Immediate reimplantation of primary teeth: a histological study in dogs

Reimplantation of primary teeth has been the subject of various clinical and histological studies, but very little is known about the effect of this treatment on primary teeth. The aim of the present study was to histologically evaluate the biological response of dog primary teeth after immediate reimplantation. Twelve dogs were divided into two groups according to postoperative time: 1 week and 3 weeks. Twenty-one upper and lower intermediate incisors were extracted and submitted to endodontic treatment, reimplantation and splinting. The 21 homologous teeth not submitted to treatment served as controls. The animals were killed after the respective experimental periods, and the obtained specimens were processed for histological analysis. Most dogs of the 1-week group exhibited the following alterations: gingival epithelium was inserted in the cemento-enamel junction, with a small number of chronic inflammatory cells being observed in the gingival corium; the periodontal ligament was partially reestablished, with a more expressive chronic inflammatory infiltrate being observed in the apical third; small root resorption was observed on the palatine/lingual side in the apical third. In contrast, in 3-week animals, gingival epithelial insertion was predominantly absent on the buccal side, and a moderate chronic inflammatory infiltrate was present; the periodontal ligament generally showed no bone-cementum reinsertion especially on the palatine/lingual side, with an expressive inflammatory infiltrate in the apical region, and large root resorption was mainly observed on the palatine and lingual sides. In conclusion, reimplantation causes histological alterations in the tooth and its supporting periodontal structures that suggest the impossibility of its maintenance.

Análise radiográfica computadorizada da reabsorção radicular apical após a utilização de duas mecânicas ortodônticas

OBJETIVO: a reabsorção radicular apical é uma condição comumente observada durante e após o tratamento ortodôntico e fatores como tipo de aparelhagem ortodôntica utilizada, magnitude das forças aplicadas e duração do tratamento podem estar relacionados ao processo de arredondamento do ápice radicular. Buscou-se avaliar, por meio de imagens radiográficas computadorizadas, a quantidade de reabsorção no ápice radicular, quando da utilização de duas diferentes técnicas de mecânica ortodôntica fixa: Edgewise com acessórios padrão e Edgewise com acessórios totalmente programados. METODOLOGIA: a amostra constituiu-se de 20 pacientes tratados pelo mesmo profissional na Clínica de Ortodontia da Faculdade de Odontologia de Araçatuba - UNESP. Os pacientes foram divididos em dois grupos: grupo 1 (Tratados com Edgewise com acessórios padrão e fios de aço) e grupo 2 (Tratados com Edgewise com acessórios totalmente programados e fios de níquel-titânio). A avaliação radiográfica digital foi realizada por um único operador por meio de exposições radiográficas digitais feitas no início do tratamento ortodôntico, após retração de caninos e final de tratamento, utilizando o sistema de escores proposto por Levander e Malmgren (1988). RESULTADOS E CONCLUSÕES: a análise dos escores permitiu concluir que o tratamento ortodôntico empregando a técnica Edgewise com acessórios totalmente programados e fios de níquel-titânio apresentou menores graus de reabsorção radicular apical, em comparação à técnica Edgewise com acessórios padrão e fios de aço. Observou-se que, independentemente da técnica empregada, o tratamento ortodôntico como um todo apresentou um grau moderado de reabsorção radicular apical.

Influence of the type of vehicle and limit of obturation on apical and periapical tissue response in dogs' teeth after root canal filling with mineral trioxide aggregate

The purpose of this study was to investigate the influence of the type of vehicle (distilled water or propyleneglycol) on the response of apical tissues of dogs' teeth after root canal filling with mineral trioxide aggregate (MTA) at two different limits. Forty roots of incisors and premolars of two adult dogs were used. After pulpectomy, the root canals were prepared biomechanically, and the roots had the apical cemental barrier penetrated with a #15 K-file and widened to a #25 K-file. The root canals were assigned to four groups according to the vehicle used for MTA (ProRoot-MTA; Tulsa Dental, Tulsa, OK) preparation and the limit of root canal filling: group 1, filling with MTA/distilled water to the limit of the cemental canal; group 2, overfilling with MTA/distilled water, group 3, filling with MTA/propyleneglycol to the limit of the cemental canal; and group 4, overfilling with MTAlpropyleneglycol. The animals were killed by anesthetic overdose 90 days after endodontic treatment and the anatomic pieces were prepared for histomorphological analysis. The sections were stained with hematoxylin and eosin and Brown and Brenn techniques. The results showed that MTA pastes prepared with either distilled water or propyleneglycol as vehicles had similar biological behavior (p > 0.05); root fillings placed at the cemental canal limit showed better results than the overfillings (p = 0.01), and MTA/propyleneglycol paste was more easily placed into the root canals than MTA/distilled water paste.

Influence of apical patency and filling material on healing process of dogs' teeth with vital pulp after root canal therapy

Foi propósito deste trabalho observar o processo de reparo de dentes de cães após obturação dos canais com dois cimentos diferentes, fazendo ou não a patência apical. Após uma sobreinstrumentação, os canais receberam um curativo de uma solução de corticosteróide-antibiótico por 7 dias, com o objetivo de obter invaginação de tecido conjuntivo para dentro dos canais. Após esse período, esse tecido foi totalmente removido em metade dos casos (grupos com patência apical) e preservados no restante dos casos (grupos sem patência apical). Os canais foram obturados pela técnica da condensação lateral empregando um cimento a base de hidróxido de cálcio (Sealer Plus) ou um cimento de Grossman (Fill Canal). Os animais foram sacrificados por overdose anestésica 60 dias após o tratamento endodôntico e as peças anatômicas foram obtidas e preparadas para análise histológica. Os dados obtidos foram analisados com base em diversos parâmetros histomorfológicos. Os resultados foram melhores nos grupos sem patência apical (p=0,01) do que nos grupos com patência. Dentre os cimentos estudados, os melhores resultados foram observados com o cimento Sealer Plus (p=0,01). em conclusão, tanto a patência apical (presença ou ausência) quanto o tipo de material obturador de canal influíram no processo de reparo apical de dentes de cães com polpas vitais após tratamento endodôntico. O emprego de um cimento a base de hidróxido de cálcio em dentes sem patência apical promoveu os melhores resultados, dentre as condições experimentais propostas.

Antimicrobial potential of medicaments used in healing process in dogs' teeth with apical periodontitis

Estudou-se a influência de diferentes irrigantes no potencial antimicrobiano da pasta de hidróxido de cálcio em dentes de cães com periodontite apical. 48 pré-molares de cães adultos tiveram suas câmaras coronárias abertas e expostas à cavidade bucal por 6 meses. Os canais radiculares foram preparados, irrigados e medicados com diferentes substâncias, de acordo com os seguintes grupos: 1) 2,5% NaOCl + CHP; 2) 2% CHX + CHP; 3) vinagre + CHP; 4) vinagre + vinagre. No grupo 4, a solução irrigante e a medicação intracanal utilizada foi o vinagre. Neste grupo, a cada 7 dias, a solução era renovada. Cada amostra foi coletada, mantendo-se o cone de papel esterilizado em posição por 1 min, e a seguir transportado e imerso em 7 mL de Letheen broth, seguido de incubação a 37ºC por 48 h. O crescimento microbiano foi analisado por dois métodos, turbidade do meio de cultura e subcultura em meio nutritivo específico (brain heart infusion). Os resultados mostraram que em todos os grupos experimentais houve crescimento microbiano após 21 dias, em diferentes percentagens: grupo 1 - 30%; grupo 2 - 30%; grupo 3 - 40%; grupo 4 - 60%. Todos os materiais testados apresentaram potencial antimicrobiano. Entretanto, o processo de cura favorecido pela pasta de hidróxido de cálcio não pode ser esquecido, uma vez que muitos estudos já demonstraram sua ação antimicrobiana.

Evaluation of the apical infiltration after root canal disruption and obturation

The aim of this study was to evaluate two root canal filling techniques used in teeth that had their apical foramen disrupted and compare the apical infiltration with an ideal clinical situation. Twenty-seven freshly extracted single-rooted teeth were selected and radiographed to confirm the existence of a single and straight root canal. The crowns were removed at a mean distance of 11 mm from the apex. The teeth had the root canals instrumented and were randomly assigned to 3 groups (n=9): ND group-root canals were filled using the lateral compaction technique and no disruption was performed; DRF group-the apical constriction was disrupted by advancing a #40 K-file 1 mm beyond the original working length, the canals were reinstrumented to create an apical ledge at 1 mm from the apical foramen and were obturated with a master gutta-percha cone with same size as the last file used for reinstrumentation; DF group - the teeth had the apical constriction disrupted and the canals were obturated with a master gutta-percha cone that fit at 1 mm from the apex. The teeth were submitted to dye leakage test with Rhodamine B for 7 days, using vaccum on the initial 5 min. The teeth were sectioned longitudinally and the leakage was measured in a linear fashion from apex to crown. There was no statistically significant difference (p>0.05) between the groups that had the apical foramen disrupted (DF, DRF), but significant difference was found between the disrupted groups and the non-disrupted one (p<0.01). In conclusion, none of the evaluated techniques was able to prevent apical infiltration, so working length so the working length determination has to be established and maintained carefully.

Histologic evaluation of the use of membrane, bone graft, and MTA in apical surgery

The aim of this study was to evaluate the periapical healing after the use of membrane, bone graft, and mineral trioxide aggregate (MTA) in apical surgery of dogs' teeth. Apical lesions were induced in 48 roots of 6 dogs after coronal access and pulpal removal. Apical surgery consisted of osteotomy with trephine bur for the standardization of the critical surgical cavities, followed by apicoectomy, curettage, preparation of the root-end cavities with the aid of the ultrasonic device, and retrofilling with MTA. The surgical sites were divided into: group 1-filled with blood; group 2-filled with blood and recovered with membrane; group 3-filled with bone graft; and group 4-filled with bone graft and recovered with membrane. The results showed that the inflammatory infiltrate, the periapical healing process, and the behavior of MTA was the same in all groups, including the mineralization stimulation. It was concluded that the use of membranes and bone graft materials isolated or associated in apical surgery did not alter the periapical healing process after the root-end filling with MTA. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 309-314)

Subgingival microbiota from Cebus apella (capuchin monkey) with different periodontal conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Conservative management of a dentigerous cyst secondary to primary tooth trauma

Pulp necrosis is a commonly observed sequela in traumatized primary teeth and is one of the possible etiologic factors for the development of dentigerous teeth. This article reports the case of a dentigerous cyst associated with the germ of a permanent maxillary central incisor that developed secondary to trauma to the predecessor primary incisor. The therapeutic approach included endodontic treatment of the primary tooth and marsupialization of the lesion. After 36 months of follow up, the permanent incisor presented with normal physiologic conditions, absence of dental anomalies and erupted in its correct position in the oral cavity. In conclusion, with proper case selection, marsupialization might be a good treatment option for conservative management of dentigerous cysts.

Orthodontic movement of teeth with intraosseous defects: histologic and histometric study in dogs

The purpose of this study was to evaluate histologically, in dogs, the periodontal healing of 1-walled intraosseous defects in teeth that were subjected to orthodontic movement toward the defects. The defects were surgically created bilaterally at the mesial aspects of the maxillary second premolars and distal aspects of the mandibular second premolars of 4 mongrel dogs. One week after creating the defects, an orthodontic appliance was installed, and the teeth were randomly assigned to 1 of 2 treatment groups: those in the test group received a titanium-molybdenum alloy rectangular wire spring that performed a controlled tipping root movement, and those in the control group received a passive stainless steel wire. Active orthodontic movement of the test teeth lasted 2 months and was followed by a stabilization period of another 2 months, after which the animals were killed. Throughout the study, routine daily plaque control was performed on the dogs with a topical application of a 2% chlorhexicline gel. The results showed no difference between the groups, with some regularization of the defects and periodontal regeneration limited to the apical portion of the defects. Histometric analysis showed a significant difference in bone height; on average, it was 0.53 mm smaller in the test group. It was concluded that orthodontic movement does not interfere with the healing of 1-walled intraosseous defects, with the exception of the linear extent of new bone apposition.

Orthodontic movement after periodontal regeneration of class II furcation: a pilot study in dogs

Purpose: the effect of orthodontic movement on the periodontal tissues of maxillary second pre-molars, after regenerative treatment for class II furcations, was evaluated in four mongrel dogs.Material and Methods: Class II furcation lesions were created. After 75 days they were treated with bovine bone mineral matrix and guided tissue regeneration with absorbable membrane. After 2 months of daily plaque control, each of the dog's furcation pre-molars was randomly assigned to a test or control group. Orthodontic appliances were placed on both sides of the maxilla using third pre-molars and canines as anchorages. In the test group, bodily orthodontic movement of the second pre-molars was performed in the mesial direction for 3 months while control pre-molars remained unmoved. The dogs were sacrificed for histometric and histologic analyses.Results: There were no statistically significant differences between the two groups in total bone and biomaterial areas or linear extension of periodontal regeneration on the radicular surfaces. In the test group, however, there was a tendency to a greater quantity of bone and a lesser quantity of biomaterial.Conclusion: the orthodontic movement was not pre-judicial to the results obtained with the regenerative periodontal treatment.

Accuracy of zoomed digital image in the detection of periodontal bone defect: in vitro study

Objectives: (1) To evaluate the intraobserver agreement related to image interpretation and (2) to compare the accuracy of 100%, 200% and 400% zoomed digital images in the detection of simulated periodontal bone defects.Methods: Periodontal bone defects were created in 60 pig hemi-mandibles with slow-speed burs 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm and 3.0 mm in diameter. 180 standardized digital radiographs were made using Schick sensor and evaluated at 100%, 200% and 400% zooming. The intraobserver agreement was estimated by Kappa statistic (kappa). For the evaluation of diagnostic accuracy receiver operating characteristic (ROC) analysis was performed followed by chi-square test to compare the areas under ROC curves according to each level of zooming.Results: For 100%, 200% and 400% zooming the intraobserver agreement was moderate (kappa = 0.48, kappa = 0.54 and kappa = 0.43, respectively) and there were similar performances in the discrimination capacity, with ROC areas of 0.8611 (95% CI: 0.7660-0.9562), 0.8600 (95% CI: 0.7659-0.9540), and 0.8368 (95% CI: 0.7346-0.9390), respectively, with no statistical significant differences (chi(2)-test; P = 0.8440).Conclusions: A moderate intraobserver agreement was observed in the classification of periodontal bone defects and the 100%, 200% and 400% zoomed digital images presented similar performances in the detection of periodontal bone defects.