Traditional operative dentistry approach to deep caries treatment advocated its total removal using slow-speed rotary burs and hand instruments [11]. Complete excavation removes all the infected and affected dentin.

The second method of deep caries excavation is termed stepwise excavation and is done over two patient visits. The first excavation is intended to remove the superficial necrotic, infected, and affected dentin by completely excavating the periphery of the lesion. This excavation does not excavate caries near the pulp to avoid a pulp exposure [20]. A retentive temporary restoration is placed leaving soft, moist, discolored dentin on the pulpal floor. The dentin is then covered with calcium hydroxide and a self-setting glass ionomer temporary filling [17] (Fig. 4.2). A resin-modified glass ionomer has also been advocated in place of the self-setting glass ionomer [21]. SW is intended to allow remineralization of the affected dentin and formation of more tertiary dentin [20]. The carious lesion is reentered in 8–12 weeks by removing the temporary, and a final complete excavation is done leaving only central yellowish or grayish hard dentin in the pulpal floor (Fig. 4.3). A final restoration is placed with the intention to seal the pulp from any microleakage [17]. In two systematic reviews and meta-analysis studies [12, 13], SW significantly reduced pulp exposures compared to complete excavation (Fig. 4.4).

The third type of caries excavation is termed partial or incomplete excavation involving one appointment removal of the peripheral decay but intentionally leaving the deepest caries in place to avoid a pulp exposure. An indirect pulp treatment is then completed (Fig. 4.5).

Partial excavation omits the reentry and second excavation done in SW by sealing off the caries with a final restoration placed at the same appointment [12] (Fig. 4.6).

Partial excavation attempts to shift the microbial balance within the affected dentin to promote dentin remineralization and arrest the carious lesion [22]. Maltz et al. [23, 24] published the results of one randomized controlled trial (RCT) comparing stepwise to partial excavation in 299 permanent molars in two time frames. The results of the 2- and 3-year follow-up showed significantly higher success rates of one appointment partial caries excavation compared with SW (96 % and 91 % compared with 81 % and 61 % after 2 years and 3 years, respectively). Maltz et al. speculated on why stepwise excavation success was only 61 % after 3 years [24]. The authors felt some SW patients did not return for the final excavation and restoration in 1–2 months, and the success rate in these patients was very low (13 %). Patients treated with SW that had a final excavation and permanent restoration had survival rates not statistically different from those of partial excavation (88 % with SW vs. 91 % partial excavation) [24].

The last form of caries treatment has been reported in primary teeth. It involves no drilling or excavation of any caries and would be termed no caries excavation. A steel crown to seal the caries and stop its progress is used [25]. The technique is termed the Hall technique (named after Norma Hall, a Scottish dentist) and presumes that sealing the infected and affected dentin from microleakage will arrest the caries [25, 26]. There have been published reports testing the Hall technique success versus conventional restorations [27, 28]. Ludwig et al. [27] reported in a retrospective study that 65 of 67 steel crowns placed using the Hall technique were successful after a meantime of 15 months. In an RCT report after 12 months, the Hall technique crowns were significantly better (p = 0.002) than using conventional complete excavation and a compomer restoration [28]. Whether the Hall technique is indicated for use in teeth with deep dentinal caries is yet unknown. In a 10-year prospective study [29], frank carious lesions in permanent teeth that extended radiographically into less than half the dentin were sealed. No caries excavation was done, and the caries was sealed in place with a self-setting occlusal sealant. The report showed arrest of the lesions over 10 years if the occlusal sealant stayed intact. The study’s purpose was not intended to promote leaving caries unexcavated, but to show if caries was sealed in place by a sealant, it would not progress [29].

The IPT procedure is normally done in one appointment but can be done as a modification of the SW procedure in two visits. An IPT begins with removal of the superficial infected dentin using a high-speed water-cooled bur [33]. First, the decay in the periphery of the lesion is excavated completely using slow-speed burs such as #4 or #6. Using the same slow-speed bur, partial excavation of superficial decay on the pulpal floor is done, leaving some decay and not exposing the pulp [33]. Using an excavator for the pulpal floor, excavation may remove large pieces of dentin, which can result in a pulp exposure. The amount of decay remaining appears not to be critical, as dentin remineralization occurs irrespective of the amount of decay remaining [34, 35]. The decay remaining is mostly affected dentin. It may appear moist and soft or dark and leathery, but the dentin color and consistency are not critical to IPT success. If a biological seal is created with a final restoration, the remaining bacteria in the dentin are believed to be nonviable, and the affected dentin will remineralize and become harder [20, 34]. A steel crown or a well-bonded composite resin will prevent any microleakage and maximize the likelihood of success (Fig. 4.7).