Healing and osseointegration of submerged microtextured oral implants

The success of dental implants is primarily dependent upon the degree of osseointegration or bone-to-implant contact (BIC), possibly facilitated by a roughened implant surface. This study was performed to histologically evaluate the nature of osseointegration and bone healing of submerged microtextured implants in eight dogs. Three months following tooth extraction in the posterior mandibulae, three microtextured submerged implants were placed in each quadrant. Block biopsies were harvested at 4 and 16 weeks (four dogs each) following surgery, and histologic preparation was performed. Histomorphometric analysis demonstrated that % BIC value increased marginally from 40% at 4 weeks to 48% at 16 weeks, without a statistically significant difference. The first bone-to-implant contact (f-BIC) at 16 weeks was significantly lower than the 4-week f-BIC (0.81 mm vs. 0.56 mm). In conclusion, this study found minimal change in BIC over time (from 4 to 16 weeks) in unloaded microtextured implants, while the mean f-BIC value significantly increased during this same observation period.     

Carbon paste electrodes of the mixed oxide SiO2/Nb2O5 prepared by the sol–gel method: dissolved dioxygen sensor

A carbon paste of SiO₂/Nb₂O₅ material was used as the electrode in the development of a dissolved dioxygen sensor in 1.0 mol l^?1 KCl solution at pH 6.2. The material was prepared by the sol–gel method. In the investigation of its electrochemical properties, linear and cyclic voltammetric and chronoamperometric techniques were employed. Dioxygen reduction, which was diffusion controlled, occurred at ?280 mV vs. SCE by a two electron mechanism, producing peroxide. A linear response between the cathodic peak current intensity and the dissolved O₂ concentration was obtained for the region between 1.0 and 13.6 mg l^?1. The stability proved to be very good over successive voltammetric cycles. The electrode response time was about 5 s. The electron transfer reactions were explained as being to an n-type semiconductor of niobia dispersed in the silica surface.     

False aneurysm of the facial artery

A case of an unusual traumatic aneurysm of the facial artery secondary to blunt trauma is reported. The lesion was typical in that it was pulsatile, had a systolic bruit, and had a filling defect that was evident on carotid angiography. Although a traumatic aneurysm is a rare occurrence in the facial region, the inclusion of this lesion in the differential diagnosis of soft tissue lesions is important if the serious consequences of hemorrhage are to be avoided.     

Education of dentists in China

China is geographically located in the east of Asia and its population exceeds 1.3 billion. An understanding of dental education in China is thus of interest. However, as there is little published information on this topic, this paper provides information about China regarding its dental history, dental school system including curriculum and dental licensure. High school graduates take a nationwide entrance examination to apply for dental school, of which there are more than 50 in China. A five year dental education leads to the BDS degree. Dental school graduates must then pass the nationwide licensure examination to practise dentistry. Currently, there are not adequate numbers of dentists to provide the necessary oral health care for people living outside metropolitan areas.     

Safety and efficacy of a nightguard bleaching agent containing sodium fluoride and potassium nitrate.

OBJECTIVES: Transient sensitivity during bleaching is generally reported to affect 67% of patients. While most people tolerate this sensitivity, some find it impossible to continue treatment. The purpose of this study was to determine the safety and efficacy of an experimental, low-sensitivity bleaching agent. METHOD AND MATERIALS: Twenty-two participants bleached for a minimum of 6 hours per night over a 2-week period. The bleaching agent used, Experimental Product E, is a 10% carbamide peroxide gel containing potassium nitrate and sodium fluoride. Evaluations were performed at baseline and 1,2,13, and 26 weeks. Color change was measured using a value-ordered Vita classic shade guide and a colorimeter. Sensitivity of the teeth, gingiva, tongue, and/or throat was measured daily using a patient log. RESULTS: The median color change after 2 weeks was eight tabs. Approximately 36% reported sensitivity during the active whitening phase of the study. As a group, participants reported sensitivity during 13.7% of the total days spent whitening. CONCLUSION: Experimental Product E was shown to be safe. Participants experienced minor sensitivity during the active bleaching phase only. Experimental Product E was shown to be an effective bleaching agent for the subjects tested in this study.     

North American dental students' perspectives about their clinical education

Many North American dental schools face the challenge of replacing the majority of their "boomer generation" clinical instructors over the next ten years as this cohort of faculty reaches retirement age. Developing a new cadre of clinical instructors poses a substantial faculty development challenge: what instructional techniques should be integrated into routine educational practice by the dental faculty of the future, and what aspects of the clinical learning environment should be addressed to improve the overall quality of the experience for patients, students, and the new cohort of instructors? To gain insight that might guide faculty development for new clinical instructors and enhance understanding of the learning environment in dental school clinics, this study addressed the following question: what are dental students' perceptions of their learning experiences in the clinical setting? The purpose of the study was to evaluate the effectiveness of the clinical instruction from the perspectives of the actual "consumer" of dental education: the student. This consumers' perspective was provided by 655 junior, senior, and graduate dental students at twenty-one North American dental schools who completed the Clinical Education Instructional Quality Questionnaire (ClinEd IQ) in 2003-04. The ClinED IQ examines four components of students' clinical experiences: 1) clinical learning opportunities, 2) involvement in specific learning activities, 3) interaction with clinical instructors, and 4) personal perceptions about clinical education. With the exception of inconsistent feedback and instruction and lack of continuous contact with the same instructors, juniors, seniors, and graduate students rated their interaction with clinical instructors favorably (mean=4.76 on a 6.00 scale), but provided lower ratings for clinical learning opportunities (mean=4.26 on a 6.00 scale) due to concerns about the efficiency of the dental clinic environment and lack of opportunity to treat patients in a variety of clinical settings. Analysis of more than 1,000 written comments provided by these students indicated four areas of concern: 1) inconsistent and sometimes insensitive (patronizing, rude) feedback from faculty; 2) excessive amounts of noneducational "legwork" such as billing, patient scheduling, phone calling, completing paperwork, and performing other clinic operations tasks; 3) limited access to faculty because of insufficient numbers of instructors on the clinic floor or difficulty locating faculty when they were needed for coaching, work evaluation, and chart signatures; and 4) concerns about the strategies employed to meet procedural requirements that some students saw as ethically questionable. Junior, senior, and graduate dental students at twenty-one North American dental schools perceived that the strongest aspect of their clinical education was their relationship with the faculty, but also reported that the dental school clinic was often an inefficient learning environment that hindered their opportunity to develop clinical competency. Students also sensed that faculty shortages, a growing crisis for dental education, hindered their progress in the clinic and made learning less efficient.