Allergic reactions are relatively rare in the dental office. Nevertheless, it is important for the dentist to be able to identify allergic reactions and to act accordingly. The type of allergic reactions may be immediate (Type I), for instance related to latex, penicillin, or food components, or delayed (Type IV), for instance related to amalgam, gold, palladium, composite, or nickel. In most cases, the clinical features described below are sufficient for the correct diagnosis.
Anaphylactic reactions can potentially become very severe, and even lethal, if not treated correctly and in time. Several of the medications and materials regularly used by dentists may trigger anaphylactic reactions or shocks in predisposed patients. Deaths due to anaphylactic shock in the dentist’s chair has repeatedly been described in the literature. It is therefore essential for dentists to recognize the symptoms of anaphylaxis and to be familiar with the treatment algorithm. This chapter describes the epidemiology, clinical presentation and pathophysiology of anaphylaxis. An updated overview of the recently proposed treatment algorithm, including a detailed guide to emergency airway management, is also presented. Finally, a case of severe anaphylactic shock in a dental setting is described and discussed.
Halitosis – causes and treatment
Halitosis, also known as bad breath or oral malodour, is a term used to describe noticeably unpleasant odour coming from the mouth or respiratory system. This condition is reported to affect about 25 % of the population on a daily basis. Morning bad breath, experienced by many upon waking in the morning, most likely due to local oral conditions, is usually only a temporary problem that can be easily prevented or treated. However, some cases of halitosis, especially those associated with extra-oral causes, can be more chronic and can adversely affect a person’s social and work situation. Dental health workers regularly meet patients who either complain of bad breath or have halitosis without being aware of the situation. Knowledge of the usual causes of halitosis and treatment methods for oral malodour should therefore be mandatory. In this short overview, the most common physiological and pathological oral causes of halitosis will be described, as simple preventiv and treatment strategies well as possible extra-oral causes. The overview will present simple, preventive, and treatment strategies with a focus on the oral cavity.
Traditionally, amalgam has been used for Class II restorations in primary teeth, but the use of amalgam has decreased in Scandinavia during the latest few decades, and now, amalgam has been banned in Norway and Sweden. Glass ionomer (GIC) adheres to tooth substance and has been a popular alternative to amalgam, but the traditional GIC products do not give as high longevity as amalgam in Class II restorations. As the traditional GIC has been improved (high viscous GIC), and GIC has been combined with resins (resin-modified GIC and polyacrylic acid modified composite resin), the longevity of restorations has improved. GIC containing materials are technique sensitive. The placing of materials containing resin should be done in steps when the thickness of the restoration exceeds 2 mm. Composite can be used as the top layer (“sandwich”). Uncured resin which may penetrate into the pulp and into the oral environment represents a potential risk for adverse effects although no scientific evidence exists so far. GIC contains fluoride which is released from the restoration. The clinical importance of this release has been disputed, but it is likely that this fluoride may have some caries preventive effect (secondary caries). Stainless steel crowns are recommended for restoring extensive carious lesions in primary molars.
Resin composite restorations in increments or in bulk?
So-called bulk-fill resin composites have been introduced in order to fill deep cavities in one or two increments, thus simplifying an otherwise elaborate, incremental restorative procedure. The prerequisite for the use of bulk-fill composites is their claimed depth of polymerization of 4 mm, obtained mainly through modification of the photoinitiator system, thus allowing for placement of layers of 4 mm compared to the conventional 2 mm. This chapter describes and discusses the composition, the physical properties, and the clinical use of bulk-fill resin composites. Bulk-fill resin composites are available in low-viscosity (or flowable) and high-viscosity versions. Because of the lower filler volume needed to reduce the viscosity, low-viscosity materials have decreased strength and must therefore be covered by an occlusal layer of conventional resin composite. Such a covering layer also alleviates any aesthetic issue caused by the higher transparency or the limited number of shades of some low-viscosity materials. Studies of depth of polymerization and stress formation are still scarce, and results are often contradictory, hindering the possibility of drawing any clear-cut conclusions. Additional in vitro data and clinical studies are warranted, and in the meantime, dentists are advised to apply a sound, critical approach and stay well within the indications.
The main problem with ceramics as biomaterials is that they are brittle. One focus of research and development has been on improving the materials’ fracture strength and thereby increasing the clinical success rates for dental, all-ceramic restorations. The most advanced dental ceramics should, according to in vitro testing, be able to withstand human mastication forces. Still, fractures occur more often than we like. Comparison of clinical observations and in vitro trials seeks to explain how and why these fractures occur. Fractographic analysis is a methodology used to investigate unexpected failures. Fractures in a brittle material leave tell-tale features on the fracture surfaces that can reveal both the origin of the fracture and the direction of crack propagation through the structure. Until very recently, fractography has only been applied to dental ceramics to a very limited extent. The method has revealed that fractures which occur in vivo usually start in the cervical margin, while fractures that have been produced in vitro usually start occlusally. This explains the discrepancy between fracture load in vitro and clinical fracture rates. Through simulation in vitro of clinical fracture behavior, we gain an understanding that suggests different strategies for tooth preparation and crown design.
“Nano” is a term being increasingly used in marketing of dental products. A nanometer (nm) is one billionth of a meter (10-9 m), about 100.000 times smaller than the width of a human hair. Nanotechnology is the application of processes on the nanoscale to create e.g. materials with tailor-made properties.
Nanoparticles are nano-objects with at least one dimension between 1 and 100 nanometers. Such particles behave differently than larger ones, partly due to the high surface/volume ratio. Today, the main application of nanoparticles in dentistry is to be passive fillers in restorative materials, represented by the nanohybrids and nanocomposites. Still, there is lack of long-term clinical data of “nanorestoratives”. It appears that they represent an evolution rather than a quantum leap.
Some materials include nanostructures with active functions; one example is “nanosilver” used as an antibacterial agent. It is likely that the application of active and “intelligent” nanostructures will increase, e.g. self-assembling mineral structures to obtain remineralisation.
Nanoparticles may cross biological barriers, which could represent a potential biological risk, but this property could also be beneficial, for example for targeted drug delivery.
Today’s use of nanotechnology in dentistry is simple, but there is a formidable potential in diagnostics, prevention, and restoration of damaged dental tissue.
New surface modifications of oral implants
New implant surfaces continue to attract interest from scientists, manufacturers, as well as from the implant market. New surface modifications are commonly related to variations in nanotopography, chemistry, and/or physical alterations. However, if one factor is altered, inevitably others may change as well – a nanocoat, for example, alters topography, but most likely, chemistry and possibly hydrophilicity will be altered as well. Thus, it is very difficult to know which individual factor will influence the biological response to the greatest extent.
Most surface modifications are still aimed at improving the implant incorporation into the bone, but some articles have been published on surface variations to improve soft tissue adherence and to establish antibacterial coats. Several studies report an improved healing capacity in in vivo experiments, but more studies are required to clarify the clinical relevance of such innovations.
The pricing of fixed prosthodontics is similar within the Nordic countries, due to tradition in the clinical and laboratory sectors. Patients are, however, encouraged to seek internet price comparisons by e.g. the Swedish National Insurance System and the Danish Dental Association. At the same time, some reluctance against international dental shopping is detected. However, import of laboratory products from East Asia has grown considerably due to economy. Apart from these general aspects, examples are given of cheap and rational clinical treatments like: acceptance of the shortened dental arch concept giving the greatest economic gain, fibre- reinforced composite bridges that are quick, cheap, and reasonably effective, two-unit bridges that are low price alternatives to removable partial dentures as well as conventionally extended bridges, resin bonded bridges that are low invasive, esthetic and cost-effective. Rationalization is exemplified by one-cast post-crowns, posts and cores and outer crown on the same master model, crowns in metal, immediate pontics, and alternatives to precious metal. It is, however, also discussed that a wider price range between simple cases and complex risk patients could give a more correct pricing and cheaper alternatives for the majority of patients.
Oral Health related Quality of Life
Oral health related quality of life, as part of the general concept quality of life, is an expression of a person’s experience of and coping with life, but limited to aspects of oral health. The concept means different things to different people and is thus difficult to define, measure and interpret unambiguously, and the measurements are only meaningful at a group level. Nevertheless, relevant literature allows some general conclusions to be drawn: Oral health related quality of life is reduced as the number of remaining teeth decreases; particularly when tooth loss occurs in the anterior region of the mouth. Oral health related quality of life may be improved when lost teeth are restored with a fixed partial denture, but only if it had been adversely affected prior to the rehabilitation. However, this improvement appears to wear off in time. For the completely edentulous, a long term significant improvement is recorded if their conventional mandibular denture is turned into an overdenture retained by two implants. Based on this knowledge, prosthetic rehabilitation should start with a structured interview where the patient’s individual oral health related quality of life is revealed, so that an optimal patient treatment may be administered.
Safe use of dental laser
Laser is employed for a variety of tooth and oral treatments. Numbers from a national registry indicate that its use has doubled during the latest five years. This increase has occurred despite, in many instances, the lack of evidence of superior treatment outcome relative to conventional or other new treatments. It is anticipated that more clinical, high-quality investigations will reveal which laser treatments are scientifically sound. This chapter includes a brief review of laser technology, technical data, tissue effects and interactions and factors influencing penetration depth. Literature examples compare laser and conventional treatment. These conclude that the advantage of laser treatment seem to be less post-operative pain, and that the instrument is preferred by patients. The topic of laser safety is dealt with in detail because many dental lasers have the potential to cause injury. As in general phototherapy, the medical use of laser must be optimized and justified. Laser operators must adhere to safety requirements and regulations. Injuries on vulnerable organs, such as the eye, skin, pulp, and respiratory tract are described. An overview is given of the health professions which are entitled to use the strongest lasers in medical/dental treatments in the Nordic countries.