Objective. This study aims to compare several mechanical and optical properties between three different CAD/CAM materials. The properties tested are: flexural strength, modulus of elasticity, hardness, translucency and surface gloss. Background. Typically, CAD/CAM restorations are either ceramic based or resin based. A new resin-ceramic hybrid material has recently been introduced and is thought to combine the advantages of both materials. Methods. Samples were divided into three groups, leucite-reinforced porcelain (IPS Empress CAD), lithium dicilicate (IPS e.max CAD) and resin-ceramic hybrid material (Vita Enamic). Twenty-six bar-shaped specimens were fabricated for each group by cutting standard CAD/CAM blocks. 3-point bending test and Vickers diamond pyramid indenters were used to test the flexural strength and microhardness respectively. Seven veneers were fabricated for each material with a thickness of 0.5 mm using a CAD/CAM milling machine. These veneers were used to test the optical properties via spectrophotometry and gloss-meter analysis. One-way ANOVA, and the Tukey HSD post hoc test were used for statistical analysis between the groups (P

The purpose of this study was to evaluate the effects of sodium hypochlorite on the organic and inorganic composition of enamel. Background: With the advent of enamel bonding for orthodontic appliances in the late 1970s, it has been shown that traditional phosphoric acid etching affects the inorganic portion of the enamel.1, 2 In an attempt to enhance the acid etching pattern and, furthermore, the bond strength, additional pretreatment techniques that target the organic components of the enamel biofilm have been proposed. One such method is the non-invasive enamel pretreatment with 5.25% sodium hypochlorite (NaOCl) prior to phosphoric acid etching.3, 4 It has been suggested that the mechanism by which sodium hypochlorite enhances the etching pattern is enamel deproteinization, in which organic elements, including the acquired film, are removed from the enamel surface.3, 5 This presumption is based on the multitude of endodontic literature supporting the use of NaOCl as an effective irrigant in root canal therapy6-13. In contrast to dentin and pulpal tissue, enamel is comprised of minimal organic matter.14, 15 As a result of this fact and the limited amount of experimentation of the effect of NaOCl on the enamel surface, the true mechanism by which sodium hypochlorite enhances the etching pattern of enamel is questionable.5, 16 The objective of this study was to determine the compositional effects of sodium hypochlorite on human enamel. Methods: Following IRB approval, 120 enamel sections from 22 extracted human premolar teeth were randomly divided into three experimental groups and one control group.17 The control group (E = enamel) received no treatment. The first experimental group (A = phosphoric acid) received a 15-second treatment with 37% phosphoric acid, rinsed with distilled water and air sprayed for 20 seconds, then dried with oil free compressed air. The second experimental group (H = sodium hypochlorite) received a treatment of 5.25% sodium hypochlorite for 60 seconds, washed with distilled water for 10 seconds, and dried. The third experimental group (HA = sodium hypochlorite + phosphoric acid) received a treatment of 5.25% sodium hypochlorite for 60 seconds, washed with distilled water for 10 seconds, dried, then receive the 15-second treatment with 37% phosphoric acid as in Group A.3 Following treatment preparations of the four groups, scanning electron microscopy (SEM)/energy-dispersive X-ray spectrometer (EDX) analysis was performed for all groups.18 For elemental concentration, a one-way ANOVA and Tukey’s post hoc statistical tests were applied.17, 19, 20 ANOVA and Tukey tests were performed at a significance level of p ≤ 0.05. Results: There were no significant effects of treatment on the enamel elements carbon (C), calcium (Ca) sodium (Na), oxygen (O), and phosphorous (P). There was a significant effect of treatment on the amount of chlorine (Cl) in enamel between groups acid (A) and hypochlorite + acid (HA) as well as between groups hypochlorite (H) and hypochlorite + acid (HA) (p = 0.004). The amount of variation of iodine (I) in the enamel composition between untreated enamel (E) and enamel treated with sodium hypochlorite + phosphoric acid (HA) was significant (p = 0.004). Additionally, there was a significant decrease in the quantity of antimony (Sb) found in the control group (E) versus the hypochlorite + acid (HA) experimental group (p = 0.002). Lastly, tin (Sn) was significantly reduced from the enamel surface (E) when treated with hypochlorite + acid (HA) (p = 0.008). Conclusions: The various treatments minimally affected the elemental concentrations of C, Ca, Na, O, and P. The amount of chlorine present in enamel significantly increased following treatment with sodium hypochlorite (H) alone and even more so following treatment with phosphoric acid and sodium hypochlorite (AH). In contrast, elements I, Sb, and Sn demonstrated a congruent reduction in concentration after treatment with hypochlorite and acid (HA). Although it has been hypothesized that sodium hypochlorite targets the organic pellicle present on the surface of enamel via a process known as deproteinization, the findings presented here suggest that pre-treatment with NaOCl impacts the inorganic components of enamel more so than the organic constituents. These quantitative findings corroborate the enhanced etching pattern that can be visualized under scanning electron microscopy in this as well as previous studies.

Objective: This study was conducted to determine how oral health-related quality of life (OHQoL) changes during the late stage of comprehensive fixed orthodontic treatment in adolescents and what factors may be involved. Background: Completion of orthodontic treatment has been shown to improve patients’ OHQoL due to the changes in esthetics, function and emotional well-being. The levels of OHQoL fluctuate throughout treatment where an initial decrease within the first 6 months occurs followed by an improvement towards patients’ pre-treatment levels. At 18 months of fixed orthodontic treatment, the level is unclear. The aims of this study were to clarify the changes of OHQoL during this late stage of fixed orthodontic treatment beyond 18 months in adolescents and to identify factors, including dental extractions, patient compliance, use of adjunctive appliances, and patient demographics, which may contribute to the OHQoL. Methods: This case-control study consisted of 154 adolescent patients undergoing comprehensive fixed orthodontic treatment from the Nova Southeastern University orthodontic department. Subjects were selected based upon the number of months in comprehensive fixed orthodontic treatment. Completion of the Oral Health Impact Profile short form (OHIP-14) as well as occurrence of dental extraction during orthodontic treatment, use of adjunctive appliances, frequency of emergency and failed appointments, level of oral hygiene, and subjects’ age and gender were all recorded. Statistical analysis using structural equation modeling was used to determine the direct and indirect effects to subjects’ OHQoL. Results: The model accounted for 35% of the variance in OHQoL. There were no significant differences in average OHIP-14 scores between the initial stage of 5-7 months and final stage of 18 months and over in orthodontic treatment. The analysis of direct factors showed that females and subjects with adjunctive appliances possessed higher OHIP-14 scores. Conclusions: Treatment time beyond 18 months of treatment was not a significant factor affecting adolescents’ OHQoL. Female patients and those with adjunctive appliances expressed poorer levels of OHQoL. These factors may be attributed to the scores within the physical and psychological domains as these patients experienced pain and discomfort from appliance wear as well as negative impact on their self-esteem during comprehensive fixed orthodontics.

Objectives: To evaluate and compare the color of porcelain veneers with try-in paste in relation to porcelain veneers with permanent cement. Also, to evaluate and compare combinations of three different shades and thicknesses of porcelain veneers and three cement shades before and after final cementation. Additionally, to evaluate and compare the color of porcelain veneers with cured permanent cement before and after aging. Background: Porcelain veneers and ceramic restorations have become one of the most popular approaches in the anterior area due to their natural appearance and esthetics. However, more conservative approaches have led to thinner restorations with increased translucency. A potential drawback to these restorations is that any color change in the luting cement can become clinically visible, and possibly affect esthetic appearance. Methods: One hundred and eight specimens were cut from feldspathic porcelain blocs (Vitablocs Mark II for CEREC). Three different Vita 3D- Master 1M1, 2M2, and 3M1 shades were assessed. All specimens were 12 x 14 mm, with three different thicknesses of 0.3, 0.5, and 1.0 mm. Light-cured resin cement (Variolink Veneer, Ivoclar Vivadent) with three different shades was used. The specimen color alone, with the try-in paste, and with pre-cured and post-cured resin cement was measured using a spectrophotometer (Color Eye 7000A), which measures CIE-L*a*b* values. Specimens were subjected to 30,000 cycles of accelerated aging (Themo-cycling, Sarbi Dental Enterprises Inc.). Color measurement for all specimens was performed again and ∆E values between groups been calculated. Statistical analysis was performed using one-way and three-way ANOVA, with level of significant set at α=0.05, to assess differences between groups. This was followed by post hoc Tukey's tests. Results: Statistical analysis showed a significant difference between try-in paste and corresponding cured resin cement. Pre-cured and post-cured resin cement values showed a significant difference between cement shades. Moreover, statistically significant differences were found between post-cured cement and after 30,000 cycles of thermo-cycling. Conclusions: The final color of porcelain veneers was highly affected by the different shades of resin cement and by the thicknesses of the porcelain veneer. The use of higher ceramic thickness decreased the ∆E values when compared to thinner veneers. Also, color stability of ceramic veneer restorations luted with resin cement, was significantly influenced by the aging.

Introduction: The palate is a well-established donor site for obtaining graft tissue in periodontal plastic surgery procedures. However, proximity to the adjacent teeth on the lateral aspect and the greater palatine neurovascular bundle (GPB) on the medial aspect limit the amount of graft tissue that can be obtained from the palate. Previous studies have been concerned with the location of the greater palatine foramen as well as the greater palatine artery (GPA) and have established guidelines on how to estimate the distance between the teeth and the GPB. Traditionally, clinicians follow these guidelines and choose to avoid removing graft tissue in the area close to the GPB out of fear of possible complications such as hemorrhaging and paresthesias. Objectives: The purpose of the present investigation is to locate the position of the greater palatal artery (GPA) in relation to surrounding anatomical landmarks and determine if the tissue thickness covering the GPA is sufficient to permit gingival grafts to be obtained in the area close to the GPB. Materials and methods: Cadaver dissections were performed on a total of ten (n=10) cadaver hemifaces of which 7 were partially and 3 were completely edentulous. From the greater palatine foramen to the incisive foramen, the palatal tissues of the cadavers were dissected into vertical slices of 3 mm in width perpendicular to the median palatine raphe using a double bladed scalpel. On each tissue slice, the distance from the epithelial surface to the superior border of the vessel, the diameter of the vessel, the distance from the inferiorborder of the vessel to the palatal bone, the distance from median palatine raphe to the GPA and the distance from teeth or midline of the alveolar crest to the GPA were measured using both a periodontal probe and a digital caliper. The measurements were correlated to each other, the angle of the palatal vault, an estimate of the palatal depth and the head length of the cadavers. Results: The mean thickness of the tissue above the GPA was 4.30 ± 1.61 mm with a range of 1.92 – 8.72 mm. The tissue thickness decreased consistently from the 3rd molar to the canine area with the thickest mean tissue being in the 2nd molar region with 6.25 ± 1.09 mm and shallowest mean tissue thickness in the region of the lateral incisor with 2.92 ± 0.46 mm. The mean distance of the GPA from the median palatine raphe is 10.34 ± 3.41mm ranging from 13.77 ± 1.67 mm to 6.02 ± 0.83 mm with the greatest distance being from the 3rd molar region and smallest distance being from the lateral incisor area. No statistically significant correlations were found between the angel of the palatal vault, the estimate of the palatal depth and the head length. A significant correlation (R2=0.92) was found between the total palatal tissue thickness and tissue thickness above the GPA. Discussion: There was adequate gingival tissue above the GPA to harvest tissue for free gingival grafts of 1 - 1.5 mm in thickness in the entire palate. Donor tissue for 1.5 mm thick connective tissue grafts with a 1.5 mm epithelial flap could be obtained opposing the 1st molar and posterior to it staying above the GPA. Donor site for palatal grafts can be extended in a medial and posterior direction.A Formula (Tissue Thickness above the GPA = (Total Thickness of palatal tissue - 0.967) x 0.9) has been derived, which accurately locates the GPA based on the thickness of the palatal tissue. Unique to this study were measurements from the median palatine raphe, which will provide the clinician with a new landmark to more reliably locate the GPA at various locations on the palate. Conclusion: This descriptive pilot study on human cadavers provides a formula to locate the GPA within the palate using the total palatal tissue thickness and suggests that graft tissue can be harvested from the tissue above the GPA in the entire palate for FGGs and opposing to the 1st molar and posterior to it for CTGs not exceeding 3 mm in depth.

Background: The World Health Organization estimates that there are 517 million people in the world who are visually impaired due to uncorrected presbyopia. Equal sphere ready-made bifocal and single vision reading spectacles are an inexpensive alternative to custom made spectacles. Methods: A visual satisfaction questionnaire was administered before patients were examined at an outreach clinic and again after ready-made bifocals or reading spectacles were dispensed. The results of both sets of questions along with presenting acuities, corrected acuities, refractive data, and willingness to pay were analyzed. Results: There was an unmet need of 38% (of the 338 subjects that needed glasses only 208 had them). There was no gender bias; the unmet need was higher in the rural areas (47% rural, 36% urban). Those who could not read were 3.4 times less likely to have the glasses they needed than the literate. Unmet need decreased with every level of education. Those without any schooling showed 77% prevalence of unmet need and those with university education had an unmet need rate of 32%. Ready-made spectacles were dispensed to 89.5% of those examined. The ready-made bifocals were very well accepted, with the percentage of subjects giving the highest satisfaction rating improving from a presenting value of 11% to 89.4% with the bifocals at distance and from 6.6% to 89.4% at near. Distance visual acuity of 20/40 or better improved from the presenting value of 60% to 84.5% and near vision of 20/40 or better improved from the presenting value of 44% to 97%. With ready-made single vision readers, functionally good near vision (20/40 or better) improved from a presenting value of 38% to 97%. The highest ranking for near satisfaction improved from 6.3% to 86.6%. The subjects indicted that they would be willing to pay US$18.39 to replace the bifocals and US$16.67 to replace the readers. Conclusion: There is a high unmet need for vision correction in the population over age 35 in Nicaragua. Dissatisfaction with distance and near vision is very high. Although custom made glasses are ideal, ready-made bifocals and ready-made single vision readers are an acceptable and affordable alternative.

Purpose: It is unknown whether individuals with two balanced eyes show quicker response and lower threshold in fine stereoscopic detection. Previous methods to measure ocular dominance were primarily qualitative, which do not quantify the degree of dominance and show limitation in identifying the dominant eye. In this study, we aimed at quantifying the difference of ocular strength between the two eyes with ocular dominance index (ODI) and studying the association of ocular balance between the two eyes with stereoscopic detection. Methods: Stereoscopic threshold was measured in thirty-three subjects. Stereopsis was measured with random dot stimuli. The minimal detectable disparity (Dmin) and the minimal time needed to acquire the best stereoacuity (Tmin) were quantified. Ocular dominance was measured by a continuous flashing technique with the tested eye viewing a titled Gabor patch increasing in contrast and the fellow non-tested eye viewing a Mondrian noise decreasing in contrast. The log ratio of Mondrian to Gabor’s contrasts was recorded when a subject just detected the tilting direction of the Gabor during each trial. The t-value derived from a t-test of the 50 values obtained in each eye was used to determine a subject’s ODI (ocular dominance index) to quantify the degree of ocular dominance. A subject with ODI ≥ 2 (p < 0.05) was defined to have clear dominance and the eye with larger mean ratio was the dominant eye. Results: The Dmin (55.40 arcsec) in subjects with two balanced eyes were not significantly different from the Dmin (43.29 arcsec) in subjects with clear ocular dominance (p = 0.87). Subjects with two balanced eyes had significantly (p = 0.01) shorter reaction times on average (Tmin = 138.28 msec) compared to subjects with clear dominance (Tmin = 1229.02 msec). Tmin values were highly correlated with ocular dominance (p = 0.0004). Conclusion: Subjects with two relatively balanced eyes take shorter reaction time to achieve optimal level of stereoacuity. Keywords: Ocular Dominance, Local Stereopsis, Binocular, Balanced Eyes, Anisometropia

Background. The United States military relies on visual acuity standards to assess enlistment induction and military occupational specialty eligibility. In addition, the military recently instituted the Vision Readiness and Classification System to monitor Soldiers' combat vision readiness. The primary aim of this study was to investigate the relationship between visual acuity and marksmanship performance using a single blind randomized trial with the Engagement Skills Trainer 2000. Methods. Marksmanship performance was evaluated in 28 subjects under simulated day and night conditions with habitual spectacle prescription and contact lenses that created visual blur. Results. The relationship between visual acuity and marksmanship performance was found to have a statistically significant correlation of -0.735 with a 95% confidence interval from -0.790 to -0.669. Subsequently, 54 percent of the variance in marksmanship performance was accounted for by visual acuity. In addition, a panel poison regression model using an independent correlation structure revealed significant differences (p< .001) as visual acuity decreased from 20/25 to 20/50. Conclusions. Marksmanship performance decreases as visual acuity decreases. This relationship supports the use of a visual acuity requirement in the assessment of military readiness.

Purpose: The profession of physical therapy uses physical therapist clinical instructors to educate students in the clinical education portion of the curriculum. The requirements to become a clinical instructor are minimal and non- specific regarding formal training and development. A variety of educational opportunities is available to clinical instructors, but the evidence in the physical therapy literature is conflicting regarding the effectiveness of these programs. Additionally, no previous research regarding the meaning of competence, nor the pathway to achieving competence as a clinical instructor was found. Therefore, the purpose of this study was to describe the experience of achieving competence as perceived by clinical instructors who have chosen different paths toward becoming effective CIs. Methods: This study utilized phenomenological methodology to explore the meaning of clinical instructor competence and the experience of achieving competence from the perspectives of the clinical instructors themselves. Data was collected through the use of focus groups, semi-structured interviews and written statements. Data was analyzed for themes using thematic analysis. Participants: A purposive sample of twenty-nine physical therapist clinical instructors was recruited to participate in five focus groups, each group consisted of 5-7 participants. Results: An overarching theme of “Empowerment” emerged from the data analysis of the transcriptions and field notes. This overarching theme was supported by eight themes which resonated across the five focus groups. These themes were 1: The meaning of competence, 2: “My first student”, 3: Finding the way, 4: Feeling supported, 5: A fork in the road, 6: Barriers to achieving competence, 7: The “ah-ha” moment, 8: “Ongoing road”. Conclusion: The results of this study provide a description and interpretation of the meaning of clinical instructor competence and the journey of achieving competence. These findings can inform and empower clinical instructors on their own journey to competence. CCCEs may also find a deeper awareness of the meaning of competence and the importance of providing support for CIs. The physical therapy education community and it’s professional bodies can also be informed by these findings in establishing a definition of clinical instructor competence. As well as give direction to future efforts and programs designed to prepare clinicians to effectively educate students in the clinic setting.

Purpose: This study will identify that patients with chronic neck pain have an altered autonomic functioning compared to a control group, and that manipulation might directly influence the autonomic nervous system as measured by using a fully automated pupillometry system. Subjects: 100 chronic pain patients and 50 control subjects participated in this study to achieve a power of 0.80, effect size of 0.5, and a type I error rate of 0.05 for two-tailed hypothesis testing. Method: A quasi-experimental design was be used. The ANOVA and Chi square test were used to establish homogeneity of baseline characteristics. The Mann-Whitney U test was performed to compare the pre-intervention pupil diameter amongst the groups. The Friedman's test was used to determine the pupil diameter change during the three measurements. The Wilcoxen Signed-ranks test was used to analyze the difference in pupil size between the pre- and post-intervention measures and to determine if there was a difference in pupil diameter between the two groups undergoing the thoracic manipulation. The Kruskal-Wallis test was used to compare the pupil diameter change to the presence of joint sounds. And the Fisher's Exact test was used to determine the relationship between the number of pops and the VAS change score > 13mm. Results: This study demonstrated that the chronic pain group had a statistically significant smaller pupil diameter than the healthy control group (P=0.022). Manipulation resulted in a relative increase in pupil diameter following the manipulation, however this was not statistical significant. There was a statistical significant decrease in pupil diameter in the placebo group (pConclusions: It appears that a T3-T4 manipulation results in a relative non-specific increase in sympathetic activity. Recommendations: Manipulation may be used by physical therapists to affect the autonomic nervous system. Visual pupil assessment may become part of the evaluation process to identify patients that might present with autonomic dysfunction and to determine the effect of treatment modalities.