Practitioner and patient perceptions of orthodontic treatment: is the patient always right?

PURPOSE: As dentists embrace evidence-based clinical practice, we place increased emphasis on patient values. Standards like Angle Classification are not related to patient perceptions of the tangible benefits of treatment. This study quantifies the differences dentists and patients perceive in orthodontic treatment outcome. MATERIALS AND METHODS: A survey is used to quantify a patient's perception of orthodontic treatment. It was completed by 30 patients who completed treatment at the University of Pittsburgh School of Dental Medicine. Their responses were compared with the perceptions of five orthodontists, three general dentists, and two prosthodontists. RESULTS: Multivariate analysis of variance found the differences between and within the subjects to be significant at p < 0.004. Univariate analysis of variance of the initial scores showed the data to be significant at p < 0.002 and pairwise comparisons showed significant mean differences. Final score analysis of variance was significant at p < 0.001 and pairwise comparison showed significant mean differences. CONCLUSIONS: Patients and general dentists have a significantly less favorable initial perception of their dental esthetics and function when compared with orthodontists. Final scores of esthetic and functional perceptions between the patients and all three dentist groups showed significant differences, with patients perceiving the results of their treatment more favorably than practitioners. CLINICAL SIGNIFICANCE: The data herein elucidates differences in the value systems of professionals and patients. It is meant to encourage dentists to consider whether these differences justify the persistence of traditional orthodontic treatment goals or if treatment planning should incorporate consideration of each individual patient's preferences to maximize utility.

Human masseter muscle fiber type properties, skeletal malocclusions, and muscle growth factor expression.

PURPOSE: We identified masseter muscle fiber type property differences in subjects with dentofacial deformities. PATIENTS AND METHODS: Samples of masseter muscle were collected from 139 young adults during mandibular osteotomy procedures to assess mean fiber areas and percent tissue occupancies for the 4 fiber types that comprise the muscle. Subjects were classified into 1 of 6 malocclusion groups based on the presence of a skeletal Class II or III sagittal dimension malocclusion and either a skeletal open, deep, or normal bite vertical dimension malocclusion. In a subpopulation, relative quantities of the muscle growth factors IGF-I and GDF-8 gene expression were quantified by real-time polymerase chain reaction. RESULTS: Fiber properties were not different in the sagittal malocclusion groups, but were very different in the vertical malocclusion groups (P ≤ .0004). There were significant mean fiber area differences for type II (P ≤ .0004) and type neonatal-atrial (P = .001) fiber types and for fiber percent occupancy differences for both type I-II hybrid fibers and type II fibers (P ≤ .0004). Growth factor expression differed by gender for IGF-I (P = .02) and GDF-8 (P < .01). The ratio of IGF-I:GDF-8 expression associates with type I and II mean fiber areas. CONCLUSION: Fiber type properties are very closely associated with variations in vertical growth of the face, with statistical significance for overall comparisons at P ≤ .0004. An increase in masseter muscle type II fiber mean fiber areas and percent tissue occupancies is inversely related to increases in vertical facial dimension.

Intracellular trafficking pathways involved in the gene transfer of nano-structured calcium phosphate-DNA particles.

Nano-structured calcium phosphate (NanoCaP) particles have been proven to be a powerful means of non-viral gene delivery. In order to better understand the mechanisms through which NanoCaPs-mediated mammalian cell transfection is achieved, we have sought to define the intracellular trafficking pathways involved in the cellular uptake and intracellular processing of these particles. Previous work has indicated that NanoCaP-DNA complexes are most likely internalized via endocytosis, however the subsequent pathways involved have not been determined. Through the use of specific inhibitors, we show that endocytosis of NanoCaP particles is both clathrin- and caveolae-dependent, and suggest that the caveolaer mechanism is the major contributor. We demonstrate colocalization of NanoCaP-pDNA complexes with known markers of both clathrin-coated and caveolar vesicles. Furthermore, through the use of quantitative flow cytometry, we present the first work in which the percent internalization of CaP-DNA complexes into cells is quantified. The overall goal of this research is to foster the continued improvement of NanoCaP-based gene delivery strategies.

Cytochrome c oxidase deficiency in human posterior cricoarytenoid muscle.

BACKGROUND: Mitochondrial alterations occur in skeletal muscle fibers throughout the normal aging process, resulting from increased accumulation of reactive oxide species (ROS). These result in respiratory chain abnormalities, which decrease the oxidative capacity of muscle fibers, leading to decreased contractile force, sarcopenia, or fiber necrosis. Intrinsic laryngeal muscles are a cranial muscle group that possesses some distinctive genotypic, phenotypic, and physiologic properties. Their susceptibility to mitochondrial alterations resulting from biological processes that increase levels of oxidative stress may be one of these distinctive characteristics. OBJECTIVES: The incidence of cytochrome c oxidase (COX) deficiency (COX(-)) was determined in human posterior cricoarytenoid (PCA) muscle when compared with the human thyrohyoid (TH) muscle, an extrinsic laryngeal muscle that served as "control" muscle. Ten PCA and 10 TH muscles were harvested postlaryngectomy from 10 subjects ranging in age from 55 to 86 years. Differences in COX(-) were compared within and between muscle types using tissue section staining and standard morphometric analysis. RESULTS AND CONCLUSIONS: COX(-) fibers were identified in both the PCA and TH muscles. The PCA muscle had 10 times as may affected fibers as the TH muscle, with significant differences in COX(-) found between muscle type and fiber type (P=0.003). Almost all of this effect was the result of elevated levels of COX(-) in type I fibers from the PCA muscle (P=0.002) that showed a strong positive correlation with increased age. These results suggest that increased mitochondrial alterations may occur in the PCA muscle during normal aging.

In-vitro evaluation of frictional resistance with 5 ligation methods and Gianelly-type working wires.

INTRODUCTION: Numerous in-vitro studies have been conducted with various archwire-ligation combinations to evaluate the effect of wire size and ligation method on frictional resistance. The aim of this in-vitro study was to compare the frictional resistance during sliding mechanics with Gianelly-type stainless steel working wires, Leone slide ligature, conventional elastic ligature, and stainless steel (SS) ligature, and a conventional bracket and active and passive self-ligating brackets. METHODS: Three ligation methods with Victory (V) brackets--Leone (VLeone), conventional (regular) elastic (VReg), and SS (VSS)--were used with standard SS brackets, and 2 self-ligating brackets--Damon MX (Ormco/"A", St. Paul, Minn) (DMX) and In-Ovation R (GAC Intl., Bohemia, NY)--were used with 2 rectangular SS wires (0.016 x 0.022 and 0.018 x 0.022 in). Therefore, 5 ligation methods and 2 wire sizes were evaluated with respect to their effects on frictional resistance. RESULTS: No statistically significant differences were found between the SS ligation method and DMX (neither produced measurable static friction). For the wire size 0.016 x 0.022-in SS, the DMX and SS produced significantly less static friction than the In-Ovation R, VLeone, and VReg. The In-Ovation R produced significantly less friction than both the VLeone and VReg, whereas the VLeone produced significantly less friction than the VReg. For the wire size 0.018 x 0.022-in SS, the overall results were the same, except that the In-Ovation R produced significantly more friction than the VLeone. An increase in wire size (from 0.016 x 0.022 to 0.018 x 0.022 in) led to an increase in friction in all bracket-archwire combinations (except DMX and VSS, which showed no measurable friction at either wire size). CONCLUSIONS: The Leone slide ligature showed less friction at both wire sizes than VReg; however, it showed significantly more friction than both DMX and VSS. DMX and VSS brackets produced no measurable friction with either 0.016 x 0.022-in or 0.018 x 0.022-in wires. An increase in wire size (from 0.016 x 0.022 to 0.018 x 0.022 in) led to an increase in friction in all bracket-archwire combinations (excluding DMX and VSS, which showed no measurable friction at either wire size).

Complications associated with anesthesia administration for dental treatment in a special needs clinic.

The goal of this study was to identify and quantify complications occurring with the administration of anesthesia for the dental treatment of patients with special needs. Anesthesia providers completed a standardized evaluation form, delineating possible complications for 202 consecutive ambulatory patients receiving anesthesia in a special needs clinic. Statistical analysis of four types of administered anesthesia showed that the overall complication rate was 23.8%. Evaluation of the data showed complications that were considered either mild (95.8%), or moderate (4.2%), while no reports of severe complications occurred. Airway obstruction and nausea/vomiting were the most frequently encountered complications. Variables found to affect the incidence of anesthetic complications included ASA classification, anesthetic technique, Mallampati airway classification, and type of dental procedure performed. An evaluation of the results of the study showed that the majority of complications that occurred with anesthesia during care of patients with special needs were mild and did not lead to severe adverse events. Our findings show that anesthesia administered during dental treatment for patients with special needs is safe and effective.

Sialadenosis in patients with advanced liver disease.

Sialadenosis (sialosis) has been associated most often with alcoholic liver disease and alcoholic cirrhosis, but a number of nutritional deficiencies, diabetes, and bulimia have also been reported to result in sialadenosis. The aim of this study was to determine the prevalence of sialadenosis in patients with advanced liver disease. Patients in the study group consisted of 300 candidates for liver transplantation. Types of liver disease in subjects with clinical evidence of sialadenosis were compared with diagnoses in cases who had no manifestations of sialadenosis. The data were analyzed for significant association. Sialadenosis was found in 28 of the 300 subjects (9.3%). Among these 28 cases, 11 (39.3%) had alcoholic cirrhosis. The remaining 17 (60.7%) had eight other types of liver disease. There was no significant association between sialadenosis and alcoholic cirrhosis (P = 0.389). These findings suggest that both alcoholic and non-alcoholic cirrhosis may lead to the development of sialadenosis. Advanced liver disease is accompanied by multiple nutritional deficiencies which may be exacerbated by alcohol. Similar metabolic abnormalities may occur in patients with diabetes or bulimia. Malnutrition has been associated with autonomic neuropathy, the pathogenic mechanism that has been proposed for sialadenosis.

Endobronchial ultrasound as a diagnostic tool in patients with mediastinal lymphadenopathy.

BACKGROUND: The diagnostic yield and accuracy of new approaches to diagnose cancer should focus on comparison with established surgical techniques. Our objective was to evaluate the diagnostic performance of endobronchial ultrasound (EBUS) to detect cancer in patients with radiographically abnormal mediastinal lymph nodes. METHODS: The medical records of patients who underwent EBUS and had abnormal mediastinal lymph nodes (short-axis >1 cm and [or] positron emission topography-positive) over a 25 month period at the University of Pittsburgh were reviewed. Demographic and clinical data, cytology, and pathology results were entered in a database and analyzed. RESULTS: A total of 172 patients [male to female = 1.8:1; median age, 67 years (range, 20 to 90]) were included. The diagnostic yield of EBUS cytology was 79.7% (137 of 172). Pathologic testing was available in 68% (117 of 172) and 82% (96 of 117) had a diagnostic EBUS. The diagnostic accuracy of EBUS was 91.7%. The sensitivity, specificity, positive (PPV) and negative (NPV) predictive values were 88.1% (95% confidence interval [CI], 77.3 to 94.3), 100% (95% CI, 85.9 to 100), 100% (95% CI, 92.4 to 100), and 80.6% (95% CI, 63.4 to 91.2), respectively. In 67 patients who had a suspected or biopsy-proven primary lung cancer, diagnostic yield was 86.6% and accuracy was 94.8%. In this subgroup the sensitivity, specificity, PPV, and NPV were 93% (95% CI, 76.5 to 98.9), 100% (95% CI, 69.9 to 100), 100% (95% CI, 85 to 100), and 83.3% (95% CI, 56.2 to 97.5). CONCLUSIONS: Diagnostic performance data support the clinical usefulness of EBUS in the evaluation of patients with a radiographically abnormal mediastinum. It should be considered complementary to mediastinoscopy rather than substitutive.

Should endobronchial ultrasonography be part of the thoracic surgeon's armamentarium?

OBJECTIVE: The study objective was to determine the clinical usefulness and accuracy of endobronchial ultrasound-guided needle aspiration of mediastinal and hilar lymph nodes. METHODS: A retrospective analysis of a thoracic surgery unit's experience was performed. RESULTS: In a period of 19 months, 75 patients underwent the procedure (mean age = 65.5 +/- 1.6 years; male to female = 2:1) most commonly for mediastinal lymphadenopathy in the setting of diagnosed or suspected lung cancer. It was diagnostic in 68.9% after rapid on-site evaluation and 74.3% after final cytologic examination. The rapid on-site evaluation and final cytology results were discordant in 16.2% (P < .001). In 50 cases, the needle aspirate cytology could be compared with pathology results. The sensitivity and specificity for the diagnosis of cancer were 85% and 100%, respectively. The false-negative rate endobronchial ultrasound cytology was 8.1%. Mediastinal lymph node station 7 was most commonly biopsied. The stations with the highest diagnostic yield were: 11R, 3, 10L, and 7. Of the patients with a positive positron emission tomography scan with suspected clinical stage III lung cancer, cancer was downstaged in 40% after endobronchial ultrasound. CONCLUSION: Endobronchial ultrasound-guided needle aspiration is a clinically useful minimally invasive option for lung cancer staging and evaluation of mediastinal lymphadenopathy. The procedure should be considered complementary to mediastinoscopy.

Exploring dental students' perceptions of cultural competence and social responsibility.

The improvement of basic cultural competency skills and the creation of a greater community-minded spirit among dental students are important parts of dental education. The purpose of our study was to assess changes in dental students' attitudes and beliefs about community service and changes in cultural competencies after participation in a two-year program of non-dental community service (Student Community Outreach Program and Education, SCOPE). During 2003-07, two identical twenty-eight-item surveys were administered to SCOPE participants/completers. In the first, students reported on their attitudes after program completion. In the second, students reported retrospectively on their attitudes prior to starting the program. One hundred twenty-six post- and pre-intervention surveys were matched and assessed for changes in student attitudes after program participation. Based on factor analysis, four distinct scales were identified: 1) community service, 2) cultural competence, 3) communication, and 4) treatment perspective. Over time, statistically significant changes (p<.05) in student attitudes and beliefs were found for scales 1 (p=.017), 2 (p=.001), and 3 (borderline significance, p=.057). Scale 4 showed no significant difference (p=.108). These scales indicate main focus areas to help guide future dentists in acquiring relevant sociocultural competencies and enabling community-minded attitudes. Overall, this study provides support for the addition of a non-dental community service-learning program into the preclinical curriculum.

Redefining the biologic width in severe, generalized, chronic periodontitis: implications for therapy.

BACKGROUND: Previous studies demonstrated significant variability in the histologic biologic width in periodontal health and mild periodontitis. The purpose of this study was to determine whether the previously established dimensions of the biologic width applied to subjects with severe, generalized, chronic periodontitis. METHODS: Twenty-eight subjects, aged 29 to 45 years, with severe, generalized, chronic periodontitis were included in the study. There were 18 males and 10 females, and 19 (68%) of the patients were smokers. Clinical and radiographic measures were taken by calibrated examiners. The clinical biologic width was determined from the most coronal level of clinical attachment to the crest of the alveolar bone for proximal surfaces only and compared to the histologic biologic width previously reported. RESULTS: The clinical biologic width in subjects with severe, generalized periodontitis was significantly greater than previously reported (P <0.001). For all evaluable proximal sites, the mean clinical biologic width was 3.95 mm versus the mean histologic biologic width of 2.04 mm. The greatest clinical biologic widths were seen with pockets <2 mm (5.02 +/- 2.48 mm; range: 1.60 to 9.00 mm) and 2 to 4 mm (4.16 +/- 1.32 mm; range: 0.20 to 6.40 mm). CONCLUSIONS: The mean clinical biologic width in subjects with severe, generalized, chronic periodontitis seemed to be significantly greater than the histologic biologic width previously reported for subjects not demonstrating significant periodontal pathology. In addition, sites with shallow probing depths demonstrated the greatest biologic width, suggesting that these sites may be at increased risk for losing clinically significant attachment during surgical procedures.

Quantification of myosin heavy chain RNA in human laryngeal muscles: differential expression in the vertical and horizontal posterior cricoarytenoid and thyroarytenoid.

BACKGROUND: Human laryngeal muscles are composed of fibers that express type I, IIA, and IIX myosin heavy chains (MyHC), but the presence and quantity of atypical myosins such as perinatal, extraocular, IIB, and alpha (cardiac) remain in question. These characteristics have been determined by biochemical or immunohistologic tissue sampling but with no complementary evidence of gene expression at the molecular level. The distribution of myosin, the main motor protein, in relation to structure-function relationships in this specialized muscle group will be important for understanding laryngeal function in both health and disease. OBJECTIVES: We determined the quantity of MyHC genes expressed in human posterior cricoarytenoid (PCA) and thyroarytenoid (TA) muscle using real-time quantitative reverse-transcriptase polymerase chain reaction in a large number of samples taken from laryngectomy subjects. The PCA muscle was divided into vertical (V) and horizontal (H) portions for analysis. RESULTS AND CONCLUSIONS: No extraocular or IIB myosin gene message is present in PCA or TA, but IIB is expressed in human extraocular muscle. Low but detectable amounts of perinatal and alpha gene message are present in both of the intrinsic laryngeal muscles. In H- and V-PCA, MyHC gene amounts were beta greater than IIA greater than IIX, but amounts of fast myosin RNA were greater in V-PCA. In TA, the order was beta greater than IIX greater than IIA. The profiles of RNA determined here indicate that, in humans, neither PCA nor TA intrinsic laryngeal muscles express unique very fast-contracting MyHCs but instead may rely on differential synthesis and use of beta, IIA, and IIX isoforms to perform their specialized contractile functions.

Margin and local recurrence after sublobar resection of non-small cell lung cancer.

BACKGROUND: Local recurrence is a major concern after sublobar resection (SR) of non-small cell lung cancer (NSCLC). We postulate that a large proportion of local recurrence is related to inadequate resection margins. This report analyzes local recurrence after SR of stage I NSCLC. Stratification based on distance of the tumor (<1 cm vs >or=1 cm) to the staple line was performed. METHODS: We reviewed 81 NSCLC patients (44 female) who underwent operation over an 89-month period (January 1997 to June 2004). Mean forced expiratory volume in one second percentiles (FEV1) was 57%. Mean age was 70 (46-86) years. There were 55 wedge and 26 segmental resections. There were 41 tumors with a margin <1 cm and 40 with a margin >or=1 cm. Local recurrence was defined as recurrence within the ipsilateral lung or pulmonary hilum. RESULTS: There were no perioperative deaths. Mean follow-up was 20 months. Margin distance significantly impacted local recurrence; 6 of 41 patients (14.6%) developed local recurrence in the group with margin less than 1 cm versus 3 of 40 patients (7.5%) in the group with margin equal to or more than 1 cm (P = .04). Of the 41 patients with margins <1 cm, segmentectomy was used in 7 (17%), whereas in the 40 patients with the >or=1 cm margins, segmentectomy was used in 19 (47.5%). CONCLUSIONS: Margin is an important consideration after SR of NSCLC. Wedge resection is frequently associated with margins less than 1 cm and a high risk for locoregional recurrence. Segmentectomy appears to be a better choice of SR when this is chosen as therapy.

Dental health status of liver transplant candidates.

A prerequisite dental evaluation is usually recommended for potential organ transplant candidates. This is based on the premise that untreated dental disease may pose a risk for infection and sepsis, although there is no evidence that this has occurred in organ transplant candidates or recipients. The purpose of this study was to assess the prevalence of dental disease and oral health behaviors in a sample of liver transplant candidates (LTCs). Oral examinations were conducted on 300 LTCs for the presence of gingivitis, dental plaque, dental caries, periodontal disease, edentulism, and xerostomia. The prevalence of these conditions was compared with oral health data from national health surveys and examined for possible associations with most recent dental visit, smoking, and type of liver disease. Significant risk factors for plaque-related gingivitis included intervals of more than 1 yr since the last dental visit (P = 0.004), smoking (P = 0.03), and diuretic therapy (P = 0.005). Dental caries and periodontal disease were also significantly associated with intervals of more than 1 yr since the last dental visit (P = 0.004). LTCs with viral hepatitis or alcoholic cirrhosis had the highest smoking rate (78.8%). Higher rates of edentulism occurred among older LTCs who were less likely to have had a recent dental evaluation (mean 88 months). In conclusion, intervals of more than 1 yr since the last dental visit, smoking, and diuretic therapy appear to be the most significant determinants of dental disease and the need for a pretransplantation dental screening evaluation in LTCs. Edentulous patients should have periodic examinations for oral cancer.

General dentists' evaluation of anesthesia sedation education in U.S. dental schools.

To assess the quality and quantity of sedation education in U.S. dental schools, a prospective, questionnaire-based survey was administered to general dental practitioners who graduated in 2003. Questionnaires were sent via facsimile to recent dental graduates using a list obtained through the American Dental Association. The response rate was 54 percent; 718 of the 1,328 nine-question surveys were returned. The response to the questionnaires indicates a perceived need for sedation care by the majority of recent graduates and low overall satisfaction with the quality of sedation education in U.S. dental schools. The general consensus of most 2003 dental school graduates is that they have gained little or no hands-on experience in sedation techniques and would have supported an increase in tuition and fees if an institution were to offer more efficient sedation training. With increased popularity and high patient demand for sedation techniques, the new dentist feels a need for sedation education before graduation.

Efficacy of laparoscopic fundoplication in controlling pulmonary symptoms associated with gastroesophageal reflux disease.

BACKGROUND: Gastroesophageal reflux disease (GERD)-induced pulmonary symptoms (PS) can be difficult to control. The effectiveness of laparoscopic fundoplication (LF) in controlling PS among patients with medically recalcitrant GERD is poorly documented. We evaluated our results in controlling important PS in patients with GERD undergoing LF. METHODS: Seventy-four patients (28 men, 46 women) were identified with clinically important PS from a prospective cohort of 155 patients undergoing elective LF for recalcitrant GERD. Median age was 52.5 years (range, 29-84 years). Sixty-seven (91%) patients were taking proton pump inhibitors at the time of operation. Quality of life by using the SF36 physical (PCS) and mental (MCS) component summary scores (normal, 50) and heartburn severity by using the health-related quality of life (HRQOL) (best score, 0; worst score, 45) were measured. RESULTS: All 74 patients with PS survived operation, and minor morbidity occurred in 5 (7%) patients. Median hospital stay was 2 days (range, 1-6 days), and return to normal activity was seen at 2.2 weeks (range, 1-8 weeks). Median follow-up was 12 months. PS were improved significantly (P < .01) for hoarseness (62% to 17.6%), bronchospasm (60% to 9.5%), and aspiration (22% to 1.4%). Before LF, 11 (14.9%) patients required bronchodilators or oral steroids. Postoperatively such therapy was required in only 3 (4.2%) patients (P = .019), with no patient requiring oral steroids. Patients with poorer control of their GERD on the basis of high HRQOL scores had significantly more PS after operation. CONCLUSIONS: A significant number of patients with medically recalcitrant GERD (46% from our prospective database) have important PS. LF can improve PS, decrease requirement for pulmonary medications, as well as improve typical reflux symptoms and quality of life.

Lobar and sublobar resection with and without brachytherapy for small stage IA non-small cell lung cancer.

OBJECTIVE: Computed tomographic screening is detecting ever smaller peripheral non-small cell lung cancers. These smaller cancers are amenable to sublobar resection, but sublobar resection is not currently the treatment of choice. This study compared sublobar resection with lobar resection for stage IA non-small cell lung cancers to assess whether sublobar resection is appropriate treatment for certain lesions. The use of adjuvant brachytherapy was also evaluated. METHODS: A retrospective multicenter study of 291 patients with T1 N0 disease was done. Outcomes after sublobar resection (n = 124) were compared with those after lobar resection (n = 167). Brachytherapy was used in conjunction with 60 (48%) sublobar resection operations. Analysis based on tumor diameter was performed. RESULTS: There were 137 cancers smaller than 2 cm and 154 cancers ranging from 2 to 3 cm. Patients undergoing sublobar resection were older (68.4 vs 66.1 years, P = .018) with poorer pulmonary function (forced expiratory volume in 1 second of 53.1% vs 78.2%, P = .001). Mean follow-up was 34.5 months. Brachytherapy decreased local recurrence rate significantly among patients undergoing sublobar resection, from 11 (17.2%) to 2 (3.3%). For tumors smaller than 2 cm, there was no difference in survival between sublobar resection and lobar resection groups. For the larger tumors (2-3 cm), median survival was significantly better in the lobar resection group, at 70 versus 44.7 months ( P = .003). CONCLUSION: Intraoperative brachytherapy may reduce the local recurrence that is usually reported with sublobar resection. Our experience supports the further investigation of the use of sublobar resection with brachytherapy for peripheral stage IA non-small cell lung cancers smaller than 2 cm.

Frictional resistances of different bracket-wire combinations.

BACKGROUND: It has been suggested that the frictional resistance of ceramic brackets can be reduced by either lining the slots with stainless steel or by contouring the base of the slot. OBJECTIVES: The objectives of this investigation were to compare in vitro the static and kinetic frictional resistances of ceramic brackets with metal lined slots ("Clarity", CL), stainless steel brackets ("Miniature Twin", MT), and two ceramic brackets with different slot designs ("Contour", CO; "Transcend", TR). METHOD: Two sizes (0.018 x 0.025 inch; 0.021 x 0.025 inch) of stainless steel (SS), nickel titanium (NiTi) and beta titanium (beta-Ti) wires were drawn through the brackets. All brackets had 0.022 inch slots, and the brackets and wires were used once. The brackets were of different widths: CL, 0.180 inch; CO, 0.114 inch; MT, 0.118 inch; TR, 0.138 inch. An Instron Universal Testing Machine was used in this study. RESULTS: There were no significant static or kinetic frictional differences when the smaller 0.018 x 0.025 inch wires were drawn through the brackets. There were no statistically significant static or kinetic frictional differences between the CL-CO, CL-MT and CO-MT bracket pairs when the 0.021 x 0.025 inch wires (SS, NiTi, beta-Ti) were used. There were no significant kinetic frictional resistance differences between the CL-TR and MT-TR when the SS wires were used. In general the static and kinetic resistances of the 0.021 x 0.025 inch wires of NiTi wire < SS wire < beta-Ti wire. Regardless of wire type some of the lowest kinetic resistances were found with the narrow CO brackets with the rounded slot bases. The highest static and kinetic frictional resistances were found with the wide TR bracket, and with stainless steel and beta-Ti wires. CONCLUSION: The high static and kinetic frictional resistances of ceramic brackets can be reduced either by lining the slots with stainless steel or by reducing the bracket width and rounding the slot base.

Students' perceived importance of diversity exposure and training in dental education.

Intercultural competence is an important component of the doctor-patient relationship in the multicultural climate evolving in the United States. We hypothesized that 1) exposure to racial and ethnic diversity in the student body, faculty, staff, and patient population in dental school and 2) a dental school curriculum that includes presentations on issues concerning racial and ethnic diversity will contribute to students' feeling more competent and confident to enter the multicultural work environment that is rapidly developing in the United States. A Likert-type scale questionnaire was administered to 627 fourth-year dental students enrolled in seven dental schools representing geographically diverse regions of the United States. Of these, 376 questionnaires were returned for a response rate of 60 percent. Results indicated that both the perception of diversity in the school environment and the presentation of diversity-specific content in the curriculum had moderately positive and significant correlations with the students' perception of their competency or ability to serve and work with diverse populations. The respective Pearson correlation coefficients for diversity in the school environment and diversity curriculum were .497 (p<.001) and .459 (p<.001). These results support the hypotheses that diversity exposure and training in the dental school environment are important for dental students entering a multicultural workplace.