Chapter 26 Technology and Esthetics

Section A Minimally Invasive Dentistry: Dental Procedures and Technology

Edward Lynch, Fay Goldstep, George Freedman

Relevance of Minimally Invasive Dentistry to Esthetic Dentistry

The less destruction of tooth structure, the more conservative the preparation. The more of the original tooth structure that can be maintained, is generally more esthetic. In dealing with a carious occlusal pit and fissure lesion that extends into dentin, management with a minimally invasive approach is preferable—for example, using the SS White fissurotomy burs (SS White Burs, Inc., Lakewood, New Jersey) (Figure 26-1, A) and exposing the dentin, plus subsequent treatment with ozonation of tooth surface and rinsing with ozonated water (Figure 26-1, B). The disinfection of remaining carious dentin is possible as long as the lesion is relatively superficial. An acid-etching technique (Etch-Rite, Pulpdent Corporation, Watertown, Massachusetts) is then used on the enamel (Figure 26-1, C), followed by a use of single-bottle seventh-generation system (Bondforce, Tokuyama Dental America, Inc., Encinita, California) for bonding to enamel and dentin (Figure 26-1, D). After light polymerization (Figure 26-1, E), an appropriate flowable composite resin (BEAUTIFIL Flow Plus, Shofu Dental Corp., San Marcos, California) can be inserted into the cavity (Figure 26-1, F). This is a very minimally invasive approach that produces end results that are esthetically pleasing for the patient (Figure 26-1, G).

FIGURE 26-1 A, SS White Fissurotomy bur in fissure to the depth of the dentin. B, Rinsing the tooth surface with water. C, Etching the tooth surface. D, Applying the adhesive (Tokuyama Bond Force). E, Light polymerization. F, Restoration with BEAUTIFIL Flow Plus. G, Completed fissure restoration.

(Inset D courtesy Tokuyama Dental America, Encinitas, California. Inset F courtesy Shofu Dental Corporation., San Marcos, California.)

Patients who are esthetically oriented are generally more up-to-date with modern health concepts and philosophies. Dentistry has moved away from the destructive template approach that involved cutting prescribed shapes into the teeth (Figure 26-2). Modern dental practice is much more focused on a disease-oriented approach, in which the diseased tissues are removed and only those modifications that are absolutely necessary to improve the longevity of the restoration are made to the cavity site (Figure 26-3).

FIGURE 26-2 Traditional preparation class II form.

FIGURE 26-3 Conservative Clark class II preparation.

Brief History of Clinical Development of Minimally Invasive Dental Procedures and Technology

The earliest perhaps inadvertent attempts at esthetic dentistry or minimally invasive dentistry were made by Michael G. Buonocore in the 1950s (see Figure 8-16). He was the first to etch teeth and to begin the process of bonding to tooth structure, which is inherently more conservative of teeth than preparing shapes that physically retain amalgam. As this approach progressed from enamel etching to the inclusion of dentin etching/conditioning in subsequent years, it became more widely used, so that by the turn of the twenty-first century over 50% of North American posterior restorations were performed with adhesive procedures. Subsequently the single-bottle, seventh-generation adhesives were developed. Other innovative technologies helped to ensure that the surface to be restored was relatively free of bacteria that cause decay, or at least less inclusive of those bacteria (Figure 26-4).

FIGURE 26-4 Consepsis syringe.

(Courtesy Ultradent Products, Inc., South Jordan, Utah.)

The philosophy is now even more conservative. The infected dentin is managed with ozone and photoactivated disinfection (PAD). This allows the operator to dramatically reduce the number of microorganisms remaining in the retained dentin, which can then be infiltrated with adhesives that bond to this surface. This process is most conservative with direct composite restorations. Ozone can penetrate to a somewhat deeper sub-surface level than PAD. Ozone is available in a gaseous form, such as that provided by the HealOzone system (Curozone GmbH, Wiesbaden, Germany) (Figure 26-5) in action and in aqueous form with ozonated water.

FIGURE 26-5 HealOzone system on tooth.

PAD is available commercially as well. The most common system used is Aseptim Plus (SciCan, Ltd., Toronto, Canada) (Figure 26-6, A). A dye that attaches to microorganisms (Figure 26-6, B) is placed on the prepared tooth surface then is irradiated with a light-emitting diode (LED) light to effectively kill the microorganisms near the surface (Figure 26-6, C).

FIGURE 26-6 A, Aseptim Plus. B, The dye that will be placed on the prepared tooth. C, Tooth irradiated with a light-emitting diode (LED) light to kill the microorganisms near the surface.

(A courtesy SciCan, Ltd., Toronto, Ontario, Canada.)

The history of minimally invasive dentistry has been a process whereby the surgical approaches of the past that focused on removing all diseased or questionable tissues and replacing them with restorative materials have been replaced by a philosophy that allows the on-site management and treatment (where possible) of diseased tissues. Increasingly treatment is aimed at retaining as much natural tissue as possible as an integral part of the permanent restorative process.

Relating Function and Esthetics

Maintaining the natural tooth structure assists in both function and esthetics. For example, if an operator is removing caries from a mesial-occlusal-distal (MOD) cavity in the upper first premolar, and if the base of the retained buccal cusp is supported by more conserved tissue, clearly that buccal cusp has greater strength than that allowed by the traditional invasive approach of cavity preparation, which undermines and weakens the remaining cusp (Figure 26-7). Natural tooth structure is better than the best restorative materials available and supersedes any synthetic material the dentist can place. Generally, if the dentist can maintain the natural occlusion, the natural form and shape of the tooth, and the functional outline of the dentition and soft tissues, the health of the patient’s oral environment will be better and more easily maintained over a longer term.

FIGURE 26-7 A, The unprepared tooth has the greatest strength. B, The undermined buccal cusp of the traditional invasive cavity preparation is rather weak and can fracture under pressure even after restoration. C, The conservative preparation leaves more supportive tissue under the buccal cusp, making pressure fracture after restoration less likely.

Clinical Considerations

Indications

The indications for minimally invasive dentistry include every preparation and intervention that an operator carries out. Minimally invasive techniques are not solely applicable to pits and fissures but also deal with overall health and patient management. Even deep carious lesions can be managed to avoid traumatic exposure of the pulp or even potential further damage to the pulp through additional heating, desiccation, or trauma associated with operative procedures in close proximity to the pulp (Figure 26-8).

FIGURE 26-8 Removing deep caries with the Smart Bur II (Wehmer Corporation, Lombard, Illinois).

Contraindications

Minimally invasive dentistry is both a clinical approach and a philosophical one. In practical terms, it is a clinical approach because it is something that every dentist aims to achieve for every preparation for each patient. However, the philosophical approach of non–minimally invasive dentistry has been predominant for over a century within the dental profession. It predated the modern pharmaceutical approach to managing infected tissues. In the past, a number of studies have shown that any infection remaining in the tissues could progress, thereby leading to ongoing problems beneath restorations (Figure 26-9). Caries may progress, with all the attending implications. Of the pharmaceutical approaches to management, the two most notable are ozone (gas or ozonated water) and PAD. These approaches destroy or reduce the pathogenicity of the cariogenic flora remaining beneath cavity preparations. This allows a much more minimally invasive approach. This treatment modality is not limited to the management of caries or cavity preparations; it can be used in endodontics, periodontal therapy, and other areas.

FIGURE 26-9 A, Occlusal decay is removed with high-speed and low-speed burs, inadvertently leaving healthy-appearing but affected dentin toward the buccal area of the cavity floor. B, The affected dentin is sealed over by the layered steps of the composite restorative material. C, The affected dentin, still harboring bacteria, begins to re-decay along the tooth-restorative interface, eventually expanding and infecting the pulp.

Material and Assessing Options

Ideally the dentist must properly isolate the operative area, which requires selecting from the various available isolation methods, including the rubber dam technique where appropriate. It is also necessary to develop effective visualization access, typically involving magnification and illumination.

The dental team, including every single professional member, has both a responsibility and a desire to deliver the best care possible to each and every patient. The experience of clinical practice and continuing education tends to improve the quality of this care throughout the dentist’s career. The clinical success in the delivery of dental care, however, is dependent on many factors including visual acuity and manual dexterity. Enhancing the diagnostic and clinical armamentarium in ways that enhance the eyes and hands of the operator benefits both patients and dentists tremendously.

Clinical dentistry can be a rather difficult occupation. The oral cavity is not a treatment-friendly space; it is small, has restricted access with numerous interfering oral structures, and is generally quite dark. Seeing minute details (during diagnosis or treatment) and visualizing procedures in progress can be both difficult and stressful. The improperly positioned patient’s head can cause significant physical discomfort to the practitioner seeking better visual access and may in time cause the dentist physical damage that may impede the continued practice of dentistry (Figure 26-10).

FIGURE 26-10 Dentist leaning over patient at an awkward angle.

Magnification

Magnification provides the means to alleviate many of these problems and concerns and allows the dentist to practice more comfortably while ensuring that dental procedures can be delivered at the most exacting level (Figure 26-11).

FIGURE 26-11 Practitioner wearing magnification loupes.

(Courtesy Orascoptic, Middleton, Wisconsin.)

The most significant advantages offered by magnification loupes are visualization, illumination, isolation, and preparation.

Visualization

Improved visualization of minute yet significant dental detail simplifies diagnosis and enhances clinical treatment. The dentist using magnifying loupes can examine both hard and soft tissue surfaces in more exacting detail, thus often diagnosing problems at an earlier stage than previously possible. Earlier diagnosis benefits the patient through more conservative, less invasive treatment (Figure 26-12).

FIGURE 26-12 Distant (A) and close-up (B) views of the same structure.

Fortuitously, magnification loupes force the operator into a more ergonomic posture, reducing back and neck strains (Figure 26-13). A dentist who is using properly fitted magnification loupes is required to view the oral cavity and to operate from a more ergonomic and healthier sitting position. There is less stress on the back and neck muscles, reducing strain and contributing to more comfortable and productive working sessions. Magnification is responsible for reducing eyestrain by providing a clear and magnified view of the working area. Decreased eye fatigue contributes to a more satisfying clinical practice, particularly toward the end of a working day or a long working week. In addition, the improved clinical visualization allows more precise and less invasive treatment.

FIGURE 26-13 Good (A) and bad (B) posture of a practitioner.

Esthetic and cosmetic procedures call for invisible margins and tooth-restorative interface transitions. These technique-sensitive, yet critical, features are far easier and less demanding to develop when the visual working field is enhanced to twice normal (or greater) size. If the margin seems to “disappear” when magnified, then it will certainly not be visible to the naked eye. The fine internal and external colorations and characterizations that are required for “invisible” margins are virtually impossible to achieve without appropriate magnification (Figure 26-14).

FIGURE 26-14 Close-up views of visible (A) and invisible (B) margins.

A generation ago, magnification was primarily targeted at older practitioners whose age-related eyesight changes were making routine clinical procedures increasingly difficult to accomplish. These individuals required mechanical vision modification in order to keep practicing dentistry, and loupes, such as they were at the time, fit the bill. Then, cosmetic dentists, who were fanatically fussy about margins and other minute clinical details, began to avail themselves of the esthetic advantages offered by working under magnification. Periodontists and endodontists quickly followed suit. Today magnification is routinely introduced to dental students while they are in their formative years of dental school.

As magnification has become more mainstream in the dental profession, it has raised the bar in the assessment of restorative procedures. Current standards of care demand better materials, better techniques, and better self-evaluation. The twenty-first–century practice finds dentists at every age and stage, in general practice and in specialties, using magnification to enhance their visual acuity, to see more easily, and to diagnose earlier, more effectively, and more accurately. Today, clinical treatment under magnification is part of the design concept for most new materials and techniques.

Illumination

The science and art of illuminating the operative site have advanced rapidly in recent years. Dentists, like medical surgeons, have found that maximizing visual acuity at the work site not only is important, it is essential (Figure 26-15). Suitable lighting provides much-improved diagnostics, greatly enhanced treatment opportunities, and better treatment outcomes. Vision and visibility in the oral cavity are always major concerns. Hands, instruments, or even a slight movement of the patient’s head can often obstruct the overhead dental light. Fiberoptic light handpieces have been the standard of care for several decades, and most dentists will not consider high-speed tooth preparation without targeted illumination of the operative site (Figure 26-16). Although in-handpiece lights are effective in illuminating the immediate working area, often a larger sphere of visibility is needed (Figure 26-17). In addition, as dental professionals get older, their eyes require more light to see and work effectively. Increasingly they have begun to use illuminating headlamps. Earlier lighting models were heavy, bulky, wired (to the battery), and cumbersome. The innovative and very convenient solutions to illumination problems inside the oral cavity consist of LED bulbs that provide 500 foot-candles of light intensity or more. Best of all, the headlight’s weight on a standard clip is less than 1 oz. Headlights are also effective clinical treatment adjuncts for hygienists as well as others on the dental team.

FIGURE 26-15 Practitioner wearing loupes with illumination.

FIGURE 26-16 Fiberoptic handpiece.

FIGURE 26-17 A, Odyssey Mini 3 Watt LED. B, DentLight Nano Loupe Light.

(A courtesy SurgiTel, Ann Arbor, Michigan. B courtesy DentLight, Richardson, Texas.)

Isolation

There are typically three major problems when working in the mouth: (1) the lack of visibility of the teeth or soft tissues, (2) the physical interference of the tongue and cheeks in the work areas, and (3) the presence of copious amounts of saliva that tends to flood surfaces just when they need to be dry. In fact, most of the benefits of four-handed dentistry involve improved isolation and moisture control in the working area. The Isolite system (Isolite Systems, Santa Barbara, California) (Figure 26-18, A) isolates the working field by keeping away the tongue and cheeks. It is attached to the high-volume suction port and aspirates both excess saliva and coolant water from the handpiece. It also provides bright, shadowless illumination inside the mouth through the light distribution system in the Isolite mouthpiece (Figure 26-18, B). The light source is external, and the brightness can be adjusted as per the needs of the operator. The single-use mouthpiece is readily inserted into the patient’s mouth, and patients find the mouthpiece very comfortable as resting the teeth on the bite block makes it easier to keep the mouth open for extended periods during procedures. The illumination is delivered into the mouth using an LED light source; there is no electrical current or any danger of shock in the mouth. The continuous aspiration of both the buccal and lingual sulci keeps the field dry and the working area clean and clearly visible. The Isolite mouthpiece is flexible and acts as a single-unit replacement for numerous isolation, illumination, and aspiration devices.

FIGURE 26-18 A, Isolite system provides continuous illumination, aspiration, and retraction. B, Lighting the patient’s oral cavity from within the mouth.

(Courtesy Isolite Systems, Santa Barbara, California.)

Preparation

Clearly the tools that are used to prepare the cavity are very important. Air abrasion must be well directed and aimed into the cavity with appropriate high-aspiration suction so as not to produce excessive debris around the rim of the preparation (Figure 26-19, A). The PrepStart H₂O (Danville Materials, San Ramon, California) (Figure 26-19, B) and the RONDOflex (KaVo Dental, Charlotte, North Carolina) (Figure 26-19, C) are the two highest-ranked air abrasion systems for use in cavity preparations, particularly in pits and fissures (Figure 26-19, D and E).

FIGURE 26-19 A, Air abrader on teeth. B, The PrepStart H₂O. C, The RONDOflex. D and E, Comparison of air abrasion preparation and fissure preparation.

(B courtesy Danville Materials, San Ramon, California. C courtesy KaVo Dental, Charlotte, North Carolina.)

The SS White Fissurotomy bur (Figure 26-20) is a novel approach to ultraconservative dental treatment. The shape and size of the bur are designed specifically for the purpose of treating small, incipient, and pit and fissure lesions. The head length of the bur is 2.5 mm, the average thickness of occlusal enamel, allowing the dentist to limit the bur tip to cut to just below the dentino-enamel junction (DEJ) and not further into the dentin (conservation). The tapered shape of the bur (visualization) allows the cutting tip to encounter very few dentinal tubules (patient comfort) at any given time and has been designed to minimize heat buildup and vibration. Because the cutting of the Fissurotomy bur is restricted largely to enamel, patient discomfort is minimized and the need for local anesthetic is eliminated in most cases. The Fissurotomy bur is far less invasive than similar length carbide and diamond burs. Traditional cutting burs remove far more enamel at any depth of cut and are designed to access caries that has progressed well beyond the DEJ, whereas the Fissurotomy bur has been anatomically designed to enlarge the fissure and eliminate small caries without removing excessive healthy enamel or dentin.

FIGURE 26-20 The SS White Fissurotomy bur.

The SS White Great White bur (Figure 26-21) is an excellent instrument for generating conservative preparations, particularly in posterior teeth. Its highly dentated surfaces quickly and effectively cut tooth structures, amalgam and composite resin, and restorative metals. Its geometric configuration is highly suitable for developing ideal cavity preparations for class I and II posterior composite resins. The Great White bur does not grab, catch, stall, or break in harder-to-cut materials such as amalgam, composite, and semi-precious and non-precious castings.

FIGURE 26-21 SS White Great White bur.

The HealOzone system (Curozone, Wiesbaden, Germany) (Figure 26-22) produces ozone that safely kills cavity-causing bacteria in and on the tooth (Figure 26-23). To prevent potential lung inhalation, it is important to follow manufacturer directions. Ozone treatment (as seen in the HealOzone system) is highly effective in managing superficial infected dentin.

FIGURE 26-22 The healOzone ×4.

(Courtesy Curozone GmbH, Wiesbaden, Germany.)

FIGURE 26-23 Principles of operation for healOzone ×4. 1, oxygen suppy; 2, air supply; 3, air dryer; 4, differential pressure sensor; 5, ozone generator; 6, tooth cup; 7, ozone; 8, handpiece; 9, tubing; 10, moisture trap; 11, ozone neutralizer; 12, vacuum pump.

(Courtesy CurOzone GmbH, Wiesbaden, Germany.)

The restoration process involves the effective elimination of remaining bacteria on and in the dentinal surface, followed by a single-component adhesive system that can manage enamel and dentin simultaneously. The restorative material buildup for the single-surface occlusal cavity is well documented.

Single Surface Occlusal Cavity

As previously documented in Figure 26-9, A, the majority of the decay is removed. Often, undetectable surface bacteria remain that can cause further decay after the restorative process (Figure 26-24, A). Ozone gas can be used to kill bacteria in the surface dentin layers (Figure 26-24, B). Alternatively, PAD can also be used to destroy the remaining bacteria (Figure 26-24, C). After either of these treatments or independently, ozonated water can be used in rinsing the cavity preparation to provide a bactericidal effect (Figure 26-24, D). Then a seventh-generation adhesive is applied to the prepared surfaces, air dried, and polymerized (Figure 26-24, E). The composite restorative material is placed into the cavity in small increments (up to 2 mm) and polymerized (Figure 26-24, F). The composite material is built in increments to the occlusal surface, polymerized at every step, and then finished to full occlusal contour and esthetics (Figure 26-24, G).

FIGURE 26-24 A, The visible decay is removed with high-speed and low-speed dental burs. Affected dentin may remain in spite of the best preparation efforts. The cavity preparation is disinfected with ozone gas (B), photoactivated disinfection (C), and/or ozonated water (D). The disinfected cavity (E) is now restored with adhesive and layered composite materials (F and G). Because there are no live bacteria left in the formerly affected dentin, this step reduces the incidence of re-decay.

The Aseptim Plus unit (see Figure 26-6, A) is a PAD device that infiltrates the cell wall using tolonium chloride dye. PAD is discussed thoroughly in Section D of this chapter.

Innovative Elements

The innovative elements include all the new technologies in magnification, illumination, and isolation.

Magnification

Lighter, more comfortable, and easier to adjust loupes have made magnification a practical operation for the practitioner. Improved optics with shorter focal lengths and thinner glass lenses make the wearing of the magnification apparatus convenient and tolerable for the entire day.

Illumination

The development of diode light sources that are both lighter and consume less energy have made loupes-based illumination possible in the dental practice. The significantly decreased heat production of diode light bulbs is also more comfortable for the dentist’s forehead.

Isolation

The convenient combination of devices to isolate, illuminate, and evacuate the oral cavity into a single unit frees up valuable operative space inside the oral cavity and makes four-handed operation far more productive and two-handed treatment possible.

Air Abrasion

With respect to cavity preparation, innovations involve the use of water with the air abrasive stream, which reduces the dust that would otherwise spread around the mouth and the operatory (Figure 26-25). The traditional handpiece methods used by dentists to prepare teeth for restoration, combined with their associated sounds and sensations, can have a tremendous impact on the image of the practice, its marketing potential, and treatment acceptance by patients. Most patients dislike the noise and the vibration of the drill during the cavity preparation, often commenting on the need for alternative treatment options. Drill-less techniques have been used in dentistry for more than half a century. In the last two decades, novel abrasion technologies and improved adhesive restorative materials have made these options practical and effective.

FIGURE 26-25 The use of water with the air abrasive provider (A) helps to reduce the dust that can otherwise spread around the mouth (B) and the operatory (C).

The operating principle of this technology is based on translating the velocity of the alumina particles that are propelled through the abrasive system into abrasive energy at the surface of the tooth. Although the alumina particles have a very tiny mass, their velocity on exiting the nozzle is very high. The kinetic energy stored in this velocity is directed at the tooth surface. When the particles strike the tooth surface, the energy of the alumina micro-abrades small particles of decay, enamel and dentin, layer by layer, from the tooth. Continued air abrasion can quickly prepare the cavity, readying it for adhesive restoration. The nozzle is not supposed to touch the tooth surface, and therefore tactile feedback is severely limited. However, the dentist has good visual control and can directly observe the elimination of decay on a real-time basis. The fine focus of the stream of alumina particles exiting the nozzle permits pinpoint, ultraconservative cavity preparation.

Air abrasion is useful for direct-access occlusal, buccal, and lingual cavity preparations. It can be used to remove existing composite restorations and selectively repair composite margins. Air abrasion roughens bondable surfaces such as tooth, porcelain, metal, and composite resin, offering improved adhesion for direct and indirect, resin-cemented restorations. It can also effectively clean away permanent or temporary cements, providing a contaminant-free surface for permanent bonding. Air abrasion is used to explore pits, fissures, and small cavities to remove any remaining decay and bacteria before the application of sealants and flowables.

Ozone

Ozone technology (as discussed earlier for the HealOzone system) is a documented safe treatment modality.

With the HealOzone system, ozone is delivered inside a cup directly into the lesion being treated (Figure 26-26). If the cup loses its seal, the cup simply sucks air into itself and ceases to deliver ozone. Radical ozone ions can be quite damaging to the lungs and should not be inhaled in significant dose. The HealOzone system has been proven in many studies to be absolutely safe to use. Even when it is inadvertently misused, there is no danger of any damage occurring to the lungs of the patient, the operator, or assistants because of the safety mechanisms that have been built into the technology (Figure 26-27).

FIGURE 26-26 HealOzone delivers ozone gas directly and exclusively into the lesion.

FIGURE 26-27 HealOzone generates therapeutic doses of ozone at the sight of application.

Water Ozone Systems

Ozonated water systems are also very safe. Any ozone not delivered into the water bottle is converted into oxygen by the safety mechanisms, which is then blown into the dental operatory. The ozonated water is produced in total safety. The ozonated water can be used directly in irrigating syringes, ultrasonic scalers, cavity preparation rinses, root canal irrigation, or mouth rinsing for patients before, during, and after treatment to promote healing (Figure 26-28).

FIGURE 26-28 Ozonated water can be used in irrigating syringes (A) and or mouthrinses (B).

Innovative Elements of Fissurotomy

The SS White Fissurotomy bur (Figure 26-29) uses shapes as narrow as 0.7 mm and a cutting side as small as 2.5 mm long. The 2.5 mm relates to the average depth of the occlusal enamel. The operator can control the preparation with the Fissurotomy bur to ensure that it continues to cut enamel only, never entering the dentin. This eliminates the likelihood of patient discomfort. The conical shape of the Fissurotomy bur permits comprehensive visual access to any remaining carious material.

FIGURE 26-29 The tapered, depth-limited SS White Fissurotomy bur is used to control conservative preparation of the dentino-enamel junction (DEJ).

Treatment Planning

The dentist should not “add” minimally invasive approaches to the armamentarium. These modalities should be very much an integral part of every treatment plan. In the diagnosis of a carious lesion, every minimally invasive parameter should be included as part of the standard treatment evaluation. Minimally invasive approaches should be built into the psyche of the operator as the first determination of every treatment plan.

In the treatment process, operators typically provide pain relief first. For example, if the patient has pulpitis associated with a deep carious lesion in a particular tooth, the minimally invasive approach is to first manage the pulpitis if symptoms indicate that it may be reversible. A minimally invasive approach uses an ozone treatment as an initial step. The caries is then removed, leaving as little as 1 mm (or less) of infected dentin over the roof of the pulp chamber. Ozone treatment disinfects the tooth before the provisional or definitive restoration of the tooth, using a method that allows the pulp to heal over time. The aim is to keep the pulp vital and avoid root canal therapy. This is an integral part of the stabilization phase for pain relief.

For a patient with numerous carious lesions and clinical symptoms of pulpitis, the dentist can stabilize all of these lesions with a minimally invasive provisional approach using either gaseous or aqueous ozone or PAD as an intermediate step to definitive restoration. At the end of the stabilization phase, the dentist reviews what additional treatment, if any, may be required. This might include composite restorations, crowns, and bridges.

Treatment Considerations

Operative Considerations

Restorative Dentistry

A patient has the symptom of pain brought on by a cold stimulus that lasts only a matter of seconds and does not keep the patient awake at night. It is not a spontaneous pain, but it is always precipitated by cold. Radiographs reveal a carious lesion in close proximity to the pulp, but there is no loss of lamina dura around the root. The operative treatment plan immediately focuses on a minimally invasive approach, aiming to conserve tooth structure and to cause minimal damage to pulpal tissues. The operator proceeds to remove the caries without over-desiccating, dehydrating, or heating the dentin. The goal is to leave less than 1 mm, a very thin layer of possibly infected dentin over the roof of the pulp chamber. To verify this, a sharp probe is used with very light pressure. If the probe enters the infected dentin on the cavity floor and then can be withdrawn without any resistance, this indicates that more than 1 mm of infected dentin is present. If the probe enters the lesion with very light pressure and the cavity floor is leathery, sticky, or resistant to the withdrawal of the probe, this indicates that less than 1 mm of infected dentin is present. Holding the probe up to the radiograph to estimate the extent of the caries with respect to the location of the pulp is fraught with the usual dangers of trying to interpret three-dimensional structures using two-dimensional radiographs.

The electrical caries monitor (ECM) is used to objectively quantify the severity of the root caries index (Figure 26-30). Previously, primary root lesions were classified by color, texture, hardness, cavitation, size, and severity. The ECM can be used to determine the severity of primary carious lesions because it is a less invasive but equally accurate way to detect carious lesions when compared with tactile methods.

FIGURE 26-30 A, CarieScan PRO. B, THE CANARY SYSTEM dental caries detection system.

(A courtesy CarieScan, Ltd., Charlotte, North Carolina. B courtesy Quantum Dental Technologies, Toronto, Ontario.)

When infected dentin remains in a lesion, it is desirable to destroy the viability of the remaining bacteria. One management approach includes ozonation with water as part of the preparation phase. The ozone gas is delivered for about 60 seconds into the cavity before the restorative steps are begun. An alternative is to use a PAD system. Since dyes have less penetrating ability than gases, photoacticated disinfection is more effective when there is less infected dentin remaining.

This technique is appropriate for pit and fissure carious lesions. For all other carious lesions, the same principles apply regarding conservation of the pulpal floor of the cavity, but the periphery of the cavity should have all infected tissue removed so that the adhesive can find purchase on solid tooth structure, whether enamel or dentin. Where no infected tissue remains, a very good seal can be achieved. For crowns and bridges, the same principles apply to manage deeper caries more conservatively. Ozone is one of the most powerful antimicrobial agents used in dentistry. To be effective, all the active ingredients must be in sufficient doses and delivered via the most appropriate method. Ozone will react immediately with reductants in culture media. The recommended use is to deliver the ozone under pressure directly into a lesion by pressing the delivery tube onto the carious surface so that it is encouraged to penetrate the lesion.

Periodontal Treatment

Periodontal disease is an infective process usually associated with pathogens such as Actinobacillus actinomycetemcomitans or Prevotella intermedia. Gram-negative anaerobes have developed a selective ecologic niche that leads to the destruction of periodontal tissues. The use of pharmaceutical agents can dramatically reduce the number of these pathogens and is of great benefit in periodontal therapy. Many hygienists currently use ozonated water instead of regular water in their ultrasonic scalers. This ozonated water not only reduces the number of pathogens, but assists with healing. For periodontal surgery, ozonated water also dramatically reduces the number of pathogens and promotes healing. In managing root caries, ozone has been shown to reverse shallow noncavitated lesions when used as part of the full preventive care regimen. This includes reducing the frequency of consuming fermentable carbohydrates, increasing the use of fluoride-containing products, and improving oral hygiene. Ozone is not effective in managing deep root caries. The outer carious lesion must be removed, leaving a maximum of 1 mm of caries over the pulpal floor before ozone is applied. Common sense must be used in determining how much infected tissue can be penetrated by the ozone, and disinfection or at least a dramatic reduction of the microorganisms is needed before restoration.

Endodontic Treatment

With respect to ozone and endodontics, studies in which a sufficient dose of ozone is used clearly show that it dramatically reduces the numbers of microorganisms present in the canals. When extremely low concentrations in very low volumes of liquids or gases have been used, results have been mixed. Ozone used in sufficient doses achieves an excellent result, however. Ozonated water can be used as a routine final irrigant within the ultrasonic device. The use of ultrasonics in the root canal produces very effective acoustic streaming and ozonated water that penetrates into many portions of the intraradicular anatomy, well beyond what conventional filing methods can achieve. The end stage is ideally placed with the root canal containing ozonated water and ozone gas bubbled to further increase the concentration of ozone and reduce microorganisms inside the root canal.

Ozone works best when there is less organic debris remaining. The recommendation is to use either ozonated water or ozone gas after cleaning and shaping. Conventional irrigants can be used during the early phase. Ozonated water is then used to irrigate using ultrasonics. Ozone gas can also be bubbled into the ozonated water, and ozonated oil can be used as a medicament.

Several studies have investigated the bactericidal effect of ozone compared with sodium hypochlorite (NaOCl) as irrigation solutions in endodontic therapy. Sodium hypochlorite is not as biocompatible as aqueous ozone for human oral epithelial cells, gingival fibroblast cells, or periodontal cells.

Disinfected root canals were tested for antimicrobial presence then sealed and incubated for a week before bacterial growth was then retested. The absolute bacterial count was significantly diminished after disinfection, with equal results for NaOCl, a mixture of tetracycline an acid and a detergent (MTAD), and HealOzone. Ozone was shown to have great potential for endodontic antimicrobial use. Conventional irrigation (including with NaOCl) should be used during cleaning and shaping. Ozonated water, preferably accompanied by ozone gas, is recommended as the final irrigant with ultrasonication.

In vivo root canal contents and caries, unlike artificial biofilms, contain many molecules, including iron, that can increase the antimicrobial effectiveness of ozone and can help produce hydroxyl radicals that can further potentiate the antimicrobial effectiveness of ozone. Ozone gas has toxic effects on both human oral epithelial cells (BHY) and hepatocyte growth factor (HGF-1) cells. Aqueous ozone demonstrates no cytotoxicity and is highly biocompatible compared with other antiseptics. Ozone gas performs well compared with the established endodontic irrigants, which have equal or higher cytotoxic potentials. Ozone irrigation of the root surface of avulsed teeth has shown no negative effect on periodontal ligament cell proliferation. The ozone gas applied into the moist root canal, as delivered through the HealOzone device, dissolves in canal fluids, producing aqueous ozone, which comes into contact with tissues.

Ozonated oils were investigated histologically and histobacteriologically for their usefulness in infected root canals. These were compared with calcium hydroxide in camphorated paramonochlorophenol (CMCP) as intracanal medications and were applied either in a single visit or two visits. Analysis after 6 months found that control root canals treated in a single visit had a success rate of 46%. The success rates for CMCP and ozonated oil were 74% and 77%, respectively. Ozonated oils were also the most effective agent against bacterial species commonly associated with periradicular disease.

The transcription factor NF-κB is critical in the processes of inflammation, immune function, and apoptosis. It may also regulate periodontal and periapical inflammatory reactions and the pathogenesis of periodontal disease and apical periodontitis. Aqueous ozone exerts inhibitory effects on the NF-κB system, indicating possible anti-inflammatory and immune-modulating abilities.

Surface Finishing and Polishing

For finishing, the least invasive and the most rapid procedure is generally the best. The SS White Jazz Supreme polishing system (Figure 26-31) is a one step, one instrument polishing system that provides a highly successful clinical approach. Most polishing systems offer a series of progressively smoother polishing instruments, from coarse to medium to fine, but with the Jazz System a single instrument is used throughout the polishing process. The progressive abrasiveness depends on the pressure that the operator places on the instrument during the polishing of the tooth surface. With greater pressure, the effect is more abrasive, actually removing or smoothing the surfaces. As less pressure is applied, the bur’s action tends to buff and produce a final luster. Within seconds an acceptable anatomy can be molded, shaped, and polished to a high-gloss, high-luster surface that will last for many years.

FIGURE 26-31 Jazz Supreme polishing system.

(Courtesy SS White Burs, Inc., Lakewood, New Jersey.)

Evidence-Based Principles

Research has demonstrated that cariogenic bacteria can be killed by directly applied ozone in gas or liquid form and by visible light after they are photo-sensitized. The ozone technique involves the flooding of a dental structure with ozonated air or water. As the ozone bathes the tooth structure, ozone ions penetrate it to various depths and disrupt the cell walls of any bacteria that are encountered, destroying them. The PADS technique involves applying a photoactive solution that is absorbed selectively by cariogenic bacteria to the operative surfaces. This sensitizes them to the application of visible illumination, which causes cytotoxic bacterial reactions that result in selective destruction of the target microorganism.

Controversies

Cochrane standards have been applied to the assessment of ozone only as an alternative rather than in addition to current methods for managing and treating dental caries. Ozone should not be applied in isolation; it is designed to be used in conjunction with current caries management methods. Because ozone is much easier, cheaper, and faster than existing treatments, it should be assessed on its overall effectiveness. Instead of being compared with conventional drilling and filling approaches, it should be compared with similar antimicrobial and oxidant treatments for caries.

Near-Future Developments

An interesting area of future development is the use of adhesive resin technologies that can infiltrate infected dentin. If these can be managed with ozone or PAD first, infiltration resins will contribute further to truly minimally invasive dentistry.

Diode Lasers: The Science in Brief

The word laser is derived from the acronym for light amplification by stimulated emission of radiation. Lasers are commonly named for the substance that is stimulated to produce the coherent light beam. In the diode laser, this substance is a semiconductor (a class of materials that are the foundation for modern electronic devices, including computers, telephones, and radios). This innovative technology has produced a laser that is compact and far lower in cost than earlier versions. Much of the research has focused on the 810-nm diode laser. Energy of this wavelength is ideally suited for soft tissue procedures because it is highly absorbed by hemoglobin and melanin. This gives the diode laser the ability to precisely cut, coagulate, ablate, or vaporize the target soft tissue.¹

Treatment with the 810-nm diode laser (Figure 26-32, Picasso diode laser, AMD Lasers, Indianapolis, Indiana) has been shown to have a significant long-term bactericidal effect in periodontal pockets. A. actinomycetemcomitans, an invasive pathogen associated with the development of periodontal disease and generally quite difficult to eliminate, responds well to laser treatment.^2,³ Scaling and root planing outcomes are enhanced when diode laser therapy is added to the dental armamentarium. The patient is typically more comfortable during and after treatment, and gingival healing is faster and more stable.^4,⁵

FIGURE 26-32 The Picasso diode laser.

(Courtesy AMD Lasers, Indianapolis, Indiana.)

Diode Laser: Ease of Use

Early adopter dentists thrive on new technologies. They enjoy the challenges that come with being the first to use a product. Most dentists, however, are not early adopters. Over the past two decades, lasers have intimidated mainstream dentists with their large footprint, lack of portability, high maintenance profile, confusion of operating tips, and complex procedural settings. Common questions have included the following: When do I use which tip? What setting works for which procedure? Why do I need a laser when I have been managing well without one?

Enter the diode laser. It is compact. It can easily be moved from one treatment room to another. It is self-contained and does not have to be hooked up to water or air lines. It has one simple fiberoptic cable, which can function as a reusable operating tip. The units come with several presets, although after a very short time the operator becomes so comfortable that they are rarely needed. The power and pulse settings are quickly adjusted to suit the particular patient and procedure.

One of the authors is a dentist who does not thrive on the challenge of brand new high-tech, high-stress technology, having tried many lasers in the past that were said to be user friendly but were found to be anything but. The 810-nm diode laser provided a totally different experience; after a brief in-office demonstration, the laser handpiece felt comfortable enough for the author to perform some simple clinical procedures. Further online training and lecture courses enhanced both clinical comfort level and competency.

Diode Laser: Affordability

Laser technology has always come with a high price tag. Manufacturing costs are high, and cutting edge technology commands steep pricing. Diode lasers are less expensive to produce. Breakthrough pricing for this technology has now reached under $5000. At this level the diode laser becomes eminently affordable for the average practicing dentist.

Diode Laser: Why do I need this technology?

The 810-nm diode laser is specifically a soft tissue laser. This wavelength is ideally suited for soft tissue procedures because hemoglobin and melanin, both prevalent in dental soft tissues, are excellent absorbers. This provides the diode laser with broad clinical utility: it cuts precisely, coagulates, ablates, or vaporizes the target tissue with less trauma, improved postoperative healing, and faster recovery times.⁶^–⁸ Given the incredible ease of use and its versatility in treating soft tissue, the diode laser becomes the “soft tissue handpiece” in the dentist’s armamentarium. The dentist can use the diode laser soft tissue handpiece to remove, refine, and adjust soft tissues in the same way that the traditional dental handpiece is used on enamel and dentin. This extends the scope of practice of the general dentist to include many soft tissue procedures.

The procedures discussed in the following sections are easy entry points for the new laser user.

Gingivectomy, Hemostasis, and Gingival Troughing for Impressions

The diode laser (Picasso) makes restorative dentistry “a breeze.” Any gingival tissue that covers a tooth during preparation can be easily removed, as hemostasis is simultaneously achieved (Figure 26-33). The restoration is no longer compromised because of poor gingival conditions. There is no more battling with unruly soft tissue and blood. Excess gingival tissue can be readily managed (Figure 26-34) for improved restorative access for class V preparation (ezLase, Biolase Technology, Irvine, California).

FIGURE 26-33 Hemostasis is simultaneously achieved with the laser when gingival tissue covering a tooth (A) is removed during preparation (B to D). E, One week post-op.

(Courtesy Dr Phil Hudson.)

FIGURE 26-34 Excess gingival tissue can be readily managed with the laser (A) for improved restorative access to class V preparations (B).

(Courtesy Biolase Technology, Irvine, California.)

Gingival troughing before an impression is taken (see Figures 26-33, E and 26-34, A [Picasso]) ensures an accurate impression (particularly at the all-important margins) and an improved restorative outcome. Packing cord is no longer necessary.

Diode lasers make restorative dentistry less stressful, more predictable and more enjoyable for the dental team and the patient.