Since its start, the originators of the ART approach noticed that the technique had a potential to cause less discomfort to the patient and to be less invasive to the dental tissues than the conventional approach. The patient's acceptance of ART was verified by Mickenautsch and Rudolph [16
], who observed that both children and adults receiving ART restorations responded very positively to the treatment. They ascribed this reaction to ART's “patient friendly” properties. Dentists also seemed to approve the “new” approach. Among the main reasons given were those related to the patient's comfort: the reduced use of local anaesthetic and absence of the noisy drill and suction [17
]. Dental students' perceptions, after receiving a special training on ART and applying it to their patients, were in agreement with those of the dentists. The fifth-year students reported perceptions related to dental anxiety, minimal loss of tooth tissues and to the fact that they could clearly see patients' expressions changing from fearful to more relaxed as the most relevant aspects of the ART approach. These experiences contributed to an increase in their confidence as operators [18
However, analysis of clinical trials that have compared patients' comfort during ART and the conventional approach using different restorative materials revealed inconclusive results. Basically, these studies investigated two aspects related to the patients' comfort: dental pain and dental anxiety. A summary of these studies' outcomes is presented in Table . All studies, except the one from Mickenautsch et al. [24
] that also included adults, were performed on children. From the seven studies retrieved, three showed no difference between the two types of treatment in levels of anxiety or pain, while the other four suggested that ART was found to be less painful and caused less dental anxiety. What could be the explanation for these controversial results? Besides methodological aspects, apparently, the outcomes were also influenced by the operators' level of specialisation and/or skills in handling anxious children. The studies from Topaloglu et al. [23
] and de Menezes Abreu et al. [21
], in which no difference in levels of dental anxiety and dental pain were observed, were performed by paediatric dentists. In the studies that favoured ART [19
], all operators, but the one from de Menezes Abreu et al. [21
], were non-paediatric dentists (general practitioners, dental therapists or dental students). However, the latter study had included children younger than 6 years, and all those given the conventional treatment received local anaesthesia and the restorations were performed under rubber dam isolation. It is not unrealistic to argue that age and the use of the needle and that of rubber dam might have influenced children's perception of pain.
Overview of studies having assessed dental anxiety and dental pain between the ART and the traditional treatment approach
In light of all these aspects, it can be hypothesised that the behaviour management provided by a paediatric dentist may overcome much of the discomfort that a child can feel independently of the restorative treatment approach. On the other hand, it can be argued that ART could be a facilitator for good behaviour management when the dentist is not so skillful in dealing with children. For those very young, ART is the best treatment option, whether the operator is a specialist or not [21
], as age is associated with dental behaviour management problems; the younger the child the more behaviour problems are expected [26
]. With regard to adult patients, there is only one study in which the impact of ART on patients' comfort was tested [24
]. It indicates that ART caused less anxiety than the traditional approach using rotary instruments.
Another atraumatic aspect of the ART approach that should be also taken into account refers to its potential to be less invasive to the dental tissues. Following the concept of minimal intervention dentistry (MID), only decomposed dentine needs to be removed in order to stop carious lesion progression. This then leads to the question as to which method removes decomposed dentine best. In vitro studies have shown that, among the common caries excavation methods tested, hand excavation was the best method, in terms of combined efficiency and effectiveness, for cleaning of occlusal cavities in primary [27
] and permanent teeth [28
]. It is obvious that hand instruments, unlike rotary instruments, have a limited ability to remove sound tooth tissues. It is therefore no surprise that single-surface cavities prepared by hand instruments as part of the ART approach were significantly smaller than those prepared through rotary instrumentation [29
The ART potential as an atraumatic management approach for cavitated dentine carious lesions for both children and adults has already been discussed [30
]. However, well-designed trials are still needed to confirm this conclusion as well as testing the influence of the type of operator on patients' behaviour.