Article
Every day millions of operative dental procedures are carried out by clinicians worldwide. The majority of these involve the replacement of existing restorations prior to tooth preparation for new direct or indirect restorations. Unfortunately, when anterior and posterior tooth preparations involve proximal surfaces there is a high risk of accidental damage to previously healthy adjacent structures which may have negative consequences for oral health in the short- or long-term.
In many parts of the world, minimally invasive (MI) techniques are now at the forefront of contemporary restorative dentistry and the prevention of iatrogenic damage to hard and soft tissues is one of the fundamental MI principles.
Prevalence
It is well documented that the prevalence of iatrogenic damage is extremely high. Tooth preparation of Class II cavities almost always results in some level of unnecessary damage to adjacent hard tissues1 and indirect preparations carry a 75% risk of iatrogenic damage to one or both adjacent teeth.2
A recent study demonstrated that, when using high-speed rotary instruments, experienced dentists damage 75% of adjacent surfaces with a range of severity, rising to 95% for inexperienced dentists, with extensive damage recorded in over 20% of cases.3
Aetiology
Iatrogenic damage has been described as being ‘virtually impossible’ to avoid owing to the environment in which operative procedures are carried out.4 The main aetiological factors predisposing to iatrogenic damage are:
Consequences
Iatrogenic damage often results in negative consequences, eg even slight bur contact with adjacent enamel damages the outer acid-resistant aprismatic layer, exposing deeper layers that are more susceptible to demineralization. Some of the complications that may result from iatrogenic damage are:
A clinical example is presented in Figure 1.
Repair of iatrogenic damage
Hard tissue defects are irreversible and may be challenging to repair due to limited access for vision and instruments and difficulties in moisture control and adaptation of thin layers of restorative material. While slight periodontal trauma may be expected to repair naturally, damage to the connective tissue attachment (biological width violation) routinely results in persistent inflammation.
Prevention of iatrogenic damage
A number of techniques are available to reduce the risk of iatrogenic damage and, if optimized, have the potential to eliminate it completely.
Protective wedges
While restorative matrices may be used to protect teeth, they are very thin and can impede visual access. Innovative protective wedges (Figure 2), inserted before the risk of iatrogenesis arises, are effective in protecting adjacent tissues during all stages of cavity preparation and confer the following additional advantages:
Optimizing visual access
Visual access may be improved by a selection of optical aids which are available in a range of standardized magnifications and recent adjustable versions (Figure 3).
Loupes with approximately 2.5X magnification may be considered optimal for routine operative procedures with magnifications increasing beyond 20X for operating microscopes. Powerful, integrated, LED lights may also be used to provide outstanding illumination of the operative field.
Further visual enhancement may be achieved by employing techniques that control moisture and retract soft tissues, including:
Tooth preparation equipment and techniques
Careful clinical technique is of prime importance in avoiding iatrogenesis. The risk should be assessed pre-operatively and sufficient time allocated to the most difficult aspects of operative procedures. Other safe-preparation techniques that may be used in combination are:
Summary
Iatrogenic damage is an exceptionally common complication of operative procedures and may result in a range of negative effects. A variety of methods are available for minimizing accidental injuries and, if carefully employed, may eliminate the risk completely.