Evaluation of expansion forces of five pure bone-borne maxillary expander designs anchored with orthodontic mini-implants: An in vitro study.

AIM: This in vitro study investigates the limit of expansion forces and torque wrench forces developed by five skeletal bone expander designs (MICRO 2/4 expanders™) for clinical application. MATERIAL AND METHODS: A total of 30 skeletal expanders were placed in artificial bone blocks and mechanically tested, simulating maxillary expansion. Differences in jackscrew (Dentaurum™ [D], Superscrew™ [S] and Powerscrew™ [P]), number of orthodontic mini-implants (OMIs; two or four) and their placement inclinations (parallel 0° or 10° inclination) form five designs (D4/10°, S4/0°, S4/10°, P4/10° and P2/10°). Expansion forces and torque wrench values were registered, and radiographs were made initially and after 4 mm of expansion. Stress-strain curves were obtained after successive activations and the statistical analysis was performed as appropriate. RESULTS: Plastic deformations in the OMIs and jackscrew occurred around the activation numbers 11-13, with torque wrench values in the range of 500-700 cN. The maximum expansion forces in expanders with four OMIs varied from 93.0 (D4/10°) to 166.6 N (P4/10°) whereas two OMI expanders (P2/10°) registered forces of 79.4 N. Radiographs revealed during loads bending forces (S4/00°, S4/10°) with jackscrew and OMIs deformation in a convex shape, and shear forces (P4/10°, P2/10°) demonstrated only OMIs deformation in a concave shape, providing 15% more expansive force. The jackscrew D4/10° did not have any deformation, but its wire key did not allow reliable activations from activation number 10 and compared to S4/10° and P4/10°, these expanders provided greater expansion forces (P = 0.000 and P = 0.032, respectively). CONCLUSION: The different results obtained in stability and expansion forces indicate that if the activations are carried out under extreme conditions, they may have clinical importance with deformations and non-working expansion mechanics. Jackscrew designs play an important role in expansive forces and expander stability. Torque wrench values can be used clinically as a tool to asses the expansion forces and to avoid deformations.

Success and complication rate of miniscrew assisted non-surgical palatal expansion in adults - a consecutive study using a novel force-controlled polycyclic activation protocol.

INTRODUCTION: Bone-borne miniscrew assisted palatal expansion (MAPE) is a common technique to improve maxillary transverse deficiency in young adolescents. Adult patients usually present a challenge, as they often require additional surgical assisted maxillary expansion (SARPE). There is still no clear statement about non-surgical expansion in adult patients using this technique. The aim of this study was to evaluate the success and complication rate of non-surgical palatal expansion in adults utilizing MAPE with a novel force-controlled polycyclic expansion protocol (FCPC). METHODS: This consecutive study consisted of 33 adult patients with an average age of 29.1 ± 10.2 years (min. 18 years, max. 58 years), including one dropout patient. First, four miniscrews were inserted and after 12-weeks latency, the expander was placed and the FCPC protocol was applied (MAPE group). In case of missing expansion, a SARPE was performed (SARPE group). After maximum expansion, a cone beam CT was made and widening of the midpalatal suture was measured. The outcome variables were successful non-surgical expansion and, with sample size power above 80%, the odds of failed non-surgical expansion and associated complications were evaluated. The primary predictor variable was age. Statistical analysis was performed using R (Version 3.1) to calculate power, to construct various models for measuring the odds of requiring surgical intervention/complications, and others. RESULTS: Successful non-surgical expansion was achieved in 27 patients (84.4%), ranging from 18 to 49 years. Mean age differed significantly between both groups (26.8 ± 8.2 years vs. 41.3 ± 9.9 years; p < 0.001). Mean expansion at the anterior and posterior palate for the MAPE group was 5.4 ± 1.5 mm and 2.5 ± 1.1 mm, respectively. Among these subjects' complications were observed in 18.5%. Age significantly increased the odds of complications (p = 0.019). CONCLUSIONS: 1. The success rate of MAPE among individuals aged 18 to 49 years was 84.4%. 2. A V-shaped expansion pattern in the antero-posterior dimension was mostly observed. 3. Complications were significantly associated with age. 4. A careful expansion protocol seems to be beneficial to prevent unfavorable results in adult patients. TRIAL REGISTRATION: Consecutive cohort study, Review Board No. EK-2-2014/0016.

Is There a Significant Difference in Relapse and Complication Rate of Surgically Assisted Rapid Palatal Expansion Using Tooth-Borne, Bone-Borne, and Orthodontic Mini-Implant-Borne Appliances?

PURPOSE: For surgically assisted rapid palatal expansion (SARPE), studies comparing different devices are missing. The aim was to evaluate expansion, relapse, and the complication rates for 3 different appliances. PATIENTS AND METHODS: In this retrospective cohort study, tooth-borne (TB, n = 29), bone-borne (BB, n = 12), or orthodontic mini-implant (OMI)-borne (n = 13) appliances were used for SARPE in 2 clinical centers. Patients presenting with a maxillary width discrepancy greater than 5 mm were included. Measurements of cast models and radiographs were performed preoperatively, immediately after consolidation, and at 1 year postoperatively. All distances were measured between canines, premolars, and molars. Complications (tooth damage, infection, technical failure) were evaluated. The outcome variables were expansion, relapse, and complications. Type of appliance was selected as predictor variable. Within- and between-group differences regarding expansion, relapse, and complications for the 3 appliances were statistically analyzed. RESULTS: In 54 patients (aged 28.8 ± 8.6 years), mean expansion (±standard deviation) for the TB, BB, and OMI appliances immediately after consolidation was 5.29 ± 1.39 mm, 5.22 ± 1.72 mm, and 3.81 ± 2.19 mm, respectively, at the dental level, and 5.51 ± 1.40 mm, 4.66 ± 2.03 mm, and 3.51 ± 1.66 mm, respectively, at the bone level. Mean (±standard deviation) relapse for the TB, BB, and OMI appliances at 1 year postoperatively measured 1.44 ± 1.01 mm, 0.76 ± 1.37 mm, and 0.27 ± 1.63 mm, respectively, at the tooth level and 1.19 ± 0.93 mm, 0.71 ± 0.96 mm, and 0.12 ± 1.56 mm, respectively, at the bone level. Analysis of variance and the Tukey test showed significant differences between the TB and OMI appliances for expansion and relapse (P = .034 and P = .024, respectively). The overall complication rate differed significantly (P < .001), with rates of 17.2%, 66.7%, and 15.4% for the TB, BB, and OMI appliances, respectively. CONCLUSIONS: BB and OMI appliances resulted in less relapse. Owing to the high complication rate, the further use of BB appliances is questionable.

Skeletal-versus soft-tissue-based cephalometric analyses: is the correlation reproducible?

OBJECTIVES: Dentofacial deformities can be analyzed by skeletal and soft tissue cephalometric analysis (CA). The aim was to evaluate the difference in reproducibility between both methods. MATERIALS AND METHODS: Lateral cephalograms of 112 patients (65 females and 47 males, 27.7 ± 9.0 years) were oriented in natural head position (NHP) and digitized. The distances of skeletal (SNA, SNB, SnPog) and soft tissue (A', B' and Pog') landmarks relative to the respective norm values and the angles between the Nasion Sella line (NSL) and Frankfurt horizontal (FH) to NHP were measured for statistical evaluation and compared with respective data of an adult control group (CG) with class I occlusion and harmonic facial balance. RESULTS: The mean differences (mm ± SD) of skeletal and soft tissue landmarks were -2.4 ± 4.4 (A), -7.0 ± 9.3 (B), -6.3 ± 11.2 (Pog), -0.9 ± 1.8 (A'), -4.7 ± 6.2 (B'), and -6.1 ± 7.8 (Pog'), respectively. Pearsons's correlation (r) between the measurements of SNA/A', SNB/B' and SNPog/Pog' were r = .158 (p = .092), r = .662 (p < .001) and r = .655 (p < .001), respectively. The mean (±SD) angles between NSL and FH to NHP were -9.8° ± 5 and 0.0° ± 3.9, respectively. CONCLUSION: Variability of cranial-based measurements could give a possible explanation for the high variation and the low reproducibility of skeletal cephalometric analysis with soft tissue measurements. Soft-tissue cephalometric analysis would probably improve facial analysis and treatment planning.

Stability of the anterior arm of three different Hyrax hybrid expanders: an in vitro study.

INTRODUCTION: The force applied to the teeth by fixed orthopaedic expanders has previously been studied, but not the force applied to the orthodontic mini-implant (OMI) used to expand the maxilla with Hyrax hybrid expanders (HHE). OBJECTIVE: The aim of this article was to evaluate the clinical safety of the components (OMI, abutment and double wire arms) of three different force-transmitting systems (FTS) for conducting orthopaedic maxillary expansion: Jeil Medical & Tiger Dental™, Microdent™ and Ortholox™. METHODS: For the realization of this in vitro study of the resistance to mechanical load, three different abutment types (bonded, screwed on, and coupling) and three different OMIs' diameters (Jeil™ 2.5 mm, Microdent™ 1.6 mm and Ortholox™ 2.2 mm) were used. Ten tests for each of these three FTS were carried out in a static lateral load in artificial bone blocks (Sawbones™) by a Galdabini universal testing machine, then comparing its performance. Comparisons of loads, deformations and fractures were carried out by means of radiographs of FTS components in each case. RESULTS: At 1- mm load and within the elastic deformation, FTS values ranged from 67 ± 13 N to 183 ± 48 N. Under great deformations, Jeil & Tiger™ was the one who withstood the greatest loads, with an average 378 ± 22 N; followed by Microdent™, with 201 ± 18 N, and Ortholox™, with 103 ± 10 N. At 3 mm load, the OMIs shaft bends and deforms when the diameter is smaller than 2.5 mm. The abutment fixation is crucial to transmit forces and moments. CONCLUSIONS: The present study shows the importance of a rigid design of the different components of HHEs, and also that HHEs would be suitable for maxillary expansion in adolescents and young adults, since its mean expansion forces exceed 120N. Furthermore, early abutment detachment or smaller mini-implants diameter would only be appropriate for children.

Stability of the anterior arm of three different Hyrax hybrid expanders: an in vitro study

ABSTRACT Introduction: The force applied to the teeth by fixed orthopaedic expanders has previously been studied, but not the force applied to the orthodontic mini-implant (OMI) used to expand the maxilla with Hyrax hybrid expanders (HHE). Objective: The aim of this article was to evaluate the clinical safety of the components (OMI, abutment and double wire arms) of three different force-transmitting systems (FTS) for conducting orthopaedic maxillary expansion: Jeil Medical & Tiger Dental™, Microdent™ and Ortholox™. Methods: For the realization of this in vitro study of the resistance to mechanical load, three different abutment types (bonded, screwed on, and coupling) and three different OMIs' diameters (Jeil™ 2.5 mm, Microdent™ 1.6 mm and Ortholox™ 2.2 mm) were used. Ten tests for each of these three FTS were carried out in a static lateral load in artificial bone blocks (Sawbones™) by a Galdabini universal testing machine, then comparing its performance. Comparisons of loads, deformations and fractures were carried out by means of radiographs of FTS components in each case. Results: At 1- mm load and within the elastic deformation, FTS values ranged from 67 ± 13 N to 183 ± 48 N. Under great deformations, Jeil & Tiger™ was the one who withstood the greatest loads, with an average 378 ± 22 N; followed by Microdent™, with 201 ± 18 N, and Ortholox™, with 103 ± 10 N. At 3 mm load, the OMIs shaft bends and deforms when the diameter is smaller than 2.5 mm. The abutment fixation is crucial to transmit forces and moments. Conclusions: The present study shows the importance of a rigid design of the different components of HHEs, and also that HHEs would be suitable for maxillary expansion in adolescents and young adults, since its mean expansion forces exceed 120N. Furthermore, early abutment detachment or smaller mini-implants diameter would only be appropriate for children.

RESUMO Introdução: a força aplicada sobre os dentes por expansores ortopédicos fixos já foi estudada antes, mas não a força aplicada sobre os mini-implantes ortodônticos (MIOs) usados para expandir a maxila com expansores do tipo Hyrax híbrido (EHH). Objetivo: o objetivo desse artigo foi avaliar a segurança clínica dos componentes (MIO, abutment de fixação, e braços de fio duplo) de três sistemas de transmissão de força (STF) usados para expansão ortopédica da maxila: Jeil Medical & Tiger Dental™, Microdent ™ e Ortholox ™. Métodos: para realizar esse estudo in vitro sobre a resistência à carga mecânica, foram usadas três tipos de sistema de fixação (colado, aparafusado e coupling) e MIOs de três diâmetros diferentes (Jeil™ 2,5 mm; Microdent™ 1,6 mm e Ortholox™ 2,2 mm), com suas respectivas mecânicas de STF. Foram realizados 10 testes para cada STF, usando uma carga lateral estática em blocos de osso artificial (Sawbones™), com uma máquina universal de testes e, depois, comparou-se, por meio de radiografias, os desempenhos, levando-se em consideração as cargas, deformações e fraturas dos componentes de cada STF. Resultados: com a carga a 1 mm e sem exceder o limite de deformação elástica, os valores dos STFs variaram de 67 ± 13 N a 183 ± 48 N. Sob deformações maiores, o sistema Jeil & Tiger™ foi o que apresentou maior resistência às cargas elevadas, com valor de 378 ± 22 N; seguido pelo Microdent™, com 201 ± 18 N, e Ortholox™, com 103 ± 10 N. Com a carga a 3 mm, o eixo do MIO se dobrou e deformou quando seu diâmetro era menor que 2,5 mm. O abutment de fixação é crucial para a transmissão das forças e momentos. Conclusões: o presente estudo evidenciou a importância da rigidez no design dos diferentes componentes dos STFs dos EHH. Também revelou que eles são adequados para a expansão da maxila em adolescentes e adultos jovens, pois as forças de expansão, em média, excederam os 120N. Além disso, a desconexão precoce do abutment ou o uso de mini-implantes de menor diâmetro no design do STF seriam apropriados apenas em crianças.

Comparison of two preoperative protocols for mandibular symphyseal distraction osteogenesis to reduce the risk of tooth damage.

Two techniques to separate the lower incisors prior to mandibular symphyseal distraction osteogenesis (MSDO) were evaluated with respect to avoiding tooth damage. METHODS: Fifty patients (20.2 ± 7.0 years) requiring MSDO were treated with a tooth-borne appliance by utilizing two preoperative protocols to separate the central incisors: i) brackets and a V-bent wire with an open coil spring (two-step; TS; n = 24) and ii) a wire attached from the appliance to the central incisors with subsequent dento-alveolar expansion prior to surgery (one-step; OS; n = 26). The distance between the lower incisors was measured preoperatively on radiographs and measurements at the cast models were performed. Complications and radiographs were analyzed. RESULTS: The mean distance (±SD) between the lower central incisors for OS and TS prior to surgery was 3.44 ± 1.05 and 3.18 ± 1.13 mm, respectively. The mean expansion for OS and TS was 4.3 ± 2.9 and 4.3 ± 2.7 mm at the dental level and 3.8 ± 3.2 and 4.0 ± 2.1 mm at the bone level, respectively. Four patients undergoing the TS and one patient undergoing the OS showed transient dental complications. CONCLUSION: Pre-surgical dento-alveolar expansion by utilizing a one-step technique to separate the lower central incisors reduces the risk of permanent tooth damage and weakens the mandibular bone in the midline.

Effects of a hinged expansion screw for median mandibular distraction treatment on the lower first molars regarding tooth inclination and intermolar transverse distance.

OBJECTIVES: The goal of this study was to assess the extent to which median mandibular distraction via a cemented and screw-retained full-coverage splint appliance employing a hinged expansion screw causes inclination changes in the lower first molars and widens the dental arch. METHODS: Our study included 17 patients (12 females and 5 males; average age 16 years and 3 months) who presented with transverse space deficits and pronounced dental crowding. Baseline and final mandibular casts reflecting the situations before and after 6 weeks of median distraction therapy were created, scanned, and matched via their coordinate systems. Perpendiculars were drawn at the geometric centers between the cusp tips of teeth 36 and 46 and projected against the frontal plane. The intersection angles yielded single-tooth and total inclination values for both molars, and the difference between the intermolar distances measured at the geometric centers of both teeth provided the amount of transverse expansion. RESULTS: An intraclass correlation coefficient (ICC) of >0.99 was obtained in a series of three measurements. After distraction treatment, the total inclination values between teeth 36 and 46 changed by +2.93 ± 9.14°. The corresponding single-tooth inclinations changed by +0.68 ± 6.32° and -2.25 ± 4.33°, respectively. Both molars underwent similar degrees of buccal or lingual tipping. Compared to a mean expansion of +6.9 ± 1.83 mm at the distraction screw, a distance increase of only +3.77 ± 1.27 mm along the transversal connecting teeth 36 and 46 was recorded. Pearson's correlation coefficient was 0.336 between total tipping and intermolar expansion (p=0.187) and -0.426 between total tipping and patient age (p=0.088). CONCLUSION: Expansion amounts were approximately twice as long at the expansion screw as between the first molars. This V-shaped expansion pattern was due to the hinged connections between each expansion screw and the full-coverage splints. The buccal and lingual tipping of molars measured may be due to varying heights of the posterior alveolar ridge during mixed dentition or to anatomy-related differences in the expansion-screw position. In all cases we observed a mainly parallel opening of the distraction gap on the vertical plane.

Design characteristics, primary stability and risk of fracture of orthodontic mini-implants: pilot scan electron microscope and mechanical studies.

OBJECTIVE: Orthodontic mini-implants (OMIs) are increasingly used in orthodontics but can fail for various reasons. This study investigates the effects of OMI design characteristics on the mechanical properties in artificial bone. MATERIAL AND METHODS: Twelve self-drilling OMIs (2 small, 6 medium, 4 large) from 8 manufacturers were tested for their primary stability in simulated medium-high cancellous bone and the risk to fracture in high-density methacrylate blocks. For the assessments of the maximum insertion torque (IT) and torsional fracture (TF) 5 of each OMI were used and for the pull-out strength (POS) 10. The OMIs were inserted with a torque screwdriver (12 sec/360°) until the bottom at 8 mm depth was reached. OMI designs were analyzed with a scan electron microscope (SEM). RESULTS: SEM images revealed a great variation in product refinement. In the whole sample, a cylindrical OMI shape was associated with higher POS (p<0.001) but lower IT (p=0.002) values. The outer and inner OMI diameters were design characteristics well correlated with POS, IT and TF values (ranging from 0.601 to 0.961). Greater thread depth was related to greater POS values (r= 0.628), although OMIs with similar POS values may have different IT values. Thread depth and pitch had some impact on POS. TF depended mainly on the OMI inner (r= 0.961) and outer diameters (r=0.892). A thread depth to outer diameter ratio close to 40% increased TF risk. CONCLUSION: Although at the same insertion depth the OMI outer and inner diameters are the most important factors for primary stability, other OMI design characteristics (cylindrical vs. conical, thread design) may significantly affect primary stability and torsional fracture. This needs to be considered when selecting the appropriate OMI for the desired orthodontic procedures.

Effectiveness and safety of a mouthwash containing essential oil ingredients.

The mouthwash, Listerine®, was compounded in 1879 from four essential oils. Later, the oils were replaced by one ingredient per oil with approximately 25% ethanol as a vehicle to keep them in solution. From then on, Listerine® was no longer a medicinal plant product. In 2003, a review by the FDA Subcommittee on Oral Health Care Drug Products for Over-the-Counter Human Use concluded that the product is effective and safe, and a review of studies published in the meantime showed that Listerine® fulfils the consensus criteria for an effective antigingivitis/antiplaque product. However, concerns have been raised about the long-term safety of some of the ingredients, particularly the ethanol content, and in the light of these concerns, the evidence has been re-examined for both the efficacy and safety of Listerine®. In summary, the studies support the claim that Listerine® shows benefit for oral health, but the concerns over its safety remain to be clarified. Until these have been addressed, high risk populations (children, alcohol addicts, patients with genetic deficiencies in ethanol metabolism) should use alcohol-free mouthwashes for the maintenance of oral health.

Three-dimensional measurement of the mandible after mandibular midline distraction using a cemented and screw-fixated tooth-borne appliance: a clinical study.

PURPOSE: The aim of this study was to analyze the 3-dimensional movement of the mandible segments after distraction of the mandibular midline by use of a cemented and screw-fixated tooth-borne appliance. PATIENTS AND METHODS: Twenty patients with transverse deficiencies of the lower arch were included in a consecutive study. Before surgical intervention, a custom-made appliance was cemented to the teeth and also fixed with 2 screws between the teeth on each side. The distraction appliance was activated after 5 days at a rate of 0.6 mm/d. After a consolidation period of 6 weeks, the appliance was removed and an orthodontic retainer was applied. Radiographs and cast models were taken preoperatively and postoperatively, and direct linear measurements were performed at the same intervals. RESULTS: Mean expansion (+/- SD) of the osteotomy line measured on the radiographs for the superior, middle, and inferior part of the mandible was 5.1+/-2.4, 5.9+/-2.8, and 5.7+/-2.9 mm, respectively. The mean overall expansion was 5.6+/-2.6 mm. The width increase of the models between the canines, first premolars, second premolars, first molars, and second molars was 4.2+/-1.8, 5.0+/-2.0, 4.7+/-2.0, 4.3+/-1.7, and 3.6+/-1.3, respectively, at the tooth level and 3.4+/-2.0, 3.6+/-1.8, 3.3+/-1.4, 3.2+/-1.5, and 2.2+/-1.8, respectively, at the bone level. CONCLUSIONS: Expansion of the osteotomy line in the vertical dimension showed a uniform pattern. Lateral movements of the mandibular segments decreased from the symphysis to the gonial angles. The positional changes of the teeth and the bone segments were proportionate. Minimal dental movement was observed.