Delayed tooth replantation following root canal filling with calcium hydroxide and MTA: Histomorphometric study in rats

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

Apoptosis and reduced microvascular density of the lamina propria during tooth eruption in rats

During tooth eruption, structural and functional changes must occur in the lamina propria to establish the eruptive pathway. In this study, we evaluate the structural changes that occur during lamina propria degradation and focus these efforts on apoptosis and microvascular density. Fragments of maxilla containing the first molars from 9-, 11-, 13- and 16-day-old rats were fixed, decalcified and embedded in paraffin. The immunohistochemical detection of vascular endothelial growth factor (VEGF), caspase-3 and MAC387 (macrophage marker), and the TUNEL method were applied to the histological molar sections. The numerical density of TUNEL-positive cells and VEGF-positive blood vessel profiles were also obtained. Data were statistically evaluated using a one-way anova with the post-hoc Kruskal-Wallis or Tukey test and a significance level of P ≤ 0.05. Fragments of maxilla were embedded in Araldite for analysis under transmission electron microscopy (TEM). TUNEL-positive structures, fibroblasts with strongly basophilic nuclei and macrophages were observed in the lamina propria at all ages. Using TEM, we identified processes of fibroblasts or macrophages surrounding partially apoptotic cells. We found a high number of apoptotic cells in 11-, 13- and 16-day-old rats. We observed VEGF-positive blood vessel profiles at all ages, but a significant decrease in the numerical density was found in 13- and 16-day-old rats compared with 9-day-old rats. Therefore, the establishment of the eruptive pathway during the mucosal penetration stage depends on cell death by apoptosis, the phagocytic activity of fibroblasts and macrophages, and a decrease in the microvasculature due to vascular cell death. These data point to the importance of vascular rearrangement and vascular neoformation during tooth eruption and the development of oral mucosa.

Immediate tooth replantation in rats: effect of systemic antibiotic therapy with amoxicillin and tetracycline

The aim of this study was to evaluate the influence of systemic administration of antibiotics (amoxicillin and tetracycline) at the different phases of the repair process (7, 15, 30 days) in immediate rat tooth replantation. Ninety rats had their incisors extracted and stored in saline for 5 min. Next, the teeth were replanted, and the animals were assigned to three groups according to the antibiotic administered by oral gavage: control group, amoxycillin group, and tetracycline group. Euthanasia was performed at 7, 15, and 30 days after replantation. Regardless of the evaluation period, the connective tissue underlying the epithelial attachment and the periodontal ligament showed statistically significant difference relative to the acute inflammatory infiltrate, which was more intense in the control group followed by the tetracycline group. These results point to the fact that systemic antibiotic therapy (SAT) in immediate tooth replantation is beneficial to pulpal and periodontal ligament repair and that amoxycillin is an excellent option. There is a lack of randomized studies assessing how the use of systemic antibiotics could influence tooth healing after immediate replantation.

Delayed tooth replantation in rats: effect of systemic antibiotic therapy with amoxicillin and tetracycline

Systemic antibiotic therapy (SAT) has usually been recommended after tooth replantation, but its actual value has been questioned. As there are no reports in the literature about its influence on tooth replantation, the aim of this study was to evaluate the influence of systemic administration of antibiotics (amoxicillin and tetracycline) at the different phases of the repair process (7, 15, 30 days) in delayed rat tooth replantation. Ninety Wistar rats (Rattus norvegicus albinus) had their maxillary right incisors extracted and bench-dried for 60 min. The dental papilla, enamel organ, pulp tissue, and root surface-adhered periodontal ligament were removed, and the teeth were replanted. The animals received no antibiotics (n = 30) or were medicated systemically with amoxicillin (n = 30) and tetracycline (n = 30), and were euthanized after 7, 15, and 30 days. Regardless of the evaluation period, the acute inflammatory infiltrate was less intense and root resorption presented smaller extent and depth in the group treated with amoxicillin. The results suggest that SAT has a positive influence on the repair process in delayed tooth replantation and that amoxicillin is an excellent treatment option.

Analysis of the biomechanical behavior of short implants: the photo-elasticity method

The aim of this study was to analyze the stress distribution of short implants supporting single unit or splinted crowns by the photo-elasticity method. Four photo-elastic models were produced: A (3.75×7mm); B (3.75×7mm, 3.75×7mm and 3.75×7mm); C (3.75×10mm, 3.75×7mm and 3.75×7mm); D (3.75×13mm, 3.75×7mm and 3.75×7mm). The prostheses were made with Ni-Cr alloy. A load of 100N in the axial and oblique directions was applied, totaling 380 applications, individually capturing their images in each model. The data were randomized and analyzed qualitatively and quantitatively by 2 examiners. The oblique loading was significantly more damaging. The increase in length was favorable for stress distribution (p<0.05). The splinting was beneficial for the transmission of stresses mainly (p<0.05). The splinting of the crowns, as well as increasing the length of the first implant and axial loading was most beneficial in the stress distribution. Short splinted implants behaved better than single unit implants. Increasing of the length of the first implant significantly improved the stress distribution in all analyzed situations.

Structural study of copper oxide supported on a ceria-modified titania catalyst system

A structural study of CuO supported on a CeO2-TiO2 system was undertaken using X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) techniques. The results of XRD revealed the presence of only two phases, TiO2 anatase and CeO2 cerianite. A trend towards smaller TiO2 crystallites was observed when cerium content increased. When the amount of cerium increased, Ti K-edge XANES analysis showed an increasing distortion of Ti sites. The results of Ce LIII-edge EXAFS showed that Ce atoms are coordinated by eight oxygen atoms at 2.32 Å. For the sample containing a small amount of cerium, the EXAFS analysis indicated that the local structure around Ce atoms was highly distorted. The catalysts presented quite different Cu K-edge XANES spectra compared to the spectra of the CuO and Cu2O reference compounds. The Cu-O mean bond length was close to that of the CuO and the Cu atoms in the catalysts are surrounded by approximately four oxygen atoms in their first shell. Copper supported on the ceria-modified titania support catalysts displayed a better performance in the methanol dehydrogenation when compared to copper supported only on titania or on ceria. © 2002 Plenum Publishing Corporation.

Delayed tooth replantation after treatment of necrotic periodontal ligament with citric acid

Objective: to evaluated the effect of treating root-adhered necrotic periodontal ligament (PDL) with citric acid on the healing process in delayed rat tooth replantation. Material and Methods: Forty Wistar rats, assigned to 4 groups (n=10), had their upper right incisor extracted and kept dry on a workbench. For Group I (control), the teeth were replanted after a 5 min extra-alveolar time. For the other groups, replantation was hydroxide-based paste and the teeth were replanted with no root surface treatment. In Group III, the teeth were immersed in citric acid (pH 1) for replanted. In Group IV, instead of the immersion, the roots were scrubbed with gauze soaked in citric acid and the teeth were replanted. The animals difference (p > 0.05) was found among the groups regarding the areas difference (p < 0.05) between the control group and Group IV regarding ankylosis. The control group showed the least replacement resorption percent means compared to the other groups (p < 0.05). The root structure was more affected by replacement resorption and ankylosis in Group IV statistically (p > 0.05). Conclusion: the treatment of root surface-adhered necrotic periodontal ligament with citric acid was not able to prevent the delayed rat tooth replantation.

Delayed tooth repalantetion after treatment of necrotic periodontal ligament with citric acid

Objective: to evaluated the effect of treating root-adhered necrotic periodontal ligament (PDL) with citric acid on the healing process in delayed rat tooth replantation. Material and Methods: Forty Wistar rats, assigned to 4 groups (n=10), had their upper right incisor extracted and kept dry on a workbench. For Group I (control), the teeth were replanted after a 5 min extra-alveolar time. For the other groups, replantation was done after 60 min. In Group II, the root canals were filled with a calcium hydroxide-based paste and the teeth were replanted with no root surface treatment. In Group III, the teeth were immersed in citric acid (pH 1) for 3 min, the canals were filled with calcium hydroxide and the teeth were replanted. In Group IV, instead of the immersion, the roots were scrubbed with gauze soaked in citric acid and the teeth were replanted. The animals were sacrificed 60 days postoperatively. Results: Regarding replacement resorption, there was statistically significant difference (p < 0.05) between the control group and the other three groups. No statistically significant difference (p > 0.05) was found among the groups regarding the areas of inflammatory resorption. There was also a statistically significant difference (p < 0.05) between the control group and Group IV regarding ankylosis. The control group showed the least replacement resorption percent means compared to the other groups (p < 0.05). The root structure was more affected by replacement resorption and ankylosis in Group IV compared to the Groups II and III, but this difference was not significant statistically (p > 0.05). Conclusion: the treatment of root surface-adhered necrotic periodontal ligament with citric acid was not able to prevent the occurrence of ankylosis, root resorption and inflammatory resorption in delayed rat tooth replantation.

Enxerto de tecido conjuntivo para correção da margem peri-implantar

Soft tissue recessions frequently cause esthetic disharmony and dissatisfaction. The results of coverage in peri-implant sites, in comparison with soft tissue coverage around a tooth, is less predictable. This clinical report describes the correction of an esthetic problem with a single-tooth implant-supported using a subepithelial connective tissue graft (SCTG) combined with the re-establishment of a new limit of gingival margin, and emergence crown profile. After anamnese and clinical exam it was observed an implant in the region of tooth 22 in vestibular position to alveolar ridge with a recession of 5 mm in its vestibular face. In the first cirurgical procedure the crown and the abutment were removed and a SCTG associated with a coronally positioned flap was performed in order to re-establish the limit of gingival margin. After 90 days, it was observed that the tissue in the implant site showed no adequate volume or thickness. Because of that, another SCTG was performed. The reopening procedure to install the healing cap was performed after 4 weeks. Then the prosthesis was installed. At 180 and 360 days postoperative, the implant adjacent tissue presented regular contour, color compatible with health and absence of bleeding. The patient was satisfied with the esthetic result. According to the clinical results and favorable esthetics it was possible to conclude that the use of ETC to correct an esthetic deficiency may be a feasible approach to establish new and stable peri-implant soft tissue contours.

Análise por computação gráfica das alterações produzidas em próteses totais superiores imersas diretamente em água e pela termociclagem

Objectives: This study aimed to assess dimensional changes in acrylic resin base and artificial teeth position after water storage and thermocycling using computer graphics measurements. Methods: Twenty-four waxed replicas were obtained from a previous upper complete denture. For linear measurements, points in cusps tips of left central incisor and second premolars and molars were marked in one of the prostheses with graphite and transferred to the others using an acrylic resin guide. The prostheses were scanned after waxing, polymerization and treatments and the images were exported to “AutoCad 2002 Today®” software for measurements. Results: There was no statistically significant difference in changes of each segment for each group and between the phases evaluated after polymerization and thermocycling. In groups I and III, the values after polymerization are higher than those after treatment, which suggests shrinkage while the prostheses in group II have expanded. Conclusion: The three groups exhibited artificial teeth movement after tests in comparison to the polymerized prosthesis. The prostheses submitted to water storage in kiln at 36ºC during seven days showed different behavior than the other groups.

Aspectos clínicos influentes no planejamento das próteses sobre implantes tipo overdenture e protocolo

The aim of his study was to review the current scientific literature in order to discuss the surgical, prosthetics and psychological/psychosocial aspects during the treatment planning of edentulous patients, when a total fixed prosthesis or overdenture is indicated. To identify studies to take part in this review, a search was conducted for the following databases: PubMed, Dentistry and Oral Sciences Source, Journals@Ovid, SpringerLink, Wiley Online Library, Nature (NPG), Oxford Journals. It was used as descriptors: total fixed prostheses and overdentures. Inclusion criteria were: clinical articles, clinical case reports, case series, literature reviews and systematic reviews that addressed the study and comparison of total fixed prostheses and overdentures for a surgical- prosthetic planning. Exclusion criteria were: laboratory and in vitro studies and those whose first language was not English or Portuguese. Of a total of 454 articles, after an analysis according to inclusion and exclusion criteria, 76 articles were selected. During an implantsupported prosthesis rehabilitation with dental in edentulous patients, the use of alternative procedures appear to be effective when compared to more invasive surgical techniques, and thus, the amount of dental implants possible to install associated with prosthetic issues such as lip support, smile line, quantity and quality of mucosa, phonetics, etc., will allow an appropriate treatment planning to each clinical case

Planejamento reverso em implantodontia: relato de caso clínico

The oral rehabilitation has achieved great prominence in the dental implant, especially in the cases of reposition of units dental elements, so it is possible to replace each missing element to implant into your space where the tooth was loss. The reverse planning is fundamental to an appropriate rehabilitation, because promote the elimination of problems that might compromise the aesthetics and function of future dental implants. The objective of this study was to report the treatment plan for a patient in need of oral rehabilitation with implant dental prosthesis, using indications and techniques based on the literature, emphasizing the importance of reverse planning. We conducted an osseointegrated implant surgery using the principles of a connect procedure, thus allowing their successfully installing increasing the predictability of treatment. It is concluded that the success of rehabilitation treatment is directly related to the initial planning, a correct clinical approach and an integrated multidisciplinary team.

Uso de sistema de retenção magnético como opção de tratamento para solução de caso com espaço interoclusal reduzido

The treatment with overdenture supported by tooth consists in complete or partial removable prosthesis confection in which some satisfactory tooth are maintained and used to aiding retention associated with any retention system. The purpose of this case report is to show the use of magnet attachment in the confection overdenture to improve the oral rehabilitation in cases with restricted intermaxillary space. The treatment was considered successful by the patient and no need for excessive alteration in the prosthesis was required in the follow-up period of 6 months.

Prótese total fixa na maxila: soluções protéticas

The modalities of treatment with prostheses over implants for total edentulous patients can be divided in fixed and removable prostheses (overdentures). The fixed prostheses modality has proven to offer better results as to the functional aspects and, results in higher longevity. Overdentures are considered as a modality of rehabilitation utilized to compensate the need for better retention, aside from augmenting chewing efficiency. Its use is justified by its facilitated hygiene, reduced surgical and prosthetic costs, reestablishment of labial support and elimination of the possibility of air escape. However, this option presents psychosocial downside, since the fact that it is considered a removable rehabilitation modality does not please the majority of patients. Although many patients prefer a fixed implant-supported prosthesis to a removable overdenture, frequently it is necessary to utilize an implant retained overdenture as an alternative to the treatment, due to anatomical, physiological, aesthetic, hygienic, and financial limitations regarding the patient. The objective of this study was to discuss a clinical case of a partially edentulous patient treated in the Implantodontic Surgery Post-Graduation Course from the Kenedy Dentistry Institute Mozarteum/Famosp Unit – Goiânia-Brazil), and submitted to osseointegrated implants surgical fixation techniques. A modality of differential diagnosis was established after osseointegration period, it aimed at facilitating the choice of a rehabilitation model that could favor the patient’s and professional`s expectations. Therefore the appreciated aspects were function, comfort, aesthetics, and especially the patient satisfaction.

Distal extension removable partial denture with resilient attachment connect to an anterior fixed implant-supported prosthesis: a clinical report

Background: Considering the limited qualitative and quantitative bone in the posterior arch, this modality of prosthetic treatment could provide a positive emotional factor reestablished by immovability of the anterior fixed implant-supported segment. Objective: This clinical report demonstrates the possibility of achieving positive results with a removable partial denture connected to an implant-supported fixed prosthesis associated to an extra resilient attachment. Clinical significance: In cases of posterior mandibular and maxilla atrophy added to the patients desire against the bone graft, this kind of prosthetic treatment has an important place as an alternative.