Bone and soft tissue changes associated with a removable partial denture. A novel method with a fusion of CBCT and optical 3D images.

BACKGROUND: The purpose of this study was to propose a novel method for 3D evaluation of bone and mucosal changes in removable partial denture (RPD) foundation area using a fusion of cone beam computed tomography (CBCT) and optical 3D images. METHOD: Two CBCT scans and three impressions, taken at insertion and after ten months of wearing the RPD, were acquired from five patients. 3D models of bone and surface were created from CBCT images and gypsum casts, respectively, spatially aligned and saved in Standard Tessellation Language file format. Visual and numerical analysis of differences between the models allows evaluation of surface, mucosal and bone changes in regions of interest (ROI) defined as narrow ROI (nROI), denture foundation area ROI (dROI) and wide ROI (wROI). Site-specific analysis was performed in mesiodistal and buccolingual direction. RESULTS: Visual evaluation of 3D color-coded deviation maps showed irregular distribution of bone and surface changes. The differences between mandibles and also between left and right sides were found. Mean volume of bone change in dROI was -135.86 (range = -456.18 to 21.20) mm3. The average bone change thickness in dROI was -0.26 (range = -0.96 to 0.07) mm. The mean volume changes in nROI were -38.31 (range = -118.26 to 45.87) mm3, -51.96 (range = -182.54 to 5.6) mm3 and 13.66 (range = -80.62 to 79.46) mm3 for surface, bone and mucosa, respectively. CONCLUSIONS: The proposed method facilitates separate visual and numerical evaluation of surface, mucosa and bone changes. It opens possibilities for a better understanding of denture-supporting tissues remodeling, objective evaluation and comparison of different treatment options.

Breast cancer upregulating genes in stromal cells by LINE-1 hypermethylation and micrometastatic detection.

UNLABELLED: Changes in the methylation level of genes containing LINE-1 alter host gene regulation. AIM: This study demonstrates that paracrine signaling of breast cancer influences the epigenetic regulation of stromal cells. METHODS: We proved in vitro and in vivo breast cancer promoted LINE-1 methylation exists exclusively in female stromal cells. RESULTS: Genes containing LINE-1 of breast cancer stromal cells were upregulated. Furthermore, one of the genes, MUC-1, was demonstrated to have expression in plasma cells from the lymph nodes of patients with lymph node metastasis or micrometastasis. CONCLUSION: Breast cancer sends a paracrine signal to stroma cells causing LINE-1 epigenetic regulation. Moreover, the regulated genes in stroma cells are potential biomarkers for detecting breast cancer micrometastasis.

Influence of denture supporting tissue properties on pressure-pain threshold--measurement in dentate subjects.

PURPOSE: The present study was designed to clarify the relationship between the properties of the palatal mucosa and the pressure-pain threshold. METHODS: Three parts of the palatal mucosa of 17 dentate subjects were measured: the median part of the palate, the lateral part of the first molar, and the midpoint between these two parts. The subjects were instructed to press a pushbutton when he or she felt pressure-pain. The probe pressure was gradually increased (1N/s). The thickness (T) (mm) and elasticity (E) (MPa) were used as the parameters of the properties of the palatal mucosa, whereas pressure (P) (MPa), compressibility (C) (%), and subsidence (S) (mm) were used as the parameters of the pressure-pain threshold. The Shapiro-Wilk test was used to consider the data of distribution of normality for each measurement point, as obtained from the 17 subjects. A Kruskal-Wallis test and a Wilcoxon signed rank test were performed for multiple comparisons, the Bonferroni method was used to compensate for the P-value. Spearman's rank correlation coefficient was calculated. RESULTS: T correlated with the values of S at the median points (P=0.001) and midpoints (P=0.011). CONCLUSION: Thickness can be an index of the amount of relief where pain is caused easily. In addition, modulus of elasticity is important as an indicator of the bearing ability of denture support tissues, it is necessary to consider how to evaluate the modulus of elasticity and to evaluate the relationship between the parameters of the pain threshold.

Photoelastic stress analysis of implants according to fixture design / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the pattern and the magnitude of stress distribution in the supporting tissues surrounding three different types of implants(ITI, 3i, and Bicon implant system). MATERIAL AND METHOD: Photoelastic models were made with PL-2 resin(Measurements Group, Raleigh, USA) and three implants of each kind were placed in the mandibular posterior edentulous area distal to the canine . For non-splinted restorations, individual crowns were fabricated on three titanium abutments. For splinted restorations, 3-unit fixed partial dentures were fabricated. Photoelastic stress analyses were carried out to measure the fringe order around the implant supporting structure under simulated loaded conditions(15 lb, 30 lb). CONCLUSION: The results were as follows; 1. Regardless of the implant design, stresses were increased in the apex region of loaded implant when non-splinted restorations were loaded. While relatively even stress distribution occurred with splinted restorations. Splinting was effective in the second implant. 2. Strain around Bicon implant were lower than those of other implants, which confirmed the splinting effect. The higher the load, the more the stress occurred in supporting tissue, which was most obvious in the Bicon system. 3. Stress distribution in the supporting tissue was favorable in the ITI system, while the other side of 3i system tended to concentrate the stress in some parts.

Photoelastic stress analysis of implants according to fixture design / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the pattern and the magnitude of stress distribution in the supporting tissues surrounding three different types of implants(ITI, 3i, and Bicon implant system). MATERIAL AND METHOD: Photoelastic models were made with PL-2 resin(Measurements Group, Raleigh, USA) and three implants of each kind were placed in the mandibular posterior edentulous area distal to the canine . For non-splinted restorations, individual crowns were fabricated on three titanium abutments. For splinted restorations, 3-unit fixed partial dentures were fabricated. Photoelastic stress analyses were carried out to measure the fringe order around the implant supporting structure under simulated loaded conditions(15 lb, 30 lb). CONCLUSION: The results were as follows; 1. Regardless of the implant design, stresses were increased in the apex region of loaded implant when non-splinted restorations were loaded. While relatively even stress distribution occurred with splinted restorations. Splinting was effective in the second implant. 2. Strain around Bicon implant were lower than those of other implants, which confirmed the splinting effect. The higher the load, the more the stress occurred in supporting tissue, which was most obvious in the Bicon system. 3. Stress distribution in the supporting tissue was favorable in the ITI system, while the other side of 3i system tended to concentrate the stress in some parts.

Effects of Release of Tip Supporting Fibrous Tissues for Short Nose Correction

A short nose is one that extends less than one third of the vertical height of the face or whose distance from nasion to tip-defining point is short. Lengthening short noses has been regarded as one of the most challenging and at times vexing tasks in secondary nasal surgery. For correction of short nose, nasal tip supporting tissues from alar cartilages are released and nasal tip is positioned and fixed again. There are five important nasal tip supporting tissues, fibrous connection between upper lateral cartilage and lower lateral cartilage, hinge region(fibrous connection between lateral border of lateral crus and pyriform aperture), interdormal attachment to anterior septal angle (fibrous tissue between anterior septal angle and middle crus), fibrous connection between septum and foot plate of medial crus and dermocartilaginous ligament. This study is to find out which one of the five nasal tip supporting tissues is the most important in short nose correction except dermocartilaginous ligament which has to be released during rhinoplasty. We dissected ten noses from ten fresh cadavers. Five were male and five were female with an average age of sixty three for all ten. We measured the distance between anterior septal angle and tip-defining point in every step of soft tissue dissection releasing the alar cartilage and mucosa, that are often released in short nose corrections and caudally pulling them to the direction of tip-defining point. First, distances were measured in resting and in pulling of alar cartilage. Further, changed distance were measured after releasing nasal tip supporting tissues beginning from the dissection of soft tissues between lateral crus and upper lateral cartilage to that of mucoperichondrium underneath upper lateral cartilage and septal mucoperichondrium. In each process, we found the average and standard variation, confirmed effects of those values to the lengthening of short noses. Dissecting upper lateral cartilage and lateral crus of alar cartilage was most effective in short nose correction. We also found it effective to release the hinge area and dissect the mucoperichondrium under upper lateral cartilage in lengthening the short noses.