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Basic Principles of Aesthetic Dentistry

Aesthetic dentistry is a treatment concept that, in addition to the practical treatment of the defective tissue, includes recognizing the cause of disease needs and suitable treatment alternatives. The Swedish dentist Per Axelsson (1978) raised the following question: is there a difference in oral health between patients who visit the dentist twice a year and those who only visit the dentist when they experience pain? The result was astonishing: actually, it did not matter whether or not patients visited the dentist regularly because both patient groups lost their teeth. However, in the years following this study, Axelsson (1981) was able to show a crucial difference: patients who visit a dental practice with an established maintenance system can go through life with healthy teeth as long as they are willing to make regular follow-up visits after completing full-mouth rehabilitation.

10 Importance of recalls

A Percentage of tooth surfaces covered with plaque (plaque index PI, upper half) and percentage of gingival units with inflammation (gingival index GI, lower half).

B Probing depth (PD) and attachment loss (AL).

C Carious surfaces, pocket depth, and attachment loss after 6 years.

Recall group

Control group (not recalled)

Caries as an Infectious Disease and How It Can Be Prevented

It is not enough to simply restore an existing cavity. Caries is an infectious disease. If the infectious disease is not treated causally, there will be no lasting treatment success. This is especially important with tooth-colored restorations, restorations in the posterior teeth, and cemented restorations. Most resin cements, composite resin cements, and resin-modified glass ionomers have a relatively low filler content. Because of this they show somewhat inferior physical properties and with time the cement is washed away at the marginal area. As a result, the risk of caries will increase at this location.

The individual risk of caries and periodontitis of each patient should be established at the beginning of the treatment. Expensive, cemented, tooth-colored restorations should not be started until the initial therapy has been completed. In addition, it should be ensured before the treatment begins that the patient will regularly attend follow-up appointments.

11 Summary

Before initiating aesthetic treatment, it is important to determine a patient's caries and periodontitis risks. The factors listed on the right should be taken into consideration.

12 Microbiological examination of the oral cavity

To determine caries activity, the quantity of Lactobacillus or Streptococcus mutans can be readily determined using commercially available microbiological kits.

Right: Level 1 = low Lactobacillus activity; Level 4 = high caries risk due to high bacterial activity.

Left: Caries risk can easily be determined using a saliva sample.

In a dental practice, aesthetic dental medicine should be offered only in connection with a preventive dental concept based on the following four levels:

—prenatal prevention

—primary prevention

—secondary prevention

—tertiary prevention

The goal of primary prevention is to secure healthy teeth and healthy periodontal tissues. Secondary prevention should prevent the recurrence of dental disease following therapy. The goal of tertiary prevention is to ensure that restorations and their restorative materials have preventive qualities. Therefore, cements that release fluoride and exhibit low solubility, such as glass ionomers, should be given preference to classic zinc phosphate cements.

Goals of Prevention

Two goals can be achieved with a well-designed preventive program:

1. In the age group below 19 years, interproximal restorations are not needed. In this age group, the use of sealants should have a high priority. If a posterior tooth requires a large restoration, the best possible material is selected after input from the patient. A small, initial carious lesion can be restored with a direct composite restoration, while a larger defect on a permanent molar can be restored with a gold restoration, based on longevity data available for these restorations. However, if instead the patient prefers a tooth-colored restoration (ceramic inlay/onlay or composite), those involved should be made aware of the increased risk of fracture and the related possibility of having to replace the restoration in the future.

Age groups with increased caries risk include 3, 7, and 8-year-olds and 13 to 15-year-olds. All teenagers undergoing orthodontic therapy belong to a very high risk group.

2. In the 20 to 50 year age group, the majority of patients should not develop any new carious lesions. Most restorations in this age group are replacements of existing fillings and crown restorations. The best possible restorative material should be selected in this case, too. It is important to select the best material to fit an existing defect rather than design a preparation to match a particular material. Ceramic restorations, particularly those fabricated using CAD/CAM technology (e.g., Cerec), force the preparation technique to be suited to the material, making the treatment less conservative. If it is a relatively small defect, the preferred materials include direct composites, gold alloys, or composite rather than ceramics.

The goal should be to save healthy tooth substance rather than to remove it for a particular restorative procedure.

13 Reduction in caries lesions among adolescents in Karlstad, Sweden, over the past 30 years

Today, the majority of children will reach adulthood without suffering from caries. Incipient carious lesions can be treated with adhesive restorative materials.

Aesthetic Dentistry—A Treatment Concept

Aesthetic treatment, like any other dental treatment, consists of four phases:

Phase 1: Systemic Phase

This phase starts before the treatment begins. Its purpose is to protect both the therapist as well as the patient. Risk patients, for example patients with diabetes mellitus and cardiovascular or blood diseases, are identified before the actual treatment starts. This step includes consultations with the physician treating the patient.

Phase 2: Hygiene Phase

The goal of this phase is to establish a clean oral cavity to secure a healthy basis for the subsequent phase.

Phase 3: Corrective Phase

Dental and aesthetic corrections are carried out during this phase.

Phase 4: Maintenance Phase

During this phase, the finished reconstructions are checked as well as the overall health of the oral cavity.

14 Systematic treatment planning

Aesthetic treatment should only be carried out upon completion of the hygiene phase. Its actual long-term success is ensured by the maintenance phase (see also Figs. 10 and 11).

The Necessity of Caring for Aesthetic Restorations

The longevity of many tooth-colored restorations can be as good as that of metal restorations. Prerequisites for success is careful planning of the treatment, skillful use of the materials, and a maintenance phase that is adapted to the individual restoration. To ensure success, the patient, the dentist, and the dental hygienist must be aware of the specific demands of a particular treatment or material.

Most aesthetic restorations consist of resins, ceramics, glasses, or a combination of these materials. Materials rich in resins (composites, resin cements, resin-reinforced glass ionomers and compomers) have a higher rate of wear and are subject to chemical degradation. Ceramics have a greater risk of fracturing and may be etched by some oral hygiene articles. Before beginning any treatment, the dentist and the patient should discuss the advantages and disadvantages of the different restorative materials and coordinate professional and home-care oral hygiene procedures accordingly.

Professional Tooth Cleaning in Patients with Aesthetic Restorations

It is very important that the dental hygienist and the entire dental practice team use established methods when performing professional tooth cleaning, scaling, root planing, polishing, and different fluoride applications that are needed for existing restorations. Removal of plaque, tartar, and bacterial toxins from root surfaces can be carried out manually or mechanically.

After the first examination, which is executed by the dentist in collaboration with the dental hygenist, an individual treatment plan is drawn up. The plan is developed for the patient, based on the seriousness and type of the patient's disease.

Manual Scaling

Manual scaling performed using metal curets does not damage a bonded restoration to the same extent as ultrasonic scales, assuming that the therapist takes certain precautions. These precautions include first identifying the margins of the restoration. Dentists and the dental hygienists have learned to carry out scaling and root planing with the cutting edge of the curet in the periodontal pocket and in firm contact with the tooth surface, moving the curet in a coronal direction. Such a technique causes the curet to slide over the margins of the restoration and could result in parts of the restoration being torn off and the restoration, with its resin-filled marginal gap, loosening and eroding.

A simple modification of this scaling technique is to move the scaler along and parallel to the restoration margin. By doing so, less damage is caused in the marginal area. Scaling and root planing at the margin of bonded restorations must be performed carefully and very consciously.

—Recommended curets: Gracey curets

—Working direction: horizontal

—Avoid scalers because they generate poor tactile feeling.

15 Using curets on nonrestored teeth

The usual curet technique involves the curet being inserted into the sulcus and pulled in a coronal direction, with the cutting edge along the tooth surface. The tooth surface can thus be scaled and planed. This action can only be recommended for nonrestored teeth, as otherwise there is a danger of restoration margins being damaged.

16 Using curets on restored teeth

The curet should not be moved along the root in a coronal direction, but in a direction parallel to the restoration margin. This prevents damage to the margins of the restorations.

Scaling using Powered Instruments

Scaling is also performed with sonic and ultrasonic devices. Many dentists and dental hygienists use such scalers, since they can remove calculus more quickly. At the same time, therapeutic irrigation of the sulcus can be performed with the spray of the scaler.

If handled improperly, ultrasonic devices can damage all types of restorations. They can chip ceramics, cause abrasion of composites, increase the surface roughness of all restorations, and destroy the adhesive joint between tooth and restoration. Because of these drawbacks, sonic and ultrasonic instruments should be avoided in patients who have several bonded restorations. If necessary, however, the appliances should be used with great caution, and margins of tooth-colored restorations should not be touched.

Consequently, it is necessary to inform patients with aesthetic restorations that they should have their teeth cleaned professionally more frequently to avoid a large accumulation of plaque, calculus, and stain and it does not become necessary to use larger equipment to remove these mechanically. If the patient visits the practice at shorter recall intervals, less tartar will accumulate and, consequently, less aggressive methods are needed to remove it. Thus, manual scaling becomes simpler and less time-consuming. The risk of injurying a restoration margin decreases. At the same time, it is possible to check and detect secondary caries lesions at an early stage.

17 Ultrasonic devices and composites

This composite surface has been destroyed by an ultrasonic device. The result is discoloration and accelerated degradation of the restoration.

18 Ultrasonic devices and ceramics

Ultrasonic scalers can damage all-ceramic crowns, veneers, and inlay margins.

Air Polishing Devices

Discolorations are usually removed by polishing, conducted with rotating instruments, brushes, and rubber cups. Additionally, air-powered abrasive devices are also available. The air polishing abrasive appliances (CaviJet, ProphyJet, AirFlow, and AirScaler) are very efficient at eliminating dark stains in concave tooth surfaces and in areas that are difficult to access. However, their abrasive power prohibits them from being used near restorations of any types. Their use should be exclusively restricted to natural, unfilled tooth surfaces.

Polishing Teeth

The best method of polishing tooth surfaces is with rotating instruments and prophylactic pastes. It should be noted that the prophylactic pastes to be used should have low abrasivity. Any rubber cups that are used should be made of a very soft, low abrasive material. Many of the relatively hard rubber cups and most commercial prophylactic pastes are too abrasive for composite surfaces and resin cement margins.

Avoid using ultrasonic devices for removing calculus and also air polishing units. Finishing strips and disks must also be used with great caution.

Since, ideally, a good composite restoration is invisible, the margins of the restoration should be marked on the treatment card.

Recommended polishing pastes:

—Proxyt

—CCS Prophylaxepaste; RDA 40

Fluoride Treatments

At each recall, the patient's teeth should be fluoride treated. For this purpose the dental hygienist uses stannous, and sodium fluorides. Stannous fluorides should not be used with tooth-colored restorations because they can etch their surfaces. The problem with such etching is especially pronounced with ceramic surfaces. If an IPS Empress veneer whose surface is painted a great deal is exposed too frequently to an acidic stannous fluoride, the ceramic surface can gradually be attacked and the surface color can be dissolved. Therefore, as a general rule, neutral sodium fluorides should be used in the practice.

Recommended fluorides:

—Blend-A-Med fluoride gel

—Oral-B Neutra-Foam

—ACT dental rinse

19 Effect of air abrasives on restorations

The surface of this composite restoration (hybrid) has been damaged by the use of air abrasive equipment.

Left: Abrasion of the ceramic surface using air abrasive equipment.

20 Influence of various polishing techniques on restorations

A deep groove has been polished into this composite surface by using a prophylactic rubber cup and an abrasive polishing paste.

left: Abrasion of a microfilled composite surface with a ProphyJet.

Home Care—Patients with Aesthetic Restorations

A patient with tooth-colored restorations should be given clear instructions by the dentist or dental hygienist on how to perform oral hygiene at home. Given the quantity of products offered in drug stores, it may be difficult for patients to select the right toothpaste and toothbrush for their home care.

Toothbrushes

Patients with many tooth-colored restorations must use very soft toothbrushes. The toothbrush can easily abrade composite restorations in particular.

Some patients have difficulties with plaque control and therefore need to be recalled more frequently.

If patients have problems with their oral hygiene, it may be helpful to recommend an electric toothbrush. Electric toothbrushes with rotating soft bristles are reliable and effective.

Toothpastes

A large number of different products are available, including toothpastes that specifically remove tartar, those that are good for the gingiva, and those that whiten the teeth. Toothpastes are available as pastes or gels. Most toothpastes contain fluoride, while some also contain baking soda and peroxides. Patients should be informed that gel toothpastes are less abrasive than pastes. A toothpaste with low abrasivity should be used. Often, pastes that make teeth white are more abrasive and should therefore be avoided. Toothpastes containing stannous fluoride can lead to discoloration of composite surfaces. Colgate Gel is an example of a gel toothpaste that has a low abrasivity and contains sodium fluoride.

21 Etched ceramic surface

This ceramic surface was treated with an amine fluoride gel. Amine fluoride and stanuous fluoride with a very low pH value are present in many toothpastes and prophylactic pastes. A sodium fluoride toothpaste with neutral pH value should preferably be used on ceramic restorations.

22 Samples of oral hygiene products

A large variety of oral hygiene articles are available in supermarkets. The dentist or dental practice staff must give clear advice to patients with aesthetic restorations on how to choose suitable oral hygiene products.

Mouthwashes

Many mouthwashes have a very high alcohol content. The alcohol can soften resins and after some time they can cause the resin surface to dissolve. Therefore, nonalcoholic products should be used.

Generally, two groups of mouthwash are recommended:

—mouthwashes with fluoride

—mouthwashes with an antiplaque additive

Mouthwashes containing chlorhexidine are not recommended. Chlorhexidine causes discoloration of the tooth surface. This discoloration increasingly appears at the bonded sites and on resin surfaces and is very difficult to remove. If mouth rinses containing chlorhexidine must be used, local application of a gel is recommended to minimize the discoloration.

Additional Aids

Many patients use dental floss, proxabrushes, and toothpicks. The use of dental floss is usually completely harmless if the patient has been taught a proper technique by the dental hygienist. The use of toothpicks is not recommended. An oral irrigator is quite safe, as long as no chemicals are used that discolor or dissolve resin surfaces.

Diet

The patient should receive nutritional advice including a list of foods that often cause tooth surface discolorations or dissolve ceramic surfaces. Patients will only rarely change their diet. They should, nevertheless, know which nutritional parameters may change the color of tooth surfaces, particularly resin surfaces or cement joints.

Smokers

Cigarette smoke leads to a pronounced discoloration of the tooth surface, particularly of resin surfaces. Smokers should be recalled frequently.

Oral Habits

Bruxism, chewing of ice cubes, and chronic biting on objects such as toothpicks, fountain pens, etc. lead to the loss of tooth substance. The patient must be made aware of this.

If the patient cannot break these habits, damage can occur not only to natural dentition, but also to any restorations. The patient should be informed, verbally and then in writing, of the necessity of attending recall sessions at the practice at shorter intervals due to particular life-style factors (smoking, oral habits, dietary factors, etc.).

23 Recommended oral hygiene aids for patients with all-ceramic restorations

In principle, patients should use as soft a toothbrush as possible. Many patients with high aesthetic claims show pronounced abrasive defects. A suitable power toothbrush can prevent further progression of such abrasive defects. Additionally, a low abrasive toothpaste with neutral pH value containing sodium fluoride should preferably be used. Mouthwashes containing chlorhexidine should be avoided because of their strong tendency to stain the teeth.