Reabsorção radicular externa cervical invasiva: revisão de literatura / Invasive external cervical root resorrption: literature review

A reabsorção externa cervical (REC) caracteriza-se pela invasão da região cervical da raiz pelo tecido fibrovascular nas fases iniciais e, em seguida, por tecido fibro-ósseo que progressivamente reabsorve o cemento, a dentina e o esmalte. De acordo com Heithersay (2004) podem ser classificadas em 4 estágios de acordo com suas características clinicas e radiográficas. A REC é uma entidade insidiosa e, por isso, seu diagnóstico é eminentemente radiográfico. Uma vez identificada, a TCCB é um exame complementar essencial para o planejamento do melhor plano de tratamento por permitir a localização do ponto de início da reabsorção e da natureza do processo. A etiologia da REC ainda é mal compreendida Sabe-se que seu início depende da lesão ou deficiência da camada de cemento na região cervical da raiz, logo abaixo do epitélio juncional, na região correspondente à junção amelocementária. O tratamento ortodôntico, o traumatismo dentário, o clareamento endógeno e os procedimentos cirúrgicos representam os principais fatores predisponentes por resultarem na quebra de homeostasia desta região. Uma vez instalada a reabsorção, a natureza do estímulo necessário para sustentar a REC também gera discussões. Alguns autores o consideram puramente inflamatório, enquanto outros como reabsorção asséptica que pode ser invadida, secundariamente, por microrganismos oriundos do sulco gengival e, mais raramente dos túbulos dentinários em dentes com polpa necrótica. O tratamento cirúrgico/restaurador está indicado nas REC em estágios iniciais e médios classificação 1,2 e 3 de Heythersay, 1999. Quanto mais precoce o diagnostico maiores os índices de sucesso. As reabsorções classificadas como classe 4 tem baixa taxa de sucesso após o tratament

External cervical resorption (ECR), also called invasive cervical resorption (ICR), is defined as a localized resorptive process that commences on the surface of root below the epithelial attachment and the coronal aspect of the supporting alveolar process, namely the zone of the connective tissue attachment. It is an aggressive type of external resorption characterized by invasion of the cervical region of the root by fibrovascular tissue in the early stages and then by fibro-osseous tissue that progressively reabsorbs cementum, dentin and enamel.The resorptive cavity contains granulomatous fibrovascular tissue separated from the healthy pulp tissue by a thin layer of dentin and predentin, called pericanalar resorption resistant sheet (PRRS). According to Heithersay (2004) they can be classified in 4 stages according to their clinical and radiographic features. Because the majority of cases of REC is an insidious asymptomatic entity, the diagnosis is mostly made during routine radiographic examination. Cone-beam computed tomography (CBCT) is also used as a complementary technique to asses and manage this type of resorption. The onset of REC depends on the presence of gaps in the cement layer in the cervical region of the root, just below the junctional epithelium. Orthodontics, dental trauma, endogenous bleaching and surgical procedures represent the main predisposing factors. Additional factors that continuously stimulate the resorptive cells rendering ERC progressive are not well known. Some authors consider it purely inflammatory while others as aseptic resorption that can be contaminated by microorganisms originating from the gingival sulcus and, more rarely, from the pulp canal trough dentinal tubules. in teeth with necrotic pulp. Surgical/restorative treatment is indicated in the stages 1 to 3 (Heythersay, 1999) achieving higher success rates in earlier diagnosis. Teeth diagnosed with stage 4 of REC have puor prognosis

Effects of the bisphosphonate alendronate on molars of young rats after lateral luxation.

BACKGROUND AND AIM: The bisphosphonate alendronate (ALN) was employed with the aim of investigating its effects on dental and periodontal tissues after lateral luxation of developing molars. MATERIAL AND METHODS: Twenty-one-day-old Wistar rats had their second upper molars laterally luxated. Daily 2.5 mg kg(-1) ALN injections started at the day of the luxation; controls received sterile saline solution. The teeth were analyzed 7, 14, and 21 days after the procedure. On the days cited, the maxillae were fixed, decalcified, and embedded in paraffin or Spurr resin. The paraffin sections were stained with H&E, incubated for TRAP histochemistry or immunolabeled for osteopontin (OPN). Spurr ultrathin sections were examined in a transmission electron microscope. RESULTS: After 21 days, the root apex of luxated molars without ALN was wide open and disorganized and also covered by an irregular layer of cellular cementum, which was not observed in ALN-treated animals. Ankylosis sites were observed in ALN rats in both luxated and non-luxated teeth. The TRAP-positive osteoclasts were more numerous in ALN group, despite their latent ultrastructural appearance without the presence of resorption apparatus compared to controls. OPN immunolabeling revealed a thick immunopositive line in the dentin that must be resultant from the moment of the luxation, while ALN-treated specimens did not present alterations in dentin. CONCLUSION: The present findings indicate that alendronate inhibits some alterations in dentin and cementum formation induced by dental trauma.

Microscopic evaluation of induced tooth movement after subluxation trauma: an experimental study in rats.

OBJECTIVE: The objective of this study was to assess the histological alterations that occurred in the periodontal area of rat molars submitted to induced tooth movement (ITM) right after an intentional trauma (subluxation). METHODS: Forty adult male Wistar rats (Rattus norvegicus albinus) were selected. The animals were divided into eight groups (n=5), according to the combination of variables: Group 1--control (neither trauma nor ITM); Group 2--ITM; Groups 3, 4, 5 and 6--dentoalveolar trauma groups corresponding, respectively, to 1, 3, 8 and 10 days after trauma; Groups 7 and 8 - the animals' molars were subjected to a 900 cN impact and, one and three days after the trauma event, tooth movement was induced. The rats' maxillary first molars were mesially moved during seven days with a closed coil (50 cN). After the experimental period of each group, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. RESULTS: In the animals of group 3, 4, 5 and 6, the histological alterations were not very significant. Consequently, the effect of induced tooth movement right after a subluxation event (groups 7 and 8) was very similar to those described for Group 2. CONCLUSIONS: There was no difference in the quality of periodontal repair when ITM was applied to teeth that had suffered a subluxation trauma.

Microscopic evaluation of induced tooth movement after subluxation trauma: an experimental study in rats

OBJECTIVE: The objective of this study was to assess the histological alterations that occurred in the periodontal area of rat molars submitted to induced tooth movement (ITM) right after an intentional trauma (subluxation). METHODS: Forty adult male Wistar rats (Rattus norvegicus albinus) were selected. The animals were divided into eight groups (n = 5), according to the combination of variables: Group 1 - control (neither trauma nor ITM); Group 2 - ITM; Groups 3, 4, 5 and 6 - dentoalveolar trauma groups corresponding, respectively, to 1, 3, 8 and 10 days after trauma; Groups 7 and 8 - the animals' molars were subjected to a 900 cN impact and, one and three days after the trauma event, tooth movement was induced. The rats' maxillary first molars were mesially moved during seven days with a closed coil (50 cN). After the experimental period of each group, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. RESULTS: In the animals of group 3, 4, 5 and 6, the histological alterations were not very significant. Consequently, the effect of induced tooth movement right after a subluxation event (groups 7 and 8) was very similar to those described for Group 2. CONCLUSION: There was no difference in the quality of periodontal repair when ITM was applied to teeth that had suffered a subluxation trauma. .

OBJETIVO: avaliar as alterações histológicas ocorridas na área periodontal de molares de ratos submetidos à movimentação dentária induzida (MDI), logo após um trauma intencional (subluxação). MÉTODOS: quarenta ratos Wistar machos adultos (Rattus norvegicus albinus) foram selecionados. Os animais foram divididos em oito grupos (n = 5), de acordo com a combinação das variáveis: Grupo 1 - controle (sem trauma e sem MDI); Grupo 2 - MDI; Grupos 3, 4, 5 e 6 - grupos de trauma dentoalveolar correspondendo, respectivamente, para 1, 3, 8 e 10 dias após o trauma; Grupos 7 e 8 - os molares murinos foram submetidos a um impacto de 900cN e, de um e três dias após o evento trauma, o movimento do dente foi induzido. Os primeiros molares superiores dos animais foram movidos mesialmente durante sete dias, com uma mola fechada (50cN). Após período experimental de cada grupo, os animais foram sacrificados por overdose anestésica e as maxilas direitas foram removidas e processadas para análise histológica qualitativa. RESULTADOS: nos animais dos grupos 3, 4, 5 e 6, as alterações histológicas não foram muito significativas. Consequentemente, o efeito do movimento dentário induzido logo após um evento de subluxação (grupos 7 e 8) foi muito semelhante ao descrito para o grupo 2. CONCLUSÃO: não houve diferença na qualidade do reparo periodontal quando a MDI foi aplicada aos dentes que sofreram um trauma de subluxação. .

Root repair after contact with mini-implants: systematic review of the literature.

This systematic review identified and qualified the current evidence of dental root damage and repair after contact with mini-implants. The electronic databases Cochrane library, Ovid, Scirus, Scopus, and Virtual Health Library were used to search original articles from 1980 to December 2011. The inclusion criteria to select the articles were 1. randomized controlled trials and prospective clinical studies based on trials involving humans, 2. randomized controlled studies in animals, 3. use of mini-implants with a diameter less than 2.5 mm, and 4. root contact evaluation associated with the use of orthodontic mini-implants. Two authors independently reviewed and extracted data from the selected studies and a methodological quality assessment process was used to rank the studies classifying them as low moderate or high quality. The searches retrieved 579 citations. After initial selection, 17 studies were considered eligible and their full texts were assessed. Four of those were excluded because root damage was not evaluated and two were excluded because of overlapping samples. Eleven articles, nine in animals and two in humans, fulfilled the inclusion criteria. From these, two studies were ranked as presenting high methodological quality, eight were judged to be of moderate, and one of low quality. The evidence found suggested that the quality of root repair depends on the amount of damage caused by the mini-implant. When the damage is limited to the cementum or dentin, healing and almost complete and repair of the periodontal structure can occur. Mini-implants that injured the pulp were less likely to result in complete repair of the periodontal tissues.

Root resorption on torqued human premolars shown by tartrate-resistant acid phosphatase histochemistry and transmission electron microscopy.

OBJECTIVE: To identify clastic cells on the root surfaces of torqued human premolars. MATERIALS AND METHODS: A continuous force of 600 cNmm was applied to upper first premolars in patients 13-16 years of age by using a precise biomechanical model with superelastic wires (NiTi-SE). The 28 teeth in 14 patients were divided into five groups (control [nonmoved], and moved for either 1, 2, 3, or 4 weeks) and processed for tartrate-resistant acid phosphatase (TRAP) histochemistry and transmission electron microscopy. RESULTS: Mononuclear TRAP-positive cells appeared at 2 weeks, where as large multinucleated TRAP-positive cells were numerous at 3 and 4 weeks. Ultrastructural examination revealed many clastic cells in contact with resorption lacunae. In addition, some cementoblast-like cells appeared secreting new cementum over previously resorbed lacunae. CONCLUSIONS: In general, resorption lacunae and the number of clastic cells, which increased with the duration of the applied force, were found on the cementum surface at the pressure areas. Some signs of cementum repair were also noticed, even with the maintenance of the level of the force.

Estudio de la frecuencia relativa de las lesiones productoras de cemento en pacientes con enfermedad periodontal / Study of the relative incidence of the lesions productor of cement in patient with periodontal disease

Se revisaron 779 historias clínicas de pacientes que acudieron al Post-Grado de Periodoncia de la Facultad de Odontología de la Universidad Central de Venezuela, de 1977 a 1987, en edades comprendidas de 11 a 60 años. Se examinó el aspecto radiográfico para identificar las afecciones cementógenas