Continued root maturation despite persistent apical periodontitis of immature permanent teeth after failed regenerative endodontic therapy

Abstract

Three immature permanent teeth with pulp necrosis and apical periodontitis were treated with regenerative endodontic therapy (RET), which included root canal disinfection with sodium hypochlorite irrigation, intra-canal medication with calcium hydroxide paste, 17% EDTA rinse, induction of periapical bleeding into the canal, collagen matrix and MTA coronal seal, and composite resin restoration of access cavities. After different periods of follow-up, it was observed that continued root maturation, especially apical closure occurred despite persistent apical periodontitis of immature permanent teeth after failed RET. This finding is of interest as the secondary goal of further root maturation occurred despite failure of the primary goal of elimination of clinical symptom/sign and periapical inflammation. The possible biological mechanisms that could allow for further root maturation to occur in spite of persistent root canal infection of immature permanent teeth are discussed. Based on these observations, the biology of wound healing of immature permanent teeth after injury is not fully understood and should be further investigated. This case report demonstrates that whilst further root maturation is considered a successful outcome for teeth treated with RET, the primary objective must be the resolution of the signs and symptoms of apical periodontitis.

Pulp regeneration with hemostatic matrices as a scaffold in an immature tooth minipig model

“…Conventionally, continued root maturation of immature teeth with residual inflammation or recurrent inflammation after RET was rarely possible because the primary goal failed to be achieved 42 . However, several recent case reports have shown that root maturation with immature teeth could be achieved even with persistent apical periodontitis in unsuccessful RETs, which is consistent with the findings in the present study 43 , 44 . In the current study, all teeth of the experimental groups exhibited newly mineralized tissue formation and apex maturation in the histologic analysis except for the NC group (Table 3 ).…”

“…Root development in failed RET teeth with inflammatory changes may result from the survival of resident or migrated stem cells to maintain their characterization despite persistent apical periodontitis. In addition, the specificity of immature teeth, which have powerful immune defenses and vascular innervation to respond to tissue injury, may allow the coexistence of root maturation and apical periodontitis 44 .…”

Regenerative endodontics: a comprehensive review

“…, Lin et al . ). Therefore, root maturation of immature permanent teeth with apical periodontitis after RET is desirable only when the apical periodontitis resolves.…”

Stem Cells From the Apical Papilla (SCAP) as a Tool for Endogenous Tissue Regeneration

“…Compared to BM MSCs, SCAP adipogenesis was found to be of a lower quality since only a few detectable lipid droplets were seen after 3 weeks (Dong et al, 2013 ; Xu et al, 2013 ; Hilkens et al, 2014 ; Lin et al, 2018 ). Concluding that not only SCAP, but also DPSCs are inferior to BM MSCs when it comes to adipogenic potentiality.…”

“…Despite both the dental pulp and apical papilla being basically a continuity of one another, when necrosis strikes the pulp, the apical papilla combats the pulp and tends to survive due to its accessibility to a collateral circulation apically (Huang et al, 2008 ; Diogenes and Hargreaves, 2017 ). Therefore, justifying how immature teeth with necrotic pulps are able to undergo completion of root development/ apexogenesis sometimes even with persistence of signs and symptoms indicative of apical periodontitis; further elucidates the infection-resistant nature of SCAP (Chrepa et al, 2017 ; Lin et al, 2018 ). The apical papilla and consequently SCAP can be easily isolated following tooth extraction by separating the tissue at the tips of the developing roots by tweezers.…”