Root canal obturation by ultrasonic condensation of gutta-percha. Part II: an in vitro investigation of the quality of obturation

AIM: To compare the quality of root canal obturation using ultrasonic or cold condensation of gutta-percha and to determine the effect of power setting and activation time on the quality of obturation using the former technique. METHODOLOGY: An extracted human maxillary canine was used in an in vitro split tooth model to allow repeated obturation of the same root canal system using an ultrasonic device to thermocompact gutta-percha without sealer. After each obturation, the root filling was removed from the tooth to allow evaluation of its quality and for the tooth to be re-obturated. The influence of combinations (n = 10 per combination) of power setting (1, 3, 5) and activation times (4, 10, 15 s) was tested on the quality of root filling, assessed by measuring the voids within the body of the root filling as well as at the surface. Image analysis was used to quantify the voids within the body of the root filling. Cold lateral condensation of gutta-percha served as a control. RESULTS: Both surface and cross-sectional analyses revealed that different power setting and activation time combinations produced significantly fewer voids than cold lateral condensation (P < 0.05) at the apical, mid-root and coronal levels. CONCLUSIONS: Taking surface and cross-sectional analysis together only power setting 5 and activation times of 10 and 15 s consistently produced ultrasonically thermocompacted root canal fillings with fewer voids than cold lateral condensation without sealer.     

Creation of oral care flavours to deliver breath-freshening benefits

Objective:  Oral care products deliver breath freshening primarily via mechano-chemical cleaning or by antimicrobial active systems. Dental flavours provide taste benefits, and freshen breath mainly by sensorial masking. We aimed to determine whether flavours could deliver breath freshening in products by inhibiting bacterial volatile sulphide compound (VSC) production.
Subjects and methods:  Flavour materials were screened for inhibition of hydrogen sulphide formation by Klebsiella pneumoniae in vitro , grouped by efficacy, and data provided to flavourists. Flavours were formulated to maximize the content of VSC-effective ingredients and re-screened to confirm performance. Extensive, iterative testing of flavours identified reliable creative rules to deliver efficient inhibition of H₂S generation. Breath-freshening flavours in whole products were then tested in-house in a 'breath freshness panel'.
Main outcome measures:  Malodour of panellists (not preselected for malodour score) was scored before and after product use, on the 'Rosenberg' 0–5 scale, together with residual flavour score, by extensively trained judges. Products were tested in double-blind, crossover studies, and results analysed using ANOVA.
Results and conclusions:  Products flavoured using these rules delivered significantly greater breath freshening at 2 h than control products, and equivalent benefits to products containing 0.1% (w/w) triclosan or 0.2% (w/w) zinc sulphate.     

Orthodontic treatment for prominent upper front teeth in children

Background: Prominent upper front teeth are an important and potentially harmful type of orthodontic problem. This condition develops when the child’s permanent teeth erupt and children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of the teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait until the child is older and provide treatment in early adolescence. When treatment is provided during adolescence the orthodontist may provide treatment with various orthodontic braces, but there is currently little evidence of the relative effectiveness of the different braces that can be used. Objectives: To assess the effectiveness of orthodontic treatment for prominent upper front teeth, when this treatment is provided when the child is 7 to 9 years old or when they are in early adolescence or with different dental braces or both. Search strategy: The Cochrane Oral Health Group’s Trials Register, CENTRAL, MEDLINE and EMBASE were searched. The handsearching of the key international orthodontic journals was updated to December 2006. There were no restrictions in respect to language or status of publication. Date of most recent searches: February 2007. Selection criteria: Trials were selected if they met the following criteria:

• ? design – randomized and controlled clinical trials;
• ? participants – children or adolescents (age < 16 years) or both receiving orthodontic treatment to correct prominent upper front teeth;
• ? interventions – active: any orthodontic brace or head‐brace, control: no or delayed treatment or another active intervention;
• ? primary outcomes – prominence of the upper front teeth, relationship between upper and lower jaws;
• ? secondary outcomes: self esteem, any injury to the upper front teeth, jaw joint problems, patient satisfaction, number of attendances required to complete treatment.

Data collection and analysis: Information regarding methods, participants, interventions, outcome measures and results were extracted independently and in duplicate by two review authors. The Cochrane Oral Health Group’s statistical guidelines were followed and mean differences were calculated using random‐effects models. Potential sources of heterogeneity were examined. Main results: The search strategy identified 185 titles and abstracts. From this we obtained 105 full reports for the review. Eight trials, based on data from 592 patients who presented with Class II Division 1 malocclusion, were included in the review. Early treatment comparisons: Three trials, involving 432 participants, compared early treatment with a functional appliance with no treatment. There was a significant difference in final overjet of the treatment group compared with the control group of ?4.04 mm (95% CI ?7.47 to ?0.6, chi squared 117.02, 2 df, P < 0.00001, I2 = 98.3%). There was a significant difference in ANB (?1.35 mm; 95% CI ?2.57 to ?0.14, chi squared 9.17, 2 df, P = 0.01, I2 = 78.2%) and change in ANB (?0.55; 95% CI ?0.92 to ?0.18, chi squared 5.71, 1 df, P = 0.06, I2 = 65.0%) between the treatment and control groups. The comparison of the effect of treatment with headgear versus untreated control revealed that there was a small but significant effect of headgear treatment on overjet of ?1.07 (95% CI ?1.63 to ?0.51, chi squared 0.05, 1 df, P = 0.82, I2 = 0%). Similarly, headgear resulted in a significant reduction in final ANB of ?0.72 (95% CI ?1.18 to ?0.27, chi squared 0.34, 1 df, P = 0.56, I2 = 0%). No significant differences, with respect to final overjet, ANB, or ANB change, were found between the effects of early treatment with headgear and the functional appliances. Adolescent treatment (Phase II): At the end of all treatment we found that there were no significant differences in overjet, final ANB or PAR score between the children who had a course of early treatment, with headgear or a functional appliance, and those who had not received early treatment. Similarly, there were no significant differences in overjet, final ANB or PAR score between children who had received a course of early treatment with headgear or a functional appliance. One trial found a significant reduction in overjet (?5.22 mm; 95% CI ?6.51 to ?3.93) and ANB (?2.27 degrees; 95% CI ?3.22 to ?1.31, chi squared 1.9, 1 df, P = 0.17, I2 = 47.3%) for adolescents receiving one‐phase treatment with a functional appliance versus an untreated control. A statistically significant reduction of ANB (?0.68 degrees; 95% CI ?1.32 to ?0.04, chi squared 0.56, 1 df, P = 0.46, I2 = 0%) with the Twin Block appliance when compared to other functional appliances. However, there was no significant effect of the type of appliance on the final overjet. Authors’ conclusions: The evidence suggests that providing early orthodontic treatment for children with prominent upper front teeth is no more effective than providing one course of orthodontic treatment when the child is in early adolescence.     

Δ4-3-oxosteroid-5β-reductase deficiency: Responses to oral bile acid therapy and long-term outcomes

BACKGROUND Disorders of primary bile acid synthesis may be life-threatening if undiagnosed,or not treated with primary bile acid replacement therapy. To date, there are few reports on the management and follow-up of patients with Δ4-3-oxosteroid 5β-reductase(AKR1 D1) deficiency. We hypothesized that a retrospective analysis of the responses to oral bile acid replacement therapy with chenodeoxycholic acid(CDCA) in patients with this bile acid synthesis disorder will increase our understanding of the disease progression and permit evaluation of this treatment regimen as an alternative to the Food and Drug Administration(FDA) approved drug cholic acid, which is currently unavailable in China.AIM To evaluate the therapeutic responses of patients with AKR1 D1 deficiency to oral bile acid therapy, specifically CDCA.METHODS Twelve patients with AKR1 D1 deficiency, confirmed by fast atom bombardment ionization-mass spectrometry analysis of urine and by gene sequencing for mutations in AKR1 D1, were treated with differing doses of CDCA or ursodeoxycholic acid(UDCA). The clinical and biochemical responses to therapy were monitored over a period ranging 0.5-6.4 years. Dose adjustment, to optimize the therapeutic dose, was based on changes in serum biochemistry parameters,notably liver function tests, and suppression of the urinary levels of atypical hepatotoxic 3-oxo-Δ4-bile acids measured by mass spectrometry.RESULTS Physical examination, serum biochemistry parameters, and sonographic findings improved in all 12 patients during bile acid therapy, except one who underwent liver transplantation. Urine bile acid analysis confirmed a significant reduction in atypical hepatotoxic 3-oxo-Δ4 bile acids concomitant with clinical and biochemical improvements in those patients treated with CDCA. UDCA was ineffective in down-regulating endogenous bile acid synthesis as evidenced from the inability to suppress the urinary excretion of atypical 3-oxo-Δ4-bile acids. The dose of CDCA required for optimal clinical and biochemical responses varied from 5.5-10 mg/kg per day among patients based on maximum suppression of the atypical bile acids and improvement in serum biochemistry parameters, and careful titration of the dose was necessary to avoid side effects from CDCA.CONCLUSION The primary bile acid CDCA is effective in treating AKR1 D1 deficiency but the therapeutic dose requires individualized optimization. UDCA is not recommended for long-term management.     

榆耳发酵液中新倍半萜——榆耳三醇的结构

从榆耳(Gloeostereum incarnatum S.Ito et Imai)的液体发酵物中经层析分离得一新倍半萜榆耳三醇(gloeosteretriol),根据红外光谱、核磁共振谱和质谱数据推定其结构为Ⅰ,并用X-射线晶体衍射进一步确证其结构和立体构型。     

Analysis of HSD3B7 knockout mice reveals that a 3alpha-hydroxyl stereochemistry is required for bile acid function

Primary bile acids are synthesized from cholesterol in the liver and thereafter are secreted into the bile and small intestine. Gut flora modify primary bile acids to produce secondary bile acids leading to a chemically diverse bile acid pool that is circulated between the small intestine and liver. A majority of primary and secondary bile acids in higher vertebrates have a 3alpha-hydroxyl group. Here, we characterize a line of knockout mice that cannot epimerize the 3beta-hydroxyl group of cholesterol and as a consequence synthesize a bile acid pool in which 3beta-hydroxylated bile acids predominate. This alteration causes death in 90% of newborn mice and decreases the absorption of dietary cholesterol in surviving adults. Negative feedback regulation of bile acid synthesis mediated by the farnesoid X receptor (FXR) is disrupted in the mutant mice. We conclude that the correct stereochemistry of a single hydroxyl group at carbon 3 in bile acids is required to maintain their physiologic and regulatory functions in mammals.     

Mammary gland differentiation by early life exposure to enantiomers of the soy isoflavone metabolite equol

The role of soy in reducing breast cancer risk has been suggested to be associated with early exposure to isoflavones, which alter mammary gland morphology. The objective of the study was to determine the effect of dietary exposure to the enantiomers of a key soy isoflavone metabolite, equol, on mammary gland development and later chemoprotection using the DMBA-induced animal model of breast cancer. Animals were exposed to S-(−)equol or R-(+)equol (250 mg/kg diet) during the neonatal (0–21 days) or prepubertal (21–35 days) periods only. Histological evaluation of the mammary glands showed that both enantiomers fed neonatally via the dam led to significant precocial mammary gland differentiation. By day 50, early S-(−)equol or R-(+)equol exposure resulted in a decrease in immature terminal end structures and an increase in mature lobules, suggesting an early ‘imprinting’ effect. Despite these morphological changes to the mammary gland, neonatal and prepubertal exposure to equol had no long-term chemoprevention against mammary tumors induced by DMBA, although for R-(+)equol there was a trend to delaying tumor formation. In summary, early exposure to equol was not chemopreventive, but neither did it increase tumor formation in response to DMBA, suggesting exposure in early life does not influence breast cancer risk.