The reparative mechanisms that operate following carious and traumatic dental injury are critical for pulp survival and involve a series of highly conserved processes. It appears that these processes share genetic programs—linked to cytoskeletal organization, cell movement, and differentiation—that occur throughout embryogenesis. Reactionary dentin is secreted by surviving odontoblasts in response to moderate stimuli, leading to an increase in metabolic activity. In severe injury, necrotic odontoblasts are replaced by other pulp cells, which are able to differentiate into odontoblast-like cells and produce a reparative dentin. This complex process requires the collaborative efforts of cells of different lineage. The behavior of each of the contributing cell types during the phases of proliferation, migration, and matrix synthesis as well as details of how growth factors control wound cell activities are beginning to emerge. In this review, we discuss what is known about the molecular mechanisms involved in dental repair.

The aim was to appraise the evidence on the performance of various means for the detection of incipient caries in vivo. Five databases of published and unpublished research were searched for studies from January 2000 to October 2019. Search terms included “early caries” and “caries detection.” Inclusion criteria involved diagnostic test accuracy studies for early caries detection in permanent and primary teeth. A risk-of-bias assessment was performed using the QUADAS-2 tool. We performed the study selection, data extraction, and risk-of-bias assessment in duplicate. The review protocol was a priori registered in the Open Science Framework. Of the initially 22,964 search results, 51 articles were included. For permanent teeth, when histologic examination was considered as the reference for occlusal surfaces, the sensitivity (Se) range appeared high for the DIAGNOdent Pen (DD Pen) at 0.81–0.89, followed by ICDAS-II at 0.62–1, DIAGNOdent (DD) at 0.48–1, and bitewing radiography (BW) at 0–0.29. The corresponding specificity (Sp) range was: DD Pen 0.71–0.8, ICDAS-II 0.5–0.84, DD 0.54–1, and BW 0.96–1. When operative intervention served as the reference for occlusal surfaces, again, the DD means valued the most promising results on Se: DD 0.7–0.96 and DD Pen 0.55–0.90, followed by ICDAS-II 0.25–0.93, and BW 0–0.83. The Sp range was: DD 0.54–1, DD Pen 0.71–1, ICDAS-II 0.44–1, and BW 0.6–1. For approximal surfaces, the Se was: BW 0.75–0.83, DD Pen 0.6, and ICDAS-II 0.54; the Sp was: BW 0.6–0.9, DD Pen 0.2, and ICDAS-II 1. For primary teeth, under the reference of histologic assessment, the Se range for occlusal surfaces was: DD 0.55–1, DD Pen 0.63–1, ICDAS-II 0.42–1, and BW 0.31–0.96; the respective Sp was: DD 0.5–1, DD Pen 0.44–1, ICDAS-II 0.61–1, and BW 0.79–0.98. For approximal surfaces, the Se range was: DD Pen 0.58–0.63, ICDAS-II 0.42–0.55, and BW 0.14–0.71. The corresponding Sp range was: DD Pen 0.85–0.87, ICDAS-II 0.73–0.93, and BW 0.79–0.98. Se and Sp values varied, due to the heterogeneity regarding the setting of individual studies. Evidently, robust conclusions cannot be drawn, and different diagnostic means should be used as adjuncts to clinical examination. In permanent teeth, visual examination may be enhanced by DD on occlusal surfaces and BW on approximal surfaces. In primary teeth, DD Pen may serve as a supplementary tool across all surfaces.