Initial Phase Of Orthodontic Treatment Research Articles

Comparison of the efficiency of initial dental alignment with Invisalign® aligners changed every 7 or 14 days in mature adults: Randomized clinical trial.

To compare the anterior crowding correction after sequential use of the first 5 aligners between two aligner exchange protocols (7 and 14 days) in mature adult patients. Thirty-six patients over 35 years who received orthodontic treatment with Invisalign® were randomly allocated to two different aligner replacement sequence protocols: Group 1: exchange every 7 days (n = 18); and Group 2: exchange every 14 days (n = 18). All patients were scanned with iTero Element 5D® (Align Technology) in two treatment times: at pre-treatment (T1) and after using the first five aligners (T2). Little's Irregularity Index (LII) and arch widths were evaluated with OrthoCAD software. Intra and intergroup comparisons were performed with the dependent and independent t-tests. The results were considered significant for P < .05. Thirty-five patients completed the study. Both groups' maxillary and mandibular Irregularity Indexesi were significantly lower at T2. There was no significant difference in inter-canine, inter-premolar, and intermolar distances.G2 (14 days) presented a greater decrease in mandibular irregularity than G1 (7 days). Both exchange protocols (7 and 14 days) effectively correct anterior crowding in the initial phase of orthodontic treatment with aligners in mature adult patients. However, the 14-day exchange protocol provided a greater correction in mandibular anterior crowding in the evaluated period than the 7-day exchange protocol.

Orthodontic pain in maxilla and mandible during the first week of orthodontic treatment

Background/Aim: This investigation aimed to evaluate the intensity of self-reported pain and frequency of self-medication with analgesics during the initial phase of orthodontic treatment with fixed appliances and to compare possible differences between the maxillary and mandibular teeth. Material and Methods: In this observational clinical trial 68 patients had similar orthodontic forces (the same bracket-slot and prescription, archwire size and material, and treatment plan) applied on maxillary and mandibular teeth. The patients recorded pain intensity and use of analgesics for the first seven days of treatment. Comparisons between maxillary and mandibular teeth regarding the pain intensity and self-medication frequency were performed by Wilcoxson Signed Ranks Test and McNamara Test for Matched Pairs, respectively. Results: The patients reported moderate pain in both jaws which decreased significantly with each day of treatment. Still, during the initial three days of treatment intensity of pain for maxillary teeth was significantly lower compared to the mandibular teeth. Patients reported analgesics consumption for both jaws, without a statistically significant difference between them. Conclusions: The patients have reported orthodontic pain of higher intensity in the mandibular arch compared to the maxillary arch during the initial phase of orthodontic treatment with fixed appliances.

Clinical Features and Physical Properties of Gummetal Orthodontic Wire in Comparison with Dissimilar Archwires: A Critical Review.

Objective Gummetal is a novel multifunctional alloy which possesses distinctive properties with the potential to refine and amend the efficacy of orthodontic treatment. The objective of this critical literature review was to investigate scientific evidence concerning the mechanical and clinical features of this recently manufactured beta-titanium orthodontic wire. Materials and Methods Electronic databases: PubMed, PMC, Google Scholar, Ovid, and Cochrane Library were searched. Studies investigating the properties of Gummetal orthodontic wire including in vitro and clinical studies were selected, validity was assessed, and data was extracted. The risk of bias was assessed by the Cochrane risk of bias Tool 2.0 in a randomized clinical trial. Results and Discussion. Among 322 papers, 13 papers were selected and divided into two groups: prospective double-blinded randomized clinical trial and in vitro studies. Conclusions The results of this review should be interpreted with caution because of the heterogeneity of the studies. Only single clinical trial paper was found in the literature. The studies reported different characteristics obtained by various methods; thus, it was difficult to objectively compare the results. Low bending strength, low fatigue limit, and high resilience have been confirmed. Gummetal provides lower force than Nitinol and TMA but higher than Supercable wire. Plastic deformation of Gummetal questions its superelasticity. Friction of Gummetal wire is comparable to SS and CoCr wires. Because of its nontoxic chemical composition, Gummetal might be useful in the initial phase of orthodontic treatment for patients suffering from nickel allergy. Further studies are necessary to assess the usefulness of Gummetal in the clinical practice.

Three-dimensional coupling between orthodontic bone remodeling and superelastic behavior of aNiTi wire applied for initial alignment.

NiTi wires are considered as the most appropriate wires to be used during the initial phase of orthodontic treatment. This work presents anumerical method to simulate the coupling between the orthodontic appliance and bone remodeling, which are the two mechanisms responsible for the orthodontic tooth movement. The superelastic behavior of aNiTi wire was integrated in athree-dimensional simulation model to reproduce the long-term bone remodeling coupled with tooth alignment using the finite element method. The orthodontic load was derived by deforming the superelastic wire in order to adopt itself to the original position of irregular teeth. Root form was extracted from cone beam tomography imaging files. As aresult, the teeth were aligned while the wire was recovering its initial shape. The canine was intruded by 0.53 mm, while the neighboring teeth were extruded by 0.44 and 0.46 mm. When the wire was loaded, it generated aload of 4.6 N on the bracket bonded on the canine. This force was active during the first day of the treatment. Then, the force continued to decline until the end of the correction period. The decreasing load delivered from the wire affected the teeth displacements as observed in real situations. Despite the complexity of the presented numerical simulation, this procedure allowed the analysis of the orthodontic forces that were generated in the clinical experiments and of the biomechanical response of the periodontal support elements when using this kind of wire.

Changes in clinical and microbiological parameters of the periodontium during initial stages of orthodontic movement in patients with treated severe periodontitis: A longitudinal site-level analysis.

Applying orthodontic braces makes oral hygiene difficult and increases plaque accumulation, frequently resulting in gingival inflammation. In patients with previous severe periodontitis, this inflammation overlaps with the pre-existing inflammatory challenge and can lead to further progression of periodontal attachment loss. The aim of this study was to assess longitudinal site-level changes as mirrored by clinical and microbiological parameters during the initial remodeling of alveolar bone and the periodontal ligament, produced as an effect of light orthodontic forces in adult patients with severe periodontal disease that underwent standard (non-surgical and conventional surgical) periodontal therapy. Thirteen patients with previously treated severe generalized periodontitis were given fixed orthodontic appliances for re-alignment of teeth misaligned or displaced during the course of periodontitis. Before insertion of orthodontic appliances and at 2, 4, and 6 months of treatment, periodontal clinical parameters were recorded in the same deepest residual pocket of at least 3 mm in each patient. The same pocket was sampled at baseline and after 6 months of orthodontic treatment for the frequency of positive detection of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tanerella forsythia (Tf), Treponema denticola (Td). An average reduction in Pocket Depth by 0.2 mm at the end of the assessment period was identified. The only clinical parameter with statistically significant improvement was bleeding on probing. The frequency of detection of Aa, Pg, Pi, and Tf was not significantly different between baseline and 6 months of treatment, while a marginally significant increase of Td was found. There were no significant differences in the clinical parameters or microflora in the initial phase of orthodontic treatment in patients with reduced periodontal support. By correlating clinical and microbiological data, we concluded that the presence of periopathogens do not negatively influence periodontal health during orthodontic treatment in adult patients treated for severe periodontitis.

Effect of photobiomodulation on pain perception secondary to separator placement

Pain associated with orthodontic treatment is often one of the reasons for dropout during fixed orthodontic treatment. The aim of the present study was to assess the effect of photobiomodulation on pain during the initial phase of orthodontic treatment. A single blind study using a split mouth design was carried out on 24 subjects requiring fixed orthodontic treatment in the age group of 13 to 20 years. The subjects were randomly divided into two groups and elastomeric separators were placed on the mesial and distal aspects of upper and lower first molars. Further, they were subjected to laser irradiation (Photon plus diode laser®, Zolar Technology and Mfg. Co. Inc. Canada, InGaAs based diode laser 980 nm, 100 mW, continuous wave mode) and simulations at four points, i.e. the interdental papilla on the buccal and lingual/palatal aspect mesially and distally accordingly for 10 s each. The subjects were asked to score their pain intensity on a visual analogue scale (VAS) at 5 min, 24 and 48 h post separator placement. The mean score for pain perception for the lased group was significantly lower than the placebo group at both 24 and 48 h. However, no appreciable difference was seen at 5 min post placement. Although a single dose of photobiomodulation subsequent to separator placement does not provide immediate relief, it is significantly effective in reducing pain at 24 and 48 h. However, there was no association of age with pain perception.

A randomized clinical trial investigating pain associated with Bio-kinetic plus nickel–titanium and Conventional nickel-titanium archwires during the initial hours of levelling and aligning the phase of orthodontic treatment

Orthodontic force application leads to periodontal ligament tissue injury and the initiation of acute inflammatory processes. Therefore, it is recommended that light force should be used during orthodontic treatment to minimise tissue damage and subsequent pain and discomfort. The present study was aimed to assess the pain perception between two types of nickel-titanium wires. To investigate and compare the effects of Bio-kinetics plus nickel–titanium and conventional nickel-titanium archwires on pain during the initial hours of the initial phase of orthodontic treatment. To compare and evaluate the pain perception using a Visual Analogue Scale (VAS) between 0.016 Conventional NiTi (Group 1) and Bio-Kinetix Plus NiTi (Group 2) at regular intervals of 24 hours, 48 hours and 72 hours each consisting of a sample size of 7. A total of 14 subjects participated in the study, each group consisting of 7 subjects. The mean pain perception score was 1.71±0.48 and 1.71±0.48 at 0 hours, 2.42±0.97 and 2.71±0.48 at 24 hours, 3.42±0.97 and 2.85±0.69 at 48 hours, 3.85±0.69 and 2.57±0.53 at 72 hours, for Group 1 and Group 2 respectively. There is no significant difference between the two groups, but there is a significant difference (p=0.001) in group 2, by 72 hours, indicating there is a decrease in pain perception. For overall pain, there was no statistically significant difference between the two wires. However, subjects with bio-kinetix plus nickel–titanium archwires had a significantly lower pain at peak level.

Electromyographic Changes in the Masseter and Temporalis Muscles Before and After Orthognathic Surgery in Patients With Mandibular Prognathism.

Evaluate the electromyographic changes in the Masseter (MM) and Temporalis (TM) muscles during voluntary clenching of the teeth both before and after orthognathic surgery in patients aged 18 years and older and diagnosed with mandibular prognathism. Eleven patients with prognathism were included in the study, in all of whom the initial phase of orthodontic treatment had been completed. The orthognathic procedure to reduce prognathism comprised intraoral oblique sliding (or subsigmoid) osteotomy, after which intermaxillary fixation with ligaments in the maxilla and mandible was undertaken in all patients for 6 weeks post-surgery. Electromyographic activity was recorded during the baseline maximum voluntary contraction of the teeth, with the same measurement taken 3 and then 6 months after orthognathic surgery. Significant differences were found in the mean amplitude (17.0 vs 14.7, P = 0.020) and peak-to-peak amplitude (left [761.6 vs 457.0, P = 0.003] and right [676.9 vs 357.4, P = 0.007]) for the MM between the baseline score and 6 months after surgery. Likewise, significant differences were found in the mean amplitude (18.2 vs 25.6, P = 0.009) and peak-to-peak amplitude (left [856.4 vs 1594.2, P = 0.004] and right [804.4 vs 1813.4, P = 0.004]) for the TM between the baseline score and that taken 6 months post-surgery. Only 18.2% (2/11) presented orthodontic appliances problem in the 3 months post-surgery. Electromyographic activity was restored 6 months after the orthognathic surgery. From a clinical perspective, the results obtained confirm that orthognathic surgery has not only an esthetic but also a functional objective in terms of achieving equilibrium and occlusal harmony.

Alveolar bone changes and root resorption concomitant with rectangular NiTi in initial leveling and alignment

Introduction: Fixed orthodontic appliances include a wide variety of archwires used as a means of delivering forces on teeth. As there are a variety of available archwires, it is important to know which is the most efficient during the initial aligning stage of the treatment. During the initial phase of orthodontic treatment, the use of rectangular arch wires has been reported to result in decreased incisor inclination compared to the traditional round NiTi arch wires. Debates still exist regarding the effect of SLB on the alveolar bone and the root length. Aim of the study: The aim of this clinical study is to evaluate the changes in the alveolar bone and the root resorption during initial leveling and alignment with rectangular NiTi arch wires. Materials and methods: The current randomized clinical prospective study was conducted on a total sample of 20 patients, divided into two groups of ten. Group I consisted of 10 patients treated with active self-ligating stainless-steel brackets and round Cu NiTi wires using the conventional sequence for leveling and alignment. Group II consisted of 10 patients treated with active self-ligating stainless-steel brackets and rectangular Cu NiTi archwires for leveling and alignment. CBCTs were taken after achieving the study objectives (post leveling and alignment) to be used for analyzing the study measurements and comparison with the pretreatment CBCT data. Both groups were compared regarding alveolar bone length, alveolar bone thickness and root length. Conclusion: We concluded that there was no significant difference between the two groups concerning alveolar bone length and thickness. However, group II (treated with rectangular Cu NiTi archwires) showed a significant decrease in root length.

Comparison of the Mechanical Properties of Three Commercial Orthodontic NiTi Round Archwires

To compare mechanical properties of three commercial NiTi orthodontic round wires, three commercial brands of NiTi round wire (Nic-China, Ormco-USA, and Smart-Thailand) with sizes 0.014’’, 0.016’’, and 0.018’’were studied. Five specimens each size of each brand were used to test mechanical properties; unloading force (N), spring back (mm), and yield strength (N/mm) with three-point bend test using an Instron Universal Testing Machine. Kolmogorov-Smirnov test and one-way ANOVA were employed to test the differences among groups with statistical difference at p&lt;0.05.The average unloading force from lowest to highest were Ormco, Smart and Nic with 0.014”, Smart, Ormco and Nic with 0.016”and Smart, Nic and Ormco with 0.018”, respectively. The Nic brand had the highest value of unloading force, spring back, and yield strength in all wire sizes, except unloading force 0.018” Ormco and spring back 0.018” Smart. There were no statistically significant differences in unloading forces among all wire sizes. The three brands of commercial orthodontic NiTi wires presented similar unloading force, spring back, and yield strength properties. These mechanical properties are related to lower rates of deformation and are appropriate to be used in the initial phase of orthodontic treatment.

ORTODONTİK TEDAVİNİN BAŞLANGIÇ AŞAMASI SIRASINDAKİ AĞRI - FARKLI YAŞ GRUPLARININ KARŞILAŞTIRILMASI

Amac: Bu calismanin amaci, ortodontik tedavinin baslangic asamasindaki genc hastalarin agri seviyelerinin ileri yasli hastalarinki ile karsilastirilmasidir. Materyal-Metot: Bu calisma 45 hasta uzerinde gerceklestirildi. Hastalarin yasi ve cinsiyeti kaydedildi. Iki yas grubu incelendi: genc (18-25 yas, n = 23) ve ileri yasli (40-50 yas, n = 22). Dislerin ortodontik seviyelenmesi icin 0.018-inc slotlu onceden ayarlanmis edgewise braketlerde 0.014-inc super elastik nikel-titanyum telleri kullanildi. (Roth prescription, Gemini Metal Brackets, 3M Unitek Corporation, Monrovia, Calif) Takip suresi 1 aydi. Sonuc bir gorsel analog skalasi (VAS) ile baslangicta ve 8 onceden belirlenmis takip noktasinda degerlendirildi (1 saat, 6 saat, 12 saat, 1 gun, 3gun, 7gun, 15gun, 1 ay). Veriler, Friedman, Dunn ve Mann-Whitney testleri kullanilarak degerlendirildi ve anlamlilik seviyesi p 0.05), tum zaman dilimlerinde istatistiksel olarak anlamli farkliliklar bulundu ( p 0.05). Pain was most pronounced at 12th hour, decreased within the course of study and then reached to baseline values at day 30 for both groups. Statistically significant intragroup difference was found for hour 6 and 12, and day 1 and 3 for both groups ( p < 0.05). Conclusion: Older patients who underwent initial phase of orthodontic treatment experienced similar pain pattern as younger patients but had higher VAS scores than that of younger patients. Furthermore, older patients were more likely to estimate their times for pain recovery to be 30 days or more. For overall pain, there was no statistically significant difference between the patients. However, female patients had a significantly higher pain level. Key words: Orthodontic treatment, initial alignment phase, pain, visual analogue scale (VAS), age, gender.

An Accurate Methodology to detect Leaching of Nickel and Chromium Ions in the Initial Phase of Orthodontic Treatment: An in vivo Study.

The aim of this study was to evaluate the release of nickel and chromium ions in human saliva during fixed orthodontic therapy. Ten patients with Angle's Class-I malocclusion with bimaxillary protrusion without any metal restorations or crowns and with all the permanent teeth were selected. Five male patients and five female patients in the age group range of 14 to 23 years were scheduled for orthodontic treatment with first premolar extraction. Saliva samples were collected in three stages: sample 1, before orthodontic treatment; sample 2, after 10 days of bonding sample; and sample 3, after 1 month of bonding. The samples were analyzed for the following metals nickel and chromium using inductively coupled plasma optical emission spectrometry (ICP-OES). The levels of nickel and chromium were statistically significant, while nickel showed a gradual increase in the first 10 days and a decline thereafter. Chromium showed a gradual increase and was statistically significant on the 30th day. There was greatest release of ions during the first 10 days and a gradual decline thereafter. Control group had traces of nickel and chromium. While comparing levels of nickel in saliva, there was a significant rise from baseline to 10th and 30th-day sample, which was statistically significant. While comparing 10th day to that of 30th day, there was no statistical significance. The levels of chromium ion in the saliva were more in 30th day, and when comparing 10th-day sample with 30th day, there was statistical significance. Nickel and chromium levels were well within the permissible levels. However, some hypersensitive individuals may be allergic to this minimal permissible level.

The effect of orthodontic bands or tubes upon periodontal status during the initial phase of orthodontic treatment.

IntroductionOrthodontic bands cause periodontal inflammation. In theory, the use of a buccal tube (bond) instead of a band should prevent or minimize periodontal changes because the bonds are positioned away from the gingival margins.ObjectiveThe primary aim of this study was to investigate the periodontal status of orthodontic bands compared with bonds in the first three months of orthodontic treatment.Materials and methodsTwenty-four orthodontic patients (mean age = 12.6 years) were enrolled in this Randomized Controlled Trial (RCT). Using the cross-mouth technique, bands and bonds were used in opposite quadrants. Periodontal parameters including the presence or absence of Bleeding On Probing (BOP) and Probing Depths (PDs) were taken at the start and three months into treatment.ResultsBands caused a statistically significant change in the Bleeding On Probing (BOP) (P = 0.001 and 0.021) and bonds displayed a statistically insignificant change in the Bleeding On Probing (BOP) (P = 0.125 and 1.00) for the upper and lower arch. The difference in Probing Depths (PDs) between bands and bonds was also statistically significant (P = 0.001).ConclusionMolar bands are associated with greater periodontal inflammation compared with molar bonds in the first three months of fixed orthodontic treatment.

Dental plaque associated with self-ligating brackets during the initial phase of orthodontic treatment: A 3-month preliminary study.

Background:To compare changes in the amount and distribution of dental plaque associated with placement of elastomeric modules over a self-ligating bracket during orthodontic treatment and to relate these changes to the periodontal inflammation.Materials and Methods:A cross-arch randomization trial was carried out at Bristol Dental School, United Kingdom. Clinical measurements of periodontal inflammation and plaque accumulation and microbiological test were done on 24 patients aged 11-14 years [Mean (SD) age = 12.6 (1.01) years] wearing fixed appliances (Damon 2 brackets, Ormco, Orange, CA, USA) at the start and 3 months into fixed orthodontic treatment.Results:In the first 3 months of treatment there was no statistically significant difference in bleeding on probing between incisors with and without elastomeric modules (P = 0.125 and 0.508, respectively). The difference in plaque accumulation was not statistically significant (P = 0.78). The difference in probing depths between the incisors was not statistically significant (P = 0.84). The microbiological analysis showed no difference.Conclusions:Based on this preliminary 3 months study, elastomeric modules were not significantly associated with any increased risk during treatment when compared to self-ligating brackets. The longer term studies are needed to further confirm the findings of the present study.

Modeling Stress-Relaxation Behavior of the Periodontal Ligament During the Initial Phase of Orthodontic Treatment

The periodontal ligament is the tissue that provides early tooth motion as a result of applied forces during orthodontic treatment: a force-displacement behavior characterized by an instantaneous displacement followed by a creep phase and a stress relaxation phase. Stress relaxation behavior is that which provides the long-term loading to and causes remodelling of the alveolar bone, which is responsible for the long-term permanent displacement of the tooth. In this study, the objective was to assess six viscoelastic models to predict stress relaxation behavior of rabbit periodontal ligament (PDL). Using rabbit stress relaxation data found in the literature, it was found that the modified superposition theory (MST) model best predicts the rabbit PDL behavior as compared to nonstrain-dependent and strain-dependent versions of the Burgers four-parameter and the five-parameter viscoelastic models, as well as predictions by Schapery's viscoelastic model. Furthermore, it is established that using a quadratic form for MST strain dependency provides more stable solutions than the cubic form seen in previous studies.

Comparison of root resorption between self-ligating and conventional preadjusted brackets using cone beam computed tomography

To compare the magnitude of external apical root resorption (EARR) of incisors in patients undergoing the initial phase of orthodontic treatment with two sets of brackets. According to the results of the power analysis for sample size calculation, 19 Angle Class I patients (anterior crowding: 3 to 5 mm; mean age: 20.6 years) were included in the study and randomly divided into two groups: group I (n = 11, self-ligating brackets) and group II (n = 8, conventional preadjusted brackets). The degree of EARR was detected in 152 upper and lower incisors by using cone-beam computed tomography (CBCT) scans and a three-dimensional program (Dolphin 11.5, Dolphin Imaging & Management Solutions, Chatsworth, Calif) with 25% level of sensitivity. The CBCT scans were obtained before (T1) and 6 months after initiation of treatment (T2). Differences between and within groups were analyzed by nonpaired and paired t-test, respectively, with 5% significance level. Significant differences were found for both groups between T1 and T2. However, no differences in the degree of EARR were detected between the groups studied. Although EARR has occurred in all teeth evaluated, the bracket design (self-ligating or conventional) did not demonstrate any influence on the results observed.

Electromyographic Analysis of Masseter Muscle after Surgical Correction of Mandibular Prognathism

ABSTRACTSagittal split ramus osteotomy (SSRO) is commonly used for treatment of mandibular prognathism. This study evaluated masseter muscle activity using electromyography device, in patients with mandibular prognathism before and after bilateral SSRO of the mandible.Twelve prognathic patients (five males and seven females; mean age 20.6 years) were examined. Initial phase of orthodontic treatment was completed in all included patients. Electromyographic activity of masseter muscle was recorded during maximum voluntary clenching as follows: First evaluation: 7 days prior to surgery, second evaluation: 3 months after surgery and third evaluation: 6 months after surgery. Electro-myography quantities were significantly decreased 3 months after surgery. Electromyographic activity of masseter muscle was recovered to the preoperative level 6 months after bilateral SSRO of the mandible. SSRO of the mandible is a safe technique for correction of mandibular prognathism and not seriously affects masticatory muscle electromyographic activity.How to cite this articleEshghpour M, Danesh Sani SA. Electromyographic Analysis of Masseter Muscle after Surgical Correction of Mandibular Prognathism. Int J Head and Neck Surg 2012;3(3):121-124.

Disfunções orofaciais nos pacientes em tratamento ortodôntico

OBJETIVO: avaliar a necessidade de intervenção fonoaudiológica nos pacientes em tratamento na clínica ortodôntica da Universidade Federal de Juiz de Fora. MÉTODOS: foram feitos exames clínicos, aplicação de questionário e análise de prontuários clínicos de 42 pacientes em tratamento ortodôntico na Universidade Federal de Juiz de Fora. A primeira fase do presente estudo foi composta pela avaliação da posição habitual da língua, função da respiração, deglutição e fala. Em seguida, foram obtidos dados sobre aspectos morfológicos da oclusão dentária e informações sobre a presença de hábitos orais deletérios. RESULTADOS: notou-se que 92% dos examinados apresentavam alterações na mastigação e na deglutição e 52% tinham alguma disfunção na fala. A comparação gráfica das medidas de cada uma das variáveis sugere que há uma tendência maior a ter alteração na mastigação os indivíduos que se encontram em tratamento ordodôntico há um tempo superior ou igual a 19 meses. O mesmo já não é válido para os indivíduos que apresentaram alterações na fala e deglutição. CONCLUSÃO: Observou-se com o presente estudo a importância da intervenção fonoaudiológica, especialmente nas alterações da mastigação, na fase inicial do tratamento odontológico.

Force Systems in the Initial Phase of Orthodontic Treatment—a Comparison of Different Leveling Archwires

The determination of orthodontically-effective forces and moments places great demands on the technical equipment. Many patients report severe pain after fixed appliance insertion. Since it is assumed that pain from orthodontic appliances is associated with the force and moment levels applied to the teeth and since the occurrence of root resorption is a common therapeutic side effect, it would seem important to know the actual magnitudes of the components of the active orthodontic force systems. The aim of the present study was therefore to measure initial force systems produced by different leveling arch-wires in a complete multi-bracket appliance and to assess whether force and moment levels can be regarded as biologically acceptable or not. The actual bracket position in 42 patients was transferred onto a measurement model. Forces and moments produced by a super-elastic nickel-titanium (NiTi) archwire, a 6-strand stainless steel archwire, and a 7-strand super-elastic NiTi archwire were determined experimentally on different teeth. Average forces and moments produced by the super-elastic NiTi arch wires were found to be the highest. In spite if their larger diameter, the stranded arch wires' average force and moment levels were lower, especially that of the stranded super-elastic archwire. Nevertheless, maximum force levels sometimes exceeded recommended values in the literature and must be considered as too high. The measured arch wires' initial force systems differed significantly depending on the type of archwire and its material structure. Stranded arch wires produced lower force and moment levels, and we recommend their use in the initial phase of orthodontic treatment.