Histological changes in pulp-dentin complex in tooth subjected to traumatic occlusion and subluxation.

Background: This study evaluated the influence of traumatic occlusion in the dentin-pulp complex a molar teeth submitted to subluxation. Material and methods: Ninety Wistar rats were divided into groups Naïve (N), Subluxation (S) and Subluxation with traumatic occlusion (STO) and submitted to histological analysis after 7 and 21 days. A quantitative analysis was submitted to one-way ANOVA and Tukey's post-hoc test, and Chi-square and Bonferronís post-hoc test. Results: S and STO showed a significant increase in blood vessels area (p < 0.0005), amorphous fundamental substance (p < 0.0005) and reactionary dentin formation (p < 0.0005), as well as a decrease in the nuclear profile (p < 0.0005), odontoblast layer (p = 0.013 and p < 0.0005) by day 7 when compared with N. These changes normalized by day 21, except for the reactionary dentin (p < 0.0005) in both S and STO groups. Interestingly, the STO group exhibited significant changes in the increase of pulp calcification (p < 0.0005), presence of tubules with nuclei (p < 0.0005), and inflammatory infiltrate (p < 0.0005), as well reduction of nuclear profile (p < 0.0005), odontoblast layer (p < 0.0005) compared with N and S at day 21. Conclusions: STO impaired the defence response and decreased pulp regeneration capacity by increasing the inflammatory infiltrate and pulp calcification, and decreasing the nucleated cell number in the odontoblast layer and central pulp.

Systematic review of the effects of excessive occlusal mechanical load on the periodontum of rats.

OBJECTIVE: This study aims to systematically evaluate the effects of traumatic occlusion on the periodontal tissue of rats. The set of questions to be answered were-Can traumatic occlusion acting on a healthy and an unhealthy periodontium cause periodontal destruction? DESIGN: The protocols for systematic review were all developed, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement and applied to animal research. Reporting of In vivo experiment guidelines for reporting animal research to assess the risk of bias of the studies. MATERIALS AND METHODS: A literature search was conducted using MEDLINE through PubMed and manual search from the reference lists of main articles related to the theme. RESULTS: This search strategy identified 65 references, of which 33 were considered inappropriate. The full texts of 32 articles were read, 31 of which did not meet the eligibility criteria and were excluded. The final selection included 1 article for which data was extracted for further evaluation. The article included shows a strongest reaction in the periodontium in front of a secondary occlusal trauma as inflammation and apical migration of the junctional epithelium, bone degradation, and decrease in the quantity of collagen fiber. However, primary occlusal trauma also presents these alterations, with the exception of apical migration of the junctional epithelium. CONCLUSIONS: Although only one study was included in the systematic review of traumatic occlusion, there is some evidence from experimental studies on animals that shows a coherent picture of the effects of traumatic occlusion on the periodontium. However, new studies are needed to fully answer the questions posed by this systematic review.

Immediate tooth replantation: root canal filling for delayed initiation of endodontic treatment.

The aim of this study is to evaluate the action of paramonochlorophenol associated with Furacin followed by calcium hydroxide (CH) dressing in the control of inflammatory root resorption in cases of immediate tooth replantation with delayed endodontic treatment. A total of 28 incisors of 3 male dogs were extracted and replanted after 15 minutes, and randomly divided into 3 groups: Group I (n = 8) - endodontic treatment was performed before the extraction and replantation; Group II (n = 10) - endodontic treatment was performed 30 days after replantation and the root canal was filled with CH dressing; Group III (n = 10) - endodontic treatment was performed 30 days after replantation and root canals received temporary medication of paramonochlorophenol-Furacin followed by CH dressing. The animals were euthanized 90 days after replantation. The histomorphological events analyzed at the epithelial reattachment site were the intensity and extent of acute and chronic inflammatory processes, periodontal ligament (PDL) organization, the intensity and extent of acute and chronic inflammatory processes in the PDL space, root resorption, bone tissue, and ankylosis. Data were submitted to the Wilcoxon Signed Ranks Test for group comparison (α = 5%). In Groups I, II and III the periodontal ligament was regenerated and most of the resorption areas were repaired by newly formed cementum. The depth and extent of root resorption were significantly higher in Group II than in Group III. The use of paramonochlorophenol-furacin followed by CH dressing was more effective in controlling inflammatory root resorption after immediate tooth replantation.

Immediate tooth replantation: root canal filling for delayed initiation of endodontic treatment

Abstract The aim of this study is to evaluate the action of paramonochlorophenol associated with Furacin followed by calcium hydroxide (CH) dressing in the control of inflammatory root resorption in cases of immediate tooth replantation with delayed endodontic treatment. A total of 28 incisors of 3 male dogs were extracted and replanted after 15 minutes, and randomly divided into 3 groups: Group I (n = 8) - endodontic treatment was performed before the extraction and replantation; Group II (n = 10) - endodontic treatment was performed 30 days after replantation and the root canal was filled with CH dressing; Group III (n = 10) - endodontic treatment was performed 30 days after replantation and root canals received temporary medication of paramonochlorophenol-Furacin followed by CH dressing. The animals were euthanized 90 days after replantation. The histomorphological events analyzed at the epithelial reattachment site were the intensity and extent of acute and chronic inflammatory processes, periodontal ligament (PDL) organization, the intensity and extent of acute and chronic inflammatory processes in the PDL space, root resorption, bone tissue, and ankylosis. Data were submitted to the Wilcoxon Signed Ranks Test for group comparison (α = 5%). In Groups I, II and III the periodontal ligament was regenerated and most of the resorption areas were repaired by newly formed cementum. The depth and extent of root resorption were significantly higher in Group II than in Group III. The use of paramonochlorophenol-furacin followed by CH dressing was more effective in controlling inflammatory root resorption after immediate tooth replantation.

Influência da oclusão traumática no processo de reparo do periodonto em dentes submetidos a luxação extrusiva / Influence of traumatic occlusion on the periodontal repair process in teeth submitted to extrusive luxation

O tratamento luxação extrusiva visa o reparo das estruturas de suporte do periodonto com o dente em posição original, contudo pode ser prejudicado por alguns fatores como a oclusão traumática. Este estudo avaliou a influência da oclusão traumática no processo de reparo dos tecidos de suporte periodontais de dentes que sofreram luxação extrusiva. Sessenta ratos Winstar foram divididos em três grupos: Grupo Controle (n=20), Grupo Luxação Extrusiva (n=20) e Grupo Luxação Extrusiva e Oclusão Traumática (n=20), nos períodos experimentais de 7 e 30 dias. O dente de estudo foi o primeiro molar inferior direito. A luxação extrusiva foi simulada pela indução de forças no sentido axial até o seu deslocamento e reposição do dente por pressão digital. A oclusão traumática foi induzida por restauração de resina composta e fio metálico na superfície oclusal, criando uma plataforma plana.Cortes histológicos longitudinais foram corados com hematoxilina e eosina, Picrosirius red e técnica imunoistoquímica para detecção da TRAcP. Foi avaliada a reabsorção óssea e dentária, área de fibras colágenas, matriz extracelular não fibrilar e vasos sanguíneos, número de perfil nuclear e células TRAcP, organização do ligamento periodontal, extensão e intensidade do processo inflamatório. O teste de Kruskal-Wallis e post hoc de Dunn foram utilizados para a comparação entre os grupos (α=0,05). Dentre as diferenças significativas observou-se: aos 7 dias um aumento de células TRAcP e uma diminuição da área óssea do septo inter-radicular em L e LOT, bem como um aumento da reabsorção óssea marginal no grupo LOT quando comparado ao grupo controle; aos 30 dias, as fibras colágenas tipo I tiveram um aumento no grupo L, bem como, aumento da reabsorção óssea marginal nos grupos experimentais. No modelo experimental estudado, a oclusão traumática gerou prejuízo significativo na recuperação nas estruturas de suporte do dente submetido a luxação extrusiva a curto prazo(AU)

The extrusive luxation treatment aims to repair the structures of the periodontium with the tooth in original position, however it can be impaired by some factors such as traumatic occlusion. This study aims to evaluate the influence of traumatic occlusion on the repairing process of the periodontal tissues of the tooth submitted to extruded luxation. Sixty Winstar rats was divided into three groups: Control group (n=20), Extrusive luxation group (n=20) and Extrusive luxation and Traumatic Occlusion group(=20), in the experimental periods of 7 and 30 days. The experimental tooth was the first lower right molar. The extrusive luxation was simulated by the induction of forces in the axial direction until its displacement and replacement of the tooth by digital pressure. Traumatic occlusion was induced by restoration of composite resin and metallic wire on the occlusal surface, creating a flat platform. Longitudinal histological sections were stained with hematoxylin and eosin, Picrosirius red and immunohistochemical technique for the detection of TRAcP. Bone and dental resorption, area of collagen fibers, extracellular non-fibrillar matrix and blood vessels, number of nuclear profile and TRAcP cells, periodontal ligament organization, extent and intensity of the inflammatory process were evaluated. The Kruskal-Wallis and post hoc Dunn tests were used to compare the groups (α = 0.05). Among the significant differences were observed at 7 days an increase of TRAcP cells and a decrease of the interradicular septum bone area in the L and LTO groups, as well as an increase in the marginal bone resorption in the LTO group when compared to the control group; at 30 days, type I collagen fibers had an increase in the L group, as well as increased marginal bone resorption in the experimental groups. In the experimental model studied, traumatic occlusion generate a significanty impairment in the recovery of the periodontal support structures of the tooth submitted to extrusive luxation in a short period(AU)

The influence of traumatic occlusion on the repair process for teeth following subluxation.

BACKGROUND/AIM: Traumatic occlusion (TO) can cause morphofunctional alterations that interfere in the homeostasis of the periodontium. The aim of this study was to assess the influence of TO on the periodontal repair process for teeth following subluxation. MATERIALS AND METHODS: Ninety Wistar rats aged 12 weeks were divided into three groups: control (C), subluxation (S) and subluxation with traumatic occlusion (S+TO). Subluxation was created with an impact force of 900 cN applied by a tensiometer and TO was created with a direct composite resin filling. Healing after two experimental periods of 7 and 21 days was assessed histologically. The Kruskal-Wallis and Dunn post hoc tests were used for group comparison. RESULTS: At 7 days, there was a significant increase in periodontal ligament (PDL) width and amorphous fundamental substance, as well as a significant bone area reduction in groups S and S+TO. After 21 days, there was a significant PDL width increase in group S+TO, and in the percentage of collagen fibres in group S, whereas group S+TO showed a 52% bone area reduction compared to the same group at 7 days. Subluxation with or without TO caused only superficial root resorption. However, only group S+TO showed damage to the repair process of resorbed root areas after 21 days. CONCLUSION: TO can increase damage to the PDL after subluxation and it can also delay the repair process after PDL damage.