Tensile forces in the neurovascular bundle: A contributor to orthodontic relapse?

OBJECTIVES: The aim of this study is to investigate the neurovascular bundle (NVB) as a potential orthodontic relapse factor. The mechanical properties and the forces generated in the NVB after orthodontic extrusion are explored. MATERIALS AND METHODS: Six NVBs branching from the inferior alveolar nerve to the apices of the mandibular canines and premolars of mature pigs were harvested. Stress relaxation tests were conducted. A standard linear solid model (SLS) was utilized to simulate the orthodontic extrusion of a single rooted tooth with NVB length and cross-sectional diameter of 3.6 and 0.5 mm, respectively, so the NVB was stretched 10% and 20% of its original length. The maximum force within the NVB was then calculated. RESULTS: Based on our data, the average Young's modulus before relaxation ( E 0 ), after relaxation ( E P ) and the difference between Young's moduli before and after relaxation ( E S ) were 324 ± 123, 173 ± 73 and 151 ± 52 kPa, respectively. The theoretical force within the NVB stretched to 10% and 20% strain was 3 and 5 mN, respectively. CONCLUSION: The data from our study indicate that the NVB exhibits stress relaxation, a characteristic trait of viscoelastic materials. SLS model simulation predicted residual forces around 5 mN for elongation up to 20%. We observed strain hardening with additional elongation, which has the potential to cause forces to increase exponentially. Therefore, tensile forces in the NVB should not be ruled out as a contributor to orthodontic relapse, especially in adult patients who may have decreased adaptability of their NVB. Further preclinical and clinical models should be developed to further clarify what is the contribution of the NVB to orthodontic relapse.

Bias in the superimposition of lateral cephalograms in adult patients with anterior open bite.

INTRODUCTION: Anterior open bite malocclusion can be treated nonsurgically using fixed appliances, clear aligners, or temporary anchorage devices (TADs). Proponents of clear aligners and TADs often attribute bite closure to molar intrusion and counterclockwise rotation of the mandibular plane. These changes may be supported by superimpositions. However, the process of creating a superimposition is subjective and may be influenced by practitioner bias. METHODS: The initial and final lateral cephalograms from 30 adult anterior patients with open bite were used in this study. Ten patients were treated with fixed appliances, 10 with clear aligners, and 10 with TADs. We asked 6 orthodontic graduate students and 6 orthodontic practitioners to complete superimpositions using these radiographs in 3 separate sessions. In the first session, the raters were told that all patients only received treatment with fixed appliances. In the second session, the raters were told that all patients were treated with clear aligners only, and in the third session, they were told all patients were treated with fixed appliances and TADs. Superimpositions were performed using Dolphin software, and each superimposition was saved as a Portable Document Format image. Change in the mandibular plane was the primary outcome and was assessed categorically (closed, no change, opened). Cephalometric values were measured and used to investigate the dental and skeletal changes associated with treatment. RESULTS: Although the raters demonstrated a slight tendency toward the mandibular plane closing or staying the same when told the treatment was clear aligners or TADs, these differences were not statistically significant. A high degree of intrarater and interrater variability in the mandibular plane change was present in all 3 superimposition sessions. The measurements from the lateral cephs showed significant changes for overbite and incisor vertical and angular movements. Almost no change was observed in anterior facial height, mandibular plane angle, or vertical movement of the first molars. CONCLUSIONS: This study did not observe a significant amount of superimposition bias. However, there was considerable intrarater and interrater reliability. This suggests that the same initial and final cephs may be interpreted very differently on the basis of the subjective superimposition of the raters.

Torque recovery of the maxillary incisors with a modified double J retractor in a Class II division 2 case treated with clear aligners.

A patient with a Class II division 2 malocclusion is presented, illustrating the application of a modified double J retractor (DJR) and palatal miniscrews along with clear aligners to correct the malocclusion and normalize the incisor torque. In terms of incisor torque recovery, a nonextraction approach might be a good choice if the Class II correction could be successfully achieved with total arch distalization. When maxillary molar distalization was limited by anatomical boundaries, the treatment plan was changed to bilateral maxillary first premolar extractions, which led to even more retroclination of the maxillary incisors after space closure. Anterior interdental miniscrews were used to intrude the maxillary incisors. A modified DJR and palatal miniscrews were used to regain torque and achieve palatal root movement of the maxillary incisors. The treatment effects and biomechanical designs were evaluated for torque recovery of the retroclined maxillary incisors.

Torque control of maxillary anterior teeth with the double J retractor and palatal miniscrews during en masse retraction.

A double J retractor (DJR) and palatal miniscrews were used to retract maxillary anterior teeth after failure of buccal posterior miniscrews. The line of action passing through the center of resistance of the maxillary anterior teeth and the moment generated by the palatal miniscrews via torquing springs successfully controlled the overbite and incisor torque during space closure. The DJR and palatal miniscrews work well with labial fixed appliances to address bimaxillary protrusion.

En-masse retraction of maxillary anterior teeth with the Double J retractor and palatal miniscrews: A case report.

A double J retractor and palatal miniscrews were applied to retract maxillary anterior teeth without brackets after repeated periodontal flare-ups. The line of action passing through the center of resistance of maxillary anterior teeth and the moment generated by palatal miniscrews via torquing springs successfully controlled the overbite and incisor torque during space closure. In addition to en-masse retraction without brackets, it is also possible to combine this setup with labial fixed appliances or clear aligner treatment.

Anterior openbite malocclusion in adults.

OBJECTIVES: To investigate stability and satisfaction in adult anterior open bite (AOB) patients at least 9 months post-treatment, as well as patient and practitioner factors that may be associated with stability and satisfaction. MATERIALS AND METHODS: Practitioners and their adult AOB patients were recruited through the National Dental Practice-Based Research Network. Data on patient and practitioner characteristics, treatment recommendations and factors were previously collected. Treatment stability was determined by assessing post-treatment intraoral photographs. Patient satisfaction was determined from post-treatment questionnaires. Treatment was categorized into aligners, fixed appliances, temporary anchorage devices, and orthognathic surgery. Extractions were also investigated. Retention type was categorized into vacuum-formed, Hawley-style, or bonded retainers, and regimens were classified as full-time or part-time wear. RESULTS: Retention data collected from 112 patients had a mean post-treatment time of 1.21 years. There were no statistically significant differences in stability between treatment groups. Depending on whether a qualitative index or a millimetric measure was employed, stability ranged from 65% to 89%. Extractions and less initial lower incisor proclination were associated with higher stability in patients treated with fixed appliances only. High satisfaction was reported by patients at retention. There were no clear differences in stability or satisfaction among retention types or regimens. CONCLUSIONS: The stability of adult AOB orthodontic treatment was high, regardless of treatment or retainer modality. Satisfaction in adult AOB patients was high, regardless of retention type or regimen.

Outcomes used in trials regarding the prevention and treatment of orthodontically induced white spot lesions: A scoping review.

INTRODUCTION: The objective was to identify and summarize the outcomes and evaluation methods used in clinical trials regarding the prevention and treatment of orthodontically induced white spot lesions (WSLs). METHODS: Three electronic databases were searched to identify studies that were (1) clinical trials on prevention and/or treatment of orthodontically induced WSLs, (2) reported in English, and (3) published between January 2010 and October 2019. At least 2 authors assessed the eligibility and extracted the characteristics, outcomes, and evaluation methods from included studies. All disagreements were resolved through discussion. RESULTS: Among 1328 studies identified, 51 were eligible and included. A total of 48 different outcomes and 11 different evaluation methods were used in these studies. The most frequently used outcomes were WSLs clinical visual examination scores (n = 22, 43.1%), DIAGNOdent values (n = 14; 27.5%), fluorescence loss measured with quantitative light-induced fluorescence (QLF) (n = 10; 19.6%), and lesion area measured with QLF (n = 10; 19.6%). The most frequently used evaluation methods were clinical examination (n = 25; 49.0%), visual inspection by photographs (n = 15; 29.4%), DIAGNOdent (n = 14; 27.5%), and QLF (n = 10; 19.6%). None of the included studies reported data on quality of life. CONCLUSIONS: Substantial outcome heterogeneity exists among studies regarding the prevention and treatment of orthodontically induced WSLs. Most of the identified outcomes are aimed to assess morphologic changes of WSLs and may not reflect patient perspectives. REGISTRATION: The Core Outcome Set for trials on the prevention and treatment of enamel White Spot Lesions (COS-WSL) project was registered in the COMET Initiative database (No. 1399).

Retention: taking a more active role.

Retention may be particularly challenging after the correction of specific malocclusion features, such as tooth rotations, open bite and expansion, which are all inherently unstable. In this article, some indications for active retention are reviewed by highlighting a variety of clinical techniques and appliances. Active retention is discussed in relation to preservation of tooth alignment and in the three planes of space: sagittal, vertical and transverse. In some situations, an active retention regimen may be helpful to minimise or counteract relapse after orthodontic treatment and to improve patient satisfaction during the typically lengthy post-treatment period.

The National Dental Practice-Based Research Network Adult Anterior Open Bite Study: Patient satisfaction with treatment.

INTRODUCTION: This article evaluates and reports on the satisfaction of adult patients across the United States who received orthodontic treatment for anterior open bite malocclusion. The factors that influence satisfaction are also described. METHODS: Practitioners were recruited from the National Dental Practice-Based Research Network. On joining the Network, practitioner demographics and information on their practices were acquired. Practitioners enrolled their adult patients in active treatment for anterior open bite. Patient demographics, patient dentofacial characteristics, and details regarding previous and current treatment were collected through questionnaires at enrollment (T1). Pretreatment lateral cephalograms and intraoral frontal photographs were submitted. Treatment performed, and details related to treatment outcome were recorded through questionnaires at the end of active treatment (T2). Posttreatment lateral cephalograms and intraoral frontal photographs were submitted. Patient satisfaction at T2 was assessed using a 5-point Likert-type scale and open-ended responses. Predictive univariate models were developed to evaluate the factors that affect patient satisfaction. Open-ended responses were reviewed for general trends. RESULTS: T2 data were received for 260 patients, and 248 of these patients completed and returned the patient satisfaction questionnaires. High levels of satisfaction were found in this sample of adult patients receiving treatment for anterior open bite malocclusion. Specifically, 96% of the sample reported being very or somewhat satisfied. Only 10 patients (4%) were not satisfied with the treatment provided or an element of the final result. Successful open bite closure, treatment modality, and certain patient characteristics may affect patient satisfaction. However, there was insufficient power to demonstrate statistical significance because of the very low number of dissatisfied patients. Open-ended responses directly associated with patient satisfaction were received from 23 patients (9%). They relayed positive, neutral, and negative feelings about the treatment received and final results. Additional responses regarding the orthodontic treatment in general, but not specifically linked to patient satisfaction, were received from 119 patients (48%). These comments depict an overwhelmingly positive experience. CONCLUSIONS: Adult patients who received orthodontic treatment for anterior open bite malocclusion were generally satisfied with the treatment provided, as well as the final esthetic and functional results.

The National Dental Practice-Based Research Network Adult Anterior Open Bite Study: Treatment success.

INTRODUCTION: Anterior open bite (AOB) continues to be a challenging malocclusion for orthodontists to treat and retain long-term. There is no consensus on which treatment modality is most successful. This study reports on the overall success rate of AOB orthodontic treatment in the adult population across the United States, as well as 4 major treatment modalities and other factors that may influence treatment success. METHODS: Practitioners and their adult patients with AOB were recruited through the National Dental Practice-Based Research Network. Patient dentofacial and demographic characteristics, practitioner demographic and practice characteristics, and factors relating to orthodontic treatment were reported. Treatment success was determined from posttreatment (T2) lateral cephalometric films and intraoral frontal photographs. Treatment was categorized into 4 main groups: aligners, fixed appliances, temporary anchorage devices (TADs), and orthognathic surgery. Extractions were also evaluated. Bivariate and multivariable models were used to investigate the association between treatment success and treatment modality, pretreatment (T1) dentofacial characteristics, patient and practitioner demographics, and practice characteristics, adjusting for clustering of patients within practice. RESULTS: A total of 254 patients, enrolled by 84 practitioners, contributed to T2 data for this study. There were 29 patients in the aligner group, 152 in fixed appliances, 20 in TADs, and 53 in surgery. A total of 49 patients underwent extractions of teeth other than third molars. Ninety-three percent finished treatment with a positive overbite on the T2 lateral cephalogram, and 84% finished with a positive vertical overlap of all incisors. The small number of aligners and TAD patients limited the ability to compare success rates in these groups. Patients treated with orthognathic surgery had a higher rate of success compared with those treated with fixed appliances only. Treatment success was also associated with academic practice setting, T1 mandibular plane angle ≤30°, no to mild T1 crowding, and treatment duration <30 months. CONCLUSIONS: The overall success of orthodontic treatment in adult patients with AOB who participated in this study was very high. Orthognathic surgery was the only treatment modality that exhibited a statistically higher odds of successful outcomes. Some T1 dentofacial characteristics and treatment factors were associated with the successful closure of AOB.

The effect of digital diagnostic setups on orthodontic treatment planning.

INTRODUCTION: This study aimed to evaluate whether viewing digital treatment simulations influenced orthodontic treatment planning decisions or practitioners' confidence in their selected plans. METHODS: Records of 6 patients representing different case types (eg, missing teeth, crowding, sagittal discrepancies) were collected. A total of 22 orthodontists and 7 orthodontic residents viewed these records and formulated treatment plans for each case, indicating their most recommended plan and up to 2 alternative plans. After treatment planning each case, digital setups of each treatment plan indicated by the practitioner were shown. The practitioners were then asked if they still recommended their original plan, or if they would now recommend a different plan. Their confidence levels in the success of their plans were recorded before and after viewing the setups. RESULTS: After viewing the digital setups, there was a significant change in the treatment plan for 9.2% of the cases. These included modifications like changing the extraction pattern or proposing space closure rather than opening space for an implant. In an additional 14.4% of the cases, treatment plans underwent partial changes, like adding interproximal reduction or temporary anchorage devices. Practitioner confidence levels increased after viewing the setups. In cases where the treatment plan changed, the practitioner's confidence level in the plan increased the most, and the final confidence level was uniformly high among all practitioners. Practitioners reported the most helpful features of digital setups were the ability to superimpose the setup with the original model, determine the amount of tooth movement needed, check the final incisal relationship (overjet and overbite), and establish the amount of interproximal reduction required. CONCLUSIONS: Viewing digital setups resulted in changes to the treatment plans in about 24% of the cases. The use of digital setups was associated with higher levels of confidence in the selected plans.

The National Dental Practice-Based Research Network Adult Anterior Open Bite Study: Treatment recommendations and their association with patient and practitioner characteristics.

INTRODUCTION: This aim of this paper is to describe and identify the practitioner and patient characteristics that are associated with treatment recommendations for adult anterior open bite patients across the United States. METHODS: Practitioners and patients were recruited within the framework of the National Dental Practice-Based Research Network. Practitioners were asked about their demographic characteristics and their treatment recommendations for these patients. The practitioners also reported on their patients' dentofacial characteristics and provided initial cephalometric scans and intraoral photographs. Patients were asked about their demographic characteristics, previous orthodontic treatment, and goals for treatment. Four main treatment groups were evaluated: aligners, fixed appliances, temporary anchorage devices (TADs), and orthognathic surgery. Extractions were also investigated. Predictive multivariable models were created comparing various categories of treatment as well as extraction/nonextraction decisions. RESULTS: Ninety-one practitioners (mostly orthodontists) and 347 patients were recruited from October 2015 to December 2016. Increased aligner recommendations were associated with white and Asian patients, the presence of tongue habits, and female practitioners. TADs were recommended more often in academic settings. Recommendations for orthognathic surgery were associated with demographic factors, such as availability of insurance coverage and practitioner race/ethnicity, and dentofacial characteristics, such as anteroposterior discrepancies, more severe open bites, and steeper mandibular plane angles. Extraction recommendations were largely associated with severe crowding and incisor proclination. CONCLUSIONS: Both doctor and patient demographic factors, as well as dentofacial characteristics, were significantly associated with treatment recommendations for adult anterior open bite patients.

Agreement of treatment recommendations based on digital vs plaster dental models.

INTRODUCTION: The purpose of this study was to investigate differences in orthodontists' treatment plans based on digital models compared with plaster models. Additionally, we assessed whether digital or plaster models influence the reliability of orthodontists' treatment plans, as well as the amount of time required to arrive at the plan. METHODS: Sixteen orthodontists planned treatment for 20 patients at 2 time points using either the same or different model formats (digital or plaster). The treatment plan decisions and time spent making the plans were recorded. The permutation test and a random effects model were used to analyze the data. RESULTS: The treatment plans arrived at with digital and plaster models were similar. With respect to extractions, the mean difference between digital and plaster formats was 11.9% (95% CI, 7.5%-16.3%). For surgery, the mean difference was 9.4% (95% CI, 5.0%-13.8%). There was no significant difference in the agreement rate between those who viewed models in different formats compared with those who viewed models twice in the same format (P >0.05). The time spent to plan treatment with plaster models was not significantly different from the time spent with digital models (P = 0.87). CONCLUSIONS: Based on this study, digital models can be substituted for plaster models with no significant differences in the final plans, the reliability of the plans, and the time required to create the plan.

Effects of vibrational devices on orthodontic tooth movement: A systematic review.

INTRODUCTION: The aim of this systematic review was to investigate the ability of vibrational devices to increase the rate of orthodontic tooth movement or reduce pain associated with orthodontic treatment. METHODS: An electronic search for relevant randomized controlled trials (RCTs) was conducted using Medline via OVID (January 1, 1966, through March 30, 2018), and EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials until August 2017. Hand searching of selected orthodontic journals was also undertaken. RESULTS: Through the electronic searches, 152 titles and abstracts were identified. From these, 10 articles were retrieved for review, and 4 of these met the inclusion criteria. Two additional articles were identified by hand searching. This resulted in 6 studies from 5 separate randomized controlled trials that were included in this systematic review. One RCT reported increased tooth movement with vibrational devices, but the other 4 RCTs reported no difference. Three studies investigated the effect of vibrational devices on pain reduction and found no effect. CONCLUSIONS: The ability of vibrational forces to increase the rate of tooth movement and reduce pain in orthodontic patients has been studied in several RCTs. The results from all but 1 of the included studies indicate no advantage from the use of vibrational devices during orthodontic treatment. Future studies should focus on total treatment duration, the mechanism by which vibration may speed up tooth movement, and the use of vibration with aligners. FUNDING: No funding was received for this review.

The National Dental Practice-Based Research Network adult anterior open bite study: A description of the practitioners and patients.

OBJECTIVES:: To describe the demographic and practice characteristics of the clinicians enrolled in a large, prospective cohort study examining recommendations and treatment for adult anterior open bite (AOB) and the relationship between these characteristics and practitioners' self-reported treatment preferences. The characteristics of the AOB patients recruited were also described. MATERIALS AND METHODS:: Practitioners were recruited from the National Dental Practice-Based Research Network. Participants in the study consisted of practitioners and their adult AOB patients in active treatment. Upon enrollment, practitioners completed questionnaires enquiring about demographics, treatment preferences for adult AOB patients, and treatment recommendations for each patient. Patients completed questionnaires on demographics and factors related to treatment. RESULTS:: Ninety-one practitioners and 347 patients were recruited. Demographic characteristics of recruited orthodontists were similar to those of American Association of Orthodontists members. The great majority of practitioners reported using fixed appliances and elastics frequently for adult AOB patients. Only a third of practitioners reported using aligners frequently for adult AOB patients, and 10% to 13% frequently recommended temporary anchorage devices (TADs) or orthognathic surgery. Seventy-four percent of the patients were female, and the mean age was 31.4 years. The mean pretreatment overbite was -2.4 mm, and the mean mandibular plane angle was 38.8°. Almost 40% of patients had undergone orthodontic treatment previously. CONCLUSIONS:: This article presents the demographic data for 91 doctors and 347 adult AOB patients, as well as the practitioners' self-reported treatment preferences.