Catastrophizing, anxiety and pain during dental hygiene treatment

Objectives : This study examined the relations between catastrophizing, dental anxiety, and pain during dental hygiene treatment. Methods: Participants were 78 (32 men, 46 women) consecutive referrals to the Dalhousie University Dental Clinic. All patients were scheduled for a scaling procedure performed by senior dental hygiene students. Following treatment, patients completed the Pain Catastrophizing Scale and the Dental Anxiety Scale – Revised, and were asked to rate the degree of pain they experienced during the scaling procedure. Results: Regression analyses revealed that age and the rumination subscale of the Pain Catastrophizing Scale were signicant predictors of pain, even when controlling for gender, and oral hygiene status. Conclusions: Thendings suggest that excessive focus on pain sensations may be one of the mechanisms by which catastrophizing leads to increased pain. The clinical challenges will be to develop cost- and time-effective means of identifying individuals who catastrophize and to implement interventions to reduce their level of distress.     

An investigation of some food-approved polymers as agents to inhibit hydroxyapatite dissolution

Dental erosion involves dissolution of the hydroxyapatite fraction of enamel and dentine, so agents that reduce the dissolution rate of hydroxyapatite could find application in food products aimed at reducing erosion. This study was performed to test some common food ingredients and additives for their effect on the dissolution rate of hydroxyapatite in a citric acid solution representative of soft drinks. Pyrophosphate, tripolyphosphate and a linear chain polyphosphate (average 25 phosphate units) significantly reduced the hydroxyapatite dissolution rate by 35, 46 and 64%, respectively. Xanthan gum and carboxymethylcellulose significantly reduced the hydroxyapatite dissolution rate by 29 and 16%, respectively. The protective effect may be ascribed to the binding of condensed phosphate or to the formation of an adsorbed layer of gum at the hydroxyapatite surface. Several other common food additives had no statistically significant effect on the hydroxyapatite dissolution rate. Polyphosphate exhibited a considerable persistence of action, causing a reduction in the dissolution rate for 3 h after treatment. Tripolyphosphate was slightly persistent, and pyrophosphate and xanthan gum did not exhibit a substantial persistence of action. A solution containing polyphosphate and xanthan gum reduced the hydroxyapatite dissolution rate by 70% and exhibited a similar persistence of action to the solution containing only polyphosphate. These compounds are suggested to have potential as erosion-reducing agents in soft drinks.     

Dental abnormalities and bone lesions associated with familial adenomatous polyposis: report of cases

Dental abnormalities and bone lesions of the maxilla and mandible are found in more than 70% of patients with familial adenomatous polyposis (FAP). Dental abnormalities include impacted teeth (other than third molars), supernumerary teeth, congenitally missing teeth, and fused roots of molars. Bone lesions consist of osteomas--isolated or in clusters--in the maxilla and mandible. In this study of 24 patients, 75% had demonstrable dental abnormalities, and 79% had osteomas of the maxilla and mandible. Because dental abnormalities and bone lesions are present early in life, these features may be helpful in diagnosing this syndrome.     

Serum levels of sclerostin,Dickkopf-1, and secreted frizzled-related protein-4 are not changed in individuals with high bone mass causing mutations in LRP5

Summary

We compared circulating levels of Wnt inhibitors among patients with high bone mass mutations in LRP5, unaffected kindred, and unrelated normal controls. Inhibitors were unchanged in affected and unaffected kindred. We saw no meaningful differences between controls and affected individuals. LRP5 signaling may not influence circulating levels of these inhibitors.

Introduction

It is thought that gain-of-function mutations in LRP5 result in high bone mass syndromes because these allelic variants confer resistance to the actions of endogenous inhibitors of Wnt signaling. We therefore attempted to determine if circulating levels of Wnt inhibitors are altered in patients with gain-of-function mutations in LRP5.

Methods

This is a cross-sectional study in a university research center. Serum was collected from consented volunteers known to have either the G171V or N198S gain-of-function mutations in LRP5, kindred members affected with either mutation, unrelated kindred, and unrelated normal age-matched controls. BMD was provided or measured on site.

Results

There were no significant differences found in the serum levels of sclerostin (SOST), Dickkopf-1 (Dkk-1), or secreted frizzled-related protein-4 (SFRP-4) in affected vs. unaffected individuals from different kindreds or when compared to age-matched unrelated normal individuals. Mean serum SOST values in affected and unaffected kindred members and unrelated normal controls were 52.7?±?6.1, 36.5?±?9.6, and 54.8?±?5.4, respectively. For Dkk-1, the values were 25.9?±?3.4, 25.7?±?3.0, and 17.3?±?2.3 and for SFRP-4, 38.1?±?2.3, 39.8?±?3.6, and 28.5?±?1.7. Serum levels of RANKL and osteoprotegerin (OPG) were not different in the three groups.

Conclusions

Circulating levels of endogenous Wnt inhibitors do not change in patients with gain-of-function mutations in LRP5 including Dkk1, which is suppressed by Wnt signaling. It may be that circulating levels of Wnt inhibitors do not reflect changes in target tissues. It is also possible that other mechanisms besides or in addition to resistance in Wnt inhibitors explains the skeletal effects of these mutations.     

Regional Myocardial Blood Flow

A method is described which measures the local effectiveness of the myocardial circulation, expressed as a clearance constant. Uniform clearance constants have been demonstrated in the normal canine and human myocardium. A distinct difference in clearance constants has been demonstrated between the normal canine myocardium and areas of naturally occurring disease. Heterogeneous clearance constants have been found in a majority of human subjects with coronary artery disease-the lowest rates being noted in areas of fibrous aneurysm.     

Cool Mist Irrigation Improves Heat Dissipation during Surgical Bone Drilling

Objective High-speed drilling generates heat in small cavities and may pose a risk for neurovascular tissues. We hypothesize that a continuous pressurized cold mist could be an alternative approach for better cooling during drilling of bone to access cranial lesions. This study aims to examine this idea experimentally. Design Ex-vivo drilling tests with controlled speed, feed, and depth were performed on cortical bone samples. Thermocouples were embedded underneath the drilling path to compare the temperature rises under mist cooling (at 3°C, < 300 mL/h) and flood irrigation (at 22°C, > 800 mL/h). Results A significant difference exists between these two systems (p value < 0.05). The measured temperature was ∼ 4°C lower for mist cooling than for flood irrigation, even with less than a third of the flow rate. Conclusion Experimental data indicate the capability of mist cooling to reduce heat generation while simultaneously enabling flow reduction and targeted cooling. An improved field of view in an extremely narrow access corridor may be achieved with this technology.