Accuracy of Dental Monitoring 3D digital dental models using photograph and video mode.

INTRODUCTION: This study aimed to test the accuracy of the 3-dimensional (3D) digital dental models generated by the Dental Monitoring (DM) smartphone application in both photograph and video modes over successive DM examinations in comparison with 3D digital dental models generated by the iTero Element intraoral scanner. METHODS: Ten typodonts with setups of class I malocclusion and comparable severity of anterior crowding were used in the study. iTero Element scans along with DM examination in photograph and video modes were performed before tooth movement and after each set of 10 Invisalign aligners for each typodont. Stereolithography (STL) files generated from the DM examinations in photograph and video modes were superimposed with the STL files from the iTero scans using GOM Inspect software to determine the accuracy of both photograph and video modes of DM technology. RESULTS: No clinically significant differences, according to the American Board of Orthodontics-determined standards, were found. Mean global deviations for the maxillary arch ranged from 0.00149 to 0.02756 mm in photograph mode and from 0.0148 to 0.0256 mm in video mode. Mean global deviations for the mandibular arch ranged from 0.0164 to 0.0275 mm in photograph mode and from 0.0150 to 0.0264 mm in video mode. Statistically significant differences were found between the 3D models generated by the iTero and the DM application in photograph and video modes over successive DM examinations. CONCLUSIONS: 3D digital dental models generated by the DM smartphone application in photograph and video modes are accurate enough to be used for clinical applications.

Effects of unilateral premolar extraction treatment on the dental arch forms of Class II subdivision malocclusions.

INTRODUCTION: A retrospective study evaluating posttreatment symmetry in dental arch form and midlines was carried out in Class II subdivision patients treated with unilateral and bilateral maxillary premolar extractions. METHODS: Using Geomagic (version 14; Geomagic, Research Triangle Park, NC) and MATLAB (version 8.4; MathWorks, Natick, Mass) software, best-fit curves expressed as quartic polynomials were generated for 13 Class II subdivisions treated with unilateral extractions and 20 treated with bilateral maxillary premolar extractions. Transverse and sagittal measurements were recorded to assess symmetry. Dental models were superimposed on constructed reference planes to generate average posttreatment arches. Statistical comparisons were performed with the significance level set at P ≤0.05. RESULTS: The unilateral extraction group showed significant differences in transverse arch forms between the right and left sides in the anterior, anterior-middle, and middle segments of the arch, and all regions other than the posterior segment in the sagittal dimension. Significant differences were found between groups in the anterior and anterior-middle segments of the arch transversely, the middle and middle-posterior segments sagittally, and the midline deviation relative to the midsagittal plane. Superimposed average arches showed similar results. CONCLUSIONS: Unilateral maxillary extraction treatment generally results in a narrower and more posteriorly displaced arch form on the extraction side, with a deviated maxillary midline toward the extraction side of the arch.

Change in the vertical dimension of Class II Division 1 patients after use of cervical or high-pull headgear.

INTRODUCTION: The goals of this study were to compare the effects that cervical and high-pull headgear have on the vertical dimensions in Class II Division 1 patients during phase 1 treatment and to compare these effects with untreated predicted growth for the sample population. METHODS: Pretreatment and posttreatment cephalometric radiographs of children who had undergone Class II Division 1 correction with cervical (n = 22) or high-pull headgear (n = 19) were analyzed for the measurements that describe the changes in the vertical component of growth and mandibular position. The groups were matched for age (mean, 9 ± 2.5 years), treatment time (mean, 14 months), malocclusion, and similar skeletal features. The groups were compared with each other and also with an untreated growth model. RESULTS: Treatment with cervical headgear resulted in smaller increases in measurements that describe the vertical dimension than with high-pull headgear. Cervical headgear showed more favorable changes in mandibular growth that were statistically significant when compared with the untreated growth models. CONCLUSIONS: In this study, the cervical headgear showed more control over the vertical dimension and produced more favorable changes in mandibular position by normalizing the occlusal plane. Compared with the untreated growth model, cervical headgear worked synergistically with growth to produce more optimal changes in mandibular position.

Accuracy of digital American Board of Orthodontics Discrepancy Index measurements.

INTRODUCTION: A digital analysis that is shown to be accurate will ease the demonstration of initial case complexity. To date, no literature exists on the accuracy of the digital American Board of Orthodontics Discrepancy Index (DI) calculations when applied to pretreatment digital models. METHODS: Plaster models were obtained from 45 previous patients with varying degrees of malocclusion. Total DI scores and the target disorders were computed manually with a periodontal probe on the original plaster casts (gold standard) and digitally using Ortho Insight 3D (Motion View Software, Hixson, Tenn) and OrthoCAD (Cadent, Carlstadt, NJ). Intrarater and interrater reliabilities were assessed for 15 subjects using the Spearman rho correlation test. Accuracies of the DI scores and target disorders were assessed for all 45 subjects using Wilcoxon signed ranks tests. RESULTS: Intrarater and interrater reliabilities were high for total DI scores and most target disorders (r > 0.8). No significant difference was found between total DI score when measured with OrthoCAD compared with manual calculations. The total DI scores calculated by Ortho Insight 3D were found to be significantly greater than those by manual calculation by 2.71 points. CONCLUSIONS: The findings indicate that a DI calculated by Ortho Insight 3D may lead the clinician to overestimate case complexity. OrthoCAD's DI module was demonstrated to be a clinically acceptable alternative to manual calculation of the total scores.

Assessment of occlusion curriculum in predoctoral dental education: report from ACP Task Force on Occlusion Education.

PURPOSE: The purposes of this report were to (1) assess the current occlusion curriculum in the predoctoral prosthodontic education of US dental institutions and (2) to examine the opinions of faculty, course directors, and program directors on the contents of occlusion curriculum. MATERIALS AND METHODS: The Task Force on Occlusion Education from the American College of Prosthodontists (ACP) conducted two surveys using a web-based survey engine: one to assess the current status of occlusion education in predoctoral dental education and another to examine the opinions of faculty and course directors on the content of occlusion curriculum. The sections in the surveys included demographic information, general curriculum information, occlusion curriculum for dentate patients, occlusion curriculum for removable prosthodontics, occlusion curriculum for implant prosthodontics, temporomandibular disorder (TMD) curriculum, teaching philosophy, concepts taught, and methods of assessment. The results from the surveys were compiled and analyzed using descriptive statistics. The results from the two surveys on general concepts taught in occlusion curriculum were sorted and compared for discrepancies. RESULTS: According to the predoctoral occlusion curriculum surveys, canine guidance was preferred for dentate patients, fixed prosthodontics, and fixed implant prosthodontics. Bilateral balanced occlusion was preferred for removable prosthodontics and removable implant prosthodontics. There were minor differences between the two surveys regarding the occlusion concepts being taught and the opinions of faculty members teaching occlusion. CONCLUSION: Two surveys were conducted regarding the current concepts being taught in occlusion curriculum and the opinions of educators on what should be taught in occlusion curriculum. An updated and clearly defined curriculum guideline addressing occlusion in fixed prosthodontics, removable prosthodontics, implant prosthodontics, and TMD is needed.

Assessment of Handicapping Labio-Lingual Deviation index scoring methods and their effect on orthodontic treatment coverage by Medicaid.

BACKGROUND: The purpose of this study was to assess the validity and reliability of Handicapping Labio-Lingual Deviation index (HLDI) scoring methods as calculated by digital models (DM) and visual inspection (VI) and their agreement to either meet or fail to meet the Medicaid coverage threshold. An additional objective was to assess the agreement with Medicaid managed care organizations (MCO) coverage decisions. METHODS: The study included the orthodontic records of 401 patients who applied for Medicaid coverage. Two methods were used to calculate HLDI scores: (1) Measurements derived from DMs using OrthoCAD software; and (2) VI of intraoral photographs. The levels of agreement between the two methods and the Medicaid coverage decision by a MCO were evaluated. RESULTS: The study results show a high level of agreement between the two HLDI calculation methods, DM and VI evaluation methods(Cramer's V = 0.812). The agreement on coverage decisions (eligible/not eligible) between VI methods and the official MCO decision was Cramer's V = 0.318. The agreement on coverage decisions between the DM method and the official MCO decision was Cramer's V = 0.318. CONCLUSIONS: MCO assessment results of the patients using HLDI showed low agreement with the results obtained by DM and VI scoring methods used in this study. The Illinois Medicaid system is apparently using unknown factors other than the HLDI score when determining when approving or disapproving orthodontic coverage. PRACTICAL IMPLICATIONS: MCO decisions on eligibility for orthodontic treatment coverage were not consistent with patients' treatment needs.

Salivary microbiome with gastroesophageal reflux disease and treatment.

The effect of oral microbial composition on periodontal health and on systemic health has been, and is being established. The oral microbiome, in turn, can be altered by local and systemic diseases and conditions. Gastroesophageal reflux disease (GERD), has been associated with increased acidity in the oral cavity resulting in dental erosion, and controversially a reduced risk of periodontal disease. We hypothesized that presence of GERD was linked to a modified microbial profile in untreated GERD patients and that the use of proton pump inhibitor (PPI) drugs: potent disruptors of gut microbiome, in GERD patients might result in a salivary microbiome that is further distinct. Untreated GERD patients showed multiple differences in salivary microbiome as compared to healthy controls. Taxa found at lower levels related to the presence of GERD not treated by PPI included: Prevotella melaninogenica, Prevotella pallens, Leptotrichia, and Solobacterium moorei and thirteen others. In contrast, GERD patients chronically using PPI showed minimal differences in salivary taxa compared to healthy controls not using PPI.

How well does Invisalign work? A prospective clinical study evaluating the efficacy of tooth movement with Invisalign.

INTRODUCTION: The purpose of this prospective clinical study was to evaluate the efficacy of tooth movement with removable polyurethane aligners (Invisalign, Align Technology, Santa Clara, Calif). METHODS: The study sample included 37 patients treated with Anterior Invisalign. Four hundred one anterior teeth (198 maxillary and 203 mandibular) were measured on the virtual Treat models. The virtual model of the predicted tooth position was superimposed over the virtual model of the achieved tooth position, created from the posttreatment impression, and the 2 models were superimposed over their stationary posterior teeth by using ToothMeasure, Invisalign's proprietary superimposition software. The amount of tooth movement predicted was compared with the amount achieved after treatment. The types of movements studied were expansion, constriction, intrusion, extrusion, mesiodistal tip, labiolingual tip, and rotation. RESULTS: The mean accuracy of tooth movement with Invisalign was 41%. The most accurate movement was lingual constriction (47.1%), and the least accurate movement was extrusion (29.6%)- specifically, extrusion of the maxillary (18.3%) and mandibular (24.5%) central incisors, followed by mesiodistal tipping of the mandibular canines (26.9%). The accuracy of canine rotation was significantly lower than that of all other teeth, with the exception of the maxillary lateral incisors. At rotational movements greater than 15 degrees, the accuracy of rotation for the maxillary canines fell significantly. Lingual crown tip was significantly more accurate than labial crown tip, particularly for the maxillary incisors. There was no statistical difference in accuracy between maxillary and mandibular teeth of the same tooth type for any movements studied. CONCLUSIONS: We still have much to learn regarding the biomechanics and efficacy of the Invisalign system. A better understanding of Invisalign's ability to move teeth might help the clinician select suitable patients for treatment, guide the proper sequencing of movement, and reduce the need for case refinement.

Preferences for vertical position of the maxillary lateral incisors.

AIM: To evaluate the preferences for vertical position of the maxillary lateral incisors among orthodontists, general dentists, and laypeople. METHODS: The study group consisted of 120 judges, 40 in each of 3 study groups. Judges were asked to give their preference for maxillary lateral incisor position while viewing an animation of an idealized smile. Perceptometrics software animated the photograph and collated responses. Each judge participated in 2 similar experiments, 1 to determine what he/she found to be the most pleasing position and another to define that position's range of acceptability. The processed data were analyzed with ANOVA (analysis of variance) and post-hoc Scheffé tests to determine mean differences among the 3 study groups. RESULTS: The most pleasing protocol revealed no significant difference (P >.05) in the mean preferences of the 3 groups. The average preference was 0.6 mm above the incisal plane. No subjects chose a level incisal plane as being most pleasing. Orthodontists and general dentists had a smaller range of acceptability than laypeople. The means for lower and upper limits of acceptability for all subjects were 0.3 mm and 1.0 mm, respectively, above the incisal plane. CONCLUSIONS: The judges in this study preferred that the maxillary lateral incisor to be set about 0.5 mm above the incisal plane, slightly offset from the incisal plane, and not level. The lateral incisors were best perceived when they were offset slightly from the incisal plane, and there was an acceptable range within which the lateral incisors may be placed.

An evidence-based evaluation of the concept of centric relation in the 21st century.

The concept and application of a temporomandibular joint (TMJ) relationship identified as centric relation (CR) has changed significantly over the past century. Originally proposed as a biologically reasonable position where maxillary and mandibular dentures should occlude, it later was applied to the dentate population as well. The term "ideal" was used by the gnathologic dental community as they sought to define the exact details of CR in terms of condyle-fossa relationships. Assessments of patients' occlusion were then made in relation to CR, and discrepancies between the two positions were described as being problematic. Since not all dentists have accepted this concept, the clinical application of CR has become a topic of major dental confusion and controversy. To further complicate things, the formal definitions of CR have continuously changed over the past 40 years. In this paper, the biologic development of occlusal and TMJ relationships is reviewed, followed by a discussion about the validity of applying CR concepts and procedures in contemporary clinical and research settings. Special attention is devoted to the alleged relationships between occlusion, jaw positions, and temporomandibular disorders (TMDs). Current evidence suggests that it is time to stop applying CR concepts to the evaluation and dental treatment of healthy dentate individuals. For patients with TMDs, it is time to apply current concepts of biopsychosocial assessment and management rather than following the 20th century mechanistic models of fixing dental and skeletal malalignments.

Curriculum restructuring at a North American dental school: rationale for change.

The purpose of this article is to discuss how traditional dental school curricula are inconsistent with research in how learners learn. In the last ten years, there has been considerable discussion about the need for dental education reform, and innovative changes have occurred in the curricula of a number of U.S. dental schools. However, efforts in curriculum restructuring have been hindered by the lack of evidence that one specific curriculum design achieves outcomes superior to other designs. Moreover, there has been little discussion in the dental literature about how modern theories of learning can provide a sound rationale for change in dental education. Thus, it is important for those involved in curriculum reform to present the rationale for change based on the best available evidence. In this review, we summarize aspects of research on learning that seem applicable to dental education and outline ways in which curricula might be changed to become more consistent with the evidence.

Assessment of vertical changes during maxillary expansion using quad helix or bonded rapid maxillary expander.

OBJECTIVE: To determine if there is a significantly different effect on vertical changes during phase I palatal expansion treatment using a quad helix and a bonded rapid maxillary expander in growing skeletal Class I and Class II patients. MATERIALS AND METHODS: This retrospective study looked at 2 treatment groups, a quad helix group and a bonded rapid maxillary expander group, before treatment (T1) and at the completion of phase I treatment (T2). Each treatment group was compared to an untreated predicted growth model. Lateral cephalograms at T1 and T2 were traced and analyzed for changes in vertical dimension. RESULTS: No differences were found between the treatment groups at T1, but significant differences at T2 were found for convexity, lower facial height, total facial height, facial axis, and Frankfort Mandibular Plane Angle (FMA) variables. A comparison of treatment groups at T2 to their respective untreated predicted growth models found a significant difference for the lower facial height variable in the quad helix group and for the upper first molar to palatal plane (U6-PP) variable in the bonded expander group. CONCLUSION: Overall, both the quad helix expander and the bonded rapid maxillary expander showed minimal vertical changes during palatal expansion treatment. The differences at T2 suggested that the quad helix expander had more control over skeletal vertical measurements. When comparing treatment results to untreated predicted growth values, the quad helix expander appeared to better maintain lower facial height and the bonded rapid maxillary expander appeared to better maintain the maxillary first molar vertical height.

Treating temporomandibular disorders with permanent mandibular repositioning: is it medically necessary?

In this paper, the authors review the rationale and history of mandibular repositioning procedures in relation to temporomandibular disorders (TMDs) as these procedures have evolved over time. A large body of clinical research evidence shows that most TMDs can and should be managed with conservative treatment protocols that do not include any mandibular repositioning procedures. Although this provides a strong clinical argument for avoiding such procedures, very few reports have discussed the biologic reasons for either accepting or rejecting them. This scientific information could provide a basis for determining whether mandibular repositioning procedures can be defended as being medically necessary. This position paper introduces the biologic concept of homeostasis as it applies to this topic. The continuing adaptability of teeth, muscles, and temporomandibular joints throughout life is described in terms of homeostasis, which leads to the conclusion that each person's current temporomandibular joint position is biologically "correct." Therefore, that position does not need to be changed as part of a TMD treatment protocol. This means that irreversible TMD treatment procedures, such as equilibration, orthodontics, full-mouth reconstruction, and orthognathic surgery, cannot be defended as being medically necessary.

A comparison of compliance in Medicaid versus non-Medicaid patients.

BACKGROUND: Medicaid patients have been associated with lack of compliance during their orthodontic treatment in comparison with the non-Medicaid patients. In this study, Medicaid and non-Medicaid orthodontic patients' compliance from a state university and private practice orthodontic clinic within close location were analyzed. METHODS: Charts of 30 Medicaid and 30 non-Medicaid orthodontic patients at each orthodontic clinic were reviewed. From each chart, mean percentage of failed and late appointments, number of broken appliances, number of comments on compliance with auxiliary wear and number of comments on oral hygiene maintenance were recorded. RESULTS: Statistically significant differences between Medicaid and non-Medicaid orthodontic patients were not found. CONCLUSIONS: The results of this study indicated that in general there are no differences between Medicaid and non-Medicaid orthodontic patients. PRACTICAL IMPLICATIONS: These results may alleviate the doubts of the dental practitioner in treating Medicaid patients.

Teaching clinically relevant dental anatomy in the dental curriculum: description and assessment of an innovative module.

The primary objective of the preclinical dental anatomy course in the predoctoral dental curriculum is to introduce students to cognitive and psychomotor skills related to the morphology and spatial and functional relationships of human dentition. Traditionally, didactic content for the subject is found in textbooks and course manuals and summarized by the faculty in lectures to the entire class. Psychomotor skills associated with recognition and reproduction of tooth morphology are traditionally learned by examining preserved tooth specimens and their cross-sections, combined with producing two-dimensional line drawings and carving teeth from wax blocks. These activities have little direct clinical application. In most cases, students are passive in the learning process, and assessment of student performance is unilateral and subjective. A recently revised dental anatomy module at the University of Illinois at Chicago College of Dentistry integrates independent class preparation with active small-group discussion and patient scenario-based wax-up exercises to replace missing tooth structure on manikin teeth. The goal of the revision is to shift emphasis away from decontextualized technical learning toward more active and clinically applicable learning that improves conceptual understanding while contributing to early acquisition of psychomotor skills. This article describes the rationale, components, and advantages of the revised module and presents a pre-post comparison of student learning outcomes for three class cohorts (N=203).

Evaluation of incisor position and dental transverse dimensional changes using the Damon system.

OBJECTIVES: To test the hypotheses that the Damon system will maintain intercanine, interpremolar, and intermolar widths. To test subsequent hypotheses that the Damon system will not produce a significant difference in maxillary and mandibular incisor position/angulation when compared with control groups treated with conventional fixed orthodontic appliances for similar malocclusion. MATERIALS AND METHODS: Subjects treated with the Damon system (N  =  27) were compared with subjects treated with a conventionally ligated edgewise bracket system (N  =  16). Subjects' pretreatment and posttreatment lateral cephalometric radiographs and dental models were scanned, measured, and compared to see whether significant differences exist between time points and between the two groups. RESULTS: Results did not support the claimed lip bumper effect of the Damon system and showed similar patterns of crowding alleviation, including transverse expansion and incisor advancement, in both groups, regardless of the bracket system used. CONCLUSIONS: Maxillary and mandibular intercanine, interpremolar, and intermolar widths increased significantly after treatment with the Damon system. The mandibular incisors were significantly advanced and proclined after treatment with the Damon system, contradicting the lip bumper theory of Damon. Posttreatment incisor inclinations did not differ significantly between the Damon group and the control group. Patients treated with the Damon system completed treatment on average 2 months faster than patients treated with a conventionally ligated standard edgewise bracket system.

A clinically oriented complete denture program for second-year dental students.

The traditional preclinical complete denture prosthodontic curriculum relies predominantly on the laboratory (e.g., bench-type) component of the complete denture fabrication process. In most cases, this involves a passive model of student knowledge acquisition utilizing lectures and low-fidelity laboratory exercises. A recently implemented program in the College of Dentistry at the University of Illinois at Chicago challenges this educational paradigm by introducing an active learning environment for second-year students based on significant clinical exposure with patients. The result is a major shift of emphasis, first, from a purely technical/laboratory aspect of the discipline to patient-centered education and, second, from mastering individual phases of denture fabrication to understanding the entire process of edentulous patient care. To compare student outcomes in the new program with those in the traditional program, their performance overall and in three components of the final examination for each program were statistically compared. The results of the one-way ANOVA analysis show statistically significant improvement in the students' total score in the new program, including their performance on the written, practical, and OSCE portions of the final examination. This article describes the rationale, logistics, challenges, and advantages of the new educational model of the complete denture prosthodontics curriculum.

Organization and function of the collagen fiber system in the human temporomandibular joint disk and its attachments.

The collagen fiber organization in the anterior band (AB), intermediate zone (IZ) and posterior band (PB) of the disk of the human jaw joint disk and in its attachments was studied under the polarizing microscope. Observations were made on serially sectioned joints (n = 6) and three sets of disk samples sectioned along mutually perpendicular planes (n = 21). The collagen fiber bundles in all disk regions branch and join or are decussated with other bundles. The fibers of the IZ were oriented generally parallel to the disk surfaces. Most of these fibers extend into the AB and PB where they either join with transverse or vertically oriented fiber groups or pass through the bands into the disk attachments. The lateral branching/decussation angles of fibers in the IZ and adjacent regions of the AB and PB were measured in the central region of four disks. The mean angle for all regions was 28 +/- 13 degrees . The mean angles in the region transitional between the IZ and AB and in the anterior region of the IZ were significantly greater than those in the posterior part of the IZ (p = 0.001 and 0.050 for the two comparisons). The large caliber, vertically oriented fibers in the AB, IZ and PB were counted in nine specimens. Disk dimensions were also measured in these specimens. The vertically and transversely oriented bundles were more frequent in the band regions. The number of vertically oriented fiber bundles varied within and between the disk bands. Vertical fiber number in the AB was greater laterally than medially (p = 0.04). In the PB the fiber number was greater than in either the AB or IZ (p = 0.000 for both comparisons) and within the PB itself the fiber number was greater in its thicker, medial half (p = 0.014). The fiber number in the AB and IZ was not different. The thickness of the AB, IZ and PB and disk length was measured in sections located laterally, centrally and medially. No difference in disk length was found across these planes. Statistically significant differences were found in regional disk thickness. In all of the mediolateral planes, the AB and PB were thicker than the IZ and the PB was thicker than the AB (p = 0.000 for all comparisons). The IZ was thicker medially than laterally (p = 0.034). The PB was thicker centrally and medially than laterally (p = 0.002 and 0.001, respectively). PB thickness in its central and medial regions was not different. The findings, combined with other evidence, suggest that the fiber system of the disk serves a stress distribution function and that within the AB and PB, the regions containing the greatest number of vertical fibers may also be the sites of greatest compressive stress during jaw function.