Analysis of hard tissue regeneration and Wnt signalling in dental pulp tissues after direct pulp capping with different materials

Abstract

Aim To investigate the involvement of Wnt signalling and cell cycle regulation in hard tissue formation after pulp capping with several materials in a rat molar pinpoint exposure model. Methodology Thirty‐two rat molar pulps were mechanically exposed and assigned to 4 groups according to the pulp capping materials used Ca(OH)2, mineral trioxide aggregate (MTA), Biodentine™ and an untreated control group. After 4 weeks, the teeth were collected for microcomputed tomography to quantify reparative dentine formation. Histological analysis was then performed to evaluate the quality of the reparative dentine and the dental pulp tissue inflammatory reaction. Cyclin D1 and β‐catenin expression was examined using immunofluorescence staining. The Kruskal–Wallis followed by Dunn’s multiple comparison test was performed to determine significant differences. Results The exposed dental pulps treated with Ca(OH)2, MTA and Biodentine™ exhibited reparative dentine formation near the exposure site. Fibrous tissues adjacent to the exposure site were observed in the untreated group. The microcomputed tomography evaluation of MTA and Biodentine™ groups revealed significantly greater reparative dentine formation compared with the control group (P = 0.0032 in the MTA group and P = 0.05 in the BiodentineTM group). From histological evaluations, the BiodentineTM group exhibited significantly greater reparative dentine formation grading compared with the control group (P = 0.0152). The pulp tissues treated with Ca(OH)2 and Biodentine™ exhibited a lower inflammatory score compared with those of the untreated control (P = 0.0291 in the Ca(OH)2 and P = 0.0110 in the BiodentineTM group). Ca(OH)2, MTA and Biodentine™ induced cyclin D1 expression in the dental pulp tissues adjacent to the reparative dentine. Moreover, the Biodentine™‐treated defects demonstrated β‐catenin expression in the pulp tissue adjacent to the newly formed reparative dentine, which was not observed with the other materials. Conclusion All test materials promoted dentine bridge formation and stimulated cyclin D1 expression. The favourable outcome after direct pulp capping with Biodentine™ involved Wnt/β‐catenin signalling. However, Wnt/β‐catenin signalling did not participate in the mechanism by which Ca(OH)2 and MTA promoted reparative dentine formation.

A novel bio‐active adhesive monomer induces odontoblast differentiation: a comparative study

“…The high concentration of OHprovides a strong alkaline environment to eliminate possible bacterial infection. However, this reactivity is high and indiscriminate, which may also cause irritation and damage to odontoblasts, leading to the necrosis and disintegration of adjacent tissue (Yaemkleebbua et al 2019); furthermore, a necrotic layer can stimulate the inflammatory response, which further induces deep pulp tissue regeneration potential (Giraud et al Figure 3 Effects of CMET on the mRNA expression of odontogenic differentiation markers. Cells were cultured in DMEM supplemented with 5% FBS and different concentrations of CMET, dH2O was employed as a control, 10 mmol L À1 b-GP and 50 lg mL À1 AA were added from day 5.…”

Efeito da associação de meio condicionado por células tronco de polpa dentária humana e MTA ProRoot no reparo de polpas expostas de ratos

“…Antes disso, o MC por células-tronco de polpa dentária humana já havia sido utilizado em modelos in vivo em ratos em terapias de regeneração pulpar (Murakami et al, 2015;De Cara et al, 2019) Os tempos experimentais utilizados para análise da formação de dentina reparadora variam muito na literatura. A grande maioria dos estudos costuma fazer as análises após 4 semanas do procedimento de capeamento pulpar (Khalil et al, 2013;Liu et al, 2015;Chang et al, 2016;Kim et al, 2016;Liu et al, 2017;Long et al, 2017;Okamoto et al, 2018;Yaemkleebbua et al, 2019). Entretanto, pouquíssimos estudos avaliaram os efeitos de materiais capeadores como MTA e Biodentine após períodos mais longos do que esse.…”

“…Essa classificação foi baseada inicialmente no método proposto por Koike et al (2014), com algumas modificações. Outros trabalhos (Moazzami et al, 2014;Chang et al, 2016;Long et al, 2017;Liu et al, 2017;Okamoto et al, 2018;Trongkji et al, 2018;Yaemkleebbua et al, 2019) também se basearam em classificações qualitativas para análise destas variáveis. Para minimizar os vieses inerentes a análises qualitativas, as lâminas foram avaliadas por um patologista experiente na área e todas as amostras foram randomizadas e cegadas para o avaliador em questão.…”

“…Estes resultados vão de acordo com o encontrado em outros estudos (Long et al, 2017;Yaemkleebbua et al, 2019) (Simon et al, 2008;Ricucci et al, 2014;Dammaschke et al 2019).…”

“…Regeneração refere-se à proliferação de células e tecidos a fim de substituir as células e tecidos perdidos ou danificados, com restauração da estrutura normal do tecido. Por outro lado, a cicatrização refere-se a uma resposta à lesão que envolve a formação de um tecido com características de fibrose, com estrutura tecidual permanentemente alterada (Gurtner et al, 2008 (Khalil et al, 2013;Moazzami et al, 2014;Liu et al, 2015;Chang et al, 2016;Long et al, 2017;Liu et al, 2017;Okamoto et al, 2018;Trongkji et al, 2018;Yaemkleebbua et al, 2019) ou microtomográficas (Kim et al, 2016;Okamoto et al, 2018;Yaemkleebbua et al, 2019). Contudo, os resultados sobre a morfologia e organização da dentina reparadora ainda é um assunto bastante discutido.…”