents to child by kissing. While the microorganisms present in dental plaque are naturally present in the oral cavity, they are normally harmless. However, when this plaque is allowed to build up in a thick layer by failure to brush or floss regularly, the microorganisms nearest the tooth convert to an anaerobic state meaning they grow without oxygen. It is their growth in this condition that produces acid. Saliva is unable to penetrate the build-up of plaque and thus cannot act to neutralize the acid produced by the bacteria. Tooth structure dissolves and is not re-mineralizing. This acidic release leads to demineralization of the adjacent tooth surface, and consequently to dental decay.

TOOTH STRUCTURE CAN BE REMINERALIZED AND STRENGTHENED, BAD BREATH ELIMINATED, AND CAVITIES CAN BE STOPPED

It's a matter of taking the following five steps to healthier teeth: 1) Remove Plaque 2) Seal Holes 3) Re-mineralize Structure 4) Neutralize Acidity 5) Eliminate Bacteria REMOVING PLAQUE Plaque can most effectively be removed by mechanically scrubbing tooth surfaces with a toothbrush and dental floss. Plaque is tenacious adhering to tooth structure so toothbrush bristles and floss must wipe over a surface at least seven times. We call it the Chalifoux Rule of 7 in the office. There are some chemical treatments that help eliminate plaque and tartar build up. Unfortunately, they stain teeth and are costly. The most common chemical treatment utilizes clorhexidine solutions such as Peridex to minimize plaque but it is more commonly used to minimize gum disease and bone loss.

SEALING HOLES

Teeth form as a result of many lobes coalescing to become one unit, a tooth. The areas where lobes are joined together form pits and fissures on tooth surfaces. If these areas are deep, food may become trapped and resist cleaning by brushing. There is a high probability this will result in cavities, so it is prudent to seal them with dental sealing materials and stop food entrapment.

REMINERALIZING TOOTH STRUCTURE

Acids dissolve tooth structure by removing calcium, a process known as decalcification. These areas can be rebuilt under the right conditions. The environment must not be acidic and minerals such as fluorides found in mouthwashes, prescription toothpastes, prescription gels, fluoride varnishes and other prescription products must be present. Fluoride therapy can be effective in re-mineralizing early stage cavities, where the structure of the tooth has not yet been irreversibly compromised. It is a great way to strengthen enamel and dramatically aids in preventing cavities. It has been used to treat decay in increasing concentrations for decades. The concentration in water is 1ppm; in toothpaste 1,100 ppm; in Fluoride gel 5,000 ppm; and in new fluoride varnish the concentration is 25,000-50,000 ppm. Fluoride in water incorporates into tooth structure as it is being formed in utero but has no affect remineralizing tooth surfaces. Cavity varnish is the newest re-mineralization tool. It is applied to your teeth in a dental office and tenaciously adheres for hours after leaving. It is a very effective tool for patients who have expensive dental work to protect and for patients who are at a very high risk of cavities.

NUETRALIZING ACIDITY

Re-mineralization of tooth structure only occurs in a non-acidic environment. Rinsing with water is a good way to minimize acid formation, especially right after eating when one is unable to brush their teeth. For patients with many decalcified areas, special solutions are used to rebuild tooth structure. These solutions control the acidity or pH and provide the proper conditions to allow fluoride to rebuild.

ELIMINATING BACTERIA

It is difficult to eliminate bacteria in the mouth. Antibiotics do not travel easily through saliva and have a tendency to upset the normal balance of the oral flora. A newer and unique approach is the introduction of xylitol into the mouth. Xylitol is a natural sugar that occurs in birch tree sap and some fruits and vegetables. It cannot be broken down by bacteria to acids. Using Xylitol occupies bacteria so it cannot convert sugars. Bacteria is too busy trying to convert xylitol to be able to convert sugar. With this reduction in sugar conversion, less plaque is formed, leaving an environment far less favorable for the growth of bacteria. Xylitol comes in toothpaste, gum and candy forms. Used in the correct quantity, it is very effective in minimizing cavities and allowing fluoride to re-mineralize tooth structure.

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