The future of faculty recruitment: Inspiring students into an academic career.

The dilemma surrounding faculty shortages within dental education continues to present significant challenges for the dental profession. There remains a tremendous need to create an effective and sustainable pathway for the recruitment of faculty into dental academia, with an emphasis on the establishment of a more diverse and representative faculty composition. This perspective paper proposes a blueprint to nurture and inspire dental students into academia.

Prediction of the Post-Pubertal Mandibular Length and Y Axis of Growth by Using Various Machine Learning Techniques: A Retrospective Longitudinal Study.

The aim was to predict the post-pubertal mandibular length and Y axis of growth in males by using various machine learning (ML) techniques. Cephalometric data obtained from 163 males with Class I Angle malocclusion, were used to train various ML algorithms. Analysis of variances (ANOVA) was used to compare the differences between predicted and actual measurements among methods and between time points. All the algorithms revealed an accuracy range from 95.80% to 97.64% while predicting post-pubertal mandibular length. When predicting the Y axis of growth, accuracies ranged from 96.60% to 98.34%. There was no significant interaction between methods and time points used for predicting the mandibular length (p = 0.235) and Y axis of growth (p = 0.549). All tested ML algorithms accurately predicted the post-pubertal mandibular length and Y axis of growth. The best predictors for the mandibular length were mandibular and maxillary lengths, and lower face height, while they were Y axis of growth, lower face height, and mandibular plane angle for the post-pubertal Y axis of growth. No significant difference was found among the accuracies of the techniques, except the least squares method had a significantly larger error than all others in predicting the Y axis of growth.

Objective characterization of dental occlusal and fissure morphologies: Method development and exploratory analysis.

OBJECTIVE: To develop clinically applicable methods to characterize occlusal topography and assess possible associations between morphology and caries incidence and development. DESIGN: In this retrospective clinical study, we evaluated caries presence and severity pre- and post-orthodontic treatment for first molars of 147 patients (384 teeth). These teeth were previously scanned using a clinical intraoral scanner, and the obtained digital elevation models were used to 1) analyze the 3D occlusal surface parameters (n = 384) and 2) quantitatively characterize the mandibular molars' (n = 166) fissure patterns using three novel methods. Pearson correlation coefficients were calculated to evaluate the associations among the measurements, and presence/severity of caries pre- and post-treatment were assessed using generalized linear mixed-effects models. RESULTS: Robust quantitative fissure characterizations were developed, and reliable occlusal surface parameters were obtained. In the studied population, none of the parametric measurements (Slope: p = 0.62 for presence, p = 0.96 for severity; Relief Index (RFI): p = 0.36, p = 0.84; Orientation Patch Count rotated (OPCr): p = 0.48, p = 0.13; Dirichlet Normal Energy (DNE): p = 0.91, p = 0.15) or the fissure morphological measurements (Mesial Angle: p = 0.43; Distal Angle: p = 0.86; Average Angle: p = 0.52; Area Difference: p = 0.83; Percent Fissure: p = 0.68) were found to be significantly associated with caries status or severity. CONCLUSION: Despite the lack of correlation in the limited studied sample, the tools developed to characterize occlusal surface topography and fissure morphology have the potential to be used in more comprehensive clinical evaluations.

The TMD-7 as a Brief Measure for Assessing Temporomandibular Disorder.

OBJECTIVES: The aim of this cross-sectional prospective study was to determine the internal consistency of the TMD-7, and compare prevalence of TMD symptoms in an adult population. MATERIALS AND METHODS: Upon presenting to the orthodontic screening appointment, a total of 440 subjects (316 females and 124 males) were asked to complete the TMD-7 questionnaire. A total of 108 of the participants were later excluded from the study either due to the duplicate or missing responses. The final sample consisted of data from 332 participants (232 females and 100 males), aged between 18 and 64 (mean age: 42.9 ± 9.0) years. STATISTICAL ANALYSIS: Cronbach's α statistics were calculated to assess internal consistency. Comparisons between genders, among age categories, and between subjects with versus without prior orthodontic treatment were performed using Wilcoxon ranks sum and Kruskal-Wallis tests. Comparisons for differences in the individual TMD-7 item ratings were performed using Mantel-Haenszel chi-square tests for ordered categorical responses. RESULTS: The calculated Cronbach's α for TMD-7 scale was 0.77. No statistically significant differences were found in the TMD-7 scale score or the individual TMD-7 item ratings between age categories (p = 0.993). Females had significantly higher TMD-7 scale score and higher ratings for headache, pain in jaw, pain in neck, pain in forehead, difficulty opening mouth, and difficulty while eating (p < 0.05). No statistically significant differences were found in the TMD-7 scale score or the individual TMD-7 item ratings between subjects with versus without previous orthodontic treatment (p = 0.075). CONCLUSION: The TMD-7 tool has good internal consistency and can be used reliably for assessment of TMD symptoms in adults. The use of this tool revealed no significant differences between age groups or between subjects with or without previous orthodontic treatment. However, a significant female gender predisposition for TMD symptoms in the adulthood was determined.

Orthodontic and oral health literacy in adults.

OBJECTIVE: The primary aim of the study was to determine levels of literacy in both oral health and orthodontics in an adult population. The secondary study aim was to investigate differences in literacy between males and females. METHODS: Participants included individuals 18 years or older seeking dental treatment at the East Carolina University (ECU) School of Dental Medicine. To determine levels of oral health literacy (OHL) and orthodontic literacy (OrthoL), validated instruments were administered, including the Rapid Estimate of Adult Literacy in Medicine and Dentistry, the Oral Health Literacy Instrument and its separate scales, and a questionnaire on orthodontic literacy. Summary statistics were computed, and statistical significance was set at 0.05. RESULTS: One hundred seventy-two individuals participated in the study and had a mean age of 55.03 (range:18-88). Greater than 70% of the sampled population exhibited inadequate or marginal oral health knowledge. Additionally, greater than 70% of the sample possessed no more than an 8th grade reading level, with regard to basic medical and dental terms. Higher education was weakly associated with higher OrthoL and OHL. Higher age was also weakly associated with lower OrthoL and OHL. Males on average exhibited significantly higher OHL (p < .05) but there were no OrthoL differences between males and females. Dental visit frequency was not associated with OrthoL or OHL. CONCLUSION: Low levels of OrthoL and OHL were observed in the study. While males demonstrated a higher level of OHL than females, neither age nor the occurrence of dental appointments significantly influenced levels of literacy.

The impact of dental curriculum format on student performance on the national board dental examination.

PURPOSE/OBJECTIVE: The effectiveness of different curriculum types has long been debated by dental educators aiming to provide the best education possible to their students. This study aimed to evaluate the effect of curriculum type (hybrid problem-based learning [PBL] vs. traditional) on National Board Dental Examination (NBDE) part I and II pass rates METHODS: A retrospective cohort study was conducted with a hybrid PBL cohort and traditional cohort. NBDE part I and II pass rates for the two cohorts were acquired, along with demographic and scholastic variables. Pass rates, scholastic variables, and demographic variables were compared using two-sample t-tests and chi-square tests. Associations of the variables with pass rates were analyzed using logistic regression. Significance was set at 5% RESULTS: No significant differences in pass rates for NBDE part I and II were observed between the cohorts. Cumulative dental school grade point average (GPA) was found to be an independent predictor of success for NBDE part I (odds ratio (OR): 1.40, 1.24-1.59 for 0.1 point intervals) and II (OR: 1.34, 1.18-1.52 for 0.1 point intervals), (p < 0.01). DAT biology sub-score was found to be predictive of success for NBDE part I (OR: 1.58, 1.14-2.19), (p = 0.01) CONCLUSIONS: No significant difference in NBDE part I and II pass rates between the cohorts was found. Dental school GPA was the most predictive variable for success on NBDE part I and II. These findings may be helpful considerations as institutions assess the structure of their school curricula.

The impact of the COVID-19 pandemic on U.S. orthodontic practices in 2020.

INTRODUCTION: This study aimed to investigate the immediate impact and long-term implications of severe acute respiratory syndrome coronavirus on orthodontic practices in the United States in 2020. METHODS: A 35-item survey was developed and validated to investigate the impact of the coronavirus disease (COVID-19) pandemic on the orthodontic specialty. The survey contained 5 domains, including respondent's demographic information, COVID-19 information acquisition, practice ramifications of the COVID-19 pandemic, financial implications of the COVID-19 pandemic, and patient management strategies during the COVID-19 pandemic. This voluntary survey acquired responses from active orthodontists in the United States. Associations of demographic and practice characteristics with items related to COVID-19 were assessed using chi-square tests, with a 5% significance level. RESULTS: The survey was disseminated to 5,694 orthodontists, and 507 complete surveys were obtained (response rate of 8.9%). Respondents indicated that they obtained the most useful information regarding the COVID-19 pandemic through professional associations and internet or online news resources. However, 30% of the orthodontists believed information regarding personal financial guidelines was lacking. Most respondents identified delayed treatment progress and temporary staff layoffs as the 2 most negative ramifications of mandated office closures. Approximately 93% of practices applied for and used some sort of stimulus funding offered through the Coronavirus Aid, Relief, and Economic Security Act. Respondents indicated that the COVID-19 related office closures resulted in an average of 50% decrease in net revenue. CONCLUSIONS: The survey found that the COVID-19 pandemic had a broad and significant impact on patient care and financial aspects of U.S. orthodontic practices in 2020. Although generally accepting of the federal and state recommendations, respondents appeared to desire more guidance during the early phase of the pandemic.

Correlation between Advanced Dental Admission Test performance and dental MATCH success.

PURPOSE/OBJECTIVES: The Advanced Dental Admissions Test was developed in 2016 to aid residency programs evaluate qualified applicants. Since its conception, however, there have been no studies seeking to evaluate the usefulness of the exam regarding an applicants' ability to match with a residency program through the Postdoctoral Dental Matching Program (MATCH). The aim of this study was to evaluate the impact of the Advanced Dental Admission Test performance on student MATCH success into a post-doctoral pediatric residency program. METHODS: This retrospective study evaluated the academic records of pediatric residency applicants using the ADEA PASS and MATCH program between 2017 and 2019. Five scholastic and 7 demographic variables were extracted from student ADEA PASS applications. Applicant MATCH status and preference was obtained from the Postdoctoral Dental Matching Program. Descriptive statistics for each application cycle was calculated and used to evaluate applicant demographic and scholastic data. Correlation coefficients assessed for associations between scholastic/demographic factors and MATCH status/preference. Logistic regression models estimated the probability of MATCH status/preference. Significance was set at 5%. RESULTS: An association was found between ADAT scores and MATCH status, but the influence was minimal (odds ratio: 1.004, 95% confidence interval: 1.001-1.008). Applicant age (P < 0.0216) and dental schools that ranked students (P < 0.0002) were the most significant factors for MATCH status and preference, respectively. CONCLUSIONS: ADAT scores played a minimal role in applicants matching to pediatric residency programs. Applicant age and schools that provide class ranks were found to be significant predictors when considering MATCH status and preference to pediatric residency programs.

A visual evaluation of oral plaque removal utilizing an adjunct enzyme pre-rinse in orthodontic subjects.

OBJECTIVE: To determine if an adjunct proteolytic pre-rinse along with contemporary methods of dental cleaning may more effectively remove visual plaque in subjects with fixed orthodontic appliances. MATERIALS AND METHODS: Forty-three orthodontic subjects, ages 10 to 25, completed this single site, double-blind, crossover clinical trial. Subjects randomly received bromelain enzyme or a powdered-sugar placebo pre-rinse, followed by manual tooth brushing and use of a Waterpik. Subjects received the alternate pre-rinse during the subsequent visit. Baseline and residual plaque accumulation were recorded via disclosing tablet and digital photography. A single, blinded examiner scored visual plaque scores from randomized photographs. Treatment effects on composite plaque score were evaluated using repeated-measures analysis of variance. A 5% significance level was used for all tests. RESULTS: No significant differences in plaque scores were noted at baseline or post-rinse between the enzyme and placebo. The changes from baseline to post-rinse (P = .190), post-brushing (P = .764), and post-Waterpik (P = .882) were not significantly different between interventions. Significant reduction in plaque scores were observed in both arms of the study after brushing (P < .01) and waterjet use (P < .01). Neither age (P = .220) nor gender (P = .449) impacted plaque scores. CONCLUSIONS: Use of a bromelain enzyme pre-rinse alone did not significantly enhance plaque removal. A significant reduction in retained plaque was observed with the application of brushing and or Waterpik.

Is There a Correlation Between Airway Volume and Maximum Constriction Area Location in Different Dentofacial Deformities?

PURPOSE: The purpose of the present study was to correlate the airway volume and maximum constriction area (MCA) with the type of dentofacial deformity in patients who required orthognathic surgery. MATERIALS AND METHODS: The present retrospective cohort study included orthognathic surgery patients selected from the private practice of one of us. The selected cases were stratified into 5 different groups according to the clinical and cephalometric diagnosis of their dentofacial deformity. The preoperative airway volume and anatomic location of the MCA were calculated using the airway tool of the Dolphin Imaging software module (Dolphin Imaging and Management Solutions, Chatsworth, CA) and correlated with the diagnosed dentofacial deformity. Differences in the pretreatment airway volumes and MCA location were compared among the deformities. RESULTS: The MCA location was more often the nasopharynx for maxillary deficiency and the oropharynx for mandibular deficiency deformities. The nasopharynx volume was significantly smaller statistically (P < .005) for maxillary deficiency plus mandibular excess compared with mandibular deficiency. The hypopharynx volume was significantly smaller statistically (P < .005) for vertical maxillary excess plus mandibular deficiency than for both maxillary deficiency and maxillary deficiency plus mandibular excess. No statistically significant difference was found among the different deformity groups in relation to the mean airway volume (P > .005). CONCLUSIONS: The location of the airway MCA seems to have a strong correlation with the horizontal position of the maxilla and mandible. The MCA in maxillary deficiencies (isolated or combined) was in the nasopharynx, and the MCA in mandibular deficiencies (isolated or combined) was in the oropharynx. Clinicians should consider these anatomic findings when planning the location and magnitude of orthognathic surgery movements to optimize the outcomes.

Precision of the virtual occlusal record.

OBJECTIVES: To evaluate the precision of the virtual occlusal record using the Carestream CS3600 Intraoral Scanner (Carestream Dental, Atlanta, Ga). MATERIALS AND METHODS: A total of 20 participants were recruited for this prospective study using preestablished inclusion/exclusion criteria. A complete intraoral scan and two bite registrations were obtained. The participants were instructed to bite with normal pressure when bite registrations were acquired. Contact locations, size (circumference), and intensity were identified on the maxillary first molars and canines. Agreement between contact size and intensity was assessed with intraclass correlation coefficients. Kappa statistics evaluated agreement in contact locations. Statistical significance was set at P < .05. RESULTS: All participant data were included for statistical analysis. Between the two bite registrations, nonstatistically significant differences were observed in the proportion of locations with contacts (P = .7681). A nonstatistically significant difference (-0.25 mm, P = .8416) in mean contact circumference size was observed. A statistically significant difference in mean contact intensity was observed (P = .0448). When evaluating agreement between the bite registrations, a weak correlation for size (intraclass correlation coefficient = 0.35) and intensity (intraclass correlation coefficient = 0.32) was observed as well as a moderate agreement for contact location (κ coefficient = 0.67). CONCLUSIONS: The findings suggest that the Carestream intraoral scanner software possesses adequate precision when acquiring the location and size of the contacts in bite registrations. The scanner failed to demonstrate adequate precision when acquiring contact intensities in bite registrations. Additional research is warranted to further investigate the precision of virtual occlusal records with currently available software systems.

Predictors of orthodontic residency performance: An assessment of scholastic and demographic selection parameters.

OBJECTIVE: To evaluate the association between resident selection criteria, including Graduate Record Examination (GRE) scores, and student performance in an orthodontic residency program. MATERIALS AND METHODS: This retrospective study evaluated the academic records of 70 orthodontic residency graduates from the Indiana University School of Dentistry. The following demographic and scholastic data were extracted from the student academic records: applicant age, gender, ethnicity, race, country of origin, dental school graduation year, GRE score, and graduate orthodontic grade point average (GPA). In addition, student American Board of Orthodontics (ABO) written examination quintiles were obtained from the ABO. Scatterplots, analysis of variance, and correlation coefficients were used to analyze the data. Statistical significance was established at .05 for the study. RESULTS: No associations were found with any component of the GRE, except with the quantitative GRE section, which displayed a weak association with ABO module 2 scores. Dental school GPA demonstrated weak correlations with all ABO modules and moderate correlations with overall and didactic orthodontic GPAs. When assessing demographic factors, significant differences (P < .05) were observed, with the following groups demonstrating higher performance on certain ABO modules: age (younger), race (whites), and country of origin (US citizens). CONCLUSIONS: Findings suggest the GRE has no association with student performance in an orthodontic residency. However, dental school GPA and/or class rank appear to be the strongest scholastic predictors of residency performance.

Preliminary Performance of the Advanced Dental Admission Test (ADAT): Association Between ADAT Scores and Other Variables for Applicants to Residency Programs at a U.S. Dental School.

Historically, dental residency programs have used numerical assessment criteria to evaluate and identify qualified candidates for admission. Recent elimination of such assessment tools has undermined many programs' holistic evaluation process. The Advanced Dental Admission Test (ADAT) was developed and recently piloted in hopes of addressing this issue. The aim of this study was to evaluate the preliminary performance and validity of the ADAT by exploring the association between ADAT scores and other variables for a sample of applicants to residency programs. The WebAdMIT admissions database was used to identify the test scores and educational and demographic information of 92 individuals who completed the pilot ADAT and were seeking a 2017 postgraduate specialty position at Indiana University School of Dentistry. The results showed that the ADAT had strong to weak correlations with certain applicant variables (p<0.05). No significant differences were found for age, race, school location, or country of origin. However, males performed better than females (p<0.05), and non-Hispanics performed better than Hispanics (p<0.01). ADAT component scores were also higher for individuals with a history of research activity (p<0.05). This study found that significant associations existed between the ADAT and indices typically associated with competitive applicants. These findings suggest that the ADAT may serve as a useful numerical assessment instrument, with the potential to identify high-performing candidates. Furthermore, the ADAT seemed to be a plausible option for programs seeking to incorporate a quantitative assessment instrument as part of a holistic candidate selection process.

Accuracy of three-dimensional dental resin models created by fused deposition modeling, stereolithography, and Polyjet prototype technologies: A comparative study.

OBJECTIVES: The aim of this study was to assess the dimensional accuracy of fused deposition modeling (FDM)-, Polyjet-, and stereolithography (SLA)-produced models by comparing them to traditional plaster casts. MATERIALS AND METHODS: A total of 12 maxillary and mandibular posttreatment orthodontic plaster casts were selected from the archives of the Orthodontic Department at the Indiana University School of Dentistry. Plaster models were scanned, saved as stereolithography files, and printed as physical models using three different three-dimensional (3D) printers: Makerbot Replicator (FDM), 3D Systems SLA 6000 (SLA), and Objet Eden500V (Polyjet). A digital caliper was used to obtain measurements on the original plaster models as well as on the printed resin models. RESULTS: Comparison between the 3D printed models and the plaster casts showed no statistically significant differences in most of the parameters. However, FDM was significantly higher on average than were plaster casts in maxillary left mixed plane (MxL-MP) and mandibular intermolar width (Md-IMW). Polyjet was significantly higher on average than were plaster casts in maxillary intercanine width (Mx-ICW), mandibular intercanine width (Md-ICW), and mandibular left mixed plane (MdL-MP). Polyjet was significantly lower on average than were plaster casts in maxillary right vertical plane (MxR-vertical), maxillary left vertical plane (MxL-vertical), mandibular right anteroposterior plane (MdR-AP), mandibular right vertical plane (MdR-vertical), and mandibular left vertical plane (MdL-vertical). SLA was significantly higher on average than were plaster casts in MxL-MP, Md-ICW, and overbite. SLA was significantly lower on average than were plaster casts in MdR-vertical and MdL-vertical. CONCLUSIONS: Dental models reconstructed by FDM technology had the fewest dimensional measurement differences compared to plaster models.

Microdamage generation by tapered and cylindrical mini-screw implants after pilot drilling.

OBJECTIVE: To investigate the relationship between mini-screw implant (MSI) diameter (1.6 vs 2.0 mm) and shape (tapered vs cylindrical) and the amount of microdamage generated during insertion. MATERIALS AND METHODS: Thirty-six cylindrical and 36 tapered MSIs, 6 mm long, were used in this study. Half of each shape was 1.6 mm in diameter, while the other half was 2.0 mm. After pilot drilling, four and five MSIs were inserted, respectively, into fresh cadaveric maxillae and mandibles of dogs. Bone blocks containing the MSIs were sectioned and ground parallel to the MSI axis. Epifluorescent microscopy was used to measure overall cortical thickness, crack length, and crack number adjacent to the MSI. Crack density and total microdamage burden per surface length were calculated. Three-way analysis of variance (ANOVA) was used to test the effects of jaw, and MSI shape and diameter. Pairwise comparisons were made to control the overall significance level at 5%. RESULTS: The larger (2.0 vs 1.6 mm) cylindrical MSIs increased the numbers, lengths, and densities of microcracks, and the total microdamage burden. The same diameter cylindrical and tapered MSIs generated a similar number of cracks and crack lengths. More total microdamage burden was created by the 2.0-mm cylindrical than the 2.0-mm tapered MSIs. Although higher crack densities were produced by the insertion of 1.6-mm tapered MSIs, there was no difference in total microdamage burden induced by 1.6-mm tapered and 1.6-mm cylindrical MSIs. CONCLUSIONS: Pilot drilling is effective in reducing microdamage during insertion of tapered MSIs. To prevent excessive microdamage, large diameter and cylindrical MSIs should be avoided.

Comparison of stainless steel and titanium alloy orthodontic miniscrew implants: a mechanical and histologic analysis.

INTRODUCTION: The detailed mechanical and histologic properties of stainless steel miniscrew implants used for temporary orthodontic anchorage have not been assessed. Thus, the purpose of this study was to compare them with identically sized titanium alloy miniscrew implants. METHODS: Forty-eight stainless steel and 48 titanium alloy miniscrew implants were inserted into the tibias of 12 rabbits. Insertion torque and primary stability were recorded. One hundred grams of tensile force was applied between half of the implants in each group, resulting in 4 subgroups of 24 specimens each. Fluorochrome labeling was administered at weeks 4 and 5. When the rabbits were euthanized at 6 weeks, stability and removal torque were measured in half (ie, 12 specimens) of each of the 4 subgroups. Microdamage burden and bone-to-implant contact ratio were quantified in the other 12 specimens in each subgroup. Mixed model analysis of variance was used for statistical analysis. RESULTS: All implants were stable at insertion and after 6 weeks. The only significant difference was the higher (9%) insertion torque for stainless steel. No significant differences were found between stainless steel and titanium alloy miniscrew implants in microdamage burden and bone-to-implant contact regardless of loading status. CONCLUSIONS: Stainless steel and titanium alloy miniscrew implants provide the same mechanical stability and similar histologic responses, suggesting that both are suitable for immediate orthodontic clinical loads.

Personality traits as a potential predictor of willingness to undergo various orthodontic treatments.

OBJECTIVE: To establish an association between patient personality traits and potential willingness to undergo various orthodontic treatments. MATERIALS AND METHODS: One hundred adolescent individuals aged 12-16 years completed an anonymous electronic questionnaire via Survey Monkey. The 24-item questionnaire contained three major sections: patient demographics, a modified Big Five Inventory (BFI)-10 personality index, and a willingness to undergo treatment assessment. Multiple-variable linear regression analyses were used to determine the associations among age, gender, ethnicity, and the five personality traits simultaneously with willingness to undergo treatment. Statistical significance was set at P ≤ .05. RESULTS: Ninety-six of the 100 individuals were included in the statistical analysis. Age, ethnicity, and gender failed to correlate with potential willingness to undergo orthodontic treatment. Several personality dimensions within the modified BFI-10 (agreeableness, conscientiousness, and neuroticism) were significantly associated with willingness to undergo various orthodontic treatments (P ≤ .05). Agreeableness demonstrated positive correlations with five treatment modalities, while both conscientiousness and neuroticism exhibited negative associations with a single treatment modality. Openness and extraversion were the only personality dimensions that failed to associate with any of the treatment modalities. Four of the nine treatment modalities had no association with patient demographics or a patient's personality dimensions. CONCLUSIONS: Personality traits are useful in predicting a patient's potential willingness to participate in various orthodontic treatments. The agreeableness dimension provided the most utility in predicting patient willingness. Age, ethnicity, and gender were not significant in predicting patient willingness.

Three-dimensional quantification of pretorqued nickel-titanium wires in edgewise and prescription brackets.

OBJECTIVE: To quantify the three-dimensional moments and forces produced by pretorqued nickel-titanium (NiTi) rectangular archwires fully engaged in 0.018- and 0.022-inch slots of central incisor and molar edgewise and prescription brackets. MATERIALS AND METHODS: Ten identical acrylic dental models with retroclined maxillary incisors were fabricated for bonding with various bracket-wire combinations. Edgewise, Roth, and MBT brackets with 0.018- and 0.022-inch slots were bonded in a simulated 2 × 4 clinical scenario. The left central incisor and molar were sectioned and attached to load cells. Correspondingly sized straight and pretorqued NiTi archwires were ligated to the brackets using 0.010-inch ligatures. Each load cell simultaneously measured three force (Fx, Fy, Fz) and three moment (Mx, My, Mz) components. The faciolingual, mesiodistal, and inciso-occluso/apical axes of the teeth corresponded to the x, y, and z axes of the load cells, respectively. Each wire was removed and retested seven times. Three-way analysis of variance (ANOVA) examined the effects of wire type, wire size, and bracket type on the measured orthodontic load systems. Interactions among the three effects were examined and pair-wise comparisons between significant combinations were performed. RESULTS: The force and moment components on each tooth were quantified according to their local coordinate axes. The three-way ANOVA interaction terms were significant for all force and moment measurements (P < .05), except for Fy (P > .05). CONCLUSION: The pretorqued wire generates a significantly larger incisor facial crown torquing moment in the MBT prescription compared to Roth, edgewise, and the straight NiTi wire.

Orthodontic mini-implant diameter does not affect in-situ linear microcrack generation in the mandible or the maxilla.

INTRODUCTION: Microdamage reduces bone mechanical properties and thus could contribute to implant failure. The objective of this study was to investigate whether the diameter of mini-implants affects linear microcrack generation and whether this differs between the mandible and the maxilla because of their contrasting cortical thicknesses. METHODS: Maxillary and mandibular quadrants of 5 dogs were randomly assigned to receive, in situ, no pilot drilling or mini-implant insertion (control), pilot drilling only without mini-implants, or pilot drilling plus a mini-implant of 1 of 3 diameters: 1.4 mm (n = 18), 1.6 mm (n = 18), and 2.0 mm (n = 18). Linear microcracks were assessed on basic fuchsin-stained sections by using epifluorescence microscopy. RESULTS: Pilot drilling without mini-implant insertion produced significantly higher linear microcrack burdens in the mandible compared with the maxilla. In the both the mandible and the maxilla, all implants produced higher linear microcrack burdens than did the controls, yet there were no differences between the 3 implant diameters. CONCLUSIONS: Neither the diameter of the mini-implant nor the site of insertion (mandible vs maxilla) had a significant effect on the amount of linear microdamage adjacent to the implant when the implants were inserted after pilot drilling in situ.

The effects of varying alcohol concentrations commonly found in mouth rinses on the force decay of elastomeric chain.

OBJECTIVE: To test the effect of alcohol on force decay of elastomeric chains in vitro in order to determine if increasing alcohol concentrations results in an increased amount of elastomeric chain force decay. MATERIALS AND METHODS: A prospective laboratory study was completed to test the effect of alcohol exposure on orthodontic elastomeric chain. A total of 450 specimens were divided into five test groups. Two test groups were each exposed to different alcohol concentrations (14% and 26.9%) and the other two test groups were exposed to different commercially available mouth rinses (Cepacol -14% alcohol and Listerine - 26.9% alcohol) for 60 seconds twice a day. The control group followed all of the same procedures but was only exposed to deionized (DI) water. Force measurements were taken at six time points (initial, 1 day, 7 days, 14 days, 21 days, and 28 days). RESULTS: There were no significant differences among groups at the initial time point (P  =  .52). Statistically significant effects of time on force decay were seen in all groups. All test groups showed significantly more force decay than the control group. Only a few statistically significant differences were observed when comparing force decay among the test groups. CONCLUSIONS: Alcohol causes an increase in force decay of elastomeric chain over time. A concentration dependence of alcohol on force decay of elastomeric chain was not observed.