Stress distribution prevents ischaemia and bone resorption in residual ridge

Objective

Intensive mechanical stress and/or inflammation are known to induce alveolar bone resorption. This study investigated whether a distribution of mechanical stress would reduce residual ridge resorption or improve ischaemia.

Design

Thirty rats were divided into six experimental groups (n = 5). The control group received no intentional stimulation, but rats in the experimental groups wore denture stimulators made of acrylic resin or a soft lining material. The stimulator transmitted masticatory pressure to the rats’ palates for four weeks. The four types of soft lining materials investigated in this study dispersed the applied pressure, with compressive stress ranging from 20.8 to 90.8 kPa. Volumes of blood flow and bone resorption of denture foundations were measured every week for 4 weeks. Statistical evaluation of these results was performed using two-way ANOVA and Holm-Sidak test within 5% error limits.

Results

Non-viscoelastic material clearly induced bone resorption and ischaemia of denture foundations, while viscoelastic materials reduced these phenomena to different extents according to their viscoelastic properties. Ischaemia in the alveolar ridge preceded residual ridge resorption, because the amount of residual ridge resorption and blood flow rate showed a simple linear regression.

Conclusion

Animal model of this study suggested that a distribution or reduction of mechanical stress could improve blood flow and decrease alveolar ridge resorption.     

Effect of adhesive primer developed exclusively for heat-curing resin on adhesive strength between plastic artificial tooth and acrylic denture base resin

Despite progress in the development of denture base resin and artificial tooth materials, dental clinics are still plagued with artificial teeth falling off the denture base--due to poor bond strength--after denture delivery. Against this background, this study sought to examine the effect and durability of an adhesive primer developed exclusively for heat-curing resin on the adhesive strength of heat-curing denture base acrylic resin to plastic artificial tooth. Test specimens were divided into four groups according to the treatment method of the artificial tooth's test bonding surface: air abrasion, adhesive primer application, adhesive primer application after air abrasion, and pretreatment only (control). After heat curing of acrylic resin onto the bonding surface, shear test was performed for two storage periods: 24-hour versus 100-day water storage. From the results obtained, it was revealed that the evaluated adhesive primer was significantly effective in increasing adhesive strength between artificial tooth and acrylic resin, although specimens were stored in water for 100 days.     

The combination of the serum carbohydrate antigen 19-9 and carcinoembryonic antigen is a simple and accurate predictor of mortality in pancreatic cancer patients

Purpose

The aim of this study was to detect high-performance prognostic biomarkers of pancreatic cancer which would enable the identification of high-risk patients.

Methods

The subjects were 324 patients who underwent radical surgery for pancreatic ductal adenocarcinoma without neoadjuvant therapy. We evaluated the prognostic impact of four perioperative serum tumor markers, including carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA). We also evaluated the indices by multiplying the values of two tumor markers (e.g., CA19-9 × CEA).

Results

The preoperative CA19-9 × CEA index had a strong correlation with the prognosis of patients with pancreatic cancer, even when the cut-off was set at the median value. CA19-9 × CEA ≥500 was an independent predictor of mortality (hazard ratio: 1.642, p = 0.021). In the ROC curve analysis of early mortality after surgery, the CA19-9 × CEA index had the highest goodness of fit. The presence of CA19-9 × CEA ≥500 had the largest attributable risk proportion because of its combined high predictive performance and prevalence. The postoperative CA19-9 × CEA index was also a significant predictive marker of mortality.

Conclusion

The CA19-9 × CEA index is a strong prognostic biomarker that could help identify pancreatic cancer patients expected to have a poor prognosis so that they can be administered appropriate multidisciplinary treatment.     

Combined anteversion technique reduced the dislocation in cementless total hip arthroplasty

Purpose

The combined anteversion (CA) technique is a method in which the cup is placed according to the stem anteversion in total hip arthroplasty (THA). We examined whether the CA technique reduced the dislocation rate, and the distribution of CA with the manual placement of the cup.

Methods

We retrospectively reviewed 634 hips in 579 patients with primary cementless THA. In 230 hips using the CA technique [CA(+)], a CA of 50 ± 10° was the aim. In the remaining 404 hips [CA(−)], the cup was first placed targeting 20° of anteversion. The post-operative CA was measured using the computed tomography (CT) images in 111 hips.

Results

One hip (0.4 %) had a dislocation in the CA(+) group, whereas ten hips (2.5 %) had a dislocation in the CA(−) group. A multivariate analysis showed that primary diagnosis, head size and CA technique significantly influenced the dislocation rate. Patients in the CA(−) group were 5.8 times more likely to have a dislocation compared to the CA(+) group. In the 111 hips with CT images, 81 hips (73.0 %) achieved the intended CA.

Conclusions

Although the manual placement of the cup resulted in 27 % of outliers from the intended CA, the CA technique significantly reduced the dislocation after primary THA.     

Sports Participation in Patients After Total Hip Arthroplasty vs Periacetabular Osteotomy: A Propensity Score-Matched Asian Cohort Study

Background

No studies have compared sports participation between total hip arthroplasty (THA) and periacetabular osteotomy (PAO) in matched Asian cohorts. We investigated sports participation and activity levels in Asian THA cohort, and compared them between THA and PAO cohorts.

Left ventricular assist device implantation after plasma exchange for heparin-induced thrombocytopenia

Treating a patient with heparin-induced thrombocytopenia can be challenging particularly when the patient requires urgent cardiac surgery that uses heparin for anticoagulation. We herein report a case of a 61-year-old man with idiopathic dilated cardiomyopathy associated with heparin-induced thrombocytopenia and who underwent plasma exchange to remove heparin-induced thrombocytopenia antibodies before undergoing left ventricular assist device implantation. The surgery was performed using cardiopulmonary bypass and unfractionated heparin.