Hydrofluoric acid concentrations: Effect on the cyclic load-to-failure of machined lithium disilicate restorations

Objectives

To evaluate the effects of the etching with different hydrofluoric acid (HF) concentrations on the cyclic load-to-failure $(C_{Lf})$ of machined lithium disilicate crowns cemented to dentin analogue material.

Comparative evaluation of different fixation techniques of the sagittal split ramus osteotomy in 10 mm advancements: Mechanical testing and screw insertion torque

Purpose

To compare the mechanical characteristics of five techniques for the functionally stable fixation of simulated sagittal split ramus osteotomy with 10 mm of advancement and to evaluate the screw insertion torque.

Effects of Androgen Deprivation Therapy on Pain Perception,Quality of Life,and Depression in Men With Prostate Cancer

Context

Previous animal and human research suggests that testosterone has antinociceptive properties. Castration in male rodents increases pain perception which is reversed by testosterone replacement. Pain perception also improves in hypogonadal men with testosterone therapy. However, it remains unclear whether androgen deprivation therapy (ADT) in men with prostate cancer (PCa) is associated with an increase in pain perception.

The Involvement of the Endocannabinoid System in the Peripheral Antinociceptive Action of Ketamine

Ketamine has been widely used as an analgesic and produces dissociative anesthetic effects. The antinociceptive effects of ketamine have been studied, but the involvement of endocannabinoids in these effects has not yet been investigated. In this study, we evaluated the involvement of the endocannabinoid system in the peripheral antinociceptive effects induced by ketamine. All drugs were administered via the intraplantar route. To induce hyperalgesia, rat paws were injected with prostaglandin E₂ (2?µg per paw). The nociceptive threshold for mechanical stimulation was measured in the right hind paw of Wistar rats using the Randall–Selitto test. The tissue levels of anandamide (AEA), 2-arachidonoylglycerol, palmitoylethanolamide, and oleoylethanolamide were measured using liquid chromatography coupled to single quadrupole mass spectrometry. The administration of the cannabinoid receptor type 1 (CB₁) antagonist, N(piperidine-1yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl 1 pyrazolcarboxamide (20, 40, and 80?µg per paw), but not the cannabinoid receptor type 2 antagonist, 6-iodo-2-methyl-1-(2-morpholinoethyl)-1H-indol-3-yl) (4-methoxyphenyl) methanone (100?µg per paw), antagonized the ketamine-induced peripheral antinociception in a dose-dependent manner. Additionally, the administration of the endocannabinoid metabolizing enzyme inhibitor (.5?µg per paw) or an AEA reuptake inhibitor, (5Z,8Z,11Z,14Z)N(4Hydroxy2methylphenyl)5,8,11,14 eicosatetraenamide (2.5?µg per paw) significantly enhanced low-dose ketamine-induced peripheral antinociception. AEA paw levels were increased only after ketamine administration to prostaglandin E₂-injected paws. These data suggest that ketamine, in the presence of a nociceptive stimulus, induces a selective release of AEA levels and subsequent CB₁ cannabinoid activation at the peripheral level.

Xylitol concentrations in artificial saliva after application of different xylitol dental varnishes

Objective

The present study analyzed xylitol concentrations in artificial saliva over time after application of varnishes containing 10% and 20% xylitol.

Material and Methods

Fifteen bovine enamel specimens (8x4 mm) were randomly allocated to 3 groups (n=5/group), according to the type of varnish used: 10% xylitol, 20% xylitol and no xylitol (control). After varnish application (4 mg), specimens were immersed in vials containing 500 µL of artificial saliva. Saliva samples were collected in different times (1, 8, 12, 16, 24, 48 and 72 h) and xylitol concentrations were analyzed. Data were assessed by two-way repeated-measures ANOVA (p<0.05).

Results

Colorimetric analysis was not able to detect xylitol in saliva samples of the control group. Salivary xylitol concentrations were significantly higher up to 8 h after application of the 20% xylitol varnish. Thereafter, the 10% xylitol varnish released larger amounts of that polyol in artificial saliva.

Conclusions

Despite the results in short-term, sustained xylitol releases could be obtained when the 10% xylitol varnish was used. These varnishes seem to be viable alternatives to increase salivary xylitol levels, and therefore, should be clinically tested to confirm their effectiveness.     

Effects of curing protocol and storage time on the micro-hardness of resin cements used to lute fiber-reinforced resin posts

Objectives

To determine the micro-hardness profile of two dual cure resin cements (RelyX - U100^®, 3M-ESPE and Panavia F 2.0^®, Kuraray) used for cementing fiber-reinforced resin posts (Fibrekor^® - Jeneric Pentron) under three different curing protocols and two water storage times.

Material and methods

Sixty 16mm long bovine incisor roots were endodontically treated and prepared for cementation of the Fibrekor posts. The cements were mixed as instructed, dispensed in the canal, the posts were seated and the curing performed as follows: a) no light activation; b) light-activation immediately after seating the post, and; c) light-activation delayed 5 minutes after seating the post. The teeth were stored in water and retrieved for analysis after 7 days and 3 months. The roots were longitudinally sectioned and the microhardness was determined at the cervical, middle and apical regions along the cement line. The data was analyzed by the three-way ANOVA test (curing mode, storage time and thirds) for each cement. The Tukey test was used for the post-hoc analysis.

Results

Light-activation resulted in a significant increase in the microhardness. This was more evident for the cervical region and for the Panavia cement. Storage in water for 3 months caused a reduction of the micro-hardness for both cements. The U100 cement showed less variation in the micro-hardness regardless of the curing protocol and storage time.

Conclusions

The micro-hardness of the cements was affected by the curing and storage variables and were material-dependent.     

Avulsion of globe following maxillofacial trauma

Avulsion of the eye globe is a rare condition that is unexpected in maxillofacial trauma and results from severe trauma to the orbit and face. A search of the literature reveals very few reported cases. The present article reports a case of this singular, challenging condition and comments on several other related causes, pathophysiology mechanisms, risks, complications, and management.