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.

Accuracy of direct insertion of TADs in the anterior palate with respect to a 3D-assisted digital insertion virtual planning.

BACKGROUND: Direct and 3D-assisted methods are an available alternative when inserting temporary anchorage devices (TADs) in the anterior palate for orthodontic anchorage. This study aimed to evaluate the differences between a planned insertion versus a direct method on digital models. SETTINGS AND SAMPLE POPULATION: Seventy TADs were inserted by the direct insertion method in 35 patients who needed palatal TADs for orthodontic anchorage. For each patient, placement was independently planned by the superimposition of lateral cephalograms and corresponding plaster models. After mini-implant placement, impressions were taken with scanbodies. For the measurement of both linear and angle deviations, virtual planning models and postoperative oral scans were compared using 3D software for automatic surface registration and calculations. RESULTS: Comparing TADs positioned by the direct method and the digitally planned method, a mean linear distance was found of 2.54 ± 1.51 mm in the occlusal view and 2.41 ± 1.33 mm in the sagittal view. No significant difference has been found between TADs positioned in the right and left palatal sides. A mean distance of 7.65 ± 2.16 mm was found between the tip of the digitally planned TAD and the central incisors root apex. CONCLUSIONS: Both direct and 3D-assisted TAD insertion methods are safe and accurate in the anterior palate. However, the use of insertion guides facilitates TAD insertion, allowing less-experienced clinicians to use palatal implants.

Vitamin E enriched diet increases the rate of orthodontic tooth movement.

INTRODUCTION: Vitamin E is a popular antioxidant suggested to affect bone turnover. However, the effects of a vitamin E enriched diet on the rate of tooth movement are unknown. Therefore, this study aimed to evaluate tooth movement in rats receiving a vitamin E enriched diet. In addition, we examined bone remodeling in experimental and control rats. METHODS: Thirty-two 6-week-old male rats were divided into 4 groups: (1) group 1 (n = 8): orthodontic tooth movement (OTM) for 4 days + regular diet; (2) group 2 (n = 8): OTM for 14 days + regular diet; (3) group 3 (n = 8): OTM for 4 days + vitamin E diet; and (4) group 4 (n = 8) - OTM for 14 days + vitamin E diet. Maxillary alveolar bones and femurs of rats were analyzed by microcomputed tomography and histology. RESULTS: Rats fed a vitamin E diet presented an increased OTM rate at days 4 and 14. We found an increased number of osteoclasts and decreased bone volume in the vitamin E diet group at day 14 of OTM. In addition, there was increased expression of the microphthalmia-associated transcription factor in the alveolar bone of the vitamin E diet group. In contrast, there was no difference in bone remodeling in femurs or alveolar bone at the control side. CONCLUSIONS: We found that an enriched vitamin E diet increases the rate of OTM in rats, suggesting that vitamin E may be useful as an avenue to accelerate OTM.

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 effect of differential force system and minimal surgical intervention on orthodontic tooth movement and root resorption.

OBJECTIVE: The primary objective of this study was to quantify the orthodontic tooth movement (OTM) and orthodontically induced root resorption (OIRR) with differential force system in conjunction with minimal surgical insult. MATERIAL AND METHODS: 15-week-old, 48 male Wistar rats were used in the research and were randomly divided into six groups: 1. Group 1 (8 Wistar rats): OTM for 14 days with 8-g force; 2. Group 2 (8 Wistar rats): OTM for 14 days with 25-g force; 3. Group 3 (8 Wistar rats): OTM for 14 days with 100-g force; 4. Group 4 (8 Wistar rats): OTM for 14 days with 8-g force and alveolar decortications (ADs); 5. Group 5 (8 Wistar rats): OTM for 14 days with 25-g force and ADs; 6. Group 6 (8 Wistar rats): OTM for 14 days with 100-g force and ADs. A nickel-titanium spring was used to protract the molar mesially using maxillary incisors as an anchorage. ADs (minimal surgical insult) were done using a hand piece and a round bur, adjacent to the left first maxillary molar on the palatal alveolar bone. After 14 days of OTM, Wistar rats were killed and microfocus computed tomography and histological analysis were performed. RESULTS: The 100-g group showed significant increase (P < 0.05) in OTM. However, with ADs, the OTM was significantly higher (P < 0.05) in 8 and 100 g. In addition, with ADs, there is significant increase (P < 0.05) in OIRR and significant decrease (P < 0.05) in bone volume fraction. Histological quantification of tartrate-resistant acid phosphatase indicated a significant increase (P < 0.05) in the number of osteoclasts with ADs when compared without ADs. CONCLUSIONS: Light force in conjunction with ADs are optimal to accelerate the OTM. Additionally, ADs increases the OIRR.

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.

Raloxifene administration enhances retention in an orthodontic relapse model.

BACKGROUND AND OBJECTIVES: Orthodontic relapse is a physiologic process that involves remodelling of the alveolar bone and principle periodontal ligament fibres. Raloxifene is an Food and Drug Administration (FDA)-approved selective oestrogen receptor modulator that inhibits systemic bone loss. In our study, we examined the effects of Raloxifene on alveolar bone modelling and orthodontic relapse in a rodent model. MATERIALS AND METHODS: The efficacy of raloxifene was evaluated in 15-week-old male Wistar rats, 8 in each group (Control, Raloxifene, Raloxifene + 7-day relapse, Raloxifene + 14-day relapse) for a total of 42 days. All animals had 14 days of orthodontic tooth movement with a closed nickel-titanium coil spring tied from incisors to right first molar applying 5-8 gm of force. On the day of appliance removal, impression was taken with silicon material and the distance between first molar and second molar was filled with light-cured adhesive resin cement for retention phase. Raloxifene Retention, Raloxifene Retention + 7D, Raloxifene Retention + 14D groups received 14 daily doses of raloxifene (2.0 mg/kg/day) subcutaneously after orthodontic tooth movement during retention. After 14 days of retention, the retainer was removed and right first molar was allowed to relapse for a period of 14 days. Raloxifene injection continued for the Raloxifene + 14-day relapse group during relapse phase too. Control group received saline injections during retention. Animals were euthanized by CO2 inhalation. The outcome measure included percentage of relapse, bone volume fraction, tissue density, and histology analysis using tartrate-resistant acid phosphatase staining and determining receptor activator of nuclear factor-кB-ligand (RANKL) and osteoprotegerin expression. RESULTS: Raloxifene Retention + 14D group had significantly less (P < 0.05) orthodontic relapse when compared with other groups. There was a significant increase (P < 0.05) in bone volume fraction and tissue density in the Raloxifene Retention + 14D group when compared with other groups. Similarly, there was significant decrease in number of osteoclasts and RANKL expression in Raloxifene Retention + 14D group when compared with Raloxifene Retention + 7D group (P < 0.05). CONCLUSION: Raloxifene could decrease post-orthodontic treatment relapse by decreasing bone resorption and indirectly enhancing bone formation.

Injectable RANKL sustained release formulations to accelerate orthodontic tooth movement.

BACKGROUND: Accelerating orthodontic tooth movement (OTM) through biologically effective methods, such as increasing osteoclast-mediated alveolar resorption, could effectively shorten treatment time. OBJECTIVE: To evaluate an injectable formulation containing receptor activator of nuclear factor kappa-B ligand (RANKL) on the OTM. MATERIALS AND METHODS: We fabricated a RANKL formulation from 100 µl of 100 µg/ml RANKL adsorbed on 10 mg of poly(lactic acid-co-glycolic acid) microspheres embedded in a 10 wt% aqueous hydroxyethyl cellulose carrier gel. We characterized these formulations for the rate of RANKL release, and then tested for bioactivity using in vitro cell culture. In vivo OTM studies were conducted using 15 week old male Wistar rats for 14 days. We injected the RANKL formulations palatal to the left maxillary first molar and accomplished OTM with a nickel-titanium (NiTi) coil spring applying 5-8 g force. Control groups involved the application of NiTi coil spring with and without placebo formulation. The outcome measure included the distance of tooth movement, bone volume fraction, tissue density, and root volume determined with micro-computed tomography. We determined the amount of osteoclast activity using tartrate-resistant acid phosphatase (TRAP) staining. RESULTS: These formulations were able to sustain the release of RANKL for more than 30 days, and the released RANKL showed a positive effect on mice osteoclast precursor cells (RAW 264.7). Reported injectable RANKL formulations were effective in accelerating OTM compared with other control groups, with 129.2 per cent more tooth movement than no formulation and 71.8 per cent more than placebo formulation, corresponding with a significant increase in the amount of TRAP activity. We did not observe any significant differences in root resorption between the groups. CONCLUSION: Our study shows a significant increase in OTM with injectable formulations containing RANKL.

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.

Is Short Root Anomaly (SRA) a risk factor for increased external apical root resorption in orthodontic patients? A retrospective case control study using cone beam computerized tomography.

OBJECTIVES: To evaluate the amount of external apical root resorption (EARR) secondary to orthodontic treatment in patients with Short Root Anomaly (SRA) compared to patients with average root lengths using Cone Beam Computed Tomography (CBCT). SETTINGS AND SAMPLE POPULATION: Cone beam computed tomography scans of 23 SRA and 26 control patients were selected from 232 pretreatment scans from a single private practice. MATERIALS AND METHODS: Cone beam computed tomography scans before (T1) and after orthodontic treatment (T2) were evaluated for differences in the change in tooth and root length of the maxillary incisors between both groups. Gender, treatment duration and age were examined as covariates. RESULTS: The mean values for root and tooth length of the maxillary incisors decreased by a range of 0.6 to 1.3 mm after orthodontic treatment. There was no significant difference between the groups for the majority of the measurements although there was a trend for less EARR in the SRA group. The maxillary left central incisor had significantly less proportional and non-proportional loss in tooth length in the SRA group. Age, gender and treatment duration were not associated with change in the proportional and non-proportional lengths for both groups. CONCLUSION: Patients with SRA did not exhibit a significant difference in the proportional and non-proportional change of length after orthodontic treatment when compared to the controls for most measurements. Only tooth length for the maxillary left central incisor had significantly less reduction after orthodontic treatment for both the proportional and non-proportional measurements in the SRA group compared to the control group.

Retreatment of a patient: Orthognathic surgery-first approach with customized lingual appliances combined with miniplate anchorage.

Orthognathic surgery is necessary when a patient's major complaints include skeletal discrepancies that cannot be corrected with orthodontic treatment alone. Currently, orthognathic surgery can be performed through conventional and surgery-first approaches. Some advantages are attributed to the surgery-first approach, such as shortened treatment time and immediate esthetic improvement. The aim of this case report is to present the retreatment of a patient presenting with a skeletal Class III malocclusion, with maxillary retrusion and mandibular protrusion, who was successfully treated with the surgery-first approach and customized lingual appliances, combined with miniplate anchorage in the postoperative orthodontic treatment. The total orthodontic treatment time was 8 months.

The effect of the extent of surgical insult on orthodontic tooth movement.

OBJECTIVE: The primary objective of this study was to investigate how the extent of surgical insult affects the orthodontic tooth movement (OTM) and the alveolar bone modelling and remodelling in a rodent model. MATERIAL AND METHODS: 15-week-old male Wistar rats were used in the research and they were randomly divided into three treatment groups: (1) OTM only (N = 8); (2) OTM + 2 alveolar decortication (AD) (less surgical insult) (N = 8); and (3) OTM + 4 AD (more surgical insult) (N = 8). A nickel-titanium spring delivering 5-8 g of force was used to protract the molar mesially using maxillary incisors as an anchorage. AD was done using a hand piece and a round bur, adjacent to the left first maxillary molar on the palatal alveolar bone. After 14 days of OTM Wistar rats were killed and microfocus computed tomography and histological analysis were performed. RESULTS: The OTM + 4AD group presented with a significant increase (P < 0.05) in the rate of tooth movement when compared to OTM + 2AD group and OTM only group. In addition, the OTM + 4AD group had a significant decrease in bone volume and tissue density (P < 0.05) and a significant increase (P < 0.05) in the trabecular spacing and trabecular thickness when compared to OTM only. Histological quantification of tartrate-resistant acid phosphatase indicated a significant percent increase (P < 0.05) in OTM + 4AD group, when compared to OTM + 2AD and OTM only group. RESULTS: Increased surgical insult increases the rate of OTM. Additionally, increased surgical insult decreases the bone volume and the tissue density.

Change in alveolar bone level of mandibular second and third molars after second molar protraction into missing first molar or second premolar space.

OBJECTIVE: To investigate the factors associated with the change in alveolar bone level of mandibular second and third molars after second molar protraction into the space of the missing first molar (L6) or second premolar (LE). METHODS: Fifty-one patients in whom space of the missing L6 or LE was treated with second molar protraction (13 males, 38 females, mean age 19.6 ± 4.7 years) from 2003 to 2015 were included. The alveolar bone level and position and angulation of the mandibular second and third molars were measured in panoramic radiographs at pre-treatment (T1), and after the alignment of the third molars following second molar protraction (T2). Factors associated with alveolar bone loss on the distal aspect of the mandibular second molars were assessed using linear regression analysis. RESULTS: Age at T1 (P < 0.001) and third molar angulation at T1 (P = 0.002) were significant factors for the prediction of alveolar bone level distal to the second molars. LIMITATION: This study used two-dimensional panoramic radiographs, and we could observe only the interproximal bone level. CONCLUSIONS: After second molar protraction into the missing first molar or second premolar space, mandibular second molars may exhibit alveolar bone resorption in the distal root in older patients and in those with mesially tilted third molars before treatment.

Loading of the Condylar Cartilage Can Rescue the Effects of Botox on TMJ.

The purpose of this study is to evaluate whether the effects of botulinum neurotoxin (botox) injection into the masseter in the mandibular condylar cartilage (MCC) and subchondral bone could be rescued by compressive loading of the temporomandibular joint (TMJ). Twenty-four 6-week-old female mice (C57BL/6J) were used. Mice were divided in three groups: (1) Botox (n = 8); (2) Botox plus loading (n = 8); (3) Pure control (n = 8). Bone labels (3 and 1 day before sacrifice) and the proliferation marker EdU (2 and 1 day before sacrifice) were intraperitoneally injected into all groups of mice. Condyles were dissected and examined by micro-CT and histology. Sagittal sections of condyles were stained for TRAP, alkaline phosphatase, EdU, TUNEL, and toluidine blue. In addition, immunostaining for pSmad, VEGF, and Runx2 was performed. Bone volume fraction, tissue density, and trabecular thickness were significantly decreased on the subchondral bone of botox-injected side when compared to control side and control mice, 4 weeks after injection. Furthermore, histological analysis revealed decrease in mineralization, matrix deposition, TRAP activity, EdU, and TUNEL-positive cells in the MCC of the botox-injected side, 4 weeks after injection. However, compressive loading reversed the reduced bone volume and density and the cellular changes in the MCC caused by Botox injection. TMJ compressive loading rescues the negative effects of botox injection into the masseter in the MCC and subchondral bone.

The effects of alveolar decortications on orthodontic tooth movement and bone remodelling in rats.

Objectives: Alveolar decortication (AD) is a minimally invasive procedure that can be performed in the orthodontic office as an intervention to accelerate tooth movement. There is a gap in the literature evaluating the earlier and delayed responses after AD using lighter orthodontic forces in a rat model. Therefore, the aim of this study was to determine the effects of AD in the amount of orthodontic tooth movement and on alveolar bone remodelling in a rodent model, after 7 or 14 days. Materials and methods: A total of 32 15-week-old male Wistar rats were used in four treatment groups: (1) orthodontic spring only (7 days), (2) orthodontic spring only + AD (7 days), (3) orthodontic spring only (14 days), and (4) orthodontic spring only + AD (14 days). A closed coil nickel-titanium spring delivering 8-10 g of force was used to move the molar mesially. Alveolar decortication was done using a high speed, quarter round bur adjacent to the left first maxillary molar, on the palatal alveolar bone. At each endpoint, rats were sacrificed and microfocus computed tomography and histological analysis were performed. Results: The spring + AD group presented with a significant increase in the rate of tooth movement when compared with spring only group, 7 and 14 days after the beginning of the experiments. In addition, the spring + AD group had a significant decrease in bone volume and tissue density and a significant increase in the trabecular spacing and the number of osteoclasts at 7 and 14 days. Furthermore, a fibrous tissue was found to replace the alveolar bone in the spring + AD group at day 14. Conclusion: Alveolar decortications enhanced bone remodelling around the tooth movement region and could be used as an adjunct surgical procedure to accelerate the rate of tooth movement.

Efficiency of piezotome-corticision assisted orthodontics in alleviating mandibular anterior crowding-a randomized clinical trial.

OBJECTIVES: The aim of this clinical trial was to investigate the duration of mandibular-crowding alleviation with piezotome-corticision orthodontics compared with conventional orthodontics. DESIGN: Single-centre, two-arm parallel group randomized controlled trial. SETTING: Orthodontic clinic at the University of Connecticut. ETHICAL APPROVAL: The study was approved by the Institutional Review Board (IRB # 12-0147-2). SUBJECTS AND METHODS: Forty-one adult subjects from a single centre with more than 5mm of mandibular anterior crowding were randomly allocated using block randomization into experimental and control groups. The experimental group received a corticision procedure with a piezotome on the labial aspect of the mandibular incisors in conjunction to a self-ligation fixed orthodontic appliance. The control group received the self-ligation fixed orthodontic appliance and no corticision. Same archwire sequence (0.014 inch followed by 0.014 × 0.025 inch copper-nickel-titanium) was followed for both groups. Mandibular study casts taken every 4-5 weeks were used to assess changes in the irregularity index by blinded outcome assessors. OUTCOME MEASURES: The time to alignment was calculated in days. RESULTS: Twenty-nine subjects (16 experimental and 13 control) completed the study. Overall, no significant difference in the time required to correct mandibular crowding with piezotome-corticision assisted (102.1 ± 34.7 days; 95% CI, 83.6 to 120.6) and conventional orthodontics (112 ± 46.2 days; 95% CI, 84-139.9) was observed. No complications with treatment or unintended consequences were observed on any of the subjects. LIMITATIONS: A high attrition rate. CONCLUSIONS: This randomized clinical trial found no evidence that piezotome-corticision assisted orthodontics was more efficient in alleviating mandibular anterior crowding. REGISTRATION: ClinicalTrials.gov, Identifier: NCT02026258. FUNDING: Division of Orthodontics, University of Connecticut. CONFLICT OF INTEREST: None.

Bone Response of Loaded Periodontal Ligament.

The tooth-periodontal ligament-alveolar bone complex acts symbiotically to dissipate the mechanical loads incurred during mastication and/or orthodontic tooth movement. The periodontal ligament functions both in the tension and compression. At the molecular and celleular levels, the loads in the periodontal ligament trigger mechanobiological events in the alveolar bone, which leads to bone modeling and remodeling. The current review focuses on the bone response to mechanical loading of the periodontal ligament on the tension and pressure sides. Understanding the bone response has major implications for dentistry, including a better understanding of the different types of orthodontic tooth movement.

Management of severely impacted mandibular canines and congenitally missing mandibular premolars with protraction of autotransplanted maxillary premolar.

Transmigrated mandibular canines increase the treatment complexity in terms of both anchorage and biomechanical planning. Additionally, a Class II malocclusion with a deep overbite and associated dental anomalies such as hypodontia can further increase the treatment complexity and the overall treatment time. This case report describes the successful interdisciplinary treatment of a patient, aged 12.5 years, with transmigrated and severely impacted mandibular canines and congenitally missing mandibular second premolars. The transmigrated mandibular right canine was extracted, and a maxillary second premolar was autotransplanted to the missing mandibular right second premolar site with the aid of a stereolithographic donor tooth replica fabricated with 3-dimensional cone-beam computed tomography and a rapid prototyping technique. Furthermore, the autotransplanted tooth was protracted by 4 to 5 mm to close the space caused by the extraction of the mandibular right canine. The impacted mandibular left canine was orthodontically guided into its normal position in the arch. Good esthetic outcome and functional occlusion were achieved.