Fracture Resistance of Additively Manufactured Zirconia Crowns when Cemented to Implant Supported Zirconia Abutments: An in vitro Study.

PURPOSE: To compare the fracture resistance of implant-supported milled zirconia, milled lithium disilicate, and additively manufactured zirconia crowns. MATERIALS AND METHODS: Maxillary cast with a dental implant replacing right second bicuspid was obtained. Custom abutments and full-contour crowns for milled zirconia, milled lithium disilicate, and additively manufactured zirconia crowns (n = 10/group) were digitally designed and fabricated. The crowns were cemented to implant-supported zirconia abutments and mounted onto polyurethane blocks. Fracture resistance was determined by vertical force application using a universal testing machine at a crosshead speed of 2 mm/minute. Kruskal-Wallis test was used to analyze data and failure mode was determined for all the groups. RESULTS: Milled zirconia crowns demonstrated the highest median fracture resistance (1292 ± 189 N), followed by milled lithium disilicate (1289 ± 142 N) and additively manufactured zirconia (1243.5 ± 265.5 N) crowns. Statistical analysis showed no significant differences in fracture resistance between the groups (p = 0.4). All specimens fractured at the implant-abutment interface. CONCLUSION: Additively manufactured zirconia crowns demonstrated similar fracture resistance to milled ceramic crowns, when cemented to implant supported zirconia abutments. The results of this in vitro study signify the promising potential of additive manufacturing for the fabrication of all ceramic zirconia crowns.

Twenty-year follow-up study on a patient-fitted temporomandibular joint prosthesis: the Techmedica/TMJ Concepts device.

PURPOSE: To evaluate subjective and objective outcomes of patients receiving Techmedica (currently TMJ Concepts) patient-fitted temporomandibular joint (TMJ) total joint replacement (TJR) devices after 19 to 24 years of service. PATIENTS AND METHODS: This prospective cohort study evaluated 111 patients operated on by 2 surgeons using Techmedica (Camarillo, CA) patient-fitted TMJ TJR devices from November 1989 to July 1993. Patients were evaluated before surgery and at least 19 years after surgery. Subjective evaluations used standard forms and questions with a Likert scale for 1) TMJ pain (0, no pain; 10, worst pain imaginable), 2) jaw function (0, normal function; 10, no movement), 3) diet (0, no restriction; 10, liquid only), and 4) quality of life (QoL; improved, the same, or worse). Objective assessment measured maximum incisal opening (MIO). Comparison analysis of presurgical and longest follow-up data used nonparametric Mann-Whitney and Wilcoxon signed rank tests. Spearman correlations evaluated the number of prior surgeries in relation to objective and subjective variables. RESULTS: Of the 111 patients, 56 (50.5%) could be contacted and had adequate records for inclusion in the study. Median follow-up was 21 years (interquartile range [IQR], 20 to 22 yr). Mean age at surgery was 38.6 years (standard deviation, 10 yr). Median number of previous TMJ surgeries was 3 (IQR, 4). Presurgical and longest follow-up data comparison showed statistically significant improvement (P < .001) for MIO, TMJ pain, jaw function, and diet. At longest follow-up, 48 patients reported improved QoL, 6 patients reported the same QoL, and 2 patients reported worse QoL. Spearman correlations showed that an increased number of previous surgeries resulted in lower levels of improvement for TMJ pain and MIO. CONCLUSIONS: At a median of 21 years after surgery, the Techmedica/TMJ Concepts TJR continued to function well. More previous TMJ surgeries indicated a lesser degree of improvement. No devices were removed owing to material wear.

Short-term skeletal and dentoalveolar effects of overexpansion.

OBJECTIVES: To evaluate whether the amount of rapid maxillary expansion differentially affects the skeletal and dentoalveolar changes that occur. MATERIALS AND METHODS: This randomized controlled trial included 23 patients who had rapid maxillary expansion (RME). Subjects were randomly assigned to a conventional expansion control group (n = 12) or an overexpansion group (n = 11), who started treatment at 13.2 ± 1.5 and 13.8 ± 1 years of age, respectively. Cone beam computed tomography scans (11 cm) were obtained prior to rapid maxillary expander (RME) delivery and approximately 3.7 months later. Initial hand-wrist radiographs were used to determine the participants' skeletal maturity. RESULTS: The RME screws were activated 5.6 ± 1.2 mm and 10.1 ± 0.6 mm in the conventional and overexpansion groups, respectively. Overexpansion produced significantly greater expansion of the nasal cavity (2.1X-2.5X), maxillary base (2.3X), buccal alveolar crest (1.4X), and greater palatine foramina (1.9X). Significantly greater intermolar width increases (1.8X) and molar inclination (2.8X) changes were also produced. The nasal cavity and maxillary base expanded 23%-32% as much as the screws were activated. Skeletal expansion was positively correlated with RME screw activation (R = 0.61 to 0.70) and negatively correlated (R = -0.56 to -0.64) with the patients' skeletal maturation indicators (SMIs). Together, screw activation and the patients' SMI scores explained 48%-66% of the variation in skeletal expansion. CONCLUSIONS: This pilot study shows that overexpansion produces greater changes than conventional expansion, with greater skeletal effects among less mature patients.

The evidence-based dentistry initiative at Baylor College of Dentistry.

This report describes the impact of an R25 Oral Health Research Education Grant awarded to the Texas A&M Health Science Center-Baylor College of Dentistry (BCD) to promote the application of basic and clinical research findings to clinical training and encourage students to pursue careers in oral health research. At Baylor, the R25 grant supports a multi-pronged initiative that employs clinical research as a vehicle for acquainting both students and faculty with the tools of evidence-based dentistry (EBD). New coursework and experiences in all 4 years of the curriculum plus a variety of faculty development offerings are being used to achieve this goal. Progress on these fronts is reflected in a nascent "EBD culture" characterized by increasing participation and buy-in by students and faculty. The production of a new generation of dental graduates equipped with the EBD skill set as well as a growing nucleus of faculty who can model the importance of evidence-based practice is of paramount importance for the future of dentistry.

Characterization of the maxillary complex in unilateral cleft lip and palate using cone-beam computed tomography: a preliminary study.

Deficiencies in maxillary growth have often been implicated in suboptimal results of cleft lip and palate therapy. Cone-beam computed tomography provides an opportunity to look at the dimensions of the maxillary complex in three dimensions in a way that is not possible with lateral cephalograms or dental models. The purposes of this preliminary study were to outline a new set of 18 cone-beam computed tomographic measurements, apply them to 6 patients with unilateral cleft lip and palate (UCLP), and contrast them to a comparable sample of 7 normal young adults. The patients with UCLP were treated with a single protocol by a single surgeon and orthodontist. The 18 measurements had a mean intrarater reliability of 0.95 and ranged from 0.40 to 2.23 for the individual measurements. The mean interrater reliability was 1.01 and ranged from 0.40 to 2.45 for the individual measurements. Significant differences between the patients with UCLP and control subjects (combined sex samples) were found in palate length, anterior palate thickness, overall sagittal maxillary length, and premaxillary height (Mann-Whitney U tests, P

Creating a Supportive Educational Research Culture at a Dental School by Identifying Obstacles and Solutions.

The aim of this study was to identify the extent of educational research conducted at one U.S. dental school and to assess faculty needs for engaging in it more fully. A task force developed and administered a survey to all the school's full-time faculty members in January 2014. The response rate was 73.6% (n=106/144). The majority of the respondents were clinicians (73%), had a primary responsibility for teaching (80%), and were non-tenure track (62%). Thirty-six percent (n=24) of the non-tenure-track respondents reported being expected to engage in scholarship as well as the 38% (n=40) who were on the tenure track, for a total of 60% (n=64/106). Overall, 51% of respondents reported they had a half-day or less for scholarship. Clinical faculty respondents had significantly less time for scholarship than non-clinical (p<0.001). Two-thirds (n=72, 68%) said they had not received research training, and over half (n=56, 53%) had never conducted educational research. The most common answers for why respondents did not conduct educational research were "do not know how" (n=32%) and "not required" (n=23%). Help with statistical analysis was reported as the most important support factor, followed by having collaborators, help with research design, time, funding, and travel. While overall interest in conducting educational research was moderate (median=5 on a 1-10 scale, IQR=3,8), a highly interested group (n=45) had produced more research than others (p≤0.041). This group desired more small grants (91%) and training opportunities (89%, p≤0.001). In response to one of the findings of this study, a small-grant program of $15,000 annually for educational research was implemented in May 2014. Funded by this program, 11 projects have been initiated with both scholarship and learning improvement outcomes.

Does the Texas First Dental Home Program Improve Parental Oral Care Knowledge and Practices?

PURPOSE: This study evaluated the effectiveness of the Texas Medicaid First Dental Home (FDH) by comparing the oral health knowledge, practices, and opinions of participating vs. non-participating parents. METHODS: A 29-question survey (English & Spanish) was developed and administered to 165 parents of children under three years old (FDH=49, Non-FDH=116) who visited qualifying Medicaid clinics in Texas. RESULTS: Mann Whitney U tests showed that FDH parents scored higher on overall knowledge (P=0.001) and practice scores (P<0.001). FDH parents responded correctly more often than non-FDH about the recommended amount of toothpaste for toddlers (P<0.001). More FDH parents knew tap water was a potential source of fluoride (P<0.001). The FDH parents scored marginally higher about when a child should have the first dental visit (P=0.051). More Non-FDH parents let their child go to sleep with a bottle, sippy cup or pacifier (P<0.001). CONCLUSIONS: FDH visits are having a positive impact on Texas parents by increasing their oral healthcare knowledge and practices. This is the first step towards improving the oral health of children.

Prevalence of Periapical Rarefying Osteitis in Patients with Rheumatoid Arthritis.

INTRODUCTION: The effect of rheumatoid arthritis (RA) on the healing and pathophyisiology of apical periodontitis is unknown because there is no study in the literature evaluating the association of RA with the prevalence of periapical rarefying osteitis (PAR) and endodontic treatment. Therefore, the goal of this cross-sectional study was to evaluate the prevalence of PAR and root canal treatment in RA patients when compared with controlled individuals. METHODS: Full-mouth radiographs of 131 individuals with RA were examined and compared with 131 controls that were sex and age matched exactly with the diseased group. The total number of teeth, presence or absence of root canal filling, quality of root canal filling, quality of restoration, and periapical status were recorded. RESULTS: Overall, the prevalence of teeth with PAR was 4.0% in the diseased group and 3.5% in the control group (P > .05). The prevalence of root canal-treated teeth was 6.2% in the RA group and 5.6% in the control group (P > .05). Controls have significantly more teeth than those with RA (P = .027). CONCLUSIONS: The prevalence of PAR and endodontic treatment was not significantly different in individuals with RA compared with control patients.

The Impact of Community Rotations on the Cultural Competence of Dental Hygiene Students in the State of Texas.

Purpose: Culturally competent health care providers understand cultural attitudes, values, beliefs and practices and are able to use this knowledge to guide patient care. Rising oral health disparities among racial and ethnic minorities require that dental educators emphasize the attainment of cultural competence in order to prepare students to effectively care for patients with backgrounds different from their own. This study investigated the role of community rotations on the cultural competence of second-year Texas dental hygiene students.Methods: A modified version of the validated self-assessing Clinical Cultural Competency Questionnaire (CCCQ) was given to students at twelve Texas dental hygiene programs with a 100% response rate (239/239). Data analysis was performed using the Kendall tau correlation for associations and Kruskal-Wallis and Mann-Whitney U tests for differences among and between groups.Results: Students scored highest in attitude (86th percentile). Time spent in community rotations (p=0.009), number of community rotations (p=0.028), racial/ethnic diversity of program clinic patients (p=0.042), and training hours (p=0.044) were associated with increased cultural competence scores. Students with over 50 community rotation hours (p=0.006) scored significantly higher than students with less than 50 hours. Generally, those with four rotations (p=0.002) scored highest. Those with public clinic (p=0.049) and school (p=0.044) rotations scored significantly higher than those without these experiences. Those with nursing home (p=0.009) and hospital (p=0.026) experience scored lower than those without these experiences. Students seeing the most racially/ethnically diverse patients in program clinics scored higher (p=0.014) than students seeing less diverse patients. Those with 6-10 training hours scored higher (p=0.013) than those with other training levels. Hispanics scored significantly higher than whites in skill and overall cultural competence (p≤ 0.005).Conclusion: Dental hygiene programs should invest time in cultural competence training and choose a robust program of community rotations, while considering the diversity of the student body and clinic patient pool to enhance graduates' cultural competence.

A practice-based evaluation of the prevalence and predisposing etiology of white spot lesions.

OBJECTIVE: To use an alumni-centered, practice-based research network to evaluate white spot lesions (WSLs) among treated orthodontic patients. MATERIALS AND METHODS: An initial survey was conducted to ascertain whether orthodontic alumni from Texas A&M University Baylor College of Dentistry were willing to participate. Twenty randomly selected alumni participated, providing 158 treated cases. Each alumnus (1) obtained internal review board consent; (2) submitted pre- and posttreatment photographs of 10 consecutively finished cases; (3) completed a treatment survey; and (4) had the patient/parent complete the American Dental Association (ADA) Caries Risk Assessment. RESULTS: Almost 90% of the alumni surveyed were willing to participate in the practice-based research, primarily because a fellow alumnus asked them to. Approximately 28% of the patients developed WSLs. The average patient developed 2.4 white spots, affecting 12.7% of the teeth examined. WSLs were significantly (P < .001) more (2.3-3.2 times) likely for patients who were identified on the ADA Caries Risk Assessment. The risk of developing WSLs during treatment was also increased for those with fair (2.7 times) or poor (3.5 times) oral hygiene, poor gingival health (2.3 times), and extended treatment times (2.1 times). CONCLUSIONS: There is a substantial risk of developing WSLs among private practice patients, depending partially on the length of treatment. Patients at greatest risk can be identified prior to treatment based on the ADA Caries Risk Assessment, oral hygiene, and gingival health.

Analysis of the Size and Position of the Mental Foramen Using the CS 9000 Cone-beam Computed Tomographic Unit.

INTRODUCTION: The mental foramen (MF) houses vital neurovascular structures, thus making it an anatomic landmark of great importance for many dental procedures. Because the size and position of the MF can vary, proper planning is necessary beforehand to prepare the strategy of treatment. The purpose of this retrospective observational study was to determine and compare the size and position of the MF using the CS 9000 CBCT unit (Carestream Dental, Rochester, NY) to the findings from similar studies. METHODS: Tangential, axial, and coronal CBCT images of 106 patients were retrospectively evaluated to determine the size and position of the MF with respect to the mandibular second premolar apex and the cementoenamel junction. Distinguishing characteristics of sex, age, and race were evaluated. RESULTS: Regarding location, 53.7% of the MFs were located mesial, 45.3% distal, and 1% coincident to the apex of the mandibular second premolar. Males had a significantly greater coronal height and tangential height measurement than females. Black patients had a significantly greater distal horizontal distance from the cementoenamel junction than white patients. The mean width of the MF was 4.08 mm (axial) or 4.12 mm (tangential), whereas the mean height was 3.54 mm (tangential) or 3.55 mm (coronal). CONCLUSIONS: The present study shows that the size and position of the MF can be reliably measured using limited field of view CBCT technology. The findings are similar to previous studies when considering the averages and ranges of the measurements.

The winds of change revisited: progress towards building a culture of evidence-based dentistry.

In 2008, Texas A&M University Baylor College of Dentistry launched a comprehensive four-year curriculum in evidence-based dentistry (EBD) along with a series of faculty development initiatives to create an EBD culture. The aim of this study was to determine the institution's success in achieving this goal. The assessment tool used was the PEAK instrument, which measures respondents' EBD Practices, Experience, Attitudes, and Knowledge. Two EBD-trained classes of students and one class untrained in EBD (approximately 100 students in each class) were assessed annually. The faculty were assessed before and after completion of the initiative. Nearly all students responded, with samples ranging from 87 to 102; the faculty response rates were 53% (62/117) in 2009 and 66% in 2013 (81/123). In the results, the trained students scored significantly higher in knowledge than the untrained students at each of the first three PEAK administrations (p≤0.001). Regarding confidence in appraising a research report, the first trained group significantly gained in appropriate use of statistical tests (p<0.001), while the second trained group significantly gained in this aspect and five others (p≤0.032). At the final PEAK administration, the second trained group agreed more than the untrained group that EBD was important for the practice of dentistry (p<0.001). Faculty comfort level with reading peer-reviewed articles increased significantly from 2009 to 2013 (p=0.039). Faculty members who participated in the summer EBD Fundamentals course (n=28) had significantly higher EBD knowledge scores than those who did not participate (p=0.013), and their EBD attitudes and practices were more positive (p<0.05). Students and faculty trained in EBD were more knowledgeable and exhibited more positive attitudes, supporting a conclusion that the college has made substantial progress towards achieving an EBD culture.

Implementation of Hills' growth curve analysis for unequal-time intervals using GAUSS.

Longitudinal data are widely regarded as the most efficient and informative type of data with which to investigate growth. Paradoxically, appropriate statistical methods for analyzing longitudinal data have been unavailable; with the exception of a computer program for executing Rao's (Biometrika 46:49-58, 1959) one-sample polynomial growth curve analysis (Schneiderman and Kowalski, Am. J. Phys. Anthropol. 67:323-333, 1985) and another applying the Preece-Baines function (Brown and Townsend, Ann. Hum. Biol. 9:495-505, 1982), no programs for analyzing longitudinal data are generally available to the scientific community. Whereas much of the pediatrically oriented work has involved fitting growth curves for individual children, the concern here is the estimation of growth trends for populations. An Adequate understanding of average tendencies is a prerequisite to understanding the growth of individuals. The present paper implements Hills' (Biometrics 24:189-196, 1968) analysis, which is formally equivalent to Rao's but uses finite differences instead of orthogonal polynomials. This method is suitable for data collected at unequal time points and generates explicit measures of velocity and acceleration. The polynomial specification of the curve that best fits the data is also determined with this method. An additional advantage of this approach is that it is conceptually simpler than the classic model of Rao. An application of this method is given using the same craniofacial growth data as in our earlier (1985) paper for comparability. We provide an easy to use program written in GAU's (Edlefson and Jones, Kent, WA; Applied Technical Systems, 1985), a matrix programming language that runs on PC-compatible microcomputers. This implementation for PCs extends the accessibility to investigators who may not have access to mainframe computers.

A GAUSS program for computing an index of tracking from longitudinal observations.

Tracking can be defined as the tendency of individuals or collections of individuals to stay within a particular course of growth over time relative to other individuals. Thus, tracking describes stability in growth patterns. This paper outlines a statistical procedure for examining tracking in a single sample of measurements made on humans or other animals. This nonparametric procedure, based on Cohen's (1960) kappa statistic, is suitable for equally or unequally spaced serial data that is complete and is appropriate for questions concerning growth as well as other time-dependent phenomena. It is a conceptually simple longitudinal method that affords insight regarding the predictability of growth within a population. For example, by tracking, one can ask if young children who are in the lowest height for age category are likely to end up in that category at an older age. A user-friendly GAUSS program is provided that generates overall as well as individual and track-specific statistics. High-resolution graphic representations of the data are also generated by the program. Examples are presented, including a tracking analysis of Guatemalan Indian children using quartiles.

PC program for obtaining orthogonal polynomial regression coefficients for use in longitudinal data analysis.

Much of longitudinal data analysis begins with dimensionality reduction, i.e., the replacement of the T observations x1 , x2 , …, xT on an individual taken at times t1 , t2 , …, tT (not necessarily equally spaced) by a smaller number, P, of parameters which are then used to describe and compare growth processes. We focus on the class of polynomial growth curve models for one-sample data matrices in which the P regression coefficients are estimated by an equation of the form \documentclass{article}\pagestyle{empty}\begin{document}$ \hat \tau = ({\rm W'W}) $\end{document} 1 W'x and consider the choice of the design matrix W. The case in favor of using orthogonal polynomials to comprise the elements of W and provide a PC program, written in GAUSS, for obtaining them is presented. This program can be used instead of existing tables of orthogonal polynomials in the case of equally spaced time points, and to avoid laborious hand-computation to obtain them when the time points are not equally spaced. The program also computes the corresponding orthogonal polynomial regression coefficients \documentclass{article}\pagestyle{empty}\begin{document}$ \hat \alpha = (\Phi '\Phi)^{ - 1} \Phi '{\rm x} $\end{document}, where Φ consists of orthogonal polynomials, which may then be input into other programs for subsequent analysis, e.g., to compare the growth profiles of several groups of individuals. Examples of the use of the program are given. Information on obtaining a copy of the program is provided in Appendix A. © 1992 Wiley-Liss, Inc.

PC program for analyzing one-sample longitudinal data sets which satisfy the two-stage polynomial growth curve model.

The two-stage polynomial growth curve model is described and a GAUSS program to perform the associated computations is documented and made available to interested readers. The two-stage model is similar to that considered by us earlier (Schneiderman and Kowalski: American Journal of Physical Anthropology 67:323-333, 1985; American Journal of Human Biology 1:31-42, 1989), i.e., it is appropriate for the analysis of one-sample longitudinal data collected at either equal or unequal time intervals. Here, however, the covariance matrix, Σ, instead of being considered arbitrary, is now assumed to have the special structure Σ = W A W' + σ2 I. We show the conditions under which this special structure may be expected to arise and how it may be exploited to produce sharper results in certain situations. The method and the program are illustrated and the results are contrasted to those obtained when Σ is arbitrary. It is suggested that the two-stage model is more efficient when the same degree polynomial is adequate to model the data in the two situations, but that, should a higher degree be necessary for the two-stage model, confidence intervals and/or bands may be wider than those corresponding to Σ arbitrary.

Computation of Foulkes and Davis' nonparametric tracking index using GAUSS.

Foulkes and Davis (1981) define tracking as the maintenance of relative rank over a given time span. This paper outlines the development of their statistic, based on a set of individual growth profiles, which estimates the degree of tracking observed in a one-sample longitudinal data set and shows how confidence intervals for the corresponding population parameter may be constructed. An example using a measure of skeletal growth is given and a GAUSS program to do the computations is provided. (Information on obtaining the GAUSS program is provided in the Appendix.) Properties of this statistical approach to tracking are contrasted with another non-parametric method based on Cohen's kappa statistic. © 1992 Wiley-Liss, Inc.

PC program for comparing tracking indices in several independent groups.

A method for computing a measure of tracking based on Cohen's kappa statistic for one-sample longitudinal data sets was previously described and implemented. This paper shows how one may test the equality of several kappas, each computed from an independent longitudinal sample. Thus, it is possible to formally compare groups of individuals with regard to stability in growth (or adaptive) patterns. Relative assessments of predictability in growth outcomes in different populations can be made with this approach. Also, when a common value of kappa is not contradicted by the data, a method to estimate this value and obtain a confidence interval for it is shown. A menu-driven GAUSS program for carrying out the procedure is described and made available. The method and program are illustrated with three samples of Guatemalan children. © 1992 Wiley-Liss, Inc.

Using research for clinical decision-making: evaluating a research report.

Oral healthcare professionals need to ascertain the quality of journals and to read articles critically, distinguishing good from poor research. The oral health practitioner must continually review dental research articles to learn about new options for therapy and oral health products. How does the practitioner know when he/she should incorporate these new procedures into their practice? This continuing education course will present guidelines for critically evaluating the research and for making decisions about how to apply the research findings to clinical practice.

Dimensions of oral care management in Texas hospitals.

PURPOSE: There is a growing body of evidence that suggests improved oral health can help patient outcomes in hospitals. Yet there are indicators that oral care in hospitals is less than ideal. This study was conducted to quantify and qualify the dimensions of oral care in Texas hospitals with a focus on the dental knowledge, attitudes and practices of nurses and barriers to providing such care. METHODS: A random sample of 582 registered nurses, licensed and employed in Texas, was surveyed about oral care attitudes, practices and knowledge. Frequencies and Spearman correlations were used to describe and analyze the data with SPSS. RESULTS: Ninety-eight respondents returned surveys for a 16.8% response rate. Of these, 52% reported their nursing education did not ("minimally/not at all") prepare them for oral care management. However, they felt oral health was important (95%), felt responsible for oral care (79%) and assessed the oral cavity of their patients (78.6%). Although they reported being "knowledgeable" or "very knowledgeable" about oral health management (67%), their score on the knowledge questions was low (mean=51%, sd=0.132). There was not a significant correlation between the knowledge scores and education levels (ρ=0.136, p>0.05) or knowledge scores and work areas (ρ=-0.080, p>0.05). They also reported such barriers as low priority for oral care, lack of time, no mandate and the need for more resources. CONCLUSION: This study revealed that nurses experienced a disconnect between feeling responsible yet somewhat incapable and/or ill-prepared to provide adequate oral care for their patients. This suggests a possible need for revising nurse education, hospital requirements and protocols for performing oral care and employing dental professionals in hospitals.