Bonding properties of universal adhesives to root canals prepared with different rotary instruments

Statement of problem

Preparation of coronal dentin by using a diamond rotary instrument usually results in higher bond strength values than preparation with tungsten carbide burs, but information is lacking about the influence of rotary instruments on root canals before the bonding of fiber posts.

Esthetic alternative for fluorosis blemishes with the usage of a dual bleaching system based on hydrogen peroxide at 35%

Esthetic dental procedures in pediatric dentistry represent sources of satisfaction and realization, as much for the patient as for the professional. Lack of dental esthetics may develop psychological problems in infant as well as in adolescent patients. Blemishes produced by fluorosis appear as a challenge to the pediatric dentist and alternatives for treatment are desired. The scope of this present paper is to relate a clinical case with esthetic solution for blemishes in teeth enamel due to fluorosis. A dual system of bleaching was used (photo/chemically activated) based on hydrogen peroxide at 35% (Hi-Lite-Shofu) in a male eight-year-old patient with white fluorosis blemishes on teeth 11 and 21. The bleaching system used was efficient in bleaching teeth with white blemishes due to fluorosis, thus masking the blemishes and providing a more uniform appearance.     

Proliferative activity in oral salivary gland tumors: the role of PCNA and AgNOR assessed by a double staining technique

The aim of this study was to evaluate the role of PCNA and AgNOR in the assessment of salivary gland tumor proliferation using a double staining technique. Ten cases of pleomorphic adenoma (PA) and seventeen cases of adenoid cystic carcinoma (ACC) were examined. Numeric and morphometric parameters of AgNOR were evaluated and compared in PCNA-positive and PCNA-negative nuclei. There were statistically significant differences in AgNOR numbers, perimeters and contour indices between PCNA-positive and -negative nuclei in the PA samples. The ACC samples demonstrated significant differences only in the AgNOR areas. Our results show that in salivary gland tumors there is not always a relationship between proliferative activity evaluated by AgNOR numeric and morphometric parameters and PCNA immunostaining.     

Histomorphometric evaluation of the effect of bovine collagen granules on bone healing. An experimental study in rats

Collagen materials have been utilized in medicine and dentistry because of their proven biocompatibility and capability of promoting wound healing. The aim of the present experimental study was to perform a histomorphometric evaluation of the effect of bovine collagen granules on post-extraction alveolar wound healing in rats. Twenty male Wistar rats were submitted to bilateral extraction of the first lower molars under ketamine/xylazine anesthesia according to the technique previously described by Guglielmotti and Cabrini. Sterile Bovine collagen granules of approximately 80 +/- 10 microm (Membracel G, Lab. Celina, Buenos Aires) were hydrated with saline solution and placed into the right mesial socket (experimental side) with gentle pressure, completely filling the site. The contralateral sockets were considered as the control side. Sutures were not performed. After surgery neither special diet nor antibiotics were given. The rats were fed rat chow and water ad libitum. All the animals were killed on the 30th day following surgery by ether overdose. The jaws were dissected, radiographed, decalcified, and embedded in paraffin. Sections were obtained at the level of the first molar mesial socket in a buccolingual orientation and stained with hematoxylin-eosin. The trabecular area and volume density of trabecular bone were measured histomorphometrically. The trabecular area was greater in alveoli treated with collagen granules than in control alveoli (P<0.05). Values of volume density of trabecular bone were greater in experimental than in control sockets (P<0.05). This experimental study provides evidence for the use of bovine collagen granules as bone grafting material, as a therapeutic alternative to fill postextraction sockets.     

Impact of oral health on quality of life among the elderly population of Joaçaba, Santa Catarina, Brazil

The objective of this study was to investigate the impact of oral health conditions on the quality of life of elderly people in Joa?aba - SC, in Southern Brazil. A survey based on systematic sampling of clusters was carried out with 183 elderly people that belong to old age groups. The survey was conducted in order to assess the oral conditions of the participants (use of and need for prosthesis) based on the criteria from the World Health Organization publication "Oral Health Surveys, Basic Methods", 4th edition. The oral health impact profile (OHIP) was used to evaluate the impact of oral condition in the quality of life. ABIPEME (Brazilian Association of Market Research Institutes) criterion was used, together with the level of education and the number of people in the household to determine social inequalities. The participants were mostly women (82%) and the OHIP mean was 10.35. No correlation was observed between the OHIP level and formal education or between OHIP and number of residents per household. There was a correlation of 0.240 (p = 0.001) between ABIPEME and OHIP. The OHIP mean for those not using maxillary prosthesis was 12.48 and the mean for those using it was 9.81 (p = 0.399). The mean OHIP for those in need of maxillary prosthesis for those who did not need it was 13.00 and 8.88, respectively (p = 0.014). The same trend was found for the use and need for mandibular prosthesis. The conclusion was that the need for maxillary and mandibular prosthesis impacted the quality of life among the elderly population of Joa?aba.     

Three-dimensional reconstruction studies and morphometric analysis of rudimental tooth primordia in the upper incisor region of the sheep (Ovis aries,Ruminantia)

The functional dentition of the domestic sheep lacks all upper incisors and the upper canines. Nevertheless, occurrence of a dental lamina and rudimental tooth primordia had been described in the upper incisor region of the sheep. The aim of this study was to describe temporo-spatial pattern of origin and regression of these rudimental tooth primordia by light microscopy, computer-aided three-dimensional reconstruction and morphometry of the dental epithelium. Transient existence of a dental lamina in the upper incisor region of the sheep and three epithelial thickenings on its deep mesenchymal margin has been observed at day of ontogeny (DO) 48-53. They could not been identified as full-value tooth primordia, because they did not induce differentiation of tooth mesenchyme, but they could represent last remnants of functional upper incisors in early ancestors of ruminants. Additionally, a large rudimental upper canine primordium near the sutura maxilloincisiva occurred at DO43, reached early cap stage at DO52 and started to regress at DO53. Thus, our findings showed a discrepancy between the embryonic and adult dental pattern in the sheep. Similar molecular mechanisms as described for diastemal tooth rudiments in rodents could be involved during regression of rudimental tooth primordia in the upper incisor region of the sheep.     

Biodistribution of a carborane-containing porphyrin as a targeting agent for Boron Neutron Capture Therapy of oral cancer in the hamster cheek pouch

Boron Neutron Capture Therapy (BNCT) is a bimodal cancer treatment based on the selective accumulation of 10B in tumors and concurrent irradiation with thermalized neutrons. The short-range, high-LET radiation produced by the capture of neutrons by 10B could potentially control tumor while sparing normal tissue if the boron compound targets tumor selectively within the treatment volume. In previous studies, we proposed and validated the hamster cheek pouch model of oral cancer for BNCT studies, proved that absolute and relative uptake of the clinically employed boron compound boronophenylalanine (BPA) would be potentially therapeutic in this model and provided evidence of the efficacy of in vivo BPA-mediated BNCT to control hamster oral mucosa tumors with virtually no damage to normal tissue. We herein present the biodistribution and pharmacokinetics of a lipophilic, carborane-containing tetraphenylporphyrin (CuTCPH) in the hamster oral cancer model. CuTCPH is a novel, non-toxic compound that may be advantageous in terms of selective and absolute delivery of boron to tumor tissues. For potentially effective BNCT, tumor boron concentrations from a new agent should be greater than 30 ppm and tumor/blood and tumor/normal tissue boron concentration ratios should be greater than 5/1 without causing significant toxicity. We administered CuTCPH intraperitoneally (i.p.) as a single dose of 32 microg/g body weight (b.w.) (10 microg B/g b.w.) or as four doses of 32 microg/g b.w. over 2 days. Blood (Bl) and tissues were sampled at 3, 6, 12, 24, 48, and 72 h in the single-dose protocol and at 1-4 days after the last injection in the multidose protocol. The tissues sampled were tumor (T), precancerous tissue surrounding tumor, normal pouch (N), skin, tongue, cheek and palate mucosa, liver, spleen, parotid gland and brain. The maximum mean B ratios for the single-dose protocol were T/N: 9.2/1 (12h) and T/Bl: 18.1/1 (72 h). The B value peaked to 20.7+/-18.5 ppm in tumor at 24h. The multidose protocol maximum mean ratios were T/N: 11.9/1 (3 days) and T/Bl: 235/1 (4 days). Absolute boron concentration in tumor reached a maximum value of 116 ppm and a mean value of 71.5+/-48.3 ppm at 3 days. The fact that absolute and relative B values markedly exceeded the BNCT therapeutic threshold with no apparent toxicity may confer on this compound a therapeutic advantage. CuTCPH-mediated BNCT would be potentially useful for the treatment of oral cancer in an experimental model.     

Eruption of teeth associated with a dentigerous cyst by only marsupialization treatment: a case report

The purpose of this case report was to describe the management of a mandibular dentigerous cyst in a 10-year-old male patient. Without any clinical symptom, the lesion was detected in a routine panoramic radiograph showing a well-defined osteolytic lesion that measured 3 cm in diameter, partially surrounding the crown of the canine, first molar, and second premolar displacing the teeth to the mandible's lower border. The apex of the teeth were still open. Under local anesthesia, the patient was treated by: extraction of the left deciduous canine and first and second deciduous molars; and marsupialization of the cystic cavity. After 30 months, the premolar had erupted and an orthodontic therapy was started to maintain space for the canine.