Characterizing orthodontic tooth movement in real time using dental monitoring scans: A pilot study.

OBJECTIVES: This pilot study aimed to quantify the magnitude and type of tooth movement occurring in short time intervals within the regular monthly orthodontic visits for patients with fixed appliances and undergoing maxillary canine retraction. Additionally, this pilot study aimed to provide a descriptive evaluation for the accuracy and reliability of the Dental Monitoring (DM)-captured scans to those of an iTero digital scans in an extraction space closure model. SETTINGS AND SAMPLE POPULATION: 3D intraoral photographic scans (DM) for 12 patients with maxillary first premolar extractions in a single-centre academic institution. MATERIALS AND METHODS: Twelve patients treated with fixed appliances and undergoing space closure for maxillary premolar extraction(s) were included. Nickel-titanium (200 g) closing coil springs were used for canine retraction. At initiation of space closure (T1), iTero scans were acquired, and patients were instructed to take DM scans every 4-5 days until their next visit in 4-5 weeks (T2). At T2, a final iTero scan in addition to a DM scan was taken. The number of patients who did the scans regularly as instructed declined as time elapsed. Stereolithography (STL) files generated from the DM scans were superimposed with the STL files from the iTero scans using GOM Inspect software to determine the accuracy of the DM 3D models. To assess rate, type and direction of tooth movement, each of the 3D image STL files generated from the DM scans, taken every 4-5 days by each patient, was superimposed on the previously captured scan. The rate of tooth movement for the maxillary molars and canines was calculated in the 3 planes of space (X, Y, Z) at each time point, until the end of the experiment. RESULTS: Preliminary results indicated that the maxillary canines appeared to be displaced the greatest amount in the first 4-5 days with initial distolateral movement. As time elapsed, the rate of tooth movement decreased, and the tooth started moving distolingually. CONCLUSIONS: Dental monitoring software provides a high-tech platform to monitor tooth movement in a 'real-time' approach. Accuracy of the photographic scans in relationship to the intraoral scans appears promising. There seems to be some evidence that the greatest amount of movement occurs initially in the first few days after activation, dropping thereafter to become a slower constant rate of tooth movement.

Assessment of the occlusal outcomes in patients treated with orthognathic surgery and clear aligners.

OBJECTIVE: This retrospective two-centre study aimed to evaluate the occlusal outcomes in patients undergoing orthognathic surgery with clear aligners. METHODS: A retrospective chart review and occlusal outcomes for 15 patients (10 females and five males) with different types of dentofacial deformities in the anteroposterior, vertical and transverse dimensions, who underwent orthognathic surgery in conjunction with clear aligners were evaluated. Weighed Peer Assessment Rating (PAR) index scores of the pre-treatment and post-treatment digital models were used to assess initial complexity, final occlusal outcomes and degree of improvement with surgery and clear aligners. RESULTS: The mean post-treatment PAR score was 3.5 ± 2.54, which was a statistically significant improvement from the pre-treatment PAR score of 27.63 ± 12.09, an 87% improvement was achieved. All subcategories of the PAR index showed statistically significant improvement except for midline assessment component. CONCLUSIONS: Occlusal outcomes with aligners showed great improvement as indicated with the PAR index scores. Orthognathic surgical cases can be treated efficiently with aligners and future studies should compare occlusal outcomes between orthognathic surgical patients treated with clear aligners and those treated with fixed appliances.

Survival and failure rate of lower lingual bonded retainers: A retrospective cohort evaluation.

OBJECTIVE: The objectives of the study were to evaluate the survival rates for lower lingual retainers (LLRs) and to establish a correlation between patients' treatment-related factors (age, sex, malocclusion, appliance used for treatment, teeth bonded, retention protocols) to the survival of LLRs. MATERIALS AND METHODS: A total of 765 subjects [474 females and 291 males: mean age = 24.29 ± 10.67 years] between 2013 and 2022 were included. A customized data collection form was utilized to gather the data from the electronic health record (EHR) of subjects. Patient-related factors, crowding or spacing, deep bite or open bite and duration of treatment were extracted from patients' files. Kaplan-Meier estimator was used for the survival function, whereas Cox proportional hazards regression models were used to associate risk factors with retainer survival. RESULTS: 328 (42.9%) subjects had their LLRs failed, and the survival period was on average 17.37 ± 22.85 months. On the other hand, the follow-up period for the retainers that did not fail was on average 47.19 ± 23.66 months. 192 (28.3%) subjects had segment failure (retainer detached from 3 teeth or less), while 51 (7.5%) subjects had failures in more than 3 teeth (complete). None of the evaluated clinical variables were significantly associated with LLRs failure except for the bite category (P = .013) and the appliance used for treatment (P < .001). CONCLUSION: Success rate for LLRs was 57.1% over 47.19 months, failure rate was 42.9% over 17.37 months. The presence of deep bite and treatment with aligners were significantly associated with increased failure rate.

Dental implant and bone augmentation treatment in bone-compromised patients: Oral health-related quality of life outcomes.

STATEMENT OF PROBLEM: Patient-reported outcomes represent an additional and often overlooked measure of dental implant and bone augmentation treatment. Few implant studies have evaluated patient-reported outcomes in those with systemic bone compromise. PURPOSE: The purpose of this cohort study was to assess oral health-related quality of life (OHRQoL) outcomes in postmenopausal women receiving dental implants with normal bone density or mild osteopenia ("healthy" group; all DXA T-scores at femoral neck, total hip, and L1-L4 spine>-2.0) versus moderate osteopenia or osteoporosis ("bone compromised" group; any DXA T-score at femoral neck, total hip, or L1-L4 spine≤-2.0). MATERIAL AND METHODS: A total of 115 patients were recruited at the University of Connecticut School of Dental Medicine as part of a standard of care, prospective, nonrandomized cohort study. All participants received 1 of 3 bone augmentation procedures with implant placement. At baseline and at various intervals after implant placement, OHRQoL was measured by using the Oral Health Impact Profile-14 (OHIP-14) and surveys of patient expectations and satisfaction. These measures were compared between healthy and bone compromised groups (α=.05). RESULTS: For all OHRQoL measures across linear mixed effects models, no significant differences were found between bone groups at baseline and at each time point after implant placement (P>.05). Using the minimally important difference (MID) for OHIP-14, no definitive clinical differences were found in patient outcomes between bone groups at all postimplant time points (P>.05). From baseline to 24 months after implant placement, both healthy and bone compromised groups exhibited significant improvements in OHIP-14 and patient expectations scores (P<.05). While no within group differences were found in patient satisfaction scores, the mean satisfaction score remained high over time in both groups. CONCLUSIONS: Patient-reported outcomes as measured through OHIP-14, patient expectations, and patient satisfaction surveys suggest similar postimplant OHRQoL improvement in healthy and bone compromised individuals. OHRQoL improvements between bone groups were similar both in continuity and in scope, with no evidence of statistically significant score differences between groups at 24 months after implant placement across all measures and with no definitive evidence of clinical differences as measured by OHIP-14 MID comparisons across all timepoints.

Assessment of clear aligner accuracy of 2 clear aligners systems.

INTRODUCTION: This study compared treatment efficacy for specific tooth movements between 2 clear aligner systems (Clarity [3M Oral Care Solutions, St Paul, Minn] and Invisalign [Align Technology, San Jose, Calif]). METHODS: The study sample included 47 patients (7 males, 40 females; mean age, 36.57 ± 15.97 years) treated with Invisalign and 37 (4 males, 33 females; mean age, 34.30 ± 16.35 years) treated with Clarity aligners who completed their first set of aligners and had an initial refinement scan. Initial and predicted models were obtained from the initial simulated treatment plan. The first model of the refinement scan was labeled as achieved. SlicerCMF software (version 3.1; http://www.slicer.org) was used to superimpose the achieved and predicted digital models over the initial ones with regional superimposition on the relatively stable first molars. Nine hundred forty teeth in the Invisalign system were measured for horizontal, vertical, and angular movements and transverse width and compared with similar measurements of 740 teeth for the Clarity aligners. The deviation from the predicted was calculated and compared between both systems. RESULTS: The deviation achieved from the predicted was significant between the groups for the mandibular interpremolar and intercanine widths (P <0.05). Clarity aligners significantly undercorrected rotations compared with Invisalign for the mandibular first premolars, mandibular canines, maxillary canines, and maxillary central incisors. There was no statistically significant difference between the groups for the achieved vs predicted movements in the horizontal and vertical planes (P >0.05). CONCLUSIONS: The efficacy of clear aligner therapy systems (Clarity and Invisalign) in treating mild and moderate malocclusions was comparable. Deviation of the achieved movements from the predicted was greatest for rotational and vertical movements.

Comparison of electronic versus mechanical torque-limiting devices for dental implants: An in vitro study.

PURPOSE: To determine the accuracy of new electronic torque-limiting devices (ET) when compared to new and used conventional-style beam-type (BT) mechanical torque-limiting devices and hand-piece style (HS) mechanical torque-limiting devices. The secondary purpose was to compare any difference in accuracy between new and used mechanical torque-limiting devices, and any difference in accuracy when used on a straight versus an angled screw channel abutment. MATERIALS AND METHODS: A total of five torque-limiting devices were used to obtain 2000 readings under standardized conditions. An implant analog was fastened into a digital torque meter, to which an abutment was connected. Pre-determined torque values of 15 Ncm and 35 Ncm were applied, and actual torque values were recorded. A straight and an angled abutment were used to record 1000 readings each using the five torque-limiting devices. An overall Kruskal-Wallis test was applied to compare the median deviation among devices followed by a pairwise comparison ( = 0.05). RESULTS: For a target torque value of 15 Ncm on a straight abutment, the electronic device (ET) was statistically more accurate than the beam type (BT) new (p < 0.001) and used (p < 0.048) devices but less accurate than the hand-piece style (HS) used device (p < 0.001). On an angled abutment for a target value of 15 Ncm, the electronic device (ET) was statistically more accurate than hand-piece style (HS) new and used devices (p < 0.001). For a target torque value of 35 Ncm on a straight abutment, the ET was statistically more accurate than the HS new device (p < 0.001) but less accurate than the BT new device (p < 0.001). On an angled abutment for a target value of 35 Ncm, the electronic device (ET) was statistically less accurate than the beam-type (BT) new device (p < 0.001), the beam-type (BT) used device (p = 0.001), and the hand-piece style (HS) used device (p < 0.001). The electronic device (ET) was the only device accurate within the ISO standard of accuracy of 6% for each of the target torque value/abutment design combinations. There was no statistically significant difference related to the type of abutment used (angled vs. straight). CONCLUSIONS: Electronic torque limiting devices (ET) are an acceptable method for delivering torque for implant restorations for straight and angled abutments at 15 Ncm and 35 Ncm torque values. Conventional style beam-type (BT) mechanical torque-limiting devices are a simple, predictable, validated, and inexpensive tool for delivering accurate torque at 15 Ncm and 35 Ncm torque values. The hand-piece style (HS) mechanical torque-limiting devices are predictable to deliver 15 Ncm torque values.

Comparable Skeletal and Dental Movements Achieved Using Conventional and Surgery-First Techniques in Class III Patients.

PURPOSE: The surgery-first (SF) approach to orthognathic surgery has been proposed as a more efficient method to correct the dentofacial deformity. This study aimed to evaluate if the magnitude of skeletal and dental changes achieved in Class III patients treated with either conventional orthognathic surgery (COS) or SF techniques differ. METHODS: A retrospective cohort study of Class III orthognathic surgery patients between January 2006 and May 2020 with available pre- and post-treatment lateral cephalograms was conducted at an academic institution. The primary predictor variable was surgery technique: COS or SF. Assessed outcome variables included cephalometric skeletal parameters: SNA, SNB, ANB, Wits Appraisal, Sn-GoGn, and FMA; and dental parameters: U1-SN, U1-NA (°), U1-NA (mm), L1-NB (°), L1-NB (mm), and overjet. Within-group posttreatment parameters were analyzed with paired t tests. Pretreatment, posttreatment, and between-group parameter changes were analyzed by 2-sided 2-sample independent t tests. Potential covariates, including gender, surgical procedure, previous conventional treatment, extractions (excluding 3rd molars), crowding, and midline discrepancy, were analyzed using Fisher exact tests. RESULTS: Thirty-nine subjects were included in this study: 1) 21 COS (age: 20.9 ± 8.7 years) and 2) 18 SF (age: 19.6 ± 5.0 years). Cohorts were comparable (P > .05) for all analyzed covariates. COS showed statistically significant increases in L1-GoGn (3.31 ± 6.23°; P = .024), overjet (4.26 ± 3.99 mm; P < .001), ANB (3.5 ± 2.79°; P < .001), SNA (3.5 ± 1.85°; P < .001), and Wits Appraisal (3.78 ± 4.97 mm; P = .002). SF showed statistically significant increases in L1-GoGn (4.19 ± 4.85°; P = .002), L1-NB (3.08 ± 4.13°; P = .006), L1-NB (0.79 ± 1.35 mm; P = .023), overjet (5.82 ± 2.96 mm; P < .001), ANB (5.51 ± 3°; P < .001), SNA (4.13 ± 2.38°; P < .001), and Wits Appraisal (5.92 ± 3.42 mm; P < .001) and statistically significant decreases in U1-NA (-3.69 ± 7.35°; P = .048) and SNB (-1.38 ± 2.14°; P = .014). There were no statistically significant differences in skeletal or dental parameters between groups when adjusted for pretreatment levels of that parameter. The mean treatment duration was 38 months (standard deviation = 12.7) in COS and 17.6 months (standard deviation = 5.2) in SF. CONCLUSIONS: The results show that skeletal and dental changes between groups were not statistically different, despite an average 20-month difference in treatment duration. This suggests that either technique can be used to achieve comparable degrees of skeletal and dental movement in Class III patients.

Long-term effects of conventional and miniscrew-assisted rapid palatal expansion on root resorption.

INTRODUCTION: The purpose of this study was to use cone-beam computed tomography to compare immediate and long-term effects of conventional and miniscrew-assisted rapid palatal expansion (MARPE) appliances on root resorption in 2 treatment groups and a control group. METHODS: One hundred eighty cone-beam computed tomography images of 60 patients at 3 time points were assessed: initial, postexpansion, and debond. The patients were divided into 3 groups: control (n = 19), rapid palatal expansion (RPE) appliance (n = 21), and MARPE (n = 20). The period of initial to debond varied for the 3 groups: 2 years, 7 months for controls; 2 years, 9 months for RPE; and 2 years, 8 months for MARPE. The length of mesiobuccal, distobuccal, and palatal root of the maxillary first molar (1M); the buccal root of maxillary first premolar; and second premolar were measured. The inclination of the 1M, intercuspal width (ICW), interroot width (IRW), ICW/IRW ratio, maxillary skeletal width were measured in all 3 groups at different time points. RESULTS: Immediately after expansion, RPE and MARPE groups showed a significant increase in the molar inclination, ICW, ICW/IRW ratio, and maxillary skeletal width compared with controls at postexpansion. However, the long-term comparison did not show any significant difference for root resorption and expansion parameters between the 3 groups, except the ICW/IRW ratio, which was higher in MARPE than controls at debond. A significant negative association was observed between the length of the mesiobuccal root of 1M and molar inclination (ß = -0.025; 95% confidence interval, -0.050 to 0.0008; P <0.05). The expansion of ICW and IRW did not show a significant association with root resorption. CONCLUSIONS: The long-term outcomes showed no difference in the amount of root resorption between the RPE, MARPE, and control groups. Molar inclination showed a significant negative association with the length of the mesiobuccal root of the 1M.

Association between initial complexity, frequency of refinements, treatment duration, and outcome in Invisalign orthodontic treatment.

INTRODUCTION: This study explored possible associations between treatment duration, initial complexity, outcomes in Invisalign therapy, and the number of refinements. METHODS: Three-dimensional models (initial, final, and refinements) of 355 Invisalign patients (114 males and 241 females; 33.8 ± 17.1 years) were analyzed using the Peer Assessment Rating (PAR) index questionnaire tool in the Ortho Analyzer software (version 2.0; 3Shape, Copenhagen, Denmark) to calculate the weighted total and individual PAR index scores for each component of the PAR index. Data related to demographics, treatment duration, and the number of refinements were collected. RESULTS: Treatment duration increased as the number of refinements increased. Percent of improvement was higher in PAR ≥22 group than PAR <22 with an increase in the number of refinements: 83.3% vs 73.8% for 2 refinements; 94.7% vs 91.2% for 3 refinements; and 100% vs 85.7% for ≥4 refinements. Those who achieved great improvement or improvement and those who did not were significantly different in treatment duration (P <0.001 and P = 0.027), number of refinements (≥3 refinements; P <0.001), initial occlusal severity (PAR ≥22; P <0.01 and P = 0.031). Most subjects achieved improvement after the first refinement (64.5% for PAR <22 and 78.5% for PAR ≥22). Few had ≥4 refinements, and if they did, none achieved improvement with additional refinements. CONCLUSIONS: Initial complexity for an Invisalign case is associated with treatment duration, achieved outcomes, and the number of refinements. Treatment duration increased with an increased number of refinements. Great improvement or improvement for the first time dropped to 0 if additional refinements were carried out after 3. Therefore, performing additional refinements does not necessarily mean better occlusal outcomes.

Biodegradable Piezoelectric Force Sensor.

Measuring vital physiological pressures is important for monitoring health status, preventing the buildup of dangerous internal forces in impaired organs, and enabling novel approaches of using mechanical stimulation for tissue regeneration. Pressure sensors are often required to be implanted and directly integrated with native soft biological systems. Therefore, the devices should be flexible and at the same time biodegradable to avoid invasive removal surgery that can damage directly interfaced tissues. Despite recent achievements in degradable electronic devices, there is still a tremendous need to develop a force sensor which only relies on safe medical materials and requires no complex fabrication process to provide accurate information on important biophysiological forces. Here, we present a strategy for material processing, electromechanical analysis, device fabrication, and assessment of a piezoelectric Poly-l-lactide (PLLA) polymer to create a biodegradable, biocompatible piezoelectric force sensor, which only employs medical materials used commonly in Food and Drug Administration-approved implants, for the monitoring of biological forces. We show the sensor can precisely measure pressures in a wide range of 0-18 kPa and sustain a reliable performance for a period of 4 d in an aqueous environment. We also demonstrate this PLLA piezoelectric sensor can be implanted inside the abdominal cavity of a mouse to monitor the pressure of diaphragmatic contraction. This piezoelectric sensor offers an appealing alternative to present biodegradable electronic devices for the monitoring of intraorgan pressures. The sensor can be integrated with tissues and organs, forming self-sensing bionic systems to enable many exciting applications in regenerative medicine, drug delivery, and medical devices.

Comparison of external apical root resorption with clear aligners and pre-adjusted edgewise appliances in non-extraction cases: a systematic review and meta-analysis.

OBJECTIVE: The aim of this study was to evaluate and compare the amount of external apical root resorption (EARR) observed during the orthodontic treatment with pre-adjusted edgewise appliance (PEA) or clear aligner therapy (CAT) and with 2D or 3D radiographic methods of measuring the root resorption. SEARCH STRATEGY AND SELECTION CRITERIA: A search of PubMed MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, LILACS, Web of Science, Dissertations & Theses Global, ClinicalTrials.gov registry, and the ISRCTN Registry was performed. Studies that have evaluated the amount of root resorption in non-extraction cases using CAT or PEA were selected for the systematic review. A meta-analysis was performed for the amount of root resorption of permanent maxillary incisors using PEA or CAT treatment modalities by either 2D or cone-beam computed tomography radiographic examination. DATA COLLECTION AND ANALYSIS: Database research, elimination of duplicate studies, data extraction, and risk of bias were performed by authors independently and in duplication. A random-effect meta-analysis followed by subgroup comparisons were performed to evaluate EARR. RESULTS: A total of 16 studies (4 were prospective and 12 were retrospective) were identified for inclusion in the systematic review. The mean root resorption for the permanent maxillary incisors was in the range from 0.25 to 1.13 mm (overall: 0.49 mm; 95% confidence interval [CI] = 0.24 to 0.75 mm). The mean root resorption difference between CAT and PEA was statistically significant (P < 0.05) for 12 but not for 21, 11, or 22. LIMITATIONS: One of the drawbacks is a lack of good quality prospective studies, specifically randomized clinical trials in the literature. CONCLUSIONS AND IMPLICATIONS: Neither PEA or CAT technique leads to clinically significant root resorption (1 mm) of the maxillary incisors. The amount of EARR of maxillary incisors is not significant in comparing two treatment modalities (PEA and CAT), except for 12, where the PEA group has significantly more EARR when compared to CAT. REGISTRATION: The protocol for this systematic review was based on the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 and was registered at PROSPERO database (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018113051). This systematic review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

The Influence of Age and Facial Expression (Eye Open/Closed) On Maxillary Dental and Gingival Display.

PURPOSE: To assess if there are any differences in maxillary dentogingival exposure between different facial expressions (maximum smile with eyes open and eyes closed), age groups and both sexes. MATERIAL AND METHODS: Digital photographs of the lower third of the face of 120 subjects, belonging to 6 different age groups were taken. There were 20 subjects in each of the 6 age groups (20-30, 30-40, 40-50, 50-60, 60-70, and 70-80) which were comprised of 80 women and 40 men. Two standardized images of each subject were taken, one of maximum smile with eyes open, and the second of maximum smile with eyes closed. These 240 images were used to quantify a dentogingival exposure ratio (DER) for each tooth spanning the second bicuspids on either side, using standardized measurement techniques. Additionally, incidence of interdental papilla visibility was studied in a binary manner, and all data were studied with respect to various covariables of age, sex and type of facial expression using a generalized linear mixed effects model. A p-value < 0.05 was determined to be statistically significant. RESULTS: There was a statistically significant difference between the dentogingival exposure ratio (DER) for all images with eyes open and eyes closed per tooth location studied, across all age groups (p ≤ 0.001) and both sexes, suggesting that subject images of smiles with eyes closed had significantly higher dentogingival exposure. There was a decreasing trend of DER with increasing age groups when eyes were open (p = 0.005) and when eyes were closed (p = 0.042), suggesting that older subjects had lower dentogingival exposure. With respect to sex, there was no statistically significant difference in mean DER between males and females, when eyes were open (p = 0.430) and closed (p = 0.351). The incidence of interdental papilla exposure also differed significantly between images with eyes open and eyes closed across all age groups (p ≤ 0.001). However, the incidence of interdental papilla exposure decreased with age, only in images with eyes open (p < 0.001) but was not statistically significant among images with eyes closed (p = 0.127). With respect to sex, there was a significant difference in incidence of interdental papilla exposure in images with eyes open (p = 0.029) but no significant difference when eyes were closed (p = 0.782). CONCLUSIONS: Maxillary dentogingival exposure decreases with increasing age and is significantly higher when recording maximum smile with eyes closed, for all age groups and both sexes. As this is a simple and clinically reproducible facial expression, incorporating patient's maximum smiling images with eyes closed may be routinely necessary for complete and accurate data collection for prosthodontic treatment planning purposes.

An analysis of anterior mandibular anatomy by using cone beam computed tomography: A study of 225 mandibular images.

STATEMENT OF PROBLEM: The anterior mandible has conventionally been deemed as a safe zone for dental implants. However, with the evolution of cone beam computed tomography (CBCT), several anatomic challenges have been identified that, if violated, can lead to surgical complications, including life-threatening hemorrhage. PURPOSE: The purpose of this observational clinical study was to obtain standardized average values for the location of the sublingual artery (SLA), submental artery (SMA), and mandibular incisive canal (MIC) and to determine whether differences exist between dentate and edentulous individuals. In addition, the prevalence of these anatomic landmarks on CBCT images was determined. An additional objective was to study the cross-sectional morphology of the anterior mandible. MATERIAL AND METHODS: CBCT images of 125 edentulous and 100 dentate patients were studied at the anterior mandible for the prevalence of SLA, SMA, and MIC. Measurements of these 3 structures were then made from the inferior cortical border of the mandible to the superior border of each structure to obtain average anatomic measurements. The cross-sectional shapes of anterior mandibles were then categorized, and the prevalence of each shape in this sample was calculated. RESULTS: The prevalence of SLA across all 225 CBCT images was 100% for edentulous patients and 98% for dentate patients. The SLA was located approximately 15 mm above the inferior border of the mandible. The prevalence of SMA was 94% for edentulous patients and 88% for dentate patients. The SMA was located approximately 5 mm above the inferior border of the mandible. The prevalence of MIC was 61% for edentulous patients and 59% for dentate patients. The MIC was located approximately 11 mm above the inferior border of the mandible in edentulous patients and approximately 14 mm above the inferior border of the mandible in dentate patients. Five distinct shapes were observed for the cross-sectional morphology of the anterior mandible: hourglass (1%), pear (53%), sickle (4%), ovoid (26%), and triangular (17%). The distance from the crest of the residual ridge to a minimum 6-mm width in the anterior mandible was approximately 4 mm. CONCLUSIONS: The SLA and SMA vascular structures were consistently identified in the anterior mandible on CBCT images, both in dentate and edentulous patients, whereas the mandibular incisive canal was not consistently visualized. Average values from the inferior border of the mandible to the SLA, SMA, and MIC were computable. The cross-sectional morphology of the anterior mandible is diverse in dentate and edentulous mandibles, with pear shaped being the most common in both. These findings should be taken into consideration when dental implants are planned in the anterior mandible.

Influence of type of radiograph and levels of experience and training on reproducibility of the cervical vertebral maturation method.

INTRODUCTION: The objective of this study was to assess the reproducibility of cervical vertebral maturation (CVM) method based on the type of radiographic image and the level of experience and level of training of the evaluator. METHODS: Ten evaluators (5 orthodontic residents and 5 faculty members) were randomly divided into 2 groups: trained and untrained. All participants evaluated 80 radiographic images previously acquired in 4 different formats: (1) 2-dimensional (2D) digital (2D-digital), (2) 2D digitized hard copy from the Iowa Facial Growth Study (American Association of Orthodontists Foundation Craniofacial Growth Legacy Collection), (3) 2D digital reconstructed from a 3-dimensional (3D) radiograph (2D-from 3D), and (4) 3D cone-beam computerized tomographic (3D-CBCT) images. Agreement among evaluators on the morphology of the cervical vertebrae (CV) and the CVM stage of each radiographic image was assessed using Randolph's kappa statistic and Kendall's W coefficient of concordance. RESULTS: Interobserver agreement on the determination of a curvature on the inferior border of the CV was substantial to perfect, whereas agreement on shape was fair to moderate. Overall, the level training in all image types, except 3D-CBCTs, but not the level of experience affected the agreement for shape and curvature of the CVs. Interobserver agreement on CVM staging for all combined images was substantial at 0.72. Faculty had a higher level of agreement than residents except for 2D-digital and 3D-CBCT images, whereas trained evaluators had an overall higher level of agreement than untrained evaluators except for 3D-CBCT images. CONCLUSIONS: Interobserver agreement in determining CVM stage was substantial for all images evaluated; experience and training resulted in higher level of agreement for some image types. The 3D-CBCT images did not provide increased interobserver agreement over current 2D-digital lateral cephalograms in determining CVM staging or shape of the CV. The highest agreement in CVM staging was obtained on 2D-digital lateral cephalograms with training.

Biomarkers of orthodontic tooth movement with fixed appliances and vibration appliance therapy: a pilot study.

INTRODUCTION: The aim of this study was to investigate the effect of supplemental vibratory force on biomarkers of bone remodelling during orthodontic tooth movement, the rate of mandibular anterior alignment (RMAA), and compliance with a vibration device. DESIGN, SETTINGS, AND PARTICIPANTS: Forty patients between the ages 15-35 undergoing fixed appliance treatment that presented to a university orthodontic clinic were randomly allocated to supplemental use of an intraoral vibrational device (n = 20, AcceleDent®) or fixed appliance only (n = 20). Salivary multiplex assay was completed to analyse the concentration of selected biomarkers of bone remodelling before treatment (T0) and at three following time points (T1, T2, T3), 4-6 weeks apart. Irregularity of the mandibular anterior teeth and compliance was assessed at the same trial time points. Data were analysed blindly on an intention-to-treat basis with descriptive statistics, Mann-Whitney U-test, Wilcoxon signed-rank test, and linear mixed effects regression modelling. RESULTS: No difference in the changes in salivary biomarkers of bone remodelling and RMAA between groups at any time point over the trial duration was observed. No correlation was found between changes in irregularity and biomarker level from baseline to another time point. Lastly, there was no association between RMAA and compliance with the AcceleDent® device. CONCLUSIONS: Supplemental vibratory force during orthodontic treatment with fixed appliances does not affect biomarkers of bone remodelling or the RMAA. LIMITATIONS: The main limitation of the study was the small sample size and the large variability in the salivary biomarkers. HARMS: No harms were observed during the duration of the trial. PROTOCOL: The protocol was not published prior to trial commencement. REGISTRATION: The study was registered in Clinical Trials.gov (NCT02119455) first posted on April 2014.

Relationship between Radiographic Misfit and Clinical Outcomes in Immediately Loaded Complete-Arch Fixed Implant-Supported Prostheses in Edentulous Patients.

PURPOSE: To examine if an uncorrected radiographically detected immediate postoperative misfit (implant level or abutment level) in immediately loaded conversion prosthesis plays a significant role in early implant or prosthesis failure. In addition, clinical characteristics related to type of arch, implant position, type of implant, implant orientation, type of connection, and type of surgery were analyzed relative to their relationship to early implant or prosthesis failure. MATERIALS AND METHODS: Immediate postoperative and subsequent follow-up panoramic radiographs of 425 arches with immediately loaded complete-arch fixed implant-supported prostheses were screened in a retrospective analysis. Implants with misfit and nonmisfit within a given arch were summarized separately with respect to each clinical characteristic and the difference between misfit and nonmisfit groups was tested using a mixed-effects logistic regression model with a patient-specific random intercept. A p-value <0.05 was determined to be statistically significant. RESULTS: A total of 2025 implants from 311 patients were identified in the 425 arches that were screened for radiographic misfit. A total of 48 implants with misfit were found within 33 arches (23 patients) for a 2.4% prevalence rate. Among the misfit implants, two failures were documented during the healing phase for an early implant survival rate of 95.8%. Five conversion prostheses with misfit fractured during the healing phase for early prosthesis survival rate of 84.8%. None of the clinical variables analyzed were significantly associated with the misfit status (p < 0.05). CONCLUSIONS: The results from this retrospective study showed that misfit in immediately loaded complete-arch fixed implant-supported prostheses may not play a detrimental role in the implant survival but may affect survival of the conversion prostheses.

Which orthodontic appliance is best for oral hygiene? A randomized clinical trial.

INTRODUCTION: Clear aligners and to a lesser extent self-ligated brackets are considered to facilitate better oral hygiene than traditional fixed orthodontic appliances. This 3-arm parallel-group prospective randomized clinical trial compared the long-term and short-term effects of clear aligners, self-ligated brackets, and conventional (elastomeric-ligated) brackets on patients' oral hygiene during active orthodontic treatment. METHODS: Seventy-one participants (41 boys, 30 girls; mean age, 15.6 years) undergoing orthodontic treatment were randomly allocated through a computer-generated randomization schedule to one of the groups based on the choice of intervention: Clear Aligners (CLA) (Align Technology, San Jose, Calif) (n = 27), preadjusted edgewise fixed appliance with self-ligated brackets (SLB) (Carriere, Carlsbad, Calif (n = 22), or preadjusted edgewise fixed appliance with elastomeric ligated brackets (ELB) (Ortho Organizers Inc., Carlsbad, CA) (n = 22). For each participant, the primary outcome, plaque index (PI), and secondary outcomes, gingival Index (GI) and periodontal bleeding index (PBI), were measured at baseline (T0), after 9 months of treatment (T1), and after 18 months of treatment (T2). Blinding of the clinicians and the patients to the intervention was impossible. It was only done for outcome assessment and for the statistician. Ten participants did not receive the allocated intervention for various reasons. RESULTS: The means and standard deviations of PI at T0 (CLA, 0.50 ± 0.51; SLB, 0.65 ± 0.49; ELB, 0.70 ± 0.73), T1 (CLA, 0.83 ± 0.48; SLB, 1.38 ± 0.72; ELB, 1.32 ± 0.67), and T2 (CLA, 0.92 ± 0.58; SLB, 1.07 ± 0.59; ELB, 1.32 ± 0.67) were similar. The odds ratio (OR) for plaque index (0 or ≥1) comparing SLB or CLA to ELB was not significant. OR for SLB vs ELB = 1.54 at T0 (95% CI, 0.39-6.27), 0.88 at T1 (95% CI, 0.03-24.69), and 0.83 at T2 (95% CI, 0.02-27.70); OR for CLA vs ELB = 1.07 at T0 (95% CI, 0.30-3.88), 0.24 at T1 (95% CI, 0.01-1.98), and 0.17 at T2 (95% CI, 0.01-1.71). However, the odds ratios comparing CLA with ELB for GI (OR = 0.14; P = 0.015) and PBI (OR = 0.10; P = 0.012) were statistically significant at T1. CONCLUSIONS: In this prospective randomized clinical trial, we found no evidence of differences in oral hygiene levels among clear aligners, self-ligated brackets, and conventional elastomeric ligated brackets after 18 months of active orthodontic treatment. REGISTRATION: The trial is registered at ClinicalTrials.gov (NCT02745626). PROTOCOL: The protocol was not published before trial commencement.

Differences in Lip Support with and without Labial Flanges in a Maxillary Edentulous Population - Part 3: Unblinded and Discriminatory Subjective Analysis.

PURPOSE: To study the subjective differences in direct lip support assessments and to determine if dentists and laypeople are able to discern and correctly identify direct changes in lip support between flange and flangeless dentures. MATERIALS AND METHODS: A random sample of 20 maxillary edentulous patients described in part 2 of the study was used for analysis. A total of 60 judges comprising 15 general dentists, 15 prosthodontists, and 30 laypeople, the majority of who were distinct from part 2 of the study, were recruited. All images used in this study were cropped at the infraorbital level and converted to black and white tone, to encourage the judges to focus on lip support. The judges were un-blinded to the study objectives and told what to look for, and were asked to rate the lip support of each of the 80 images on a 100 mm visual analog scale (VAS). The judges then took a discriminatory sensory analysis test (triangle test) where they were required to correctly identify the image with a flangeless denture out of a set of 3 images. Both the VAS and triangle test ratings were conducted twice in a random order, and mean ratings were used for all analyses. RESULTS: The overall VAS ratings of lip support for images with flangeless dentures were slightly lower compared to images with labial flanges, and this difference was statistically significant (p < 0.0001). This was true for both profile and frontal images. However, the magnitude of these differences was too small (no greater than 5 mm on a 100-mm scale) to be clinically significant or meaningful. The differences in VAS ratings were not significant between the judges. For the triangle test, judges overall correctly identified the flangeless denture image in 55% of frontal image sets and 60% of profile image sets. The difference in correct identification rate between frontal and profile images was statistically significant (p < 0.0001). For frontal and profile images, prosthodontists had the highest correct identification rate (61% and 69%), followed by general dentists (53% and 68%) and by laypeople (53% and 50%). The difference in correct identification rate was statistically significant between various judges (p = 0.012). For all judges, the likelihood of correctly identifying images with flangeless dentures was significantly greater than 1/3, which was the minimum chance for correct identification (p < 0.0001). CONCLUSIONS: Removal of a labial flange in a maxillary denture resulted in slightly lower ratings of lip support compared to images with a labial flange, but the differences were clinically insignificant. When judges were forced to look for differences, flangeless dentures were detected more often in profile images. Prosthodontists detected the flangeless dentures more often than general dentists and laypeople.

Clinical Factors Affecting the Accuracy of Guided Implant Surgery-A Systematic Review and Meta-analysis.

OBJECTIVES: To systematically review the current dental literature regarding clinical accuracy of guided implant surgery and to analyze the involved clinical factors. MATERIAL AND METHODS: PubMed and Cochrane Central Register of Controlled Trials were searched. Meta-analysis and meta-regression analysis were performed. Clinical studies with the following outcome measurements were included: (1) angle deviation, (2) deviation at the entry point, and (3) deviation at the apex. The involved clinical factors were further evaluated. RESULTS: Fourteen clinical studies from 1951 articles initially identified met the inclusion criteria. Meta-regression analysis revealed a mean deviation at the entry point of 1.25 mm (95% confidence interval [CI]: 1.22-1.29), 1.57 mm (95% CI: 1.53-1.62) at the apex, and 4.1° in angle (95% CI: 3.97-4.23). A statistically significant difference (P < .001) was observed in angular deviations between the maxilla and mandible. Partially guided surgery showed a statistically significant greater deviation in angle (P < .001), at the entry point (P < .001), and at the apex (P < .001) compared with totally guided surgery. The outcome of guided surgery with flapless approach indicated significantly more accuracy in angle (P < .001), at the entry point (P < .001), and at apex (P < .001). Significant differences were observed in angular deviation based on the use of fixation screw (P < .001). CONCLUSIONS: The position of guide, guide fixation, type of guide, and flap approach could influence the accuracy of computer-aided implant surgery. A totally guided system using fixation screws with a flapless protocol demonstrated the greatest accuracy. Future clinical research should use a standardized measurement technique for improved accuracy.