Clinical and Fiberoptic Endoscopic Evaluation of Swallowing in Robin Sequence Treated With Nasopharyngeal lntubation: The Importance of Feeding Facilitating Techniques

Objective: To evaluate oral feeding capacity, the swallowing process, and risk for aspiration, both clinically and during fiberoptic endoscopic evaluation of swallowing, in infants with isolated Robin sequence treated exclusively with nasopharyngeal intubation and feeding facilitating techniques. Design: Longitudinal and prospective study. Setting: Hospital de Reabilitacao de Anomalies Craniofaciais, University of Sao Paulo, Bauru, Brazil. Patients: Eleven infants with isolated Robin sequence, under 2 months of age, treated with nasopharyngeal intubation. Interventions: Feeding facilitating techniques were applied in all infants throughout the study period. The infants were evaluated clinically and through fiberoptic endoscopic evaluation of swallowing at first, second, and, if necessary, third week of hospitalization (T1, T2, T3). The mean volume of ingested milk was registered during clinical evaluation, and events were registered during feeding. Results: The respiratory status of all infants was improved after nasopharyngeal intubation; 72% of them presented risk for aspiration during fiberoptic endoscopic evaluation of swallowing at T1. This risk was less frequent when thickened milk was given to the infants and at subsequent evaluations (T2 and T3). Conclusions: Nasopharyngeal intubation aids in stabilizing the airway in isolated Robin sequence, but it does not relate directly to feeding. The risk for aspiration was present in most of the infants, mainly during the first week of hospitalization, and improved within a few weeks, after the use of feeding facilitating techniques.

The effect of temperature and fasting period on the viability of free-living females of Rhipicephalus sanguineus (Acari : Ixodidae) under laboratory conditions

Little is known about the effect of temperature on viability of free-living phases of the life cycle of Rhipicephalus sanguineus (Latreille, 1806) despite of its importance as vector of several pathogens. Knowledge of the effect of abiotic factors on the capacity of a given tick species to infest new hosts is important for routine experimental activities under laboratory conditions, and may be relevant to understand the transmission of pathogens. The study evaluates the viability of R. sanguineus females held at 18 +/- 1, 27 +/- 1 and 32 +/- 1 degrees C and 80 +/- 5% RH (saturation deficits of 3.0, 5.3 and 7.2 mmHg, respectively) for three fasting periods (3 and 20 days and the day when female mortality reached approximately 50% after ecdysis), under laboratory conditions. In general, the best result on viability was obtained when rabbits were infested with unfed female ticks after three or 20 fasting days at both 27 +/- 1 and 32 +/- 1 degrees C and 80 +/- 5% RH.

Biological aspects of Amblyomma brasiliense (Acari : Ixodidae) under laboratory conditions

Although Amblyomma brasiliense Arag (a) over tildeo 1908 has been reported as one of the most aggressive ticks to humans in Brazil, information about the biology of this tick species is virtually inexistent. This work reports data on the life cycle of A. brasiliense fed on rabbits and pigs and maintained in an incubator at 20 degrees C, 90% RH and 12 h of light for off-host development. Tick yield of adult females fed on pigs and rabbits was 81.2% and 58.3%, respectively. Females fed on pigs had mean engorgement weight of 862.3 mg and egg mass of 208 mg, while females fed on rabbits had mean engorgement weight of 606.1 mg and egg mass of 160 mg; these values did not differ statistically between host species. Feeding period of female ticks fed on pigs (10 days) was significantly shorter than that on rabbits (17 days). Mean preoviposition period was slightly longer (35.9 days) for ticks fed on pigs than on rabbits (30 days). The minimum incubation period of eggs of ticks from both host species was similar and over 100 days. Egg production efficiency was low for females fed on both hosts (less than 30% and 20% for ticks from pigs and rabbits, respectively). More than 55% of larvae and 79% of nymphs fed on rabbits, set free inside the feeding chambers, engorged successfully. These ticks attained an engorgement weight of 1.3 and 18.2 mg, respectively, and fed for approximately 5 days. The minimum pre-molt period was 30 days for engorged larvae and over 44 days for nymphs. Molting success was low, less than 50% in the case of larvae and less than 20% for nymphs. Further studies are required to better determine the off-host requirements of this tick species.

Life cycle of Ixodes luciae (Acari: Ixodidae) in the laboratory

The life cycle of Ixodes luciae was evaluated for five consecutive generations in the laboratory. Wild mice Calomys callosus and laboratory rats Rattus norvegicus were used as hosts for larvae and nymphs. For adult ticks, opossums Didelphis aurita were used as hosts. Off-host developmental periods were observed in an incubator at 27A degrees C and 95% RH. The life cycle of I. luciae lasted 95-97 days, excluding prefeeding periods. C. callosus, one of the natural host species for I. luciae immature stages, was shown to be much more suitable than the artificial host R. norvegicus. Significantly (P < 0.05), more larvae and nymphs successfully fed on C. callosus than on R. norvegicus. When tick-na < ve C. callosus were exposed to three consecutive larval infestations at 24-day intervals, recovery of engorged larvae were greater in the second and third infestations, indicating that previous infestations did not induce acquired resistance to ticks. Larval feeding period typically varied from 5 to 10 days on R. norvegicus, but was significantly (P < 0.05), longer on C. callosus (range, 7-34 days). The majority (71.7%) of I. luciae adult females successfully fed and oviposited after exposed to D. aurita. Mean engorged weight (581.9 mg; range, 237.1-796.0 mg) of these females were much higher than those previously reported for other New World Ixodes species. Our results are in accordance to the current literature that appoints opossums Didelphidae and small rodents (e.g., C. callosus) natural hosts for I. luciae immature and adult stages, respectively.

Performance of techniques used for re-attachment of endodontically treated crown fractured teeth

Objectives: The aim of this study was to compare the fracture strength of three techniques used to re-attach tooth fragments in sound and endodontically treated fractured teeth with or without fiber post placement. Material and methods: Ninety human lower incisors were randomly divided into three groups of 30 teeth each. In group A teeth were not subjected to endodontic treatment; while teeth from groups B and C were endodontically treated and the pulp chamber restored with a composite resin. All teeth were fractured by an axial load applied to the buccal area in order to obtain tooth fragments. Teeth from each group were then divided into three subgroups, according to the re-attachment technique: bonded-only, buccal-chamfer and circumferential chamfer. Before the re-attachment procedures, fiber posts were placed in teeth from group C using dual cure resin luting cement (Duo-Link). All teeth (groups A-C) had the fragments re-attached using a same dual cure resin luting cement. in the bonded-only group, no additional preparation was made. After re-attachment of the fragment, teeth from groups buccal and circumferential chamfer groups had a 1.0 mm depth chamfer placed in the fracture line either on buccal surfaceor along the buccal and lingual surfaces, respectively. increments of microhybid composite resin (Tetric Ceram) were used in subgroups buccal chamfer and circumferential chamfer to restore the chamfer. The specimens were loaded until fracture in the same pre-determined area. The force required to detach each fragment was recorded and the data was subjected to a three-way analysis of variance where factors Group and Re-attachment technique are independent measures and Time of fracture is a repeated measure factor (first and second) and Tukey`s test (alpha = 0.05). Results: The main factors Re-attachment technique (p = 0.04) and Time of fracture (p = 0.02) were statistically significant. The buccal and circumferential chamfer techniques were statistically similar (p > 0.05) and superior to the bonded-only group (p < 0.05). The first time of fracture was statistically superior to second time of fracture (p < 0.001). Conclusions: The use of fiber post is not necessary for the reinforcement of the tooth structure in re-attachment of endodontically treated teeth. When bonding a fractured fragment, the buccal or circumferential re-attachment techniques should be preferable in comparison with the simple re-attachment without any additional preparation. None of the techniques used for re-attachment restored the fracture strength of the intact teeth. (C) 2008 Elsevier Ltd. All rights reserved.

Clinical versus laboratory adhesive performance to wet and dry demineralized primary dentin

Purpose: To evaluate the influence of dentin moisture on bond strengths of an etch-and-rinse bonding agent to primary dentin clinically and in the laboratory. Methods: The sample consisted of two groups of 20 caries-free primary second molars: molars in exfoliation period (clinical group) and extracted molars (laboratory group). Class I cavities were prepared in all specimens leaving a flat dentin surface on the pulpal floor. A two-step etch-and-rinse adhesive was vigorously rubbed on either dry (n= 5) or wet demineralized dentin (n= 5) under clinical or laboratory conditions. After restorative procedures, the teeth from the clinical group were extracted after 20 minutes. All samples were processed and underwent microtensile bond strength test and silver nitrate uptake evaluation under scanning electron microscopy. Results: Statistically higher bond strength values were observed when the bonding was performed under laboratory conditions and on a wet demineralized dentin. Most of the failures were adhesive and mixed irrespective of the experimental condition. Silver nitrate uptake occurred in all groups irrespective of the experimental condition. Resin-dentin bond strengths produced in the laboratory in primary teeth may overestimate those produced under clinical circumstances. (Am J Dent 2011;24:221-225).

Analysis of four gutta-percha techniques used to fill mesial root canals of mandibular molars

P>Aim To compare the percentage of gutta-percha, sealer and voids and the influence of isthmuses in mesial root canals of mandibular molars filled with different techniques. Methodology Canals in 60 mesial roots of mandibular first molars were prepared with ProTaper instruments to size F2 (size 25, 0.08 taper) and filled using a single-cone, lateral compaction, System B or Thermafil techniques. An epoxy resin sealer was labelled with Rhodamine-B dye to allow analysis under a confocal microscope. The percentage of gutta-percha, sealer and area of voids was calculated at 2, 4 and 6 mm from the apex, using Image Tool 3.0 software. Statistical analysis was performed using nonparametric Kruskal-Wallis and Dunn tests (P < 0.05). The influence of isthmuses on the presence or absence of voids was evaluated using the Fisher test. Results At the 2 mm level, the percentage of gutta-percha, sealer and voids was similar amongst the System B, lateral compaction and single-cone techniques. The single-cone technique revealed significantly less gutta-percha, more sealer and voids in comparison with the Thermafil technique at the 2 and 4 mm level (P < 0.05). The analysis of all sections (2, 4 and 6 mm) revealed that more gutta-percha and less sealer and voids were found in root canals filled with Thermafil and System B techniques (P < 0.05). The Fisher test revealed that the presence of isthmuses increased the occurence of voids in the lateral compaction group only (P < 0.05). Conclusion Gutta-percha, sealer filled area and voids were dependent on the canal-filling technique. The presence of isthmuses may influence the quality of root filling.

Bacterial leakage in root canals obturated by different techniques. Part 1: microbiologic evaluation

Objective. This study compared the coronal bacterial leakage of root canals obturated by different techniques and with different lengths of obturation. Study design. The canals of palatal roots of 160 maxillary molars were instrumented and divided into different groups according to the obturation technique used (lateral condensation, Microseal system, Touch `n Heat + Ultrafil system, or Tagger`s hybrid technique) and the length of obturation (5 mm or 10 mm). The roots were impermeabilized, sterilized in ethylene oxide, and mounted on a device for evaluation of the bacterial leakage. Results. Tagger`s hybrid technique produced a statistically greater number of specimens with coronal leakage than the other techniques. There was no statistically significant difference between the lateral condensation, Touch `n Heat + Ultrafil, and Microseal groups. Root canals with 10 mm of obturation produced a statistically significantly smaller number of specimens with leakage than root canals with 5 mm of obturation. Conclusion. Tagger`s hybrid technique produced a greater number of specimens with coronal leakage than the other techniques, and a greater number of root canals with 5 mm of obturation leaked than root canals with 10 mm of obturation.

Thermal/mechanical simulation and laboratory fatigue testing of an alternative yttria tetragonal zirconia polycrystal core-veneer all-ceramic layered crown design

This study evaluated the stress levels at the core layer and the veneer layer of zirconia crowns (comprising an alternative core design vs. a standard core design) under mechanical/thermal simulation, and subjected simulated models to laboratory mouth-motion fatigue. The dimensions of a mandibular first molar were imported into computer-aided design (CAD) software and a tooth preparation was modeled. A crown was designed using the space between the original tooth and the prepared tooth. The alternative core presented an additional lingual shoulder that lowered the veneer bulk of the cusps. Finite element analyses evaluated the residual maximum principal stresses fields at the core and veneer of both designs under loading and when cooled from 900 degrees C to 25 degrees C. Crowns were fabricated and mouth-motion fatigued, generating master Weibull curves and reliability data. Thermal modeling showed low residual stress fields throughout the bulk of the cusps for both groups. Mechanical simulation depicted a shift in stress levels to the core of the alternative design compared with the standard design. Significantly higher reliability was found for the alternative core. Regardless of the alternative configuration, thermal and mechanical computer simulations showed stress in the alternative core design comparable and higher to that of the standard configuration, respectively. Such a mechanical scenario probably led to the higher reliability of the alternative design under fatigue.

Laboratory evaluation of the physicochemical properties of a new root canal sealer based on Copaifera multijuga oil-resin

Aim To compare a new root canal sealer based on Copaifera multijuga oil-resin (Biosealer) using three other established sealers (Sealer 26 (R), Endofill (R) and AH plus (R)) in terms of their physicochemical properties. Methodology The study was carried out according to the requirements of Specification Number 57 of the American Dental Association (ADA) and consisted of the following tests: setting time, flow, film thickness, dimensional stability, radiopacity and solubility/disintegration. Data were analysed statistically using anova and Tukey`s test for multiple comparisons. The significance level was set at 5% for all analyses. Results Sealer 26 (R) and AH Plus (R) had the longest setting time (P < 0.05). All materials presented flow in with the ADA`s guidelines. Regarding film thick-ness, Sealer 26 (R) did not have a satisfactory performance, as it had a higher mean value than the maximum allowed by the ADA (0.05 mm), being significantly different from the other materials (P < 0.05), which had mean values for film thickness in accordance with the ADA`s recommendations. Regarding the solubility and disintegration, only Endofill (R) did not meet the ADA`s specifications and presented the worst results of all materials (P < 0.05). Sealer 26 (R) presented the greatest dimensional changes and differed significantly from all other sealers (P < 0.05). Biosealer had the lowest radiopacity values and was significantly different from the other sealers (P < 0.05). Conclusion The experimental sealer based on Copaifera multijuga oil-resin presented satisfactory results in the physicochemical tests required by the ADA.