Influence of different types of non-resorbable suture material on the healing of extraction wounds--a histological study in rats.

The influence of different non-resorbable suture materials on the healing of tooth extraction wounds was examined in 120 adult male albino rats. Nylon gave the best biological results for healing of the mucosa and dental socket. Silk and cotton produced considerable delay of socket healing. Healing was only mildly delayed by polyester suture, with a short moderate inflammatory reaction at the initial stage.

Interference of the blood clot on granulation tissue formation after tooth extraction. Histomorphological study in rats.

The interference of a blood clot in the first postoperative hours of dental extraction wounds was studied in rats. Sixty male albino rats were divided into two groups: Group I, immediately after extraction of right maxillary incisor the gingival mucosa was approximated and sutured; Group II, after 6 to 8 minutes postoperatively the blood clot was removed with saline irrigation and absorbent paper cones. The mucosa was then approximated and sutured. Six animals in each group were sacrificed after 12 hours, 1, 4, 7 and 10 days. There was a profound delay in healing in Group II since, although a new blood clot was later formed, it was not organized. The quality and the constitution, maintenance and retraction of the clot are the regulating factors in connective tissue formation during alveolar healing.

Evaluation of Paracoccidioides brasiliensis exoantigen in the detection of delayed dermal hypersensitivity in experimental and human paracoccidioidomycosis

The exoantigen of Paracoccidioides brasiliensis standardized by Camargo et al. [1] (AgR) was used to evaluate the in vivo and in vitro cell immune response of experimental animals and of patients with paracoccidioidomycosis (PBM). Fava Netto antigen (AgF) was tested in parallel as a control antigen. The study was conducted with mice and guinea pigs infected with P. brasiliensis or immunized with its fungal antigens, on patients with PBM and on their respective control groups. The cell immune response was analysed by skin tests, and by the macrophage and leucocyte migration inhibition tests (MMIT and LMIT) in the animals and in the patients, respectively. The skin test with AgR as paracoccidioidin was positive in infected or immunized mice and guinea pigs and negative in control animals. The skin tests with AgR (24 h) showed 96.7% positivity in patients with PBM and were negative in control individuals. Histopathological study of the in vivo tests in the different experimental models was consistent with a delayed hypersensitivity response (DHR). Immunohistochemical study of the skin tests of PBM patients demonstrated a predominance of T lymphocytes, confirming the nature of a DHR to the fungal antigens. The in vitro cell immune response showed variable results for the various experimental models, i.e. significant rates of MMIT in immunized mice, a tendency to positivity in infected guinea pigs, and the absence of migration inhibition in PBM patients. Taken together, the data indicate that the AgR is efficient as paracoccidioidin in the evaluation of DHR in PBM, with an optimum time of reading the test of 24 h.

New species of Hemiodus (ostariophysi, characiformes, hemiodontidae) from the Rio Tocantins, Brazil, with comments on color patterns and tooth shapes within the species and genus

A new hemiodontid species, Hemiodus tocantinensis, is described from the rio Tocantins, Amazon basin, Brazil. It is most closely related to H. ternezi and H. thayeria based on the presence of a dark longitudinal stripe extending from behind the eye or the opercle to the tip of lower caudal fin lobe but is distinguished by the possession of 51 to 58 perforated lateral line scales and an oblique dark blotch on the dorsal fin extending from its anterior distal portion through the middle basal portion of the fin. The evolution of color patterns and tooth shapes present in the Hemiodus species is commented.

Effect of whitening agents on dentin bonding

Background: Several studies have shown a reduction in enamel bond strengths when the bonding procedure is carried out immediately after vital bleaching with peroxides. This reduction in bond strengths has become a concern in cosmetic dentistry with the introduction of new in-office and waiting-room bleaching techniques. The aim of this in vitro study was to evaluate the effect of three bleaching regimens: 35% hydrogen peroxide (HP), 35% carbamide peroxide (CP), and 10% CP, on dentin bond strengths. Materials and Methods: One hundred and twenty fresh bovine incisors were used in this study. The labial surface of each tooth was ground flat to expose dentin and was subsequently polished with 600-grit wet silicon carbide paper. The remaining dentin thickness was monitored and kept at an average of 2 mm. The teeth were randomly assigned to four bleaching regimens (n = 30): (A) control, no bleaching treatment; (B) 35% HP for 30 minutes; (C) 35% CP for 30 minutes; and (D) 10% CP for 6 hours. For each group, half of the specimens (n = 15) were bonded with Single Bond/Z100 immediately after the bleaching treatment, whereas the other half was bonded after the specimens were stored for 1 week in artificial saliva at 37°C. The specimens were fractured in shear using an Instron machine. Results: For the groups bonded immediately after bleaching, one-way analysis of variance (ANOVA) followed by the Duncan's post hoc test revealed a statistically significant reduction in bond strengths in a range from 71% to 76%. For the groups bonded at 1 week, one-way ANOVA showed that group B (35% HP for 30 min) resulted in the highest bond strengths, whereas 10% CP resulted in the lowest bond strengths. Student's t-test showed that delayed bonding resulted in a significant increase in bond strengths for groups B (35% HP) and C (35% CP); whereas the group bleached with 10% CP (group D) remained in the same range obtained for immediate bonding. Storage in artificial saliva also affected the control group, reducing its bond strengths to 53% of the original. ©2000 BC Decker Inc.

Organophosphate induced delayed neuropathy in genetically dissimilar chickens: Studies with tri-ortho-cresyl phosphate (TOCP) and trichlorfon

Measurements of plasma cholinesterase (pl.ChE), brain cholinesterase (Br.ChE) and brain Neuropathy Target Esterase (Br.NTE) were made in three different lineages of chickens. All birds received toxicants through gavage in a single oral dose between 08:00 and 09:00 h, after overnight fast. Babcock chickens were treated with 800 mg/kg tri-ortho-cresyl phosphate (TOCP) or 80 mg/kg trichlorfon. The TOCP group had 82% Br.NTE inhibition, when compared to the control group, and no birds displayed symptoms of clinical organophosphate-induced delayed neuropathy (OPIDN). Hy-line w36 lineage chickens were given 1600 mg/kg TOCP and despite this higher dose, Br.NTE inhibition was similar that presented by Babcock chickens. Isabrown chickens were given 1600 mg/kg TOCP or 80 mg/kg trichlorfon. At 36 h all trichlorfon treated birds had from 80 to 90% inhibition of Pl.ChE and Br.ChE, when compared to controls. However, Br.NTE was inhibited less than 20%, and there were no clinical signs of OPIDN. All TOCP treated isabrown chickens had more than 80% Br.NTE inhibition while one of them exhibited just light signs of OPIDN, two chickens became totally paralyzed. This finding suggested that chicken strain was important in the appearance of OPIDN. In addition, 70-80% of NTE inhibition was necessary but was not sufficient to produce OPIDN in chickens, since babcock and hy-line w36 chickens exhibited NTE inhibition in the range of 70-80% without clinical signs of OPIDN. © 2002 Elsevier Science Ireland Ltd. All rights reserved.

Neuroendocrine alterations impair enamel mineralization, tooth eruption and saliva in rats.

Neonatal administration of monosodium glutamate (MSG) in rats causes definite neuroendocrine disturbances which lead to alterations in many organ systems. The possibility that MSG could affect tooth and salivary gland physiology was examined in this paper. Male and female pups were injected subcutaneously with MSG (4 mg/g BW) once a day at the 2nd, 4th, 6th, 8th and 10th day after birth. Control animals were injected with saline, following the same schedule. Lower incisor eruption was determined between the 4th and the 10th postnatal days, and the eruption rate was measured between the 43rd and the 67th days of age. Pilocarpine-stimulated salivary flow was measured at 3 months of age; protein and amylase contents were thereby determined. The animals treated with MSG showed significant reductions in the salivary flow (males, -27%; females, -40%) and in the weight of submandibular glands (about -12%). Body weight reduction was only about 7% for males, and did not vary in females. Saliva of MSG-treated rats had increased concentrations of total proteins and amylase activity. The eruption of lower incisors occurred earlier in MSG-treated rats than in the control group, but on the other hand the eruption rate was significantly slowed down. The incisor microhardness was found to be lower than that of control rats. Our results show that neonatal MSG treatment causes well-defined oral disturbances in adulthood in rats, including salivary flow reduction, which coexisted with unaltered protein synthesis, and disturbances of dental mineralization and eruption. These data support the view that some MSG-sensitive hypothalamic nuclei have an important modulatory effect on the factors which determine caries susceptibility.

Familial malignant osteopetrosis in children: A case report

The clinical, radiological, pathological and laboratory findings of two brothers with autosomal recessive malignant osteopetrosis are presented. Our findings are similar to characteristics previously reported in the literature about patients with osteopetrosis. The 6-year-old male patient was pale and had petechiae on his arms and legs. He also had macrocephalia, splenomegaly, severe pancytopenia, genu valgus, hypocalcemia, amaurosis, cessation of physical development, generalized bone sclerosis and recurrent infections with a history of multiple incidences of acute otitis media. Generalized bone sclerosis and irregular sclerosis of the maxilla and mandible were seen on radiographs. The oral mucosa was apparently normal but permanent tooth eruption was delayed although there was early loss of deciduous teeth. The recommended treatment was blood transfusion and therapy with antibiotics when necessary; a bone marrow transplant was not possible due to lack of a compatible donor.

Periodontal effects of rapid maxillary expansion with tooth-tissue-borne and tooth-borne expanders: A computed tomography evaluation

Introduction: The force delivered during rapid maxillary expansion (RME) produces areas of compression on the periodontal ligament of the supporting teeth. The resulting alveolar bone resorption can lead to unwanted tooth movement in the same direction. The purpose of this study was to evaluate periodontal changes by means of computed tomography after RME with tooth-tissue-borne and tooth-borne expanders. Methods: The sample comprised 8 girls, 11 to 14 years old, with Class I or II malocclusions with unilateral or bilateral posterior crossbites Four girls were treated with tooth-tissue-borne Haas-type expanders, and 4 were treated with tooth-borne Hyrax expanders. The appliances were activated up to the full 7-mm capacity of the expansion screw. Spiral CT scans were taken before expansion and after the 3-month retention period when the expander was removed. One-millimeter thick axial sections were exposed parallel to the palatal plane, comprising the dentoalveolar area and the base of the maxilla up to the inferior third of the nasal cavity. Multiplanar reconstruction was used to measure buccal and lingual bone plate thickness and buccal alveolar bone crest level by means of the computerized method. Results and Conclusions: RME reduced the buccal bone plate thickness of supporting teeth 0.6 to 0.9 mm and increased the lingual bone plate thickness 0.8 to 1.3 mm. The increase in lingual bone plate thickness of the maxillary posterior teeth was greater in the tooth-borne expansion group than in the tooth-tissue-borne group. RME induced bone dehiscences on the anchorage teeth's buccal aspect (7.1 ± 4.6 mm at the first premolars and 3.8 ± 4.4 mm at the mesiobuccal area of the first molars), especially in subjects with thinner buccal bone plates. The tooth-borne expander produced greater reduction of first premolar buccal alveolar bone crest level than did the tooth-tissue-borne expander. © 2006 American Association of Orthodontists.

A new device in immediately loaded implant treatment in the edentulous mandible

Purpose: This article reports preliminary clinical results of the Speed Master system, a method for immediate loading of implants for the treatment of mandibular edentulism. Materials and Methods: Fifteen patients with edentulous mandibles were consecutively included in the study. Each received 4 implants between the mental foramina placed using the system's surgical guides. Permanent fixed prostheses fabricated over premanufactured titanium bars were attached to the implants on the day of implant placement. The patients were followed for 15 to 27 months (mean, 19 months). Peri-implant tissues were periodically evaluated. Marginal bone loss was monitored with periapical radiographs using a computerized technique. Satisfaction was assessed by means of a questionnaire. Results: The overall implant and prosthetic survival rates were 100%. At the time of the final follow-up visit, mean marginal bone loss was 1.11 mm, and bleeding on probing was not observed. Only 6.7% of the patients reported any discomfort during treatment, and all patients would recommend the procedure to others. Discussion: The immediate loading of implants placed in the edentulous mandible with the Speed Master surgical and prosthetic protocol reduces treatment time and number of surgical procedures in comparison to classic delayed loading protocols. Conclusion: The rehabilitation of the mandible with an immediately delivered occlusally loaded hybrid prosthesis supported by 4 implants does not appear to jeopardize the success of the osseointegration and represents a viable treatment option.

Intraosseous schwannoma mimicking a periapical lesion on the adjacent tooth: Case report

Aim: To present an additional case of intraosseous schawannoma involving the apical area in the mandibular alveolar bone mimicking an inflammatory periapical lesion. Summary: This article describes a case of schwannoma periapically located mimicking an inflammatory periapical lesion in the mandible of a 34-year-old female. Diagnostic and therapeutic problems can occur when this lesion is misinterpreted as being endodontic in origin. The diagnosis, radiograph, immunohistochemical aspects and treatment are also discussed. Key learning points: • Intraosseous schwannoma is a rare unilocular radiolucency that when located periapically could be misdiagnosed as an endodontic lesion and result in unnecessary root canal treatment. • The vitality of the pulp is an important test to exclude lesions of inflammatory origin. • Histological examination is important to establish the diagnosis of lesions in the periradicular region. © 2007 International Endodontic Journal.

Bond strength of adhesive systems to human tooth enamel

The purpose of this study was to evaluate in vitro three adhesive systems: a total etching single-component system (G1 Prime & Bond 2.1), a self-etching primer (G2 Clearfil SE Bond), and a self-etching adhesive (G3 One Up Bond F), through shear bond strength to enamel of human teeth, evaluating the type of fracture through stereomicroscopy, following the ISO guidance on adhesive testing. Thirty sound premolars were bisected mesiodistally and the buccal and lingual surfaces were embedded in acrylic resin, polished up to 600-grit sandpapers, and randomly assigned to three experimental groups (n = 20). Composite resin cylinders were added to the tested surfaces. The specimens were kept in distilled water (37°C/24 h), thermocycled for 500 cycles (5°C-55°C) and submitted to shear testing at a crosshead speed of 0.5 mm/min. The type of fracture was analyzed under stereomicroscopy and the data were submitted to Anova, Tukey and Chi-squared (5%) statistical analyses. The mean adhesive strengths were G1: 18.13 ± 6.49 MPa, (55% of resin cohesive fractures); G2: 17.12 ± 5.80 MPa (90% of adhesive fractures); and G3: 10.47 ± 3.14 MPa (85% of adhesive fractures). In terms of bond strength, there were no significant differences between G1 and G2, and G3 was significantly different from the other groups. G1 presented a different type of fracture from that of G2 and G3. In conclusion, although the total etching and self-etching systems presented similar shear bond strength values, the types of fracture presented by them were different, which can have clinical implications.