Exposure of Barriers Used in GBR: Rate, Timing, Management, And Its Effect on Grafted Bone. A Retrospective Analysis

The purpose of this study is to compare exposure rate of three different barrier types after a guided-bone regenerationprocedure, as well as to compare the percentage grafted bone dimensional loss with and without exposed barriers. Patient records from September 2007 to May 2015 were reviewed to identify subjects that had received bone graft and then implant placement procedure after the graft is completely healed. The subjects were divided into 3 groups: 1) resorbable barrier 2) non-resorbable barrier, and 3) titanium-mesh barrier. Incidences of barrier exposure were recorded. Cone-beam computed tomography images before treatment (T0), right after grafting (T1), and after healing (T2) were used to determine percentage grafted bone dimensional loss (%) and quantitative grafted bone remained (mm 2 ). Three cross-sectioned areas, at 1mm apart, of preplanned implant positions at the grafted site were measured on cone-beam computed tomography to calculate for grafted bone remained and grafted bone dimensional change. The exposure rate of all guided bone regeneration was 36.9%. Exposure rate of resorbable barrier (23.3%) is significantly lower than Titanium mesh (68.9%) and Non-resorbable (72.7%) (Chi-Square, P < .001). The result from this study revealed that barrier types have significant effect on exposure rate. There was also a significant different in grafted bone dimensional loss in sites with barrier exposure (58.3%) and sites with no barrier exposure (44.1%) during the healing period (Mann-Whitney U, P = .008).

Maxillary Implant Placement in a Limited Residual Bone Height

The limitation of residual bone height (RBH) and vital structures such as sinuses in the maxillary often make the implant placement procedure becomes complicated. Clinicians may perform sinus elevation prior to implant placement to accommodate the length of the implant fixture. Sinus elevation is an invasive procedure and complication may occur during the surgery including the most frequent complication is perforation of Schneiderian membrane. Objectives: To discuss a comprehensive management of implant placement and its complication step by step from surgical procedures to crown placement Case Report: 67-year-old female patient with partial edentulism in the right maxillary region, presence of sinus septum, and RBH was 4mm. The patient was planned to do sinus elevation surgery prior to implant placement, perforation of the Schneiderian membrane occurred while surgery performed and pericardium membrane was attached around the perforation site. Sinus re-entry and implant placement were performed after 3 months followed by prosthetics procedures in the next 6 month. Conclusion: Dental implant is a complicated treatment and complication may occur during the placement, thus a comprehensive management is very essential to minimize the risk of complications.

Pain Experience after Dental Implant Placement Compared to Tooth Extraction

Background. A patients’ main concern when visiting the dentist is the pain experience during the procedure and postoperatively. Patients who are undergoing dental surgical procedures in particular may experience more concerns and higher level of anxiety and stress that can affect their psychology and decision-making ability. A thorough discussion with the patients about the planned surgical procedure and the expected postsurgical pain and discomfort level is crucial to reduce their fear and stress. Despite increasing popularity of dental implants, limited data are available on pain experience related to surgical implant placement. This review is to discuss and compare postoperative pain and discomfort level after dental implant placement procedure and tooth extraction. The review has a clinical significance as it can be used as a reference when explaining to the patients about the anticipated pain and discomfort level after implant placement. Conclusion. Informing patients about implant placement surgical procedure and the anticipated postsurgical pain can reduce their anxiety level and affect postsurgical pain and discomfort. Implant placement surgical procedure is less unpleasant than tooth extraction, with less postsurgical pain and limitation of daily activities.

Optimal sensor placement for variational data assimilation of unsteady flows past a rotationally oscillating cylinder

An optimal sensor placement procedure is proposed within the framework of variational data assimilation (DA) for unsteady flows, with the aim of maximizing the efficiency of the DA procedure. It is dedicated to the a priori design of a sensor network, and relies on a first-order adjoint approach. The proposed methodology first consists in identifying, via optimal control, the locations in the flow that have the greatest sensitivity with respect to a change in the initial condition, boundary conditions or model parameters. In a second step, sensors are placed at these locations for DA purposes. The use of this optimal sensor placement procedure does not require extra development in the case where a variational DA suite is available. The proposed methodology is applied to the reconstruction of unsteady bidimensional flows past a rotationally oscillating cylinder. More precisely, the possibilities of reconstructing the rotational speed of the cylinder and the initial flow, which here encompasses upstream conditions, from various types of observations are investigated via variational DA. Then, the observation optimization procedure is employed to identify optimal locations for placing velocity sensors downstream of the cylinder. Both reduction in the computational cost and improvement in the quality of the reconstructed flow are achieved through optimal sensor placement, encouraging the application of the proposed methodology to more complex and realistic flows.