Why do cavities sometimes develop along the gum line?

Although most of the cavities that dentists find in children and young adults are either pit and fissure decay(located in the occlusal surfaces of posterior teeth) or interproximal decay, located immediately below the contact area, another common place to find decay is along the gum line of teeth.

Gum line caries may be caused by a number of factors, including excessive consumption of sugary foods, sodas, bulimia, acid reflux, lemon sucking, dry mouth and general poor brushing technique. Caries usually starts with acid dissolution of tooth structure and invasion of the tooth structure by bacteria. Normally smooth surface enamel is fairly resistant to caries, especially when it is cleaned well by brushing . Sometimes even 'good brushers' can have areas that they find hard to keep clean. It is not terribly unusual to find decalcifications on the buccals of upper second and third molars, since these tooth surfaces are sometimes hard to get to with a toothbrush.

Often children both, young and adolescent, don't spend the time needed to brush their teeth systematically. Many just distribute their tooth paste around their mouths in a rather random fashion and assume that the toothpaste will 'magically' clean their teeth. This is not the case, since toothpaste doesn't actually do much cleaning. Instead the tooth brush bristles are doing most of the cleaning and they should contact all accessible tooth surfaces.

Older patients( over seventy) often present with root caries. These carious lesions tend to be located on roots of teeth that are exposed as a result of gingival recession. Cementum normally covers root surfaces, but often this thin coating get denuded over time and exposed dentin can be more at risk for decay especially, for seniors, who tend to experience the double whammy of both dry mouth and a decline in oral hygiene habits. These carious lesions can be a real challenge for dentists to restore since they can be in difficult to reach areas and restorations can experience recurrent decay afterwards.

Accordingly, to restore root caries, I almost always use high fluoride releasing restorative filling materials, such as glass ionomer formulations(Gc Miraclemix, Gerastore, RelyX) to restore these lesions, since they offer some protection from future recurrent decay.

What is the difference is between a free gingival graft and a connective tissue graft?

This is a guest post written by my good friend and colleague Dr Philip Pack, an excellent periodontist practicing in New York City. I have known him for many years and often pick his brain on all matters of a periodontal nature.

Patients are really not sure what the difference is between a free gingival graft and a connective tissue graft. Patients know that both grafts are taken from the palate but are otherwise confused.

The free gingival graft is an excellent choice where the goal is to increase the amount of hard gum tissue (keratinized tissue) around a tooth. It is best used in non-esthetic areas where root coverage is not the objective. Increasing the amount of keratinized tissue will decrease the likelihood of further recession.

The connective tissue graft is the best choice where there is an esthetic problem or hot and cold sensitivity. It is the procedure of choice for covering exposed roots and obtaining a good tissue blend. A good tissue blend means that it is difficult to distinguish the graft from the adjacent tissue.

The tissue harvested from the palate for a free gingival graft is from the surface and is rectangular in shape. The connective tissue graft is also rectangular but is harvested from underneath the surface tissue. The incision for the connective tissue graft is a narrow straight line and usually heals more quickly because it is smaller.

Both procedures have been performed for many years and have stood the test of time.

Why does dentistry cost so much?

While Dentists are fortunate to be involved in a helping profession, they are also small businessmen who run a private for profit business.

Getting started in dentistry is expensive and can leave young dentist's with a large debt load of hundreds of thousands of dollars in debt. Opening a dental office can also be
expensive. Dental offices are costly to build and even well established dentists can feel financial pressures.

Most patients expect their dentists to stay current with both their continuing education and maintain a modern dental office that features current dental equipment. Also, since dentistry is a service profession, successful dentists must employ a professional and friendly staff in order to deliver their dentistry and make their patients comfortable.

Salaries and benefits for well trained dental staff can be expensive since they expect compensation that is competitive with the market place and they most talented employees can easily find work with other dental or medical facilities. Salaries and employee benefits for dental offices can account for about 28 percent of operating expenses.

Most patients demand that their dentist stay current both with their continuing education and expect that their dentists use first rate materials. Similarly dental laboratories that dentists employ to achieve create beautiful and well fitted dental restorations are not inexpensive either.

It is not surprising that that a high percentage of any dental fee goes to paying operating expenses. Most dental offices have operating overheads of 60-70 percent or more. This means that dentists are left with at best 40% of every dollar they bill out. For younger dentists much of this money is used to satisfy their educational debt service.

Still, when all is said and done,most dentists do manage to maintain a good standard of living and in my opinion most are motivated by a desire to help their patients maintain a high level of dental health. I believe most work hard at their professions and earn their incomes.

What cement do you use to cement your implant crowns with?

Although I sometimes use a more permanent cement, usually I use tempbond, a temporary cement that is radio-opaque. Residual excess cement can be irritating when left around an implant restoration. It can even cause an infection if left undisturbed for a number of years. Originally I started using temporary cements because I thought it would make it easier to remove an implant crown in the event that an implant abutment became loose, but even temporarily cemented implant crowns can be difficult to remove safely using GC forceps (pliers used to remove crowns). I still use it routinely because it has other advantages.

Radio-opaque temporary cement is a good choice since caries (tooth decay) is never an issue for implant restorations and excess cement can often be visualized a post-op radiograph. More importantly, it is necessary to remove all excess cement after cementing any implant crowns, and tempbond is fairly easy to remove and actually tends to be water soluble.

If an implant crown is well fitting temporary cement usually holds the crown well for many years. If a crown does come out, it can be recemented.

Why do you use so many burs?

Burs are the term a dentists use for the small drill bits that fit in their drills. Dentists need to have a broad assortment of burs. Some are carbides and some are diamonds. Commonly, carbides are used for preparing fillings. They often are used only once and then thrown away. They have tiny fluted blades that are almost as sharp as razor blades. When new, they cut fast and true, with little hand pressure. After only a single use they can become dull and no longer cut efficiently.

Diamond coated burs also used for our preparations and can be purchased in several different 'grits' . I use diamond burs for my crown preparations and for shaping my bonded restorations. Diamonds are more expensive than most carbides, but can easily be sterilized and still retain most of their cutting ability.

Burs come in many different shapes and they can be used to shape teeth when a dentist is 'sculpting his preparations. Teeth come in many different shapes and sizes tand may require longer, shorter, thinner or wider burs in order for a dentist to achieve an excellent result.

While some dentists manage to provide their dentistry with only a small variety of burs, I prefer to select from a large variety, so that I can find just the right 'tool' for each situation. I believe that it helps me create predictably excellent restorations.

My crown came out. Can It be recemmented?

The answer is sometimes. In my New York dental practice, if a patient comes in with a crown that has come out I carefully inspect the tooth and the inside of the crown. I look for recurrent decay on the tooth structure holding the crown. If the crown has decay around the margins of the crown it is usually a bad idea to recement the crown after removing the decay since it will not fit properly.

I also look inside the crown to see whether the cement remains inside of it or has it experienced " cement wash out". If the inside of the crown has black stain it probably indicates that the crown was "leaking" for some time prior to coming out.

If the tooth is ok and not decayed, I remove all the cement inside the crown, sandblast the internal part and use GC fitchecker to check its fit. If I like the fit I take a check radiograph and if it seems appropriate I will recement it with a permanent cement.

Sometimes recementation works well, but other times the crown can come out again. This can happen because the crown as it was fabricated doesn't have sufficient retention to stay in permanently.

What are some good dental blogs?

Onlineuniversities.net has a good post giving their list of 50 Excellent Dental/Oral health blogs. The list provided is extensive and informative. I am proud to report that "Ask Dr Spindel" headed the list. Thank you for this recognition. When I first started writing this blog it had 5 visitors every day--all of them me! Last month the blog had over 6,000 unique visitors. It is my hope that the information presented will be found by people searching for answers to their dental questions and that the information presented will be helpful. Comments are welcome and questions may be forwarded to me by using the contact page on my dental office website.

What kind of crown will not ever show a grey line at the gum line?

The grey line that some crowns show when a patients gums receed is usually from the metal substructure of porcelain fused to metal crowns. Although these crowns can be durable and are often a good choice in the posterior region, they are not the most esthetic for single crowns for anterior teeth.

Dentists can choose from a number of crowns that are metal free. In my New York dental practice I primarily use two types of crowns to acieve optimal esthetics in the anterior region. If strength is a priority I use Lava crowns. These crowns are good looking, have no tell tale gray metal margin and tend to be tough. They have a Zirconium core that supports the porcelain.

The best esthetics are achieved with all porcelain crowns that are bonded with composite luting cement. These can have the highest degree of translucency and are therefore the most 'life like'. They are more breakable than Lava crowns, but usually work well for anterior tooth restorations (in my experience).

Porcelain veneers can be a good option for many anterior teeth, since they leave most of the lingual tooth structure intact, but they need sufficient remaining enamel to bond to in order for them to work well. Also they are usually not as tough as the two types of crowns I mentioned. The sole exception would be a patient wtih a deep over bite. Often this type of bite puts a lot of pressure on the linguals of crowns and can cause breakage or loosening of a crown. Porcelain veneers work better for patients with these bites.