Short-term vs long-term calcium hydroxide therapy after immediate tooth replantation: a histomorphometric study in monkey's teeth

Endodontic treatment is an important step of tooth replantation protocols, but the ideal moment for definitive obturation of replanted teeth has not yet been established. In this study, a histomorphometric analysis was undertaken to evaluate the repair process on immediate replantation of monkeys teeth after calcium hydroxide (CH) therapy for 1 and 6 months followed by root canal filling with a CH-based sealer (Sealapex (R)). The maxillary and mandibular lateral incisors of five female Cebus apella monkeys were extracted, kept in sterile saline for 15 min, replanted and splinted with stainless steel orthodontic wire and composite resin for 10 days. In Group I (control), definitive root canal filling was performed before tooth extraction. In Groups II and III, CH therapy started after removal of splint, and definitive root canal filling was performed 1 and 6 months later, respectively. The animals were euthanized 9 months after replantation, and specimens were processed for histomorphometric analysis. In all groups, epithelial attachment occurred at the cementoenamel junction or very close to this region; the areas of resorption on root surface had small extension and depth and were repaired by newly formed cementum; and the periodontal ligament was organized. Statistical analysis of the scores obtained for the histomorphometric parameters did not show any statistically significant difference (P = 0.1221) among the groups. The results suggests that when endodontic treatment is initiated 10 days after immediate replantation and an antibiotic regimen is associated, definitive root canal filling can be performed after a short-term CH therapy.

Influence of enamel matrix derivative (Emdogain((R))) and sodium fluoride on the healing process in delayed tooth replantation: histologic and histometric analysis in rats

Although it has already been shown that enamel matrix derivative (Emdogain((R))) promotes periodontal regeneration in the treatment of intrabony periodontal defects, there is little information concerning its regenerative capacity in cases of delayed tooth replantation. To evaluate the alterations in the periodontal healing of replanted teeth after use of Emdogain((R)), the central incisors of 24 Wistar rats (Rattus norvegicus albinus) were extracted and left on the bench for 6 h. Thereafter, the dental papilla and the enamel organ of each tooth were sectioned for pulp removal by a retrograde way and the canal was irrigated with 1% sodium hypochlorite. The teeth were assigned to two groups:in group I, root surface was treated with 1% sodium hypochlorite for 10 min (changing the solution every 5 min), rinsed with saline for 10 min and immersed in 2% acidulated-phosphate sodium fluoride for 10 min; in group II, root surfaces were treated in the same way as described above, except for the application of Emdogain((R)) instead of sodium fluoride. The teeth were filled with calcium hydroxide (in group II right before Emdogain((R)) was applied) and replanted. All animals received antibiotic therapy. The rats were killed by anesthetic overdose 10 and 60 days after replantation. The pieces containing the replanted teeth were removed, fixated, decalcified and paraffin-embedded. Semi-serial 6-mu m-thick sections were obtained and stained with hematoxylin and eosin for histologic and histometric analyses. The use of 2% acidulated-phosphate sodium fluoride provided more areas of replacement resorption. The use of Emdogain((R)) resulted in more areas of ankylosis and was therefore not able to avoid dentoalveolar ankylosis. It may be concluded that neither 2% acidulated-phosphate sodium fluoride nor Emdogain((R)) were able to prevent root resorption in delayed tooth replantation in rats.

Healing process of incisor teeth of diabetic rats replanted after storage in milk

Several local factors that influence the healing process of replanted teeth have been investigated. However, it remains unclear how systemic alterations, such as diabetes mellitus, affect the prognosis of these cases. The purpose of this study was to evaluate the healing process of incisors of non-controlled diabetic rats replanted after storage in bovine long shelf-life (UHT) whole milk. Thirty-two rats were randomly assigned to receive an endovenous injection of either citrate buffer solution (group I - control; n = 16) or streptozotocin dissolved in citrate buffer solution to induce diabetes (group II; n = 16). After confirmation of the diabetic status by analysis of the glycemic levels, the maxillary right incisor of each animal was extracted and immersed in milk for 60 min. The root canals of teeth were then instrumented, and were filled with a calcium hydroxide-based dressing and replanted into their sockets. All animals received systemic antibiotic and were killed by anesthetic overdose 10 and 60 days after replantation. The specimens containing the replanted teeth were removed, fixed, decalcified, and embedded in paraffin. Semi-serial 6-mu m-thick sections were obtained and stained with hematoxylin and eosin for histologic and histometric analyses. The results showed that the connective tissue adjacent to the root surface was less organized in the diabetic animals than in the control animals in both periods; the root dentin was less severely affected by root resorption in the diabetic rats; there were no significant differences between the control and diabetic groups regarding the occurrence of replacement resorption and inflammatory resorption.

Use of vitamin C in delayed tooth replantation

O objetivo deste trabalho foi avaliar microscopicamente, em reimplantes tardios de dentes de rato, os efeitos do tratamento da superfície radicular com diferentes soluções. Foram utilizados 30 ratos Rattus norvegicus albinos da linhagem Wistar que tiveram seus incisivos centrais extraídos e deixados sobre a bancada por 6 h. As polpas foram extirpadas e os canais irrigados com solução de hipoclorito de sódio a 1%. Após o preparo endodôntico, a superfície radicular de cada dente foi tratada com solução de hipoclorito de sódio a 1% por 10 min (trocada a cada 5 min) seguida de soro fisiológico por 10 min, e os dentes foram divididos em três grupos com 10 espécimes em cada um. Nos Grupos I, II e III, respectivamente, a superfície radicular foi tratada com fluoreto de sódio fosfato acidulado a 2%, vitamina C e vitamina C efervescente (2 g, Redoxon®). Após obturação com pasta de hidróxido de cálcio os dentes foram reimplantados e os animais foram sacrificados aos 10 e 60 dias. O Grupo I apresentou maiores áreas de reabsorção por substituição e anquilose. Comparando as formas de vitamina C utilizadas, a efervescente (Grupo III) foi a que apresentou resultados mais favoráveis com mais áreas de anquilose e reabsorção por substituição que áreas de reabsorção inflamatória.

Microscopic evaluation of induced tooth movement in traumatized teeth: an experimental study in rats

The clinical management of orthodontic patients with dental trauma before or during the treatment is mainly founded on clinical experience, expert opinions, and individual case reports. It is proposed in the literature that teeth sustaining mild trauma with minor damage to the periodontium (e.g. subluxation) should be followed for a period of time before being subjected to orthodontic forces. A minimum period of 3 months has been proposed. In this study, we used an animal model to investigate whether shorter observation periods could be established in case of mild trauma. The periradicular region of rat molars was examined microscopically to determine the biological events of tooth movement started 15 and 30 days after intentional subluxation using an experimental method to induce dentoalveolar trauma. Thirty adult male Wistar rats were assigned to 6 groups (n = 5): Group 1 (control no trauma/orthodontic movement); Group 2: the animals received an orthodontic device and were sacrificed after 7 days; Groups 3 and 4: dentoalveolar trauma (subluxation) was experimentally induced by the application of an axial force of 900 cN on the occlusal surface of the maxillary right first molar, and the animals were sacrificed after 22 and 37 days, respectively; and Groups 5 and 6: 15 and 30 days, respectively, after force application, an orthodontic device was installed and the rats were sacrificed 7 days later. In G5 and G6, the periodontal ligament and pulp tissue were rich in cellular elements and blood vessels, the alveolar bone was preserved, and the root surface presented only very small areas of surface resorption (cementum), maintaining the characteristics of normality. In conclusion, the microscopic alterations in the gingival and periodontal tissues in response to an experimentally induced mild dentoalveolar trauma simulating subluxation were not sufficient to contraindicate starting the orthodontic movement 15 and 30 days after trauma.

Propolis as storage media for avulsed teeth: microscopic and morphometric analysis in rats

The maintenance of the avulsed teeth in appropriate media for preserving the cellular viability has been important for repairing the periodontal ligament and preventing the root resorption after tooth reimplantation. Propolis is a substance capable of preserving cellular viability. This study aimed to analyze the propolis substance as a storage media for maintaining the avulsed teeth, besides to determine the ideal time period for keeping the tooth inside it. Thus, 60 maxillary right central incisors of rats were extracted and divided into five groups. In groups I and II, teeth were kept in propolis for 60 min and 6 h, respectively; in group III, teeth were kept in milk for 6 h; in group IV, teeth were kept dry for 60 min; and in group V, they were immediately reimplanted. All teeth had their root canals filled with calcium hydroxide paste. Following, teeth were reimplanted in their sockets. After 15 and 60 days, animals were killed and the obtained samples were processed in laboratory for microscopic and morphometric analyzing. The results showed that the occurrence of inflammatory resorption, dental ankylosis and the formation of the connective tissue parallel to the root surface were similar among groups. It could be verified a greater occurrence of replacement resorption in group IV when comparing to other groups. In groups I and IV, the presence of periodontal ligament-like connective tissue was substantially smaller than the other groups. Regarding to the cementum amount over the root, it could be observed that this was present in smaller amount in groups I and IV. Group II was similar to groups III and IV. Therefore, according to the results of this study, the use of propolis as a storage media for maintaining avulsed teeth could be highlighted, and the 6-h period was more appropriate than the 60-min period.

Effect of low-level laser therapy on the healing process after tooth replantation: a histomorphometrical and immunohistochemical analysis

Success of tooth replantation is limited because part of the replanted tooth is lost because of progressive root resorption. This study used histomorphometry and immunohistochemistry to evaluate the effect of low-level laser therapy (LLLT) on the healing process of rat teeth replanted after different extra-oral periods, simulating immediate and delayed replantation. Sixty Wistar rats (Rattus norvegicus albinus) had their maxillary right incisors extracted and randomly assigned to six groups (n = 10): C4, C30 and C45, in which the teeth were replanted 4 min (immediate), 30 min (delayed) and 45 min (delayed) after extraction, respectively, and L4, L30 and L45, in which the teeth were replanted after the same extra-alveolar times, but the root surfaces and the alveolar wounds were irradiated with a gallium-aluminum-arsenate (GaAlAs) diode laser before replantation. The animals were sacrificed after 60 days. The anatomic pieces containing the replanted teeth were obtained and processed for either histomorphometrical analysis under optical microscopy or immunohistochemical expression of receptor activator of nuclear factor Kappa-B (RANK), and its ligand (RANKL), osteoprotegerin (OPG) and tartrate-resistant acid phosphatase (TRAP) proteins. Areas of external replacement and inflammatory root resorption were observed in all groups, without statistically significant differences (P > 0.05). Ankylosis was more frequent in L30 than in C30 (P < 0.05). RANKL immunostaining predominated over RANK and OPG immunostaining in both groups with immediate tooth replantation (P < 0.05). For the 45-min extra-alveolar time, however, there was greater evidence of RANK immunostaining compared to RANKL for both control and laser-treated groups (P < 0.05). Positive TRAP immunostaining predominated in L4 and L30 (P < 0.05). In conclusion, under the tested conditions, the treatment of the root surface and the alveolar wound with LLLT did not improve the healing process after immediate and delayed tooth replantation in rats.

Delayed replantation of rat teeth after use of reconstituted powdered milk as a storage medium

Minimal extraoral dry storage period and moist storage for the avulsed tooth are identified as key steps for the treatment protocol of tooth replantation. Among the possible moist storage media, bovine milk has stood out because of its capacity of preserving the integrity of the periodontal ligament (PDL) fibers. This condition has attracted the attention to investigate the use of powdered milk, which is one of the presentation forms of bovine milk, as a feasible storage medium in cases of delayed tooth replantation. The aim of this study was to evaluate the healing process after delayed replantation of rat teeth stored in reconstituted powdered milk and long shelf-life (ultra high temperature) whole milk. Forty maxillary right rat incisors were assigned to four groups (n = 10): group I - the teeth were extracted and immediately replanted into theirs sockets; group II - the teeth were stored for 60 min in 200 ml of freshly reconstituted powdered milk; group III - the teeth were stored for 60 min in 200 ml of long shelf-life whole milk; group IV - the teeth were kept dry for the same time. All procedures were performed at room temperature. Next, the root canals of teeth in groups II, III, and IV were instrumented, filled with a calcium hydroxide-based paste, and replanted into their sockets. All animals received systemic antibiotic therapy and were killed by anesthetic overdose 60 days after replantation. The pieces containing the replanted teeth were removed, fixed, decalcified, and paraffin-embedded. Semi-serial 6-mu m-thick sections were obtained and stained with hematoxylin and eosin for histomorphological analysis. There was statistically significant difference (P < 0.05) between groups I and IV regarding the presence of replacement resorption and PDL remnants on root surface. The powdered milk and long shelf-life whole milk presented similar results to each other and may be indicated as storage media for avulsed teeth.

Functional Aesthetic Treatment of Patient With Phenytoin-Induced Gingival Overgrowth

Gingival overgrowth (GO) may be related to the frequent use of certain medications, such as cyclosporin, phenytoin (PHT), and nifedipine, and is therefore denominated drug-induced GO. This article reports a case of a patient who with chronic periodontitis made use of PHT and presented generalized GO. A 30-year-old man with GO was referred to the clinic of the Universidade Estadual Paulista, Brazil. The complaint was poor aesthetics because of the GO. The patient had a medical history of a controlled epileptic state, and PHT was administered as an anticonvulsant medication. The clinical examination showed generalized edematous gingival tissues and presence of bacterial plaque and calculus on the surfaces of the teeth. The diagnosis was GO associated with PHT because no other risk factors were identified. Treatment consisted of meticulous oral hygiene instruction, scaling, root surface instrumentation, prophylaxis, and daily chlorhexidine mouth rinses. After this stage, periodontal surgery was performed, and histopathologic evaluation was made. The patient has been under control for 3 years after the periodontal surgery, and up to the present time, there has been no recurrence. It can be concluded that PHT associated with the presence of irritants favored gingival growth and that the association of nonsurgical and surgical periodontal therapies was effective in the treatment of GO. Besides, motivating the patient to maintain oral hygiene is a prerequisite for the maintenance of periodontal health.

The influence of short-term diabetes mellitus and insulin therapy on alveolar bone loss in rats

Background: It is well known that the multiple direct and indirect consequences of hyperglycemia in diabetic individuals have been linked to a number of abnormal host effector mechanisms that could lead to an increased risk of developing periodontal disease.Objective: the aim of this study was to investigate the effect of short-term experimental diabetes and insulin therapy on the severity of alveolar bone loss in rats, and the effect of experimental periodontitis on glycemic control.Methods: Seventy-two male Wistar rats were divided into four groups: group I animals were submitted to dental ligature around lower right first molars (ligated); group II consisted of streptozotocin (STZ)-diabetic, ligated rats; group III represented STZ-diabetic, unligated rats; and group IV consisted of insulin-treated (6 U/day), STZ-diabetic, ligated rats. Blood glucose of all diabetic rats was monitored at regular intervals. Standardized digital radiographs were taken after killing at 7, 15 and 30 days to measure the amount of bone loss about the mesial root surface of the first molar tooth in each rat.Results: No significant (p < 0.05) changes in plasma glucose levels of insulin-treated diabetic rats were found among the different examinations after the beginning of insulin therapy. Rats from group II showed significantly greater increases in mean plasma glucose levels at 15 and 30 days after ligature placement compared with rats from group III (p < 0.05). Furthermore, in spite of the significant alveolar bone loss progression that was observed in groups I, II and IV (p < 0.00001; two-way ANOVA), no significant differences among these groups regarding the severity of bone loss (p = 0.77) and no significant interaction between treatment group and time (p = 0.81) were found.Conclusions: Within the limits of this study, it can be suggested that the severity of periodontal disease was not affected by short-term diabetes, and that experimental periodontitis increased blood glucose levels in uncontrolled diabetic rats.

An in vitro evaluation of apicoectomies and retropreparations using different methods

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

Effect of selective cyclooxygenase-2 inhibition on the development of ligature-induced periodontitis in rats

Background: the purpose of this study was to evaluate the effect of a selective cyclooxygenase-2 inhibitor on the progression of alveolar bone loss in an experimental periodontitis model in rats.Methods: One hundred eighty (180) Wistar rats were separated into 3 experimental groups. Cotton ligatures were placed at the gingival margin level of lower right first molars. The rats were randomly assigned to one of the following groups that received: a daily oral dose of 10 mg/kg body weight of celecoxib (Ce1); 20 mg/kg body weight of celecoxib (Ce2); or 10 ml/kg of saline solution (C). Serum levels of celecoxib and white blood cell count were determined. Standardized digital radiographs were taken after sacrifice at 3, 5, 10, 18, and 30 days to measure the amount of bone loss around the mesial root surface of the first molar tooth in each rat.Results: Two-way analysis of variance (ANOVA) indicated that groups treated with celecoxib had significantly less bone loss compared to controls (P <0.0001) and that there was a significant interaction between treatment with celecoxib and time (P <0.03). Post-hoc comparisons showed that in both groups treated with celecoxib, the bone loss became significant only after 10 days of ligature placement, while in the control group it was already significant after 5 days. However, differences in mean bone loss between control and Ce1 were significant only at 18 days and, between control and Ce2, at 5 and 18 days. There was no significant difference in bone loss among experimental groups at the end of the experimental period.Conclusion: These data provide evidence that systemic therapy with celecoxib can modify the progression of experimentally induced periodontitis in rats.

Release and diffusion of hydroxyl ion from calcium hydroxide-based medicaments

The release and diffusion of hydroxyl ions (OH-) of calcium hydroxide (Ca(OH)2)-based intracanal medications may be affected by the association with other substances. The aim of this study was to evaluate the diffusion of OH- ions through root dentin by the medications: G1, Ca(OH)2/saline; G2, Calen; G3, Calen/camphorated p-monochlorophenol (CMCP); and G4, Calen/0.4% chlorhexidine (CHX). Root canals from bovine teeth were prepared in a standardized manner. A cavity until dentin was prepared in the middle third of the root surface of each specimen. The external surface of the root was made impermeable using a layer of adhesive, except the prepared cavity. The root canals were filled with different medications, and teeth were individually stored in flasks containing 10 ml distilled water at 37 degrees C. The water pH was measured at 1, 3, 7, 14, 21, 30, and 60 days. Data obtained were subjected to anova and Tukeys tests. Increase in pH was observed at 3 days for Calen/CHX and from 7 to 14 days for the other mixtures. Calen paste promoted pH increase up to 21 days. Calen/CMCP had the highest pH up to 21 days, and all groups had similar results at 30 days. At 60 days, the greatest pH values were observed for Calen/CMCP and Calen alone. All different formulations of Ca(OH)2-based medications tested release hydroxyl ion that can diffuse through the dentin.

pH changes after manual or ultrasonic instrumentation and smear layer removal with EDTA or ultrasonic

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

Reimplante mediato de dentes tratados ou não com solução de hipoclorito de sódio a 1% - estudo histomorfométrico em ratos

Foi avaliada a influência do hipoclorito de sódio a 1% no reparo do periodonto de incisivos reimplantados tardiamente em ratos. Os dentes foram mantidos em meio ambiente durante 30 minutos e a seguir imersos em hipoclorito de sódio a 1%, por 25 minutos. Os animais foram sacrificados aos 10, 30 ou 60 dias. Os cortes histológicos foram obtidos no sentido transversal dos terços cervical, médio e apical e delineados com um aumento de 52 vezes. Os eventos observados sobre a superfície radicular foram medidos quanto a sua extensão através de um sistema analisador de imagens (Mini-Mop, Carl Zeiss). Aos 10 dias, observou-se a predominância de tecido conjuntivo fibroso no grupo tratado. Aos 30 e 60 dias observou-se o aumento da anquilose e reabsorção por substituição, assim como neoformação limitada de ligamento periodontal. No grupo controle, aos 30 e 60 dias, foram observadas áreas de reabsorções mais extensas e profundas, quando comparadas ao grupo tratado. Os resultados possibilitaram as seguintes conclusões quando comparado o grupo tratado com o controle: a) leva à formação de tecido conjuntivo semelhante a uma cápsula fibrosa no período inicial do reparo; b) possibilita uma limitada neoformação de ligamento periodontal; c) ocasiona uma superfície de anquilose mais extensa; d) não impede a reabsorção por substituição.