Effect of Nd:YAG Irradiation and Fluoride Application on Dentine Resistance to Erosion in Vitro

Objective: In this paper we evaluated the effect of two fluoridated agents and Nd:YAG irradiation separately and in combination on dentine resistance to erosion. Background Data: The morphological changes in dentin induced by laser treatment may reduce the progression of erosive lesions. Due to the possibility of a synergistic effect of laser with fluoride, this study was conducted. Materials and Methods: Eighty bovine dentine samples (4 x 4 mm) were randomly divided into eight groups, according to the following treatments: G1: untreated (control); G2: acidic phosphate fluoride gel (APF 1.23%) for 4 min; G3: fluoride varnish (NaF 2.26%) for 6 h; G4: 0.5 W Nd: YAG laser (250 mu sec pulse, 10 Hz, 35 J/cm(2), 30 sec); G5: 0.75 W Nd: YAG laser (52.5 J/cm(2)); G6: 1.0 W Nd: YAG laser (70 J/cm(2)); G7: APF + 0.75 W Nd: YAG laser; and G8: NaF + 0.75 W Nd: YAG laser. After the treatments, half of each dentine surface was protected with nail varnish. The samples were stored in artificial saliva (30 mL/sample) for 24 h and submitted to four erosive 1-min cycles. Between the erosive attacks, the blocks were maintained in artificial saliva for 59 min. The erosive wear was evaluated by profilometry. Results: The mean wear (+/- SD, mu m) was: G1: 1.20 +/- 0.20; G2: 0.47 +/- 0.06; G3: 0.81 +/- 0.11; G4: 1.47 +/- 0.32; G5: 1.52 +/- 0.24; G6: 1.49 +/- 0.30; G7: 0.49 +/- 0.11; and G8: 1.06 +/- 0.31 (Tukey's test, p < 0.05). Conclusions: Laser irradiation was not able to reduce dentine erosion. However, fluoride application was able to increase the dentine's resistance to erosion, and APF showed better results than fluoride varnish.

Root surface treatment with vitamin C in tooth replantation: microscopic study in rats

AIM: Late tooth replantation is a worthy procedure, especially in growing patients, being the best option for tooth avulsion. This study evaluated the effects of root surface treatment with 2% acidulated phosphate sodium fluoride and effervescent vitamin C (Redoxon) in late replantation. METHODS: Twenty rat teeth (Rattus norvegicus, albinus, Wistar) were extracted and left on a table for 6 h. Then, the dental papilla and enamel organ were sectioned and the pulp was removed through the apex. After removal of the periodontal ligament with a blade, the animals were divided into 2 groups: Group I teeth were immersed in 2% acidulated phosphate sodium fluoride solution for 10 min and obturated with Ca(OH)(2) paste. Group II teeth were immersed in effervescent vitamin C solution (Redoxon 2 g) for 10 min and obturated as for Group I. After these procedures, teeth were replanted and animals were killed after 60 days. RESULTS: The study revealed a larger amount of replacement resorption in Group I and larger amount of ankylosis in Group II, with statistically significant difference and absence of inflammatory resorption. CONCLUSION: The substances used for root surface treatment were unable to prevent replacement resorption and ankylosis, which are expected when the periodontal ligament has been lost.

Expression of opg, rank, and rankl proteins in tooth repair processes after immediate and delayed tooth

This study evaluated the immunohistochemical expression of OPG, RANK, and RANKL proteins in the repair after immediate and delayed replantation of rat teeth. Fifty-six Wistar rats (Rattus norvegicus albinus) had their maxillary right lateral incisor extracted and then replanted, according to the following conditions: group I (control; n = 8), teeth were not extracted; group II (n = 16), immediate replantation; group III (n = 16), delayed replantation without treatment; and group IV (n = 16), delayed replantation after root surface treatment (periodontal ligament removal and immersion in 2% acidulated-phosphate sodium fluoride) and calcium hydroxide intracanal dressing. Rats in group I were euthanized on the first day of the experiment, while the animals in the other groups were euthanized 10 and 60 days after replantation (n = 8/period). Hematoxylin and eosin-stained sections were obtained for histological analysis. The immunohistochemical analysis revealed expression of OPG and RANKL proteins in all groups and both postreplantation times, except for group II at 60 days. In the experimental groups, RANK expression was observed only at 10 days. In conclusion, there was strong immunostaining for the OPG-RANK-RANKL system at the earlier postreplantation time, suggesting a more effective participation of these proteins at the start of the healing process, as their expression decreased at 60 days. Copyright © 2013 by Mutaz B. Habal, MD.

Efeito do tratamento da superfície radicular com própole ou com flúor no reimplante tardio de dentes de ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da antibioticoterapia sistêmica com Amoxicilina ou Tetraciclina no reimplante dentário tardio em ratos

Pós-graduação em Odontologia - FOA

Imunomarcação das proteínas OPG, RANK e RANKL em dentes reimplantados de rato

Pós-graduação em Odontologia - FOA

Delayed tooth replantation: MTA as root canal filling

MTA has been investigated as a root-end filling material. Its mechanism of action has some similarities to that of Ca(OH())2. The purpose of this study was to evaluate the repair process taking place in the delayed replantation of monkey teeth using calcium hydroxide and MTA as root canal filling materials. Five monkeys had their lateral incisors extracted and bench-dried for 60 minutes. After root canal preparation, the teeth were assigned to two groups according to root canal filling material: I, calcium hydroxide; and II, MTA. The same treatment sequence was followed for both groups: coronal seal, periodontal ligament removal, immersion of the tooth in 2% acidulated-phosphate sodium fluoride, irrigation of the socket with saline and replantation. Both groups exhibited replacement resorption, areas of ankylosis and absence of inflammatory root resorption. Statistically similar results (p > 0.05) were observed for both groups regarding replacement root resorption, but the groups differed significantly (p < 0.05) regarding the occurrence of ankylosis. MTA may be a viable clinical option for filling teeth submitted to delayed replantation, and is an acceptable option for treating replanted permanent teeth in order to prevent tooth resorption, particularly when dressing changes are not possible.

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)

Efeitos de fontes de fósforo e da calagem na produção de amendoim

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Programas preventivos basados en fluoruros en preescolares de riesgo social con altos índices de caries

En Mendoza se realizó un estudio clínico de intervención, prospectivo de dos años, dirigido a preescolares en riesgo social con alto índice de caries con el objetivo de evaluar la eficacia y efectividad de un programa preventivo basado en fluoruros. El programa preventivo se basó en acciones de educación para la salud, enseñanza de técnicas de higiene bucal y aplicación tópica de flúor fosfato acidulado realizadas dos veces durante el ciclo escolar. La muestra intencionada sumó 96 niños de sala de 4 años (2009) que fueron evaluados en su cursado posterior en sala de 5 años (2010) y en 1er año de EGB durante 2011. Niños asistentes a sala de 5 años y primer año EGB al momento del examen basal (2009) conformaron el grupo control. Se les aplicó el mismo programa por razones éticas. A 12 y 24 meses de aplicado el programa se evaluó: porcentaje de libres de caries, ceod+CPOD, cpos+CPOS y sus valores discriminados, medias de categorías ICDAS II, índice de Placa Bacteriana de Löe y Silness e índice de necesidad de tratamiento de caries de Bordoni. Se determinó la distribución de frecuencias e intervalos de confianza para cada variable; medidas de tendencia central y dispersión y se realizaron comparaciones entre grupos mediante la prueba T de Student y chi cuadrado con un nivel de p=0.05. Resultados: Comparando sala 5 años 2010 / sala de 5 años 2009: disminuyeron significativamente las medias de ceod +CPOD, ICDAS 6, Índice Placa Löe e índice de necesidad de tratamiento. Comparando 1er año 2011 / 1er año 2009: disminuyeron significativamente las medias de cs+CS, ceos+CPOS e ICDAS 4. El resto de los valores no mostró diferencias significativas. Conclusión: Un programa preventivo basado en fluoruros es efectivo y tiene efectos positivos sobre la prevalencia de caries en preescolares de Mendoza.

In situ evaluation of the remineralizing capacity of pit and fissure sealants containing amorphous calcium phosphate and/or fluoride

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biochemical and microbiological characteristics of in situ biofilm formed on materials containing fluoride or amorphous calcium phosphate

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

A vibrational spectroscopic study of a hydrated hydroxy-phosphate mineral fluellite, Al2(PO4)F2(OH)·7H2O

Raman and infrared spectra of two well-defined fluellite samples, Al2(PO4)F2(OH)�7H2O, from the Krásno near Horní Slavkov (Czech Republic) and Kapunda, South Australia (Australia) were studied and tentatively interpreted. Observed bands were assigned to the stretching and bending vibrations of phosphate tetrahedra, aluminum oxide/hydroxide/fluoride octahedra, water molecules and hydroxyl ions. Approximate O–H���O hydrogen bond lengths were inferred from the Raman and infrared spectra.

Interaction of aqueous inorganic orthophosphate and phosphate rock

An experimental study was made of the interaction of phosphate rock and aqueous inorganic orthophosphate, calcium, and hydroxyl ions. A model of the reaction was developed by observing electron diffraction patterns in conjunction with concentration changes of chemical components. The model was applied in explaining the performance of batch suspensions of powdered phosphate rock and packed columns of granular phosphate rock. In both cases the reaction consisted initially of a rapid nucleation phase that occurred in a time period of minutes. In the batch system the calcium phosphate nuclei then ripened into larger micro-crystals of hydroxyapatite, which eventually became indistinguishable from the original phosphate rock surface. During column operation the high supersaturation ratio that existed after the rapid nucleation phase resulted in a layer of small nuclei that covered a slowly growing hydroxyapatite crystal.

The column steady-state rate constant was found to increase with increasing temperature, pH, and fluoride concentration, and to decrease with increasing concentrations of magnesium sulfate, ammonium chloride, and bicarbonate ion.

An engineering feasibility study indicated that, based on economic considerations, nucleation of apatite on phosphate rock ore has a potential use as a wastewater phosphate removal treatment process.

Structural role of fluoride in aluminophosphate sol-gel glasses: High-resolution double-resonance NMR studies

The local structure of Na-Al-P-O-F glasses, prepared by a novel sol-gel route, was extensively investigated by advanced solid-state NMR techniques. Al-21{F-19} rotational echo double resonance (REDOR) results indicate that the F incorporated into aluminophosphate glass is preferentially bonded to octahedral Al units and results in a significant increase in the concentration of six-coordinated aluminum. The extent of Al-F and Al-O-P connectivities are quantified consistently by analyzing Al-27{P-31} and Al-21{F-19} REDOR NMR data. Two distinct types of fluorine species were identified and characterized by various F-19{Al-27}, F-19{Na-23}, and F-19{P-31} double resonance experiments, which were able to support peak assignments to bridging (Al-F-Al, -140 ppm) and terminal (Al-F, -170 ppm) units. On the basis of the detailed quantitative dipole-dipole coupling information obtained, a comprehensive structural model for these glasses is presented, detailing the structural speciation as a function of composition.