Atraumatic Restorative Treatment: More than a Minimally Invasive Approach?

Abstract

Minimally invasive (MI) caries management has largely evolved over the years to include approaches that not only aimed to preserve as much tooth structure as possible but also to embrace prevention and risk management strategies. The atraumatic restorative treatment (ART) is a minimally invasive approach that was initially established to address the issue of increasing number of salvable teeth that kept being extracted in remote parts of the world where there was a limited access to the necessary equipment to enable preserving teeth in the primary and permanent dentitions. Managing carious lesions following ART is not as demanding as that in the conventional restorative methods, however, there are certain factors known to contribute to the failure of atraumatic restorative treatment that need to be considered to ensure success. However, and despite the advantages associated with using ART there seems to be a lack of awareness among dental practitioners regarding adopting this approach that can largely affect effective practice. Therefore, there is a need to spread the awareness and further educate practitioners particularly in this Covid-19 era where the virus and its variants have impacted the provision of routine dental treatment and will continue to do so for the foreseeable future.

1. Introduction

Dental caries is a widespread multifactorial oral disease where aetiological factors such as dietary carbohydrates, acidogenic microbial flora, time in addition to other specific host factors can greatly contribute to its development and progression [1, 2]. If left untreated, the complications of dental caries can affect oral as well as general health; both can eventually have a negative impact on human’s quality of life [1]. The management of caries has traditionally involved drilling and the complete removal of all carious tissue which is then replaced by a restorative material [3]. This ‘drill and fill’ approach is not risk free though and often associated with either iatrogenic or caries-induced pulpal exposure, the incidence of which is greatly increased in deciduous and young adult teeth [3]. Other risks include the inevitable removal of sound tooth structure in the process of eliminating the carious lesion in addition to those risks related to the prolonged procedure times and the need for the local anaesthetic, that both can trigger dental anxiety [4]. Moreover, previous research into ‘no drill’ management techniques have stated that the ‘drill & fill’ approach is not required in many cases of dental caries as caries develops slowly and it could take the disease an average of 4–8 years to progress from enamel to dentine providing clinicians with sufficient time to detect and treat the lesion before it is cavitated and therefore, reducing the need for restorative treatment [5]. Therefore, there is a need for further emphasis on establishing more strategies such as minimal intervention approaches to effectively manage dental caries by intercepting the disease at its early stages while preventing the formation of new lesions [6, 7].

Minimal intervention (MI) is a branch of dentistry that aims at maintaining as much healthy tooth structure as possible through focusing on managing caries using a therapeutic or a biological approach rather than the traditional G.V Black operative guiding principles [8]. Minimally intervention dentistry (MID) is therefore based on four core principles (1) Early caries detection and assessment of potential risk factors. (2) Control of risk factors to either eliminate or minimise caries through the analysis of diet and lifestyle habits. (3) Arrest or remineralise early lesions using topical agents containing elements such as Fluorides and Calcium. (4) Remove caries conservatively, when intervention is required, to preserve as much sound tooth structure and maintain lifetime function [9].

MID has gained dental practitioners’ interest worldwide, however, in areas such as developing countries where limited access to dental resources existed, there was a need to find alternative MI approaches to enable providing dental care to patients who are deemed suitable to receive minimally invasive treatments; hence, Atraumatic Restorative Treatment (ART) was developed [10, 11].

2. Atraumatic Restorative Treatment (ART)

ART is defined as the removal of demineralised soft dentine with the aid of hand instruments only followed by the replacement of the excavated tissues and sealing the adjacent pits and fissures using bonding or adhesive restorative materials [10, 11]. Although ART is an alternative approach to MID, it still encompasses the same MID core principles [9] and it can be used to conservatively manage caries in both primary and permanent dentitions particularly for patients who are considered suitable to have the procedure but are dentally anxious or challenging to handle [12, 13]. Other advantages to adopting ART include the removal of soft demineralised dentine; pits and fissures as well as the cavity get sealed with the restorative material; little or no pain is usually associated therefore, minimising the need for the local anaesthetic, greatly reduced patient stress as no vibrations from rotary instruments, infection control measures are simpler to follow, in addition to the relative low costs when compared to the conventional treatment modalities [11, 14].

3. Indications and contraindications of ART

As mentioned earlier, ART is indicated where there is a limited or no access to routine dental and preventive care, additionally it can be used as a community measure to control caries in schools or in care homes and for people with disability who are known to feel fear for dentists and dental treatments [15, 16, 17, 18]. This approach is however contraindicated when there are signs of irreversible pulpitis, pulp exposure, presence of abscess, a sinus or a periapical/interradicular pathology or simply when lesions are inaccessible to hand instruments [18].

4. ART patient satisfaction and popularity among dental practitioners

According to previous studies, high satisfaction rates were received when 68% and 85% of the respective 5- to 18-year-old patients reported absence of pain during caries excavation and during filling [19]. Further research in patient perception of ART demonstrated that only 6 (6.6%) and 26 (29.2%) of the ninety 14- to 15-year-old students who accepted to be treated using the ART approach did experience pain and discomfort [20]. More supporting data were received, particularly from patients who previously received conventional restorative treatment that, of the 262 participated in the study, 99% expressed their satisfaction with ART restorations, 96.6% were willing to undergo this procedure in future, and 94.9% were happy to recommend this treatment approach to close relatives [21].

Existing research reported that the ART approach has already been used by most dental practitioners whenever they temporise teeth [22]. However, a later study that investigated the awareness of the ART method among 600 UK GDPs has concluded that only 42% indicated their awareness of the effectiveness of ART in the treatment of caries and that less than 10% of the participated GDPs used the ‘true’ ART technique [23].

5. Caries removal in ART

Dentine caries consists of two layers; the closer to the enamel outer infected (contaminated) and the deeper inner affected (non-contaminated) dentine [24]. The former layer is formed of dead, very soft tissue and therefore easy to excavate using hand instruments while the latter layer has a firmer consistency as it contains higher mineral content, sensitive as its formed by vital dentine, contains minimal or no bacteria and hence can be left behind to remineralise [25]. A common challenge encountered by dentists is how much contaminated dentine to be removed or retained in order to allow for pulp healing? The clinical differentiation between the two dentine layers is subjective, however, there has been a general consensus towards leaving some contaminated dentine in deep carious lesions as long as it is well-sealed within the cavity [26, 27]. This paradigm shift in understanding the carious process constitutes the basis of ART by changing the cariogenic environment through isolating caries bacteria from the biofilm of the oral cavity would result in enhancing the dentine-pulp complex defence mechanisms leading to slowing or arresting the deep carious lesions [28].

In an attempt to facilitate the decision of what strategy to adopt, ART Vs conventional, when removing carious tissue in asymptomatic teeth having noncleanable carious lesions with vital pulp and no signs of irreversible pulpitis, previous research reported that carious lesion depth (as demonstrated during radiographic assessment if justified) and the dentition type (primary vs permanent) can be taken as a guide in the decision-making process [29]. In the same study, the authors stated that the ART approach can be used to treat:

1. Primary and permanent teeth with shallow to moderate carious lesion depth that has not reached 1/3 or 1/4 of the dentine and having no risk of pulpal exposure.

2. Permanent teeth having deep carious lesions that has reached 1/3 or 1/4 of the dentine and showing risks of pulpal exposure.

Furthermore, in ART, once caries is excavated to firm in shallow to moderate cavities and to soft dentine in deep lesions, the excavated tissue is replaced as well as the adjacent pits and fissures are sealed using high viscosity glass ionomer cement or with a resin sealant [25] as will be described in the following sections.

6. Materials used in ART

Generally speaking, the minimally invasive concept is mainly about preserving as much tooth structure as possible indicating that the resultant cavity preparation in most situations does not conform to the ideal properties of including mechanical features for retention purpose. However, the advances in adhesive restorative materials enabled promoting MID and other approaches that fall under the MI umbrella namely ART.

The ART materials of choice are resin composites or glass ionomer cements (GICs), however, owing to its physical and chemical properties, GIC has mostly been indicated for use as ART sealant [12, 30]. Some of those properties are adhesion to enamel and dentine [31], anticariogenic effect due to fluoride release [32, 33], biocompatibility [34], coefficient of thermal expansion that is similar to enamel and dentine [35] in addition to the ease of manipulation and its relatively low cost. Several studies, however, have indicated that the viscosity of GIC is an equally important factor in the success of atraumatic restorative treatments with a wider agreement that high viscosity GIC (HVGIC) such as GC Fuji IX™ and 3M ESPE Ketac Molar™ are more durable than the low- or medium-viscosity namely GC Fuji lining™ LC and Ionofil Plus VOCO, respectively [36, 37, 38, 39, 40]. The reduced viscosity formulae were used in the early years following the introduction of ART technique; however, studies have reported that the material in both consistencies exhibited low wear resistance and lack of compressive strength in high stress-bearing areas [41, 42]. This has led manufacturers to develop an advanced GIC formula; the so-called HVGIC which characterised by having a high powder-to-liquid ratio and improved mechanical properties such as wear performance, compressive strength, and marginal adaptability rendering it more appropriate for use with ART [43, 44, 45]. Resin modified GIC (RMGIC) has also shown a promising performance than the conventional GIC as an ART sealant demonstrating highly acceptable retention rates in occlusal and approximal cavities which indicated that it can be considered as an alternative restorative material comparable to HVGIC in ART [46, 47, 48]. RMGIC is a two-component system: the conventional GIC acid-base in the form of Polyalkenoic acid and fluoro-aluminosilicate glass in addition to the resin and the light-initiating compound [49]. Similar to that of the conventional GIC, the resin-modified formula provides the cariostatic effect while possessing strength and better aesthetics from the resin content [49]. Furthermore, RMGIC has superior mechanical and physical properties to those of the conventional GIC enabling the material to provide increased fracture resistance in high occlusal load areas [50]. On the other hand, the presence of resin among the constituents indicates the potential risk of polymerisation shrinkage that could affect the material adaptation around the cavity walls and margins [51]. Other RMGIC disadvantages include marginal discolouration overtime [52], the increased cost when compared to the conventional GIC in addition to the inability to use RMGIC as an ART sealant when there are no light-cure equipment available [51].

Composite resin (CR) is another alternative material that can be used as an ART sealant restoration as previous research reported that CR used in ART approach showed good results similar to those from HVGIC [53]. The development in the adhesive material industry provided the new CR materials with much improved physical and mechanical properties such as flexural, tensile, and compressive strengths making them more suitable in areas inside the mouth which are under high occlusal stresses [54]. However, the inherent polymerisation shrinkage (PS) property and material handling are issues that can affect their longevity long term. Previous reports have shown that the volumetric shrinkage that results from the PS caused polymerisation stresses to pull restoration and the cavity walls towards the centre of the cavity which could eventually lead to poor internal and marginal adaptation resulting in microleakage and postoperative sensitivity [55, 56]. Furthermore, composite resin properties were enhanced to bond to caries-free dentine indicating that, when used as part of ART in deep cavities, the material will have lower bond strength to the soft dentine [29]. Therefore, when performing ART special care should be taken while excavating caries in moderate to deep lesions in the permanent dentition to leave behind soft dentine only on the pulpal floor whereas the cavity walls should be cleaned to ensure good marginal seal [29]. Additionally, it has also been recommended that placing CR in increments, rather than bulk fill, would help minimising the effect of PS [51]. Others, on the other hand, have found that using RMGIC as a liner in deep cavities under CR further reduced the effect of PS as RMGIC’s lower modulus of elasticity enables it to absorb PS and occlusal loading stresses [50]. Despite all that, the multilayer placement and achieving high levels of moisture control when using composite resins make the use of HVGIC as an ART sealant restoration is the preferred option.

Compomers; resin reinforced glass ionomers have also been used as ART restorations as, similar to GIC, their cariostatic property due to the fluoride release provides an advantage to use them over composites particularly in primary teeth and high caries risk patients [57]. When their survival rates were tested against those of HVGIC, the two showed comparable results and both materials were suitable as occlusal and approximal restorations for ART in primary molars [58, 59]. However, due to their resin content compomers undergo some PS which could result in marginal leakage [60] and therefore, HVGIC remains the material of choice as an ART sealant restoration.

7. A step-by-step guide to ART sealants and restorations

The atraumatic restorative treatment approach is of two components: the ART sealants and ART restorations where in the former the pits and fissures get sealed using HVGIC while in the latter the excavated carious dentine is replaced with a sealant restoration [61]. It should be borne in mind though that with ART restorations, not only the cavity created as a result of carious dentine excavation gets filled with a sealant restoration, but the adjacent pits and fissure should be included in the sealing process [62, 63]. Pits and fissures of the posterior teeth are more prone to develop caries and sealing them provides a smooth protective layer that prevents food accumulation and bacterial growth in addition to facilitating maintaining those areas clean [64, 65].

Although it might sound simple and straightforward to perform, ART success is dependent on strictly following a set of steps and a prevention plan to ensure achieving the desired outcomes. The WHO Oral Health Programme has reported that ART is an important element of a health care package that includes promotion of oral health and prevention care [66]. Infection control measures should always be applied before, during and after the procedure. The next step would be to assess the carious lesion to ensure suitability for the ART approach; it has been reported that asymptomatic teeth with no signs of irreversible pulpits but having lesions extending into dentine where cavities are accessible to hand instruments are good candidates for ART [67]. Also, the ART approach can be used to restore one-and multi-surface cavities in the anterior as well as posterior teeth where the stages involved in cavity preparation and restoration are similar [67]. Achieving moisture control through the use of rubber dam, particularly while placing sealant restoration has always been recommended whenever applicable. However, as the material mostly used for ART is GIC the use of rubber dam is not considered critical to the success of the procedure as studies have found no difference in the survival rates of ART restorations with or without its use [68] and therefore, the use of cotton wool rolls would be sufficient as long as they keep the surrounding area dry.

Since its initiation back in mid-80s, ART approach did not rely on using high technology equipment, but it rather simplified caries treatment to dental care providers in the developing countries to provide better oral health care to patients. One example is the no need for dental chairs as this approach was meant to enable dental practitioners to use ART in different field conditions such schools [69]. Nonetheless, good working conditions in terms of operator, assistant if available, and patient positions must be ensured for convenience and better treatment outcomes.

8. Armamentarium

One of the fundamental aspects of ART is the use of basic dental instruments and materials that can be found and easily handled in any non-high technology or even outside dental settings such as schools or nursing homes [63]. These include the following:

8.1 Basic dental instruments

• Mouth mirror

• Explorer/probe

• Spoon excavators (preferably different sizes)

• Dental Hatchet

• Tweezers

• Applier/carver

• Mixing pad and a spatula

8.2 Materials

• Glass Ionomer Cement (GIC)—High viscosity

• Dentine conditioning

• Cotton wool rolls and pellets

• Petroleum jelly/vaseline

• Mylar/plastic matrix strips for multi-surface restorations

• Wedges

9. Positioning and posture during ART procedure

Patient, dentist, and the assistant positions play an important role in facilitating the delivery of ART stages and could indirectly contribute to enhancing the success of the treatment. The below can be taken as a guide, however, depending on the patient’s clinical presentation slight variations might be acceptable as long as the team is still adhering to practising safe dentistry.

9.1 Patient position

The patient should preferably be lying flat with suitable headrest to allow saliva to collect towards the back of the mouth to aid in achieving a dry field would work the best [16, 67]. The patient can then assist the operator in either turning the head sideways, tilting back- or forwards as required, and in having the mouth either fully or partially opened to facilitate delivery of procedure stages [67].

9.2 Operator position

Operators should continue complying with the standard dentist seating positions and posture [14, 16, 67]. With as much straight back as possible, the operator should be sitting behind the patient’s head which can be slightly tilted depending on the quadrant and teeth surface.

9.3 Assistant position

When available, the assistant must sit to the left of a right-handed operator and sufficiently close to the patient to avoid leaning forward but at the same time should be approximately 10 cm higher than the operator to avoid having a restricted view. That position would also facilitate them reaching and transferring instruments and materials to the operator in the transfer zone [70].

10. The key stages involved in ART

As mentioned, ART can be used as either a preventative approach to seal caries susceptible pits and fissures or to restore early caries and simultaneously seal adjacent pits and fissures [16, 36, 37, 67]:

10.1 ART sealants using HVGIC to seal pits and fissures

1. The tooth undergoing treatment is to be isolated using cotton wool rolls and any food debris or plaque deposits removed from the pits and fissures using either a probe or a toothbrush (Figure 1-1).

2. Apply the dentine conditioner to the pits and fissures then wash off using a wet cotton pellet.

3. Cotton pellets are used to dry the occlusal surface.

4. HVGIC is mixed and applied to pits & fissures using the applier end of the instrument (Figure 1-2).

5. Pressure (press-finger technique) applied onto the occlusal surface using a lubricated finger for a few seconds until the GIC has initially set (Figure 1-3).

6. Remove finger and check that GIC has filled all pits and fissures then remove excess.

7. Check occlusion and adjust if necessary.

8. Place a fresh layer of petroleum jelly on the occlusal surface (Figure 1-4).

9. Provide post-operative instructions; avoid eating for a minimum of 1-h.

Figure 1.

Schematic representation of the steps involved in sealing non-cavitated fissures using HVGIC. In a clockwise direction: (1) Cotton wool roll isolated and debris free pits and fissure. (2) HVGIC placed over pits & fissures. (3) Finger- press over filled pits & fissures. (4) Adjusted and finished restoration.

10.2 ART restorations using HVGIC

1. Cotton wool rolls placed to isolate the tooth undergoing treatment.

2. Ensuring sufficient finger support, the tip of a sharp excavator is used to access caries.

3. During caries excavation, particular attention should be paid to removing soft dentine from Enamel-Dentine junction (EDJ).

4. In deep cavities it’s acceptable to leave some soft dentine on the pulpal floor to avoid risk of pulpal exposure.

5. Once excavation has been completed, the cavity should be rinsed then dried using cotton pellets (Figure 2-1).

6. Condition the cavity as well as the adjacent pits and fissures using 20% polyacrylic acid.

7. Restore the cavity using properly mixed HVGIC ensuring that adjacent pits and fissures are included (Figure 2-2).

8. Pressure (press-finger technique) applied onto the occlusal surface using a lubricated finger for a few seconds until the GIC has initially set (Figure 2-3).

9. Remove finger and check that GIC has filled all occlusal surface including pits and fissures then remove excess (Figure 2-4).

10. Check occlusion and adjust if necessary.

11. Place a fresh layer of petroleum jelly on the occlusal surface (Figure 2-5).

12. Provide post-operative instructions; avoid eating for a minimum of 1-h.

The above guide described ART stages for one-surface cavities. On multi-surface anterior and posterior cavities the stages are rather the same with the difference being in using the Mylar/plastic matrix strips and wedges to re-create proximal contacts.

Figure 2.

Schematic representation of the steps involved in restoring cavitated teeth using HVGIC. In a clockwise direction: (1) Carious soft tissue excavated from cavity. (2) HVGIC placed in the cavity that is slightly overfilled to include the fissures. (3) Finger- press over filled cavity and adjacent pits & fissures. (5) Adjusted and finished restoration.

11. Factors affecting success of ART

As previously mentioned, despite the fact that the ART is a simplified approach compared to conventional restorative treatments, restorations provided following ART can still fail or at least be compromised as a result of a break in the chain of delivering any of the procedure stages. In that, factors relating to the operator, materials used, or any breach in the technique stages could all compromise the success of ART restorations [71]. In clinical dentistry, the correct assessment to justify any treatment approach underpins the success of the treatment and therefore, ensuring suitability to perform ART on patients is of utmost importance [72]. Other operator-related factors include ensuring adequate moisture control, caries removal as recommended in the stages mentioned in the previous sections, and HVGIC handling relating to the material mixing and insertion [73]. Another aspect that has been frequently reported to have a significant impact on the success of ART restorations is the operator experience and training [74, 75]. Even in the presence of conflicting literature reports regarding the significance of moisture control, caries removal and material handling [74], there seems to be a general consensus on the importance of ART specific training in increasing the procedure success rates [36, 74, 75, 76, 77].

The other two factors; materials and technique, have also been reported to have an impact on the long-term success of ART restorations. These are interrelated as the former relates to proper HVGIC mixing to reach the correct consistency and the latter is about soft dentine excavation, cavity conditioning and how to properly load the mixed GIC in increments into the cavity. Additionally, using the finger technique, press first then move sideways upon removal and finishing off the restoration as described in the previous research are all factors that need to be considered to ensure longevity of final restorations [37].

12. ART combination treatment

Minimal intervention dentistry is a philosophy from which other concepts for example ART have emerged. Similar conservative approaches have also been proposed with claims that the combination of which with ART could potentially result in improved ART outcomes. One of the approaches is the use of the chemo-mechanical caries removal system Carisolv™ gel (RLS Global AB, Gothenburg, Sweden) to aid in achieving caries-free cavities prior to cavity restoration [78]. Carisolv™ gel consists of a mix of sodium hypochlorite and three amino acids and its mechanism of action is through selective dentine softening to facilitate removal with hand instruments [79]. However, despite the initial promising results, it has been found that the combination of Carisolv™ gel and ART did not modify the outcomes of ART restorations [80].

Silver Diamine fluoride (SDF), originally marketed as a desensitising agent, seems to be gaining popularity for use as an adjunct to ART to prevent and arrest dental caries in both primary and permanent teeth, a procedure which is known as Silver-modified atraumatic restorative treatment (SMART) [81]. The SDF concentration of 28%, containing 44,800 ppm fluoride, has been proven to be the mostly effective in arresting dental caries [82]. In this approach, SDF is applied just before restoring with HVGIC, however, the material is notorious for leaving a permanent black stain on the arrested carious lesions which could impair aesthetics if used on anterior teeth [83]. Furthermore, research on the quality of GIC bond strength to dentine following the application of SDF has been inconsistent with few studies reported that SDF application had either no adverse effect on the adhesion of GIC to dentine [83, 84, 85] or even a significant increase in the bond strength value of GIC to dentine post SDF application [86]. On the other hand, further research in this area have demonstrated that GIC bond strength to dentine was drastically reduced following the application of SDF [87].

Further research suggested a modified form of ART, known as ARTm, when compared to the original or true ART approach [88]. The procedure involved using a high-speed diamond bur to remove unsupported enamel only while soft dentine removal to be performed using hand instruments in accordance with the original or true ART. The authors claimed that ARTm could encourage more dental practitioner to accept and adopt the ART approach, however, despite been widely used in its country of origin (Brazil), there is a need for ARTm to be recognised and approved worldwide for which further research is needed.

As a result of the above findings, it’s clear that there is a huge lack of sound evidence to support the use of any of the aforementioned approaches in combination with ART and further research is needed to enable drawing evidence-based conclusions.

13. ART restorations and sealants survival rates

The outcome measures to indicate whether an ART restoration is successful or not have been reported to be either primary or secondary [89]. The primary outcomes are those where the treated tooth continued to be asymptomatic without any signs of caries progression either clinically or radiographically. The secondary outcome measures, however, indicate the failure of an ART restoration that necessitates either retreatment to remove secondary caries and the replacement of a failed or lost restoration, or performing more advanced treatment such as root canal treatment or even extraction [89].

ART restoration survival rates can be related to the simplicity of the treatment such as those involving single Vs multi-surface restorations. Generally speaking, single surface ART restorations using HVGIC showed significantly higher survival rates than those involved multi-surface cavities [36, 90]. One study has reported that after 12-months, class I and class V ART restorations showed approximately 80–90% success rates when compared to 55–75% and 35–55% for class III and class IV ART restorations, respectively [91]. Similar investigations also demonstrated that ART restorations that involved single surfaces had 95% and 97% one-year survival rates in primary and permanent teeth, respectively. Subsequently, the same restorations survival rates decreased to 86% and 72% after 3 years and 6 years, respectively [36].

ART restoration retention rates have been reported to be higher in the first year with a slight decrease in the following year with retention rates reduction from 81% to 66%, respectively [18]. Other studies have demonstrated comparable retention rates over a 3-year period which approximately ranged from 92% in the first year to 82% and 71% in the second & third years, respectively [92]. In general, there seems to be an increased research to support that HVGIC ART restorations have either comparable or longer survival rates than conventional restorative treatments and composite restorations [90, 92].

ART sealant survival rates on the other hand were assessed based on whether sealants have been either partially or completely dislodged over a period of three years [36]. At the one- and three-year follow-up research, HVGIC ART sealants were found to have had higher survival rates compared to using low- or medium viscosity GIC and the resin-based sealants when performed under the same application conditions [36, 93]. The above survival rates provided research evidence to further support the effectiveness of ART approach in the management of dental caries.

14. To repair or to replace failed ART restorations

When indicated, repairing defective ART restoration remains the preferred approach to replacing the whole restoration [94]. It has been stated that replacing restorations involves the likelihood of further tooth tissue loss that despite being minimal, the increased number of interventions could increase the amount of tissue loss [95]. Also, from an experience perspective, it has been reported that patients tended to have less levels of anxiety when restoration repair was planned [95].

All initial carious lesions can successfully be treated following the minimally intervention approach [96]. A new approach to define carious lesions has been devised as a guide to facilitate identification of the lesions based on their site and size [97]. ART restoration failures can vary from material wear of more than 0.5 mm, partial or complete material loss or caries around cavity margins, the management of which again varies from material top up to cavity cleaning and conditioning or complete material replacement [72].

This has placed further emphasis on the ‘means to prevent failure’ to avoid the need for repairing or replacing ART restorations starting with an accurate decision regarding the suitability of teeth to receive ART and when restoration failure exists to perform a vigilant tooth and restoration assessment to identify the failure and its best management approach.

15. ART and the Covid-19 pandemic era

Since its outbreak, Covid-19 has caused disruption to the provision of dental treatments with new guidelines released in response to regulate treatment delivery without compromising safety standards [98, 99]. As a result of the pandemic restrictions and the subsequent changes in providing routine dentistry non-aerosol generating procedures (non-AGPs) where the use of minimally or non-invasive instead of the conventional treatment approaches were highly recommended [97]. There have been a few reports indicating that using ART during the pandemic would have been successful given all the positive outcomes reported in the literature [100, 101]. Furthermore, as it does not involve the use of rotary instruments, ART is not considered an AGP and therefore requires no fallow times [102] which are known to may have an impact on the capacity for providing dental care.

Despite the fact that restrictions have eased, the Covid-19 virus and its variants are still present and every precaution should be taken to prevent the risk of the disease transmission by avoiding elective AGPs and using minimally or non-invasive approaches such as ART. Nonetheless, making appropriate clinical decisions alongside integrating prevention-centred practices should remain a cornerstone to use in adjunct to ART approach as part of embracing all minimally invasive caries management strategies.

16. Conclusion

Despite the increased focus within dental institutes in the UK and other developed countries to teach and encourage students to perform minimally invasive caries management, true ART has not gained similar popularity particularly among primary care dental practitioners. Furthermore, and in spite of the existing evidence regarding ART effectiveness as a minimally invasive caries management approach there is still a distinct lack of research regarding the perception and practice of ART in primary care settings. Operator experience remains a significant factor in achieving higher ART success rates particularly when combined with specific ART training to enhance skills to achieve best results. ART success is also dependent on careful consideration of other factors such as patient and tooth assessment to ensure suitability to receive ART with a clear emphasis on repairing failed restorations when clinically indicated rather than replacement.

Another significant aspect of the ART concept is its role in the prevention promotion programme that accompanies the restorative care. In that, an oral health care plan in the form of caries assessment and education regarding tailored prevention strategies should be determined and discussed with patients. Those should continuously be assessed and reinforced during the appropriate review appointments.

It is apparent that ART can be the alternative caries prevention and treatment approach of choice particularly in the current continuing Covid-19 era. Even with the easing pandemic restrictions, practising safe dentistry is still of paramount importance further indicating that true ART and possibly its modified forms, ARTm and SMART, would have a great potential to be appropriate caries treatment strategies and could therefore become the old-new normal caries management approaches.

Acknowledgments

The author would like to thank the University of Liverpool for supporting the publication of this chapter through completely covering the required funds.

Conflict of interest

The author declares no conflict of interest.