Direct comparison of the bond strength results of the different test methods: A critical literature review

Objective. The goal of this paper is to undertake a literature search collecting all dentin bond strength data obtained for six adhesives with four tests ( shear, microshear, tensile and microtensile) and to critically analyze the results with respect to average bond strength, coefficient of variation, mode of failure and product ranking. Method. A PubMed search was carried out for the years between 1998 and 2009 identifying publications on bond strength measurements of resin composite to dentin using four tests: shear, tensile, microshear and microtensile. The six adhesive resins were selected covering three step systems ( OptiBond FL, Scotch Bond Multi-Purpose Plus), two-step (Prime & Bond NT, Single Bond, Clear. l SE Bond) and one step (Adper Prompt L Pop). Results. Pooling results from 147 references showed an ongoing high scatter in the bond strength data regardless which adhesive and which bond test was used. Coefficients of variation remained high (20-50%) even with the microbond test. The reported modes of failure for all tests still included high number of cohesive failures. The ranking seemed to be dependant on the test used. Significance. The scatter in dentin bond strength data remains regardless which test is used confirming Finite Element Analysis predicting non-uniform stress distributions due to a number of geometrical, loading, material properties and specimens preparation variables. This reopens the question whether, an interfacial fracture mechanics approach to analyze the dentin - adhesive bond is not more appropriate for obtaining better agreement among dentin bond related papers. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Bacterial leakage in obturated root canals-part 2: a comparative histologic and microbiologic analyses

Objective. In this study, presence of dentin infection in root canals, obturated with 4 techniques submitted to the bacterial leakage test, was evaluated using histologic methods. Study design. The canals of palatal roots of 160 molars were instrumented and divided into different groups, according to the obturation technique used (lateral condensation, MicroSeal system, Touch `n Heat + Ultrafil, and Tagger`s hybrid technique) and extent of the remaining obturation material (5 mm and 10 mm). Ten additional roots were used as control samples. The roots were sterilized in ethylene oxide and mounted on a device for evaluation of bacterial leakage using the bacteria Enterococcus faecalis for 120 days. After the leakage test, roots were microscopically analyzed for the presence of dentin infection in the root canals and dentinal tubules. Results. A total of 154 specimens were analyzed using both methodologies in the experimental groups; 50 root canals (32.4%) showed bacterial leakage at the end of the experimental period, and 118 (76.6%) showed the presence of bacteria in the root canals using the histologic criteria. The lateral condensation technique allowed lower penetration of bacteria in the root canals and dentinal tubules, followed by Touch `n Heat + Ultrafil, MicroSeal, and Tagger`s hybrid technique, which allowed significantly greater penetration of bacteria. Root canals with 10 mm of remaining obturation material presented similar bacterial penetration as root canals with 5 mm. Conclusions. Even when an adequate seal of the apical foramen was shown by the absence of turbidity in the bacterial leakage test, E. faecalis dentin infection was present in a high percentage of the root canals after 120 days of root filling exposure to the bacteria. Tagger`s hybrid technique presented greater quantity of bacteria in histologic sections than root canals obturated with the other techniques. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: 788-794)

Odontogenic keratocyst and multiple supernumerary teeth in a patient with Ehlers-Danlos syndrome - A case report and review of the literature

Ehlers-Danlos syndrome (EDS) is a hereditary disorder of the connective tissue related to collagen metabolism. Deficiency or alteration of the collagen present in the tissues results in some classic signs such as skin hyperelasticity, articular hypermobility, and vascular fragility, among others. In addition, EDS oral manifestations are rarely cited in the literature. The aim of this article is to report a rare case of a young female patient with EDS who presented supernumerary teeth and an odontogenic keratocyst. There is no report in the literature of the simultaneous occurrence of these alterations. The article further highlights the importance of EDS diagnosis in patients who need dental treatment and the due care for their assistance.

Comparative efficiency of Class II malocclusion treatment with the pendulum appliance or two maxillary premolar extractions and edgewire appliances

The objective of this study was to compare, on study models and initial cephalograms, the efficiency of Class II malocclusion treatment with the pendulum appliance, and with two maxillary premolar extraction protocol. The sample consisted of 48 treated Class II malocclusion patients: group 1 comprised 22 patients (7 males, 15 females) treated with the pendulum appliance, with an initial mean age of 14.44 years and group 2, 26 patients (14 males, 12 females) treated with two maxillary premolar extractions at an initial mean age of 13.66 years. To compare the efficiency of each treatment protocol, the occlusal outcomes were evaluated on dental casts using the Peer Assessment Rating (PAR) Index and the treatment time (TT) of each group was calculated on clinical charts. The degree of treatment efficiency was calculated as the ratio between the percentage of occlusal improvement, evaluated through the PAR index, and TT. Statistical analysis was undertaken by means of t-tests. The findings demonstrated that the two maxillary premolar extraction protocol provided the occlusal outcomes in a shorter time (group 1: 45.7 months, group 2: 23.01 months) and, therefore, demonstrated greater treatment efficiency than the pendulum appliance.

Comparative distalization effects of Jones jig and pendulum appliances

Introduction: In this study, we compared the dentoalveolar changes of Class II patients treated with Jones jig and pendulum appliances. Methods: The experimental group comprised 40 Class II malocclusion subjects, divided into 2 groups: group 1 consisted of 20 patients (11 boys, 9 girls) at a mean pretreatment age of 13.17 years, treated with the Jones jig appliance for 0.91 years; group 2 comprised 20 patients (8 boys, 12 grls) at a mean pretreatment age of 13.98 years, treated with the pendulum appliance for 1.18 years. Only active treatment time of molar distalization was evaluated in the predistalization and postdistalization lateral cephalograms. Molar, second premolar, and incisor angular and linear variables were obtained. The intergroup treatment changes in these variables were compared with independent t tests. Results: The maxillary second premolars showed greater mesial tipping and extrusion in the Jones jig group, indicating more anchorage loss during molar distalization with this appliance. The amounts and the monthly rates of molar distalization were similar in both groups. Conclusions: The Jones jig group showed greater mesial tipping and extrusion of the maxillary second premolars. The mean amounts and the monthly rates of first molar distalization were similar in both groups. (Am J Orthod Dentofacial Orthop 2009;135:336-42)

Comparative histomorphometric and tomographic analysis of maxillary sinus floor augmentation in rabbits using autografts and xenografts

Our goal was to evaluate bone neoformation promoted by a bovine xenograft composite (XC) compared with autogenous graft for maxillary sinus augmentation in a rabbit model. The left maxillary sinus of 18 male rabbits was filled with 200 mg of cortical and cancellous autogenous bone and the right sinus was filled with 200 mg of a composite comprised organic and inorganic bovine matrices, pool of bBMPs and collagen. Postoperative implant intervals of 2, 4, and 8 weeks were analyzed. Differences in the bone optical density among the groups and experimental periods were evaluated by computed tomography analysis. The tissue response was evaluated by histomorphometric analysis of the newly formed bone, connective tissue and/or granulation tissue, residual material, and bone marrow. The tomographic analyses showed a maximum optical density in the 4-week period for both groups. Histologically, an inflammatory infiltrate was observed at 2 weeks in the XC group but exclusively around the organic particles of the biomaterial. Regarding to the amount of newly formed bone, no statistical differences (p > 0.05) were observed among the two treatments throughout the implant intervals. However, by the end of the 8 weeks, the quantity of bone marrow was two times greater (p < 0.05) in the control group than in the XC group. In conclusion, the xenograft composite promotes formation of new bone in a similar fashion to autogenous bone and could therefore be considered a biomaterial with potential applications as a bone substitute in maxillary sinus floor augmentation. (C) 2007 Wiley Periodicals, Inc.

Comparative study on antioxidant effects and vascular matrix metalloproteinase-2 downregulation by dihydropyridines in renovascular hypertension

The vascular remodeling associated with hypertension involves oxidative stress and enhanced matrix metalloproteinases (MMPs) expression/activity, especially MMP-2. While previous work showed that lercanidipine, a third-generation dihydropyridine calcium channel blocker (CCB), attenuated the oxidative stress and increased MMP-2 expression/activity in two-kidney, one-clip (2K1C) hypertension, no previous study has examined whether first- or second-generation dihydropyridines produce similar effects. We compared the effects of nifedipine, nimodipine, and amlodipine on 2K1C hypertension-induced changes in systolic blood pressure (SBP), vascular remodeling, oxidative stress, and MMPs levels/activity. Sham-operated and 2K1C rats were treated with water, nifedipine 10 mg/kg/day, nimodipine 15 mg/kg/day, or amlodipine 10 mg/kg/day by gavage, starting 3 weeks after hypertension was induced. SBP was monitored weekly. After 6 weeks of treatment, quantitative morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin-stained sections. Aortic and systemic reactive oxygen species levels were measured by using dihydroethidine and thiobarbituric acid-reactive substances (TBARs), respectively. Aortic MMP-2 levels and activity were determined by gelatin zymography, in situ zymography, and immunofluorescence. Nifedipine, nimodipine, or amlodipine attenuated the increases in SBP in hypertensive rats by approximately 17% (P<0.05) and prevented vascular hypertrophy (P<0.05). These CCBs blunted 2K1C-induced increases in vascular oxidative stress and plasma TBARs concentrations (P<0.05). All dihydropyridines attenuated the increases in aortic MMP-2 levels and activity associated with 2K1C hypertension. These findings suggest lack of superiority of one particular dihydropyridine, at least with respect to antioxidant effects, MMPs downregulation, and inhibition of vascular remodeling in hypertension.

Feasibility of an evidence-based literature search service for general practitioners

Objective: To test the feasibility of an evidence-based clinical literature search service to help answer general practitioners' (GPs') clinical questions. Design: Two search services supplied GPs who submitted questions with the best available empirical evidence to answer these questions. The GPs provided feedback on the value of the service, and concordance of answers from the two search services was assessed. Setting: Two literature search services (Queensland and Victoria), operating for nine months from February 1999. Main outcome measures: Use of the service; time taken to locate answers; availability of evidence; value of the service to GPs; and consistency of answers from the two services. Results: 58 GPs asked 160 questions (29 asked one, 11 asked five or more). The questions concerned treatment (65%), aetiology (17%), prognosis (13%), and diagnosis (5%). Answering a question took a mean of 3 hours 32 minutes of personnel time (95% Cl, 2.67-3.97); nine questions took longer than 10 hours each to answer, the longest taking 23 hours 30 minutes. Evidence of suitable quality to provide a sound answer was available for 126 (79%) questions. Feedback data for 84 (53%) questions, provided by 42 GPs, showed that they appreciated the service, and asking the questions changed clinical care. There were many minor differences between the answers from the two centres, and substantial differences in the evidence found for 4/14 questions. However, conclusions reached were largely similar, with no or only minor differences for all questions. Conclusions: It is feasible to provide a literature search service, but further assessment is needed to establish its cost effectiveness.