Analysis of the dentin-pulp complex in teeth submitted to orthodontic movement in rats

In order to microscopically analyze the pulpal effects of orthodontic movement, 49 maxillary first molars of rats were submitted to orthodontic appliance composed of a closed coil spring anchored to the maxillary incisors, placed for the achievement of mesial movement. MATERIAL AND METHODS: Ten animals were used as the control group and were not submitted to orthodontic force; the other animals were divided into groups according to the study period of tooth movement, namely 1, 2, 3, 4, 5, 6 and 7 days. The investigation of pulp and periodontal changes included hyalinization, fibrosis, reactive dentin and vascular congestion. Statistical evaluation was performed between control and experimental groups and between periods of observation using non-parametric chi-square, Kruskal-Wallis and Dunn tests. RESULTS: There was no statistically significant difference concerning pulpal changes between control and experimental groups nor between periods of observation. The control group, at 3 and 5 days, revealed greater hyalinization of the periodontal ligament (p<0.05), whereas root resorption was significantly greater at 5 and 7 days (p<0.05). CONCLUSION: No morphological change from the effect of induced tooth movement could be found in the dentin-pulp complex. In addition, no inflammatory or pulp degeneration, detectable in optical microscopy, was found in experimental groups

Analysis of the dentin-pulp complex in teeth submitted to orthodontic movement in rats

In order to microscopically analyze the pulpal effects of orthodontic movement, 49 maxillary first molars of rats were submitted to orthodontic appliance composed of a closed coil spring anchored to the maxillary incisors, placed for the achievement of mesial movement. MATERIAL AND METHODS: Ten animals were used as the control group and were not submitted to orthodontic force; the other animals were divided into groups according to the study period of tooth movement, namely 1, 2, 3, 4, 5, 6 and 7 days. The investigation of pulp and periodontal changes included hyalinization, fibrosis, reactive dentin and vascular congestion. Statistical evaluation was performed between control and experimental groups and between periods of observation using non-parametric chi-square, Kruskal-Wallis and Dunn tests. RESULTS: There was no statistically significant difference concerning pulpal changes between control and experimental groups nor between periods of observation. The control group, at 3 and 5 days, revealed greater hyalinization of the periodontal ligament (

Biology of induced tooth movement and associated root resorption: the influence of the gender and bisphosphonates

O presente trabalho discutiu os mecanismos biológicos envolvidos na movimentação dentária induzida e as possíveis consequências deste procedimento, essencial para o tratamento ortodôntico. O estudo do movimento dentário induzido em animais tem como objetivo compreender as reações dos tecidos envolvidos e analisar as variáveis que podem interferir na mecânica ortodôntica aplicada. Assim, pode-se prevenir o efeito mais indesejado de um tratamento ortodôntico: a reabsorção dentária associada. Histomorfometricamente analisou-se a influência do gênero na movimentação dentária em ratos da linhagem Wistar, nos períodos de 3, 5, 7 e 9 dias de movimentação, quando se concluiu que não houve diferença estatisticamente significante na frequência e nas dimensões das reabsorções radiculares entre os gêneros nos diferentes períodos experimentais analisados (p&#8804;0,05). Fatores externos também podem influenciar nas reações teciduais frente à movimentação dentária induzida e na ocorrência das reabsorções radiculares. Desta forma, o estudo também analisou o efeito dos bisfosfonatos, o alendronato, na densidade óssea, já que os bisfosfonatos são reconhecidamente potentes inibidores da reabsorção óssea. Também em ratos Wistar e utilizando histomorfometria determinou-se a densidade óssea alveolar maxilar em cortes transversais na região entre as raízes do primeiro molar murino. Os resultados revelaram que não houve diferença estatisticamente significante na densidade óssea alveolar entre os animais que receberam alendronato e o grupo controle (p=0,3754). De acordo com a metodologia utilizada, pôde-se concluir que o bisfosfonato do tipo alendronato não altera morfologicamente a qualidade óssea alveolar, mantendo as características estruturais e mecânicas do tecido em animais saudáveis. Fatores como o gênero e o uso de bisfosfonatos do tipo alendronato não influenciam de forma decisiva os fenômenos biológicos da movimentação dentária. Este fato pôde ser exemplificado em um relato de caso clínico de um paciente do gênero feminino e que fez uso de alendronato. Os tratamentos ortodôntico e reabilitador foram executados sem qualquer complicação, após minucioso procedimento de anamnese, diagnóstico e plano de tratamento, podendo ser assim restabelecida a condição estética e funcional ideal para o paciente.The work talked over the biologic mechanisms involved on induced tooth movement and the possible consequences, essential in orthodontic treatment. The tooth movement research in animals has the objective to understand the reactions of the involved tissues and analyze the variables that can interfere in the orthodontic treatment. Thus, we can avoid undesirable effects of the orthodontic treatment such as the external root resorption. The influence of the gender on tooth movement in Wistar rats was quantified by histomorphometry, at the periods of 3, 5, 7 and 9 days of tooth movement. There was no statiscally significant difference in the frequency and in the dimensions of root resorptions between the genders in the analyzed periods (p&#8804;0.05). External factors such as the use of biphosphonate, also may have some influence on the tissue reactions when induced tooth movement is applied and also on the occurrence of root resorption. Therefore, the study also aimed to evaluate the influence of the bisphosphonates (alendronate) on bone density, since the bisphosphonates are recognized as a potent inhibitor of bone resorption. Wistar rats were used to determine histomorphometricly the maxillary bone density. For this, transverse sections in the region between the roots of the first rat up molar were taken. The results showed no statistically significant difference when alveolar bone density was evaluated between the alendronate and the control group (p=0.3754). It can be concluded that the alendronate may not change alveolar bone density, probably keeping the structural and mechanic properties of the tissue in healthy rats. Within the limits of the present study, it can be concluded that gender and the use of alendronate may not influence the tissue reactions when induced tooth movement is applied. This fact could be exemplified in a clinical case of a female patient who used alendronate. The orthodontic and rehabilitation treatments have been carried out without any complication. A careful medical history, diagnosis, and treatment plan were essential and thus, the aesthetic and functional condition could be reestablished for the patient

Cone-beam computerized tomographic, radiographic, and histologic evaluation of periapical repair in dogs` post-endodontic treatment

Objective. To evaluate the periapical repair after root canal treatment in the teeth of dogs using CT and conventional radiography and to compare these findings with the gold standard microscopic evaluation. Study design. The animals were divided into three groups according to endodontic treatment performed: Group 1, single-visit endodontic treatment in teeth without apical periodontitis; Group 2, single-visit endodontic treatment in teeth with apical periodontitis; and Group 3, endodontic treatment in teeth with apical periodontitis using calcium hydroxide as a root canal dressing. Group 4 consisted of teeth with apical periodontitis not submitted to root canal treatment and Group 5 consisted of healthy teeth without periapical disease. Radiographic, tomographic, and microscopic evaluations were performed by blind examiners. At 180 days experimental time, CT and radiographic measurements of periapical disease were compared with the gold standard microscopic measurement using intraclass correlation coefficient. Intergroup comparisons considering different methods of periapical lesions measurement or different clinical protocols of root canal treatment were performed by Kruskal Wallis test followed by Dunn. Integrity of lamina dura, presence of radiolucent areas, and presence of root resorption were analyzed by Fisher`s exact test. Results. There was discontinuity of the lamina dura and CPD in all teeth from Groups 2, 3, and 4 evaluated by tomography and radiography 45 days after CPD induction. Radiographically, 180 days after root canal treatment, there was no periapical lesion in teeth from Groups 1 and 3, different from groups 2 and 4 (p < .05). The highest reduction in the CPD size was observed on Group 3 (p < .05). According to the tomographic results, there was decrease of the size of the CPD on Group 3 but not on Groups 2 or 4. However, in all groups the periapical lesions presented larger mesio-distal extension if compared with radiography, both 45 days after CPD induction and 180 days after root canal treatment. At 180 days, CT measurements were closely related to microscopic results (ICC = 0.95) differently from radiographic evaluation (ICC = 0.86). Conclusion. CT Scan evaluation of periapical repair following root canal treatment provided similar information than that obtained by microscopic analysis, whereas radiographic evaluation underestimated the size do periapical lesion. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108:796-805

Effect of GaAIAs low-level laser therapy on the healing of human palate mucosa after connective tissue graft harvesting: randomized clinical trial

Among the available techniques to treat gingival recession, connective tissue graft (CTG) presents more foreseeability and better results in the long term. However, this technique causes morbidity and discomfort in the palatine region due to graft removal at that site. The aim of this clinical trial was to evaluate the influence of low-level laser therapy (LLLT) on the healing of the donor palatine area after CTG. Thirty-two patients presenting buccal gingival recession were selected and randomly assigned to receive LLLT irradiation (test group) or LLLT sham (control group) in the palatine area after connective graft removal. A diode laser (AsGaAl, 660 nm) was applied to test the sites immediately after surgery and every other day for 7 days. The evaluated parameters were wound remaining area (WRA), scar and tissue colorimetry (TC), tissue thickness (TT), and postoperative discomfort (D). These parameters were evaluated at baseline and 7, 14, 45, 60, and 90 days after surgery. Two-way repeated measures ANOVA was used for analysis. The test group presented statistically significant smaller wounds at days 14 and 45. None of the patients presented a scar at the operated area, and colorimetry analysis revealed that there was no statistically significant difference between groups (p > 0.05). Patients reported mild to moderate discomfort, with low consumption of analgesic pills. We concluded that LLLT irradiation can accelerate wound healing on palatine mucosa after connective tissue removal for root coverage techniques (ClinicalTrial.org NCT02239042).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP