Feed form and perch design do not interact to production performance, gastrointestinal tract traits, behaviour and welfare of laying hens reared in enriched cages.

1. It was hypothesised that perch material and design may affect utility and maintenance energy demand in laying hens, affecting their feed form preferences and daily feed consumption. Accordingly, perch design and feed form on hen performance, gastrointestinal tract functions and some behavioural and welfare-related traits were studied in laying hens (ATAK-S) reared in enriched colony cages from 24 to 40 weeks of age.2. The experiment was a 2 × 2 factorial investigating two perch materials and design (circular steel or mushroom-shaped plastic) and feed form (mash or crumble). A total of 396 hens were randomly assigned to one of the four treatment groups with nine replicates each (11 birds per replicate).3. Except for feeding behaviour and prevalence of foot pad dermatitis at 40 weeks of age, the modification of the perch design did not have a significant effect on the traits examined. Mushroom-shaped plastic perches reduced feeding behaviour (p < 0.01) and the incidence of foot pad dermatitis at 40 weeks of age (p < 0.001).4. Performance traits were not affected by feed form. Intake, final body weight and FCR for crumble-fed laying hens were greater than those fed mash (p < 0.01).5. Hens fed mash had higher (p < 0.01) relative gizzard weights along with lower (p < 0.05) pH values, pancreatic chymotrypsin, amylase and lipase activities (p < 0.05), and duodenal absorption surface areas (p < 0.01). Ultimately, this gave higher protein digestibility (p < 0.05) compared to those receiving crumble.6. In conclusion, in enriched cage rearing systems, mashed feed was preferred over crumble to efficiently maintain productive performance. Compared to circular steel, plastic mushroom-shaped perches were associated with better footpad health and welfare.

The effect of endodontic irrigants on the microtensile bond strength of different dentin adhesives.

OBJECTIVES: The aim of this study was to determine the influence of irrigants on bond strength of adhesive systems. MATERIALS AND METHODS: Superficial dentin surfaces of 60 extracted molars were divided into 15 groups, according to irrigants and adhesives. In the control groups, surfaces were irrigated with distilled water. In experimental groups, sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA) + NaOCl, chlorhexidine (CHX), and NaOCl + sodium ascorbate were used as irrigants. Resin composites were then built up using Single Bond, Clearfil SE Bond, and Xeno 3 as adhesives. The microtensile bond strength of groups was determined. Data were statistically analyzed by two-way analysis of variance (ANOVA), one-way ANOVA, and the Bonferroni test. RESULTS: NaOCl reduced bond strength of Single Bond and Clearfil SE Bond (P < 0.01). For all adhesive systems, EDTA + NaOCl-treated groups exhibited lower bond strength than control groups (P < 0.01). CHX decreased bond strength of Single Bond (P < 0.01). Application of sodium ascorbate improved compromised bond strength to NaOCl-treated dentin (P < 0.01). CONCLUSION: Different irrigants had several effects on bonding of different adhesives. Sodium ascorbate after NaOCl could restore compromised bond strengths.

Response of human pulpal tissue to orthodontic extrusive applications.

The aim of this study was to investigate histologically the human pulp response to orthodontic extrusive force applications. In group 1, 20 teeth were extruded with the use of a fixed sectional orthodontic appliance. In group 2, 20 teeth were extruded by means of 1/4-inch 4.5-oz elastics. The test periods were 10 and 40 days. None of the teeth in the groups showed any inflammatory reactions or reparative dentin formation at the test periods. Five teeth from the elastics group and two teeth from the sectional appliance group showed large and numerous pulp stones in the serial sections (17.5% of all cases). Seven teeth from the sectional appliance group and two teeth from the elastics group showed odontoblast aspiration into the dentin tubules (22.5%). The results of the study showed that the extrusive forces applied in this study did not cause significant pathological changes in human pulp tissue.

Technique sensitivity: biological factors contributing to clinical success with various restorative materials.

Since the 1950s, clinicians have relied on various formulations of Ca(OH)2 to stimulate dentin bridge formation. Various studies (Kozlov and Massler, 1966; Massler, 1967; Brännström, 1978; Cox et al., 1987; Snuggs et al., 1993) have demonstrated that pulp healing and dentin bridging can occur against a pH spectrum of materials. Recent studies (Akimoto et al., 1998; Cox et al., 1998, 1999; Tarim et al., 1998; Kitasako et al., 1999; Hafez et al., 2000) have reported successful pulp healing and dentin bridging using adhesives for direct capping of exposed pulps. However, others (Costa et al., 1997; Stanley and Pameijer, 1997; Pameijer, 1998; Hebling et al., 1999; Carvalho et al., 2000) have reported unsatisfactory results when exposures were direct-capped with adhesives. Biological and technical factors, or a combination of both, might be postulated to explain these differences. Recent studies have demonstrated that biological success is dependent upon proper hemorrhage control at the exposure site. This review explores the differences and common factors influencing successful dentin bridging, focusing on data derived from animal studies conducted according to ISO usage guidelines for cavity preparation and material placement. In the past, there has been concern that etching of vital dentin leads to immediate pulp death due to low pH. Recent studies have reported that acidic cements cause breakdown of only the smear layer and fail to seal the restoration interface, leading to inflammation and necrosis. A properly hybridized dentinadhesive interface provides a "bacteriometic" seal to both dentin and pulp tissues. Recent ISO usage studies have shown a high incidence of dentin bridging with adhesives following proper hemorrhage control and removal of both operative debris and biofilm at the dentin-pulp interface by agents such as NaOCl. These are important technique-sensitivity factors to be considered for pulp healing and dentin bridge formation.

Human pulp reaction to dentine bonded amalgam restorations: a histologic study.

OBJECTIVE: The aim of this study was to investigate the human pulp response to Scotchbond Multi Purpose Plus (SMPP) bonding agent in non-exposed Class V cavities. METHODS: SMPP was placed in 24 of 40 cavites according to manufacturer's instructions and the cavities were restored with amalgam. The remaining 16 cavities were capped with a calcium hydroxide formulation (Dycal) sealed with zinc-oxide eugenol, and restored with the amalgam. After extraction at 10 and 35 days, the teeth were fixed, sectioned and stained for light microscopy. RESULTS: All Dycal-capped teeth, at both 10 and 35 days, exhibited no pulp inflammation and no demonstrable bacteria. Six cases sealed with SMPP at 10 days showed no pulp inflammation or stained bacterial profiles. The remaining six teeth demonstrated mild to moderate inflammatory pulpal responses and five out of these six cases exhibited stained bacterial profiles. Nine out of 12 teeth showed no inflammatory pulp responses at 35 days, the remaining three cases exhibited mild to moderate pulp inflammation without stained bacteria. CONCLUSIONS: None of the teeth sealed with SMPP presented severe inflammatory pulpal reactions histologically. SMPP did not exhibit significant deleterious effects on the human pulp tissue during the test periods.

A comparative scanning electron microscopic study on the characteristics of demineralized dentin root surface using different tetracycline HCl concentrations and application times.

BACKGROUND: The use of demineralizing agents has been reported to enhance the degree of connective tissue attachment to denuded roots. Of the agents used, tetracycline HCI has received the most attention. METHODS: The purpose of this study was to evaluate and compare the SEM surface morphology of human root dentin following various concentrations and application times of tetracycline HCl. The surface characteristics were compared and the width of dentin tubule orifices were measured and analyzed. Twelve human teeth were collected and stored in distilled water after soft tissue removal using hand instruments. The apical third of each root was removed and remaining mid-root region was sectioned longitudinally through the root canal following removal of its cementum with a fine diamond bur. A total of 48 dentin specimens were randomly divided into 8 groups for conditioning at different tetracycline HCl concentrations, at 0, 10, 25, 50, 75, 100, 125, and 150 mg/ml. Application times for each group were 1, 3, and 5 minutes. Immediately following treatment procedures, the specimens were rinsed, fixed in GTA-PBF, dehydrated, and prepared for SEM. Each specimen was examined at 2 magnification values, representative fields photographed, and data tested by one-way ANOVA and paired t test statistical analysis. RESULTS: Our results indicate that the use of tetracycline HCl solution between 50 mg/ml and 150 mg/ml showed a statistically significant opening of dentin tubules. All tetracycline HCl groups at 1, 3, and 5 minutes show smear layer removal from the dentin surface. CONCLUSIONS: Dentin demineralization is not time dependent at all concentrations of tetracycline HCI.

Surface finish produced on resin composites by new polishing systems.

OBJECTIVE: There is a demand for more efficient and finer polishing of resin composite restorations. This study compared the use of some new systems, with new or reduced numbers of abrasive instruments, to polish representative resin composites. METHOD AND MATERIALS: Super-Snap Rainbow Technique Kit, Sof-Lex Pop-On System, and Enhance Finishing and Polishing System were used to prepare the surfaces of blocks of seven different hybrid or microfilled resin composites. For each system, three instruments were used for 30 seconds each in a standard manner. The average surface roughness of the polished surfaces was determined by profilometer. RESULTS: Visually, all surfaces were of clinically acceptable luster. By profilometer ranking, the Super-Snap Rainbow Kit produced the smoothest surfaces, followed by the Sof-Lex Pop-On System disks (which were not statistically different), and the Enhance System. CONCLUSION: The Super-Snap Rainbow Technique Kit and Sof-Lex Pop-On System provided the smoothest surfaces for all the composites tested. For several composites, the Enhance System provided less smooth surfaces, but these were also clinically acceptable.

Pulpal response to a resin-modified glass-ionomer material on nonexposed and exposed monkey pulps.

OBJECTIVE: This study evaluated the biocompatibility of a resin-modified glass-ionomer material on monkey pulps. METHOD AND MATERIALS: Standardized Class V cavities were prepared in 112 teeth distributed in six healthy adult monkeys. The resin-modified glass-ionomer cement was placed in 24 nonexposed and 36 exposed pulps according to manufacturer's instructions. ZOE was used as a control in nonexposed pulps, while calcium hydroxide was used as a control for exposed pulps. Tissues were collected at 6 to 7, 21 to 27, and 90 to 97 days. After demineralization, the teeth were serially sectioned, stained, and observed by light microscopy. RESULTS: Except for one resin-modified glass-ionomer pulp at 6 days, there were no differences between the responses of nonexposed pulps to resin-modified glass-ionomer specimens and ZOE controls. In exposed pulps, eight of 36 resin-modified glass-ionomer pulps showed various grades of inflammatory response, all associated with stained bacteria. Pulpal healing was similar in both resin-modified glass-ionomer and calcium hydroxide direct-capped exposures. Twenty-two of 26 exposed pulps restored with the resin-modified glass-ionomer cement showed dentin bridge formation at 21 and 97 days. CONCLUSION: The resin-modified glass-ionomer material exhibited acceptable biologic compatibility in exposed and nonexposed cavities.

Biocompatibility of primer, adhesive and resin composite systems on non-exposed and exposed pulps of non-human primate teeth.

PURPOSE: To evaluate the histologic response of 332 non-exposed and 127 exposed monkey pulps applying nine adhesive systems. MATERIALS AND METHODS: Class V and Class I cavities were used in non-exposed and exposed monkey pulps at the three ISO usage time intervals. RESULTS: There were no histologic differences in pulp responses among the nine adhesive systems used in either Class V and/or Class I cavities when compared to pulp responses of Ca(OH)2 controls at the ISO time intervals. The nine adhesive systems and resin composites are non-toxic to either non-exposed or exposed pulps, being biologically compatible to pulp tissues when placed on mechanical pulp exposures following hemorrhage control with a 2.5% NaOCl and per manufacturers' directions. It is imperative that clinicians understand the biological importance of hemorrhage control as well as the technique sensitivity of hydrophilic primers in order to optimize the efficacy of adhesives for clinical success against microleakage of bacterial factors.

Biocompatibility of Optibond and XR-Bond adhesive systems in nonhuman primate teeth.

This study evaluated the histologic responses of two different adhesive systems on the teeth of seven healthy adult monkeys. Class V cavities in 128 teeth were observed at 7,21 to 27, and 90 to 97 days. Statistical data showed no significant differences in pulp inflammation between the Optibond (Kerr), XR-Bond (Kerr), and IRM (Caulk) groups in pulps at the three time intervals. Some odontoblastic disruption and inflammation was seen in pulps restored with XR-Primer at the three time intervals. Pulp healing was similar in teeth treated with both direct-capped Optibond and calcium hydroxide, and there was no significant increase in pulpal inflammation with time. No abscesses or necrotic pulps were seen in any teeth. Optibond and XR-Bond adhesive systems are biologically acceptable in nonhuman primate pulp tissues.

Biocompatability of compomer restorative systems on nonexposed dental pulps of primate teeth.

This study evaluated the histologic response of total-etched and nonetched compomer restored cavity preparations. One hundred fifteen class 5 cavity preparations were placed in the teeth of four healthy adult monkeys at 7, 27, and 90 days. A 37% H3PO4 was applied for 10 seconds and rinsed in total-etched preparations. No statistical differences were seen in inflammatory reactions among total-etched or nonetched compomers at 7, 27, and 90 days. There were no statistical differences in inflammatory cell responses among all compomer systems in regard to time intervals. Pulpal responses of compomers were greater than IRM at each time period. Pulp responses were associated with stained bacteria in 32 of 89 compomer teeth. No necrotic pulps were seen in any teeth. Statistical data show a positive correlation (P < 0.05) between bacterial presence and pulpal inflammation. IRM pulps showed no inflammation or bacterial staining. Compomers are biologically compatible with pulp tissues when bacteria are excluded.

Marginal integrity of bonded amalgam restorations.

PURPOSE: To evaluate the marginal integrity of amalgam restorations in association with four different bonding agents in an in vitro stressing system. MATERIALS AND METHODS: Cylindrical cavities were prepared in extracted human molars. The enamel-dentin interface of each cavity was treated with one of four different bonding agents and a non-bonded group. Following treatment with one of the four systems; Amalgambond (AB), Amalgambond Plus (AP) Superbond D-liner II (SD) and Bond-It (BI). Each cavity was then restored with a high-copper spherical amalgam alloy Tytin (TY). Using a load of 75 Newtons (N), a total of 100,000 cycles were applied to each restoration surface. Marginal integrity of each tooth restoration interface was replicated with epoxy and evaluated for gap width with a profilometer and SEM. RESULTS: There were no significant differences in gap width between the loaded and unloaded groups. The non-bonded group (before loading) was statistically different than AB, AP, and SD. In addition, there were no significant differences among the 4-META bonded groups, regardless of the type of bond system, whether loaded or unloaded. The four different bonding agents were significantly different after loading than the non-bonded group. Our SEM and profilometry data demonstrate that the marginal integrity of amalgam alloy restorations is significantly improved by use of bonding systems.

Histopathological investigation of the effects of various glass-ionomer cements on dental pulp.

In this study, an attempt was made to examine the effects of 4 glass ionomer cements on pulp. For this purpose, 30 incisors from 3 dogs were employed. Glass-ionomer cements commercially known as Ketac-bond, Kromoglass 1, Vitrebond and Logobond WM were administered in Black Class V cavities drilled on the vestibular surfaces of the teeth, with zinc oxide/eugenol cement being applied to a control group. Teeth were extracted at 7, 30 and 90 days and assessed accordingly. The pulpal tissues of the teeth were reviewed under light microscope with respect to odontoblastic activity, odontoblast aspiration, fibrosis, vascularization and erythrocyte accumulation, presence of inflammatory cells, necrosis, and reparative dentine. Various findings were obtained from 4 different glass-ionomer cements, which were evaluated according to the criteria stated above; however, in no section were inflammatory cells or necrosis encountered. Therefore, none of the substances utilized in our study was found to have an excessive toxic effect on pulpal tissue.